Abstract: A torque wrench having an elongated hinge terminating in a ratchet ring with interiorally directed teeth has a work head for turning a workpiece and a pawl for selectively rotating the workpiece with rotational movement of the hinge. The pawl is provided with a lip directed radially outward from the axis of rotation of the work head. A corresponding annular groove is defined in the interior wall of the ratchet ring to receive the lip. Tilting or misalignment of the pawl within the cavity defined within the ratchet ring is thereby prevented. In its preferred embodiment, the pawl is equipped with a plurality of ratchet teeth with the lip extending outwardly from the generally convex surface into which the teeth are formed midway between the longitudinal extremities of the pawl perpendicular to the plane of the ratchet ring. The corresponding annular groove in the ratchet ring likewise divides the ratchet teeth into separate portions on either side of the pawl lip.

Abstract: A torque wrench is provided with a unique interconnection between the hinge, pivot and plunger. Both the hinge and plunger are channeled entirely across the width of their interfaces with the pivot normal to the plane of application of torque. A pivot retainer is provided to laterally constrain movement of the pivot. The pivot retainer may take the form of a flat disk with a rectangular aperture centrally located therein, it may be embodied in restraining pins extending transversely across the channel in the plunger face or it may include an axial guide rod extending through the plunger to engage and restrain the pivot.

Abstract: A ratchet is provided in which a friction brake ring is employed to engage a pawl with the ratchet teeth in an annular ring or hinge extending from a ratchet tool handle. The friction brake ring carries the pawl into engagement when the tool handle is rotated in the direction in which it is desired to turn a workpiece. A spring within the ratchet returns the pawl to a position in which it is disengaged entirely when pressure on the tool handle in the rotational direction of engagement is released. Thus, the return of the tool handle before a subsequent engaging stroke is accomplished silently and without the characteristic clicking of the ratchet teeth of the hinge passing over the pawl.

Abstract: A ratchet is provided in which directional indexing is achieved by rotation of an indexing member in the rotational direction in which it is desired to rotate a workpiece. Locking in an indexing position is achieved by means of detent mechanisms situated in a channel extending through a guide element and biased radially outward therefrom to interact with said indexing member. A pawl is provided within a cavity defined between a guide element extending from a torque transmitting member and an encircling annular ring at the end of the work handle. One surface of the pawl is of arcuate configuration equipped with ratchet teeth engageable with corresponding ratchet teeth on the interior surface of the annular ring of the work handle. An opposing surface of the pawl is of overall convex configuration so that the pawl may be rolled across a planar bearing surface of the guide element under the influence of the directional indexing member.

Abstract: An electronic torque wrench including a strain measuring bridge circuit disposed to measure the bending strain of the handle thereof, a NAND gate circuit connected to alternately excite the bridge according to the switching state thereof, a differential circuit connected to receive the bridge balance signal, an integrator connected to integrate a selected polarity output signal from said differential circuit, a clock-driven counter connected to be inhibited for a predetermined time interval following each time the integrating circuit output signal changes polarity providing selected binary level output signals to switch the NAND gate circuit according to the state thereof and a logical switching circuit connected to the selected binary level output signals of said counter for alternatively connecting either the output signal from the differential circuit or a fixed reference signal to the integrator.