GB2267144A - Vacuum flask - Google Patents

Abstract

A container assembly in the form of a vacuum flask has a glass filler 1 housed within a body 2 formed by plastics moulded housing and base parts 3 and 10. The pans 3 and 10 engage through screw threads 11 and 12 for the base part 10 to maintain the filler 1 within the body 2 and bias the rim 6 of the filler against an annular seal 14. An annular flange 15 moulded integral with the base part 10 extends between the base part and an opposing surface 3A of the housing part 3 to form an annular seal between those parts on the side of the thread on the base part axially remote from the end of that thread which leads during engagement of the base part in the housing part. The annular seal formed by the flange 15 alleviates leakage by way of the co-operating screw threads in the event that the filler is broken. <IMAGE>

Description

TITLE "A container assembly" TECHNICAL FIELD & BACKGROUND ART The present invention relates to a container assembly of the kind in which a container part of the assembly is housed within a hollow body so that contents of the container part may be poured through a closable open top of the hollow body. An example of such a container assembly is where the container part provides thermal insulation to the contents and may be in the form of a double walled vacuum insulated filler as is well known in the structure of vacuum flasks.

With container assemblies of the kind referred to it is known, for convenience of assembly, for the hollow body to be formed of a plastics moulded housing part (within which the major portion of the container part is usually received) and a base part which screw threadedly engages with the housing part to retain and secure the container part within the body. Usually the housing and base parts are moulded in plastics material, particularly for vacuum flasks in the nature of leisure ware, and the open top of the hollow body through which the container contents may be poured is closable by a stopper or bung which normally screw threadedly engages with the housing part.

Container assemblies of the kind discussed are frequently used for the storage and carriage of hot liquid and in the event that the container part breaks or dislodges from a seal which its mouth normally forms with the housing part, it is possible that the hot liquid can leak into the chamber of the hollow body and seep through the engaging screw threads between the housing and base parts, possibly scalding persons handling the container assembly. Also any leakage of liquid generally as aforementioned through the co-operating screw threads can provide unacceptable contamination or staining. This possible leakage from the container assembly is particularly undesirable with vacuum insulated flasks where the container part is a glass filler which may be susceptible to breakage if the assembly is dropped.It is an object of the present invention to provide a container assembly of the kind discussed by which leakage from the hollow body by way of co-operating screw threads between component parts of that body is alleviated in a relatively simple and economical manner.

STATEMENT OF INVENTION & ADVANTAGES According to the present invention there is provided a container assembly having a container part within which contents are to be contained for pouring through a closable open top of a hollow body within which the container part is housed, the hollow body comprising two plastics moulded body parts which are axially engaged one within the other by a male screw thread integral with one of the body parts co-operating with a complementary female screw thread integral with the other of the body parts, and wherein one of said body parts has an integral radially extending flexible annular flange which during engagement of the male and female screw threads resiliently abuts the other of the body parts to provide an annular seal between those parts.

The present invention was primarily developed for insulated container assemblies in which the container part is a double walled glass vacuum insulated filler. Such vacuum insulated flasks are well known where one of the body parts is in the form of a housing part within which at least a major portion of the filler is housed and the other body part is in the form of a base part which screw threadedly engages with the housing part to secure and retain the filler in the hollow body and so that a mouth of the filler which opens to the container cavity has its rim urged into sealed engagement with the body for the mouth to communicate with the open top of the body.When the open top 6f the body is closed and sealed by a removable bung or stopper it will be appreciated that the container part or filler is housed within a closed chamber so in the event that the filler breaks (or otherwise discharges fluid into the closed chamber of the body) such liquid is restrained from leaking to the exterior of the body by way of the cooperating screw threads by the integral annular flange which extends radially from one body part to abut and form a seal with the other body part. The annular flange may be relatively thin walled in comparison with the wall of the body part from which it extends to be relatively flexible and resilient and form a tight and continuous circumferential seal with the body part which it abuts.

Preferably the annular seal is on the body part having the male thread and is located on the side of the screw thread of that body part which is axially remote from the end of that screw thread which leads in effecting the screw threaded engagement between the two body parts. With such an arrangement it will be appreciated that there is no necessity for the annular flange to slide axially over the female screw threads of the body part against which it abuts (thereby alleviating unnecessary wear and damage to the annular flange).

Desirably the annular flange is curved in radial section to present a convex face which leads to form the seal and a concave face which trails in effecting the screw engagement between the two body parts. In a preferred structure the annular flange is of part annular shape in radial section and extends substantially tangentially from the body part with which it is integrally formed.

The annular flange will usually extend radially from a substantially cylindrical surface of the body part with which it is integral to form a seal against an opposing substantially cylindrical surface of the other body part.

The two cylindrical surfaces will usually be substantially co-axial and have a relatively small radial clearance between them to accommodate for the co-operating male and female screw threads.

In a preferred construction in which the hollow body comprises the previously mentioned housing and base parts, the base part has the male thread integral therewith to be received within the housing part having the female thread and the annular flange is integral with the base part; it is possible however to have a reverse structure in which the housing part has the male thread integral therewith which is received within the base part having the female thread and the annular flange is integral with the housing part.

DRAWINGS One embodiment of a container assembly in the form of a vacuum flask will now be described, by way of example only, with reference to the accompanying illustrative drawings, in which: Figure 1 is an axial section through the flask; Figure 2 shows an axial section through a base of the flask shown in Figure 1, and Figure 3 shows a detailed enlargement in axial section of a male screw thread and annular flange provided on the base shown in Figure 2.

DETAILED DESCRIPTION OF DRAWINGS The flask assembly shown in Figure 1 may, for a major part of its construction and for convenience of discussion, be regarded as conventional comprising a glass double walled vacuum insulated bottle or filler 1 housed within a generally cylindrical hollow body 2. The major part of the bottle 1 is accommodated within a cylindrical housing part 3 of the body 2 which tapers through a shoulder 4 to provide a top opening 5 to the body. The top opening 5 communicates with a mouth 6 of the filler 1 through which contents of the filler may be poured. The opening 5 can be closed and sealed by a removable stopper 7 which screw threadedly engages with a tubular collar 9 extending from the shoulder 4.

The body 2 includes a generally cylindrical cup shaped base part 10 which is axially received partly within the end of the housing part 3 remote from its top opening.

The base part 10 has an external (male) thread 11 which screw threadedly engages with an internal (female) thread 12 in the housing part 3 to retain the parts 3 and 10 together axially. As the base part 10 is screwed into engagement with the housing part 3 it abuts the filler 1 (as indicated at 13) to bias the filler axially in the housing part 3 for the rim 6A of its mouth 6 to move into sealing abutment with an annular seal 14 carried by the shoulder 4.

The housing and base parts 3 and 10 are formed as plastics mouldings, conveniently in polypropylene, with integral threads. Integrally moulded with the base part 10 is a radially outwardly extending annular flange 15.

The flange 15 is spaced axially from the male screw thread 11 but adjacent to the end of that screw thread remote from its end which leads during screw threaded engagement with the female thread 12 of the housing part 3. As will be best seen from Figure 3, the annular flange 15 is of generally part annular shape in radial section to extend substantially tangentially from a cylindrical surface l0A of the base part 10 and so that it presents a convex surface 15A in the axial direction in which the base part leads during its screw threaded engagement with the housing part 3 and an axially opposing concave surface 15B which trails during said engagement.During engagement between the base and housing parts and as the base part is screwed into the housing part, the annular flange 15 abuts and slides along an opposing cylindrical surface 3A (Figure 1) of the housing part 3. The surfaces 3A and l0A are coaxial. In its unstressed condition the flange 15 has a maximum diameter slightly greater than the internal diameter of the surface 3A and the wall thickness of the flange 15 is relatively small in comparison with the general wall thickness of the base part 10 so that the resilience of the plastics material permits the flange to flex and move into firm sealing abutment with the surface 3A when the threads 11 and 12 are engaged to provide the required securement for the bottle 1.

From Figure 1 it will be seen that the filler 1 is retained within the chamber of a body that is closed by the stopper 7 (which will be sealed with respect to the collar 9 of the housing part 3). In the event that the bottle 1 is broken, liquid which enters the chamber of the body 2 and may seep between the co-operating screw threads 11 and 12 is restrained against escaping from the body by the sealing effect provided by the annular flange 15.

It is appreciated that the provision of the annular flange 15 on the base part 10 is a relatively simple modification to what may be regarded as a conventional form of base part but nevertheless tests have indicated that the flange 15 is extremely effective in alleviating leakage from the body part bearing in mind the clearances which are normally provided between co-operating plastics moulded screw threads. The formation of the flange 15 as shown in Figure 2 can be achieved by use of a relatively simple moulding tool structure for defining the exterior of the base part 10 below its open top. For example a single moulding tool part may be used to define the profile of the base part as shown in Figure 2 which extends from and below the concave underside annular surface of the flange 15 and radially separable split moulding tool parts may be used to define the external surface of the base part extending upwardly in Figure 2 from and including the convex surface 15A of the flange 15 and also including the external threads 11.

In Figure 1 there is shown an inverted drinking cup 20 which screw threadedly engages at 21 with the shoulder 4.

Although it will be appreciated that the cup has no relevance to the present invention, it is shown as typically being provided on a vacuum flask for leisure ware of the kind exemplified.

Claims (9)

1. A container assembly having a container part within which contents are to be contained for pouring through a closable open top of a hollow body within which the container part is housed, the hollow body comprising two plastics moulded body parts which are axially engaged one within the other by a male screw thread integral with one of the body parts co-operating with a complementary female screw thread integral with the other of the body parts, and wherein one of said body parts has an integral radially extending flexible annular flange which during engagement of the male and female screw threads resiliently abuts the other of the body parts to provide an annular seal between those parts.

2. An assembly as claimed in claim 1 in which one body part comprises a housing part in which at least a major portion of the container part is housed and the other body part is a base part by which the container part is secured and retained in the housing part.

3. An assembly as claimed in either claim 1 or claim 2 in which the annular flange is on the body part having the male screw thread and is located on the axial side of the screw thread on that body part remote from the end of that screw thread which leads in effecting the screw threaded engagement between the two body parts.

4. An assembly as claimed in any one of the preceding claims in which the annular flange is curved in radial section to present a convex face which leads to form the seal and an axially opposing concave face which trails in effecting the screw threaded engagement between the two body parts.

5. An assembly as claimed in claim 4 in which the annular flange is of generally part annular shape in radial section and extends substantially tangentially from the body part with which it is integral.

6. An assembly as claimed in any one of the preceding claims in which the annular flange extends radially from a substantially cylindrical surface of the body part with which it is integral and forms a seal against an opposing and co-axial substantially cylindrical surface of the other body part.

7. An assembly as claimed in claim 2 or in any one of claims 3 to 6 when appendant to claim 2 in which the base part has the male thread integral therewith to be received within the housing part having the female thread and said annular flange is integral with the base part.

8. An assembly as claimed in any one of the preceding claims in which the container part is a glass double walled vacuum insulated glass having a mouth which is biased into and maintained in sealed engagement with the body by screw threaded engagement between the two body parts.

9. A container assembly substantially as herein described with reference to the accompanying illustrative drawings.