Patent GB-370393-A (GB)
Title: Improvements relating to electrical relay devices
IPC: H01H50/88
Filed: 1930-12-31
Abstract: 370,393. Electromagnetic switches and interrupters. WESTINGHOUSE BRAKE & SAXBY SIGNAL CO., Ltd., 82, York Road, King's Cross, London.-(Assignees of Lazich, B. ; 16, Eureka Street, Pittsburg, and Ashworth, H. E. ; 1716, Hays Street, Swissvale, both in Pennsylvania, U.S.A.) Dec. 31, 1930, No. 39320. Convention date, Jan. 14. [Class 38 (v).] Retarding and time-limit devices.-An electric relay having an adjustable time lag of relatively long duration has the operation of the main armature delayed until an auxiliary armature has made a predetermined number of electromagnetically-produced oscillations. As shown in Figs. 1 and 2, the relay comprises a magnetic structure consisting of cores 1, 2, 3 united by a yokepiece 4 and having polepieces 1a, 2a, 3a extending below an insulating top-plate A. Below these polepieces is arranged a pivoted main armature 9 held in bearings 10 and carrying movable contacts 13 .. 16 which play between corresponding upper and lower contacts extending from the top plate. The armature 9 is formed with lateral extensions 9a, 9b which in the inoperative position rest against polepieces 24 of auxiliary electromagnets 23. The outer cores 1, 2 are provided with windings 5, 6 each consisting of two coils 5a, 5b and 6a, 6b connected as shown in Fig. 9, and the centre limb 3 has threaded thereon copper retarding washers 8. The cores 23 of the auxiliary electromagnets 22 are connected to the outer polepieces 1a, 2a by magnetic members 22 so that when the operation of the relay is initiated by closing the switch H, Fig. 9, the coils 5a, 6a are placed alternately in circuit with the battery G through a switch 31 controlled by the oscillating auxiliary armature 27 of a time delay mechanism, the major portion of the flux passing through the armature 9 enters by way of the auxiliary polepieces 24 so holding the armature in its lower or inoperative position. The auxiliary armature 27 is pivotally mounted, as shown in Fig. 7, on a spindle 26 mounted in bearings formed in the bifurcated end of polepiece 3a so as to be attracted alternately to the downward extensions 28, 29 of polepieces 1a, 2a, the armature carrying a movable contact 31 moving between fixed contacts 36, 38 connecting the coils 5a, 6a alternately to the battery G and thus maintaining the armature in oscillation. Also mounted on the shaft 26 is a planetary gearing for an intermittently stepped contact operating-member which determines the number of oscillations of the auxiliary armature which must occur before the main armature is operated. The drive for the planetary gearing is transmitted by a pawl 39 on the armature 27, Fig. 8, which steps round a ratchet wheel 41 fitted with a return checking pawl 42, the driving pinion 43 being secured on the outer end of the drive shaft 26. This gearing is brought into operation by a clutch member consisting of a magnetic plate 53 pivotally mounted at 54 and provided with counterweights 55, the plates 53 being held magnetically against the polepieces 1a, 2a during the energization of the windings 5, 6 and carrying a knurled stud 52 which is thereby held against the clutch wheel 51 to prevent rotation of the gear wheel 49 thus enabling the planetary gear to function. At the end of stepping round of the contact-operating member a stud 72 operates to bring contacts 71, 70 into engagement, so closing the switch E. This causes the energization of the auxiliary windings 23 from the battery 9 when the contacts 31, 36 are again closed, the auxiliary windings being so wound as to produce flux in the cores 21 in a direction opposite to that in which the flux had previously passed through them from windings 5a or 6a. Thus the main armature 9 commences to move upwardly towards the polepieces 1a, 2a. The contacts 13, 18 are arranged to remain in contact slightly longer than the contacts 14, 18 and 15, 18 so that during the upward movement of the armature the winding 5a is substituted for the winding 6a and at the end of the armature stroke a maintaining circuit through windings 5a, 5b 6b, 23 in series with switch E is completed. Winding 6a is short-circuited at contacts 15, 75 so that the oscillation of armature 27 ceases. The armature 9 is thus maintained in its attracted position until the main control switch H is opened, when the parts resume the positions shown in readiness for a subsequent operation. The oscillations of the armature are relatively slow, producing a relatively large time lag by reason of the copper washers 8 in the magnetic circuits of the coils 5a, 6a and the rate of oscillation of the armature 27 may be adjusted by variation of the number and size of these washers. A further adjustment of the time lag may be produced by altering the number of oscillations of the auxiliary armature before the contact-operating member F is stepped round to its operating position and this is effected by rotation of a square head 56a attached to a worm which varies the relative position of the gears in the planetary gearing, this adjustment being indicated by a pointer 47a on a segmental scale 60 and being effected by a suitable tool inserted through a covered orifice 72 in the top plate A. The top plate carries the terminals of the relay operating and controlled contacts.