Snap-on Tools Corporation

American Pneumatic Technologies, Inc.

Timm R Herman

Jeffrey R Annis

Ronald T Strobel

Frank Mikic

Donald J Caldwell

Mark S Bakula

Andrzej J Dlugolecki

Allan J Bliemeister

Eric T Gustafson

A torque wrench has a battery-powered sensing circuit which produces a torque signal proportional to the level of the torque applied. A reference signal corresponding to a predetermined torque level is subtracted from the torque signal to produce a difference signal which is, in turn, compared with a compensation signal which is proportional to the rate of change of the torque signal and is produced by differentiating the torque signal. When the value of the difference signal exceeds the value of the compensation signal, an indicator is triggered to produce a tactile indication, the indication being produced prior to the time that the torque signal reaches the reference level by a predetermined time period.

Electronic torque wrench and overshoot compensation circuit therefor

An electronic torque wrench has a hollow handle portion in which are disposed a DC motor mechanically coupled to the handle portion with a mass eccentrically mounted on its shaft, a control circuit for the motor and a battery for powering the motor and the control circuit. A strain sensor on the wrench produces an output signal when the torque applied to a workpiece equals or exceeds a predetermined torque level for causing the control circuit to actuate the motor to vibrate the handle portion and provide a tactile indication to the user.

Electronic torque wrench with tactile indication

A self-locking pliers provides automatic jaw adjustment for gripping objects of different sizes. First and second pinsers-defining members each have a body portion, a jaw-defining portion and a handle portion, being joined by a bolt extending through a slot in one of the members in pivotal, mutually moveable relationship. The slot permits pivoting as well as sliding movement of the first member relative to the second member, and has along a jaw-proximate side teeth to be engaged by corresponding teeth of a locking pawl carried rotatably within the slot by a shank of the bolt. A jaw-remote side of the slotted opening provides a smooth surface for sliding engagement of a smooth reaction surface of the locking pawl opposite from its teeth. The locking pawl has on its jaw-proximate side a camming surface proximate to the locking teeth. A control arm is pivotally engaged at one end to the body portion of the second member. The body portion of the first member receives the other end of the control arm in slidably captive relationship, while a spring carried by the second member resiliently biases the control arm for movement about its pivoted end toward the jaws. The control arm initially causes the locking pawl reaction surface to bear against the jaw-remote side of the slot, so that squeezing the handles causes jaw-closing movement of the jaws until they close upon an object until contacted by the jaws. Such jaw contact the jaws causes the pawl to rotate within the slot for forcing its teeth into locking engagement with the rack for maintaining the jaws in locked, object-contacting relationship while handle pressure is maintained by the user. An interference-providing arrangement including a detent for the control arm provides controlled pawl engagement of the toothed rack and avoids 'hanging up' the pawl or its inadvertent engagement.

Adjustable pliers

The ratcheting screwdriver comprises a handle having a bore and a keyway substantially tangent thereto. In the bore is a gear and in the keyway are a pair of pawls which are movable individually into and out of engagement with the gear. An actuator is provided at the forward end of the handle to move these pawls. A cap operates the actuator.

Ratcheting screwdriver

The mechanism, used in a ratchet wrench, includes a body carrying an integral stud. A bore extends axially into both and a formed-spring actuator is reciprocally mounted therein. A transverse bore in the stud slidably holds a pin which is connected to the actuator. A socket is applied to the mechanism by pushing the socket against a camming surface on the pin to enable the socket to be snapped onto the pin without operating the actuator. The socket is removed by depressing the actuator. A ramp-like structure in the bore engages an offset part of the formed-spring actuator causing it to divert and move the pin to its release position. An elastomer push button is preferably attached to the actuator to sealingly protect the mechanism and also to provide a nice appearance.

Growing community of inventors

Kenosha, WI, United States of America

Timm R Herman