Steelcase Inc.

John L Hendricks

Robert J Battey

Brian H Root

Kurt R Heidmann

Robert M Scheper

Robert S Grooters

Bruce G Rose

Michael A Kolarik

Nancy A Funk

Charles L Cartwright

A chair base includes a tapered tubular center hub defining a longitudinal centerline and a plurality of radially extending tubular legs. Each leg has top, bottom, and opposing sidewalls defining a rectangular cross section that decreases as the leg extends from the hub. The top and bottom walls each have an arcuately shaped end that is welded to the center hub by top and bottom ring welds. The sidewalls of each leg have enlarged wall sections that are flat and parallel and further have bent flanges adjacent the hub that are angled inwardly from the enlarged wall sections toward the longitudinal centerline. The bent flanges are oriented approximately radially from the centerline to provide optimal structure and to provide clearance between adjacent legs. The clearance prevents interference between adjacent legs despite dimensional variation in the legs from manufacturing and tolerance considerations, thus facilitating assembly. The hub is formed from a constant-thickness wall to define a tapered one-piece tubular shape, with the constant-thickness wall having an inner surface defining a larger upper diameter and a smaller lower diameter for mateably receiving and stably supporting a tapered chair-supporting post.

Chair base

An assembly for mounting the piston rod of a gas spring, such as may be used in adjustable-length chairs, stools, tables or the like, is disclosed. The hub tube used in the assembly is flared outwardly at its lower end to form a shoulder. The washer, to which the end of the piston rod is attached, is supported on the shoulder against movement into the tube. After the washer is placed against the shoulder, the end of the tube is rolled inwardly to contain the washer in the downward direction. The expanded area for support of the washer increases resistance to upward movement of the washer in response to the strong forces exerted by the gas spring. The expanded lower section of the tube also provides an area onto which the legs of the chair may be welded.

Hub tube/washer assembly

A chair base includes a leg assembly having a plurality of radially extending legs, and a leg cover adapted to cover the legs. The tubular legs have a top surface divided by a centerline and have apertures offset from the centerline. The leg covers are adapted to cover the legs, and the leg covers include downwardly extending off-centered bosses for engaging the apertures. Each of the tubular legs has an end with aligned vertical holes therein. A sleeve-like pintle receiver is located in the aligned vertical holes and flared at its top and bottom to hold the pintle receiver in the tubular legs. The leg assembly includes a tubular center hub. The plurality of radially extending tubular legs each have a top wall, a bottom wall, and opposing sidewalls, the top and bottom walls each having an arcuately shaped end engaging the center hub. A pair of ring welds extends continuously circumferentially around the center hub for welding the arcuately shaped ends of the top and bottom walls to the center hub. In a modified form, the covers include a plurality of flat-topped intermediate retainers shaped for attachment to a top of the legs, and a plurality of aesthetic flat-bottomed trim pieces shaped for mating adhering attachment to the top of the retainers.

A chair base includes a leg assembly having a plurality of radially-extending legs, and a leg cover adapted to cover the legs. The tubular legs have a top surface divided by a center line and have apertures offset from the center line. The leg covers are adapted to cover the legs, and the leg covers including downwardly extending off-centered bosses for engaging the apertures. Each of the tubular legs have an end with aligned vertical holes therein. A sleeve-like pintle retainer is located in the aligned vertical holes and flared at its top and bottom to hold the pintle retainer in the tubular legs. The leg assembly includes a tubular center hub. The plurality of radially extending tubular legs each have a top wall, a bottom wall and opposing side walls, the top and bottom walls each having an arcuately shaped end engaging the center hub. A pair of ring welds extend continuously circumferentially around the center hub for welding the arcuately shaped ends of the top and bottom walls to the center hub. In a modified form the covers include a plurality of flat-topped intermediate retainers shaped for attachment to a top of the legs, and a plurality of aesthetic flat-bottomed trim pieces shaped for mating adhering attachment to the top of the retainers.

A method and apparatus for forming a length of tubing into a curved, unbalanced and non-uniform shape continuously bends the tubing and then changes the cross-sectional shape along the length of the tubing to eliminate springback and provide a stable part with shape retention. The apparatus includes relatively movable upper and lower half die shoes. A form post, a forming steel subassembly, a plurality of slides and driver posts are positioned on the shoes in Juxtaposed relationship. A clamp holds a length of tubing against the form post. Movement of the die shoes towards each other shifts the slides to continuously bend the tube about the form post. After the bending operation, the cross-sectional shape of the tubing is changed from a generally circular shape towards an oval or generally rectangular shape. A pressure is applied to induce stresses which eliminate springback and provide a stable part.

Apparatus for forming tubing into curved, unbalanced and non-uniform

A method and apparatus for forming a length of tubing into a curved, unbalanced and non-uniform shape continuously bends the tubing and then changes the cross-sectional shape along the length of the tubing to eliminate springback and provide a stable part with shape retention The apparatus includes relatively movable upper and lower half die shoes A form post, a forming steel subassembly, a plurality of slides and driver posts are positioned on the shoes in juxtaposed relationship. A clamp holds a length of tubing against the form post. Movement of the die shoes towards each other shifts the slides to continuously bend the tube about the form post. After the bending operation, the cross-sectional shape of the tubing is changed from a generally circular shape towards an oval or generally rectangular shape. A pressure is applied to induce stresses which eliminate springback and provide a stable part.

Growing community of inventors

Grand Rapids, MI, United States of America

John L Hendricks