WO2014202943A1

WO2014202943A1 - Plastics jointing system

Info

Publication number: WO2014202943A1
Application number: PCT/GB2014/051076
Authority: WO
Inventors: David Glover
Original assignee: Certwood Ltd
Priority date: 2013-06-21
Filing date: 2014-04-07
Publication date: 2014-12-24
Also published as: EP3010375B1; GB201311063D0; EP3010375A1

Abstract

A plastics jointing system comprises a first structure and a second structure that is joined to the first structure, wherein the first structure and the second structure are each unitary moulded plastics structures. The first structure includes a first connecting structure and the second structure includes a second connecting structure, the first and second connecting structures each having complementary locking formations that are engageable to connect the first structure to the second structure.

Description

Plastics Jointing System

The present invention relates to a plastics jointing system and to a moulded plastics article. In particular but not exclusively the invention relates to an article of furniture, for example a moulded plastics chair or similar item.

Stackable chairs that have an injection moulded plastics seat attached to a steel leg structure are well known. The leg structure is usually attached to the underside of the moulded plastics seat using a set of screws, bolts or clips. Such seats are generally lightweight and relatively inexpensive, making them suitable for use in schools, meeting halls and similar establishments.

The stackable chairs described above have a number of significant disadvantages. First, the connection between the seat and the steel leg structure can be quite weak and may break if subjected to excessive force. As a result such seats may have a relatively short lifespan. The plastics seat is also generally rather flexible and can deform if it is not well supported by the steel leg structure. The steel leg structure can also be damaged by rust if the chair is used outdoors and the protective coating on the leg structure (for example chromium plating or paint) is damaged. Such chairs also frequently lack aesthetic appeal as the leg structure does not harmonise well with the appearance of the moulded plastics seat.

It is also known to manufacture plastics chairs as monobloc or unitary plastics mouldings comprising the seat and the legs. Such chairs are often designed for use as garden or patio chairs as they are generally weather-proof. However, they tend to be rather flexible and unstable in use. Also, manufacturing an entire chair as a monobloc moulding requires a very large mould, which is consequently very expensive. It is an object of the present invention to provide an article of furniture, for example a moulded plastics chair, that mitigates one or more of the aforesaid disadvantages. A further object of the invention is to provide a plastics jointing system.

According to one aspect of the present invention there is provided an article of furniture comprising a support structure and an upper structure that is supported by the support structure, wherein the support structure and the upper structure are each unitary moulded plastic structures, the upper structure including an upper connecting structure and the support structure including a lower connecting structure, the upper and lower connecting structures each having complementary locking formations that are engageable to connect the leg structure to the upper structure.

The invention provides a number of significant advantages. First, the connection between the upper structure and the support structure is very strong and the article of furniture can therefore be expected to have a relatively long lifespan. The article of furniture is also very rigid and will not deform significantly in normal use. As the article is made substantially or entirely of plastics materials it will be weatherproof and will not be damaged by rust if the chair is used outdoors, and does not require a protective coating. The article of furniture can have an aesthetically pleasing appearance as the support structure matches the appearance of the moulded plastics upper structure. It is also possible to provide a range of upper and support structures that can be connected in different combinations. This makes it possible to supply a wide range of articles with different appearances and properties. For example, it is possible to provide a range of chairs that have different appearances, heights, backrest types, colour combinations, leg types and so on. Accessories such as arm rests or tablet computer supports may also be attached using similar connecting structures. Further, because the upper structure and the support structure are moulded separately, the moulds can be much smaller than if the article was manufactured as a monobloc moulding, thus reducing substantially the cost of the mould.

Advantageously, the article of furniture comprises a chair or stool and the upper structure comprises a seat.

Advantageously, the article of furniture includes at least two leg structures that are attached on opposite sides of the seat. Alternative support structures may be provided including for example a telescopic column on a star base, or a plurality of seats may be attached to a supporting beam.

Advantageously, the upper connecting structures are provided on a lower side of the seat.

Advantageously, the lower connecting structures extend inwards from the leg structures beneath the seat.

Advantageously, each leg structure includes a pair of legs and a bridging structure that interconnects the legs, wherein the lower connecting structure extends inwards from the bridging structure.

Advantageously, the complementary locking formations include one or more dovetail formations.

Advantageously, the complementary locking formations include a peripheral wall member.

Advantageously, the complementary locking formations include one or more resilient locking elements.

Advantageously, the article of furniture includes a plurality of fastening elements for fastening the or each support structure to the upper structure.

Advantageously, the or each support structure and the upper structure each comprise a unitary plastics moulding that is manufactured by a gas injection moulding process.

Advantageously, the support structure comprises at least one leg structure.

Advantageously, the article of furniture comprises a chair that is optionally stackable with similar chairs.

According to another aspect of the invention there is provided a plastics jointing system comprising a first structure and a second structure that is joined to the first structure, wherein the first structure and the second structure are each unitary moulded plastics structures, the first structure including a first connecting structure and the second structure including a second connecting structure, the first and second connecting structures each having complementary locking formations that are engageable to connect the first structure to the second structure.

Advantageously, the complementary locking formations include one or more dovetail formations. Advantageously, the complementary locking formations include a peripheral wall member.

Advantageously, the plastics jointing system includes a plurality of fastening elements for fastening the first structure to the second structure. Advantageously, the first structure and the second structure each comprise a unitary plastics moulding that is manufactured by a gas injection moulding process.

An embodiment of the present invention will now be described with reference to the accompanying drawings wherein:

Figure 1 is an isometric view of a chair according to an embodiment of the invention seen mainly from the front;

Figure 2 is an isometric view of the chair seen mainly from the right-hand side;

Figure 3 is a side view of the chair from the left-hand side, with the seat separated from the leg structures;

Figure 4 is an isometric view of the chair mainly from the left-hand side, with the seat separated from the leg structures;

Figure 5 is an isometric view of the chair seen from below and from the front, with the seat separated from the leg structures;

Figure 6 is an isometric view of the chair from beneath and from the rear, with the seat separated from the leg structures; Figure 7 is a partial isometric view of the chair with the seat separated from the leg structures, showing the seat from below and the leg structures from above;

Figure 8 is similar to Figure 7 and shows part of the seat and one of the leg structures at an enlarged scale, and Figure 9 is a side view showing part of the assembled chair, partially in cross-section.

The chair 2 shown in the drawings includes an upper structure comprising a seat 4 and a support structure comprising two leg structures 6, wherein the seat 4 and each of the leg structures 6 comprise unitary or monobloc plastics mouldings. The seat 4 and the leg structures 6 each have complementary connecting structures 8, 10 respectively, which permit the seat 4 to be attached rigidly to the leg structures 6. Optionally, metal or plastics fastening screws 12 may be provided to increase the strength of the joints between the leg structures 6 and the seat 4.

In this embodiment the seat 4 comprises a base 14 and an upright backrest 16. A peripheral rim 18 extends around the edges of the base 14 and the backrest 16 to help support the backrest 16 and increase the rigidity of the seat 4. The strength and rigidity of the seat 4 may be increased further by the provision of a thickened region 20 on the lower surface of the base 14 and the rear surface of the backrest 16. The seat connecting structures 8 are provided on the underside of the base 14.

The leg structures 6 each include two curved legs 22 that are connected at their upper ends to a substantially horizontal bridging portion 24. The leg connecting structure 10 of each leg structure 6 is provided on the upper surface of a support plate 26 that extends substantially horizontally inwards from the bridging portion 24.

The seat connecting structure 8 and the leg connecting structures 10 have complementary locking formations that allow the leg structure 6 to be attached rigidly to the seat 4. On each seat connecting structure 8 these locking formations include a peripheral wall 28, which comprises an extension of the peripheral rim 18 but is displaced inwards from the side edge 30 of the seat 4 so that it extends beneath the base 14. The other locking formations making up the seat connecting structure 8 are located in the space between the peripheral wall 28 and the side edge 30, on the underside of the base 14. These locking formations include one or more dovetail or trapezoidal formations 32, a longitudinal dividing wall 34, a plurality of ribs 36 and four buttressed cylindrical tubes 38 for receiving the fastening screws 12. The leg connecting structures 10 have equivalent locking formations, including a peripheral wall 40, dovetail or trapezoidal formations 42 and cylindrical tubes 46 for receiving the fastening screws 12.

When the chair 2 is assembled the locking formations making up the seat connecting structures 8 and the leg connecting structures 10 fit together providing a strong and rigid connection between the seat 4 and the leg structures 6. In this embodiment the locking formations are designed to lock together by relative movement of the seat 4 and the leg structures 6 in a vertical direction (assuming that the chair is upright). The seat 4 and the leg structures 6 are then fastened together by driving fastening screws 12 through the tubes 46 in the leg structures 6 into engagement with the tubes 38 in the seat 4. Alternatively, or in addition, the locking formations may include locking elements, for example deformable detents, that click into engagement to attach the leg structures 6 permanently to the seat 4 when the chair 2 is assembled. These locking elements may be provided instead of, or in addition to, the fastening screws 12.

Optionally, stacking supports 50 may be provided on the inner faces of the legs 22. When a plurality of chairs 2 are stacked these stacking elements rest on the seat 4 of a supporting chair, to facilitate neat stacking of the chairs. The moulded plastics components of the chair are preferably made using a gas assisted injection moulding process, which provides great strength to the moulded product. Alternatively, a conventional injection moulding process may be used. The plastics material is preferably polypropylene, although any other suitable plastics material may also be used. Various modifications to the moulded chair described herein are of course possible. For example, the chair may be provided with arms and/or a desk or tablet computer support that are connected to the underside of the seat using connecting structures similar to those provided for connecting the leg structures. The leg structures may be replaced by alternative support structures. For example, a bridge connection may be provided that spans the joints beneath the seat, and that has a socket for receiving a telescopic column mounted on a conventional wheeled star base, allowing the seat to be used as a conventional height-adjustable office chair. Alternatively, a plurality of seats may be attached to a support beam for a beam seating system.

Although the invention has been described particularly with reference to a lightweight stackable chair, it should be understood that the invention is also applicable to other articles including, for example, stools and tables. The present invention also extends more broadly to a plastics jointing system comprising connecting structures similar to the seat connecting structure 8 and the leg connecting structure 10 described herein.

Claims

1. An article of furniture comprising a support structure and an upper structure that is supported by the support structure, wherein the support structure and the upper structure are each unitary moulded plastics structures, the upper structure including an upper connecting structure and the support structure including a lower connecting structure, the upper and lower connecting structures each having complementary locking formations that are engageable to connect the support structure to the upper structure.

2. An article of furniture according to claim 1, wherein the article of furniture comprises a chair or stool and the upper structure comprises a seat.

3. An article of furniture according to claim 2, wherein the support structure includes at least two leg structures that are attached on opposite sides of the seat.

4. An article of furniture according to claim 3, wherein the upper connecting structures are provided on a lower side of the seat.

5. An article of furniture according to claim 4, wherein the lower connecting structures extend inwards from the leg structures beneath the seat.

6. An article of furniture according to any one of claims 3-5, wherein each leg structure includes a pair of legs and a bridging structure that interconnects the legs, and wherein the lower connecting structure extends inwards from the bridging structure.

7. An article of furniture according to any one of the preceding claims, wherein the complementary locking formations include one or more dovetail formations.

8. An article of furniture according to any one of the preceding claims, wherein the complementary locking formations include a peripheral wall member.

9. An article of furniture according to any one of the preceding claims, wherein the complementary locking formations include one or more resilient locking elements.

10. An article of furniture according to any one of the preceding claims, including a plurality of fastening elements for fastening the support structure to the upper structure.

11. An article of furniture according to any one of the preceding claims, wherein the support structure and the upper structure each comprise a unitary plastics moulding that is manufactured by a gas injection moulding process.

12. An article of furniture according to any one of the preceding claims, wherein the support structure comprises at least one leg structure.

13. An article of furniture according to any of the preceding claims, wherein the article of furniture comprises a chair that is optionally stackable with similar chairs.

14. A plastics jointing system comprising a first structure and a second structure that is joined to the first structure, wherein the first structure and the second structure are each unitary moulded plastics structures, the first structure including a first connecting structure and the second structure including a second connecting structure, the first and second connecting structures each having complementary locking formations that are engageable to connect the first structure to the second structure.

15. A plastics jointing system according to claim 13, wherein the complementary locking formations include one or more dovetail formations.

16. A plastics jointing system according to claim 13 or claim 14, wherein the complementary locking formations include a peripheral wall member.

17. A plastics jointing system according to any of claims 13 to 15, wherein the complementary locking formations include one or more resilient locking elements.

18. A plastics jointing system according to any of claims 13 to 16, including a plurality of fastening elements for fastening the first structure to the second structure.

19. A plastics jointing system according to any of the preceding claims, wherein the first structure and the second structure each comprise a unitary plastics moulding that is manufactured by a gas injection moulding process.

20. A moulded plastics article comprising a first structure and a second structure that is joined to the first structure, wherein the first structure and the second structure are each unitary moulded plastics structures, the first structure including a first connecting structure and the second structure including a second connecting structure, the first and second connecting structures each having complementary locking formations that are engageable to connect the first structure to the second structure.