GB2082151A

GB2082151A - Tamperproof cap for a keg spear

Info

Publication number: GB2082151A
Application number: GB802923A
Authority: GB
Original assignee: Mardon Illingworth Ltd
Current assignee: Impress Sutton Ltd
Priority date: 1980-08-19
Filing date: 1980-08-19
Publication date: 1982-03-03

Abstract

The cap has a skirt (12) having internal projections (14), which snap under a shoulder of a keg spear to hold the cap on the spear. The skirt has a tapering portion (25) extending beyond the projections. The material of the cap is such that there is sufficient resilience for snap-engagement on the spear, but the tapering portion (25) of the skirt is sufficiently brittle to prevent removal of the cap without damage. It is possible to grip the skirt with a tool to turn the cap together with the spear to unscrew the latter. This cannot be done without damage to fracturable projections (20) around the outer periphery of the skirt. <IMAGE>

Description

SPECIFICATION Tamperproof cap for a keg spear This invention is concerned with a tamperproof cap for mounting on a keg spear.

A keg spear is a device which is screw-engaged in an opening in the top of a keg for holding beer or the like. The device incorporates a plunger-operated valve, which can be actuated for tapping of the contents. The device can be unscrewed from the opening for access to the contents, for cleaning of the interior of the keg, or for replacement. The plunger is located in a recess in the top of the spear and surrounded by a non-circular surface, grippable by a tool for unscrewing the spear.

There exists a problem of kegs being tampered with and contents being removed. Beer, for example, may be watered to conceal tampering. Thermoplastic caps have been provided, which snap engage over the top of the sphere. Such a cap has a skirt provided with an internal flange which engages under a shoulder on the spear, so that the cap covers the recess and prevents access to the plunger and also covers the non-circular surface. The cap may be rotatable on the spear. Such a cap can usually be removed, with care, by distorting the cap, and replaced after the keg has been tampered with to conceal the fact. Where this is not possible without damaging the cap, it is possible to unscrew the spear using a cloth to avoid marking the cap, the cap skirt being sufficiently deformable for the spear to be so gripped, using a tool.

The present invention provides a tamperproof cap for a keg spear, the cap having a skirt provided with internal projection means for snap-engaging under a shoulder on the spear, the extreme outer periphery of the skirt being defined by a readily fracturable edge, this edge being the only part of the skirt grippable by a tool for turning the cap, the material of the cap being sufficiently resilient to permit said snap engagement, but sufficiently brittle for the cap to be damaged on removal and for said fracturable edge to be damaged when gripped by a tool for unscrewing the spear.

The material may be, for example, polystyrene with an impact additive or a.b.s.

The invention also resides in an injection-moulded tamperproof cap for a keg spear, the cap having a skirt provided with spaced projections around its inner periphery and the top of the cap having mould-finger-apertures aligned with the projections, the projections being snap-engageable under a shoulder of the spear, the extreme outer periphery of the skirt being defined by a readilyfracturable edge, this edge being the only part of the skirt grippable by a tool for turning the cap, the material of the cap being sufficiently resilient to permit said snap engagement, but sufficiently brittle for the cap to be damaged on removal and for said fracturable edge to be damaged when gripped by a tool for unscrewing the spear.

The outer periphery preferably slopes to a sharp edge and the edge is preferably defined by a multiplicity of fracturable outwardly projecting teeth.

Also preferably, the internal projection means, or the inner peripheral spaced projections, have a bevelled underface angled with respect to the top face to serve as a lead-in face to facilitate engagement over said shoulder.

It is also advantageous for the skirt to extend beyond the projections in the direction away from the top of the cap and for this projecting portion of the skirt to be readily fracturable, for example by tapering to a sharp edge. This will ensure that the skirt will fracture if a tool is used to grip the cap between the top thereof and the projections for unscrewing of the keg spear.

It is also preferred that means is provided to facilitate legitimate removal of the cap. A projecting tab may be provided on the skirt and the latter provided with lines of weakness to facilitate splitting of the skirt by pulling on the tab.

The invention may reside in a keg, fitted with a keg spear, in turn fitted with a cap as defined above, such that the keg spear cannot be unscrewed with damaging said fracturable edge and cannot be forcibly removed from the spear without damage.

Reference is now made to the accompanying drawings, wherein: Figure 1 is an underside plan view of a cap according to the invention; Figure 2 is a sectional view thereof on the line ll-ll of Figure 1; Figure 3 is a sectional view on the line Ill-Ill of Figure 1 showing the structure of a tab thereof; Figure 4 is an elevation of the tab and adjacent parts of the cap; Figure 5 is a sectional view similar to Figure 2 of a modified cap; Figure 6 is a sectional view similar to Figure 3 of the modified cap; and Figure 7 is an elevation similar to Figure 4 of the modified cap.

Referring to Figures 1 and 2, the cap shown has a top 11 and skirt 12. A peripheral portion 13 of the top is sloped relative to the remainder at 25 to shape the cap complementarily to the keg spear (not shown) with which the cap is to be used. This particular spear has a regular eleven sided periphery to facilitate gripping by a tool for unscrewing the spear from a keg. The skirt of the cap is closely fitted about this periphery in use, but is designed to rotate on the spear.

The skirt has an inturned flange spaced from the free end of the skirt. This flange is defined by a multiplicity of equi-spaced projections 14 and these snap-engage under a shoulder on the periphery of spear, when the cap is pushed onto the spear. The top 15 of each projection 14 is parallel to the top 11 of the cap, whereas the underface 16 is bevelled relative thereto to provide a lead-in to facilitate snap-engagement over the shoulder. The inner radial extent of the projections 14 and the brittleness of the material of the cap are controlled such that there is sufficient flexibility for engagement of the cap on the spear, but insufficient flexibility for the cap to be removed again without shattering of the cap.

To permit this facility, the cap is injection moulded and the top 11 of the cap has spaced apertures 18 aligned with the projections, these apertures being defined by mould fingers during the moulding process. Opposed mould fingers define the apertures 19 between the projecions 14. The material used may be polystyrene with impact additive to reduce brittleness sufficiently for the function described above.

The outer periphery of the skirt 12 is defined by a multiplicity of radially outwardly projecting teeth 20 spaced around the skirt. These teeth are triangular in section to define upper and lower surfaces 21,22 sloped relative to the plane of the top 11. The only grippable part of the outer periphery of the cap is therefore defined by sharp outer edges of the teeth.

In view of the brittle nature of the material of which the cap is moulded, these teeth are easily fracturable so that it is not possible, without breaking the teeth, for the cap to be gripped by a tool for unscrewing of the keg spear.

The free end part 25 of the skirt, projecting beyond the projections 14, has a chamfered end 26 to define a sharp, annular edge. In view of the briftleness of the material, this part 25 of the skirt will shatter if an attempt is made to grip the cap with a tool between the top 11 and the end 26 of the skirt for unscrewing the keg spear, on which the cap is mounted.

There is integrally moulded with the skirt 12, a radially, outwardly projecting tab 28 (Figures 1,3 and 4). This tab 28 is reinforced by a pair of gussets 29. Adjacent each gusset, the skirt has a line of weakness 30 extending from a corresponding slot 31 in the end part 25 of the skirt 12. Each slot 31 corresponds in position to a recess 19. The tab 28, therefore, can be grasped and pulled to tear the skirt 12 along the lines of weakness 30, so that the cap can be lifted off the keg spear.

The modified cap shown in Figures 5 to 7 is substantially of the same construction and the underneath plan view as shown in Figure 1, is identical for the modification. In this cap, the inclined peripheral position 13 of the top is omitted, the cap being shaped for a different keg spear, which has a wholly flat top. The top of this spear, is basically circular with three angularly spaced flats for gripping by a tool to unscrew the spear. In view of this change, it will be seen that the gussets 29 have a greater slope relative to the plane of the top and the teeth 20 are of greater height.

Claims

1, Atamperproof cap for a keg spear, the cap having a skirt provided with internal projection means for snap-engaging under a shoulder on the spear, the extreme outer periphery of the skirt being defined by a readilyfracturable edge, this edge being the only part of the skirt grippable by a tool to effect turning of the spear in use, the material of the cap being sufficiently resilient to permit said snap engagement, but sufficiently brittle for the cap to be damaged on removal and for said fracturable edge to be damaged when gripped by said tool for unscrewing the spear.

2. Atamperproof cap according to Claim 1, which is injection moulded and wherein the internal projection means comprises spaced projections around the inner periphery of the skirt and the top of the cap has mould-finger apertures aligned with the projections.

3. Atamperproof cap according to Claim 1 or 2, wherein the outer periphery of the skirt slopes to define a sharp edge.

4. Atamperproof cap according to Claim 1,2 or 3, wherein said edge is defined by a multiplicity of readily fracturable outwardly projecting teeth.

5. Atamperproof cap according to any preceding Claim, wherein the internal projection means has a bevelled underface angled with respect to the top face to serve as a lead-in to facilitate engagement over said shoulder.

6. A tamperproof cap according to any preceding Claim, wherein the skirt extends beyond the internal projection means in the direction away from the top of the cap, this extension portion of the skirt being readily fracturable.

7. Atamperproof cap according to Claim 6, wherein the extension portion of the skirt tapers to a sharp edge.

8. A tamperproof cap according to any preceding Claim, including a projecting tab provided on the skirt and one or more lines of weakness adjacent the tab to facilitate splitting of the skirt by pulling on the tab.

9. A tamperproof cap constructed substantially as herein described with reference to Figures 1 to 4 or Figures 5 to 7 of the accompanying drawings.

10. A keg fitted with a keg spear, and a cap according to any preceding claim mounted on the keg spear such that the keg spear cannot be unscrewed without damaging the fracturable edge and such that the cap cannot be forcibly removed from the keg spear without damage to the cap.