GB564246A - Clutch for telecommunication selector switch - Google Patents

Abstract

564,246. Automatic exchange switches. STANDARD TELEPHONES & CABLES, Ltd. June 18, 1943, No. 9838. Convention date, July 15, 1942. [Class 40 (iv)] [Also in Group XXIV] In a switch, e.g. of the kind described in Specification 558,416, driven by cooperation between disengageable friction surfaces on the switch shaft and on a constantly driven power shaft common to a number of switches, one of each pair of surfaces is of hard material provided with ribs and the other of semi-hard material, such as rubber, which in use receives indentations from the hard ribs and so compensates for inaccuracies in the alignment of the shafts. In a preferred arrangement, the ribbed surface 7a is formed on a member 8a which is adjustably secured to a sleeve 28 sliding on the switch shaft. When the magnet armature 15a is attracted, the friction surfaces are forced into contact by a spring 14a. When the armature is released, the sleeve is withdrawn against a spring shock-absorbing disc 32 by engagement of the bent ends of springs 25 with a rubber inset 31 in a flanged portion of the sleeve. As the movement is completed, the bent ends of the springs are flattened and cause backward rotation of the shaft sufficient to compensate for the over-run due to momentum after disengagement of the friction surfaces.