Patent ID: 7971863

Claim:
A clamping apparatus, comprising: a supporting body; a plurality of clamping units installed on the supporting body, each clamping unit including a magnet, a clamping pin, an electrical coil, and a coil core, the magnet being configured for holding the clamping pin at a target position, the clamping pin being mechanically engaged with the coil core; a PWM controller configured for supplying a pulse signal to the electrical coil of each clamping unit and for thereby creating a magnetic force, the magnetic force causing a corresponding coil core and a corresponding clamping pin to, synchronously, selectably move toward or away from the electrical coil, along a central axis direction of the electrical coil; and a detection unit electronically connected with the electrical coil of each clamping unit and the PWM controller, the detection unit being configured for detecting a back electromotive force representative of the arrival to a target position of a clamping pin and for signaling the PWM controller to stop supplying the pulse signal to a corresponding electrical coil.