GB2136065A

GB2136065A - Gear-change device for a multi- ratio cycle hub

Info

Publication number: GB2136065A
Application number: GB08402789A
Authority: GB
Inventors: Dieter Klauke; Gerhard Wolf
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1983-02-02
Filing date: 1984-02-02
Publication date: 1984-09-12
Also published as: DE8302727U1; GB2136065B; JPS59143789A; GB8402789D0

Abstract

The gear-change device (1) comprises a securing part (5) screwed on to the threaded end of a hub spindle (3) of the multi-ratio hub (1) and a distance-compensating part (17) guided displaceably in relation to the securing part, which part (17) is arranged in a gear-change force path of the multi- ratio hub (1), leading from a manually actuatable actuating cable by way of a deflection element (27) to a gear- change element (13), in such manner that it can allow delay between movement of the actuating cable and movement of the gear-change element (13). The distance-compensating part (17) is supported on a spring (57) acting against the distance-compensating movement, the force of which spring is greater than an oppositely directed force exerted on the gear-change element (13). A detent device (47, 53) defines the positions of the actuating cable in relation to the distance- compensating part (17). The distance- compensating part (17) and spring (57) allow pre-selection of gears when the gear elements are locked by drive torque. <IMAGE>

Description

SPECIFICATION Gear-change device for a multi-ratio cycle hub The invention relates to a gear-change device for a multi-ratio cycle hub in the hub spindle of which, provided at the end with an external threading, a gear-change element is axially movably guided.

Such a gear-change device is known from Fed.

German Pub. Sp. 27 23 869. It comprises a holder secured on the threaded end of the hub spindle and an actuating device actuatable manually by means of a gear-change lever or the like, which is coupled with the gear-change element of the multi-ratio hub through an actuating cable which can be subjected to either tension or compression stress and is guided movably approximately radially of the hub spindle in the region of the holder. On the holder there is movably guided a deflector element in the form of a double-armed bell-crank lever or a draw chain which connects the actuating cable, movable radially in the region of the holder, with the axially movable gear change element. A detent device held on the holder and acting on the deflector element positions the actuating cable in the positions corresponding to the gear-change positions of the gear-change element.Since the actuating cable is detained in the region of the multi-ratio hub, the gear-change positions of the gear-change element can be indexed irrespective of stretches and the like of the actuating cable occurring in operation.

In the known gear-change device the holder is clamped by means of a screw to the threaded end of the hub spindle. For this purpose either the hub spindle must be provided with additional detent and clamping faces, or the danger exists that the threading may be damaged in the fitting of the holder. In addition to the holder a separate collar nut is necessary for fastening the multi-ratio hub to the cycle frame.

It is the problem of the invention to improve the above-explained gear-change device so that it can be fitted more easily to the hub spindle of the multi-ratio cycle hub and so that furthermore it comprises a shift distance reservoir permitting manual movement of the actuating device even if the multi-ratio hub is subject to drive loading and thus for the moment cannot follow the shift movement.

According to the invention on a securing part of the holder which can be secured on the hub spindle there is movably guided a distance compensating part which is arranged in the gearchange force path leading from the actuating cable by way of the deflector element to the gearchange element, in such manner that it can compensate the shift distance of the actuating cable in relation to the gear-change element at least for one gear. In this way the actuating cable can be displaced manually even if the gear-change element cannot carry out any gear-change movement by reason of the drive loading of the multi-ratio hub.The distance-compensating part is supported on a spring acting against the distance compensation movement, the spring force of which spring is greater than an oppositely directed force exerted by the gear-change element upon the distance-compensating part in the shift movement of the gear-change element. The spring serves as storage spring which is stressed by manual displacement of the actuating cable. It is stronger than the gear-change spring provided in the multi-ratio hub. When the locking of the gear change element is eliminated the spring presses the distance-compensating part into its normal position, the gear-change element being moved against the force of the gear-change spring of the gear hub into its gear-change position corresponding to the pre-setting of the actuating cable.The detent device here defines the positions ofthe actuating cable in relation to the distance-compensating part so that the pre-setting of the actuating cable is maintained until the locking of the gear-change element is eliminated and the storage spring of the distance-compensating part can move the gear-change element.

The force transmission path from the actuating cable to the gear-change element preferably stresses the storage spring only in the direction opposite to the direction of the force of the gearchange spring. Inthe opposite direction of the force-transmission path an idle motion device ensures that the position of the actuating cable can be shifted without stressing the gear-change spring even if the gear-change element is locked.

For this direction of actuation the gear-change spring takes over the storage function. The storage spring provided for the first-mentioned direction of actuation can be provided between the distancecompensating part and the holder or directly in the force-transmission path.

It should be pointed out that by the feature of the actuating cable there is to be understood any substantially elongated force-transmission connection, including for example rod linkages and the like. The deflector elements, according to the design of the multi-ratio hub, can convert a pulling movement of the actuating cable into a pulling movement of the gear-change element or a pulling movement of the actuating cable into a thrust movement of the gear-change element. For this purpose connecting chains or single- or doublearmed levers articulated to the holder are suitable.

In a preferred form of embodiment the securing part is formed as a threaded sleeve which can be screwed on to the threaded end of the hub spindle, on which sleeve the distancecompensating part is guided both axially displaceably and coaxially rotatably. The threaded sleeve is used at the same time as spindlesecuring nut for the multi-ratio hub and the distance-compensating part at the same time compensates for different spindle lengths. The distance-compensating part expediently engages in the threaded sleeve, namely so that it strikes upon the end face of the hub spindle. The end face of the hub spindle in this manner forms a reference face in relation to which the detent device, acting between the actuating part and the distance-compensating part, can be adjusted.The spring used as storage spring here acts between the threaded sleeve and the distancecompensating part and initially stresses the distance-compensating part against the end face of the hub spindle.

An example of embodiment of the invention is to be explained in greater detail hereinafter by reference to drawings, wherein:- FIGURE 1 shows a diagrammatic sectional view of a gear-change device for securing on the hub spindle of a multi-ratio cycle hub, seen along a line I-I in Figure 2, and FIGURE 2 shows a plan view of the gear change device seen in the axial direction from the multi-ratio hub.

The Figures show a multi-ratio cycle hub 1, indicated in dot-and-dash lines, the hub spindle 3 of which is provided with an external threading at the end and is screwed by means of a threaded sleeve 5 of a gear-change device 7, explained in greater detail hereinafter, with interposition of a washer 9 to a rear fork of the cycle, indicated at 11, without additional collar nut or the like. The hub spindle 3 of the multi-ratio hub 1 is of hollow formation and axially displaceably guides a gearchange rod 13 by the axial displacement of which the gear position of the multi-ratio hub 1 is determined. A gear-change spring (not illustrated further) of the multi-ratio hub 1 initially stresses the gear-change rod 13 axially in the direction towards the gear-change device 7.The gearchange device 7 deflects the gear-change movement of a Bowden cable 15, which can be subjected to either tension or compression stress and extends in the region of the gear-change device 7 transversely of the axial direction of the hub spindle 3, into the axial movement of the gear-change rod 13. The Bowden cable 15 can be actuated manually by means of a hand lever (not illustrated further) and controls the gear-change position of the multi-ratio hub 1.

A deflection housing 1 7 is guided rotatably coaxially with the hub spindle 3 on the threaded sleeve 5. The deflection housing 17 with a substantially cylindrical housing part 1 9 axially displaceably encloses the cylindrical part remote from the hub of the threaded sleeve 5 which moreover is provided with spanner faces 21. On the side of the cylindrical housing part axially remote from the spanner faces 21 and the multiratio hub 1 a housing socket 23 of the deflection.

housing 17 adjoins in axial extension of the threaded sleeve 5, into which socket an arm 25 of a two-armed bell-crank lever 27 engages. The bell-crank lever 27 is mounted pivotably on the deflection housing 17 by means of a spindle 29 extending transversely of the hub spindle 3, and has a nose 31 extending in front of the front of the free end of the gear-change rod 13 extending into the housing socket 23. A second arm of the bellcrank lever 27, which protrudes at an angle to the arm 25 from the spindle 29 towards the multiratio hub 1 is firmly connected with the hub end of an actuating cable 37 guided displaceably in a sheath 35 of the Bowden cable 15.The cable jacket or sheath 35 of the Bowden cable 15 is supported on a housing extension piece 39 which extends transversely of the cylindrical housing part 19 and guides the Bowden cable 15 transversely of the hub spindle towards the arm 33 of the bellcrank lever 27. The sheath 35 of the Bowden cable 1 5 is fixed, as may best be seen from Figure 2, in a recess 41. The free end of the actuating cable 37 is held in a screw clamp 43 fitted on the free end of the arm 33. From the screw clamp 43 a guide plate 45 extends towards the sheath 35 and guides the part of the actuating cable 37 extending unguided between the sheath end and the screw clamp 43.

The edge of the arm 25 facing the housing part 39 has substantially the form of an arc of a circle into which detent recesses 47 for each of the gear positions of the multi-ratio hub 1 are formed radially of the axis 29 from the edge. A detent ball 51 is seated radially displaceably in an opening 49, extending radially of the axis 29, of the housing extension piece 39 and is pressed by a leaf spring 53 into the detent openings 47. The leaf spring 53 is held at the end in a recess 55 of the housing extension piece 39.

Between the inner surface of the cylindrical housing part 1 9 and the outer surface of the cylindrical part of the threaded sleeve 5 an annular gap is provided in which a helical compression spring 57 is seated which coaxially encloses the threaded sleeve 5. The helical compression spring 57 bears on a radially inwardly protruding collar 59 at the hub end of the cylindrical housing part 19 on the one hand and on a circlip 61 inserted at the end of the threaded sleeve 13 remote from the hub on the other hand. The helical compression spring 57 thus initially stresses the deflection housing 17, guided rotatably and axially displaceably on the threaded sleeve 5, resiliently towards the multi-ratio hub 1. In the housing socket 23 there is further secured an insert 63 which can at the same time form a part of the wall of the housing socket 23.The insert 63 carries a tubular extension 65 engaging coaxially in the threaded sleeve 5. The tubular extension 65 with its end 67 facing the multi-ratio hub 1 forms a stop which abuts, when the hub is fitted, on the end face of the hub spindle 3 remote from the hub and holds the deflection housing 17, irrespective of the actual position of the threaded sleeve 5, in a reference position in relation to the hub spindle 3 and thus in relation to the gear-change elements of the multi-ratio hub 1. The deflection housing 17 in combination with the helical compression spring 57 thus forms a distance-compensating part which orients the detent positions, defined by the detent ball 51 and the detent recesses 47, in relation to the multi-ratio hub 1, irrespective of the position which the threaded sleeve 5 assumes in relation to the multi-ratio hub 1.

The force of the helical compression spring 57 is dimensioned so that it cannot overcome the force of the detent device, that is when the gear change rod 13 is locked it cannot rotate the arm 25 against the detent force of the spring 53. On the other hand the force of the helical compression spring 57 is greater than the force of the gear-change spring arranged in the multi-ratio hub 1 and pushing out the gear-change rod 13.

The helical compression spring 57 thus acts as storage spring which, when the gear-change rod 13 is locked, is stressed by way of the deflection housing 1 7 acting as distance-compensating element, by actuation of the actuating cable 37, and after elimination of the locking of the gear change rod 13 shifts the latter. Such a device permits the pre-selection of the gears even when the gear elements are locked by the drive torque.

By means of the hand lever the detent position of the bell-crank lever 27 is modified. Since the arm 25 rests on the gear-change rod 13 which is locked during the drive phase, the deflection housing 1 7 is moved axially away from the multi ratio hub 1, the stop force 67 lifting away from the end face of the hub spindle 3. The axial displacement distance of the deflection housing 1 7 is dimensioned so that it can compensate the axial gear-change movement over all gears.

The helical compression spring 57 is stressed by displacement of the deflection housing 1 7 in only one of the two directions of actuation of the actuating cable 37. In the opposite direction of actuation the nose 31 of the arm 25, abutting freely on the end face of the gear-change rod 13, can lift away from the gear-change rod 13 in the direction of an idle motion device, if the change function should be locked by reason of the drive loading of the gearing.

Claims

1. Gear-change device for a multi-ratio cycle hub (1) in the hub spindle (3) of which, provided at the end with an external threading, a gear-change element (13) is guided axially movably, comprising: a) a holder (5, 17) securable on the threaded end of the hub spindle (3), b) a manually actuatable actuating device (15) having an actuating cable (37) or the like subjectable to either tension or compression stress and guided movably approximately radially of the hub spindle (3) in the region of the holder (5,17), c) a deflection element (27) guided movably on the holder (5, 1 7), which couples the radially movable actuating cable (37) with the axially movable gear-change element (13), d) a detent device (47, 51) acting upon the deflection element (27) and held on the holder (5, 1 7), for the positioning of the actuating cable (37) in the position corresponding to the gear-change positions of the gear-change element (13), 'characterised in that on a securing part (5) of the holder securable on the hub spindle there is movably guided a distance-compensating part (17) which is arranged in the gear-change force path leading from the actuating cable (37) by way of the deflection element (27) to the gear-change element (13r, in such manner that it can compensate the gear-change path of the actuating cable (37) in relation to the gear-change element (13) at least for one gear, in that the distancecompensating part (17) is supported on a spring (57) acting against the distance-compensating movement, the force of which spring is greater than an oppositely directed force exerted by the gear-change element (13) in its gear-change movement upon the distance-compensating part, and in that the detent device (47, 51) defines the positions of the actuating cable (37) in relation to the distance-compensating part (1 7).

2. Gear-change device according to Claim 1, characterised in that the actuating part is formed as a threaded sleeve (5) which can be screwed on to the threaded end of the hub spindle (3), on which sleeve the distance-compensating part (17) is guided both axially displaceably and coaxially rotatably.

3. Gear-change device according to Claim 2, characterised in that the spring (57) acts in the axial direction of the threaded sleeve (5) and is stressed in between the threaded sleeve (5) and the distance-compensating part (17).

4. Gear-change device according to Claim 3, characterised in that the distance-compensating part (1 7) comprises a stop part (65) engaging in the threaded sleeve (5), which part, initially stressed by the spring (57), rests resiliently on the end face of the hub spindle (3).

5. Gear-change device according to one of Claims 2 to 4, characterised in that the deflection element is formed as a two-armed bell-crank lever (27) articulated to the distance-compensating part (17), which lever rests with its first arm (25) on a gear-change rod (13) issuing from the end of the threaded sleeve (5) remote from the hub, and the second arm (33) of which lever is connected with the actuating cable (37).

6. Gear-change device according to Claim 5, characterised in that the first arm (25) comprises open detent recesses (47) facing radially away from the pivot axis (29) and arranged in an arc of a circle about the pivot axis of the bell-crank lever (27), and in that a detent ball (51) co-operating with the detent recesses (47) is guided under resilient initial stress radially of the pivot axis (29) in a recess (49) of the distance-compensating part (17).

7. Gear-change device according to Claim 5 or 6, characterised in that the first arm (25) and the second arm (33) of the bell-crank lever (27) are offset in relation to one another in the direction of the pivot axis (29).

8. Gear-change device according to one of the preceding Claims, characterised in that an idle motion device is arranged in the forcetransmission path between the actuating cable (37) and the gear-change element (13) and transmits an actuating force only in the direction of actuation of the actuating cable stressing the spring, but not in the opposite direction of actuation.

9. A gear-change device substantially as described herein and with reference to the accompanying drawings.