Tri-cam axial extension to provide gripping tool with improved operational range and capacity

1. An improvement in a gripping tool having a gripping assembly with a grip surface carried by movable grip elements to radially move the grip surface from a retracted to an extended position, the gripping assembly being activated by axial movement, the improvement comprising:

a tri-cam linkage comprising a drive cam body, a driven cam body and at least one intermediate cam body, the drive cam body and the at least one intermediate cam body providing a drive cam pair with a cam surface on the drive cam body engaging a first cam surface on the at least one intermediate cam body, the at least one intermediate cam body and the driven cam body providing a driven cam pair with a second cam surface on the at least one intermediate cam body acting in opposition to the first cam surface and engaging a cam surface on the driven cam body, the tri-cam linkage acting between a body of the gripping tool and the gripping assembly translating bi-rotary movement in either a clockwise or counterclockwise direction of the body relative to the grip surface into axial movement to drive axial stroke activation of the gripping assembly.

2. An improvement in a gripping tool having a gripping assembly with a grip surface carried by movable grip elements to radially move the grip surface from a retracted to an extended position, the gripping assembly being activated by axial movement, the improvement comprising:

a tri-cam linkage comprising a drive cam body, a driven cam body and at least one intermediate cam body, the drive cam body and the at least one intermediate cam body providing a drive cam pair with a cam surface on the drive cam body engaging a first cam surface on the at least one intermediate cam body, the at least one intermediate cam body and the driven cam body providing a driven cam pair with a second cam surface on the at least one intermediate cam body acting in opposition to the first cam surface and engaging a cam surface on the driven cam body, the tri-cam linkage acting between a body of the gripping tool and the gripping assembly translating bi-rotary movement in either a clockwise or counterclockwise direction of the body relative to the grip surface into axial movement to drive axial stroke activation of the gripping assembly;

wherein the drive cam pair is arranged to only be active to cause axial stroke as a function of rotation under a first direction of rotation and the driven cam pair under the second direction of rotation, which separation of bi-rotary activation into two cam pairs facilitates providing greater axial stroke and correlatively radial stroke of the grip surface than is possible where a single cam pair is employed in a bi-rotary activated linkage.

3. The improvement of claim 1 , wherein the tri-cam linkage is arranged with a latch that when engaged will prevent axial stroke activation of the tri-cam linkage.

4. The improvement of claim 3 , wherein the tri-cam linkage is provided with a mechanical lockout comprising a lockout dog on one portion of the latch and a mating lockout dog pocket on another portion of the latch that when activated prevent engagement of the latch.

5. A gripping tool, comprising:

at least one body including an associated load adaptor adapted to be connected to and interact with one of a drive head or reaction frame;

a gripping assembly carried by the at least one body and having at least one grip surface adapted to move from a retracted position to an engaged position to radially engage the grip surface with a work piece upon relative axial displacement of the at least one body relative to the grip surface in at least one axial direction; and

a tri-cam linkage acting between the at least one body and the gripping assembly, the tri-cam linkage comprising a drive cam body, a driven cam body and at least one intermediate cam body, the drive cam body and the at least one intermediate cam body providing a drive cam pair with a cam surface on the drive cam body engaging a first cam surface on the at least one intermediate cam body, the at least one intermediate cam body and the driven cam body providing a driven cam pair with a second cam surface on the at least one intermediate cam body acting in opposition to the first cam surface and engaging a cam surface on the driven cam body, the tri-cam linkage translating bi-rotary movement in either a clockwise or counterclockwise direction of the load adaptor relative to the grip surface into axial movement to drive axial stroke activation of the gripping assembly.