SEAT CONSTRUCTION

Abstract: A self-contained and self-supporting wire suspension system is provided for use within a seat construction. The system includes at least one bolster wire, a set of parallel stringer (116) wires wrapped around the bolster wire(s) (122), and a pair of parallel border wires (112) secured to the free ends of the stringer wires. The system further includes a top or seat supporting portion defined by the segments of the stringer wires which extend between the bolster wire and one border wire. A leg portion (124) is defined by stringer wire segments extending between the bolster wire and the other border wire. The border wires are secured to a support surface or a wire frame. The stringer wires may be embedded within a plastic foam seat cushion.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention. The field of the invention relates to seat construc­ tions for motor vehicle seats and the like. 2. Brief Description of the Prior Art. Supporting spring structures for seating assemblies have commonly included load-bearing wires supported by spring elements or the like. U.S. Patent No. 3,639,002, which is incorporated by reference herein, discloses such a structure. A plurality of transversely extending wires are each double wrapped about a pair of parallel, longitudinally extending wires. Free ends of the transversely extending wires extend beyond the longitudinal wires at an angle with respect to the plane defined thereby. An additional wire connects the free ends. The entire assembly may be supported by a cantilevered spring structure and embedded in foam. U.S. Patent Nos. 2,934,133, 3,248,745 and 4,325,542 are representative of other spring seat constructions known to the art. The construction disclosed in the latter patent has the advantage of inherently retaining its assembly to a seat frame without requiring additional components for installation or support. SUMMARY OF THE INVENTION A self-contained seat suspension unit is provided which is easily installed, requires only a flat mounting surface, and is stable in all types of seat frames. The unit includes a plurality of stringer wires which run substantially parallel to each other. The stringer wires are wrapped about at least one bolster wire and have free ends secured to border wires. In a preferred embodiment of the invention, the border wires are secured to opposite sides of a wire frame. The bolster wire is closer to one border wire than the other, thereby defining a front leg portion of the suspension unit. The stringer wires are contoured to support the thighs of a person in a comfortable seating position. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partially cutaway perspective view of a seat construction including a suspension system according to the invention; and Fig. 2 is a perspective view of the suspension system partially shown in Fig. 1. DETAILED DESCRIPTION OF THE INVENTION Fig. 1 illustrates a bench type motor vehicle seat construction 100 which includes a self-contained and self-­ supporting suspension system 110 as discussed hereinafter. Fig. 2 illustrates the wire frame suspension system 110 for the rear seat of a motor vehicle. The system includes a substantially rectangular wire frame 112, the ends of which are bent inwardly and secured by a clamp 114. Two generally U-shaped rear feet 112A and one generally U-shaped front foot 112B are defined by the frame 112. Each foot may be secured to the floor of the motor vehicle. A plurality of thirteen gauge stringer wires 116 extend longitudinally with respect to the wire frame 112 and are substantially parallel to each other. They are equally spaced about one to two and one-half inches apart. The wires are contoured to provide adequate support for a person's thighs. A first border wire 118 is secured to the rear end of the frame 112 by a pair of clamps 114. A second border wire 120 is clamped to the front and of the frame 112. A bolster wire 122 is positioned above and parallel to the second bolster wire 120. Each border and bolster wire is constructed from twelve gauge, oil-tempered wire encapsulated by an extruded coating of high density poly­ ethylene. The stringer wires are double wrapped about the first border wire and the bolster wire and single wrapped about the second border wire. The second border wire and the bolster wire are positioned such that the front leg portion 124 defined by the stringer wires 112 extends at an acute angle with respect to the stringer wires defining the thigh supporting portion 126A of the upper surface 126 of the suspension system 110. This provides the necessary resilience at the front end of the vehicle seat. Because the system 110 is intended to be self-support­ ing, the stringer wires 116 are constructed from thirteen gauge wires (ASTM standards) to provide the required stability and resilience. Fourteen gauge wires, as employed in the construc­ tion disclosed in U.S. Patent No. 3,639,002, fail to provide adequate support. Twelve gauge wire is too stiff for the intended application and could possibly be felt through the seat in the absence of an insulator. Since an object of the invention is to provide seating comfort while also minimizing the number of parts, the weight, and the cost of the seat construction, stringer wires much heavier than thirteen gauge would not be suitable. The border and bolster wires are each made from twelve gauge wire. The plastic coating about the bolster wire and the first border wire 118 is considerably thicker than that about the border wires due to the relatively wide double wrapping of the stringer wires thereabout. A coating of about 0.07 inches has been successfully employed. Since the system must be able to support considerable weight and pass rigorous cycle testing involving repeated applications of a load, it is important for the areas subject to the most stress to be sufficiently durable. The double wrapping of the stringer wires about the bolster wire is sufficiently wide that it has such durability. In a preferred embodiment of the invention, the outside diameter of the wrapping was 0.43 inches. This is substantially wider than the 0.32 inch wrapping in structures as shown in the aforementioned U.S. Patent No. 3,639,002. Tests indicated the tighter wrapping would result in snapped stringer wires after repeated load applications. Using the preferred thirteen gauge wires, the outside diameter of the double wrappings about the bolster wire should be at least about 0.37 inches. The coated bolster wire has a sufficient diameter that the stringer wires are wrapped fairly snugly thereabout. It will be appreciated by those skilled in the art that the suspension system provided herein has many applications and can be adapted for use in many types of vehicle seats. While neither twelve nor fourteen gauge wire has been found to be suitable for the system, the wire may be somewhat lighter or heavier than thirteen gauge and still provide adequate perfor­ mance. It would also be possible to include, in alternating sequence or otherwise, stringer wires of various gauges with the preferred thirteen gauge wire.

Claims: 1.A self-contained, self-supporting and resilient suspension system (110) for a seat construction comprising: a generally rectangular wire frame (112); first and second substantially parallel border wires (118,120) secured, respectively, to opposite sides of said wire frame; a plurality of substantially parallel stringer wires (116) extending between and secured to said border wires; a bolster wire (122) extending substantially parallel to and above a plane defined by said first and second border wires, each of said stringer wires being wrapped about said bolster wire, said bolster wire being substantially closer to said second border wire than said first border wire; said stringer wires extending between said bolster wire and said first border wire defining a leg portion (124) of said suspension system; and said stringer wires extending between said bolster wire and said first border wire (118) defining a seat supporting portion. 2. A system as defined in claim 1 wherein a plurality of said stringer wires are made from oil-tempered, thirteen gauge wires. 3. A system as defined in claim 2 wherein said leg portion extends at an acute angle with respect to said seat supporting portion at said bolster wire. 4. A system as defined in claim 3 wherein said seat supporting portion is contoured to provide thigh support adjacent to said bolster wire. 5. A system as defined in claim 2 wherein said wire frame includes an integrally formed, generally U-shaped foot extending beneath one of said first and second border wires. 6. A system as defined in claim 2 wherein each of said stringer wires is double wrapped about said bolster wire, the outside diameter of said double wrappings being at least 0.37 inches. 7. A system as defined in claim 2 wherein each of said stringer wires is double wrapped about said bolster wire and said first border wire, the outside diameter of said double wrappings being at least 0.37 inches. 8. A system as defined in claim 7 wherein each of said stringer wires is single wrapped about said second border wire.

Inventors: COJOCARI, BRIAN S., SHIVERS, JOSEPH R.
Applicants: WICKES MANUFACTURING COMPANY
Application year: 1988
Main classification: A47C7
IPC codes: A47C7