US Patent 7251129 Two-way auto-locking tablet PC hinge

A two-way auto-locking tablet PC hinge is described. The two-way auto-locking tablet PC hinge includes a hinge base, a central rotational frame, a shaft, a fixing bracket, a rotational cam, a fixed cam, and two positioners. The fixing bracket, the rotational cam, and the fixed cam are configured on the shaft. A monitor of the tablet PC is fixed on the fixing bracket and the hinge base is fixed on a tablet PC base. The positioners are composed of protrusion blocks and concaves and are axially symmetrically formed on the fixed cam and the rotational cam respectively. When the monitor is parallel to the tablet PC base, the protrusion blocks are engaged with the concaves correspondingly, thereby locking the monitor on the tablet PC.