Chairs and seats – Bottom or back – Cushioned
Reexamination Certificate
1999-02-18
2001-01-09
Barfield, Anthony D. (Department: 3624)
Chairs and seats
Bottom or back
Cushioned
C297S452520, C005S259100, C267S087000
Reexamination Certificate
active
06170915
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a seat assembly. More particularly, this invention relates to a wire construction for a sprung seat assembly.
BACKGROUND OF THE INVENTION
Prior to the use of springs, seat cushions were simply stuffed with matting, fill or other soft fibers. After a period of use, the cushion stuffing would settle, often resulting in a hard, lumpy, uncomfortable cushion.
The advent of the coil spring solved many of the prior problems. The early coil springs were placed in a frame under the seat cushion padding in a sufficient number of rows to provide proper seating support. The coil springs advantageously provided a consistent spring resilience throughout the seating area. However, this manner of providing cushion seating was expensive due to the large number of coil springs needed to support a cushion in a consistent manner.
The development of the sinuous spring caused many manufacturers to adopt this spring as an economical substitute for the prohibitively priced coil spring structure. The sinuous springs have a zig-zag pattern and are generally disposed in an upwardly bending arc between two parallel sides of a frame. Rows of sinuous wire springs are generally attached in a parallel alignment between the front and rear walls of cushion seating frames, offering both comfort and resilience. While the substitution of sinuous springs for coil springs reduced the amount of wire and the cost of the springs by between 60 and 80%, the firmness and comfort offered by only the rows of sinuous wires did not meet the needs of all. Heavier people found that the sinuous wire springs designed for people of average weight do not provide the desired resilience and have a tendency to bottom out. “Bottoming out” as used in this application, is a term of art generally referring to that condition in which the force which has been applied to the springs in a cushion exceeds the ability of the springs to resiliently resist the applied force, thus causing the springs to sag to a position in which further travel of the springs is restrained by supporting structure or by the fully extended springs. The use of stronger, stiffer springs, while providing more comfort to heavier persons, proved to be too hard and uncomfortable for lighter persons. The problem of providing proper support and resilience in cushion seating for heavier persons has also been compounded by the fact that the average person of today is bigger and heavier than the average person of 40 years ago. In addition, today's consumer is more sophisticated and demanding than in the past. Thus, the requirements for seat cushion constructions which can provide acceptable levels of support and comfort to a broader spectrum of people are more demanding today than in the past.
Attempts to overcome the aforementioned problems and to provide cushion seating with comfort and resilience have included the combination of sinuous springs and coil springs. The coil springs were often placed between a flexible base support and the sinuous springs to provide more resilience to the sinuous spring. For example, U.S. Pat. No. 2,234,253 discloses a spring cushion construction which includes a plurality of parallel-disposed sinuous springs with coil springs disposed beneath them. The lower ends of the coil springs are supported by another row of sinuous springs extending transversely to the top row. U.S. Pat. No. 2,280,912 discloses a spring arrangement for bedsprings, boxsprings, etc., having a plurality of parallel sinuous springs form the top surface of the cushion spring assembly. The sinuous springs are secured to tapered coil springs which are in turn secured to a lower level of sinuous springs transversely positioned with respect to the top sinuous springs. U.S. Pat. No. 4,597,566 discloses another form of spring cushion seating in which coil springs are placed between a plane of nonresilient wires, supported on the frame by helical edge springs, and a base bar. However, this patent does not provide the feel traditionally associated with the use of sinuous springs.
Furthermore, traditional spring cushion seating is generally heavy due to the amount and composition of the structure used to provide support to the sinuous and coil springs. While the cushion spring structures of the prior art solved some of the problems inherent with sinuous wire-only spring structures by reducing the tendency to bottom out, the prior art structure still lacks the requisite combination of firmness and deep resilience which is desirable in cushion seating today and that, in manufacture, results in a relatively lightweight finished product.
OBJECTIVES OF THE INVENTION
It is therefore an objective of the invention to provide a seat assembly having a reduced overall weight.
It is another objective of the present invention to provide a seat assembly having deep resilient support secured to a lightweight support structure.
It is a further objective of the present invention to provide a lightweight seat assembly that allows a user to variably select the position of the sprung elements therein to provide varying degrees of resilient support.
SUMMARY OF THE INVENTION
These objectives are achieved by creating a seat assembly having a frame with front and rear rails to which a spring structure is secured. The spring structure has a plurality of parallel and upwardly bowed sinuous springs traversing the frame from the front rail to the back rail, the sinuous springs being secured to the top edges of respective front and back rails. The sinuous springs are connected by plural upper stabilizer wires laid transversely across and secured to the sinuous springs. A plurality of coil springs are also secured at their upper turns to the upper stabilizer wires.
The coil springs have lower turns secured to relatively lightweight downwardly bent support wires that are attached at either end to the top edges of the front and rear rails. Preferably, the support wires have upwardly bent portions against which the lower coil turns of the coil springs are secured. The lower turns of the coil springs are secured to each other by lower stabilizer wires running transversely to the support wires.
Relatively short tie wires are threaded over the top of the coil spring bottom turn and under the bent portion of the support wire. Either end of the tie wire is secured to the lower stabilizer wires so as to maintain the coil spring, lower stabilizer wire, and support wire in secure engagement.
The sinuous springs and coil springs provide resilient support to a user seated upon the assembly. The support wires secured to the bottom turns of the coil springs provide relatively lightweight rigid support to the sinuous and coil springs by using the transversely laid lower stabilizer wires and tie wires to maintain the coil springs secured relative to each other within the seat assembly.
The features and objectives of the present inventive seat assembly will become readily apparent from the detailed description taken in conjunction with the accompanying drawings.
REFERENCES:
patent: D. 348162 (1994-06-01), Issacs
patent: 441653 (1890-12-01), Foster
patent: 673509 (1901-05-01), Staples
patent: 752783 (1904-02-01), Kilmer
patent: 793172 (1905-06-01), Bigelow
patent: 1036904 (1912-08-01), Raftery
patent: 1164534 (1915-12-01), Lewis
patent: 2158647 (1939-05-01), Wolfe
patent: 2186548 (1940-01-01), Lotz
patent: 2305530 (1942-12-01), Hopkes
patent: 2395402 (1946-02-01), Fisher
patent: 2675065 (1954-04-01), Keller
patent: 3715766 (1973-02-01), Slominski
patent: 4819920 (1989-04-01), Barber
patent: 4886250 (1989-12-01), Lucas
patent: 5188343 (1993-02-01), Galea
patent: 5615869 (1997-04-01), Phillips et al.
Barfield Anthony D.
L&P Property Management Company
Wood Herron & Evans LLP
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