GB2383104A

GB2383104A - Nail with ribbed head

Info

Publication number: GB2383104A
Application number: GB0129619A
Authority: GB
Inventors: David Buckley
Original assignee: SEAC Ltd
Current assignee: SEAC Ltd
Priority date: 2001-12-11
Filing date: 2001-12-11
Publication date: 2003-06-18
Also published as: GB0129619D0

Abstract

A nail or pin 10 comprises a shank 12 with a tapered point 16 and a fibbed head 14. The ribs 22 extend along at least part of the length of the head 14 and may enable the nail to cut into a plastic substrate such as UPVC without it splitting. The head 14 is preferably made of a plastic such as polypropylene and may be integral with the shank 12. Alternatively, the shank 12 may be embedded in the head 14 and may be joined by an adhesive or by welding. The head 14 may take the shape of a plurality of frustra, of a cylinder connected to a prism, or of a truncated cone, typically with a base angle r of 45{ to 85{, preferably 80{. The head 14 may also comprise a rim 20 and may constitute 10% to 50%, preferably 20% to 33.3% of the nail's overall length. There are typically 4, 6 or 8 ribs 22, which are tapered so as to be thicker at the end furthest from the nail's point 16.

Description

PIN OR NAIL This invention relates to a pin or nail. Nails and pins have been used to fasten objects together for centuries.

In particular, plastics headed nails and pins are often used where fastening devices with a decorative head are required, e. g. for holding laminated boarding and extruded cladding such as uPVC extruded weather-boards. All plastics headed pins and nails have certain common features that are determined by their function, in particular pointed shanks and a laterally extending plastics head. The design of the plastics head of the pin or nail can vary depending on its intended function and aesthetic considerations.

Typical examples of such plastics headed pins or nails include those disclosed in UK Registered Design No. 1022136 (which has a head in the shape of a shallow hemispherical section with a flat top), UK Registered Design No. 1024441 (which has a head in the shape of a shallow frustoconical section with a flat top), UK Patent No. 702367 (which has a hemispherical head surrounding a shank), UK Patent No.

1004045 (which has a generally flat head having an annular projection so as to receive the end of a shank), and EP-A-187168 and EP-A- 189569 (which have a three-part head around a ringed shank).

There are several problems associated with known plastics headed pins and nails. Firstly, the design of the pins means that when they are driven into a plastic board, for example, the head is left proud of the surface. This often spoils the visual effect of the surface, the heads of the pins or nails being clearly visible, even at a distance. Secondly, a conventional nail or pin has a shank of rigid material, e. g. steel, which is driven through a plastics board, for example, such that the shank is perpendicular to the surface of the board, and into the body of the material to which it is to be affixed. The fixing action of this nail or pin is achieved by a"sandwiching"of the board between the head of the pin and the material into which the shank is driven. This fixing action produces a less than ideal grip.

The present applicant's GB-A-2268992 disdoses a plastics headed nail or pin comprising a shank of a rigid material with a point at the distal end of the shank and a plastics head at the proximal end, in which the plastics head is in the form of a frustoconical body coaxial with the shank, the shank being embedded in the plastics head such that the proximal end thereof is close to the wide end and such that the shank extends through the narrow end of the frustoconical body, the frustoconical body surrounding the shank and extending towards the distal end thereof to a substantial degree. Conveniently, the base angle of the frustoconical section between the base of the cone and the side may be from 650 to 850. The shape of the head of this nail results in a more discreet finish.

However, a problem exists with the nail described in the above document in that, when driven into a plastic substrate (in particular, a

uPVC board), the nail does not cut smoothly into the plastic substrate.

As a consequence, more force is required to drive the nail into the substrate. This leads to more plastic being displaced on insertion of the nail, which weakens the substrate and can lead to it splitting.

Therefore, it is an object of the present invention to provide a pin or nail, in particular a plastics headed pin or nail, capable of providing a satisfactory grip on a plastics substrate, while cutting more effectively into a plastics substrate on insertion, thereby ensuring that less plastic is displaced and minimising the risk of the substrate splitting.

According to the invention, there is provided a nail or pin comprising a shank of a rigid material with a point at the distal end of the shank and a head at the proximal end, the head bring coaxial with the shank and tapering towards the distal end of the shank, wherein the head is provided with ribs extending along at least part of the length thereof.

The shank of the nail or pin of the present invention is made of a rigid material, so that it can fasten a substrate firmly to the article to which fastening is desired. Examples of suitable materials include metals and alloys thereof such as iron, aluminium, zinc, tungsten, titanium, brass and steel, and composites such as carbon fibre. Typically the shank is made from steel.

The shank may take many different cross-sectional shapes depending on the intended use of the pin or nail and aesthetic considerations. For example, the shank may be circular or polygonal (eg triangular, square,

pentagonal, hexagonal etc. ) in cross-section. Preferably the shank is circular in cross-section.

There is no particular restriction on the nature of the material from which the head of the nail or pin of the invention can be made, provided that the material is strong enough so that the head will not shatter when the nail is driven into the substrate. Examples of possible materials include metals such as those described and exemplified above in relation to the shank, wood, carbon fibre, and plastics, (the term"plastics"includes any suitable thermoplastic or thermosetting polymer), e. g. polyethylene, polypropylene, uPVC, polyvinyl acetate, nylon, polyethylene terephtalate etc. It is preferred that the head is made from a plastics substance in order to provide a decorative finish as outlined above. The plastics may include a reinforcing material, for example metallic, glass or carbon fibres, to make it sufficiently shatter resistant.

The head may be provided on the shank of the nail or pin by any suitable means known in the art, for example, by welding or by means of an adhesive. The head may also be integrally formed with the shank.

However, it is preferred that the shank is embedded in the head, as this provides a stronger attachment between the head and the shank.

The head may extend towards the distal end of the shank to a substantial degree. In general, the ratio of the overall length of the pin or nail to the length of the head may be from 10: 1 to 2: 1, particularly from 5: 1 to 3: 1.

The head may be coloured or patterned for aesthetic purposes, for example so it matches the colour or pattern of the substrate.

The head of the nail or pin tapers towards the distal end of the shank (in other words, it is narrower nearer the distal end than the proximal end) so that the nail or pin may be driven in to the substrate while causing minimal lateral disturbance to its structure. A wide variety of possible shapes may be envisaged by the person skilled in the art. For example, the head may be generally circular or polygonal when viewed in crosssection. It is generally preferred, to ensure an optimum fit with the shank, that the head and shank have the same general cross-sectional shape. By "general cross-sectional shape" is meant the cross-sectional shape the head would exhibit in the absence of ribs.

It is preferred that at least a part of the head takes the general shape (ie its hypothetical shape in the absence of ribs) of a frustum (ie a truncated cone or pyramid) with the wider end thereof closer to the proximal end of the pin or nail. The head may, for example, take the general shape of a single frustum, a plurality of frusta fused together (the frusta decreasing in cross-sectional area towards the distal end), or a frustum fused at its wider end to a cylinder or prism, ie to a body of the same general crosssectional shape but of constant width. It is especially preferred that the head takes the general shape of a truncated cone.

In a preferred embodiment of the invention, the head is provided with a thin, laterally extending annular rim at the proximal end of the nail.

When the head (or part thereof) takes the general shape of a frustum, the base angle of the frustum (ie that between the cone or pyramid base and the side) may vary depending on the substrate for which the pin or nail is intended. When the head takes the general shape of a plurality of fused frusta, the base angle is widest for the largest frustum and shallowest for the smallest. The base angle may be between 50 and 850. However, it is preferred that the base angle is from 45 to 85 , as it is believed that a frustal or part-frustal head with this angle concentrates splitting of the substrate closer to the hole made by the nail in use. In a particularly preferred embodiment, the base angle is about 80 .

The head of the nail or pin of the present invention is provided with ribs.

The provision of ribs on the head of the nail or pin of the present invention achieves the objectives outlined hereinabove in that, in use, the nail or pin is capable of cutting more smoothly into a plastic substrate than those of the prior art. Less plastic is therefore displaced when the nail is inserted into the substrate, and less damage done to its structure, thereby preventing the substrate from splitting.

The number, nature and layout of the ribs may be varied by the skilled person depending on the general shape of the shank and head and the type of substrate requiring fixing. The ribs extend along at least part of the length of the head such that they are parallel with the axis of the shank. To facilitate even cutting into the substrate, it is preferred that the ribs are spaced evenly around the head.

For a nail or pin which is polygonal in cross-section, the number of ribs may advantageously match the number of sides of the polygon. For

nails or pins generally circular in cross-section, an even number of ribs is preferred, and 4,6 or 8 ribs more preferred.

The ribs may preferably extend substantially all the way along the length of the tapered head (ie up to but not including the rim if present) so that the pin or nail may cut effectively into a plastic substrate right to its end.

The thickness of the ribs (by which is meant the distance of the location on the ribs radially furthest from the axis of the pin or nail to the point the ribs adjoin the head) may vary along their length so that the nail or pin may cut more effectively into a plastics substrate. Typically, the ribs decrease in thickness towards the distal end of the head.

In a particularly preferred embodiment, the ribs may be of intermediate thickness at the proximal end of the head, reach their thickest point at an intermediate point along the head, and then decrease in thickness again along the length of the head. Where the head takes the shape of a plurality of fused frusta or of a frustum fused to a cylinder or prism, the thickest point of the ribs may advantageously be near the point where the smaller frustum meets the cylinder, prism or larger frustum.

In use, the pin or nail of the invention is driven though the substrate, e. g. a uPVC board, and into the body to which it is being fixed, e. g. a wooden beam. When the visible shank has been driven into the body to be fixed, the tapered head of the pin or nail is further driven into the substrate until the top surface of the wide end of the tapered head is essentially flush with the substrate.

When the head takes the shape of a frustum fused to a cylinder or prism of the same general cross-sectional shape (or to a larger frustum of wider base angle), the smaller frustum portion cuts into the substrate.

Once the smaller frustum portion is fully inserted in the substrate, the cylindrical, prismatic or larger frustum portion fits into the hole left by the smaller frustum portion. This shape of head therefore provides an additional advantage in that the size of the smaller frustum portion of the head (which provides a cutting part but can also cause splitting) is reduced to the minimum necessary to carry out cutting, thereby further reducing splitting of the substrate.

In pins and nails of the invention having a rim at the proximal end, the rim may be tapered towards its edge so as to give a particularly flush finish. This consequently gives a considerably more discreet finish than is obtained using the plastics headed pins and nails of the prior art whose heads are inevitably left proud of the surface.

In a preferred embodiment of the invention, the shank of the pin or nail is ringed in order to provide further improved grip.

The invention may be further understood by consideration of specific embodiments of the invention, with reference to the accompanying drawings, in which: Figure 1 shows a nail according to the invention; Figure 2 is a section along the line B-B of the nail of Fig. 1; and

Figure 3 shows a nail according to an alternative embodiment of the invention.

In Figure 1 there is shown a nail 10 according to the present invention comprising a shank 12 formed from a rigid material such as steel, the shank 12 being ringed in order to give good grip. The shank has a sharp point 16 at the distal end of the pin, and a head 14 at the proximal end of the pin formed from a resilient plastics material such as polypropylene.

The head 14 takes the shape of a frusto-cone 18. At the proximal end of the head 14 there is a thin, laterally extending annular rim 20. The head extends along the shank towards the distal end of the pin. As can be seen from Figure 2, the shank 12 is embedded in the plastics head 14.

T he base angle 8 between Ole cone and the Se A-A is lvpicapi about 800.

The head is provided with ribs 22. The ribs vary in thickness along the length of the head, being of intermediate thickness at the proximal end of the nail where the head meets the rim 20 then broadening out to reach maximum thickness at the line A-A. The ribs then decrease in thickness towards the distal end of the head.

Figure 3 illustrates a nail 10'according to an alternative embodiment of the invention, in which the shank 12'and head 14'are square in crosssection. The head 14'takes the shape of a smaller truncated square pyramid 24 fused at the line C-C to a larger truncated square pyramid 26. The head 14'is provided with ribs 22'along each of its edges. The ribs are of intermediate thickness at the proximal end of the nail where

the head 14'meets the rim 20'. The ribs then increase in thickness along the length of the head, reaching maximum thickness at the line DD. The ribs then decrease in thickness towards the distal end of the head 14', merging into the head 14'where it meets the shank 12'.

Claims

CLAIMS 1. A nail or pin comprising a shank of a rigid material with a point at the distal end of the shank and a head at the proximal end, the head bring coaxial with the shank and tapering towards the distal end of the shank, wherein the head is provided with ribs extending along at least part of the length thereof.
2. A nail or pin according to Claim 1, wherein the head is made from a plastics material.
3. A nail or pin according to Claim 1 or Claim 2, wherein at least a part of the head takes the general shape of a frustum, the wider end of the frustum being closer to the proximal end of the nail or pin.
4. A nail or pin according to Claim 3, wherein the head takes the general shape of a single frustum.
5. A nail or pin according to Claim 4, wherein the head takes the general shape of a truncated cone.
6. A nail or pin according to Claim 3, wherein the head takes the general shape of a plurality of fused frusta, the frusta decreasing in cross-sectional area towards the distal end of the nail or pin.
7. A nail or pin according to Claim 3, wherein the head takes the shape of a frustum fused to a cylinder or prism.

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8. A nail or pin according to any one of Claims 1 to 7, wherein the head has at the proximal end thereof a thin, laterally extending annular rim.
9. A nail or pin according to any one of Claims 1 to 8, wherein the ratio of the overall length of the pin or nail to the length of the head is from 10: 1 to 2: 1.
10. A nail or pin according to Claim 9, in which the ratio of the overall length of the pin or nail to the length of the head is from 5: 1 to 3: 1.
11. A nail or pin according to any one of Claims 1 to 10, wherein the shank is embedded in the head.
12. A nail or pin according to any one of Claims 1 to 11, provided with 4,6 or 8 ribs.
13. A nail or pin according to any one of Claims 1 to 12, wherein the ribs decrease in thickness towards the distal end of the nail or pin.
14. A nail or pin according to Claim 13, wherein the ribs are of intermediate thickness at the proximal end of the head, of maximum thickness at an intermediate point along the head, and decrease in thickness towards the distal end of the nail or pin.
15. A nail or pin substantially as described herein with reference to the accompanying drawings.