GB1570520A

GB1570520A - Cycles provided with multi-speed chain and sprocket transmissions

Info

Publication number: GB1570520A
Application number: GB4645176A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1975-11-07
Filing date: 1976-11-08
Publication date: 1980-07-02
Also published as: CH607823A5; FR2330583A1; DE2648928A1; NL7611882A; ES453104A1; JPS5275740A; FR2330583B1

Abstract

The device is intended to facilitate removal of the rear wheel by first transferring the chain from the sprocket wheel onto a support attached to the seatstay. For this purpose the device comprises a crescent-shaped guide (2) which guides and supports the chain and is attached to the inside of the end of the chainstay (1) and a small shift control lever (11) mounted on the frame (15). A pawl (16) is mounted on said lever (11) and oscillates freely against the action of a spring. A fixed bracket (21) is also provided which has two ratchet gear teeth (19, 20), said pawl (16) being able to engage with said teeth. By moving the pawl (16) the small shift control lever (11) can be turned beyond the stop formed by the first tooth (19), thereby transferring the chain (5) onto the crescent-shaped guide (2). <IMAGE>

Description

(54) IMPROVEMENTS IN OR RELATING TO CYCLES PROVIDED WITH MULTI-SPEED CHAIN AND SPROCKET TRANSMISSIONS (71) I. TULLIO CAMPAGNOLO, an Italian citizen, of Corso Padova 168-36100 Vicenza, Italy. do hereby declare the invention, for which I pray that a patent may be granted to me. and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a cycle having a multi-speed chain and sprocket transmission of the kind in which change speed operations are effected by the chain being transferred by a derailleur from one to another of several rear sprockets of different diameters.

The object of the invention is to facilitate the operations of removing and replacing the rear wheel of such a cycle by providing improved means for preventing the rear end part of the driving chain thereof from collapsing in a disorderly manner when the rear wheel is removed.

With this object in view, the present invention provides a cycle having a multispeed chain and sprocket transmission of the kind referred to wherein an arcuate chain support is mounted on the frame of the cycle adjacent and substantially in coaxial alignment with the smallest diameter rear sprocket and a control lever assembly is mounted on a front part of said frame, said control lever assembly including a control lever, which is operatively connected by a control cable to the derailleur and is movable through a range of gear-selecting positions in each of which it causes the derailleur to effect engagement of the chain with a corresponding one of the rear sprockets, and further including a pawl carried by the control lever and resiliently biased towards a position in which it cooperates with a ratchet provided on a fixed part of the control lever assembly in the region of one end of the control lever travel and the arrangement being such that pivotal movement of the control lever in the direction to effect the transfer of the chain from a larger diameter rear sprocket to a smaller diameter rear sprocket is limited by engagement of the pawl with a tooth of said ratchet so as to prevent movement of the control lever in said direction beyond the gear-selecting position in which it causes the chain to be engaged with the smallest diameter rear sprocket, except when the pawl is manually disengaged from said tooth of said ratchet to enable the control lever to be moved to an extreme end position thereby causing the chain to be transferred by the derailleur from the smallest diameter rear sprocket to the arcuate chain support.

A preferred embodiment of the invention will now be described in further detail, by way of example with reference to the accompanying drawings in which: Figure 1 is a side view of an arcuate chain-supporting rail fixed to one of the tines of the rear fork of a cycle, Figure 2 is a front elevation of the assembly shown in Figure 1, Figure 3 is a plan view of a change-speed gear control means, Figures 4 and 5 are side views of the change-speed gear control means of Figure 3 in two different positions of use respectively, Figure 6 is a fragmentary perspective view illustrating the condition of the driving chain of a known cycle having a transmission of the kind initially referred to when the rear wheel of the cycle is removed, in the case where the cycle has no arcuate chainsupporting rail and Figure 7 is a view similar to that of Figure 6 illustrating the condition of the driving chain of such a cycle when the rear wheel thereof is removed, in the case where the cycle is provided with an arcuate chainsupporting rail corresponding to that shown in Figures 1 and 2.

Referring to Figures 1 and 2, secured against the inner side of the right hand tine of the rear fork 1 of a bicycle is an arcuate rail 2 which has an angular extent of more than 1800 and is provided with two enlargements 3 formed respectively with countersunk bores for the reception of two fixing screws 4. The arcuate rail 2 is parallel to and substantially in coaxial alignment with the rear sprockets of the bicycle and is located adjacent the outermost and smallest of the said rear sprockets.

As shown in Figure 7, the transmission chain 5 of the bicycle (which normally. in known bicycles, collapses and drops onto the ground as shown in Figure 6 when the rear wheel is removed, thereby becoming soiled or entangled) can be transferred directly from the outermost and smallest rear-sprocket onto the arcuate rail 2, before the rear wheel is removed, so that the transmission chain 5 is maintained in a tensioned condition while being supported on the bicycle frame 1 as shown in Figure 7, even when the rear wheel is removed.

To obtain the transference of the chain 5 onto the arcuate rail 2, so that it is supported in the position shown in Figure 7, use is made of an improved change-speed gear control means shown in Figures 3 to 5. This control means comprises a control lever 11 mounted for rotation against high frictional resistance on a pin 12 fixed to a clamp 14 which is secured to the front tube 15 of the bicycle frame.

A pawl 16 is pivoted on a pin 17 on the control lever 11 and is subject to the action of a spring 18 which normally keeps it in the position shown in Figures 4 and 5 in which it engages a selected tooth 19 or 20 of a ratchet 21 fixed to the clamp 14.

In the position shown in Figure 4 and in the positions obtained by rotating the lever 11 anticlockwise from this position, the lever 11 controls the speed-change gear in the usual manner. This lever 11, however, cannot rotate clockwise beyond the position shown in Figure 4 as long as the pawl 16 engages the tooth 19.

If. however, the cyclist acts so as to cause anticlockwise rotation of the pawl 16 about the pin 17, against the action of the spring 18, he can continue the rotation of the lever 11 beyond the tooth 19 (and as far as the position in which the pawl 16 engages the tooth 20). By such rotation, he effects the desired transfer of the chain 5 onto the arcuate rail 2, thereby enabling the rear wheel of the bicycle to be removed and remounted without any risk of the chain collapsing or becoming entangled, damaged or soiled. To restore the bicycle to a running condition, it will then be sufficient for the cyclist to rotate the lever 11 anticlockwise until the pawl 16 clicks beyond the tooth 19, whereby the chain 5 is returned from the idle condition shown in Figure 7 to a working condition in engagement with one of the rear sprockets of the bicycle.

WHAT WE CLAIM IS: 1. A cycle having a multi-speed chain and sprocket transmission of the kind in which change speed operations are effected by the chain being transferred by a derailleur from one to another of several rear sprockets of different diameters, wherein an arcuate chain support is mounted on the frame of the cycle adjacent and substantially in coaxial alignment with the smallest diameter rear sprocket and a control lever assembly is mounted on a front part of said frame, said control lever assembly including a control lever, which is operatively connected by a control cable to the derailleur and is movable through a range of gearselecting positions in each of which it causes the derailleur to effect engagement of the chain with a corresponding one of the rear sprockets, and further including a pawl carried by the control lever and resiliently biased towards a position in which it cooperates with a ratchet provided on a fixed part of the control lever assembly in the region of one end of the control lever travel and the arrangement being such that pivotal movement of the control lever in the direction to effect the transfer of the chain from a larger diameter rear sprocket to a smaller diameter rear sprocket is limited by engagement of the pawl with a tooth of said ratchet so as to prevent movement of the control lever in said direction beyond the gear-selecting position in which it causes the chain to be engaged with the smallest diameter rear sprocket, except when the pawl is manually disengaged from said tooth of said ratchet to enable the control lever to be moved to an extreme end position thereby causing the chain to be transferred by the derailleur from the smallest diameter rear sprocket to the arcuate chain support.

2. A cycle according to claim 1, wherein the extreme end position of the control lever is defined by abutment of the pawl with a second tooth of said ratchet.

3. A cycle according to claim 1 or 2, wherein the arcuate chain support is formed by a curved rail.

4. A cycle according to any of the preceding claims, substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Referring to Figures 1 and 2, secured against the inner side of the right hand tine of the rear fork 1 of a bicycle is an arcuate rail 2 which has an angular extent of more than 1800 and is provided with two enlargements 3 formed respectively with countersunk bores for the reception of two fixing screws 4. The arcuate rail 2 is parallel to and substantially in coaxial alignment with the rear sprockets of the bicycle and is located adjacent the outermost and smallest of the said rear sprockets. As shown in Figure 7, the transmission chain 5 of the bicycle (which normally. in known bicycles, collapses and drops onto the ground as shown in Figure 6 when the rear wheel is removed, thereby becoming soiled or entangled) can be transferred directly from the outermost and smallest rear-sprocket onto the arcuate rail 2, before the rear wheel is removed, so that the transmission chain 5 is maintained in a tensioned condition while being supported on the bicycle frame 1 as shown in Figure 7, even when the rear wheel is removed. To obtain the transference of the chain 5 onto the arcuate rail 2, so that it is supported in the position shown in Figure 7, use is made of an improved change-speed gear control means shown in Figures 3 to 5. This control means comprises a control lever 11 mounted for rotation against high frictional resistance on a pin 12 fixed to a clamp 14 which is secured to the front tube 15 of the bicycle frame. A pawl 16 is pivoted on a pin 17 on the control lever 11 and is subject to the action of a spring 18 which normally keeps it in the position shown in Figures 4 and 5 in which it engages a selected tooth 19 or 20 of a ratchet 21 fixed to the clamp 14. In the position shown in Figure 4 and in the positions obtained by rotating the lever 11 anticlockwise from this position, the lever 11 controls the speed-change gear in the usual manner. This lever 11, however, cannot rotate clockwise beyond the position shown in Figure 4 as long as the pawl 16 engages the tooth 19. If. however, the cyclist acts so as to cause anticlockwise rotation of the pawl 16 about the pin 17, against the action of the spring 18, he can continue the rotation of the lever 11 beyond the tooth 19 (and as far as the position in which the pawl 16 engages the tooth 20). By such rotation, he effects the desired transfer of the chain 5 onto the arcuate rail 2, thereby enabling the rear wheel of the bicycle to be removed and remounted without any risk of the chain collapsing or becoming entangled, damaged or soiled. To restore the bicycle to a running condition, it will then be sufficient for the cyclist to rotate the lever 11 anticlockwise until the pawl 16 clicks beyond the tooth 19, whereby the chain 5 is returned from the idle condition shown in Figure 7 to a working condition in engagement with one of the rear sprockets of the bicycle. WHAT WE CLAIM IS:

1. A cycle having a multi-speed chain and sprocket transmission of the kind in which change speed operations are effected by the chain being transferred by a derailleur from one to another of several rear sprockets of different diameters, wherein an arcuate chain support is mounted on the frame of the cycle adjacent and substantially in coaxial alignment with the smallest diameter rear sprocket and a control lever assembly is mounted on a front part of said frame, said control lever assembly including a control lever, which is operatively connected by a control cable to the derailleur and is movable through a range of gearselecting positions in each of which it causes the derailleur to effect engagement of the chain with a corresponding one of the rear sprockets, and further including a pawl carried by the control lever and resiliently biased towards a position in which it cooperates with a ratchet provided on a fixed part of the control lever assembly in the region of one end of the control lever travel and the arrangement being such that pivotal movement of the control lever in the direction to effect the transfer of the chain from a larger diameter rear sprocket to a smaller diameter rear sprocket is limited by engagement of the pawl with a tooth of said ratchet so as to prevent movement of the control lever in said direction beyond the gear-selecting position in which it causes the chain to be engaged with the smallest diameter rear sprocket, except when the pawl is manually disengaged from said tooth of said ratchet to enable the control lever to be moved to an extreme end position thereby causing the chain to be transferred by the derailleur from the smallest diameter rear sprocket to the arcuate chain support.