Patent ID: 12193980

DESCRIPTION OF EMBODIMENTS

Embodiments

A bed BD, a support structure100, and a load sensor kit (fixing member) according to an embodiment of the present invention will be described with reference toFIG.1toFIG.8.

As illustrated inFIG.1(a)andFIG.1(b), the bed BD mainly includes the support structure100including a lower mechanism10, an upper mechanism20, and a raising/lowering mechanism30, and a bed plate BP, a headboard HB, a footboard FB, and a pair of bed rails BR attached to the upper mechanism20of the support structure100.

In the following description, a longitudinal direction of the bed BD is referred to as a vertical direction of the bed BD and the support structure100, and a width direction of the bed BD is referred to as a horizontal direction of the bed BD and the support structure100. In the vertical direction, a side where the headboard HB is positioned is referred to as a head side, and a side where the footboard FB is positioned is referred to as a leg side. In the horizontal direction, a left side and a right side when the head side is viewed from the leg side in the vertical direction are referred to as a left side and a right side, respectively. A direction orthogonal to the vertical direction and the horizontal direction is referred to as an up-down direction.

As illustrated inFIG.2(a), the lower mechanism10mainly includes a lower frame (base frame)11, sliding brackets121,122, fixed brackets131,132, an actuator support beam14, and four caster parts15.

The lower frame11is a frame-shaped member having a rectangular shape in plan view, and includes a first portion111and a second portion112extending in the vertical direction of the support structure100, and a third portion113and a fourth portion114extending in the horizontal direction of the support structure100. Each of the first portion111to the fourth portion114is an elongated member having a rectangular cross section.

The sliding bracket121is an elongated member and, as illustrated inFIG.3(a), has a shape of an upper plate part121a, a lower plate part121b, and a vertical plate part121c, each being an elongated flat plate, coupled in a C-shape (U-shape) as viewed in the elongated direction. A size of the upper plate part121ain the elongated direction is smaller than sizes of the lower plate part121band the vertical plate part121cin the elongated direction.

The sliding bracket122is also an elongated member and, as illustrated inFIG.3(b), has a shape of an upper plate part122a, a lower plate part122b, and a vertical plate part122c, each being an elongated flat plate, coupled in a C-shape (U-shape) as viewed in the elongated direction. A size of the upper plate part122ain the elongated direction is smaller than sizes of the lower plate part122band the vertical plate part122cin the elongated direction.

The sliding bracket121and the sliding bracket122are mirror-symmetrical with respect to a plane parallel to the vertical plate parts121c,122c.

The sliding brackets121,122are attached to the lower frame11at the head side of a central part of the support structure100in the vertical direction. The sliding brackets121,122are fixed to the first portion111and the second portion112, respectively, and thus the elongated direction of the sliding brackets121,122coincides with the vertical direction of the support structure100. Specifically, an outer surface of the vertical plate part121cof the sliding bracket121abuts against and is welded to an inner side surface111iof the first portion111, and an outer surface of the vertical plate part122cof the sliding bracket122abuts against and is welded to an inner side surface112iof the second portion112.

As illustrated inFIG.4, the fixed bracket131includes a pair of flat plate parts131aopposing each other, and a curved plate part131bcurved in an arc shape about an axis131xand connecting lower end parts of the pair of flat plate parts131a. The fixed bracket13is substantially U-shaped as viewed in the direction of the axis131x. Similarly, the fixed bracket132includes a pair of flat plate parts132aopposing each other, and a curved plate part132bcurved in an arc shape about an axis132xand connecting lower end parts of the pair of flat plate parts132a. The fixed bracket132is substantially U-shaped as viewed in the direction of the axis132x.

The fixed brackets131,132are attached to the lower frame11at positions on the leg side of the central part of the support structure100in the vertical direction. The fixed bracket131is fixed to the inner side surface111iof the first portion111by welding with the axis131xaligned with the horizontal direction of the support structure100. The fixed bracket132is fixed to the inner side surface112iof the second portion112by welding with the axis132xaligned with the horizontal direction of the support structure100.

The actuator support beam14is an elongated member having a circular cross section and extending in the horizontal direction of the support structure100. A left end part of the actuator support beam14is fixed to the first portion111of the lower frame11at the head side of the sliding bracket121. A right end part of the actuator support beam14is fixed to the second portion112of the lower frame11at the head side of the sliding bracket122.

One caster part15is provided at each of four corners of the lower frame11. As illustrated inFIG.1(a), each of the four caster parts15includes a wheel support part WS attached to the lower frame11rotatably about a vertical axis, and a wheel W attached to the wheel support part WS rotatably about a horizontal axis.

As illustrated inFIG.2(c), the upper mechanism20mainly includes an upper frame (center frame)21, sliding brackets221,222, fixed brackets231,232, and a plurality of load sensors for attaching the sliding brackets221,222and the fixed brackets231,232to the upper frame21.

The upper frame21is a frame-shaped member having a rectangular shape in plan view, and includes a first portion211and a second portion212extending in the vertical direction of the support structure100, and a third portion213and a fourth portion214extending in the horizontal direction of the support structure100. Each of the first portion211to the fourth portion214is an elongated member having a rectangular cross section.

The sliding bracket (supported member)221is an elongated member and, as illustrated inFIG.5(a), has a shape of an upper plate part221a, a lower plate part221b, and a vertical plate part221c, each being an elongated flat plate, coupled in a C-shape (U-shape) as viewed in the elongated direction. A size of the lower plate part221bin the elongated direction is smaller than sizes of the upper plate part221aand the vertical plate part221cin the elongated direction. Therefore, in the vicinity of one end part of the upper plate part221ain the elongated direction, the lower plate part221bopposing the upper plate part221ais not present.

The sliding bracket (supported member)222is also an elongated member and, as illustrated inFIG.5(b), has a shape of an upper plate part222a, a lower plate part222b, and a vertical plate part222c, each being an elongated flat plate, coupled in a C-shape (U-shape) as viewed in the elongated direction. A size of the lower plate part222bin the elongated direction is smaller than sizes of the upper plate part222aand the vertical plate part222cin the elongated direction. Therefore, in the vicinity of one end part of the upper plate part222ain the elongated direction, the lower plate part222bopposing the upper plate part222ais not present. The sliding bracket221and the sliding bracket222are mirror-symmetrical with respect to a plane parallel to the vertical plate parts221c,222c.

As illustrated inFIG.2(c),FIG.6(a), andFIG.6(b), the sliding bracket221is attached to the first portion211of the upper frame21by four load sensors (attachment tools) S11, S12, S13, S14at the head side of the central part of the support structure100in the vertical direction. Each of the load sensors S11to S14includes a flexure element SB having a beam shape and a strain gauge SG adhered to the flexure element SB.

The sliding bracket221is attached to the upper frame21using the four load sensors S11to S14specifically as follows.

The sliding bracket221is disposed with the elongated direction of the sliding bracket221aligned with the vertical direction of the support structure100(that is, the longitudinal direction of the bed BD). In this state, an upper surface of the first portion211of the upper frame21and an upper surface of the upper plate part221aare flush, and a lower surface of the first portion211of the upper frame21and a lower surface of the lower plate part221bare flush.

The four load sensors S11, S12, S13, S14are respectively provided at the sliding bracket221at an upper side of one end side in the elongated direction, a lower side of one end side in the elongated direction, an upper side of the other end side in the elongated direction, and a lower side of the other end side in the elongated direction.

One end of the flexure element SB of the load sensor S11is fixed to the upper plate part221aat one end side of the sliding bracket221in the elongated direction, and the other end is fixed to the upper surface of the first portion211. One end of the flexure element SB of the load sensor S12is fixed to the lower plate part221bat one end side of the sliding bracket221in the elongated direction, and the other end is fixed to the lower surface of the first portion211. One end of the flexure element SB of the load sensor S13is fixed to the upper plate part221aat the other end side of the sliding bracket221in the elongated direction, and the other end is fixed to the upper surface of the first portion211. One end of the flexure element SB of the load sensor S14is fixed to the lower plate part221bat the other end side of the sliding bracket221in the elongated direction, and the other end is fixed to the lower surface of the first portion211.

In this state, the inner side surface211iof the first portion211and the vertical plate part221care disposed parallel to each other with a gap in the horizontal direction. The gap may be, for example, about 5 mm to 15 mm.

The sliding bracket222is also, by the same mode as the mode of the sliding bracket221, attached to the second portion212of the upper frame21by the four load sensors S11, S12, S13, S14at the head side of the central part of the support structure100in the vertical direction.

As illustrated inFIG.7, the fixed bracket231(secondary supported member) includes a pair of flat plate parts231aopposing each other, and a curved plate part231bcurved in an arc shape about an axis231xand connecting upper end parts of the pair of flat plate parts231a. The fixed bracket231is substantially U-shaped as viewed in the direction of the axis231x. Similarly, the fixed bracket (secondary supported member)232also includes a pair of flat plate parts232aopposing each other, and a curved plate part232bcurved in an arc shape about an axis232xand connecting upper end parts of the pair of flat plate parts232a. The fixed bracket232is substantially U-shaped as viewed in the direction of the axis232x.

As illustrated inFIG.2(c),FIG.8(a), andFIG.8(b), the fixed bracket231is attached to the first portion211of the upper frame21via two couplers24and four load sensors (secondary attachment tools) S21, S22, S23, S24at the leg side of the central part of the bed BD in the longitudinal direction.

Each of the two couplers24is a member having a C-shape (U-shape) in a side view and including an upper plate part24a, a lower plate part24bopposing the upper plate part24a, and a vertical plate part24cconnecting the upper plate part24aand the lower plate part24b.

Each of the four load sensors S21to S24has the same structure as the structure of each of the load sensors S11to S14and includes the flexure element SB having a beam shape and the strain gauge SG adhered to the flexure element SB.

The fixed bracket231is attached to the upper frame21using the two couplers24and the four load sensors S21to S24specifically as follows.

Outer surfaces of the vertical plate parts24cof the couplers24abut against and are fixed to respective outer surfaces of the pair of flat plate parts231aof the fixed bracket231. The fixed bracket231and the two couplers24are disposed with the curved plate part231bof the fixed bracket231protruding upward. In this state, the upper surface of the first portion211of the upper frame21and upper surfaces of the upper plate parts24aof the two couplers24are flush, and the lower surface of the first portion211of the upper bracket21and lower surfaces of the lower plate parts24bof the two couplers24are flush.

The four load sensors S21, S22, S23, S24are respectively provided at an upper side and a lower side of one coupler24and at an upper side and a lower side of the other coupler24.

One end of the flexure element SB of the load sensor S21is fixed to the upper plate part24aof one coupler24, and the other end is fixed to the upper surface of the first portion211. One end of the flexure element SB of the load sensor S22is fixed to the lower plate part24bof one coupler24, and the other end is fixed to the lower surface of the first portion211. One end of the flexure element SB of the load sensor S23is fixed to the upper plate part24aof the other coupler24, and the other end is fixed to the upper surface of the first portion211. One end of the flexure element SB of the load sensor S24is fixed to the lower plate part24bof the other coupler24, and the other end is fixed to the lower surface of the first portion211.

In this state, the inner side surface211iof the first portion211and the fixed bracket231are disposed parallel to each other with a gap in the horizontal direction. The gap may be, for example, about 5 mm to 15 mm.

As with the fixed bracket231, the fixed bracket232is also attached to the second portion212of the upper frame21via the two couplers24and the four load sensors S21, S22, S23, S24at the leg side of the central part of the support structure100in the vertical direction.

As illustrated inFIG.2(b), the raising/lowering mechanism30mainly includes an inner arm part31, an outer arm part32, and an actuator33.

As illustrated inFIG.1(a),FIG.1(b), andFIG.2(b), the inner arm part31includes a lower shaft311(below an upper shaft322(described below) of the outer arm part32inFIG.2(b); not illustrated), an upper shaft312, a pair of inner arms313, and an actuator coupling beam314.

The lower shaft311is an elongated member having a circular cross section and extending in the horizontal direction of the support structure100. A left end part of the lower shaft311abuts against an upper surface of the curved plate part131bof the fixed bracket131fixed to the first portion111of the lower frame11, and is supported by the fixed bracket131. A right end part of the lower shaft311abuts against an upper surface of a curved plate part132bof the fixed bracket132fixed to the second portion112of the lower frame11, and is supported by the fixed bracket132.

The upper shaft (support shaft)312is an elongated member having a circular cross section and extending in the horizontal direction of the support structure100. A left end part of the upper shaft312abuts against a lower surface of the upper plate part221aof the sliding bracket221fixed to the first portion211of the upper frame21and supports the upper mechanism20via the sliding bracket221. A right end part of the upper shaft312abuts against a lower surface of the upper plate part222aof the sliding bracket222fixed to the second portion212of the upper frame21and supports the upper mechanism20via the sliding bracket222.

Each of the pair of inner arms313is an elongated member having a rectangular cross section. One of the pair of inner arms313is connected to the vicinity of the left end part of the lower shaft311at one end part, and connected to the vicinity of the left end part of the upper shaft312at the other end part. The other of the pair of inner arms313is connected to the vicinity of the right end part of the lower shaft311at one end part, and connected to the vicinity of the right end part of the upper shaft312at the other end part.

The actuator coupling beam314is an elongated member having a circular cross section and extending in the horizontal direction of the support structure100. A left end part of the actuator coupling beam314is connected to one of the pair of inner arms313at a substantially intermediate part between a central part of the inner arm313in the longitudinal direction and a connection part between the inner arm313and the upper shaft312. A right end part of the actuator coupling beam314is connected to the other of the pair of inner arms313at a substantially intermediate part between a central part of the inner arm313in the longitudinal direction and a connection part between the inner arm313and the upper shaft312.

The outer arm part32includes a lower shaft321(below the upper shaft312(described below) of the inner arm part31inFIG.2(b); not illustrated), the upper shaft322, and a pair of outer arms323.

The lower shaft321is an elongated member having a circular cross section and extending in the horizontal direction of the support structure100. A left end part of the lower shaft321abuts against the lower plate part121bof the sliding bracket121fixed to the first portion111of the lower frame11, and is supported by the sliding bracket121. A right end part of the lower shaft321abuts against an upper surface of the lower plate part122bof the sliding bracket122fixed to the second portion112of the lower frame11, and is supported by the sliding bracket122.

The upper shaft (secondary support shaft)322is an elongated member having a circular cross section and extending in the horizontal direction of the support structure100. A left end part of the upper shaft322abuts against a lower surface of the curved plate part231bof the fixed bracket231fixed to the first portion211of the upper frame21, and supports the upper mechanism20via the fixed bracket231. A right end part of the upper shaft322abuts against a lower surface of the curved plate part232bof the fixed bracket232fixed to the second portion212of the upper frame21, and supports the upper mechanism20via the fixed bracket232.

Each of the pair of outer arms323is an elongated member having a rectangular cross section. One of the pair of outer arms323is connected to the vicinity of the left end part of the lower shaft321at one end part, and connected to the vicinity of the left end part of the upper shaft322at the other end part. The other of the pair of outer arms323is connected to the vicinity of the right end part of the lower shaft321at one end part, and connected to the vicinity of the right end part of the upper shaft322at the other end part.

The inner arm part31and the outer arm part32are pivotally coupled to each other. Specifically, in the horizontal direction of the support structure100, the inner arm313and the outer arm323positioned at the left side are pivotally coupled by a horizontal pin P at respective central parts in the longitudinal direction, and the inner arm313and the outer arm323positioned at the right side are pivotally coupled by the horizontal pin P at respective central parts in the longitudinal direction.

The actuator33includes a cylinder331and a rod332extended and contracted by the cylinder331. The actuator33may be, for example, an electric actuator, a hydraulic actuator, or a pneumatic actuator.

The cylinder331is pivotally supported by the actuator support beam14of the lower mechanism10. A distal end part of the rod332is pivotally coupled to the actuator coupling beam314of the inner arm part31.

Each of the bed plate BP, the headboard HB, the footboard FB, and the pair of bed rails BR is detachably attached to the upper frame21via an attachment part (not illustrated) provided at the upper frame21of the upper mechanism20(FIG.1(a)andFIG.1(b)).

In the present embodiment, a total of eight load sensors S11to S14for fixing the sliding brackets221,222to the upper frame21and a total of eight load sensors S21to S24for fixing the fixed brackets231,232to the upper frame21constitute a load sensor kit (fixing member).

Raising/Lowering of Upper Mechanism20

In the support mechanism100having the structure described above, the upper mechanism20is raised and lowered as follows.

When the upper mechanism20is in a lowered position (lowest position possible of the upper mechanism20;FIG.1(a)), the rod332of the actuator33is mostly accommodated in an interior of the cylinder331. When the actuator33is driven in this state, the rod332is pushed out from the cylinder331, and the rod332presses the actuator coupling beam314of the inner arm part31obliquely upward.

As a result, the pair of inner arms313rotate about the lower shaft311supported by the fixed brackets131,132of the lower mechanism10, and the upper shaft312sliding in the sliding brackets221,222of the upper mechanism20presses the sliding brackets221,222upward.

At the same time, the pair of outer arms323pivotally coupled to the pair of inner arms313rotate about the upper shaft322supported by the fixed brackets231,232of the upper mechanism20, and the lower shaft321sliding in the sliding brackets121,122of the lower mechanism10presses the sliding brackets121,122downward. Then, in accordance with this, the upper shaft322presses the fixed brackets231,232of the upper mechanism20upward.

In this way, as the rod332is pushed out by the cylinder331, the pair of inner arms313and the pair of outer arms323pivot, and the upper mechanism20rises. With the rod332fully pushed out, the upper mechanism20reaches a raised position (highest position possible of the upper mechanism20;FIG.1(b)). On the other hand, as the rod332is accommodated in the cylinder331, the upper mechanism20lowers.

Here, as illustrated inFIG.1(a)andFIG.1(b), the load sensors S11to S14are provided outside a movable range of the upper shaft312of the sliding brackets221,222. That is, the load sensors S11, S12attached to the sliding brackets221,222at positions on the head side of the support structure100are disposed at the head side of a center of the upper shaft312when the upper mechanism20is in the lowered position (that is, points where the loads of the brackets221,222act on the load sensors S11, S12are positioned at the head side of the center of the upper shaft312). Further, the load sensors S13, S14attached to the sliding brackets221,222at positions on the leg side of the support structure100are disposed at the leg side of the center of the upper shaft312when the upper mechanism20is in a raised position (that is, points where the loads of the brackets221,222act on the load sensors S13, S14are positioned at the leg side of the center of the upper shaft312).

By arranging the load sensors S11to S14in this manner, it is possible to detect the load with high accuracy even when the upper mechanism20is in any position (height) including the lowered position and the raised position. The reason is as follows.

In the detection of the load of a subject on the bed BD using the load sensors S11to S14, the detected values of the load sensors S11to S14are added together (details described below). At this time, when the detected values of the load sensors S11to S14are added with the load sensors S11to S14being disposed only at one side of the upper shaft312in the vertical direction, influences of placement deviation errors (errors occurring in the detected values of the load sensors according to distances between the load sensors and the subject) in the respective load sensors S11to S14are also added, making the value greater.

In response, in the present embodiment, when the distances between the upper shaft312and the load sensors S11, S12increase with the movement of the upper shaft312, increasing the placement deviation errors of the load sensors S11, S12, the distances between the upper shaft312and the load sensors S13, S14decrease, decreasing the placement deviation errors of the load sensors S13, S14. On the contrary, when the distances between the upper shaft312and the load sensors S13, S14increase, increasing the placement deviation errors of the load sensors S13, S14, the distances between the upper shaft312and the load sensors S11, S12decrease, decreasing the placement deviation errors of the load sensors S11, S12. Thus, by providing the load sensors S11to S14outside the movable range of the upper shaft312of the sliding brackets221,222, the load sensors are disposed at both sides of the upper shaft312regardless of the position of the upper shaft312, and the influences of the placement deviation errors are canceled and suppressed.

Load Measurement of Subject S on Bed BD

In the bed BD having the structure described above, the load of a subject S on the bed BD is measured (detected) as follows.

As illustrated inFIG.2(c), the load sensors S11to S14fixing the sliding bracket221to the upper frame21constitute a first load detection unit LS1. A calculation unit of the support structure100(not illustrated; attached to the upper frame21, for example) acquires an output value of the first load detection unit LS1by adding the output values of the load sensors S11to S14of the first load detection unit LS1.

Similarly, the load sensors S11to S14fixing the sliding bracket222to the upper frame21constitute a second load detection unit LS2, and the calculation unit acquires an output value of the second load detection unit LS2by adding the output values of the load sensors S11to S14of the second load detection unit LS2. The load sensors S21to S24fixing the fixed bracket231to the upper frame21constitute a third load detection unit LS3, and the calculation unit acquires an output value of the third load detection unit LS3by adding the output values of the load sensors S21to S24of the third load detection unit LS3. The load sensors S21to S24fixing the fixed bracket232to the upper frame21constitute a fourth load detection unit LS4, and the calculation unit acquires an output value of the fourth load detection unit LS4by adding the output values of the load sensors S21to S24of the fourth load detection unit LS4.

For example, the calculation unit calculates a weight of the subject on the bed BD by adding the output values of the first load detection unit LS1to the fourth load detection unit LS4. In addition, for example, a center-of-gravity position of the subject on the bed BD is calculated using the output values of the first load detection unit LS1to the fourth load detection unit LS4.

The advantageous effects of this support structure100of the present embodiment are summarized below.

In the support structure100of the present embodiment, the sliding brackets221,222and the fixed brackets231,232are fixed to the upper frame21using the load sensors S11to S14and S21to S24, and thus a load detection unit detecting the load of the subject on the bed is built into the structure supporting the bed. Accordingly, the support structure for a bed having a load detection function can be easily manufactured without requiring the manufacture of a bracket or a load sensor having a special structure.

In the support structure100of the present embodiment, the brackets using the load sensors S11to S14and S21to S24are fixed to the frame at the upper mechanism20, not the lower mechanism10. Accordingly, the entire load of the subject on the bed plate BP of the bed BD is transmitted to any one of the load sensors S11to S14and S21to S24, making it possible to detect the load of the subject with high accuracy. If the brackets using the load sensors S11to S14and S21to S24were fixed to the frame at the lower mechanism10, it would be difficult to detect the load of the subject with high accuracy. This is because a lower part of the cylinder331of the actuator33is supported by the lower mechanism10, and a part of the load of the subject on the bed plate BP applied to the upper mechanism20is transmitted to the lower mechanism10via the actuator33.

In the support structure100of the present embodiment, in the sliding brackets121,122, the sizes of the upper plate parts121a,122ain the longitudinal direction are smaller than the sizes of the lower plate parts121b,122bin the longitudinal direction. Further, in the sliding brackets221,222, the sizes of the lower plate parts221b,222b(the upper surface is a “second surface” in the present invention) in the longitudinal direction are smaller than the sizes of the upper plate parts221a,222a(the lower surface is a “first surface” in the present invention) in the longitudinal direction. Accordingly, in the manufacture of the support structure100or the like, the lower shaft321and the upper shaft312of the raising/lowering mechanism30can be easily arranged at the inside of the brackets via regions (introduction ports) of the sliding brackets121,122,221,222where the upper plate parts121a,122aand the lower plate parts221b,222bdo not exist.

Note that, in the present embodiment, the regions (introduction ports) where the upper plate parts121a,122aand the lower plate parts221b,222bdo not exist are positioned at the leg side of the support structure100in the vertical direction, but the regions (introduction ports) where the upper plate parts121a,122aand the lower plate parts221b,222bdo not exist may be positioned at the head side.

In addition, as described above, because the load sensors S11to S14are provided outside the movable range of the upper shaft312, it is possible to detect the load of the subject with high accuracy, regardless of the position of the upper shaft312.

According to the load sensor kit of the present embodiment, the same effects as the effects described above can be obtained.

Modifications

In the embodiment described above, the following modified examples can also be used.

In the embodiment described above, the sliding brackets221,222and the fixed brackets231,232are all attached to the upper frame21using the load sensors, but the attachment is not limited to this. At least one of the sliding bracket221or222or at least one of the fixed bracket231or232may be attached to the upper frame21using the load sensors while the other brackets may be fixed to the upper frame21in a conventional manner, such as welding, for example.

In the embodiment described above, each of the sliding brackets221,222and the fixed brackets231,232is attached to the upper frame21using four load sensors, but the number is not limited to this. The sliding brackets221,222and the fixed brackets231,232may be attached to the upper frame21using any number of load sensors.

Specifically, for example, the sliding bracket221may be attached to the upper frame21by the two load sensors of the load sensor S11at an upper side of one end side and the load sensor S13at an upper side of the other end side of the sliding bracket221, or may be attached by the two load sensors of the load sensor S12at a lower side of one end side and the load sensor S14at a lower side of the other end side of the sliding bracket221. Alternatively, the sliding bracket221may be fixed to the upper frame21by a single load sensor disposed at an upper side or a lower side of a central part of the sliding bracket221in the longitudinal direction.

In the embodiment described above, the load sensor kit includes a total of 16 load sensors, but the number is not limited to this. The number of load sensors (attachment tools, fixing tools) included in the load sensor kit may be changed as desired in accordance with the number used for attaching the brackets to the upper frame21.

In the embodiment described above, stop plates extending in a plane orthogonal to the longitudinal direction of the sliding brackets121,122,221,222may be provided at end parts of the sliding brackets121,122,221,222in the longitudinal direction.

In the embodiment described above, rollers may be provided at both end parts of the upper shaft312, and the rollers may be rolled in the sliding brackets221,222.

In the embodiment described above, the fixed brackets231,232are attached to the upper frame21by the couplers24, but attachment is not limited to this. For example, end parts of the flexure elements SB of each load sensor S21to S24may be directly attached to the flat plate parts231a,232aof the fixed brackets231,232. In the present invention, the “flexure element fixed to the secondary supported member” includes both a mode with the flexure element directly fixed to the secondary support member and a mode with the flexure element fixed to the secondary support member via a member such as the coupler24.

In the embodiment described above, the configurations of the load sensors S11to S14and S21to S24can be changed as desired. Specifically, for example, a flexure element having a plate shape may be provided instead of the flexure element SB having a beam shape. Further, the flexure elements of the plurality of load sensors may be integrally formed. For example, as illustrated inFIG.9(a)andFIG.9(b), the flexure elements of the load sensor S11and the load sensor S13may be flexure elements SB1, each being a flat plate having a C-shape (U-shape) in plan view, and the flexure elements of the load sensor S12and the load sensor S14may be flexure elements SB2, each being a flat plate having a C-shape (U-shape) in plan view. Similarly, although not illustrated, the flexure elements of the load sensor S21and the load sensor S23may be flexure elements being flat plates having a C-shape (U-shape) in plan view, and the flexure elements of the load sensor S22and the load sensor S24may be flexure elements being flat plates having a C-shape (U-shape) in plan view. This makes it possible to suppress rotation of the sliding brackets221,222and the fixed brackets231,232attributable to a force in the vertical direction (longitudinal direction) of the bed BD being applied to the upper frame21.

As long as the features of the present invention are maintained, the present invention is not limited to the embodiments described above, and other forms considered within the scope of the technical concept of the present invention are also included within the scope of the present invention.

REFERENCE SIGNS LIST

10Lower mechanism;11Lower frame;121,122,221,222Sliding bracket;131,132,231,232Fixed bracket;20Upper mechanism;21Upper frame;30Raising/Lowering mechanism;311,321Lower shaft;312,322Upper shaft;313Inner arm;323Outer arm;33Actuator; BD Bed