GB1564316A - Fire extinguisher operating head - Google Patents

Description

(54) FIRE EXTINGUISHER OPERATING HEAD (71) We, NIMROD FIRE PROTECTION LIMITED, a British Company, of 4 Depleach Road, Cheadle, Cheshire, formerly of 198 Queensway, Heald Green, Cheadle, Cheshire SK8 3HH, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a fire extinguisher operating mechanism for a fire extinguisher.

The present invention provides a fire extinguisher operating head including a detonator capable of causing rupture of a frangible cap or piercing of a diaphragm of the extinguisher, characterised in that the detonator comprises a protractor which is accommodated in a housing which is detachable, as a unit incorporating the protractor, from the rest of the head, a carriage being mounted in the head so as to be displaceable by a piston rod of the protractor, upon actuation thereof, to engage and rupture the frangible cap or to pierce the diaphragm.

The carriage may have a portion which serves after actuation of the protractor, e.g. by projecting from the head or by operating electrical contacts, to provide an indication that the extinguisher head has been actuated.

The housing preferably comprises a cylindrical body, and a plug which is screwed into one end of the body and which also mounts the protractor, for example by the latter being screwed into the plug the other end of the cylinderical body mounting an electrical socket connected to the protractor.

The invention will be described further, by way of example, with reference to the accompanying drawing, wherein the single figure is a cross-sectional view illustrating a preferred embodiment of the fire extinguisher operating head of the invention fitted to a fire extinguisher.

As shown, a first extinguisher 10 comprises a container 11 for a fire extinguisher liquid (not shown), which container 11 has an externally threaded upper spigot 12 terminating in a frangible cap 14 adapted to rupture, upon movement, along a line 15.

A preferred embodiment of head 16 of the invention comprises a shroud 17 screwed onto the spigot 12 and sealed relative thereto by an O-ring 18.

Into a radial hole in the shroud 17 fits an end of a cylindrical guide 19 whose other end has a central aperture 20 for a purpose to be later described. A carriage 21 is sealingly slidable in the guide 19 and has a transverse slot 22 into which the frangible cap 14 projects. One end of the carriage 21 faces a denotor unit 23 (to be later described) and the other end has an extension 24 which, when the head has been actuated, and the carriage 21 has been displaced to the left in the figure, projects through the aperture 20 and either by so projecting, or by closing electrical contacts (not shown), provides an indication that the head has been actuated. A handle or cable 31 may be connected to the carriage 21 by way of the projection 24 to allow manual actuation of the operating head for example by displacement or rotation of the carriage 21.

The detonator unit 23 comprises a housing including a plug 25 screwed into an aperture in the shroud 17 in co-axial alignment with the guide 19. A protractor 26 is screwed into the plug 25 with a piston rod (not visible) thereof facing the confronting end of the carriage 21. One end of a cylindrical body 27 of the housing has the plug 25 engaged therein and the other end thereof mounts a socket 28 to which wires 29 from the protractor 26 extend. An electrical plug 30 can engage the socket 28 to make electrical contact therewith.

Upon an electrical signal being supplied through the wires 29, a small explosive