ONE PIECE PLASTIC CHAIR
A one piece integrally formed moulded plastic chair (11) is disclosed having a seat (2), backrest (3) and legs (4-7). A U-shaped rib (19) extends between the upper regions of the rear legs (6, 7) to cross-brace same. A gap (24) is proved between the cross piece (20) of the rib (19) and the underside of the seat (2). In use the seat (2) deforms to reduce the size of the gap (24) under the weight of a sitter. This deformation thereby provides a more comfortable seat.
Latest SEBEL FURNITURE LTD Patents:
The present invention relates to chairs and, in particular, to integrally moulded, one piece plastic chairs.
When plastic chairs were originally fabricated several decades ago, a plastic shell was moulded and this was screwed or otherwise connected to a steel frame which formed at least the legs of the chair. Such plastic shells did not include substantial reinforcing ribs and were thus relatively flexible. The metal legs were rigid and the shell could therefore flex relative to the frame and legs.
In more recent times, one piece chairs where the seat, backrest and legs of the chair are all simultaneously formed have also been produced. These are the chairs with which the present invention is concerned.
Such chairs are made by injection moulding and although the moulds for such chairs are very expensive, the individual chairs produced by such moulds are inexpensive and, if able to be sold in sufficiently large numbers, more than pays for the cost of the mould or tool. Educational institutions including schools and universities are a large market for such chairs. A prior art chair of this type is illustrated in
As seen in
The genesis of the present invention is a desire to provide an essentially similar chair to that of the chair 1 but in which the seat 2 exhibits some “give” or flexibility and so is able to deform under the weight of a sitter. This has the consequence that the seat 2 to some extent moulds itself to the shape of the sitter. This has the result that the chair is more comfortable for the sitter.
In accordance with a first aspect of the present invention there is disclosed an injection moulded one piece plastic chair comprising:
- a seat having a front region and a rear region, a pair of front legs, and a pair of rear legs;
- wherein said seat and legs are integrally connected to each other, the upper portions of said front legs are interconnected by a first rib which projects from the underside of said seat across substantially the width of said seat front region and provides a support for said seat front region and a cross-brace for said front legs; and
- the upper portions of said rear legs are connected by a second substantially U-shaped rib which is located below said seat rear region, which forms a cross-brace for said rear legs, which extends across substantially the width of said seat rear region, and which is connected with said seat only adjacent said rear legs, so that a first opening is formed between the underside of said seat and said second rib, whereby said rear region of said seat can flex toward said second rib under the load of the weight of a sitter
According to another aspect of the present invention there is provided a method of deforming the seat of a one piece integrally formed moulded plastics chair under load.
A preferred embodiment of the invention will now be described, with reference to the accompanying drawings in which:
In
However, as seen in
As seen in
Turning now to
An unexpected benefit of the above described construction is that since most of the rear rib 19 does not contact the under surface of the seat 2, there is less likelihood for the upper surface of the seat 2 to be blemished. Such blemishes are sometimes caused by the existence of an integrally formed rib under the surface of the seat 2 which can create differential rates of cooling of the moulded plastic.
Turning now to
For rib 19, the increase in stiffness is achieved by a single thickened region 25 which is preferably hollow. For rib profile 29 of
In
In
It will be appreciated by those skilled in the plastic moulding arts that the tool required to mould the chair of
The foregoing describes only some embodiments of the present invention and modifications, obvious to those skilled in the plastic moulding arts, can be made thereto without departing from the scope of the present invention.
The term “comprising” (and its grammatical variations) as used herein is used in the inclusive sense of “including” or “having” and not in the exclusive sense of “consisting only of”.
Claims
1. An injection moulded one piece plastic chair comprising:
- a seat having a front region and a rear region, a pair of front legs, and a pair of rear legs;
- wherein said seat and legs are integrally connected to each other,
- the upper portions of said front legs are interconnected by a first rib which projects from the underside of said seat across substantially the width of said seat front region and provides a support for said seat front region and a cross-brace for said front legs; and
- the upper portions of said rear legs are connected by a second substantially U-shaped rib which is located below said seat rear region, which forms a cross-brace for said rear legs, which extends across substantially the width of said seat rear region, and which is connected with said seat only adjacent said rear legs, so that a first opening is formed between the underside of said seat and said second rib,
- whereby said rear region of said seat can flex toward said second rib under the load of the weight of a sitter.
2. The chair as claimed in claim 1 wherein the second rib is shaped to have an increased stiffness relative to a planar rib moulded together with said seat.
3. The chair as claimed in claim 2 wherein said second rib has at least one portion of appreciable thickness in a front to rear direction relative to said seat.
4. The chair as claimed in claim 3 wherein said second rib is at least partially hollow.
5. The chair as claimed in claim 2 wherein said second rib has a cross-sectional shape which is bent or curved or kinked.
6. The chair as claimed in claim 1 and having a backrest extending upwardly from said seat rear region.
7. The chair as claimed in claim 6 and having a second opening between said backrest and said seat whereby said backrest can flex relative to said seat.
Type: Application
Filed: Nov 29, 2011
Publication Date: Oct 25, 2012
Applicant: SEBEL FURNITURE LTD (Padstow)
Inventor: Michael Andrew FEWCHUK (Eastwood)
Application Number: 13/305,925
International Classification: A47C 7/16 (20060101);