GB2027834A - Fasteners - Google Patents

Abstract

A fastener for engagement in a masonry structure comprises a tubular component (12) formed by bending a length of C-section material in its middle to form a closed end in which is formed an opening (17), to receive a plain fastener (13), the cross-sectional shape of the first portion of the tubular component (12), near said closed end, being circular and the cross-sectional shape of the remainder being flattened so as to have a dimension perpendicular to the plane of the abutting edges of the two C-shaped portions of the component, which is larger than the dimension in said plane, the plain fastener (13) being arranged to pass through said opening (17) and through both portions of the component, the plain fastener (13) having a diameter larger than the interior of the said first portion and even larger than the narrower internal dimension of the said remainder, whereby greater expansion of the component occurs over said remainder than in said first portion. <IMAGE>

Description

SPECIFICATION Fasteners This invention relates to fasteners for use in fixing into relatively hard materials such as brick, concrete or other composite building material blocks.

In our Patent Application No. 14231/76 there is described and claimed a fastener for such a purpose. This has a tubular comonent formed from C-shaped material and having one closed end, the material being bent over at the closed end to form a circular section, with two opposite longitudinal slits, the closed end having an opening to receive a plain fastener component engageable within the tubular component. With this fastener the plain fastener component is driven into the tubular component from the closed end and since it is of larger cross-section than the interior of the tubular component, it expands the latter to grip within a hole in a building block.

These fasteners are sometimes to be used in blocks which have internal cavities, usually for lightening. If a hole to receive a fastener is drilled right into one of these cavities, this sometimes results in some of the material surrounding the hole, within the cavity end, breaking away. When the fastener is expanded, in such a case, the grip is only over a short distance, so that the pulling out strength or resistance of the fastener may be impaired.

Similarly the naterial of the block may be crushable to some extent, which also results in a fastening with less strength than may be desirable.

It is the object of this invention to provide a fastener for use in relatively hard materials which has adequate provision for expansion to allow a secure fastening to be made, even if some of the material of the block becomes crushed or broken.

In accordance with the present invention a fastener comprises a tubular component formed from generally C-shaped material, one end being closed, the material being bent over at the closed end to define two opposite longitudinal generally co-planar slits extending to the closed end, the cross-sectional shape of a first portion of the tubular component, nearer to the closed end, being circular and the cross-sectional shape of a further portion extending to the other end, having a dimension transverse to the common plane of the slits longer than its dimension along said plane, the closed end of the tubular component having an opening to receive a plain fastener component engageable within the tubular component and of a length to occupy substantially the whole length of the interior of the tubular component, the cross-section of the plain fastener component being larger than the interior of the first portion of the tubular component and also larger at least than the narrower internal dimension of the further portion, the arrangement being such that, upon insertion of the plain fastener component, expansion of the tubular component will occur, such expansion being of greater extent over said further portion in the direction transverse to said plane of the slits, than over said first portion.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figures 1A., 1B., and lCshow a fastener constructed in accordance with the invention showing three stages of fixing; Figure 2 is a perspective view of the tubular component of the fastener; Figure 3 is a cross-section on the line 3-3 in Fig. 2, but including also the plain fastener component; and Figure 4 is a similar cross-section on the line 4-4 in Fig. 2.

Figs. 1A, 1B, and 1C show a building block 10 and a wooden batten 11 or other structure to be attached to the block 1 0. The block may be brick, concrete or other building material and is shown having a finite depth less than the length of the fastener. In one example, the block may be provided with an internal cavity which is therefore inaccessible from the side to which the batten 11 is attached.

The wooden batten 11 shown is merely an example of a structure which may be attached by means of the fastener which may be used for securement of any structure of wood or metal to a building block.

The fastener is, however, designed to provide secure fixing within a building block whether or not the end of the fastener enters a cavity and whether or not the fastener therefore passes right through the block.

Fig. 1A shows the two components of the fastener. There is a tubular component 1 2 and a plain fastener component 1 3. Fig. 2 also shows the tubular component on an enlarged scale. This is formed initially from material which is C shaped in cross section.

This section is seen in Fig. 3. This tubular component is formed from a straight length of such material being bent in the middle to form two equal length limbs 14, 1 5. At the junction of these two limbs there is formed an integral head 1 6 which is flattened on its outward face. This flattened end has a central opening 1 7 which lies on the central axis of tubular component and is therefore concentric with the interior of this component.

Fig. 3 shows the cross section of the tubular component over a first portion extending from the head 1 6 to a position approximating to 1/3rd of the length of the tubular component from the end remote from the head. Over this first portion the C-shaped material is unmodified in section and thus provides two semi-circular portions divided by co-planar slits 18, 19.

A further portion of the tubular component occupying the remaining Y3rd of the length thereof has a different cross-section as shown ifl Fig. 4. The C shaped material is modified by flattening in a direction transverse to the plain of the slits 18, 19, which also extend through this portion. This flattening produces fhe U shaped section shown in Fig. 4 wherein the dimension transverse to the plane of the slits 18, 19 is substantially greater than the dimension in said ptain.

As shown in Figs. 1 A and 2, the tubular component is constructed with the edges of the two limbs 14, 15 5 in contact or very closely spaced throughout the whole of their length.

The plain fastener component 13 is in the form of an elongated cylindrical pin with a head 20 at one end. The cylindrical portion has an external diameter of a size equal to or slightly smaller than the opening 1 7 in the head 16 of the tubular component. The diameter of the cylindrical portion of the plain fastener component 1 3 is, moreover, slightly larger than the combined circular internal diameter of the two limbs 14, 15 over the first portion of the tubular component as shown in Fig. 3.

Furthermore, the diameter of this cylindrical portion of the plain fastener component 1 3 is larger than the internal width of the U section of the limbs 14, 15 over said further portion.

As shown in Fig. 4, such diameter approximates to the external width of the U section of these limbs 14, 15 so that the internal width is substantially less than this diameter.

Fig. 4 shows the plain fastener component 13 occupying a position between these limbs 14, 15 and shows that the internal edges of the U shaped section engage on the exterior of the plain fastener portion with substantial separation of the limbs 14, 15.

Referring to Figs. 1 A, 1 B and 1C, these show three stages in the fixing of a fastener into the building block 10.

The first stage is to drill a hole 21 in the building block 10 as well as in the wooden batten 11. The tubular component 12 is now driven into this hole so that its head 1 6 lies against the face of the wooden batten or is embedded therein as shown in Fig. 1 B. In this condition, the tubular component has its two limbs 14, 15 lying close together and at- though the width over said further portion is greater in one dimension than the external diameter of said first portion, this does not exceed the width of the head 16.

Fig. 1 B shows the introduction of the plain fastener component 1 3. This is driven in by hammer blows and in the conditition shown in Fig. 1 E initial expansion of the first portion of the tubular component is taking place. This condition is shown in Fig. 3 and is usually sufficient to form a tight grip in the hole 21.

Fig. 1 C shows the plain fastener component 1 3 driven fully into the tubular component.

As drawn, the further portion of the tubular component which allows a greater extent of expansion than that produced by a passage of the plain fastener component through the said first portion extends beyond the rear face or into the cavity within the building block 10.

Passage of the plain fastener component into this portion provides the expansion conditions illustrated in Fig. 4, but since the limbs of the tubular component are substantially straight. the tapered effect illustrated in Fig.

1C is produced. Most of the expansion therefore takes place at the zone of transition between the first and further portions of the tubular component.

The flared configuration illustrated in Fig.

1C ensures that a secure fastening in a building block even if part of the block has been crushed or broken away particularly in the region of the rear face or interior of the cavity of the building block.

The fastener shown is not removable once it has been fixed.

However, in an alternative construction it is possible to remove the fastener if required. In such an arrangement the plain fastener component has no head. When removal is required, a pin or other elongated element is used to drive the plain fastener right through.

The diameter of such pin or element is such as to allow it to be withdrawn again after the plain fastener has left the end of the tubular component.

The tubular component itself can now be withdrawn with the aid of a claw hammer or the like. In the case of a cavity wall the plain fastener would simply fall into the cavity.

Where the fastener is fitted into a blind hole in a block, the hole must be long enough to accommodate the plain fastener beyond the end of the tubular component.

Other cross-sectional shapes of the further portion of the tubular component can be used but the U shaped section illustrated in Fig. 4 can be conveniently produced by flattening the C section shown in Fig 3. Other oval eliptical or oblong shapes can however be adopted.

The lengths of the respective portions of the tubular component may be varied in accordance with requirements. Furthermore, although the plain fastener component is preferably of a length equal to that of the tubular component it may be shorter though it must extend substantially into the said further portion to provide the greater expansion thereof referred to.

Different head formations may be used both on the tubular component and on the plain fastener component.

Claims (3)

1. A fastener comprising a tubular component formed from generally C-shaped material, one end being closed, the material being bent over at the closed end to define two opposite longitudinal generally co-planar slits extending to the closed end, the cross-sectional shape of a first portion of the tubular component, nearer to the closed end, being circular and the cross-sectional shape of a further portion extending to the other end, having a dimension transverse to the common plane of the slits longer than its dimension along said plane, the closed end of the tubular component having an opening to receive a plain fastener component engageable within the tubular component and of a length to occupy substantially the whole length of the interior of the tubular component, the cross-section of the plain fastener component being larger than the interior of the first portion of the tubular component and also larger at least than the narrower internal dimension of the further portion, the arrangement being such that, upon insertion of the plain fastener component, expansion of the tubular component will occur, such expansion being of greater extent over said further portion in the direction transverse to said plane of the slits, than over said first portion.

2. A fastener as claimed in Claim 1 in which the cross-sectional shape of the first portion of the tubular component is substantially circular, being made up of two semicircular portions and the cross-sectional shape of the further portion is substantially oblong, being made up of two generally U-shaped portions.

3. A fastener substantially as hereinbefore described with reference to and as shown in the accompanying drawings.