Patent GB-754121-A (GB)
Title: Improvements in or relating to electric counting apparatus
Inventor: BAYLISS ALAN JOHN
IPC: H03K23/74
Filed: 1953-07-21
Abstract: 754,121. Counting-apparatus. GENERAL ELECTRIC CO., Ltd. June 15, 1954 [July 21, 1953], No. 20228/53. Addition to 644,041. Class 106 (1). A binary counting chain of the type disclosed in the parent Specification is modified by the provision of a suitable feed-back arrangement for use in a binary coded decimal counter. The units denomination, Fig. 2, has four stages, each comprising two relays S, T; U, V; W, X; Y, Z respectively, and associated contacts arranged to operate in such a way that on reception by the stage of an impulse the second relay T, V, X, Z of the stage operates and at the end of said impulse the other relay S, U, W, Y of the stage also operates. The counting chain is adapted for addition or subtraction as determined by a relay RR. In a first example, each decade chain is modified by the provision of a pair of relays P, Q connected as shown to a contact RR5 of the relay RR (not shown), and to contacts of the relays S, U, W, Y. The relays P, Q control contacts P1, Q1 in each decade chain and contacts P2, Q2 at the input to the tens decade chain. The general circuit is such that with the relay RR in the position for addition the stages operate in accordance with the binary code until after the reception of the ninth impulse when as contacts SH, YH are closed relay P operates to change over contact P1 and close contacts P2 so that on reception of the tenth impulse the units decade chain is restored to zero and at the same time an impulse is sent over closed contact P2 to the tens decade chain. The addition operation continues in this manner. With the relay RR in the position for subtraction the contacts RR1-RR5 are reversed and each chain counts downwardly. When all the relays S, U, W, Y are de-energized contacts S2, U2, W2, Y2 are closed so that when relay Q operates contact Q1 is changed over and contact Q2 is closed so that on reception of the next impulse by the units decade relays S, T and Y, Z operate and an impulse is sent to the tens decade chain. Each chain is provided with a meter M connected as shown, to resistances R1-R4 via relay contacts T3, V3, X3, Z3 so that the decimal value of the number registered by the associated chain is indicated. In a second example, Fig. 3, the relay P in each chain is dispensed with the feed-back during addition is effected by connecting the output of the first stage of the chain to the input of the second stage of the chain via a contact Y1 controlled by the fourth stage. During addition the chain operates in the normal way up till the seventh impulse. The eighth impulse effects release of relays S, T; U, V; W, X and operation of relay Y, Z. Contact Y1 is changed over so that ninth impulse will effect operation of relays S, T. The start of the tenth impulse causes relays T and Z to release an impulse being passed through contact RR4 to the input of the tens decade chain which registers a count at the end of the impulse simultaneously with the release of the relays S and Y and the return of the units chain to zero. With the relay RR (not shown), set for subtraction the contacts RR1-RR6 are reversed so that when all the relays S, U, W, Y are de-energized the relay Q is energized opening the contacts Q1, Q2 in the second and third stages of the chain so that the next impulse effects operation of the first and fourth stages, relay Q is released and an impulse passed to the tens decade via contact RR4. Specification 744,364, [Group XXXVIII], is referred to.