192 clutches and power-stop control – Clutches – Automatic
Reexamination Certificate
1999-08-20
2001-02-20
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Automatic
C192S071000
Reexamination Certificate
active
06189666
ABSTRACT:
This invention relates to a ratchet mechanism for enabling motion to be transmitted in one direction but not in the opposite direction. Such mechanisms are also referred to as mechanical diodes, one way clutches and the like. The term ratchet mechanism used herein is intended to embrace such mechanisms.
Conventional ratchet mechanisms generally comprise a plurality of pawls which are spring biased radially outwardly by springs so that during rotation in one direction the pawls engage teeth to lock the mechanism and when rotated in the opposite direction, the pawls run over the teeth to allow free rotation. Whilst these mechanisms do operate adequately, they are expensive, relatively complicated to manufacture and particularly difficult to repair in some environments, particularly when used in yacht winches and, if repair is necessary, whilst the yacht is racing.
The object of this invention is to provide a ratchet mechanism which overcomes these problems.
The invention may be said to reside in a ratchet mechanism, including:
an inner member;
an outer member;
at least one tooth on one of the inner or outer member;
an engagement member on the other of the inner or outer member, the engagement member being mounted on the said other of the inner or outer member for movement relative to the said other of the inner or outer member;
an engagement tooth on the engagement member; and
a drive portion on the engagement member for contact by said one of the inner or outer member for moving the engagement member into position whereby the engagement tooth engages the said at least one tooth.
The ratchet mechanism of this invention need not include springs and therefore it is not necessary to locate a small spring and pawl mechanism when maintaining or repairing the ratchet mechanism. The ratchet mechanism merely requires the insertion of the engaging member in position and since this can take place without the need to locate a spring, repair and assembly is much simpler than in conventional ratchet mechanism.
Preferably the said one of the inner or outer member has a plurality of teeth, said at least one tooth being at least one of the plurality of teeth, and one of the plurality of teeth contacts the engagement member to move the engagement member so that the engagement tooth engages the at least one tooth of the plurality of teeth.
Preferably the drive portion comprises a surface of the engagement member and contact between the said one of the inner or outer member and the surface of the engagement member causes the engagement member to rock relative to the other of the inner or outer member to bring the engagement tooth of the engagement member into position whereby the engagement tooth can engage with said at least one tooth of the said one of the inner or outer member.
The surface of the engaging member providing the drive portion may be a bump on the engagement member or may be a smooth continuous portion of the surface of the engagement member.
The invention may also be said to reside in a ratchet mechanism including:
an outer ring having at least one tooth on an inner circumference thereof;
an engaging member having at least one tooth for engaging the at least one tooth of the outer ring, the engaging member being arranged within the outer ring;
a drive member for moving the engaging member into engagement with the outer ring; and
a shaft for supporting the drive member; wherein
upon rotation of the shaft in one direction, the drive member is rotated to force the at least one tooth of the engaging member into engagement with the at least one tooth of the outer ring so that the shaft, engaging member and outer ring move as a single unitary body and upon rotation of the shaft in an opposite direction, the drive member moves the engaging member so the at least one tooth of the engaging member moves out of engagement with the at least one tooth on the outer ring so that the shaft can rotate freely relative to the outer ring.
In one embodiment, the engaging member comprises an engaging ring having a plurality of teeth on part only of its outer circumference.
In one embodiment of the invention, the drive member comprises a surface portion on the engaging ring and a cam member on the inner ring which engages in a recess in the engaging ring so that when the inner ring is rotated in said one direction, the engaging ring is rotated in the same direction by engagement of the cam in the recess and the driving surface on the ring contacts the outer ring so as to lift the engaging ring to place the teeth of the engaging ring into engagement with the at least one tooth of the outer ring.
In another embodiment, the engaging member comprises a plurality of segments arranged about the inner periphery of the outer ring, each segment having at least one tooth for engaging at least one tooth of the outer ring upon rotation of the shaft in said one direction.
In one embodiment the drive member comprises a cam disc having a cam which is fixed on the shaft and the inner ring or segment has a recess portion for receiving the cam so that upon rotation of the shaft in the first direction, the cam engages the ring or segment to force the at least one tooth of the inner ring or segment into engagement with the at least one tooth of the outer ring.
Preferably the cam includes shoulders for engaging corresponding shoulders on the inner ring or segment so that upon rotation of the shaft the shoulders on the cam abut the shoulder on the inner ring or segments to move the teeth into and out of engagement.
In another embodiment the segments have elongate slots and the cams are cylindrical projections which are received in the slots.
In one embodiment of the invention the segments are rectangular block shaped and the at least one tooth of the segment is formed by a corner apex of the block shaped segment.
In another embodiment of the invention, the engaging member is carried shaft and the drive member is a projection provided on the engaging member so that upon rotation in one direction, the at least one tooth of the outer ring engages the projection and moves the tooth of the engaging member out of engagement with the at least one tooth of the outer ring and, upon rotation in the opposite direction, the projection engages the at least one tooth of the outer ring to cause the tooth of the engaging member to engage with the at least one tooth of the outer ring so that drive is transmitted from the outer ring via the engaging member to the shaft.
In one embodiment of the invention, the inner ring is arranged generally concentrically with the outer ring. However, in an alternative embodiment, the inner ring is arranged eccentrically with respect to the outer ring.
The invention in a further aspect may be said to reside in a ratchet mechanism, including:
an outer member having a plurality of teeth on an inner circumferential surface;
an inner member having a retaining portion;
an engaging member mounted for rocking movement on the retaining portion of the inner member;
at least one tooth on the engaging member;
a drive portion on the engaging member; and
wherein upon rotation of the outer ring in one direction, the teeth of the outer ring engage the drive portion of the engaging member to rock the engaging portion relative to the retaining member so that the at least one tooth of the engaging portion is disengaged from the teeth of the outer member to allow the outer member and inner member to rotate relative to one another, and upon rotation in the opposite direction, the teeth of the outer member engage the drive portion to rock the engaging member so as to cause the at least one tooth of the engaging portion to engage with at least one of the teeth of the outer ring so that the drive is transmitted from the outer ring via the engaging member to the inner member.
Preferably the retaining portion comprises an arcuate groove in the inner member and an arcuate scallop adjacent the groove which define a retaining boss on the inner member.
Preferably the engaging member has a retaining recess for engaging the retaining bos
Aimbridge Pty Ltd
Bonck Rodney H.
Michael & Best & Friedrich LLP
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