Patent GB-650536-A (GB)
Title: Apparatus for controlling mechanism such as sorting, counting, tabulating or calculating mechanism
IPC: G06V30/224
Filed: 1947-07-30
Abstract: 650,536. Electric selective signaling. CROSFIELD, J. F. July 30, 1947, No. 20665. [Class 40 (i)] [Also in Groups XIX and XL (b)] In a machine for sorting objects by means of symbols on them, the symbols are each provided with a datum line and other lines spaced from it at predetermined intervals and parallel to the datum line, the sorting mechanism being operated by differentiated output pulses from a scanning mechanism produced only by such lines and not by others lying in different directions. Examples of such symbols are shown in Fig. 1, the datum line being at O and the parallel lines at A-E. The description is with reference to their utilization in a cheque sorting machine in which the scanning is accomplished photo-electrically. It is stated that instead of photoelectric scanning the lines may be printed with a metal-containing ink forming a condenser with a metal wire parallel to the line or this wire may be excited with alternating current so that a line or edge parallel to it causes a change in the magnetic field. Producing and registering code signals by scanning. The cheques are fed between plates (Fig. 3) by continuously-driven rollers 1 so that the symbol passes under a slot 3a. Light from a source (not shown) mounted above the slot is reflected to a photo-cell 7 so that as the datum line and the parallel lines successively fill the slot the light incident on photo-cell 7 is suddenly varied. Evenly-spaced key marks K are provided beside the symbols and are examined before the main symbol in a smaller slot by a photo-cell 6. The signals obtained from photo-cell 7 are applied to differentiating circuits 13, 14, R1, Fig. 5, to produce an impulse at the grid of pentode tube 15 when the light affecting the cell changes sufficiently suddenly as with the lines or edges parallel to the datum line but not with lines or edges in other directions. Tube 15 normally has a paralysing bias on its suppressor grid but this is neutralized an instant before the numeral is scanned, provided that the cheque is correctly aligned and is travelling at the proper speed by a signal from the photo-tube 6, and its tuned anode amplifier 10, due to the regularly-spaced key marks K. This effect persists for the time necessary to scan the numeral. The code signal impulses from 15 are passed to the first of a pair of flipflop circuits 16, 17 which, with the aid of a delay network 18 and a group of flip-flop tubes 21-25 act as a distributer to render magnets 31-35 operable in turn. The code signal impulses are also passed to flip-flop circuits 19, 20 which have one stable condition in which the lefthand triode conducts. Rectifiers suppress the positive impulse produced when the image at the slit suddenly changes from dark to light. Circuit 20 operates magnet 30 when the datum line is scanned and remains off normal long enough for the completion of the sorting of the cheque concerned. Circuit 19 quickly returns to its stable condition and so repeats the code impulses (with change of sign) to the left-hand grids of all the distributer tubes 21-25 to cause the operation of one or more of the magnets 31-35 in accordance with the position in the distributer cycle in which signal impulses are received. The relays remain operated long enough for the sorting operation to be completed. In modified systems different distributer circuits are used. Sorting in accordance with registered signal. The cheques are fed by rollers 1, Fig. 6, between a particular pair in a pile of leaf springs to a receptacle 46. The pair is selected by the position of the upper ends of constantly reciprocated rods, one of which can be seen (28b), which in accordance with that position engage tongues at the end of a particular spring and so separate the pile at a particular level. The positions of the ends of the rods are determined by the positions of slots 39a, 40a, and 39b, 40b, Fig. 7, in members 39, 40, which in each sorting cycle are moved in directions at right angles against springs 41, 42 by constantly driven cams 37, 38, and then allowed to return to a position determined by the condition of magnets 30-45. If magnet 30 is not operated, because the apparatus is not working properly, the reciprocating rods miss all the springs and the cheque passes to a special bin. Distributer circuits. In the arrangement shown in Fig. 5 the negative portion of the signal when the cell 7 scans the datum line is passed on to a flip-flop tube 16 with one stable condition in which the left-hand triode conducts. The resulting change to the other condition is without effect but after a time sufficient for the first code mark to be reached the tube returns to its stable condition and the resulting impulse is passed on to a similar flip-flop circuit which changes over to send a negative impulse into a delay line 18 and then returns to generate a positive impulse. By means of couplings to different parts of the delay line, flip-flop circuits 21-25 are prepared for operation in turn. In a modification, Fig. 10 (not shown), operation is the same except that the delay line is replaced by valve circuits. Operation of a multivibrator instead of charging a delay line, causes a " Phantastron " circuit of the type described in I.E.E. Journal, Vol. 93, Part IIIA, No. 1, at pages 320-321, and in No. 7 of the same volume, at pages 1193 to 1197, to give a linearly increasing voltage to a number of " Multiar " circuits described in the same Journal, these circuits operating in succession to apply negative potential to the grids of the relay operating " flip-flops " as did the delay line in Fig. 5. In a further modification (Fig. 11, not shown), a circuit is employed making use of a ring counter as described in Specification 572,884, [Group XL]. To use this circuit the evenly-spaced key marks must be replaced by marks positioned identically with marks O, A, B, C, D and E. Successive marks operate photo-cell 6 to cause the left-hand half of valve 204 to block and the right hand to conduct at the same time applying a negative pulse to the grid of a relay-operating multivibrator. The next pulse restores the first valve'of the counter to its original condition and reverses the second which then conditions a second relay operating multivibrator. The second pulse necessary to operate the relays is supplied by the marks on the symbols themselves.