Patent ID: 8047738

Claim:
A mechanical joint system, comprising: a first joint member defining a pivot hole extending through a first flange portion and a second flange portion in perpendicular communication with a receiving slot that extends between the first and second flange portions; the second flange portion defining a plurality of locking grooves; an arm being rotatable relative to the first joint member and having a pivot portion pivotably received within the receiving slot of the first joint member, the pivot portion defining a pivot hole extending therethrough and being axially aligned with the pivot hole of the first joint member, the pivot hole of the pivot portion having a plurality of teeth formed on an inner surface adjacent to an end of the pivot hole of the pivot portion and a plurality of shaft positioning prong grooves defined in the inner surface adjacent to another end of the pivot hole of the pivot portion; and an engaging member received through the aligned pivot holes of the first joint member and the pivot portion of the arm, the engaging member comprising: a pivot shaft inserted in the pivot hole of the first joint member from an end thereof, and comprising a shaft head and a shaft portion extending from an end of the shaft head; the shaft portion defining a plurality of axial slots therein along a direction parallel to an axis of the shaft portion; and a pivot shaft positioner inserted in the pivot hole of the first joint member from an opposite end thereof, and the pivot shaft positioner comprising a shaft head and a plurality of latching rims extending from an end of the shaft head to engage in the locking grooves of the first joint member, the shaft positioning prong grooves, and finally engage into the axial slots of the pivot shaft correspondingly; wherein, each latching rim has a prong latching with one of the plurality of teeth of the arm, when an external force is applied to the arm, the plurality of teeth press the prongs into the axial slots to allow the arm to rotate relative to the first joint member.