Bathtub

Abstract

To reduce a bather's sense of fear and anxiety felt when assuming a supine posture and prevent the bather from having a sense of instability when sitting up.SOLUTION: A bathtub includes a backrest part 1 for receiving and supporting the back of a bather, a seat part 2 for receiving and supporting the buttocks, a calf support part 3 for receiving and supporting the back of the knees, and a footrest part 4, the deepest part of the bathtub. The calf support part 3 is comprised of a rear downward sloping surface 14 for supporting an area of the thigh near the knee behind the bent knee of the bather, a front downward sloping surface 15 for supporting an area of the calf near the knee, and a rising surface 16 connecting to the footrest 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bathtub. More specifically, the present invention relates to a bathtub in which a person takes a bath while reclining. [Background technology]

[0002] Conventionally, bathtubs in which bathers bathe in a reclining position include those that have a steeply inclined backrest on part of the inner wall of the bathtub and a seat that is one step higher than the bottom of the bathtub, giving the bather the sensation of lying on their back (lying down) as if they were sitting on a chaise lounge (see Patent Document 1).

[0003] Specifically, this bathtub has a backrest surface formed by an inclined surface set within an angle range of 110° to 150° with respect to the bottom wall surface (in other words, the horizontal plane), a seating surface portion that slopes diagonally upward from the lower edge of the backrest surface toward the front of the bathtub at an angle range of 10° to 20° with respect to the horizontal plane, and a bathtub bottom portion in which a step is formed at the tip edge of the seating surface opposite the backrest surface so that it slopes down almost vertically toward the bottom wall surface and accommodates the lower legs when the knees are bent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-61502 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, with this bathtub, when sitting on the seat to lie down, the upward slope creates the sensation of falling backwards, which can cause feelings of fear and anxiety.

[0006] Furthermore, when sitting on a seat that slopes upward and assuming a lying down position, the lower part of the thigh, i.e., the part closest to the knee, is not supported by the seat, and the heel of the lower leg, which bends at the knee joint, touches the bottom of the bathtub. This causes body pressure to concentrate on the thighs and heels, which are supported near the edge of the seat, and the body pressure is not distributed sufficiently, making it impossible to relax while bathing.

[0007] To provide a bathtub in which a person can take a bath in a reclining position, reducing the sense of fear or anxiety when lying down and causing no sense of instability when standing up. [Means for solving the problem]

[0008] In order to achieve this objective, the bathtub described in claim 1 comprises a backrest section that supports the bather's back, a seat section that supports the buttocks, a calf support section that supports the backs of the knees, and a footrest section that constitutes the deepest part of the bathtub, and the calf support section is composed of a rear downward sloping surface that supports the part of the bather's thigh closest to the knees, a front downward sloping surface that supports the part of the calf closest to the knees, and a rising surface that connects to the footrest.

[0009] In addition, in the bathtub described in claim 1, it is preferable that the height difference between the calf support section and the footrest is such that when the buttocks are placed in the seat, both legs are stretched out naturally, and both heels are placed on the footrest, the calf support section lightly supports the backs of both knees, allowing the bather to assume a relaxed bathing posture.

[0010] Furthermore, the bathtub of the present invention comprises a backrest section that supports the bather's back, a seat section that supports the buttocks, a calf support section that supports the backs of the knees, and a footrest section that is the deepest part of the bathtub, and the calf support section is composed of a rear downward inclined surface that supports the part of the thigh behind the bent knee of the bather close to the knee, a front downward inclined surface that supports the part of the calf close to the knee, and a rising surface that is connected to the footrest, and the backrest angle θ1 of the backrest section with respect to the horizontal plane of the backrest surface is set to 135° or less, while the seat surface angle θ3 of the seat section with respect to the horizontal plane of the seat surface is set to 135° or less. the angle θ2 between the seat surface and the backrest surface is set to 121° to less than 130°; the angle θ4 between the front downward sloping surface and the rear downward sloping surface of the calf support part is set to 125° to 153°; the height difference between the boundary between the front downward sloping surface and the rear downward sloping surface of the calf support part and the floor surface of the footrest area is set to 180 to 190 mm; and the height difference between the boundary between the front downward sloping surface and the rising surface of the calf support part and the footrest area is set to 130 mm to 140 mm. Effect of the Invention

[0011] The bathtub described in claim 1 is equipped with a calf support section that is inclined forward and has a downwardly inclined front surface that forms a receiving shape, so that the bather does not feel like falling backward when sitting down. Moreover, the bather can sit down and shift backward on the seat until he reaches the backrest (moving the upper body toward the backrest), and then tilt his upper body backward to assume a lying position, so that he can lie down without anxiety. In other words, it is possible to eliminate the fear or anxiety felt when lying down.

[0012] In addition, with this bathtub, the calf support section supports the backs of the knees and distributes body pressure, distributing the weight of the lower legs and reducing the weight on the feet by half, allowing you to bathe in a relaxed position. [Brief description of the drawings]

[0013] [Figure 1]1 is a perspective view showing one embodiment of a bathtub according to the present invention. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a CC vertical cross-sectional view of the bathtub. [Figure 4] FIG. 2 is a cross-sectional view of the bathtub taken along line AA. [Diagram 5] FIG. 4 is a cross-sectional view taken along line BB of the bathtub. [Figure 6] FIG. 2 is an explanatory diagram of the posture of a bather just before sitting in the bathtub. [Figure 7] FIG. 2 is an explanatory diagram of the posture of a bather sitting in the bathtub. [Figure 8] 1 is an explanatory diagram of the bather's posture when the bather moves to a fixed position on the seat in the bathtub. FIG. [Figure 9] FIG. 2 is an explanatory diagram of the state in which the bathtub is reclined in the bath. [Figure 10] 1 is a graph showing the relationship between the angle between the seat and the backrest when used as a chaise lounge and the rate at which the user feels uncomfortable. [Figure 11] FIG. 13 shows another embodiment of a bathtub according to the present invention, in which (A) is a plan view and (B) is a vertical cross-sectional view taken along line AA. [Figure 12] FIG. 2 is an explanatory diagram of the state in which a person is in a reclining position in the bathtub of the first embodiment of the present invention. [Figure 13] FIG. 1 is an explanatory diagram of a state in which a person is lying down in a bathtub in the related art (Comparative Example 1). [Figure 14] FIG. 13 is an explanatory diagram of a state in which a person is lying down in a bathtub in the related art (Comparative Example 2). [Figure 15] FIG. 1 shows pressure distribution diagrams when taking a lying-down position in the bathtub of Example 1, where (A) shows the measurement results at the heels, (B) shows the measurement results at the calf support area, and (C) shows the measurement results at the seat. [Figure 16] FIG. 13 is a pressure distribution diagram when a person takes a lying-down position in the bathtub of Comparative Example 1, where (A) shows the measurement results at the heels and (B) shows the measurement results at the seat. [Figure 17] FIG. 11 is a pressure distribution diagram when taking a lying-down position in the bathtub of Comparative Example 2, where (A) shows the measurement results at the heels and (B) shows the measurement results at the seat. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The configuration of the present invention will be described in detail below based on the embodiment shown in the drawings. In this specification, unless otherwise specified, the front-rear direction refers to the longitudinal direction of the bathtub, the left-right direction refers to the lateral direction of the bathtub, i.e., the width direction, and the up-down direction refers to the height direction of the bathtub. The rear refers to the side where the backrest is formed, and the front refers to the side where the footrest is formed on the opposite side of the backrest.

[0015] Figures 1 to 5 show one embodiment of the bathtub of the present invention. This bathtub comprises a backrest section 1, a seat section 2, a calf support section 3, a footrest section 4, armrest sections 5, and a pillow section 6. In the case of the bathtub of this embodiment, as one example only, it is integrally molded by vacuum forming an acrylic resin plate. Of course, it goes without saying that the bathtub may be molded by other molding methods.

[0016] The backrest portion 1 is intended to support the back of a bather in a reclining position, and is formed by making the inner wall surface at the rear of the bathtub (called the rear side portion 13) an inclined surface that is inclined at an appropriate angle θ1 with respect to the horizontal plane.

[0017] The inclination angle of the backrest 1 (the angle of the backrest surface in this specification, referred to as the backrest angle) is more effective from the viewpoint of providing a relaxation effect by adopting a reclining bath posture. However, on the other hand, if the inclination angle is too large (if the bather reclins too much), it becomes difficult for the bather to get up, and the bather may feel more uncomfortable, such as fear or anxiety, when leaning back the upper body. Specifically, according to the results of an experiment shown in FIG. 10, which seeks the relationship between the angle formed by the seat and backrest of a chaise lounge and the sense of stability given to the user, some people start to feel uncomfortable when the backrest angle with respect to the seat is 130°, and the number of people who feel uncomfortable increases sharply when the angle exceeds 130° and is between 150° and 155°, or 175°. According to the results of this experiment, it can be said that the angle θ2 between the seat 2 and the backrest 1 (referred to as the backrest angle) is preferably less than 130°. Furthermore, the greater the backrest angle θ1 relative to the horizontal plane, the greater the relaxation effect, but the more difficult it becomes for the bather to get up, and specifically, if the angle exceeds 135° relative to the horizontal plane, it becomes difficult to get up even using the handrail section 7. In other words, the inclination angle of the backrest section 1 is not limited to a specific angle, but as an example, the backrest angle θ1 is set to 135° or less, and the backrest angle θ2 is set to less than 130°, and it is preferable to select the maximum angle possible within that range.

[0018] The seat 2 is located between the footrest 4 and the backrest 1, one step higher than the footrest 4, and supports the bather's buttocks without slipping, allowing the bather to take a bath in a relaxed semi-supine position. Therefore, it is preferable that the seat 2 is formed with a seat angle θ3 that can at least prevent the buttocks from slipping forward, that is, a slope that slopes upward toward the front of the bathtub (i.e., toward the footrest 4). This stabilizes the position of the lower body, including the buttocks, and stabilizes the lying-down bathing position. On the other hand, if the seat angle θ3 is too large, and the backrest angle θ1 is set within an angle range where the bather does not start to feel fear or anxiety when leaning back the upper body, the back-seat angle θ2 becomes narrow and a feeling of crampedness occurs. Therefore, the seat angle θ3 is an angle that can suppress forward sliding of the buttocks while preventing the seat-back angle θ2 from becoming narrow and causing a feeling of crampedness; specifically, although it is not limited to a specific value, for example, as just one example, it should be an upward incline toward the front of 4° to 14°, preferably 6° to 10°, more preferably 7° to 9°, and most preferably 9°.

[0019] Therefore, in this embodiment, the seat surface of the seat part 2 is set at a seat surface angle θ3 of 9° so that the seat surface is inclined upward from the lower end edge of the backrest part 1 toward the front of the bathtub, and the backrest angle θ2 is set to be less than 130°, while the backrest angle θ1 is set to 135°, so that the bather can relax without feeling discomfort or anxiety when leaning back the upper body. That is, in the case of this embodiment, the backrest angle θ1 is formed so as not to exceed 135°, while the backrest angle θ2 is formed at 126°, which is less than 130°. In other words, the backrest angle θ1 is selected as the maximum angle possible within the range of 135° or less, and the backrest angle θ2 is set to be less than 130°, and when the backrest angle θ2 is selected within the range of 4° to 14° and the maximum possible backrest angle θ2 is selected, it is preferable that it is less than 121° to 130°.

[0020] Furthermore, a calf support section 3 is provided between the foot rest section 4 and the seat section 2 to support the back of the knee. The calf support section 3 is provided in front of the seat section 2 to support the back of the knee of the bather, and has a rear downward inclined surface 14 that supports the lower part of the thigh, i.e., the part close to the knee, a front downward inclined surface 15 that supports the upper part of the calf, i.e., the part close to the knee, and a rising surface 16 that is steeper than the front downward inclined surface 15 and connects to the foot rest area 4. In the case of this embodiment, the calf support section 3 is formed integrally with the seat section 2. That is, by forming the seat section 2 to a length up to the back of the knee position that supports not only the upper part of the thigh but also the lower part of the thigh, the rear downward inclined surface 14 of the calf support section 3 is formed at the tip part of the seat section 2, and the front downward inclined surface 15 and the rising surface 16 are continuously formed from the topmost part of the seat section (i.e., the tip part of the rear downward inclined surface 14) toward the foot rest area 4. The tip portion of the rear downward inclined surface 14 of the calf support portion 3 (that is, the boundary portion between the front downward inclined surface 15 and the rear downward inclined surface 14 ) becomes the topmost portion of the seat portion 2 .

[0021] Here, the angle θ4 between the rear downward inclined surface (in other words, the seat surface) 14 and the front downward inclined surface 15 of the calf support part 3 (in other words, the angle of the top part of the seat) is preferably an angle and shape that forms a shape along the back of the knee of a bather who takes a neutral posture. As a result, the upper part of the calf near the knee is supported, the weight of the lower leg is distributed and the weight on the foot is halved, making bathing more comfortable than in a conventional bathtub. The inventors created models with various angles and conducted experiments on the degree of relaxation by test subjects of various physiques, and found that a suitable sense of relaxation can be obtained at 125° to 153°, preferably 138° to 150°, more preferably 141° to 148°, and even more preferably 145° to 148°, and the optimal angle is around 148°. Therefore, in the case of this embodiment, for example, as a mere example, the angle θ4 of the top part of the seat is set to 148°.

[0022] In this embodiment, the rear downward inclined surface 14 is configured to have the same inclination angle as the seat surface of the seat part 2, but this is not particularly limited, and a different inclination angle may be used as necessary, and in some cases, a boundary may be formed between the seat surface of the seat part 2. Of course, the calf support part 3 and the seat part 2 are not limited to being continuously and integrally formed, and in some cases, they may be formed separately and connected as necessary.

[0023] The foot rest 4 is formed at the front of the bathtub, and is the deepest part of the bathtub. In other words, the foot rest 4 is one step lower than the seat 2, and is formed continuously with the lower edge of the rising surface 16 of the calf support part 3. In this embodiment, the foot rest 4 has a floor surface 10 with a slight downward slope, for example, a drainage slope of 1.5°, so that hot water gathers from all directions toward an arbitrary position, for example, the central drain 9, which is the lowest position of the bathtub. At the same time, the foot rest 4 is continuous with the lower ends of the left and right side parts 11 and the front side part 12, and the rising surface 16. It goes without saying that the parts that come into contact with the bather in the bathtub, especially the parts that may be pressed hard against them, are appropriately curved to eliminate corners. The drain 9 is equipped with a drainage device 17 so that the hot water in the bathtub can be drained.

[0024] Here, the height difference (step) between the calf support part 3 and the floor surface 10 of the footrest 4 is not limited to a specific value, but it is preferable that when the buttocks are placed in the seat 2, both legs are naturally stretched, and both heels are placed on the footrest 4, the calf support part 3 lightly supports the backs of both knees, allowing a relaxed bathing posture. If the height difference is too large (i.e. too deep), the weight on the calf support part 3 increases, and if it is too small (i.e. too shallow), the weight on the heels increases, making it difficult to assume a relaxed bathing posture. Specifically, as merely one example, it is preferable that the height difference (step) between the boundary between the front downward inclined surface 15 and the rear downward inclined surface 14 of the calf support section 3 (in other words, the top of the seat section 2) and the floor surface 10 of the footrest area 4 be approximately 180 to 190 mm, and the height difference (step) between the boundary between the front downward inclined surface 15 and the rising surface 16 of the calf support section 3 and the footrest area 4 be approximately 130 to 140 mm.

[0025] Due to the height difference (step) between this calf support section 3 and the floor surface 10 of the footrest 4, the bather takes up a bathing posture at an angle approximating a neutral posture, and the bather's feet (heels) touch the floor surface 10 of the footrest 4, giving the bather the sensation of lying on his / her back while achieving a sense of stability in the lying bathing position regardless of the presence of buoyancy.

[0026] Meanwhile, armrests 5 on which the bather's arms are placed are formed on both the left and right side surfaces 11 of the bathtub. These armrests 5 are preferably formed at a position and shape where the bather can place their arms when lying down, for example, at an inclination angle that makes them approximately parallel to the seat from a position close to the backrest 1 to a position where the bather can easily place their hands while lying down when getting up. In this embodiment, for example, they are integrally molded as shelf-like protrusions about 80 mm wide protruding from both the left and right side surfaces 11.

[0027] In addition, water pools on the seat surface because the seat surface of the seat 2 is inclined toward the back, i.e., toward the backrest 1. Therefore, drain grooves 8 with a downward slope (sloping downward toward the footrest 4) are formed in the boundaries between the armrests 5 and the seat 2 on the left and right side sections 11 of the bathtub, respectively, so that hot and cold water drains naturally into the footrest 4 without remaining on the seat 2. It is preferable that the drain grooves 8 have a slope of about 2° to 3° downward from the horizontal plane, for example.

[0028] The pillow section 6 is not limited to a specific material or structure, but in the present embodiment, for example, it is formed integrally with the bathtub, and is composed of a pillow frame 20 with a triangular cross section that is continuous with the upper end of the backrest section 1 and protrudes above the edge of the bathtub, and an elastic pillow member 21 made of polyurethane foam or the like that is covered from above. The front surface of the pillow frame 20 of the pillow section 6 is provided with an inclination angle θ5 of, for example, about 15° so as to be slightly raised forward relative to the backrest section 1, so that the bather's head is slightly tilted forward while bathing. This allows the head to be in a natural posture without feeling as if it is arching back. Here, it goes without saying that the provision of the pillow section 6 and the pillow section 6 to tilt the bather's head slightly forward are not essential components of the present invention. The pillow section 6 is not particularly limited to the above-mentioned one, and it goes without saying that a pillow member as a separate part consisting of a cylindrical elastic pillow member made of polyurethane foam or the like and a support shaft and a bearing part that penetrate and support the elastic pillow member may be adopted, although not shown.

[0029] The handrail section 7 is arranged so as to occupy the area between the position where the bather can place his / her hands when sitting on the front downward sloping surface 15 of the calf support section 3 and the position where the bather can place his / her hands when leaning against the backrest section 1. For example, in a bathtub with a total length of about 1795 mm (inner dimension 1549 mm), a straight bar (grip bar) with a length of about 500 mm is used as the handrail section 7, and is arranged and fixed on both the left and right side surfaces 11 of the bathtub so as to straddle the space between the footrest section 4 and the seat section 2.

[0030] In addition, although not shown in the figure, faucets for supplying hot water into the bathtub or piping for reheating the water, such as a circulation adapter, are connected at appropriate positions to this bathtub so that temperature-adjusted hot water flows in and is stored to an appropriate depth.

[0031] It is preferable that the front wall surface (front side surface portion 12) and both left and right side wall surfaces (left and right side surface portions 11) of the bathtub be as close to vertical as possible while ensuring a draft angle sufficient to allow the bathtub to be removed from the manufacturing mold, in order to expand the space inside the bathtub and prevent it from feeling cramped. As merely one example, it is preferable that the inclination angle of the front side surface of the bathtub is set to 10° with respect to the vertical plane, the inclination angle of the left and right side surfaces is set to 5°, and the inclination angle of the rising surface 16 is set to 15°. The bathtub is also supported by legs 18 whose height can be finely adjusted as necessary.

[0032] In the case of a bathtub constructed as described above, a comfortable bathing experience can be achieved as follows.

[0033] First, when taking a bath, a person stands on the floor surface 10 of the footrest 4 at the front of the bathtub (as shown in FIG. 6), places his / her hands on the bathtub flange 22 or the handrail 7, and slowly lowers his / her hips onto the front downward inclined surface 15 of the calf support part 3 (in other words, the forward inclined portion of the seating surface), and sits down (as shown in FIG. 7). At this time, since the front downward inclined surface 15 is inclined forward, the bather does not feel as if he / she is falling backwards.

[0034] Furthermore, while placing hands on the handrail 7 or bathtub flange 22, the upper half of the body can be lowered backward toward the backrest 1, either by sliding over the rear downward inclined surface 14 of the calf support part 3 and the seat surface of the seat part 2 or along the seat surface (state of Fig. 7 to Fig. 8). In this case, too, the upper half of the body can be slid over the seat surface while still placing hands on the handrail 7, until the buttocks are placed in the innermost part of the seat part 2, and then the back can be rested against the backrest 1 (state of Fig. 9). The bather places the buttocks in the innermost part of the seat surface and rests against the backrest 1, eliminating the anxiety of falling backward.

[0035] Meanwhile, the thighs of the bather are supported by the seat 2, while the upper calves of the lower legs are supported by the front downward sloping surface 15 of the calf support section 3. Therefore, the knee joints of the lower legs are naturally bent by their own weight, and the legs hang down on the footrest 4 with the heels touching the floor surface 10 (as shown in FIG. 9). This allows the bather to naturally lie down and adopt a bathing posture that is close to a neutral posture. Moreover, by bending the knees and sinking the legs into the footrest 4, the body does not float, and the feeling of instability in the lying down bathing position can be suppressed. This provides the sensation of lying on one's back (feeling of lying down) while maintaining a stable lying down bathing position.

[0036] Next, when getting out of the bathtub, the user can do so safely and easily by following the reverse procedure to that used when bathing. First, the bather places his / her hands on the armrests 5 or handrails 7 and raises his / her upper body from the lying-down bathing position shown in Fig. 9 (as shown in Fig. 8). After that, the bather grasps the handrails 7 and slides his / her body to the front of the seat 2, and moves his / her upper body onto the front downward inclined surface 15 of the calf support part 3 (in other words, the front inclined part of the seat) (as shown in Fig. 7). Then, the bather slowly stands up (as shown in Fig. 6). At this time, the feet are pulled directly below the front downward inclined surface 15 of the calf support part 3, i.e., to the lower edge of the rising surface 16, and are retracted in front of the knees (as shown in Fig. 7), making it easy to stand up.

[0037] The above-mentioned embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto and can be modified in various ways without departing from the scope of the present invention. For example, in the above-mentioned embodiment, the seat surface of the seat 2 is sloped downward from the foot side to the buttocks side in order to support the buttocks of the bather without slipping and to enable bathing in a relaxed semi-supine position. However, it is considered that some bathers may not be able to fully retract their feet or calves when standing up, making it difficult for them to stand up. Therefore, as shown in FIG. 11, for example, the width of the drain groove 8 of the rising surface 16 connecting the foot rest 4 and the seat 2 (i.e., the width from the drop-off portion of the drain groove 8 into the foot rest 4 to the floor surface 10 of the foot rest 4) may be widened, or the depth of the drain groove 8 of the rising surface 16 may be deepened to provide a space 19 in which the calf and heel parts of the bather can be retracted when standing up. By forming this space 19, the bather can retract the position of the feet behind the position of the knees when standing up, allowing the bather to assume a posture that makes it easier to stand up. EXAMPLES

[0038] The bathtub shown in Fig. 12 was formed by processing an acrylic sheet for bathtubs, Acrylite PX200 (registered trademark), manufactured by Mitsubishi Chemical Corporation, by vacuum forming. Here, the bathtub is 1795 mm long x 950 mm wide x 520 mm deep, and includes a backrest section 1, a seat section 2, a calf support section 3, a footrest section 4, an armrest section 5, and a pillow section 6. The backrest angle θ1 of the backrest section 1 is 135°, the seat angle θ3 of the seat section 2 is 9°, and the back and seat angle θ2 is 126°. Furthermore, the angle θ4 between the rear downward inclined surface (in other words, the seat surface) 14 and the front downward inclined surface 15 of the calf support section 3 (in other words, the angle of the topmost part of the seat) is set to 148°. The height from the floor surface 10 of the footrest 4 to the top of the seat 2 was 189 mm, and the height difference (step) to the front edge of the front downward inclined surface 15 of the calf support section 3 (the boundary between the front downward inclined surface 15 and the rising surface 16) was 135 mm. A straight rod 500 mm long was attached as the handrail section 7 at a depth of about 80 mm from the edge of the bathtub, so as to be positioned in the front-to-rear direction with the top of the seat 2 (near the boundary between the front downward inclined surface 15 and the rear downward inclined surface 14 of the calf support section 3) as the center. The length of the front downward inclined surface 15 in a plan view was about 150 mm. Comparative Example 1

[0039] For comparison, a bathtub was created as shown in Fig. 13, which is equipped with a backrest, a seat 2, and a footrest. This bathtub is structurally different from the bathtub in Example 1 in that it does not have a calf support section 3, and the angles between the upward slope of the seat 2 and the backrest are also set at 9° and 126°, respectively, but the length from the bottom edge of the backrest to the front edge of the seat 2, i.e., the depth of the seat 2, is 305mm. In this bathtub, the bather's back, buttocks, and heels are supported by contacting the backrest, seat 2, and footrest. Comparative Example 2

[0040] For comparison, a conventional bathtub without a seat 2 and a large backrest was also created (see Figure 14). In this bathtub, the bottom of the bathtub directly supports the bather's buttocks and legs, and the side of the bathtub is used as a backrest. The bathtub itself is 1900 x 1100 x 545 mm, and has a capacity of 470 liters. In this bathtub, the bather's buttocks, calves, and heels are mainly supported by the backrest and bottom of the bathtub.

[0041] Comparing the bathtub of Example 1 of the present invention, which is constructed as described above, with the bathtubs of Comparative Examples 1 and 2, it was confirmed that the bathtub of Example 1 of the present invention has clearly fewer areas where body pressure concentrates than the bathtubs of Comparative Examples 1 and 2, and is more relaxing.

[0042] That is, the pressure distribution in the heel area (area indicated by the symbol X) shows that the bathtubs of Comparative Examples 1 and 2 both have areas of strong pressure (areas shown darkly) (see Figures 16(A) and 17(A)), whereas the bathtub of Example 1 does not show any areas of strong pressure (see Figure 15(A)), indicating that the pressure is weak. In other words, it is shown that the bathtub of Example 1 provides a lighter, more comfortable bathing experience for the feet than the bathtubs of Comparative Examples 1 and 2.

[0043] Also, it can be seen that the pressure distribution in the seat portion (area indicated by the symbol Y) in the case of the bathtub of Example 1 (see FIG. 15(C)) is smaller in the strongly pressurized areas and the pressure (body weight) is lighter than in the case of the bathtub of Comparative Example 2 (see FIG. 17(B)). Furthermore, it can be seen that the pressure distribution in the seat portion of the bathtub of Example 1 (see FIG. 15(C)) is smaller in the strongly pressurized areas and the pressure (body weight) is lighter than the pressure distribution in the seat portion of the bathtub of Comparative Example 1 (see FIG. 16(B)). In other words, the size of the strongly pressurized areas occurring in the seat portion has the following relationship: Example 1<Comparative Example 1<Comparative Example 2.

[0044] Furthermore, in the bathtub of Example 1, the area behind the knees (area indicated by the symbol Z) is supported by the calf support part 3 and body pressure is dispersed, so no areas of strong pressure appear, as shown in Fig. 15(B). In contrast, in the bathtub of Comparative Example 1, as shown in Fig. 16(B), areas of stronger pressure (areas shown darker) appear near the leading edge of the seat on the thighs than in the bathtub of Example 1, indicating that body pressure is concentrated.

[0045] In the bathtub according to the first embodiment, when the bather takes a lying-down bathing position with the back of the bather's head on the pillow 6 and the back supported by the backrest 1, the neck tilts slightly forward, the angle between the thighs and the back is 126° (within the range of the neutral position of 121° to 135°), the angle between the thighs and the legs is 148° (approximate to the angle of the neutral position of 125° to 141°), and the buttocks and thighs are supported by the seat 2, while the back of the knee, i.e., the lower thigh, i.e., the area close to the knee, and the upper calf, i.e., the area close to the knee, are supported by the calf support 3. Therefore, the lower leg bent at the knee joint is supported by the front downward inclined surface 15 of the calf support 3 and is in a position where it hangs down over the footrest 4.

[0046] This bathing posture is similar to the neutral posture, and allows the whole body to be relaxed, while the lower legs sink into the footrest 4, preventing the body from floating and reducing the sense of instability felt when bathing in a lying position. This provides the sensation of lying on one's back (as though lying down), while maintaining a stable bathing position. Neutral body posture is a posture concept proposed by NASA, and is the most natural posture formed when the whole body is relaxed in space. [Explanation of symbols]

[0047] 1 Backrest 2 Seat part 3 Calf support 4 Footrest 5 Armrest 6 Pillow part 7 Handrail 8. Drains 9 Drain (Drain fitting) 10 Floor surface 14. Calf support section with downward slope at rear 15 Calf support section with downward slope in front 16 Calf support section rising surface 19 Space on the raised surface of the calf support θ1 backrest angle θ2 Seat angle θ3 seat angle θ4 The angle between the rear and front downward slopes of the calf support (the angle of the top part of the seat)

Claims

1. The bathtub is equipped with a backrest that supports the bather's back, a seat that supports the buttocks, a calf support that supports the backs of the knees, and a footrest that is the deepest part of the bathtub. The calf support section of this bathtub is characterized in that it is composed of a rear downward inclined surface that supports the part of the thigh behind the bent knee of the bather close to the knee, a front downward inclined surface that supports the part of the calf close to the knee, and a rising surface that is connected to the footrest.

2. The bathtub according to claim 1, characterized in that the height difference between the calf support section and the footrest is such that when the buttocks are placed in the seat, both legs are stretched out naturally, and both heels are placed on the footrest, the calf support section lightly supports the backs of both knees, allowing the bather to assume a relaxed bathing posture.

3. The bathtub is equipped with a backrest that supports the bather's back, a seat that supports the buttocks, a calf support that supports the backs of the knees, and a footrest that is the deepest part of the bathtub. The calf support section is composed of a rear downward inclined surface that supports the area of ​​the thigh behind the bent knee of the bather, a front downward inclined surface that supports the area of ​​the calf near the knee, and a rising surface that connects to the foot rest area. A backrest angle θ of the backrest surface of the backrest portion with respect to a horizontal plane １ is 135° or less, while the seat surface angle θ ３ is set to 4° to 14°, which is a front upward slope toward the front side of the bathtub, and the backrest angle θ ２ 121° to less than 130°, and further, the angle θ between the front downward inclined surface and the rear downward inclined surface of the calf support portion ４ the inclination angle of the footrest is set to 125° to 153°, the height difference between the boundary between the front downward inclination surface and the rear downward inclination surface of the calf support part and the floor surface of the footrest area is set to 180 to 190 mm, and the height difference between the boundary between the front downward inclination surface and the rising surface of the calf support part and the floor surface of the footrest area is set to 130 mm to 140 mm.

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