GB2273325A

GB2273325A - Improved screw with depth setting flange

Info

Publication number: GB2273325A
Application number: GB9225889A
Authority: GB
Inventors: John Conroy
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-12-11
Filing date: 1992-12-11
Publication date: 1994-06-15
Anticipated expiration: 2012-12-11
Also published as: GB2273325B; GB9225889D0

Abstract

In order to overcome the problem of sag which can occur where a screw enters a wall plug, resulting in a breakdown of the surrounding wall surface, a depth setting disc (16) is provided on the shank portion (12) of the screw, the disc being larger in diameter than the screw head (14). The disc (16) is preferably an integral part of the screw. The disc diameter is preferably about 8 mm greater than the diameter of the screw head. <IMAGE>

Description

IMPROVED SCREW This invention relates to screws.

Conventionally, screws comprise a threaded portion for entry into a receiving surface, a shank which normally has a smooth external surface and a head portion which is designed to receive a screwdriver or other tool which is used to turn the screw.

For the hanging of mirrors or display cabinets on walls or for the suspension of items which use hanging brackets, there is the problem that sag can occur at the face of the fixing where the screw enters the wall plug. The surface of the wall or other receiving body can break down under the load, particularly if the screw is to be inserted into plasterboard or hardboard.

It is an object of the present invention to provide an improved screw which is designed to give extra strength to wall fixings by preventing the occurrence of sag.

Broadly in accordance with the invention there is provided a screw which is provided with a setting disc on the shank portion of the screw which is larger in diameter than the screw head.

The setting disc is preferably integral with the screw for strength and security.

Preferably, the diameter of the setting disc is of the order of 8 mm larger than the diameter of the screw head.

The disc is preferably positioned at a distance of the order of 2 mm from the longitudinally inward end of the head portion of the screw, in order to have a sufficient length of screw protruding for suspension purposes. However, other distances could alternatively be used, depending upon the particular use to which the screw is to be put.

In order that the invention may be more fully understood, one presently preferred embodiment of screw in accordance with the invention will now be described briefly by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a side view of the screw; Fig. 2 is an end view of the screw; and, Fig. 3 shows the screw fitted into a wall or other receiving surface.

As shown in the drawings the screw comprises a threaded portion 10, a smooth-surfaced shank portion 12 and a head portion 14 which is slotted. The illustrated screw is a countersunk screw, but it is to be understood that the invention is applicable to any type of screw. Integral with the shank portion 12 of the screw is a cylindrical disc 16 which constitutes the depth setting disc. This disc extends radially and preferably has a thickness of the order of 2 mm. It is made from the same material as the screw.

The diameter of the disc 16 is greater than that of the screw head 14. Preferably, the diameter of the disc 16 is approximately 8 mm larger than the diameter of the screw head 14. In the illustrated embodiment the diameter of the screw head 14 is 8 mm and the diameter of the disc 16 is 16 mm. With larger screws having larger diameter screw heads the diameter of the disc 16 must be increased so that the 8 mm differential is maintained. The differential figure of 8 mm is not absolute but it has been found that this is the preferred order of magnitude for this dimension.

The particular reason for the enlarged diameter of the disc 16 is so that it will reliably cover the underlying screw-fixing plug which is shown at 18 in Fig. 3. The disc 16 is of sufficiently large diameter not only to encompass the end of the wall plug 18 but also to overlie the adjacent surrounding wall surface in order to prevent this being worn away or compressed, causing sag, when a fitting is suspended from the screw.

In the illustrated embodiment the setting disc 16 is positioned at a distance of approximately 2 mm from the longitudinally inward end of the screw head 14. This distance, although preferred, is not essential, and other spacings could alternatively be used, depending upon how far one wishes the screw head to project from the receiving surface in use.

Screws made in accordance with the invention will always be fitted at the right depth, because of the contact of the depth setting disc 16 with the receiving surface, and the construction also facilitates the removal of items, for example to facilitate redecoration.

As mentioned above, the present invention is applicable to all types and sizes of screw.

Claims

CLAIMS:

1. A screw having a head, a shank portion and a threaded portion, wherein a setting disc is provided on the shank portion which is larger in diameter than the screw head.

2. A screw according to claim 1, in which the setting disc is an integral part of the screw.

3. A screw according to claim 1 or 2, in which the diameter of the setting disc is of the order of 8 mm greater than the diameter of the screw head.

4. A screw according to any preceding claim, in which the setting disc is positioned at a distance of the order of 2 mm from the longitudinally inward end of the screw head.

5. A screw according to any preceding claim, in which the setting disc has a thickness of the order of 2 mm.

6. A screw substantially as hereinbefore described with reference to the accompanying drawings.