Reversible ratchet mechanism
OwnerDavid H. Vroominventor
Life of this patent
Estimating the term…
Abstract
A reversible ratchet mechanism includes a pair of roller clutches set to operate in opposite directions when engaged by a belt. During the forward motion of the ratchet assembly in either direction of propulsion of the belt, one roller clutch is disengaged while the other is engaged and locked, thereby propelling the belt. During the backward stroke, the engaged roller clutch is free to rotate. The result is that the reciprocating motion of the assembly is converted into the linear motion of the belt. The ratchet assembly includes a shift mechanism to reverse the engagement of the roller clutches and change the direction of propulsion of the belt produced by the push/pull action of the operator. The invention is advantageously used in conjunction with a wheelchair.
Claims19
A reversible ratchet mechanism for converting a reciprocating motion of an actuating force to an intermittent unidirectional motion of a ratch, comprising:
- a lever adapted for reciprocating motion in relation to a support structure;
- means for alternatively coupling the ratch to the lever under a first condition of operation wherein the ratch is engaged during a first stroke of said reciprocating motion and is disengaged during an opposite second stroke, or under a second condition of operation wherein the ratch is disengaged during the first stroke and engaged during the opposite second stroke of the reciprocating motion;
- and
- means for selectively shifting between said first and second conditions of operation, wherein said lever is pivotally mounted on a frame adapted for said reciprocating motion in relation to a support structure;
- said means for alternatively coupling the ratch to the lever includes two roller clutches mounted on the lever, one roller clutch being freely rotatable clockwise and becoming locked when urged to rotate counterclockwise and the other roller clutch being freely rotatable counterclockwise and becoming locked when urged to rotate clockwise;
- and said one roller clutch engages the ratch during the first condition of operation and said other roller clutch engages the ratch during the second condition of operation;
- and further including an idle roller rotatably mounted on said frame opposite to each of said roller clutches to support said ratch when the ratch is engaged by either of the roller clutches.
In a wheelchair, the improvement comprising:
- a carrier arm;
- a reversible ratchet mechanism mounted on the carrier arm for converting a reciprocating motion of an actuating force to an intermittent unidirectional motion of a ratch coupled to a propelling mechanism for a wheel of the wheelchair;
- a lever adapted for reciprocating motion in relation to the carrier arm;
- means for alternatively coupling the ratch to the lever under a first condition of operation wherein the ratch is engaged during a first stroke of said reciprocating motion and is disengaged during an opposite second stroke, or under a second condition of operation wherein the ratch is disengaged during the first stroke and engaged during the opposite second stroke of the reciprocating motion;
- and
- means for selectively shifting between said first and second conditions of operation;
- wherein said lever is pivotally mounted on a frame adapted for said reciprocating motion in relation to the carrier arm;
- said means for alternatively coupling the ratch to the lever includes two roller clutches mounted on the lever, one roller clutch being freely rotatable clockwise and becoming locked when urged to rotate counterclockwise and the other roller clutch being freely rotatable counterclockwise and becoming locked when urged to rotate clockwise;
- and said one roller clutch engages the ratch during the first condition of operation and said other roller clutch engages the ratch during the second condition of operation;
- and further including an idle roller rotatably mounted on said frame opposite to each of said roller clutches to support said ratch when the ratch is engaged by either of the roller clutches.
A reversible ratchet mechanism for converting a reciprocating motion of an actuating force to an intermittent unidirectional motion of a ratch, comprising:
- a lever adapted for reciprocating motion in relation to a support structure;
- means for alternatively coupling the ratch to the lever under a first condition of operation wherein the ratch is engaged during a first stroke of said reciprocating motion and is disengaged during an opposite second stroke, or under a second condition of operation wherein the ratch is disengaged during the first stroke and engaged during the opposite second stroke of the reciprocating motion;
- and
- means for selectively shifting between said first and second conditions of operation, wherein said lever is pivotally mounted on a frame adapted for said reciprocating motion in relation to a support structure;
- said means for alternatively coupling the ratch to the lever includes two roller clutches mounted on the lever, one roller clutch being freely rotatable clockwise and becoming locked when urged to rotate counterclockwise and the other roller clutch being freely rotatable counterclockwise and becoming locked when urged to rotate clockwise;
- and said one roller clutch engages the ratch during the first condition of operation and said other roller clutch engages the ratch during the second condition of operation, and wherein said means for selectively shifting between said first and second conditions of operation includes a fulcrum between said roller clutches;
- a travel slot and a fixed pin engaged by the travel slot to limit a range of motion of the lever between said first and second conditions of operation;
- and a retaining notch and a spring-loaded mechanism adapted to releasably engage the lever at each position corresponding to said first and second conditions of operation.
Dependencies are inferred from the claim text.