GB2050159A - Head mounting for pressure container - Google Patents

Abstract

A discharge head, for example including a discharge spout, handle and operating lever of a portable stored pressure fire extinguisher, mounted on a pressure container, 10, having a neck formation defining a recess or opening of which the cross-section at the mouth thereof is less than the cross-section inwards of the mouth, comprises a body member 5, a retaining formation 7 including a resiliently deformable skirt portion adapted to fit into the mouth, and extend therethrough into the inward portion of the recess or opening, an expander element 6 having a tapered portion engaging the end of the skirt and screw means operable to draw the tapered portion into the skirt for radial expansion thereof into clamping engagement with the recess or opening. <IMAGE>

Description

SPECIFICATION Head mounting for pressure container This invention relates to the mounting of a discharge head onto a pressure container, particularly but not exciusively in a portable or other fire extinguisher; enabling a head as sembly, for example formed from moulded plastics components, to be readily and securely assembled, for example onto a previously charged and sealed metal container provided with a discharge valve, the head including means for actuating said valve.

According to the invention there is provided a discharge head for mounting on a pressure container of the kind having a neck formation defining a recess or opening of which the cross section at the mouth thereof is less than the cross section inwards of said mouth, comprising a body member, a retaining formation including a resiliently deformable skirt portion adapted to fit into said mouth and extend therethrough into the inward portion of the recess or opening, an expander element having a tapered portion engaging the end of the skirt and capable of passing through the mouth when so engaged, and screw means operable to draw said tapered portion into said skirt for radial expansion of the latter into clamping engagement with the recess or opening to attach the body member to the neck formation.

One embodiment of the invention is now described by way of example with reference to the accompanying drawing being a longitudinal cross-section of the upper portion of a portable stored pressure dry powder fire extin gusher.

The extinguisher comprises a metal pressure container 10 whose upper end terminates at a reduced-diameter neck 2 having a beaded edge onto which is crimped or rolled a metal closure 3. Closure 3 has an inwardly recessed central area in which is mounted a central discharge valve assembly 1 3 of conventional construction, actuated by inward displacement of a plunger thereof. The wall of closure 3 is belled radially outwards so that it engages below the edge of neck 2 to resist outward pressure, thus providing an increased diameter part of the closure recess immediately below the mouth defined at its junction with neck 2.

The extinguisher also includes a discharge head which is mounted on container 10 after it has been filled and pressure charged; i.e.

after closure 3 has been applied along with valve assembly 1 3. The head has a moulded plastics main body member 5 including a loop handle 4 through which a user's finger can be engaged, and an annular seating formation sixed to fit closely around the exterior of neck 2 against or near to the adjacent shoulder part of container 1 0. A threaded bore is provided co-axial with the seating formation and accessible through the top of body member 5 prior to assembly of other components of the head referred to hereafter.

A retaining formation consists of a collar 7 formed from resiliently deformable plastics material, e.g. polyethylene, having a top flange which is a push fit in the seating formation of member 5 for abutment with the top of neck 2 and a downwardly depending annular skirt portion closely fitting said neck and extending into the increased diameter part of the closure recess when engaged therewith. The skirt portion is slotted axially so that it is divided into a plurality (e.g. eight) axially extending finger portions.

An expander screw 6, also a plastics moulding, has an externally threaded stem for screw engagement with the threaded bore of body member 5 and a frusto-conical end portion which diverges from the stem to engage the end of the skirt portion of collar 7 when assembled. Screw 6 has a co-axial through bore of hexagonal cross section for engagement by an "allen key" or like tool inserted from the top of the head.

On assembly the body member 5 carrying collar 7 and screw 6 is pushed axially onto the neck of container 10, then screw 6 is rotated to draw its conical end portion into the skirt portion of collar 7 so as to expand the finger portions of the latter radially outwards into clamping engagement with the increased diameter inner part of the closure recess thus drawing the body member 5 tightly downwards onto neck 2.

An L shaped moulded plastics discharge spout 9 is next passed through the aperture in screw 6 to co-act with discharge valve assembly 1 3 both to provide an outlet passage therefrom through the head and also form a plunger which can be pressed downwards to actuate the valve. Finally a plastics actuating lever 1 2 is located above spout 9 by springing upwardly extending parallel side cheeks of body member 5 apart sufficiently for snap engagement with integral pivot spigots on lever 12, a cam formation of the latter bearing on the top of spout 9 and an arm of lever 1 2 extending away from its spigots above loop handle 4 for convenient actuation by a user's thumb.

A removable plastics safety clip 8 is also provided which is a spring fit onto the lever arm to prevent inadvertent discharge.

In the above construction it is not necessary that a fluid tight seal be provided between head 5 and container 10 as the joint therebetween is outside the closure and valve seal.

However, in some constructions it is possible that the head itself might form the closure for the container, e.g. by collar 7 or part of body member 5 forming or being provided with appropriate sealing gaskets or rings to mate with the container neck or opening. In this case closure 3 might be omitted, the valve assembly would be carried by or in the head assembly itself, and the skirt portion of collar 7 would be expanded in the interior of the container directly below the rim or edge of the neck opening.

The retaining formation may take the form of a skirt portion integral with the body member instead of using the separate collar 7. The screw means may take various forms, for example instead of expander screw 6 being in direct threaded engagement with body member 5 it may be in threaded engagement with the central bore of a separate skirted retaining formation to clamp an interior flange of the body portion axially between an increased diameter head of said formation and the top of neck 2.

The invention provides a discharge head mounting which is readily and securely assembled onto a container without requiring access to the container interior or special mounting apertures or threaded bosses on the container itself, and which can be removed without damage if necessary e.g. to check the discharge valve, for testing, or possibly for recharging the container.

If gross excessive pressure should build up in the container 10 the arrangement described ensures that the discharge head does not become detached; instead the pressure will cause the metal closure 3 to concertina axially and the resulting radially inward deformation of the lower part of the recess wall will engage the end portion of screw 6 from beneath, increasing the security of the head.

As the container itself is the strongest, discharge through the head will take place before any bursting occurs.

Claims (11)

1. A discharge head for mounting on a pressure container of the kind having a neck formation defining a recess or opening of which the cross section at the mouth thereof is less than the cross section inwards of said mouth, comprising a body member, a retaining formation including a resiliently deformable skirt portion adapted to fit into said mouth and extend therethrough into the inward portion of the recess or opening, an expander element having a tapered portion engaging the end of the skirt and capable of passing through the mouth when so engaged, and screw means operable to draw said tapered portion into said skirt for radial expansion of the latter into clamping engagement with the recess or opening to attach the body member to the neck formation.

2. A head as in Claim 1 wherein the expander element includes integral screw means in threaded engagement with another component of the head and accessible for rotation from the exterior of the body member during assembly.

3. A head as in Claim 2 wherein said screw means is in threaded engagement with a bore of the body member.

4. A head as in Claim 1, 2 or 3 wherein the retaining formation is a collar including a flange for abutment with the exterior of the neck formation.

5. A head as in Claim 1, 2 or 3 wherein the retaining formation is integral with the body member.

6. A head as in Claim 2 wherein the retaining formation is a collar having a bore within which said integral screw means engages, said collar also including an increased diameter head and the body member including an interior flange which is clamped axially between said head and the neck formation on assembly.

7. A head as in any one of the preceding claims wherein the skirt portion is formed from resiliently deformable plastics material.

8. A head as in any one of the preceding claims wherein the skirt portion is slotted axially so that it is divided into a plurality of finger portions.

9. A head as in any one of the preceding claims wherein the expander element has a central through bore to accommodate a discharge spout and/or valve actuating plunger.

10. A discharge head for a pressure container substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

11. A fire extinguisher including a discharge head as in any one of the preceding claims.