Patent ID: 7260975

Claim:
A method of designing and modifying a compression tool jawset to displace a jawset and spring pin from an operative position thereof upon failure of a jawarm of the jawset at the spring pin location, the jawset comprising a pair of side plates, a pair of jawarms having pivot pin openings receiving pivot pins between said plates, each jawarm having inner and outer edges laterally spaced from and extending forwardly and rearwardly of the corresponding pivot pin opening, said inner edges including laterally inwardly open opposed jaw recesses forwardly of the pivot pin openings and inwardly facing cam surfaces rearwardly of the openings, the jawarms during use of the compression tool being pivotal about the pivot pins in response to forces laterally outwardly against the cam surfaces to displace the jaw recesses laterally inwardly in a closing direction to compress an object therebetween, whereby an area of each jawarm between the corresponding pivot pin opening and inner edge thereof and between the cam surface and jaw recess thereof is under tension, a spring pin opening defined by opposed pin recesses, each in said area of the corresponding jawarm, said pin recesses having opposed front ends and opposed rear ends, a spring pin in said opening and having a given length and a given diameter, and a spring having a forward end extending across said pin and legs extending rearwardly each along the inner edge of a different one of the jawarms, said spring pin opening supporting said spring pin in an operative position and said spring biasing said jaw recesses in the closing direction, said method comprising: (a) analyzing at least one of the jawarms to determine that the stress at the pin recess thereof will result in a fatigue crack initiated at the pin recess during use and fracture of the jawarm from the fatigue crack to a point spaced therefrom toward the outer edge of the jawarm, (b) determining the amount of acceptable deformation of the jawarm along the fracture when the fracture reaches said point, and (c) modifying at least one of the spring pin opening and the spring pin in said jawset for the spring to displace the spring pin from the operative position thereof when said acceptable amount of deformation is reached.