AIR MATTRESS

Abstract

 An air mat (20) includes cells (21, 22, 23) arranged in a longitudinal direction of the air mat. Each cell (21, 22, 23) is bag-shaped and made of a plastic sheet. Each cell (21, 22, 23) includes an air supply port (21a, 22a, 23a) for supplying air into the cell. The cells (21, 22, 23) include at least one specific cell (S) that corresponds to the buttocks (G) of a user (U) and non-specific cells (NS) other than the specific cell (S). The air mat (20) further includes a first air supply system (60) that is connected to the air supply port of the specific cell (S) to supply air to the specific cell (S) and a second air supply system (70) that is connected to the air supply ports of the non-specific cells (NS) to supply air to the non-specific cells (NS).

Description

TECHNICAL FIELD

[0001] The present invention relates to an air mat.

BACKGROUND ART

[0002] Various attempts have been made with conventional air mats to prevent bedsores in the users who lie on the mats over a prolonged period. For example, Patent Document 1 discloses an air mat that includes a plurality of air cells extending in the width direction of the air mat. The air cells are arranged in the longitudinal direction of the air mat and coupled to one another. Each air cell includes a first cell, which is shaped as an elongated bag and filled with air, and second and third cells, each of which has a diameter that is half the diameter of the first cell and a length that is equal to the length of the first cell. The second and third cells are arranged side by side and fused to the upper surface of the first cell. When the air mat receives a load while in use, the second and third cells of the air cells move outward. This enlarges the area of contact between the air mat and the body surface of the user and reduces the contact pressure, limiting development of bedsores.

[0003] Patent Document 2 discloses an air mat that includes a plurality of air cells extending in the width direction of the air mat. The air cells are arranged in the longitudinal direction and coupled to one another. Each air cell includes cells in three layers of upper, middle, and lower layers. The cell in the upper layer communicates with the cell in the middle layer. The air mat further includes a supply and exhaust pump, first and second system tubes, which connect the pump to the cells, sensors, which detect the pressure of the air cells of the respective systems, an input device, which is used to input the weight of a user, and a control circuit, which controls the pump according to the input from the sensors and the input of weight. The structure prevents the mat from sinking deeper when a heavier person lies on the mat than when a lighter person lies on the mat.

PRIOR ART DOCUMENTS

Patent Documents

[0004] 

Patent Document 1: Japanese Laid-Open Patent Publication No. 2008-125798

Patent Document 2: Japanese Laid-Open Patent Publication No. 2011-160896

SUMMARY OF THE INVENTION

Problems that the Invention is to Solve

[0005] However, the conventional air mats formed by multiple cells have following problems. That is, when the upper body of the user of the air mat is raised, most of the load of the entire upper body of the user is applied to the cells corresponding to the buttocks of the user (hereinafter referred to as specific cells) among the cells. Therefore, the air in the specific cells flows out, and the outflowing air flows into other cells coupled through a tube. This reduces the amount of air in the specific cells, so that the buttocks of the user may bottom out.

[0006] For this reason, when the upper body of the user is raised, the conventional air mat supplies air to the specific cells corresponding to buttocks from an air supply device so as to limit such bottoming out of the buttocks by increasing the inner pressure of the specific cells to be higher than the normal pressure.

[0007] However, such a structure increases the number of components, such as a controller, for supplying air to the specific cells when the upper body of the user is raised. This may complicate the structure of the air mat and increases the manufacturing costs.

[0008] In view of the circumstances described above, it is an objective of the present invention to provide an air mat that reduces the likelihood of the buttocks of the user bottoming out when the upper body of the user is raised, while limiting an increase in the number of components.

Means for Solving the Problems

[0009] The means for solving the problems and their advantages are described below.

[0010] To achieve the foregoing objective and in accordance with one aspect of the present invention, an air mat is provided that includes a plurality of cells arranged in a longitudinal direction of the air mat. Each cell is bag-shaped and made of a plastic sheet. Each cell includes an air supply port for supplying air into the cell. The cells include at least one specific cell that corresponds to buttocks of a user and a plurality of non-specific cells other than the specific cell. The air mat further includes a first air supply system and a second air supply system. The first air supply system is connected to the air supply port of the specific cell to supply air to the specific cell. The second air supply system is connected to the air supply ports of the non-specific cells to supply air to the non-specific cells.

[0011] In this structure, of the cells, the first air supply system is connected only to the air supply port of the specific cell corresponding to the buttocks. Consequently, even if a heavy load is applied to the specific cell corresponding to the buttocks when the upper body of the user is raised, the air in the specific cell is unlikely to flow into the non-specific cells corresponding to body parts of the user other than the buttocks. Thus, the structure reduces the likelihood of the buttocks of the user bottoming out when the upper body of the user is raised, without involving a temporary increase in the inner pressure of the specific cell.

[0012] In the above-described air mat, the first air supply system preferably includes a first tube, which is connected to the air supply port of the specific cell, and a first air supply source, which is connected to the first tube. Also, the second air supply system preferably includes a second tube, which is connected to the air supply ports of the non-specific cells, and a second air supply source, which is connected to the second tube.

[0013] As such, the air mat has a simple structure and is inexpensive to manufacture.

[0014] In the above-described air mat, the first air supply source is preferably a first manual pump, and the second air supply source is preferably a second manual pump.

[0015] This simplifies the structure of the air mat as compared to a structure that uses an electric pump as an air supply source.

[0016] In the above-described air mat, the air supply ports of the non-specific cells are preferably aligned in a straight line extending in the longitudinal direction. Also, the air supply ports of the non-specific cells are preferably spaced apart from the air supply port of the specific cell in a width direction of the air mat.

[0017] This facilitates the distinction between the air supply port of the specific cell and the air supply ports of the non-specific cells, allowing the first and second air supply systems to be easily connected to the appropriate air supply ports.

EFFECTS OF THE INVENTION

[0018] The present invention provides an air mat that reduces the likelihood of the buttocks of the user bottoming out when the upper body of the user is raised, while limiting an increase in the number of components.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 

Fig. 1 is a plan view showing a use state of an air mat of one embodiment.

Fig. 2 is a bottom view of the air mat in Fig. 1.

Fig. 3 is a side view showing the air mat in Fig. 1 without the case, tethers, and air supply systems.

Fig. 4 is an enlarged cross-sectional view of a first cell taken along line 4-4 in Fig. 1.

Fig. 5 is an enlarged cross-sectional view of a second cell taken along line 5-5 in Fig. 1.

Fig. 6 is an enlarged cross-sectional view of a third cell taken along line 6-6 in Fig. 1.

Fig. 7 is a partial bottom view of an air mat of a comparison example.

Fig. 8 is a perspective view showing a pressurizer.

Fig. 9 is a schematic diagram showing a test state.

Fig. 10A is a pressure distribution chart showing a test result of an air mat of one embodiment.

Fig. 10B is a diagram showing the sinking amount taken along line 10B-10B in Fig. 10A.

Fig. 10C is a diagram showing the sinking amount taken along line 10C-10C in Fig. 10A.

Fig. 11A is a pressure distribution chart showing a test result of an air mat of a comparison example.

Fig. 11B is a diagram showing the sinking amount taken along line 11B-11B in Fig. 11A.

Fig. 11C is a diagram showing the sinking amount taken along line 11C-11C in Fig. 11A.

MODES FOR CARRYING OUT THE INVENTION

[0020] Referring to the drawings, one embodiment of the present invention is now described in detail. The outline of the structure of an air mat is first described. As shown in Figs. 1 to 3, an air mat 20 includes three types of cells of different structures, first cells 21, second cells 22, and third cells 23. The first to third cells 21, 22 and 23 are arranged in the longitudinal direction of the air mat 20 and accommodated in a case 30. The case 30 is made of a plastic such as polyurethane and has a bottom wall 30a and first to fourth side walls 30b to 30e extending upward from the four sides of the bottom wall 30a. The first side wall 30b and the second side wall 30c are opposite to each other in the longitudinal direction of the air mat 20, and the third side wall 30d and the fourth side wall 30e are opposite to each other in the width direction of the air mat 20. In Fig. 2, a part of the bottom wall 30a is not shown. The cells 21, 22 and 23 are extended in the width direction of the air mat 20 and coupled to the third and fourth side walls 30d and 30e of the case 30.

[0021] On the upper surface of the air mat 20, a pair of tethers 40, which is made of a plastic such as polyurethane, is placed to limit displacement of the cells 21, 22, and 23 while the air mat 20 is used. Each tether 40 extends in the longitudinal direction of the air mat 20 and has two ends each coupled to a corresponding one of the first and second side walls 30b and 30c of the case 30. Further, the outer surface of the bottom wall 30a includes a non-slip portion 50 to limit slipping of the air mat 20 on the bed board, for example, during use. The air mat 20 is used with its upper surface covered by a cover, for example, but the cover is not shown in Fig. 1.

[0022] In the air mat 20, the first cells 21 correspond to the buttocks G including the waist of a user U, the second cells 22 correspond to the shoulders SH and the legs L of the user U, and the third cells 23 correspond to the head H, the back B, and the thighs F of the user U.

[0023] Specifically, the number of the third cells 23 corresponding to the head H is two, the number of the third cells 23 corresponding to the back B is two, and the number of the third cells 23 corresponding to the thighs F is three. The numbers of the second cells 22 corresponding to the shoulders SH and the legs L are two. The number of the first cells 21 corresponding to the buttocks G is two. However, the numbers of cells corresponding to the body parts may be modified as needed.

[0024] The first cells 21 are connected to a first air supply system 60 for supplying air to the first cells 21. The second and third cells 22 and 23 are connected to a second air supply system 70 for supplying air to the second and third cells 22 and 23. The details of the first and second air supply systems 60 and 70 will be described later.

[0025] The cells 21, 22 and 23 are now described in detail.

[0026] As shown in Figs. 1 to 3, each first cell 21 is bag-shaped and made of a plastic sheet, such as a polyurethane sheet. Each first cell 21 includes an air supply port 21a for supplying air into the cell. The section of the first cell 21 facing the third side wall 30d of the case 30 includes a coupling portion 21b such as a button for coupling the first cell 21 to the third side wall 30d. Similarly, the section of the first cell 21 facing the fourth side wall 30e includes a coupling portion (not shown) for coupling the first cell 21 to the fourth side wall 30e.

[0027] As shown in Fig. 4, a partition wall 21c, which extends in the longitudinal and width directions of the air mat 20, is arranged inside each first cell 21. The partition wall 21c is formed of a plastic sheet that is similar to that of the first cell 21. The section of the plastic sheet forming the first cell 21 that is located on the upper side of the partition wall 21c is joined to the partition wall 21c in a plurality of positions, so that the first cell 21 includes a plurality of upper joints 21d. The first cell 21 includes upper bulging sections 21e, which bulge upward, around the upper joints 21d. The upper joints 21d are formed such that two upper joints 21 d are located on each of imaginary straight lines extending parallel to one another in the longitudinal direction of the air mat 20. In other words, the upper joints 21d are arranged on intersection points in a rhombic lattice. Accordingly, the upper bulging sections 21e are also located on imaginary straight lines extending parallel to one another in the longitudinal direction of the air mat 20.

[0028] The section of the plastic sheet forming the first cell 21 that is located on the lower side of the partition wall 21c is joined to the partition wall 21c in a plurality of positions, so that the first cell 21 includes a plurality of lower joints 21f. The first cell 21 includes lower bulging sections 21g, which bulge downward, around the lower joints 21f. In the present embodiment, the lower joints 21f are formed such that two lower joints 21f are located on each of imaginary straight lines extending parallel to one another in the longitudinal direction of the air mat 20. In other words, the lower joints 21f are arranged on intersection points in a rhombic lattice. Accordingly, the lower bulging sections 21g are also located on imaginary straight lines extending parallel to one another in the longitudinal direction of the air mat 20.

[0029] The upper bulging sections 21e and the lower bulging sections 21g communicate with each other through communication ports 21h formed in the partition wall 21c. The upper bulging sections 21e reduce the area of contact with the user U when the air mat 20 is used, giving a soft feel for the user U.

[0030] As shown in Figs. 1 to 3, each second cell 22 is bag-shaped and made of a plastic sheet, such as a polyurethane sheet. Each second cell 22 includes an air supply port 22a for supplying air into the cell. The section of the second cell 22 facing the third side wall 30d of the case 30 includes a coupling portion 22b such as a button for coupling the second cell 22 to the third side wall 30d. Similarly, the section of the second cell 22 facing the fourth side wall 30e includes a coupling portion (not shown) for coupling the second cell 22 to the fourth side wall 30e. The second cells 22 have the same structure as the first cells 21, except that the air supply ports 22a are located on the outer side of the air supply ports 21a of the first cells 21 in the width direction of the air mat 20. As shown in Fig. 5, a partition wall 22c, which extends in the longitudinal and width directions of the air mat 20, is arranged inside each second cell 22. The partition wall 22c is made of a plastic sheet that is similar to that of the second cell 22.

[0031] The section of the plastic sheet forming the second cell 22 that is located on the upper side of the partition wall 22c is joined to the partition wall 22c in a plurality of positions, so that the second cell 22 includes a plurality of upper joints 22d. The second cell 22 includes upper bulging sections 22e, which bulge upward, around the upper joints 22d. The upper joints 22d are formed such that two upper joints 22d are located on each of imaginary straight lines extending parallel to one another in the longitudinal direction of the air mat 20. In other words, the upper joints 22d are arranged on intersection points in a rhombic lattice. Accordingly, the upper bulging sections 22e are also located on imaginary straight lines extending parallel to one another in the longitudinal direction of the air mat 20.

[0032] The section of the plastic sheet forming the second cell 22 that is located on the lower side of the partition wall 22c is joined to the partition wall 22c in a plurality of positions, so that the second cell 22 includes a plurality of lower joints 22f. The second cell 22 includes lower bulging sections 22g, which bulge downward, around the lower joints 22f. In the present embodiment, the lower joints 22f are formed such that two lower joints 22f are located on each of imaginary straight lines extending parallel to one another in the longitudinal direction of the air mat 20. In other words, the lower joints 22f are arranged on intersection points in a rhombic lattice. Accordingly, the lower bulging sections 22g are also located on imaginary straight lines extending parallel to one another in the longitudinal direction of the air mat 20.

[0033] The upper bulging sections 22e and the lower bulging sections 22g communicate with each other through communication ports 22h formed in the partition wall 22c. The upper bulging sections 22e reduce the area of contact with the user U when the air mat 20 is used, giving a soft feel for the user U.

[0034] As shown in Figs. 1 to 3, the third cells 23 differ from the first and second cells 21 and 22 in structure. Each third cell 23 is elongated bag-shaped and made of a plastic sheet, such as a polyurethane sheet. Each third cell 23 includes an air supply port 23a for supplying air into the cell. The positions of the air supply ports 23a in the width direction of the air mat 20 correspond to the positions of the air supply ports 22a of the second cells 22 in the width direction. As shown in Figs. 3 and 6, the section of each third cell 23 facing the third side wall 30d of the case 30 includes coupling portions 23b such as buttons for coupling the third cell 23 to the third side wall 30d. The third cell 23 includes two coupling portions 23b arranged in the vertical direction. Similarly, the section of the third cell 23 facing the fourth side wall 30e of the case 30 includes coupling portions 23c such as buttons for coupling the third cell 23 to the fourth side wall 30e. The third cell 23 includes two coupling portions 23c arranged in the vertical direction. As shown in Fig. 6, unlike the first and second cells 21 and 22, the third cells 23 do not include partition walls. As such, the interior space of each third cell 23 extends in the width direction of the air mat 20 without being partitioned.

[0035] Referring to Figs. 1 and 2, the first air supply system 60 and the second air supply system 70 for supplying air to the air mat 20 are now described.

[0036] The two first cells 21 corresponding to the buttocks G are supplied with air by the first air supply system 60 connected to the respective air supply ports 21a. Specifically, the first air supply system 60 includes a first tube 61, which is connected to the air supply ports 21a of the first cells 21, and a first manual pump 62, which is connected to the first tube 61 to function as a first air supply source. The first tube 61 extends out of the case 30 through the second side wall 30c. The sections of the first tube 61 corresponding to the air supply ports 21a include connection portions 63 for connecting the first tube 61 to the air supply ports 21a. When the first tube 61 is connected, the first cells 21 communicate with each other through the first tube 61 and the air supply ports 21a. The first manual pump 62 is operated to supply air to the first cells 21 through the first tube 61 and the first air supply ports 21a. The operator of the first manual pump 62 operates the first manual pump 62 to supply air to the first cells 21 when the upper body of the user is raised. Then, the operator inserts a hand between the bed board and the air mat 20 to feel and check that the buttocks of the user do not reach the bed board, or bottom out, and then the operator stops supplying air to the first cells 21.

[0037] The two third cells 23 corresponding to the head H, the two second cells 22 corresponding to the shoulders SH, the two third cells 23 corresponding to the back B, the three third cells 23 corresponding to the thighs F, and the two second cells 22 corresponding to the legs L are supplied with air by the second air supply system 70 connected to the respective air supply ports 22a and 23a. Specifically, the second air supply system 70 includes a second tube 71, which is connected to the air supply ports 22a and 23a of the second and third cells 22 and 23, and a second manual pump 72, which is connected to the second tube 71 to function as a second air supply source. The second tube 71 extends out of the case 30 through the second side wall 30c. The sections of the second tube 71 corresponding to the air supply ports 22a and 23a include connection portions 73 for connecting the second tube 71 to the air supply ports. When the second tube 71 is connected, the second and third cells 22 and 23 communicate with one another through the second tube 71 and the air supply ports 22a and 23a. The second manual pump 72 is operated to supply air to the second and third cells 22 and 23 through the second tube 71 and the second and third air supply ports 22a and 23a. The second manual pump 72 supplies air to the second and third cells 22 and 23 in a manner that differs from that of the first manual pump 62. Specifically, instead of checking if the buttocks of the user bottom out, the operator of the second manual pump 72 supplies air until a certain hardness is obtained that gives comfort to the user when lying down, and then the operator stops supplying air to the second and third cells 22 and 23.

[0038] Of the cells forming the air mat 20, the cells corresponding to the buttocks G (the first cells 21) are referred to as specific cells S, and the cells other than the specific cells S (the second and third cells 22 and 23) are referred to as non-specific cells NS. The specific cells S are supplied with air by the first air supply system 60 connected to their air supply ports. The non-specific cells NS are supplied with air by the second air supply system 70 connected to their air supply ports. In the present embodiment, the air supply ports of the non-specific cells NS, namely, the air supply ports 22a and 23a of the second and third cells 22 and 23 corresponding to the head H, shoulders SH, back B, thighs F, and legs L are aligned in a straight line extending in the longitudinal direction of the air mat 20. The air supply ports of the specific cells S, namely, the air supply ports 21a of the two first cells 21 corresponding to the buttocks G, are aligned in a straight line extending in the longitudinal direction of the air mat 20 and spaced apart from the air supply ports 22a and 23a of the second and third cells 22 and 23 in the width direction of the air mat 20. This facilitates the distinction between the air supply ports of the specific cells S (the first cells 21) and the air supply ports of the non-specific cells NS (the second and third cells 22 and 23), allowing the first and second air supply systems 60 and 70 (the first and second tubes 61 and 71) to be easily connected to the appropriate air supply ports when assembling the air mat 20.

[0039] The operation of the air mat 20 is now described by comparing it with a comparison example.

[0040] The structure of an air mat 120 of a comparison example is first described.

[0041] As shown in Fig. 7, the air mat 120 of the comparison example differs from the air mat 20 of the present embodiment in that the air mat 120 includes second cells 22, instead of first cells 21, as the specific cells S corresponding to the buttocks G, and that all second and third cells 22 and 23 forming the air mat 120 are connected to a first air supply system 160. That is, the air mat 120 includes a plurality of second cells 22 corresponding to the shoulders SH, the buttocks G, and the legs L of the user U and a plurality of third cells 23 corresponding to the head H, the back B, and the thighs F of the user U. The number of the third cells 23 corresponding to the head H is two, the number of the third cells 23 corresponding to the back B is two, and the number of the third cells 23 corresponding to the thighs F is three. The numbers of the second cells 22 corresponding to the shoulders SH, the buttocks G, and the legs L are two. In the air mat 120 of the comparison example, same reference numerals are given to those components that are the same as the corresponding components of the present embodiment. Such components will not be described in detail.

[0042] The air supply ports of all the cells forming the air mat 120, namely, the air supply ports 22a and 23a of the second and third cells 22 and 23, are aligned in a straight line extending in the longitudinal direction of the air mat 120 and connected to the first air supply system 160. Specifically, the first air supply system 160 includes a first tube 161, which is connected to the air supply ports 22a and 23a of the second and third cells 22 and 23, and a first manual pump 162, which is connected to the first tube 161. The first tube 161 extends out of the case 30 through the second side wall 30c. The sections of the first tube 161 corresponding to the air supply ports 22a and 23a include connection portions 163 for connecting the first tube 161 to the air supply ports. When the first tube 161 is connected, the second and third cells 22 and 23 communicate with one another through the first tube 161 and the air supply ports 22a and 23a.

[0043] A comparative test between the air mat 20 of the present embodiment and the air mat 120 of the comparison example was performed using a pressurizer in accordance with JIS T9256-3 "Pressure distribution mattress for home use". Specifically, as shown in Fig. 8, a weight W was placed on a pressurizer P so that the pressurizer P and the weight W together weigh 23 kg. As shown in Fig. 9, for each of the air mats 20 and 120, a contact pressure sensor CS is placed on the two specific cells S corresponding to the buttocks G, and the pressurizer P was placed on the contact pressure sensor CS. The distribution of the pressure applied to the specific cells S and the sinking amount of the specific cells S were measured for each of the air mats 20 and 120. The contact pressure sensor CS was connected to a computer (PC) to obtain the test data. Figs. 10A to 10C and Figs. 11A to 11C show the results of the comparative test. Figs. 10A and 11A each show the distribution of pressure, and the unit of the numbers in these figures is kPa. In each of Figs. 10A and 11A, the x-axis corresponds to the width direction of the air mat, and the y-axis corresponds to the longitudinal direction of the air mat. Figs. 10B, 10C, 11B, and 11C show the sinking amounts of the specific cells S. The sinking amounts increase in the directions of the arrows.

[0044] Fig. 10A shows that the specific cells S (the two first cells 21) of the air mat 20 of the present embodiment evenly support the pressurizer P and are free of partial compressions. Figs. 10B and 10C show that the sinking of the specific cells S is shallow and substantially uniform. In contrast, Fig. 11A shows that the specific cells S of the air mat 120 of the comparison example (the two second cells 22) include partial compressions by the pressurizer P. Figs. 11B and 11C show that the specific cells S include sections that sink deeply, corresponding to the partial compressions. The maximum contact pressure of the specific cells S of the air mat 20 of the present embodiment (the two first cells 21) was 6.3 kPa (47 mmHg), whereas the maximum contact pressure of the specific cells S of the air mat 120 of the comparison example (the two second cells 22) was 13.6 kPa (102 mmHg). The air mat 20 of the present embodiment reduces the likelihood that the buttocks G of the user U bottom out as compared to the air mat 120 of the comparison example.

[0045] The air mat 20 of the present embodiment evenly supports the pressurizer P and allows the sinking to be shallow as compared to the air mat 120 of the comparison example for the following reasons.

[0046] That is, the air supply ports 22a and 23a of all the second and third cells 22 and 23 forming the air mat 120 of the comparison example are connected to the first tube 161 of the first air supply system 160. When the pressurizer P is placed on the two second cells 22 corresponding to the buttocks G (the specific cells S), the air within the second cells 22 (the specific cells S) flows out of the second cells 22 through the air supply ports 22a. The air flowing out of the specific cells S (the two second cells 22) enters the non-specific cells NS (the second and third cells 22 and 23) through the first tube 161. This reduces the inner pressure of the specific cells S (the two second cells 22), so that the specific cells S (the two second cells 22) fail to evenly support the pressurizer with their entire sections, causing the specific cells S (the two second cells 22) to partially sink deeply.

[0047] In the air mat 20 of the present embodiment, the air supply ports 21a of the first cells 21 corresponding to the buttocks G (the specific cells S) are connected to the first tube 61 of the first air supply system 60, and the air supply ports 22a and 23a of the second and third cells 22 and 23 (the non-specific cells NS) are connected to the second tube 71 of the second air supply system 70. When the pressurizer P is placed on the two first cells 21 (the specific cells S), the air within the first cells 21 (the specific cells S) acts to flow out of the first cells 21 through the air supply ports 21a. However, the first tube 61 connected to the air supply ports 21a of the first cells 21 (the specific cells S) is connected only to the air supply ports 21a of the first cells 21. As such, of the first to third cells 21, 22 and 23 forming the air mat 20, the first cells 21 (the specific cells S) are independent of the other cells in terms of the air supply systems, so that, unlike the air mat 120 of the comparison example, the air in the specific cells S (the first cells 21) will not flow out into the non-specific cells NS (the second and third cells 22 and 23). This maintains the inner pressure of the first cells 21 (the specific cells S) allowing the entire sections of the first cells 21 to evenly support the pressurizer P. The specific cells S (the first cells 21) are therefore unlikely to sink deeply.

[0048] The present embodiment achieves the following advantages.

(1) The air mat 20 includes the first air supply system 60 and the second air supply system 70. Of the cells forming the air mat 20, the first air supply system 60 is connected to the air supply ports 21a of the first cells 21 corresponding to the buttocks G of the user U (the specific cells S) to supply air into the first cells 21. Of the cells forming the air mat 20, the second air supply system 70 is connected to the air supply ports 22a and 23a of the second and third cells 22 and 23 (the non-specific cells NS) other than the first cells 21 corresponding to the buttocks G (the specific cells S) to supply air into the second and third cells 22 and 23.
Consequently, even if a heavy load is applied to the specific cells S corresponding to the buttocks G (the first cells 21) when the upper body of the user U is raised, the air in the specific cells S will not flow into the non-specific cells NS (the second and third cells 22 and 23). This maintains the inner pressure of the specific cells S (the first cells 21) when the upper body of the user U is raised. Thus, the likelihood that the buttocks G will bottom out when the upper body of the user U is raised is reduced without the need for temporarily increasing the inner pressure of the specific cells S (the first cells 21).

(2) The first air supply system 60 includes the first tube 61, which is connected to the air supply ports 21a of the first cells 21 (the specific cells S), and the first manual pump 62, which is connected to the first tube 61 to function as the first air supply source. The second air supply system 70 includes the second tube 71, which is connected to the air supply ports 22a and 23a of the second and third cells 22 and 23 (the non-specific cells NS), and the second manual pump 72, which is connected to the second tube 71 to function as the second air supply source.
As such, the air mat has a simple structure and is inexpensive to manufacture. The first and second manual pumps 62 and 72 are used as the first and second air supply sources. This simplifies the structure of the air mat as compared to a structure that uses electric pumps as the air supply sources.

(3) In the air mat 20, the air supply ports 22a and 23a of the second and third cells 22 and 23 (the non-specific cells NS) are aligned in a straight line extending in the longitudinal direction. The air supply ports 22a and 23a of the second and third cells 22 and 23 (the non-specific cells NS) are spaced apart from the air supply ports 21a of the first cells 21 (the specific cells S) in the width direction of the air mat 20.

[0049] This facilitates the distinction between the air supply ports of the specific cells S (the first cells 21) and the air supply ports of the non-specific cells NS (the second and third cells 22 and 23) allowing the first and second air supply systems 60 and 70 to be easily connected to the appropriate air supply ports.

[0050] The above-described embodiment may be modified as follows, for example.

[0051] The cells corresponding to the buttocks G of the user U are not limited to a plurality of first cells 21. A single cell that is large enough to accommodate the buttocks G may serve as the cell corresponding to the buttocks G.

[0052] The air supply ports of the non-specific cells NS do not have to be aligned in a straight line extending in the longitudinal direction of the air mat. The air supply ports of the non-specific cells NS do not have to be spaced apart from the air supply ports of the specific cells S in the width direction of the air mat.

[0053] The cells forming the air mat are not limited to the first to third cells 21, 22 and 23. That is, the air mat may be formed by cells of any shapes.

[0054] The first and second air supply sources are not limited to the first and second manual pumps. First and second electric pumps may be used as the first and second air supply sources. In this case, the first air supply system including the first electric pump is still connected only to the specific cells corresponding to the buttocks G, and it is therefore unnecessary to supply air to the specific cells when the upper body of the user is raised. This eliminates the need for a controller or other devices for supplying air to the specific cells when the upper body of the user is raised. Thus, as compared to a conventional air mat that supplies air to the specific cells when the upper body of the user is raised, the air mat described above limits the likelihood that the buttocks of the user will bottom out when the upper body of the user is raised, while limiting an increase in the number of components.

DESCRIPTION OF THE REFERENCE NUMERALS

[0055] 20: Air Mat, 21: First Cell, 22: Second Cell, 23: Third Cell, 21a: Air Supply Port, 22a: Air Supply Port, 23a: Air Supply Port, 60: First Air Supply System, 61: First Tube, 62: First Manual Pump, 70: Second Air Supply System, 71: Second Tube, 72: Second Manual Pump, S: Specific Cell, NS: Non-Specific Cell

Claims

1. An air mat comprising:

a plurality of cells arranged in a longitudinal direction of the air mat, wherein

each cell is bag-shaped and made of a plastic sheet, and

each cell includes an air supply port for supplying air into the cell,

the air mat being characterized in that

the cells include at least one specific cell that corresponds to buttocks of a user and a plurality of non-specific cells other than the specific cell, and

the air mat further comprises:

a first air supply system that is connected to the air supply port of the specific cell to supply air to the specific cell; and

a second air supply system that is connected to the air supply ports of the non-specific cells to supply air to the non-specific cells.

2. The air mat according to claim 1, characterized in that
the first air supply system includes a first tube, which is connected to the air supply port of the specific cell, and a first air supply source, which is connected to the first tube, and
the second air supply system includes a second tube, which is connected to the air supply ports of the non-specific cells, and a second air supply source, which is connected to the second tube.

3. The air mat according to claim 2, characterized in that
the first air supply source is a first manual pump, and
the second air supply source is a second manual pump.

4. The air mat according to any one of claims 1 to 3, characterized in that
the air supply ports of the non-specific cells are aligned in a straight line extending in the longitudinal direction, and
the air supply ports of the non-specific cells are spaced apart from the air supply port of the specific cell in a width direction of the air mat.

Drawing