Bed mattress and method of manufacturing the same

A bed mattress of a mattress body having a spring frame with several springs disposed with a certain intervals therein, two pad layers on the top and bottom sides of said spring frame and at least one cushion member disposed on either or both surfaces of said two pad layers, further comprising; a foam-molded wall member for surrounding said mattress body; and a mattress cover for covering the structural body of said mattress body and said wall member, for simplifying the process of manufacturing the bed mattress, and enhancing workability and productivity is disclosed.

DETAILED DESCRIPTION FOR PREFERRED EMBODIMENT Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the embodiment will be described for illustrative purposes only so that those skilled in the art can easily work the present invention and does not limit the technical spirit and scope of the invention. As shown in FIGS. 2, 3 and 5 , a bed mattress according to an embodiment of the present invention comprises a spring frame 50 in which springs 50 ′ made of metal wires are kept at regular intervals between upper and lower spring rims 51 such that the springs 50 ′ can perform a function of absorbing external shock or vibration; pad layers 52 of a felt fabric mounted on the respective top and bottom sides of the spring frame 50 and two cushion members 53 and 53 ′ of a sponge sheet bonded to the surface of the pad layers. The pad layer and the sponge sheet are preferably to have a thickness of 15 to 25 mm and 25 to 35 mm respectively, while it is preferable that a high density sponge sheet is used on one side and a low density one is used on the other side. Further, the spring frame 50 , the pad layers 52 and the cushion member 53 are enveloped by only one mattress cover. As already described with reference to FIG. 1, a mattress body as a combination of the spring frame, pad layers and cushion member(s) are known in the art. According to a preferred embodiment of the present invention, there is provided a bed mattress comprising a spring frame 50 ; a wall member 55 which is formed through a foam molding process and coupled with the mattress body as a combination of the spring frame 50 , the pad layers 52 and 52 ′ and the cushion members 53 and 53 ′ by enveloping four peripheral sides of the mattress body therein and a mattress cover having upper and lower cover sheets 54 ′ and 54 ″ which can hold the structural elements of the mattress therein. Hereinafter, a method of manufacturing the bed mattress according to the present invention will be explained in detail with reference to the accompanying drawings. As schematically shown in FIGS. 2 ˜ 4 , an isolating sheet 56 preferably made of a non-woven fabric was fixed to the four peripheral sides of the spring frame 50 . The pad layers 52 having a predetermined thickness were bonded to the top and bottom sides of the spring frame 50 . The cushion member 53 of a low density sponge sheet was bonded to the surface of the upper pad layer 52 , whereas the cushion member 53 ′ of a high density sponge sheet was bonded to the surface of the lower pad layer 52 ′. Since the cushion members 53 and 53 ′ having resiliences different from each other were bonded to the upper and lower pad layers 52 and 52 ′ in such a way, two types of cushioning feelings, soft or hard, could be provided by one mattress. Then, the mattress body A in which the pad layers 52 and 52 ′ and the cushion members 53 and 53 ′ were bonded to the top and bottom surfaces of the spring frame 50 was secured into a foaming mold 57 with the top thereof being opened. Since there was a difference in sizes between the mattress body A and the mold 57 , a space B was defined around between the peripheral sides of the mattress body A and the inner walls of the mold 57 . Thereafter, the top of the mold 57 was covered with a cover 58 that could open and close the mold 57 , and the cover was locked and fixed to the mold. Then, a foaming material was injected into the space B defined between the mattress body A and the mold 57 through injection holes 60 formed through the cover 58 and was foamed to allow a wall member 55 to be molded in the space. As the wall member 55 was cured, it was integrally coupled with the mattress body of the spring frame 50 , the pad layers 52 and the cushion members 53 and 53 ′. As such, when the wall member 55 was form-molded, the isolating sheet 56 surrounding the four peripheral sides of the spring frame 50 prevented the foaming material from being introduced into the space in the spring frame 50 and adhering to the springs 50 ′. Thereafter, the integrally molded structure obtained in such a manner was covered with the upper and lower cover sheets 54 ′ and 54 ″. The upper cover sheets 54 ′ was put on the top and four peripheral sides of the integrally molded structure, while the bottom side thereof was held by the lower cover sheet 54 ″. Then, after the rim of the upper cover sheet 54 ′ was brought into contact with the rim of the lower cover sheet 54 ″, the overlapped portions of the two cover sheets was stitched together with a rim 61 . Thus, the manufacture of the mattress was completed. Although the spring frame, felt fabrics, sponge sheets, etc. were utilized as the structural elements of the mattress in the preferred embodiment of the present invention, some of them may not be used or may be replaced by the other materials. Further, it is apparent that the material or the structure of the cover may be modified, while the isolating sheet may not be used if the wall member is foam-molded separately for being assembled with the mattress body thereafter. According to the present invention, the perimeter or the four peripheral sides of the combined structure formed by bonding the cushion members such as sponge sheets to the top and bottom sides of the spring frame are surrounded by the foam-molded wall member. Then, the integrally molded structure obtained as such is covered with only the upper and lower cover sheets which in turn are stitched together. Thus, the process of manufacturing the bed mattress is greatly simplified, and workability and productivity are enhanced. Accordingly, since the throughput of the mattresses per unit time is increased, the mattress can be mass-produced and production costs thereof can be reduced. In addition, since the conventional side sheets need not to be used and the structural members of the mattress can be enveloped by only one cover, the portion to be stitched can be minimized to one portion. Thus, the manual works needed for making the fine appearance of the stitched portions are reduced and bed mattresses with a better appearance can be obtained.