Cycle rear suspension system

A rear suspension system for a cycle, said cycle having a main frame including a rearwardly and downwardly extending down tube, a generally upright seat tube, and a bottom bracket shell, said suspension system comprising:

• a pivotable rear frame assembly behind the main frame including elongated swing arm means for supporting a rear wheel for up and down movement relative to the main frame and being pivotally connected at its front end portion to the main frame, the swing arm means having means at the rear end portion for supporting a rear wheel for up and down movement relative to the main frame, said rear frame assembly also including elongated chain stay means extending forwardly from the rear end portion of the swing arm means and being movable therewith for controlling movement of the swing arm means;
• a shock absorber assembly supported by the main frame alongside the down tube and having a coupling means which is movable along an axis generally parallel to the down tube for applying a load from the swing arm means to the shock absorber assembly, said shock absorber assembly including spring means urging said coupling means in one direction along the down tube, and means for dampening movement of said coupling means;
• and
• connecting and guiding means connecting the chain stay means with the coupling means on an underside of the main frame;
• whereby an upward impact load on the rear frame assembly displaces it upwardly and deflects the spring means in a direction opposite said one direction, and whereby further, movement of the rear frame assembly is dampened.

A rear suspension system for a cycle, said cycle having an upright main frame including a down tube, a seat tube, and a bottom bracket shell, said main frame having opposite sides, said suspension system comprising:

• a pair of rearwardly extending swing arms pivotally connected at their front ends to said opposite sides of said main frame, each swing arm having at its rear end a rear fitment adapted to support a rear wheel for up and down movement relative to the frame;
• a tubular shock absorber assembly supported by the down tube and having a linearly movable coupling means extending rearwardly and downwardly therefrom for applying a load from the swing arm means to the shock absorber assembly, said shock absorber assembly including spring means urging said coupling means in a forward and upward direction, and means dampening movement of said coupling means in either direction;
• a pair of elongated flexible chain stays, each extending forwardly from a corresponding one of said rear fitments;
• and
• bell crank means having the apex thereof pivotally mounted on the underside of the frame and having two angularly spaced arms pivotally connected respectively to the forward ends of the chain stays and to said coupling means;
• whereby upward movement of the chain stays with the swing arms moves the coupling means of the shock absorber assembly through the bell crank means and such movement is resisted by longitudinal deflection of the spring means and by transverse deflection of the chain stays, whereby movement of said swing arms is dampened in both up and down directions, and whereby further upward force on said swing arms is reacted through said spring means and chain stays as a largely downward force on the frame.

A rear suspension system for a cycle having a main frame with a seat supporting member located forwardly of a rear wheel and with a forwardly and upwardly inclined down tube, said suspension system comprising:

• a pivotable rear frame assembly behind the main frame including elongated swing arm means for supporting a rear wheel for up and down movement relative to the main frame being pivotally connected at its front end to the main frame and having means at the rear end for supporting a rear wheel, said rear frame assembly also including elongated chain stay means extending forwardly from the rear end of the swing arm means and being movable therewith for controlling movement of the swing arm means;
• a shock absorber assembly comprising elongated, fluid-damped piston and cylinder means supported at one end by the down tube forwardly of the seat supporting member and having coupling means at the other end linearly movable in opposite directions along the down tube for receiving and dampening impact loads applied to the rear frame assembly;
• spring means urging said coupling means in one direction;
• and
• bell crank means pivotally mounted respectively to the underside of the main frame, to the coupling means, and to the chain stay means, a toggle link pivotally connected between the bell crank means and the coupling means to maintain a positive connection between the bell crank means and the coupling means throughout a range of pivotal movement of the bell crank means and corresponding linear movement of the coupling means;
• whereby an upward impact load on the rear frame assembly displaces it upwardly and deflects the spring means in a direction opposite said one direction, and whereby further, movement of the rear frame assembly is dampened.

A rear suspension system for a cycle having a main frame with a forwardly and upwardly inclined down tube, said suspension system comprising:

• a vertically movable rear frame assembly having means for supporting a rear wheel, and means connecting the rear frame assembly to the main frame for up and down movement relative to the main frame;
• a shock absorber assembly comprising elongated, fluid-damped piston and cylinder means supported at one end by the main frame and having coupling means at the other end movable in opposite directions along the down tube for receiving and dampening impact forces generated by movements of the rear frame assembly;
• spring means urging said coupling means in an upward direction;
• and
• a bell crank pivotally connected respectively to the main frame, to the rear frame assembly, and to the coupling means enabling the coupling means to be movable downwardly against the urgence of the spring means in response to upward movement of the rear frame assembly, and said bell crank enabling the spring means to move the coupling means upwardly in response to downward movement of the rear frame assembly;
• whereby an upward, impact load on the rear frame assembly displaces the rear frame assembly upwardly and deflects the coupling means in a largely downward direction while the impact load is reacted through said spring means as a largely downward force component on the main frame, and whereby further, movement of the rear frame assembly relative to the main frame is damped.