GB848477A - Improvements in or relating to electro-magnetic relays - Google Patents

Abstract

848,477. Telephone sets. AUTOMATIC TELEPHONE & ELECTRIC CO. Ltd. Feb. 19, 1959 [March 26, 1958], No. 9651/58. Class 40 (4). In a telephone set, suitable for use by a partyline subscriber in the system described in Specification 837,653, wherein a relay is mechanically conditioned, preparatory to its operation, by the removal of the handset, is duly operated from the exchange and remains so until reset mechanically by the replacement. of the handset, the relay has its contact spring pile-up arranged transversely with respect to its yoke and the armature carries a latching member effective in the released condition of the armature to maintain the (or a) moving spring of the pile-up in a position of deflection opposed to the inherent tension thereof, and in the operated condition of the armature to permit the moving spring to be deflected by its inherent tension to a second position, the release of the armature by its restoring spring being effected upon the deflection of the moving spring in a direction opposed to its inherent tension, by the depression of the cradle plungers when the handset is replaced. Operation.-The relay is shown in Figs. 1 and 2 in the operated condition, the handset (not shown) being off and the pivoted plate 12 being urged fully clockwise by the spring 13, the rollers 14 thus raising the cradle plungers (not shown). When the relay is de-energized the armature 24 may, under the action of the restoring spring 28 which engages channel 53 (Fig. 4) of the latching member 26 mounted on the armature, make a barely perceptible initial movement in the release direction, but this is stopped by the lower face of the tooth 52 (Fig. 4) of member 26 engaging with the edge of the relatively rigid arm 41 which is bonded to the moving spring 41a. When the handset is replaced the resulting anti-clockwise rotation of the plate 12 causes the arm 15 to depress the plunger 16 thus moving the arm 41 clear of the tooth 52 so that the spring 28 may restore the armature 24. The downward movement of arm 41 also causes the moving springs 41a and 34 to close their lower contacts. When the subscriber lifts the handset to initiate a call the arm 15 moves upwards and inherent upward tension of the spring 41a tends to move arm 41 upwards. However, this movement is stopped, and change-over of the contacts is prevented, by the face of arm 41 coming into engagement with the rounded tooth 52 of the latching member 26 (in the released condition of the armature). When, subsequently, the relay is operated from the exchange, the armature 24 is attracted and as the latching member 26 rises the tooth 52 slides across the face of the arm 41 until it disengages, whereupon the arm 41 and spring 34 are permitted to assume the positions shown in Fig. 1 by relaxation of the upwardly tensioned springs 34 and 41a.