| 摘要 |
This programmer control device comprises a programme-cam unit and a reversing cam unit disposed coaxially and driven for step by step rotation by rocking pawls, notably a pawl cooperating with concentric sets of teeth. The beak of this pawl comprises a stud engaging a slot formed in the first portion of a movable deceleration element having its second portion connected to the first portion by a spring and provided with an extension adapted to be locked in its forward or operative position by the movable core of an electromagnet. The slot formed in the first portion is so inclined that upon each backward movement of the pawl the fall of the beak of this pawl behind each tooth is damped out by the stud in sliding contact with the side of the slot, so as to carry along the deceleration element which may be of the frictional contact type. On the other hand, when the second portion of the movable deceleration element is locked by the core of the electromagnet upon each backward movement of the pawl which in this case cannot drive the first portion against the force of the spring, the stud is caused to slide in its slot and to lift the beak of the pawl off the teeth of the corresponding concentric set of teeth. |
