Patent GB-813258-A (GB)
Title: Improvements in counting mechanism
Inventor: ROBINSON SYDNEY
IPC: H03K21/00
Filed: 1954-03-06
Abstract: 813,258. Electronic counting - apparatus. JACKSON, S.W., ROBINSON, S., and HOWDEN, J. M. [trading as BRITISH NORTHERN ELECTRICAL APPLIANCES]. May 11, 1955 [March 6, 1954], No. 6607/54. Class 106 (1). A multicathode tube counter has printing devices associated with each tube which are set up for printing the total while counting is suspended. Printing is initiated by closing a switch A to energize a relay 9 which changes over contacts to provide for a parallel input to the multicathode counting tubes 1... 4 instead of the normal series arrangement in which pulses to be counted are generated by moving contacts C. The closing of the switch A also starts a motor 18 driving a shaft carrying three cam discs 19, 20 and 21, the first of which, by closing contacts 25, maintains the circuit of the motor for a complete revolution. Cam discs 20 and 21 each generate two series of ten pulses with a pause between, the pulses from cam disc 21 lagging slightly behind those from cam disc 20. The pulses generated by cam disc 20 are fed, via the contacts of relay 9, to all the counting tubes in parallel. As each counting tube passes from 9 to 0 an output signal, amplified by an associated tube 5...8, is applied, again via the contacts of relay 9, to an associated relay 10 ... 13. These latter relays are of the polarized type in which the contacts take up one position when the relay is first energized and only revert to their original position when the relay is energized a second time. Energization of one of the relays 10 ... 13 closes contacts which connect a corresponding print wheel control magnet 14 ... 17 into the circuit which is impulsed by the cam disc 21. Thus, after each counting tube 1 ... 4 has been stepped through " carry over " by pulses from the cam disc 20, the remainder of the first ten pulses from the cam disc 21 serve to step on an associated print wheel until the latter registers the digit previously standing in the counting tube. The pause provided by the gap between the two groups of teeth on the cam discs allows time for the actual printing operation; then the generation of the second series of ten pulses drives all the counting tubes through a further cycle during which the print wheels are rotated to their initial positions. The second " carry " signals from the counting tubes serve to reset the polarized relays 10 ... 13 as each respective print wheel reaches zero again. When the cam disc 19 completes a revolution the contacts 25 open and the circuit of the driving motor 18 is broken. A relay 30 controls a circuit including a condenser 31 and coil 33 which arrests rotation of the shaft abruptly when the contacts 25 open. A switch B can be used to zeroize the counter after printing, if desired. In a modification, the print wheels are reset mechanically and the cam discs 20, 21 supply only one series of ten pulses. Adaptation to other radices, such as inches and feet, is mentioned. Instead of cam discs, other devices such as uniselector switches may be used to produce the read-out pulses. The printing devices may be in the form of cut-outs or stencils to which a miniature spray gun is applied. For continuous counting, two banks of counting tubes may be used with changeover means acting at predetermined time intervals to allow for the printing of intermediate results while counting proceeds.