BED MAT

Abstract: This invention relates to a bed mat. A mat main body comprises a core material (3) made of a rigid foamed material having a sufficient thickness, protective sheet members (4), (5) placed on the front and reverse surfaces of the core material while sandwiching the core material (3) between them and surface layer materials (6), (7) made of a cushion material and put on the protective sheet material (4), (5). At least one of the surface layer materials (6), (7) is formed by superposing a second cushion layer (11) made of a semi-rigid cushion material having a corrugated surface (13) on its surface on a first cushion layer (10) made of a soft cushion material. A conventional bed mat has a structure incorporating a plurality of coil springs fixed to a metal frame, and is not free from problems that the total weight is heavy and the mat is difficult to handle. In accordance with the present invention, the rigid foamed material is used as the core material (3) without using the metal member. Therefore, the mat of the present invention is light in weight and is free from problems such as rust and breakage. Moreover, since the corrugated surface (13) of the second cushion layer (11) in the surface layer material supports the body in a point contact state, air permeability is high and finger-pressure action is provided to promote health.

Description: TECHNICAL FIELD The present invention relates to a mattress. Particularly, it relates to a mattress wherein metal component parts such as coiled springs are not incorporated. TECHNICAL BACKGROUND Conventionally, the mattress has a structure wherein multiple coiled springs are fixed on the metal frames to both upper and lower sides, and sheeting materials are laid over it, then enclosing the entire body with a covering cloth. This kind of mattress contains metal frames and a multitude of coiled springs, which makes it very heavy and inconvenient to handle. Moreover, coiled springs and metal frames generate rust and cause breakage of and damage to the sheeting and covering cloth, often causing a short life of the mattress and have a bad influence on the comfortableness of the mattress in use. Furthermore, in this kind of mattress too much emphasis is placed only to sustaining user's body stably, and attention is barely paid to promoting the users' health. The present invention avoids using metal components, and by employing rigid foam as the core material and by piling surface layer materials consisting of cushioning materials over the core material, it makes the mattress light in weight and of long life, besides improving comfortableness in use of this mattress. A mattress which avoids the use of metal components such as coiled springs is known from GB-A-1 304 373. This prior art describes in particular an orthopaedic mattress which comprises a central panel or board of stiff or firm construction and layers of resilient foamed plastics materials bonded one to each face of the panel or board to provide some degree of comfort whilst the central panel or board acts as a flat support preventing or minimizing undesirable posture. This mattress, with a cover sheet enclosing the mattress, which essentially is a hard one, is intended as a rigid support for persons suffering from back-ache. Thus the mattress according to the above prior art addresses itself to the solution of a problem which resides in bringing relief from pain to persons suffering from back-ache. The above prior art is, however, totally silent in respect of the problems underlying the present invention and discussed herein. DISCLOSURE OF THE INVENTION The mattress in accordance with the present invention is a cushioning mattress comprising a layered construction with a central part formed of a rigid foam material with a particular thickness, first and second protective plates arranged respectively on upper and lower sides of said central part and upper and lower surface layers consisting of a cushioning material arranged one on each of the said protective plates and a cover in sheet form enclosing the entire mattress, characterized in that said upper surface layer has an outer undulating surface comprising an array of projections each having at the top a hardened portion which has been produced by a hardening process. Thus, the mattress in accordance with this invention uses no metal component parts such as coiled springs and employs rigid foam as the core material in the main body, which contributes to reducing the weight of the mattress, making it convenient to handle. There is no problem of rusting and breaking, and the mattress thus endures a long life. Moreover, no bad influence is seen on the comfort of the mattress in use. In addition, since the core material is covered by the protecting plates, there is no risk of the core material being damaged by an external force, making the mattress superior in its endurance. Moreover, as the protecting plates have the function of preventing the user's body from sinking into the mattress, the body is sustained in a natural form to assure sound sleeping. According to the accompanying embodiment, the first cushioning layer gives appropriate cushion to the body, and the second cushioning layer sustains the body with contacting spots on its undulating (up-and-down) surface, assuring space for excellent ventilation and damp releasing performance to secure a comfortable feeling in use. In addition, finger-pressing massaging effect with the projecting parts will affect the body to help good blood circulation and to promote health. BRIEF DESCRIPTION OF THE INVENTION Fig. 1 is a perspective view of the mattress according to one embodiment of the invention with a part of the cover broken away. Fig. 2 is a cross-sectional view taken along the line II-II in Fig. 1. Fig. 3 is a perspective view of all layers making up the mattress, with a part of each layer broken away. Fig. 4 is a cross-sectional view of the second cushioning layer that is magnified. Fig. 5 is a perspective view showing a part of the cover of the mattress broken away in accordance with another embodiment of the invention. PREFERRED FORM FOR THE EMBODIMENT OF THE INVENTION Figs. 1 and 2 show a mattress relative to an embodiment in accordance with the present invention, wherein the entire external contour of the main body of a cushioning mattress is enclosed in a cover 2 of sheet form. As shown in Figs. 2 and 3, the main body of said mattress 1 is constructed with the core material 3 as the middle layer, on both sides of which protective plates 4 and 5 are placed. Surface layer material 6 and 7 is placed on and respectively covers the protective plates 4 and 5 and the external vertical sides are covered with peripheral wall material 8. Adhesives are used between the core material 3 and each protective plate 4 and 5, between each protective plate 4 and 5 and surfacing layer materials 6 and 7, and between this laminated body and external wall material 8 to bond them together into one unit. The core material 3 is made of light weight rigid foam material, it is set to form about 1/2 in proportion to thickness of the mattress. The core material contributes not only to reduce the weight of the mattress, but also it has the function of avoiding deformation of the mattress as a whole, maintaining the thickness of the mattress. A multiple number of ventilation holes 9 are bored on both sides of the core material 3, avoiding the damp air from staying put within the main body of the mattress. The protective plate 4 on the surface side employs strong and difficult to deform compressed plywood of several mm thickness and will prevent the core material from forcibly breaking down under the load of the weight of human body and help avoid the body from sinking into deformed elasticity of the surface layer material 6. As for the protecting plate 4, a corrugated plastic plate may be also used instead of the above-mentioned compressed plywood, as far as it has a sufficient strength. The protective plate 5 on the back side is for protecting the core material 3, in the same way as the protective plate 4 on the surface side. In the case of this embodiment, however, a light-weight and damp-absorbing paper board may be used, although it is inferior in strength, because the up-and-down sides are predetermined for this embodiment. In this embodiment, the surface layer material 6 on the upper side uses a cushioning material in 3 layers of different kind. The structure is of 3 layers; the first cushioning layer 10 is the lower most layer, the uppermost layer being the second cushioning layer 11, and the middle layer is the third cushioning layer 12. The first cushioning layer 10 is made of a flexible and ventilating cushioning material such as flexible polyurethane foam and gives strong cushioning effect to the user's body by sufficiently deforming as an elastic layer under the load. The second cushioning layer 11 is made of a rather weak cushioning quality material and concurrently of an appropriate rigidity but having a semi-rigid cushioning material like semirigid urethane foam that is provided with ventilating property which sustains the human body by deforming in a small way under the load. For this cushioning material, for instance, "RUBBERTAN H", a product by Toyo Rubber Chemical Industry Co. Ltd., Made from polyether and rubber as the main raw material, is suitable. On its entire surface, and undulating surface 13 is formed. Solidified hardened portions 15 are provided on each projection on this surface 13, as shown in Fig. 4 and the hardened portions 15 are made by impregnating rubber liquid or the like at the top of the projection 14 and then solidified by subjecting to heating process at about 100° to vulcanize the rubber liquid part. By dint of this hardened portion 15, the projection 14 will not be squashed under the load and the body can be sustained in a condition of contact with points, thus generating space between the body and the cushioning material for good ventilation and giving finger-pressing massaging effect. The third cushioning layer 12 is formed by compressing urethane chip at a high temperature and has a medium degree of cushioning property to support the body and reinforce the strength of the surface material 6. The back side surface material 7 and the peripheral vertical wall material 8 is of the same material as the above-mentioned first cushioning material. The surface layer material 6 gives a forceful cushioning by sufficiently deforming under the load. The peripheral vertical wall material 8 protects the laminated structure of the mattress from the outside force. Fig. 5 shows another embodiment of the invention and represents a mattress provided with a multiple number of permanent magnets 16 on the upper side surface layer material 6. By applying magnetic line of force to the body, these permanent magnets 16 are intended to obtain a certain defined magnetic therapeutical effect. They are fixed with adhesives at the dented portion of the undulating surface 13 in the second cushioning layer 11. UTILITY IN APPLICATION TO INDUSTRIES The mattress in accordance with this invention is installed on a bed and is used with covering of the bed sheet. When a user lies on this mattress, mainly the surface layer material 6 of the first cushioning layer 10 at the upper side and the surface layer material 7 at the lower side give the cushioning effect and the second cushioning layer 11 supports the body. In this case, the protective plate 4 prevents the body from sinking in unnatural shape due to the elastic deformation of the main body of the mattress. Furthermore, the second cushioning layer 11 is provided with the hardened portion 15 at the top of the projection 14 on the undulating surface 13, and each projection will not be squashed under the load of body and the body is supported by the hardened portions 15 of the projections 14 with contact points. For this reason, the vacant space between the body and the cushioning layer 11 of the second cushioning layer is kept to assure ventilation and damp releasing, promoting a comfortable feel in use. Moreover, each projection 14 on the undulating surface 13 will press appropriate portions of the body, giving a finger-pressing massaging effect and encouraging blood circulation to help promote the health. In an embodiment as shown in Fig. 5, the magnetic line of force radiating from the permanent magnets 16 will affect the human body and further promotes the blood circulation, to eliminate stiffness of muscles and to recover from fatigue. For transporting this mattress, the weight is reduced with no metal components used in the main body 1 and rigid foam material used, so the handling is very easy. There is no risk of generating any rust and inviting damage, and the mattress is superior in endurance and gives excellent feel in use.

Claims: A cushioning mattress comprising a layered construction with a central part (3) formed of a rigid foam material with a particular thickness, first and second protective plates (4, 5) arranged respectively on upper and lower sides of said central part (3) and upper and lower surface layers (6, 7) consisting of a cushioning material arranged one on each of the said protective plates (4, 5) and a cover in sheet form enclosing the entire mattress, characterized in that said upper surface layer (6) has an outer undulating surface (13) comprising an array of projections (14) each having at the top a hardened portion (15) which has been produced by a hardening process. A mattress according to claim 1, wherein the said upper surface layer (6) comprises at least two cushioning layers (10, 11), whereby the first cushioning layer (10) consists of a flexible cushioning material and the second cushioning layer (11), which is arranged over the first cushioning layer (10), consists of a semi-rigid cushioning material and is provided with said outer undulating surface (13). A mattress according to claim 2, wherein the said upper surface layer (6) comprises a third cushioning layer (12) which is interposed between the first and second cushioning layers (10, 11), respectively, and formed by compressing urethane chip at a high temperature to reinforce the strength of the said surface layer (6). A mattress according to claim 1, wherein said central part (3) is provided with a plurality of ventilation holes within in its interior. A mattress according to claim 1, wherein the said at least one surface layer (6) is provided with a plurality of permanent magnets (16) on its surface.

Inventors: MASUDA ISAMU, MASUDA, ISAMU
Applicants: NIHON KENKOZOSHIN KENKYUKAI KK, NIHONKENKOZOSHINKENKYUKAI CO. LTD.
Application year: 1989
Main classification: A47C27
IPC codes: A47C27