WO1998036960A1

WO1998036960A1 - Bicycle gear system

Info

Publication number: WO1998036960A1
Application number: PCT/AT1998/000036
Authority: WO
Inventors: Josef Prajczer
Original assignee: Josef Prajczer
Priority date: 1997-02-21
Filing date: 1998-02-20
Publication date: 1998-08-27
Also published as: ATA29197A; AT406365B

Abstract

The invention relates to a bicycle gear system, comprising a manually operated gear device the rotatable gear-shift handle (S) of which is connected by means of cables (A', B', C') to a gear device for several crank sprockets and a gear device for several rear sprockets. The rotatable gear-shift handle can be moved from a first gear shift position (I), in which it actuates both an actuating cable (B') for shifting the chain on the rear sprockets and an actuating cable (A') of a crank-sprocket guiding element (27), into a second gear shift position (II), in which position it actuates only the actuating cable (A') of the crank-sprocket guiding element (27), which is mounted in a sliding manner perpendicular to the bicycle frame between side parts (E) of said frame, to move the crank sprockets (30) connected to the guiding element into different gear positions. In the first gear-shift position (I), when the rear sprocket is shifted, the crank-sprocket guiding element (27) is displaced perpendicular in relation to the rear sprockets.

Description

Bicycle gear shift

The invention relates to a bicycle gear shift, with a manually operable switching device, the rotatable switching handle is connected via cables with a switching device for several crank sprockets and with a switching device for several rear axle sprockets.

Bicycle gear shifts of this type, which are known in various designs, are associated with the deficiency that the bicycle chain runs obliquely from the respective crank sprocket to the respectively associated rear axle sprocket, which results in material wear and an increased effort. In addition, it is not possible in practice in the known gear shifts because of the inclination of the chain to shift a large number of gears, in particular over 20 gears, because the chain tends to skip because of the lateral force components exerted by the large crank sprockets.

The invention aims to provide a bicycle gear shift of the type specified in the introduction, which avoids the inclination of the bicycle chain between the crank sprockets and the rear axle sprockets and enables a perfect shifting of all gears, in particular of 28 gears.

This object is achieved in that the rotatable control handle of the switching device in the axial direction against a spring bias from a control handle position, in which it with a first cable guide pulley, which is attached to an actuating cable of the switching device for the chain change in the area of the rear axle sprockets, and with a second cable guide pulley, which guides an actuating cable of a crank sprocket guide element attached to it, is in engagement with common rotation, can be moved into a second control handle position, in which it is disengaged from the first cable guide pulley and only with the second cable guide pulley for the actuating cable of the in the bicycle frame transverse direction between side frame parts slidably arranged crank sprocket guide element for common rotation to offset the with the guide element ent connected crank sprockets in different switching positions, wherein in the first shift handle position when switching the rear axle sprockets, the crank sprocket guide element is moved in the transverse direction relative to the rear axle sprockets, so that the chain is guided in a straight line between the respective crank sprocket and the associated rear axle sprocket is guaranteed.

This construction eliminates any skewing of the bicycle chain with respect to the rear axle sprockets, thereby protecting the material and saving force that would otherwise be lost due to the friction between the bicycle chain and the associated sprocket. At the same time, the perfect shifting of all gears of the gear shift is achieved because the crank sprockets have sufficient freedom of movement. A preferred embodiment of the invention is characterized in that the crank sprocket guide element has a sliding part which is mounted on a sliding guide rod so as to be non-rotatable relative to it in the transverse direction of the frame, which is acted upon by the actuating cable attached to it and is provided with a fork which engages with a crank guide ring, which is mounted together with the crank sprockets on a crankshaft sleeve which is slidably mounted on the crankshaft.

According to a further feature of the invention, a further sliding guide rod extends between the crankshaft and the rear axle sprockets between the frame side parts, on which a chain guide part is non-rotatably slidably supported, which is acted upon by an actuating rope which, together with the actuating rope of the crank sprockets, via the rope guide pulley in the first shift handle position is operated.

The invention is explained in more detail below using an exemplary embodiment with reference to the drawings, in which: FIG. 1 shows a schematic side view of a part of the bicycle frame /

FIG. 2 shows a schematic front view of the frame part according to FIG. 1; Figure 3 is a schematic section of the frame part along the line III-III in Fig. 1.

Fig. 4 is a plan view of the frame part of Fig.l; 5a, 5b, 5c show a schematic axial section of the shift handle and the associated shift parts of the gear shift;

FIG. 6 shows a highly schematic top view of FIG. 5a;

7 shows a schematic cross section through the housing of the switching device along the line VII-VII in FIG. 5b; FIGS. 8a to 8d details from FIG. 5a; 9a, 9b details of the control handle in axial section;

10 is a highly schematic top view of the functional diagram of the gear shift according to the invention;

11 details of the crank ring guide; Figures 12a and 12b details of a chain guide.

13 shows a detail of the crank ring guide, and

Fig. 14 in section a further detail of the crank ring guide.

The bicycle frame shown only partially and in a highly schematic manner in FIGS. 1 to 4 has a bicycle fork A and a bicycle fork guide B connected to a handlebar C, as is common with every bicycle. The bicycle fork guide B is connected via a connecting rod D to a bicycle saddle holder I and via fork-shaped frame connecting rods E to a holder F for a crankshaft and a crank bearing G. The crankshaft bracket F is connected via frame connecting rods H to the saddle bracket I, which in turn is connected via struts J to a rear axle bracket N, from which frame parts E 'extend to the bracket F. Between the frame connecting rods E and H are in the transverse direction of the frame slide rod guides L and M are provided for slide circuit elements to be explained.

The actual bicycle gearshift, which is intended for 28 gears, has 4 crank sprockets and 7 rear axle sprockets and, according to FIGS. 5 to 8, essentially has the following components: a circuit housing part 1, which is fixed to a handlebar 3 by means of screws 1 ', and a circuit housing - part 2, which is connected 1 "ver to the housing part 1 ^¬ means of screws. are in the housing part 1, as in detail Fig. 5c shows gear position hollows 13 and in the housing part 2 Gangpositi ^¬ onsmulden 14 is formed. On the outside of the housing is a position scale PS (Fig. 10) provided for the individual gear positions or the position of actuating cables A ', B' C of the gear shift.

5 and 7 with pairs of axially spaced, diametrically opposed teeth 20 'and 21' for the further transport of guide disks 15, 16 rotatably arranged in the housing 1, 2 for the actuating cables A ', B ', C. In the first control handle position I (FIG. 5a) the cables B ', C (FIGS. 6, 7) can be actuated or switched by means of the disc 15 and at the same time the cable A' by means of the disc 16. The cables B ', C actuate a conventional switching device 23 only indicated in FIG. 1 in the area of the rear axle N for seven rear axle sprockets, not shown, and a chain guide element 24 to be described. With the aid of the cable A ', four crank sprockets 30 are axially displaced in a manner to be described, but in the process the chain is not switched.

In the second control handle position II (FIG. 5b), only the cable A 'can be actuated or switched by means of the disk 16 by pulling out (arrow S ") and rotating the control handle S. This cable A' actuates a slide switch to be described below. tion element 27 (Fig. 10, 12) for the crank sprockets 30, such that these sprockets 30 are set in the transverse direction in the desired shift position or gear position. A spring 6 provided in the shift handle S pulls the shift handle S in the direction against the handlebar 3 9a, 9b, which show the end of the control handle, is fixed on the handlebar 3 and connected to the control handle S by spring holders 7. The spring supports 7 are formed by swivel hooks mounted on the control handle S by means of screws 8 - Gripping screwed control handle screw 9 is used to pivot and fix the spring holders 7, which keep the spring 6 tensioned. The disk 15 guiding the cables B ', C is provided with a semicircular elevation or a tooth 15' (FIG. 5c, FIG. 8b) which fits exactly into the position troughs 13 of the housing part 1. The disk 15 should not be too difficult to be conveyed into the individual position troughs 13 by means of the control handle S. In the disc 15 there are also the matching recesses 20 for the two engagement teeth 20 '(FIGS. 5a, 8c) of the control handle S. The number of recesses 20 depends on the number of crank sprockets.

The shift cables A ', B', C, which serve to adjust the individual positions of the chain K, are fixed to the disks 15, 16 with the aid of cable fixings 17. The shift cables A ', B', C are actuated by means of the shift handle S as a result of the engagement of the teeth 15 ', 16' of the disks 15, 16 in the gear position recesses 13, 14. Between the disks i5, 16 a spring 18 is provided, the spring force directed against the housing parts 1, 2 may neither be chosen too strong nor too weak in order to enable a comfortable change of the switching positions.

A certain play 19 (FIG. 8c) is provided between the handlebar 3 and the control handle S. There are ten position recesses 20 (FIG. 8b) for the teeth 20 '(FIG. 5a) of the control handle S on the disk 15 diametrically opposite one another, and on the disk 16 there are in each case a semicircular elevation or a tooth 16' for Determining the positions of the shift cable A 'in the position troughs 14 of the housing part 2. The number of position troughs 14 provided for the engagement of the tooth 16' in the housing part 2 depends on the number of crank sprockets and the rear axle sprockets and is 10 in the present example.

As FIGS. 5a and 8d show, a circular recess 21 is provided in the housing part 2 for the reception or movement associated with the switching handle teeth 21 '(FIGS. 5a, 5b, 8d). This recess 21 extends in the housing part 2 axially to a depth which is slightly more than the axial extent of the teeth 20 'so that these teeth 20' in the Shift handle position II come out of engagement with the disc 15.

10 and 11 show a front crank ring guide 22 for displacing the crank sprockets 30 and thus for changing the chain K on the crank sprockets 30 when the rear axle switching device is not actuated. The crank ring guide 22 is actuated by means of the cable A 'after pulling out the control handle S up to the stop (FIG. 5b) in the switching position II. The rope positions previously reached with ropes B 'and C remain the same. Due to the inclined position of the chain K when the crank sprockets 30 are displaced, the chain K changes further by one position or by one crank sprocket 30 depending on the rotation of the control handle S in the clockwise or counterclockwise direction. When all shift cables A ', B', C are actuated simultaneously with the aid of the disks 15, 16 in the shift position I of the shift handle S, the crank sprockets 30 are only moved in the transverse direction together with the chain changing on the rear axle sprockets, without the chain K being present changes on the crank sprockets.

The crank ring guide 22 (FIGS. 10, 11) consists of a sliding part 22 'which slides on the oval cross-section sliding guide rod L and guide arms 22''connected to the sliding part 22'. To avoid excessive friction, there are small 22 '' on the two guide arms Bearing balls 22 "'provided. In addition, a device 22 ^1V is located on the sliding part 22' for fixing the rope A '.

A rear chain positioning device or switching device 23, which is assigned to the rear axle sprockets and is only indicated schematically in FIG. 1, is designed as in a conventional bicycle gearshift and is therefore not explained. 10, the chain K is brought to the desired rear axle sprocket when the control handle S is rotated clockwise or counterclockwise in the control handle position I (FIG. 5a) by actuating the switching device 23.

A central chain guide 24 (FIGS. 10, 12a, b) which is actuated simultaneously by means of the shifting cable C is used for guidance the chain K when switching the rear axle sprockets. The chain guide 24 has a sliding piece 24 'with a fastening 24 "for the cable C and two curved arms, as shown in FIGS. 12c, 12b, and slides around on the sliding guide rod M with an oval cross section when changing the chain position in the transverse direction of the frame to prevent the slider 24 'from rotating on the slide guide rod M which extends between the side frame parts H (cf. FIG. 4).

Rope setting elements 25 on the housing 1, 2 enable fine adjustment of the ropes A ', B', C in the event of extreme temperature fluctuations and expansion loads (cf. FIGS. 6, 7).

The guide ring 27 of the crank ring guide 22 assigned to the crank sprockets 30 is brought into the desired position according to FIG. 11 with the aid of the actuating cable A '. The guide ring 27 has no teeth and also serves as a chain guard. 13, there are recesses 27 'against the center or radially inwards, which engage in the teeth 29' of a crankshaft sleeve 29 which supports the crank ring teeth 30. The crankshaft 28 is provided with teeth 28 'which engage in recesses 29 "of the crankshaft sleeve 29.

With the help of the pedals P, the crankshaft 28 and crankshaft sleeve 29, the sprockets and the chain K, the wheels R of the bicycle move. As shown in FIGS. 13, 14, the crankshaft 28 is designed as a square at both ends in order to be able to fasten the pedals P, and has threaded holes at both ends for fastening the pedal arms by means of screws P '.

The crank sprockets 30 themselves are attached to the crankshaft sleeve 29 as well as the crank guide ring 27. In FIGS. 10, 13, the crank sprockets 30 are provided with external teeth for the transport of the chain K and with a center or. Inner recess 30 'for the engagement of teeth 29' of the crankshaft sleeve 29 designated. Threaded holes 36 are provided for fixing the rings 27, 30 to one another and to a stop 37 of the crankshaft sleeve 29.

With four crank sprockets 30 according to the exemplary embodiment shown, the guide ring 27 and a given distance between the guide ring 27 and the ball bearing G, the stood "x" (Fig. 10) between the crankshaft sleeve 29 and the opposite crank bearing G so large that ten switching positions remain free. A shift position or gear position means a distance between two sprockets 30. The crank sprockets 30 and the Hinterachszahnkränze must be coordinated with each other ^¬ that no position or no gear gives the same translation.

With 31 are rope sliding or pulleys and with 32 one

Rope sheath indicated. 33 each designates a cable sheathing holder and 34 cable fixings on the ring guides.

The 28 switching positions that are possible with the circuit according to the invention are described in detail below. Here mean:

Control handle position I: ropes A '/ B' + C can be actuated; Control handle position II: only rope A 'can be operated (control handle is pulled out as far as it will go).

The individual positions can be set by turning the control handle S.

POSITIONS: 1-7 = switch position I

7-8 = shift handle position II: change sprockets 30;

8-14 = shift handle position I from 8-2 by turning the handle;

14-15 = gear lever position II: sprockets 30 from position 2 to position 3

15-21 = control handle position I: the positions can be switched from 3 to 9;

21-22 = control handle position II: from position 9 to position 10; 22-28 = switch position I: from position 10 to 4

28-22 = control handle position I: from position 4 to 10

22-21 = control handle position II: from position 10 to 9

21-15 = switch position I: from position 9 to 3

15-14 = control handle position II: from position 3 to 2 14-8 = control handle position I: from position 2 to 8

8-7 = control handle position II: from position 8 to 7

7-1 = control handle position I: from position 7 to 1

The quick version from 1.-28. and from 28.-1. Gear. 1-7 = Shift handle position II: the position from 1 to 2 7.-14. = Shift handle position II: the position from 2 to 3 14.-21. = Shift handle position II: the position from 3 to 4 21.-28. = Shift handle position II: the position from 4 to 5 28-21. = Shift handle position II: the position from 5 to 4 21.-14. = Shift handle position II: the position from 4 to 3 14.-7. = Shift handle position II: the position from 3 to 2 7.-1. = Shift handle position II: the position from 2 to 1 The 28 gear shift options are shown schematically below.

^α 3rd gear:

4 ό. gear:

7

3 10th gear

13th gear :.

1

i.5.Ganσ:. ^ =. lό. Course: ____, _ 17th course:

18th course. r--. ^{=== 19th} gear: _n - ~ —20th gear;

21st gear: -

22nd gear: == 23rd gear: == ^ 24th gear:

25th gear: _ = 26th gear: ₌₌₌₌ . z.27.gang :.

? 8th gear: ^• === 2 ₌

In the context of the invention, five crank sprockets and six rear axle sprockets could also be provided at the front.

Claims

Claims:

1. Bicycle gear shift, with a manually operable switching device, the rotatable switching handle via cables with a switching device for several crank sprockets and a switching device for several rear axle sprockets in connection, characterized in that the rotatable switching handle (S) of the switching device in the axial direction against a spring preload from a shift handle position (I), in which it has a first rope guide pulley (15), which carries an attached operating cable (B ') of the shifting device for the chain change in the area of the rear axle sprockets, and a second rope guide pulley (16), which a attached to this actuating cable (A ') of a crank gear guide element (27), which is engaged in common rotation, can be moved into a second control handle position (II), in which it is disengaged from the first cable guide pulley (15) and only with the second rope guide tion disc (16) for the actuating cable (A ') of the crank sprocket guide element (27) slidably arranged in the bicycle frame transverse direction between the side frame parts (E) on common rotation to move the crank sprockets (30) connected to the guide element (27) into different switching positions in Engagement is present, in the first shift handle position (I) when switching the rear axle sprockets the crank sprocket guide element (27) is moved in the transverse direction relative to the rear axle sprockets, so that the chain (K) is guided in a straight line between the respective crank sprocket (30 ) and the assigned rear axle sprocket is guaranteed.

2. Bicycle gearshift according to claim 1, characterized in that the cable guide disks (15, 16) which can be connected to a common rotation with the shift handle (S) are each provided with latching lugs (15 ', 16') which are located in position latching recesses (13, 14) snap into the housing (1, 2) of the switching device under spring force.

3. Bicycle gear shift according to claim 2, characterized in that between the cable guide disks (15, 16) the disks apart and spring (18) pressing against the position locking recesses (13, 14) is provided.

4. Bicycle gear shift according to one of claims 1 to 3, characterized in that the shift handle (S) surrounds the handlebar (3) and is biased by a spring (6) in the second shift handle position (II).

5. Bicycle gear shift according to claim 4, characterized in that the spring (6) at the end of the handlebar (3) fixed and held on the shift handle (S) by pivotally mounted on this holder (7) which is screwed into the end of the shift handle (9) are engageable with the spring.

6. Bicycle gear shift according to one of claims 1 to 5, characterized in that the crank sprocket guide element (22) on a sliding guide rod (L) relative to this non-rotatably mounted in the transverse frame direction sliding part (22 '), which of the is attached to this attached operating cable (A ') and is provided with a fork (22 ") which engages with a crank guide ring (27) which is mounted together with the crank ring gear (30) on a crankshaft sleeve (29) which is slidably mounted on the crankshaft (28).

7. Bicycle gear shift according to one of claims 1 to 6, characterized in that between the crankshaft

(28) and the rear axle sprockets, a further sliding guide rod (M) extends between the frame side parts, on which a chain guide part (24) is non-rotatably and slidably mounted, which is acted upon by an actuating cable (C), which together with the actuating cable (B ') of the crank sprockets (30) is actuated via the cable guide disc (15) in the first control handle position (I).