SU925731A1 - Bicycle gearshift device - Google Patents

Description

(5) DEVICE FOR TRANSFERING BIKE TRANSMISSIONS

BACKGROUND OF THE INVENTION The invention relates to bicycle building, in particular, to devices for shifting bicycle gears. A gear shifting device is known, comprising two levers pivotally connected to the bracket and casing of the chain tensioning mechanism and forming the pivotal parallelogram, an elastic element in the form of two paired pin springs with oppositely directed free ends. The known device has a high reliability in operation due to the autonomous fastening of the spring, ensures uniform transfer of the force of the pin spring to the levers of the parallelogram when they are moved, so that “k. The forces of both spiral sections of the spring are folded and evenly transmitted to both levers of the ball parallelogram. However, this device has an increased size and weight due. making additional lugs in the middle part of the parallelogram arms and inserting additional fastening elements for fastening the springs. In addition, it has limited maintainability, since to replace outdated springs, it is necessary to knock out riveted pins, which leads to deformation of the levers and reduced durability of the device. The purpose of the invention is to reduce the size and weight of the device and ensure its maintainability. The goal is achieved by the fact that in the middle part of the levers there are recesses on the inner side, in which the lateral surfaces of the spiral sections of the springs are located. Figure 1 shows the proposed device for shifting the bicycle gears, a general view; 2, a spring for moving the arms of the articulated parallelogram, top view; fig.Z - the same, side view; on

FIG L - right arm of the hinge parallelogram, view from outside; Fig.5 section aa FHD.

The left 1 and right 2 levers, hinged on the bracket 3 used to attach the device to the bicycle, and the body of the tension mechanism of the chain 5 form a hinged parallelogram. On the bracket 3, the tide 6 is made, and on the case k, the oil outlet 7, which are stops limiting the movement to the right or left of the case k with the tension mechanism of the chain 5. In the middle part of the levers 1 and 2, on the inner side there are recesses 8, in KOTOpfeix lateral surfaces of the spiral sections of the spring 9. The spring is made in the form of two paired pin springs with oppositely directed bent free ends, which are somewhat shortened and have such a length so as to ensure the adherence of the lateral surfaces of the spiral plots to the surface of the recess 8. The size of the recesses is approximately equal to half the diameter of the spiral turns of the spring. This ensures that the turns are secured in the recesses.

On the right lever 2 on the inner side there are tides 10 with grooves in which plastic inserts 11 are located, which prevent screws from self-unscrewing 12, designed to adjust the range of movement of housing A with the tension mechanism of chain 5.

The bicycle shifter operates as follows.

Spring 9, interacting with the middle part and bent free ends with the left and right 2 levers, turns the parallelogram counterclockwise until it stops tide 7, body k in the butt-end adjustment

screw 12. At the same time, the spring does not limit the angle of rotation of the hinge parallelogram. When the parallelogram cable is tensioned, it is deflected in the opposite direction up to the stop of the screw 12 into the tide 6 of the bracket 3, while twisting both spiral sections of the spring 9. In this case, the gears are shifted.

This device for shifting bicycle gears reduces the size of the articulated parallelogram in width by more than half the diameter of the spiral section of the spring; a decrease in switch weight of approximately 10 g; the ability to repair a switch when the spring breaks down by simply removing it from the recess and installing a new spring without the use of additional fasteners.

Claims (1)

1. Application No. 2813721/27-P, class B 62 M 25/02, 1979 (prototype). g fug. 0ve