Patent ID: 7240441

Claim:
An excavator thumb assembly for use with an excavator having a boom, a hydraulic cylinder, a hydraulic cylinder shaft that extends and retracts from the hydraulic cylinder, a bucket, a bucket linkage arm, and a cam, where the bucket is pivotally attached to an end of the boom along a first pivot axis, a first end of the cam is pivotally attached to the boom along a second pivot axis, a first end of the bucket linkage arm is pivotally attached to the bucket along a third pivot axis, a second end of the bucket linkage arm is pivotally attached to a second end of the cam along a fourth pivot axis, and the hydraulic cylinder shaft is pivotally attached to the second end of the cam along the fourth pivot axis, the excavator thumb assembly comprising: a thumb pivot plate attached to an intermediate portion of the boom and including a thumb attachment point positioned above the longitudinal axis of the boom; a thumb pivotally attached to the thumb attachment point along a fifth pivot axis, and including a thumb/actuator attachment point; and an actuator including: a first end pivotally attached to the thumb/actuator attachment point along a sixth pivot axis; and a second end that includes a cam/actuator attachment point pivotally attached to the cam along a seventh pivot axis; wherein the excavator thumb assembly is configured so that the thumb and bucket opposably grab and release objects as the hydraulic cylinder shaft extends and retracts, respectively.