Patent GB-484475-A (GB)
Title: Improvements in or relating to date indicators and/or recorders
IPC: G04C17/00
Filed: 1936-10-31
Abstract: 484,475. Date indicators. STANDARD TELEPHONES & CABLES, Ltd. (Hatton, W., and Kozma, L.) Oct. 31, 1936, No. 29639. [Class 106 (iv)] An automatic date indicator is controlled by circuits comprising selective switches of telephone type for counting the number of days in each month and the number of months in the year. At the end of each month the date indicator is advanced rapidly to return the indication to unity. The invention is shown as applied to the control of a time and date recorder for use in telephone systems. An earth impulse is received every five minutes by a wire 3 and is passed to a wire 2 to advance the time wheel. At midnight, an impulse is also received by a wire 4 and controls the sending of earth impulses by a wire 1 to operate the daterecording wheels, not shown. These latter comprise a units wheel having ten steps of movement, a tens wheel having five steps and rotating one step for each complete rotation of the units wheel, and a months-name wheel having twelve steps and rotating one step for each complete rotation of the tens wheel. Normally, one impulse is applied to the units wheel, but at the end of a month of, say, 31 days, 20 impulses are sent to turn the date figure wheels through 40 and 50 to 1, a unit being transferred to the months-name wheel as the tens wheel passes to zero. The impulses over wire 3 arriving at five-minute intervals operate relay Mcr which causes the operation of relays Srr and Cmr, the latter giving the ground impulse to wire 2. A slow relay Sor then operates to release Srr and Cmr. At midnight, the impulse over wire 4 operates a relay Mir, so that when Mcr is next operated, Cmr causes the operation of a relay Ohr which sends an impulse along wire 1 to advance the date indication to (e.g.) 2nd Jan. Relay Ohr also operates a relay Cr which completes a circuit for the stepping magnet MDM of a step-by-step switch MD through the wiper b and the first four multiplied contacts of another step-by-step switch MJ. Switch MD is thus advanced one step. These operations are repeated until midnight on 12th Jan. At the next impulse, arm a of switch MD causes the operation of the stepping magnet MJM of switch MJ, this switch moving to its second position and switch MD returning to its initial position. A similar action occurs at midnight on 24th Jan., switch MJ then moving to position 3. At midnight on 31st Jan. MJ is in position 3, MD advances to position 8 and the date wheels register 32nd Jan. Relays Ar and Drr operate, Drr removing earth from a wire 5 to disable the printing mechanism. Relay Ar connects earth to the end of the winding of a relay Br and also connects a point in the said winding to an earth interrupter CJS. When CJS moves on to its insulated part, Br operates to connect Ohr to CJS so that earthed operating impulses pass to Ohr from CJS to advance the date wheels and to operate relay Cr. After 16 impulses MD is in position 12 and MJ in position 4. At the next impulse MJ advances to position 5 and MD to position 1. Then MJ is advanced to position 6 and the date wheels show 00 Feb. The next impulse advances the date wheels to 1st Feb. and moves switch MJ to position 7 whereupon this switch steps itself back to position 1, relays Ar, Drr and Br release and a switch M is given one step. The ordinary action then continues until midnight on 28th Feb., when MJ is in position 3 and brush b of MD advances to position 5, whereupon interrupter CJS is caused to control the advance to 1st March, switch M is advanced to position 2 and a switch MA is advanced to position 1. The switches M and MA each have 24 steps, the switch M moving every month but the switch MA moving only at the end of every even month. These switches are arranged to cause the correct date registration at the end of February in ordinary and in leap years.