Patent GB-310304-A (GB)
Title: Improvements in electrically operated and controlled means for operating the barriers at railway crossings
IPC: B61L29/22
Filed: 1928-01-23
Abstract: 310,304. Westfelt, A. U. Jan. 23, 1928. Operating barriers electrically.-In electrical operating and controlling means for the barriers of railway crossings in which the barrier bars are operated by motors under the control of a combined switch and its actuating device and a current controller, the current controller comprises circuits to actuate the switch in alternate directions, the circuits being under the control of a relay device which is so arranged that, when the train moves away from the road crossing, the circuit for the actuation of the motor in a direction corresponding to the lowering of the barrier bars is interrupted earlier than the circuit for the actuation of the motor in the direction for lifting the barrier bars. The relay device and part of the track are represented in Fig. 1, the switch and its change-over device in Fig. 2, the general arrangement of the track and the gate operating devices being shown in Fig. 3. The railway track is divided into a series of insulated sections 2, 3, 4, of which the end rail sections 2, 3 are connected by cables 5, 6 respectively, the sections 2, 3, 4 of the line 1 being connected to the positive poles of the batteries 25, 33 and 26 respectively, as shown in Figs. 1 and 3. The switches of the relay device, shown in Fig. 1, control the current to the motor 35, Fig. 2, that operates the barriers and the disc 36, this disc serving to set a switch lever 45 for the subsequent movement of the barriers. The positive pole of the. battery 23 is connected to contacts 16<a>, 19<a> and its negative pole to contacts 17<a>, 18<a> of a pivotally mounted bar 8; the battery is earthed to the track line 1<a>. The contacts of the bar 8 are adapted to be brought into circuit with terminals 29 - - 32 leading to contact members 48 - - 55, pairs of contacts of which are adapted to be engaged by a movable switch lever 42. This lever is movable by a lever 39 that is adapted to be thrown over by one or other of the pins 37, 38 of the oscillatory disc 36, driven by the motor or motors 35. The latter lift and lower the barriers 67, Fig. 3, across the roadway. When the train reaches the rail section 3, the battery 33 is short-circuited by the wheels bridging the section 3 and the rail line 1<a>, the electromagnets 10, 11, 12, Fig. 1, are de-energized, and the right-end of the lever 7 falls down so that the pins 14a, 15<a> make contact with the mercury in the glass cups 14, 15. Current then flows from the battery 23 through bar 8 to contacts 16a, 16, contacts 14a, 14, and a terminal 29 that is connected to contact 50 of the switch 60, Fig. 2. and back through the contact 51 and terminal 30, contacts 15, 15a 17, 17<a> and 18a to the negative pole of the battery 23, the switch lever 42 being positioned to the left-hand side to make contact with the contacts 50, 51. Current then flows through the motor to drive it in a direction to unwind the cable from the drum and lower the barriers across the roadway. At the same time the wheel 36 is rotated anti-clockwise and the pin 37 moves the arm 65 to the left until the pin 40 causes the contact arm 42 to move to the right, causing the motor to stop. Prior to this. the current flowing through the contacts 52 - - 55 was broken in the mercury cups 18, 19. When the first pair of wheels of the train makes contact with the insulated rail section 4, positioned at the barriers, the magnet 11<a> attracting the pawl 22, Fig. 1, is short-circuited, causing the pawl to leave the pin 8<a> and engage underneath the pin 8<b>. As the train leaves the section 4, the coil 11<a> is de-energized and the weighted pawl 22 swings out of engagement with the pin 8<b> and releases the arm 8, which falls towards the mercury cups 18, 19 and completes 1 a circuit through the contact pins 18a, 19<a>. Current from the battery 23 then flows through the contacts 52, 53 of the switch 60 and terminals 31, 32. The motor is then operated to wind up the cable and lift the barriers, the current being interrupted by the operation of the disc 36 and arm 42, as before. The current for lowering the bars is interrupted in the cups 16, 17, and the arms on the right of the levers 7, 8 are in the lowered position. As the train finally reaches the remote rail section 2, the current for the magnet 12 is again short-circuited through the battery 25, the arm 9, 9<a> being then attracted so that the pins 20<a>, 21a make contact with the mercury cups 20, 21. The magnets 10, 11 then receive current through their respective batteries and attract the levers 7, 8 to return them into their initial positions. The magnet 12 becomes deenergized when the train leaves the rail section 2, the magnets 10, 11 being thereby deenergized, and the lever 7 is kept attracted by the current from the battery 33. The lever 8 is retained in a position of rest through its pawl 22 engaging the pin 8<a>, the arrangement being thus re-set for a further sequence of operations by a train approaching from either direction. The arm 9, 9<a> with its pins 20<a>, 21<a> and the mercury cups 20, 21 are so constructed that the pin 20<a>, on the attraction of the arm, makes contact with the mercury in the cup 20 a moment before the pin 21<a> makes contact with the mercury cup 21, when the train restores the relays to the idle position. This causes the attraction of the lever 7 prior to that of the lever 8, and provides against an electric current passing through the motor for lowering the bars as the train moves away from the railway crossing.