Welded base for chair or the like

[57] ABSTRACT

In a metal chair base of the type comprising an upright cylindrical hub and a plurality of legs radiating from the hub, each of the legs is a channel member containing a short channel section inserted within and welded to the leg, and also abutting and welded to the hub. The legs and hub may be chrome plated or otherwise finished before assembly of the legs to the hub, as welding of the channel sections to the hub does not cause visible weld marks or heat tarnishing of the plated hub and leg surfaces.

Claims, 8 Drawing Figures

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PATENTED AUG 81972

3,682,425

SHEET 1 OF 2

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BY

INVENTORS DAV/D H. VINCENT RODNEY Z, JOHNSON

ATTORNEY

PATENTED»^ era??

3.682.425

SHEET 2 OF 2

40

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3,682,425

WELDED BASE FOR CHAIR OR THE LIKE

BACKGROUND OF THE INVENTION

This invention relates to metal furniture components and in particular to metal furniture bases such as bases for chairs or the like. In a more specific sense the invention is directed to welded chair base assemblies.

In one common type of chair base assembly, a plurality of tapered legs are disposed radially around an upright cylindrical hub (to which the chair seat or other furniture article may be connected) and secured to the hub as by welding. It is also common practice to provide an attractive surface finish for such an assembly, for example by chrome plating the assembly.

Heretofore in the manufacture of chrome-plated or otherwise finished chair base assemblies of the described type, it has ordinarily been necessary to assemble and weld the legs and hub prior to finishing, in order to avoid visible weld marks on the finished article and also to avoid the discoloration of the finished surface that might be produced by the heat of the welding operation if performed subsequent to finishing. Among the disadvantages of this conventional practice, there may be particularly remarked the difficulty in plating or otherwise finishing the bulky and cumbersome assembled article.

Various types of concealed weld joints have been proposed for metal furniture assemblies. For example, U. S. Pat. No. 3,531,147 discloses an effective concealed weld arrangement for securing a channel member in end-butting relation to a flat surface of a frame member. However, the provision of a weld joint between leg and hub in a chair base of the described type presents problems not encountered in other types of furniture frame joints, owing both to the curved configuration of the hub surface and to the special stresses to which the joint is subjected.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a metal furniture assembly, suitable for use as a chair base or the like, including elements secured to each other by a concealed weld joint. A further object is to provide a new and improved welded chair base assembly, of the type comprising a cylindrical hub and radial legs, wherein the legs and hub are weldedly joined in a manner that permits chrome plating or other finishing of the legs and hub before assembly and welding without likelihood of damage to the finished surface by heat tarnishing from the weld, these joints being nevertheless strong enough to withstand the stresses imposed on such chair bases.

To these and other ends, the present invention contemplates, in a prefinished metal furniture base including a first member having a cylindrical surface and a second member extending radially outwardly from the cylindrical surface with one end abutting that surface, a new and improved arrangement for securing the members together by welding. More particularly, in accordance with the invention, the second member is a channel member having sides with longitudinal edges bent inwardly to form facing return flanges. A channel section is received within the channel of the second member adjacent the end abutting the first member; the channel of this section opens in the same direction as the channel of the second member, and the section has sides respectively welded to the return flanges of the second member. The webs of the second member and the channel section diverge from each other toward the end of the second member abutting the first member, so that the aforementioned webs are spaced apart at that end of the second member. Further, the end of the channel section facing the first member is offset with respect to the adjacent end of the second member to conform to the curvature of the cylindrical surface of the first member so that the ends of both the channel section and the second member engaged the cylindrical surface. The channel section is welded to the first member along the junction of the internal edge of the last-mentioned end of the channel section and the cylindrical surface.

In this construction, the first and second members may be separately finished (e.g. chrome plated) before they are assembled and welded. That is to say, after the channel section is inserted within the second member and welded to the return flanges of the second member, but before the channel section is welded to the first member, both members may be subjected to plating or other finishing operations. Subsequent welding of the two members occurs only along the internal junction between the channel section and the first member surface. Since the web of the channel section is spaced away from the web of the second member at the locality of abutment with the first member, and further, since the sides of the channel section are welded to the return flanges of the second member, the heat of welding is not transmitted to the external surface of the second member sufficiently to cause tarnishing or other damage to the finished surface appearance. At the same time, the defined arrangement provides a very strong and secure welded joint between the two members, fully adequate (for example) for a chair base wherein the first member is the upright cylindrical hub of the base and there are a plurality of second members (i.e. legs) extending radially outwardly from the hub.

Further features and advantages of the invention will be apparent from the detailed description hereinbelow set forth, together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a chair having a base embodying the present invention in a particular form;

FIG. 2 is a fragmentary plan view of the base of FIG. 1;

FIG. 3 is a fragmentary elevational view of the base ofFIG. 1;

HG. 4 is an enlarged plan view, partially broken away, of one leg of the base of HG. 1;

HG. 5 is a sectional view taken along the line 5—5 of FIG. 4;

HG. 6 is a sectional view taken along the line 6—6 of HG. 5;

HG. 7 is a view taken along the line 7—7 of FIG. 5; and

HG. 8 is a sectional view taken along the line 8—8 of FIG. 5.

DETAILED DESCRIPTION

Referring to the drawings, the invention is illustrated as embodied in a metal (e.g. steel) base 10 for a chair having a seat 11 mounted on the base as shown in FIG.

3,682 3

1. The base 10 comprises an axially vertical cylindrical hub member 12 and four leg members 14 extending radially outwardly from the hub member 12 at right angles to each other. The seat 11 is secured to a vertical post 16 which extends downwardly from the seat and is 5 mounted in conventional manner in the hub 12. Four casters 18 are respectively mounted at the outer ends of the four leg members 14.

Each leg member 14 is a downwardly opening steel channel member which extends generally horizontally ¹⁰from the hub 12 but with a slight downward slope. The channel member forming each leg member 14 is tapered, attaining its maximum depth at the point at which the inner end of the leg member 14 abuts the hub 12. Thus the web portion 20 of the leg member 14 slopes downwardly away from the hub 12, while the sides 21 of the member 14 decrease progressively in width in the direction away from the hub. The web 20 and the sides 21 are essentially planar in the illustrated 20 embodiment of the invention, the sides 21 lying in vertical planes.

In each member 14, the longitudinal free edge 21a of each channel side 21 is bent inwardly and upwardly to form an inwardly facing longitudinal return flange 22, 25 there being two such flanges 22 extending in parallel facing relation along the interior of the channel of each member 14. The outer end 24 of each member 14 is closed by generally conventional forming and welding operations. The inner end 25 of each member 14 is 30 open, and abuts the cylindrical surface of the hub 12 in conforming relation thereto, the leg member sides 21 engaging the hub surface along vertical lines and the web 20 having a concave arcuate inner edge shaped to closely engage the hub surface. ³⁵

A downwardly opening, axially vertical pintle socket 26 is mounted in the channel at the outer end of each member 14, and welded to the member 14, for receiving and holding the post of a caster 18. A steel reinforc- _ ing strip 28 may be mounted between the two return flanges 22, extending from the pintle socket 26 for some distance toward the hub but leaving open at least the portion of the channel of member 14 at and adjacent the inner end 25. The reinforcing strip 28 (best 45 seen in FIGS. 5,7 and 8) is secured to the return flange 22 by welds 30.

In accordance with the invention, within the inner end (the end adjacent hub 12) of each leg member 14, there is disposed a short channel section 32, e.g., 50 fabricated of steel, opening in the same direction (i.e. downwardly) as the leg member. Each channel section 32 is so dimensioned as to be received within the channel of its associated member 14, in the position best seen in FIGS. 4-6. The lower edges 33 of the sides of 55 the channel section 32 rest on the edges 21a of the return flanges 22 of the leg member 14 and are secured thereto by welds 34.

The outer edge 35 of the web portion 36 of the channel section 32 abuts the under surface of the web 20 of ⁶⁰leg member 14 and may be welded thereto as indicated at 37. However, inwardly of edge 35 (i.e., in the direction toward the hub 12), the web 36 diverges from the web 20 of the outer leg member so that, as best seen in FIG. 5, the webs 20 and 36 are increasingly spaced ⁰apart as they approach the hub 12. It may be noted that both webs 20 and 36 may be substantially planar; in the ,425 embodiment illustrated, web 36 is shown as lying in an essentially horizontal plane, while web 20 lies in a sloping plane that intersects the plane of web 36 along the line of edge 35.

The disposition of the channel section 32 is such that its inner end 39 abuts the surface of hub 12 when the inner end 25 of the associated leg member 14 also abuts the hub surface. Thus the inner end of the channel section 32 is offset outwardly (i.e., away from the center of the hub) with respect to the inner end 25 of the leg member so as to conform to the curvature of the hub. The inner margin 40 of the channel section web 36 is cut away to accommodate the hub curvature. As will be apparent, the vertical inner edges of the sides of channel section 32 continuously engage the cylindrical hub surface along lines parallel to the hub axis.

As further shown in FIGS. 4-6, the channel section 32 is welded to the hub 12 by a weld 42 extending along the junction of the internal edges of the sides of the channel section and the cylindrical hub surface. The weld 42 may be a continuous weld extending also along the junction of the internal edge of the web 36 and the hub surface. Thus, each leg member 14 is secured to the hub 12 by means of the channel section 32 contained within the inner end of the leg member and welded both to the leg member and to the hub, these welds being entirely concealed by the leg member.

In the manufacture of the described structure, the pintle sockets, reinforcing strips and channel sections are first mounted in and welded to the leg members 14, i.e., prior to assembly of the leg members to the hub. Thereafter - also prior to such assembly - the leg members and hub may be chrome plated and/or subjected to other surface-finishing operations. Each leg may then be positioned at its desired location in abutting relation to the hub, and secured thereto by formation of the weld 42, i.e., by welding the channel section 32 to the hub. Owing to the fact that the web 36 of the channel section is spaced away from the web 20 of the leg member at the locality of junction with the hub, and owing also to the fact that the channel section 32 is welded to return flanges 22 of the leg member rather than directly to the outer walls of the leg member, the welding of channel section 32 to the hub 12 along the line indicated at 42 does not cause such heating of the outer surface of the leg member 14 as to tarnish or otherwise impair a previously applied chrome plate or other surface finish. Also, the locality of the internal weld 42 is sufficiently remote from exposed portions of the hub surface 12 to prevent any tarnishing or other impairment of the prefinished hub surface at localities visible to the eye. The weld 42 is entirely concealed, and the channel section 32 is hidden from view, by the leg member 14 which extends around it into abutting relation with the hub 12. Nevertheless, the weld 42 is easy to form, since the locality of that weld is readily accessible from below through the opening of the channel of member 14, and the weld provides a joint fully adequate in strength for normal service in use of the assembled base as a chair base or the like.

All the welds in the described structure may conveniently be formed by so-called metal inert gas welding, which (as will be appreciated by those skilled in the art) is a resistance welding procedure in which the weld metal is fed as a wire to the welding locality while sur3,682,425 rounded by an inert gas such as carbon dioxide to contain the heat in the welding area, with a positive charge on the wire and a negative charge on the object to be welded.

It is to be understood that the invention is not limited to the features and embodiments hereinabove specifically set forth but may be carried out in other ways without departure from its spirit.