Patent GB-658956-A (GB)
Title: Facsimile transmission apparatus
IPC: H04N1/06
Filed: 1947-02-21
Abstract: 658,956. Copying-telegraphy. CREED & CO., Ltd. Feb. 21, 1947, No. 5135. Convention date, Feb. 25, 1946. [Class 40 (iii)] Facsimile scanning apparatus comprises a rotatable transparent cylinder within which an opaque sheet is mounted so that the matter to be transmitted faces the inner surface of the cylinder and is scanned through the transparent wall of the cylinder by a source of light and associated light-sensitive element, both mounted exteriorly of the cylinder. In the apparatus described the matter to be transmitted is mounted on a number of transparent cylinders which are sequentially brought into a position in which they are set into rotation and scanned by a single electrooptical device, comprising the light-source and the light-sensitive element. The cylinders 23 are mounted on shafts 26 carried by a turntable 18 and an integrally formed disc 19 forming a pulley by which the turret TM comprising the cylinders is rotated by a motor 39. The cylinders are transparent and the copy to be transmitted is held against the cylinder surface by cylindrical sectors 33 urged outwardly during rotation and having guiding pins 35 located in slots in the base 27 of the cylinders. The pulley carrying the cylinders is rotated by a pulley 46, Figs. 3, 7, having a pin 47 engaged by a spring 48 mounted in an axial extension 44 carried by a disc 42 driven from the shaft of the motor 39. The cylinder 23a in the scanning position is rotated by the engagement of a pin 67, Fig. 3, on its shaft 26 with an axial projection 66 on a disc 58 which is frictionally clutched to a sleeve 57 driven by a motor 54, the driving operation being effected by the upward movement of the sleeve 57 and disc 58 by a forked lever 70 operated by an electromagnet 72. A brake 74 of rubber or leather is provided for each shaft 26 so that the cylinder in operation is brought to rest immediately the driving connection 66, 67 is broken. The apparatus is set into action and its time of operation controlled by a rotatable cap 155, Figs. 5, 8, having a spring-actuated plunger 160 engaging shaped radial grooves 161 in a bush 153, the grooves having an angular spacing of 60 degrees corresponding to that of the six cylinders 23 on the turntable. The cap 155 which has an indicating projection 155<SP>1</SP> is mounted on a shaft 156 carrying at its lower end a cam 159, Fig. 10, provided with a flat 159<SP>1</SP> and engaging an arm 165 of a switch 164 which is held closed by the engagement of the arm 165 with the circular surface of the cam, but is opened when the flat 1591 engages the arm 165. The cam 159 is rotated by the turret TM by making the rod 156 a tight fit in a plug 153 secured to an extension 17 of the turntable 18. When a cylinder 23 has been brought to the scanning position the turntable is locked against movement by means of a pivoted latch 166, Fig. 7, having a recess 170 engaging the shaft 26 of the corresponding cylinder. When the turret is to be moved, the latch is withdrawn by a magnet 172 operated approximately simultaneously with the motor driving the turret. A switch 180, open when the turret is stationary, is closed by the engagement of the latch with a roller 1831 on an arm 183, when the shaft 26 engages a curved portion on the latch. A second pivoted lever 175, Fig. 3A, co-operates with a roller 184<SP>1</SP> to open a switch 181 which is closed when the turret is stationary. Scanning operation. The photo-electric apparatus, Fig. 3, comprising a light source 89, projection tube 90, pick-up tube 91 and photoelectric cell 92 is mounted in a carriage CR which is moved positively downwards during the rotation of the cylinder 23a being scanned and freely returned to normal position by spring drums 139, 140 connected to spaced points on the carriage. The downward movement is effected by the engagement, under control of a solenoid 119, of a pivoted half-nut 117, Figs. 6, 6A, carried by the carriage with a threaded shaft 109 driven by gearing 110, 112, from the shaft 51 connected to the motor 54 which effects rotation of the cylinder 23a in the scanning position. A small motor mounted in the carriage drives a light-chopper disc 108 located between the end of the pick-up tube 91 and the cell 92 to generate an appropriate carrier-frequency. An arm 191, Fig. 6, engaged by the solenoid 119 at the end of the downward travel of the carriage operates a switch 189 which controls the return of the carriage to its upper position and the energization of a magnet 199, Fig. 11, operating an arm 193 carrying a marker 197 to the position 193<SP>1</SP> shown in dotted lines to indicate that the copy 38 carried by the cylinder 23a has been scanned and transmitted. Circuit arrangements and general operation. At the transmitter station, Fig. 16, the operation of the selector switch 155 rotates the cam 159 to close contacts 165, 165<SP>1</SP> operating relay 204 which at contact 203 connects conductor A<SP>1</SP> to the terminal A of the supply A, B. This connection energizes the light-source 89, motor 105 driving the chopper disc and the motor 54 which rotates the driving pin 66 which is brought into driving engagement with the pin 67 of cylinder 23a by the operation of the solenoid 72. The interrupted current transmitted over lines L1, L2 is applied at the receiver station, Fig. 17, through a signal inverter 210 and amplifier 211 to the recorder 214, 215 and also to a relay 217 which is slow to release-and energizes a relay 219 which at contact 221 completes the circuit of the driving motor 225 of the receiver and at contact 222 applies a positive voltage to the line L1. At the transmitter, relay 230, operated to its contact M by the positive voltage on the line L1, energizes a relay 237 which closes contacts 238, 239 to energize the solenoid 119 operating the half-nut 117. Positive voltage is connected to the line L2 from a rectifier 242 over closed contact 246<SP>1</SP> of unoperated relay 245 and contact 241 of the relay 237, and at the receiver, Fig. 17, the positive voltage operates the armature 257 of a relay 256 to its contact M<SP>1</SP> energizing the blank-feeding and mounting mechanism BF of the recorder 214, 215, as described in U.S.A. Specification 2,386,263. Relay 260 is also operated and opens contact 264 which in conjunction with a device 266 prevents the stripping mechanism ST from operating at this stage. When the carriage CR has completed its downward movement the closure of contacts 189, 191 operates a relay 269 which at contact 271 operates relay 273 which energizes the solenoid 199 to actuate the marking device MK. At contact 253 the positive voltage over line L2 is removed. At the receiving station, relay 256 releases allowing the mechanism ST to operate to remove the recorded sheet and to energize relay 275 which at contact 276 applies negative voltage to the line L1. Relay 230, Fig. 16, is now operated to its contact S, opening the circuit of relay 237 which releases the solenoid 119 and frees the traversing shaft from the half-nut 117 so that the scanning carriage CR is returned upwardly to its starting position. Relay 280 operates, completes a circuit for the solenoid 172 operating the latch 166 to release the turntable for rotation and opens the circuit of the clutch magnet 72. At contact 285 a circuit is completed for the motor 39 driving the turntable 18 and a contact 183<SP>1</SP> closed during the engagement of the shaft 26 with the curved surface 188 of the pivoted lever 185 maintains the circuit of the motor until the shaft 26 of the succeeding cylinder engages the notch in the latch 166. At contact 283, relay 245 is operated and negative voltage from the rectifier 242 is fed over contact 247, contact 287 of operated relay 280, contact 241<SP>1</SP> of unoperated relay 237 to the line L2 operating relay 256 at the receiver to its spacing contact S<SP>1</SP>. Relay 279 now operates and at contact 278 restores the stripping mechanism to its normal condition and effects release of relay 275 which applies positive voltage over the line L1. At the transmitter the armature 231 of the relay 230 is moved to the contact M releasing relays 280, 245 and the associated solenoids and operating relay 237 which restores the system to the condition for transmitting the copy carried by the cylinder which has been moved to the scanning position. In a modified arrangement, Fig. 21, for supporting the copy 326 to be transmitted against the inner surface of the transparent scanning cylinder 310, a number of spring fingers 311 have inwardly directed bottom ends 315 held between a disc 313 and the base 312 of the cylinder and inwardly curved lower portions 324 engaged by a disc 320 with an appropriately curved outer surface end connected by a hollow sleeve 319 with an operating knob 321. The upward movement of the sleeve 319 on a supporting rod 317 allows the fingers to flex inwardly, as indicated at 311<SP>1</SP>, to facilitate the insertion of the copy 326. In a further modification, Figs. 22, 23 (not shown), four cylindrical sectors similar to the members 33, Fig. 5, have pins engaging in oversized holes in the base member of the scanning cylinder and a conical aperture formed at the centre of the four segments is engaged by a similarly shaped conical member supported for axial movement on a central rod to cam the sectors outwardly to hold the copy against the inner surface of the cylinder. The driving arrangement for rotating the drum and for the traversing movement of the scanning carriage may be employed with a transmitter employing a single drum, the selecting and control switch for the multi-cylinder arrangement being replaced by an on-off switch. The Specification as open to inspection under Sect. 91 includes a multi-cylinder scanning apparatus, Fig. 24 (Cancelled) (not shown), in which the matter to be transmitted is on sheets secured by garter springs on cylinders of metal or other opaqu