Abstract:
A motorized barrier adjustment apparatus and method includes, in particular, in accordance with one embodiment, motorized barrier adjustment apparatus with a barrier. A controllable motor is connected with the barrier, the controllable motor is conformed to detect motion of the barrier such that movement of the barrier within a predetermined amount activates the motor to move the barrier and where movement of the barrier beyond the predetermined amount does not activate the motor such that the barrier remains where it is moved.

Description:
FIELD OF THE INVENTION 
     This invention relates to a motorized barrier adjustment apparatus and method. In particular, in accordance with one embodiment, the invention relates to a motorized barrier adjustment apparatus including a barrier. A controllable motor is connected with the barrier, the controllable motor conformed to detect motion of the barrier such that movement of the barrier within a predetermined amount activates the motor to move the barrier and where movement of the barrier beyond the predetermined amount does not activate the motor such that the barrier remains where it is moved. In another embodiment, a motorized barrier adjustment apparatus for covering an opening in a structure includes a barrier stored on a barrier storage tube connected with the structure above the opening. A motor is connected with the barrier and a gear reducer is connected with the motor. A controller is connected with the motor where the controller is conformed to detect motion of the barrier such that upon manual movement of the barrier within a predetermined amount the controller activates the motor to move the barrier and where upon manual movement of the barrier beyond the predetermined amount the controller does not activate the motor such that the barrier remains where it is moved. A power source is connected with the controller and the motor where the motor and the gear reducer are contained within the barrier storage tube. 
     BACKGROUND OF THE INVENTION 
     A difficulty arises in the use of protective barriers when a user desires to adjust the location of the barrier. For example only and not by way of limitation, structures with openings, such as buildings with windows, for example, very often include window shades. Normally the window shades are adjustable. They may be raised or lowered manually by means of draw strings and such. They may also be raised or lowered mechanically by use of motors operated by switches or remote controls. It is often difficult to manually raise and lower window shades to their full limits and it can be time consuming as well. Likewise, switch operated motor driven shades are subject to failure and are expensive to install and maintain. 
     By way of example, the prior art known to the Applicants includes devices that do not include cumbersome and dangerous pull cords, to their advantage, but are counterbalanced, manually operated devices only. U.S. Pat. Nos. 6,733,413 to Lagarde et al., 5,133,399 to Hiller et al. and 5,482,100 to Kubar exemplify the state of the art of these types of devices. 
     Other prior art devices include mechanical, motor operated devices that employ switches that can become damaged or deteriorate over time and are costly and time consuming to install such as the drapery actuator disclosed in U.S. Pat. Nos. 5,889,377 and 6,144,177 to Mao or the interconnected switches and sensors used to open and close a flexible curtain rollup door as in U.S. Pat. No. 6,082,433 to Vafaie et al. A serious drawback to these prior art motor operated systems is that, when the motor fails or the power goes out, the system is essentially locked in place. That is, the system must be disassembled and disconnected in order for a user to move the system without power. 
     Another U.S. Pat. No. 5,434,487 to Long et al., discloses a power operating system for a vehicle door for a van that includes a motor operable to power the door open or closed. When a manual movement of the van door a certain distance is detected while the motor is inactive, the motor is energized so as to move the door in the direction of the detected movement to complete the manually initiated door movement. As van doors are required to be either open or shut there is no provision for partial movement to a partially open or partially shut position. That is, Long et al. provides that any manual movement beyond a certain amount will activate a motor to power the door fully open or fully closed. Another U.S. Pat. No. 7,417,397 to Berman et al., discloses an automated shade system that uses software to monitor solar penetration and heat gain and such and to adjust shades as needed to control interior lighting and temperature. 
     Thus, while both manually operated and motorized devices are known, there is a need in the art for a simple, easy to install, easy to use and easy to maintain apparatus and method for a combination manual and motorized barrier adjustment device. It therefore is an object of this invention to provide a motorized barrier adjustment device that has no expensive switches and that can be operated manually and by motor to enable a user to exactly position a window barrier in any desired location along a window, for example only. 
     SUMMARY OF THE INVENTION 
     Accordingly, the motorized barrier adjustment apparatus of the present invention, according to one embodiment, includes a barrier. A controllable motor is connected with the barrier, the controllable motor is conformed to detect motion of the barrier in the normal direction of travel such that movement of the barrier within a predetermined amount activates the motor to move the barrier and where movement of the barrier beyond the predetermined amount does not activate the motor such that the barrier remains where it is moved. 
     As used herein, the term “barrier” includes its common meaning and is given its ordinary definition. By way of example only, the barrier of the present invention includes covering for openings in structures. In particular, but not by way of limitation, a barrier of the present invention includes a window shade for use in covering a window in a structure, such as a residential or commercial building. Obviously, any type of barrier may be accommodated. A pliable, resiliently flexible material such as described in co-pending U.S. patent application Ser. No. 11/190,144 is preferred but, again, any type of barrier now known or hereafter developed is suitable. 
     According to other aspects of this invention, a counterbalance is connected with the barrier and the controllable motor can be back driven. As used herein, the term “back driven” is used in its common manner. That is, it describes a motor that is capable of rotating in either direction. By contrast, motors that are not capable of being back driven are essentially locked in position when power is not present. Applicant&#39;s back driven motor can be moved safely without power in either direction thus preventing the need to disassemble the system in the event no power is available. 
     In another aspect, the predetermined amount is selected from a group including: time and distance. In one aspect, the predetermined amount of time is approximately one second and the predetermined amount of distance is approximately one inch. In a further aspect, an extension rod is connected with the barrier. In a further aspect, the extension rod is connected with the barrier with a bias so that it is easy to grip and is hinged to allow it to fold out of the way. 
     In one aspect, the controllable motor moves the barrier a maximum amount in the direction of initial movement of the barrier. In another aspect, the barrier surrounds a barrier storage tube and the controllable motor is contained within the barrier storage tube. In a further aspect, many barriers and controllable motors connected with each other such that movement of one barrier results in proportionally identical movement of the other barriers. 
     According to another embodiment of the invention, a motorized barrier adjustment apparatus for covering an opening in a structure includes a barrier stored on a barrier storage tube connected with the structure above the opening. A motor is connected with the barrier. A gear reducer and a controller are connected with the motor where the controller is conformed to detect motion of the barrier such that upon manual movement of the barrier within a predetermined amount the controller activates the motor to move the barrier and where upon manual movement of the barrier beyond the predetermined amount the controller does not activate the motor such that the barrier remains where it is moved. A power source is connected with the controller and the motor and the motor and the gear reducer are contained within the barrier storage tube. 
     In another aspect of the invention, a counterbalance is connected with the barrier and the motor can be back driven. In a further aspect, the predetermined amount is selected from a group including: time and distance. In another aspect, the controller stores time counts and distance counts. In one aspect, the time counts are produced by a clock in the controller. In another aspect, the distance counts are generated by commutator pulses from the motor. In a further aspect, many barriers are connected with each other such that movement of one barrier results in proportionally identical movement of the remaining barriers. 
     In accordance with another embodiment of the invention, a motorized barrier adjustment method for covering an opening in a structure includes the steps of providing a barrier stored on a barrier storage tube connected with the structure above the opening with a motor connected with the barrier, a gear reducer connected with the motor, a controller connected with the motor where the controller is conformed to detect motion of the barrier such that upon movement of the barrier within a predetermined amount the controller activates the motor to move the barrier and where upon movement of the barrier beyond a predetermined amount the controller does not activate the motor such that the barrier remains where it is moved and a power source connected with the controller and the motor where the barrier, the motor and the gear reducer are contained within the barrier storage tube; and moving the barrier within the predetermined amount. 
     According to another aspect of the invention the method includes the step of not moving the barrier within the predetermined amount and instead moving the barrier beyond the predetermined amount. In another aspect, a counterbalance is connected with the barrier and the motor can be back driven. In a further aspect, the method includes connecting many barriers with each other such that movement of one barrier results in proportionally identical movement of the remaining plurality of barriers; and moving one of the bathers. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Other objects, features and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiment, the appended claims and the accompanying drawings in which: 
         FIG. 1  is a perspective partial cut away view of the motorized barrier adjustment apparatus according to one embodiment; 
         FIG. 2  is a front view of the invention of  FIG. 1  with the barrier in a partially down position; 
         FIG. 3  is a front perspective view of the invention of  FIG. 1  with the barrier near the lower limit and covering the window and the extension rod folding away; 
         FIG. 4  is an enlarged front view from  FIG. 3  showing the position of the extension rod when the barrier is at the lower limit; 
         FIG. 5  is an operation flowchart of the invention of  FIG. 1 ; 
         FIG. 6  is a profiling/set up chart of the invention of  FIG. 1 ; and 
         FIG. 7  is a diagram of the impulse logic from the motor of the invention of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The preferred embodiment of the present invention is illustrated by way of example in  FIGS. 1-7 . With specific reference to  FIGS. 1 and 2 , the motorized barrier adjustment apparatus  10  according to a preferred embodiment, includes a barrier  12 . Barrier  12  preferably essentially surrounds and is wrapped or wound around barrier storage tube  14 . Located within barrier storage tube  14  are motor  16  and gear reducer  18 . A motor controller  20  is provided. A power supply  22 , such as batteries for example, is connected with motor  16  and motor controller  20  all as will be more fully described hereafter. Needless to say, power supply  22  may be any type of power source now known or hereafter developed for providing local power to the apparatus. According to a preferred embodiment, motorized barrier adjustment apparatus  10  is used with structures  24 , such as a residential or commercial building, for example only, with openings  26 , such as windows, with side jambs  28  and a top  30  of the opening  26  and a bottom  32  again for example only. Opening  26  is typically sealed with glass  34  or glazing of some sort. As illustrated therefore, preferably, motorized barrier adjustment apparatus  10  is connected with the structure  24  on the inside of the structure  24  at the top  30  of the opening  26  and in front of the glass  34 . 
       FIG. 1  also illustrates counterbalance  36  also located within barrier storage tube  14 . Counterbalance  36  is any type of counterbalance, such as a torsion spring, now known or hereafter developed.  FIG. 2  also illustrates extension rod  38 . Extension rod  38  is connected with barrier  12  at a bias as illustrated. That is, extension rod  38  is biased to extend away from side jamb  28  to allow sufficient room for a user to grip the extension rod  38  quickly and easily. Extension rod  38  enables a user to manually move barrier  12  even when barrier  12  is in the fully up position shown in  FIG. 1  and at the upper limit of the travel of barrier  12 . Additionally, extension rod  38  is connected by hinge  40  with barrier  12 . Hinge  40  functions to allow extension rod  38  to swivel or rotate upon contact with the bottom  32  of opening  26  as will be discussed more fully with regard to  FIGS. 3 and 4 . Hinge  40  is any type of hinge device now known or hereafter developed. Importantly, extension rod  38  includes a beveled tip  42  that aides in the rotation of extension rod  38  by creating a rounded, beveled “slippery surface” contact area. 
       FIG. 2  also illustrates upper cover  44  used as a cosmetic shield of the apparatus when in the fully raised position. Further, bottom bar  46  is connected with the barrier  12 . Bottom bar  46  adds weight and rigidity to the leading end of barrier  12 . Bottom bar  46  may be attached to the back of barrier  12  or sewn between layers of barrier  12  and thus be kept from direct observation 
     Referring now to  FIGS. 3 and 4 , motorized barrier adjustment apparatus  10  is shown near its lower limit position in  FIG. 3  and at its lower limit in  FIG. 4 . In  FIG. 3 , bottom bar  46  is near the bottom  32  of opening  26  and the combination of the beveled tip  42  of extension rod  38  and hinge  40  cause extension rod  38  to begin to fold itself parallel to the bottom  32  and behind bottom bar  46  and barrier  12 .  FIG. 3  also shows an aspect of the invention including a central flexible hinge  39  in the middle of extension rod  38 . Flexible hinge  39  essentially divides extension rod  38  into two rigid sections on either side of hinge  39 . Hinge  39  facilitates the folding of extension rod  39  from a vertical position to a horizontal position. Thus, as shown in  FIG. 4 , extension rod  38  (shown in dashed lines) is efficiently directed from a vertical hanging position to a horizontal position that is hidden from view when the barrier  12  is at its lower limit.  FIG. 4  also shows bottom bar  46  in dashed lines indicating that it is connected behind or between barrier  12 , as mentioned above, so that it is not visible. 
     Referring now to  FIG. 5 , the operation of the motorized barrier adjustment apparatus  10  is disclosed. Applicants have created a system that is divided into two operations, the first is for systems that include counterbalances  36  and motors  20  that can be back driven. The second is for systems that include motors  20  that can not be back driven. 
     Going to  FIG. 5  starting at step  101  for systems that can be back driven, to initiate movement of the barrier  12  the user can move the barrier  12  either up or down at step  102 . This wakes up the motor controller  20  at step  103  and starts the time and distance counts. At step  104  a determination is made whether the distance or time was less than a predetermined amount, if the answer was yes the process moves to step  110  starts the motor  16  and moves the barrier  12  in the direction of the initial movement to the profile stored in the motor controller  20 . Once the limit is reached the motor  16  is stopped at step  109  and at step  108  the timer times out and the process goes to sleep. If, however, at step  104  the movement of the barrier  12  is greater than the predetermined distance or time the process moves to step  105  and the motor controller  20  does not start the motor  16  and counts the distance and time of the new position of the barrier  12  then moves to step  106 . In step  107  the timer times out and the motor controller  20  goes to sleep. 
     At step  101 , if the system is not counterbalanced and the motor  16  and the gear reducer  18  can not be back driven then the process goes to step  111  where the barrier  12  can only be moved in the downward direction. At step  112  the motor controller  20  is awakened and starts a distance and time count. At step  113  the motor controller  20  determines if the distance or time counts are less than a predetermined amount and, if they are, the process moves to step  119  starts the motor  16  and moves the barrier  12  to the upper limit then stops the barrier  12  at step  118 . At step  117  the timer times out and the motor controller  20  goes to sleep. 
     At step  113 , if the count of time or distance is greater than the predetermined amount the process moves to step  114  where the motor controller  20  does not run the motor but the time and distance count are recorded and the barrier  12  stays in the new position. Once the barrier  12  stops at step  115 , the process moves to step  116  where the timer times out and the motor controller  20  goes to sleep. With either drive system, the auto height adjustment will function in the same manner. 
     Referring next to  FIG. 7 , the profile sequence is discussed. Beginning in step  51 , the motor controller  20  determines whether the barrier  12  can be back driven. It then moves to step  59  which allows an energized device  10  to be re-profiled. In step  60  the barrier  12  can be moved either up or down within a predetermined period of time, such as one second, or within a predetermined distance, such as one inch. If the barrier  12  has not moved, the program moves to step  58 . If the barrier  12  has moved, the process moves to step  54  and the motor  16  starts and moves the barrier  12  to its upper limit determined by either a stall induced by the manner of the connection of the apparatus with the structure  24  or a physical stall by the user and the top limit is recorded in the motor controller  20 . The process then goes to step  55 , zeros the distance count and starts the down limit timer. At step  56  the user manually moves the barrier  12  to its lower limit and at step  57 , the down timer times out, the motor controller  20  sets the lower travel limit, stores the new profile, and puts the electronics to sleep at step  58 . After a loss of power or reset condition, such as pushing the reset, installing, or replacing batteries, the motor controller  20  will clear the profile stored in memory at step  61  and the operational upper limit operation cannot be carried out until a manual “profile” operation is complete. The motor controller  20  must re-establish its position by finding the top or upper limit of travel. For safety reasons, is undesirable for the motor controller  20  to start moving the barrier  12  as soon as power is restored. Once the travel limits are established, and a profile is stored, the apparatus  10  is placed in the normal operation mode and may be either operated manually or in “semi-automated” mode. 
     At step  51 , in the case of an apparatus  10  that will not allow the motor  16  to be back driven, the system is energized by installing or replacing power supply  22 , such as batteries, or pressing the reset button at step  52 . Then the user then pulls the barrier  12  downward, using extension rod  38  if needed, which wakes up the electronics at step  53  and the process moves to step  54  then completes the process outlined above. Obviously, the controls can be set by the user to alter the limits inside the stall limit range. Doing so will prolong the power supply  22 , battery, life as well as reduce the stress on the motor  16  and other drive components. 
     Quadrature encoders are known in the art and can provide direction of rotation as well as counting pulses for position determination. Obviously, sensing of manual movement of motor  16  can be accomplished in any of a number of ways as with both a comparator and with an opto-coupler. Motor controller  20  is a programmable controller known in the art that is connected electronically with motor  16  so as to detect manual movement of unenergized motor  16 . For the purposes of conserving energy, this invention preferably uses a standard brush type direct current (DC) motor  16  which provides the electromotive force and a generator function. It does not need to remain under power at all times. When the barrier  12  is moved, the motor  16  connected to the barrier  12  rotates and the impulses from the motor  16  are sensed by the microprocessor software in motor controller  20  to determine both direction of rotation and angle of rotation via, for example only, brush commutations. A standard comparator circuit, for example, determines the polarity of the “motor+” and “motor−” poles providing clockwise or counterclockwise input. The comparator triggers the motor controller  20  to “wake up” and begin direction counting. The second circuit senses the brush commutations for the motor controller  20  position counting. This provides both the motor force to move the barrier  12  as well as the input to the motor controller  20  to determine barrier  12  position and direction. 
     Referring now to  FIG. 7 , the pulse counts are diagramed to describe their function. The two pulses  48  and  50  are phased where pulse count  1  reads the high of both pulses followed by pulse count  2  that reads the high of pulse  48  and the low of pulse  50 . Next the pulse count  3  reads the low of both pulses and pulse count  4  reads the low of pulse  48  and the high of pulse  50  then the pulse counts repeat themselves. With this method the motor controller  20  determines direction of movement as well as time and distance. 
     By way of continued explanation, in a preferred embodiment, motorized barrier adjustment apparatus  10  includes protective barrier  12  mounted on the interior side of the glazing  34  rather than the exterior. The interior mounted barrier  12  does not necessarily include a mechanical locking feature incorporated into the bottom bar  46  of the barrier  12  and the bottom  32  sill portion of the frame of opening  26 . However, it does provide a locked and unlocked state by design. The system has a motor  16  and gear reducer  18  with lower torque output resulting from a gear box design with a more efficient, less reduction, and slower turning electric permanent magnet direct current (PMDC) motor. When moving the barrier  12  there is parasitic drag from the motor  16 , the gear reducer  18 , the weight of the barrier  12 , and the inertia of the barrier storage tube assembly  14 . This parasitic drag can be counterbalanced to provide for a system that can be manually moved with the motor  16  and the gear reducer  18  always connected to the barrier storage tube  14 . With proper counterbalancing achieved, in the preferred embodiment a torsion spring  36  is used, any manual movement of the barrier  12  in either the upward or downward direction causes the barrier storage tube  14  to turn thereby “waking up” the electronics in the motor controller  20 . These factors combined with the ability to “wake up” the motor controller  20  on a manual movement of the barrier  12 , which is detected electronically as described above, produces an operational mode that could be referred to as “semi-automated”. In this semi-automated mode the user can manually start the movement of the barrier  12 . With a pull in the downward direction of the barrier  12  to indicate to the motor controller  20  that a move to the closed position is desired or a push upward of the barrier  12  in the upward direction to indicate that a move to the open position is desired. This is determined through the first initial movement of the barrier  12  and can be timed for a predetermined period of time, such as one second, or determined if the distance the barrier  12  has traveled is less than a predetermined distance, such as 1 inch, the motor controller  20  will wake up, start the motor  16  and power the barrier  12  to its limit position, in the direction of the initial movement, shut down, and put the motor controller  20  back to sleep. 
     Alternately, the user can carry out a complete manual positioning of the barrier  12 , provided they manually move the barrier  12  for a time period greater than the predetermined time period or displace the barrier  12  by a distance greater than the predetermined distance outside the region of automatic movement, referred to as the predetermine time or distance. In this manual operation, the barrier  12  can be manually moved to a new position without the motor controller  20  starting the motor  16  and the barrier  12  remains in that new position with the motor controller  20  still asleep. However, if the user desires to move the barrier  12  to a position that is inside the predetermined time or distance, the user must first manually move the barrier  12  outside the predetermined time or distance and then move it back to the desired position. 
     Another embodiment of the invention includes co-ordination of multiple motorized barrier adjustment apparatus  10 . That is, this invention can be used on multiple bathers  12   n  of multiple heights, that is for windows of varying dimensions, when used with Zwave technology incorporating the features of Applicants&#39; co-pending application for a Method of Wiring Devices in a Structure Using a Wireless Mesh Network. That is, by means of electronic connection, the motor controller  20  of one particular barrier  12  being adjusted becomes the master motor controller  20  and sends a position signal to the remaining “slave” barriers  12   n  in the group. If the user desires an “all-move” or “group-move” then a “trigger event” prior to, or following the manual positioning of the barrier  12  is required. Following such an action all ‘grouped’ units would then move their barriers  12  to the same position, such as a percentage of ‘openness’ (100%=open 0%=closed) as the “master unit” has established. The trigger event can, for example only, consist of some manual excursion of the barrier  12  in the opposite direction of the direction in which the user intends the final position of the barriers  12 ; plural because the intention is an “all-move” or “group-move”. It is important to note that this method of movement is similar to a master slave arrangement but the relationship is dynamic in that any protective barrier  12  can become the master or a slave depending on the protective barrier  12  being adjusted. Said another way, the user can move any one of the protective barriers  12  in a group to either an upper limit, a lower limit, or anywhere in between the two limits and with a short tug on the protective barrier  12  being adjusted the remaining protective barriers  12  in the group communicate with the “now adjusted” protective barrier  12  and power up to move to the “same” relative height. 
     Still further, attached to the bottom of the barrier  12  is an extension rod  38  seen in  FIGS. 2-4 . The first end on the extension rod  38  is pivotally attached to the bottom bar  46  or barrier  12  and is designed to be biased away from the vertical jamb  28  such that it is convenient for the user to get their hand around and grab the extension rod  38 . This biasing also facilitates the collapsing of the extension rod  38  as it contacts the sill area at the bottom  32  of opening  26 . Additionally the second end of the extension rod  38  includes beveled tip  42  to further assist in the collapsing such that when the protective barrier  12  is fully closed, as shown in  FIGS. 3 and 4 , the extension rod  38  is no longer visible. 
     Preferably, a motor  16  connected to barrier storage tube  14  without a gear reduction system  18  can easily be rotated in either direction. As the desire for more compact motors emerge, the need for gear reduction increases. Gear efficiencies also are important in the differences between the amounts of power input to the amount of power output. Further if one is trying to achieve the most efficient condition, one must counterbalance the weight of the barrier  12  such that the motor  16  is only required to produce the energy needed to overcome inertia and move the barrier  12 . In this most efficient condition, movement of the barrier  12  can turn the motor  16  allowing manual adjustment of the barrier  12  without the use of the motor  16  or the need to disconnect the motor  16  from the barrier storage tube  14 . 
     In broadest terms, an object of the invention is a counterbalanced protective barrier system that automatically moves a protective barrier or covering to its upper limit when manually moved less than a predetermined amount in the upward direction and moves the protective barrier or covering to its lower limit when manually moved less than a predetermined amount in the downward direction. When the protective barrier or covering is manually moved an amount greater that the predetermined amount in either direction the covering will remain in the new position established by the manual movement. The system also includes an extension rod to assist in reaching the covering to initiate movement when the covering is normally out of reach. The extension rod collapses out of sight when the cover is closed and is biased to extend away from the jamb with sufficient room to allow one to grip the extension rod. Further, protective barriers may be electronically grouped together through a mesh network, such as a Zwave controlled network, so that they can automatically adjust their height based on the height of one protective barrier in the group, as more particularly described in co-pending U.S. patent application for a Control for Positioning Multiple Barriers Apparatus and Method filed this same day. 
     In particular, the motorized barrier adjustment apparatus and method of the present invention does not require externally or internally accessible switches. A user can either manually move the protective barrier  12  less than a predetermined distance and the motor  16  engages to drive the protective barrier  12  to the full extent of travel in the direction of movement or the user can move the protective barrier  12  past the predetermine distance and to the desired location where the barrier will remain as placed  12 . Extension rod  38  provides a noticeable function without being noticed when the barrier  12  is in the closed position. Further, an “auto height adjustment” feature as described herein determines if the protective barriers  12  in a group are above or below the target protective barrier  12  and then adjusts them all so that they all are in the same relative position. If the user needs to move the protective barrier  12  a distance location inside the predetermined distance, they simply first move the protective barrier  12  outside the predetermined distance and then back to the desired location where the barrier  12  will remain as placed. 
     The description of the present embodiments of the invention has been presented for purposes of illustration, but is not intended to be exhaustive or to limit the invention to the form disclosed. The invention, for example only, is not limited to window coverings. The invention is applicable in a wide variety of uses such as in pull down projector screens and or similar devices, for example. Thus, many modifications and variations will be apparent to those of ordinary skill in the art. As such, while the present invention has been disclosed in connection with an embodiment thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention as defined by the following claims.