Robust Nose Torque-Limiting Device

摘要

A torque-limiting driver has a handle, a body, a torque-limiting assembly and a work-piece engaging tip. The torque-limiting assembly includes an upper and lower shank that have a plurality of teeth circumferentially spaced. The teeth have a vertical face, an inclined face, and a flat peak. There is a spring for applying pressure across the upper and lower shank with multiple washers interposed between the lower shaft and spring. In some instances, there is a round square drive with arched catches having preselected radii to assure operation over certain cycles at selected torque and to reduced nose cone damage and breakage at a predetermined inch pounds of torque.

主权项

1. A disposable torque-limiting driver comprising:
a handle and an axially extending cylindrical body; and a torque-limiting assembly within the axially extending cylindrical body, the assembly comprising:
an upper cylindrical shank;a lower cylindrical shank;wherein the upper cylindrical shank and the lower cylindrical shank have a plurality of teeth and an axial bore, the teeth have a vertical face, an inclined face and a substantially flat peak, wherein the inclined face is defined by a first radius of curvature that transitions to the substantially flat peak and wherein the teeth spiral around the axial bore;a spring for applying pressure across the upper cylindrical shank and the lower cylindrical shank, wherein the teeth of the upper cylindrical shank and the lower cylindrical shank engage for relative rotation, and wherein the teeth disengage when a predetermined value of torque is exceeded;a locking screw inserted through said spring and threaded to mate with the lower cylindrical shank through the upper cylindrical shank;a plurality of bearing surfaces formed between two washers interposed between the distal end of said spring and the upper cylindrical shank, wherein the two washers form one bearing surface when moving together, and wherein when the spring interferes with movement of one washer the bearing surface is between the washers; anda plastic nose cone at the distal end of the lower shaft with a drive socket in the nose cone.