Molded Furniture Leg

Field of the Invention

This invention relates to an improvement in the construction of a furniture leg which is adapted to be secured in place at the underside of various types of furniture such as upholstered chairs, sofas, cabinets, bedding frames and the like.

The improved leg structure, which is produced by conventional injection molding technique using a thermosetting synthetic plastic such as a high impact polystyrene or acyrilonitrile butidene styrene is essentially a hollow body featuring a central, longitudinally extending core and a plurality of laterally extending ribs which terminate in the outer wall of the leg which may have any desired profile such as frusto-conical, cylindrical or polygonal, e.g. hexagonal or square. The central core, which preferably is also hollow, in conjunction with the overall hollow character of the leg provides a reinforced structure which is exceptionally strong in relation to its mass and requires only a minimal amount of material for its manufacture and is therefore also most economical to produce.

Assuming the central core to be hollow, the internal diameter of the core at its upper end is sized to provide a driving fit for anchoring a stud by which the leg is fastened to the furniture, and the internal diameter at its lower end is sized to provide a driving fit through the closed bottom wall for the nail shank of a bottom furniture glide. The internal diameter of the core progressively decreases from the top down resulting in a corresponding increase in thickness of the core wall and the reinforcing ribs also progressively increase in thickness from the top down.

A preferred construction for a furniture leg in accordance with the invention is illustrated in the accompanying drawings wherein:

FIG. 1 is an exploded view of the three component parts of the furniture leg, these being the molded body, the attachment stud at the upper end and the glide at the lower end;

FIG. 2 is a top plan view of the leg;

FIG. 3 is a vertical sectional view of one of the reinforcing ribs taken on line 3--3 of FIG. 2; and

FIG. 4 is a vertical diametral section of the leg taken on line 4--4 of FIG. 2.

With reference now to the drawings, the furniture leg constructed in accordance with the invention has an inverted tapered configuration, i.e. a frusto-conical outer wall 1 and is produced by conventional injection molding technique using a thermosetting plastic such as a high impact polystyrene, or acyrilonitride butidene styrene. The leg includes a longitudinally extending central hollow cylindrical core 2 provided with equally spaced radially extending ribs 3 which terminate in the outer wall 1. In the illustrated embodiment, four such ribs are provided and are spaced 90.degree. apart relative to the longitudinal axis of the leg.

Since in view of the frusto-conical configuration of the leg, the reinforcing ribs 3 decrease in width from top to bottom they preferably progressively increase in thickness from top to bottom as depicted in FIG. 3.

The internal diameter of the cylindrical core 2 is not uniform throughout its length but rather progressively decreases in diameter from top to bottom thereby also resulting in a corresponding progressive increase in thickness of the core wall. The internal diameter of the core 2 at its upper end portion 2a, is sized to provide an undersized, driving fit for the lower section 4a of a stud 4 by which the leg is to be attached to the furniture. This lower section 4a can be suitably profiled such as by the illustrated longitudinally extending knurling so as to anchor it securely in place within the plastic material. The upper section of stud 4 is threaded at 4b for fastening into a furniture bracket in any conventional manner. The stud 4 can be driven into the hollow portion 2a of core 2 by means of a so-called "sonic" welder. Using this method, the molded plastic under pressure is heated, flowing around the knurled part of the stud 4 thus making a permanent bond that prevents the stud from pulling out, or turning within the core.

The furniture leg in accordance with the invention may be used with various types of conventional leg fastener structures suitable for receiving the upper portion of stud 4. Various types are disclosed for example in U.S. Pat. Nos. 1,512,653; 1,928,469; 3,135,309; 3,207,022 and 3,263,630.

At the bottom of the leg the portion 2b of the hollow core has a much smaller diameter which is sized to provide an undersized, driving fit through the closed bottom wall 5 for the nail shank of a bottom furniture glide if such a glide is desired. Two alternative glide structures are depicted in FIG. 1, namely a plain button type of glide with its head 6 and nail shank 6a, and a more ornamental one with its head 7 and nail shank 7a. The heads of the glides can be either metal or a plastic such as nylon.