Patent GB-127110-A (GB)
Title: Improvements in, or connected with Staff, or Token, Instruments for Controlling Railway Traffic.
Inventor: SMITH EDWARD WYTHE
IPC: B61L23/24
Filed: 1918-05-28
Abstract: 127,110. Smith, E. W. May 28, 1918. Staff, tablet, and ticket systems.-Staff or other token apparatus of the Webb and Thompson or similar type is provided with an improved form of lever and cam mechanism for controlling the commutator switch, with means for preventing the staff-controlling disks from overrunning their releasing positions, with means for clutching the commutator cam to either the staff-controlling disks for absolute working or to a ratchet-wheel for permissive working and for disconnecting the electric lock during permissive working, and with means for interlocking the instrument with the starting-signals by the use of a detachable key. The magazine is arranged to be detachable from the head and the frame or support of the machine, locks and keys being provided on both parts so that a staff or token cannot be passed through the communicating-openings unless the magazine is locked in place against the head. Fig. 5 shows one form of cam 3 against which bears a lever 7. The lever 7, as shown, bears against the lever 1 of the commutator switch, and, in other forms, is either pivoted or linked to the switch lever, so as to reverse the switch each time a staff is inserted or withdrawn. The cam 3 may be shaped so as to reverse the switch quickly at the beginning or the end of the movement, or to maintain the switch open during the movement. A limb 7<b> is fitted on the lever 7 to ensure resetting of the lever. The diameter of the cam 3 is less than the diameter of the base of the slots 6 in the disks 5. A disk 8, of larger diameter than the disks 5, serves to ensure that the disks 5 are stopped before the staff is moved radially. The disk 8 is held by a spring detent 8a. The cam 3 is connected by a feather 11 on the spindle 10 with either the disks 5 or a ratchet-wheel 12, 12<a> for absolute or permissive working respectively. The disk 12, Fig. 5, is controlled against backward rotation by a pawl 13. The disk 12<a>, Fig. 4, is controlled by a pawl 13<c> which is moved by a polarized electro-magnet 18 to permit motion in either direction as may be required. Before changing to permissive working, the spindle 10 must be pushed into the position shown in Fig. 4, and to permit this the bolt 16 must be lifted by a detachable key 15<a>, which also locks the starting- signal levers, which must be at danger before the key can be released for use in the instrument. This lock may also serve to break the circuit of the polarized lock-magnet 18. A pointer 19 on the spindle 10, in co-operation with a dial 20 on the disks 5, indicates the number of staffs issued. In order to provide for the transport of a number of staffs from one station to another in cases where traffic is greater in one direction than another, the magazines are detachable from the head and stand of the instrument, and more than one magazine is provided for each instrument. The upper part of a magazine, Fig. 22, is adapted to fit the upper part of the pedestal, Fig. 19, on which the head is supported, and the communicating-passages through which the staffs are passed are provided with bolts 24, 26 which, when shot, close these passages. These bolts are controlled by keys 28, 29 permanently attached to the other member, and can thus only be retracted when the .magazine is in place in the instrument pedestal, and, when so retracted to permit the passage of staffs, they serve to lock the magazine in position. The magazine and the associated parts of the head and stand are so shaped that staffs or tokens belonging to one section cannot be passed into the instrument of another section of track. One support may carry two instruments, and the instruments mav be arranged for double-track working.