Patent GB-823321-A (GB)
Title: Improvements in or relating to counting mechanisms for axle counting arrangements
IPC: B61L1/16
Filed: 1957-09-03
Abstract: 823,321. Counting-apparatus. SIEMENS & HALSKE A.G. Sept. 3, 1957 [Sept. 3, 1956], No. 27843/57. Class 106 (1). In an electrical pulse counter for axle counting arrangements incorporating sequentially arranged counting members, during the first counting step succeeding the initial position, each of the counting members should change its state, and the operation of a supervisory device is dependent on the state of the counting members after this step. In the counting arrangements described, counting-in and couning-out pulses due to railway axles entering and leaving a track section, are applied to inputs EE, AE respectively. As shown in Fig. 2, such pulses are applied to separate binary counters comprising transistor bistable flip-flop circuits 10, 20, 30 and 18, 28, 38. In the initial position, each flip-flop registers " 1 ". Thus the first counting-in pulse will cause all the circuits 10, 20, 30 to return to " 0 ". whereupon flip-flop 46 is switched over through coincidence gate 40; this provides a check on the correct opertion of the counting circuits. The circuits 10, 20, 30 will then be stepped in normal binary fashion to register the number of axles which have entered. The circuits 18, 28, 38 operate similarly when the axles leaves the section, the first counting-out pulse switching over flipflop 48. When the counters register the same number, a coincidence testing circuit comprising gates 12, 14, 22, 24, 32, 34 and " or " gates 16, 26, 36 energizes gate 42. The three inputs to test gate 49 are then operative, so that a " track clear " potential appears at output F. This causes the resetting of the flip-flop circuits by positive potentials at terminals R followed by a test to ensure that all these circuits have returned to the normal position, before the track section is cleared. In another arrangement, Fig. 3, a single counter comprising flip-flops 50, 60, 70 is stepped forward for counting-in and backwards for counting-cut through magnetic core coupling circuits 54, 64 and 56, 66 respectively. A counting-in pulse at EE will switch monostable flip-flop 72, whereby it applies a temporary bias to windings 542, 642, which bias added to the current applied to 541 or 641 when flip-flop 50 or 60 is switched from " 1 " to " 0," is sufficient to change over the core of 54 or 56 so as to apply a pulse via winding 543, 643 to the next flip-flop 60 or 70, an output from 72 being applied also to the first flip-flop 50. The counting-out pulses similarly cause monostable flip-flop 74 to apply bias to winding 562, 662 whereupon flip-flops 60, 70 are actuated each time the preceding flip-flop is switched from " 0 " to " 1 ". The counter should finally return to the normal position whereupon, provided that flip-flop 78 (corresponding to 46, Fig. 2) has been switched via gate 76 in response to the first counting-in pulse, gate 80 will then emit the " track clear " potential at output F. The testing arrangement comprising multiinput gates 76, 80 may be replaced by an additional flip-flop counting stage, a further flip-flop and a gate needing only two inputs (Fig. 4, not shown). A detailed circuit diagram is given for the transistor flip-flop circuits of Fig. 3. Reference is made to the use of non- binary counting members, e.g. rotary selectors or relay chains.