Patent ID: 8205446

Claim:
A driving unit for a brake, comprising: a driving device; a hydraulic pump driven by said driving device; a hydraulic cylinder in fluid communication with the hydraulic pump and driven by said hydraulic pump, wherein the hydraulic pump is operably connected with a piston rod to drive the piston rod to reciprocate, said piston rod being drivingly connected with a braking portion of the brake, wherein said driving unit is further provided with a holding device for keeping the braking portion under an operation state, and wherein said hydraulic cylinder includes a piston that is releasably engagable with the piston rod, wherein: the piston of the hydraulic cylinder is moved forwardly to contact the piston rod, with the piston and the piston rod engaged with each other under the action of the driving device; and upon releasing the driving device, the piston of the hydraulic cylinder is moved backwardly to detach from the engagement with the piston rod under the action of a biasing device.