Compression tool jawarm member
AssigneeEmerson Electric Co.
InventorsJames E. Hamm, James E. Smolik, Jason M. Smith
Life of this patent
Estimating the term…
Abstract
A pivotal jawarm for a compression tool has opposite sides, a pivot pin opening therethrough, longitudinally opposite ends on longitudinally opposite sides of the opening, and inner and outer edges between the ends and on laterally opposite sides of the opening. A stress concentrator comprising aligned recesses in the opposite sides of the jawarm extends from the inner edge toward the pivot pin opening and provides a failure point at the inner edge for consistently initiating a fatigue crack at the failure point and fracture of the jawarm from the failure point to the pivot pin opening.
Claims83
A jawarm for a compression tool, said jawarm having opposite sides, an opening therethrough, longitudinally opposite ends on longitudinally opposite sides of said opening, inner and outer edges between said ends and on laterally opposite sides of said opening, and a stress concentrator in said jawarm along said inner edge and providing a failure point at said inner edge for consistently initiating a fatigue crack at said failure point and fracture of said jawarm from said failure point toward said opening.
A pivotal jawarm for a compression tool, said jawarm having opposite sides, an opening therethrough, longitudinally opposite ends on longitudinally opposite sides of said opening, inner and outer edges between said ends and on laterally opposite sides of said opening, and a stress concentrator in said jawarm between said inner edge and said opening and providing a failure point at said inner edge for consistently initiating a fatigue crack at said failure point and fracture of said jawarm from said failure point to said opening.
A compression tool comprising, a pair of parallel spaced apart side plates having front and rear ends and laterally opposite sides, aligned holes through said plates at each of said opposite sides, a pair of jawarms between said plates, each said jawarm having an opening therethrough aligned with the holes through a different one of said opposite sides, each said jawarm being pivotally mounted between said plates by a pin extending through the opening therethrough and the corresponding aligned holes through said side plates, each said jawarm having inner and outer edges laterally spaced from the opening therethrough and extending forwardly and rearwardly of the opening therethrough, said inner edges providing laterally inwardly open opposed jaw recesses forwardly of said front ends of said side plates and laterally inwardly facing cam surfaces rearwardly of said rear ends of said side plates, the jawarms during use of the compression tool being pivoted about said pins in response to forces laterally outwardly against said cam surfaces to displace said jaw recesses laterally inwardly to compress an object therebetween, whereby an area of each jawarm between the opening and inner edge thereof and between the cam surface and jaw recess thereof is under tension, and a stress concentrator in said area of each jawarm for consistently initiating a fatigue crack at a failure point along the inner edge thereof and fracture of the jaw member from said failure point to the opening therethrough.
A method of controlling failure of a pivotal jawarm for a compression tool comprising, producing a jawarm having opposite sides, an opening therethrough, longitudinally opposite ends on longitudinally opposite sides of said opening, and inner and outer edges between said ends and on laterally opposite sides of said opening, reducing the amount of material in an area of said jawarm between said inner and outer edges to produce a failure point at said inner edge for consistently initiating a fatigue crack at said failure point and fracture of said jawarm from said failure point toward said opening.
A method of designing a compression tool jawarm to have a stress concentrator for controlling failure of the jawarm, comprising designing a jawarm profile having opposite sides, an opening therethrough, longitudinally opposite ends on longitudinally opposite sides of said opening, and inner and outer edges between said ends and on laterally opposite sides of said opening, choosing a jawarm life in cycles of operation, choosing a steel for the jawarm, selecting a heat treating process for the jawarm, selecting a maximum stress level for failure of the jaw arm, selecting a location along the inner edge for the stress concentrator, designing the stress concentrator to provide a failure point at the inner edge for initiating a fatigue crack at the selected maximum stress and fracture of the jawarm from the failure point toward the opening, and sizing the remainder of the jawarm to have a stress level less than the selected maximum stress level.
Dependencies are inferred from the claim text.