Patent Publication Number: US-2022228650-A1

Title: Actuator system and segmented pulley transmission including the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/845,389 filed on May 9, 2019, and titled ACTUATOR SYSTEM AND SEGMENTED PULLEY TRANSMISSION INCLUDING THE SAME, the entirety of which is incorporated herein by reference. 
    
    
     FIELD 
     The subject disclosure generally relates to transmissions, and more particularly to an actuator system for a segmented pulley and to a segmented pulley transmission including the same. 
     BACKGROUND 
     Transmissions are well known and can be used to change the ratio between rotating elements in a power train. Potential applications for transmissions are numerous and include motor vehicles, human-powered vehicles, maritime craft and heavy machinery, such as pumps, turbines, mixers, winches, centrifuges and shredders. 
     Clutchless multi-ratio transmissions allow the ratio between rotating elements to be changed while the transmission is under load. Certain mechanical problems can affect clutchless multi-ratio transmissions that limit their widespread utilization; specifically, the ability of such transmission systems to function at high speeds or under significant loads effectively and efficiently in practical applications. In addition, ratcheting, slippage, and tensioning problems can limit the commercial viability of such transmissions by decreasing their reliability, decreasing their efficiency and increasing wear. Accordingly, segmented pulley transmissions have been developed to reduce or alleviate at least some of these mechanical problems. 
     For example, U.S. Pat. No. 8,753,236 to Wong et al. discloses a segmented pulley transmission, wherein a pulley assembly is mounted on an axle. The pulley assembly includes a core pulley having a first set of mating features on a peripheral surface thereof and a pulley segment set that comprises a number of pulley segments slidably mounted in the pulley assembly and arranged in a ring concentric with the core pulley. The pulley segments are individually actuatable into and out of the pulley assembly. The pulley segments have a second set of mating features on a peripheral surface matching the first set of mating features. An endless drive member has corresponding mating features on an inside surface for engaging the first and second sets of mating features of the core pulley and the pulley segments in an engaging position. Contact between the endless drive member and the core pulley defines a contact zone. An actuator actuates the pulley segments between the engaging and non-engaging positions when the pulley segments are outside of the contact zone. 
     U.S. Pat. No. 9,816,598 to Wong discloses a key pulley segment for a segmented pulley transmission that is either first or last in a pulley segment set to engage an endless member. The first or last key segment teeth to engage or disengage the endless member, respectively, are shortened or completely trimmed, and the adjacent pulley segment to the key segment is elongated such that a portion of the tooth profile extends toward the key segment. The shortened tooth or teeth and elongated adjacent segment together allow for many pulley segments to be designed as key segments. Completely trimmed teeth may be engineered to create a supporting surface for the endless member on the key segment. The elongated adjacent segment may have an extending portion which slidably mates with the supporting surface of the key segment, thereby receiving radial support therefrom. Multiple pulley segments from different pulley segment sets may be connected or constructed to move together in a unified stack. Unified stacks may be moved by way of a cam or roller-cam system. Chassis-mounted cams engage the rollers outside of the contact zone and, via roller-a 
       1  actuator system for moving a plurality of pulley segments of a segmented pulley and a novel segmented pulley transmission for rotatably coupling a first rotatable member and a second rotatable member in a power train. pulley assembly and arranged in a ring concentric with the core pulley. The pulley segments are individually actuatable into and out of the pulley assembly. The pulley segments have a second set of mating features on a peripheral surface thatching the first set of mating features. An endless drive member has corresponding mating features on an inside surface for engaging the first and second sets of mating features of the core pulley and the pulley segments in an engaging position. Contact between the endless drive member and the core pulley defines a contact zone. An actuator actuates the pulley segments between the engaging and non-engaging positions when the pulley segments are outside of the contact zone. 
     U.S. Pat. No. 9,816,598 to Wong discloses a key pulley segment for a segmented pulley transmission that is either first or last in a pulley segment set to engage an endless member. The first or last key segment teeth to engage or disengage the endless member. respectively, are shortened or completely trimmed, and the adjacent pulley segment to the key segment is elongated such that a portion of the tooth profile extends toward the key segment. The shortened tooth or teeth and elongated adjacent segment together allow for many pulley segments to be designed as key segments. Completely trimmed teeth may be engineered to create a supporting surface for the endless member on the key segment. The elongated adjacent segment may have an extending portion which slidably mates with the supporting surface of the key segment, thereby receiving radial support therefrom. Multiple pulley segments from different pulley segment sets may be connected or constructed to move together in a unified stack. Unified stacks may be moved by way of a cam or roller-cam system. Chassis-mounted cams engage the rollers outside of the contact zone and, via roller-arms, individual segments of a unified&#39;stack are moved into or out of engagement. Rollers may be actuated into and out of engagement with the cams by electromagnets, fixable mounted in an array. 
     While the contributions of known segmented pulley transmissions are laudable, improvements and/or alternatives are generally desired. It is therefore an object to provide a novel actuator system for moving a plurality of pulley segments of a segmented pulley and a novel segmented pulley transmission for rotatably coupling a first rotatable member and a second rotatable member in a power train. 
     SUMMARY 
     It should be appreciated that this summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description of embodiments. This summary is not intended to be used to limit the scope of the claimed subject matter. 
     Accordingly, in one aspect there is provided an actuator system for moving a plurality of pulley segments of a segmented pulley between an engaged region and a disengaged region, the actuator system comprising: a deflector configured to rotate at least between a first position and a second position; and a plurality of followers, each of the followers comprising a protrusion configured to engage the deflector to move the respective one of the pulley segments between the engaged region and the disengaged region, wherein the deflector is configured to move between the first position and the second position to selectively engage the plurality of followers and direct each of the followers between an engaged position and a disengaged position, to move the plurality of pulley segments between the engaged region and the disengaged region. 
     In one or more embodiment, each of the followers further comprises a body for securing the follower to the respective one of the pulley segments, and the protrusion extends from the body. In one or more other embodiments, each of the followers is integrally formed with the respective one of the pulley segments, and the protrusion extends directly from the respective one of the pulley segments. 
     In one or more embodiments, the deflector may be configured to rotate about a generally radial axis of the segmented pulley. 
     In one or more embodiments, the deflector may define at least one cam surface for engaging the protrusion. The at least one cam surface may comprise an engaging cam surface and a disengaging cam surface, wherein the engaging cam surface is configured to contact the protrusions of the plurality of followers and direct each of the followers from the disengaged position and the engaged position, and wherein the disengaging cam surface is configured to contact the protrusions of the plurality of followers and direct each of the followers from the engaged position to the disengaged position. 
     In one or more embodiments, the deflector may be further configured to rotate to a neutral position where the deflector will not engage the plurality of followers during rotation of the segmented pulley. The neutral position may be located between the first position and the second position. 
     In one or more embodiments, the deflector may comprise an elongate body extending between a root and a distal tip, and the deflector may be configured to rotate at the root, such that the distal tip moves in a generally axial direction of the segmented pulley. 
     In one or more embodiments, the protrusion may extend in a generally radial direction of the segmented pulley and may be axially offset from an outer peripheral surface of the segmented pulley. The protrusion may be a roller that is configured to engage the deflector by rolling along the deflector. 
     In one or more embodiments, the actuator system may further comprise an electromagnetic actuator for rotating the deflector between at least the first position and the second position. The electromagnetic actuator may comprise at least one solenoid. 
     According to another aspect, there is provided a segmented pulley transmission for rotationally coupling a first rotatable member and a second rotatable member, the segmented pulley transmission comprising: a first pulley assembly for coupling to the first rotatable member, the first pulley assembly comprising a first pulley and a second pulley concentric with the first pulley, the second pulley being a segmented pulley having a plurality of pulley segments that are individually moveable between an engaged region and a disengaged region; a second pulley assembly for coupling to the second rotatable member and spaced apart from the first pulley assembly; an endless member engaging the first pulley assembly and the second pulley assembly and extending therebetween, to rotationally couple the first pulley assembly and the second pulley assembly; and an actuator system as defined in any of the above paragraphs of this Summary and coupled to the plurality of pulley segments of the second pulley for selectively moving the plurality of pulley segments between the engaged region and the disengaged region. 
     In one or more embodiments, the actuator system may further comprise an idler pulley for engaging the endless member and configured to adjust slack in the endless member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments will now be described more fully with reference to the accompanying drawings, in which: 
         FIGS. 1 a  and 1 b    are simplified side and axonometric views, respectively, of a segmented pulley transmission with an actuator system having a deflector in a first position; 
         FIGS. 2 a  and 2 b    are simplified side and axonometric views, respectively, of the segmented pulley transmission of  FIGS. 1 a  and 1 b   , with the deflector in a neutral position; 
         FIGS. 3 a  and 3 b    are simplified side and axonometric views, respectively, of the segmented pulley transmission of  FIGS. 1 a  and 1 b   , with the deflector in a second position; 
         FIGS. 4 a  and 4 b    are simplified side and axonometric views, respectively, of the segmented pulley transmission of  FIGS. 1 a  and 1 b   , showing the actuator system transitioning a pulley segment from an engaged region to a disengaged region; 
         FIGS. 5 a  and 5 b    are simplified side and axonometric views, respectively, of the segmented pulley transmission of  FIGS. 1 a  and 1 b   , showing the transitioned pulley segment of  FIGS. 4 a  and 4 b    in the disengaged region; and 
         FIG. 6  is an axonometric view of the segmented pulley transmission of  FIG. 1 a  and 1 b   , with a portion of the external housing omitted. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The foregoing summary, as well as the following detailed description of certain embodiments will be better understood when read in conjunction with the accompanying drawings. As used herein, an element or feature recited in the singular and preceded by the word “a” or “an” should be understood as not necessarily excluding a plural of the elements or features. Further, references to “one example” or “one embodiment” are not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the recited elements or features of that one example or one embodiment. Moreover, unless explicitly stated to the contrary, examples or embodiments “comprising,” “having” or “including” an element or feature or a plurality of elements or features having a particular property may further include additional elements or features not having that particula lso, it will be appreciated that the terms “comprises,” “has” and “includes” mean “including but not limited to” and the terms “comprising,” “having” and “including” have equivalent meanings. 
     As used herein, the term “and/or” can include any and all combinations of one or more of the associated listed elements or features. 
       FIGS. 1 a  and 1 b    are simplified side and axonometric views, respectively, of a segmented pulley transmission with an actuator system having a deflector in a first position; 
       FIGS. 2 a  and 2 b    are simplified side and axonometric views, respectively, of the segmented pulley transmission of  FIGS. 1 a  and 1 b   , with the deflector in a neutral position; 
       FIGS. 3 a  and 3 b    are simplified side and axonometric views, respectively, of the segmented pulley transmission of  FIGS. 1 a  and 1 b   , with the deflector in a second position; 
       FIGS. 4 a  and 4 b    are simplified side and axonometric views, respectively, of the segmented pulley transmission of  FIGS. 1 a  and 1 b   , showing the actuator system transitioning a pulley segment from an engaged region to a disengaged region; 
       FIGS. 5 a  and 5 b    are simplified side and axonometric views, respectively, of the segmented pulley transmission of  FIGS. 1 a  and 1 b   , showing the transitioned pulley segment of  FIGS. 4 a  and 4 b    in the disengaged region; and 
       FIG. 6  is an axonometric view of the segmented pulley transmission of  FIG. 1 a  and 1 b   , with a portion of the external housing omitted. 
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The foregoing summary, as well as the following detailed description of certain embodiments will be better understood when read in conjunction with the accompanying drawings. As used herein, an element or feature recited in the singular and preceded by the word “a” or “an” should be understood as not necessarily excluding a plural of the elements or features, Further, references to “one example” or “one embodiment” are not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the recited elements or features of that one example or one embodiment. Moreover, unless explicitly stated to the contrary, examples or embodiments “comprising,” “having” or “including” an element or feature or a plurality of elements or features having a particular property may further include additional elements or features not having that particular property. Also, it will he appreciated that the terms “comprises,” “has” and “includes” mean “including but not limited to” and the terms “comprising,” “having” and “including” have equivalent meanings. 
     As used herein, the term “and/or” can include any and all combinations of one or more of the associated listed elements&#39;or features. 
     It will be understood that when an element or feature is referred to as being “on,” “attached” to, “connected” to, “coupled” with, “engaged” with, “contacting,” etc. another element or feature, that element or feature can be directly on, attached to, connected to, coupled with or contacting the other element or feature or intervening elements may also be present. In contrast, when an element or feature is referred to as being, for example, “directly on,” “directly attached” to, “directly connected” to, “directly coupled” with, “directly engaged” with or “directly contacting” another element of feature, there are no intervening elements or features present. Additionally, when an element or feature is referred to as being “attached” to, “connected” to, “coupled” with, “engaged” with, “contacting,” etc. another element or feature, it should be understood as not necessarily excluding further elements or features being attached to, connected to, couple with, engaged with, contacting, etc. those same elements or features. For example, in some instances, elements may be coupled in a one-to-one relationship; in other instances, a single element may be coupled to a plurality of other elements, or vice versa. 
     It will be understood that spatially relative terms, such as “under,” “below,” “lower,” “over,” “above,” “upper,” “front,” “back” and the like, may be used herein for ease of describing the relationship of an element or feature to another element or feature as depicted in the figures. The spatially relative terms can however, encompass different orientations in use or operation in addition to the orientation depicted in the figures. 
     Reference herein to “example” means that one or more feature, structure, element, component, characteristic and/or operational step described in connection with the example is included in at least one embodiment and/or implementation of the subject matter according to the subject disclosure. Thus, the phrases “an example,” “another example,” and similar language throughout the subject disclosure may, but do not necessarily, refer to the same example. Further, the subject matter characterizing any one example may, but does not necessarily, include the subject matter characterizing any other example. 
     Reference herein to “configured” denotes an actual state of configuration that fundamentally ties the element or feature to the physical characteristics of the element or feature preceding the phrase “configured to.” 
     Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of a lower-n /or a higher-numbered item (e.g., a “third” item). 
     As used herein, the terms “approximately” and “about” represent an amount close to the stated amount that still performs the desired function or achieves the desired result. For example, the terms “approximately” and “about” may refer to an amount that is within engineering tolerances that would be readily appreciated by a person skilled in the art. 
       FIG. 6  shows a segmented pulley transmission, generally identified by reference character  120 . As will be appreciated, a portion of an external housing of the segmented pulley transmission  120  has been omitted in  FIG. 6  to view the interior.  FIGS. 1 a  and 1 b    also show the segmented pulley transmission  120  and have been simplified to facilitate understanding of this description and certain elements of the segmented pulley transmission  120  have been omitted, such as the external housing. In some embodiments, the segmented pulley transmission  120  may include elements such as those shown and described in PCT International Application No. PCT/CA2018/051475 filed on Nov. 20, 2018, and titled PULLEY ASSEMBLY FOR A SEGMENTED PULLEY TRANSMISSION AND ACTUATOR SYSTEM FOR THE SAME, the relevant portions of which are incorporated herein by reference. 
     The segmented pulley transmission  120  is configured to rotationally couple a first rotating element and a second rotating element in a power train (not shown) and is configured to change the ratio between the first and second rotating elements. In some embodiments, the first rotating element is a driven axle in the power train and the second rotating element is a driving axle in the power train, or vice versa. The segmented pulley transmission  120  comprises a first pulley assembly  122 , a second pulley assembly  124 , an idler pulley  126 , an endless member  128  and an actuator system  130 . As will be appreciated, the endless member  128  is shown as a schematic representation with mating features omitted. The first pulley assembly  122 , the second pulley assembly  124  and the idler pulley  126  are all spaced apart from each other. The endless member  128  extends between and rotationally couples the first pulley assembly  122 , the second pulley assembly  124  and the idler pulley  126 . The actuator system  130  is coupled to the first pulley assembly  122  and may be further coupled to the external housing of the segmented pulley transmission  120 . During installation of the segmented pulley transmission  120 , the first pulley assembly  122  is coupled to the first does not require or preclude the existence of a lower-numbered item (e.g., a “first” item) and/or a higher-numbered item (e,g,, a “third” item). 
     As used herein, the terms “approximately” and “about” represent an amount close to the stated amount that still performs the desired function or achieves the desired result. For example, the terms “approximately” and “about” may refer to an amount&#39; that is within engineering tolerances that would be readily appreciated by a person skilled in the art. 
       FIG. 6  shows a segmented pulley transmission, generally identified by reference character  120 . As will be appreciated, a portion of an external housing of the segmented pulley transmission  120  has been, omitted in  FIG. 6  to view the interior.  FIGS. 1 a  and 1 b    also show the segmented pulley transmission  120  and have been simplified to facilitate understanding of this description and certain elements of the segmented pulley transmission  120  have been omitted, such as the external housing. In sonic embodiments, the segmented pulley transmission  120  may include elements such as those shown and described in PCT International Application No. PCT/CA2018/051475 filed on Nov. 20, 2018, and titled PULLEY ASSEMBLY FOR A SEGMENTED PULLEY TRANSMISSION AND ACTUATOR SYSTEM K)R THE SAME. the relevant portions of which are incorporated heroin by reference. 
     The segmented pulley transmission  120  is configured to rotationally couple a first rotating element and a second rotating element in a power train (not shown) and is configured to change the ratio between the first and second rotating elements. In some embodiments, the first rotating element is a driven axle in the power train and the second rotating element is a driving axle in the power train, or vice versa. The segmented pulley transmission  120  comprises a first pulley assembly  122 , a second pulley assembly  124 , an idler pulley  126 , an endless member  128  and an actuator system  130 . As will be appreciated, the endless member  128  is shown as a schematic representation with mating features omitted, The first pulley assembly  122 , the second pulley assembly  124  and the idler pulley  126  are all spaced apart from each other. The endless member  128  extends between and rotationally couples the first pulley assembly  122 , the second pulley assembly  124  and the idler pulley  126 . The actuator system  130  is coupled to the first pulley assembly  122  and may be further coupled to the external housing of the segmented pulley transmission  120 . During installation of the segmented pulley transmission  120 , the first pulley assembly  122  is coupled to the first rotating element in the power train and the second pulley assembly  124  is coupled to the second rotating element in the power train. 
     The first pulley assembly  122  is configured to be coupled to the first rotating element in the power train. In some embodiments, the first pulley assembly  122 , or a portion thereof, is integrally formed with the first rotating element in the power train. The first pulley assembly  122  is configured to engage the endless member  128  during rotational operation. The first pulley assembly  122  is rotatable about and concentric with a first axis of rotation. The first pulley assembly  122  comprises a first pulley  140  and a second pulley  142 . Both the first pulley  140  and the second pulley  142  are configured for continuous rotational operation with the endless member  128 . During a full rotation of the first pulley assembly  122  about the first axis of rotation, either of the first pulley  140  and the second pulley  142  may continuously engage the endless member  128 . The second pulley  142  is concentric with the first pulley  140  and is movable between an engaged region and a disengaged region, as described below. The second pulley  142  is configured to surround the first pulley  140 , when located in the engaged region. 
     In the context of the subject disclosure, the “engaged region” is a region wherein elements of the first pulley assembly  122  will engage the endless member  128  during rotational operation of the first pulley assembly  122 , when those elements are unsheltered or unobstructed by other elements of first pulley assembly  122 . In contrast, the “disengaged region” is a region wherein elements of the first pulley assembly  122  will not engage the endless member  128  during rotational operation of the first pulley assembly  122 , regardless of their exposure or the position of the other elements of the first pulley assembly  122 . In the subject embodiment, it will be appreciated that the first pulley  140  is permanently located within the engaged region, as the first pulley  140  will always engage the endless member  128  when unobstructed by other elements during rotational operation of the first pulley assembly  122 . In contrast, the second pulley  142  will only be located in the engaged region when moved into a plane defined by the endless member  128 . 
     The first pulley  140  is configured to be coupled to the first rotating element in the power train. In some embodiments, the first pulley  140  is integrally formed with the first rotating element in the power train. The first pulley  140  is configured to engage the endless member  128 , when the first pulley  140  is located in the engaged region. The first pulley  140  is rotatable about and concentric with the first axis of rotation of the first pulley assembly  122 . The first pulley  140  includes an outer peripheral surface  144  for engaging the endless member  128 . The outer peripheral surface  144  is generally circular and may comprise a plurality of outer mating features, for engaging corresponding mating features on the endless member  128 . In some embodiments, the outer mating features are teeth. The first pulley  140  further comprises an inner peripheral surface  146  that is configured to be coupled to the first rotating element of the power train. The inner peripheral surface  146  is generally circular and may comprise a plurality of inner mating features, for coupling to the first rotating element in the power train. In some embodiments, the inner mating features are at least one of keys, teeth or the like. In the subject embodiment, the first pulley  140  comprises a unitary construction. In the subject embodiment, the first pulley  140  is a core pulley of the first pulley assembly  122 . That is, the first pulley  140  is the centermost or smallest diameter pulley in the first pulley assembly  122 . In other embodiments, the first pulley  140  may be another pulley in the first pulley assembly  122 , such as an intermediate pulley that is located between two concentric pulleys in the first pulley assembly  122 . In some embodiments, the first pulley  140  may be a segmented pulley. 
     The second pulley  142  is configured to be coupled to the first rotating element in the power train. The segmented pulley transmission  120  may comprise a plurality of connecting rods  148  for coupling the second pulley  142  to the first rotating element in the power train. In some embodiments, the second pulley  142  is coupled to the first rotating element via the connecting rods  148  and a hub, such as those shown and described in PCT International Application No. PCT/CA 2018 / 051475 . The second pulley  142  is configured to engage the endless member  128 , when the second pulley  142  is located in the engaged region. The second pulley  142  is rotatable about and concentric with the first axis of rotation of the first pulley assembly  122 . The second pulley  142  includes an outer peripheral surface  150  for engaging the endless member  128 . The outer peripheral surface  150  is generally circular and may comprise a plurality of outer mating features, for engaging corresponding mating features on the endless member  128 . In some embodiments, the outer mating features are teeth. The second pulley  142  is a segmented pulley and comprises a plurality of pulley segments  152 . The pulley segments  152  are circularly arranged to form the second pulley  142 . 
     The plurality of pulley segments  152  is configured to engage the endless member  128 . Accordingly, each of the pulley segments  152  includes a body that defines a portion of the outer peripheral surface  150  of the second pulley  142 . The pulley segments  152  are configured to be sequentially movable between the engaged region and the disengaged region to transition the endless member between the first pulley  140  and the second pulley  142 . In the subject embodiment, the pulley segments  152  are configured to be individually movable between the engaged region and the disengaged region. In other embodiments, one or more subsets of the pulley segments  152  are configured to be collectively moved between the engaged region and the disengaged region. For example, in some embodiments, two or more of the pulley segments  152  are configured to be movable together between the engaged region and the disengaged region. 
     The second pulley assembly  124  is configured to be coupled to the second rotating element in the power train. In some embodiments, the second pulley assembly  124 , or a portion thereof, is integrally formed with the second rotating element in the power train. The second pulley assembly  124  is configured to engage the endless member  128 . The second pulley assembly  124  is rotatable about and concentric with a second axis of rotation. In the subject embodiment, the second pulley assembly  124  comprises a single fixed pulley  160 . In other embodiments, the secondary pulley assembly  124  is adjustable and may comprise a plurality of pulleys, such as the first pulley  140  and/or the second pulley  142  described above. The fixed pulley  160  is rotatable about and concentric with the second axis of rotation. The fixed pulley  160  includes an outer peripheral surface  162  for engaging the endless member  128 . The outer peripheral surface  162  is generally circular and may comprise a plurality of outer mating features, for engaging corresponding mating features on the endless member  128 . In some embodiments, the outer mating features are teeth. The fixed pulley  160  further comprises an inner peripheral surface  164  that is configured to be coupled to the second rotating element of the power train. The inner peripheral surface  164  is generally circular and, in some embodiments, comprises a plurality of inner mating features. In some embodiments, the inner mating features are at least one of keys, teeth and the like. 
     The idler pulley  126  is configured to control slack in the endless member  128  between the first pulley assembly  122  and the second pulley assembly  124 . The idler pulley  126  is rotatable about and concentric with a third axis of rotation, and is movable within the segmented pulley transmission  120  to control slack in the endless member  128 . As will be appreciated, controlling slack in the endless member  128  may help to control tension in the endless member  128  and/or may help to align the endless member  128  with the outer mating features of the first pulley assembly  122  and the second pulley assembly  124 . The idler pulley  126  can be moved away from the first pulley assembly  122  and/or the second pulley assembly  124  to reduce slack in the endless member  128 . Alternatively, the idler pulley  126  can be moved towards the first pulley assembly  122  and/or the second pulley assembly  124  to provide slack in the endless member  128 . The idler pulley  126  is configured to engage the endless member  128 . The idler pulley  126  includes an outer peripheral surface  166  for engaging the endless member  128 . The outer peripheral surface  166  is generally circular and may comprise a plurality of outer mating features, for engaging corresponding mating features on the endless member  128 . In some embodiments, the outer mating features are teeth. 
     The endless member  128  is configured to rotationally couple the first pulley assembly  122 , the second pulley assembly  124  and the idler pulley  126 . The endless member  128  extends between the first pulley assembly  122 , the second pulley assembly  124  and the idler pulley  126 . The endless member  128  includes an inner peripheral surface  168  that is configured to engage the outer peripheral surfaces of the first pulley  140 , the second pulley  142 , the fixed pulley  160  and the idler pulley  126 , respectively. Although the endless member  128  is shown in the figures as a schematic representation without any mating features, it will be appreciated that mating features such as teeth and/or holes may be included on at least the inner peripheral surface  168  of the endless member  128 . In some embodiments, the inner peripheral surface  168  includes a plurality of complementary mating features for engaging the outer mating features on the outer peripheral surfaces of the first pulley  140 , the second pulley  142 , the fixed pulley  160  and/or the idler pulley  126 . In other embodiments, the inner peripheral surface  168  may not include any mating features and may be generally smooth, and in such embodiments the inner peripheral surface  168  may engage the first pulley  140 , the second pulley  142 , the fixed pulley  160  and/or the idler pulley  126 . As will be appreciated, the endless member  128  may comprise a chain, a belt or other suitable type of endless member. 
     The actuator system  130  is configured to move the plurality of pulley segments  152  of the second pulley  142  between the engaged region and the disengaged region. The actuator system  130  comprises a deflector  170  and a plurality of followers  172 . Each of the followers  172  is coupled to a respective one of the pulley segments  152 . The deflector  170  is rotatably coupled to the external housing of the segmented pulley transmission  120 . 
     The deflector  170  is configured to rotate between a first position (shown in  FIGS. 1 a  and 1 b   ) a  FIGS. 3 a  and 3 b   ). The deflector  170  is configured to rotate about a generally radial axis of the second pulley  142 . In the first position, the deflector  170  is aligned to engage the plurality of followers  172  during rotational operation of the second pulley  142 , to move the plurality of pulley segments  152  from the disengaged region to the engaged region. In the second position, the deflector  170  is aligned to engage the plurality of followers  172  during rotational operation of the second pulley  142 , to move the plurality of pulley segments  152  from the engaged region to the disengaged region. In some embodiments, the deflector  170  may be further configured to rotate to a neutral position (show in  FIGS. 2 a  and 2 b   ). In the neutral position, the deflector  170  is aligned to avoid engaging the plurality of followers  172  during rotational operation of the second pulley  142 , to avoid moving the plurality of pulley segments  152 . The neutral position can be located between the first position and the second position. In some embodiments, the actuator system  130  may further comprise an electromagnetic actuator, such as one or more solenoids, voice coils and/or electromagnetic motors (not shown), for rotating the deflector  170  between at least the first position and the second position. The deflector  170  comprises an elongate body  174  extending between a root  176  and a distal tip  178 . The deflector  170  is configured to rotate at the root  176 , such that the distal tip  178  moves in a generally axial direction of the second pulley  142 . The deflector  170  defines at least one cam surface. In the subject embodiment, the body  174  deflector defines an engaging cam surface  180  and a disengaging cam surface  182 . 
     The engaging cam surface  180  and the disengaging cam surface  182  are located on opposite sides of the elongate body  174 . The engaging cam surface  180  is configured to engage the plurality of followers  172  to move the plurality of pulley segments  152  from the disengaged region to the engaged region. In contrast, the disengaging cam surface  182  is configured to engage the plurality of followers  172  to move the plurality of pulley segments  152  from the engaged region to the disengaged region. As will be described below, the engaging cam surface  180  directs each of the followers  172  from an engaged position (shown in  FIGS. 3 a  and 3 b    for follower  172   a ) to a disengaged position (shown in  FIGS. 5 a  and 5 b    for follower  172   a ) during rotational operation of the second pulley  142 . In contrast, the disengage cam surface  182  directs each of the followers  172  from the engaged position to the disengaged position during rotational operation of the second pulley  142 . 
     The deflector  170  is configured to rotate between a first position (shown in  FIGS. 1 a  and 1 b   ) and second position (shown in  FIGS. 3 a  and 3 b   ). The deflector  170  is configured to rotate about a generally radial axis of the second pulley  142 . In the first position, the deflector  170  is aligned to engage the plurality of followers  172  during rotational operation of the second pulley  142 , to move the plurality of pulley segments  152  from the disengaged region to the engaged region. In the second position, the deflector  170  is aligned to engage the plurality of followers  172  during rotational operation of the second pulley  142 , to move the plurality of pulley segments  152  from the engaged region to the disengaged region. In some embodiments, the deflector  170  may be further configured to rotate to a neutral position (show in  FIGS. 2 a  and 2 b   ), In the neutral position, the deflector  170  is aligned to avoid engaging the plurality of followers  172  during rotational operation of the second pulley  142 , to avoid moving the plurality of pulley segments  152 . The neutral position can be located between the first position and the second position. In some embodiments, the actuator system  130  may further comprise an electromagnetic actuator, such as one or more solenoids, voice coils end/or electromagnetic motors (not shown), for rotating the deflector  170  between at least the first position and the second position. The deflector  170  comprises an elongate body  174  extending between a root  176  and a distal tip  178 . The deflector  170  is configured to rotate at the root  176 , such that the distal tip  178  moves in a generally axial direction of the second pulley  142 . The deflector  170 ′defines at least one cam surface. In the subject embodiment, the body  174  deflector defines an engaging cam surface  180  and a disengaging cam surface  182 . 
     The engaging earn surface  180  and the disengaging cam surface  182  are located on opposite sides of the elongate body  174 . The engaging cam surface  180  is configured to engage the plurality of followers  172  to move the plurality of pulley segments  152  from the disengaged region to the engaged region. In contrast, the disengaging cam surface  182  is configured to engage the plurality of followers  172  to move the plurality of pulley segments  152  from the engaged region to the disengaged region. As will be described below, the engaging cam surface  180  directs each of the followers  172  from an engaged position (shown in  FIGS. 3 a  and 3 b    for follower  172   a ) to a disengaged position (shown in  FIGS. 5 a    and Sb for follower  172   a ) during rotational operation of the second pulley  142 . In contrast, the disengage cam surface  182  directs each of the followers  172  from the engaged position to the disengaged position during rotational operation of the second pulley  142 . 
     The plurality of followers  172  is configured to move the plurality of pulley segments  152  between the engaged region and the disengaged region. Accordingly, each of the followers  172  is coupled to a respective one of the pulley segments  152 . In the subject embodiment, each of the followers  172  comprises a body  184  and a protrusion  186  extending from the body  184 . The body  184  is configured to couple the follower  172  to the respective one of the pulley segments  152 . In some embodiments, body  184  is coupled to the pulley segment  152  by fasteners. In other embodiments, the body  184  is coupled to the pulley segment  152  by interlocking features, welding or other suitable mechanism. The protrusion  186  extends from the body  184  in a generally radial direction of the second pulley  142 . The protrusion  186  is axially offset from the outer peripheral surface  150  of the second pulley  142 . That is, the protrusion  186  is offset from the outer peripheral surface  150  in a direction aligned with the axis of rotation of the second pulley  142 . The protrusion  186  is configured to engage the deflector  170  during rotational operation of the second pulley  142 , to move the coupled pulley segment  152  between the engaged region and the disengaged region. In the subject embodiment, the protrusion  186  is a roller that is configured to contact the cam surfaces  180 ,  182  of the deflector  170  and roll therealong, to push the coupled pulley segment  152  between the engaged region and the disengaged region. 
     During rotational operation of the segmented pulley transmission  120 , the endless member  128  will contact and engage the first pulley assembly  122  within an angular region defined as the contact zone. Conversely, the endless member  128  will not contact or engage the first pulley assembly  122  within an angular region defined as the non-contact zone. In  FIGS. 1 b  to 5 b   , the non-contact zone is located adjacent the deflector  170  and extends generally from the second pulley assembly  124  to the idler pulley  126 . The pulley segments  152  of the second pulley  142  can be moved into or out of the engaged region while positioned in the non-contact zone without interfering with the endless member  128  and while the segmented pulley transmission  120  is under load. As will be appreciated, the non-contact zone will vary depending on whether or not the first pulley  140  is engaged with the endless member  128  and which, if any, of the pulley segments  152  of the second pulley  142  are engaged with the endless member  128 . 
     By sequentially moving the pulley segments  152  into or out of the engaged region while positioned in the non-contact zone, the endless member  128  may transition from engaging one of the first pulley  140  and the second pulley  142 , defined as an “origin pulley,” to engaging the other of the first pulley  140  and the second pulley  142 , defined as a “destination pulley,” without interrupting rotational operation of the segmented pulley transmission  120  and without interrupting a load transmitted through the segmented pulley transmission  120 . Transition the endless member  128  between the origin pulley and the destination pulley is referred to as a “shift event.” 
       FIGS. 1 a , 1 b  to 5 a , 5 b    show a sequence for transitioning one of the pulley segments  152   a  from the engaged region to the disengaged region, during a disengaging shift event. The disengaging shift event transitions the endless member  128  from the second pulley  142  to the first pulley  140 , thereby disengaging the endless member  128  from the second pulley  142 . As will be appreciated, the pulley segment  152   a  that is moving from the engaged region to the disengaged region in  FIGS. 1 a , 1 b  to 5 a , 5 b    may be described as a transitioning pulley segment, and is one of the plurality of pulley segments  152  of the second pulley  142 . Similarly, the follower  172   a  coupled to the transitioning pulley segment  152   a  may be described as a transitioning follower and is one of the plurality of followers  172 . Prior to the disengaging shift event, the endless member  128  is engaged with the second pulley  142  and all of the pulley segments  152  are in the engaged region. In the subject embodiment, prior to the disengaging shift event, the deflector  170  is located in the first position (as shown in  FIGS. 1 a  and 1 b   ). In other embodiments, the deflector  170  is located in the neutral position prior to a shift event. 
     To begin the disengaging shift event, the deflector  170  moves to the second position as the first pulley assembly  122  rotates. In the subject embodiment, the deflector  170  starts in the first position (shown in  FIGS. 1 a  and 1 b   ) and passes through the neutral position (shown in  FIGS. 2 a  and 2 b   ), as the deflector  170  moves to the second position (shown in  FIGS. 3 a  and 3 b   ). The deflector  170  moves from the first position to the second position by rotating at the root  176 . Rotation of the deflector  170  is timed such that the distal tip  178  of the deflector  170  passes between consecutive followers in the plurality of followers  172 . In the subject embodiment, the distal tip  178  of the deflector  170  passes between the transitioning follower  172   a  and an immediately preceding one of the followers  172 . 
     At the steps shown in  FIGS. 3 a  and 3 b  to 5 a  and 5 b   , the deflector  170  is maintained in the first position. As the first pulley assembly  122  continues to rotate, the transitioning pulley segment  152   a  enters the non-contact zone and the transitioning follower  172   a  engages the deflector  170  to move the transitioning pulley segment  152   a  from the engaged region to the disengaged region. As will be appreciated, in the subject embodiment, the transitioning pulley segment  152   a  is moved out of the engaged region by retracting the transitioning pulley segment  152   a  out of the pla 
     llower  172   a  is directed from the engaged position to the disengaged position as the first pulley assembly  122  rotates. As will be appreciated, when any one of the followers  172  is in the engaged position, the pulley segment  152  coupled to that follower  172  will be in the engaged region. In contrast, when any one of the followers  172  is in the disengaged position, the pulley segment  152  coupled to that follower will be in the disengage region. Accordingly, in the subject embodiment, as the transitioning follower  172   a  is directed from the engaged position to the disengaged position, the transitioning pulley segment  152   a  moves from the engaged region to the disengaged region. Once the transitioning pulley segment  152   a  is in the disengaged region and the transitioning follower  172   a  is in the disengaged position, the transitioning follower  172   a  disengages the deflector  170  and will no longer contact the deflector  170  as the first pulley assembly  122  continues to rotate. In the subject embodiment, the transitioning follower  172   a  disengaged the deflector  170  at or before passing the axis of rotation of the deflector  170  (as shown in  FIG. 5 a   ) during the disengaging shift event. As will be appreciated, by disengaging the deflector  170  at or before passing the axis of rotation thereof, the transitioning follower  172   a  can avoid applying a torque to the deflector  170  that would otherwise urge the deflector  170  out of the second position and back towards the first position, which could interfere with the disengaging shift event. 
     As will be appreciated, the steps shown in  FIGS. 3 a , 3 b  to 5 a , 5 b    are repeated with the remaining followers  172  as the first pulley assembly  122  continues to rotate, to move the remaining pulley segments  152  from the engaged region to the disengaged region. Once all of the pulley segments  152  have been moved to the disengaged region, the disengaging shift event is complete and the endless member  128  will be engaged with the first pulley  140  for continuous rotational operation. In some embodiments, the deflector  170  is moved to the neutral position once the disengaging shift event is complete, to prepare for a subsequent shift event. In other embodiments, the deflector  170  remains in the second position once the disengaging shift event is complete. 
     To transition the endless member  128  from the first pulley  140  to the second pulley  142 , a engaging shift event is carried out. At the outset of the engaging shift event, the deflector  170  moves to the first position (shown in  FIGS. 1 a  and 1 b   ) by rotating at the root  176 . Again, rotation of the deflector  170  is timed such that the distal tip  178  of the deflector passes between consecutive follower in the plurality of followers. 
     As the first pulley assembly  122  continues to rotate, each of the pulley segments  152  sequentially enters the non-contact zone and is moved from the disengaged region to the engaged region. As will be appreciated, in the subject embodiment, each of the pulley segments  152  are moved into the engaged region by extending the pulley segments  152  into the plane defined by the endless member  128 . When a pulley segment  152  is moving from the disengage region to the engaged region, that pulley segment  152  is defined as a transitioning pulley segment  152   a  and the follower  172  coupled to the transitioning pulley segment  152   a  is defined as a transitioning follower  172   a . As the first pulley assembly  122  rotates, the transitioning follower  172   a  contacts the engaged cam surface  180  of the deflector  170  and the transitioning follower  172   a  is directed from the disengaged position to the engaged position. As the transitioning followers  172   a  is directed from the disengaged position to the engaged position, the transitioning pulley segment  152   a  moves from the disengaged region to the engaged region. Once the transitioning pulley segment  152  is in the engaged region and the transitioning follower  172   a  is in the engaged position, the transitioning follower  172   a  disengaged the deflector  170  and will no longer contact the deflector  170  as the first pulley assembly  122  continues to rotate. In some embodiments, the transitioning follower  172   a  disengaged the deflector  170  at or before passing the axis of rotation of the deflector  170  during the engaging shift event. As will be appreciated, by disengaging the deflector  170  at or before passing the axis of rotation thereof, the transitioning follower  172   a  can avoid applying a torque to the deflector  170  that would otherwise urge the deflector  170  out of the first position and back towards the second position, which could interfere with the engaging shift event. 
     As will be appreciated, the steps described above are repeated for each of the remaining followers  172  as the first pulley assembly  122  continues to rotate, to move each of the remaining pulley segments  152  from the disengaged region to the engaged region. Once all of the pulley segments  152  have been moved to the engaged region, the engaging shift event is complete and the endless member  128  will be engaged with the second pulley  142  for continuous rotational operation. In some embodiments, the deflector  170  is moved to the neutral position once the engaging shift event is complete, to prepare for a subsequent shift event. In other embodiments, the deflector  170  remains in the first position once the engaging shift event is complete. 
     Although the first pulley system  122  has been shown and described herein as comprising two concentric pulleys, namely the first pulley  140  and the second pulley  142 , it will be appreciated that in other embodiments the first pulley system may comprise a greater number of concentric pulleys when further ratios for the segmented pulley transmission  120  are desired. 
     Although each of the followers  172  have been shown and described as comprising a body  184  coupled to a respective one of the pulley segments  152  and a protrusion  186  extending from the body  184 , it will be appreciated that in other embodiments each of the followers may be integrally formed with a respective one of the pulley segments. As will be appreciated, in embodiments where the followers are integrally formed with the pulley segments, the body of each of the followers may be omitted and the protrusion may extend directly from the respective one of the pulley segments. 
     Although the protrusions  186  has been shown and described herein as a roller that is configured to contact the cam surfaces  180 ,  182  and roll therealong, it will be appreciated that in other embodiments the protrusion may be a slider that is configured to contact the cam surfaces and slide therealong. In some embodiments, the slider is made of plastic. In some embodiments the slide is made of nylon. 
     Although embodiments have been described above and are shown in the accompanying drawings, it will be appreciated by those skilled in the art that variations and modifications may be made without departing from the scope as defined by the appended claims, and the scope of the claims should be given the broadest interpretation consistent with the specification as a whole.