904,683. Photographic type composing apparatus. INTERNATIONAL PHOTON CORPORATION. July 21, 1958 [Oct. 1, 1957], No. 23370/58. Class 98 (1). In photographic type composing apparatus in which characters are photographically recorded in succession in suitably spaced arrangement to form a line of composition as a result of relative movement between a character printing position and the recording material and means for effecting interline leading is provided, the leading means are driven by a drive control assembly which includes clutching means for transmitting drive from a driving member adapted to be continuously driven to a driven member capable of being driven at different speeds, a pulse generator adapted to generate a pulse in response to a drive being applied to the driven member to rotate it through a predetermined angle, and a pulse counter connected to receive pulses from the generator and arranged when the count reaches a prearranged value to initiate disengagement of the clutching means. As shown, leading of the film 126 is effected by sprocket 128 driven via shaft 134 by the output shaft 146 of a differential 150 having an input gear 152 driven by fine leading mechanism 156 for effecting movements up to nine-tenths of a point and an input gear 154<SP>1</SP> driven by coarse leading mechanism 158 effecting movements in points, leading being effected on receipt of an end-of-line signal depicted as equivalent to the closing of key LRK (Fig. 4) producing a potential on terminal T100. The fine leading mechanism is controlled by two-position keys 1 to 9 of a bank 210, the keys operating binary-related contacts connected to contact arcs on a card 194 having a rotatable arm 192 on a shaft 164 which in the rest position to which it is urged by a coil spring 190 connects all the binary circuits " 1," " 2," " 4," " 8 " to the key bank 210. Thus, on receipt of an end-of-line potential on terminal T100, if any of the keys of bank 210 is closed, relay FI is energized, energizing the fine leading clutch magnet CLF so that shaft 164 is clutched to the continuously rotating sleeve 166 and drives via pawl and ratchet 176, 178 input gear 152 until the arm 192 comes to a position in which the circuit to the relay FI is broken, when clutch magnet CLF is de-energized and fine leading is arrested. The coarse leading mechanism is controlled by two-position keys K0 ... K9, K00 ... K40, the contacts of which are arranged so that each combination is connected to one contact 1 ... 49 on level 224 of a 50-position stepping switch LS, which level via brush 228 together with contacts 226 and the keys provides a self-cycling system for the switch, so that this sets itself in accordance with the operated keys, which open the self-cycling circuit via that switch contact which is numerically equal to the sum of the key numbers. The end-of-line signal, indicated as a closing of key LRK, energizes a relay LR, so opening the selfcycling circuit over level 224 via keys K0 to K9, K00 to K40 connecting cam-operated contacts 208 over terminal T101 to the stepping coil of the switch LS, closing movable contact 232 on to the lead to the brush 231 so as to maintain relay LR energized, and closing contacts 234 to energize a magnet LPM. This magnet withdraws a latch 202 from a notched disc 204 on the shaft 196, opens a switch in the initial energizing circuit of the magnet, and closes contacts 236 to energize the coarse leading clutch magnet CLC, clutching the shaft 196 to the continuously rotating sleeve 198, so that gear 154 rotates, driving differential input gear 154<SP>1</SP>. For each quarter-revolution of shaft 196, equivalent to one point leading, cam 206 closes contacts 208 applying positive potential to terminal T101 to maintain stepping of the switch LS and also operating a counter CTR, the purpose of which is not stated. Leading continues until brush 231 arrives on contact 49 on level 230, the holding circuit for the relay LR is transferred to line 229 and contacts 226 so that switch LS steps on to blank position 50 when relay LR and magnet LPM are deenergized. Thereby latch pawl 202 re-engages the disc rim 204, but contacts 236 remain held closed mechanically (see Fig. 3) so that shaft 196 continues to turn to complete an integral number of points leading, whereupon the latch 202 enters a notch in the disc 204 and so opens contacts 236 to de-energize the clutch magnet CLC. De-energization of relay LR re-connects contacts 226 over the key circuit to level 228 of switch LS which then recycles to its preset position determined by the keys. Continuous leading is obtained by holding depressed key VRK as in Specification 904,684; additional leading over the normal interline is obtained after the normal leading has been effected by holding depressed one of keys 240 as long as a signal lamp 254 is alight, thus energizing relay XL which energizes relay LR so that switch LS is caused to self cycle by a circuit via contacts 226 and contacts of keys K0 to K9, K00 to K40 to the additional leading pre-set position, when the lamp 254 is extinguished, whereupon key 240 may be released, de-energizing relay XL, so energizing magnet LPM whereby the required additional leading is added by the stepping of the switch LS; and reverse leading may be effected by first closing two-position key RLK energizing relay RES to operate reversing gear 142. To avoid zero leading occurring, the keyboard is locked by a magnet KBL unless one of the keys K0 to K9, K00 to K40 is operated. A signal lamp 252 is also provided indicating that either the switch LS is self-cycling or the magnet LPM is energized so that no further operation should be initiated whilst the lamp is lit. The shaft 134 driving film sprocket 128 also drives through friction clutch 90 a shaft 92 carrying pulleys for moving downwardly against counterweight action a horizontal bar index 76 of a page make-up indicator which is also provided with margin indicators to allow for inserts such as photographs, the right-hand one being controlled by the justified line length setting mechanism while the left-hand one is controlled by the left margin setting mechanism. On completion of a page, clutch 90 is released by the operator when the horizontal index returns to the top-of-page position.