Patent ID: 8222781

Claim:
An overload protection device comprising: a rotatable shaft driven by a motor comprising a rod and a driving arm extending outwards from the rod, a connection pole being formed on an end of the driving arm that is away from the rod; a driven wheel rotatably engaged with the rotatable shaft at a distal end of the rotatable shaft, the driven wheel comprising an inner surface facing towards the rotatable shaft and a protrusion extending outwards from the inner surface, the protrusion having a sidewall facing the rotatable shaft and a cutout being defined in the sidewall of the protrusion; and a transmitting mechanism comprising an resilient member and two arms connected to opposite ends of the resilient member and also rotatably connected to two opposite ends of the connection pole, and wedged in the cutout for driving the driven wheel to rotate following the rotatable shaft; wherein, when the motor is overloaded, the torque applied on the arms by the drive force of the motor becomes greater than the torque applied on the arms by the resilient force of the resilient member, the resilient member can no longer hold the transmission mechanism in a wedge shape, the arms become parallel each other to slide out of the cutout to protect the motor.