GB2035894A - Shaped structural element of laminated construction - Google Patents

Abstract

A construction of structural element comprises a substrate 10 of moulded plastics having a surface which has a major planar portion 12 and a further portion 13 which extends from and out of the plane of the first portion to provide a radiused edge to the element. A laminate e.g. a surface layer 14 and a backing layer 15 is bonded to the substrate surface. The substrate may be moulded to include means for securing elements together and for securing fittings to the element e.g. in the manufacture of furniture such as tables. The free surface of the substrate may comprise ribs which may be reinforced. <IMAGE>

Description

SPECIFICATION Structural elements BACKGROUND OF THE INVENTION This invention relates to structural elements such as panel-like members for use in the construction of furniture.

It has been proposed to form panel-like table tops and work tops for furniture utilising a substrate of wood or wood composite, such as chipboard, and to provide a durable and decorative surface by securing a laminate to the substrate.

However such construction is usually unacceptable in industrial enviroments and for use in the construction of computer equipment because it is not flame retardant. Also the manufacturing process requires a number of manual operations to shape the substrate to the desired form and to bond the laminate to the substrate. In addition, it is desired to secure the panel to other members, for example to another panel or to legs, it is necessary to provide additional means to effect the assembly.

SUMMARY OF THE INVENTION According to the invention a structural element includes a substrate of moulded plastics material having a surface said surface including a first planar portion and a second portion extending from said first planar portion out of the plane of the first portion; and a continuous surface layer bonded to both said first and second portions of said surface.

If desired the substrate may have means moulded thereon to enable the attachment of another structural element to said element.

Also means may be moulded on the substrate to enable the structural element to be secured to another member.

BRIEF DESCRIPTION OF THE DRAWINGS Constructions of panel members embodying the invention will now be described, by way of example, with reference to the accompanying-drawings in which: Figure 1 shows a cross-section of a panel; Figure 2 shows a partial cross section of a panel and illustrates alternative forms of devices for ensuring a strong bond between a laminate and it's substrate: Figures 3a and 3b are partial cross section and underneath plan views respectively of a table top with a leg secured thereto.

Figure 4 is a partial cross section view of a further method of securing a leg to a table top; Figure 5 is an underneath plan view of another method of securing a leg to a table top; Figure 6 and 6b are partial cross section and underneath plan views respectively of another method of securing a leg to a table top; Figure 7 shows an exploded view of an assembly of panels; Figures 8 and 9 are partial cross section views showing alternative means for joining two panels and for securing edging trim; DESCRIPTION OF PREFERRED EMBODI MENTS Referring to Fig. 1, a panel member consists of a rigid substrate 10 formed as a moulding of plastics material, to which is bonded a continuous sheet of laminate 11.

The substrate 10 has a surface of which a major portion 12 is substantially planar, and at least one edge 13 of the substrate is rounded. The laminate consists of a surface layer 14 of plastic and a backing layer 15.

The laminate is chosen to provide a required properties of durability and/or decoration.

The surface of the substrate 10 may be treated chemically and/or mechanically to provide keying to facilitate the bonding of the laminate 11 to the substrate 10 by means of conventional adhesives. The lower face of the substrate 10 may be provided with ribs 16 to increase the structural strength of the panel and to give increased rigidity to the panel.

Since the substrate is formed as a moulding, the desired profile of the surface to which the laminate is to be bonded and the required ribs are formed in the moulding operation.

Instead of bonding the laminate 11 to a previously moulded substrate 10 the substrate 10 may be formed by moulding in situ on the rear face of the laminate 11. This method of moulding the substrate is described in UK patent applications Nos. 19684/78, 29177/78 and 29178/78. When this method of moulding the substrate is used, means shown in Fig. 2 may be provided to ensure that the laminate 11 is securely bonded to the substrate. For example studs 17 may be bonded by adhesive or with suitable laminates, by welding to the backing layer 15. Alternatively members 18, 19 of extruded T or L section may be used, the webs of the members being formed to provide a good mechanical fixture in the substrate 10.

Clearly a combination of such means may be used, the studs 17 and or members 18, 19 being provided at positions where the bond between the laminate and the substrate is subject to high stress, for example adjacent exposed edges of the laminate.

If desired reinforcing members 20 may be provided in the ribs 16. The members 20 are of a material having greater strength than the plastic moulding of the substrate 10. The members 20 are embedded in the substrate in the formation of the substrate by moulding.

Various forms of reinforcing members are described in pending UK application No.

29178/78.

Plastics materials suitable for forming the substrate are foam resins such as rigid polyurethane, polystyrene, polypropylene, polyethylene and those marketed under the trade names of "Noryl" and "Lexan".

The laminate sheet may be melamine faced with a backing layer of synthetic resin bonded paper such as those known as "Formica" and "Warerite"; or PVC faced with a backing layer of aluminium such as that known as "Bon dene"; or PVC faced with a backing layer of steel such as that known as "Stelvetite".

Figs. 3a and 3b show a method of fixing a leg 21 to a panel 22 forming a table top. The leg 21 is of rectangular section and its upper end engages in a socket 23 of similar rectangular section formed in the moulded substrate 24. If desired the socket may be tapered along its length and the upper portion of the leg tapered to fit securely in the socket.

Instead of a rectangular section leg, the leg may be of L section in which case the socket 23 is formed of similar rectangular section formed in the moulded substrate 24. If desired the socket may be tapered along its length and the upper portion of the leg ta: pered to fit securely in the socket.

Instead of a rectangular section leg, the leg may be of L section in which case the socket 23 is formed of similar section. Clearly legs of various sections, which may be solid or hollow, may be used, the socket being formed of a corresponding section to receive the upper end of the leg.

When the leg is of hollow section, instead of a socket in the substrate, a spigot 25 (Fig.

4) may be provided on the substrate to engage in the upper end of a leg 26.

In Figs. 5, 6a and 6b, the leg is fastened to a part of the substrate by means of a screw fastening. In the construction shown in Fig. 5 a spigot 27 is provided on the lower face of the substrate and an L section leg 28 is secured to the spigot by a screw fastening 29.

In the construction shown in Figs. 6a and 6b the leg 30 is secured to a web 31 on the underside of the substrate by means of a screw stud 32. Preferably the web 31 is formed to engage the section of the leg so that the leg is prevented from moving relative to the substrate.

Fig. 6 shows a method of interconnecting panels to form an item of furniture. A table top 33 is formed with a stopped groove 34 of dovetail section in a lower face of the substrate 35. A side panel 36 is formed with a rib 37, of similar dovetail section, on its upper edge to engage in the dovetail groove 34 and thereby secured the table top 33 and the side panel 36 together. Additional rigidity may be provided by a bracket 38 on the side panel moulding which is secured to the table top by means of a screw 39. If desired the bracket may be provided with a dovetail projection to engage in a further dovetail groove in the table top instead of using the screw 39.

Grooves 40 are provided in the side panel 36 to receive drawers or shelves.

Although the side panel 36 is shown as being a solid panel it may be of skeleton form so as to provide a pair of legs joined by one or more cross members.

A pair of panels 45, 46 may be secured together in edge-wise abutment with the laminates in alignment by forming grooves 41 in webs 42, located adjacent the edges of the panels, and providing a member 43 to engage in both grooves 41 and thereby locate the panels relation to one another. The panels may be secured together by means of bolts 44 passing through the webs 42 and nuts 45. Free edges of the panels may be provided with edge trim 47 consisting of a strip of material of desired profile and formed with a rib 48 engaging in the groove 41. Threaded studs 49 project from the rib 48 to enable the trim 47 to be secured by nuts 50 to the web 42.

Instead of providing grooves 41 of rectangular section in the webs, the grooves may have a different section. For example as shown in Fig. 9 grooves 51 of dovetail section are formed in the panels 52 and a joining member 53 of double dovetail section is provided to engage in both grooves 51. The joining member 53 therefore serves to secure the panels together as well as to maintain them in alignment and hence no additional securing means is required. An edge trim 54 with a dovetail rib 55 engaging in the groove 51 may be provided.

If it is found that the substrate suffers distortion after moulding due to differential shrinkage of various portions of the substrate so that, for example, the surface, which is required to be substantially planar would acquire a converse form, the substrate is moulded in such a manner that the surface is concave. The concavity is chosen so that after the distortion has taken place, the surface has the required planar form. This method is described in more detail in our co-pending UK patent application No. 29177/78.

Claims (13)

1. A structural element includes a substrate of moulded plastics material having a surface; said surface including a first planar portion and a second portion extending from said first planar portion out of the plane of the first portion; and a continuous surface layer bonded to both said first and second portions of said surface.

2. An element as claimed in Claim 1 in which the substrate is provided with ribs integrally moulded therewith effective to resist bending of the substrate.

3. An element as claimed in Claim 1 or 2 in which the substrate is provided with means integrally moulded therewith to enable the elements to be secured to a member.

4. An element as claimed in Claim 3 in which said means has a recess therein to receive a projection on the member.

5. An element as claimed in Claim 3 in which said means includes a spigot operative to engage in a recess in the member.

6. An element as claimed in any preceding claim in which the substrate of said element is provided with first means integrally moulded therewith operative to engage with second means integrally moulded with a substrate of a further structural element.

7. An element as claimed in any preceding claim in which the substrate includes stabilising means embedded therein effective to resist distortion of the element due to differential shrinkage of the substrate.

8. A structural element constructed substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

9. A structural element constructed substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

10. A structural element constructed substantially as hereinbefore described with reference to Figs. 3a and 3b, 4, 5 or 6a and 6b, of the accompanying drawings.

11. A structural element constructed substantially as hereinbefore described with reference to Fig. 7, of the accompanying drawings.

12. A structural element constructed substantially as hereinbefore described with reference to Fig. 8, of the accompanying drawings.

13. A structural element constructed substantially as hereinbefore described with reference to Fig. 9, of the accompanying drawings.