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Variable speed reciprocating lever drive mechanism

  • US 3,954,282 A
  • Filed: 07/15/1974
  • Issued: 05/04/1976
  • Est. Priority Date: 07/15/1974
  • Status: Expired due to Term
First Claim
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1. In a rider-driven vehicle having a frame and at least one driven wheel journalled in the frame for rotation with respect thereto, a variable speed drive mechanism of the type that includesa rotatable driving member mounted for rotation with respect to the frame and having a first predetermined effective circumference;

  • unidirectional torque transmitting means connected between the driving member and the driven wheel for transmitting torque in only one direction from the driving member to the driven wheel;

    an elongated lever arm;

    means near one end of the lever arm for receiving a driving force exerted by a rider of the vehicle;

    means attached to the lever arm near its other end for connecting the lever arm to the vehicle frame to permit oscillatory movement of the lever arm about its other end within a predetermined angular sector with respect to the frame in response to the driving force exerted by the rider;

    anchor means mounted at one of a first attachment point connected to the lever arm intermediate the ends thereof and a second attachment point connected to the frame and lying approximately in the plane of oscillation of the lever arm and spaced to one side of the predetermined sector of oscillation;

    a rotatable intermediate member mounted at the other of said first and second attachment points, the intermediate member having a predetermined effect circumference;

    means for selectively changing the location of the second attachment point relative to the first attachment point for a given angular position of the lever arm so as to vary the angle between the lever arm and a line from the first to the second attachment point for the given angular position of the lever arm between predetermined limits, andmeans connecting the anchor means to the rotatable driving member by way of the rotatable intermediate member for transforming a tensile force acting on the anchor means along a line from the anchor means tangent to the effective circumference of the rotatable intermediate member, in response to the driving force exerted by the rider on the force receiving means, into a force acting on the driving member tangent to its effective circumference, wherein the improvement comprises;

    an arm pivotally attached at one end to a predetermined point on the lever arm intermediate the ends of the lever arm and having the first attachment point located at its other end anda drag link having one end pivotally attached to the arm at a point spaced from the one end of the arm, the drag link extending approximately parallel to the lever arm and having its other end pivotally connected to the frame between the oscillatory axis of the lever arm and the nearest one of the predetermined limits of the means for selectively changing the location of the second attachment point so that the first attachment point describes an arc approximately centered at the location of said predetermined limit in response to oscillation of the lever arm within the predetermined angular sector, whereby the distance between the first and second attachment points remains substantially constant for all positions of the lever arm within said angular sector when the second attachment point is located at said limit position.

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