WO1998047784A1

WO1998047784A1 - Container having a self-cleaning closure

Info

Publication number: WO1998047784A1
Application number: PCT/GB1997/001072
Authority: WO
Inventors: Robert Malcolm Olliffe
Original assignee: Robert Malcolm Olliffe
Priority date: 1997-04-17
Filing date: 1997-04-17
Publication date: 1998-10-29
Also published as: AU2572897A

Abstract

A container is described which has a threaded neck (2) and cap (1) and is of the kind intended for packaging paint, varnish or mastic materials which solidify on exposure to air. The cap (1) includes a tooth portion (13) which is disposed to clear material trapped between the threads as the cap is screwed on or off the neck.

Description

CONTAINER HAVING A SELF-CLEANING CLOSURE

This invention relates to containers and particularly containers having a closure comprising a threaded neck and cap.

It is a well known experience that containers of this kind which are used to hold materials which solidify when exposed to air become encrusted with solidified materials around the threads, and this makes it very difficult to re-close the cap

One example of products for which this is a particular problem are artist's oil paint, cements and mastic materials which are commonly packed in collapsible tubes having a threaded closure. Often, the threads are clogged to the point where it is impossible to re-close the container effectively and, as a result, a half-used container of expensive material is often discarded.

It is an object of the present invention to provide a container having a self-cleaning closure.

According to one aspect of the invention there is provided a container having a closure which comprises a threaded neck and cap wherein the thread on the neck or cap is formed with a tooth portion disposed to clear material between the threads as the cap is screwed on or off the neck.

According to a further form of the present invention, there is a provided a container having a closure comprising a threaded neck and cap wherein the thread on the cap or neck has a interrupted portion which provides a face extending transversely of the thread for cleaning the thread.

Thus, in accordance with the invention the self-cleaning device incorporated in the thread may comprise a tooth portion which is formed as part of the lead screw portion of the thread or is formed at some point along the thread as an interrupted portion thereof. There may be advantages in providing that the tooth portion is formed as an interrupted part of the thread inasmuch as this arrangement does not interfere with the formation of the lead part of the screw. Alternatively, the tooth portion may be formed in such a way as to provide the neck or the cap with a multi-start screw thread.

In general, it is more convenient to provide for the tooth ponion on the cap rather than on the threaded neck but, in theory, the tooth portion can be on either.

Where the cap is formed as a conventional threaded cap, it may be modified in accordance with the invention by being slotted to provide for the tooth portion. However, in practice, it would normally be convenient to form the tooth portion on the cap during the manufacture of the cap, e.g. by moulding from a plastics material.

The present invention will be illustrated by the accompanying drawings, in which: -

Figure 1 is a side elevation of a cap and part of a threaded neck of a container, the container not being shown;

Figure 2 is a perspective view of a cap;

Figure 2A is an elevation showing the manner in which the threads of the cap mate with the threads of a corresponding threaded neck;

Figure 3 A is a side elevation of a cap similar to that shown in Figure i;

Figure 3B is a perspective view of the cap shown in Figure 3 A but without showing the flange on the top of the cap; Figure 3C is a plan view of the cap shown in Figure 3B; and

Figures 3D, 3E and 3F show various modifications of the tooth portion of the thread.

Referring to the drawings, Figure 1 shows a cap (1) about to be screwed onto the threaded neck (2) of a container (not shown). Cap (1) includes a flange portion (3) to facilitate the securing of the cap to the container and its removal, and this is generally moulded integrally with the body portion (4). The body portion (4) has an internal thread designed to mate with a thread (5) on the neck portion (2). The thread on the neck portion (2) has a conventional start (6) tapering away to the body of the neck.

In contrast, the upper part of the body (4) is cut away at (8) to provide a face (7) extending substantially transversely to the threads (5). As a consequence, when cap (1) is placed on the end of threaded neck (2), the inclined face (7) clears out any solidified material which has become embedded in the threads (5). To facilitate screwing of the cap onto the neck, the body portion (4) of the cap is lengthened so as to provide an extended guide portion. This is shown more clearly in Figure 2, wherein the same reference numerals are used for equivalent features. In the case of the embodiment shown in Figure 2, a face (7) to the thread (10) is formed by slotting the cap (1) at (11) thus providing an extended guide portion (12) on the cap. The face (7) works in the same way as described in connection with Figure 1, providing a face (7) having a pointed tooth portion (13) which effectively clears out material embedded in threads on the cap. Referring to Figures 3 A to 3C, these show an arrangement very similar to that shown in Figure 1 and similar reference numerals are applied to corresponding portions.

Figures 3D to 3F illustrate modifications of the tooth portion (7) and (13). These show that the tooth portion can be extended radially so as to provide a pointed tooth portion (13) which digs in more effectively into hardened portions of material in the threaded closure.

It will be appreciated that the vertical and longitudinal angles of the surfaces of the tooth portion can be varied to suit different materials.

A feature of the thread design of the present invention is that in contrast with a conventional thread, the internal diameter of the thread is generally of constant diameter whereas in a conventional thread, the internal diameter is increased at the point where the thread leads in. This leads to the advantage that there is less likelihood of the threads of the cap and neck becoming crossed.

Claims

CLAIMS: -

1. A container having a closure which comprises a threaded neck and cap wherein the thread on the neck or cap is formed with a tooth portion which is disposed to clear material trapped between the threads as the cap is screwed on or off the neck.

2. A container having a closure comprising a threaded neck and cap wherein the thread on the cap or neck has an interrupted portion which provides a face extending transversely of the thread.