Seat Assembly Having Sinuous Springs

Abstract

A seat assembly for insertion into a piece of furniture has a frame having opposed sides. Each side may have openings therein for supporting clips. Upper and lower sinuous wires extend generally across the frame. Upper stabilizer wires are secured to the upper sinuous wires and maintain the spacing thereof. The clips secure each of the sinuous wires to the frame. Coil springs are secured to the upper stabilizer wires and the lower sinuous wires. The clips securing the upper and lower sinuous wires alternate along the sides of the frame.

Description

FIELD OF THE INVENTION

The present invention relates to a seat assembly for use in furniture.

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 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 zigzag 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 percent, the firmness and comfort offered by only the rows of sinuous wires did not meet all of the needs of manufacturers. 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 document, 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. 6,170,915, which is fully incorporated by reference herein, discloses a seat assembly incorporating both coil springs and sinuous springs. The coil springs of such a spring assembly extended between upper sinuous springs and lower support wires.

Later, a seat cushion incorporating both coil springs and sinuous springs was developed which replaced lower support wires with lower sinuous wires to support the coil springs. Such a seat cushion is shown in FIGS. 1 and 2 of this document. As described below, the weak point in such a seat cushion is the location of the clips securing the coil springs to the lower sinuous wires since the load is ultimately borne by the bottom layer. Another drawback to the prior art seat cushion shown in FIGS. 1 and 2 is that twice as many lower sinuous wires and additional clips must be used compared to the seat assembly of the present invention. The prior art seat assembly components are more difficult to assemble than the components of the present invention. The present invention improves the durability and performance of the seat assembly by replacing the two short pieces of bottom sinuous wires with one longer piece of sinuous wire, which spans from one side of the frame to an opposed side of the frame. The coil springs rest on top of the longer continuous sinuous wires, as opposed to being suspended between two shorter pieces of sinuous wires. The seat assembly of the present invention has no load transmitted through three-prong clips, and is easier to assemble because the lower sinuous wires may be secured to opposed sides of the frame before the coil springs are secured to the longer lower sinuous wires.

SUMMARY OF THE INVENTION

The present invention provides an improved seat assembly comprising a frame having four sides for supporting the assembly. The frame may be made of metal or wood or any other desirable material, including plastic. The seat assembly further comprises a plurality of clips attached to each side of opposed sides of the frame. A portion of each of the clips may be located in one of the openings in one of the sides of a metal frame.

The seat assembly further comprises a plurality of generally parallel upper sinuous wires. Each of the upper sinuous wires extends between opposed sides of the frame. In one embodiment, the upper sinuous wires extend generally parallel the sides of the frame. End portions of each of the upper sinuous wires are secured in opposed clips. Upper stabilizer wires extend transversely to the upper sinuous wires and are secured to the upper sinuous wires. In order to reduce noise due to metal-on-metal, each of the stabilizer wires may be coated in paper or plastic. In one embodiment, each of the stabilizer wires is secured to multiple upper sinuous wires with three-prong clips.

The seat assembly further comprises a plurality of generally parallel lower sinuous wires extending between opposed sides of the frame. In one embodiment, the lower sinuous wires extend generally parallel the sides of the frame and parallel the upper sinuous wires. End portions of each of the lower sinuous wires are secured in opposed clips. In one embodiment, each of the lower sinuous wires is bowed or arced in a downward direction, while each of the upper sinuous wires is bowed or arced in an upward direction.

The seat assembly further comprises a plurality of coil springs. Each coil spring has an upper end turn, a lower end turn and a plurality of central convolutions between the end turns. In one embodiment, the upper end turn of each coil spring is a knotted end turn, and the lower end turn of the coil spring is an unknotted end turn. In this embodiment, the diameter of the upper end turn of each coil spring is larger than the lower end turn of the spring. The upper end turn of each coil spring is secured to the upper stabilizer wires. The lower end turn of each coil spring is secured to one of the lower sinuous wires. The clips securing the upper and lower sinuous wires to opposed sides of the frame alternate along the front and rear of the frame.

The present invention provides an improved seat assembly which is easier to assemble than the previous version of the seat assembly. The improved seat assembly increases the structural integrity of the product. The improved seat assembly may be used with steel frames usable in motion furniture.

These and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of the embodiments given below, serve to explain the principles of the present invention.

FIG. 1 is a perspective view of a prior art seating product.

FIG. 1A is a perspective view of a portion of the prior art seating product of FIG. 1.

FIG. 2 is a perspective view of a seating product constructed in accordance with the present invention showing the environment of the seating product.

FIG. 3 is a perspective view of the seating product of FIG. 2.

FIG. 4 is a perspective view of a portion of the seating product of FIG. 3.

FIG. 5 is a cross-sectional view taken along the line 5-5 of FIG. 3.

FIG. 6 is a perspective view of another embodiment of seating product constructed in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

With reference to FIGS. 1 and 1A, there is shown a prior art seat assembly 10. The prior art seat assembly includes a rectangular frame 12, two coil springs 14, upper sinuous springs 16 secured to the frame 12 with clips 18, and lower sinuous springs 20. As best shown in FIG. 1A, each coil spring 14 is suspended by two lower sinuous springs 20. As best shown in FIG. 1A, each lower sinuous spring 20 is secured to the frame with a clip 22 at one end and with a different three-prong clip 24 at the other end. When a heavy load is placed on the seat assembly shown in FIGS. 1 and 1A, the load transfers through the coil springs to the bottom of the coil springs, through the three-prong clips to the lower sinuous wires and, ultimately to the rectangular frame. Since the seat load is ultimately borne by the bottom layer of sinuous springs, the weak point in the system is the three-prong clips 24.

FIG. 2 illustrates the seat assembly 26 of the present invention as used in a recliner 28 shown in phantom. Although the seat assembly 26 is illustrated being used in a recliner, the seat assembly 26 of the present invention may be used in any location in any piece of furniture.

The seat assembly 26 comprises a generally rectangular metal frame 30 having four sides: a front 32, a rear 34 and two opposed sides 36. In the illustrated embodiment, the frame 30 comprises two pieces; a generally U-shaped piece 38 and a linear rear piece 40 welded together. The generally U-shaped piece 38 comprises the front 32 and two opposed sides 36 of the metal frame 30. The linear rear piece 40 comprises the rear 34 of the metal frame 30. The metal frame 30 has a plurality of indentations 31 with openings 33 at different locations to assist in securing the frame 30 to different pieces of furniture. The illustrated indentations 31 and openings 33 are not intended to be limiting.

As shown in FIG. 5, the generally U-shaped piece 38 has a generally rectangular cross-section comprising a top wall 42, a bottom wall 44, an inner wall 46, and an outer wall 48 defining a hollow interior 50. As shown in FIG. 5, the linear rear piece 40 is generally L-shaped in cross-section, having a top wall 52 and a side wall 54 extending downwardly from an outer edge of the top wall 52.

As best shown in FIGS. 3-5, the side wall 54 of the linear rear piece 40 of frame 30 has a plurality of spaced openings 56 in the form of holes. As shown in FIG. 5, the outer wall 48 of the front 32 of the generally U-shaped piece 38 of frame 30 has a plurality of spaced openings 58 in the form of holes. The openings 56, 58 are spaced identically along the width of the front and rear 32, 34 of the frame 30 for purposes described below. In identical locations along the width of front and rear 32, 34 of the frame 30, clips 60 are secured inside the openings 58, 56, respectively. As shown in FIG. 5, a portion 62 of each clip 60 located along the front 32 of frame 30 resides inside the hollow interior 50 of the generally U-shaped piece 38. Similarly, a portion 62 of each clip 60 located along the linear rear piece 40 of frame 30 resides inside the side wall 54 of the linear rear piece 40. See FIG. 5.

As shown in FIGS. 2-5, the seat assembly 26 further comprises a plurality of generally parallel, upper sinuous wires 64. Each upper sinuous wire 64 has two opposed end portions 66, each end portion 66 being secured inside a hook portion 68 of one of the metal clips 60. The upper sinuous wires 64 are illustrated extending from front to back in the seat assembly 26. However, the seat assembly may be such that the upper sinuous wires 64 extend from side-to-side. As best shown in FIG. 5, each upper sinuous wire 64 is upwardly bowed to provide resilient support to loads placed on the seat assembly 26.

The seat assembly 26 further comprises a plurality of upper stabilizer wires 70. Each of the two upper stabilizer wires 70 shown in the embodiment illustrated extends transversely to the upper sinuous springs 64 and is fastened to each of the upper sinuous springs 64 with a fastener 72 in the form of a clip. Each of the upper stabilizer wires 70 is not connected to the frame 30 and extends less than the full width of the seat assembly 26. Each of the upper stabilizer wires 70 is preferably covered in paper or plastic to prevent squeaking or noise, i.e., metal-on-metal contact.

As shown in FIGS. 2-5, seat assembly 26 further comprises a plurality of generally parallel lower sinuous wires 74. Each lower sinuous wire 74 has two opposed end portions 76, each end portion 76 being secured inside a hook portion 68 of one of the metal clips 60. The lower sinuous wires 74 are illustrated extending from front to back in the seat assembly 26. However, the seat assembly may be such that the lower sinuous wires 74 extend from side-to-side. As best shown in FIG. 5, each lower sinuous wire 74 is downwardly bowed to provide resilient support to loads placed on the seat assembly 26 transferred through the coil springs 80. Unlike the prior art, each lower sinuous wire 74 extends the full length of the seat assembly 26 from the front 32 to the rear 34 of the frame 30, which reduces the number of potential weak points in the seat assembly. When a heavy load is placed on the seat assembly 26, the load transfers through the coil springs 80 to the bottom of the coil springs 80, to the lower sinuous wires 74 and, ultimately to the rectangular frame 30. Since the seat load is ultimately borne by the bottom layer of sinuous springs 74 which support the coil springs 80, the weak point in the system, the three-prong clips in the prior art has been eliminated, resulting in a stronger, more durable seat assembly.

As shown in FIG. 3, a plurality of coil springs 80 (two in the embodiment shown) are secured to the upper stabilizer wires 70 with fasteners 82, each fastener 82 being in the form of a three-prong clip. Each coil spring 80 is also secured to one of the lower sinuous wires 74 with two fasteners 84, each fastener 84 being in the form of a three-prong clip. Each coil spring 80 is made of one piece of wire and has an upper end turn 86, a lower end turn 88, and a plurality of central convolutions 90 between the end turns. In the embodiment illustrated, the upper end turn 86 is a knotted end turn, and the lower end turn is an unknotted end turn. In this embodiment, the diameter of the upper end turn 86 is greater than the diameter of the lower end turn 88. Although not shown, either of the end turns may be knotted or unknotted. The end turns may be any desired diameter, including the same diameter. Although the central convolutions 90 are illustrated decreasing in diameter from top to bottom, they may be any desired size or configuration, such as in an hourglass-shaped coil spring.

FIG. 6 illustrates another embodiment of seat assembly 92. The only difference between seat assembly 92 and seat assembly 26 is the frame. Instead of the metal frame 30 of seat assembly 26, seat assembly 92 has a generally rectangular wooden frame 94. The clips 60 may be secured to the wooden frame 94 in any known manner. The frame 94 has a front 96, a rear 98 and two opposed sides 100.

While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. For example, the coil springs may have a uniform diameter.

The invention in its broader aspects is, therefore, not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the general inventive concept.

Claims

1. A seat assembly comprising: a frame having four sides;a plurality of clips attached to each side of opposed sides of the frame;a plurality of generally parallel upper sinuous wires, each of the upper sinuous wires extending between the opposed sides of the frame, end portions of each of the upper sinuous wires being secured in opposed clips;a plurality of upper stabilizer wires extending transversely to and fastened to the upper sinuous wires;a plurality of generally parallel lower sinuous wires, each of the lower sinuous wires extending between the opposed sides of the frame, end portions of each of the lower sinuous wires being secured in opposed clips;a plurality of coil springs, each coil spring having an upper end turn, a lower end turn and a plurality of central convolutions between the end turns, the upper end turn of each coil spring being secured to the upper stabilizer wires and the lower end turn of each coil spring being secured to one of the lower sinuous wires, wherein the clips securing the upper and lower sinuous wires to the opposed sides of the frame alternate along the opposed sides of the frame.

2. The seat assembly of claim 1 wherein each of the stabilizer wires is coated to prevent wire-on-wire noise.

3. The seat assembly of claim 1 wherein each of the coil springs has upper and lower end turns of different diameters.

4. The seat assembly of claim 1 wherein each of the coil springs has a knotted upper end turn.

5. The seat assembly of claim 1 wherein each of the coil springs has an unknotted lower end turn.

6. The seat assembly of claim 1 wherein only the lower end turn of each of the coil springs is secured to one of the lower sinuous wires.

7. A seat assembly comprising: a frame having four sides;a plurality of clips attached to opposed sides of the frame;a plurality of generally parallel upper sinuous wires, each of the upper sinuous wires extending between the opposed sides of the frame, end portions of each of the upper sinuous wires being secured in opposed clips;a plurality of upper stabilizer wires extending transversely to and fastened to the upper sinuous wires;a plurality of generally parallel lower sinuous wires, each of the lower sinuous wires extending between the opposed sides of the frame, end portions of each of the lower sinuous wires being secured in opposed clips;a plurality of coil springs, each coil spring having an upper end turn, a lower end turn and a plurality of central convolutions between the end turns, the upper end turn of each coil spring being secured to the upper stabilizer wires and the lower end turn of each coil spring being secured to one of the lower sinuous wires, wherein only the lower end turn of each of the coil springs is secured to the sinuous wires.

8. The seat assembly of claim 7 wherein each of the stabilizer wires are coated to prevent wire-on-wire noise.

9. The seat assembly of claim 7 wherein each of the coil springs has upper and lower end turns of different diameters.

10. The seat assembly of claim 7 wherein each of the coil springs has a knotted upper end turn.

11. The seat assembly of claim 7 wherein each of the coil springs has an unknotted lower end turn.

12. The seat assembly of claim 7 wherein the clips securing the upper sinuous wires and the clips securing the lower sinuous wires alternate along the opposed sides of the frame.

13. A seat assembly comprising: a frame;a plurality of clips secured to each side of opposed sides of the frame;a plurality of generally parallel upper and lower sinuous wires, each of the upper and lower sinuous wires extending between two of the clips;a plurality of upper stabilizer wires secured to the upper sinuous wires;a plurality of coil springs, each coil spring having an upper end turn, a lower end turn and a plurality of central convolutions between the end turns, the upper end turn of each coil spring being secured to the upper stabilizer wires and the lower end turn of each coil spring being secured to one of the lower sinuous wires, wherein the upper and lower sinuous wires alternate longitudinally along the opposed sides of the frame.

14. The seat assembly of claim 13 wherein each of the stabilizer wires are coated to prevent wire-on-wire noise.

15. The seat assembly of claim 13 wherein each of the coil springs has upper and lower end turns of different diameters.

16. The seat assembly of claim 13 wherein each of the coil springs has a knotted upper end turn.

17. The seat assembly of claim 13 wherein each of the coil springs has an unknotted lower end turn.

18. The seat assembly of claim 13 wherein only the lower end turn of each of the coil springs is secured to the sinuous wires.