GB191419388A - Improvements in Signalling Devices for use in Mines. - Google Patents

Abstract

19,388. Lochhead, W. March 3, 1915, Mechanical telegraphs; bell signals. -Relates to signalling-apparatus for mines, of the kind in which a continuous series of impulses steps a pointer round a dial, while the first impulse after a pause returns the pointer to zero and then advances it to the position "1," and consists in providing a semaphore having a cautionary indication, for example " Men," and a zero indication, the "Men "indication being brought into a visible position when a certain number of impulses, for example three, are given. The pointer is attached to a shaft 4 carrying a ratchet-wheel 3<a> engaged by an operating pawl 3 and a locking-pawl 7<a>. The operating-pawl 3 is formed on a weighted rod 5 arranged to slide vertically in a frame 18 capable of slight rocking movement on a pivot 19. The locking-pawl 7<a> is pivoted on a pin 7<b> and is weighted so as to tend to engage the teeth 3<a>. A bent rod 8<a>, attached to a weighted rod 8 carrying a piston working in the dash-pot cylinder 9<a>, disengages the pawl 7<a> when in its lowest position. When a signal is given, the rod 5 is raised and by means of a projecting pin 9 lifts the rod 8, thereby allowing the locking-pawl 7<a> to engage. The rod 5 then falls, and its pawl 3 rotates the ratchet-wheel through an angle equivalent to one tooth. The descent of the arm 8<a> is delayed by the dash-pot, and so long as the signal impulses follow in quick succession, the pointer spindle 4 is rotated through an angle corresponding to the number of impulses. After the final impulse, the rod 8<a> slowly descends and disengages the pawl 7<a>. On lifting the rod 5 to give the first impulse of a later signal, the pointer is returned to zero position by a weight 7, and is then stepped forward to the position " 1 " by the downward movement of the rod 5. A bent rod attached to the swinging frame 18 co-operates with a shoulder on the tail of the pawl 7". In order to enable composite signals to be given, for example when men are to be carried, the zero space on the dial is cut away, and a semaphore 11, Fig. 4, pivoted on a pin 12 is arranged to display the indication " Zero " or " Men " in the slot so formed. A pawl 14 on the semaphore 11 is engaged by an arm 13 on the pointer spindle when the pointer reaches the third space on the dial, thereby swinging over the semaphore and displaying the indication "Men.'' If a fourth impulse immediately follows, the arm 13 engages a curved surface 17 on a hanging arm and causes a tail-piece 15 thereon to engage a shoulder 14<a> on the semaphore and return it to its normal position. If, however, a pause follows the third impulse, and subsequently one or more further rings are given, the "Men" indication remains visible, while the pointer first returns to zero and is then stepped forward therefrom according to the number of further rings. The semaphore is returned to normal position by a connexion to the winding-engine, when this is started.