NL2025786B1

NL2025786B1 - Clutch or brake system for a torque transmission

Info

Publication number: NL2025786B1
Application number: NL2025786A
Authority: NL
Inventors: Marie Van Druten Roëll
Original assignee: Classified Cycling Bv
Priority date: 2020-06-08
Filing date: 2020-06-08
Publication date: 2022-01-28

Abstract

A clutch or brake system for a torque transmission. The clutch or brake system includes a first rotatable unit connectable to an input or output, including at least one first abutment surface and a second rotatable unit connectable to an output or input, respectively, including at least one second abutment surface arranged for selectively engaging the first abutment surface. The first and second abutment 10 surfaces are adapted to each other so as to allow disengaging under load. The system includes a third rotatable unit including at least one retaining member, the third unit being arranged for selectively being in a first rotational position or a second rotational position relative to the second rotatable unit, wherein the at least one retaining member in the first rotational position locks the at least one second 15 abutment surface for rotationally coupling the second rotatable unit to the first rotatable unit. Fig. 1

Description

P127133NL00 Title: Clutch or brake system for a torque transmission

FIELD OF THE INVENTION The invention relates to a clutch or brake system for a torque transmission having an input arranged for connection to a drive source, and an output arranged for connection to a load.

BACKGROUND TO THE INVENTION Transmission systems, e.g. for vehicles, windmills etc., are known. In bicycles, especially racing bicycles, the transmission system traditionally includes a front derailleur and a rear derailleur, for shifting gears of the transmission system. An alternative to derailleurs is formed by gear hubs, where shifting of gears is accommodated by a gear shifting mechanism inside the, generally rear, wheel hub. A hybrid form is known where a gear hub torque transmission having at least two selectable gear ratios is coupled between the rear wheel hub and the rear sprocket. Herein the rear sprocket can include a plurality of gear wheels, selectable through a rear derailleur. Here the gear hub can take the place of a front derailleur. Such gear hub gear shifting mechanisms can include one or more planetary gear sets. The planetary gear includes at least three rotational members, such as a sun gear, a planet carrier and a ring gear. A clutch or brake system can be used for selectively coupling two of the rotational members, e.g. the planet carrier and the ring gear. When coupled, the hub gear shifting mechanism operates according to a first gear ratio. When decoupled, the hub gear shifting mechanism operates according to a second gear ratio.

SUMMARY OF THE INVENTION It is an object to provide a clutch or brake system for a torque transmission which is cost-effective, can be manufactured with a small size, is easy to operate and/or is durable. Alternatively, or additionally, it is an object to provide a clutch or brake system for a torque transmission which can be operated under load, e.g. while pedaling. Alternatively, or additionally, it is an object to provide a clutch or brake system for a torque transmission which can be operated for coupling and for decoupling under load, e.g. while pedaling. Alternatively, or additionally, it is an object to provide a clutch or brake system for a torque transmission which can be operated both for upshifting and for downshifting under load, e.g. while pedaling.

More in general it is an object to provide an improved clutch or brake system for a torque transmission, or at least an alternative clutch or brake system for a torque transmission.

Optionally, it is an object to provide a clutch or brake system in which lockup can be prevented or at least the risk of lockup can be diminished.

According to an aspect is provided a clutch or brake system for a torque transmission.

Such clutch or brake system can be used in a vehicle, such as a bicycle or car, a windmill, or the like.

The clutch or brake system has an input arranged for connection to a drive source, and an output arranged for connection to a load.

Preferably, the clutch or brake system is operable under load between the input and the output.

More preferably, the clutch or brake system is operable under load between the input and the output both when coupling and when decoupling.

Preferably, the clutch or brake system is operable under load between the input and the output both during upshift and downshift of the torque transmission.

The clutch or brake system includes a first rotatable unit, e.g. a housing, connectable to the input.

The clutch or brake system includes a second rotatable unit connectable to the output.

It is also possible that the first rotatable unit is connectable to the output and the second rotatable unit is connectable to the input.

The first rotatable unit includes at least one first abutment surface.

The second rotatable unit includes at least one second abutment surface arranged for selectively engaging the first abutment surface.

The first and second abutment surfaces are adapted to each other so as to allow disengaging under load, e.g. so as to disengage under load, e.g. in two directions.

The clutch or brake system includes a third rotatable unit.

The third rotatable unit can be arranged for co-rotating with the second rotatable unit.

The third rotatable unit includes at least one retaining member.

The third rotatable unit is arranged for selectively being in a first position or a second position relative to the second rotatable unit.

It will be appreciated that the first position can be a first rotational and/or axial position, and the second position can be a second, different, rotational and/or axial position.

The at least one retaining member in the first position locks the at least one second abutment surface, preferably in engagement with the at least one first abutment surface, for rotationally coupling the second rotatable unit to the first rotatable unit. The at least one retaining member in the second position releases the at least one second abutment surface, preferably for disengagement of the at least one first abutment surface, for decoupling the second rotatable unit from the first rotatable unit.

Hence, while the first and second abutment surfaces are adapted to each other so as to allow disengaging under load, or to disengage under load, the relative positioning of the second and third rotatable units can in the first position lock the at least one second abutment surface in engagement with the at least one first abutment surface, and in the second position release the at least one second abutment surface for disengagement of the at least one first abutment surface. Hence, in the first position, the second rotatable unit can be rotationally coupled to the first rotatable unit, and in the second position the second rotatable unit can be decoupled from the first rotatable unit.

The third rotatable unit includes at least two actuation members arranged for moving the third rotatable unit from a first position to a second position or from a second position to a first position relative to the second rotatable unit.

The clutch or brake system includes a fourth unit including a selector, the selector being arranged for selectively being in a gripping or non-gripping mode. The selector in the gripping mode is arranged for gripping at least one of the at least two actuation members for rotating the third rotatable unit from the first position to the second position or from the second position to the first position relative to the second rotatable unit. 'The selector in the non-gripping mode is arranged for not engaging the at least two actuation members. The selector in the non-gripping mode can allow the third rotatable unit to freely rotate with the second rotatable unit.

The second rotatable unit includes a retractor member arranged for moving the at least two actuation members out of engagement with the selector. The at least one second abutment surface and at least one of the at least two actuation members are angularly positioned such that when the at least one second abutment surface just engages the first abutment surface the at least one of the at least two actuation members still engages, e.g. lies on top of, the retractor member.

Thus a simple and efficient clutch or brake system can be provided, wherein in particular a risk of lock-up of said system during use is reduced while above-mentioned advantages are maintained.

Optionally, the at least one second abutment surface is a gripping member arranged for radially moving, e.g. pivoting, in and out of engagement with the at least one first abutment surface.

Optionally, the at least one second abutment surface and at least one of the at least two actuation members are angularly positioned such that when the at least one gripping member engages a ramp of the at least one retaining member and the at least one second abutment surface of the gripping member engages or is immediately adjacent a radially inner surface of the first unit, the other of the at least two the actuation members is just moved out of engagement with the selector by the retractor tab.

Optionally, the at least two actuation members are hingedly connected to the third unit.

Optionally, the third unit has predefined angular indexing positions with respect to the second unit, such as six predefined indexing Optionally, the angular indexing positions are such that in at least one of the indexing positions the gripping member is positioned on the top of the retaining member.

Optionally, the angular indexing positions are such that in at least one of the indexing positions the gripping member is positioned on a leading ramp of the retaining member.

Optionally, the third rotatable unit includes a first body and a second body, wherein the first body includes the at least one retaining member, and the second body includes at least one of the at least two actuation members.

Optionally, the first body is rotationally resiliently coupled to the second body.

Optionally, a first force biasing the at least two actuation members towards the fourth unit is smaller than a second force biasing the first body relative to the second body.

Optionally, the first body includes the at least one retaining member, and the second body includes two actuation members.

Optionally, the at least one second abutment surface and at least one of the at least two actuation members are angularly positioned such that when the at 5 least one gripping member engages a ramp of the at least one retaining member and the at least one second abutment surface of the gripping member engages or is immediately adjacent a radially inner surface of the first unit, one of the at least two the actuation members is biased against a trailing side of the retractor member, in particular pushed by a tangential spring force applied by a resilient element arranged between the first and the second body of the third unit.

Optionally, the first body includes the at least one retaining member and one of the at least two actuation members, and the second body includes another of the at least two actuation members.

Optionally, the third rotatable unit is arranged for co-rotating with the second rotatable unit, and the system is arranged for temporarily changing rotation speed of the third rotatable unit relative to the second rotatable unit, e.g. by temporarily speeding up, braking or halting the second and/or third rotatable unit, for rotating from the first position to the second position, or from the second position to the first position.

Optionally, the third rotatable unit is rotatable relative to the second rotatable unit. Optionally a rotation angle of the third rotatable unit relative to the second rotatable unit is more than 360 degrees. Optionally a rotation angle of the third rotatable unit relative to the second rotatable unit is unlimited. The clutch or brake system can be free from stop means limiting the rotation angle of the third rotatable unit relative to the second rotatable unit.

Optionally, the third rotatable unit is arranged to be rotated relative to the second rotatable unit from the first position to the second position, and from the second position to the first position in one and the same rotational direction. The third rotatable unit can be rotated relative to the second rotatable unit in a continued forward rotation for being moved from the first position to the second position, and from the second position to the first position. The third rotatable unit can be rotated relative to the second rotatable unit in a continued rearward rotation for being moved from the first position to the second position, and from the second position to the first position. Optionally, the third rotatable unit is arranged for selectively being in one of a plurality of first or second positions relative to the second rotatable unit.

The third rotatable unit in each of the first positions of the plurality of first positions locks the at least one second abutment surface in engagement with the at least one first abutment surface for rotationally coupling the second rotatable unit to the first rotatable unit. The third rotatable unit in each of the second positions of the plurality of second positions releases the at least one second abutment surface for disengagement of the at least one first abutment surface for decoupling the second rotatable unit from the first rotatable unit. The third rotatable unit can be arranged to be rotated relative to the second rotatable unit from a first first position to a first second position, and from the first second position to a second first position in one and the same rotational direction. The third rotatable unit can be arranged to be rotated relative to the second rotatable unit from the second first position to a second second position, and from the second second position to a third first position (or to a third first position) in the same one and the same rotational direction. The first positions of the plurality of first positions can e.g. be equally spaced around the perimeter of the second rotatable unit. The second positions of the plurality of second positions can e.g. be equally spaced around the perimeter of the second rotatable unit. The first positions and second positions can be alternatingly and preferably equally spaced around the perimeter of the second rotatable unit. For example, three first positions and three second positions are alternatingly spaced at 60 degrees around the perimeter of the second rotatable unit.

Optionally, the second and third rotatable units are free from biasing force relative to each other, such that the third rotatable unit is not forced into a first or second position relative to the second rotatable unit by a force, such as a spring force.

Optionally, the third rotatable unit includes at least one retainer, and the second rotatable unit includes at least one notch, or wherein the second rotatable unit includes at least one retainer, and the third rotatable unit includes at least one notch, for indexing the second rotatable unit relative to the third rotatable unit by resilient engagement of at least one of the at least one retainers in at least one of the at least one notches. Hence, the third rotatable unit can assume a defined angular position relative to the second rotatable unit.

Optionally, the retainer is hingedly connected to the third rotatable unit, such as for pivoting motion around a pivot axis parallel to the rotational axis of the third rotational unit.

Optionally, the retainer is formed as a pin slidable along an axis parallel to the rotational axis of the third rotational unit. The notch can be an axial depression. The pin can be slidably housed in the third rotational unit, and biased towards the second rotational unit, the second rotational unit having at least one axial depression. The pin can be slidably housed in the second rotational unit, and biased towards the third rotational unit, the third rotational unit having at least one axial depression.

A first force biasing the slidable pin towards the notch can be smaller than a second force biasing the first body relative to the second body.

Optionally, the engagement or disengagement of the second abutment surface with the at least one first abutment surface is independent of input torque and/or rotation speed, but relies only on the second and third rotatable units being in the first or second relative positions.

Optionally, the at least one second abutment surface of the second rotatable unit is hingedly connected to the remainder of the second rotatable unit. Optionally, the at least one second abutment surface of the second rotatable unit is hingedly connected to the remainder of the second rotatable unit so as to have a single pivot axis.

Optionally, the selector includes a groove including a first partial groove and a second partial groove. In gripping mode the partial grooves allow, e.g. align for, engaging the at least one actuation member. In non-gripping mode the partial grooves allow, e.g. are out of alignment for, preventing engagement of the at least one actuation member.

Optionally, the third rotatable body includes two actuation members, optionally arranged such that when the first actuation member is biased into contact with the selector, the second actuation member is maintained at a distance from, e.g. non-engaged by, the selector and vice versa. Optionally, the selector is arranged to be in a first mode or in a second mode. In the first mode the selector is in gripping mode for the first actuation member and in non-gripping mode for the second actuation member. In the second mode the selector is in non-gripping mode for the first actuation member and in gripping mode for the second actuation member.

Optionally, the selector includes a groove including a first partial groove, a second partial groove and a third partial groove. In the first mode the first and second partial grooves allow, e.g. align for, gripping the first actuation member and optionally for not engaging the second actuation member, and in the second mode the second and third grooves allow, e.g. align for, gripping the second actuation member and optionally for not engaging the first actuation member.

Optionally, the first partial groove, the second partial groove and the third partial groove extend on a cylindrical surface of the fourth unit in a direction substantially parallel to an axis of the cylindrical surface.

Optionally, the second partial groove and the third partial groove are arranged to be moved, e.g. relative to the first partial groove, e.g. displaced tangentially. Optionally, the second and third partial groove are arranged to be moved, e.g. simultaneously, in opposite directions.

Optionally, the second partial groove is arranged for moving in the same direction as the first actuation member when the second partial groove moves from the non-gripping mode to the gripping mode for the first actuation member, and the third partial groove is arranged for moving in the same direction as the second actuation member when the third partial groove moves from the non-gripping mode to the gripping mode for the second actuation member. Hence, forces on the selector are minimized, and symmetrical for both actuation members.

Optionally, the at least one actuation member is arranged for radially moving, e.g. pivoting, in and out of engagement with the fourth unit.

Optionally, the first and/or second abutment surface is biased to disengage. Hence the default for the first and second abutment surfaces is a disengaged mode. The relative position of the third and second rotatable units then determined whether or not the first and second abutment surfaces are engaged or disengaged.

Optionally, the clutch or brake system includes a plurality of first and/or second abutment surfaces, e.g. distributed along a perimeter of the first and/or second rotatable units, respectively. Optionally, the first and/or second abutment surfaces are distributed substantially uniformly along the perimeter of the first and/or second rotatable units, respectively. Optionally the number of first abutment surfaces is equal to the number of second abutment surfaces.

Optionally, the clutch or brake system includes a plurality of retaining members.

Optionally, the first, second, third, and/or fourth unit are coaxial. Optionally, the fourth unit is positioned at least partially within the third rotatable unit, and/or the third rotatable unit is at least partially positioned within the second rotatable unit, and/or the second rotatable unit is at least partially positioned within the first rotatable unit.

According to an aspect is provided a torque transmission, including a clutch or brake system, for instance as described herein, and a planetary gear. The clutch or brake system can be arranged in the torque transmission so as to selectively couple two of a sun gear, a planet carrier and a ring gear of the planetary gear. Optionally, the clutch or brake system is arranged in the torque transmission so as to selectively couple the planet carrier and the ring gear.

Optionally, the ring gear is rotationally fixed to the first rotational unit and the planet carrier is rotationally fixed to the second rotational unit, or the ring gear is rotationally fixed to the second rotational unit and the planet carrier is rotationally fixed to the first rotational unit.

Optionally, the sun gear is connected to the fourth unit via a one way bearing.

Optionally, the one way bearing is arranged to allow rotation of the sun gear in forward direction with respect to the fourth unit.

Optionally, the one way bearing is arranged to allow rotation of the sun gear with respect to the fourth unit with minimum friction and/or minimum noise.

Optionally, the one way bearing is arranged to loek rotation of the sun gear in backward direction with respect to the fourth unit.

Optionally, the one way bearing is arranged to allow a torque of up to 118Nm, and/or prevent slip.

Optionally, the one way bearing is a radial one-way bearing with rollers or with ratchet teeth.

Optionally, the one way bearing is an axial one-way bearing with rollers or with ratchet teeth.

According to an aspect is provided a wheel axle assembly, such as a bicycle wheel axle assembly, including the torque transmission.

Optionally, an axle of the wheel axle assembly is rotationally fixed to the fourth unit.

Optionally, a driver body is connected to the first rotational unit or the second rotational unit.

The wheel axle assembly can be arranged for receiving a cassette having a plurality of gear wheels.

According to an aspect is provided a bicycle wheel hub including a clutch or brake system as described herein. The bicycle wheel hub can include a torque transmission, as described. Optionally, the wheel hub is arranged for receiving a cassette having a plurality of gear wheels.

According to an aspect is provided a bicycle including a clutch or brake system as described herein. The bicycle can include a torque transmission, including a clutch or brake system as described herein and a planetary gear. The clutch or brake system can be arranged in the torque transmission so as to selectively couple two of the sun gear, the planet carrier and the ring gear. Optionally, the clutch or brake system is arranged in the torque transmission so as to selectively couple the planet carrier and the ring gear. Optionally, the torque transmission is included in a rear wheel hub of the bicycle. Optionally, a rear cassette having a plurality of gear wheels is attached to the rear wheel hub. The bicycle can include a rear derailleur for selecting one of the plurality of gear wheels of the rear pinion. Optionally, the bicycle includes one single front pinion. In such case, the torque transmission can emulate functioning of a front derailleur.

According to an aspect is provided a method for operating a clutch or brake system for a torque transmission. Such method can be practiced in a vehicle, such as a bicycle or car, a windmill or the like. The clutch or brake system has an input arranged for connection to a drive source, and an output arranged for connection to a load.

The method includes providing a clutch or brake system as described herein.

The method includes rotating the third rotatable unit relative to the second rotatable unit from the first rotational position to the second rotational position for disengaging the clutch or brake system, and rotating the third rotatable unit relative to the second rotatable unit from the second rotational position to the first rotational position for engaging the clutch or brake system.

Optionally, the method includes having the third rotatable unit co- rotate with the second rotatable unit, and temporarily changing rotation speed of the third rotatable unit relative to the second rotatable unit, e.g. by temporarily speeding up, braking or halting the second and/or third rotatable unit, for rotating the third rotatable unit from the first position to the second position, or from the second position to the first position, relative to the second rotatable unit.

Optionally, the method includes automatically resuming co-rotation of the third rotatable unit with the second rotatable unit after the third rotatable unit has been rotated from the first rotational position to the second rotational position or vice versa.

According to an aspect is provided a method for operating a clutch or brake system for a torque transmission.

Such method can be practiced in a vehicle, such as a bicycle or car, a windmill or the like.

The method includes providing a clutch or brake system as deseribed herein.

The method includes temporarily changing rotation speed of the third rotatable unit relative to the second rotatable unit, e.g. by temporarily speeding up, braking or halting the second and/or third rotatable unit, for rotating the third rotatable unit from the first rotational position to the second rotational position, or from the second rotational position to the first rotational position, relative to the second rotatable unit.

Optionally, the method includes rotating the third rotatable unit from the first rotational position to the second rotational position and from the second rotational position to the first rotational position in one and the same rotational direction.

Optionally, the method includes with the selector in the gripping mode gripping at least one of the at least two actuation members for rotating the third rotatable unit from the first rotational position to the second rotational position or from the second rotational position to the first rotational position relative to the second rotatable unit, and with the selector in the non-gripping mode not engaging the at least one of the at least two actuation members. The selector in the non- gripping mode can allow the third rotatable unit to freely rotate with the second rotatable unit.

According to an aspect is provided a method for operating a clutch or brake system for a torque transmission. Such method can be practiced in a vehicle, such as a bicycle or car, a windmill or the like. The clutch or brake system has an input arranged for connection to a drive source, and an output arranged for connection to a load. Preferably, the clutch or brake system is operable under load between the input and the output. More preferably, the clutch or brake system is operable under load between the input and the output both when coupling and when decoupling. Preferably, the clutch or brake system is operable under load between the input and the output both during upshift and downshift of the torque transmission. The method includes providing a clutch or brake system as described herein. The method includes with the selector in the gripping mode gripping at least one of the at least two actuation members for rotating the third rotatable unit from a first rotational position (e.g. the first position or a first position of the plurality of first positions) to a second rotational position (e.g. the second position or a second position of the plurality of second positions) or from a second rotational position (e.g. the second position or a second position of the plurality of second positions) to a first rotational position (e.g. the first position or a first position of the plurality of first positions) relative to the second rotatable unit; and with the selector in the non-gripping mode not engaging the at least one of the at least two actuation members. The selector in the non-gripping mode can allow the third rotatable unit to freely rotate with the second rotatable unit.

Optionally, the method includes in the first rotational position locking the at least one second abutment surface for rotationally coupling the second rotatable unit to the first rotatable unit, and in the second rotational position releasing the at least one second abutment surface for decoupling the second rotatable unit from the first rotatable unit.

Optionally, the actuation member is biased into contact with the selector.

Optionally, the method includes, e.g. actively, moving the at least one of the at least two actuation members out of engagement with the selector after the third rotatable unit has been rotated from the first rotational position to the second rotational position, or from the second rotational position to the first rotational position.

Optionally, the selector includes a groove including a first partial groove and a second partial groove, and the method includes in gripping mode allowing, e.g. aligning, the partial grooves to engage the at least one actuation member, and in non-gripping mode allowing, e.g. dis-aligning, the partial grooves to prevent engagement of the at least one actuation member.

Optionally, the third rotatable unit includes two actuation members, optionally arranged such that when the first actuation member is in contact with the selector, the second actuation member maintained at a distance from the selector and vice versa, and the method includes selectively setting the selector in a first mode or in a second mode, wherein in the first mode the selector is in gripping mode for the first actuation member and in non-gripping mode for the second actuation member, and in the second mode the selector is in non-gripping mode for the first actuation member and in gripping mode for the second actuation member.

Optionally, the selector includes a groove including a first partial groove, a second partial groove and a third partial groove, wherein in the first mode the first and second partial grooves allow, e.g. align for, gripping the first actuation member and optionally not engaging the second actuation member, and in the second mode the second and third grooves allow, e.g. align for, gripping the second actuation member and optionally not engaging the first actuation member.

Optionally, the method includes moving the second and third partial grooves, e.g. simultaneously, in opposite directions.

Optionally, the method includes moving the second partial groove in the same direction as the first actuation member when the second partial groove moves from the non-gripping mode to the gripping mode for the first actuation member, and moving the third partial groove in the same direction as the second actuation member when the third partial groove moves from the non-gripping mode to the gripping mode for the second actuation member.

It will be appreciated that any one or more of the above aspects, features and options can be combined. It will be appreciated that any one of the options described in view of one of the aspects can be applied equally to any of the other aspects. It will also be clear that all aspects, features and options described in view of the clutch or brake system apply equally to the method, and vice versa.

BRIEF DESCRIPTION OF THE DRAWING The invention will further be elucidated on the basis of exemplary embodiments which are represented in a drawing. The exemplary embodiments are given by way of non-limitative illustration. It is noted that the figures are only schematic representations of embodiments of the invention that are given by way of non-limiting example.

In the drawing: Fig. 1 shows an example of a clutch or brake system; Fig. 2 shows an example of a clutch or brake system; Fig. 3 shows an example of a clutch or brake system; Fig. 4a, 4b and 4c show an example of a clutch or brake system; Fig. 5 shows an example of a clutch or brake system; Fig. 6 shows an example of a clutch or brake system; Fig. 7 shows an example of a clutch or brake system; Figs. 8a-8d show an example of gripping and ungripping the actuation members;

Figs. 9a-9c show schematic examples of a torque transmission; Figs. 10a-10c¢ show schematic examples of a torque transmission; Fig. 11 shows an example of a wheel axle assembly; Fig. 12 shows an example of a clutch or brake system; Fig. 13a shows an example of a clutch or brake system; Fig. 13b shows an example of a clutch or brake system; Fig. 14a shows an example of a clutch or brake system; Fig. 14b shows an example of a clutch or brake system; Fig. 15a shows a detail of a clutch or brake system of Figs. 12-14b; Fig. 15b shows a detail of a clutch or brake system of Figs. 12-14b; and Fig. 15c shows a detail of a clutch or brake system of Figs. 12-14b.

DETAILED DESCRIPTION Figures 1, 2 and 3 show an example of a clutch or brake system 1. The clutch or brake system 1 of this example is for use in a torque transmission of a bicycle, however, other fields of use can be envisioned. The clutch or brake system 1 has an input arranged for connection to a drive source, such as pedals or a chain/belt. The clutch or brake system has an output arranged for connection to a load, such as a rear wheel hub. The exemplary clutch or brake system 1 is operable under load between the input and the output, e.g. while pedaling. Hence, the clutch or brake system 1 can be coupled or decoupled under load. Here, the clutch or brake system is operable under load between the input and the output both during upshift and downshift of the torque transmission. The clutch or brake system in Figures 1, 2 and 3 includes a first rotatable unit 2. The first rotatable unit 2 is arranged to be connected to the input. Here, the first rotatable unit 2 is designed as a housing part of the clutch or brake system 1. The clutch or brake system 1 includes a second rotatable unit 4. The second rotatable unit 4 is arranged to be connected to the output. The first rotatable unit 2 includes at least one first abutment surface 6. In this example, the first rotatable unit 2 includes nine first abutment surfaces 6, here evenly distributed along the perimeter of the first rotatable unit 2 at 40 degrees mutual spacing. The second rotatable unit 4 includes at least one second abutment surface

8. In this example, the second rotatable unit 4 includes three second abutment surfaces 8, here evenly distributed along the perimeter of the second rotatable unit 4 at 120 degrees mutual spacing. It will be appreciated that in this example the second rotatable unit 4 includes a plurality of gripping members 4a, here embodied as separate parts hingedly connected to a body portion 4b of the second rotatable unit 4. In this example, the second abutments surfaces 8 are part of the gripping members 4a of the second rotatable unit 4. The second abutment surfaces 8, here the gripping members 4a, are each arranged for selectively engaging one of the first abutment surfaces 6. In the example of Figure 1 it can be seen that the first and second abutment surfaces are oriented at an angle relative to a radial direction of the first and second rotatable units, respectively. This allows the first and second abutment surfaces are to disengaging under load. In this example, the second rotatable unit 4 includes resilient members 4c, here helical springs, arranged so as to bias the second abutment surfaces 8 out of engagement with the first abutment surfaces 6.

The clutch or brake system 1 in Figures 1, 2 and 3 includes a third rotatable unit 10. The third rotatable unit 10 is arranged for co-rotating with the second rotatable unit 4. That is, in use, when the output is rotating (e.g. when the driven wheel of the bicycle is rotating), i.e. when the second rotatable unit 4 is rotating, the third rotatable unit 10 generally co-rotates with the second rotatable unit 4.

The third rotatable unit 10 includes at least one retaining member 12. In this example, the third rotatable unit 10 includes three retaining members 12, here evenly distributed along the perimeter of the third rotatable unit 10 at 120 degrees mutual spacing. The third rotatable unit 10 is arranged for selectively being in a first position (see Figure 1) or a second position (see Figure 3) relative to the second rotatable unit 4. It will be appreciated that in this example the first position is a first rotational position, and the second position is a second, different, rotational position.

In the first position (shown in Figure 1), the retaining members 12 are positioned rotationally aligned with, here under, cams 4d of the gripping members 4a. Thus, in the first position, the gripping members 4a are forced to be pivoted in a radially outer position. In the first position, the second abutment surfaces 8 are positioned to be touching or close to the first abutment surfaces 6. The presence of the retaining members 12 under the cams 4a prevents the second abutment surfaces from being pivoted radially inwards sufficiently to disengage from the first abutment surfaces 6. Hence, the retaining members 12 in the first position lock the second abutment surfaces 8 in engagement with the first abutment surfaces 6. As the second abutment surfaces 8 are locked in engagement with the first abutment surfaces 6, the second rotatable unit 4 is rotationally coupled to the first rotatable unit 2.

In the second position (shown in Figure 3), the retaining members 12 are positioned rotationally not aligned with, here out of the reach of, the cams 4d of the gripping members 4a. Thus, in the second position, the gripping members 4a are free to pivot to a radially inner position. In this example, the biasing force of the resilient members 4c pivots the second abutment surfaces 8 radially inwards sufficiently to disengage from the first abutment surfaces 6. As a result, the first rotatable unit 2 is free to rotate independently of the second rotatable unit 4. Thus, the second rotatable unit 4 is decoupled from the first rotatable unit 2.

Hence, while the first abutment surfaces 6 and second abutment surfaces 8 are adapted to each other so as to allow disengaging under load, or to disengage under load, the relative positioning of the second rotatable unit 4 and the third rotatable unit 10 can selectively in the first position lock the second abutment surfaces 8 in engagement with the first abutment surfaces 6, and in the second position release the second abutment surfaces 8 for disengagement from the first abutment surfaces 6. It will be appreciated that while the first rotatable unit 2 and second rotatable unit 4 are decoupled, rotating the third rotatable unit 10 from the first position to the second position relative to the second rotatable unit 4, will couple the first and second rotatable units. While the first rotatable unit 2 and second rotatable unit 4 are coupled, rotating the third rotatable unit 10 from the second position to the first position relative to the second rotatable unit 4, will decouple the first and second rotatable units.

Changing the position of the third rotatable unit 10 relative to the second rotatable unit 4 from the first position to the second position, or vice versa, can be performed in many different ways. Changing the position of the third rotatable unit 10 relative to the second rotatable unit 4 from the first position to the second position can be performed by rotating the third rotatable unit 10 relative to the second rotatable unit 4 in a forward direction, and changing the position of the third rotatable unit 10 relative to the second rotatable unit 4 from the second position to the first position can be performed by rotating the third rotatable unit 10 relative to the second rotatable unit 4 in an opposite, rearward direction. It is also possible to rotate the third rotatable unit 10 relative to the second rotatable unit 4 from the first position to the second position, and from the second position to the first position in one and the same rotational direction.

An actuator can be provided for rotating the third rotatable unit and/or the second rotatable unit from the first position to the second position, and/or from the second position to the first position.

In the example of Figures 1, 2 and 3, the third rotatable unit 10 is arranged for co-rotating with the second rotatable unit 4. Therefore, changing the position of the third rotatable unit 10 relative to the second rotatable unit 4 from the first position to the second position, or vice versa, can be performed by temporarily changing rotation speed of the third rotatable unit relative to the second rotatable unit, e.g. by temporarily speeding up, braking or halting the second and/or third rotatable unit, for rotating from the first position to the second position, or from the second position to the first position.

In the example of Figures 1, 2 and 3, the third rotatable unit 10 is freely rotatable relative to the second rotatable unit 4. There is no limit to the rotational displacement of the third rotatable unit 10 relative to the second rotatable unit 4. In this example, the third rotatable unit 10 is arranged for selectively being in one of a plurality of first positions or one of a plurality of second positions relative to the second rotatable unit. Each of the first positions of the plurality of first positions is defined by the third rotatable unit 10 being positioned to lock the second abutment surfaces 8 in engagement with the first abutment surfaces 6 for rotationally coupling the second rotatable unit 4 to the first rotatable unit 2. In this example there are three gripping members 4a and three retaining members 12, so there are three distinct first positions. Here, the three first positions are evenly distributed along the perimeter of the second rotatable unit 4 at 120 degrees mutual spacing. Each of the second positions of the plurality of second positions is defined by the third rotatable unit 10 being positioned to release the second abutment surfaces 8 from engagement with the first abutment surfaces 6 for rotationally decoupling the second rotatable unit 4 from the first rotatable unit 2. In this example there are three gripping members 4a and three retaining members 12, so there are three second positions. Here, the three second positions can be seen as evenly distributed along the perimeter of the second rotatable unit 4 at 120 degrees mutual spacing. It will be appreciated that the three first positions and three second positions are alternatingly placed along the perimeter of the second rotatable unit 4. For example, the three first positions and three second positions are alternatingly spaced at 60 degrees around the perimeter of the second rotatable unit.

Here, the third rotatable unit 10 can be rotated relative to the second rotatable unit 4 from a first first position to a first second position, from the first second position to a second first position, from the second first position to a second second position, from the second second position to a third first position, from the third first position to a third second position, and from the third second position to the first first position in one and the same rotational direction. The clutch or brake system 1 can be arranged for temporarily changing rotation speed of the third rotatable unit 10 relative to the second rotatable unit 4, e.g. by temporarily speeding up, braking or halting the second and/or third rotatable unit, for rotating from a first position (e.g. the first position or a first position of the plurality of first positions) to a second position (e.g. the second position or a second position of the plurality of second positions) or from a second position (e.g. the second position or a second position of the plurality of second positions) to a first position (e.g. the first position or a first position of the plurality of first positions). Hence, the second and third rotatable units can in a simple manner be rotated from a first position to a second position or vice versa.

Figures 4a, 4b, 4c and 5 show an example of a mechanism for moving the third rotatable unit 10 from a first position (e.g. the first position or a first position of the plurality of first positions) to a second position (e.g. the second position or a second position of the plurality of second positions) or from a second position (e.g. the second position or a second position of the plurality of second positions) to a first position (e.g. the first position or a first position of the plurality of first positions) relative to the second rotatable unit.

The third rotatable unit 10 includes at least one, here two, actuation member 10a arranged for moving the third rotatable unit 10 from a first position to a second position or from a second position to a first position relative to the second rotatable unit 4. The actuation members 10a are hingedly connected to a body portion 10b of the third rotatable unit 10. In this example, the body portion 10b of the third rotatable unit 10 includes an first body portion 10b1 and a second body portion 10b2. The first body portion 10b1 hingedly receives the actuation members 10a. The second body portion 10b2 includes the retaining members 12. The first body portion 10b1 is rotatable relative to the second body portion 10b2, here over an angular stroke S. The first and second body portions 10b1, 10b2 are biased in abutment with a resilient element 10c, here a tension spring. This allows the first and second body portions to rotate relative to each other. For example, when the retaining member 12 can not yet push the gripping member 4a radially outwardly in abutment with the first abutment surface 6 the resilient element 10c allows the first body portion 10b1 to rotate relative to the first rotatable unit 2 while the second body portion 10b2 does not rotate relative to the first rotatable unit 2.

In Figures 4a, 4b, 4c and 5 the clutch or brake system 1 further includes a, here non-rotatable, fourth unit 16. The fourth unit 16 can be arranged to be non- rotatably mounted to a frame of the bicycle. The fourth unit 16 is further shown in Figures 6 and 7. The fourth unit 16 includes a selector 18. The selector 18 is arranged for selectively being in a gripping or non-gripping mode.

As shown in Figures 4a-7, here the third rotatable body 10 includes two actuation members 10a. In this example, the actuation members 10a are biased towards the fourth unit 16 by resilient elements 10d, here helical springs. In this example, the second rotatable unit 4 includes three retractor members 4e. the retractor members 4e co-rotate with the body portion 4b of the second rotatable unit 4. The retractor members 4e can e.g. be fixedly connected to, or integral with, the body portion 4b. As can be seen in Figure 4a, one of the retractor members 4e, here 4e1, allows a first actuation member 10al to engage the fourth unit 16, while another one of the retractor members 4e, here 4e3, prevents a second actuation member 10a2 to engage the fourth unit 16. Hence, when the first actuation member 10al is biased into contact with the selector 18, the second actuation member 10a2 is maintained at a distance from, e.g. non-engaged by, the selector 18, and vice versa.

As shown in Figures 6 and 7, in this example the selector 18 includes a groove 20. In this example, the groove 20 includes a first partial groove 20a, a second partial groove 20b and a third partial groove 20c. In a first mode the first partial groove 20a and second partial groove 20b align as shown in Figures 6 and 7. It is noted that in this first mode the third partial groove 20c does not align with the first partial groove 20a. In a second mode the first partial groove 20a and third partial groove 20c align. It is noted that in this second mode the second partial groove 20b does not align with the first partial groove 20a. As can be seen in Figure 6, the first and second partial grooves 20a, 20b aligning, allows the first actuation member 10al to enter into the first partial groove 20a, as can also be seen in Figure 4a. It will be noted that in this example the shape of the first actuation member 10al, requires the first partial groove 20a and the second partial groove 20b to align for allowing the first actuation member 10al to enter the first partial groove 20a. The first partial groove 20a then supports the first actuation member 1041, allowing a force to be guided from the fourth unit 16 via the first actuation member 10al to the third rotatable unit 10. As a result, the third rotatable unit 10 will be halted, and when, in use, the second rotatable unit 4 will remain rotating, the third rotatable unit 10 will be rotated relative to the second rotatable unit 4. When the second rotatable unit 4 has rotated over approximately 60 degrees after gripping of the first actuation member 10al by the first partial groove 20a, the retractor member 4el knocks the first actuation member 10al out of the first partial groove 20a, as can be seen in Figures 4b and 4c, and the third rotatable unit 10 resumes co-rotating with the second rotatable unit 4.

In this example, the third rotatable unit 10 includes a retainer 24. In this example, the retainer 24 is hingedly connected to the body portion 10b of the third rotatable unit 10. Here, the retainer 24 includes a tooth 26. The tooth 26 is biased by a resilient element, here a spring 28. The second rotatable unit 4 includes a, here three, notch 30. Here the notch 30 has an angled face 30a. As can be seen in Figure 4b, when the retractor member 4e1 has knocked the first actuation member 10al out of the first partial groove 20a the tooth 26 of the retainer 24 is on the angled face 30a of the notch 30. Due to the biasing force of the resilient element 28, the tooth 26 is pushed along the angled face 30a to the bottom of the notch 30, as can be seen in Fig. 4b. As a result, the third rotatable unit 10 assumes a defined angular position relative to the second rotatable unit 4. Also, the slight angular movement from the situation shown in Figure 4b, with the actuation member 10al just freed from the groove 20, to the situation shown in Figure 4c, enables that the retractor member 4el lifts the actuation member 10al away from the groove 20, so that mechanical contact between the actuation member 10al and the fourth unit 16 can be avoided.

Having been rotated over 60 degrees, the third rotatable unit 10 has been rotated from a first position to a second position, or from a second position to a first position relative to the second rotatable unit 4. Now, the first actuation member 10al is maintained in a non-deployed position by the retractor member 4e and is maintained at a distance from the selector 18.

At approximately the same time, the other retractor member 4e3 is also rotated and releases the second actuation member 10a2 to engage the fourth unit

16. However, as can be seen in Figure 7, the second actuation member 10a2 cannot enter into the first partial groove 20a, as the shape of the second actuation member 10a2 requires the third partial groove 20c to align with the first partial groove 20a for allowing the second actuation member 10a2 to enter into the first partial groove 20a. The second actuation member 10a2 will slide along the surface of the selector 18 without being gripped.

For again actuating the third rotatable unit 10, the second partial groove 20b is moved out of alignment with the first partial groove 20a, and the third partial groove 20c is moved into alignment with the first partial groove 20a.

In this situation, the second actuation member 10a2 can enter into the first partial groove 20a. It will be appreciated that it can be possible that the second actuation member 1042 can already enter into the first partial groove 20a when the first partial groove 20a and the third partial groove 20c are not yet in complete alignment. Hence, the second actuation member 10a2 can already enter into the first partial groove 20a when the third partial groove 20e is still moving into alignment with the first partial groove 20a. When the second actuation member 10a2 has entered into the first partial groove, the first partial groove 20a supports the second actuation member 1022, allowing a force to be guided from the fourth unit 16 via the second actuation member 10a2 to the third rotatable unit 10. As a result, the third rotatable unit 10 will again be halted, and when, in use, the second rotatable unit 4 will remain rotating, the third rotatable unit 10 will be rotated relative to the second rotatable unit 4. The tooth 26 of the retainer 24 will be moved out of the notch 30 by sliding over a second angled face 30b of the notch. When the second rotatable unit 4 has rotated over approximately 60 degrees after gripping of the second actuation member 10a2 by the first partial groove 20a, the retractor member 4e, now 4e2, knocks the second actuation member 10a2 out of the first partial groove 20a and the third rotatable unit 10 resumes co-rotating with the second rotatable unit 4 again. The tooth 26 of the retainer 24 will be seated at the bottom of a notch 30 again. Having been rotated over 60 degrees, the third rotatable unit 10 has been rotated from a second position to a first position, or from a first position to a second position relative to the second rotatable unit 4. Now, the second actuation member 10a2 is maintained in a non-deployed position by the retractor member 4e again and is maintained at a distance from the selector 18 as shown in Figure 4a.

At approximately the same time, the other retractor member 4el is also rotated and again releases the first actuation member 1041 to engage the fourth unit 16. However, the first actuation member 10al cannot enter into the first partial groove 20a, as the shape of the first actuation member 10al requires the second partial groove 20b to align with the first partial groove 20a for allowing the first actuation member 10al to enter into the first partial groove 20a. The first actuation member 10al will now slide along the surface of the selector 18 without being gripped.

Thus, the selector 18 can be in a first mode for gripping the first actuation member and for not engaging the second actuation member, and in a second mode for gripping the second actuation member and not engaging the first actuation member.

It will be appreciated that in this example, forces from the third rotatable unit 10 via, the actuation members 10a are supported by the first partial groove 20a only. The second and third partial grooves 20b, 20c absorb no, or hardly any, force. The second and third partial grooves merely act as keys to select whether the first or second actuation member can enter the first partial groove 20a or not.

In the example of Figure 6, it can be seen that the fourth unit 16 includes two toothed racks 22a, 22h. The first toothed rack 22a is connected to a bush carrying the second partial groove 20b. The second toothed rack 22b is connected to a bush carrying the third partial groove 20c. The toothed racks 22a, 22b can be driven by pinions of one or two electric motors.

In the example of Figures 6 and 7, the second partial groove 20b and the third partial groove 20c are arranged to be moved relative to the first partial groove 20a in a tangential displacement. Here the second and third partial grooves 20b, 20c are arranged to be moved simultaneously in opposite directions. In this example, the second partial groove 20b is arranged for moving in the same direction the as the first actuation member 10al, i.e. along with the sliding of the first actuation member 10al along the surface of the selector 18, when the second partial groove 20b moves from the non-gripping mode to the gripping mode for the first actuation member 10al. The third partial groove 20c is arranged for moving in the same direction as the second actuation member 10a2, i.e. along with the sliding of the second actuation member 10a2 along the surface of the selector 18, when the third partial groove 20c moves from the non-gripping mode to the gripping mode for the second actuation member 10a2. Hence, forces on the selector 18 are minimized, and symmetrical for both actuation members 10a.

Figures 8a-8d show an example of gripping and ungripping the actuation members 10a in the groove 20. In Figure 8a the first actuation member 10al is arrested on the retractor member 4el. The second actuation member 10a2 is ready for being gripped by the groove 20. In Figure 8b the second rotatable unit 4 having the retractor members 4e has been rotated over 30 degrees relative to the position in Fig. 8a. In Figure 8b the second actuation member 10a2 is arrested on the retractor member 4e2. The first actuation member 10al is ready for being gripped by the groove 20. In Figure 8c the first actuation member 10al has been gripped by the groove 20. The third rotatable body 10 does not rotate. The retractor member 4e2 slips from under the second actuation member 10a2. The gripping members 4a are not engaged with the first abutment surfaces. The second body portion 10b2 of the third rotatable body 10 is not entrained in rotation over the free upshift angle as no forces act on it.

However, continued rotation of the first rotatable unit 2 relative to the third rotatable body 10 causes the gripping members 4a to engage.

Then the second body portion 10b2 of the third rotatable body 10 co-rotates with the first rotatable unit 2 in view of the engaged griping members 4a.

Then the resilient element 10e is compressed (Figure 8d) as the first body portion 10b1 of the third rotatable body 10 is still prevented from rotating by the gripped first actuation member 10al.

When the first rotatable unit 2 is driven, the gripping members 4a can automatically disengage.

When the first rotatable unit 2 is not driven, engagement of the gripping members 4a can maintain while the first actuation member 10al is lift from the groove and the first actuation member is arrested on the retractor 4e3 (forces arresting the first actuation member 10al on the retractor 4e3 must thereto be larger than the force of the compressed resilient element 10c). When the gripping members 4a are disengaged (e.g. by driving the first rotatable unit, e.g. by exerting force to the bicycle pedals) the second body portion 10b2 of the third rotatable body 10 is rotated back over the resilient upshift angle while relaxing the resilient member 10c.

Herein the gripping members 4a are retained by the retaining members 12. Thus the situation of Figure 8a is regained.

Figure 9a shows a schematic example of a torque transmission 108. The torque transmission 108 includes an input 120 and an output 122. The torque transmission 108 includes a gear transmission 124. Here the gear transmission 124 is a reduction for converting a rotational speed at the input 120 to a reduced rotational speed at the output 122. The torque transmission also includes a clutch or brake system 1, e.g. as described in view of Figures 1-7. The gear transmission 124 is selectably included in the torque transmission 108. The torque transmission is arranged for, in a first mode, transmitting the rotational speed at the input 120 unchanged to the output 122, when the clutch or brake system 1 is engaged.

The torque transmission is arranged for, in a second mode, transmitting the rotational speed at the input 120 reduced to the output 122, when the clutch or brake system Lis disengaged.

An overrunning clutch 126 is included, in this example in series with the gear transmission 124. Figure 10a shows a schematic example of a torque transmission 108. The torque transmission 108 includes an input 120 and an output 122. The torque transmission 108 includes a gear transmission 124. Here the gear transmission 124 is a arranged for converting a rotational speed at the input 120 to an increased rotational speed at the output 122. The torque transmission also includes a clutch or brake system 1, e.g. as described in view of Figures 1-7. The gear transmission 124 is selectably included in the torque transmission 108. The torque transmission is arranged for, in a first mode, transmitting the rotational speed at the input 120 unchanged to the output 122, when the clutch or brake system 1 is disengaged. The torque transmission is arranged for, in a second mode, transmitting the rotational speed at the input 120 increased to the output 122, when the clutch or brake system 1 is engaged. An overrunning clutch 126 is included, in this example in parallel with the gear transmission 124.

Figure 9b shows a schematic example of a torque transmission 108. The torque transmission 108 includes an input 120 and an output 122. The torque transmission 108 includes a gear transmission 124. Here the gear transmission 124 is a planetary gear system 124A for converting a rotational speed at the input 120 to a reduced rotational speed at the output 122. In this example, the input 120 is connected to the annulus 124Aa of the planetary gear system 124A. Here, the output 122 is connected to the carrier 124Ac of the planetary gear system 124A. The torque transmission also includes a clutch or brake system 1, e.g. as described in view of Figures 1-7, here included selectively connecting the annulus and the carrier. The sun wheel 124As of the planetary gear system 124A is connected to a non-rotary part via the overrunning clutch 126. The torque transmission is arranged for, in a first mode, transmitting the rotational speed at the input 120 unchanged to the output 122, when the clutch or brake system 1 is engaged. The torque transmission is arranged for, in a second mode, transmitting the rotational speed at the input 120 reduced to the output 122, when the clutch or brake system 1 is disengaged. Decoupling of the overrunning clutch 126 may be required for allowing the output 122 in reverse direction. An input overrunning clutch 128 may be required for freewheeling, e.g. while driving without pedaling.

Fig. 9c shows a schematic cross section of a torque transmission 108 according to Fig. 9b in an axle assembly 100, such as a bicycle rear wheel assembly.

Figure 10b shows a schematic example of a torque transmission 108. The torque transmission 108 includes an input 120 and an output 122. The torque transmission 108 includes a gear transmission 124. Here the gear transmission 124 is a planetary gear system 124B for converting a rotational speed at the input 120 to an increased rotational speed at the output 122. In this example, the input 120 is connected to the carrier 124Bc of the planetary gear system 124B. Here, the output 122 is connected to the annulus 124Ba of the planetary gear system 124B. The torque transmission also includes a clutch or brake system 1, e.g. as described in view of Figures 1-7, here included selectively connecting the sun wheel 124Bs of the planetary gear system 124B to a non-rotary part. The carrier is connected to the annulus via an overrunning clutch 126. The torque transmission is arranged for, in a first mode, transmitting the rotational speed at the input 120 unchanged to the output 122, when the clutch or brake system 1 is disengaged. The torque transmission is arranged for, in a second mode, transmitting the rotational speed at the input 120 reduced to the output 122, when the clutch or brake system 1 is engaged. Decoupling of the overrunning clutch 126 may be required for allowing the output 122 in reverse direction. An input overrunning clutch 128 may be required for freewheeling, e.g. while driving without pedaling.

Fig. 10c shows a schematic cross section of a torque transmission 108 according to Fig. 10b in an axle assembly 100, such as a bicycle rear wheel assembly.

Figure 11 shows an example of an axle assembly 100. In this example, the axle assembly is a rear bicycle assembly. The axle assembly 100 here includes a hollow axle 101. In this example, the hollow axle 101 is arranged for non-rotatably being fixed to a frame, e.g. a bicycle frame. In this example the axle assembly is an axle assembly for a bicycle. The axle assembly 100 includes a hub 102. Here the hub 102 is provided with apertures 104, e.g. for connection of spokes of a wheel, The axle assembly 102 further includes a driver 106. The driver 106 in this example is arranged for receiving a cassette of gear wheels (not shown).

The axle assembly 100 in this example includes a torque transmission 108, Here the torque transmission includes a clutch or brake system 1, e.g. as described in view of Figures 1-7, and a gear means, here a planetary gear 110, The planetary gear 110 includes a sun gear 112, a planet carrier 114 with planet gears 116 and a ring gear 118. The clutch or brake system 1 is arranged in the torque transmission 108 so as to selectively couple two of the sun gear, the planet carrier and the ring gear. In this example, In this example, the clutch or brake system 1 is arranged in the torque transmission 108 so as to selectively couple the planet carrier 114 and the ring gear 118. The planet carrier 114 is also fixedly coupled to the hub 102. Therefore, depending on whether the first rotatable unit 2 and second rotatable unit 4 are rotationally coupled, or rotationally disengaged, driving the driver 106 causes the hub 102 to rotate according to a first or second gear ratio relative to the driver 106. An overrunning clutch may thereto be positioned between the sun gear 112 and the axle 101.In the examples of Figures 1-7 and 8, the first rotatable unit 2, the second rotatable unit 4, the third rotatable unit 10, and the fourth unit 16 are coaxial. Here, the fourth unit 16 is positioned at least partially within the third rotatable unit 10. Here the third rotatable unit 10 is at least partially positioned within the second rotatable unit 4. Here the second rotatable unit 4 is at least partially positioned within the first rotatable unit 2.

Figs. 12, 13a-b and 14a-b show further examples of a mechanism for moving the third rotatable unit 10 from a first position (e.g. the first position or a first position of the plurality of first positions) to a second position (e.g. the second position or a second position of the plurality of second positions) or from a second position (e.g. the second position or a second position of the plurality of second positions) to a first position (e.g. the first position or a first position of the plurality of first positions) relative to the second rotatable unit.

In the examples of Figs. 12, 13a-b and 14a-b, the retainer 24 is different than in the example of figures 4A-4C and 5. Here, the retainer 24 is formed as a an axially oriented retainer pin, shown in Figs. 15a-c. In this example, four retainer pins are provided (divided over 360 degrees by 60-120-60-120 degrees ). The retainer pin 24 is slidably held in a bore 24a in the first body portion 10b1. The second rotatable unit 4 includes a, here four, notch 30. The retainer pin 24 is biased towards the second rotatable unit 4 by a resilient element 28, here a compression spring. A tip of the retainer pin 24 which is directed towards the second rotatable unit 4 here is rounded. The rounded tip can match a shape of the notch 30. The notch 30 further has an angled face 30a. Within a certain angle of relative rotation from a predefined position, the third rotatable unit will reset its position due to the spring forces and the shape of the groove and top of the retainer pin.

When the retractor member 4el has knocked the first actuation member 10al out of the first partial groove 20a, the tip of the retainer pin 24 is on the angled face 30a of the notch 30, as can be seen in Fig. 15b.

Due to the biasing force of the resilient element 28, the tip is pushed along the angled face 30a to the bottom of the notch 30, as can be seen in Fig. 15c.

As a result, the third rotatable unit 10 assumes a defined angular position relative to the second rotatable unit 4. Also, the slight angular movement from the situation shown in Fig. 15b, with the actuation member 10al just freed from the groove 20, to the situation shown in Fig. 15c, enables that the retractor member 4el lifts the actuation member 10al away from the groove 20, so that mechanical contact between the actuation member 10al and the fourth unit 16 can be avoided.

In the example of Fig. 12, the clutch or brake system 1 is arranged such that when during use the gripping member 4a contacts the retaining member 12 at a border between a ramp, here a sloping surface 12a, and an adjacent plateau surface 12b of the retaining member 12, an outer tip of one actuation member 10a substantially simultaneously contacts a retractor member 4e at a trailing edge thereof, just prior to being released from said retractor member 4e.

In the exemplary situation of Fig. 12 the first actuation member 1041 can be seen as accordingly contacting a retractor member 4e at a trailing edge thereof, while the second actuation member 10a2 can be seen as positioned in one of the grooves 20 just prior to being lifted therefrom by an adjacent retractor member 4e.

The first actuation member 10al thus being released from the retractor member 4e when the gripping member 4a reaches the plateau surface 12b enables that while the gripping member 4a is in contact with the plateau surface 12b, at least one of the actuation members 10 is available for engagement with (or is engaged with) a groove 20, so that the gripping member 4a can thereby be disengaged from the first rotating member 2 if and when desired while the gripping member 4a is engaged with the first rotating member 2. In the same exemplary configuration of Fig. 12, the first actuation member 10al thus not being released from the retractor member 4e while the gripping member 4a is in contact with the slopmg surface 124 helps to prevent the system 1 from locking up by preventing the first actuation member 10al from engaging a groove 20 while the gripping member 4a is in contact with, e.g. traveling along, the sloping surface 12a.

In the example of Figs. 13a-b, the clutch or brake system 1 is configured such that when during use the gripping member 4a contacts the retaining member 12 at the sloping surface 12a and nearly contacts (or contacts) the first rotating member 2 at an inner plateau surface 6a adjacent the abutment surface 6, one of the actuation members 10a is substantially simultaneously being released from a groove 20 by a retractor member 4e. Fig. 13a shows the second actuation member 10a2 thus being positioned just outside a groove 20 as a result of contact with an adjacent retractor member 4e. To this end, compared to the example of Fig. 12, the retractor members 4e each extend further along the circumferential direction, here by about 13 degrees compared to Fig. 12.

Such a configuration can help to prevent the system 1 from locking up by preventing that the gripping member 4a is forced (e.g. clamped) against the inner plateau surface 6a. From the situation shown in Fig. 13a onwards, the retainer 24, here retainer pins 24 held in respective bores 24a, can subsequently cause the retaining member 12 to further align with the gripping member 4a by engaging the notches 30, such that the second rotating unit 4 is thereby coupled to the first rotating unit 2. To this end, the notches 30, in particular the respective angled faces 30a, are in the situation of Fig. 13a positioned to be engageable by the retainer pins 24 for rotating the second rotating member 4 to align the notches 30 with the pins 24 at the bores 24a. Once thus aligned, the gripping member 4a is positioned on the plateau surface 12b of the retaining member 12, as shown in Fig. 13b, so that the second and first rotating units 4, 2 are subsequently coupled.

In the configuration of Fig. 13a, the first and second body portions 10b1, 10b2 can be fixed with respect to each other, e.g. as part of a single integral body, wherein a resilient element between the body portions 10b1, 10b2 (such as resilient element 10c in Figs. 4a-c and 5) can be omitted.

In the example of Fig. 14a-h, as shown in Fig. 14a, the clutch or brake system 1 is configured such that when during use the gripping member 4a contacts the retaining member 12 at the ramp, here sloping surface, 12a and nearly contacts (or contacts) the first rotating member 2 at an inner plateau surface 6a adjacent the abutment surface 6, one of the actuation members 10a, here the first actuation member 10al, is substantially simultaneously pushed against a trailing side of a retractor member 4e, in particular pushed by a tangential spring force between the first and second body portions 10b1, 10b2 caused by the resilient element 10e arranged therebetween (see Figs. 4a-c and 5 for the resilient element 10c). To effectively enable such pushing, the system 1 is preferably configured such that a spring force associated with the retainer 24 (e.g. a total spring force of the retainer springs 28) is small compared to a spring force associated with the resilient element 10c, at least when the gripping member 4a thus contacts the retaining member 12 at the sloping surface 124 while being immediately adjacent the first rotating member 2 at an inner plateau surface 6a adjacent the abutment surface 6.

Such a configuration can help to prevent the system 1 from locking up by preventing that the first actuation member 10al can engage with a groove 20 while the gripping member 4a nearly contacts or contacts the inner plateau surface 6a. Once the gripping member 4a has moved away from said surface 6a, the resilient element 10c and/or the retainer 24 can cause the retaining member 12 to subsequently be moved in alignment with the gripping member 4a for completing the coupling between the second and first rotating units 4, 2. During this time, as shown in Fig. 14b, the second actuation member 10a2 is (further) retracted from the third unit 16 by one of the retractor members 4e.

While Figs. 14a-b show both actuation members 10a as being rotatably held in the first body portion 10b1, alternatively one of the actuation members 10a, in particular the second actuation member 10a2 can be held in the second body portion 10b2 (which as mentioned includes the retaining members 12), so that advantageously said actuation members 10a can move with respect to each other under influence of the resilient element 10c arranged between the body portions 10b1, 10b2, in particular move with respect to each other along the circumferential direction of the system 1. In this way, further prevention of locking up of the system 1 can be provided.

The clutch or brake system 1 can e.g. be used for selectively operating a planetary gear according to a first mode when the second rotatable unit is engaged with the first rotatable unit, and according to a second mode when the second rotatable unit is disengaged from the first rotatable unit. Hence, the clutch or brake system 1 can be used in a torque transmission for operating the torque transmission at a first transmission ratio in the first mode, and at a second, different transmission ratio in the second mode. The clutch or brake system can e.g. be used in a rear hub of a bicycle. The clutch or brake system can then be used e.g. for emulating the functioning of a front derailleur, so as to be able to omit the front derailleur from the bicycle. The invention also relates to a bicycle including such clutch or brake system.

Herein, the invention is described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein, without departing from the essence of the invention. For the purpose of clarity and a concise description features are described herein as part of the same or separate examples or embodiments, however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also envisaged.

In the examples, the first rotatable unit includes nine first abutment surfaces. It will be appreciated that other numbers of first abutment surfaces, such as one, two, three, four, six or any other suitable number are also possible. In the examples, the second rotatable unit includes three second abutment surfaces. It will be appreciated that other numbers of second abutment surfaces, such as one, two, four, six or any other suitable number are also possible. In the examples, the third rotatable unit includes three retaining members. It will be appreciated that other numbers of retaining members, such as one, two, four, six or any other suitable number are also possible. In the examples, the third rotatable unit includes two actuation members. It will be appreciated that other numbers of actuation members, such as one, three, four, six or any other suitable number are also possible.

In the examples, the gripping members are separate items hingedly connected to the body portion of the second rotatable unit. It will be appreciated that it is also possible that the gripping members are integral with the body portion of the second rotatable unit.

In the examples, the third rotatable unit includes an first body portion and a second body portion. It will be appreciated that the first and second body portions may also be an integral portion.

In the examples, the actuation members are separate items hingedly connected to the body portion of the third rotatable unit. It will de appreciated that it is also possible that the actuation members are integral with the body portion of the third rotatable unit.

In the examples, the gripping members are arranged for pivoting in a radial direction. It will be appreeiated that it is also possible that the gripping members are arranged for pivoting in an axial direction. Then e.g. the second rotatable unit and the first rotatable unit can be positioned, at least partially, axially next to each other. Also, then the third rotatable unit and the second rotatable unit can be positions, at least partially, axially next to each other.

In the examples, the actuation members are arranged for pivoting in a radial direction. It will be appreciated that it is also possible that the actuation members are arranged for pivoting in an axial direction. Then e.g. the third rotatable unit and the fourth unit can be positioned, at least partially, axially next to each other.

Herein, the invention is described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications, variations, alternatives and changes may be made therein, without departing from the essence of the invention. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also envisaged and understood to fall within the framework of the invention as outlined by the claims. The specifications, figures and examples are, accordingly, to be regarded in an illustrative sense rather than in a restrictive sense. The invention is intended to embrace all alternatives, modifications and variations which fall within the spirit and scope of the appended claims. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising’ does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words ‘a’ and ‘an’ shall not be construed as limited to ‘only one’, but instead are used to mean ‘at least one’, and do not exclude a plurality.

The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to an advantage.

Claims

Conclusions

A clutch or braking system for a torque transmission comprising an input adapted to be coupled to a drive source, and an output adapted to be coupled to a load, the coupling system comprising: a first rotatable unit coupleable to the input or output comprising at least a first stop surface; a second rotatable unit coupleable to the output or input, respectively, comprising at least a second stop surface adapted to selectively engage the first stop surface, the first and second stop surfaces being adapted to each other such that they can be disengaged under load, e.g. ... in two directions; a third rotatable unit comprising at least one retaining member, the third unit being arranged to be selectively located in a first rotational position or a second rotational position relative to the second rotatable unit, the at least one retaining member in the first rotational position blocking a second stop surface from rotationally coupling the second unit to the first unit, and in the second rotational position clears the at least one second stop surface for uncoupling the second unit from the first unit; wherein the third rotatable unit comprises at least two operating elements adapted to move the third rotatable unit from a first position to a second position or from a second position to a first position relative to the second rotatable unit;

a fourth unit comprising a selector, the selector being configured to be selectively in an engaging mode or non-engaging mode, the selector being configured in the engaging mode for engaging at least one of the at least two control elements for rotating the third rotatable unit from the first position to the second position or from the second position to the first position relative to the second rotatable unit; wherein the selector in the non-engaging mode 1s arranged to not engage the at least two operating elements; the second rotatable unit comprising a return means adapted to move the at least two operating elements out of engagement with the selector; wherein the at least one second stop surface and at least one of the at least two actuating members are angularly positioned such that when the at least one second abutment surface just engages the first abutment surface, the at least one of the at least two actuating members still engages the return member .

The clutch or braking system of claim 1, wherein the at least one second stop surface is an engagement member adapted to move radially into and out of engagement with the at least one first stop surface.

The clutch or braking system of claim 2, wherein the at least one second stop surface and at least one of the at least two actuating members are angularly positioned such that when the at least one engagement member engages a slope of the at least one retaining member and the at least one second stop surface of the engaging element engages or is immediately adjacent to a radially inner surface of the first unit, the other of the at least two actuating elements is moved just out of engagement with the selector by the return member.

The clutch or braking system of claim 3, wherein the at least two operating elements are pivotally connected to the third unit.

The clutch or braking system of claim 4, wherein the at least two actuating elements are biased toward the fourth unit by spring elements.

The clutch or braking system of any of claims 1-5, wherein the third unit has predetermined angular indexing positions relative to the second unit, such as six predetermined indexing positions.

The clutch or braking system of claims 2 and 6, wherein the angular indexing positions are such that in at least one of the indexing positions the engagement member is positioned on the top of the retaining member.

The clutch or braking system of claims 2 and 6, wherein the angular indexing positions are such that in at least one of the indexing positions the engagement member is positioned on a front ramp of the retaining member.

The clutch or braking system of any one of claims 1-8, wherein the third rotatable unit comprises a first body and a second body, the first body comprising the at least one retaining member, and the second body comprising at least one of the includes at least two operating elements.

The clutch or braking system of claim 9, wherein the first body is rotationally resiliently coupled to the second body.

The clutch or braking system according to claim 9 or 10, wherein the first body comprises the at least one retaining member, and the second body comprises two operating elements.

The clutch or braking system of any of claims 1-11, wherein the third rotatable unit comprises at least one retainer, and the second rotatable unit comprises at least one notch, or wherein the second rotatable unit comprises at least one retainer, and the third rotatable unit comprises at least one notch for indexing the second rotatable unit relative to the third rotatable unit by resiliently engaging at least one of the at least one retainers in at least one of the at least one notches.

The clutch or braking system of claim 12, wherein the retainer is pivotally connected to the third rotatable unit, such as for pivotal movement about a pivot axis parallel to the rotational axis of the third rotatable unit.

The clutch or braking system of claim 12, wherein the retainer is formed as a pin slidable along an axis parallel to the axis of rotation of the third rotatable unit.

The clutch or braking system of claims 9 and 14, wherein a first force biasing the slidable pin toward the notch may be less than a second force biasing the first body relative to the second body.

The clutch or braking system of any one of claims 8 to 15, wherein the at least one second stop surface and at least one of the at least two actuating members are angularly positioned such that when the at least one engagement member is inclined at the at least one retaining member engages and the at least one second abutment surface of the engaging member engages or is immediately adjacent to a radially inner surface of the first unit, one of the at least two actuating members is biased against a rear side of the return member, in particular pushed by a tangential spring force exerted by a spring element arranged between the first and second bodies of the third unit.

The clutch or braking system of any one of claims 8-16, wherein the first body comprises the at least one retaining member and one of the at least two operating elements, and the second body comprises another of the at least two operating elements.

The clutch or braking system of any one of claims 1 to 17, wherein the third rotatable unit is arranged to co-rotate with the second rotatable unit, and the system is arranged to cause the third rotatable unit to temporarily change its rotational speed at the same time as relative to the second rotatable unit for rotating from the first position to the second position, or from the second position to the first position.

The clutch or braking system of any one of claims 1-18, wherein the third rotatable unit is rotatable with respect to the second rotatable unit, and a rotation angle of the third rotatable unit with respect to the second rotatable unit is unlimited.

The clutch or braking system of claim 19, wherein the third rotatable unit is arranged to be rotated from the first position to the second position, and from the second position to the first position in one and the same rotational direction.

The clutch or braking system of claim 19 or 20, wherein the third rotatable unit is arranged to be selectively located in one of a plurality of first or second positions relative to the second rotatable unit.

The clutch or braking system of any one of claims 1 to 21, wherein the second and third rotatable units are free from biasing force with respect to each other.

The clutch or braking system of any one of claims 1 to 22, wherein the engagement or disengagement of the second stop surface with the at least one first stop surface is independent of input torque and/or rotational speed.

The clutch or braking system of any one of claims 1 to 23, wherein the selector comprises a groove comprising a first partial groove and a second partial groove, wherein in engaged mode the partial grooves permit coupling of the at least one actuating element, and in non-engaging mode, the partial grooves allow resisting engagement of the at least one actuating element.

The clutch or braking system of any one of claims 1-24, comprising two actuating elements, optionally arranged such that when the first actuating element is biased into contact with the selector, the second actuating element is spaced from the selector and vice versa .

The clutch or braking system of claim 25, wherein the selector is arranged to be in a first mode or in a second mode, the selector being in the first mode engaged mode for the first operating element and in non- engaging mode for the second operating element, and wherein the selector is in the second mode in non-engaging mode for the first operating element and in engaging mode for the second operating element.

The clutch or braking system of claim 26, wherein the selector comprises a groove comprising a first partial groove, a second partial groove and a third partial groove, wherein in the first mode the first and second partial grooves engage the first operating element, and in the second mode, the second and third grooves permit engagement of the second operating element.

The clutch or braking system of claim 27, wherein the first partial groove, the second partial groove and the third partial groove extend substantially axially on a cylindrical surface of the fourth unit.

The clutch or braking system of claim 27 or 28, wherein the second partial groove and the third partial groove are adapted to be moved.

The clutch or braking system of claim 29, wherein the second partial groove and the third partial groove are arranged to be moved in opposite directions.

The clutch or braking system of claim 30, wherein the second partial groove is adapted to move in the same direction as the first operating element when the second partial groove moves from the non-engaging mode to the engaging mode for the first operating element, and the third partial groove 1s arranged to move in the same direction as the second operating element when the third partial groove moves from the non-engaging mode to the engaging mode for the second operating element.

The clutch or braking system of any one of claims 1 to 31, wherein the at least one actuating element is adapted to move radially into and out of engagement with the fourth unit.

The clutch or braking system of any one of claims 1 to 32, wherein the first and/or second stop surface is biased to disengage.

The clutch or braking system of any one of claims 1-33 comprising a plurality of first and/or second stop surfaces.

The clutch or braking system of any one of claims 1-34, comprising a plurality of retaining members.

The clutch or braking system of any one of claims 1 to 35, wherein the first, second, third and/or fourth units are coaxial.

The clutch or braking system of any one of claims 1 to 36, wherein the fourth unit is positioned at least partially within the third rotatable unit, and/or the third rotatable unit is positioned at least partially within the second rotatable unit, and /or the second rotatable unit is positioned at least partially within the first rotatable unit.

A torque transmission comprising a clutch or braking system, for example according to any one of claims 1-37, and a planetary gear system, wherein the clutch or braking system is arranged in the torque transmission so as to selectively two of a sun gear, a planet carrier and a ring gear of to couple the planetary gear system.

The torque transmission of claim 38, wherein the ring gear is rotationally fixed to the first rotatable unit and the planet carrier is rotationally fixed to the second rotatable unit, or wherein the ring gear is rotationally fixed to the second rotatable unit and the planet carrier is rotationally fixed to the first rotatable unit.

The torque transmission according to claim 38 or 39, wherein the sun gear is connected to the fourth unit through a unidirectional bearing.

The torque transmission of claim 40, wherein the unidirectional bearing is configured to allow rotation of the sun gear in the forward direction relative to the fourth unit.

The torque transmission of claim 40 or 41, wherein the unidirectional bearing is arranged to allow rotation of the sun gear relative to the fourth unit with minimal friction and/or noise.

The torque transmission of claim 40, 41 or 42, wherein the unidirectional bearing is adapted to block rotation of the sun gear in the rearward direction relative to the fourth unit.

The torque transmission according to any one of claims 40-43, wherein the unidirectional bearing is adapted to allow a torque of up to 118 Nm, and/or to prevent slip.

The torque transmission of any one of claims 40-44, wherein the unidirectional bearing is a radial unidirectional bearing with rollers or ratchet teeth.

The torque transmission of any one of claims 40-45, wherein the unidirectional bearing is an axial unidirectional bearing with rollers or ratchet teeth.

A wheel axle assembly, such as a bicycle wheel axle assembly, comprising a torque transmission according to any one of claims 38-46.

The wheel axle assembly of claim 47, wherein an axle of the wheel axle assembly is rotationally fixed to the fourth unit.

The wheel axle assembly of claim 47 or 48, wherein a driver body is connected to the first rotatable unit or the second rotatable unit.

The wheel axle assembly of any one of claims 47-49 adapted to receive a cassette having a plurality of sprockets.

A bicycle comprising a clutch or braking system according to any one of claims 1-37, a torque transmission according to any one of claims 38-46, or a wheel axle assembly according to any one of claims 47-50.

A method of operating a clutch or braking system for a torque transmission comprising an input adapted to be coupled to a drive source, and an output adapted to be coupled to a load, the method comprising: - providing a clutch - or braking system according to any one of claims 1-37; and - rotating the third rotatable unit relative to the second rotatable unit from the first rotational position to the second rotational position for disengaging the clutch or braking system, and rotating the third rotatable unit relative to the second rotatable unit of the second rotational position to the first rotational position for coupling the clutch or braking system.

The method of claim 52, comprising co-rotating the third rotatable unit with the second rotatable unit, and temporarily changing rotational speed of the third rotatable unit relative to the second rotatable unit to rotate the third rotatable unit. unit from the first position to the second position, or from the second position to the first position, relative to the second rotatable unit.

The method of claim 53, comprising automatically resuming co-rotation of the third rotatable unit with the second rotatable unit after the third rotatable unit has been rotated from the first rotational position to the second rotational position or vice versa.

A method of operating a clutch or braking system for a torque transmission comprising an input adapted to be coupled to a drive source, and an output adapted to be coupled to a load, the method comprising: - providing a clutch - or braking system according to any one of claims 1-37; and - temporarily changing rotational speed of the third rotatable unit relative to the second rotatable unit for rotating the third rotatable unit from the first rotational position to the second rotational position, or from the second rotational position to the first rotational position, relative to the second rotatable unit.

The method according to any one of claims 52-55, comprising rotating the third rotatable unit from the first rotational position to the second rotational position and from the second rotational position to the first rotational position in one and the same rotational direction.

The method according to any one of claims 52-56, comprising: - with the selector in the engaging mode, engaging at least one of the at least two operating elements to rotate the third rotatable unit from the first rotational position to the second rotational position or from the second rotational position to the first rotational position relative to the second rotatable unit; and - with the selector in the non-engaging mode, not engaging the at least one of the at least two operating elements.

A method of operating a clutch or braking system for a torque transmission comprising an input adapted to be coupled to a drive source, and an output adapted to be coupled to a load, the method comprising: - providing a clutch - or braking system according to any one of claims 1-37; and - with the selector in the engaging mode, engaging at least one of the at least two operating elements to rotate the third rotatable unit from the first rotational position to the second rotational position or from the second rotational position to the first rotational position relative to the second rotatable unit; and - with the selector in the non-engaging mode, not engaging the at least one of the at least two operating elements.

The method according to claim 58, comprising: - in the first rotational position blocking the at least one second stop surface for rotationally coupling the second rotatable unit to the first rotatable unit, and - in the second rotational position releasing the at least one second stop surface for disengaging the second rotatable unit from the first rotatable unit.

The method of any one of claims 57-59, comprising moving the at least one of the at least two operating elements out of engagement with the selector after the third rotatable unit 1s rotated from the first rotational position to the second rotational position, or from the second rotational position to the first rotational position.

The method of any one of claims 57-60, wherein the selector comprises a groove comprising a first partial groove and a second partial groove; the method comprising:

- in the engaging mode, allowing the partial grooves to engage the at least one actuating element, and - in the non-engaging mode, allowing the partial grooves to counteract engagement of the at least one actuating element.

The method of any of claims 57-61, wherein the third rotatable unit comprises two actuators, optionally arranged such that when the first actuator is biased into contact with the selector, the second actuator is spaced from the selector and vice versa, the method comprising: - selectively setting the selector in a first mode or in a second mode, wherein in the first mode the selector is in the engaging mode for the first operating element and in non-engaging mode for the second operating element, and wherein in the second mode the selector is in non-engaging mode for the first operating element and in engaging mode for the second operating element.

The method of claim 62, wherein the selector comprises a groove comprising a first partial groove, a second partial groove and a third partial groove, wherein in the first mode the first and second partial grooves allow engagement of the first actuating element, and in the second mode, the second and third partial grooves allow engagement of the second actuating element.

The method of claim 63, comprising moving the second and third partial grooves in opposite directions.

The method according to claim 63 or 64, comprising - moving the second partial groove in the same direction as the first operating element when the second partial groove moves from the non-engaging mode to the engaging mode for the first operating element, and - moving the third partial groove in the same direction as the second operating element when the third partial groove moves from the non-engaging mode to the engaging mode for the second operating element.