Resin cushioning element

[0002] 1. Field of the Invention

[0003] The present invention is directed to a element for mattresses, made of resin.

[0004] 2. Description of the Related Art

[0005] A conventional resin cushioning element of the type is disclosed in, for example, U.S. Pat. No. 5,588,165. This resin cushioning element is formed of plastic and forms axially-oriented through chambers having ribs. When a load is applied on a top of the conventional resin cushioning element, the cushioning element deforms similar to a wire coil spring.

[0006] However, the foregoing conventional resin cushioning element has the inner ribs, so an inner structure of a cavity of a mold assembly becomes complex.

[0007] U.S. Pat. No. 5,787,533 also discloses another conventional resin cushioning element. However, this is similar to the foregoing conventional resin cushioning element in structure. Thus, complexity of the mold assembly is still a problem.

[0008] Accordingly, a need exists for a resin cushioning element without the foregoing drawback.

[0009] The present invention has been developed to satisfy the need noted above and thus has a primary object of providing a resin cushioning element which is of one-piece construction comprising upstanding and downstanding portions alternately arranged in a regular manner to form a matrix having four peripheral surfaces.

[0010] The above and other objects, features and advantages of the present invention will be more apparent and more readily appreciated from the following detailed description of preferred exemplary embodiments of the present invention, taken in connection with the accompanying drawings, in which;

[0011] FIG. 1 is a top view of a resin cushioning element in accordance with a first embodiment of the present invention;

[0012] FIG. 2 is a side view of the resin cushioning element as viewed from the bottom in FIG. 1;

[0013] FIG. 3 is a side view of the resin cushioning element as viewed from the right in FIG. 1.

[0014] FIG. 4 is a cross-sectional view of the resin cushioning element taken along line C—C in FIG. 1;

[0015] FIG. 5 is a cross-sectional view of the resin cushioning element taken along line D—D in FIG. 1;

[0016] FIG. 6 is a top view of a resin cushioning element in accordance with a second embodiment of the present invention;

[0017] FIG. 7 is a side view of the resin cushioning element as viewed from the bottom in FIG. 6;

[0018] FIG. 8 is a side view of the resin cushioning element as viewed from the right in FIG. 6;

[0019] FIG. 9 is a cross-sectional view of the resin cushioning element taken along line A—A in FIG. 6;

[0020] FIG. 10 is a cross-sectional view of the resin cushioning element taken along line B—B in FIG. 6;

[0021] FIG. 11 is an outline view showing a cushion support as an arrangement of the cushioning elements in the form of a matrix; and

[0022] FIG. 12 is a top view of a cover assembly in which the cushion support shown in FIG. 11 is accommodated to constitute a mattress.

[0023] Preferred embodiments of the present invention will be described hereinafter in detail with reference to the accompanying drawings.

[0024] First of all, with references to FIGS. 1-5, there is illustrated a resin cushioning element 1 which is of one-piece construction. The resin cushioning element 1 includes cushioning portions 2 which are arranged regularly to constitute a matrix which is generally rectangular with five cushioning portions 2 in an X-direction and five cushioning portions 2 in a Y-direction.

[0025] The cushioning portion 2 is in the form of a convex or upstanding portions 2awhen extending in the upward direction, while the cushioning portion 2 is in the form of a concave or downstanding portion 2bwhen extending in the downward direction. The upstanding portions 2aare identical in dimension, while the downstanding portions 2bare also identical in dimension. The upstanding portion 2adiffers from the downstanding portion 2bonly in the extending direction.

[0026] As a raw material of the resin cushioning element 1, which is of one-piece construction, a thermoplastic polyester elastomer is used which is supplied from TOYOBO under the name “PELEPRENE”®. Employing such a resin cushioning element 1 allows the same to be washed. The upstanding portion 2ais in the form of a hollow structure with its lower end open, while the downstanding portion 2bis in the form of a hollow structure with its upper end open. A preferred profile of each of the upstanding portion 2aand the downstanding portion 2bis a trapezoid. Making each of the upstanding portion 2aand the downstanding 2binto such a simple shape allows that when vertical forces are applied to the upstanding portion 2aand the downstanding portion 2bthe resultant stresses diverge, thereby preventing stress concentrations. Such a simple shape of the cushioning element 1 which is of one-piece construction, has a result that the required molding device becomes more simple than the conventional one.

[0027] FIGS. 4 and 5 depict a series of the cushioning portions 2 wherein the upstanding portions 2aalternate with the downstanding portions 2band another series of the cushioning portions 2 wherein the upstanding portions 2aalternate with the downstanding portions 2b,respectively, in such a manner that both series are out of phase by a half cycle (180 degrees). Because of this structure, the cushioning elements 1 can be stacked on one another. The softness can be adjusted according to the number of stacked cushioning elements 1.

[0028] The cushioning elements 1 have four peripheral surfaces: a pair of parallel lengthwise peripheral surfaces and a pair of parallel lateral peripheral surfaces. Along one of the lengthwise peripheral surfaces and the other of the lengthwise peripheral surfaces, a plurality of equally spaced connecting portions 3aand a plurality of equally spaced connecting portions 3bare provided, respectively. The connecting portion 3ahas a hole 3aaand the connecting portion 3bhas an integral upstanding pin 3bb.The pins 3bbof the cushioning element 1 are fitted, when another cushioning element is adjacent thereto, in the corresponding holes 3aathereof. Employing such an engagement between two adjacent cushioning elements 1 allows construction of a cushion support 100 as shown in FIG. 11, and accommodating the resultant cushion support 100 is a cover assembly 110 establishing a mattress 120. The cover assembly 110 includes a base portion 119, a top portion 111, and a side wall portion 115 connecting therebetween. The top portion 111 is adhered at an inner side with two layered pad portions 112 and 113, which are mounted on the cushion support 100.

[0029] It is to be noted that adjusting the number of cushioning elements 1 can vary the longitudinal length and/or the lateral length depending on the demand. Of course, depending on this the dimensions of the cover assembly 110 can be adjusted. The cushion support 100 is an assembly of one-piece resin cushioning elements 1, which means that if the mattress 120 has to be shipped from the factory to another place, such shipment can be performed easily. The reason is that in such a shipment the cover assembly is handled in an expanded state in the form of the stacked cushioning elements 1. Thus, unlike conventional mattress shipment, the mattress 120 of the present invention is less bulky.

[0030] Instead of the trapezoid upstanding portion 2a(downstanding portion 2b), the hollow upstanding portion 2a(downstanding portion 2b) can be profiled in the shape of a dome which is constituted by a cross member. The dome has four angularly spaced apertures which allows the hollow upstanding portion 2a(downstanding portion 2b) to deform like a spring without concentrated stress. Upon piling the cushioning elements 1, a circular projection at a top of the lower sided dome receives an elastic portion in an upper sided dome, thereby preventing separation.

[0031] The invention has thus been shown and described with reference to specific embodiments, however, it should be understood that the invention is in no way limited to the details of the illustrated structures but changes and modifications may be made without departing from the scope of the appended claims.