Furniture

Abstract

An item of wooden furniture, such as a chair or stool, with a horizontal portion (10), such as the seat, supported by multiple legs (11-14); at least one of the legs is formed from two elongate member

Description

pg. 1 FURNITURE Field of the Invention This invention relates to furniture, and in particular to items of wooden furniture that are supported by legs, and to the mean whereby the legs are fixed to the remainder of the item. Background of the Invention English Windsor chairs have a thick wooden seat so that the legs can be round tenoned and wedged into them. Stretchers (horizontal rails) are situated between the legs and push them apart. This puts the legs under stress and reduces slack. Each leg of a Windsor chair is one straight element (turned to be cylindrical) and does not noticeably flex. Elements of the Windsor chair are sometimes steam bent to form curves: the “bow” back and the armrests. Bentwood furniture has curved elements which are traditionally produced by steam bending. Michael Thonet was the first to industrialise the process for furniture. Steam bending uses heat and moisture to soften the wood fibres so it is pliable enough to be bent. It is held in its bent form whilst it dries so it holds the new shape. This was structurally, economically and ecologically sounder than shaping a bigger piece of wood into a curve. To some degree, steam bending weakens the wood through the processes of heat and moisture. Green bending wood was a traditional process whereby elements of a chair where cut from green (unseasoned) wood, bent and then dried in an oven or allowed to air dry naturally in position to hold the curved form. Green wood has a high moisture content which allows it to be bent beyond its proportional limit. This process was sometimes used for the back legs of Philip Clissett Ladderback chairs or the shaping of back spindles for Windsor chairs. Laminating is a process which involves bending dry, thin veneers which have been seasoned, into a curve and gluing them together. Each glued veneer holds the other into the shape. Because the smaller thicknesses of veneers can be easily bent cold without added moisture, a much thicker curved section can be built up than otherwise possible. All these methods of bending will create curved elements in furniture that will not revert to their former shape (except some small spring-back) once dry. Pg. 2 Summary of the Invention According to the present invention, an item of wooden furniture comprising an essentially horizontal member and legs supporting said member, wherein at least one leg bifurcates upwardly and its upper ends are held in stress by being fixed to the said member. Preferred features of the invention are defined in the subclaims. The invention is of particular utility in chairs. The invention offers these advantages: Because the components of the invention have not been made pliable by heat or moisture, the wood maintains all its elasticity and strength: allowing for smaller components, reducing material cost. Because the components are straight before fitting into the seat, and will return to straightness if removed, when they are forced apart at the top they are put into stress (stress being advantageous here). Because each cold-bent leg component mutually stresses the other, the leg as a whole becomes stiffer allowing for the exclusion of an undercarriage or stretchers between each leg. It also helps secure the leg into the seat joint. Because there are no rails or undercarriage holding the legs totally rigid, they can individually splay when underload. This means that when saton, allfourlegs can individually flex to make contact with the floor: which means the chair does not rock on moderately uneven floors. Forcing the components apart at the top and restraining them at the base provides aesthetically pleasing organic curves to the leg with no additional processes like laminating or steaming: meaning quicker production and lower manufacturing costs. Description of the Drawings The invention will be described by way of example only with reference to the accompanying drawings. Figure 1 is a perspective view of a chair that embodies the invention. Figure 2 is a view of a leg for use in the invention. Fig. 1 shows a chair having a seat 10, front legs 11 and 12, rear legs 13 and 14, and a chair back comprising an outer band 15 and a central panel 16. In this embodiment, the panel 16 is stressed by its fixed attachment to the seat 10 and the outer band 15. Each of the front legs 11 and 12 comprises two parts (11a, 11b, 12a, 12b) that are fixed to each other towards their lower ends and bent so that they bifurcate. The bifurcation is held in stress by the fixing of the upper ends of the leg parts in corresponding recesses in the seat 10. Fig. 2 shows the two parts of a leg to be used in the embodiment of Fig. 1. Fig. 2a shows the two parts before jointing. Fig. 2b shows the leg components jointed with dominos and bolted together. This is the natural, unstressed configuration of the leg when not forced apart. Fig. 2c shows the leg when the upper ends of the two parts are forced apart and fixed in the corresponding recesses in the seat. Pg. 3 Description of the Invention Each leg is preferably made from two straight approx vertical components, jointed together at the base, fixed with a bolt approx one third the way up, and pulled apart in two dimensions at the top, jointed into housings and fixed. When forced apart each component mutually pre-stresses the other, employing wood’s natural elasticity to create stiffness, integrity and stability from much smaller stock then possible in typical furniture. This leg maintains its strength by not being steam bent or kerf bent, or heated in anyway except the usual kiln drying at the sawmill. As opposed to laminated bends, this method relies on and harnesses the stresses and elasticity rather than constrains them. Construction of a chair embodying the invention will now be described. In particular, measurements are given for the purpose of illustration only. Cut square section scantlings (16x16mm for chairs - thicker for table legs) out of straight stock (rift sawn Elm or Ash best). Two components make one leg. Crosscut to length (approx 435mm front leg components / 650mm back leg forward component / 950cm for back leg rear component which forms part of chair back. Joint (domino or otherwise) the two leg components together at the base to resist forces when pulled apart at the top later. Approx a third of the way up drill through both components and fasten together with a nut and bolt. A metal fixing like this is necessary to resist the stresses as the two leg components are pulled apart at the top. Machine up your seat at approx 34mm thickness. This is necessary to provide enough material support for the legs to be housed into. Cut square notches into the thickness, perpendicular to the top of seat and parallel with seat edge bevel. Each leg is situated at the corner and requires two notches for housing the two leg components per leg. At least one notch must be angled to accommodate the curve / deflection as the two components are pulled apart and housed at the top. The back legs are manufactured and act the same as the front but also proceed past the housings to form the back. They are also pulled together by the top rail. The square section allows the two leg components to be orientated in a precise and fixed way. This means we can house one leg component and then pull the other forward AND to the side to be housed and fixed. This is now stressing the components in two dimensions. Each component is fixed with a screw / bolt / or dowel into the seat / bench / table top etc. The top rail and seat is cut to house the back rest. The back rest (approx 6mm x 106mm x 555mm) is housed into the seat. The two longer (950m) leg components are pulled together at the top (pre-stressing them) the top rail screwed into them. Pg. 4 This rail houses the top of the back rest and as it is screwed into the long back leg components it pre-stresses the back rest as well as the long leg components which form part of the back. The last component is the bow which joins the seat to the components of the back legs. This is made of approx 5.5mm x 21 mm x 1650mm It is either steamed at the middle of the length or soaked in cold water overnight to allow the sharp bend. Once steamed briefly, one end is screwed into the LHS seat edge. It is then pulled over the LHS back leg forward component, then back rail, then the RHS back leg forward component, and finally, pulled taught, it is screwed into the RHS seat edge. Then where this bow meets the LHS and RHS back leg forward components it is screwed into them, and where it meets the chamfered edges of the LHS and RHS back top rail it is screwed into it as well. The front lower edge of the seat is preferably bevelled. The seat is preferably dished to make it comfortable to sit on. The bottom edges of the legs are preferably bevelled with a spokeshave for aesthetics. The finished chair preferably receives two coats of oil.

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