Electric bed catching-in detection device

Abstract

To prevent catching-in of a body of a user in an electric bed.SOLUTION: A bed 1 includes: a displacement mechanism 10 for displacing a mattress 5; an electric motor 15 for driving the displacement mechanism 10; and space defining parts 35 for defining a space part 30 to be variable in size in response to the displacement of the mattress 5. The bed 1 includes a catching-in detection device 50. The catching-in detection device 50 includes: capacitive sensors 60 arranged in the space defining parts 35 so as to detect existence of a body in the space part 30; and a control device 70 for disabling an operation of the electric motor 15 when the capacitive sensor 60 detects the existence.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pinch detection device for an electric bed. [Background technology]

[0002] If a user of an electric bed has their arm inserted through a gap in the side rail and the mattress is raised, there is a risk that the arm may become caught between the components of the electric bed.To address this issue, Patent Document 1 discloses a bed that is configured to reverse the rotation of the motor for raising the back when the load current flowing through the motor exceeds a predetermined value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4189195 Summary of the Invention [Problem to be solved by the invention]

[0004] The bed described above detects whether a user is currently trapped between bed components based on the load acting on the user's body when the user is trapped. Only after a load acts on the user does the motor reverse rotation to reduce the load. It would be preferable if the bed could detect a body trap or a sign of such trapping earlier.

[0005] An object of the present invention is to prevent a body from being trapped in an electric bed. [Means for solving the problem]

[0006] One aspect of the present invention provides an entrapment detection device for an electric bed that is provided with a displacement mechanism that displaces a bed section, an electric motor that drives the displacement mechanism, and a gap defining section that defines a gap section whose size can be changed according to the displacement of the bed section, the entrapment detection device for an electric bed comprising: a capacitance sensor that is installed in the gap defining section and that detects the presence of a body in the gap section; and a control device that is configured to disable the electric motor when the capacitance sensor detects the presence.

[0007] According to the above configuration, if the floor section is displaced while the user's body is present in the gap, the change in size of the gap may cause the user's body to become trapped in the gap defining section. Therefore, a capacitance sensor is installed in the gap defining section, which defines the gap whose size changes depending on the displacement of the floor section, to detect the presence of the body in the gap. Once the presence of the body in the gap is detected, the electric motor becomes inoperable. This prevents the user's body from actually becoming trapped in the gap defining section. [Effects of the Invention]

[0008] According to the present invention, it is possible to prevent a body from being caught in an electric bed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a bed to which a pinch detection device according to an embodiment is applied; [Figure 2] 1 is a block diagram conceptually showing the configuration of a pinch detection device according to an embodiment; [Figure 3A] 1 is a schematic side view of a bed according to an embodiment, showing a state in which the back of a mattress is in a horizontal position. [Figure 3B] 3B is a schematic side view of a bed according to a comparative example, showing a state in which the size of the side rail gap has been reduced from that in FIG. 3A in response to the back being raised. FIG. [Figure 4A] 1 is a schematic side view of a bed according to an embodiment, showing a state in which the back of the mattress is in a somewhat upright position. [Figure 4B] 4B is a schematic side view of a bed according to a comparative example, showing a state in which the size of the back and underside space has been reduced from that of FIG. 4A in response to the back being lowered. FIG. [Figure 5A] 1 is a schematic side view of a bed according to an embodiment, showing a state in which a mattress is in a somewhat elevated position. FIG. [Figure 5B] 5B is a schematic side view of a bed according to a comparative example, showing a state in which the size of the base space has been reduced from that of FIG. 5A in response to the lowering of the mattress. FIG. [Figure 6] Cross-sectional view showing the side fence gap and bottom space. [Figure 7] FIG. 10 is a block diagram conceptually showing the configuration of a pinch detection device according to a first modified example. [Figure 8] FIG. 10 is a block diagram conceptually showing the configuration of a pinch detection device according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or corresponding elements are designated by the same reference numerals throughout the drawings, and redundant explanations will be omitted.

[0011] FIG. 1 shows an electric bed 1 to which an entrapment detection device 50 (see FIG. 2) according to an embodiment is applied. The bed 1 can be installed in, for example, a hospital or a nursing home. In this document, the term "user" refers to a reclining person, a visitor, or both, depending on the context. A reclining person is a person who is currently lying in the bed 1 (a user in the narrow sense). A visitor is a person who is around the bed 1 to attend to the reclining person, for example, in the event of visiting, caring for, nursing, or medical treatment, or to set up or regularly inspect the bed 1.

[0012] Bed 1 is rectangular in plan view. Hereinafter, the direction in which the long sides of the rectangle extend will be referred to as the "longitudinal direction," and the direction in which the short sides extend will be referred to as the "width direction." When bed 1 is properly placed on a level floor, the longitudinal and width directions are horizontal. The user lies on bed 1 with their head facing one side in the longitudinal direction (the right side of the paper in Figure 1) and their feet facing the other side in the longitudinal direction (the left side of the paper in Figure 1).

[0013] The bed 1 comprises a base frame 2, four casters 3, a bed frame 4, a mattress 5, a headboard 6, a footboard 7, and a pair of side rails 8. The number of casters 3 and side rails 8 is not particularly limited. The bed frame 4 and the mattress 5 form at least a part of the floor of the bed 1. The mattress 5 may be fixed to the bed 1, or may be supported on the bed frame 4 in a replaceable or detachable manner.

[0014] The base frame 2 has a rectangular window frame shape in a plan view. The base frame 2 includes a pair of longitudinal frames 2a (only one of which is shown) extending in the longitudinal direction, and a pair of width frames (not shown) connecting the ends of the pair of longitudinal frames 2a. The base frame 2 is supported on the floor surface via four casters 3 (only three of which are shown) attached to each of the four corners. The bed frame 4 is disposed above the base frame 2 and is supported so as to be displaceable relative to the base frame 2. In this document, "displacement" refers to a change in at least one of position and posture. The bed frame 4 includes at least a pair of side frames 4a extending in the longitudinal direction.

[0015] The mattress 5 has a rectangular shape in a plan view, and is supported by the bed frame 4 so as to cover it from above. The mattress 5 is surrounded by a headboard 6, a footboard 7, and a pair of side rails 8. The mattress 5 is disposed between the headboard 6 and the footboard 7 in the longitudinal direction, and between the pair of side rails 8 in the width direction.

[0016] The headboard 6 is erected at one longitudinal end of the base frame 2 and is arranged on one longitudinal side of the mattress 5. The footboard 7 is erected at the other longitudinal end of the base frame 2 and is arranged on the other longitudinal side of the mattress 5. The headboard 6 and footboard 7 extend in the vertical and width directions. A pair of side rails 8 are erected on each of the pair of side frames 4a and are arranged on both widthwise sides of the mattress 5. The side rails 8 extend in the vertical and longitudinal directions.

[0017] Fig. 2 conceptually shows the configuration of bed 1. With reference to Figs. 1 and 2, bed 1 includes an electric unit 9 that electrically displaces mattress 5. Electric unit 9 includes a displacement mechanism 10 that displaces mattress 5, which is an example of a bed portion, in a vertical or undulating direction, an electric motor 15 that drives displacement mechanism 10, an operating member 20 that is operated by the user, and a power supply unit 25 that operates electric motor 15 in response to operation of operating member 20.

[0018] The displacement mechanism 10 includes a lifting mechanism 11 and a back-raising mechanism 12. The lifting mechanism 11 and the back-raising mechanism 12 may be of any type, such as an arm type or a scissor type. The electric motor 15 includes a lifting motor 16 that drives the lifting mechanism 11 and a back-raising motor 17 that drives the back-raising mechanism 12. The electric motor 15 is capable of rotating forward and backward.

[0019] The lifting mechanism 11 raises or lowers the entire bed frame 4 and mattress 5 relative to the base frame 2 depending on the rotation direction of the lifting motor 16.

[0020] The back-raising mechanism 12 raises or lowers the back portion 5a of the mattress 5 relative to the base frame 2 depending on the rotation direction of the back-raising motor 17. Hereinafter, the raising action of the back portion 5a may be referred to as "raising the back" and the lowering action of the back portion 5a may be referred to as "lowering the back." The back portion 5a is located on one side of the mattress 5 in the longitudinal direction, and supports the back of the head and back of a user lying face-up on the mattress 5. By raising the back, the user's upper body can be gradually raised. By lowering the back, the user's upper body can be gradually lowered.

[0021] The operating member 20 is an element that allows the user to remotely control the position and posture of the mattress 5. Although detailed illustration is omitted, the operating member 20 is provided with, for example, a plurality of button-type switches that are pushed by the user. Examples of such switches include an up switch for operating the lifting mechanism 11 to raise the entire mattress 5, a down switch for operating the lifting mechanism 11 to lower the entire mattress 5, a back-raising switch for operating the back-raising mechanism 12 to raise the back portion 5a, and a back-lowering switch for operating the back-raising mechanism 12 to lower the back portion 5a.

[0022] The power supply unit 25 is connected to an external power source 90, such as a commercial power source or an in-hospital power generator. The power supply unit 25 is further connected to the electric motor 15 and the operating member 20. While a switch on the operating member 20 is being pushed, the power supply unit 25 supplies power to the electric motor 15 corresponding to that switch, causing the electric motor 15 to rotate in the direction corresponding to that switch. This causes a displacement in the mattress 5 corresponding to that switch. When the push operation is released, the electric motor 15 stops, and the mattress 5 is maintained in the position and posture at the time of release of the operation.

[0023] 2, the bed 1 is provided with a pinch detection device 50. The pinch detection device 50 detects signs that the user's body may be pinched in the gap defining portion 35 that defines the gap 30 of the bed 1, before the pinch actually occurs and a load is applied to the user's body. When the size of the gap 30 is variable depending on the displacement of the mattress 5, pinch can occur in the process of the size of the gap 30 decreasing due to the displacement of the mattress 5.

[0024] To prevent such entrapment, the entrapment detection device 50 is equipped with a capacitance sensor 60 that detects the presence of a body in the size-variable gap 30. The capacitance sensor 60 is installed in the gap defining portion 35. As shown in FIG. 1 , in the bed 1 described above, examples of such size-variable gaps 30 include the side rail gap 31, the back and rear space 32, and the bottom space 33. At least the cross member 8b of the side rail 8 to which the side rail sensor 61 is attached is preferably made of an insulating material such as resin that is less affected by detection of changes in capacitance.

[0025] Fig. 3A shows bed 1 according to this embodiment. Fig. 3B shows bed 101 according to a comparative example that does not have a pinch detection device. Bed 101 according to the comparative example has the same configuration as bed 1 according to this embodiment, except for the presence or absence of a pinch detection device.

[0026] 3A and 3B, the side fence 8 has an outer frame 8a that resembles a rectangular window frame in side view, and multiple horizontal members 8b arranged at intervals in the vertical direction inside the outer frame 8a. Each horizontal member 8b extends in the longitudinal direction, with both ends joined to the outer frame 8a. For each side fence 8, multiple side fence gaps 31 are defined by the outer frame 8a and the horizontal members 8b, separated by the horizontal members 8b, and arranged in the vertical direction. Visitors can see through the side fence gaps 31 from the outside of the width of the bed 1 to the surface area of ​​the mattress 5 where the reclining person is located.

[0027] When the mattress 5 is raised or lowered, the polygonal shape formed by the surface of the mattress 5 and the cross member 8b changes in side view. With respect to the bottommost side fence gap 31, in FIG. 3A the polygonal shape is rectangular, whereas in FIG. 3B the surface of the mattress 5 is inclined relative to the cross member 8b due to the back-raising, and the polygonal shape is trapezoidal. Therefore, the size of the space on the surface side of the mattress 5 that can be seen through the side fence gap 31 changes. In other words, the size of the side fence gap 31 changes substantially.

[0028] Now, let's consider a case where the recumbent's arm is sticking out of bed 1 through side rail gap 31. As shown in FIG. 3A, when back 5a is in a horizontal position, the arm is not compressed, and no strain is placed on the recumbent. On the other hand, as shown in FIG. 3B, when the size of side rail gap 31 is substantially reduced by raising the back, there is a risk that the arm may become pinched between side rail 8 and the surface of mattress 5. In bed 101 according to the comparative example, it is difficult to prevent this pinching.

[0029] As shown in FIG. 3A, in this embodiment, side fence sensors 61, as an example of capacitance sensors 60, are installed on the upper edges (gap defining portions 35) of the cross members 8b and outer frame 8a. The side fence sensors 61 are cable-like, extend longitudinally while crawling along the underside of the gap defining portions 35, and are installed on the upper edges of the side fence gaps 31. Each side fence sensor 61 can detect, in a non-contact manner, whether or not a body (e.g., an arm or leg of a person lying down) is present in the side fence gap 31 immediately below it. As will be described later, based on the detection results of the side fence sensors 61, it is possible to prevent an arm or leg inserted into the side fence gap 31 from getting caught.

[0030] The capacitance sensor 60 of this embodiment can detect the presence of a body without contact, but the degree of non-contact can be tuned. By lowering the threshold value of the change in capacitance that triggers stopping the electric motor 15, the presence of a body can be detected even when it is far away, and the electric motor 15 can be stopped. By raising the threshold value of the change in capacitance, the electric motor 15 can be stopped at a timing when it is very close, almost to contact. Although detection is somewhat slower, the electric motor 15 is stopped only when the presence of a body nearby is detected, which prevents the electric motor 15 from being stopped due to erroneous detection.

[0031] FIG. 4A shows the bed 1 according to this embodiment, and FIG. 4B shows a bed 101 according to a comparative example. Referring to FIGS. 4A and 4B, when the back 5a is upright, a back-back space 32 is formed surrounded by the underside of the back 5a, the bed frame 4, and the headboard 6 (FIG. 4A). Lowering the back reduces the back-back space 32 (FIG. 4B). When the back 5a is reclined until it is horizontal, the back-back space 32 disappears (FIG. 3A). Thus, the back-back space 32 is an example of a gap 30 whose size is reduced in response to lowering the back. The underside of the back 5a is an example of a gap defining portion 35 that defines the gap 30.

[0032] Now, let's consider a case where a visitor's arm is inserted into the back space 32. As shown in FIG. 4A, when the back 5a is upright, the arm is not compressed, and no strain is placed on the visitor. On the other hand, as shown in FIG. 4B, when the back space 32 is reduced in size by lowering the back, there is a risk that the arm may become trapped between the back 5a and the bed frame 4. In the bed 101 according to the comparative example, it is difficult to prevent this trapping.

[0033] As shown in FIG. 4A, in this embodiment, a back sensor 62, as an example of a capacitance sensor 60, is installed on the back surface (gap defining portion 35) of the back portion 5a of the mattress 5. The back sensor 62 may be in the form of a cable or a sheet. The back sensor 62 can detect in a non-contact manner whether or not a body (e.g., a visitor's arm) is present in the back space 32. As will be described later, based on the detection result of the back sensor 62, it is possible to prevent an arm inserted into the back space 32 from getting caught.

[0034] FIG. 5A shows a bed 1 according to this embodiment, and FIG. 5B shows a bed 101 according to a comparative example. Referring to FIGS. 5A and 5B, a floor space 33 is formed in the vertical direction between the underside of the mattress 5 and the floor surface on which the bed 1 is placed. This floor space 33 is formed inside the base frame 2, which has a rectangular window frame shape in a plan view. As the mattress 5 is lowered, the floor space 33 is reduced in the vertical direction (FIG. 5B). The floor space 33 is an example of a gap portion 30 whose size is reduced as the mattress 5 is lowered. The base frame 2 is an example of a gap defining portion 35 that defines such a gap portion 30.

[0035] Now, let us consider a case where a child visitor crawls into the floor space 33. As shown in FIG. 5A, when the mattress 5 is in a somewhat elevated position, the visitor can crawl completely into the floor space 33, and no strain is placed on the visitor. On the other hand, as shown in FIG. 5B, when the mattress 5 is lowered and the size of the floor space 33 shrinks, there is a risk that almost the entire body will become pinched between the floor and the mattress 5. In the bed 101 according to the comparative example, it is difficult to prevent this pinching.

[0036] As shown in FIG. 5A, in this embodiment, a base sensor 63, as an example of a capacitance sensor 60, is installed on the longitudinal frame 2a of the base frame 2. The base sensor 63 is cable-like and extends in the longitudinal direction, crawling along the upper surface of the longitudinal frame 2a. The base sensor 63 can detect in a non-contact manner whether a body has climbed over the base frame 2 and is present in the floor space 33. As will be described later, based on the detection result of the base sensor 63, it is possible to prevent a body that has slipped into the floor space 33 from being pinched.

[0037] Referring to Figure 6, the capacitance sensor 60 (particularly the side fence sensor 61 and base sensor 63) is a flexible tubular (cable) structure. The capacitance sensor 60 has a coaxial resin core wire 60a, a braided wire 60b made of copper or the like, and a coating 60c, which are layered radially outward in this order from the axial core. The capacitance sensor 60 can detect the presence of a body at any axial position without contact.

[0038] Returning to FIG. 2 , the pinch detection device 50 further includes a control device 70. The control device 70 includes, for example, a central processing unit (CPU) or a micro processing unit (MPU) that implements predetermined functions in cooperation with software. The control device 70 may be configured with hardware circuits such as dedicated electronic circuits or reconfigurable electronic circuits designed to implement predetermined functions, or may be configured with various semiconductor integrated circuits. Examples of various semiconductor integrated circuits include a CPU, an MPU, a microcomputer, a digital signal processor (DSP), a field programmable gate array (FPGA), and an application specific integrated circuit (ASIC). The control device 70 may also include storage devices such as a random access memory (RAM) and a read only memory (ROM).

[0039] The control device 70 is configured to disable the electric motor 15 when the capacitance sensor 60 detects the presence of a body. Furthermore, the control device 70 is configured to release the disabled state of the electric motor 15 when a predetermined release condition is met after the electric motor 15 has been disabled. The control device 70 has a stop determination unit 71 as a functional block that executes such control.

[0040] The pinch detection device 50 includes a switch 51 that is interposed in a circuit that supplies power from an external power source 90 to the electric motor 15 via the power supply unit 25, or in a circuit that outputs an operation signal from the operating member 20 to the power supply unit 25. When the switch 51 is switched between open and closed, the electric motor 15 is switched between an operable state and an inoperable state.

[0041] In this embodiment, the switch 51 is interposed in a circuit that connects the power supply unit 25 to the external power supply 90. The power supply unit 25 is connected to the external power supply 90 via a power supply line. The power supply line includes an internal circuit of the control device 70. In this case, the switch 51 may be mounted on a board that constitutes the control device 70 and be able to open and close the internal circuit.

[0042] The stop determination unit 71 monitors the detection signal from the capacitance sensor 60. If the capacitance sensors 60 (all of the side fence sensors 61, back and rear sensors 62, and base sensor 63) output an OFF signal indicating that no body is present, the stop determination unit 71 opens the switch 51 and maintains the operable state of the electric motor 15. In other words, if no body is inserted into any of the side fence gaps 31, back and rear spaces 32, and bottom space 33, the user can remotely control the displacement of the mattress 5 using the operating member 20.

[0043] When the capacitance sensor 60 (at least one of the side fence sensor 61, back and rear sensor 62, and base sensor 63) outputs an ON signal indicating the presence of a body, the stop determination unit 71 closes the switch 51 and switches the electric motor 15 to an inoperable state. In other words, if the body is inserted into at least one of the side fence gap 31, back and rear space 32, and bottom space 33, operation of the operating member 20 is invalid even if no load is acting on the body from the components of the bed 1. Even if the user operates the operating member 20, the mattress 5 cannot be displaced. This makes it possible to prevent pinching as shown in Figures 3B, 4B, and 5B.

[0044] The entrapment detection device 50 further includes an alarm 52. When the capacitance sensor 60 outputs an ON signal, the stop determination unit 71 switches the electric motor 15 to an inoperable state and simultaneously activates the alarm 52. This allows the user to know that displacement of the mattress 5 is prohibited due to the risk of entrapment. The alarm 52 may be an audible alarm for the user, such as a buzzer or speaker, or a visual alarm for the user, such as a lamp or display, or both.

[0045] After switching the electric motor 15 to the inoperable state, the stop determination unit 71 determines whether a predetermined release condition is met. If the release condition is not met, the switch 51 is kept open, and the electric motor 15 is kept in the inoperable state. If the release condition is met, the switch 51 is switched from open to closed. The electric motor 15 is switched from the inoperable state to the operable state, and operation with the operating member 20 becomes valid. The user can remotely control the displacement of the mattress 5 using the operating member 20.

[0046] The release condition may be that a release switch 53 provided in the entrapment detection device 50 has been operated. The release switch 53 may be provided integrally with the operating member 20, or may be provided in a location on the bed 1 separate from the operating member 20. The release switch 53 is connected to the control device 70. When the release switch 53 is operated and a release signal is output to the control device 70, the stop determination unit 71 determines that the release condition has been met, and releases the inoperable state of the electric motor 15.

[0047] In addition to the above, the release conditions may include a condition that the capacitance sensors 60 (all of the side fence sensors 61, the back sensor 62, and the base sensor 63) no longer detect the presence of a body (i.e., a condition that the capacitance sensors 60 have returned to a state in which they output an OFF signal), and a condition that a set time (e.g., 30 seconds) has elapsed since the electric motor 15 was disabled. The release condition may be met when at least one of the multiple conditions exemplified here is met. The release condition may also be met when all of the multiple conditions exemplified here are met.

[0048] Thus, the pinch detection device 50 according to this embodiment is provided in a bed 1 that includes a displacement mechanism 10 that displaces the mattress 5, which is part of the bed portion, an electric motor 15 that drives the displacement mechanism 10, and a gap defining portion 35 that defines a gap 30 whose size is variable in accordance with the displacement of the mattress 5. The pinch detection device 50 includes a capacitance sensor 60 that is installed in the gap defining portion 35 and that detects the presence of a body in the gap 30, and a control device 70 that is configured to disable the electric motor 15 when the capacitance sensor 60 detects the presence.

[0049] In the above configuration, the capacitance sensor 60 is installed in the gap defining portion 35 that defines the gap 30, the size of which varies depending on the displacement of the mattress 5, and detects the presence of a body in the gap 30. When the presence of a body in the gap 30 is detected, the operating member 20 is disabled and the electric motor 15 becomes inoperable. This makes it possible to prevent the body from actually becoming trapped in the gap defining portion 35.

[0050] The bed 1 further comprises a side rail 8 arranged on the side of the mattress 5, the displacement mechanism 10 includes a back-raising mechanism 12 that raises and lowers the back portion 5a of the mattress 5, the gap portion 30 includes a side rail gap 31 that changes size in a side view according to the rise and fall of the back portion 5a, and a capacitance sensor 60 is installed in the side rail 8 as a gap defining portion 35. This makes it possible to prevent a body from getting caught in the side rail gap 31 even if the body is inserted into the side rail gap 31.

[0051] The displacement mechanism 10 includes a back-raising mechanism 12 that raises and lowers the back portion 5a of the mattress 5, the gap portion 30 includes a back-back space 32 that reduces in size as the back portion 5a is lowered, and the capacitance sensor 60 is installed on the back side of the back portion 5a as a gap defining portion 35. This makes it possible to prevent a body from being pinched in the back-back space 32 even if the body is inserted into the back-back space 32.

[0052] The bed 1 further comprises a base frame 2 below the mattress 5, the displacement mechanism 10 includes a lifting mechanism 11 that raises and lowers the mattress 5, the gap 30 includes a bottom space 33 that reduces in size as the mattress 5 lowers, and the capacitance sensor 60 is installed on the base frame 2 as a gap defining portion 35. This makes it possible to prevent a body from getting caught in the bottom space 33 even if the body slips into it.

[0053] The capacitance sensor 60 is in the form of a flexible tube, which allows the capacitance sensor 60 to be installed in various locations where pinching is expected, thereby preventing pinching in various locations.

[0054] The pinch detection device 50 further includes a switch 51 interposed in a circuit connecting the power supply unit 25 to an external power supply 90, a circuit connecting the power supply unit 25 to the electric motor 15, or a circuit connecting the operating member 20 to the power supply unit 25, and is configured such that when the capacitance sensor 60 detects the presence of an external power supply 90, the control device 70 disables the electric motor 15 by switching the switch 51 from closed to open. This physically stops the operation of the electric motor 15, ensuring that the electric motor 15 is reliably switched to the disabled state. This improves the reliability of pinch prevention.

[0055] The control device 70 is configured to release the disabled state of the electric motor 15 when a predetermined release condition is met after the electric motor 15 has been disabled, and the release condition is at least one of the following: the capacitance sensor 60 no longer detects the presence of the electric motor 15; a set time has elapsed since the electric motor 15 was disabled; or the release switch 53 of the pinch detection device 50 has been operated. This allows the operating member 20 to be enabled after the risk of pinch occurring has been eliminated.

[0056] The pinch detection device 50 further includes an alarm 52 that is activated when the capacitance sensor 60 detects the presence of an object. This allows the user to be notified of the risk of pinch occurring at an early stage.

[0057] Although the embodiments have been described above, the above configurations can be modified as appropriate within the scope of the present invention.

[0058] 7 and 8 are block diagrams of pinch detection devices 50 according to first and second modifications. As shown in Fig. 7, the power supply unit 25 may be connected to an external power supply 90 without the intervention of the control device 70. In this case, a switch may be provided on the power supply line connecting the power supply unit 25 to the external power supply 90. As shown in Fig. 8, the switch may be provided on the circuit connecting the operating member 20 to the power supply unit 25.

[0059] In the example shown, the capacitance sensor 60 is laid parallel to the outside of the horizontal member 8b of the side fence 8, but the capacitance sensor 60 may also be housed inside the horizontal member 8b. Also, although a tubular capacitance sensor 60 is used, it may be flat (plate-shaped, thin-film-shaped), in which case the surface of the plate should preferably be covered with a resin protective material. Also, the flat capacitance sensor may be attached either inside or outside the side fence 8. Such a flat capacitance sensor 60 may also be installed in a gap determination section 35 other than the side fence 8.

[0060] The displacement mechanism 10 may include a leg-raising mechanism that bends and straightens the legs (the part on the other longitudinal side) of the mattress 5, and the electric motor 15 may include a leg-raising motor that drives the leg-raising mechanism. In this case, the size of the gap defined by the legs of the mattress 5 and the bed frame is variable according to the bending and straightening of the legs of the mattress 5. A capacitance sensor may be set in the part that defines the gap. [Explanation of symbols]

[0061] 1,101 beds 2 base frame 2a Longitudinal frame 3 Caster 4 bed frames 4a Side frame 5 Mattresses 5a back 6 Headboard 7 Footboard 8 side fence 8a outer frame 8b Cross member 9 Electric unit 10 Displacement mechanism 11 Lifting mechanism 12 Back-raising mechanism 15 Electric motor 16 Lifting motor 17 Back-raising motor 20 Operating member 25 Power Supply Unit 30 Gap 31 Side fence gap 32 Dorsal space 33 Bottom space 35 Gap definition section 50 Entrapment detection device 51 Switch 52 Alarm 53 Release switch 60 Capacitive Sensor 60a resin core wire 60b braided wire 60c coated 61 Side fence sensor 62 Back sensor 63 Base Sensor 70 Control device 71 Stop judgment section 90 External power supply

Claims

1. a displacement mechanism that displaces the floor portion; an electric motor that drives the displacement mechanism; a gap defining portion that defines a gap having a size that can be varied in accordance with the displacement of the floor portion; A pinch detection device provided in an electric bed, a capacitance sensor disposed in the gap defining portion to detect the presence of a body in the gap; a controller configured to disable the electric motor when the capacitance sensor detects the presence; A pinch detection device for an electric bed.

2. The electric bed further includes a side rail disposed on a side of the bed portion, The displacement mechanism includes a back-raising mechanism that raises and lowers the back portion of the floor portion, The gap portion includes a gap in the side fence that changes size in a side view according to the contours of the back portion, The capacitance sensor is installed on the side fence as the gap defining portion. The pinch detection device for an electric bed according to claim 1.

3. The displacement mechanism includes a back-raising mechanism that raises and lowers the back portion of the floor portion, The gap portion includes a space behind the back portion, the size of which decreases as the back portion is lowered, The capacitance sensor is installed on the back side of the back portion serving as the gap defining portion. The pinch detection device for an electric bed according to claim 1.

4. The electric bed further includes a base frame below the bed portion, the displacement mechanism includes a lifting mechanism that raises and lowers the floor portion, the gap portion includes a space below the floor portion and inside the base frame, the size of which decreases as the floor portion descends; The capacitance sensor is installed on the base frame as the gap defining portion. The pinch detection device for an electric bed according to claim 1.

5. The capacitance sensor is a flexible tube. The pinch detection device for an electric bed according to any one of claims 1 to 4.

6. The electric bed further comprises an operating member operated by a user, and a power supply unit that operates the electric motor in response to operation of the operating member, the pinch detection device further includes a switch interposed in a circuit connecting the power supply unit to an external power supply, a circuit connecting the power supply unit to the electric motor, or a circuit connecting the operating member to the power supply unit; and when the capacitance sensor detects the presence, the controller is configured to disable the electric motor by switching the switch from closed to open. The pinch detection device for an electric bed according to any one of claims 1 to 4.

7. the control device is configured to cancel the disabled state of the electric motor when a predetermined cancel condition is satisfied after the electric motor is disabled; The release condition is at least one of the following: a condition that the capacitance sensor no longer detects the presence; a condition that a set time has elapsed since the electric motor was put into the inoperable state; and a condition that a release switch provided in the pinch detection device has been operated. The pinch detection device for an electric bed according to any one of claims 1 to 4.

8. further comprising an alarm that is activated when the capacitance sensor detects the presence. The pinch detection device for an electric bed according to any one of claims 1 to 4.

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