GB371128A - Improvements relating to relay mechanisms for controlling fireextinguishing apparatus - Google Patents

Abstract

371,128. Automatic release hooks. PYRENE CO., Ltd. and HUNTER, J. N., Great West Road, Brentford, Middlesex. March 18, 1931; No. 8330. [Class 89 (ii).] Relates to relay mechanism for releasing suspended weights or stressed springs for operating fire - extinguishing apparatus, and particularly applicable to the automatic or distant control of such apparatus; and comprises a train of pivoted, interlocking levers normally held from turning movements by a spring-loaded ratchet and pawl. The lever 2 at one end of the train of levers 2, 12, 10 is formed with a hook 1 to support the weight (not shown). The lever 10 is held from turning movement about its pivot under action of a spring 21 by means of an arm 9 normally lying at right angles to the lever 10 and carried by a gear wheel 8. The latter is urged to rotate, to free the lever 10, by a spring 20, but is held from rotation by its engagement with a pinion 7 fast with a ratchet wheel 6, the latter being locked by a pawl 4. When the pawl is disengaged, the spring 20 is free to move the arm 9, but the arrangement is such that the pawl may slip several teeth of the ratchet accidentally without causing release of the weight. The lever 12 exerts its locking thrust on the lever 10 in the direction of the pivot of the latter, so that the force due to the weight is not transmitted to the ratchet. The impulse for disengaging the pawl from the ratchet is derived from air bulbs placed in an area to be protected. In case of fire, the air expands, and moves a diaphragm 14 carrying a pin 19 in engagement with the tail of the pawl. Alternatively, the pawl may be disengaged by manual or electrical means. In a modification, the pawl is disengaged by a lever which is moved by a spring when released by the movement of an impact-operated pendulum.