Patent GB-959628-A (GB)
Title: Improvements in or relating to devices for sending or receiving coded electrical signals
Inventor: PUY CLARENCE EDWARD DE
IPC: H04M1/272
Filed: 1962-10-11
Abstract: 959,628. Electric selective signalling. SECODE CORPORATION. Oct. 11, 1962, No. 38589/62. Heading G4H. A device for sending coded signals comprises a rotable spring-loaded toothed disc Fig. 1 having code pins 170 in selected ones of peripheral holes 173, the disc being driven in steps by a pawl 100 operated by a coil 66, Fig. 2, the driving mechanism being interrupted when one of the pins reaches an abutment controlled by a slow-to-release coil 70 which, after a predetermined period, permits the driving mechanism to advance the disc until the next pin reaches the abutment. The pawl 100 is withdrawn one notch by energization of the coil 66 and advances the disc when the coil is deenergized by means of a spring 102. A pawl 60 engages between teeth to prevent backwards motion. The abutment 166 is part of a plate 164 pivoted at 162, Fig. 4 to a plate 156 pivoted in turn to an extension 154 of the armature 80 of the coil 70. The armature is pivoted at 46 and a spring 167 urges plate 164 clockwise. When the abutment 166 is engaged by a pin 170, Fig. 5, the plate 164 is rotated into contact with a bracket 150 (Fig. 1) as shown in Fig. 6. Bracket 150 is mounted on a contact arm 134 and causes separation of contacts 142 and 144. These contacts are mounted on the armature 80 of the slow-to-release coil 70 which is de-energized by the opening of the contacts. Rotation of plate 164 also causes a lug 169 to lift the pawl 100 and prevent further stepping. When the armature falls out the contacts close again and plate 164 is lifted radially to allow the pin to pass the abutment 166 so that the plate returns to the position of Fig. 5 to allow stepping to begin again under the control of a snap-action switch 88 having two sets of contacts, the switch being controlled by arm 84 on the armature 76 of fast coil 66. One pair of switch contacts is in the circuit of the coil 66 and the other connects a battery to either of two lines over which the pulses are transmitted. When the switch closes to energize coil 66, coil 70 is also energized. When armature 76 picks the switch opens to de-energize the coil so that a stepping oscillation takes place which continues until the first pin strikes the abutment 166. The pawl 100 is raised by plate 164 to stop the stepping and contacts 142, 144 open to cause the slow-to-release coil to partially release to let the pin 170 get past the abutment 166. The next series of steps then begins so that a series of groups of pulses are generated separated by longer intervals and transmitted on mark and space leads. Receiver. The device can be used to respond to a particular sequence of pulse groups e.g. 5-5- 6-7 as indicated in Fig. 1. The switch 88 is not used for this. The first four pulses of the first group, applied to coil 66, steps the disc to the position of Fig. 5 where the first pin 170 is in contact with abutment 166. Coil 70 is in series and is energized by the same group, the armature remaining in the picked position throughout the group. The last pulse of the first group turns the plate 164 and the interval between groups allows the armature 80 to begin to release so that abutment 166 swings out of the path of pin 170. An upstanding ear 158 on plate 156 then contacts the pin as shown in Fig. 7 and prevents full release of the armature 80. Had the first group contained less than five pulses, the pin 170 would not have been in this position and the armature would have fully released, drawing the pawl 60 out of engagement with the toothed disc and allowing the disc to return to the initial position under the action of its spring 44. If more than five pulses had been received the abutment 166 could not have moved radially to let the pin 170 past but it would instead have been carried to a point where, when the armature 80 was released, the ear 158 would miss the pin 170 and allow the armature to release as before. The operation is the same with the following groups of pulses. At the end of the last group an upstanding part 176 on an end pin-member 174 engages a contact pin 112, Fig. 1 signalling e.g. on a lamp that the correct sequence has been received. The pulse groups may be generated by a dial. The switch 88 may be replaced by a relay operated by transistor circuits.