Patent ID: 8333527

Claim:
A mechanical joint system, comprising: a joint defining a pivot hole, a joint receiving hole communicating with the pivot hole, and a plurality of locking grooves communicating with the pivot hole; an arm being rotatable relative to the joint, the arm comprising a pivot portion and a pivot hole defined in the pivot portion, the pivot portion being received in the joint receiving hole; a plurality of teeth formed on an inner surface adjacent to an end of the pivot hole of the arm; and an engaging member comprising a pivot shaft, a fixing member, and at least one prong, the pivot shaft being fixed to the joint and comprising a shaft head, a shaft portion extending from an end of the shaft head, and a plurality of latching rims locked in the plurality of locking grooves circling an end of the shaft portion and connected to an end of the shaft head, the shaft head being inserted into the pivot hole of the arm from an end thereof, the fixing member being inserted into the pivot hole of the arm from an opposite end thereof, and fixed relative to the pivot shaft; wherein the shaft portion defines a threaded hole in an end opposite to the shaft head and at least one groove communicating with the threaded hole thereby forming an elastic plate connecting to the shaft portion, and the prong extends from an outer surface of the elastic plate for engaging with the teeth.