Shaft ratchet release and sealing mechanism
A torque wrench having a handle and an output shaft is disclosed. The output shaft may be constrained to turn only unidirectionally due to a ratchet. Rotation of the output shaft may be permanently disabled by an internal mechanism. Torque imposed on the output shaft may be limited by a torque responsive cam clutch. The handle forms or is part of an enclosure enclosing internal components such as the ratchet, the internal disablement mechanism, and the torque responsive cam clutch. A seal between the body and the output shaft prevents ingress and egress of lubricants and contamination between the inside of the body and the output shaft.
1. A torque wrench having a feature for permanently discontinuing ability to transmit torque, comprising:
a handle;
an output shaft coupled to, and driven by rotation of, the handle, the output shaft having an axis of rotation about which the output shaft rotates when the handle rotates;
a torque control responsive to torques imposed on the output shaft from the handle, wherein the torque control comprises a torque responsive clutch which automatically disengages the output shaft from the handle upon attainment of a predetermined torque, wherein the torque responsive clutch is contained entirely within the handle, wherein the torque responsive clutch comprises opposed cams, wherein
the opposed cams interfit with one another in a torque transmitting mode when transmitting torque and
the opposed cams separate from one another in a released mode when not transmitting torque, and
a first spring urging the opposed cams towards one another;
a unidirectional ratchet selectively enabling the output shaft to rotate relative to the handle in a first direction when the handle is turned in the first direction about the axis of rotation and constraining the output shaft against rotating relative to the handle when the handle is turned in a second direction about the axis of rotation opposite the first direction, wherein the unidirectional ratchet is supported on and at least partially contained within the rotational coupling, wherein the unidirectional ratchet
has teeth projecting radially outwardly relative to the axis of rotation;
the teeth of the unidirectional ratchet engage corresponding grooves in the rotational coupling;
a push rod operable to advance along the rotational axis within the handle, contact the unidirectional ratchet, and displace the unidirectional ratchet axially out of engagement with the rotational coupling, wherein the push rod has threading, wherein said handle includes a threaded inhibiting member matingly compatible with the threading of the push rod, wherein the push rod is initially threaded to the threaded inhibiting member of the handle, and progressively unthreads from the threaded inhibiting member with each usage of the torque wrench;
a second spring urging the push rod towards the unidirectional ratchet, whereby when the push rod is fully unthreaded from the threaded inhibiting member, the second spring urges the push rod against the unidirectional ratchet such that the unidirectional ratchet is disengaged from the rotational coupling by displacing the teeth of the unidirectional ratchet axially out of engagement with the grooves of the rotational coupling; and
a disengagement feature which becomes operable to permanently disconnect the handle from the output shaft, wherein the disengagement feature displaces the teeth of the unidirectional ratchet axially out of engagement with the corresponding grooves of the rotational coupling, thereby enabling the output shaft to rotate freely relative to the handle.