Patent ID: 6988428

Claim:
A rotary gear, for use in a power tong having: (a) a gear housing defining a central space, and a perimeter opening into said space; and (b) a pair of opposing jaw members disposed within said central space, each jaw member having: b.1 a pivot end, a free end, an inner side, and an outer side, with said pivot end pivotably mounted to the gear housing, and said free end oriented toward said perimeter opening; b.2 a pair of dies associated with said inner side; and b.3 a cam follower associated with said outer side; said rotary gear being rotatably mountable within the gear housing, and having: (c) a circular perimeter with a plurality of gear teeth; (d) an inner surface defining a central space large enough to enclose said jaw members; and (e) a throat opening in said perimeter; wherein said inner surface defines: (f) a pair of opposed neutral recesses; and (g) a first pair of opposing primary camming surfaces, each extending substantially linearly in a first direction away from an associated one of the recesses; and wherein the radial distance from the axis of rotation of the rotary gear to a point on any primary camming surface decreases substantially linearly with increased distance from the associated recess.