Patent ID: 7100479

Claim:
Self-adjusting pliers having upper and lower jaws for grasping a workpiece and upper and lower arms for grasping by the hand of a user, comprising: the upper arm having a first end and a second end, wherein the upper jaw is at the first end of the upper arm; a jaw arm having a first end and a second end, wherein the second end of the jaw arm is pivotably connected to the upper arm at a main pivot adjacent to the second end of the upper arm, so that the first end of the jaw arm is movable in a circular arc relative to the main pivot, and wherein the lower jaw is at the first end of the jaw arm in movable facing relation to the upper jaw so that the workpiece may be grasped between the upper jaw and the lower jaw; the lower arm linked to the jaw arm at a location adjacent the lower jaw but not integral with the jaw arm; an engagement mechanism that, upon the user's squeezing together of the upper arm and the lower arm, releasably engages the jaw arm, lower jaw and the lower arm to the upper arm and the upper jaw, said engagement mechanism being responsive to a movement of the jaw arm relative to the upper arm and to a size of the workpiece grasped between the upper jaw and the lower jaw; and a support integral with and extending from the upper arm toward and past the jaw arm, the support including a support engagement curved in a circular arc centered about the main pivot, a control arm having a first end and a second end, wherein the first end of the control arm is pivotably connected to the jaw arm at an upper control-arm pivot pin adjacent to the second end of the jaw arm, and wherein the second end of the control arm is pivotably connected to the lower arm at a lower control-arm pivot point at a location along the length of the lower arm, and a lower-arm spring biasing the lower arm so as to resist rotation of the lower arm about the upper control-arm pivot pin.