Shaft ratchet release and sealing mechanism

Abstract

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.

I claim: 
     
         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; and   a disengagement feature which becomes operable to permanently disconnect the handle from the output shaft.   
     
     
         2 . The torque wrench of  claim 1 , wherein the torque control comprises a torque responsive clutch which automatically disengages the output shaft from the handle upon attainment of a predetermined torque. 
     
     
         3 . The torque wrench of  claim 2 , wherein the torque responsive clutch is contained entirely within the handle. 
     
     
         4 . The torque wrench of  claim 3 , 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 spring urging the opposed cams towards one another.   
     
     
         5 . The torque wrench of  claim 1 , wherein the disengagement feature comprises a rotational coupling between the handle and the output shaft, the rotational coupling contained entirely within the handle. 
     
     
         6 . The torque wrench of  claim 4 , further comprising 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.   
     
     
         7 . The torque wrench of  claim 6 , wherein the unidirectional ratchet is supported on and at least partially contained within the rotational coupling. 
     
     
         8 . The torque wrench of  claim 7 , 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; and   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.   
     
     
         9 . The torque wrench of  claim 8 , further comprising 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. 
     
     
         10 . The torque wrench of  claim 9 , wherein
 the push rod has threading,   the handle comprises a threaded inhibiting member matingly compatible with the threading of the push rod,   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;   the torque wrench comprises 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. 
   
     
     
         11 . The torque wrench of  claim 1 , wherein the handle forms an enclosure from which the output shaft projects, the torque wrench further comprising a seal between the output shaft and the handle. 
     
     
         12 . The torque wrench of  claim 11 , wherein the seal comprises a first resilient layer and a second resilient layer each spaced apart from one another along the axis of rotation. 
     
     
         13 . A torque wrench having a unidirectional output regardless of direction of rotation of the torque wrench, 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; and   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.   
     
     
         14 . The torque wrench of  claim 13 , 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; and   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.   
     
     
         15 . The torque wrench of  claim 13 , wherein the torque control comprises a torque responsive clutch which automatically disengages the output shaft from the handle upon attainment of a predetermined torque. 
     
     
         16 . The torque wrench of  claim 15 , wherein the torque responsive clutch is contained entirely within the handle. 
     
     
         17 . The torque wrench of  claim 16 , 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 spring urging the opposed cams towards one another.   
     
     
         18 . The torque wrench of  claim 13 , wherein the handle forms an enclosure from which the output shaft projects, the torque wrench further comprising a seal between the output shaft and the handle. 
     
     
         19 . The torque wrench of  claim 18 , wherein the seal comprises a first resilient layer and a second resilient layer each spaced apart from one another along the axis of rotation. 
     
     
         20 . The torque wrench of  claim 13 , wherein the torque control and the unidirectional ratchet are contained entirely within the handle.