GB165554A - Improvements in and relating to visual mine signalling devices - Google Patents

Abstract

165,554. Ritchie, D. M., Ritchie, W., and Smith, J. April 8, 1920. Mechanical telegraphs; mine and colliery signals.-In mine signalling apparatus having a signalling pointer and a cautionary pointer carried round therewith, arrangement is made whereby the signalling pointer is returned to zero when the winding-engine moves, but the cautionary pointer is returned only when the engine has made a movement and stops. The signalling pointer is also zeroized by the first impulse of a succeeding signal, and signals given during the wind are cancelled when the engine stops. The signal pointer B mounted on a spindle provided with ratchet-wheel 3 has a projection 20 engaging and moving the cautionary pointer C which is mounted on a sleeve provided with a ratchetwheel 6. The ratchet-wheel 6 is engaged by a detent lever 12 pivoted at 14. The ratchet-wheel 3 is engaged by a detent lever 11 pivoted at 13. When a sliding rod D is raised by a signalling impulse, a cross-bar 17 raises a weighted rod 18 connected to the piston of a dash-pot 19. Rod 18 momentarily raises lever 11 allowing the signal pointer to return to zero under the action of a weight 9 and cord 7 passing round a pulley 2. On descent of the rod D, a pawl 16 engages and rotates the ratchet-wheel 3, a second pawl 15 limiting the movement to that of one tooth. A governor F, or a centrifugal pump or other device driven from the winding-engine, is arranged to lower a rod E when the engine is running, and raise it when the engine stops. Rod E carries projections 24, 29, the former raising the detent lever 11 as the rod descends, thus returning the signalling pointer to zero, the latter raising detent lever 12 as the rod rises, thus freeing the ratchet-wheel 6 and returning the cautionary pointer to zero under the action of a weight 10 and cord 8. The levers have pivoted end pieces 22, 27, 28 which move the levers in one direction only, but yield to the passage of the members 18, 24, 29 in the opposite direction. A lever 25 situated above the members 27, 28 is rocked when the detent lever 12 is raised as the engine stops, so that the lever 11 is also raised. Any signal given whilst the engine was running is thus cancelled.