Robust nose torque-limiting device
View Patent ↗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.
1. A method of reducing plastic nose cone breakage of a disposable torque-limiting driver operating at a selected torque, the method comprising:
applying a preselected amount of torque to a tool fitted to a torque limiting device via a drive socket of a plastic nose section;
said drive socket having been formed of four substantially planar walls and interposed between each wall is an arched corner catch each with a radius configured to distribute the force caused by turning a shaft at the predetermined torque without cracking the plastic nose cone over a predetermined number of rotations;
wherein the predetermined torque is at least 60 inch pounds;
wherein the nose cone continues to function within the predetermined torque range for at least about 105 cycles; and
wherein the radius is between 0.1266 inches and 0.1794 inches.
2. The method of claim 1 wherein the predetermined torque is between about 75 inch pounds and about 85 inch pounds.
3. The method of claim 2 wherein the nose cone continues to function within the predetermined torque range for at least about 108 cycles.
4. The method of claim 2 wherein the nose cone continues to function within the predetermined torque range for at least about 138 cycles.
5. The method of claim 1 the predetermined torque is between about 105 inch pounds and about 110 inch pounds.
6. The method of claim 5 wherein the nose cone continues to function within the predetermined torque range for at least about 135 cycles.
7. The method of claim 1 the predetermined torque is above about 120 inch pounds.
8. The method of claim 7 wherein the nose cone continues to function within the predetermined torque range for at least about 135 cycles.
9. The method of claim 1 , wherein the radius is between 0.1482 inches and 0.1638 inches.
10. The method of claim 1 , wherein the radius is between 0.1292304 inches and 0.1716 inches.