improved , manually - operable , adjusting mechanisms for click - type , adjustable torque wrenches which include manually - engageable , resilient , plastic , tubular handgrips slidably engaged about the rear end portions of elongate , tubular , metal wrench lever arms and which are shiftable longitudinally from normal , forward positions in rotary - driving engagement with the arms to actuated rear positions out of rotary - driving engagement with the arm . the invention resides in an improved locking mechanism releaseably locking the grip in rotary - driving engagement with the arm when in its normal position and yieldingly permitting rotation of the grip relative to the arm when turning forces between the arm and grip exceed the shear strength of the material of which the grip is made . the locking means include a plurality of circumferentially - spaced , inside flats about the exterior of the arm and a plurality of circumferentially - spaced , outside flats about the interior of the grip normally establishing flat bearing and rotary - driving engagement with the inner flats when the grip is in its normal position . the adjacent inner flates define cam edges to engage the surfaces of the outside flats and to yieldingly expand the grip when forceably rotated relative to the arm .