JP2013242149A - Bed with load detection function and load detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bed with a load detection function, capable of adding the load detection function by a simple structure while reducing an increase in the number of components.SOLUTION: A bed with a load detection function for detecting a load applied to a bed body by a load detector attached to the bed body and detecting a user's state on a bed surface of the bed body includes: a bed surface formation part; leg parts brought into contact with an installation surface on which the bed body is to be installed; and connection support parts each connecting between the bed surface formation part and the leg part to transmit a load from the bed surface formation part to the leg part. The load detector includes a load cell for measuring deformation generated due to application of the load to the bed body, and the load cell is attached to a portion for receiving the load from the bed formation part side and transmitting the load to the attachment surface side on any one of positions of a load transmission route from the bed surface formation part to the leg part through the connection support part.

Description

  The present invention detects a change in load applied to a bed body by a load detector attached to the bed body, and a bed with a load detection function for detecting the state of a user on the bed surface of the bed body, and the like. The present invention relates to a load detector for adding a load detection function to a bed.

    For example, in beds used in medical institutions, nursing homes, nursing homes, lodging facilities, general homes, etc., changes in the load applied to the bed body are detected, and users (sick people, patients on the bed surface of the bed body) are detected. There has been proposed a method for detecting the state of a caregiver, an infant, a healthy person, or the like (such as entering a floor, getting out of bed, lying in bed, body movement, etc.) (for example, see Patent Documents 1 to 3).

    Specifically, in Patent Document 1 below, a load sensor is disposed between a leg portion provided on the bed main body and an installation surface (floor surface or the like) on which the bed main body is installed. A method for detecting a person's presence based on an electrical signal is disclosed. Further, the load sensor is formed with a slope portion for guiding a caster provided on the leg portion of the bed main body from the installation surface of the bed main body onto the load receiving portion of the load sensor.

  On the other hand, Patent Literature 2 below discloses a method of detecting a load applied to a bed body by providing a load detector in a space between the bed body and an installation surface on which the bed body is installed. . The load detector is provided with a means for lifting the bed.

  On the other hand, Patent Document 3 below discloses a structure in which a bed frame has a double structure and a load cell (load detector) is incorporated therebetween.

  As a detector (load cell) used for detecting the load of this kind of bed body, a strain is generated in the strain generating body by the load, and the degree of the strain is electrically or optically measured by the strain sensor, and further magnetically. What is detected in the above is widely used. The most widely used detection element of such a strain sensor is a strain gauge (strain gauge) whose electric resistance changes due to strain.

  By the way, various types of load cells using strain gauges are known. As typical examples, for example, as shown in FIG. 31, a cantilever type cantilever type incorporating a Roverval mechanism is used. It is known (see, for example, Patent Document 4). In this type of load cell, a square bar or a thick plate made of aluminum alloy, stainless steel, or the like is used as a strain body 300, and a Roverval mechanism 302 is formed in an intermediate portion in the length direction of the strain body 300. One or more strain gauges 304A, 304B constituting the strain sensor 304 are attached to the outer surface positions of the strain generating bodies corresponding to the enlarged hole portions 303A, 303B at both ends of the long hole 303 constituting the Roverval mechanism 302. Then, one end 306A of the strain generating body 300 is fixed to the fixing portion 308 (that is, cantilevered) so that the length direction is horizontal and the attaching surfaces of the strain gauges 304A and 304B are the upper surface or the lower surface. And a load W is applied to the other end 306B from the outside.

  In this type of cantilever type load cell, when a load W is applied to the tip of the cantilever 300 supported by the cantilever, the strain 300 is elastically moved in the direction in which the tip is lowered. As a result of bending deformation, tensile strain or compressive strain is generated on the upper and lower surfaces of the strain generating body 300, particularly in the vicinity of the Roverval mechanism 302, and the strain is detected by the strain gauges 304A and 304B. And since the magnitude | size of the distortion respond | corresponds to the applied load, it becomes possible to detect the magnitude | size of the load W as a result. For example, as a load detector for a bed, Patent Document 2 and Patent Document 3 show that such a cantilever type load cell is used.

  On the other hand, for example, as shown in FIG. 32, there is also known a double-supported beam type load cell that supports both of the strain generating bodies 300 (see, for example, Patent Document 5). In this double-supported beam type load cell, both ends 306A and 306B in the length direction of the strain body 300 made of a square bar or a thick plate made of aluminum alloy or stainless steel are fixed to fixing portions 308A and 308B, respectively ( In other words, both ends are supported), and the load W is applied to the central portion 310 in the length direction of the strain generating body 300 from the outside. In addition, it is normal to form the robotic mechanisms 302A and 302B on both sides of the central portion 310 of the strain generating body 300, and in this case, the strain gauges 304A to 304D of the strain sensor are formed on the upper surface of the strain generating body 300. Or it is normal to stick to the position corresponding to each edge part of the said robotic mechanism 302A, 302B in a lower surface.

  In this type of both-end supported beam type load cell, when a load W is applied to the center portion of the strain-generating body 300 supported by both ends, the strain-generating body 300 is elastically curved in a direction in which the center portion is lowered. Bending and deforming, tensile strain or compressive strain is generated between the central portion and both end portions of the strain generating body 300 on the upper surface and the lower surface, particularly in the vicinity of the Roverval mechanism 302, and the strain is detected by the strain gauges 304A to 304D. As a result, the magnitude of the load W can be detected.

  In addition, as a principle similar to the double-supported beam type load cell shown in FIG. 32, a periphery of a flat plate-like strain generating body such as a horizontal disk is supported, and the center of the flat plate-shaped strain generating body is supported. A load cell of a so-called diaphragm type that detects a strain generated between the central portion and the peripheral portion by applying a load W is also known. As a load detector for a bed, in Patent Document 1, It is shown that such a flat load cell is used.

JP 2000-105884 A JP 2008-304397 A JP 2007-256074 A JP-A-10-221183 Japanese Patent Laid-Open No. 10-2812

  However, in the invention described in Patent Document 1, when the load of the bed main body is detected using the load sensor, the caster provided on the leg portion of the bed is moved to the vicinity of the front side of the slope portion of the load sensor. After passing over the slope portion, it must be placed on the load receiving portion of the load sensor, which is very troublesome.

  On the other hand, in the invention described in Patent Document 2, for example, when the bed main body is installed along the wall, the installer cannot enter between the bed main body and the wall. It becomes very difficult to arrange in a space between the installation surface.

  On the other hand, in the invention described in Patent Document 3, although the load detector is incorporated in the bed main body in advance, the bed main body must be designed in accordance with the load detector, and a new part for that purpose is required. . For this reason, it becomes very expensive as a bed with a load detection function. Furthermore, weight reduction becomes difficult due to an increase in the number of parts.

  Further, when the conventional load cell using the cantilever (cantilever) type strain sensor shown in FIG. 31 is applied to the bed body, one end of the strain body is fixed to a fixed portion of the bed body, and the strain body Since the load W is applied to the other end of the elastic body in a direction perpendicular to the length direction of the strain generating body, when the strength of the strain generating body is low, the strain generating body may be broken or repeatedly There is a problem that the strained body is easily damaged by a load. In particular, in order to increase the load detection accuracy, in order to increase the amount of strain generated by the applied load, the distance between the support position (fulcrum) with respect to the fixed part and the position where the load W is applied (force point), that is, strain generation If the substantial length of the body is increased, the strain generating body will be more easily broken and broken. On the other hand, if the rigidity of the strain generating body is increased in order to prevent breakage or breakage due to such an excessive load or repeated load, the generation of strain when the load is applied is reduced, and therefore the load detection accuracy is lowered. . Furthermore, since the fulcrum position is biased laterally by the substantial length of the strain generating body with respect to the direction line to which the load W is applied, there is a problem that it is difficult to install in a narrow place. And since it is a cantilever system, it is necessary to attach the fulcrum part firmly to the fixed position of the bed body, so when installing the load cell in the existing bed body, There is also a problem that the bed body must be processed again.

On the other hand, when the conventional double-end beam type load cell as shown in FIG. 32 is applied, both ends of the strain-generating body are supported. Therefore, compared with the cantilever type load cell shown in FIG. Although the risk of breakage and fatigue failure due to a heavy load is small, on the other hand, deformation of the strain generating body is less than that of the cantilever method, and there is a risk that strain measurement with high accuracy may be difficult. Moreover, since the fulcrum is located on both sides of the direction line to which the load W is applied, there is a problem that it is difficult to install in a narrower place than the cantilever system.
In addition, the diaphragm type flat plate load cell has the same problem as the above-mentioned doubly supported beam type.

  The present invention has been proposed in view of such a conventional situation, and can easily and easily add a load detection function to the bed body while suppressing an increase in the number of parts, and is durable. To provide a bed with a load detection function that is superior and has high load detection accuracy, and a load detector that can be easily incorporated into the bed body in order to add such a load detection function to an existing bed. Objective.

The bed with a load detection function according to the basic aspect of the present invention (first aspect)
The load detector attached to the bed body detects a change in the load applied to the bed body, and a bed with a load detection function for detecting the state of the user on the bed surface of the bed body,
The bed body includes a bed surface forming portion that forms the bed surface, legs that are in contact with an installation surface on which the bed body is to be installed, and the bed surface so that the bed surface forming portion is located above the installation surface. It is configured to have a connection support part that connects the forming part and the leg part and transmits the load from the bed surface forming part toward the leg part,
The load detector has a load cell that measures strain generated by applying a load to the bed body,
The load cell includes a base body to which a load is applied from the bed surface forming portion side, and a strain sensor attached to the base body.
The base body includes a load receiving beam portion having a load receiving region and a pair of fulcrum receiving regions, a pair of operating arm portions projecting from different positions in the load receiving beam portion, and a tip side portion of the pair of operating arm portions The load receiving beam portion, the pair of operating arm portions and the connecting portion are configured so as to continuously surround the hollow portion as a whole,
The load receiving area is formed at a position corresponding to a reference plane crossing a straight line connecting the pair of fulcrum receiving areas in the middle of the pair of fulcrum receiving areas, and the load receiving area is along the reference plane Configured to receive loads applied in the direction,
Further, one of the pair of operating arm portions protrudes from a side on which one of the pair of fulcrum receiving regions is located with respect to the reference plane in the load receiving beam portion, and The other is formed so as to protrude from the side where the other fulcrum receiving region of the pair of fulcrum receiving regions is located with respect to the reference surface in the load receiving beam portion,
The strain sensor is attached to at least one of the pair of operating arm portions, and applies the load along the reference plane to the load receiving area while supporting the pair of fulcrum receiving areas. At least one of the actuating arm portions is elastically deformed, and the strain sensor is configured to detect the strain of the elastic deformation,
In response to a load from the bed surface forming portion side at any part of the load transmission path from the bed surface forming portion to the leg portion through the connection support portion in the bed body, the load is transmitted to the installation surface side. The base of the load sensor is provided at the site.
Here, the “middle of the pair of fulcrum receiving areas” may be between the pair of fulcrum receiving areas, and is not limited to the center of the pair of fulcrum receiving areas.
Further, the “reference plane” is a virtual plane that is arranged in such a direction that a straight line connecting the pair of fulcrum receiving areas penetrates between the pair of fulcrum receiving areas. However, the present invention is not limited to the case of arranging in an orthogonal direction.
In other words, the “load transmission path” is a structural member that transmits the load applied to the bed surface forming part to the leg part in contact with the ground contact surface, or extends from the bed surface forming part in the leg direction to form the bed surface forming part. A structural member that supports a load applied to the portion, or a structural member that supports a load applied to the bed surface forming portion to the leg portion.
The “hollow part” is a hollow part formed by a load receiving beam part, a pair of operating arm parts, a connecting part, and the like.

  In such a bed with a load detection function of the first aspect, if the fulcrum receiving area in the base of the load cell is supported by the member of the bed main body, the load receiving beam portion functions as a so-called doubly supported beam. Therefore, if a load is applied to the load receiving area of the load receiving beam portion along the reference plane, a curved micro-deformation deformation (in the direction of projecting along the reference plane around the load receiving beam portion around the portion) ( Elastic deformation). In other words, this micro-deformation deformation is caused to slightly incline with respect to the plane orthogonal to the reference plane at each of the left and right side portions (portions close to the fulcrum receiving area) with respect to the reference plane in the load receiving beam portion. Along with this, a force that inclines in the direction of increasing the distance between the tip portions acts on the pair of operating arm portions protruding from the position between the reference surface and the fulcrum receiving region in the load receiving beam portion. Since the portion on the distal end side of the actuating arm portion is constrained by the connecting portion, the force acts to increase the distance between the intermediate portions in the length direction of the pair of actuating arm portions. . Accordingly, at least one of the pair of operating arm portions is minutely deformed so that an intermediate portion in the length direction protrudes in a direction away from the reference surface. Therefore, a surface of the at least one working arm portion facing the hollow portion (a surface facing the reference surface: an inner surface) and a surface facing the outer side with respect to the hollow portion (a surface facing the reference surface outward): A strain (tensile strain or compressive strain) is generated on the outer surface, and the strain is detected by a strain sensor. Here, since the distortion of the operating arm portion is caused by the strain of the load receiving beam portion, as a result, the strain of the load receiving beam portion, and consequently the load applied to the load receiving beam portion (the load of the bed body) Is detected.

  In the bed with a load detection function of the first aspect, the length from the load receiving beam portion to the connecting portion in the operating arm portion of the load cell base is set to the distance between the pair of fulcrum receiving areas of the load receiving beam portion. Thus, by appropriately setting the rigidity of the operating arm portion and appropriately adjusting the rigidity of the operating arm portion, the strain of the operating arm portion can be made larger than the strain of the load receiving beam portion when a load is applied. That is, in that case, the strain of the load receiving beam portion is amplified by the operating arm portion. Then, by detecting the amplified strain by the strain sensor, it is possible to detect the load with higher accuracy than in the case of directly detecting the strain of the load receiving beam portion.

  Here, as described above, the length to the connecting portion of the operating arm portion required to amplify the distortion by the operating arm portion depends on the rigidity of the operating arm portion depending on the material, shape, cross-sectional area, etc. of the operating arm portion. Since it is different, it cannot be specified unconditionally, but assuming that the rigidity of the operating arm is equivalent to that of the load receiving beam, the length of the operating arm is a pair of fulcrums of the load receiving beam. If the distance is larger than the distance between the receiving regions, it is considered that the above distortion amplification effect can be exhibited. However, in practice, by adjusting the shape and cross-sectional area of the operating arm so that its rigidity is lower than that of the load receiving beam, the length of the operating arm is determined by the pair of fulcrums of the load receiving beam. Even when the distance is smaller than the distance between the receiving regions, the above distortion amplification effect can be exhibited. Further, the length and length of the operating arm are made larger than the distance between the pair of fulcrum receiving areas of the load receiving beam, and at the same time, the shape and cut-off are made so that the rigidity of the operating arm is lower than that of the load receiving beam. If the area or the like is adjusted, the strain amplification effect can be further increased, and the load can be detected with higher accuracy.

  In addition, since the load of the bed main body is not directly applied to the operating arm portion, even if its rigidity is significantly smaller than that of the load receiving beam portion, there is little risk of breakage or fatigue failure due to load application. Therefore, it is practically possible to increase the distortion amplification effect by lowering the rigidity of the operating arm.

  On the other hand, although the load receiving beam part is a part that directly receives the load of the bed body, the load cell used in the present invention does not directly detect the strain generated in the load receiving beam part. When the strain amplification effect due to is obtained, the strain amount of the load receiving beam portion due to the load of the bed main body may be slight. Accordingly, it is possible to increase the rigidity of the load receiving beam portion itself and reduce the risk of breakage of the load receiving beam portion due to an excessive load and fatigue failure due to repeated loads.

  Further, as described above, the strain amount of the load receiving beam portion due to the load of the bed main body may be small, so that the distance between the pair of fulcrum receiving areas of the load receiving beam portion is highly accurate. There is no need to increase the size. That is, it is possible to reduce the length of the load receiving beam portion and reduce the dimension in a plane perpendicular to the direction in which the load is applied. As a result, the load detector can be arranged in a narrow part of the bed body.

  Furthermore, since the load receiving beam portion is supported as a doubly supported beam by a pair of fulcrum receiving areas, the important point is that the fulcrum receiving area is supported so as not to be detached from the member fixed to the bed body. good. Therefore, it is not necessary to firmly fix to the support member fixed to the bed body in the fulcrum receiving area, so when installing the load detector, processing or welding to fix to the bed body member, It is not necessary to use a fastening member such as a nut, and it can be easily installed on an existing bed body.

The bed with a load detection function according to the second aspect of the present invention is the bed with a load detection function according to the first aspect.
Each of the load receiving regions in the load cell is configured by a surface in contact with a load application member to which a load from the bed surface forming portion is guided.

Moreover, the bed with a load detection function according to the third aspect of the present invention is the bed with a load detection function according to the first or second aspect,
The strain sensor is attached to one or both of a surface facing the outside and a surface facing the inner side among the surfaces of the at least one operating arm portion. It is what.

  The load receiving beam portion is bent and deformed by the load of the bed body, and at the same time, the distortion when at least one of the operating arm portions is deformed in the direction in which the interval between the pair of operating arm portions is expanded is caused in the operating arm portion. Out of each surface, the outer surface and the inner surface with respect to the hollow portion appear significantly and stably as tensile strain or compressive strain. Therefore, as defined in the third aspect, By attaching the strain sensor to one or both of the surface and the inner surface, the strain of the operating arm can be reliably detected.

The bed with a load detection function according to the fourth aspect of the present invention is the bed with a load detection function according to the third aspect.
One working arm of the pair of working arms is made to be less rigid than the other working arm, and the strain sensor is attached to the one working arm. It is a feature.
In the fourth aspect, when the load of the bed main body is applied and the load receiving beam portion is bent and deformed, and the operating arm portion is deformed accordingly, the one operating arm portion on the side having a lower rigidity is The deformation is greater than that of the other operating arm, and the amount of distortion of the one operating arm is greater than the amount of distortion of the other operating arm. In some cases, only one of the working arm portions is substantially deformed, the other working arm portion is very little deformed, and a large distortion occurs only in the one working arm portion. In any case, the deformation of the working arm portion accompanying the bending deformation of the load receiving beam portion is concentrated on one working arm portion, and as a result, the strain amount of the one working arm portion is reduced to both working arms. It becomes larger than the case where distortion occurs evenly in the part. Therefore, it is possible to detect the load with higher accuracy by detecting the strain on the one operating arm side.

The bed with a load detection function according to the fifth aspect of the present invention is the bed with a load detection function according to the fourth aspect.
When a concave portion is formed on the inner and / or outer surface facing the hollow portion of one of the pair of operating arm portions and the one operating arm portion is elastically deformed, the operation is performed. The arm portion is configured to amplify the strain corresponding to the concave portion, and the strain sensor is attached to the portion.

  In the fifth aspect, since the width of the inner and outer directions of the working arm portion is locally smaller at the position of the recess in the one working arm portion, the portion is locally smaller than the other portion. The rigidity is small, so that the deformation of the part becomes large even when the load is the same (the distortion is amplified), and the load can be detected with higher accuracy by detecting the distortion of the part.

Moreover, the bed with a load detection function according to the sixth aspect of the present invention is the bed with a load detection function according to the fourth aspect.
Two or more concave portions are formed at intervals in the length direction of the working arm portion on one of the pair of working arm portions on the inner and / or outer surface facing the hollow portion. In addition, when the operating arm portion is elastically deformed, the strain of the portion corresponding to each of the two or more recesses in the operating arm portion is configured to be amplified,
In addition, the strain sensor is composed of one or more strain detection elements, and at least one of the one or more strain detection elements corresponds to at least one of the two or more recesses. It is attached to the site | part which performs.

  In this sixth aspect, since two or more concave portions are formed on the inner surface facing the hollow portion with an interval in the protruding length direction of the operating arm portion, two concave portions are formed adjacent to each other. About the part, it has the same shape as the half on one side of the glasses-type Roverval mechanism. Therefore, when a load is applied to the load receiving beam portion 7 and the operating arm portion is deformed, distortion is caused at a position corresponding to the outer side of each concave portion, as in the case of providing a glasses-type robust mechanism. It can be generated intensively.

The bed with a load detection function according to the seventh aspect of the present invention is the bed with a load detection function according to the sixth aspect.
The strain sensor is composed of two or more strain detection elements, and at least one of the two or more strain detection elements is one of the two or more adjacent recesses. And at least one other strain detection element is attached to a portion corresponding to the other of the two or more adjacent recesses.

  In such a seventh aspect, as described with respect to the sixth aspect, the portion where two concave portions are formed adjacent to each other in the length direction of one of the operating arm portions is one side of the glasses-type Roverval mechanism. Since the shape is similar to the half, when a load is applied to the load receiving beam portion 7 and the operating arm portion is deformed, distortion is intensively generated at a position corresponding to the outside of each concave portion. Can be made. At this time, a strain in the opposite direction with respect to the tensile strain / compression strain can be generated between the portion where one of the two adjacent recesses is formed and the portion where the other recess is formed. Therefore, a portion where tensile strain is generated and a portion where compressive strain is generated are close to each other on the same surface side of the operating arm portion. Therefore, when a strain sensor composed of two or more strain detection elements (for example, strain gauges) is used, the strain detection element on which tensile strain acts and the strain detection element on which compression strain acts can be arranged close to each other. Therefore, the wiring between the strain detection elements and the handling of the lead wire to the external device are facilitated.

Moreover, the bed with a load detection function according to the eighth aspect of the present invention is the bed with a load detection function according to any one of the first to seventh aspects.
One of the pair of actuating arm parts is formed with a Roverval mechanism, and when the one actuating arm part is elastically deformed, distortion of the actuating arm part is amplified by the Roverval mechanism. And a strain sensor is attached to the one working arm.

The bed with a load detection function according to the ninth aspect of the present invention is the bed with a load detection function according to any one of the first to eighth aspects.
The pair of fulcrum receiving areas in the load cell are each configured by a surface supported in contact with a fixed part in the bed body.

Furthermore, the bed with a load detection function according to the tenth aspect of the present invention is the bed with a load detection function according to any one of the first to eighth aspects,
The pair of fulcrum receiving areas in the load cell are respectively fitted into fixed portions in the bed main body.

  Furthermore, the bed with a load detection function according to the eleventh aspect of the present invention is the bed with a load detection function according to any one of the first to eighth aspects, wherein the pair of fulcrum receiving areas in the load cell are fixed in the bed body, respectively. It is characterized by comprising a mounting hole for supporting the substrate at the site.

In these ninth to eleventh aspects, a preferable configuration for supporting the pair of fulcrum receiving areas in the base body of the load cell is defined. However, in any aspect, the load receiving beam part is supported on both ends. Thus, load detection can be performed as described above. Here, since the pair of fulcrum receiving areas do not need to be firmly fixed to the bed body member as already described, for example, in the ninth aspect, the surface of the fulcrum receiving area is in contact with the bed body member. It is only necessary to mount it. In the tenth aspect, when the fulcrum receiving area is fitted into the fixed part of the bed main body, it is not necessary to fit closely. Furthermore, in the eleventh aspect, it is only necessary to insert a pin (shaft) on the bed main body side into the attachment hole, and there is no need for screwing or the like.
In some cases, however, the fulcrum receiving area is allowed to be firmly fixed to the member of the bed main body by screwing or welding.

A bed with a load detection function according to a twelfth aspect of the present invention is the bed with a load detection function according to any one of the first to eleventh aspects.
The base body of the load cell is interposed in the middle of the connection support portion in the bed body.

A bed with a load detection function according to a thirteenth aspect of the present invention is the bed with a load detection function according to the twelfth aspect.
The connection support portion includes an elevating link mechanism that elevates and lowers the bed surface forming portion, and a base of the load cell is incorporated in the elevating link mechanism.

A bed with a load detection function according to a fourteenth aspect of the present invention is the bed with a load detection function according to the thirteenth aspect.
In addition to the elevating link mechanism, the connection support portion includes a lower frame supported via the legs above the installation surface,
The elevating link mechanism has at least a first arm and a second arm as an arm connecting the bed surface forming portion and the lower arm, and the first arm is configured to have the bed surface. It is connected to the forming portion side, the second arm is connected to the lower frame side, and the base of the load cell is interposed between the bed surface forming portion and the lower arm. To do.

The bed with a load detection function according to the fifteenth aspect of the present invention is the bed with a load detection function according to the fourteenth aspect,
The bed surface forming part has a bed and an upper frame that supports the bed,
The lifting link mechanism includes at least a first arm and a second arm as an arm connecting the upper frame and the lower arm, and the first arm is provided on the upper frame. The second arm is connected to the lower frame side, and the base body of the load cell is interposed between the upper frame and the lower arm.

The bed with a load detection function according to the sixteenth aspect of the present invention is the bed with a load detection function according to the fifteenth aspect.
One of the upper arm and the lower arm is provided with a support shaft at the end of the load cell on the side where the base is located, and either one of the load receiving part and the load transmitting part on the base A bearing portion for receiving the support shaft is formed on one side.

A bed with a load detection function according to a seventeenth aspect of the present invention is the bed with a load detection function according to the sixteenth aspect.
The load transmitting portion in the base of the load cell is an attachment portion attached to the other arm of the upper arm and the lower arm.

A bed with a load detection function according to an eighteenth aspect of the present invention is the bed with a load detection function according to the seventeenth aspect,
A hollow cylinder portion is formed at an end of the other arm on the substrate side, and the attachment portion of the substrate is inserted into the hollow cylinder portion, and the attachment portion is fixed to the hollow cylinder portion. It is characterized by being.

A bed with a load detection function according to a nineteenth aspect of the present invention is the bed with a load detection function according to any one of the first to eleventh aspects.
A base of the load cell is interposed between the bed surface forming portion and the connection support portion.

A bed with a load detection function according to a twentieth aspect of the present invention is the bed with a load detection function according to any one of the first to eleventh aspects.
A base of the load cell is interposed between the connection support portion and the leg portion.

A bed with a load detection function according to a twenty-first aspect of the present invention is the bed with a load detection function according to any one of the first to eleventh aspects.
The load cell base is incorporated in the leg portion.

A bed load detector according to the twenty-second aspect of the present invention is also provided.
A bed surface forming portion that forms a bed surface, a leg portion that is in contact with an installation surface on which the bed body is to be installed, and a bed surface forming portion and a leg portion so that the bed surface forming portion is located above the installation surface. Measuring the change in the load applied to the bed body by attaching to a bed body having a connection support part that connects between and transmits the load from the bed surface forming part toward the leg part, In the load detector for detecting the state of the user on the bed surface of the bed body,
A load cell having a base that receives a load from the bed surface forming portion side and a strain sensor attached to the base to detect strain of the base;
The base body includes a load receiving beam portion having a load receiving region and a pair of fulcrum receiving regions, a pair of operating arm portions projecting from different positions in the load receiving beam portion, and a tip side portion of the pair of operating arm portions The load receiving beam portion, the pair of operating arm portions and the connecting portion are configured so as to continuously surround the hollow portion as a whole,
The load receiving area is formed at a position corresponding to a reference plane crossing a straight line connecting the pair of fulcrum receiving areas in the middle of the pair of fulcrum receiving areas, and the load receiving area is along the reference plane Further, one of the pair of operating arm portions protrudes from a side where one of the pair of fulcrum receiving regions is located with respect to the reference plane in the load receiving beam portion. In addition, the other of the pair of operating arm portions is formed so as to protrude from a side where the other fulcrum receiving region of the pair of fulcrum receiving regions is located with respect to the reference plane in the load receiving beam portion. And
The strain sensor is attached to at least one of the pair of operating arm portions, and applies a load along the reference plane to the load receiving region in a state where the pair of fulcrum receiving regions are supported. At least one of the operating arm portions is elastically deformed, and the strain sensor is configured to detect strain of the elastic deformation,
In addition, the load is received from the bed surface forming portion side at any part of the load transmission path from the bed surface forming portion to the legs through the connection support portion in the bed body, and the load is transferred to the installation surface side. The base body is configured to be attached to the transmitting portion so as to be exchangeable with parts of the bed main body.

  According to the present invention, it is possible to add a load detection function with a simple structure while suppressing an increase in the number of parts, and at the same time, it is possible to detect a load with high accuracy while ensuring the durability of the load detector. Thus, it is possible to provide a bed with a load detection function and a load detector that can be separately incorporated into the bed main body in order to add such a load detection function to an existing bed.

It is a front view which shows an example of the fundamental structure of the load cell in the load detector used for the bed with a load detection function of this invention. It is a longitudinal cross-sectional view in the II-II line in FIG. It is a circuit diagram which shows the Wheatstone bridge circuit used for the strain sensor of the load cell shown in FIG. It is a front view which shows the state by which the load was applied to the load cell shown in FIG. It is a front view which shows the other example of the fundamental structure of the load cell in the load detector used for the bed with a load detection function of this invention. It is a front view which shows another example of the fundamental structure of the load cell in the load detector used for the bed with a load detection function of this invention. It is a front view which shows another example of the fundamental structure of the load cell in the load detector used for the bed with a load detection function of this invention. FIG. 8 is a front view showing a state in which a load is applied to the load cell shown in FIG. 7. It is a front view which shows the example which actualized the load cell in the load detector used for the bed with a load detection function of this invention more. FIG. 10 is a left side view of the load cell shown in FIG. 9. FIG. 10 is a right side view of the load cell shown in FIG. 9. It is a longitudinal cross-sectional view in the XII-XII line | wire in FIG. It is a perspective view from diagonally downward about the load cell shown in FIG. FIG. 10 is a front view showing a state in which a load is applied to the load detector shown in FIG. 9. It is a front view which shows an example of the support aspect of the load cell used for the bed with a load detection function of this invention. It is a front view which shows the other example of the support aspect of the load cell used for the bed with a load detection function of this invention. It is a front view which shows an example of the usage condition of the load cell used for the bed with a load detection function of this invention. It is a front view which shows the other example of the usage condition of the load cell used for the bed with a load detection function of this invention. It is a front view which shows another example of the usage condition of the load cell used for the bed with a load detection function of this invention. It is a front view which shows another example which actualized more the load cell used for the bed with a load detection function of this invention. FIG. 21 is a front view showing a state in which a load is applied to the load cell shown in FIG. 20. It is a side view which shows an example of the bed with a load detection function to which this invention is applied. (A) is the principal part side view of the bed main body which shows the state which the bedplate fell by the raising / lowering link mechanism, (b) is the principal part side view of the bed main body which shows the state which the bedboard rose by the raising / lowering link mechanism. is there. (A) is the side view which expanded the principal part of the raising / lowering link mechanism in which the load cell was integrated, (b) is the front view which expanded the principal part of the raising / lowering link mechanism in which the load cell was incorporated. It is a side view which expands the principal part of the other example of the raising / lowering link mechanism in which the load cell was integrated, and shows it according to Fig.24 (a). It is a side view which expands and shows the principal part of the further another example of the raising / lowering link mechanism in which the load cell was integrated. It is a side view which shows the other example of the bed with a load detection function to which this invention is applied. It is a vertical side view which expands and shows the principal part (part in which the load cell was integrated) of the bed with a load detection function in FIG. It is a side view which shows the further another example of the bed with a load detection function to which this invention is applied. It is a vertical side view which expands and shows the principal part (part in which the load cell was integrated) of the bed with a load detection function in FIG. It is an approximate solution figure showing an example of the conventional load detector. It is a schematic diagram which shows another example of the conventional load detector.

  Hereinafter, embodiments of a bed with a load detection function and a load detector according to the present invention will be described in detail with reference to the drawings. In addition, the example shown below is only an illustration and this invention is not limited to these examples.

  First, a load detector used for a bed with a load detection function of the present invention will be described in order from the principle to a specific configuration with reference to FIGS.

  FIG. 1 and FIG. 2 are diagrams showing a principle configuration of a load detector used in a bed with a load detection function of the present invention, and FIG. 3 is a Wheatstone bridge circuit used for a strain sensor of the load detector. Further, FIG. 4 is a view corresponding to FIG. 1 showing a situation (a situation where a load is applied) when the load detector having the above-described principle configuration is used.

1 and 2, the load detector 1 includes a load cell 2 including a base 3 to which a load to be detected is applied and a strain sensor 5 attached to the base 3.
The material of the substrate 3 is not particularly limited as long as it is a material that generates elastic strain due to an applied load and has a strength that can withstand the load. Usually, a metal material such as an aluminum alloy or stainless steel is used. Used.
In the example shown in the figure, the substrate 3 is made of a thick plate having a certain thickness T, and a substantially rectangular hollow portion (window portion) 17 is formed in the central portion when viewed in a cross section orthogonal to the thickness direction. As a whole, the shape is a vertically long, substantially rectangular shape. However, the base 3 is not a complete long rectangle, but the upper short side (the load receiving beam portion 7) of the two sides corresponding to the short sides of the long rectangle (the load receiving beam portion 7 and the connecting portion 9 described later) is the upper side. The both end portions are formed so as to protrude left and right from two sides (a pair of operating arm portions 11A and 11B described later) corresponding to the long sides of the long rectangle. The position of the hollow portion (window portion) 17 is not limited to the central portion, and there is no limitation as long as it is a position where the effects of the present invention can be exhibited. In addition, the shape is not limited to a rectangular shape including an oblong shape, and is not limited as long as the effect of the present invention can be exhibited. For example, a shape including a curve such as an ellipse or an ellipse may be used. . The hollow portion (window portion) 17 shown in the figure is a portion surrounded by the load receiving beam portion, the operating arm portion, and the connecting portion.
The upper side of the two short sides of the long rectangle constituting the base body 3 is a load receiving beam portion 7, and a concave portion (13) is formed on the upper surface of the central portion in the length direction. The recessed portion is a load receiving region 13 that receives a load to be detected. Further, horizontal step surfaces (15A, 15B) are formed on the lower surfaces of both end portions in the length direction of the load receiving beam portion 7 (both end portions protruding to the left and right), and the step surfaces use the region as a fulcrum. The fulcrum receiving areas 15A and 15B for supporting the base 3 are used. The load receiving area 13 may be a planar area that does not give a shape such as a depression.
The fulcrum receiving areas (step surfaces) 15A and 15B are placed on the upper surfaces of the externally supported support members 19A and 19B, and an external load is applied to the load receiving area 13 by, for example, a vertical bar-shaped load applying member 21. It is done.

On the other hand, the two parallel sides corresponding to the long sides of the long rectangle constituting the base 3 of the load cell 2 are the operating arm portions 11A and 11B. In this example, the actuating arm portions 11A and 11B are moved downward (ie, the load receiving beam portion 7 with respect to the center position O (the center of the load receiving region 13) O in the length direction of the load receiving beam portion 7 as a reference. Are formed in parallel so as to project in the direction perpendicular to the length direction of the first arm 11A and the lower end portion of the operating arm portions 11A and 11B (the lowermost end portion in the examples of FIGS. 1 and 2). They are connected by a connecting portion 9 corresponding to the lower side (lower side) of the lower side of the rectangle.
In this manner, the base body 3 has the load receiving beam portion 7, the pair of operating arm portions 11 </ b> A and 11 </ b> B, and the connecting portion 9 as a whole as a continuous substantially rectangular hollow portion (window portion) 17. It has a surrounding structure.

  Then, either one or both of the operating arm portions 11A and 11B (only the left operating arm portion 11A in the illustrated example) is on the outer surface side near the center in the length direction (facing outward with respect to the hollow portion 17). On the surface), the strain sensor 5 is adhered. This strain sensor 5 uses, for example, four strain gauges R1, R2, R3, and R4 whose electric resistance changes due to strain as the strain detection elements, and the four strain gauges (strain detection elements) R1, R2, and R3. , R4 may be configured in a Wheatstone bridge circuit 23 as shown in FIG. 3, for example. Of these strain gauges R1 to R4, R1 and R3 are attached to a substantially central portion in the length direction of the operating arm portion 11A or a position slightly below it, and the remaining R2 and R4 are connected to the connecting portion 9. It is attached at a position close to.

  In the basic body 3 of the load cell 2 having the principle configuration shown in FIGS. 1 to 3, it passes through the center position O in the length direction of the load receiving beam portion 7, and the length direction of the load receiving beam portion 7. If the plane orthogonal to the reference plane P is used, the load receiving region 13 (recessed portion) passes through the reference plane P, and one of the operating arm portions 11A and 11B of the pair of operating arm portions 11A and 11B is connected to the load receiving beam portion 7. And the other operating arm so as to protrude in parallel with the reference plane P from the side where one of the fulcrum receiving areas 15A, 15B of the pair of fulcrum receiving areas (step surfaces) 15A, 15B is located. The part 11B is formed so as to protrude in parallel with the reference plane P from the side where the other fulcrum receiving area 15B is located with respect to the reference plane P in the load receiving beam section 7.

  FIG. 4 shows a situation when a load W is applied from the outside in the load cell 2 of the load detector 1 having the principle configuration shown in FIGS. 1 and 2 as described above. Here, the base 3 has fulcrum receiving regions (step surfaces) 15A and 15B on the lower surface side at both ends in the length direction of the load receiving beam portion 7, and the outside of the bed main body (as will be described later in the present invention). The load receiving beam portion 7 is supported in a so-called doubly supported beam state so that the length direction of the load receiving beam portion 7 is horizontal. The external load (the load from the bed surface forming portion in the bed main body in the present invention) W is, for example, a load receiving region on the upper surface of the central portion in the length direction of the load receiving beam portion 7 by the load applying member 21 having a vertical bar shape. 13 (recessed portion) is added vertically (thus along the reference plane P). The vertical rod-shaped load application member 21 is a member constituting a load transmission path.

When a load W is applied in the vertical direction from the load applying member 21 to the load receiving region 13 near the center of the load receiving beam portion 7, the load receiving beam portion 7 is deformed by a small amount of deflection (in the direction in which the central portion projects downward). Elastic deformation). Due to this minute deformation, in the region on the left side with respect to the reference plane P in the load receiving beam portion 7, the portion closer to the central portion is slightly inclined in the downward direction, and in the region on the right side with respect to the reference plane P, the center is also the same. Slightly inclines in the direction in which the part closer to the part goes down. Along with the bending deformation of the load receiving beam portion 7, the pair of operating arm portions 11A and 11B protruding downward from the left and right positions with respect to the reference plane P in the load receiving beam portion 7 are provided at their tip portions ( Although the force which enlarges the distance between lower end part) acts, since the distance between the front-end | tip parts (lower end part) of the right and left operating arm parts 11A and 11B is restrained by the connection part 9, an operating arm The portions 11A and 11B are slightly deformed in the direction in which the central portion in the length direction protrudes left and right. Therefore, tensile strain is generated on the outer surface side (surface facing outward with respect to the reference surface P) near the central portion in the length direction of the operating arm portions 11A and 11B, and the tensile strain is the strain gauge R1 of the strain sensor 5. Acts on R3. On the other hand, compressive strain is generated outside the portions of the operating arm portions 11 </ b> A and 11 </ b> B close to the connecting portion 9, and the compressive strain acts on the strain gauges R <b> 2 and R <b> 4 of the strain sensor 5. Therefore, for example, if the Wheatstone bridge circuit 23 is assembled by the strain gauges R1 to R4 as shown in FIG. 3, the potential difference due to the tensile strain and the compressive strain of the operating arm portion 11A is output as a load signal. Here, since the distortion of the operating arm portion 11A is caused by the distortion of the load receiving beam portion 7, as a result, the distortion of the load receiving beam portion 7 and consequently the load applied to the load receiving beam portion 7 is detected. It will be done.
The elastic deformation occurs, for example, in such a manner that the load receiving beam part is deformed minutely as a doubly supported beam, and at least one of the pair of operating arm parts is elastically deformed with the minute deformation of the load receiving beam part. It is.

Here, as shown in FIG. 1, the length (the dimension from the location following the load receiving beam portion 7 to the location following the connecting portion 9) L of the operating arm portions 11 </ b> A and 11 </ b> B is set at the load receiving beam portion 7. Set sufficiently larger than the distance L ₀ between the pair of fulcrum receiving areas 15A and 15B, or make the sectional area of the operating arm parts 11A and 11B smaller than the load receiving beam part 7 or devise the shape. If the rigidity is adjusted so as to be smaller than that of the load receiving beam portion 7 by a method such as addition, or if the adjustment of these dimensions and the adjustment of the rigidity are combined, the operation arm portions 11A and 11B are generated. The strain can be easily made larger than the strain generated in the load receiving beam portion 7 itself. In that case, the strain of the load receiving beam portion 7 is amplified by the operating arm portion 11A, and the strain sensor 5 detects the amplified strain. Accordingly, the output voltage of the Wheatstone bridge circuit 23 is also increased, and the load applied to the load receiving beam portion 7 can be detected with high accuracy.

In the above description, the strain sensor 5 is composed of four strain gauges R1, R2, R3, R4, and all of them are attached to the outer surface of one of the operating arm portions 11A. May be partly or wholly attached to the inner surface of the actuating arm 1A (the surface facing the hollow portion 17). Further, a part of the four strain gauges R1, R2, R3, and R4 may be attached to one operating arm portion 11A and the rest may be attached to the other operating arm portion 11B.
Further, only one to three of the four resistors of the Wheatstone bridge circuit 23 shown in FIG. 3 are attached to one or both of the operating arm portions 11A and 11B as strain gauges, and the remaining resistors. Of course, a dummy resistor (fixed resistor) may be used.

Furthermore, in the example illustrated in FIGS. 1 to 4, the pair of left and right operating arm portions 11 </ b> A and 11 </ b> B has been described as projecting in parallel with the reference plane P, but the operating arm portions 11 </ b> A and 11 </ b> B are Further, it may be formed so as to protrude from the load receiving beam portion 7 in a direction inclined with respect to the reference plane P, and an example in that case is shown in FIG.
In the example of FIG. 5, the operating arm portions 11A and 11B are inclined by an angle θ with respect to the reference plane P so that the distal ends in the length direction are close to each other, and the adjacent distal end portions are connected to each other. The parts 9 are connected.
Even in such a configuration, the load receiving beam portion 7 is bent and deformed by the load W applied to the load receiving region 13 of the load receiving beam portion 7 as in the example shown in FIGS. Since the operating arm portions 11A and 11B are deformed so as to project to the left and right and the outer and inner surfaces of the operating arm portions 11A and 11B are distorted, the strain is detected by the strain sensor 5. The load W can be measured.

  In addition, in FIG. 5, although the front end side of the length direction of the action | operation arm parts 11A and 11B shall be inclined in the direction which adjoins mutually, conversely, the front end side of the length direction of the action arm parts 11A and 11B is Of course, it may be inclined with respect to the reference plane P so as to be separated from each other. Furthermore, only one of the operating arm portions 11A and 11B may be inclined with respect to the reference plane P, and the other may be configured to be parallel to the reference plane P.

  Further, in the example shown in FIG. 1 and FIG. 2, the lowermost ends of the operating arm portions 11A and 11B are connected by the connecting portion 9, but the portion connected by the connecting portion 9 is basically the operating arm portion. Any location on the tip side of the attachment position of the strain sensor 5 in 11A and 11B may be used. Therefore, for example, as shown in FIG. 6, the lower ends of the operating arm portions 11 </ b> A and 11 </ b> B may be extended downward from the connecting portion 9. Such a shape may be advantageous depending on the shape and structure of the load detector installation location in the load measuring device or facility. In this case, as indicated by a chain line in FIG. 6, the operating arm portions 11A, 11B are further lowered by a separate connecting portion 9 'below the connecting portion 9 (the lowermost end portion of the operating arm portions 11A, 11B). It is good also as a structure which connected.

Here, in each example of the load cell 2 described above, it is assumed that the pair of left and right working arm portions 11A and 11B have the same rigidity, and the pair of working arm portions 11A and 11B are equally deformed when a load is applied. Show.
However, when the strain is detected only by one of the pair of operating arm portions 11A and 11B, the rigidity of each of the operating arm portions 11A and 11B is made substantially different, and the operating arm portion on one side is substantially changed. It is desirable that only 11A be deformed to cause distortion. The principle configuration in that case is shown in FIGS.

7 and 8, of the pair of operating arm portions 11A and 11B, the operating arm portion 11B on the right side (the side where the strain sensor 5 is not provided) is relatively rigid by, for example, increasing the cross-sectional area. The deformation is less likely to occur when a load is applied. On the other hand, the working arm portion 11A on the left side (the side where the strain sensor 5 is provided) has a cross-sectional area smaller than that of the working arm portion 11B, for example. The rigidity is relatively small so that deformation is likely to occur when a load is applied.
With such a configuration, as shown in FIG. 8, a pair of operating arm portions is generated along with the deformation of the load receiving beam portion 7 when a load is applied to the load receiving region 13 of the load receiving beam portion 7. Among the actuators 11A and 11B, the right working arm portion 11B having high rigidity is not deformed or its deformation amount is slight, whereas the left working arm portion 11A having low rigidity is relatively largely deformed ( In the same manner as already described, the strain sensor 5 (strain gauges R1, R2, R3, R4) attached to the working arm portion 11A is used to deform the working arm portion 11A. Strain, and thus load, is detected.

  In such a configuration, as described above, mainly only one operating arm portion 11A is deformed, and therefore, the operating arm portion on the side where the strain sensor 5 is provided, as compared with the case of the basic configuration shown in FIGS. The strain amount of 11A increases, and as a result, the load can be detected with higher accuracy.

  In the case of the load cell 2 shown in FIG. 7, if a load W is applied to the load receiving beam portion 7 in the vertical direction, the working arm portion 11A on the side (left side) having a lower rigidity of the pair of working arm portions 11A and 11B. 8 is not only bent and deformed in a curved shape as shown in FIG. 8, but also the working arm portion 11B on the side with the higher rigidity (right side) is tilted slightly counterclockwise from the vertical direction with reference to the fulcrum receiving region 15B. (Inclination so that the lower end side moves to the right), the position of the connecting portion 9 also moves slightly to the right, but its inclination angle and amount of movement are negligible, so in FIG. Ignored and not specifically shown on the drawing.

  As described above, the principle configuration of the load cell in the load detector used in the bed with the load detection function of the present invention has been described. Based on such a principle configuration, a more specific load cell of the load detector is illustrated in FIG. 9 to 13 show. 9 to 13, the same components as those in the basic configuration shown in FIGS. 1 to 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The load cell 2 of the load detector 1 shown in FIGS. 9 to 13 is basically a base to which a load W is applied, as in the examples shown in FIGS. 1 and 2 and the examples shown in FIGS. 3 and a strain sensor 5 (strain gauges R1, R2, R3, R4). The base 3 includes a load receiving beam portion 7 having a load receiving region 13 and a pair of fulcrum receiving regions 15A and 15B, and a pair of operating arm portions 11A and 11B protruding from left and right positions in the load receiving beam portion 7; It consists of the connection part 9 which connects the parts by the side of the front end of these action | operation arm parts 11A and 11B, and these parts are set as the structure which continuously surrounds the hollow part 17 as a whole. In the case of this example, the left and right actuating arm portions 11A and 11B are configured such that their rigidity is unbalanced according to the example shown in FIGS.

  The load applying member 21 for applying a load is composed of a shaft member having a horizontal axis, and the support members (reference numerals 19A and 19B in each example of FIGS. 1 to 4) are vertical in this example. A hollow cylindrical member 19 having an axis is formed, and end portions of the cylindrical member (supporting member) 19 at symmetrical positions with respect to the axial line are set as support portions 19C and 19D. The hollow tube member 19 may be a cylinder or a square tube. And it is comprised so that the action | operation arm parts 11A and 11B of the base | substrate 1 may be inserted into this cylinder member 19 from upper direction.

  In the load cell 2 of the load detector 1 shown in FIGS. 9 to 13, the load receiving region 13 of the load receiving beam portion 7 in the base body 3 is formed with a bearing portion 25 whose vertical section is curved in an arc shape. The bearing portion 25 is configured to receive the horizontal shaft member (load application member) 21 described above. Then, projecting side portions 27A and 27B projecting upward from both the left and right sides of the bearing portion 25 are formed continuously and integrally, and the horizontal shaft member (load applying member) 21 is formed between the projecting side portions 27A and 27B. Is configured to be inserted.

  Further, as described above, if a plane passing through the center position O of the load receiving beam portion 7 and orthogonal to the length direction of the load receiving beam portion 7 is defined as the reference plane P, the left side portion of the base 3 ( Of the portion on the side where the strain sensor 5 is located), the upper portion is cut from the side along a vertical plane orthogonal to the reference plane P, and a cut portion 29 (see FIGS. 10 and 12) is formed. It is formed and has a bifurcated shape by the cut portion 29. Specifically, from the left portion including the bearing portion 25 (load receiving region 13) in the load receiving beam portion 7 to the middle in the length direction of the left operating arm portion 11A among the left and right operating arm portions 11A and 11B. A cut portion 29 is formed over the portion of the load receiving beam portion 7 from the bearing portion 25 (load receiving region 13) to the one fulcrum receiving region 15A side, and the middle of one operating arm portion 11A continuous thereto. The part up to the position is bifurcated.

Further, as shown in FIGS. 9 and 13, the operating arm portion 11A is formed with an inclined surface 31 on the outer surface of the portion from the upper portion to the intermediate portion, and the width in the portion from the upper portion to the intermediate portion. (Width in the direction orthogonal to the thickness direction) is made narrower, and further, on the inner surface side of the operating arm portion 11A, a plurality of recesses 33A, 33B recessed toward the outer surface side of the operating arm portion 11A, 33C is formed at intervals in the length direction (vertical direction) of the operating arm portion 11A. That is, the first concave portion 33A is formed near the lower end portion (portion following the connecting portion 9) in the operating arm portion 11A, and the second concave portion 33B is formed at a position slightly above the first concave portion 33A. Furthermore, a third recess 33C is formed at a position above that (position above the center in the length direction of the operating arm 11A).
Of the four strain gauges R1, R2, R3, R4 constituting the strain sensor 5, the strain gauges R1, R3 are attached to the outer surface at a position corresponding to the second recess 33B, and the strain gauges R2, R3, R4 is attached to the outer surface at a position corresponding to the first recess 33A.
These strain gauges R1, R2, R3, and R4 are assembled in the Wheatstone bridge circuit 23 shown in FIG. 3 as described above.

FIG. 14 shows a situation when a load is applied to the load cell 2 of the load detector 1 shown in FIGS.
In FIG. 14, the operating arm portions 11A and 11B are inserted into the upper end portion of the hollow cylindrical member (support member) 19, and the fulcrum receiving regions 15A and 15B on the lower surfaces (step surfaces) of both end portions of the load receiving beam portion 7 are If the load W is applied to the load receiving region 13 from the horizontal shaft member (load applying member) 21 that is supported by the end edges (support portions 19C and 19D) of the cylindrical member (support member) 19 and inserted into the bearing portion 25. The load receiving beam portion 7 is deformed by a small amount such that the central portion thereof is slightly lowered downward. Here, of the pair of operating arm portions 11A and 11B, the right operating arm portion 11B is not formed with the cut portion 29 (see FIGS. 10 and 13), and is also formed with the recesses 33A, 33B, and 33C. Therefore, as compared with the left working arm portion 11A, its rigidity is remarkably large, and therefore, the right working arm portion 11B is not substantially deformed as in the example shown in FIGS. Only the left working arm 11A is bent and deformed. That is, only the left working arm portion 11A is deformed so as to project to the left (outward). In addition, the recesses 33A and 33B formed inside the operating arm portion 11A locally promote the bending deformation of the operating arm portion 11A, and the strain thus promoted is effectively detected by the strain sensor 5. The

That is, as shown in FIG. 14, the first recess 33A at the end of the operating arm portion 11A on the connecting portion 9 side locally reduces the thickness of the operating arm portion 11A and reduces rigidity. In addition, since the lower side of the first recess 33A is constrained by the connecting portion 9, the operating arm portion 11A is bent and deformed outwardly from a position very close to the connecting portion 9. Therefore, compressive strain is concentrated on the outer surface near the portion corresponding to the first recess 33A, and a large resistance change occurs in the strain gauge R2 (R4) of the strain sensor 5 due to the compressive strain.
Further, even in the vicinity of the second recess 33B formed close to the first recess 33A and above the first recess 33A, the thickness of the operating arm portion 11A at the site is locally reduced and the rigidity is reduced. Then, elastic deformation occurs in a direction opposite to the elastic deformation direction in the vicinity of the first recess 33A, and tensile strain is concentrated on the outer surface in the vicinity of the portion. The tensile strain causes a large resistance change in the strain gauge R1 (R3) of the strain sensor 5.

  Here, the load cell shown in FIG. 14 includes a type of Roverval mechanism having half of a spectacle-type Roverval mechanism. The vicinity of the portion where the first concave portion 33A and the second concave portion 33B are formed adjacent to each other is the same as the shape on one side in the eyeglass-type Roverval mechanism. In other words, in the load detector shown in FIG. 22 shown as a conventional cantilever type, it is clear if the strain body 100 in which the glasses-type robust mechanism 102 is formed is compared with the operating arm portion 11A in the present embodiment. As described above, the first concave portion 33A corresponds to the enlarged hole portion 103A at one end of the long hole 103 constituting the Roverval mechanism 102 of FIG. 22, and the second concave portion 33B is an enlarged hole portion at the other end of the long hole 103. Corresponds to 103B. When the actuating arm portion 11A is deformed, the same strain concentration effect as in the case where the glasses-type Roverval mechanism is formed in the vicinity of the portion where the first recess 33A is formed and in the vicinity of the portion where the second recess 33B is formed. In addition, reverse distortion (deformation) occurs in the vicinity of the first recess 33A and the vicinity of the second recess 33B.

Thus, by forming the recesses 33A and 33B, the compressive strain at the site of the strain gauge R2 (R4) and the tensile strain at the site of the strain gauge R1 (R3) form these recesses 33A and 33B. As a result, a large output can be obtained from the Wheatstone bridge circuit 23 described above. Therefore, the load can be detected with high accuracy, and even a slight load fluctuation can be reliably grasped.
In addition, in such a configuration, the strain gauge R2 (R4) for detecting the compressive strain and the strain gauge R1 (R3) for detecting the tensile strain are attached close to each other. It is also easy to handle the lead wires for input / output with the outside.

  In this example, the third concave portion 33C is formed for the sake of design and does not directly relate to the amplification of strain, and therefore does not necessarily have to be formed in the operating arm portion 11A.

In this example, as shown in FIGS. 9 and 14, when the operating arm portions 11 </ b> A and 11 </ b> B are inserted into an external fixed hollow cylindrical member (supporting member) 19, the cylindrical member 19. The second step surfaces 15C and 15D are formed below the fulcrum receiving regions (step surfaces) 15A and 15B so that a gap G is formed between the inner surface 19E of the actuator and the outer surfaces of the operating arm members 11A and 11B. . That is, with respect to the portion inserted into the cylindrical member (support member) 19 in the operating arm portions 11A and 11B, the distance between their outer surfaces (the left side surface of the operating arm portion 11A and the right side of the operating arm portion 11B in FIGS. 9 and 14). The gap G is adjusted so as to be generated by setting the maximum distance to the surface to be smaller than the inner diameter of the hollow cylindrical member (supporting member) 19.
In this way, by adjusting the shape and dimensions so that the gap G is generated, the deformation of the working arm portion 11A when a load is applied is allowed in the gap G, and the distortion is reliably detected. Is possible.

  Also in this example, when a load W is applied to the load receiving beam portion 7 in the vertical direction, among the pair of operating arm portions 11A and 11B, the operating arm portion 11A on the side having the lower rigidity (left side) is shown in FIG. As shown in Fig. 5, the working arm portion 11B on the rigid side (right side) is slightly tilted counterclockwise from the vertical direction with respect to the fulcrum receiving region 15B (the lower end side moves to the right) At the same time, the position of the connecting portion 9 moves slightly to the right. However, the inclination angle and the amount of movement are negligible, so in FIG. Not shown above. However, as described above, the inclination and movement can be allowed by adjusting the shape and dimensions so that the gap G is also generated on the side of the right operating arm portion 11B.

  Also in the case of this example, it is not necessary that all the four resistors R1, R2, R3, R4 constituting the Wheatstone bridge circuit 23 be strain gauges, and at least one of them is a strain gauge, Needless to say, a dummy resistor may be used for the remaining portion 11A that is attached to a position corresponding to at least one of the first recess 33A and the second recess 33B.

  Furthermore, in the example shown in FIGS. 9 to 13, strain gauges R1 to R4 are attached to the outer surface of the operating arm portion 11A. However, distortion also occurs on the inner surface side of the operating arm portion 11A. Since a large strain occurs on the inner surface (bottom surface) of the recess 33A and the second recess 33B, depending on the case, a part or all of the strain gauges R1 to R4 may be used on the inner surface side of the operating arm portion 11A. In particular, the load can be detected even if it is attached to the bottom surface of one or both of the recesses 33A and 33B. For example, the strain gauges R1 and R3 may be attached to the bottom surface of the first recess 33A, and the strain gauges R2 and R4 may be attached to the bottom surface of the second recess 33B.

FIG. 15 shows an embodiment in which the configuration for supporting the fulcrum receiving regions 15A and 15B in the load receiving beam portion 7 of the base 3 is changed.
In the case of this example, the load application member 21 for applying a load from the outside is constituted by a shaft member having a horizontal axis, as in the examples shown in FIGS. Similarly to the examples shown in FIGS. 9 to 13, the reference numerals 19 </ b> A and 19 </ b> B) in each example of FIG. 4 are also a hollow cylindrical member 19 having a vertical axis, and in the cylindrical member (support member) 19 End portions at positions symmetrical about the axis are the support portions 19C and 19D.
And the groove 41A, 41B is formed in the lower surface near the both ends of the load receiving beam part 7, and these groove 41A, 41B fits to the upper end (support part 19C, 19D) of the cylinder member (support member) 19. It is configured to be. Therefore, in this case, the inner back surfaces of the concave grooves 41A and 41B correspond to the fulcrum receiving areas 15A and 15B. In this case, the concave grooves 41A and 41B do not need to be closely fitted to the upper end of the cylindrical member (supporting member) 19 and may be fitted with a slight play. Other configurations are the same as those of the example shown in FIGS.

FIG. 16 shows still another example in which the configuration for supporting the fulcrum receiving areas 15A and 15B in the load receiving beam portion 7 of the base 3 is changed.
In the case of this example, the load application member 21 for applying a load from the outside is formed of a shaft member having a horizontal axis, as in the examples shown in FIGS. Near the both ends of the load receiving beam portion 7, mounting holes 43A and 43B penetrating the load receiving beam portion 7 are formed. When supporting the base 3 of such a load detector, pin-like members 45A and 45B are inserted into the mounting holes 43A and 43B, and the pin-like members 45A and 45B are external (in the bed main body in the present invention). It may be fixed or locked to any support member 19). In such a configuration, the attachment holes 43A and 43B correspond to the fulcrum receiving areas 15A and 15B.

  Further, in the example shown in FIGS. 9 to 13, since a horizontal shaft member is applied as the load applying member 21, the bearing portion 25 is formed in the load receiving region 13 of the load receiving beam portion 7, and the projecting side portions 27 </ b> A are formed on both sides thereof. 27B, depending on the shape of the load application member 21, the load receiving region 13 may be formed with a simple recess 13A, similar to the basic configuration shown in FIGS. An example of this case is shown in FIG. Furthermore, depending on the shape of the load application member 21, the load receiving region 13 may be a planar region that does not give a shape such as a depression.

  It should be noted that the relationship between the load receiving area 13 and the fulcrum receiving areas 15A and 15B in the load receiving beam portion 7 (relationship between the force point and the fulcrum) is only relative, and when actually using the load cell 2, It is also possible to reverse the relationship. That is, as shown in FIG. 18, the base 3 is arranged upside down, the base is supported by the load receiving area 13 of the load receiving beam portion 7, and the load from above is applied to the fulcrum receiving areas 15A and 15B. It can also be used to receive W.

Further, in the above description, the base body 3 is arranged so that the reference plane P is along the vertical direction (therefore, the length directions of the operating arm portions 11A and 11B are vertical), and the load W applied in the vertical direction. In some cases, the reference plane P may be installed and used so as to be inclined at a predetermined angle α of less than 90 degrees with respect to the vertical direction (the direction of the load W). it can. An example of use in that case is shown in FIG.
In this case, the load W from above is applied in a direction inclined by an angle α with respect to the reference plane P, but the direction along the reference plane P as a component of the vertical force F by the load W. Since the force Fp is present, the load W can be detected by flexing and deforming the load receiving beam portion 7 as described above and detecting the distortion caused by the deformation of the operating arm portion 11A.

  FIG. 20 shows another specific example of the load cell 2 in the load detector 1 used in the bed with a load detection function of the present invention. In addition, the base 3 of the load cell 2 shown in FIG. 20 is configured as shown in FIGS. 9 to 13 except for one of the pair of working arm portions 11A and 11B (the strain sensor mounting side) working arm portion 11A. It is the same as that of an example, Therefore, description is abbreviate | omitted about structures other than the operating arm part 11A.

  20, a long hole 35 penetrating the front and back is formed along the length direction of the operating arm portion 11A at a position near the connecting portion 9 in the operating arm portion 11A. Both ends of the long hole 35 are enlarged hole portions 37A and 37B whose diameters are enlarged, and the portion surrounding the long hole 35 is a so-called eyeglass-type robust mechanism 39. Strain gauges R1, R2, R3, and R4 (only R1 and R2 are shown in FIG. 20) are attached as the strain sensor 5 at a position corresponding to the robust mechanism 39 on the outer surface of the operating arm portion 11A. More specifically, the strain gauge R1 (R3) is at a position corresponding to one enlarged hole 37A on the outer surface of the operating arm portion 11A, and the strain gauge R2 (R4) is the other on the outer surface of the operating arm portion 11A. Is attached at a position corresponding to the enlarged hole portion 37B.

FIG. 21 shows a situation when the load cell 2 shown in FIG. 20 is used, particularly a situation when a load is applied.
Also in this case, as shown in FIG. 14 for the examples of FIGS. 9 to 13, the operating arm portions 11 </ b> A and 11 </ b> B are inserted into the upper end portion of the hollow cylindrical member (supporting member) 19, and the load receiving beam portion 7. The fulcrum receiving areas 15 </ b> A and 15 </ b> B are supported by the end edges (supporting portions 19 </ b> C and 19 </ b> D) of the cylindrical member (supporting member) 19. In this state, if a load W is applied to the load receiving region 13 from the horizontal shaft member (load applying member) 21 inserted in the bearing portion 25, the central portion of the load receiving beam portion 7 is slightly below. A micro-deformation deformation occurs so as to descend. Here, of the pair of operating arm portions 11A and 11B, the right operating arm portion 11B is not formed with a notch, and therefore has higher rigidity than the left operating arm portion 11A, and therefore the right operating arm portion 11B. The arm portion 11B is not substantially deformed, and only the left operating arm portion 11A is bent and deformed. That is, the left operating arm portion 11A is deformed so as to project leftward (outward). In addition, the enlarged hole portions 37A and 37B at both ends of the Roverval mechanism 39 (the long hole 35) formed in the operating arm portion 11A facilitate the deformation of the corresponding portion, and the promoted strain is the strain sensor. 5 are effectively detected by the respective strain gauges R1 to R4.

  In each of the examples of the load cell 2 described above, the base 3 is entirely composed of a rolled plate, a forged material, a cast material, or the like, which is an integrated product obtained by machining the entire shape thereof, or an integrated product obtained by extrusion. Although it is desirable to be composed of an integrally continuous material, in some cases, it may be a combined structure that is partly divided and assembled by welding or screwing. For example, since the connecting portion 9 is a portion not related to the bending deformation, only the connecting portion 9 may be formed separately and both ends thereof may be coupled to the lower end portions of the operating arm portions 11A and 11B.

  The bed with a load detection function of the present invention using the load detector as described above will be described below with reference to FIGS.

FIG. 22 is a side view showing an example of a bed 201 with a load detection function to which the present invention is applied.
The bed 201 with a load detection function includes a bed main body 201A installed on an installation surface B such as a floor surface, and is added to the bed main body 201A by the load cell 2 of the load detector 1 attached to the bed main body 201A. This is provided with a function of detecting a change in load and detecting the state of the user H on the bed surface T of the bed main body 201A.

  In the following description, the installation surface B and the bed surface T of the bed main body 201A shown in FIG. 22 are horizontal surfaces (surfaces orthogonal to the direction of gravity), and the user H is placed on the bed surface T of the bed main body 201A. Is sleeping in a supine posture, the head side of the user H is “the front side of the bed main body 201A”, the foot side of the user H is “the rear side of the bed main body 201A”, and the right side of the user H is “the bed” The right side of the main body 201A and the left side of the user H are referred to as the “left side of the bed main body 201A”.

Specifically, the bed main body 201A includes a bed surface forming unit 100 that forms the bed surface T, leg portions 204 that are in contact with the installation surface B on which the bed main body 201A is to be installed, and the bed surface forming unit 100 that is on the installation surface B. A configuration generally including a connection support portion 102 that connects the bed surface forming portion 100 and the leg portion 204 and transmits a load from the bed surface forming portion 100 toward the leg portion 204 so as to be positioned above. It is said that.
Here, in the example illustrated in FIG. 22, the bed surface forming unit 100 includes a bed plate 202 and an upper frame 203 that supports the bed plate 202. The connection support unit 102 includes a lower frame 205 and an elevating link mechanism 206 that moves the bed 202 together with the upper frame 203 while connecting the upper frame 203 and the lower frame 205.

The bed plate 202 is a rectangular flat plate having a length and width sufficient for the user H to go to bed.
The bed main body 201 </ b> A allows a user H to be present on the bed 202 in a state where, for example, a mat or a mattress is laid. (In addition, in FIG. 22, the state where the user H lies directly on the upper surface (bed surface T) of the bed 202 is illustrated.)

  The upper frame 203 includes a pair of left and right pipe frames 203a extending in the length direction of the bed plate 202 (longitudinal direction of the bed main body 201A) and a pair of front and rear extending in the width direction of the bed plate 202 (short direction of the bed main body 201A). The pipe frame 203b is connected in a frame shape as a whole, and the pipe frame 203c extending in the width direction of the bed 202 (short direction of the bed main body 201A) is the length direction of the bed 202 (longitudinal of the bed main body 201A). A structure (frame structure) connected to a pair of left and right pipe frames 203a in a state of being arranged in a plurality of directions.

  And the said bed 202 is attached in the state fixed on these several pipe frames 203c. Further, a head plate 207a and a foot plate 207b are attached to the pair of front and rear pipe frames 203b constituting the upper frame 203 in a state of being vertically erected.

  Four leg portions 204 are arranged at four corners (front left side, front right side, rear left side, rear right side) of the bed main body 201A that are in a symmetrical positional relationship. Each of the four legs 204 is provided with a caster mechanism 208 for facilitating the movement of the bed main body 201A, which is a heavy object. The configuration of the caster mechanism 208 is not particularly limited, and a conventionally known one can be used.

  The lower frame 205 has a structure in which a pair of left and right pipe frames 205a extending in the longitudinal direction of the bed main body 201A and a pair of front and rear pipe frames 205b extending in the short direction of the bed main body 201A are connected in a frame shape as a whole. Structure). The leg portions 204 (the caster mechanisms 208) are provided at both ends of a pair of left and right pipe frames 205a constituting the lower frame 205, respectively.

  A pair of elevating link mechanisms 206 in the above-described connection support portion 102 are arranged side by side on the front side and the rear side of the bed main body 201A. The front and rear elevating link mechanisms 206 have basically the same structure except that their attachment positions are different. Further, the front and rear elevating link mechanisms 206 have a symmetrical structure between the right side and the left side of the bed main body 201A, respectively.

  Accordingly, the front and rear elevating link mechanisms 206 are collectively described as necessary, for example, as shown in FIGS. 23 (a) and 23 (b).

  FIG. 23A is a side view of the main part of the bed main body 201A showing a state in which the bed 202 is lowered together with an upper frame (not shown) by the lift link mechanism 206. FIG. On the other hand, FIG. 23 (b) is a side view of the main part of the bed main body 201A showing the state in which the bed 202 is lifted together with the upper frame (not shown) by the lift link mechanism 206.

  Specifically, as shown in FIGS. 23A and 23B, the elevating link mechanism 206 includes first to third connection arms that are connected to each other between the upper frame 203 and the lower frame 205. 209a, 209b, and 209c are provided in a pair of left and right.

  Among these, the 1st connection arm 209a is attached in the state which the lower end part fixed to the pair of pipe frames 205b which comprises the said lower frame 205. The first connecting arm 209a has a hollow cylindrical portion 103 formed at least on the upper end side (the side far from the lower frame 205). On the other hand, the lower end of the second connecting arm 209b is rotatably attached via the upper end of the first connecting arm 209a and the first hinge part 210a. On the other hand, the lower end of the third connecting arm 209c is rotatably attached via the upper end of the second connecting arm 209b and the second hinge part 210b.

  The elevating link mechanism 206 has a pair of left and right fourth connection arms 209d that connect the front and rear third connection arms 209c. And the upper end part of the 3rd connection arm 209c of the front side and the rear side is each rotatably attached to this 4th connection arm 209d via the 3rd hinge part 210c.

  The elevating link mechanism 206 has an actuator (driving mechanism) 211 for elevating and driving the bed plate 202 together with an upper frame (not shown). The actuator 211 moves (extends / contracts) the piston 211b from the cylinder 211a in the front-rear direction by electric drive. Among these, the cylinder 211a is attached in a state of being fixed to the upper frame 205 (not shown in FIGS. 23A and 23B). On the other hand, the piston 211b is rotatably attached at its tip via a fourth connecting arm 209d and a fourth hinge 210d. The actuator 211 is provided only on one of the left and right sides of the bed main body 201A.

  In the lifting link mechanism 206, as shown in FIG. 23A, the piston 211b moves forward (extends) by driving the actuator 211 from the state where the bed plate 202 is lowered together with the upper frame (not shown). Thus, while the first to fourth connecting arms 209a to 209d cooperate with each other, as shown in FIG. 23B, the bed 202 is raised together with the upper frame (not shown). Conversely, as shown in FIG. 23 (b), the piston 211b moves backward (shrinks) by driving the actuator 211 from the state where the bed 202 is lifted together with the upper frame (not shown), so that the first to first While the four connecting arms 209a to 209d cooperate with each other, as shown in FIG. 23 (a), the bed 202 is lowered with the upper frame (not shown). Thereby, it is possible to adjust the height of the bed 202 while moving the bed 202 together with an upper frame (not shown).

  As shown in FIG. 22, the load detector 1 includes the load cell 2 as described above that measures the strain generated when a load is applied to the bed main body 201 </ b> A. As shown in FIG. 22, in addition to the load cell 2, based on a load signal output from the load cell 2, a calculation unit 252 that calculates the state of the user H on the bed surface T of the bed body 201 </ b> A; The transmission unit 253 that remotely transmits the result calculated by the calculation unit 252 and the reception unit 254 that receives the signal transmitted from the transmission unit 253 are roughly provided.

  Note that the load cell 2 and the calculation unit 252 and the calculation unit 252 and the transmission unit 253 are electrically connected by wires 255a and 255b, respectively. On the other hand, transmission / reception is possible between the transmission unit 253 and the reception unit 254 by radio (radio waves).

By the way, the bed 1 with a load detection function to which the present invention is applied is from the bed surface forming part side 100 in any part of the load transmission path from the bed surface forming part 100 to the leg part 204 through the connection support part 102. The load cell 2 is incorporated in a portion that receives a load and transmits the load to the installation surface B side.
In particular, in the case of the example of FIG. 22, the load cell 2 is incorporated in the elevating link mechanism 206 of the connection support portion 102 in the load transmission path. Therefore, here, the case where the load cell 2 is incorporated in the lifting link mechanism 206 as described above will be described in more detail.

  Specifically, as shown in FIGS. 23A and 23B, the load cell 2 has a symmetrical positional relationship among the first to fourth hinge portions 210 a to 210 d constituting the elevating link mechanism 206. Are attached to each of the first hinge portions 210a arranged at the four corners (front left side, front right side, rear left side, rear right side). These four load cells 2 have basically the same structure except that their mounting positions are different. Here, for example, the load cell 2 shown in FIGS. 9 to 13 is used. .

  FIG. 24A is an enlarged side view of the main part of the lifting link mechanism 206 in which the load cell 2 is incorporated. On the other hand, FIG.24 (b) is the front view to which the principal part of the raising / lowering link mechanism 206 incorporating the load cell 2 was expanded.

  Specifically, as shown in FIGS. 24A and 24B, the first hinge portion 210a has a guide slit (bearing) 212 provided in the first connecting arm (one connecting arm) 209a. In addition, the pin (support shaft) 213 provided on the second connection arm (the other connection arm) 209b is pivotally supported while being engaged, whereby the first connection arm 209a is The second connecting arm 209b has a structure that is rotatably supported. Here, the pin (support shaft) 213 corresponds to the horizontal shaft member (load application member) 21 in FIGS. 9 to 13.

  The load cell 2 basically includes a base 3 that generates strain due to a load from the bed surface forming unit 100 and a strain sensor 5 attached to the base to detect the strain of the base. . As described above, the base 3 includes the load receiving beam portion 7, the operating arm portions 11 </ b> A and 11 </ b> B, and the connecting portion 9, and the load receiving beam portion 7 has the bearing portion 25. Is formed. And the base | substrate 3 is inserted in the hollow cylinder part 103 of the 1st connection arm 209a.

  In the load cell 2, when a load is applied to the bed main body 201 </ b> A, a vertically downward load W is applied to the load receiving beam portion 7, so that amplified distortion occurs in the operating arm portion 11 </ b> A as described above. become. At this time, the strain sensor 5 detects a change in resistance corresponding to the magnitude of the distortion generated in the operating arm portion 11A, and outputs a load signal corresponding to the magnitude of the distortion. Thereby, it is possible to detect a change in the load applied to the bed main body 201A.

  In the load detector 1, changes in loads applied to the four corners of the bed main body 201 </ b> A by the four load cells 2 disposed at the four corners (front left, front right, rear left, and rear right) of the bed main body 201 </ b> A, respectively. Is detected. Then, the load signals detected by these four load cells 2 are output to the calculation unit 252.

  The calculation unit 252 includes a computer having a ROM, a RAM, other memory, a CPU, and the like, and stores in advance programs, numerical values, and the like necessary to calculate the state of the user H on the bed surface T of the bed body 201A. Has been.

  And in this calculating part 252, based on the load signal output from the said four load cells 2, the state of the user H on the bed surface T of the said bed main body 201A is calculated, and the calculation result is sent to the transmission part 253. Output.

  For example, in the calculation unit 252, when the total value of loads applied to the four load cells 2 is larger than a prestored threshold value from the load signals output from the four load cells 2, the user H It is determined that the user is on the bed surface T of the bed main body 201 </ b> A, and the calculation result is output to the transmission unit 253.

  In addition to the user's H entering (sleeping) and getting out (getting up), for example, the calculation unit 252 also includes, for example, the position of the center of gravity of the user H on the bed surface T of the bed main body 201A (the presence of the floor). It is also possible to perform calculations for predicting the leaving of the user H from the position. Furthermore, it is also possible to detect the body movement (eg, turning over etc.) and posture (eg: supine, prone, lying down, etc.) of the user H by calculation.

  The transmission unit 253 is a transmitter attached to the bed main body 201 </ b> A, and transmits the result calculated by the calculation unit 252 to the remote reception unit 254. On the other hand, the receiving unit 254 is a receiver that receives the signal transmitted from the transmitting unit 253, and remotely monitors the state of the user H (the occupancy status) by receiving the signal from the transmitting unit 253. It becomes possible.

  On the receiving unit 254 side, the detection result detected by the load cell 2 and the calculation result by the calculation unit 252 can be displayed on a monitor (not shown) or output to a printer, for example. .

  Further, from the calculation result by the calculation unit 252, for example, the state of the user H may be notified to the monitor as necessary. The notification method is not particularly limited, and for example, it is possible to issue an alarm from a speaker (not shown) or display on a monitor.

  The bed with a load detection function having the above-described structure is suitably used in, for example, medical facilities (eg, hospitals, clinics, etc.), nursing facilities, nursing homes, and the like.

  In the present invention, by using such a bed 201 with a load detection function, for example, getting into bed (sleeping), getting out of bed (getting up), standing position, body movement (eg, turning over, etc.), posture (eg: It becomes possible to remotely monitor the state of the user H (the presence of bed) such as supine, prone, and lying. Further, by using such a bed 201 with a load detection function, it is necessary to constantly monitor the user H not only in the middle of the night or early morning, but also in the mental burden of the user H being monitored by someone. It is possible to reduce the physical and mental burden of the observer.

  In addition, such a bed 201 with a load detection function is not limited to the above-described facilities, and for example, accommodation facilities (eg, hotels, inns, etc.), general homes (eg, home care, etc.), etc. Can also be used. That is, the usage form of the bed 201 with the load detection function is not particularly limited.

  Moreover, as an application example using the load detection function of the bed 201 with a load detection function to which the present invention is applied, for example, a “floor slip prevention function” can be cited. Specifically, when the position of the center of gravity has not moved outside a certain circle for a certain time (for example, 2 hours) or more, or when the load change of each load cell 2 has not changed for a certain (for example, 1 kg) or more In addition, it is possible to add a function of determining that there is a possibility of a bed slip in the user H and notifying the supervisor.

  Another application example is “lighting control function”. Specifically, by measuring the gravity center position of the user H on the bed surface T of the bed main body 201A, the movement amount of the gravity center, the movement speed of the gravity center, etc., the lighting is turned on when entering or leaving the floor. A function of turning off the light can be added.

  Another application example is “weight management function”. Specifically, it is possible to add a function of managing the weight of the user H by measuring the weight of the user H on the bed surface T of the bed main body 201A periodically (for example, every day). It is.

  Another application example is “air conditioning management function”. Specifically, by detecting the body movement of the user H on the bed surface T of the bed main body 201A (such as turning over), the sleep depth of the user H is measured, and air conditioning is managed according to the state of the user. It is possible to add a function such as

  Another application example is “weight monitoring function during dialysis”. Specifically, it is possible to add a function of detecting the start and end of dialysis by measuring the weight of the user H on the bed surface T of the bed main body 201A.

  As described above, in the present invention, various functions can be added by using the load detection function of the bed 201 with the load detection function as well as the functions described above.

  Further, the present invention may be a bed with a load detection function in which the load detector 1 is preliminarily incorporated in the bed main body 201A, or by loading the load detector 1 in the bed main body 201A separately, A detection function may be added.

  That is, the bed with a load detection function to which the present invention is applied measures the change in the load applied to the bed main body 201A by the load detector 1 attached in advance to the bed main body 201A or separately attached, thereby the bed of the bed main body 201A. It is possible to detect the state of the user H on the surface T.

  In the present invention, by attaching the load detector 1 to which the present invention is applied to the bed main body 201A, it is possible to add a load detection function to the bed with a simple structure while suppressing an increase in the number of parts. ing.

Specifically, in the load detector 1 to which the present invention is applied, the load cell 2 is a component (the guide slit 212 is included in the first hinge arm 210 of the first connecting arm 209a included in the existing bed). A load detecting component replaceable with a formed bearing member) is formed.
For this reason, the base 3 constituting the load cell 2 has the same mounting structure as that of the bearing member in the bearing portion 25.

  Therefore, in the present invention, the bed body 201A can be replaced by simply replacing the four bearing members arranged at the four corners (front left side, front right side, rear left side, rear right side) and the load cell 2 of the bed main body 201A. The load detector 1 can be easily incorporated.

  Thereby, it is possible to add a load detection function to an existing bed at low cost. Further, even when a failure or the like occurs in the load cell 2, it can be easily replaced. Furthermore, since there is little difference with the existing bed, it is possible for the user H to use the bed without a sense of incongruity.

  In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

  For example, the bed 201 with the load detection function has a configuration in which the load cell 2 is incorporated in the first hinge portion 210a that configures the lifting link mechanism 206. It is also possible to adopt a configuration in which the load cell 2 is incorporated in the second hinge part 210b or the third hinge part 210c constituting the link mechanism 206.

  Further, the bed main body 201A may be one in which a mat or the like is previously laid on the bed 202. Further, the bed 202 has a structure that is divided in the length direction (longitudinal direction of the bed main body 201A) and has a reclining function in which a part of the upper body side or the foot side of the user H rises. It may be. Furthermore, the upper frame 203 and the lower frame 205 are not limited to the above-described frame structure, and various frame structures can be employed.

  Further, the load detector 1 is not limited to the configuration in which the load cell 2 and the calculation unit 252 and the calculation unit 252 and the transmission unit 253 are electrically connected by the wires 255a and 255b. It is also possible to adopt a configuration in which they are electrically connected. On the other hand, the communication method between the transmission unit 253 and the reception unit 254 is not limited to the above-described wireless communication network, and a wired communication network may be used. Further, in the load detector 1, the calculation unit 252 and the transmission unit 253 can be integrally formed.

  Further, in the above-described embodiment, the first connecting arm 209a in the lifting link mechanism 206 is fixed to the pair of front and rear pipe frames 205b of the lower frame 205 so as to be inclined with respect to the lower frame 205 (see FIG. 24 (a)), the first connecting arm 209a may be fixed so as to be perpendicular to the lower frame 205. The situation in that case is shown in FIG. 25 according to FIG.

  As shown in FIG. 25, even when the first connecting arm 209a of the lifting link mechanism 206 is vertical, the load cell 2 is inserted into the hollow cylindrical portion of the connecting arm 209a so that the whole of the load cell 2 is along the vertical direction. In addition, by receiving the pin (support shaft) 213 provided on the second connecting arm (the other connecting arm) 209b by the bearing portion 25, the load can be detected in the same manner as described above.

  In each of the above-described embodiments, the load cell 2 is incorporated in the bed main body so that the load receiving portion 7 is located above and the connecting portion 9 is located below. However, the relationship between the load receiving portion and the load transmitting portion. Of course, these are relative and may be incorporated into the bed body upside down. An example in that case is shown in FIG.

  In FIG. 26, between the upper end part of the 1st connection arm 209a and the lower end part of the 2nd connection arm 209b of the raising / lowering link mechanism 206 is attached rotatably via the 1st hinge part 210a, The pin (support shaft) 213 of the first hinge portion 210a is provided on the lower first connecting arm 209a side. The bearing portion 25 of the base 3 in the load cell 2 is engaged with the pin 213, and the connecting portion 9 of the base 3 in the load cell 2 is inserted into the upper second connecting arm 209b. In this case, the load of the bed main body is applied to the fulcrum receiving areas 15a and 15b of the base 3, but even in that case, the load can be detected by the distortion of the operating arm portion 11A.

  Further, in each of the above-described embodiments, the elevating link mechanism 206 is provided in the connection support portion 102 between the upper frame 203 and the lower frame 205, but the elevating link mechanism 206 is not provided in the connection support portion 102. The present invention can also be applied to cases. An example thereof is shown in FIGS.

  In the embodiment shown in FIGS. 27 and 28, the upper frame 203 and the lower frame 205 are connected by, for example, a plurality of hollow pipe-like (usually four) vertical columns 102A as the connection support portion 102. In this configuration, the load cell 2 is interposed between the upper end of each column 102 </ b> A and the upper frame 203. That is, the operating arm portions 11A and 11B and the connecting portion 9 of the base 3 of the load cell 2 are inserted into the upper end portion of the hollow pipe-like column 102A, and the flat upper surface of the load receiving beam portion 7 of the base 3 is the upper side. The shaft 203 is disposed so as to be in contact with the front end surface (lower surface) of the shaft rod portion (load applying member) 106A that protrudes vertically downward from the receiving member 106 fixed to the lower surface of the frame 203. Even when the load cell 2 is arranged in this manner, the load applied from the upper frame 203 can be detected.

  Other examples in the case where the lifting / lowering link mechanism 206 is not provided in the connection support portion 102 are shown in FIGS.

  In the embodiment shown in FIGS. 29 and 30, as in the embodiment shown in FIGS. 27 and 28, a plurality of, for example, hollow pipes as the connection support portion 102 are provided between the upper frame 203 and the lower frame 205. In this case, the load cell 2 is interposed between the lower end of each column 102A and the lower frame 205. That is, the operating arm portions 11A and 11B and the connecting portion 9 of the base 3 of the load cell 2 are inserted into the lower end portion of the hollow pipe-like column 102A, and the lower frame is placed on the lower surface of the load receiving beam 7 of the base 3. The front end surface (upper surface) of the shaft bar portion (load application member) 108A that protrudes vertically upward from the receiving member 108 fixed to the upper surface of 205 is disposed so as to contact. Even when the load cell 2 is arranged in this way, it is possible to detect a load applied from the upper frame 203 via the support column 102A.

  The embodiment shown in FIGS. 27 and 28 and the embodiment shown in FIGS. 29 and 30 are all provided with no lifting link mechanism in the connection support portion 102 between the upper frame 203 and the lower frame 205. However, even in the case where the elevating link mechanism is provided in the connection support portion 102, the upper frame 203 and the connection support portion 102 (for example, the upper frame) can be used according to the embodiment shown in FIGS. 27 and 28. 203 and between the lifting link mechanism). Similarly, even when a lifting / lowering link mechanism is provided in the connection support portion 102, according to the embodiment shown in FIGS. 29 and 30, between the connection support portion 102 and the lower frame 205 (for example, the lifting / lowering link mechanism and the lower link mechanism). The load cell 2 can be interposed between the side frame 205 and the side frame 205.

  Furthermore, in the case where no lifting link mechanism is provided in the connection support portion 102 between the upper frame 203 and the lower frame 205 as in the embodiment shown in FIGS. 27 and 28 or the embodiment shown in FIGS. 29 and 30. In addition, the load cell 2 can be interposed in an intermediate portion of each column 102A constituting the connection support portion 102.

  If the lifting link mechanism 6 is not provided (see the embodiment shown in FIGS. 27 and 28, for example), the lower frame 205 may also be omitted. In this case, a leg portion is provided at the lower end of each column 102A. A caster mechanism 208 as 204 may be provided directly. Even in the bed main body having such a configuration, the load cell 2 may be interposed between the upper frame 203 and each of the columns 102A according to the embodiment shown in FIGS.

  As described above, the bed 1 with a load detection function to which the present invention is applied has a connecting support portion (lifting / lowering) from the bed surface forming portion (in the above-described embodiments, constituted by the bed plate 202 and the upper frame 203). (The presence or absence of the link mechanism 206 or the lower frame 205 does not matter.) In response to a load from the bed surface forming portion 100 side in any part of the load transmission path passing through 102 to the leg portion 204, the load is applied to the installation surface B. The load cell 2 should just be integrated in the site | part which transmits to the side. Therefore, the load cell 2 is either between the bed surface forming part 100 and the connection support part 102, between the connection support part 102, between the connection support part 102 and the leg part 4, and further to the leg part 204. May be interposed.

  In each of the above-described embodiments, the bed surface forming unit 100 that forms the bed surface T in the bed main body 201 </ b> A is configured by the bed 202 and the upper frame 203 that supports the bed 202. In some cases, the bed surface forming unit 100 may be one without the upper frame 203, that is, only the bed 202. Of course, the present invention can also be applied to such a case. For example, the load cell 2 may be interposed between the bed 202 and a connection support portion (for example, the support column 102A) for supporting it.

  In the same manner as described above, when the bed surface forming part 100 is not provided with the upper frame 203, that is, only the bed 202, the lifting support mechanism 102 is connected to the connecting support part 102 for supporting the bed 202. There is also a bed main body having a configuration in which 206 is provided so that the bed 202 is directly raised and lowered. Of course, the present invention can also be applied to such a case.

  Furthermore, even if the bed surface forming unit 100 includes the upper frame 203, there is also a bed main body in which the elevating link mechanism 206 directly raises and lowers the bed 202 by simply functioning as an upper frame 203, In such a case, since the upper frame 203 does not substantially support the load, the upper frame 203 is removed from the load transmission path from the bed surface forming portion 100 to the leg portion 204 via the connection support portion 102. And in that case, what is necessary is just to interpose the load cell 2 in any part of the load transmission path | route from the bed 202 to the leg part 204 via the connection support part 102. FIG.

  In the above description, a link mechanism is applied as a mechanism for raising and lowering the bed surface forming unit 100. However, in some cases, an elevating mechanism that does not use a link mechanism, for example, a manual or electric rotary screw system Of course, a lifting mechanism such as a screw method or a jack method may be used, and the present invention can be applied to a bed body having a lifting mechanism other than the link mechanism.

  Further, in each of the above-described embodiments, a strain gauge whose electric resistance changes due to strain is used as a strain sensor for the load cell. However, the strain sensor can be used as long as it can detect strain of the operating arm of the load cell. For example, a conductive elastomer sensor element, an optical strain sensor element, an electrostrictive device sensor element, a piezoelectric device sensor element, a magnetostrictive device sensor element, or the like can also be used.

DESCRIPTION OF SYMBOLS 1 ... Load detector 2 ... Load cell 3 ... Base | substrate 5 ... Strain sensor 7 ... Load receiving beam part 9 ... Connection part 11A, 11B ... Actuating arm part 13 ... Load receiving area | region 15A, 15B ... Supporting point receiving area 17 ... Hollow part 19, 19A, 19B ... support member 21 ... load application member 39 ... Roverval mechanism 100 ... bed surface forming part 102 ... connection support part 103 ... hollow cylinder part 201 ... bed with load detection function 201A ... bed main body 202 ... bedding plate 203 ... upper frame 204 ... Leg 205 ... Lower frame 206 ... Elevating link mechanism 208 ... Caster mechanism 209a ... First connecting arm 209b ... Second connecting arm 209c ... Third connecting arm 209d ... Fourth connecting arm 210a ... First Hinge portion 210b ... second hinge portion 210c ... third hinge portion 210d ... fourth hinge portion 211 ... Actuator 212 ... Guide slit (bearing) 213 ... Pin (support shaft) 252 ... Calculation unit 253 ... Transmission unit 254 ... Reception unit
B ... installation surface T ... sleep surface H ... User _{R 1, R 2, R 3} , R 4 ... strain gauges (resistance)

Claims (22)

The load detector attached to the bed body detects a change in the load applied to the bed body, and a bed with a load detection function for detecting the state of the user on the bed surface of the bed body,
The bed body includes a bed surface forming portion that forms the bed surface, legs that are in contact with an installation surface on which the bed body is to be installed, and the bed surface so that the bed surface forming portion is located above the installation surface. It is configured to have a connection support part that connects the forming part and the leg part and transmits the load from the bed surface forming part toward the leg part,
The load detector has a load cell that measures strain generated by applying a load to the bed body,
The load cell includes a base body to which a load is applied from the bed surface forming portion side, and a strain sensor attached to the base body.
The base body includes a load receiving beam portion having a load receiving region and a pair of fulcrum receiving regions, a pair of operating arm portions projecting from different positions in the load receiving beam portion, and a tip side portion of the pair of operating arm portions The load receiving beam portion, the pair of operating arm portions and the connecting portion are configured so as to continuously surround the hollow portion as a whole,
The load receiving area is formed at a position corresponding to a reference plane crossing a straight line connecting the pair of fulcrum receiving areas in the middle of the pair of fulcrum receiving areas, and the load receiving area is along the reference plane Configured to receive loads applied in the direction,
Further, one of the pair of operating arm portions protrudes from a side on which one of the pair of fulcrum receiving regions is located with respect to the reference plane in the load receiving beam portion, and The other is formed so as to protrude from the side where the other fulcrum receiving region of the pair of fulcrum receiving regions is located with respect to the reference surface in the load receiving beam portion,
The strain sensor is attached to at least one of the pair of operating arm portions, and applies the load along the reference plane to the load receiving area while supporting the pair of fulcrum receiving areas. At least one of the actuating arm portions is elastically deformed, and the strain sensor is configured to detect the strain of the elastic deformation,
In response to a load from the bed surface forming portion side at any part of the load transmission path from the bed surface forming portion to the leg portion through the connection support portion in the bed body, the load is transmitted to the installation surface side. A bed with a load detection function, wherein a base of the load sensor is provided at a site. In the bed with a load detection function according to claim 1;
A bed with a load detection function, wherein each of the load receiving areas in the load cell is configured by a surface in contact with a load application member to which a load from a bed surface forming portion is guided. In the bed with a load detection function according to claim 1;
The strain sensor is attached to one or both of a surface facing the outside and a surface facing the inner side among the surfaces of the at least one operating arm portion. Bed with load detection function. In the bed with a load detection function according to claim 3;
One working arm of the pair of working arms is made to be less rigid than the other working arm, and the strain sensor is attached to the one working arm. A bed with a load detection function. In the bed with a load detection function according to claim 4;
When a concave portion is formed on the inner and / or outer surface facing the hollow portion of one of the pair of operating arm portions and the one operating arm portion is elastically deformed, the operation is performed. A bed with a load detection function, which is configured to amplify the strain of a portion of the arm corresponding to the concave portion, and to which the strain sensor is attached. In the bed with a load detection function according to claim 4;
Two or more concave portions are formed at intervals in the length direction of the working arm portion on one of the pair of working arm portions on the inner and / or outer surface facing the hollow portion. In addition, when the operating arm portion is elastically deformed, the strain of the portion corresponding to each of the two or more recesses in the operating arm portion is configured to be amplified,
In addition, the strain sensor is composed of one or more strain detection elements, and at least one of the one or more strain detection elements corresponds to at least one of the two or more recesses. A bed with a load detection function, characterized in that it is attached to a part to perform. In the bed with a load detection function according to claim 6;
The strain sensor is composed of two or more strain detection elements, and at least one of the two or more strain detection elements is one of the two or more adjacent recesses. The bed with a load detection function is characterized in that at least one other strain detection element is attached to a portion corresponding to the other of the two or more adjacent recesses. In the bed with a load detection function according to any one of claims 1 to 7;
One of the pair of actuating arm parts is formed with a Roverval mechanism, and when the one actuating arm part is elastically deformed, distortion of the actuating arm part is amplified by the Roverval mechanism. A bed with a load detection function, characterized in that a strain sensor is attached to the one operating arm.
Functional bed. In the bed with a load detection function according to any one of claims 1 to 8;
A bed with a load detection function, wherein the pair of fulcrum receiving areas in the load cell are each formed by a surface that is supported in contact with a fixed part of the bed body. In the bed with a load detection function according to any one of claims 1 to 8;
A bed with a load detection function, wherein the pair of fulcrum receiving areas in the load cell are respectively fitted in fixed portions in the bed body. In the bed with a load detection function according to any one of claims 1 to 8;
A bed with a load detection function, wherein the pair of fulcrum receiving areas in the load cell are each configured by an attachment hole for supporting a base at a fixed part in the bed body. In the bed with a load detection function according to any one of claims 1 to 11,
A bed with a load detection function, wherein the base of the load cell is interposed in the middle of a connection support portion in the bed body. In the bed with a load detection function according to claim 12;
The connection support part includes an elevating link mechanism that elevates and lowers the bed surface forming part,
A bed with a load detection function, wherein a base of the load cell is incorporated in the lifting link mechanism. In the bed with a load detection function according to claim 13;
In addition to the elevating link mechanism, the connection support portion includes a lower frame supported via the legs above the installation surface,
The elevating link mechanism has at least a first arm and a second arm as an arm connecting the bed surface forming portion and the lower arm, and the first arm is configured to have the bed surface. It is connected to the forming portion side, the second arm is connected to the lower frame side, and the base of the load cell is interposed between the bed surface forming portion and the lower arm. Bed with load detection function. In the bed with a load detection function according to claim 14;
The bed surface forming part has a bed and an upper frame that supports the bed,
The lifting link mechanism includes at least a first arm and a second arm as an arm connecting the upper frame and the lower arm, and the first arm is provided on the upper frame. With the load detection function, the second arm is connected to the lower frame side, and the base of the load cell is interposed between the upper frame and the lower arm. bed. In the bed with a load detection function according to claim 15,
One of the upper arm and the lower arm is provided with a support shaft at the end of the load cell on the side where the base is located, and either one of the load receiving part and the load transmitting part on the base A bed with a load detection function, wherein a bearing portion for receiving the support shaft is formed on one side. In the bed with a load detection function according to claim 16;
The bed with a load detection function, wherein the load transmitting portion in the base of the load cell is an attachment portion attached to the other arm of the upper arm and the lower arm. The bed with a load detection function according to claim 17,
A hollow cylinder portion is formed at an end of the other arm on the substrate side, and the attachment portion of the substrate is inserted into the hollow cylinder portion, and the attachment portion is fixed to the hollow cylinder portion. A bed with a load detection function. In the bed with a load detection function according to any one of claims 1 to 11,
A bed with a load detection function, wherein the base of the load cell is interposed between the bed surface forming part and the connection support part. In the bed with a load detection function according to any one of claims 1 to 11,
A bed with a load detection function, wherein a base of the load cell is interposed between the connection support portion and the leg portion. In the bed with a load detection function according to any one of claims 1 to 11,
A bed with a load detection function, wherein a base of the load cell is incorporated in the leg portion. A bed surface forming portion that forms a bed surface, a leg portion that is in contact with an installation surface on which the bed body is to be installed, and a bed surface forming portion and a leg portion so that the bed surface forming portion is located above the installation surface. Measuring the change in the load applied to the bed body by attaching to a bed body having a connection support part that connects between and transmits the load from the bed surface forming part toward the leg part, In the load detector for detecting the state of the user on the bed surface of the bed body,
A load cell having a base that receives a load from the bed surface forming portion side and a strain sensor attached to the base to detect strain of the base;
The base body includes a load receiving beam portion having a load receiving region and a pair of fulcrum receiving regions, a pair of operating arm portions projecting from different positions in the load receiving beam portion, and a tip side portion of the pair of operating arm portions The load receiving beam portion, the pair of operating arm portions and the connecting portion are configured so as to continuously surround the hollow portion as a whole,
The load receiving area is formed at a position corresponding to a reference plane crossing a straight line connecting the pair of fulcrum receiving areas in the middle of the pair of fulcrum receiving areas, and the load receiving area is along the reference plane Further, one of the pair of operating arm portions protrudes from a side where one of the pair of fulcrum receiving regions is located with respect to the reference plane in the load receiving beam portion. And the other of the pair of operating arm portions is formed so as to protrude from the side where the other fulcrum region of the pair of fulcrum receiving regions is located with respect to the reference plane in the load receiving beam portion. And
The strain sensor is attached to at least one of the pair of operating arm portions, and applies a load along the reference plane to the load receiving region in a state where the pair of fulcrum receiving regions are supported. At least one of the operating arm portions is elastically deformed, and the strain sensor is configured to detect strain of the elastic deformation,
In addition, the load is received from the bed surface forming portion side at any part of the load transmission path from the bed surface forming portion to the legs through the connection support portion in the bed body, and the load is transferred to the installation surface side. A bed load detector, characterized in that the base is attached to a transmitting part so as to be exchangeable with parts of the bed main body.

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