| 摘要 |
Sprung slewing arm for use on an automatic door opener. The slewing arm is comprised of a tube sleeve (35) and an axle (12). One end of the axle is stuck into the tube sleeve through a plug (42) in one end of the tube sleeve. A spring (46) pre-stresses the axle in relation to the tube sleeve. The new thing about this invention is that a micro-circuit breaker's (20) contact function is tested before the opening motion of the door is carried out. Another new thing about this invention is that a piston (26) is loosely threaded on it in the form of a plug (25) at the axle end. The piston has a cylinder (26) working together with a cam surface (54) on the motor arm. The final phase of the door's closing motion produces a relative movement between the axle and tube sleeve in the off-centre housed cam surface (54), at which the spring is tensed. When an opening motion is initiated the cam surface (53) is turned under and the sprung axle (12) performs a relative motion in the opposite direction. The last named motion is sensed by the micro-circuit breaker whose contacts are connected. If the contact connection is not made within 2-3 seconds after the opening motion has been initiated an electric current is designed to break the opening movement and reverse the motor.<IMAGE> |
