Patent GB-537019-A (GB)
Title: Improvements relating to control devices for railway signalling systems
IPC: B61L19/06
Filed: 1939-11-30
Abstract: 537,019. Railway signal control devices ; switches. TOMLINSON, A. V. (Union Switch & Signal Co.). Nov. 30, 1939, No. 31164. [Class 105] [Also in Group XXXVII] Relates to control devices for railway signalling or routesetting systems, particularly of the kind described in Specification 499,340 wherein a selected route is set up by the successive operation of entrance and exit buttons appropriate to the desired route, the buttons being mounted on a panel which provides a selectively illuminated diagram of the track layout, and wherein each button can be pushed in from normal position to close normally-open contacts, or pulled outwards to open normally - closed contacts. Each controller, formed as a unitary structure readily removable for inspection or repair, includes a movable member operable in either direction against spring action from a normal central position to cause operation of a traffic-control device, which, when effected, operates a lamp or other visual indication device carried by the movable member. Figs. 1-4 show the member 16 mounted to slide between guides on a tray-like base 8 the front end of which carries a bearing 12 through which projects a tubular operating member 13 with terminal button or knob 14. Member 13 is screwed into and clamped in a divided collar 15 on member 16 and contains a glass rod 35 the outer end of which is lightly frosted, the inner end being exposed in a chamber 40 leading to two lamp-holding recesses 38, 39 in member 16. These recesses are covered by an L-shaped member 41 the end-wall of which has soldered thereto a pair of bayonet-type lamp sockets. The lamps 36, 37 may be differently coloured, say red and green but as shown are clear, colour filters 43, 44 being disposed in recesses between the lamps and the rod 35 through which illumination is seen by the operator. The lamp leads are connected with fixed contacts 32, 33 and their circuits are selectively controlled by means, not shown, forming part of the system in which the controller is used. The base 8 is mounted on a fixed bracket 50 and is detachably retained by a shouldered stud 55 co-operating with a key-hole type of slot in the bracket and carried by a spring 11 which is depressed to effect release. A spring-clip 55a may be applied to the stem 27 of the stud to prevent accidental depression of the spring. The movable member 16 is retained in and returned to normal central position by springs 57 riveted to bracket 50 and having terminal rollers 38 co-operating with the inclined walls of V-shaped recesses formed in member 16. As shown, the controller comprises two banks of controlled contacts S1, S2, each comprising fixed spring contacts 23 resting against stops 24, and movable contacts 21 having curled ends which co-operate with inclined cam surfaces 30, 31 formed on the rear portion of member 16. The contacts are mounted between insulating clamping blocks 18, 18a, 18b mounted on base 8. The cam surfaces may be arranged to effect any desired contact operation, but as seen in plan, Fig. 1, the contacts of bank S 1  are normally open, the ends of contacts 21 resting at the lower end of surface 31, whilst contacts S are normally closed contacts 21 resting at the upper end of surface 30. When button 14 is pressed in contacts S 1  are closed, contacts S 2  remaining closed, and when button 14 is pulled out, contacts S, remain open and contacts S 2  are opened. The blocks carry fixed contacts 26a leading to the fixed contacts 32, 33. Fig. 6 shows an alternative spring arrangement for retaining the movable member in and returning it to normal central position. A plate 61 of the movable member provided with lamp casing 60 also carries a housing 64 with perforated end walls so that it can slide along a fixed rod 62 carried by a block 63 secured to base 8. A compression spring 69 surrounding the rod bears against washers 67, 70 within the housing and resting against abutments 66, 68. When button 14 is operated in either direction, housing 64 carries with it one or other of the washers, the other washer being held against its abutment, thus effecting compression of the spring which restores the device to normal position when button 14 is released. The operating cams and controlled contacts are shown disposed above housing 64.