GB2063331A - Keying means for metal structures - Google Patents

Abstract

Keying means and a method and apparatus for the production of keying means in a sheet metal member 10 comprising an indentation 11 in the member defined by an elongate portion integral with the sheet member and joined to the remainder thereof only at the two longitudinal ends of the elongate portion, the portion being bent out of the plane of the remainder of the member, the apparatus for making the indentations 11 including a wheel 14 with peripheral lobes 15 and a support roller 16, the keying means being useful for plastering or attachment of nails. <IMAGE>

Description

SPECIFICATION Keying means for metal structures This invention relates to means for keying onto metal structures, either plaster or solid members such as wooden battens.

In one example, a sheet metal lintel requires a plaster keying means to enable plaster cover to be attached to vertical or even underneath horizontal surface.

There are a number of plaster key means already in existence, one of the most common being expanded metal mesh which is secured to the lintel or other metal structure by welding at spaced positions. This provides a quite satisfactory key for the plaster but required a separate operation to weld it to the metal structure usually after this has itself been assembled. There have been several proposals for treating or otherwise working the metal including cutting and shaping, but many of these arrangements do not provide a good plaster key, often because the plaster will not readily enter interstices or openings intended for that purpose. Many of these proposals however are expensive to produce.

It may also or alternatively be required to attach solid members to the metal structure. Again, in the example of a metal lintel, the attachment of a wooden batten prior to overplastering is quite common, so that curtain rails or other fixtures can be fixed to the wooden batten, thus obviating the need for drilling of the lintel. The attachment of such wooden battens usually takes place after the lintel is installed but before plastering and conventionally it is attached by screws, nails or bolts passing through drillings made in the lintel individually for the purpose.

The object of this invention is to provide a keying means on metal structures which is efficient in affording a suitable surface to which plaster will key and to which solid members may be conveniently applied and which is inexpensive to produce.

According to one aspect of the invention there is provided a keying means in a sheet metal member comprising an indentation in the member defined by an elongated portion integral with the member and joined to the remainder of the member only at the two longitudinal ends thereof, the said portion being bent out of the plane of the adjacent region of the said member.

According to a further aspect of the invention a method for forming keying means in a sheet metal member comprises cutting the sheet metal member in two spaced generally parallel positions and bending the intervening longitudinal portion out of the plane of the adjacent region of the said member, to form an indentation.

According to a still further aspect of the invention there is provided apparatus for forming keying means in a sheet metal member including a rotatable cutter wheel with at least one cutting lobe, arranged for cutting the sheet metal in two spaced generally parallel positions and for bending the intervening longitudinal portion out of plane of the adjacent region of the member, to form an indentation in the member.

Preferably this apparatus also has a support roller which supports the sheet metal member as the lobe makes the cuts and bends the sheet metal member.

The invention will now be described, by way of example with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of a steel sheet member having plaster keying means formed therein.

Figure 2 shows apparatus for making plaster keying means in a sheet metal member, Figure 3 is a side elevation view of the apparatus in Figure 2.

Figure 4 is a view of a nail for use in the keying means, Figure 5 is a perspective view of a metal lintel with keying means and showing the fitting of the nail in Figure 4.

Figure 6 is a similar view to Figure 5 with the nail shown in place, Figure 7 is an enlarged view of a plastics insert, Figure 8 shows the same insert being fitted into a keying means.

Figure 9 is a view of the same insert with a nail engaged in it and Figure 10 is a perspective view of a metal lintel showing one nail fitted in keying means therein.

Referring first to Figure 2, this shows a sheet metal member indicated generally at 10 which is intended for use as part of a sheet metal lintel. It may be of any required width and length and may be in the form of a strip suitable for construction of one component of a sheet metal lintel or alternatively it may be a continuous strip which is afterwards cut to the appropriate length.

The sheet is shown being formed with a number of indentations in its surface to form plaster key means. Figure 1 shows clearly one of such indentations, having been deformed from the flat surface of the sheet 10 to define a parallel sided concave recess 11 at one side of the sheet.

This produces corresponding convexity on the other side of the sheet. Conveniently, each such recess 11 may have a length of 10 mm and may have a depth such that there is a gap between the underneath surface of the sheet 10 and the base of the recess 11 having a depth of 2 mm.

Indentations of other proportions may, however, be used.

Each indentation is formed by cutting the sheet 10 over the appropriate length in two parallel lines, to form the indentation. The metal between these cuts is bent to form the recess 11 as shown in Figure 1. The depth of the recess is greater than the thickness of the sheet, as shown.

Figure 2 shows the sheet 10 having a number of spaced indentations arranged in parallel lines. In the examples shown, there are three parallel lines of such indentations, the spacing of the lines and the spacing of the individual indentations being approximately 10 cm.

The apparatus shown in Figure 2, for producing the indentations comprises two parallel shafts 12 and 13. The shaft 12 carries, in this example, three spaced disc wheels 14, each with spaced peripheral lobes 15. The spacing of the lobes 1 5 is equal to the desired spacing of the indentations in the sheet 10. The number of the lobes is dependant upon indentation spacing in relation to disc diameter and any number including only one lobe may be provided.

The shaft 1 3 carries a roller 1 6 (seen in Figure 3) which provides support for the sheet 10 as it is fed through the apparatus. The roller 16 has grooves or other formations to accommodate metal bent by the oboes 1 5 out of the plane of the sheet 10.

Either or both of the shafts 12 and 13 are driven from a suitable power source and rotation thereof produces advance of the sheet 10 as well as formation of the indentations. The lobes 15 of the discs 14 have flat sides to provide the cutting edges whereby the two parallel cuts are formed simultaneously with the bending of the metal sheet 10 to form the indentations. Adjustment of the positions of the shafts may be carried out to control the depths of the indentations as required.

The machine may be fed with a series of cut length sheets or with continuous strip material in a lintel, the positions of the indentations in relation to the ends of strip lengths is immaterial.

The form of the lobes 15 may be varied to provide other shapes of indentations in the sheet.

The bending of the sheet which takes place is within the limits of deformation of the sheet without significant risk of cracking or breaking of the metal.

A complete lintel incorporating components formed with the plaster keying means may have a plaster layer laid upon it. Plaster on the surface formed with the indentations will tend to fill the recesses and will penetrate through the gap formed between the base of each recess and the adjacent underneath surface of the sheet. After hardening this will provide keying to retain the plaster in place.

In certain circumstances it may be necessary to attach a structure such as a wooden batten to a metal lintel. For example where the lintel is used above a doorway the wooden batten is useful for attachment of curtain rails or other fixtures the use of such a wooden batten avoiding the necessity for drilling through the sheet metal lintel itself. The wooden batten is usually attached before plastering takes place and plaster is applied over the whole of the lintel and including the wooden batten.

The plaster keying means already described can be used for the convenient attachment of a wooden batten in the manner to be described. The form shown in Figures 4, 5 and 6 employs a special nail which can be fitted into any one of the keying indentations. Figure 4 shows such a special nai. 18. It is pressed from sheet metal and has a tapered shank and a head having a curved end surface 19 and a pair of inclined shoulders 21. The curvature of the end surface 1 9 corresponds with the curvature of the interior of one of the indentations 11. Figure 5 shows the nail 1 8 being fitted into an indentation 11 in a sheet metal lintel 22. The nail is first placed in the indentation with its head extending lengthwise of such indentation.

The shank is then grasped by means for example of a pair of pliers 23 and the nail is rotated through 900. The ends of the head pass into the spaces between the rear flat face of the sheet metal and the base of the indentation. The inclined shoulders 21 on the nail 1 8 serve to lock the nail very tightly into position. Figure 6 shows the nail in place and extending out of the lintel perpendicularly to the surface. A wooden batten can be driven directly on to this by hammer blows and the end of the nail which may protrude through the batten can be bent over to lock the batten firmly in place. This arrangement is convenient in that nails can be fitted at any position on the lintel after the latter has been assembled into a wall or other structure.

Figures 7 to 10 show an alternative nail arrangement which involves the use of a plastics insert 23 which is shown in Figure 7. This is a small rectangular part with tapered end flanges 24 at its opposite ends and a central opening 25 communicating with one side of the insert through a slot 28. Surrounding the central opening 27 at one side of the insert is a shallow platform 29 and at the other side is a shallow recess 31.

Figure 8 shows the insert located in the base of one of the indentations 11 in a sheet metal structure. A screwdriver indicated at 32 is engaged in the slot 28 and in the central opening 27 of the insert and the insert is then rotated to the position shown in Figure 9. The tapered flanges at the ends of the insert facilitate entry of the ends of the insert into the spaces between the flat rear face of the sheet metal and the base of the indentation and they also serve to lock it in place when rotated through 900 to the position shown.

The recess 31 on the face of the insert has a width equal to the base of the indentation so that the position shown in Figure 9 is maintained.

A standard nail 33 with a flat head and cylindrical pointed ended shank is fitted into the insert by passing the shank through the slot 28 and into the central opening 27. The head of the nail 33 rests against the base of the indentation to prevent any significant movement of the nail and the slot 28 has a width rather less than the shank of the nail so that the latter can be forced into the central opening 27 but resistance is offered to its removal.

Figure 10 shows a metal lintel 34 mounted in a wall 35 and a single nail 33 of the type shown in Figure 9 and ready for the direct application of a wooden batten in the manner described in relation to the construction of Figures 4, 5 and 6.

Claims (20)

1. A keying means in a sheet metal member comprising an indentation in the member defined by an eiongated portion integral with the member and joined to the remainder of the member only at the two longitudinal ends thereof, the said portion being bent out of the plane of the adjacent region of the said member

2. A keying means as claimed in claim 1 in which the said portion has a concave base surface which is spaced from the face of the remainder of the sheet towards which the portion is bent to define respective spaces between said base surface and said face.

3. A keying means as claimed in claim 1 or claim 2 in which the indentations are formed at spaced positions on the metal member.

4. A keying means as claimed in any one of the preceding claims in which a nail is engaged in the indentation, for attachment in use of a member to the face of the sheet metal member.

5. A keying means as claimed in claim 4 in which the nail has a head wider than the indentation and shaped to locate in spaces defined at the sides of the indentation whereby the nail head extends transversely of the length thereof.

6. A keying means as claimed in claim 5 wherein the nail head has shoulders to lock the nail in the said spaces, at the sides of the indentations the head also having end surface which in use engages a base surface of the indentation.

7. A keying means as claimed in any one of claims 4 to 6 in which the nail is made from flat sheet metal.

8. A keying means as claimed in any one of claims 1 to 3 wherein a nail is engaged in an insert located in the indentation.

9. A keying means as claimed in claim 8 wherein the insert is engaged in spaces defined at the sides of the indentation to extend transversely of the length of the indentation.

10. A keying means as claimed in claim 9 wherein the head of the nail engages between the insert and a base surface of the indentation.

11. A method of forming keying means in a sheet metal member comprising cutting the sheet metal member in two spaced generally parallel positions and bending the intervening longitudinal portion out of the plane of the adjacent region of the said member, to form an indentation.

12. A method as claimed in claim 11 wherein a plurality of the indentations are formed in the sheet at spaced positions therein.

13. Apparatus for forming keying means in a sheet metal member including a rotatable cutter wheel with at least one cutting lobe, arranged for cutting the sheet metal in two spaced generally parallel positions and for bending the intervening longitudinal portion out of plane of the adjacent region of the member, to form an indentation in the member.

14. Apparatus as claimed in claim 13 wherein a support roller is arranged to support the sheet metal member as the lobe makes the cuts and bends the sheet metal member.

1 5. Apparatus as claimed in claim 14 wherein the support roller has a groove to accommodate the displaced portion of the sheet metal member as it is bent by the cutter wheel lobe.

1 6. Apparatus as claimed in any one of claims 13 to 1 5 wherein the cutter wheel has a number of lobes.

1 7. Apparatus as claimed in any one of claims 13 to 1 6 wherein there are a number of cutter wheels arranged to produce lines of parallel indentations in the sheet metal member as it is advanced to the wheels.

1 8. A keying means substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

19. A method for forming keying means substantially as hereinbefore described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

20. Apparatus for forming keying means substantially as hereinbefore described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.