A transmission mechanism includes a link lever, a fan-shaped lever, a spring mechanism and a thrust shaft pin. An outer end of the link lever includes a pin hole and an inner end includes a chute. A cam shaft pin passes through the chute and moves in the chute to drive the link lever when a motor cam rotates. A roller is mounted between the pin hole and the chute. The fan-shaped lever is connected to a main shaft and includes a first chute. The top of the spring mechanism includes a hole. The thrust shaft pin passes through second chutes on two side plates, the first chute, the hole, and the pin hole and links the link lever, the fan-shaped lever and the spring mechanism. The thrust shaft pin compresses the spring mechanism to store energy and drives the fan-shaped lever to rotate and a contact to move.