FR2776981A3 - Mountain bike suspension - Google Patents

Abstract

The suspension is composed of a frame (1) with pivots (2,3) on which are fixed small connecting rods (7,8). The rods are fixed on the pivots (4,5) of the oscillating arm (6) so that it oscillates in a rising curve combined with a rearwards translation. The shock absorber operates by clamping between the oscillating arm and the connecting rod (7).

Description

I The present invention is a deformable parallelogram system

  intended to guide the swinging arm of a V.T.T with integral suspensions.

  Current parallelograms support the rear wheel or the rear triangle so that they oscillate vertically relative to the bicycle. Anterior to the system for which protection is sought consists in oscillating the arm according to a curve dictated by the two links constituting the parallelogram. The rear center distance then decreases during the compression phase and the shock absorber is always fixed between the swing arm

and the frame.

  The system according to the invention is a new concept from that previously cited. It consists of a V.T.T frame with two bearing cages. On each of them are attached rods which support the swingarm, also provided with two bearing cages. The link located furthest in front of the frame is at the start of the movement in an almost vertical position and lowers during its rotation

  backward exerted by the depression of the suspension.

  The link located near the crankset describes the same rotation but straightening. The combined movements of the two links make the arm describe an upward tilt in its rear part as well as a rearward translation. The accompanying drawings illustrate the invention:

  Figure I shows the system according to the invention.

  Figure 2 shows the system in operation.

  With reference to these drawings, the system is in the form of a

  frame (1) of V.T.T comprising two pivots (2) and (3) mounted on bearings.

  Two links (7) and (8) are fixed respectively on the pivots (2) and (3) of the frame and on the pivots (4) and (5) of the swinging arm (6), thus forming the

  deformable parallelogram which allows the arm to oscillate.

  The link (7) located in front of the frame receives the shock absorber (9) which

  works by pinching with the swinging arm (6).

  The operation (figure 2) is done by the rotation towards the land of

  links (7) and (8) under the action of the force exerted on the swinging arm.

  The rod (7) descends during its rotation and actuates the shock absorber.

  The link (8) describes an upward movement, which combined with that of the link (7), created the tilting of the swing arm upwards at

  rear wheel attachment level.

  This system makes it possible to obtain a clearance at the rear wheel very

  important and variable progressiveness in the rotation of the link (7).

  The rearward translation caused during the movement by the movement of the links increases the chain length between the crankset and the rear wheel. When the suspension is pressed hard, the extension of the rear center distance exerts traction on the chain on the freewheel. The energy lost when the suspension is pressed in by pedaling is thus restored under the form of traction on the free wheel of the rear wheel. The performance of the V.T.T is thus maintained when the suspension

works.

  The large travel of this system mainly targets

V.T.T of descents.

Claims (4)

  1) Suspension system for V.T.T with parallelogram characterized by the presence of a deformable parallelogram which connects the frame (1) to the swinging arm (6). The parallelogram consists of two pivots (2) and (3) on the frame and two other pivots (4) and (5) on the swing arm,   all connected by the links (7) and (8).   2) System according to claim I characterized by the clamping operation of the damper (9) between the link (7), located in front of the frame, and the swing arm (6).   3) System according to claim 1 characterized by the positioning of the link (7) relative to the frame (1) allowing it to rotate, when the suspension is driven, only rearward in a downward movement of the pivot (4).   4) System according to claim I characterized by the positioning of the rod (8) relative to the frame (1) allowing it to rotate, when the suspension is pressed, only rearward in a upward movement of the pivot (5).