Patent GB-723143-A (GB)
Title: Improvements relating to telegraph transmitting apparatus
Inventor: SAUNDERS RONALD LIONEL SPENCER
IPC: H03M5/00
Filed: 1953-07-16
Abstract: 723,143. Type-printing telegraphy. CABLE & WIRELESS, Ltd. July 16, 1953 [May 16, 1952], No. 12482/52. Class 40 (3). A mechanical translating mechanism which receives signals in a primary equal length code and transmits corresponding signals in a different equal length code, consists of a set of sliding permutation combs, equal in number to the number of elements in each character of the primary code, and a set of blades equal in number to the signals to be transmitted, are arranged to explore the notches of the combs so that the blade corresponding to the signal set brings a transmitting switch member into contact with a cam shaped to transmit the desired output signal. As shown in Figs. 1 and 4, a shaft 2 driven by a motor 3 is geared to a shaft 5 which bears four cams. One of these, cam 7, operates feed mechanism for a tape 1 in which the incoming signals have been stamped. The second cam 8 operates mechanism to stop the feed of tape 1 for repetition operations, the third cam 9 operates means for moving along the line of feed peckers 10 which sense the tape, and the last cam 11 operates a linkage to move the combs under control of the peckers 10 during tape sensing. The shaft 2 also drives a shaft 14 through bevel gearing 13, this shaft carrying cams shaped to produce seven unit signals, which are in the desired output code for this construction. Two further cams are provided on this shaft, one to reciprocate the peckers and the other to operate latch-releasing means whose purpose is explained later. The permutation combs 12 are arranged in parallel with shaft 14 and each comb is associated with a pecker 10. When one of the latter rises through a perforation in tape 1 it releases a linkage 23 driven by the fourth cam 11 on shaft 5 and its comb 12 is driven to the left as in Fig. 1 and 6. The combs are held in their adjusted positions by a ball catch 43 and three additional combs not connected with peckers are provided to furnish control signals. The exploring blades 46 form parts of bell-crank levers all mounted on a common pivot spindle 48 which is moved up and down by an eccentric on shaft 14. If a blade 46 can sink into notches in combs 12 as shaft 14 sinks, its other arm latches a catch arm 57 associated with the particular blade thus storing the signal and also bringing an actuator 59 into co-operation with the corresponding transmitting cam 14a on shaft 14, and causing corresponding transmitting contacts 73 to transmit the signal in seven unit code. The latch-releasing means previously mentioned frees the arm 57 when these operations are complete. The shaft 14 with its associated cams is detachably secured between end stub shafts 86 so that it can be replaced by shafts bearing different signal cams when required. Different modes of transmission can be obtained by turning a knob 92 fixed to a spindle 93. In normal operation the tape moves continuously and each signal is transmitted once. In a second mode of operation the tape moves intermittently and each perforation is explored twice by the peckers thus giving an immediate repetition of each signal. In this case, adjustment of knob 92 renders a linkage driven by cam 8 effective to disable every alternate driving stroke of a ratchet and pawl mechanism that feeds tape 1. In a third method of operation cam 9 intermittently rocks the peckers about an axis at their lower end so that they explore the tape several signals back and thus passages of several signals can be repeated as a whole. One of the uses of the additional control signal combs mentioned above is to permit a distant station to start the repetition mechanism automatically when it receives a mutilated signal. Specification 657,751 is referred to.