Patent GB-1246133-A (GB)
Title: Automatic dialling systems for telephones
Inventor: MARTIN GAVIN PATRICK BLANDY
IPC: H04M1/274
Filed: 1968-03-25
Abstract: 1,246,133. Repertory diallers. JOSEPH LUCAS (INDUSTRIES) Ltd. 27 May, 1969 [25 March, 1968], No. 14214/68. Heading H4K. A repertory dialler uses a stack of discs to store each telephone number, with each stack consisting of digit discs separated by spacer discs, and being driven through a differential gear unit by an electric motor. The differential gear unit 17 has an input shaft 17a connected to electric motor 16 and an output shaft 17c which is connected to dial mechanism 19. The planet wheels of the gear unit are connected to carrier 17b which has a toothed periphery 61 and drives a lay shaft 63 through pinion 62 and thereby shafts 15 which contain the disc stacks. Cams 25, attached to shaft 17a, and cam 33, attached to carrier 17b, control the operation of the dialler both when dialling and when setting. The number required to be dialled is selected by operating the respective pushbutton 13 which disengages finger 24 and operates microswitch 26 to start motor 16. Shafts 15 are rotated until finger 38 engages with a slot in the first disc 18, causing pawl 39 to engage wheel 41 and stop shaft 15 and planet carrier 17b thus transferring the drive to shaft 17c and rotating dial mechanism 19. When shaft 17a has made a complete revolution, cam 25 causes the motor to be switched off. Cam 42 disengages pawl 39 from wheel 41 and finger 38 from the slot in the first disc. Shaft 17c and shaft 15 are driven by the action of the dial spring in mechanism 19 to transmit the required number of dial impulses, and to complete a half revolution of shafts 15. Finger 38 moves axially through the slot in the separator disc into register with the second memory disc when the mechanism is at its initial position. The cycle is repeated until the last digit is sent and the mechanism is then returned to its initial datum state by providing one or two additional discs depending on whether the total number of digits dialled is odd or even. The slots in these additional discs are positioned so that finger 38 cannot engage with them so that no impulses are sent. The dialler is set by depressing the respective pushbutton 13 and lifting rod 51 which releases pawl 46 and finger stop 54 so that its associated microswitch opens. The first digit to be set is dialled on the finger plate and the stop 54 moved to operate the microswitch and switch on motor 16 which causes pawl 46 to engage wheel 45 and lock shaft 17c. In the process of dialling the digit, shafts 15 were rotated by an amount equivalent to the digit dialled but in the reverse direction. From this position the shafts are now rotated in the opposite direction and the memory disc rotates until stopped by finger 38 entering one of the slots in the disc. The shafts continue to rotate until cam 25 has completed a full revolution when the motor is stopped and pawl 46 and finger 38 disengaged. The dial returns to its initial position and drives shafts 15 forward until they reach their initial position when finger 38 moves axially through the slot in the separator disc to engage the second memory disc. The remaining digits are then set and finally rod 51 is depressed so that the mechanism functions similarly to the end of a dialling sequence and resets itself after one or two additional cycles. The dialler may be provided with a tone monitor so that sending should not precede the reception of dial tone. A pushbutton 13, when held fully depressed connects up the monitor and causes the line to be looped but does not initiate sending. When dial tone is heard the button is released to its normally depressed position to cut off the monitor and initiate sending. If an access pause is required, e.g. when seizing an exchange line in a PABX, a memory disc can be set to provide no digits out when read and this is accomplished by using the extra finger hole 21a provided in the dial. Alternatively a delay can be provided by the electric circuitry which is modified so that in a PABX the full depression of a pushbutton 13 stops the mechanism after the first digit has been sent. When the second dialling tone is heard the button is released to its normally depressed position and the remaining digits are sent.