Patent GB-366127-A (GB)
Title: Improvements in and relating to electric relays
IPC: H01H50/88
Filed: 1930-10-30
Abstract: 366,127. Electromagnetic relays. BRITISH POWER RAILWAY SIGNAL CO., Ltd., Windsor Works, Slough, Bucking- hamshire, PARK ROYAL ENGINEERING CO., Ltd., Cumberland Avenue, Park Royal, London, GLENN, S. L., 3, Central Buildings, Westminster, and OGILVIE, J. A. G., Cumberland Avenue, Park Royal, London. Oct. 30, 1930, No. 32682. [Class 38 (v).] Retarding devices.-An electric relay for use in railway signalling circuits is arranged after energization to release a weight-controlled escapement mechanism so that the weight drives the escapement mechanism throughout its downward stroke and after a predetermined adjustable time interval operates a rocking bar carrying the relay contacts. As shown in Figs. 1 and 2 the core 8 of the solenoid 6 mounted on the insulating top plate 1 of the relay is weighted at 28 and has a downward extension to which is secured at 12 two slotted arms 10, 11, which normally, by engaging a pin 14, hold two levers 15, 16 in a position in which adjustable weights 21 at their ends are in a raised position. On energization of the solenoid, the raising of the core with the arms 10, 11 frees the levers 15, 16 which throughout their downward motion drive an escapement-controlled clockwork mechanism 27 through a pawl 19 pivotally mounted at 20 to a pin bridging the ends of the weight-carrying arms 15, 16, the drive being transmitted to a toothed wheel 18 geared to the clock-mechanism. At the end of the retarded stroke of the arms 15, 16 a projection 48 on a pivoted spring-controlled contactoperating lever 34 escapes past the end of the raised surface 49 of a cam 47 rotating with the wheel 18 and so operates a rocking contact bridge 30 through a link 36 and bell crank 37. The contacts carried by the bridge 30 may be of the type described in Specification 315,926, [Class 38 (v), Electric switches &c.]. On deenergization of the operating electromagnet 5 the fall of the core raises the weight-carrying arms 15, 16 in readiness for a subsequent operation, the pawl 19 slipping around the ratchet teeth of the wheel 18. The contact operating arm 34 is restored to its former position, in which it may cause the engagement of back contacts, by an extended portion 45 of the arm 11 engaging an adjustable projection 46 of the arm 34. Adjustment of the timeperiod may be effected by varying the operating stroke of the weighted arms 15, 16 either as shown by varying the position of an adjustable stop 75 on a screwed stem 74 depending from the relay top plate, or, Fig. 3 (not shown), by means of a stop arm pivoted below the relay top plate which simultaneously varies the lower position of the solenoid core. The adjusting screw for the latter form of adjusting mechanism is interlocked with a cam mechanism for raising the pawl 19 off the ratchet wheel 18 during adjustment. To ensure time-controlled operation of the contacts in case the pawl 19 is fractured an auxiliary cam plate may be provided on the shaft 17, this plate being connected to the pawl 19 by a slotted link and having a recess allowing a projection on the arm 34 to enter at the end oi the normal stroke of the arms 15, 16. Duplicate pawls and, if desired, duplicate ratchet wheels with staggered teeth may alternatively be provided to guard against this contingency.