Patent GB-393707-A (GB)
Title: Improvements in and relating to road traffic signalling systems and circuit controllers therefor
IPC: G08G1/085
Filed: 1932-02-29
Abstract: 393,707. Road signals for controlling traffic. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London.-(Assignees of Campbell, A. B. ; 3310, Indiana Avenue, and Beyer, C. F.; 1841, Broadway, both in Fort Wayne, Indiana, U.S.A.) Feb. 29, 1932, No. 6109. Convention date, Feb. 28, 1931. [Class 118 (ii).] A road-traffic signalling system comprises a periodically actuated circuit closer for coloured lamps, driven by a motor through change-speed mechanism, a rotating circuit controller member for the signal circuits operated by means actuated by the circuit closer, means for maintaining the circuit closer in a definite relation to the circuit controller member, and means for disconnecting the circuit controller from the signalling devices when the change-speed operating mechanism occupies a predetermined position. A motor 3 drives a shaft 8 through wheels 7, 9 and shaft 8 drives a shaft 11 through reduction gears 12, 13 and bevelled gears 15. A disc 16 on shaft 11 carries contact rings 17, 18 engaged by brushes 19, 20. The disc 16 also carries a contact 22 and a contact 24 on a lever 25, Fig. 11, held from 22 by a spring. Contacts 22, 24 are connected respectively to rings 17, 18 so that when these contacts engage, the brushes 19, 20 are connected together. Keys 29 which may be varied in position in slots 30 move contact 24 to engage 22 and the disc 16, contacts 22, 24 and keys 29 form a rotating circuit closer, closing being timed by varying positions of keys 29. The brushes 19, 20 are connected to the winding 33 of a solenoid, Fig. 11, and when 19, 20 are connected, a circuit from power lines 35, 36 is closed so that plunger 34 rises and turns a ratchet wheel 43 one notch by a pawl 42. The wheel 43 is fixed to the shaft 45 of a contact actuating or controller drum 49 which controls circuits to lamps &c., marked R, A, G. The controller drum comprises a series of spaced discs 50 providing annular slots 51 in which are arranged cam segments 52 which contact rollers 54 on arms 55. In Fig. 11, 70..75 indicate the six cams, 76..81 the six movable contacts and 82..87 the six stationary contacts. By adjusting cams 52, the desired sequence of lamp operation is obtained. The length of total cycle is changed by the gears 12, 13, the sets of gear wheels 100, 103 being fixed on the shafts 8, 104, while the sets of gear wheels 101, 105 are loose on the shaft 102 but are capable of being locked to the shaft selectively by spring-pressed lugs which are brought into engagement with the desired gear wheels by lengthwise movement of the shaft 102. To maintain a definite relationship between the rotating circuit closer and the controller drum 49, a lever 121 tends to come under and prevent movement of the plunger 34 when a lever 123 is moved by a cam 128 on the shaft 45 but the lever 121 is prevented from moving by a cam 129 on the shaft 11 if the correct relationship exists, or is withdrawn when the correct relationship is restored. The shaft 102 is moved by a gear wheel 141 on a shaft 142, which carries toothed ratchet wheels 145, 146 moved by pawls 147 148 in opposite directions when either the electromagnet 149 or 150 is energized. A disc 157 carries numerals indicative of the several gear ratios and above the disc is a pointer 165a which indicates the adjustment. The amount of rotation of the disc 157 is limited by spring fingers 162, 165, which may be adjusted to various positions on the disc. The finger 156 is marked on the front with " Fire," " Flash " and " Off." Closing the circuits of the solenoids 149, 150 moves the ratchet wheels 145, 146 and also cams 167, 168 which raise levers 169, 170 to " Flash " or " Fire " positions. In " Flash " position a ratchet wheel 177 is brought into actuation to make and break the circuit to any desired set of lamps, and in " Fire " position all the red lights are caused to remain burning. For periodically checking the phase relation of the circuit controller and resetting it if it is out of step, a brake-lever 201 is provided which is held out of engagement with the motor 3 by a spring 203 but is moved into engagement with the motor by one of the arms 211, 212, or 213 contacting .the roller 210 if the lever 202 carrying the lever 201 is held down by the electromagnet 207 when this is energized. The circuit of the electromagnet 207 is controlled by a master timer or controller 232, comprising a synchronous induction disc motor 236 driving a disc 238 carrying a pin 239 which opens the circuit to the electromagnet 207 by moving the spring contact 235. The motor is thus held till the stop 239 reaches the contact 235. A number of circuit controllers may be connected in parallel with each other and with a common master controller, the arms 211, 212, 213 being set for the desired phase or time relation among the circuit controllers. The roller 210 is moved to the left in line with arm 212 wlen an electromagnet 221 is energized and to the right in line with arm 213 when electromagnet 222 is energized, thus obtaining three selector positions of the signals of the system but the number may be increased or decreased as desired. If the master timer or controller 232 should stop with its re-synchronizing contacts 233, 234 closed all the circuit controllers connected in the system would be stopped and to prevent this a protective relay is provided, comprising a synchronous disc motor 245 connected in parallel with the master timer 232 which is connected and disconnected to and from -gear 254 by electromagnet 250 which is normally energized, but de-energized each time contact 234 is moved away from contact 233. Normally arm 256 is continuously moved towards circuit closer 259 and released just before it starts to open circuit closer 259, but if the motor 256 stops the arm 256 is brought into engagement with spring strip 260, thereby opening closer 259 and de-energizing the brake magnets 207 of all the circuit controllers. An auxiliary timer V may be provided under the control of the protective relay so that when it operates due to the failure of the main timer the auxiliary timer is brought into action through switch W and electromagnet X. The master timer is provided with ratchets 262, 263 and pawls 264, 265 corresponding to the ratchets and pawls of the circuit controller. It also has a disc corresponding to disc 157 showing the gear ratios and the " Fire," " Flash " and Off " positions. A retarding lever 269, operated by an electromagnet 270 which is energized through a switch 271 controlled by electromagnets 272, 273 acts to hold the master timer behind the circuit controllers. If it is desired to operate the signals manually the switch 131 is moved to connect contacts 132, 133 which causes the lever 121 to be held by a solenoid 134 in inoperative position, and depression of a push button 139 then actuates solenoid 33 to rotate controller drum. Specifications 247,209, [Class 35, Dynamo-electric generators &c.], and 392,314 are referred to.