Patent Publication Number: US-2023143993-A1

Title: Architectural-structure coverings, and components thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application makes reference to and claims the benefit of the filing date of pending U.S. provisional patent application No. 63/017,044, filed Apr. 29, 2020, entitled “External Booster for an Architectural-Structure Covering,” and makes reference to and claims the benefit of pending U.S. provisional patent application No. 63/137,230, filed Jan. 14, 2021, entitled “Roller Tube for an Architectural-Structure Covering,” and makes reference to and claims the benefit of pending U.S. provisional patent application No. 63/119,694, filed Dec. 1, 2020, entitled “Covering for Use in an Architectural-Structure Covering,” the entirety of each application is incorporated by reference herein. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to architectural-structure coverings, and more particularly to one or more features for use in an architectural-structure covering. For example, in one embodiment, an improved covering for use in an architectural-structure covering is disclosed. The covering being arranged and configured to be over-rotated in the fully deployed or extended position so that the vanes of the covering disposed between front and rear sheets of the covering are orientated substantially perpendicular to the incoming light (e.g., sunrays). In another embodiment, an improved rotatable member (e.g., a roller tube) for an architectural-structure covering is disclosed. The rotatable member being arranged and configured to prevent premature deployment of a bottom rail. In another embodiment, an external booster for facilitating movement, rotation, deployment, extension, or the like, of a covering of an architectural-structure covering to a fully deployed position is disclosed. 
     BACKGROUND OF THE DISCLOSURE 
     Architectural-structure coverings for architectural openings and/or structures, such as windows, doors, archways, portions of a wall, and the like (collectively an architectural structure without the intent to limit), have taken numerous forms for many years. One known architectural-structure covering includes a covering such as a fabric that is movable between an extended or deployed position and a retracted position. For example, the covering can be vertically extendable or retractable (e.g., able to be lowered or raised, respectively, in a vertical direction) between an extended position and a retracted position for obscuring and exposing the underlying architectural structure. 
     To move the covering between the extended and retracted positions, some architectural-structure coverings include a rotatable member (e.g., a rod, a roller, a tube, etc.). Rotation of the rotatable member in a first direction retracts the covering while rotation of the rotatable member in a second, opposite direction extends the covering. The covering of the architectural-structure covering may be gathered or stacked adjacent to, or wrapped around, the rotatable member. For example, in various embodiments, the covering can either be wrapped about the rotatable member to retract the covering or unwrapped from the rotatable member to extend the covering. Regardless of the form of the covering, rotation of the rotatable member generally causes movement of the covering of the architectural-structure covering. To actuate movement of the rotatable member, and thus the covering of the architectural-structure covering, an operating system may be operably coupled to the rotatable member. 
     The operating system may be operatively associated with an operating element, for example, a cord, a chain, a tilt wand, or the like. The operating element may be manipulated by a human operator to move the covering between the extended and retracted positions. Alternatively, the operating system may include a motorized controller to lower or raise the covering. For example, a motorized drive motor (e.g., an electric motor) can be provided to move the covering between the extended position and the retracted position. In one embodiment, the operating element may include a hand-held remote or the like to actuate the motorized drive motor and/or other aspects of the architectural structure covering. 
     The architectural-structure covering may further include a bottom rail attached to a bottom portion of the covering. The bottom rail may be an elongate member that is coupled to or mounted (such terms may be used interchangeable herein without the intent to limit) to a bottom portion of the covering. The bottom rail may be provided to add weight to the bottom portion of the covering to encourage the covering to drop under a gravitational force during deployment, extension, etc. 
     One known type of architectural-structure covering is a Silhouette® shade manufactured and sold by Hunter Douglas, Inc. Referring to  FIGS.  1 - 4   , the architectural-structure covering  10  includes a head rail assembly  14 , a covering  22 , and a bottom rail  18 . As will be described herein, the architectural-structure covering  10  may also include a second covering  24  and a bottom rail  20  coupled to the second covering  24 . As such, the covering  22  may also be referred to herein as a first covering  22  and the bottom rail  18  may be referred to as a first bottom rail  18 . Covering  24  may also be referred to herein as a second covering  24  and the bottom rail  20  may be referred to as a second bottom rail  20 . 
     The head rail assembly  14  may include two opposing end caps  26   a ,  26   b , which may enclose the ends of the head rail assembly  14  to provide a finished appearance. As will be appreciated, one or more rotatable members (e.g., rotors, rollers, tubes, etc.) may be positioned within the head rail assembly  14  and operatively coupled to the covering. The first covering  22  may extend between the head rail assembly  14  and the first bottom rail  18 . The first bottom rail  18  may extend horizontally along a lower edge of the first covering  22  and may function as a ballast to maintain the first covering  22  in a taut condition and to aid in a gravity-driven extension of the first covering  22 . 
     The first covering  22  may include a vertically suspended front sheet  30  of flexible material (such as sheer fabric), a vertically suspended rear sheet  34  of flexible material, and a plurality of horizontally-extending, vertically-spaced flexible vanes  38 . Each of the vanes  38  may be secured along horizontal lines of attachment with a front edge attached to the front sheet  30  and a rear edge attached to the rear sheet  34 . The front and rear sheets  30 ,  34  and vanes  38  may form a plurality of elongated, vertically-aligned, longitudinally-extending cells, which collectively may be referred to as a cellular panel. In the final, fully extended or deployed position ( FIGS.  2 - 4   ), each of the vanes  38  may extend substantially horizontally between the front and rear sheets  30 ,  34 . 
     Referring to  FIGS.  1  and  2   , the architectural-structure covering  10  is shown with the first covering  22  in two different extended positions.  FIG.  1    depicts the first covering  22  in a partially extended position in which further rotation of the rotatable member in an extending direction moves the front and rear sheets  30 ,  34  generally vertically (relative to each other) to shift the vanes  38  between open and closed configurations. When in the closed or collapsed configuration of  FIG.  1   , the front and rear sheets  30 ,  34  are relatively close together (e.g., the front and rear sheets  30 ,  34  are positioned directly adjacent to each other) and the vanes  38  extend vertically in an approximately coplanar, contiguous relationship with the front and rear sheets  30 ,  34 .  FIG.  2    depicts the first covering  22  in a fully extended or deployed position with the vanes  38  in an open or expanded configuration. In this position, the front and rear sheets  30 ,  34  are horizontally spaced apart from each other with the vanes  38  extending substantially horizontally therebetween. 
     Referring to  FIGS.  3  and  4   , and as previously mentioned, in one or more various embodiments, the architectural-structure covering  10  may also include a second covering  24  positioned rearward of the first covering  22  (e.g., closer to, for example, a window). The second covering  24  may extend between the head rail assembly  14  and a bottom rail  20 . The bottom rail  20  of the second covering  24  may extend horizontally along a lower edge of the second covering  24  and may function as a ballast to maintain the second covering  24  in a taut condition. 
     In use, the first and second coverings  22 ,  24  may be constructed of substantially any type of material and/or constructed in any manner. For example, the first and second coverings  22 ,  24  may be constructed from natural and/or synthetic materials, including fabrics, polymers, and/or other suitable materials. Fabric materials may include woven, non-woven, knits, or other suitable fabric types. The first and second coverings  22 ,  24  may have any suitable level of light transmissivity. For example, the first and second coverings  22 ,  24  may be constructed of transparent, translucent, and/or opaque materials to provide a desired ambience or decor in an associated room. In some examples, the first covering  22  includes first and second sheets  30 ,  34  that are transparent and/or translucent, and vanes  38  that are translucent and/or opaque. In some examples, the second covering  24  is made of a single sheet of material with zero light transmissivity, often referred to as a black-out shade. The second covering  24  may include patterns or designs so that when the second covering  24  is extended behind the first covering  22 , the second covering  24  creates a different aesthetic appearance than the first covering  22  by itself. 
     Additional information on the arrangement and construction of the architectural-structure covering  10  can be found in, for example, U.S. patent application Ser. No. 15/789,014, filed on Oct. 20, 2017, entitled “Covering for Architectural Features, Related Systems, and Methods of Manufacture,” and U.S. patent application Ser. No. 15/339,445, filed on Oct. 31, 2016, now U.S. Pat. No. 10,443,304, entitled “Covering for Architectural Openings with Coordinated Vane Sets,” the entire disclosure of each application is incorporated into the present application in their entirety. 
     In use and as previously mentioned, the first covering  22  and/or the second covering  24  may be operably associated with a rotatable member so that rotational movement of the rotatable member about a longitudinally-extending axis moves the first and/or second coverings  22 ,  24  between the extended and retracted positions. For instance, the first covering  22  may be coupled to and wrappable about a rotatable member so that rotation of the rotatable member in a first direction may retract the first covering  22  and rotation of the rotatable member in a second, opposite direction may extend the first covering  22 . Similarly, the second covering  24  may be operatively coupled with a rotatable member so that rotational movement of the rotatable member about a longitudinally-extending axis moves the second covering  24  between the extended and retracted positions. The first and/or second coverings  22 ,  24  may be wrapped about or unwrapped from a rear side of the rotatable member, with a rear side of the rotatable member positioned between a front side of the rotatable member and a street side of an associated architectural structure. Alternatively, the first and/or second coverings  22 ,  24  may be wrapped about or unwrapped from the front side of the rotatable member. 
     In use, to move the first and/or second covering  22 ,  24 , an operator may manipulate the operating system. For example, as illustrated in the example embodiment of  FIGS.  1 - 4   , the operating system may include an operating element  42 . As will be generally appreciated, to raise or retract the covering such as, for example, the first covering  22  from an extended position, the operator may pull the operating element  42  downward. To extend or lower the first covering  22  from a retracted position, the operator may manipulate the operating element  42  to release a brake, which may allow the covering to automatically lower under the influence of gravity. Alternatively, the operating element  42  may be replaced with an electric motor configured to extend or retract the covering upon receiving an extension or retraction command. For example, the motor may include a gravity lower state to permit the covering to lower via gravity without motor intervention, thereby reducing power consumption. As will be appreciated by one of ordinary skill in the art, the operating system including the operating element may take on numerous forms for controlling movement of a covering. 
     In one embodiment, the second covering  24  may be extended or lowered such as, for example, automatically extended or lowered, when the first covering  22  reaches its fully deployed position. Alternatively, the second covering  24  may include a second operating element for controlling the second covering  24 . 
     In use, positioning of the vanes in the fully deployed or extended position may effect shadow lines due to light encountering the covering. For example, one concern with current coverings such as, for example, the first covering  22  shown in  FIGS.  1 - 4   , is that in the open configuration of the fully extended or deployed position, the vanes  38  extending between the front and rear sheets  30 ,  34  may cause or cast shadow-lines onto the floor of the interior room as the incoming light encounters the covering  22 . Shadow-lines may occur when, for example, incoming light on a higher vane cast a visible shadow through a lower vane and/or when incoming light encounters the horizontal line of attachment between the vanes and the rear sheet of the covering. As a result, in order to prevent the incoming light from casting shadow-lines onto the floor of the interior room, users maintain the covering  22  in the closed configuration (or deploy the optional second covering  24 ). However, in either of these two configurations, view-thru the covering is prevented (e.g., view to the outside is eliminated). 
     In addition, and/or alternatively, referring to  FIG.  5   , in one embodiment, the architectural-structure covering may include a rotatable member  50 . The rotatable member  50  may include an inner roller  60  and an outer roller  70 , and thus may be interchangeably referred to herein as a rotatable member or a dual roller unit  50 . The inner roller  60  may be positioned inside of the outer roller  70 , and the inner and outer rollers  60 ,  70  may be coaxially aligned about the same rotational axis. In use, the second covering  24  may be coupled at a top edge to the inner roller  60 . The outer roller  70  may be generally cylindrical in shape and may surround the inner roller  60 . The first covering  22  may be coupled at a top edge to the outer roller  70 . The outer roller  70  may include a slot  72  extending along a length of the outer roller  70  and in communication with an interior of the outer roller  70 . The slot  72  can permit passage of the second covering  24  during extension and retraction of the second covering  24 . The dual roller unit  50  may be rotatably supported by the opposing end caps  26   a ,  26   b.    
     In use, the first covering  22  may be coupled to and wrappable about the outer roller  70  while the second covering  24  may be coupled to and wrappable about the inner roller  60 . In the fully-retracted positions, the first and second coverings  22 ,  24  may be concealed within the head rail assembly  14 . In this position, the second covering  24  is fully wrapped about the inner roller  60  and the first covering  22  is fully wrapped about the outer roller  70 . To extend the first covering  22  from the head rail assembly  14 , the user may actuate the operating system such as, for example, a drive motor, an operating element, etc. to cause the inner roller  60  to rotate in the extension direction, which in turn causes the outer roller  70  to rotate in the extension direction due at least in part to the weight of the first bottom rail  18  applying a downward force to the first covering  22 . That is, as the first covering  22  extends off the outer roller  70 , the outer roller  70  generally rotates in unison with the inner roller  60 . In use, the first covering  22  extends off of the outer roller  70  in the closed or collapsed configuration in which the front and rear sheets  30 ,  34  are relatively close together, as generally illustrated in  FIG.  1   . Once the first covering  22  is substantially unwrapped from the outer roller  70 , continued rotation of the outer roller  70  in the extension direction moves the front and rear sheets  30 ,  34  generally vertically relative to each other to shift the vanes  38  from the closed configuration to the open configuration, as generally illustrated in  FIG.  2   . When the first covering  22  reaches the fully extended position with the vanes  38  in the open or expanded configuration, the second covering  24  may be extended, as generally illustrated in  FIG.  3   . Due to the weight of the first covering  22  on the outer roller  70 , the outer roller  70  remains stationary (e.g., the outer roller  70  does not rotate). Thus arranged, the inner roller  60  is driven via, for example, a motorized drive motor or a spring-assisted motor. The outer roller  70  is moved due to, for example, the force of gravity, friction caused by the first covering  22  wrapping or unwrapping from the outer roller  70 , etc. 
     Additional information on the operation and construction of a dual roller unit  50  can be found in, for example, U.S. patent application Ser. No. 15/895,061, filed on Feb. 13, 2018, now U.S. Pat. No. 10,781,630, entitled “Covering for an Architectural Opening Having Nested Rollers,” the entire disclosure of which is incorporated into the present application.  FIG.  5    illustrates an example of an embodiment of a dual roller unit  50  including an inner roller  60  and an outer roller  70 .  FIG.  5    illustrating the first covering  22  in the fully extended position so that the bottom rail  20  of the second covering  24  is exposed. 
     For certain types of architectural-structure coverings, such as the Silhouette® shade, gravity alone may be insufficient to fully actuate or open the first covering  22  (e.g., to fully open the first covering  22 ) or to ensure consistent deployment of the first covering  22  to the open configuration. For example, during the final, approximate one-half revolution of the rotatable member in the extension direction, the rotatable member separates the front and rear sheets  30 ,  34 , lifts the front sheet  30 , and lifts a front-side of the vanes  38 . At least a portion of the movement of the front sheet  30  and the vanes  38  opposes gravity, and thus in many circumstances the first covering  22  may not fully open via gravity. Similarly, gravity alone may be insufficient to fully extend other types of architectural-structure coverings. For example, some coverings wrap around and unwrap from a front side of the rotatable member. For these types of shades, a final, approximate one-quarter revolution of the rotatable member rotates the covering from a bottom-dead center location toward the architectural structure in which the covering is raised relative to the bottom-dead center location. The arcuate motion of the covering during this final one-quarter revolution of the rotatable member works against gravity and thus rotational assistance may be needed to overcome the downward gravitational force. 
     Thus, a booster or supplemental revolution assembly (used interchangeably herein without the intent to limit) may be incorporated to ensure that the covering may be extended or deployed to a fully deployed condition. For instance, in certain embodiments, a booster may be used to ensure that the covering such as, for example, the first covering  22 , is consistently deployed to the fully extended or deployed position. Additional information on the operation and construction of a known booster can be found in, for example, U.S. patent application Ser. No. 14/770,204, filed on Aug. 25, 2015, now U.S. Pat. No. 9,739,089, entitled “Covering for an Architectural Opening,” the entire disclosure of which is incorporated into the present application. 
     One disadvantage associated with the booster disclosed in the &#39;204 patent application is that the booster is positioned inside of the rotatable member (e.g., the booster is positioned inside of the interior of the rotatable member). Thus arranged, the booster cannot be used in connection with a dual roller unit. In addition, and/or alternatively, in one or more embodiments, it may be beneficial or desirable to provide additional rotation as compared to the amount of additional rotation provided by the booster of the &#39;204 patent application. 
     Moreover, referring to  FIGS.  6 A and  6 B , one concern associated with the dual roller units is that when the first covering  22  is fully extended and the bottom rail  20  of the second covering  24  is exposed (such as, for example, as illustrated in  FIG.  5   ), the bottom rail  20  of the second covering  24  may prematurely begin to drop from the outer roller  70  of the dual roller unit  50 , which may cause the bottom rail  20  of the second covering  24  to contact the head rail assembly  14  (e.g., since the first covering  22  is fully extended, the bottom rail  20  of the second covering  24  is no longer covered by the first covering  22  and thus, due to gravity, may prematurely release or drop out of a channel formed in the outer roller  70 ). 
     In addition, during use, a time delay (e.g., milli-seconds) may occur between the time when the inner roller  60  is still rotating but the outer roller  70  remains stationary. For example, when a booster is utilized to provide supplemental rotation, a time delay may occur when the inner roller  60  is still rotating but the outer roller  70  is stationary (e.g., before the booster fires). The resulting time delay may result in slack of the second covering  24 , which may allow the bottom rail  20  of the second covering  24  to prematurely release or drop from the outer roller  70 , which may cause the bottom rail  20  of the second covering  24  to contact the head rail assembly  14  when one is present. 
     It is with respect to these and other considerations that the present improvements may be useful. 
     SUMMARY 
     This Summary is provided to introduce in a simplified form, a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. 
     In accordance with one feature of the present disclosure, an external booster for use with an architectural-structure covering is disclosed. In use, the external booster is arranged and configured to operatively engage a rotatable member associated with a covering of the architectural-structure covering to provide additional rotation to the rotatable member, and hence the covering. 
     In one embodiment, the external booster is arranged and configured to transition from a first configuration or a first state of operation (terms used interchangeably herein without the intent to limit) to a second configuration or a second state of operation. In the first configuration, the external booster is arranged and configured to store potential energy. In the second configuration, the external booster releases the stored potential energy in the form of kinetic energy to rotate the rotatable member in a specific direction to effect full extension or deployment of the covering. In one embodiment, the external booster is arranged and configured to transition from the first configuration to the second configuration at a specific covering position during extension or deployment of the covering. 
     In one embodiment, the external booster is arranged and configured to be positioned outside or exterior of the rotatable member, while still being positioned within the head rail assembly of the architectural-structure covering. For example, the external booster may include an anchoring and/or coupling mechanism. In one embodiment, the anchoring mechanism secures the external booster to the one of the end caps of the architectural-structure covering. The coupling mechanism is arranged and configured to rotatably engage the rotatable member. In one embodiment, the external booster may include one or more gears for engaging a gear associated with the rotatable member. 
     In one embodiment, the one or more gears may be arranged and configured as a flexible, compressible, or spring-loaded gear (terms used interchangeably herein without the intent to limit). Thus arranged, the one or more flexible gears are arranged and configured to provide a friction fit meshing with corresponding gears to prevent, or at least, reduce unwanted backlash and/or unwanted clearance. For example, in one embodiment, the one or more gears may include a plurality of cutouts formed in a body thereof. In one embodiment, the plurality of cutouts may be spiral-shaped, alternatively however, other shapes are envisioned. Preferably, the cutouts are arranged and configured to provide a substantially uniform pressure around the gear. Alternatively, and/or in addition, in one embodiment, the one or more gears may be manufactured from a flexible material arranged and configured to enable the flexible gear to flex and/or compress. 
     In one embodiment, the external booster also includes a biasing mechanism and a retention mechanism. The biasing mechanism is arranged and configured with a preloaded resilient force when the external booster is in the first configuration. The biasing mechanism is arranged and configured to remain in the preloaded state until the covering reaches a predetermined position. Thereafter, when the external booster is transitioned to the second configuration, the biasing mechanism is arranged and configured to release its preloaded resilient force causing the retention mechanism to rotate, which causes the rotatable member, and hence the covering associated therewith, to rotate. 
     The retention mechanism may be configured to retain the potential energy or preload in the biasing mechanism until the covering reaches the predetermined position. The retention mechanism may be selectively associated with the anchoring mechanism to either restrict or permit movement of the biasing mechanism. When associated (e.g., coupled) with the anchoring mechanism (e.g., when the external booster is in the first configuration), the retention mechanism restricts movement of the biasing mechanism, thereby maintaining the preload in the biasing mechanism. When not associated (e.g., disconnected or decoupled) with the anchoring mechanism (e.g., when the external booster is in the second configuration), the retention mechanism permits movement of the biasing mechanism, thereby enabling conversion of the stored potential energy into kinetic energy, which rotates the rotatable member and further movement or rotation of the covering to the fully deployed position. 
     In use, the retention mechanism, or at least a portion or element thereof, is movable between a first position and a second position. Movement of the retention mechanism into the first position may connect the biasing mechanism and the anchoring mechanism. Movement of the retention mechanism into the second position may disconnect the biasing mechanism from the anchoring mechanism. 
     Once released, the potential energy or preload of the biasing mechanism may be restored during normal covering operation. For instance, during retraction of the covering, rotation of the rotatable member in the opposite direction may affect movement of the retention mechanism, which in turn may affect movement of the biasing mechanism in a preloading direction. Once a desired preload is achieved, the retention mechanism may move into the first position (e.g., transiting the external booster back to its first configuration) to maintain the preload in the biasing mechanism for use during the next covering operating cycle. When in the first position, the retention mechanism may be positioned so as to not interfere with covering operation. As such, an architecture-structure covering is provided that includes a covering that may be repeatedly lowered via gravity into a fully operational position in a continuous, uninterrupted, smooth action without operator intervention. 
     In one embodiment, an architectural-structure covering is disclosed. The architectural-structure covering comprises a rotatable member, a covering operatively coupled to the rotatable member, the covering being movable between a retracted position and an extended position, and an external booster operatively coupled to the rotatable member. In one embodiment, the external booster comprises a biasing mechanism operably associated with the rotatable member to selectively rotate the rotatable member in an extension direction, the biasing mechanism having a preload, and a retention mechanism associated with the biasing mechanism and operable to release the preload at the extended position, wherein the external booster is spaced apart from the rotatable member, the external booster being coupled to the rotatable member via one or more gears arranged and configured to transfer rotation between the external booster and the rotatable member. 
     In one embodiment, the external booster is arranged and configured to transition from a first configuration to a second configuration, in the first configuration, the external booster stores potential energy, in the second configuration, the external booster releases the stored potential energy to rotate the rotatable member. 
     In one embodiment, the external booster transitions from the first configuration to the second configuration at a predetermined covering position during extension of the covering. 
     In one embodiment, with the external booster in the first configuration, the biasing mechanism is preloaded, and when the external booster is transitioned to the second configuration, the biasing mechanism releases the preload to rotate the rotatable member. 
     In one embodiment, movement of the covering from the extended position to the retracted position, automatically transitions the external booster from the second configuration to the first configuration, and thus preloads the biasing mechanism. 
     In one embodiment, the external booster includes a non-rotatable shaft. 
     In one embodiment, the non-rotatable shaft is arranged and configured to couple to an end plate of a head rail assembly of the architectural-structure covering. 
     In one embodiment, the external booster further comprises a coupling mechanism movable between a first position and a second position, the retention mechanism being coupled to the non-rotatable shaft when the coupling mechanism is in the first position, the retention mechanism being disconnected from the non-rotatable shaft when the coupling mechanism is in the second position. 
     In one embodiment, the biasing mechanism includes a spring guide, a spring cap, and a spring, the spring cap being rotationally fixed to the non-rotatable shaft, the spring guide including a bore arranged and configured to enable the non-rotatable shaft to pass therethrough, the spring being positioned between the spring cap and the spring guide arranged and configured to bias the spring guide away from the spring cap. 
     In one embodiment, in the first configuration, the spring biases the spring guide away from the spring cap, and the spring guide is inhibited from moving, in the second configuration, the spring guide is movable so that the spring applies a force to the spring guide causing the retention mechanism and hence the rotatable member to rotate. 
     In one embodiment, the retention mechanism includes an externally threaded bolt, a traveling nut, and a drive sleeve, the traveling nut being threadably coupled to the externally threaded bolt such that rotation of the traveling nut relative to the externally threaded bolt causes the traveling nut to axially translate along a longitudinal length of the externally threaded bolt, the externally threaded bolt including a bore arranged and configured to pass the non-rotatable shaft to therethrough. 
     In one embodiment, in the first configuration, the externally threaded bolt is inhibited from rotating, and in the second configuration, the externally threaded bolt is permitted to rotate. 
     In one embodiment, the externally threaded bolt is operatively coupled to the spring cap so that, in the second configuration, the spring biases the spring cap causing the spring cap and the externally threaded bolt to rotate in unison. 
     In one embodiment, rotation of the spring cap and the externally threaded bolt causes the traveling nut and the drive sleeve to rotate, the drive sleeve being coupled to one of the one or more gears, so that rotation of the drive sleeve rotates the rotatable member. 
     In one embodiment, rotation of the traveling nut causes the traveling nut to axially translate toward a first end portion of the externally threaded bolt causing the traveling nut to contact a coupling mechanism causes the coupling mechanism to move from a first position to a second position. 
     In one embodiment, the coupling mechanism is a pawl, in the first position, a portion of the pawl is received within a pocket formed in the non-rotatable shaft, in the second position, the portion of the pawl is removed from the pocket formed in the non-rotatable shaft. 
     In one embodiment, axial translation of the traveling nut towards the first end portion of the externally threaded bolt causes the traveling nut to contact the pawl moving the pawl from the first position to the second position. 
     In one embodiment, the pawl includes a pin extending from a rear surface of the pawl, the traveling nut includes a pathway formed in a contacting surface thereof, interaction between the pin and the pathway causing the pawl to move from the first position to the second position. 
     In one embodiment, the covering is a first covering and the rotatable member includes an outer roller operatively associated with the first covering and an inner roller positioned within the outer roller, the inner roller operatively associated with a second covering. 
     In one embodiment, the first covering is movable between the retracted position and the extended position, and between an open configuration and a closed configuration, the first covering including a front sheet, a rear sheet, and a plurality of vanes extending between the front and rear sheets, in the closed configuration, the front and rear sheets are positioned directly adjacent to each other and the plurality of vanes extend vertically in an approximately coplanar, contiguous relationship with the front and rear sheets, in the open configuration, the front and rear sheets are spaced apart from each other with the plurality of vanes extending therebetween, and the external booster is arranged and configured to provide supplemental rotation to ensure that the first covering is rotated to the open configuration. 
     In one embodiment, an external booster for use with an architectural-structure covering is disclosed. The architectural-structure covering includes a rotatable member and a covering coupled to the rotatable member. The covering is movable between a first position and a second position via rotation of the rotatable member. In one embodiment, the external booster is movable between a first state of operation and a second state of operation, in the first state of operation the external booster is arranged and configured to store potential energy, and in the second state of operation, the external booster releases the stored potential energy to rotate the rotatable member in a predetermined direction to effect additional rotation of the covering, the external booster is spaced apart from the rotatable member, the external booster being coupled to the rotatable member via one or more gears arranged and configured to transfer rotation between the external booster and the rotatable member, and the external booster is arranged and configured to transition from the first state of operation to the second state of operation at a predetermined covering position during extension or deployment of the covering. 
     In one embodiment, the one or more gears may be arranged and configured as a flexible gear arranged and configured to provide a friction fit meshing with corresponding gears to prevent, or at least, reduce unwanted backlash and/or unwanted clearance. For example, in one embodiment, the one or more gears may include a plurality of cutouts formed in a body thereof. In one embodiment, the plurality of cutouts may be spiral-shaped alternatively however, other shapes are envisioned. Preferably, the cutouts are arranged and configured to provide a substantially uniform pressure around the gear. Alternatively, and/or in addition, in one embodiment, the one or more gears may be manufactured from a flexible material so that a central portion of the flexible gear is arranged and configured to flex and/or compress (e.g., center portion can be rendered flexible while the tooth geometry (e.g., outer teeth) and the inner diameter of the hub or bore retains its original molded size and shape). 
     In addition, and/or alternatively, in accordance with another feature of the present disclosure, a rotatable member (e.g., roller tube) of an architectural-structure covering is disclosed. The rotatable member including a scoop arranged and configured to create a pocket or cradle to hold, secure, maintain, etc. a position of a bottom rail to prevent, or at least minimize, premature deployment of the bottom rail. For example, in one embodiment, the scoop may be arranged and configured to create a pocket or cradle to maintain a position of a bottom rail relative to an outer roller to enable the bottom rail to rotate with the outer roller past the head rail assembly without contacting the head rail assembly. Thereafter, on the next rotational pass when the scoop is positioned within a specified, predetermined range of positions, the scoop enables the bottom rail to release or drop from the outer roller within the specified, predetermined position. 
     In one embodiment, an architectural-structure covering is disclosed. The architectural-structure covering comprising a rotatable member, a covering, and a bottom rail. The covering including a top portion and a bottom portion, the top portion operatively coupled to the rotatable member. The covering being movable between a retracted position and an extended position. The bottom rail is operatively coupled to the bottom portion of the covering. The rotatable member includes a scoop defining a pocket arranged and configured to maintain the bottom rail within the pocket when the rotatable member is not positioned within a predetermined or desired rotational range and, when positioned within the predetermined or desired rotational range, the scoop is arranged and configured to enable the bottom rail to deploy from the rotatable member. 
     In one embodiment, the scoop includes a first arm and a second arm, the first arm extending away from an outer surface of the rotatable member, the second arm extending at an angle relative to the first arm so that the pocket is defined between an inner surface of the first and second arms and the outer surface of the rotatable member. 
     In one embodiment, the scoop includes an approximate “L” or “C” shape. 
     In one embodiment, the scoop includes an opening in communication with the pocket, the opening positioned in a leading direction of rotation of the rotatable member. 
     In one embodiment, the bottom rail and the scoop include corresponding bumps, the corresponding bumps arranged and configured to contact each other when the rotatable member is not positioned within the predetermined or desired rotational range to maintain the bottom rail within the pocket, the corresponding bumps arranged and configured to enable the bottom rail to deploy from the pocket when the bottom rail is positioned within the predetermined or desired rotational range. 
     In one embodiment, the rotatable member is an outer roller of a dual roller unit, the dual roller unit further comprising an inner roller positioned within the outer roller, the covering is a second covering wrappable about the outer roller, the architectural-structure covering further comprising a first covering wrapped about the inner roller. 
     In one embodiment, the scoop is arranged and configured to maintain the bottom rail within the pocket when the rotatable member is not positioned within the predetermined or desired rotational range so that the bottom rail moves past a head rail assembly of the architectural-structure covering without contacting the head rail assembly. 
     In one embodiment, the predetermined or desired rotational range is between 8:00 and 12:00 for a rotatable member rotating in a counterclockwise direction. 
     In one embodiment, the predetermined or desired rotational range is between 9:00 and 11:00 for a rotatable member rotating in a counterclockwise direction. 
     In one embodiment, the predetermined or desired rotational range is between 12:00 and 4:00 for a rotatable member rotating in a clockwise direction. 
     In one embodiment, the predetermined or desired rotational range is between 1:00 and 3:00 for a rotatable member rotating in a clockwise direction. 
     In addition, and/or alternatively, in accordance with another feature of the present disclosure, an improved covering arranged and configured to be used in an architectural-structure covering is disclosed. In one embodiment, the architectural-structure covering includes a rotatable member and the covering. The rotatable member includes a front, room-facing surface and a rear surface opposite the front surface, the rear surface of the rotatable member being positioned closer to an underlying architectural-structure, in use, than the front, room-facing surface. The covering is operably coupled to the rotatable member, the covering being wrapped about and unwrapped from the rear surface of the rotatable member so that the covering can be moved between a retracted position and a fully deployed position. 
     In one embodiment, the covering includes a front vertical sheet having a height and width, a rear vertical sheet having a height and a width and operably coupled and moveable relative to the front vertical sheet, and a plurality of vanes extending between the front and rear sheets. Each vane includes a top layer, a bottom layer, a front edge, and a rear edge. Each vane is coupled to the front sheet along a first horizontal line of attachment and to the rear sheet along a second horizontal line of attachment. In the fully deployed position, the first horizontal line of attachment is spaced a vertical distance D 1  above the second horizontal line of attachment and the front edge is spaced a vertical distance from the first horizontal line of attachment and the rear edge is spaced is a vertical distance from the second horizontal line of attachment. 
     In one embodiment, in the fully deployed position, the vanes are orientated perpendicular to incoming sunrays. 
     In one embodiment, the front edge of the vane is positioned above the rear edge of the vane. 
     In one embodiment, the front edge is positioned adjacent to, and separate from, the front sheet, the rear edge is positioned adjacent to, and separate from, the rear sheet. 
     In one embodiment, the vane extends downward from the first horizontal line of attachment to the front edge and the vane extends upward from the second horizontal line of attachment to the rear edge. 
     In one embodiment, the distance from the first horizontal line of attachment to the front edge is a distance D 2  and the distance from the second horizontal line of attachment to the rear edge is a distance D 3 , distance D 2  and distance D 3  being the same. 
     In one embodiment, distance D 2  and distance D 3  are between 1/16″ to ⅜″, and preferably ⅛″ to 3/16″. 
     In one embodiment, the distance from the first horizontal line of attachment to the front edge is a distance D 2  and the distance from the second horizontal line of attachment to the rear edge is a distance D 3 , distance D 2  being different from distance D 3 . 
     In one embodiment, distance D 2  and distance D 3  are between 1/16″ to ⅜″, and preferably ⅛″ to 3/16″. 
     In one embodiment, the front and rear sheets are manufactured from a transparent material, the vanes are manufactured from one of an opaque or partially opaque material. 
     In one embodiment, the front and rear sheets are manufactured from a sheer material. 
     In one embodiment, the covering is movable between a closed configuration and an open configuration, in the closed configuration, the front and rear sheets are positioned relatively close together and the vanes extend vertically in an approximately coplanar, contiguous relationship with the front and rear sheets, in the open configuration, the front and rear sheets are horizontally spaced apart from each other with the vanes extending between the front and rear sheets. 
     In one embodiment, the architectural-structure covering further comprises a booster or supplemental revolution assembly arranged and configured to operatively couple to the rotatable member to apply an additional torque to the rotatable member to further move the front sheet relative to the rear sheet. 
     In one embodiment, each vane is manufactured from an integral sheet of material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view illustrating a known example of an embodiment of an architectural-structure covering, the architectural-structure covering including a first covering and a second covering, the first covering shown in a partially extended position, the first covering shown in a closed configuration; 
         FIG.  2    is an alternate, perspective view of the architectural-structure covering of  FIG.  1   , the first covering shown in a fully extended or deployed position, the first covering shown in an open configuration; 
         FIG.  3    is an alternate, perspective view of the architectural-structure covering of  FIG.  1   , the second covering shown in a partially extended position; 
         FIG.  4    is an alternate, perspective view of the architectural-structure covering of  FIG.  1   , the second covering shown in a fully extended or deployed position; 
         FIG.  5    is a cross-sectional view illustrating a known example of an embodiment of a dual roller unit that may be used in combination with the architectural-structure covering of  FIG.  1   , the dual roller unit including an inner roller coupled to the second covering and an outer roller coupled to the first covering; 
         FIGS.  6 A and  6 B  schematically illustrate operation of the dual roller unit of  FIG.  5   ; 
         FIGS.  7 A- 7 E  illustrate various perspective views of an embodiment of a covering in accordance with one or more features of the present disclosure, the covering may be used in connection with the architectural-structure covering of  FIG.  1    (e.g., the covering may be used in place of the first covering of  FIG.  1   ); 
         FIGS.  8 A- 8 E  illustrate various cross-sectional views of the covering of  FIGS.  7 A- 7 E ; and 
         FIG.  9    illustrates an enlarged cross-sectional view of a portion of the covering of  FIGS.  7 A- 7 E  in the fully deployed (e.g., over-rotated) position. 
         FIGS.  10 A- 10 E  are various cross-sectional views illustrating an outer roller that may be used with the dual roller unit of  FIG.  5   , the outer roller including a scoop in accordance with one or more features of the present disclosure; 
         FIG.  11    is a detailed, perspective view of a portion of the architectural-structure covering of  FIG.  1    incorporating an example of an embodiment of an external booster in accordance with one or more aspects of the present disclosure; 
         FIG.  12    is a reverse perspective view of the external booster shown in  FIG.  11   , the external booster coupled to the architectural-structure covering of  FIG.  1   ; 
         FIG.  13    is a side view of the external booster shown in  FIG.  11   ; 
         FIG.  14    is an exploded, perspective view of the external booster shown in  FIG.  11   ; 
         FIG.  15    is a cross-sectional view of the external booster shown in  FIG.  11   , the cross-sectional view taken along line XV-XV in  FIG.  13   ; 
         FIGS.  16 A- 16 H  are various view illustrating movement of a pawl between a first position and a second position,  FIG.  16 A  illustrating the pawl in the first position,  FIG.  16 E  illustrating the pawl in the second position; 
         FIG.  16 I  is a view of an alternate example embodiment of the pawl illustrated in the second position, the system including an optional bumper, 
         FIG.  17 A  is an exploded, perspective view of an example of an embodiment of a pawl and a nut in accordance with one or more aspects of the present disclosure; 
         FIG.  17 B  is a side, exploded, perspective view of the pawl and nut shown in  FIG.  17 A ; 
         FIG.  18    is a perspective view of an example embodiment of a flexible gear in accordance with one or more features of the present disclosure; 
         FIG.  19 A  illustrates a conventional gear shown in a nominal position where the gear teeth and/or pitch diameters of adjacent gears perfectly match; 
         FIG.  19 B  illustrates conventional gears where the center-to-center offset distance is designed and configured to compensate for variances in materials and/or tolerances to avoid interference between corresponding meshed teeth of adjacent gears; 
         FIG.  19 C  illustrates a flexible gear as shown in  FIG.  18   , the flexible gear incorporating interfering gear teeth and/or overlapped pitch diameter in accordance with one or more features of the present disclosure; 
         FIG.  19 D  illustrates a flexible gear as shown in  FIG.  18   , the flexible gear incorporating an offset center-to-center offset distance arranged and configured to slightly change or adjust as the flexible gear rotates in accordance with one or more features of the present disclosure; 
         FIGS.  20 A and  20 B  illustrate an example embodiment of first and second flexible gears as shown in  FIG.  18   , the first and second flexible gears coupling an external booster to a rotatable member in accordance with one or more features of the present disclosure; and 
         FIG.  20 C  illustrates an alternate example embodiment of a flexible gear as shown in  FIG.  18   , the flexible gear coupling an external booster to a rotatable member in accordance with one or more features of the present disclosure. 
     
    
    
     The drawings are not necessarily to scale. The drawings are merely representations, not intended to portray specific parameters of the disclosure. The drawings are intended to depict exemplary embodiments of the disclosure, and therefore are not be considered as limiting in scope. In the drawings, like numbering represents like elements. 
     DETAILED DESCRIPTION 
     Various features, aspects, or the like of an architectural-structure covering will now be described more fully hereinafter with reference to the accompanying drawings, in which one or more features will be shown and described. It should be appreciated that the various features may be used independently of, or in combination, with each other. It will be appreciated that the various features as disclosed herein may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will convey certain illustrations of the features to those skilled in the art. 
     Referring to  FIGS.  7 A- 9   , in accordance with one separate and distinct aspect of the present disclosure that may be used separately from, or in combination with, the other aspects of an architectural-structure covering disclosed herein (e.g., the separate and distinct aspect may be used in combination with the other features described herein (e.g., scoop and/or external booster), or may be used with a conventional architectural-structure covering having all or some of the features disclosed herein), an improved covering  110  for use in an architectural-structure covering  100  is disclosed. 
     As will be described in greater detail below, a covering according to the present disclosure includes a vertically suspended front sheet, a vertically suspended rear sheet, and a plurality of horizontally-extending, vertically-spaced flexible vanes. Each of the vanes may be secured along horizontal lines of attachments such as, for example, an adhesive line, to each of the front and rear sheets. As such, in use, the front and rear sheets and vanes may form a plurality of elongated, vertically-aligned, longitudinally-extending cells, which collectively may be referred to as a cellular panel. However, in contrast to known conventional coverings where, in the final, fully extended or deployed position, the vanes extend substantially horizontal between the front and rear sheets, in accordance with one or more features of the present disclosure, in the final, fully extended or deployed position, the covering is arranged and configured to be over-rotated so that the vanes are positioned substantially perpendicular to the incoming light (e.g., sunrays). 
     In one embodiment, the horizontal lines of attachment of the vanes to the front and rear sheets are spaced a distance from a front edge or portion of the vanes and a rear edge or portion of the vanes. Thus, the front and rear edges of the vanes are spaced a distance from the horizontal lines of attachment. Placement of the attachment (e.g., attachment lines or adhesion lines) of the vanes to the front and rear sheets (e.g., distancing or spacing the horizontal lines of attachments of the vanes from the front and rear ends of the vanes, respectively) also ensures that the layers (e.g., first top layer and second bottom layer) of each vane properly separate in the over-rotated position. 
     Thus arranged, the covering is arranged and configured so that in the open configuration of the fully extended position, the front edge of the vanes can be over-rotated relative to a position of the rear edge of the vanes such that the front edge of the vane is positioned vertically above the rear edge of the vane, the horizontal lines of attachment between the front sheet and the vanes reside above the placement of their attachment to the horizontal lines of attachment between the rear sheet and the vanes, and the front and rear edges of the vanes are spaced a distance from their respective horizontal lines of attachments thereby positioning the vanes substantially perpendicular to the incoming light (e.g., sunrays). 
     In one embodiment, during use, the covering may be coupled to and wrappable about a rotatable member so that rotation of the rotatable member in a first direction retracts the covering and rotation of the rotatable member in a second, opposite direction extends the covering. In accordance with one or more features of the present disclosure, the covering may be wrapped about or unwrapped from a rear side of the rotatable member, with a rear side of the rotatable member positioned between a front or room-facing side of the rotatable member and an associated underlying architectural structure (e.g., window side). 
     In use, the covering may be over-rotated by any suitable device, mechanism, system, method, etc. now known or hereafter developed. For example, in one embodiment, the architectural-structure covering may include a booster or supplemental revolution assembly operatively coupled with the rotatable member of the covering. In use, the booster or supplemental revolution assembly is operatively couple to the rotatable member of the covering to apply an additional torque or rotation to the rotatable member to further move, rotate, etc. the rotatable member when the covering reaches its fully deployed position (e.g., the booster or supplemental revolution assembly applies an additional torque to the rotatable member to provide additional rotation to the rotatable member and thus the covering). One example of an external booster or supplemental revolution assembly will be disclosed herein in connection with  FIGS.  11 - 17 B . 
     Referring to  FIGS.  7 A- 8 E , various views of an embodiment of an architectural-structure covering  100  including a covering  110  in accordance with one or more features of the present disclosure is shown. As shown and described herein, the architectural-structure covering  100  includes a rotatable member  105  operatively coupled to the covering  110 . As illustrated, the covering  110  includes a front sheet  120 , a rear sheet  140 , and a plurality of vanes  160  extending between the front and rear sheets  120 ,  140 . 
     As illustrated, the covering  110  may include a top edge or portion  112  operatively coupled to the rotatable member  105  and a bottom edge or portion operatively coupled to a bottom rail (not shown). In use, the front sheet  120  may be connected at connection point  122  to the rotatable member  105  and at another connection point to the bottom rail. Similarly, the rear sheet  140  may be connected at connection point  142  to the rotatable member  105  and at another connection point to the bottom rail. In use, as previously mentioned, rotation of the rotatable member  105  causes the covering  110  to wind and unwind (e.g., wrap and unwrap) about the rotatable member  105  so that the covering  110  moves between a retracted position and a deployed or extended position. As illustrated, in one embodiment, the covering  110  is arranged and configured to unwrap from a rear side of the rotatable member  105  (e.g., side positioned closer to the underlying architectural-structure (i.e., counter-clockwise rotation of the rotatable member in  FIGS.  8 A- 8 E )). 
     In use, in the fully deployed or extended position, the covering  110  is movable from a closed configuration (depicted in  FIGS.  7 A and  8 A ) wherein the front and rear sheets  120 ,  140  of the covering  110  are relatively close together (e.g., the front and rear sheets  120 ,  140  are positioned directly adjacent to each other) and the vanes  160  extend vertically in an approximately coplanar, contiguous relationship with the front and rear sheets  120 ,  140 , to an open configuration (depicted in  FIGS.  7 B- 7 E and  8 B- 8 E ), wherein the front and rear sheets  120 ,  140  are spaced apart from each other with the vanes  160  extending between the front and rear sheets  120 ,  140 . 
     In contrast to conventional coverings including a front sheet, a rear sheet, and a plurality of vanes extending therebetween such as, for example, the first covering  22  shown in  FIGS.  1 - 4    wherein in the fully deployed or extended position, the plurality of vanes extend substantially horizontally between the front and rear sheets, in accordance with one or more features of the present invention, in the fully deployed or extended position ( FIGS.  7 E and  8 E ), the plurality of vanes  160  are arranged and configured so that the vanes  160  are positioned substantially perpendicular to the incoming light (e.g., sunrays) L. Thus arranged, in use, a front portion or edge  162  of the vane  160  is positioned above a rear portion or edge  164  of the vane  160 . That is, a front portion or edge  162  of a vane  160  may be rotated, or over-rotated, relative to a rear portion or edge  164  of the vane  160  so that, in the fully deployed position, the front portion or edge  162  of the vane  160  is positioned vertically above the rear portion or edge  164  of the vane  160  (e.g., the front portion or edge  162  of the vane  160  is positioned closer to the rotatable member  105  as compared to the rear portion or edge  164  of the vane  160 ) thereby enabling the vanes  160  to be positioned substantially perpendicular to the incoming light (e.g., sunrays) L. 
     More particularly, as best illustrated in  FIG.  9   , the covering  110  may include a plurality of vanes  160  extending between the front and rear sheets  120 ,  140 . As illustrated, in the open configuration, each of the vanes  160  define an opened cell  180 . For example, as illustrated, in one embodiment, each cell  180  defines an enclosed area without requiring any portion of the front or rear sheets  120 ,  140 . Thus each cell  180  may be constructed by an integral sheet of material. Alternatively, each cell  180  may be formed by multiple sheets of material coupled together. As illustrated, in one embodiment, each vane  160  includes first and second layers  160 A,  160 B (e.g., top and bottom layers). In use, the front and rear edges  162 ,  164  are defined by the joint, crease, coupling, etc. of the first and second layers  160 A,  160 B of the vanes  160 . In one embodiment, each vane  160  may be formed as an integral piece of material with a fold at one edge and a slit, weld, joint, coupling etc. at the other end such as, for example, a fold at the front edge  162  and a slit, weld, joint, coupling etc. at the rear edge  164 , or vice-versa. In use, the fold may also be arranged and configured to facilitate biasing of the cell  180  to the open configuration to provide improved aesthetics. In one embodiment, by utilizing double layers (e.g., first and second layers  160 A,  160 B) such as, for example, transparent layers, incoming light L is diffused eliminating, or at least greatly minimizing, harsh shadows (e.g., incoming light is diffused by the top layer and subsequently by the bottom layer). 
     With continued reference to  FIG.  9   , in accordance with one or more features of the present disclosure, each of the vanes  160  may be connected to the front sheet  120  along a first horizontal line of attachment  166  (e.g., an adhesive line) and to the rear sheet  140  along a second horizontal line of attachment  168  (e.g., vane  160  is coupled to the front sheet  120  along a first horizontal line of attachment  166  while the vane  160  is coupled to the rear sheet  140  along a second horizontal line of attachment  168 ). In use, placement of the first and second horizontal lines of attachment  166 ,  168  ensure that the first and second layers  160 A,  160 B of each vane  160  are separated in the open configuration. As illustrated, when the cells are in the fully open configuration, the first horizontal line of attachment  166  between the vane  160  and the front sheet  120  may be vertical spaced by a height or distance D 1  from the second horizontal line of attachment  168  between the vane  160  and the rear sheet  140 . In one embodiment, the distance D 1  may be approximately 2.5 inches. 
     Moreover, as illustrated in  FIG.  9   , in the open configuration, the front edge  162  of each vane  160  is positioned adjacent to, but separated from, the front sheet  120  and the rear edge  164  is positioned adjacent to, but separated from, the rear sheet  140 . In use, the first layer  160 A may extend downward from the first horizontal line of attachment  166  to the front edge  162  of the vane  160 . The second layer  160 B may extend upwards from the second horizontal line of attachment  168  to the rear edge  164  of the vane  160 . In one embodiment, the front edge  162  may be spaced a distance D 2  from or below the first horizontal line of attachment  166 . The rear edge  164  may be spaced a distance D 3  from or above the second horizontal line of attachment  168 . As such, by distancing the first and second horizontal lines of attachment  166 ,  168  from the front and rear edges  162 ,  164 , respectively, the connection points to the front and rear sheets  120 ,  140  are positioned away from and therefore off-center from the front and rear edges  162 ,  164  of the vanes  160  thereby facilitating movement and control of the opening and closing of the cells  180 . In one embodiment, distance D 2  and distance D 3  may be the same. Alternatively, distance D 2  and distance D 3  may be different. In one embodiment, distance D 2  and distance D 3  may be between ⅛″ to 3/16″, although this is but one configuration and different dimensions can be used such as, for example, between 1/16″ to ¼″, 5/16″, ⅜″, etc. In use, distance D 2  and distance D 3  can be based, in part, on a function of the flexibility of the materials used coupled with an objective aesthetic evaluation. 
     Thus arranged, in contrast to conventional coverings such as illustrated in  FIGS.  1 - 4   , in accordance with features of the present disclosure, the covering  110  is arranged and configured to be over-rotated so that the first horizontal line of attachment  166  with the front sheet  120  is positioned above the second horizontal line of attachment  168  with the rear sheet  140  and with the front and rear edges  162 ,  164  of the vanes  160  spaced a distance from the first and second horizontal line of attachments  166 ,  168 , respectively. As such, in the fully deployed position, the vanes  160  may be positioned substantially perpendicular to the incoming light (e.g., sunrays) L. 
     In one embodiment, the final, fully deployed or extended position, the covering  110  may be supplementally rotated beyond a point at which conventional coverings are rotated. Thus, for example, when used in combination with a booster, such as, for example, an external booster as will be described in greater detail below, during the final stage of operation, the covering  110  may be supplementally rotated a predetermined amount (such as a final one-eighth revolution, one-quarter revolution, one-half revolution, three-quarters revolution, amounts therebetween, or other suitable amounts) as the covering  110  approaches the fully deployed or extended position so that the covering  110  is over-rotated as compared to conventional arrangements (e.g., as best illustrated by comparing  FIGS.  7 D and  8 D  to  FIGS.  7 E and  8 E ). For example, the booster may be configured to rotate the rotatable member  105  and thus the covering by approximately 330 degrees, although other ranges of rotation are envisioned. 
     In use, depending on the material(s) used in the manufacturing of the covering  110 , opening and closing of the cells  180  may vary the light transmissivity of the covering  110 , as will be described in greater detail below. For example, when the cells  180  are closed ( FIGS.  7 A and  8 A ), each cell  180  may be substantially compressed and the plurality of vanes  160  may be substantially parallel with each of the front and rear sheets  120 ,  140 . In some embodiments, a length or body of each of the cells  180  may be adjacent to each other or partially overlap so that the cells  180  may form a pseudo middle sheet positioned between the front and rear sheets  120 ,  140 . When the cells  180  are open to at least some extent ( FIGS.  7 B- 7 E and  8 B- 8 E ), each cell  180  may be at least partially angled with respect to at least one of the front and rear sheets  120 ,  140 . In an open configuration, the cells  180  may then provide an insulative aspect by trapping air in each cell  180 . Further, the cells  180  may reduce or diffuse shadows created by the structure of the covering  110  on one side from being as noticeable on the other side of the covering  110 . In other words, shadow lines caused by light encountering the covering  110  on the outer side thereof, whether or not at a particular angle of incidence, may be reduced as viewed from the interior side of the covering  110 . 
     In use, over-rotating the vanes  160  provides a “shading” attitude as the vane  160  is positioned more perpendicular relative to the incoming light (e.g., sunrays) L (e.g., inside-edge of the vane is tilted above horizontal). Thus, in the fully deployed position, the covering  110  is oriented to allow light to be admitted through the gaps or spaces between the cells  180 . In accordance with one or more features of the present disclosure, by enabling the covering  110  to over-rotate so that the vanes of the covering are orientated substantially perpendicular to the incoming light (e.g., sunrays) L, in the fully deployed position, the vanes  160  are arranged and configured to provide optimal positioning while avoiding, or at least minimizing, shadows below the vanes. 
     That is, in use, the structure of the cells  180  of the vanes  160  diffuses shadows formed from light transmitted through the covering  110 . In accordance with the present disclosure, shadows may be substantially prevented from being transmitted through the covering even in the open configuration of the fully extended position. This may be especially apparent in examples where the front sheet  120  and the rear sheet  140  are a transparent or sheer material, or otherwise have a high light transmissivity. 
     In conventional coverings, during use, as light encounters the rear sheet (e.g., if the covering is positioned over a window), the light may be transmitted through the rear sheet and the horizontal line of attachment may block part of the light. However, other light rays may pass through the rear sheet without be blocked, thus resulting in shadow lines (e.g., the light being blocked by the horizontal line of attachment may form a shadow). Thereafter, as the vane is positioned above the shadow, the shadow may be transmitted to the front sheet of the covering and may be visible on the front side or surface of the covering. In use, the shadow may appear black and/or darkened portions or spots of the front side of the covering, which may be aesthetically unpleasing. Additionally, the spots may cause the material of the front sheet to fade unevenly due to light exposure. 
     In contrast, in accordance with features of the present disclosure, by positioning the vanes  160  substantially perpendicular to the incoming light L, the covering  110  of the present disclosure eliminates, or at least minimizes, darkened spots due to harsh shadows. 
     In use, the fully deployed position of the covering may be associated with a final revolution of the rotatable member so that further rotation of the rotatable member repositions at least a portion of the covering. For example, further rotation of the rotatable member over-rotates the covering such that, for example, the front edge  162  of the vane  160  coupled to the front sheet  120  is rotated, or over-rotated, to a position above the rear edge  164  of the vane  160  coupled to the rear sheet  140  so that, in the fully deployed position, the front edge  162  of the vane  160  is positioned above the rear edge  164  of the vane  160 . 
     While the covering  110  of the present disclosure has been shown and described in the present disclosure for use with a particular architectural-structure covering, it should be appreciated that the covering  110  should not be limited to any particular type of architectural-structure covering. It is envisioned that the covering  110  according to one or more features of the present disclosure may be used in connection with other types of architectural-structure coverings. Thus, the present disclosure should not be limited to any particular type of architectural-structure covering unless specifically claimed. For example, the covering  110  may be used in an architectural-structure covering including dual rotatable members and dual coverings as illustrated in  FIGS.  1 - 4   . Alternatively, the covering  110  may be used in an architectural-structure covering including a single rotatable member and covering. 
     The covering including the front sheet, the rear sheet, and the vanes may be manufactured from any suitable material now known or hereafter developed. For example, the covering may be constructed from natural and/or synthetic materials, including fabrics, polymers, and/or other suitable materials. Fabric materials may include woven, non-woven, knits, or other suitable fabric types. Additionally, the front sheet, rear sheet, and vanes may have varying translucent properties, varying from blackout, opaque, to partially opaque, or clear. In some instances, the front sheet and the rear sheet may have an increased light translucence as compared with the vanes, so that when the vanes are closed the light translucence of the covering may be varied. For example, the front and rear sheets may be made from a transparent or sheer material while the vanes may be manufactured from a transparent, a blackout, an opaque, or a partially opaque material. 
     In one embodiment, when used in combination with a second covering, the first and second coverings may have different levels of light transmissivity. For example, the first and second coverings may be constructed of transparent, translucent, and/or opaque materials to provide a desired ambience or decor in an associated room. In one embodiment, the first covering includes front and rear sheets that are transparent and/or translucent, and vanes that are translucent and/or opaque. In some examples, the second covering is made of a single sheet of material with zero light transmissivity, often referred to as a black-out shade. The second covering may include patterns or designs so that when the second covering is extended behind the first covering, the second covering creates a different aesthetic appearance than the first covering by itself. 
     Referring to  FIGS.  10 A- 10 E , in accordance with another separate and distinct aspect of the present disclosure that may be used separately from, or in combination with, the other aspects of an architectural-structure covering disclosed herein (e.g., the separate and distinct aspect may be used in combination with the other features described herein (e.g., covering and/or external booster), or may be used with a conventional architectural-structure covering having all or some of the features disclosed herein), an improved rotatable member  200  for use in an architectural-structure covering is disclosed. 
     While features of the rotatable member will be shown and described in the present disclosure for use with an outer roller of a dual roller unit, it should be appreciated that the features of the rotatable member should not be limited to any particular type of rotatable member. For example, it is envisioned that the features of the rotatable member may be used in connection with other types of rotatable member for use with architectural-structure coverings. Thus, the present disclosure should not be limited to an outer roller of a dual roller unit unless specifically claimed. 
     Referring to  FIGS.  10 A- 10 E , an example of an embodiment of a rotatable member  200  for use in an architectural-structure covering such as, for example, architectural-structure covering  10 , is disclosed. In one embodiment, the rotatable member  200  may be arranged and configured as an outer roller in a dual roller unit. Thus, in use, the rotatable member  200  may be arranged and configured to replace the outer roller  70  in dual roller unit  50 , and may be interchangeably referred to herein as a rotatable member  200  or an outer roller  200 . 
     In accordance with one or more features of the present disclosure, the outer roller  200  includes a scoop  210  arranged and configured to create a cradle or pocket  220  to position, maintain, hold, secure, etc. (terms used interchangeably herein without the intent to limit) the bottom rail  20  of the second covering  24  so that the bottom rail  20  is prevented from dropping, deploying, releasing, separately, etc. (terms used interchangeably herein without the intent to limit) from the outer roller  200  until the second covering  24  is properly positioned to be deployed. As such, in use, the scoop  210  is arranged and configured to prevent, or at least minimize, premature deployment, or uncontrolled or unplanned deployment, of the bottom rail  20  and the second covering  24 . For example, in one embodiment, the scoop  210  prevents, or at least inhibits, separation of the bottom rail  20  from the outer roller  200  and thus prevents, or at least inhibits, the bottom rail  20  from contacting the head rail assembly  14 . 
     In use, the scoop  210  enables the bottom rail  20  to reside within the cradle or pocket  220  as the outer roller  200  is rotated. That is, the scoop  210  takes up any slack in the second covering  24  caused by rotation of the inner roller while the outer roller remains stationary. That is, as previously discussed, in the second from last rotation of the outer roller, the first covering  22  is fully deployed and, as such, the bottom rail  20  of the second covering  24  is revealed (e.g., no longer wrapped by any portion of the first covering  22 ). Thus, the bottom rail  20  of the second covering  24  can separate or deploy from the outer roller. However, deployment of the second covering  24  should be maintained until the bottom rail  20  of the second covering  24  reaches a predetermined, desired position. For example, in one embodiment, deployment of the second covering  24 , and thus of the bottom rail  20 , from the outer roller should not occur until the bottom rail  20  reaches a predetermined or desired position. In one embodiment, for rotatable members rotating in the counterclockwise position, the predetermined or desired position may be approximately 12:00 to 8:00, preferably 11:00 to 9:00 (when viewed in  FIGS.  6 A and  6 B  with the underlying architectural-structure on the left). As will be appreciated, for rotatable members rotating in the clockwise position, the predetermined or desired position may be approximately 12:00 to 4:00, preferably 1:00 to 3:00 (when viewed in  FIGS.  6 A and  6 B  with the underlying architectural-structure on the left). Thus, in use, the scoop  210  is arranged and configured to allow the bottom rail  20  of the second covering  24  to deploy when positioned within the predetermined or desired range of positions, but prevent, or at least inhibit, the bottom rail  20  of the second covering  24  when outside of the predetermined or desired range of position. That is, the scoop  210  is arranged and configured to prevent unintended, premature deployment of the bottom rail. For example, the scoop  210  is arranged and configured to prevent premature deployment of the bottom rail  20  of the second covering  24 , which may cause the bottom rail  20  to contact the head rail assembly  14  resulting in unwanted noise, unintended damage, or a combination thereof, as schematically shown in  FIGS.  6 A and  6 B . Thus arranged, for example, the scoop  210  prevents the bottom rail  20  of the second covering  24  from deploying initially when the first covering  22  is fully deployed. In this manner, the scoop  210  holds the bottom rail  20  of the second covering  24  in position so that the bottom rail  20  of the second covering  24  may pass by the head rail assembly  14  without contacting the head rail assembly  14 . Thereafter, upon subsequent rotation of the outer roller  200 , the scoop  210  enables the bottom rail  20  to deploy. 
     In one embodiment, as illustrated in  FIGS.  10 A- 10 E , the scoop  210  includes a first arm or portion  230  and a second arm or portion  240 . The first arm or portion  230  may extend away from the outer roller  200  (e.g., the first arm or portion  230  extends away from an outer surface  202  of the outer roller  200 ). The second arm or portion  240  extends at an angle relative to the first arm or portion  230 . For example, in one embodiment, the scoop  210  may include an “L” or “C” shape, although this is but one configuration. Thus arranged, the scoop  210  defines the cradle or pocket  220  between the outer surface  202  of the outer roller  200  and an inner surface  242  of the second arm or portion  240  and inner surface  232  of the first arm or portion  230 . The cradle or pocket  220  can be arranged and configured to hold the bottom rail  20  in close proximity to the outer roller  200  so that, during rotation, the bottom rail  20  is prevented from premature deployment so that, for example, during rotation, the bottom rail  20  may pass by the head rail assembly  14  without contacting thereof (e.g., scoop  210  creates a pocket or cradle to allow slack in the second covering  24  while not allowing the bottom rail  20  to deploy from the outer roller  200 ). 
     During rotation of the outer roller  200 , and hence the scoop  210 , the scoop  210  includes an opening  222  in communication with the cradle or pocket  220 . The opening  222  can be oriented in the direction of rotation of the outer roller  200  so that, when positioned within the predetermined or desired range, the bottom rail  20  of the second covering  24  may deploy from the cradle or pocket  220  via the force of gravity. 
     In one embodiment, the scoop  210  and the bottom rail  20  may include corresponding bumps, projections, or the like  250 , to maintain the bottom rail  20  within the cradle or pocket  220 . Thus arranged, during use, as illustrated in  FIG.  10 D , when the bottom rail  20  is positioned outside of the predetermined or desired range, the corresponding bumps  250  formed on the scoop  210  and the bottom rail  20  contact, engage, etc. with each other to prevent the bottom rail  20  from slipping out of the cradle or pocket  220 . For example, as illustrated in  FIG.  10 D , with the bottom rail  20  positioned at substantially 6:00 (when viewed with the underlying architectural-structure on the left and with the rotatable member rotating counterclockwise), the corresponding bumps  250  formed on the scoop  210  and the bottom rail  20  contact, engage, etc. with each other to prevent deployment of the bottom rail  20 . However, as illustrated in  FIG.  10 E , when the bottom rail  20  is positioned within the predetermined or desired range, the bottom rail  20  aligns itself relative to the scoop  210  so that the corresponding bumps  250  do not contact, engage, etc. thereby enabling the bottom rail  20  to deploy from the outer roller  200 . For example, as illustrated in  FIG.  10 E , with the bottom rail  20  positioned at substantially 9:00 (when viewed with the underlying architectural-structure on the left and with the rotatable member rotating counterclockwise), the corresponding bumps  250  formed on the scoop  210  and the bottom rail  20  do not contact, engage, etc. with each other to enable deployment of the bottom rail  20 . 
     In one non-limiting example embodiment, the architectural-structure covering may include a covering arranged and configured to be over-rotated so that the front portion of the vanes may be positioned above the rear portion of the vanes so that the vanes are positioned substantially perpendicular to the incoming sunrays as previously described. The architectural-structure covering may also include a booster such as, for example, an external booster as will be described in greater detail herein, to provide supplemental rotation to facilitate a fully deployed condition (e.g., over-rotation of the vanes). In use, the scoop may be positioned and timed with the booster to pick up any slack in the second covering. That is, during deployment of the first covering, the inner and outer rollers rotate in unison. However, with the first covering fully extended but prior to firing or activation of the booster, a brief time delay may occur when the inner roller continues to rotate but before the booster fires to rotate the outer roller (e.g., milli-seconds), which may result in movement of the inner roller relative to the outer roller (e.g., approximately 1/16″ or more of rotation) causing the second covering to begin deploying from the inner roller. Generally speaking, this may cause slack in the second covering, which may cause the bottom rail of the second covering to separate from the outer roller and thus contact the head rail assembly. However, by properly positioning the scoop on the outer roller and timing the position of the scoop with the firing of the booster, the scoop is arranged and configured to maintain the position of the bottom rail of the second covering accommodating for the slack in the second covering so that the bottom rail of the second covering may pass through the head rail assembly. Thereafter, the bottom rail may slip from the scoop and deploy. 
     Referring to  FIGS.  11 - 17 B , in accordance with another separate and distinct aspect of the present disclosure that may be used separately from, or in combination with, the other aspects of an architectural-structure covering disclosed herein (e.g., the separate and distinct aspect may be used in combination with the other features described herein (e.g., covering and/or scoop), or may be used with a conventional architectural-structure covering having all or some of the features disclosed herein), an external booster for use in an architectural-structure covering is disclosed. 
     As will be described in greater detail below, an external booster according to the present disclosure may be arranged and configured to operatively engage the covering of an architectural-structure covering. For example, the external booster may be coupled via one or more gears to an end of a rotatable member associated with the covering. In use, the external booster may be arranged and configured to transition from a first configuration to a second configuration. In the first configuration, the external booster may be arranged and configured to store potential energy. In the second configuration, the external booster may be arranged and configured to release the stored potential energy in the form of kinetic energy. The external booster may be arranged and configured to transition from the first configuration to the second configuration at a predetermined covering position during extension or deployment of the covering. In use, the kinetic energy may be utilized to rotate the rotatable member in a specific direction to effect full extension or deployment of the covering. 
     Referring to  FIG.  11   , an example of an embodiment of an architectural-structure covering such as, for example, architectural-structure covering  10 , including an external booster  300  in accordance with one or more aspects of the present disclosure is shown. As shown and described herein, the external booster  300  is arranged and configured to work in conjunction with an architectural-structure covering  10 . In particular, certain aspects of the external booster  300  have been arranged and configured so that the external booster  300  may be used in connection with a dual roller unit for operatively moving first and second coverings such as, for example, first and second coverings  22 ,  24 . In particular, the covering, such as, for example, the first covering  22 , may include a front sheet  30 , a rear sheet  34 , and a plurality of vanes  38  extending between the front and rear sheets  30 ,  34 , as previously described. As previously mentioned, in the fully deployed or extended position, the first covering  22  is movable from a closed configuration (depicted in  FIG.  1   ) wherein the front and rear sheets  30 ,  34  of the first covering  22  are relatively close together (e.g., the front and rear sheets  30 ,  34  are positioned directly adjacent to each other) and the vanes  38  extend vertically in an approximately coplanar, contiguous relationship with the front and rear sheets  30 ,  34 , to an open configuration (depicted in  FIG.  2   ), wherein the front and rear sheets  30 ,  34  are horizontally spaced apart from each other with the vanes  38  extending substantially horizontally therebetween. In one embodiment, the external booster  300  may be used with a covering arranged and configured to over-rotate as previously described herein in connection with  FIGS.  7 A- 9   . 
     In use, movement of the first covering  22  from the retracted position to a partially extended position to the fully extended position, wherein the first covering  22  is transitioned from the closed configuration to the open configuration, may occur, for example, via gravity. As such, the motion of the covering  22  may not be controlled or driven. In such instances, variations due to the size and weight of the covering  22  may exist, which may adversely affect the appearance of the architectural-structure covering  10 . In addition, in one or more embodiments, over-rotation of the covering  22  in the open configuration may be desired. For example, in one or more embodiments, it may be aesthetically desirable to have a front edge of a vane coupled to the front sheet rotated, or over-rotated, to a position above a rear edge of the vane coupled to the rear sheet so that, in the fully deployed position, the front edge of the vane is positioned above the rear edge of the vane rotate as previously described herein in connection with  FIGS.  7 A- 9   . In either event, the external booster  300  may be utilized to operatively couple to the covering  22  such as, for example, the rotatable member  50  (e.g., the outer roller  70  of a dual roller unit  50 ) of the covering  22  to apply an additional torque or rotation to the rotatable member  50  to move, rotate, etc. the rotatable member  50  so that the covering  22  reaches its fully deployed position (e.g., the external booster  300  applies an additional torque to the rotatable member  50  to provide additional rotation to the rotatable member  50  to ensure that the covering  22  opens and travels to a limit stop as desired). 
     While the external booster  300  is shown and described in the present disclosure for use with a particular covering, it should be appreciated that the external booster  300  should not be limited to any particular type of architectural-structure covering. It is envisioned that the external booster  300  according to one or more aspects of the present disclosure may be used in connection with other types of architectural-structure coverings. Thus, the present disclosure should not be limited to any particular type of architectural-structure covering unless specifically claimed. 
     Referring to  FIGS.  11 - 15   , as will be described in greater detail herein, the external booster  300  may include an anchoring and/or coupling mechanism  320 , a biasing mechanism  350 , and a retention mechanism  400 . 
     As will be described in greater detail, in use, the anchoring or coupling mechanism  320  is arranged and configured to secure the external booster  300  to the architectural-structure covering  10 . For example, the anchoring or coupling mechanism  320  may include a shaft  322  for engaging one of the end caps  26  of the architectural-structure covering  10 . By engaging the end cap  26  of the architectural-structure covering  10 , the external booster  300  is arranged and configured to be positioned outside or exterior to the rotatable member  50 . Thus arranged, the external booster  300  also includes one or more coupling mechanisms  330  for rotatably engaging the rotatable member  50 . For example, the external booster  300  may include one or more gears  332  for engaging a gear  52  associated with the rotatable member  50 . 
     The biasing mechanism  350  may be preloaded with a resilient force and may remain in a preloaded state until the covering  22  reaches a predetermined extended position (e.g., the fully deployed position). That is, the biasing mechanism  350  may be arranged and configured so that when the external booster  300  is in the first configuration, the biasing mechanism  350  is preloaded with a resilient force. Thereafter, when the external booster  300  is transitioned to the second configuration, the biasing mechanism  350  is arranged and configured to release its preloaded resilient force, which in turn causes the retention mechanism  400  to rotate, which causes the rotatable member  50 , and hence the covering  22  associated therewith, to rotate. 
     The biasing mechanism  350  may include a biasing member  352  (such as a compression spring, an extension spring, a torsion spring, etc.) or any other suitable energy storage member, thus the biasing member  352  may be interchangeably referred to herein as a spring  352 . In use, the predetermined extended position of the covering  22  (e.g., the point at which the external booster  300  may be configured to transition from the first configuration to the second configuration) may be associated with a final revolution of the rotatable member  50  so that further rotation of the rotatable member  50  repositions at least a portion of the covering  22 . For example, further rotation of the rotatable member  50  may laterally separate a Silhouette® shade (e.g., cause the covering  22  to move from the closed configuration to the open configuration as previously described in connection with  FIGS.  1  and  2   ). Alternatively, for example, further rotation of the rotatable member  50  may over-rotate the covering  22  such that, for example, the front edge of the vane coupled to the front sheet is rotated, or over-rotated, to a position above the rear edge of the vane coupled to the rear sheet so that, in the fully deployed position, the front edge of the vane is positioned above the rear edge of the vane (e.g., over-rotating the vanes provides a “shading” attitude as the vane is positioned more perpendicular relative to the sun (inside-edge of the vane is tilted above horizontal)), as previously described herein in connection with  FIGS.  7 A- 9   . In one embodiment, the biasing member  352  may be preloaded by rotating a first end of the biasing member  352  relative to a second end of the biasing member  352 , thereby imparting a preload on the biasing member  352 . The preloaded biasing member  352  may be biased in the extension direction. 
     The retention mechanism  400  may be configured to retain the potential energy or preload in the biasing mechanism  350  until the covering  22  reaches the predetermined extended position. The retention mechanism  400  may be selectively associated with the anchoring mechanism  320  to either restrict or permit movement of the biasing mechanism  350 . When associated with the anchoring mechanism  320  (e.g., when the external booster  300  is in the first configuration), the retention mechanism  400  may restrict movement of the biasing mechanism  350 , thereby maintaining the preload in the biasing mechanism  350 . When not associated with the anchoring mechanism  320  (e.g., when the external booster  300  is in the second configuration), the retention mechanism  400  may permit movement of the biasing mechanism  350 , thereby enabling conversion of the stored potential energy into kinetic energy, which may affect rotation of the rotatable member  50  and further movement (e.g., extension) of the covering  22  to the fully deployed position. 
     During use, at least a portion or an element of the retention mechanism  400  may be movable between a first position and a second position. For example, the retention mechanism  400 , or at least a portion or element thereof, may be slidable, pivotable, and/or rotatable between the first and second positions. Movement of the retention mechanism  400 , or at least a portion or element thereof, into the first position may couple the biasing mechanism  350  and the anchoring mechanism  320  (e.g., positioning the external booster  300  in the first configuration). Movement of the retention mechanism  400 , or at least a portion or element thereof, into the second position may disconnect the biasing mechanism  350  from the anchoring mechanism  320  (e.g., positioning the external booster  300  in the second configuration). The first and second positions of the retention mechanism  400  may be axially spaced, circumferentially spaced, radially spaced, or any combination thereof. 
     Once released, the potential energy or preload of the biasing mechanism  350  may be restored during normal covering operation. For example, during retraction of the covering  22 , reverse rotation of the rotatable member  50  may affect movement of the retention mechanism  400 , which in turn may affect movement of the biasing mechanism  350  in a preloading direction. Once a desired preload is achieved, the retention mechanism  400  may move into the first position (e.g., positioning the external booster  300  in the first configuration) to maintain the preload in the biasing mechanism  350  for use during the next covering operating cycle. When in the first position, the retention mechanism  400  may be positioned so as to not interfere with covering operation. As arranged, an architecture-structure covering  10  is provided that includes a covering  22  that may be repeatedly lowered via gravity into a fully operational position in a continuous, uninterrupted, smooth action without operator intervention. 
     With continued reference to  FIGS.  11 - 15   , the architectural-structure covering  10  may include an external booster  300 . The external booster  300  may be assembled as a single, modular unit that couples to one end of the head rail assembly  14  and rotatably couples with an end of the rotatable member  50 . The external booster  300  (which may be referred to as a module, system, or unit) may be pre-assembled and thus simplify on-site installation of the architectural-structure covering  10 . The external booster  300  may be incorporated into a new architectural-structure covering  10  or added to an existing or installed, architectural-structure covering  10  (i.e., retrofit applications). 
     With continued reference to  FIGS.  11 - 13  and  15   , the external booster  300  is shown in an assembled configuration. As illustrated, given the nature and space constraints of certain rotatable members  50  such as, for example, a dual roller unit including an inner roller positioned within an outer roller, as previously described herein, the external booster  300  is arranged and configured to be positioned exterior to the rotatable member  50 . As such, as previously mentioned, the external booster  300  may include an anchoring mechanism  320 . For example, in one embodiment, the external booster  300  includes a shaft  322  arranged and configured to couple to one of the end caps  26  of the head rail assembly  14  of the architectural-structure covering  10 , although it is envisioned that the external booster  300  may be mounted to the architectural-structure covering  10  in other ways. For example, the shaft  322  may include an enlarged, first end portion  324  arranged and configured to attach to an end cap  26 . For example, the enlarged, first end portion  324  may include axially extending splines or projections  325  configured to engage a corresponding recess, opening, or the like formed in the end cap  26 . Alternatively, the shaft  322  may be coupled to the end caps  26  by any other now known or hereinafter developed mechanism such as, for example, a snap-fit connection, a press-fit connection, fasteners, etc. The external booster  300  may extend parallel with a central axis of the rotatable member  50 . In use, in one embodiment, the shaft  322  is non-rotatably coupled to the end cap  26  of the head rail assembly  14 . As such, the shaft  322  may be interchangeably referred to herein as a non-rotatable shaft  322 . For example, the shaft  322  may be keyed to the end cap  26 , although other mechanisms for preventing relative rotation between the shaft  322  and the end cap  26  may be utilized. 
     In addition, as illustrated, the external booster  300  is arranged and configured to couple to the rotatable member  50  such as, for example, the outer roller of a dual roller unit so that rotation from the external booster  300  is transferred to the outer roller, and vice versa. In use, the external booster  300  may be arranged and configured to rotatably couple to the rotatable member  50  (e.g., outer roller) by any suitable mechanism now known or hereafter developed. For example, as shown, the external booster  300  includes one or more gears  332  to couple the external booster  300  to the rotatable member  50 . That is, for example, the rotatable member  50  may include a first gear  52  arranged and configured to rotate in unison with the rotatable member  50 , and thus with the covering  22 . The external booster  300  may also include a second gear  332  arranged and configured to rotate in unison with the external booster  300 . One or more intermediate or idler gears  334  may be positioned between the first gear  52  of the rotatable member  50  and the second gear  332  of the external booster  300 . Thus arranged, in use, rotation of the first gear  52  is transferred to the second gear  332  via the intermediate or idler gear  334 , and vice-versa. Alternatively, in use, if reverse torque is necessary such as, for example, if the external booster  300  is mounted to the opposite, end cap  26  of the head rail assembly  14  of the architectural-structure covering  10 , an additional, second idle gear may be provided. 
     In use, the external booster  300  may be configured to rotate the rotatable member  50  a specific amount (such as a final one-eighth revolution, one-quarter revolution, one-half revolution, three-quarters revolution, amounts therebetween, or other suitable amounts) as the covering  22  approaches a fully extended position. In one embodiment, the external booster  300  is configured to rotate approximately 330 degrees, as will be appreciated by one of ordinary skill in the art, the amount of rotation to the rotatable member  50  can be altered based on the gear ratios of gears  52 ,  332 ,  334 . 
     Referring to  FIGS.  14  and  15   , in one embodiment, the biasing mechanism  350  of the external booster  300  may include a spring guide  360 , a spring cap  370 , and a biasing member (e.g., a spring)  352 . As illustrated, the spring guide  360  includes a first end portion  362 , a second end portion  364 , and a central portion  366  positioned between the first and second end portions  362 ,  364 . In addition, the spring guide  360  includes a bore  368  extending from the first end portion  362  to the second end portion  364 , the bore  368  being sized and configured to enable the shaft  322  to pass therethrough. As illustrated, the first end portion  362  may be enlarged relative to the second end portion  364 . In use, as will be described in greater detail below, the spring guide  360  is keyed to a bolt  410  of the retention mechanism  400  so that in use, rotation of the spring guide  360  rotates the bolt  410 . 
     Referring to  FIGS.  14  and  15   , in one embodiment, the spring cap  370  includes a first end portion  372 , a second end portion  374 , and a central portion  376  positioned between the first and second end portions  372 ,  374 . In addition, the spring cap  370  includes an interior cavity  378  for enclosing at least a portion of the spring guide  360  and the spring  352 . In addition, as illustrated, the spring cap  370  includes a bore  380  sized and configured to enable the shaft  322  to pass therethrough. In use, the spring cap  370  is keyed to the shaft  322  so that in use, rotation of the spring cap  370  is inhibited. 
     With continued reference to  FIGS.  14  and  15   , in one embodiment, as previously mentioned, the biasing member  352  may be in the form of a spring such as, for example, a compression spring, an extension spring, a torsion spring, etc. Alternatively, it is envisioned that the biasing member may be in the form of any other suitable energy storage member. Thus, as used herein, biasing member and spring are used interchangeably without the intent to limit. As illustrated, the spring  352  includes a first end portion  354  and a second end portion  356 . In addition, the spring  352  includes an interior cavity  358  arranged and configured to enable the spring guide  360  and the shaft  322  to pass therethrough. Thus, as illustrated, the spring  352  may be positioned about the central portion  366  of the spring guide  360 . In use, the first end portion  354  of the spring  352  is coupled, contacts, etc. the first end portion  362  of the spring guide  360  such as, for example, a backside of the enlarged first end portion  362 . Similarly, the second end portion  356  of the spring  352  may be coupled to the second end portion  374  of the spring cap  370 . For example, a tang formed on the first end portion  354  of the spring  352  may be received within a channel formed in the spring guide  360 . Similarly, a tang formed on the second end portion  356  of the spring  352  may be received within a channel formed in the spring cap  370 , although any other suitable coupling structures may be used. In use, the second end portion  356  of the spring  352  is rotatably fixed to the spring cap  370 . 
     Thus arranged, with the external booster  300  in the first configuration, the spring  352  may be preloaded to apply a force to the spring guide  360 . However, because the spring guide  360  is inhibited from rotating (e.g., as will be described in greater detail herein, the spring guide  360  is keyed to a bolt  410  of the retention mechanism  400 , which in the first configuration is coupled to the non-rotatable shaft  322 ), the spring  352  remains in the preloaded state. That is, in use, as will be described in greater detail herein, with the covering  22  in the retracted position (e.g., with the external booster  300  in the first configuration), the spring  352  is preloaded (e.g., the spring  352  is arranged and configured to apply a torque to the spring guide  360  however, because the spring guide  360  is prevented from rotating, the spring  352  remains preloaded). 
     Thereafter, when the external booster  300  is transitioned to the second configuration, the spring  352  applies a force (e.g., torque) to the spring guide  360 , which is turn causes the retention mechanism  400  to rotate, which rotates the rotatable member  50  and the covering  22  (e.g., as will be described in greater detail below, when the external booster  300  is in the second configuration, the bolt  410  of the retention mechanism  400  is decoupled from the non-rotatable shaft  322  thereby enabling the spring guide  360  and the bolt  410  to rotate, which rotates a nut  430  and a drive sleeve  450  of the retention mechanism  400 ). 
     Referring to  FIGS.  14  and  15   , in one embodiment and as previously noted, the retention mechanism  400  of the external booster  300  may include a bolt  410 , a traveling nut  430 , and a drive sleeve  450 . The retention mechanism  400  may also include a pawl  470 . As illustrated, the bolt  410  includes a first end portion  412 , a second end portion  414 , and a central portion  416  positioned between the first and second end portions  412 ,  414 . As illustrated, the bolt  410  also includes an externally threaded section  418  (e.g., external threads extend across a majority of the length of the central portion  416 , as such the bolt  410  may also be referred to as an externally threaded bolt). In use, as will be described in greater detail below, the external threads formed on the bolt  410  are arranged and configured to threadably engage the traveling nut  430 . In addition, the bolt  410  includes a bore  420  extending from the first end portion  412  to the second end portion  414 , the bore  420  being sized and configured to enable the shaft  322  to pass therethrough. As illustrated, the first end portion  412  may be enlarged relative to the second end portion  414 . In use, as will be described in greater detail below, with the external booster  300  in the first configuration, the bolt  410  is inhibited from rotating, however when the external booster  300  is transitioned from the first configuration to the second configuration, the bolt  410  is permitted to rotate. 
     With continued reference to  FIGS.  14  and  15   , the drive sleeve  450  is rotatably coupled to the rotatable member  50  of the architectural-structure covering  10  via, for example, one or more gears  52 ,  332 ,  334 . As such, in use, rotation of the drive sleeve  450  rotates the rotatable member  50 , and vice-versa. As illustrated, in one embodiment, the drive sleeve  450  includes a first end portion  452 , a second end portion  454 , and a central portion  456  positioned between the first and second end portions  452 ,  454 . The first end portion  452  can include the gear  332 . In addition, the drive sleeve  450  can include an interior cavity  458  for enclosing at least a portion of the shaft  322 , the bolt  410 , and the traveling nut  430 . 
     The traveling nut  430  may be threadably engaged to the bolt  410 . For example, the traveling nut  430  may be threadably mounted onto the threaded section  418  of the bolt  410 . In use, rotation of the traveling nut  430  relative to the bolt  410  causes the traveling nut  430  to axially translate along a longitudinal length of the bolt  410 . In addition, the traveling nut  430  is keyed to the drive sleeve  450  so that the nut  430  and the drive sleeve  450  rotate in unison. Thus arranged, during retraction of the covering  22 , rotation of the rotatable member  50  rotates the drive sleeve  450 , which causes the nut  430  to axially translate toward the second end portion  414  of the bolt  410  (e.g., to the right in  FIG.  15   ). During extension of the covering  22 , the traveling nut  430  axially translates towards the first end portion  412  of the bolt  410  (e.g., to the left in  FIG.  15   ). As will be appreciated by one of ordinary skill in the art, these movements could be reversed. 
     As will be described in greater detail below, movement of the covering  22  from the retracted position to the extended position causes the traveling nut  430  to axially translate toward the first end portion  412  of the bolt  410  causing the traveling nut  430  to contact the pawl  470 , which causes the pawl  470  to move from a first or engaged position to a second or disengaged position. 
     In the first position, the pawl  470  is in engagement with the non-rotatable shaft  322  and as a result, rotation of the bolt  410  relative to the non-rotatable shaft  322  is prevented. In the second position, the pawl  470  is decoupled from the non-rotatable shaft  322 . As such, rotation of the bolt  410  relative to the non-rotatable shaft  322  is enabled. Movement of the pawl  470  from the first position to the second position causes the external booster  300  to transition from the first configuration to the second configuration. Thus, movement of the covering  22  from the retracted position to the extended position causes the traveling nut  430  to contact the pawl  470 , which causes the pawl  470  to release the non-rotatable shaft  322 , thus enabling the bolt  410  to rotate due to the preloaded torque built up in the spring  352 . As such, with the pawl  470  in the second position, released from the non-rotatable shaft  322 , the spring  352  biases and rotates the spring guide  360  causing the spring guide  360  and the bolt  410  to rotate, which in turn rotates the nut  430  and the drive sleeve  450 . Rotation of the drive sleeve  450  rotates the rotatable member  50 , and hence the covering  22 , of the architectural-structure covering  10  to further rotate the covering  22  to the fully deployed position. 
     Similarly, movement of the covering  22  from the fully deployed position to the retracted position, causes the traveling nut  430  to axially translate towards the second end portion  414  of the bolt  410  and away from the first end portion  412  of the bolt  410  causing the traveling nut  430  to rotate in the opposite direction, which causes the pawl  470  to move from the second position to the first position. As such, movement of the covering  22  from the fully deployed position to the retracted position causes the pawl  470  to reengage the non-rotatable shaft  322  thus preventing the bolt  410 , and hence the spring guide  360  from rotating. Thus arranged, the external booster  300  can be transitioned from the second configuration to the first configuration. In addition, initial movement of the covering  22  from the fully deployed position to the retracted position causes the bolt  410  and the spring guide  360  to rotate in the opposite direction thereby compressing the spring  352 , preloading the spring  352  for the next operating cycle (e.g., initial rotation of the pawl  470  and the nut  430  before the pawl  470  reengages the non-rotatable shaft  322  compresses and preloads the springs  352 ). As such, with the pawl  470  in the first position, coupled to the non-rotatable shaft  322 , the spring  352  is once again preloaded. 
     Referring to  FIGS.  16 A- 16 H , an example embodiment of a locking mechanism for coupling and disconnecting the bolt  410  and the non-rotatable shaft  322  is illustrated. As previously mentioned, in the first configuration of the external booster  300 , the spring  352  is preloaded. Since the bolt  410  is rotationally coupled to the non-rotatable shaft  322 , however, the bolt  410  is prevented from rotating, which prevents the spring guide  360  from moving. In the second configuration of the external booster  300 , the bolt  410  is decoupled from the shaft  322  so that the bolt  410  can rotate relative to the non-rotatable shaft  322 . Thus arranged, in the second configuration of the external booster  300 , the spring  352  biases the spring guide  360 , which rotates the bolt  410 , the traveling nut  430 , and the drive sleeve  450  to rotate, which in turn rotates the rotatable member  50  and the covering  22 . 
     In use, the locking mechanism may be any suitable mechanism for rotationally engaging and disengaging the bolt  410  from the shaft  322 . For example, as illustrated and as previously mentioned, the locking mechanism may be a pawl  470 . In use, the pawl  470  may be movable such as, for example, pivotable from a first or engaged position to a second or disengaged position. With reference to  FIGS.  16 A- 16 H , various views illustrating movement of the pawl  470  from the first or engaged position to the second or disengaged position are shown. As illustrated, the pawl  470  may include a head portion  480 . In the first position, the head portion  480  of the pawl  470  may be received within a pocket  500  formed in the non-rotatable shaft  322 . In this position, the pawl  470  is rotationally coupled to the non-rotatable shaft  322  so that relative rotation between the bolt  410  and the non-rotatable shaft  322  is prevented. 
     Referring to  FIG.  16 I , in one embodiment, the nut  530  may include a bumper  575  located in the pocket  510  thereof. In use, as the pawl  470  moves outwards, and the spring charge is released, the pawl  470  contacts the bumper  575  causing the bumper  575  to compress, absorbing some of the impact or shock. In use, the bumper  575  may be manufactured from any suitable material such as, for example, a softer durometer material. Thus arranged, in use, the bumper  575  is arranged and configured to reduce noise when the booster fires. 
     Referring to  FIGS.  17 A and  17 B , as illustrated, the pawl  470  may include a projection, a pin, etc.  475  extending from a rear surface  474  of the pawl  470 . In use, the traveling nut  430  includes a contacting surface  432  having a pathway, a groove, a recess, or the like  434  formed therein (terms used interchangeably herein without the intent to limit). As the contacting surface  432  of the traveling nut  430  contacts the rear surface  474  of the pawl  470 , the pathway  434  interacts with the pin  475  extending from the rear surface  474  of the pawl  470 . This interaction between the pin  475  and the pathway  434  guides movement of the pawl  470  as the traveling nut  430  continues to rotate so that the head portion  480  of the pawl  470  moves out of the pocket  500  formed in the shaft  322 , as illustrated in, for example,  FIG.  16 E  (e.g., the pin  475  is arranged and configured to ride along the pathway  434  formed in the contacting surface  432  of the traveling nut  430 ). Once the pawl  470  is moves out of the pocket  500 , the bolt  410  and the non-rotatable shaft  322  are rotatably decoupled. As such, the preload force in the spring  352  is released, which causes the spring guide  360 , the bolt  410 , the traveling nut  430 , and the drive sleeve  450  to rotate, which causes the rotatable member  50  to rotate via the interconnecting gears such as, for example, gears  52 ,  332 ,  334 , or flexible gears  600  as will be described in greater detail below. As will be appreciated, this results in additional rotation being transmitted to the covering  22  to ensure that the covering  22  is in the fully deployed position. That is, in operation, as the covering  22  approaches a predetermined extended position, the traveling nut  430  axially translates along the threaded section  418  of the bolt  410  toward the pawl  470 . The external booster  300  is mechanically toleranced and timed so that as the covering  22  reaches a predetermined covering position, the pathway  434  contacts the pin  475  and pivots the pawl  470  from the first or engaged position to the second or disengaged position, thereby disengaging the pawl  470  from the pocket  500  formed in the non-rotatable shaft  322 . In one embodiment, the predetermined covering position (e.g., limit stop) can be changed for different products (e.g., different limit stops can be provided or adjusted) by adjusting the rotatable member  50  to the desired limit stop position prior to attaching the external booster  300  to the end cap  26 . 
     In use, and as best illustrated in  FIG.  16 H , the traveling nut  430  and pawl  470  are arranged and configured to rotate until reaching a limit stop, which prevents the pawl  470  from reengaging the pocket  500  when rotating in the extension direction. As previously mentioned, and as illustrated in  FIGS.  16 A- 16 H , once released, the traveling nut  430  and the pawl  470  are arranged and configured to rotate approximately 330 degrees, although other ranges of rotation are envisioned. 
     Subsequent rotation of the covering  22  from the fully deployed position to the retracted position causes the rotatable member  50  and hence the drive sleeve  450  and the traveling nut  430  to rotate in the opposite direction (e.g., clockwise direction as viewed in  FIGS.  16 A- 16 H ). When rotated in the clockwise direction, an abutment surface  512  of an opposing pocket  510  formed in the contacting surface  432  of the traveling nut  430  contacts a segment, a leg, a projection, or the like  476  (terms used interchangeably herein without the intent to limit) formed on the pawl  470  thereby rotating the pawl  470  in the clockwise direction until the head portion  480  of the pawl  470  is aligned with the pocket  500  formed in the non-rotatable shaft  322 . Thereafter, via continued rotation of the traveling nut  430  and the interacting arcuate or curved surfaces between the pawl  470  and the non-rotatable shaft  322 , the head portion  480  of the pawl  470  is received once again within the pocket  500  formed in the non-rotatable shaft  322 . Thus arranged, the bolt  410  is once again rotationally coupled to the non-rotatable shaft  322 . In addition, rotation of the traveling nut  430  and the pawl  470  in the clockwise direction causes the bolt  410 , the spring guide  360 , and the spring  352  to rotate, which preloads the spring  352  once again. 
     More specifically, with continued reference to  FIGS.  16 A- 16 H , the pawl  470  may be pivotably seated in the pocket  500  formed in the non-rotatable shaft  322 . The pawl  470  may include a seat portion  472  for pivotably coupling the pawl  470  relative to the traveling nut  430 , the head portion  480 , and intermediate portion  473  located therebetween. As illustrated, the head portion  480  may have an arcuate or curved outer surface corresponding to the shape of the pocket  500 . The seat portion  472  may serve as the pivot axis of the pawl  470 , which may be substantially parallel to a longitudinal axis or centerline of the rotatable member  50  and/or the external booster  300 . As such, the head portion  480  may be movable between a radially-inward position (e.g., the first or engaged position) and a radially-outward position (e.g., the second or disengaged position). The head portion  480  of the pawl  470  may be arranged and configured to be received within the pocket  500  formed in the non-rotatable shaft  322  to restrain rotation of the bolt  410 . As illustrated, in one embodiment, the head portion  480  may include a proximal face  480   a , a distal face  480   b , and an intermediate face  480   c  extending between the proximal and distal faces  480   a ,  480   b . The proximal and distal faces  480   a ,  480   b  may be arcuate or curved. The intermediate face  480   c  may be arcuate or curved and have a radius. In use, the leg  476  is positioned on a same side of the head portion  480  as the proximal face  480   a  of the head portion  480  and opposite that of the distal face  480   b  of the head portion  480 . 
     As described herein, the external booster  300  is arranged and configured to provide supplemental rotation of the rotatable member  50 , and hence the covering  22 . For example, the external booster  300  may be arranged and configured to provide supplemental rotation to ensure that the covering  22  is moved to an open configuration. Alternatively, the external booster  300  may be arranged and configured to over-rotate the front sheet  30  relative to the rear sheet  34 . 
     That is, according to one or more aspects of the present disclosure, with the external booster  300  in the first configuration, the pawl  470  is in the first or engaged position (e.g., the head portion  480  of the pawl  470  is positioned within the pocket  500  formed in the non-rotatable shaft  322 ). In one embodiment, the head portion  480  of the pawl  470  may extend into the pocket  500  of the non-rotatable shaft  322  and the intermediate face  480   c  may abut or contact an arcuate or curved base wall  502  of the pocket  500 . Thus arranged, the pawl  470  may be rotationally constrained to the non-rotatable shaft  322 , thereby rotationally constraining the bolt  410 . In other words, the external booster  300  may be rotationally constrained in a static, preloaded configuration during a majority of the covering  22  movement. In this configuration, the external booster  300  may not interfere with the operation of the covering  22 . 
     During rotation of the rotatable member  50 , and hence the covering  22 , in the extension direction, with the external booster  300  in the first configuration (e.g., with the spring  352  preloaded and the bolt  410  coupled to the non-rotatable shaft  322 ), the traveling nut  430  rotates in unison with the rotatable member  50  and axially translates along the length of the bolt  410  toward the pawl  470 . As the covering  22  approaches the predetermined extended position (for example, as the covering  22  approaches the extended or deployed position depicted  FIG.  1   ), the contacting surface  432  of the nut  430  approaches the rear surface  474  of the pawl  470 . As the rotatable member  50 , and thus the nut  430 , continue to rotate in the extension direction under the influence of gravity, the pin  475  extending from the rear surface  474  of the pawl  470  approaches and interacts with the pathway  434  formed in the contacting surface  432  of the nut  430 . Continued rotation of the rotatable member  50 , causes the pawl  470  to become disengaged or lifted from the pocket  500  formed in the non-rotatable shaft  322  via the interaction between the pin  475  and pathway  434  thus permitting rotation of the spring guide  360 , the bolt  410 , the nut  430 , and the drive sleeve  450  under the influence of the spring  352 . This additional rotation via the spring  352  enables the covering  22  to extend to the fully deployed position such as, for example, depicted in  FIG.  2   . 
     After the pawl  470  is rotationally disengaged from the non-rotatable shaft  322 , the pawl  470  contacts or engages the abutment surface  512  of the traveling nut  430 . The initial contact or engagement between the pawl  470  and the nut  430  may occur as the rotatable member  50  begins a final or nearly final revolution in the extension direction. Once in contact or engagement, the pawl  470  may rotate the rotatable member  50  in the extension direction to fully extend the covering  22  ( FIG.  2   ). That is, with the pawl  470  disengaged from the non-rotatable shaft  322 , the spring  352  applies a rotation force to cause the spring guide  360 , the bolt  410 , the traveling nut  430 , and the drive sleeve  450  to rotate, which in turns causes the rotatable member  50 , and hence the covering  22 , to rotate in the extension direction. 
     Generally speaking, in use, the external booster  300  may be configured to supplementally rotate the rotatable member  50  any desired rotational amount after the covering  22  reaches a desired extended position, such as a final revolution of the rotatable member  50  associated with a fully extended covering position. That is, as described herein, the external booster  300  may drive or rotate the rotatable member  50  in the extension direction toward an open configuration in which the front and rear sheets  30 ,  34  are laterally spaced from one another and the vanes  38  are substantially horizontal ( FIG.  2   ). In this fully deployed position, a limit stop may inhibit further rotation of the rotatable member  50  under the bias of the spring  352 . As such, in one implementation, the external booster  300  may supplementally rotate the rotatable member  50  once the covering  22  has reached a fully extended, closed position to reconfigure the covering  22  from an extended and closed-vane position (see  FIG.  1   , for example) to an extended and open-vane position (see  FIG.  2   , for example). 
     After rotating the rotatable member  50 , the pawl  470  may be reset into the first or engaged position during normal operation of the architectural-structure covering  10 . For example, during rotation of the rotatable member  50  in the retraction direction, the nut  430  and the pawl  470  may rotate in the opposite direction (e.g., in the clockwise direction as illustrated in  FIGS.  16 A- 16 H ). In addition, the external booster  300 , or at least portions thereof such as, for example, the bolt  410  and the spring guide  360  may rotate in the retraction direction against the bias of the spring  352 , thereby preloading the spring  352 . Once the head portion  480  of the pawl  470  is rotatably aligned with the pocket  500 , the interaction between the corresponding arcuate surfaces causes the pawl  470  to pivot back to its first or engaged position with the head portion  480  located within the pocket  500  of the non-rotatable shaft  322 . In this position, the pawl  470  prevents rotation of the bolt  410 , thereby maintaining the preload in the spring  352  for the next lowering cycle. Upon the pawl  470  moving into the first or engaged position in the pocket  500 , the pawl  470  may not interfere with rotation of the rotatable member  50  and thus further retraction of the covering  22  may occur nominally. As provided herein, the external booster  300  is transitioned back to its first configuration under normal retraction of the covering  22 . 
     In accordance with another separate and distinct aspect of the present disclosure that may be used separately from, or in combination with, the other aspects of an architectural-structure covering disclosed herein, the one or more gears such as, for example, gear  52 ,  332 ,  334  may be in the form of a flexible, compressible, or spring-loaded gear (terms used interchangeably herein without the intent to limit). In use, the one or more flexible gears are arranged and configured to enable compression between adjoining gears to provide, for example, a friction fit type meshing with corresponding gears to ensure constant contact between the gears during operation to prevent, or at least reduce, unwanted backlash and/or unwanted clearance. 
     It should be appreciated that while the flexible gears may be described and illustrated herein in connection with an architectural-structure covering and more particularly for use with coupling the external booster  300  to the rotatable member  50  (as illustrated in  FIGS.  20 A- 20 C ), the flexible gears should not be so limited. That is, the flexible gears may have application outside of architectural-structure coverings and may be used in place of traditional gears. As such, the flexible gears should not be limited for use in architectural-structure coverings unless explicitly claimed. 
     Referring to  FIG.  18   , an example embodiment of a flexible gear  600  is illustrated. As illustrated, in one embodiment, the flexible gear  600  may include an outer circumference  602  having a plurality of teeth  604  for meshing with mating gears as conventionally known. However, in accordance with features of the present disclosure, the flexible gear  600  may also include a plurality of spiral cutouts  610  formed adjacent to the plurality of teeth  604  (e.g., spiral cutouts  610  are positioned between the outer circumference  602  and teeth  604  and center bore or axis of the gear  600 ). In use, the spiral cutouts  610  enable the flexible gear  600  to compress or flex inwardly by a predetermined amount when a radial force is applied to the flexible gear  600 . 
     That is, referring to  FIGS.  19 A and  19 B , and as will be readily appreciated by one of ordinary skill in the art, conventional gears G include a pitch diameter P D .  FIG.  19 A  illustrates a conventional gear G shown in a nominal position with gear teeth/pitch diameters P D  perfectly matching.  FIG.  19 B  illustrates a conventional gear G including a center-to-center offset in the gears G designed and configured to compensate for variances in materials and/or tolerances to avoid interference between corresponding meshed teeth. That is, generally speaking, the pitch diameters P D  of parallel shaft gears G can be determined by measuring the diameter from a center point or distance of the gear G to the circumferentially disposed teeth. Generally speaking, in connection with conventional gears G, the pitch diameters P D  of interconnecting gears G may be designed to exactly mesh ( FIG.  19 A ). More commonly, however, interconnecting gears G may be designed and/or arranged and configured with a slightly reduced pitch diameters P D  and/or offsets to prevent, for example, binding between interconnecting gears G ( FIG.  19 B ). However, one disadvantage with such traditional gears G is that backlash (or slop) between adjacent gears G may be introduced. When used in connection with an architectural-structure covering and, more particularly, when used to couple an external booster to the rotatable member, this unwanted backlash may result in unwanted clearance when the external booster operates to, for example, over-rotate the covering. 
     In contrast, referring to  FIGS.  19 C and  19 D , by utilizing a flexible gear  600 , the pitch diameter P D  between interconnecting gears  600 , G may be designed so that the pitch diameters P D  of the interconnecting gears  600 , G overlap (e.g., the diameter of the flexible gear  600  is arranged and configured to be slightly larger than the actual diameter between the interconnecting gears). For example,  FIG.  19 C  illustrates a flexible gear  600  (although one or more flexible gears  600  could be utilized as needed) incorporating interfering gear teeth/pitch diameters P D  in accordance with one or more features of the present disclosure.  FIG.  19 D  illustrates a flexible gear  600  incorporating an offset center arranged and configured to slightly change or adjust as the flexible gear  600  rotate to compensate for gear roundness error. In use, the gear teeth  602  remain fully engaged to eliminate backlash between gear sets. 
     Thus arranged, in use, when a radially-inwardly directed force C F  is applied to the flexible gear  600  (e.g., by meshing with an adjacent interconnecting gear) the pitch diameter P D  of the flexible gear  600  may compress thereby introducing or creating radially-inwardly directed compression or pressure C F  ( FIG.  20 C ) between intermeshing gears (e.g., intermeshing teeth apply a perpendicular or compression force onto the outer circumference of the flexible gear  600 ). As such, a frictional or compression force between intercoupling meshed gears may be created, which eliminates, or at least reduces, backlash and thus any unwanted clearance. 
     In one embodiment, it is envisioned that the flexible gears  600  may be arranged and configured with 3 to 5-thousandths overlap between adjacent pitch diameters P D . This is in contrast to known, traditional gears G, which may be designed with 3 to 5-thousandths clearance to prevent binding between meshing gears. 
     Referring to  FIG.  18   , in one embodiment, each spiral may include a bump  612  formed thereon. In use, the bump  612  may serve as limit stops to prevent excess deflection of the gear  600  (e.g., bumps  612  could be arranged and configured to bottom out at a certain deflection/gear load). 
     It should be appreciated that while the flexible gears  600  are shown with spiral shaped cutouts  610 , flexibility could be introduced into the gears  600  by any suitable method now known of hereafter developed. For example, alternate shaped cutouts could be utilized such as, for example, slits, circumferential cutouts, etc. Preferably, the cutouts are arranged and configured to provide a substantially uniform pressure around the gear Alternatively, it is envisioned that that flexible gears could be manufactured with alternate materials having different durometers. Combinations of cutouts (e.g., spirals, slits, circumferential cutouts) and material selection (e.g., durometer) in a single flexible gear  600  are also contemplated. 
     The foregoing has many advantages. For instance, as described, the external booster  300  may be automatically actuated or triggered during normal extension of a covering  22  to complete or finish a covering extension operation, which may work against gravitational forces, without requiring additional steps by an operator. Further, the external booster  300  may be automatically reset during normal retraction of the covering  22  from an extended position. Moreover, the external booster  300  may be scalable to accommodate different covering sizes. For instance, the size of the spring (e.g., the length and/or wire diameter) may be varied depending upon the weight of the covering  22 . In addition, and/or alternatively, different rotational limits can be accommodated (e.g., less total rotation could be provided, if desired). For example, in one embodiment, the non-rotatable shaft  322  and pocket  500  could be designed and configured in different relative positions with respect to the traveling nut  430  so that rotation could limit the travel of the booster assembly. For example, the external booster could be arranged and configured to provide a total rotation of 120 degrees or the like, if required for a product. 
     The foregoing description has broad application. While the provided examples describe a silhouette-type covering, it should be appreciated that the concepts disclosed herein may equally apply to any type of covering that may selectively use supplemental energy to actuate, extend, and/or open a covering. For instance, the external booster  300  may be used to actuate operable vanes attached to a support sheet. Further, while the provided examples describe the external booster  300  as assisting in an extension of a covering, the external booster  300  may be configured to assist in raising or retracting a covering. Accordingly, the discussion of any embodiment is meant only to be explanatory and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these embodiments. In other words, while illustrative embodiments of the disclosure have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art. 
     The foregoing discussion has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure are grouped together in one or more aspects, embodiments, or configurations for the purpose of streamlining the disclosure. However, it should be understood that various features of the certain aspects, embodiments, or configurations of the disclosure may be combined in alternate aspects, embodiments, or configurations. Moreover, the following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate embodiment of the present disclosure. 
     The phrases “at least one”, “one or more”, and “and/or”, as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together. 
     As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. 
     Connection references (e.g., engaged, attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative to movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. Identification references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to connote importance or priority, but are used to distinguish one feature from another. The drawings are for purposes of illustration only and the dimensions, positions, order and relative to sizes reflected in the drawings attached hereto may vary. 
     The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof are open-ended expressions and can be used interchangeably herein. 
     All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, back, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are only used for identification purposes to aid the reader&#39;s understanding of the present disclosure, and do not create limitations, particularly as to the position, orientation, or use of this disclosure. 
     While the present disclosure refers to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present disclosure, as defined in the appended claim(s). Accordingly, it is intended that the present disclosure not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof. 
     It should be understood that, as described herein, an “embodiment” (such as illustrated in the accompanying Figures) may refer to an illustrative representation of an environment or article or component in which a disclosed concept or feature may be provided or embodied, or to the representation of a manner in which just the concept or feature may be provided or embodied. However, such illustrated embodiments are to be understood as examples (unless otherwise stated), and other manners of embodying the described concepts or features, such as may be understood by one of ordinary skill in the art upon learning the concepts or features from the present disclosure, are within the scope of the disclosure. In addition, it will be appreciated that while the Figures may show one or more embodiments of concepts or features together in a single embodiment of an environment, article, or component incorporating such concepts or features, such concepts or features are to be understood (unless otherwise specified) as independent of and separate from one another and are shown together for the sake of convenience and without intent to limit to being present or used together. For instance, features illustrated or described as part of one embodiment can be used separately, or with another embodiment to yield a still further embodiment. Thus, it is intended that the present subject matter covers such modifications and variations as come within the scope of the appended claims and their equivalents.