GB191405395A - Improvements in Signal Indicators or Registers such as are used in Collieries. - Google Patents

Abstract

5395. Stoddart, H. March 3. Bell signals; mechanical telegraphs.-A signal indicator or register for collieries is operated by impulses transmitted from a distance through a wire in such a manner that the first impulse returns the indicating-arm to its zero position and afterwards moves it one step, while succeeding quickly-applied impulses move the arm step by step, during which time the releasing-mechanism is inoperative. The indicating-arm 20 is mounted on a spindle 19 which is keyed to a spring-restrained ratchet-wheel 16 adapted to be operated by means of a pawl 15 mounted on a reciprocating rod 1 which carries also a roller 27 and a pin 9. The arm 20 is held in any one of its operative positions by means of a detent mounted on a spring-controlled lever 25 provided with a notch 24 which is adapted to be engaged by a weighted pawl 23 mounted on a lever 7. One arm of the lever 7 carries a weight 8, a second arm is in the form of a cam-surface 6, while a third arm is connected to the movable element of a dash-pot 22. The wire transmitting the impulses is attached to the upper part of the rod 1 and passes over a pulley. If the arm 20 is in one of its operative positions and an impulse is transmitted through the wire, the roller 27 by engaging the cam-surface 6 raises the weight 8 and lowers the pawl 23 and notch 24 against the action of the spring 26, thereby withdrawing the detent from the ratchet-wheel 16 and allowing the arm 20 to return to its zero position. When the rod 1 is allowed to fall, the pin 9 engages a notch 10 and lifts the hammer 12 from a gong 13; while a further movement of the rod releases the hammer 12 and causes the pawl 15 to engage the ratchet-wheel 16, thereby moving the arm 20 to its first operative position. If the gong is to be struck more than once and the arm 20 to be operated a corresponding number of times, impulses must be transmitted through the wire in quick succession in order that the pawl 23 may not engage the notch 24. The pawl 15 is inclined to clear the ratchetwheel on its up-stroke by causing a tail-piece 28 to engage a stop 30 at the end of the down-stroke of the rod 1, and to engage a stop 29 at the end of its up-stroke to place the pawl in its operative position. The arm 20 may be released by hand by allowing the lever 25 to project through the casing.