Self-adjusting pliers
 A self-adjusting pliers has an upper arm with an upper jaw at a first end and an upper handle at a second end. A support extends downwardly from an intermediate location of the upper arm. The support has a first downwardly extending slot and a second downwardly extending slot that is parallel to the first downwardly extending slot and closer to the upper handle than the first downwardly extending slot. The second downwardly extending slot has a plurality of second-slot teeth on a side thereof adjacent to the first downwardly extending slot. A lower arm includes a first end, and a lower handle at a second end. A control arm is pivotably connected at a first end to the upper handle and at a second end to the lower arm at an intermediate location between the first end and the lower handle. A spring is affixed at a first end to the upper arm at a location adjacent to the first end thereof, and affixed at a second end to the control arm so as to resist rotation of the control arm. A lower jaw member includes a lower jaw at a first end and in a facing relationship to the upper jaw. A slider extends from a side of the lower jaw member and is slidably engaged to the first downwardly extending slot. A pawl is disposed within the second downwardly extending slot and has a set of pawl teeth in facing relationship to the second slot teeth. A shifter has three pivot points arranged in a triangular pattern, the three pivot points being respectively connected to the lower jaw member, to the pawl, and to the first end of the lower arm. 
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inventional inventional
Eric B. Brett P.
Carmichael Seber