JP7510606B2 - Bathtub equipment - Google Patents

Description

The present invention relates to a bathtub device, and in particular to a bathtub device equipped with an electrocardiogram signal detection function.

Bathing is not only done to keep the body clean, but also to relax while warming the body, relieve stress, and refresh both body and mind. In particular, in recent years, bathtubs equipped with various amenity functions have become common in ordinary homes, and more and more people are enjoying bathing. Meanwhile, the number of accidents in home bathtubs is about 20,000 per year, and the number of deaths is also on the rise, with elderly people accounting for the majority of deaths in bathtubs. In particular, while bathing warms the body and allows people to relax, bathing for an excessively long time can put a strain on the bather's heart, etc. As such, there is an increasing need to monitor the health of bathers in the bathtub.

JP 10-179529 A (Patent Document 1) describes an electrocardiogram examination device. This electrocardiogram examination device is configured to provide right and left electrodes on the inner wall surface of the bathtub and to obtain the bather's electrocardiogram. In addition, in the electrocardiogram examination device described in Patent Document 1, the right electrode is placed on the backrest surface of the bathtub against which the bather leans, and the left electrode is placed on the side wall surface adjacent to the backrest surface. By arranging the electrodes in the bathtub in this way, the bather leaning against the backrest surface of the bathtub is positioned in the space between the right and left electrodes, and the bather's electrocardiogram signal is obtained.

Japanese Utility Model Application Publication No. 2-61307 (Patent Document 2) describes a hydrocardiogram measuring device. In this hydrocardiogram measuring device, three electrodes constituting a negative pole, a positive pole, and a neutral point are arranged on the wall of the bathtub to obtain a first lead. In the hydrocardiogram measuring device described in Patent Document 2, a negative electrode is arranged on the upper part of the side wall adjacent to the right side of the backrest surface so as to be located near the right shoulder of the bather leaning against the backrest surface of the bathtub. In addition, a positive electrode is arranged on the lower part of the opposing side wall surface so as to be located near the left lower part of the bather's waist, and a neutral electrode is arranged on the surface facing the backrest surface near the bather's feet. In this way, in the hydrocardiogram measuring device described in Patent Document 2, the bather leaning against the backrest surface is positioned in the space between the positive electrode and the negative electrode to obtain an electrocardiogram. Patent Document 2 also describes arranging multiple auxiliary electrodes on the wall of the bathtub in addition to the negative, positive, and neutral electrodes described above in order to obtain leads other than the first lead, which has a large amplitude.

Japanese Patent Application Laid-Open No. 10-179529 Japanese Utility Model Application Publication No. 2-61307

However, when the inventions described in Patent Documents 1 and 2 are applied to a large bathtub, the signal waveform is attenuated, and an electrocardiogram signal with a sufficiently large amplitude cannot be detected. That is, in the inventions described in Patent Documents 1 and 2, one of the electrodes is placed on the side wall surface adjacent to the backrest surface of the bathtub in order to position the bather leaning against the backrest surface of the bathtub in the space between the positive electrode and the negative electrode. Therefore, if the detection electrode is applied to a bathtub with a wide backrest surface, the distance between the bather and the electrode becomes long, and the electrocardiogram signal cannot be detected with a sufficient amplitude. In addition, if one of the electrodes is placed on the side wall surface, the distance between the electrode and the bather's arm becomes short, and even a slight movement of the bather's arm can cause the electrocardiogram waveform to fluctuate, which can reduce the accuracy of obtaining the electrocardiogram signal.

The present invention therefore aims to provide a bathtub device that can detect electrocardiogram signals with sufficient amplitude even when applied to a bathtub with a wide backrest surface. It also aims to obtain highly accurate electrocardiogram signals even when the bather is moving his or her arms, etc.

In order to solve the above-mentioned problems, the present invention is a bathtub device equipped with an electrocardiogram detection function, which comprises a bathtub body formed in a substantially rectangular shape in a plan view, and a set of electrodes consisting of a positive electrode and a negative electrode attached to the bathtub body for detecting the bather's electrocardiogram signal via hot and cold water stored in the bathtub body, the set of electrodes being all disposed on a first inner wall surface constituting the short side of the bathtub body, and the positive electrode and negative electrode being disposed on the left and right, respectively, of a center line passing through the horizontal center of the first inner wall surface.

In the present invention thus configured, a set of electrodes consisting of a positive electrode and a negative electrode is arranged on the first inner wall surface of the bathtub body, which is formed in a substantially rectangular shape, and this set of electrodes detects the bather's electrocardiogram signal via the hot and cold water stored in the bathtub body. In addition, the set of electrodes consisting of a positive electrode and a negative electrode is both arranged on the first inner wall surface of the bathtub body, respectively on the left and right of the center line of the first inner wall surface.

According to the present invention configured in this way, a set of electrodes consisting of a positive electrode and a negative electrode are both arranged on the first inner wall surface that constitutes the short side of the bathtub body, so even when applied to a large bathtub body, the distance between the bather and each electrode does not become excessively long, and electrocardiogram signals can be detected with sufficient amplitude. Conventionally, when detecting the bather's electrocardiogram signal with electrodes attached to the bathtub body, as in the inventions described in Patent Documents 1 and 2, it was considered technical common sense to position the bather in the space between the electrodes to reliably capture the first lead. For this reason, at least one of the electrodes was provided on the side wall surface (the surface corresponding to the long side of the rectangle) adjacent to the inner wall surface on which the bather leans.

However, when the electrodes are provided on the side wall surface, in the case of a wide bathtub body (long short side), the distance between the bather's body and the electrodes becomes long, making it difficult to detect the electrocardiogram signal with sufficient amplitude. In addition, when at least one of the electrodes is provided on the side wall surface, the distance between the electrode and the bather's arm becomes short, and the electrocardiogram waveform fluctuates even when the bather moves his arm slightly, making it difficult to obtain an electrocardiogram signal with high accuracy. In response to this, the inventor of the present invention has continued to conduct research and development and has found that by focusing on the R wave in the electrocardiogram waveform in particular, it is possible to obtain an electrocardiogram signal with sufficient amplitude, and by calculating the heart rate and the like based on this, it is possible to monitor the thermal load on the body due to the thermal effect during bathing. This makes it clear that the electrocardiogram signal can be detected with sufficient amplitude even if the bather's body is not necessarily located in the space between the electrodes. According to the bathtub device of the present invention, since both the positive and negative electrodes are arranged on the first inner wall surface, it is possible to set the distance between the positive and negative electrodes regardless of the size of the bathtub body, and the electrocardiogram signal can be detected with sufficient amplitude. In addition, because the movement of the back while bathing is smaller than that of the arms, the device is less affected by changes in the bather's body movements, allowing for highly accurate measurement of electrocardiogram waveforms.

In the present invention, preferably, the sensor further comprises a reference electrode for detecting a reference potential, the reference electrode being disposed on the first inner wall surface.
Since the electrocardiogram signal is detected as a small potential difference between the positive and negative electrodes, it is preferable to obtain a reference potential in order to ensure the S/N ratio of the detection signal. According to the present invention configured as described above, the reference electrode is also arranged on the first inner wall surface on which the positive and negative electrodes are arranged, so that the surfaces on which the electrodes are arranged are concentrated on one surface, the electrical wiring connected to each electrode can be shortened, and the S/N ratio of the detection signal can be further improved. In addition, since the surfaces on which the electrodes are attached are concentrated on the first inner wall surface, the assembly during the manufacture of the bathtub body can be improved, and the maintainability can also be improved.

In the present invention, the positive electrode and the negative electrode are preferably arranged on the first inner wall surface, spaced apart from each other in the left and right direction from the center line.
In the present invention, the positive and negative electrodes are arranged on the first inner wall surface of the bathtub body, but even in this case, the positive and negative electrodes must be arranged on both sides of the bather's heart. Also, if the distance between the positive and negative electrodes is too close, the potential difference between the positive and negative electrodes becomes small, and an electrocardiogram signal cannot be obtained with sufficient amplitude. According to the present invention configured as described above, the positive and negative electrodes are arranged at a distance from the center line, so that the positive and negative electrodes can be arranged on both sides of the bather's heart leaning against the first inner wall surface of the bathtub body, and an electrocardiogram signal can be obtained with sufficient amplitude.

In the present invention, the distance in the left-right direction between the positive electrode and the negative electrode is preferably 700 mm or less.
The electrocardiogram signal obtained by the positive and negative electrodes is affected by the weight of the bather and the electrical conductivity of the hot water stored in the bathtub body. That is, when the weight of the bather is small or the electrical conductivity of the stored hot water is high (due to differences in water quality in different regions or the presence of bath additives, etc.), if the distance between the positive and negative electrodes is inappropriate, the electrocardiogram signal cannot be obtained with sufficient amplitude. According to the present invention configured as described above, the horizontal distance between the positive and negative electrodes is set to 700 mm or less, so that an electrocardiogram signal can be obtained with sufficient amplitude for a normal bather or for a normal electrical conductivity of hot water.

In the present invention, the distance in the left-right direction between the positive electrode and the negative electrode is preferably 380 mm or more.
In the present invention, since the positive and negative electrodes are provided on the first inner wall surface of the bathtub body, a bather leaning against the first inner wall surface may come into contact with the electrodes. When a bather comes into contact with the electrodes, a sudden change occurs in the potential of the electrodes, causing the baseline of the electrocardiogram signal to fluctuate significantly, and the performance of detecting the R-wave of the electrocardiogram signal, i.e., the performance of detecting the bather's heart rate, is significantly reduced. In response to this new technical problem, the inventor of the present invention has conducted intensive research and development and found that if the left-right distance between the positive and negative electrodes is set to 380 mm or more, the possibility of the bather's back coming into contact with the electrodes is extremely low. That is, it has been found that in about 95% of adult bathers, the contact width between the inner wall surface of the bathtub body and the bather's back is less than 380 mm. Therefore, by setting the left-right distance between the positive and negative electrodes to 380 mm or more, it is possible to effectively prevent a normal bather from coming into contact with the electrodes when he or she leans against the first inner wall surface in a normal posture.

The bathtub device of the present invention can detect electrocardiogram signals with sufficient amplitude even when applied to a bathtub with a wide backrest surface (first inner wall surface). In addition, highly accurate electrocardiogram signals can be obtained even when the bather is moving his or her arms.

1 is a perspective view showing an entire bathroom in which a bathtub apparatus according to an embodiment of the present invention is installed. 1 is a perspective view of a bathtub apparatus according to an embodiment of the present invention, seen obliquely from above. 1 is a cross-sectional view showing the structure of an electrode provided in a bathtub apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing the processing of signals acquired by electrodes of a bathtub apparatus according to an embodiment of the present invention. FIG. 13 is a block diagram showing a modified example of processing of signals acquired by electrodes of a bathtub apparatus according to an embodiment of the present invention. 1 is a diagram showing an example of an electrocardiogram signal measured by a bathtub apparatus according to an embodiment of the present invention. FIG. This is a diagram showing a schematic diagram of the positional relationship between the body of a bather leaning against the backrest surface of the bathtub body and each electrode attached to the backrest surface in a bathtub equipment according to an embodiment of the present invention. This is a diagram showing a schematic diagram of the positional relationship between the body of a bather leaning against the backrest surface of the bathtub body and each electrode attached to the backrest surface in a bathtub equipment according to an embodiment of the present invention. This is a diagram showing a schematic diagram of the positional relationship between the body of a bather leaning against the backrest surface of the bathtub body and each electrode attached to the backrest surface in a bathtub equipment according to an embodiment of the present invention.

Next, a bathtub apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Fig. 1 is a perspective view showing an entire bathroom in which a bathtub apparatus according to an embodiment of the present invention is installed. Fig. 2 is a perspective view of the bathtub apparatus according to an embodiment of the present invention, seen obliquely from above. Fig. 3 is a cross-sectional view showing the structure of electrodes provided in the bathtub apparatus according to an embodiment of the present invention. Fig. 4 is a block diagram showing the processing of signals acquired by the electrodes of the bathtub apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the bathtub apparatus 1 according to the embodiment of the present invention comprises a bathtub main body 2, a negative electrode 4a, a positive electrode 4b, and a reference electrode 4c attached to the bathtub main body 2, a signal processing device 6 that processes signals acquired by the electrodes, and a water discharge device 8 provided on the upper edge of the bathtub main body 2, and is installed in a bathroom R. A remote control 6a is also attached to the wall of the bathroom R, and the electrocardiogram signal detection function of the bathtub apparatus 1 and the water discharge device 8 can be operated using this remote control 6a. Furthermore, in this embodiment, the bathtub apparatus 1 is placed on one side of the bathroom R so that it is in contact with the wall.

The bathtub body 2 is formed in a substantially rectangular box shape in a plan view and is configured to store hot water inside. In this embodiment, the bathtub body 2 is arranged so that one long side and the entire two short sides on both sides are in contact with the inner wall surface of the bathroom R. In addition, the inner wall surface constituting one short side of the bathtub body 2 is configured as a backrest surface 2a, which is a first inner wall surface formed so that the bather can lean against it. In addition, an apron 2b is detachably attached to the long side of the bathtub body 2 on the side that is not in contact with the inner wall surface of the bathroom R. Here, the backrest surface is the inner wall surface that the bather's back contacts when bathing. The shape of the backrest surface does not need to be a strictly flat shape, and it is sufficient to have a substantially flat surface with a gently curved curved surface, and it may include a shape with steps or unevenness in part. Additionally, the shape of the bathtub body is generally rectangular, but is not limited to this, and may be any shape as long as the short sides that make up the backrest surface in a plan view are straight or have a gentle curve. For example, it may be a generally rectangular shape with gently curved sides. Additionally, the sides that face the backrest surface may have any shape.

The water discharge device 8 is provided on the upper part of the backrest surface 2a of the bathtub body 2, and is configured to discharge hot water toward the inside of the bathtub body 2. As shown in FIG. 2, in this embodiment, the water discharge device 8 has a flat, wide water discharge port 8a that extends along the upper edge of the backrest surface 2a, and is configured to discharge hot water toward the shoulders of the bather leaning against the backrest surface 2a. The water discharge device 8 also has a pump (not shown) that sucks in hot water stored in the bathtub body 2 and discharges it from the water discharge port 8a. Therefore, the hot water in the bathtub body 2 is sucked in by the pump (not shown), discharged from the water discharge port 8a, and circulates so that it flows into the bathtub body 2.

In addition, in this embodiment, the water outlet 8a of the water discharge device 8 is formed to be flat and wide, so that the hot water discharged from the water outlet 8a is discharged as a wide band-like water film and lands on the surface of the hot water stored in the bathtub body 2 at a position away from the backrest surface 2a. Furthermore, in this embodiment, the water discharge device 8 is configured so that the pressure strength applied by the pump (not shown) can be switched between three levels: "strong," "medium," and "weak." In the "strong" mode, hot water is discharged from the water outlet 8a at a flow rate of approximately 65 L/min, and the discharged hot water lands on the water surface in the bathtub body 2 at a position approximately 360 mm horizontally away from the water outlet 8a. In the "medium" mode, the water is discharged at a flow rate of about 55 L/min and hits the water surface at a position about 310 mm away from the water outlet 8a, and in the "weak" mode, the water is discharged at a flow rate of about 49 L/min and hits the water surface at a position about 280 mm away from the water outlet 8a. Note that these water landing positions are values measured when the water surface in the bathtub body 2 is about 300 mm above the bottom of the bathtub body 2. The water landing position here refers to the position where the water is discharged from the water outlet as a strip-like water film and hits the water surface of the water stored in the bathtub body, and does not include water landing at a position other than the originally intended position, such as splashes discharged from the water outlet or water flowing along the inner wall surface from the water outlet.

As shown in FIG. 2, the negative electrode 4a and the positive electrode 4b are a pair of electrodes attached to the bathtub body 2 in order to detect the bather's electrocardiogram signal through the hot and cold water stored in the bathtub body 2. The bather's electrocardiogram signal is obtained as a signal of the potential difference between the negative electrode 4a and the positive electrode 4b. The pair of electrodes consisting of the negative electrode 4a and the positive electrode 4b are both arranged on the backrest surface 2a that constitutes the short side of the bathtub body 2. The reference electrode 4c is an electrode for obtaining a reference potential of the potential detected by the negative electrode 4a and the positive electrode 4b, and this electrode is also arranged on the backrest surface 2a of the bathtub body 2.

In this way, in the bathtub apparatus 1 of this embodiment, all of the electrodes for acquiring electrocardiogram signals are arranged on one backrest surface 2a. In other words, in the bathtub apparatus 1 of this embodiment, electrocardiogram signals are detected only by the electrodes arranged on one backrest surface 2a.

As shown in FIG. 2, the negative electrode 4a and the positive electrode 4b are arranged on the left and right of the center line C in the horizontal direction (width direction) of the backrest surface 2a, at positions symmetrical with respect to the center line C. That is, the negative electrode 4a and the positive electrode 4b are arranged on the backrest surface 2a at a distance from the center line C in the left and right direction, and in this embodiment, the negative electrode 4a and the positive electrode 4b are arranged at a horizontal distance of about 380 mm. Furthermore, the negative electrode 4a and the positive electrode 4b are arranged at a height of about 300 mm from the bottom surface of the bathtub body 2 so as to be located below the water surface in the bathtub body 2. The negative electrode 4a and the positive electrode 4b can be attached at a height position below the water surface in the bathtub body 2 and above the reference electrode 4c. Preferably, the negative electrode 4a and the positive electrode 4b are arranged at a height of about 150 mm to about 450 mm from the bottom surface, slightly below the height of the water surface in the bathtub body 2 during normal use of the bathtub device 1. More preferably, the negative electrode 4a and the positive electrode 4b are disposed at a height of approximately 250 mm to approximately 350 mm from the bottom surface.

On the other hand, the reference electrode 4c is located on the center line C of the backrest surface 2a, below the negative electrode 4a and the positive electrode 4b. In this embodiment, the reference electrode 4c is located at a height of about 150 mm from the bottom surface of the bathtub body 2 so that it is located below the water surface in the bathtub body 2. Also, the reference electrode 4c is not necessarily provided and can be omitted.

Next, the structure of each electrode will be described with reference to FIG.
Although the structure of the negative electrode 4a will be described here, in this embodiment, the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c all have the same structure.

As shown in FIG. 3, the negative electrode 4a has an electrode portion 10, a front gasket 12a, a rear gasket 12b, a flange 14, a moisture-proof tube 16, a connection terminal 18, a fixing screw 20, a conductor 22, and a sheath 24. The negative electrode 4a is attached so as to be exposed on the surface of the backrest surface 2a of the bathtub body 2, and the gasket ensures watertightness between the negative electrode 4a and the backrest surface 2a.

The electrode section 10 is a conductive metal part, and is composed of a disk section 10a formed in a disk shape and a shaft section 10b protruding vertically from the back of the disk section 10a. The disk section 10a is a thin disk-shaped part, and the front surface of the disk section 10a is exposed on the surface of the backrest surface 2a and is configured to detect the electric potential. That is, in this embodiment, the disk section 10a is formed with a diameter of about 15 mm and a thickness of about 2.5 mm, and the entire disk section 10a is disposed on the surface of the backrest surface 2a. The shaft section 10b is a round bar-shaped part extending at a right angle from the center of the back of the disk section 10a, and protrudes to the back side of the backrest surface 2a through a through hole formed in the backrest surface 2a. In addition, a male screw thread is formed in the middle part of the shaft section 10b, and a fixing section for fixing the connection terminal 18 is formed at the tip.

The front gasket 12a is a disc-shaped member made of rubber, and has a circular hole in the center for passing the shaft portion 10b of the electrode portion 10 through. The front gasket 12a has approximately the same diameter as the disc portion 10a of the electrode portion 10, and is disposed on the rear side of the disc portion 10a. When the negative electrode 4a is attached to the backrest surface 2a, the front gasket 12a is sandwiched between the rear side of the disc portion 10a and the surface of the backrest surface 2a, ensuring watertightness between the backrest surface 2a and the negative electrode 4a.

The back gasket 12b is a disc-shaped member made of rubber, and has a circular hole in the center for passing the shaft portion 10b of the electrode portion 10 through. The back gasket 12b has a diameter larger than that of the front gasket 12a and is approximately the same as the large diameter portion of the flange 14, and is placed on the back side of the backrest surface 2a. When the negative electrode 4a is attached to the backrest surface 2a, the back gasket 12b is sandwiched between the back surface of the backrest surface 2a and the end face of the flange 14, ensuring watertightness between the rear surface of the backrest surface 2a and the negative electrode 4a. The front gasket 12a and the back gasket 12b may be made of resin.

The flange 14 is a stepped cylindrical member consisting of a large diameter portion and a small diameter portion, and a female thread is formed in the center to allow the shaft portion 10b of the electrode portion 10 to pass through. The large diameter portion of the flange 14 is formed to have approximately the same diameter as the back gasket 12b, and the small diameter portion is formed on the back side of the large diameter portion. By screwing and tightening the female thread formed to pass through the flange 14 and the male thread formed on the shaft portion 10b of the electrode portion 10, the end face of the large diameter portion of the flange 14 presses the back gasket 12b against the back of the backrest surface 2a, ensuring watertightness.

The moisture-proof tube 16 is a long, thin tube made of rubber, and is arranged to cover the tip of the shaft portion 10b of the electrode portion 10, the connection terminal 18, the conductor wire 22, etc. The small diameter portion of the flange 14 is fitted into the tip of the moisture-proof tube 16 to prevent moisture from entering the moisture-proof tube 16. The moisture-proof tube 16 may be made of resin.

The connection terminal 18 is a conductive metal component, and is crimped and connected to the tip of the conductor 22. A hole is provided at the tip of the connection terminal 18 for passing a fixing screw 20 through, and the connection terminal 18 can be fixed to the electrode part 10 by threading the fixing screw 20 through this hole into a female thread provided at the tip of the shaft part 10b of the electrode part 10. This allows the electrode part 10 and the conductor 22 to be electrically connected in a detachable manner.

The conductor 22 is a conductive wire for electrically connecting the electrode unit 10 and the signal processing device 6 (Figure 1), and extends from the negative electrode 4a to the signal processing device 6. The conductor 22 is covered with a sheath 24 made of an insulating material to ensure electrical insulation of the conductor 22. In this embodiment, the conductors 22 extending from the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c are connected to the signal processing device 6, and the electrocardiogram signal is input to the signal processing device 6.

Next, the configuration of the signal processing device 6 will be described with reference to FIG. 4A.
The signal processing device 6 is an electric circuit to which the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c are connected, and is disposed on the rear side of the backrest surface 2a of the bathtub body 2. The signals acquired by the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c are processed by the signal processing device 6, and the processing results are displayed on a remote control 6a disposed in the bathroom R and/or a display device (not shown) disposed outside the bathroom R.

As shown in FIG. 4A, the signal processing device 6 has a differential amplifier circuit 26, a filter circuit 28, an amplifier circuit 30, an A/D converter 32, and an interface circuit 34, and these circuits are contained within a housing 6b.
The differential amplifier circuit 26 is an amplifier circuit to which the conductors 22 extending from the negative electrode 4a and the positive electrode 4b are connected, and is configured to amplify the difference voltage between the negative electrode 4a and the positive electrode 4b.

The filter circuit 28 is configured to receive the differential voltage amplified by the differential amplifier circuit 26, remove unnecessary frequency band components such as hum, and pass signal components in a required frequency band.
The amplifier circuit 30 is configured to amplify a signal from which unnecessary frequency band components such as hum have been removed by the filter circuit 28. The conductor 22 extending from the reference electrode 4c is connected to the differential amplifier circuit 26, the filter circuit 28, and the ground of the amplifier circuit 30.

The A/D converter 32 is configured to convert the analog signal amplified by the amplifier circuit 30 into a digital signal.
The interface circuit 34 is configured to receive the digital signal converted from A/D by the A/D converter 32 and send the input digital signal to the remote control 6a and/or an external display device (not shown). The remote control 6a includes a recording unit 36a, a display unit 36b, a heart rate conversion unit 36c, and other components as an arithmetic processing unit. The signal sent from the signal processing device 6 is recorded in the recording unit 36a, and the bather's electrocardiogram waveform is displayed in a graph on the display unit 36b. The heart rate conversion unit 36c calculates the bather's heart rate based on the signal sent from the signal processing device 6, and the calculated heart rate of the bather is displayed numerically on the display unit 36b. The electrocardiogram waveform and the bather's heart rate can also be displayed on a display device (not shown) outside the bathroom R, so that the bather's health condition can be monitored from outside the bathroom R. Alternatively, the present invention can be configured to include the recording unit 36a and the heart rate conversion unit 36c in a display device (not shown) outside the bathroom R.

Here, the conductors 22 extending from each electrode and the signal processing device 6 to which these conductors 22 are connected are all housed in the space behind the backrest surface 2a of the bathtub body 2. As shown in FIG. 1, the space behind the backrest surface 2a can be accessed from the washing area side of the bathroom R by removing the apron 2b of the bathtub body 2. Therefore, maintenance such as adjustment and repair of each electrode and the signal processing device 6 can be easily performed simply by removing the apron 2b of the bathtub body 2. In other words, by arranging the negative electrode 4a, positive electrode 4b, reference electrode 4c, and signal processing device 6 in a concentrated and easily accessible space, maintainability can be improved.

As a modified example, as shown in FIG. 4B, a calculation processing unit 36 can be disposed inside the signal processing device 6. That is, in the modified example shown in FIG. 4B, the digital signal converted by the A/D converter 32 is input to the calculation processing unit 36, where it is recorded and the bather's heart rate is calculated. The calculated heart rate and electrocardiogram waveform are sent to the remote control 6a via the interface circuit 34 and displayed on the display unit of the remote control 6a. The present invention can also be configured so that these heart rate and electrocardiogram waveform are also displayed on a display device (not shown) outside the bathroom R.

Next, the operation of the bathtub apparatus 1 according to the embodiment of the present invention will be described with reference to FIGS.
Fig. 5 is a diagram showing an example of an electrocardiogram signal measured by the bathtub equipment 1 according to the embodiment of the present invention. Figs. 6 to 8 are diagrams showing the positional relationship between the body B of a bather leaning against the backrest surface 2a of the bathtub main body 2 and each electrode attached to the backrest surface 2a.

First, the bather can operate the water discharge device 8 by operating the remote control 6a (Figure 1) attached to the wall of the bathroom R. When the water discharge device 8 is activated, a ribbon of hot water is discharged from the water outlet 8a provided on the upper part of the backrest surface 2a of the bathtub main body 2 toward the shoulders of the bather leaning against the backrest surface 2a. This discharge of hot water from the water discharge device 8 provides a thermal effect and a massage effect for the bather. Furthermore, the bather can operate the remote control 6a to activate the electrocardiogram signal detection function. The detected electrocardiogram signal is displayed on the display unit of the remote control 6a and on a display device (not shown) outside the bathroom R.

Figure 5 is an example of an electrocardiogram waveform detected by the bathtub device 1 of the embodiment of the present invention. As shown in Figure 5, the electrocardiogram waveform is a time series waveform in which peaks appear at regular time periods, and if the electrocardiogram waveform is properly measured, an electrocardiogram waveform with sufficient RS amplitude at the peak is obtained. In addition, the bather's heart rate can be calculated based on the time period in which the peak appears in the electrocardiogram waveform. By looking at the electrocardiogram waveform and heart rate displayed on the remote control 6a, the bather can objectively confirm that there is nothing abnormal in his or her health condition. In addition, the bather can objectively recognize that the time spent bathing in hot water discharged from the water discharge device 8 has become too long and changes have appeared in the electrocardiogram waveform and heart rate. Alternatively, by having the bather's family or the like watch the electrocardiogram waveform and heart rate displayed on a display device (not shown) installed outside the bathroom R, it is possible to recognize changes in the bather's health condition early on, and accidents during bathing can be prevented.

On the other hand, if the bather in the bathtub body 2 comes into direct contact with any of the electrodes, it will not be possible to obtain an appropriate electrocardiogram waveform as shown in FIG. 5. In this embodiment, the negative electrode 4a, positive electrode 4b, and reference electrode 4c are all attached and exposed to the surface of the backrest surface 2a against which the bather leans. However, because the curvature of the corners of the bathtub is greater than the curvature from the bather's back to his/her shoulders, a space is created between the bathtub and the bather. By arranging the electrodes in this space, contact between the bather's back or shoulders and each electrode is avoided.

Figures 6 to 8 are diagrams showing the positional relationship between the body B of the bather leaning against the backrest surface 2a of the bathtub body 2 and each electrode attached to the backrest surface 2a. As shown in Figure 6, when the bather leans against the center of the backrest surface 2a, the body B of the bather comes into contact with the backrest surface 2a between the negative electrode 4a and the positive electrode 4b, and the bather does not come into contact with the negative electrode 4a or the positive electrode 4b. That is, in this embodiment, the horizontal distance between the negative electrode 4a and the positive electrode 4b is about 380 mm, which is longer than the average width of the anterior armpit of an adult male, and the body B of the bather does not usually come into contact with the negative electrode 4a or the positive electrode 4b.

The backrest surface 2a of the bathtub body 2 is curved so as to protrude outward in a plan view, so that when a bather unconsciously leans against the backrest surface 2a, the bather's body B naturally comes to be positioned approximately in the center of the width of the backrest surface 2a. The reference electrode 4c is attached to the center of the backrest surface 2a, but because it is attached at a low position on the backrest surface 2a (Figure 2), the reference electrode 4c does not normally come into contact with the bather's body B. In other words, when a bather naturally leans against the backrest surface 2a, at the low position, the bather's back is away from the backrest surface 2a, and the reference electrode 4c does not come into contact with the bather.

On the other hand, as shown in Figure 7, when the bather leans against a corner of the bathtub body 2, the bather's body B comes into contact with the backrest surface 2a and the side wall surface 2c adjacent to the backrest surface 2a, straddling the positive electrode 4b, but does not come into contact with the positive electrode 4b. Similarly, when the bather leans against the corner on the opposite side to Figure 7, the bather's body B comes into contact with the backrest surface 2a and the side wall surface 2d adjacent to the backrest surface 2a, straddling the negative electrode 4a, but does not come into contact with the negative electrode 4a.

Furthermore, as shown in Figure 8, when the bather leans deeply against the backrest surface 2a of the bathtub body 2 (leaning so that the shoulders are at a low position), the bather's neck comes into contact with the upper end of the backrest surface 2a, straddling each electrode, and the bather's buttocks come into contact with the bottom surface of the bathtub body 2. Therefore, when the bather leans deeply, the bather's back barely comes into contact with the backrest surface 2a, and the bather's body B does not come into contact with the negative electrode 4a, the positive electrode 4b, or the reference electrode 4c.

As described above, the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c are arranged so as to be exposed on the backrest surface 2a of the bathtub body 2, but when the bather naturally leans against the backrest surface 2a, the bather's body B is usually not in contact with each electrode. This makes it possible to properly acquire the bather's electrocardiogram signal.

According to the bathtub device 1 of the embodiment of the present invention, a set of electrodes consisting of a positive electrode 4b and a negative electrode 4a are both arranged on the backrest surface 2a, which is the first inner wall surface that constitutes the short side of the bathtub body 2 (Figure 2), so even when applied to a large bathtub body 2, the distance between the bather and each electrode does not become excessively long, and electrocardiographic signals can be detected with sufficient amplitude. In addition, according to the bathtub device 1 of the present embodiment, since both the positive electrode 4b and the negative electrode 4a are arranged on the backrest surface 2a, it is possible to set the distance between the positive electrode 4b and the negative electrode 4a regardless of the size of the bathtub body 2, and electrocardiographic signals can be detected with sufficient amplitude.

In addition, according to the bathtub device 1 of this embodiment, the reference electrode 4c is also arranged on the backrest surface 2a where the positive electrode 4b and negative electrode 4a are arranged (Figure 2), so the surfaces on which the electrodes are arranged are concentrated on one surface, the electrical wiring connecting to each electrode can be shortened, and the S/N ratio of the detection signal can be further improved. In addition, because the surfaces on which each electrode is attached are concentrated on the backrest surface 2a, the assembly during manufacture of the bathtub body 2 can be improved, and the maintainability can also be improved.

Furthermore, according to the bathtub device 1 of this embodiment, the positive electrode 4b and the negative electrode 4a are each positioned away from the center line C, so that the positive electrode 4b and the negative electrode 4a can be positioned on either side of the bather's heart leaning against the first inner wall surface of the bathtub body, making it possible to obtain an electrocardiogram signal with sufficient amplitude.

In addition, according to the bathtub device 1 of this embodiment, the left-right distance between the positive electrode 4b and the negative electrode 4a is set to 700 mm or less, so that an electrocardiogram signal can be obtained with sufficient amplitude for a normal bather and for the normal electrical conductivity of hot and cold water. Furthermore, according to the bathtub device 1 of this embodiment, the left-right distance between the positive electrode 4b and the negative electrode 4a is set to 380 mm or more, so that when a normal bather leans against the backrest surface 2a in a normal posture, the bather can be effectively prevented from coming into contact with the electrodes.

Although an embodiment of the present invention has been described above, various modifications can be made to the above-mentioned embodiment. In particular, in the bathtub apparatus of the above-mentioned embodiment, a water discharge device is provided on the upper part of the backrest surface, but such a water discharge device can be omitted.

1 Bathtub device 2 Bathtub body 2a Backrest surface (first inner wall surface)
2b Apron 2c Side wall surface 2d Side wall surface 4a Negative electrode 4b Positive electrode 4c Reference electrode 6 Signal processing device 6a Remote control 6b Housing 8 Water discharge device 8a Water discharge port 10 Electrode portion 10a Disc portion 10b Shaft portion 12a Front packing 12b Rear packing 14 Flange 16 Moisture-proof tube 18 Connection terminal 20 Fixing screw 22 Conductor 24 Sheath 26 Differential amplifier circuit 28 Filter circuit 30 Amplification circuit 32 A/D converter 34 Interface circuit

Claims (4)

A bathtub device equipped with an electrocardiogram signal detection function,
A bathtub body formed into a substantially rectangular shape in a plan view;
A set of electrodes consisting of a positive electrode and a negative electrode attached to the bathtub body for detecting the bather's electrocardiogram signal via the hot and cold water stored in the bathtub body;
A reference electrode for detecting a reference potential;
A bathtub apparatus characterized in that the set of electrodes are all arranged on a first inner wall surface that constitutes the short side of the bathtub body, the positive electrode and the negative electrode are respectively arranged on the left and right of a center line passing through the horizontal center of the first inner wall surface, and the reference electrode is arranged on the first inner wall surface. 2. The bathtub apparatus according to claim 1 , wherein the positive electrode and the negative electrode are disposed on the first inner wall surface, spaced apart from each other in the left and right direction from the center line. 3. The bathtub apparatus according to claim 2 , wherein the distance in the left-right direction between the positive electrode and the negative electrode is 700 mm or less. 3. The bathtub apparatus according to claim 2 , wherein the distance in the left-right direction between the positive electrode and the negative electrode is 380 mm or more.

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