Abstract:
A hold and release mechanism for holding and releasing a cable includes a toothed-disk arrangement coupled with the cable take-up device for rotating together about a first axis. The toothed-disk arrangement includes a plurality of teeth at an outer periphery of the toothed-disk arrangement. The plurality of teeth includes locking and safety teeth. The locking teeth are disposed in a first tooth plane orthogonal to the first axis. The safety teeth are disposed in a second tooth plane that is orthogonal to the first axis and offset relative to the first tooth plane. An adjustable locking pawl pivotably mounted about a second axis includes locking and safety catches. The locking catch engages with one of the locking teeth for holding the toothed-disk arrangement in a first rotational position. The safety catch engages with one of the safety teeth for holding the toothed-disk arrangement in a second rotational position.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a holding and releasing mechanism for holding and releasing a cable take-up device of a step shifter, for example, and a step shifter comprising the holding and releasing mechanism, as well as a system which in turn comprises the step shifter. 
     Step shifters in which a holding and releasing mechanism—according to the invention can be used are particularly useful in bicycles. They can assist the user of the bicycle to wind and release the shifting cable step-by-step wherein the actuating levers generally return back to the initial position after they are actuated. The term “trigger switch” or “trigger shifter” may be used interchangeably for step shifter. 
     Step shifters, or trigger switches, are known from patent specifications EP 0 361 335 B1, EP 1 232 940 B2, EP 1 366 981 B1 and FR 2 701 917 A1, among others. 
     Known step shifters each comprise a cable pull-up or winding mechanism for the shifting cable as well as a mechanism for holding and releasing the shifting cable. The present invention relates to an especially advantageous embodiment of a holding and releasing mechanism as well as a step shifter in which this holding and releasing mechanism is used, as well as a shifting system in which this step shifter is in turn used. 
     The holding and releasing mechanism of EP 0 361 335 B1 comprises first and second locking elements that pivot in opposite directions for alternatingly engaging into a toothed locking disk. In a release, the locking element presently engaged with the locking disk is disengaged out from the locking disk. The locking disk can now rotate until the other respective locking element engages with the locking teeth. When the release handle is returned back to its initial position, the second locking element moves out of engagement with the locking disk and the locking disk moves until it re-engages the first locking element. 
     A holding and releasing mechanism is known from EP 1 232 940 B2. Here, a pivotable locking latch has a locking catch which initially engages with a first tooth of a locking disk, which fixes the locking disk. When the locking catch is now pivoted out of the engagement area of the first tooth, the locking disk can be rotated to the point that a tooth of the locking disk adjacent to the first tooth comes into engagement with a safety catch of the latch which is pivoted at the same time into the engagement area of the teeth. If the locking latch is now pivoted back to its initial position, the locking toothed disk can rotate further until the locking catch of the locking latch comes into engagement with a third tooth which is also adjacent to the first tooth, the locking toothed disk being held there again. 
     Another holding and releasing mechanism is known from EP 1 366 981 B1 in which a slidingly held locking latch engages alternatingly with locking and safety teeth disposed on opposite sides of a locking toothed disk when a release lever is actuated. 
     Finally, also known from FR 2 701 917 A1 is a holding and releasing mechanism in which a locking latch initially engages with a locking tooth by way of a locking catch. When a release lever is actuated, the locking latch pivots such that the locking catch comes out of engagement with the locking tooth, whereupon a safety catch of the latch comes into engagement with a safety tooth while the locking toothed disk has rotated by a specific angular amount. When the locking latch is pivoted back, the locking catch thereof re-engages with a locking tooth. 
     BRIEF SUMMARY OF THE INVENTION 
     In consideration of the known holding and releasing mechanisms for step shifters, it is now an object of the present invention to provide such a holding and releasing mechanism that enables a particularly compact and space-saving design. In particular, it is an object of the present invention to provide a hold and release mechanism that allows a particularly large number of actuation positions due to the design thereof. A further object of the present invention is to provide a reliably functioning hold and release mechanism. Another object of the present invention is to provide a hold and release mechanism that facilitates ease of adjustability for the overall system incorporating the mechanism. 
     To achieve at least one of the objects, according to a first aspect, a hold and release mechanism is provided for holding and releasing a cable take-up device of a step shifter, for example. The mechanism holds an actuating cable by way of the cable take-up device in a plurality of actuation positions comprising an actuation position of maximum pull-out (wherein cable is released or unwound therefrom) of the actuation cable out of or off of the cable take-up device and an actuation position of maximum pull-in (wherein cable has been take-in or wound on) of the actuation cable into the cable take-up device. The mechanism provides stepped release of the actuation cable in a pull-out direction and includes a toothed-disk arrangement that is part of the cable take-up device as a single piece or is connected or can be connected rigidly thereto and can rotate therewith about a first axis. The toothed-disk arrangement comprises a plurality of teeth at the outer periphery thereof. An adjustable locking latch or locking pawl is preferably pivotable about a second axis. The latch, in a first position when the toothed-disk arrangement is located in any of various first rotational positions, in particular in a first rotational position engaging by way of a locking catch with a tooth from the plurality of teeth that acts as a locking tooth associated with the respective first rotational position, holds or stops the toothed-disk arrangement and thereby the cable take-up device in the respective first rotational position. The latch also, in a second position when the toothed-disk arrangement is located in various second rotational positions, in particular in a second rotational position engaging by way of a safety catch with a tooth from the plurality of teeth that acts as a safety tooth associated with the respective second rotational position, holds or stops the toothed-disk arrangement and thereby the cable take-up device in the respective second rotational position. The first rotational positions correspond to the actuation positions of the actuation cable or a subset of the actuation positions and the second rotational positions correspond to intermediate positions of the actuation cable when the actuation cable is transitioned between adjacent actuation positions through release of the actuation cable. 
     According to the invention, the plurality of teeth of the toothed-disk arrangement comprises a first group of teeth and a second group of teeth. The teeth of the first group of teeth act as locking teeth and are disposed in a first tooth plane orthogonal to the first axis. The teeth of the second group of teeth act as safety teeth and are disposed in a second tooth plane that is orthogonal to the first axis and offset relative to the first tooth plane. This results in a particularly large angular range of the toothed disks arrangement for arranging the respective groups of teeth, which permits a space-saving design of the hold and release mechanism, and in particular a large number of actuation positions. 
     In a hold and release mechanism according to the invention, the first group of teeth can have the same number of teeth as the second group of teeth, wherein this number can preferably correspond to the number of actuation positions of the actuation cable. 
     Furthermore, with regard to the geometric design of the hold and release mechanism it can be advantageous to design the locking latch in such a way that the locking catch is located in the first tooth plane and the safety catch is located in the second tooth plane. 
     It is an advantage that the teeth of the first group of teeth extend over a first angular range relative to the first rotational axis and the teeth of the second group of teeth extent over a second angular range relative to the first rotational axis, the second range overlapping the first angular range. 
     The toothed disk arrangement can be manufactured by having it be comprised of two toothed disks that are connected together rigidly, one of which contains the first group of teeth and the second of which contains the second group of teeth. This allows for a simplified and cost-effective manufacture of the toothed disk arrangement. Alternatively, it is of course also possible to manufacture the toothed disk arrangement and both tooth planes in one piece. 
     To achieve at least one of the objects, according to a second aspect a hold and release mechanism is provided for holding and releasing a cable take-up device of a step shifter for example, for holding an actuating cable held by way of the cable take-up device in a plurality of actuation positions comprising an actuation position of maximum pull-out of the actuation cable out of the cable take-up device and an actuation position of maximum pull-in of the actuation cable into the cable take-up device and for stepped releasing of the actuation cable in a pull-out direction. The mechanism comprises a toothed-disk arrangement that is part of the cable take-up device as a single piece or is connected or can be connected rigidly thereto and can rotate therewith about a first axis. The toothed-disk arrangement comprises a plurality of teeth at the outer periphery thereof. An adjustable locking latch is preferably pivotable about a second axis. The latch, in a first position when the toothed-disk arrangement is located in various first rotational positions, in particular in a first rotational position engaging by way of a locking catch with a tooth from the plurality of teeth that acts as a locking tooth associated with the respective first rotational position, holds or stops the toothed-disk arrangement and thereby the cable take-up device in the respective first rotational position. The latch also, in a second position when the toothed-disk arrangement is located in various second rotational positions, in particular in a second rotational position engaging by way of a safety catch with a tooth from the plurality of teeth that acts as a safety tooth associated with the respective second rotational position, holds or stops the toothed-disk arrangement and thereby the cable take-up device in the respective second rotational position. The first rotational positions correspond to the actuation positions of the actuation cable or a subset of the actuation positions and the second rotational positions correspond to intermediate positions of the actuation cable when the actuation cable is transitioned between adjacent actuation positions through release of the actuation cable. 
     According to the invention, the actuation position of maximum pull-out of the actuation cable is not associated with any of the plurality of teeth acting as a stopping tooth, so that the stopping and holding of the toothed-disk arrangement in a rotational position of the toothed-disk arrangement corresponding to the actuation position of maximum pull-out of the actuation cable, and thus the cable take-up device, is not achieved through engagement of the locking catch with a tooth. This makes it possible for the actuation position of maximum pull-out of the actuation cable to be finely adjusted within a certain range independent of the holding and releasing mechanism. In the process, the first and second groups of teeth can be arranged as depicted above into two planes separated from one another, but they can also lie in the same plane according to the invention. Both possible arrangements of teeth permit a flexible design of toothed-disk arrangement and thereby an advantageously compact hold and release mechanism. 
     To achieve at least one of the objects, according to a third aspect a hold and release mechanism is provided for holding and releasing a cable take-up device of a step shifter for example, for holding an actuating cable held by way of the cable take-up device in a plurality of actuation positions comprising an actuation position of maximum pull-out of the actuation cable out of the cable take-up device and an actuation position of maximum pull-in of the actuation cable into the cable take-up device and for stepped releasing of the actuation cable in a pull-out direction. The mechanism comprises a toothed-disk arrangement that is part of the cable take-up device as a single piece or is connected or can be connected rigidly thereto and can rotate therewith about a first axis. The toothed-disk arrangement comprises a plurality of teeth at the outer periphery thereof. An adjustable locking latch is preferably pivotable about a second axis. The latch, in a first position when the toothed-disk arrangement is located in various first rotational positions, in particular in a first rotational position engaging by way of a locking catch with a tooth from the plurality of teeth that acts as a locking tooth associated with the respective first rotational position, holds or stops the toothed-disk arrangement and thereby the cable take-up device in the respective first rotational position. The latch also, in a second position when the toothed-disk arrangement is located in various second rotational positions, in particular in a second rotational position engaging by way of a safety catch with a tooth from the plurality of teeth that acts as a safety tooth associated with the respective second rotational position, holds or stops the toothed-disk arrangement and thereby the cable take-up device in the respective second rotational position, wherein the first rotational positions correspond to the actuation positions of the actuation cable or a subset of the actuation positions and the second rotational positions correspond to intermediate positions of the actuation cable when the actuation cable is transitioned between adjacent actuation positions through release of the actuation cable. 
     According to the invention, the toothed-disk arrangement and thereby the cable take-up device can be transitioned from a rotational position corresponding to an actuating cable actuation position that precedes the actuation position of maximum pull-out of the actuation cable, directly to a rotational position of the toothed-disk arrangement that corresponds to the actuation position of maximum pull-out of the actuation cable and thereby of the cable take-up device by releasing the actuation cable without holding the toothed-disk arrangement and thereby the cable take-up device at an intermediate position by way of the safety catch and a tooth of the plurality of teeth that acts as a safety tooth. Since in such a hold and release mechanism the number of locking and/or safety teeth can be reduced, it can be designed to be particularly compact. 
     To achieve at least one of the objects, according to a fourth aspect a hold and release mechanism is provided for holding and releasing a cable take-up device of a step shifter for example, for holding an actuating cable held by way of the cable take-up device in a plurality of actuation positions comprising an actuation position of maximum pull-out of the actuation cable out of the cable take-up device and an actuation position of maximum pull-in of the actuation cable into the cable take-up device and for stepped releasing of the actuation cable in a pull-out direction. The mechanism comprises a toothed-disk arrangement that is part of the cable take-up device as a single piece or is connected or can be connected rigidly thereto and can rotate therewith about a first axis. The toothed-disk arrangement comprises a plurality of teeth at the outer periphery thereof; an adjustable locking latch preferably pivotable about a second axis. The latch, in a first position when the toothed-disk arrangement is located in various first rotational positions, in particular in a first rotational position engaging by way of a locking catch with a tooth from the plurality of teeth that acts as a locking tooth associated with the respective first rotational position, holds or stops the toothed-disk arrangement and thereby the cable take-up device in the respective first rotational position. The latch also, in a second position when the toothed-disk arrangement is located in various second rotational positions, in particular in a second rotational position engaging by way of a safety catch with a tooth from the plurality of teeth that acts as a safety tooth associated with the respective second rotational position, holds or stops the toothed-disk arrangement and thereby the cable take-up device in the respective second rotational position. The first rotational positions correspond to the actuation positions of the actuation cable or a subset of the actuation positions and the second rotational positions correspond to intermediate positions of the actuation cable when the actuation cable is transitioned between adjacent actuation positions through release of the actuation cable. 
     According to the invention, relative to the first rotational axis an angular distance between the locking catch and the safety catch of the locking latch is larger than twice the angular distance, or double the minimum angular distance, between the directly adjacent teeth that act as locking teeth, and is smaller than the angular distance of the rotational positions of the toothed-disk arrangement corresponding to the actuation positions of maximum pull-out and maximum pull-in of the actuation cable, respectively. 
     In an advantageous embodiment, the majority of the teeth of the toothed-disk arrangement include a group of teeth that act both as locking teeth and safety teeth depending on the rotational position of the toothed-disk arrangement, wherein the toothed-disk arrangement preferably comprises a toothed disk that includes the group of teeth. This can reduce the total number of teeth in the toothed-disk arrangement, which has a particularly advantageous effect on the number of possible actuation positions of the toothed-disk arrangement. 
     In the process, relative to the first rotational axis, i.e. the rotational axis of the toothed-disk arrangement, the angular distance between the locking catch and the safety catch of the locking latch can furthermore be greater than an angular distance or a minimum angular distance between directly adjacent teeth of the group of teeth that act both as locking teeth and as safety teeth depending on the rotational position of the toothed-disk arrangement. It can also be provided that relative to the rotational axis of the toothed-disk arrangement the angular distance between the locking catch and the safety catch of the locking latch is greater than an angular distance or a minimum angular distance between two teeth of the first number of teeth acting as locking teeth and smaller than the largest distance between two teeth of this first number of teeth. Both improvement suggestions allow for an advantageous and space-saving design of the hold and release mechanism. 
     For further improvement of the holding characteristics of the hold and release mechanism according to the invention, the locking latch can be biased in the direction of the first position thereof by way of a first spring arrangement. 
     In order to further facilitate the pull-out of the actuation cable, the toothed-disk arrangement or cable take-up device can also be biased by way of a second spring arrangement in the direction of pull-out of the actuation cable. 
     In a hold and release mechanism according to the invention, the first axis and the second axis can be either essentially parallel or can be tilted relative to one another by a pre-determined angle. 
     Also, in a hold and release mechanism according to the invention, a lock-out device can be provided which is designed for removing or keeping removed the locking latch out of the first rotational position thereof in at least one pre-determined rotational angle range of the toothed-disk arrangement encompassing at least one rotational position of the toothed-disk arrangement corresponding to an actuation position of the actuation cable. The lock-out device can comprise at least a cam element that is part of the cable take-up device or the toothed-disk arrangement in one piece or is connected to one of them rigidly and is designed to act directly on the locking latch or act thereon through at least one other element of the lock-out device so that the locking latch is removed from the first pivot position thereof or kept removed therefrom. 
     One of the objects cited above is also achieved by way of a hold and release mechanism of this class, the mechanism comprising a lock-out device as mentioned in the paragraph directly above. The applicant claims independent protection for this. 
     In particular, the at least one pre-determined rotational angle range of the toothed-disk arrangement can include the rotational position of the toothed-disk arrangement corresponding to the actuation position of maximum pull-out of the actuation cable. 
     In a hold and release mechanism according to the invention, the locking latch can be shifted in the pull-out direction from the first position toward the second position by at least one step using an actuation device for purposes of releasing the actuation cable. It is primarily conceived that the locking latch can pivot from the first pivot position toward the second pivot position. 
     It is an advantage that the hold and release mechanism according to the invention can be designed such that the toothed-disk arrangement can assume six, preferably at least eight, at most preferably at least ten different rotational positions, each of which can be assigned to an actuation position of the actuation cable. 
     Although the object according to the invention is achieved by way of a hold and release mechanism according to one of the four aspects of the invention, alternatively incorporating one or more of the improvement suggestions, it is of course feasible that the first, second, third and fourth aspects of the invention can also be implemented in combination. 
     Furthermore, the present invention provides a step shifter, in particular for a bicycle, for actuating at least one device, for example a switching arrangement that can be actuated for selecting gears of a bicycle gear shifting mechanism, using an actuation cable. The step shifter according to the invention comprises a rotatable cable take-up device that holds the actuation cable. The take-up device is rotatable between rotational positions corresponding to a plurality of actuation positions of the actuation cable and that include an actuation position of maximum pull-out of the actuation cable and an actuation position of maximum pull-in of the actuation cable. The cable take-up device can be held or stopped from rotating in a release direction by way of a hold and release mechanism according to the invention according to at least one of the listed aspects one through four in a plurality of first rotational positions of the cable take-up device and can be released in a pull-out direction for rotation in the release direction by way of the hold and release mechanism according to the invention for step-by-step releasing of the actuation cable. 
     Furthermore, the step shifter according to the invention can comprise a manually actuatable pull-in mechanism that acts directly or indirectly on the cable take-up device. The pull-in mechanism is able to rotate the cable take-up device step-by-step in a pull-in direction opposite to the release direction between the rotational directions corresponding to the actuation positions of the actuation cable. 
     The present invention also provides a system comprising a step shifter according to the invention and a device that can be actuated by way of the step shifter according to the invention and the actuation cable. To this end, it is suggested that the device should include a return spring arrangement that biases the actuation cable in the direction of the actuation position of maximum pull-out. 
     It is advantageous that the actuation cable can be connected to a moveably arranged element of the device, the element being biased by the return spring arrangement in the direction to a preferably adjustable stop position corresponding to the actuation position of maximum pull-out of the actuation cable and in which no biasing forces from the return spring arrangement are exerted on the actuation cable. In this regard, the invention suggestions can be implemented according to the second and third aspect in particularly advantageous manner. 
     In the case of a derailleur of a bicycle chain switching system as the device to be actuated by way of the step shifter, adjustment of a derailleur base position can be made this way. 
     These and other features and advantages of the present invention will be more fully understood from the following description of one or more embodiments of the invention, taken together with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective top view of a step shifter according to the invention that comprises a first embodiment of a hold and release mechanism according to the invention; 
         FIG. 2-8  are top views of a step shifter according to the invention that comprises a second embodiment of a hold and release mechanism according to the invention, wherein  FIGS. 2 through 6  illustrate a transition of the hold and release mechanism from a fourth to a fifth actuation position,  FIG. 7  shows the hold and release mechanism in a ninth actuation position and  FIG. 8  illustrates an actuation position of maximum pull-out; 
         FIG. 9  is a general schematic side view of a toothed-disk arrangement and a cable take-up device of a step shifter of the second embodiment; and 
         FIG. 10  a general schematic representation of a system comprising a step shifter according to the invention, an actuation cable and a device actuated by the step shifter. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the invention are described below with reference to the drawings. 
     Shown in  FIG. 1  in an oblique top view is a step shifter  20  according to the invention. The step shifter  20  comprises a base plate  22  to which is attached a toothed-disk arrangement  24  that can rotate about an axis X. Here, the device used for attachment is left out of the figure for reasons of clarity. The toothed-disk arrangement comprises an upper toothed disk  24   a  and a lower toothed disk  24   b  which on one hand are connected rigidly to one another and on the other hand are connected rigidly to a cable take-up device, which is not shown. 
     The step shifter further comprises a locking latch  28  that can pivot about a second axis Y, one end of the latch having a locking catch  30  that faces the toothed-disk arrangement  24  and the other end thereof having a safety catch  32  likewise facing the toothed-disk arrangement  24 . The locking latch  28  may also be referred to as a locking pawl. Here, the axis of rotation X of the toothed-disk arrangement and the pivot axis Y of the locking latch  28  are aligned parallel to one another. Two bending edges or angled sections  28   a  and  28   b  in the locking latch  28  place the locking catch  30  in the plane of the lower toothed disk  24   b  and the safety catch  32  in the plane of the upper toothed disk  24   a . The locking latch  28  further comprises an obliquely upward pointing engaging element  34  on the side where the safety catch  32  is located, the element being graspable by a first actuation lever, not shown here, in such a way that the locking latch  28  is pivoted about the pivot axis Y thereof. 
     The step shifter according to the invention can be used to actuate a bicycle gear shifter, for example, in particular a rear derailleur in particular in this case. 
     The lower toothed disk  24   b  comprises teeth on the outer periphery thereof at angular positions labeled as 1-10, the teeth also being identified as 1-10 below, and of the positions only the teeth corresponding to angular positions 7-10 are shown in  FIG. 1 . Also identified below are the actuation positions of the toothed-disk arrangement  28  in which the locking catch  30  and one of teeth 1-10 are engaged, identified as the first through the tenth actuation position. Here, the first actuation position corresponds to the actuation position of maximum pull-in of an actuation cable held by the cable take-up device, whereas in the other actuation positions the actuation cable is pulled successively further out. 
     The upper toothed disk  24   a  also comprises a plurality of teeth  26 , the number of which is the same as the number of teeth in the lower toothed disk, only four of which are shown in analogous fashion as in the representation of the lower toothed disk. 
     Also, the step shifter  20  shown comprises a pull-in mechanism  36  which can be actuated by way of a second actuation lever  38 . No explanation of the way in which the pull-in mechanism  36  functions is given at this point. For a detailed explanation of such a mechanism, reference is made rather to EP 1 366 981 A2. 
     The functioning of the hold and release mechanism  29  of the step shifter  20 , the mechanism formed through the cooperation of the toothed-disk arrangement  24  and the locking latch  28 , is explained below. In the rotational position of the toothed-disk arrangement  24  and the pivot position of the locking latch  28  as shown in  FIG. 1 , the locking catch  30  of the locking latch  28  and the tooth 10 of the lower toothed disk  24   b  cooperated in such a way that a clockwise rotation of the toothed-disk arrangement  24  is prevented. Here, the toothed-disk arrangement  24  is biased in the clockwise direction by way of a spring element, which is not shown, whereas the locking latch  28  is biased in the pivot position (the hold position) shown in  FIG. 1  by way of another spring element which is also not shown. Here, teeth 1-10 and the locking catch  30  are sloped in such a way that counterclockwise rotation of the toothed-disk arrangement  24  by the pull-in mechanism is possible when the locking latch  28  is in the hold position. In the process, the locking latch  28  pivots out from the hold position for a brief period through the interaction of the sloped teeth 1-10 and the locking catch  30  so that the respective tooth 1-10 can slide past and underneath the locking catch  30 . This process corresponds to a switching from a higher gear to a lower gear. 
     On the other hand, if the user switches from a low gear to a higher one, he must exert a force onto the engaging lug  34  of the locking latch  28  by way of the actuation lever not first shown. This pivots the locking latch  28  from the hold position thereof to a safety position in which the safety catch  32  is pivoted toward the toothed disk  24   a , but the locking catch  30  is pivoted away out of engagement with the cogging of the toothed disk  24   b . Since as discussed the toothed-disk arrangement  24  is biased in the clockwise direction about axis of rotation X, it begins to rotate in this direction. Since the safety catch  32  is now located in the safety position of the locking latch  28  near teeth  26  of the upper toothed disk  24   a , the toothed-disk arrangement  24  can be rotated clockwise but only as far as it takes for the safety catch  32  to engage with the next adjacent or subsequent of the teeth  26  of the upper toothed disk  24   a . At the end of the actuation action by the user, the locking latch  28  now pivots back to the hold position due to the pre-tensioning thereof. Since in the process the safety catch  32  and the respective tooth  26  of the upper toothed disk  24   a  are no longer engaged, the toothed-disk arrangement  24  can now again rotate clockwise until it again comes into engagement between the locking catch  30  and the respective next of the teeth 1-10 of the lower toothed disk  24   b.    
       FIGS. 2-6  illustrate such a release procedure in step-by-step fashion with the aid of a second embodiment of a step shifter  20 ′ according to the invention. The toothed-disk arrangement  24 ′ shown there only consists of a single toothed disk  24 ′ that comprises a number of teeth 1-9 and A-E, this number being higher than the number of actuation positions of the toothed-disk arrangement. The second embodiment of a hold and release mechanism  29 ′ according to the invention shown in  FIGS. 2-8  shows the interaction of the toothed-disk arrangement  24 ′ and the locking latch  28 ′. Here, the toothed-disk arrangement  24 ′ has a total of 14 teeth 1-9 and A-E, all of which are located in a single plane that lies perpendicular to the axis of rotation X of the toothed-disk arrangement  24 ′ directed inward into the plane of the drawing. Accordingly, the locking latch  28 ′ is also designed such that the locking catch  30 ′ and the safety catch  32 ′ thereof lie precisely in this plane. In contrast to the first embodiment shown in  FIG. 1 , in this second embodiment a portion of the teeth 1-9 and A-E of the toothed-disk arrangement  24 ′ can come into engagement with either the locking catch  30 ′ or the safety catch  32 ′ of the locking latch  28 ′ depending on the rotational position of the toothed-disk arrangement  24 ′ and the pivot position of the locking latch  28 ′. 
       FIGS. 2-6  illustrate a release procedure that corresponds to a transition from a fourth to a fifth actuation position. In  FIG. 2 , the tooth 4 of the toothed-disk arrangement  24 ′ and the locking catch  30 ′ of the locking latch  28 ′, which is in its hold position, are engaged. Since the toothed-disk arrangement  24 ′ is biased in the clockwise direction and the locking latch  28 ′ is biased toward the hold position shown, the toothed-disk arrangement  24 ′ is fixed in this actuation position. 
       FIG. 3  now shows the beginning of a release actuation of the locking latch  28 ′, which is triggered by an upward push on the actuation lever  40  by a user. This actuation lever  40  acts on the engaging lug  34  of the locking latch  28 ′, pivots it from the hold position thereof in the direction of the safety position thereof. In the pivot position of the locking latch  28 ′ shown in  FIG. 3 , tooth 4 and the locking catch  30 ′ have just disengaged outward and the toothed-disk arrangement  24 ′ begins to rotate due to the pre-tensioning thereof in the clockwise direction. 
     This rotation continues until the engagement shown in  FIG. 4  occurs between the safety catch  32 ′ and tooth E of the toothed-disk arrangement  24 ′. When the user stops exerting pressure on the actuation lever  40 , the locking latch  28 ′ begins to pivot back to the hold position thereof as shown in  FIG. 5 . In the process, the safety catch  32 ′ of locking latch  28 ′ and tooth E of toothed-disk arrangement  24 ′ disengage. Now, the toothed-disk arrangement  24 ′ begins to further rotate clockwise again. 
     Finally, shown in  FIG. 6  is the state in which tooth 5 of toothed-disk arrangement  24 ′ and the locking catch  30 ′ of locking latch  28 ′ engage with one another. In this state, the toothed-disk arrangement  24 ′ is held in the fifth actuation position thereof by the locking latch  28 ′. 
     Shown in  FIG. 7  is a state of the step shifter in which the toothed-disk arrangement  24 ′ is held in the ninth actuation position thereof. It can be seen that by selecting the number of teeth 1-9 and A-E of the toothed-disk arrangement  24 ′ as seen counterclockwise from tooth A, there is no tooth available any longer at the toothed-disk arrangement  24 ′ that could engage with the safety catch  32 ′ of the locking latch  28 ′ when another release procedure is initiated. In this way, up-shifting from the ninth to the tenth actuation position is achieved without the toothed-disk arrangement  24 ′ being intermediate held any further. 
     The tenth actuation position, i.e. the actuation position of maximum pull-out, can be defined by an internal stop in the step shifter for the toothed disk or for the cable take-up device, which is designed as a winding drum, for example. In contrast, however, it is preferred for the actuation position of maximum pull-out to be defined non-specifically by way of the device actuated using the step shifter, namely an actuation position of the device corresponding to the state of maximum cable pull-out, and for example by an adjustable stop of the device, for example a derailleur device of a bicycle derailleur. 
     In this regard, it must be explained that the exemplary embodiments described above assume that the actuation cable is biased in the pull-out direction by the device to be actuated so that the reference cable is pulled out based on this tension exerted by the actuated device with the aid of the spring element mentioned. 
     The actuation position to be reached when the toothed-disk arrangement  24 ′ is released from the ninth actuation position consequently corresponds to the actuation position of maximum pull-out of the step shifter  20 ′. This actuation position of maximum pull-out is shown in  FIG. 8 . The cam element  42  which is rigidly connected to and above the toothed-disk arrangement  24 ′ can be seen here. This element was not shown in the previous figures for reasons of clarity. In the actuation position of maximum pull-out shown in  FIG. 8 , engagement occurs between the cam element  42  and a fixing edge  44  that extends upward at the end of the locking latch  28 ′ which likewise contains the locking catch  30 ′. The engagement between the cam element  42  and the fixing edge  44  causes the locking latch  28 ′ to not be able to pivot back to the hold position thereof in this actuation position of the toothed-disk arrangement  24 ′. Thus, this actuation position is not defined by an engagement of the locking latch  28 ′ with the toothed-disk arrangement  24 ′, but can be finely adjusted using the end stop outside the step shifter  20 ′ mentioned previously. 
     To clarify a possible arrangement of toothed disk  24 ′, cam element  42  and cable take-up device  46 , further reference is made to  FIG. 9 . Shown here is the assembly made up of the toothed disk  24 ′ and the cable take-up device  46  near the teeth 7-9, E and D as shown from the side. As can be seen, the cam element is rigidly attached to the cable up-take device  46  above the toothed disk  24 ′ as seen from the base plate  22  and essentially spans the teeth 8, 9 and E of toothed disk  24 ′. Since the cam element  42  does not extend into the plane of the toothed disk  24 ′, there is no engagement occurring between the cam element  42  and the locking catch  30 ′ or the safety catch  32 ′ of the locking latch  28 ′ independent of the rotational position of the toothed disk  24 ′ relative to the locking latch, which is not shown in  FIG. 9 . The cam element can consequently only engage with the fixing edge  44  in the rotational position of toothed disk  24 ′ shown in  FIG. 8 . 
     Finally,  FIG. 10  shows the system according to a useful exemplary embodiment in general schematic representation, the system comprising the step shifter  20 , actuation cable  48  and device  50  that can be actuated by the step shifter. In this system, the actuatable device  50  can in particular be a bicycle chain switching system, wherein the motion of a derailleur actuatable by an actuation cable  48  is coupled to an actuation element  52  in which the actuation cable  48  (for example the wire cable of a Bowden cable) is held. The chain switching system  50  further comprises another spring element  54  that pre-tensions or biases the actuation element  52  which can pivot about pivot axis S, thereby pre-tensioning the actuation cable  48  as well to an actuation position of maximum pull-out of the actuation cable  48 . For fine adjustment of this actuation position of maximum pull-out and thereby an actuation position of the derailleur, an end stop  56  is provided in the actuatable device  50  along an axis Z. 
     What is provided is a hold and release mechanism for holding and releasing a cable take-up device of a step shifter. The device includes a toothed disk arrangement that is part of the cable take-up device as a single piece or is connected or can be connected rigidly thereto and can rotate therewith about a first axis (X). The toothed disk arrangement includes a plurality of teeth at the outer periphery thereof. An adjustable locking latch is preferably pivotable about a second axis (Y). The latch, in a first position when the toothed-disk arrangement is located in various first rotational positions, in particular in a first rotational position, engaging by way of a locking catch with a tooth from the plurality of teeth that acts as a locking tooth associated with the respective first rotational position, to hold or stop the toothed disk arrangement and thereby the cable take-up device in the respective first rotational position. The latch also, in a second position when the toothed-disk arrangement is located in various second rotational positions, in particular in a second rotational position, engaging by way of a safety catch with a tooth from the plurality of teeth that acts as a safety tooth associated with the respective second rotational position, to hold or stop the toothed disk arrangement and thereby the cable take-up device in the respective second rotational position. The first rotational positions correspond to the actuation positions of the actuation cable or a subset of the actuation positions and the second rotational positions correspond to intermediate positions of the actuation cable when the actuation cable is transitioned between adjacent actuation positions through release of the actuation cable. 
     Whilst the invention has been described with regard to the associated embodiments, it can be seen that various amendments can be undertaken within the scope of protection of the inventive concept. Accordingly the invention is not limited by the disclosed embodiments, but has the entire scope of protection of the following claims.