Bed lifting device

Abstract

Provided is a bed lifting device that suppresses a failure of a bed lifting mechanism caused by impact transmitted from a mattress in use. 【Solution means】The bed lifting device 101 includes a support portion 111 that is attached to the lower portion of the bed 11 and supports the bed, and a base portion 131 that can be grounded to the floor F, and the support portion and the base portion are connected by a lifting mechanism 151. The lifting mechanism constitutes a parallel link mechanism 154 that connects the support portion and the base portion by a pair of left and right links 152 and 153 provided on the head side HS and the foot side FS, respectively, and is given a driving force from the drive portion 201 to change the opposing interval between the support portion and the base portion. The opposing interval is variable between a first interval in which the base portion does not contact the floor and a second interval in which the bed is lifted from the floor. The drive portion is controlled so that the opposing interval is selectively switched between the first interval and the second interval.

Description

Technical Field

[0001] The present disclosure relates to a bed lifting device.

Background Art

[0002] Some beds are of the elevating type.

[0003] For example, Patent Document 1 discloses a device in which a movable frame (5) that supports a bedding or an examination table is vertically movable substantially in parallel with respect to a fixed-side frame (1) installed on the floor via a telescopic link mechanism (2, 3) (see paragraph

[0015] of Patent Document 1 and the drawings). The link mechanism is driven by a telescopic actuator (electric motor, fluid pressure cylinder) to raise and lower the movable frame.

[0004] A bed lifting device of this type is also disclosed in Patent Document 2. As shown in FIG. 1 of Patent Document 2, the bed lifting device has a base plate (102), a lifting assembly (110), a bed frame (130), and a bed (10) located on the bed frame, and enables manual lifting and lowering of the bed (see lines 57 to 14 in column 4 of Patent Document 2).

[0005] Regarding the purpose of raising and lowering the bed, there is no particular description in Patent Document 1. In contrast, Patent Document 2 mentions the physical burden on the person making the bed (see lines 19 to 37 in column 1 of Patent Document 2). As a document that mentions a similar purpose, there is Patent Document 3 (see paragraphs

[0002] and

[0003] of Patent Document 3).

[0006] Patent Document 3 discloses a bed lifting device that is disposed and used between the floor and the bed (see paragraphs

[0037] -

[0048] of Patent Document 3). The difference between this device and the devices described in Patent Documents 1 and 2 is that it is provided separately and independently from the bed (see paragraphs

[0048] and

[0076] of Patent Document 3).

[0007] More specifically, the bed lifting device described in Patent Document 3 is configured such that a support frame (14) is provided to be vertically movable with respect to a base frame (12) disposed on a floor (F) via a pantograph-type linkage (16). The linkage is driven by an electric stepping motor (28) to raise and lower the support frame, thereby lifting the bed (see paragraphs

[0037] -

[0048] of Patent Document 3 and FIGS. 13-15).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] In beds with a lifting device as described in Patent Documents 1 and 2, the impact from the mattress during use is transmitted to the lifting device, that is, the link mechanism and the actuator of Patent Document 1 and the lifting assembly of Patent Document 2, which may cause malfunctions.

[0010] Although the bed lifting device described in Patent Document 3 is provided separately and independently from the bed, during normal use of the bed, the support frame contacts the bed (bed base B) and supports the bed. This is clear from the description "the lower side of the bed is stationary on the land 40 and is supported during use" and the description "the support frame 14 engaged with the lower side of the bed B" (see paragraphs

[0049] and

[0065] of Patent Document 3).

[0011] Therefore, even in the bed lifting device described in Patent Document 3, the impact from the mattress during use is transmitted to the pantograph type linkage and the electric stepping motor, which may cause a failure.

[0012] An object of the present disclosure is to prevent a failure of a bed lifting mechanism caused by the transmission of an impact from a mattress during use.

Means for Solving the Problems

[0013] One aspect of the bed lifting device includes a support portion attached to the lower part of the bed to support the bed, a base portion that can be grounded to the floor, a lifting mechanism that variably connects the support portion and the base portion so that the opposing intervals therebetween can be freely changed, a drive portion that applies a driving force for changing the opposing intervals to the lifting mechanism, and a control portion that controls the drive portion. The lifting mechanism varies the opposing intervals between a first interval in which the base portion does not contact the floor and a second interval in which the bed is lifted from the floor, and the control portion controls the drive portion so that the opposing intervals are selectively switched between the first interval and the second interval.

Effects of the Invention

[0014] It is possible to prevent a failure of the bed lifting mechanism caused by the transmission of an impact from a mattress during use.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0016] The embodiments will be described with reference to the drawings according to the following items. 1. Bed 2. Bed lifting device (1) Overview (2) Configuration (a) Definition (i) Support part and base part (ii) Lifting mechanism (iii) Driving part (iv) Motion conversion part (v) Linkage mechanism (vi) Connection between the bed and the bed lifting device (vii) Foot switch (viii) Control unit (3)Function (A)Process of lifting the bed from the floor (B)Process of lowering the bed to the floor (C)Continuous operation of the lifting support part and the lowering support part (4)Function and effect (A)Basic function and effect (B)Gap with the floor (C)Stability (D)Height setting of the bed 3.Variation

[0017] 1.Bed As shown in FIG. 1, a bed 11 is installed on the floor F. The bed 11 is in a form where a mattress 51 is placed on a bed frame 31, and one end side in the longitudinal direction is defined as the head side HS, and the side opposite to one end is defined as the foot side FS. The head side HS is the side where the head of the user of the bed 11 is positioned, and the foot side FS is the side where the feet are positioned. The bed 11 is arranged with the head side HS close to the wall W and the foot side FS away from the wall W.

[0018] The bed frame 31 has legs 32 at the four corners and the central part. All five legs 32 are aligned to the same length, creating a space S between the floor F and the bed frame 31 by the length. Details of the bed frame 31 will be described later with reference to FIGS. 7 and 8.

[0019] The bed lifting device 101 of the present embodiment is attached to the lower part of the bed 11, more specifically, the lower part of the bed frame 31, and is arranged in the space S generated between the floor F and the bed frame 31. At this time, the bed lifting device 101 maintains a gap G with the surface of the floor F and is kept in a non-contact state with the floor F.

[0020] 2.Bed lifting device (1)Overview As shown in FIGS. 2(A) and 2(B), the bed lifting device 101 includes a support portion 111 and a base portion 131, and the support portion 111 and the base portion 131 are connected by a lifting mechanism 151. The support portion 111 is a member attached to the lower part of the bed frame 31 to support the bed 11. The base portion 131 is a member that can be installed on the floor F. The lifting mechanism 151 varies the opposing interval OD between the support portion 111 and the base portion 131.

[0021] The bed lifting device 101 transitions between the folded state shown in FIG. 2(A) and the raised state shown in FIG. 2(B) by the action of the lifting mechanism 151. In the present embodiment, the opposing interval OD when the bed lifting device 101 is folded is referred to as the first interval OD1, and the opposing interval OD when the bed lifting device 101 is raised is referred to as the second interval OD2.

[0022] As shown in FIGS. 1, 2(A), and 14(A), when the opposing interval OD becomes the first interval OD1 and the bed lifting device 101 is folded, the base portion 131 is kept in a state with a gap G from the floor F. At this time, the base portion 131 is provided with buffer legs E that exhibit a buffering action at the four corners, and the lower surface of the buffer legs E is at the lowest position. Therefore, the gap G is secured between the floor F and the lower surface of the buffer legs E.

[0023] When the bed lifting device 101 is raised, the base portion 131 first contacts the floor F (see FIG. 14(B)), and then the support portion 111 lifts the bed 11 from the floor F (see FIG. 14(C)). At this time, the opposing interval OD becomes the second interval OD2 (see FIG. 2(B)).

[0024] The second interval OD2 will be described in detail.

[0025] In this embodiment, the concept of the second interval OD2 means the facing interval OD by which the bed 11 can be lifted from the floor F beyond the state where the base 131 touches the floor F with the bed 11 touching the floor F (see Fig. 14(B)) (see Fig. 14(C)). As long as the bed 11 is lifted from the floor F, regardless of the degree of lifting, the facing interval OD between the support portion 111 and the base 131 at that time is the second interval OD2.

[0026] On the other hand, Figs. 2(B) and 14(C) show the state where the bed lifting device 101 is fully raised. At this time, the second interval OD2 is maximized and the bed 11 is lifted to the maximum extent. In this embodiment, the second interval OD2 when it is maximized is denoted as the second interval OD2max.

[0027] (2) Configuration Based on Figs. 2(A)(B) to Figs. 5(A)(B), the structure of the bed lifting device 101 will be described.

[0028] (a) Definition In this embodiment, the terms head side HS and foot side FS of the bed 11 are also applied as they are to the bed lifting device 101. That is, the head side HS of the bed 11 directly becomes the head side HS of the bed lifting device 101, and the foot side FS of the bed 11 directly becomes the foot side FS of the bed lifting device 101.

[0029] The longitudinal direction of the bed 11 and the bed lifting device 101 connecting the head side HS and the foot side FS is called the X direction, and the left - right direction of the bed 11 orthogonal to the X direction is called the Y direction. The Z direction is the vertical direction orthogonal to the floor F on which the bed 11 is installed.

[0030] Figs. 1, 2(A)(B) and 7 show the X direction and the Z direction by the symbols X and Z. Figs. 3 and 8 show the X direction and the Y direction by the symbols X and Y.

[0031] The bed lifting device 101 comprises a link device formed by combining a plurality of links with turning pairs. The turning pairs connect the individual links rotatably about an axis extending in the Y direction. In the present embodiment, the axis extending in the Y direction is referred to as the Y axis.

[0032] (a) Support part and base part As shown in FIGS. 2(A), (B) and 3, the support part 111 is a frame body 114 that connects both ends in the longitudinal direction (X direction) of a pair of left and right side members 112 by a pair of connecting members 113. The frame body 114 has a rectangular shape in plan view.

[0033] The side member 112 is manufactured by bending a flat plate made of, for example, metal so as to have a hollow shape with a rectangular cross-sectional shape. The connecting member 113 is, for example, a long and thin flat plate member made of metal. The pair of connecting members 113 are fixed to the upper surface of the side member 112, for example, by welding.

[0034] The length of the connecting member 113 is longer than the opposing interval in the Y direction of the pair of side members 112 and protrudes outward from the side member 112. Bolt holes 113a are provided at four protruding portions. The bolt holes 113a are holes for passing bolts (not shown) for fixing the support part 111 to the bed frame 31. The fixing of the support part 111 to the bed frame 31 will be described later with reference to FIGS. 7 and 8.

[0035] As shown in FIGS. 2(A), (B) and 3, the base part 131 is a frame body 134 that connects both end portions in the longitudinal direction (X direction) of a pair of left and right side members 132 by a pair of connecting members 133. The frame body 134 has a rectangular shape in plan view.

[0036] The side member 132 and the connecting member 133 are manufactured by bending a flat plate made of, for example, metal so as to have a hollow shape with a rectangular cross-sectional shape. The pair of connecting members 133 are fixed to both end portions of the pair of side members 132, for example, by welding.

[0037] A reinforcing member 135 is spanned across an intermediate portion of a pair of side members 132. The reinforcing member 135 is manufactured, for example, by bending a flat plate made of metal, for example, into an L-shaped cross section (see FIGS. 4(A)-(C) and FIGS. 5(A)(B)). The position where the reinforcing member 135 is spanned is a position on the X direction of the base 131, slightly closer to the foot side FS than the head side HS.

[0038] A support piece 136 is fixed to the reinforcing member 135 so as to protrude from the reinforcing member 135 toward the foot side FS. The support piece 136 is a metal member used for supporting a drive unit 201 (see FIGS. 3 and 5(B)) described later, and is fixed to the reinforcing member 135 by welding, for example. Support of the drive unit 201 by the support piece 136 and the drive unit 201 itself will be described later.

[0039] As another example, as shown in FIG. 6, the reinforcing member 135 may be a metal member having a rectangular cross section. As an example, the length in the X axis direction of the rectangular shape of the reinforcing member 135 is longer than the length in the Z axis direction. Also, the height of the reinforcing member 135, that is, the length in the Z direction, is lower than the height of the side member 132. As an example, the lower surface of the reinforcing member 135 is positioned in the same plane as the lower surface of the side member 132, and the upper surface of the reinforcing member 135 is positioned at a lower position than the plane including the upper surface of the reinforcing member 135.

[0040] A support piece 136 shown in FIG. 6 is fixed to the reinforcing member 135 shown in the same figure. The support piece 136 of this example has joint surfaces with respect to the reinforcing member 135 in the X axis direction and the Z axis direction, and is fixed to the upper surface and the side surface on the foot side FS of the reinforcing member 135 by welding, for example.

[0041] As described above, the base 131 is provided with buffer legs E at its four corners. The buffer legs E are attached to the lower surface of the connecting member 133.

[0042] When comparing the sizes of the support part 111 and the base part 131, in both the X direction and the Y direction, the base part 131 has larger dimensions than the support part 111. More specifically, as shown in FIG. 3, when the base part 131 and the support part 111 are overlapped with their center lines in the X direction aligned, with respect to a virtual vertical plane (hereinafter referred to as the "outer vertical plane") including the inner wall of the side member 132, a virtual vertical plane (hereinafter referred to as the "inner vertical plane") including the outer wall of the side member 112 is positioned inward, and the dimensional relationship is defined such that there is a gap between the outer vertical plane and the inner vertical plane.

[0043] (U) Lifting mechanism As shown in FIGS. 2(A), (B) and FIG. 3, the lifting mechanism 151 has a pair of left and right links 152, 153 that connect the support part 111 and the base part 131 to the head side HS and the foot side FS of the bed lifting device 101. The link 152 on the foot side FS and the link 153 on the head side HS have the same shape and size, and together with the support part 111 and the base part 131, they form a parallel link mechanism 154.

[0044] FIG. 4(A) is a cross-sectional view taken along the line A-A in FIG. 3, and FIG. 4(B) is a cross-sectional view taken along the line B-B in FIG. 3. The lines A-A and B-B are lines that take a cross-section between the above-mentioned outer vertical plane and the inner vertical plane. The line B-B takes a cross-section more inward, that is, on the center side of the bed lifting device 101, than the line A-A.

[0045] As shown in FIG. 4(A), at the position of the cross-sectional view along the line A-A, only the inner wall of one side member 132 of the base part 131, the L-shaped cross-section of the reinforcing member 135, and the support shaft A1 for attaching the links 152, 153 appear. On the other hand, at the position of the cross-sectional view along the line B-B, which is located more inward, as shown in FIG. 4(B), the two links 152, 153 appear. The links 152, 153 are rotatably connected at one end side by the support shaft A1 and rotatably attached to the support shaft A2 at the other end side. These support shafts A1, A2 extend in the Y-axis direction.

[0046] In FIGS. 4(A) and 4(B), the connecting member 113 of the support portion 111 that should originally appear is shown omitted.

[0047] In the present embodiment, the one located on the foot side FS is called the link 152, and the one located on the head side HS is called the link 153. Also, when the bed elevating device 101 is viewed in plan with the head side HS facing up, the one located on the left side is called the links 152L and 153L, and the one located on the right side is called the links 152R and 153R. Appearing in the cross-sectional view taken along line B-B shown in FIG. 4(B) are the links 152L and 153L.

[0048] FIG. 4(C) is a cross-sectional view taken along line C-C in FIG. 3. The line C-C is a line that takes a cross-section inside the side member 112 of the support portion 111, that is, on the center side of the bed elevating device 101. For this reason, in the cross-sectional view taken along line C-C, the side member 112 also appears. The links 152L and 153L are rotatably connected to the side member 112 via the support shaft A2.

[0049] In FIGS. 4(A) to 4(C), the structure on the left side of the bed elevating device 101 is shown. However, the parallel link mechanism 154 using the pair of left and right links 152 and 153 is symmetric about the left and right, and the right side has the same structure as the left side. Since the elevating mechanism 151 configured in this way is the parallel link mechanism 154, it is possible to vary the opposing interval OD between them while keeping the support portion 111 and the base portion 131 parallel.

[0050] (E) Driving portion FIG. 5(A) is a cross-sectional view taken along line D-D in FIG. 3, and FIG. 5(B) is a cross-sectional view taken along line E-E in FIG. 3.

[0051] As shown in FIGS. 3 and 5(B), the support portion 111 includes a drive portion 201 that applies a driving force to the elevating mechanism 151 and drives the elevating mechanism 151 so as to vary the opposing interval OD between the support portion 111 and the base portion 131. The drive portion 201 of the present embodiment is a linear actuator that linearly moves a rod 202. The linear actuator connects the rotating shaft of the motor M and the rod 202 via a coupling 203, converts the rotational motion of the rotating shaft into a linear motion, and transmits it to the rod 202 (see FIG. 12).

[0052] As an example, a motor M that can rotate its rotating shaft forward and backward is used. In this case, when the rotating shaft rotates in one direction, the rod 202 moves forward, and when it rotates in the opposite direction, the rod 202 moves backward. As another example, a selector (not shown) that switches the rotating shaft of a motor M that rotates only in one direction to be reversible may be provided in the coupling 203, for example, and the rod 202 may be alternatively reciprocated by controlling the selector.

[0053] (E) Motion conversion unit As described above, in the present embodiment, a linear actuator is used for the drive portion 201. Therefore, in order to move the elevating mechanism 151 so as to vary the opposing interval OD between the support portion 111 and the base portion 131, it is necessary to convert the linear motion of the rod 202 into the rotational motion of the pair of left and right links 152 and 153. To achieve this purpose, the elevating mechanism 151 includes a motion conversion unit 161.

[0054] As shown in FIGS. 3 and 5(B), the motion conversion unit 161 fixedly spans a bar 162 between a pair of left and right links 152L and 152R located on the foot side FS, and fixedly provides a drive piece 163 on the bar 162. The bar 162 is fixed at a position closer to the connection portion with the base portion 131 than the connection portion with the support portion 111 in the pair of links 152L and 152R. The drive piece 163 is provided in a shape that protrudes obliquely upward toward the support portion 111 and is provided at the center position of the bar 162.

[0055] The bar 162 is, for example, a pipe-shaped member made of metal, and is fixed to the inner wall portions of the pair of links 152L and 152R by welding. The drive piece 163 is, for example, a flat plate-shaped member made of metal, and is fixed to the bar 162 by welding.

[0056] The drive unit 201, which is a linear actuator, has a portion on the side opposite to the rod 202 rotatably attached to a reinforcing member 135 provided on the base 131. More specifically, the drive unit 201 is attached to a support piece 136 fixed to the reinforcing member 135. The drive unit 201 is attached to the support piece 136 so as to be rotatable about an axis in the Y-axis direction so as to undulate in the Z-axis direction.

[0057] Also in the embodiment shown in FIG. 6, the support structure of the drive unit 201 by the support piece 136 fixed to the reinforcing member 135 is common. It is also common that the drive unit 201 is attached to the support piece 136 so as to be rotatable about an axis in the Y-axis direction so as to undulate in the Z-axis direction.

[0058] The rod 202 of the drive unit 201 has its tip rotatably attached to the tip of the drive piece 163. More specifically, a support shaft A3 extending in the Y-axis direction is spanned between the pair of drive pieces 163. The tip of the rod 202 is rotatably attached to this support shaft A3. Therefore, the rotation of the rod 202 with respect to the drive piece 163 is also a rotation about the Y-axis.

[0059] In FIG. 5(B), when the rod 202 of the drive unit 201 advances in the direction in which it protrudes, a counterclockwise rotational force is applied to the drive piece 163. At this time, since the drive piece 163 is fixed to the bar 162 and the bar 162 is fixed to the link 152, the rotational force applied to the drive piece 163 is transmitted to the link 152. Then, the link 152 rotates counterclockwise, that is, in the rising direction, about the support shaft A1 forming the connection portion with the base 131.

[0060] (a) Linkage mechanism In this embodiment, only one of the two links 152 (152L, 152R) and 153 (153L, 153R), i.e., link 152, is driven by the drive unit 201. Therefore, in order for links 152 and 153 to form a parallel link mechanism 154 together with the support unit 111 and the base unit 131, the rotational movement of link 152 driven by the drive unit 201 must be transmitted to link 153 as well. The interlocking mechanism 171 is for realizing this.

[0061] As shown in FIGS. 3 and 5(A), the interlocking mechanism 171 shares the bar 162 fixedly spanned between the pair of left and right links 152L and 152R located on the foot side FS as the motion conversion unit 161. Separately from this bar 162, a bar 172 is also fixedly spanned between the pair of left and right links 153L and 153R located on the head side HS, and these two bars 162 and 172 are interlocked. As a mechanism for this, the bed lifting device 101 includes a pair of left and right interlocking pieces 173 and 174 provided on the two bars 162 and 172 respectively, and a pair of left and right interlocking links 175 spanned between these interlocking pieces 173 and 174 respectively.

[0062] The bar 172 is, like the bar 162, for example, a pipe-shaped member made of metal, and is fixed to the inner wall portions of the pair of links 153L and 153R by welding. The interlocking pieces 173 and 174 are, for example, flat plate-shaped members made of metal, and are fixed to the bars 162 and 172 by welding respectively. The interlocking link 175 is also, for example, a flat plate-shaped member made of metal.

[0063] The bar 172 has the same shape and size as the bar 162, and is fixed at a position closer to the connecting portion with the base unit 131 than the connecting portion with the support unit 111 in the pair of links 153L and 153R, similar to the fixing position of the bar 162 with respect to the pair of links 152L and 152R. The fixing position of the bar 162 with respect to the pair of links 152L and 152R and the fixing position of the bar 172 with respect to the pair of links 153L and 153R are at the same position.

[0064] The pair of interlocking pieces 173 and 174 have the same shape and size as the driving piece 163, and are fixedly provided on the bars 162 and 172 at the same angle as the driving piece 163.

[0065] In the present embodiment, the one fixed to the bar 162 is called the interlocking piece 173, and the one fixed to the bar 172 is called the interlocking piece 174. When the bed lifting device 101 is viewed in plan with the head side HS facing up, the one located on the left side is called the interlocking pieces 173L and 174L, and the one located on the right side is called the interlocking pieces 173R and 174R. The left interlocking pieces 173L and 174L arranged in the same virtual plane along the X direction and the right interlocking pieces 173R and 174R arranged in the same virtual plane along the X direction are arranged symmetrically about the central positions of the two bars 162 and 172.

[0066] The interlocking link 175 is spanned across the tip portions of the two interlocking pieces 173 and 174. At this time, the interlocking link 175 is rotatably attached to one interlocking piece 173 by a support shaft A4, and is rotatably attached to the other interlocking piece 174 by a support shaft A5. Since the two support shafts A4 and A5 both extend along the Y axis, the two interlocking pieces 173 and 174 and the interlocking link 175 are rotatable about the Y axis.

[0067] In the present embodiment, when the bed lifting device 101 is viewed in plan with the head side HS facing up, the one located on the left side is called the interlocking link 175L, and the one located on the right side is called the interlocking link 175R.

[0068] (e) Connection between the bed and the bed lifting device As shown in FIGS. 7 and 8, the bed frame 31 of the bed 11 is a structure in which both ends of a pair of side rails 33 are connected by end frames 34 to form a rectangular frame shape. A reinforcing column 35 is spanned at the central position in the X direction between the pair of side rails 33, and reinforcing plates 36 are spanned at four locations. A leg portion 32 located at the central portion is fixed to the reinforcing column 35, and four leg portions 32 located at the four corners are fixed to the reinforcing plates 36.

[0069] On the inner circumferential sides of the pair of side rails 33 and the pair of end frames 34, a rail plate 37 for supporting a bamboo mat (not shown) is fixed. The bamboo mat is respectively fitted into the head side HS and the foot side FS with the reinforcing columns 35 in between and is supported by the rail plate 37.

[0070] For convenience of explanation, in FIG. 7, the second reinforcing plate 36 from the left is referred to as the reinforcing plate 36a, and the second reinforcing plate 36 from the right is referred to as the reinforcing plate 36b. The bed lifting device 101 is fixed to the reinforcing plate 36a and the reinforcing plate 36b respectively. More specifically, as described above, the pair of connecting members 113 constituting the support portion 111 are provided with bolt holes 113a at both ends (see FIG. 3). The connecting member 113 on the foot side FS is bolted to the reinforcing plate 36a by a bolt (not shown) passed through the bolt hole 113a. The connecting member 113 on the head side HS is bolted to the reinforcing plate 36b by a bolt (not shown) passed through the bolt hole 113a.

[0071] In this way, the support portion 111 is fixed to the bed frame 31 and attached to the lower part of the bed 11.

[0072] The attachment state and attachment position of the bed lifting device 101 to the bed frame 31 depend on the form of the bed frame 31. In other words, as one way of thinking, the overall shape of the bed lifting device 101 and the position of the bolt hole 113a provided in the connecting member 113 are adapted to the shape and dimensions of the bed frame 31 intended for attaching the bed lifting device 101. As another way of thinking, the bed frame 31 is configured according to the overall shape of the bed lifting device 101 and the position of the bolt hole 113a provided in the connecting member 113.

[0073] Whichever design concept is adopted, the bed frame 31 and the bed lifting device 101 must be combined while maintaining the strength for the bed lifting device 101 to lift the bed 11 without interference between the movable region generated by the drive of the drive unit 201 and the bed frame 31.

[0074] Figures 9 and 10 show another example of the bed frame 31. Regarding the basic structure, it is common with the bed frame 31 illustrated in FIGS. 7 and 8, and the attachment structure of the bed lifting device 101 to the bed frame 31 is also common, so the description is omitted. However, FIG. 10 is a bottom view with respect to the plan view of FIG. 8, and a portion that is aligned with the connecting portion with the bed lifting device 101, that is, the bolt hole 113a (see FIG. 3) provided in the connecting member 113, appears. In FIG. 10, this portion is schematically indicated by a black circle marked with the symbol AT.

[0075] (c) Foot switch The bed lifting device 101 is provided with a foot switch 211 as a switch.

[0076] As shown in FIG. 11, the foot switch 211 has the upper surface of the housing as the operation surface 212, and an upward instruction portion 213 for instructing the upward movement of the bed 11 and a downward instruction portion 214 for instructing the downward movement of the bed 11 are provided on the operation surface 212. The upward instruction portion 213 and the downward instruction portion 214 are operation buttons that can be operated by stepping on them with the foot. A display portion 215 composed of the characters "UP" corresponding to the upward instruction portion 213 and the characters "DOWN" corresponding to the downward instruction portion 214 is attached to the operation surface 212.

[0077] When the upward instruction portion 213 is operated and input, the foot switch 211 outputs an upward instruction signal toward a control portion 231 described later. When the downward instruction portion 214 is operated and input, the foot switch 211 outputs a downward instruction signal toward the control portion 231.

[0078] (e) Control portion The drive unit 201 incorporates a control unit 231. The control unit 231 controls the drive unit 201 such that the facing interval OD is alternatively switched between a first interval OD1 and a second interval OD2. The alternative switching of the facing interval OD is executed by controlling the drive unit 201 to raise the base 131 when the raising instruction unit 213 is operated, and to lower the base 131 when the lowering instruction unit 214 is operated.

[0079] As shown in FIG. 12, the core of the control unit 231 is a control circuit 232. The control circuit 232 is constituted by a microcomputer that interprets and executes a program P for driving and controlling the bed lifting device 101, mainly with a CPU 233 that centrally controls each part. The CPU 233 stores the OS and the program P in the flash memory 234, and executes processing according to the program P while using the main memory 235 as a work area. The main memory 235 is used as a counter, for example.

[0080] As another example, the control circuit 232 may be constituted by an integrated circuit or the like that sequentially executes prescribed processing.

[0081] A motor drive circuit 236 and a signal input circuit 237 are connected to the control circuit 232. The motor drive circuit 236 is a circuit that receives a command from the control circuit 232 and controls the operation of a motor M incorporated in the drive unit 201. The signal input circuit 237 is a circuit that digitizes a signal output from the foot switch 211 and transmits it to the control circuit 232.

[0082] (3) Function As shown in FIG. 13, the CPU 233 of the control circuit 232 waits for a determination as to whether a raising instruction signal indicating that the raising instruction unit 213 has been operated is received (step S101). If the reception determination is not made (NO in step S101), it waits for a determination as to whether a lowering instruction signal indicating that the lowering instruction unit 214 has been operated is received (step S102).

[0083] (A) Process of lifting the bed from the floor When the CPU 233 determines that it has received the lifting instruction signal (YES in step S101), it performs a counter check (step S103) and determines whether it can drive the drive unit 201 to lift the bed 11 (step S104).

[0084] In the bed lifting device 101, when the opposing interval OD between the support portion 111 and the base portion 131 is at the maximum second interval OD2max, the bed 11 is in a state of being lifted to the maximum, and the second interval OD2 cannot be increased further. In this case, the CPU 233 determines that it cannot drive the drive unit 201 (NO in step S104).

[0085] The control circuit 232 manages the opposing interval OD between the support portion 111 and the base portion 131 by a counter (not shown). As an example, the counter is set in a part of the area of the flash memory 234 according to a program P for driving and controlling the bed lifting device 101, and counts the driving status of the motor M built in the drive unit 201. The driving status of the motor M is, as an example, the driving time, and as another example, the number of driving pulses. Of course, as long as it is an element that can monitor the driving status of the motor M, not limited to the driving time and the number of driving pulses, any element can be used.

[0086] In the counter check in step S103, the opposing interval OD is estimated by referring to the count value recorded in the counter. In the present embodiment, the count value is indicated by C (see steps S106, 107, 113, 114). The program P sets the count value C to 0 when the opposing interval OD between the support portion 111 and the base portion 131 is the first interval OD1, and sets the count value C to N when it is the maximum second interval OD2max.

[0087] When the CPU 233 determines that it can drive the drive unit 201 as a result of the counter check in step S103 (YES in step S104), it outputs a drive signal for driving the rotation shaft of the motor M in the forward rotation direction to the motor drive circuit 236 (step S105). The motor drive circuit 236 that receives this drive signal rotates the rotation shaft of the motor M in the forward direction.

[0088] When the rotation shaft of the motor M rotates in the forward direction, a rotational force is transmitted to the rod 202 via the coupling 203, and the rod 202 moves in the forward direction, that is, the protruding direction. Then, as shown in FIGS. 2(A) and 2(B), a counterclockwise rotational force is transmitted to the links 152 (152L, 152R) via the drive piece 163 and the bar 162 (see FIG. 3). As a result, the links 152 (152L, 152R) rotate counterclockwise, that is, in the rising direction, about the support shaft A1.

[0089] At this time, in the interlocking mechanism 171, the interlocking piece 173 behaves in the same manner as the drive piece 163. Since the interlocking piece 173 is connected to the interlocking piece 174 via the interlocking link 175, the interlocking piece 174 also behaves in the same manner as the drive piece 163 and the interlocking piece 173. As a result, in synchronization with the rotation of the links 152 (152L, 152R), the links 153 (153L, 153R) also rotate counterclockwise, that is, in the rising direction, about the support shaft A1.

[0090] In this way, the parallel link mechanism 154 formed by the support portion 111, the base portion 131, and the pair of left and right links 152 (152L, 152R), 153 (153L, 153R) functions, and the support portion 111 and the base portion 131 expand the opposing interval OD. Then, the opposing interval OD transitions from the first interval OD1 (see FIG. 2(A)) to the second interval OD2 (see FIG. 2(B)).

[0091] FIG. 14(A) is a side view of the bed 11 and the bed lifting device 101 when the bed 11 is in use. In the flowchart of FIG. 13, before driving the motor M in the forward rotation in step S105, the opposing interval OD between the support portion 111 and the base portion 131 is the first interval OD1 (see FIG. 2(A)). At this time, the base portion 131 of the bed lifting device 101 maintains a state with a gap G from the floor F.

[0092] As shown in FIG. 14(B), when the motor M is driven in the forward rotation in this state (step S105), the base portion 131 moves away from the support portion 111 and the base portion 131 hits the floor F.

[0093] As shown in FIG. 14(C), when the forward rotation drive of the motor M continues and the opposing interval OD further expands, the support portion 111 is supported by the base portion 131 grounded on the floor F and the support portion 111 rises to lift the bed 11. The lifting of the bed 11 continues until the opposing interval OD reaches the second interval (see FIG. 2(B)).

[0094] When the opposing interval OD between the support portion 111 and the base portion 131 reaches the maximum second interval OD2max, the bed 11 is in the state of being lifted to the maximum extent. At this time, the control circuit 232 must stop the forward rotation drive of the motor M. So to speak, the function of a limiter is required. This function is realized by the following processing in the control circuit 232.

[0095] When the CPU 233 starts the forward rotation drive of the motor M (step S105), the CPU 233 increments the count value C of the counter (step S106) and determines whether the count value C has reached N, that is, the value when the opposing interval OD reaches the maximum second interval OD2max (step S107).

[0096] The CPU 233 continues to increment the count value C until it determines that the count value C has reached N (step S106). When it determines that the count value C has reached N (YES in step S107), the CPU 233 outputs a hold signal to the motor drive circuit 236 (step S108).

[0097] Upon receiving the hold signal, the motor drive circuit 236 holds the motor M and fixes the rotating shaft so that it does not rotate freely. As a result, the position of the rod 202 is also fixed, and the bed 11 is maintained in a state of being lifted from the floor F (see Fig. 14(C)).

[0098] At this time, the opposing interval OD between the support portion 111 and the base portion 131 is maintained at the maximum second interval OD2max, and the bed 11 is lifted to the maximum extent.

[0099] When the CPU 233 receives the lowering instruction signal, it stops outputting the hold signal to the motor drive circuit 236 and repeats the processing of the flowchart shown in Fig. 13. The stop of the output of the hold signal is executed by a subroutine (not shown).

[0100] (a) Process of lowering the bed to the floor When the CPU 233 determines that it has received the lowering instruction signal (YES in step S102), it performs a counter check (step S110) and determines whether it can drive the drive unit 201 to lower the bed 11 (step S111).

[0101] In the bed lifting device 101, when the opposing interval OD between the support portion 111 and the base portion 131 has reached the first interval OD1, it is not possible to further reduce the opposing interval OD. In this case, the CPU 233 determines that it cannot drive the drive unit 201 (NO in step S111). If the CPU 233 determines, as a result of the counter check in step S110, that it can drive the drive unit 201 (YES in step S111), it outputs a drive signal for driving the rotating shaft of the motor M in the reverse direction to the motor drive circuit 236 (step S112). Upon receiving this drive signal, the motor drive circuit 236 rotates the rotating shaft of the motor M in the reverse direction.

[0102] When the rotating shaft of the motor M rotates in the reverse direction, a rotational force is transmitted to the rod 202 via the coupling 203, and the rod 202 moves in the retracting direction, that is, the direction in which it is pulled in. Then, in FIGS. 2(A) and 2(B), a clockwise rotational force is transmitted to the links 152 (152L, 152R) via the drive piece 163 and the bar 162. As a result, the links 152 (152L, 152R) rotate clockwise, that is, in the folding direction, about the support shaft A1.

[0103] At this time, in the interlocking mechanism 171, the interlocking piece 173 behaves in the same manner as the drive piece 163. Since the interlocking piece 173 is connected to the interlocking piece 174 via the interlocking link 175, the interlocking piece 174 also behaves in the same manner as the drive piece 163 and the interlocking piece 173. As a result, in synchronization with the rotation of the link 152 (152L, 152R), the link 153 (153L, 153R) also rotates clockwise, that is, in the folding direction, about the support shaft A1.

[0104] In this way, the parallel link mechanism 154 formed by the support portion 111, the base portion 131, and the pair of left and right links 152 (152L, 152R), 153 (153L, 153R) functions, and the support portion 111 and the base portion 131 reduce the opposing interval OD. Then, the opposing interval OD transitions from the second interval OD2 (see FIG. 2(B)) to the first interval OD1 (see FIG. 2(A)).

[0105] FIG. 14(C) is a side view of the bed 11 and the bed lifting device 101 after the bed 11 has been lifted. Here, it is assumed that in the flowchart of FIG. 13, at the stage before the motor M is driven to rotate in the reverse direction in step S112, the opposing interval OD between the support portion 111 and the base portion 131 is the second interval OD2 (see FIG. 2(B)). At this time, the base portion 131 of the bed lifting device 101 is in contact with the floor F, and the support portion 111 supports the bed 11 lifted from the floor F.

[0106] As shown in FIG. 14(B), when the motor M is driven to rotate in the reverse direction in this state (step S112), the opposing interval OD becomes smaller, and accordingly, the bed 11 descends and is installed on the floor F.

[0107] As shown in Fig. 14(A), when the reverse rotation drive of the motor M continues, the opposing interval OD further decreases and returns to the first interval OD1. As a result, a gap G is generated between the base 131 of the bed lifting device 101 and the floor F.

[0108] When the opposing interval OD between the support portion 111 and the base portion 131 becomes the first interval OD1, the bed lifting device 101 is in the maximally folded state. At this time, the control circuit 232 must stop the reverse rotation drive of the motor M. So to speak, the function of a limiter is required. This function is realized by the following processing in the control circuit 232.

[0109] When the CPU 233 starts the reverse rotation drive of the motor M (step S112), it decrements the count value C of the counter (step S113) and determines whether the count value C has reached 0, that is, the value when the opposing interval OD is the first interval OD1 (step S114).

[0110] The CPU 233 continues to decrement the count value C until it determines that the count value C has reached 0 (step S113). When it determines that the count value C has reached 0 (YES in step S114), it stops the output of the drive signal to the motor drive circuit 236 (step S115).

[0111] The motor drive circuit 236, from which the drive signal from the control circuit 232 is cut off, stops the drive of the motor M. At this time, the bed 11 is installed on the floor F, and a gap G is generated between the base 131 of the bed lifting device 101 and the floor F.

[0112] (c) Continuous operation of the rising support portion and the falling support portion In this embodiment, while the raising instruction unit 213 is being operated, the control unit 231 controls the drive unit 201 to increase the facing interval OD until it reaches the maximum second interval OD2max, and raise the bed 11. Also, while the lowering instruction unit 214 is being operated, the control unit 231 controls the drive unit 201 to decrease the facing interval OD until it reaches the first interval OD1, and lower the bed 11.

[0113] The CPU 233 executes the processes of steps S109 and 116 in order to realize drive control of the motor M in response to continuous operations of the raising instruction unit 213 and the lowering instruction unit 214.

[0114] (Step S109) When executing the process of raising the bed 11 (steps S101, S103 to 108 in FIG. 13), the CPU 233 determines whether or not a raising instruction signal is received until it determines that the count value C has reached N (YES in step S107) (step S109). This process is to confirm whether or not the raising instruction unit 213 is continuously operated.

[0115] When the raising instruction unit 213 is continuously operated, a raising instruction signal is continuously input to the signal input circuit 237. At this time, the CPU 233 determines the reception of the raising instruction signal (YES in step S109), and repeats the processes of steps S106 to 107 and 109.

[0116] When the operation input of the raising instruction unit 213 is stopped halfway, the raising instruction signal is no longer input to the signal input circuit 237. Then, the CPU 233 stops determining the reception of the raising instruction signal (NO in step S109). Even if it has not been determined that the count value C has reached N (NO in step S107), if the CPU 233 stops determining the reception of the raising instruction signal (NO in step S109), it outputs a hold signal to the motor drive circuit 236 (step S108).

[0117] Upon receiving the hold signal, the motor drive circuit 236 holds the motor M and fixes the rotating shaft so that it does not rotate freely. As a result, the position of the rod 202 is also fixed.

[0118] At this time, the facing interval OD between the support portion 111 and the base portion 131 is determined as the facing interval OD when the foot is removed from the raising instruction portion 213 when the operation input to the raising instruction portion 213 is stopped, for example, when the raising instruction portion 213 is operated by stepping on it with the foot. The same applies to the position of the bed 11 in the Z direction. The bed 11 may not be separated from the floor F, or even if it was separated from the floor F, it is not at the maximum lifted position.

[0119] When the CPU 233 receives the raising instruction signal or the lowering instruction signal, it stops the output of the hold signal to the motor drive circuit 236 and repeats the processing of the flowchart shown in FIG. 13. The stop of the output of the hold signal is executed by a subroutine (not shown).

[0120] (Step S116) When executing the process of lowering the bed 11 (steps S102, S110 to S115 in FIG. 13), the CPU 233 determines whether or not a lowering instruction signal is received until it determines that the count value C has reached 0 (YES in step S114) (step S116). This process is to confirm whether the lowering instruction portion 214 continues to be operated.

[0121] When the lowering instruction portion 214 continues to be operated, the lowering instruction signal continues to be input to the signal input circuit 237. At this time, the CPU 233 determines the reception of the lowering instruction signal (YES in step S116) and repeats the processing of steps S113 to S114 and 116.

[0122] If the operation input of the lowering instruction unit 214 is stopped halfway, the lowering instruction signal is no longer input to the signal input circuit 237. Then, the CPU 233 stops determining the reception of the lowering instruction signal (NO in step S116). Even before determining that the count value C has reached 0 (NO in step S114), if the CPU 233 stops determining the reception of the lowering instruction signal (NO in step S116), it outputs a hold signal to the motor drive circuit 236 (step S108).

[0123] The motor drive circuit 236 that has received the hold signal holds the motor M and fixes the rotating shaft so that it does not rotate freely. As a result, the position of the rod 202 is also fixed.

[0124] At this time, the opposing interval OD between the support portion 111 and the base portion 131 is determined as the opposing interval OD when the foot is removed from the lowering instruction unit 214 when the operation input of the lowering instruction unit 214 is stopped, for example, when the lowering instruction unit 214 is operated by stepping on it with the foot. The same applies to the position of the bed 11 in the Z direction. The bed 11 may or may not be separated from the floor F.

[0125] When the CPU 233 receives the raising instruction signal or the lowering instruction signal, it stops outputting the hold signal to the motor drive circuit 236 and repeats the processing of the flowchart shown in FIG. 13. The stop of the output of the hold signal is executed by a subroutine (not shown).

[0126] (4) Operational effects (A) Basic operational effects The bed lifting device 101 of the present embodiment is attached to the lower part of the bed 11 and is stored in a folded state (see FIGS. 1, 2(A), and 14(A)) in the space S between the floor F and the bed 11. If the raising instruction unit 213 of the foot switch 211 is stepped on from this state, the bed lifting device 101 is started up, and the base portion 131 grounded to the floor F serves as a support, and the bed 11 can be lifted.

[0127] If the bed 11 is lifted from the bed frame F, the bed-making operation becomes easier, and the physical burden on the operator can be reduced.

[0128] (a) Gap with the floor When the bed lifting device 101 is installed on the floor F and is interposed between the floor F and the bed 11, the impact from the mattress 51 in use is transmitted to the bed lifting device 101.

[0129] On the other hand, the bed lifting device 101 of the present embodiment is attached to the lower part of the bed 11 and maintains a state in which a gap G is provided between it and the floor F. Therefore, it is possible to prevent a failure of the lifting mechanism 151 caused by the transmission of the impact from the mattress 51 in use.

[0130] In addition, since a gap G is formed between the floor F and the bed lifting device 101, for example, if casters are attached to the bed 11, it becomes easy to move the bed 11 with a light force.

[0131] The gap G between the floor F and the bed lifting device 101 also contributes to preventing rattling of the bed lifting device 101 caused by, for example, the transmission of vibrations from the mattress 51.

[0132] The structure of the bed lifting device 101 that secures the gap G with the floor F also brings benefits in relation to the levelness of the floor F. This will be described in detail.

[0133] The floor F on which the bed 11 is installed is not necessarily a perfect horizontal plane, and it is often somewhat distorted or has unevenness. Therefore, when the bed 11 is installed on the floor F, the distortion and unevenness of the floor F are absorbed by the deflection of the bed frame 31 or the deformation of the floor F itself. If it cannot be completely absorbed, rattling will occur in the bed 11. The rattling of the bed 11 not only causes discomfort to the user itself but also impairs the levelness of the bed 11.

[0134] When considering the levelness of such a floor F, for example, as described in Patent Documents 1 to 3, if the lifting device of the bed 11 is installed on the floor F, not only the legs 32 of the bed 11 but also the lifting device is grounded to the floor F, and the number of parts grounded to the floor F increases accordingly. If the number of grounded parts to the floor F increases, the number of locations that pick up distortion and unevenness increases, so for example, the following problems are caused.

[0135] First, the burden on the bed frame 31 that bends in an attempt to absorb the distortion and unevenness of the floor F and on the bed lifting device 101 to which an external force exceeding the play of each part is applied increases.

[0136] Second, the chance of rattling of the bed 11 that occurs when the distortion and unevenness of the floor F cannot be completely absorbed increases.

[0137] Third, a large load is applied to the fixed part between the bed frame 31 and the bed lifting device 101, and the structural strength of this part must be ensured.

[0138] The bed lifting device 101 of the present embodiment secures a gap G from the floor F, so such problems can be solved.

[0139] (c) Stability Each part constituting the bed lifting device 101 has many mechanical elements, such as the support part 111, the base part 131, a pair of links 152 (152L, 152R), 153 (153L, 153R), the components of the motion conversion part 161, and the components of the interlocking mechanism 171, which are symmetric about the left and right. Therefore, the left - right balance is achieved, and good stability can be obtained even when the bed 11 is lifted.

[0140] Also, the fact that the support part 111, the base part 131, and a pair of links 152 (152L, 152R), 153 (153L, 153R) form a parallel link mechanism 154 also contributes to the improvement of stability.

[0141] (d) Bed height setting In this embodiment, while stepping on the raising instruction part 213 or the lowering instruction part 214 of the foot switch 211, the facing interval OD between the support part 111 and the base part 131 can be varied, and the lifting height of the bed 11 can be set as appropriate. Therefore, it is easy to set the height of the bed 11 according to the height and body shape of individual workers, or to set the height of the bed 11 according to operations such as bed making or cleaning under the bed 11.

[0142] Also, if the raising instruction part 213 or the lowering instruction part 214 is stepped on, the bed 11 can be raised or lowered, and when the foot is released, the height of the bed 11 can be determined at that position. Therefore, the height of the bed 11 can be set intuitively, and the operability is good.

[0143] 3. Modification In practice, various modifications and changes are allowed.

[0144] For example, the support part 111 does not necessarily have to be configured as the frame body 114. The same applies to the base part 131.

[0145] The drive part 201 may be of a type that imparts a rotational motion to the lifting mechanism 151 regardless of the linear actuator. Alternatively, a hydraulic actuator may be used as the drive part 201.

[0146] In this embodiment, an example in which five legs 32 supporting the bed frame 31 are provided is shown. The number of legs 32 does not necessarily have to be five, and may be as few as four, or may be six to nine or more, which is more than five.

[0147] Regarding the length of each leg 32, it depends on the length from the attachment part of each leg 32 at the lower part of the bed frame 31 to the floor F, that is, the height of the space S. For each leg 32, when the height of the space S varies, the length of each leg 32 can also be determined according to the height of the space S at the attachment part.

[0148] In this embodiment, the flowchart of FIG. 13 is shown as the process for driving and controlling the bed lifting device 101, but this is merely an example. The bed lifting device 101 can be driven and controlled by various other processes.

[0149] All other manner of modifications and alterations are permitted.

Explanation of Reference Numerals

[0150] 11 Bed 31 Bed Frame 32 Legs 33 Side Rails 34 End Frame 35 Reinforcing Pillars 36, 36a, 36b Reinforcing Plates 37 Rail Plate 51 Mattress 101 Bed Lifting Device 111 Support Portion 112 Side Member 113 Connecting Member 113a Bolt Hole 114 Frame 131 Base 132 Side Member 133 Connecting Member 134 Frame 135 Reinforcing Member 136 Support Piece 151 Lifting Mechanism 152, 152L, 152R Links 153, 153L, 153R Links 154 Parallel Link Mechanism 161 Motion Conversion Portion 162 Bar 163 Driving Piece 171 Interlocking Mechanism 172 Bar 173, 173L, 173R Interlocking Pieces 174, 174L, 174R Interlocking Pieces 175, 175L, 175R Interlocking Links 201 Drive unit (linear actuator) 202 Rod 203 Coupling 211 Foot switch 212 Operation surface 213 Rising indicator 214 Lowering indicator 215 Display unit 231 Control unit 232 Control circuit 233 CPU 234 Flash memory 235 Main memory 236 Motor drive circuit 237 Signal input circuit A1 - A5 Support shafts Position matching the AT bolt hole E Buffer feet F Floor FS Foot side HS Head side G Gap OD Opposite interval OD1 First interval OD2 Second interval OD2max Maximum second interval P Program S Space W Wall

Claims

1. A support part attached to the bottom of the bed to support the bed; A base that can be placed on a floor; a lifting mechanism that connects the support portion and the base portion so that a distance between the support portion and the base portion can be varied; a drive unit that applies a drive force to the lifting mechanism to vary the opposing distance; A control unit that controls the drive unit; Equipped with The lifting mechanism varies the opposing distance between a first distance at which the base does not contact a floor and a second distance at which the bed is lifted up from the floor, the control unit controls the drive unit so that the opposing distance is switched alternatively between the first distance and the second distance. Bed lifting device.

2. The lifting mechanism is provided on the head side and the foot side of the bed, respectively, and has a pair of left and right links that connect the support part and the base part rotatably around an axis extending in the left-right direction of the bed.

2. The bed lifting device according to claim 1.

3. The pair of left and right links provided on the head side and foot side of the bed respectively form a parallel link mechanism together with the support part and the base part.

3. A bed lifting device according to claim 2.

4. At least one of the support portion and the base portion is a frame body having a rectangular shape.

4. A bed lifting device according to claim 1.

5. The driving unit is a linear actuator that causes a rod to move linearly, The lifting mechanism has a motion conversion unit that converts the linear motion of the rod into a rotational motion of the pair of left and right links. A bed lifting device according to claim 2 or 3.

6. The motion conversion unit includes: a bar fixedly hung between the pair of left and right links at a position closer to a connection portion with the base than to a connection portion with the support part; a driving piece fixedly provided on the bar so as to protrude toward the support portion; It has The linear actuator comprises: a base mounted to the base for rotation about the axis; The tip end of the rod is connected to the tip end of the driving piece so as to be rotatable around the axis.

6. A bed lifting device according to claim 5.

7. The driving piece is provided at a central position of the bar.

7. A bed lifting device according to claim 6.

8. The lifting mechanism includes: the linear actuator and the motion converter are provided on only one of the pair of left and right links, the link being located on the head side or the link being located on the foot side; a linking mechanism for linking the pair of left and right links arranged on the head side with the pair of left and right links arranged on the foot side, 6. A bed lifting device according to claim 5.

9. The lifting mechanism includes: the linear actuator and the motion converter are provided on only one of the pair of left and right links, the link being located on the head side or the link being located on the foot side; a linking mechanism for linking the pair of left and right links arranged on the head side with the pair of left and right links arranged on the foot side, 7. A bed lifting device according to claim 6.

10. The interlocking mechanism includes: the bar is stretched between each of the pair of left and right links arranged on the head side and the foot side, respectively; Two interlocking pieces fixedly provided on the two bars so as to protrude toward the support portion; an interlocking link that is stretched between the two interlocking pieces so as to be rotatable around the axis; It has 10. A bed lifting device according to claim 9.

11. The two interlocking pieces and the interlocking link are provided in pairs on the left and right sides of the bar, A bed lifting device according to claim 10.

12. The driving piece is provided at a central position of the bar. A bed lifting device according to claim 11.

13. A switch having a rise instruction part for instructing the bed to rise and a fall instruction part for instructing the bed to fall is provided, The control unit controls the drive unit to raise the bed when the lift instruction unit is operated, and controls the drive unit to lower the bed when the lowering instruction unit is operated.

4. A bed lifting device according to claim 1.

14. The switch is a foot switch for operating the ascent instruction unit and the descent instruction unit with a foot.

14. A bed lifting device according to claim 13.

15. The control unit is while the lift-up instruction unit is being operated, the drive unit is controlled to increase the opposing distance until the opposing distance becomes the maximum second distance; while the lowering instruction unit is operated, the driving unit is controlled so as to decrease the opposing distance until the opposing distance becomes the first distance.

15. A bed lifting device according to claim 14.

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