Furniture subframe

Abstract

The invention is a structural foam furniture subframe which replaces the customary assembly of wooden pieces with a unitary, load bearing, injection molded, plastic space frame of angularly jointed plate sections, said subframe including at least one peripheral load bearing recepticle having at least four plate sections that are each connected at one end thereof to and radiating outwardly from the periphery of said receptical, said subframe having attachment surfaces on all sides thereof and having novel fastener attachment sections to accommodate conventional wood type fasteners.

Description

BACKGROUND OF THE INVENTION

Furniture subframes, such as for upholstered chairs and sofas, have been commonly fabricated from a number of separate pieces of wood which are individually shaped by machine and then glued, screwed, or the like, together during which time the assembled pieces are held in a fixed relationship with the aid of jigs or clamps. It is obvious that this method of fabrication involves a great deal of labor and does not lend itself to mass production techniques. Further problems are the greatly increased cost of lumber, the slowness of curing of lumber, the poor quality of cuttings of lumber, the excessive waste in forming other than straight shapes and dimensional instability of cut lumber. The generally limited supply of fine hardwood pieces has resulted in poor quality furniture chassis. As a consequence of the lack of good natural material, poor quality material has been substituted. Poor mass production type of joints and joining techniques produce furniture that is undesirably weak and subject to premature structural failures. The instant invention provides a low-cost solution to the rising costs and shrinking availability of wood for upholstery frames. The one-piece, injection molded furniture subframe is lightweight providing ease in handling and reduced cost of shipment as well as providing a frame that will not shrink, swell or dry out with the changes in humidity.

SUMMARY OF THE INVENTION

It is the purpose of the instant invention to provide a unitary furniture subframe to replace customary assemblies of wooden pieces. To accomplish this purpose, the instant invention consists of an injection molded one piece plastic member having upholstery attachment surfaces and novel structural arrangements to provide an integral load bearing structure.

OBJECTS OF THE INVENTION

It is a primary object of the instant invention to provide a furniture subframe that will replace the customary assembly of wooden pieces.

Another object of the instant invention is to provide a frame structure that will allow economical assembly line production of furniture.

Yet another object of the instant invention is to provide a lightweight furniture frame that is not affected by changes in temperature and humidity.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of one embodiment of furniture subframe of the instant invention.

FIG. 2 is a perspective view of another embodiment of furniture subframe of the instant invention.

FIG. 3 is a perspective view of yet another alternate furniture subframe of the instant invention.

DESCRIPTION

With continued reference to the drawing, FIG. 1 shows two furniture subframes generally at 10 and 20 which may be connected together by wooden cross members 12, 14 and 16 shown in phantom line to form a sofa bed frame. The subframe 10 and 20 are raised from the floor by legs 18 also shown in phantom. Legs, castors or the like are connected to the subframes by well-known wood furniture techniques and hardware. The subframes contain a plurality of spaced essentially parallel ribs or walls 19 which approximate adequate spans and provide bearing surfaces for wood type fasteners. These spaced essentially parallel ribs or walls are an important part of the invention. Subframes 10 and 20 are one-piece, injection molded plastic members made from simple two-piece molds. These frames may be made from polypropylene structural foam or other injection moldable materials, such as polystyrene or high density polyethylene. Polypropylene structural foam such as that made from "Pro-fax" polypropylene resin is preferred since it provides a low cost finished piece having a high density surface and a low density interior that is ideal for stapling, nailing or screwing. These subframes are injection moldable from simple two-piece molds. In addition to the novel use of polypropylene structural foam, the subframes 10 and 20 incorporate space frame technology in their structural design to provide integral load-bearing structures. The subframes of the instnat invention are not the mere duplication of wooden frames in plastic nor are they non-supportative trim pieces.

As can be seen in FIG. 1, subframes 10 and 20 provide peripheral load-bearing recepticles such as five-sided load bearing boxes 22a, 22b and 22c that are integral with the subframes into which the cross members are inserted and contained by nailing or other means. The five-sided box provides bearing strength and also a convenient positive stop for easy registration in assembly. It is also within the scope of the invention to use deep four-sided boxes with or without stop means. A key feature of the instant invention is the connection of the peripheral load-bearing recepticle to the other portions of the subframes. This connection works in essence much like the connection for a cantilever beam and therefore must sustain great stresses. To overcome this stress problem the instant invention in every embodiment utilizes at least one peripheral load-bearing recepticle that is interconnected with other portions of the subframe by at least four plate sections that are each connected at one end thereof to and radiate outwardly from said periphery. In FIG. 1 this recepticle is typically illustrated by box 22b having at least four plate sections, such as 23a, 23b, 23c, 23d, 23e, and 23f, each connected at one end therefo to and extending radially outwardly from the periphery of box 22b said periphery defined by the four sides of box 22b. The fifth side which closes a five-sided box for registration purposes is not considered to be connected at one end thereof to and as radiating outwardly from the periphery defined by the other four sides.

FIG. 2 shows an alternative embodiment of the instant invention. Furniture subframes shown generally at 30 and 40 will provide load-bearing structures for a recliner chair. As can be clearly seen in subframe 30, peripheral load-bearing recepticles 32a and 32b are provided for wooden cross members 31 and 33 shown in phantom. Peripheral load-bearing recepticle 32a is interconnected to the other portions of the subframe by at least four radially extending plate portions 34a, 34b, 34c and 34d. Integral flange 36 provides an adequate support and fastening area for the recliner mechanism (not shown). The unique plastic subframes also provide reinforced areas 38 and 42 for the attachment of castors shown in phantom. Subframes 30 and 40 likewise utilize space-frame technology such as Z sections, gusseted U-channels and double Z sections to achieve optimum strength and low weight. As can be seen in both FIGS. 1 and 2, the subframes also provide continuous tacking surfaces such as 28 in FIG. 1 and 44 in FIG. 2 on all sides thereof. FIG. 1 also provides a large pull through opening 29 for purposes of upholstering. Subframes 30 and 40 of FIG. 2 allow any configuration of soft or hard foam cushion to be attached to the subframe upon surface 46.

FIG. 3 shows another alternative embodiment of the instant invention. Side subframes shown generally at 50 and 60 cooperate with back section shown generally at 70 to form the load-bearing structure for a rocker. Side subframes 50 and 60 provide peripheral load-bearing recepticles 52a, 52b and 52c for connecting members shown in phantom. Peripheral load-bearing recepticle 52b is interconnected with other portions of the subframe by at least four radially extending plate portions 54a, 54b, 54c and 54d. Back section 70 is connected to side subframes 50 and 60 by a spring rod and attaching plate 58. By use of the space from technology discussed earlier, the side subframes and back section provide a high strength, lightweight, load-bearing structure. The side subframes 50 and 60 also provide attaching areas 62 and 64 for various arm configurations. Wide openings 66 are provided for upholstering purposes. Continuous tacking surfaces shown typically at 68 are also provided on all sides. Back section 70 provides bridging for unsupported upholstery material, for example, cotton padding which can be added during upholstering.

Thus, it can be seen that the injection molded structural foam or the like material provides load-bearing structures that are lightweight, utilizing space-frame technology and structures which eliminate inherent deficiencies and weaknesses associated with the construction of wood pieces.

It is understood that the invention is not limited to the precise description given, but that changes are contemplated which readily fall within the spirit of the invention as shall be determined by the scope of the appended claims.

Claims

What we claim and desire to protect by Letters Patent is:

1. A furniture subframe comprising:

a pair of symmetrical load bearing, unitary, plastic subframes, each of said subframes being comprised of a plurality of joined plate sections, said subframes being disposed in essentially parallel, mirror image like spaced apart relationship to each other, each of said subframes including at least one load bearing recepticle integral with said subframe, said recepticles each having at least four plate sections each connected at one end thereof to and radiating outwardly from the sides of said recepticles to brace said recepticles and interconnect said recepticles with said subframes; and

an interconnecting member having opposite ends thereof contained within said recepticles to connect said subframes.

2. Subframes as in claim 1 wherein said further included leg attachment areas, said areas being a plurality of spaced essentially parallel plates which approximates spans and provide bearing surfaces for wood type fasteners.

3. Subframes as in claim 2 wherein said subframes further includes upholstery tacking surfaces on all sides thereof.

4. Subframes as in claim 3 wherein said plastic material is polypropylene structural foam.