Lifting device

Abstract

To provide an elevating device capable of suppressing deterioration in safety and appearance.SOLUTION: A support side lower shaft member 31 and a support side upper shaft member 32 arranged in parallel are fixed to the support 3, and a receiving seat side lower shaft member 51 and a receiving seat side upper shaft member 52 arranged in parallel are fixed to the receiving seat 5; The arm body 40 is rotatably connected to both of the support side lower shaft member 31 and the support side upper shaft member 32 at one end, and rotatably connected to both of the receiving seat side lower shaft member 51 and the receiving seat side upper shaft member 52 at the other end, and the support side lower shaft member 31 and the support side upper shaft member 32 and the receiving seat side lower shaft member 51 and the receiving seat side upper shaft member 52 constitute a parallel link mechanism X, and the arm body 40 stores an expansion device 41 capable of restraining the operation of the parallel link mechanism X.SELECTED DRAWING: FIG. 10A

Description

[Technical Field]

[0001] The present invention relates to an elevating device in which an object supported by an arm having a four-bar link mechanism can be freely raised and lowered. [Background technology]

[0002] Conventionally, there has been disclosed a lifting device in which an object supported by an arm having a four-bar link mechanism, particularly a parallel link mechanism, can be freely raised and lowered. Such a lifting device is applied in a variety of fields.

[0003] Patent Document 1 discloses a lift device for trucks as an elevator. In this lift device for trucks, a parallel link 5 is connected between a main frame 4 mounted laterally on a chassis frame 2 and a table 3. The parallel link 5 is composed of a pair of left and right hollow rectangular cylindrical upper frames 6 and a pair of left and right lifting cylinders 7 that raise the table 3. In addition, a lifting cylinder 40 that raises and lowers the table 3 is journaled on a pin 41 journaled on a receiving plate 10 of the main frame 4.

[0004] Patent Document 2 discloses a desk that functions as an elevator. The desk includes a tabletop support 6 that supports a tabletop 20. The tabletop support 6 includes a pair of left and right parallel link mechanisms 9 that are mounted so as to be rotatable in the vertical direction. The parallel link mechanisms 9 include a pair of left and right first link arms 12, a second link arm 15 that is staggered and positioned higher than the first link arms 12, and an elevator 18 that is substantially T-shaped in side view and is connected to the front ends of the first and second link arms 12, 15 by shafts 16, 17 that face left and right so that the first and second link arms 12, 15 are parallel to each other. The tabletop 20 is raised and lowered by rotating the first link arm 12 in the vertical direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-121632 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-44108 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the parallel link 5 described in Patent Document 1 and the parallel link mechanism 9 described in Patent Document 2 are exposed. Therefore, there is a risk of fingers getting pinched between the upper frame 6 and the elevation cylinder 7 that constitute the parallel link 5, or between the first link arm 12 and the second link arm 15 that constitute the parallel link mechanism X9. Furthermore, the exposure of the parallel link 5 and the parallel link mechanism 9 may give the user an impression of cumbersomeness.

[0007] The present invention has been made to solve such problems, and has an object to provide an elevator device that can prevent a decrease in safety and aesthetic appearance. [Means for solving the problem]

[0008] In order to achieve the above object, an elevator device according to one aspect of the present invention has the following features.

[0009] (1) An arm including an arm body having a hollow structure over the entire length in the axial direction and a closed cross-sectional structure that is closed in the circumferential direction; a support body that supports the arm; a support object that is an object to be supported by the arm; and a seat that receives the support object and is supported by the arm; A support-side lower shaft member and a support-side upper shaft member arranged in parallel are fixed to the support body, A catch-side lower shaft member and a catch-side upper shaft member arranged in parallel are fixed to the catch, the arm body is rotatably connected at one end to both the support-side lower shaft member and the support-side upper shaft member, and at the other end to both the catch-side lower shaft member and the catch-side upper shaft member, the support-side lower shaft member, the support-side upper shaft member, the catch-side lower shaft member, and the catch-side upper shaft member constitute a four-bar link mechanism, The four-bar link mechanism is actuated to lift and lower the supported object, The arm body is characterized in that an extension device is stored inside the arm body, which can extend and retract in response to the operation of the four-bar link mechanism and can restrict the operation of the four-bar link mechanism. According to the aspect described in (1) above, the arm body constituting part of the four-bar link mechanism itself has a closed cross-sectional structure that is closed in the circumferential direction, and an extension device that can restrict the operation of the four-bar link mechanism is stored inside the arm body. Therefore, fingers or the like will not be pinched in the arm when the four-bar link mechanism operates. In addition, the appearance of the arm will not be complicated. Therefore, deterioration in safety and aesthetics can be suppressed. In addition, "capable of restricting the operation of the four-bar linkage" in relation to the telescopic device includes both completely restricting the operation of the four-bar linkage and allowing some so-called "play" in the operation of the four-bar linkage, but substantially (mostly) restricting said operation. Also, "the telescopic device is stored" includes both the entire telescopic device being stored and part of the telescopic device being stored.

[0010] (2) In the lifting device described in (1), the support-side lower shaft member and the support-side upper shaft member are parallel to the catch-side lower shaft member and the catch-side upper shaft member, and the center-to-center distance between the support-side lower shaft member and the support-side upper shaft member is the same as the center-to-center distance between the catch-side lower shaft member and the catch-side upper shaft member, The support-side lower shaft member, the support-side upper shaft member, the catch-side lower shaft member, and the catch-side upper shaft member may form a parallel link mechanism. According to the aspect described in (2) above, the posture of the supported object remains constant while the supported object is raised or lowered. Therefore, for example, if the supported object is a tabletop, the tabletop can be maintained horizontally regardless of the height at which the tabletop is fixed. (3) In the lifting device described in (1), The extension device may be rotatably connected to both the support-side lower shaft member and the catch-side upper shaft member, or to both the support-side upper shaft member and the catch-side lower shaft member. By connecting the extension device to both the support-side lower shaft member and the catch-side upper shaft member, or to the support-side upper shaft member and the catch-side lower shaft member, which constitute the four-bar link mechanism, the link mechanism can be reliably restrained. (4) In the lifting device described in (1), The arm body has a lower arm member disposed relatively lower and having a U-shaped cross section, and an upper arm member disposed relatively upper and also having a U-shaped cross section, The lower arm member and the upper arm member may be arranged symmetrically in a direction perpendicular to the axial direction, and the cross-sectional shape of the hollow structure of the arm body perpendicular to the axial direction may be approximately rectangular. The aspect described in (4) above makes it easier to manufacture the lifting device, particularly the arm, and therefore reduces the manufacturing time. [Effects of the Invention]

[0011] According to the present invention, it is possible to prevent a decrease in safety and aesthetic appearance of the lifting device. [Brief explanation of the drawings]

[0012] [Figure 1A] FIG. 2 is a perspective view of the cart in the highest position. [Figure 1B] FIG. 2 is a perspective view of the cart in the highest position. [Figure 2A] FIG. 10 is a front view of the cart in the highest position. [Figure 2B] FIG. 10 is a rear view of the cart in the highest position. [Figure 2C] FIG. 10 is a plan view of the cart in the highest position. [Figure 2D] FIG. 10 is a bottom view of the cart in the highest position. [Figure 2E] FIG. 10 is a right side view of the cart in the highest position. [Figure 2F] FIG. 10 is a left side view of the cart in the highest position. [Figure 3A] FIG. 2 is a perspective view of a support column. [Figure 3B] FIG. 2 is a front view of the support column. [Figure 3C] FIG. 10 is a right side view of the support column. [Figure 3D] FIG. 10 shows a rear view of the support column. [Figure 4A] FIG. [Figure 4B] FIG. [Figure 5A] FIG. 2 is a perspective view of the top plate from below. [Figure 5B] FIG. 2 is a perspective view of the top plate from above. [Figure 6A] FIG. [Figure 6B] FIG. [Figure 6C] FIG. [Figure 6D] FIG. [Figure 6E] FIG. [Figure 6F] FIG. [Figure 6G] FIG. 2 is an exploded perspective view of the arm. [Figure 7A] FIG. 10 is a perspective view of a lower arm member. [Figure 7B] FIG. 10 is a right side view of the lower arm member. [Figure 8A] FIG. 10 is a perspective view of an upper arm member. [Figure 8B] FIG. 10 is a right side view of the upper arm member. [Figure 9] FIG. 2 is a perspective view of a telescopic device. [Figure 10A] FIG. 10 is a partial cross-sectional view of the cart when held in the highest position. [Figure 10B]FIG. 10 is a partial cross-sectional view of the cart when held in an intermediate position. [Figure 10C] FIG. 10 is a partial cross-sectional view of the cart when it is held in the lowest position. [Figure 10D] FIG. 10B is a superimposed view of partial cross sections of the cart of FIGS. 10A to 10C. [Figure 11] FIG. 10 is a right side view of the cart in the lowest position. [Figure 12] FIG. 10 is a diagram schematically illustrating a first modification of the cart. [Figure 13] FIG. 10 is a diagram schematically illustrating a second modified example of the cart. [Figure 14] FIG. 10 is a diagram schematically illustrating a third modified example of the cart. [Figure 15] FIG. 10 is a diagram schematically illustrating a fourth modified example of the cart. [Figure 16] FIG. 10 is a diagram schematically illustrating a fifth modified example of the cart. [Figure 17] FIG. 13 is a partial cross-sectional view of the cart according to the sixth modified example when it is held in the lowest position state. [Figure 18] FIG. 13 is a partial cross-sectional view of the cart according to Modification 7 when held in the highest position. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, a first embodiment of the lifting device according to the present invention will be described. In the first embodiment, the lifting device is configured as a nursing cart 1 that can travel on a floor. Fig. 1A is a perspective view of the nursing cart 1 from the front side, and Fig. 1B is a perspective view of the nursing cart 1 from the rear side.

[0014] For convenience, in the following description, various sides and directions (such as the front-to-back direction, the left-to-right direction, and the up-to-down direction) are identified based on the "front," "back," "left," "right," "up," and "down" shown in Fig. 1, but the relationship between these sides and directions and the sides and directions related to the nursing cart 1 is not limited to the first embodiment described below. In the following description, the nursing cart 1 will be simply referred to as "cart 1."

[0015] 2A is a diagram showing a front view of cart 1, FIG. 2B is a diagram showing a rear view of cart 1, FIG. 2C is a diagram showing a top view of cart 1, FIG. 2D is a diagram showing a bottom view of cart 1, FIG. 2E is a diagram showing a right side view of cart 1, and FIG. 2F is a diagram showing a left side view of cart 1.

[0016] As shown in Figures 1 and 2, cart 1 comprises a base 2, a support 3, an arm 4, a top plate support 5, a top plate 6, a pallet 7, and a pallet support member 8. Cart 1 contacts the floor surface at base 2. A support 3 is erected on base 2. The support 3 operably supports an arm 4 at its tip. The arm 4 operably supports, at its tip, a top plate support 5 to which a top plate 6 is attached. Furthermore, the support 3 supports, at its vertical center, the pallet support member 8 to which the pallet 7 is attached.

[0017] As will be described in detail later, the support column 3, arm 4, and tabletop support base 5 form a parallel link mechanism X. The cart 1 is configured so that, by operating the arm 4, the tabletop 6 can be raised and lowered continuously between the highest and lowest positions while maintaining the tabletop 6 in a horizontal position, and then fixed in place. Hereinafter, the state of the cart 1 in which the tabletop 6 is fixed at the highest position will be referred to as the "highest position state," and the state of the cart 1 in which the tabletop 6 is fixed at the lowest position will be referred to as the "lowest position state." Figures 1 and 2 show the cart 1 in the highest position state.

[0018] The base 2 includes a base body 20 and casters 21. The base body 20 includes a trunk 200 and four legs 201. The four legs 201 are formed by branching out from the trunk 200. The four legs 201 include a pair of left and right front legs 201A and a pair of left and right rear legs 201B.

[0019] The pair of left and right front legs 201A are formed to extend forward from the trunk 200. The pair of left and right rear legs 201B are formed to extend rearward from the trunk 200. The rear legs 201B are longer than the front legs 201A.

[0020] Casters 21 are attached to the tip of the lower surface 201A1 of the front leg 201A and to the tip of the lower surface 201B1 of the rear leg 201B. The casters 21 are configured to be rotatable 360 ​​degrees.

[0021] A support pillar 3 is erected at approximately the center in the front-to-rear and left-to-right directions of the upper surface 200S of the trunk 200. As described above, the rear leg 201B is longer than the front leg 201A, and therefore the position of the support pillar 3 in the front-to-rear direction is forward of the center of the base 2 in the front-to-rear direction.

[0022] Next, the support pillar 3 will be described. Fig. 3A is a perspective view of the support pillar 3, Fig. 3B is a front view of the support pillar 3, Fig. 3C is a right side view of the support pillar 3, and Fig. 3D is a rear view of the support pillar 3. As shown in Figs. 3A to 3D, the support pillar 3 comprises a support pillar main body 30, a support-side lower shaft member 31, and a support-side upper shaft member 32.

[0023] The support pillar body 30 is formed in the shape of a vertically elongated rectangular tube that is open at the top and has a bottom at the bottom. In other words, the support pillar 3 has a bottom plate portion 300, a front wall portion 301, a rear wall portion 302, a left wall portion 303, and a right wall portion 304.

[0024] The bottom plate 300 has a rectangular shape when viewed from the bottom. The front wall 301, rear wall 302, left wall 303, and right wall 304 are respectively provided vertically on the front edge, rear edge, left edge, and right edge of the upper surface of the bottom plate 300. The upper end 301T of the front wall 301 and the upper end 302T of the rear wall 302 are formed horizontally. The front wall 301 is higher than the rear wall 302. The left wall 303 and the right wall 304 are formed symmetrically.

[0025] A wiring hole 301h for passing wiring etc. is formed in approximately the center in the vertical direction of the front side wall portion 301. The wiring hole 301h has a substantially vertically elongated rectangular shape.

[0026] Three pallet receiving members 8 for mounting pallets 7 are attached at predetermined intervals in the vertical direction across the surfaces of the left side wall 303, rear side wall 302, and right side wall (see FIGS. 2A to 2F). A pallet 7 is attached to each pallet receiving member 8. When the pallet 7 is attached to the pallet receiving members 8, the position of the leading edge of the pallet 7 in the front-rear direction is approximately the same as the position of the leading edge of the rear leg 201B.

[0027] The support-side lower shaft member 31 and the support-side upper shaft member 32 are installed across the upper end of the left wall portion 303 and the upper end of the right wall portion 304. The cross-sectional shape of the support-side lower shaft member 31 and the support-side upper shaft member 32 perpendicular to the axial direction is circular. The support-side lower shaft member 31 and the support-side upper shaft member 32 are fixed so that their axial directions are parallel to the left-right direction (the support-side lower shaft member 31 and the support-side upper shaft member 32 extend in the left-right direction).

[0028] The support-side lower shaft member 31 is disposed above the upper end 302T of the rear wall portion 302. The support-side upper shaft member 32 is disposed diagonally above and on the front side of the support-side lower shaft member 31, at approximately the same vertical position (height) as the upper end 301T of the front wall portion 301. In a side view (for example, a right side view), the inclination angle θ1 (support-side inter-shaft inclination angle) of a line L1 connecting the central axis 31C (support-side lower central axis 31C) of the support-side lower shaft member 31 and the central axis 32C (support-side upper central axis 32C) of the support-side upper shaft member 32 with respect to a line L2 passing through the support-side upper central axis 32C and parallel to the front-rear direction is 30°. However, the support-side inter-shaft inclination angle θ1 is not limited and can be set appropriately.

[0029] An arm 4 is connected to (supported by) the support-side lower shaft member 31 and the support-side upper shaft member 32. As shown in Figures 1A and 1B, the arm 4 is generally formed in a columnar shape (extending in one direction). When the cart 1 is held in the highest position, the arm 4 extends obliquely upward and rearward from the support-side lower shaft member 31 and the support-side upper shaft member 32 as its base ends. The axial direction (extension direction) of the arm 4 is perpendicular to the straight line L1. The arm 4 will be described later.

[0030] Next, we will explain the top plate holder 5 that receives the top plate 6. Fig. 4A is a perspective view of the top plate holder 5, and Fig. 4B is a right side view of the top plate holder 5. As shown in Figs. 4A and 4B, the top plate holder 5 includes a top plate holder main body 50, a holder-side lower shaft member 51, and a holder-side upper shaft member 52.

[0031] The top plate receiving body 50 has a plate-shaped base portion 500 , a pair of plate-shaped side walls 501 on the left and right, and a plate-shaped rear wall portion 502 .

[0032] The base plate 500 has a rectangular shape in plan view. The short and long sides of this rectangle are parallel to the left-right and front-rear directions of the cart 1. Three bolt insertion holes 501h are formed at equal intervals along the long side of the base plate 500 on both edges of the short side. Bolts (not shown) for fastening the top plate 6 placed on the upper surface 500S1 of the base plate 500 are inserted into the bolt insertion holes 501h.

[0033] The pair of side walls 501 are erected vertically between bolt insertion holes 501h formed on both edges in the short side direction on the underside 500S2 of the base plate 500. The pair of side walls 501 face each other in the long side direction and are symmetrical (symmetrical with respect to a line passing through the center of the short side direction of the base plate 500 and parallel to the long side direction). The shape of the side walls 501 as viewed from the outside in the long side direction is a substantially right-angled scalene triangle.

[0034] The oblique side portions 501A of the side wall portions 501 are joined to the lower surface 500S2 of the base portion 500. When the top plate receiving base 5 is connected to the arm 4, the height portions 501B of the side wall portions 501 are disposed on the front side, and the bottom portions 501C of the side wall portions 501 are disposed on the rear side. A rear wall portion 502 is joined perpendicularly to the bottom portions 501C of the pair of side wall portions 501.

[0035] A catch-side lower shaft member 51 and a catch-side upper shaft member 52 are installed across a pair of side wall portions 501. The cross-sectional shape of the catch-side lower shaft member 51 and the catch-side upper shaft member 52 perpendicular to the axial direction is circular. The catch-side lower shaft member 51 and the catch-side upper shaft member 52 are fixed so that their axial directions are parallel to the left-right direction (the catch-side lower shaft member 51 and the catch-side upper shaft member 52 extend in the left-right direction). Therefore, the catch-side lower shaft member 51 and the catch-side upper shaft member 52 are parallel to the support-side lower shaft member 31 and the support-side upper shaft member 32.

[0036] The catch-side lower shaft member 51 is disposed at a corner portion 501D corresponding to a substantially right-angle portion of the side wall portion 501. The catch-side upper shaft member 52 is disposed closer to the base portion 500 than the catch-side lower shaft member 51 in the direction perpendicular to the base portion 500, and closer to the tip end of the height portion 501B than the catch-side lower shaft member 51 in the long side direction of the base portion 500 (on the opposite side to the rear wall portion 502), i.e., diagonally above and in front of the catch-side lower shaft member 51.

[0037] In addition, in a side view (for example, a right side view), the inclination angle (catch-side inter-axis inclination angle) θ2 of the straight line L3 connecting the central axis 51C (catch-side lower central axis 51C) of the catch-side lower shaft member 51 and the central axis 52C (catch-side upper central axis 52C) of the catch-side upper shaft member 52 with respect to the straight line L4 that passes through the catch-side upper central axis 52C and is parallel to the front-to-rear direction is the same as the support-side inter-axis inclination angle θ1. In other words, the catch-side inter-axis inclination angle θ2 is 30°. In addition, the straight line L3 is parallel to the height portion 501B.

[0038] Furthermore, the distance between the catch-side lower central axis 51C and the catch-side upper central axis 52C is the same as the distance between the support-side lower central axis 31C and the support-side upper central axis 32C.

[0039] Next, the table top 6 will be described. Fig. 5A is a perspective view of the table top 6 from below, and Fig. 5B is a perspective view of the table top 6 from above. As shown in Figs. 5A and 5B, the table top 6 has a table top main body 60, a handle 61, a handle receiving member 62, and an operating lever 63.

[0040] The tabletop body 60 is made of a flat plate formed in a rectangular shape in a plan view. As mentioned above, the tabletop 60 is kept horizontal when raised and lowered. The long side direction, short side direction, and thickness direction of the tabletop body 60 are parallel to the front-rear direction, left-right direction, and up-down direction of the cart 1, respectively.

[0041] Six bolt screw holes 60h are formed in the underside 60A of the tabletop main body 60, into which bolts (not shown) that fasten the tabletop holder 5 and the tabletop 6 are screwed. The positions of the six bolt screw holes 60h correspond to three bolt insertion holes 501h formed in each of both edges in the short side direction of the base plate portion 500. With the tabletop main body 60 bonded to the upper surface 500S1 of the base plate portion 500 of the tabletop holder main body 50 so that the six bolt screw holes 60h and the six bolt insertion holes 500h are connected in the thickness direction of the tabletop main body 60, bolts (not shown) are screwed into the bolt screw holes 60h from the side of the base plate portion 500 opposite to the tabletop main body 60, thereby fastening the tabletop 6 and the tabletop holder 5.

[0042] A pair of left and right handle receiving members 62 are attached to the rear end of the underside 60A of the tabletop main body 60. The pair of left and right handle receiving members 62 protrude rearward from the tabletop main body 60. A handle 61 is installed across the protruding portions of the pair of left and right handle receiving members 62. The handle 61 is rod-shaped overall and extends in the left-right direction. The left and right ends of the handle 61 are roughly aligned on both the left and right sides of the tabletop main body 60 in the front-to-rear direction. When the cart 1 is in the highest position, the front-to-rear position of the rear end of the tabletop main body 60 is approximately the same as the front-to-rear position of the rear end of the pallet 7 (see Figures 2E and 2F).

[0043] Furthermore, a manually operable operating lever 63 is provided on the underside 60A of the tabletop body 60, slightly forward of the handle receiving member 62 on the right edge. A wire (not shown) is connected to the operating lever 63, and the wire is connected to a lock lever 413 of the extension device 41, which will be described later. This lock lever 413 is configured to be operable. The lock lever 413 is operated by operating the operating lever 63. The lock function that fixes the length of the extension device 41 can be released / set by operating the lock lever 413.

[0044] The operating lever 63 is made of a plate-shaped member, and is basically biased so that its tip tilts inward in the left-right direction of the tabletop body 60. At this time, the locking function of the extension device 41 is set. When the tip of the operating lever 63 is pulled outward in the left-right direction, the wire is pulled and the locking function is released. Furthermore, when the hand is released from the operating lever 63 in this operated state, the biasing force returns the operating lever 63 to its state before operation, and the locking function is set.

[0045] Next, the arm 4 will be described. Fig. 6A is a front view of the arm 4, Fig. 6B is a rear view of the arm 4, Fig. 6C is a plan view of the arm 4, Fig. 6D is a bottom view of the arm 4, Fig. 6E is a right side view of the arm 4, Fig. 6F is a left side view of the arm 4, and Fig. 6G is an exploded perspective view of the arm 4. As shown in Figs. 6A to 6G, the arm 4 includes an arm main body 40 and an extension device 41.

[0046] As will be described later, arm 4 forms parallel link mechanism X in a plane perpendicular to the left-right direction, and therefore its posture changes. Therefore, views of arm 4 seen from the tabletop support 5 side and the support 3 side along the axial direction are respectively referred to as a front view and a bottom view, views seen from the right side and left side facing the support 3 side from the tabletop support 5 side are respectively referred to as a right side view and a left side view, and views seen from the floor side and from the opposite side of the floor via arm 4 are respectively referred to as a bottom view and a plan view.

[0047] The arm main body 40 is generally formed in the shape of a rectangular prism with both ends open. That is, the arm main body 40 has a hollow structure with a square cross section. The arm main body 40 also has a lower arm member 400 and an upper arm member 401. The lower arm member 400 and the upper arm member 401 are both generally formed with a U-shaped cross section. In the arm main body 40, the upper arm member 401 covers the lower arm member 400 from above, sandwiching it on both the left and right sides, so that the hollow portion 400S of the lower arm member 400 and the hollow portion 401S of the upper arm member 401 are connected to each other, resulting in an overall square cross section. The extension device 41 is stored inside the square cross section of the arm main body 40.

[0048] Therefore, the overall appearance of the arm 4 is almost entirely formed by the arm body 40. Therefore, the direction in which the lower arm member 400 and the upper arm member 401 are aligned is referred to as the "height direction," and the direction in which the ore is stored in the axial direction and height direction of the arm 4 is referred to as the "width direction."

[0049] In the arm 4, the lower arm member 400, the upper arm member 401, and the extension device 41 are not directly fixed to one another. As will be described later, the lower arm member 400, the upper arm member 401, and the extension device 41 are each connected to either the support-side lower shaft member 31 or the support-side upper shaft member 32 fixed to the support column main body 30, and also connected to either the receiver-side lower shaft member 51 or the receiver-side upper shaft member 52 fixed to the tabletop receiver main body 50, thereby forming an integral unit between the lower arm member 400, the upper arm member 401, and the extension device 41, and enabling the tabletop 6 to be raised and lowered as the arm 4.

[0050] Here, we will explain the lower arm member 400 and the upper arm member 401. Figure 7A is a perspective view of the lower arm member 400, and Figure 7B is a right side view of the lower arm member 400. Figure 8A is a perspective view of the upper arm member 401, and Figure 8B is a right side view of the upper arm member 401.

[0051] The lower arm member 400 has a lower bottom plate portion 400A having a vertically elongated rectangular shape in the axial direction of the arm body 40, and a pair of lower wall portions 400B bent at right angles in an arc shape from both edges of the lower bottom plate portion 400A.

[0052] A support-side lower shaft hole 400Bh1 into which the support-side lower shaft member 31 fits is formed at one end of the pair of lower wall portions 400B. The shape of the support-side lower shaft hole 400Bh1 is circular and is substantially the same as the cross-sectional shape perpendicular to the axial direction of the support-side lower shaft member 31. A catch-side lower shaft hole 400Bh2 into which the catch-side lower shaft member 51 fits is formed at the other end of the pair of lower wall portions 400B. The shape of the catch-side lower shaft hole 400Bh2 is circular and is substantially the same as the cross-sectional shape perpendicular to the axial direction of the catch-side lower shaft member 51.

[0053] The upper arm member 401 has an upper top panel portion 401A having a vertically elongated rectangular shape in the axial direction of the arm body 40, and a pair of upper wall portions 401B bent at right angles in the shape of circular arcs from both edges of the upper top panel portion 401A.

[0054] A support-side upper shaft hole 401Bh1 into which the support-side upper shaft member 32 fits is formed at one end of the pair of upper wall portions 401B. The shape of the support-side upper shaft hole 401Bh1 is circular and is substantially the same as the cross-sectional shape perpendicular to the axial direction of the support-side upper shaft member 32. A catch-side upper shaft hole 401Bh2 into which the catch-side upper shaft member 52 fits is formed at the other end of the pair of upper wall portions 401B. The shape of the catch-side upper shaft hole 401Bh2 is circular and is substantially the same as the cross-sectional shape perpendicular to the axial direction of the catch-side upper shaft member 52.

[0055] A line (lower arm member direction line) L5 ​​passing through the center C11 of the support-side lower shaft hole 400Bh1 and the center C12 of the catch-side lower shaft hole 400Bh2 is parallel to the extension direction of the lower arm member 400 (the axial direction of the arm 4). A line (upper arm member direction line) L6 passing through the center C21 of the support-side upper shaft hole 401Bh1 and the center C22 of the catch-side upper shaft hole 401Bh2 is parallel to the extension direction of the upper arm member 401 (the axial direction of the arm 4). Therefore, in the cart 1, the lower arm member direction line L5 and the upper arm member direction line L6 are parallel to each other. Furthermore, the distance between the center C11 of the support-side lower shaft hole 400Bh1 and the center C12 of the catch-side lower shaft hole 400Bh2 is the same as the distance between the center C21 of the support-side upper shaft hole 401Bh1 and the center C22 of the catch-side upper shaft hole 401Bh2.

[0056] 7A, 7B, 8A, and 8B, the arm main body 40 has been described as a standalone unit. Here, a description will be given of the arm main body 40 assembled into the cart 1. In the cart 1, the support-side lower shaft members 31 are fitted into both support-side lower shaft holes 400Bh1, and the support-side upper shaft members 32 are fitted into both support-side upper shaft holes 401Bh1. That is, the lower arm member 400 and the upper arm member 401 are integrally constrained at their base ends. In the cart 1, the catch-side lower shaft members 51 are fitted into both catch-side lower shaft holes 400Bh2, and the catch-side upper shaft members 52 are fitted into both catch-side upper shaft holes 401Bh2. That is, the lower arm member 400 and the upper arm member 401 are integrally constrained at their tip ends.

[0057] In this way, the lower arm member 400 and the upper arm member 401 are integrally constrained at both the base end side and the tip end side, so that with the inner surface of the upper wall portion 401B abutting against the outer surface of the lower wall portion 400B, the upper arm member 401 covers the lower arm member 400 from the tip side in the height direction of the lower wall portion 400B, and the lower arm member 400 and the upper arm member 401 form a closed cross section that is approximately square-shaped. In other words, the lower arm member 400 and the upper arm member 401 are not directly fixed to each other as the arm main body 40. The lower arm member 400 and the upper arm member 401 are integrated to form the arm main body 40 via the support-side lower shaft member 31 and the support-side upper shaft member 32 fixed to the column main body 30, and the receiver-side lower shaft member 51 and the receiver-side upper shaft member 52 fixed to the top plate receiver main body 50.

[0058] In the cart 1, the periphery of the support-side upper shaft hole 401Bh1 on the outer surface of the upper wall portion 401B abuts against the inner surfaces of the left side wall portion 303 and the right side wall portion 304. In addition, the periphery of the receiver-side upper shaft hole 401Bh2 on the outer surface of the upper wall portion 401B abuts against the inner surfaces of the pair of side wall portions 501. Therefore, the arm main body 40 is restricted from moving in the left-right direction by the support main body 30 and the top board receiver main body 50.

[0059] The center-to-center distance between the support-side lower shaft hole 400Bh1 and the catch-side lower shaft hole 400Bh2 of the lower arm member 400 is the same as the center-to-center distance between the support-side upper shaft hole 401Bh1 and the catch-side upper shaft hole 401Bh2 of the upper arm member 401. Furthermore, the distance between the catch-side lower central axis 51C and the catch-side upper central axis 52C is the same as the distance between the support-side lower central axis 31C and the support-side upper central axis 32C. Additionally, the support-side inter-shaft inclination angle θ1 and the catch-side shaft angle θ2 are the same. Therefore, the lower arm member directional line L5 and the upper arm member directional line L6 are parallel. The lower arm member 400 is rotatable in the circumferential direction about the support-side lower central axis 31C and the circumferential direction about the catch-side lower central axis 51C. On the other hand, the upper arm member 401 is rotatable in the circumferential direction about the support-side upper central shaft 32C, and is also rotatable in the circumferential direction about the catch-side upper central shaft 52C.

[0060] Therefore, as will be described in detail later, in a plane perpendicular to the left-right direction, the lower arm member 400 and the upper arm member 401 realize a parallel link mechanism X in which the first link X1, consisting of the straight portion between the support-side lower central axis 31C and the support-side upper central axis 32C formed in the support column main body 30, functions as a fixed node, and the second link X2, consisting of the straight portion between the receiver-side lower central axis 51C and the receiver-side upper central axis 52C formed in the tabletop receiver main body 50, functions as a connecting node. Therefore, by operating the parallel link mechanism X, the tabletop 6 is at a constant angle with respect to the left-right direction regardless of the position between the highest and lowest positions. In other words, the tabletop 6 is maintained in a horizontal state.

[0061] As links constituting the parallel link mechanism X, the straight line portion formed in the lower arm member 400 between the support side lower central axis 31C and the catch side lower central axis 51C is referred to as the "third link X3," and the straight line portion formed in the upper arm member 401 between the support side upper central axis 32C and the catch side upper central axis 52C is referred to as the "fourth link X4."

[0062] Next, the telescopic device 41 will be described. Figure 9 is a perspective view of the telescopic device 41. As shown in Figure 9, the telescopic device 41 has a telescopic main body 410, a cylinder side bracket 411, a piston side bracket 412, and a lock lever 413. The telescopic device 41 is configured with a publicly known (commercially available) gas spring with a locking function and rigidity specifications (KYB / FLF50-50, manufactured by Kayaba Corporation).

[0063] The telescopic body 410 has a cylinder 4100 and a piston rod 4101 that is partially stored inside the cylinder 4100. In addition to the piston rod 4101, the inside of the cylinder 4100 is filled with oil and nitrogen gas. The piston rod 4101 can move back and forth along the axial direction of the cylinder 4100. The more the piston rod 4101 protrudes from the cylinder 4100, the more the telescopic body 410 (telescopic device 41) extends, and the more the piston rod 4101 retracts into the cylinder 4100, the more the telescopic body 410 (telescopic device 41) contracts.

[0064] The cylinder side bracket 411 is fixed to the base end of the cylinder 4100. The cross section of the cylinder side bracket 411 perpendicular to the axial direction is U-shaped, and has a pair of cylinder side connection pieces 411K facing each other at close range. A cylinder side shaft insertion hole 411h into which the catch side upper shaft member 52 is inserted is formed in each cylinder side connection piece 411K. The shape of the cylinder side shaft insertion hole 411h is circular and is approximately the same as the cross section of the catch side upper shaft member 52 perpendicular to the axial direction.

[0065] The piston-side bracket 412 is fixed to the tip of the piston rod 4101. The piston-side bracket 412 has a U-shaped cross section perpendicular to the axial direction, and has a pair of piston-side connection pieces 412K facing each other at close range. Each piston-side connection piece 412K has a piston-side shaft insertion hole 412h into which the support-side lower shaft member 31 is inserted. The piston-side shaft insertion hole 412h has a circular shape, which is approximately the same as the cross section perpendicular to the axial direction of the support-side lower shaft member 31. Each piston-side connection piece 412K is formed parallel to each cylinder-side connection piece 411K.

[0066] The lock lever 413 is rod-shaped overall and is disposed between the pair of piston-side connection pieces 412K. One end of the lock lever 413 is exposed from the pair of piston-side connection pieces 412K. A notch 4130 is formed in the exposed portion for hooking and fixing the wire connected to the operating lever 63. The other end of the lock lever 413 is supported rotatably about a rotation axis perpendicular to the pair of piston-side connection pieces 412K.

[0067] The lock lever 413 shown in Figure 9 is in the set state. When the lock lever 413 is held in the set state, the lock function of the telescopic device 41 is set, and the extension and contraction of the telescopic device 41 (the reciprocating movement of the piston rod 4101) is completely restricted. In other words, the length of the telescopic device 41 is completely fixed. The lock lever 413 is basically held in the set state.

[0068] When the operating lever 63 is operated, one end of the lock lever 413 where the notch 4130 is formed is pulled by a wire (not shown) toward the cylinder 4100 (cylinder-side bracket 411) in the axial direction, causing the lock lever 413 to rotate (release rotation) so that the one end tilts toward the cylinder 4100 (cylinder-side bracket 411), and is locked, for example, at a rotation position perpendicular to the axial direction. When the lock lever 413 is held in this locked state, the locking function of the telescopic device 41 is released, allowing the telescopic device 41 to extend and retract (the piston rod 4101 to move back and forth).

[0069] Although detailed description is omitted, a biasing force is always applied to the lock lever 413 by a spring (not shown) or the like to return it to the set state. Therefore, when transitioning the lock lever 413 from the set state to the released state, the operating lever 63 is operated (to release and rotate the lock lever 413) while resisting this biasing force. If the operation of the operating lever 63 is released while the lock lever 413 is in the released state, the biasing force returns the lock lever 413 to the set state. As a result, the lock function is set again, and the extension and contraction of the telescopic device 41 (the reciprocating movement of the piston rod 4101) is completely restricted.

[0070] 9, the telescopic device 41 was described as a standalone device, but here we will explain the situation in which the telescopic device 41 is incorporated into the cart 1. In the cart 1, the support-side lower shaft member 31 is fitted into the pair of piston-side shaft fitting holes 412h of the telescopic device 41, and the catch-side upper shaft member 52 is fitted into the pair of cylinder-side shaft fitting holes 411h. In other words, the telescopic device 41 is installed across the support-side lower central shaft 31C and the catch-side upper central shaft 52C, and is connected to each of the support-side lower central shaft 31C and the catch-side upper central shaft 52C so as to be rotatable in the circumferential direction.

[0071] Therefore, when the locking function of the extension device 41 is set (when the extension device 41 is held in the set state), the extension device 41 cannot be extended or retracted at all, and therefore the operation of the parallel link mechanism X associated with the arm main body 40 (rotation of the lower arm member 400 at the support-side lower shaft member 31 and the catch-side lower shaft member 51, and rotation of the upper arm member 401 at the support-side upper shaft member 32 and the catch-side upper shaft member 52) is completely restricted. As a result, the tabletop 6 cannot be raised or lowered, and is held at the current up-and-down position (height).

[0072] Furthermore, when the locking function of the extension device 41 is released (when the extension device 41 is held in the released state), the extension device 41 can be extended or retracted, which allows the parallel link mechanism X associated with the arm main body 40 to freely operate (rotate the lower arm member 400 at the support-side lower shaft member 31 and the catch-side lower shaft member 51, and rotate the upper arm member 401 at the support-side upper shaft member 32 and the catch-side upper shaft member 52). As a result, the tabletop 6 can be raised or lowered, and the vertical position (height) of the tabletop 6 can be adjusted.

[0073] Next, a specific description will be given of the operation of the parallel link mechanism X associated with the arm body 40, the extension and contraction of the extension device 41, and the raising and lowering of the tabletop 6. Fig. 10A is a partial cross-sectional view of the cart 1 when the cart 1 is held in the highest position, Fig. 10B is a partial cross-sectional view of the cart 1 when the cart 1 is held in an intermediate state (intermediate position state) between the highest position state and the lowest position state, Fig. 10C is a partial cross-sectional view of the cart 1 when the cart 1 is held in the lowest position state, and Fig. 10D is a view in which the partial cross-sectional views of the cart 1 in Figs. 10A to 10C are superimposed.

[0074] As shown in FIG. 10A, when the cart 1 is held in the highest position, the telescopic device 41 is fully extended and the tabletop 6 is positioned at the highest position. At this time, the support-side inter-shaft tilt angle θ1 is 30°, so the tilt angle of the axial direction of the arm 4 relative to the floor (a straight line parallel to the front-to-rear direction) is 60°. As shown in FIG. 10B, when the cart 1 is held in the intermediate position, the telescopic device 41 is at a length intermediate between when it is fully extended and when it is fully retracted, and the tabletop 6 is positioned at a position intermediate between the highest and lowest positions (intermediate position). At this time, the angle of the arm 4 relative to the floor (a straight line parallel to the front-to-rear direction) is 30°. As shown in FIG. 10C, when the cart 1 is held in the lowest position, the telescopic device 41 is fully retracted and the tabletop 6 is positioned at the lowest position. At this time, the angle of the arm 4 relative to the floor (a straight line parallel to the front-to-rear direction) is 0°.

[0075] While the cart 1 transitions between the highest position and the lowest position, the second link X2 constituting the parallel link mechanism X via the arm body 40 is always kept parallel to the first link X1. The second link X2 formed by the tabletop support 5 moves in response to the movement of the arm 4, but the first link X1 formed by the support 3 is fixed to the floor surface (a straight line parallel to the front-to-rear direction), so the angle of the tabletop 6 supported by the tabletop support 5 with respect to the floor surface (a straight line parallel to the front-to-rear direction) is also always constant. Therefore, while the cart 1 transitions between the highest position and the lowest position, the angle of the tabletop 6 with respect to the floor surface (a straight line parallel to the front-to-rear direction) is kept at 0°; in other words, the tabletop 6 is kept horizontal.

[0076] Furthermore, when the cart 1 is in the highest position state, the stroke length of the piston rod 4101 is maximum. As the cart 1 transitions from the highest position state to the lowest position state, the stroke length of the piston rod 4101 gradually shortens. In the first embodiment, when the cart 1 is in the lowest position state, the stroke length of the piston rod 4101 associated with the telescopic device 41 is 0 cm. Therefore, working backwards, the stroke length of the piston rod 4101 in the highest position state must be set to a length that does not make the stroke length of the piston rod 4101 0 cm until the cart 1 reaches the lowest position state.

[0077] Furthermore, when the cart 1 is in the highest position, the front-to-rear direction position of the rear end of the tabletop main body 60 is approximately the same as the front-to-rear direction position of the rear end of the pallet 7. Here, the third link X3 (lower arm member 400) and the fourth link X4 (upper arm member 401) rotate integrally and synchronously, so the tabletop 6 gradually moves rearward as the cart 1 transitions from the highest position toward the lowest position. In the first embodiment, when the cart 1 is in the lowest position, the front-to-rear direction position of the rear end of the tabletop 6 is approximately rearward of the rear end of the pallet 7, and protrudes rearward from the rear tip of the pallet 7 by approximately one-third of the front-to-rear length of the tabletop 6. Note that FIG. 11 is a right side view of the cart 1 in the lowest position.

[0078] Furthermore, when in the lowest position, the stroke length of the piston rod 4101 associated with the extension device 41 is 0 cm, so a reaction force acts on the extension device 41 along the axial direction. Therefore, a load acts on the receiver-side upper shaft center 52C at an angle of 4° upward and rearward. As a result, the vertical component of this load acts as an assisting force when raising the tabletop 6. In other words, the extension device 41 has an assisting function when raising the tabletop 6 in addition to a locking function.

[0079] The direction of the load acting on the receiver side upper axis center 52C is the same as the inclination angle (tension / contraction inclination angle) of the straight line formed by the axial direction of the extension / contraction device 41, in other words, the straight line L7 connecting the support side lower central axis 31C and the receiver side upper central axis 52C with respect to a straight line parallel to the front-to-rear direction passing through the support side lower central axis 31C.

[0080] As described above, the cart 1 (lifting device) comprises the arm 4 including the arm body 40 which has a hollow structure over the entire axial length and a closed cross-sectional structure closed in the circumferential direction, the support column 3 (support body) which supports the arm 4, the top plate 6 (support object) which is the support target of the arm 4, and the top plate receiving seat 5 (receiving seat) which receives the top plate 6 (support object) and is supported by the arm 4, the support side lower shaft member 31 and the support side upper shaft member 32 which are arranged in parallel are fixed to the support column 3 (support body), and the receiving seat side lower shaft member 51 and the receiving seat side upper shaft member 52 which are arranged in parallel are fixed to the top plate receiving seat 5 (receiving seat), and the arm body 40 has the support side lower shaft member 31 and the receiving seat side upper shaft member 52 which are arranged in parallel at one end. The arm main body 40 is rotatably connected to both the support-side upper shaft member 32 and the catch-side lower shaft member 51, and is rotatably connected at its other end to both the catch-side lower shaft member 51 and the catch-side upper shaft member 52, and the support-side lower shaft member 31 and the support-side upper shaft member 32 and the catch-side lower shaft member 51 and the catch-side upper shaft member 52 together form a parallel link mechanism X (four-bar link mechanism), and operation of the parallel link mechanism X (four-bar link mechanism) allows the top board 6 (supported object) to be raised and lowered, and an extension device 41 is stored inside the arm main body 40, which is extendable and retractable following operation of the parallel link mechanism X (four-bar link mechanism) and can restrict operation of the parallel link mechanism X (four-bar link mechanism). The arm main body 40 itself, which constitutes a part of the parallel link mechanism X (four-bar link mechanism), has a closed cross-sectional structure that is closed in the circumferential direction, and the extension device 41 is stored inside the arm main body 40, which can restrict operation of the parallel link mechanism X (four-bar link mechanism). Therefore, fingers etc. will not be pinched in the arm 4 when the parallel link mechanism X (four-bar link mechanism) is activated. In addition, the appearance of the arm 4 will not be complicated. Therefore, deterioration in safety and aesthetic appearance can be suppressed.

[0081] Furthermore, according to the cart 1 (elevating device), the support-side lower shaft member 31 and the support-side upper shaft member 32 are parallel to the catch-side lower shaft member 51 and the catch-side upper shaft member 52, and the center-to-center distance between the support-side lower shaft member 31 and the support-side upper shaft member 32 is the same as the center-to-center distance between the catch-side lower shaft member 51 and the catch-side upper shaft member 52. The support-side lower shaft member 31 and the support-side upper shaft member 32 and the catch-side lower shaft member 51 and the catch-side upper shaft member 52 form a parallel link mechanism X. Therefore, the posture of the top plate 6 (supported object) remains constant while the top plate 6 (supported object) is raised or lowered. Therefore, the top plate 6 can be maintained horizontally regardless of the vertical position (height) at which the top plate 6 (supported object) is fixed, thereby improving the usability of the cart 1. Furthermore, according to the cart 1 (lifting device), the extension device 41 is rotatably connected to both the support-side lower shaft member 31 and the catch-side upper shaft member 52. Therefore, the parallel link mechanism X (four-bar link mechanism) can be reliably restrained. In addition, according to the cart 1 (lifting device), the arm body 40 has a lower arm member 400 arranged relatively lower and having a U-shaped cross section, and an upper arm member 401 arranged relatively upper and also having a U-shaped cross section, the lower arm member 400 and the upper arm member 401 being arranged symmetrically in a direction perpendicular to the axial direction, and the cross section perpendicular to the axial direction of the hollow structure of the arm body 40 is substantially rectangular. This simplifies the manufacture of the cart 1 (lifting device), particularly the arm 4, and shortens the manufacturing time.

[0082] <Example of change> Next, a modified example of the repair method according to the first embodiment will be described. The first embodiment described above can be modified as appropriate without departing from the spirit of the present invention. Note that parts configured in the same manner as in the first embodiment will be assigned the same reference numerals and detailed description will be omitted.

[0083] Fig. 12 is a diagram showing a first modification of the cart 1. As shown in Fig. 12, the arm body 40 according to the first modification is configured so that its axial length can be extended or contracted. Furthermore, the tabletop 6 according to the first modification is configured so that it can slide in the front-rear direction relative to the tabletop support 5.

[0084] FIG. 13 is a schematic diagram illustrating a second modification of the cart 1. As shown in FIG. 13, the tabletop body 60 according to the second modification includes a tabletop body front side 600 (front half), a tabletop body rear side 601 (rear half), and a hinge 602 connecting the tabletop body front side 600 and the tabletop body rear side 601. A rotation axis 601C of the hinge 602 is parallel to the left-right direction. The tabletop body rear side 601 is supported by a tabletop support 5. Therefore, the tabletop body rear side 601 is maintained horizontal between the highest position and the lowest position, but the tabletop body front side 600 can be tilted relative to the floor (a straight line parallel to the front-to-rear direction). Note that the tabletop body front side 600 may be supported by the tabletop support 5, and the tabletop body rear side 601 may be maintained horizontal between the highest position and the lowest position, allowing it to be tilted relative to the floor (a straight line parallel to the front-to-rear direction).

[0085] Fig. 14 is a diagram schematically illustrating a third modification of the cart 1. As shown in Fig. 14, the support column body 30 according to the third modification is configured to be extendable in the vertical direction, and the entire parallel link mechanism X can be raised and lowered in accordance with the extension and contraction.

[0086] Fig. 15 is a diagram showing a fourth modified example of the cart 1. As shown in Fig. 15, the table top 6 according to the fourth modified example is configured to be rotatable in the circumferential direction relative to the table top holder 5. In this case, the axis of rotation is parallel to the left-right direction.

[0087] FIG. 16 is a schematic diagram illustrating a fifth modification of the cart 1. As shown in FIG. 16, the cart 1 according to the fifth modification includes a pair of legs 9 extending in the front-rear direction, a pair of support columns 3 extending in the up-down direction and erected vertically from approximately the center of the front-rear direction of the upper surface of each leg 9, a pair of arms 4 connected to the tip of each support column 3 in the same manner as in the first embodiment, a pair of tabletop support seats 5 connected to the tip of each arm 4 in the same manner as in the first embodiment, a tabletop 6 joined to the pair of tabletop support seats 5, and a fixing member 90 installed across the inner surfaces of both legs 9 at approximately the center of the front-rear direction. Note that the connection structure between the arms 4, the support columns 3, and the tabletop support seats 5 according to the fifth modification is the same as that of the first embodiment. That is, the number of parallel link mechanisms X each consisting of the support columns 3, the arms 4, and the tabletop support seats 5 may be plural.

[0088] FIG. 17 is a partial cross-sectional view of the cart according to the sixth modified example when held in the lowest position. As shown in FIG. 17, a lower-arm inner shaft member 42 is provided on the lower arm member 400, spanning both of the pair of lower wall portions 400B and parallel to the width direction (support-side lower shaft member 31, etc.). The lower-arm inner shaft member 42 is formed slightly axially distal from the support-side lower shaft hole 400Bh1 in the lower wall portion 400B in a side view. Furthermore, an upper-arm inner shaft member 43 is provided on the upper arm member 401, spanning both of the pair of upper wall portions 401B and parallel to the width direction (support-side lower shaft member 31, etc.). The upper-arm inner shaft member 43 is formed slightly axially proximal from the catch-side upper shaft hole 401Bh2 in the upper wall portion 401B in a side view.

[0089] An extension device 41', which has a locking mechanism with the same rigidity and extendability as the extension device 41 but is a smaller version of the extension device 41, is rotatably connected to the lower-arm inner shaft member 42 and the upper-arm inner shaft member 43. The extension device 41' has a locking mechanism with the same rigidity and extendability as the extension device 41, but is a smaller version of the extension device 41. The inclination angle of the extension device 41' relative to a line in the axial direction (i.e., the line connecting the center 42C of the lower-arm inner shaft member 42 and the center 43C of the upper-arm inner shaft member 43) passing through the center 42C of the lower-arm inner shaft member 42 and parallel to the axial direction of the arm 4) is greater than the inclination angle of the extension device 41 according to the first embodiment. Therefore, for example, when the cart 1 according to the sixth modification is in the lowest position, the vertical component of the load acting on the upper-arm inner shaft member 43 is greater than that of the first embodiment, improving the assist function when raising the tabletop 6.

[0090] As a further modification of the sixth modification of the cart 1, the upper arm inner shaft member 43 may not be provided, and the extension device 41′ may be configured to be rotatably connected to both the lower arm inner shaft member 42 and the receiver side upper shaft member 52. Alternatively, the lower arm inner shaft member 42 may not be provided, and the extension device 41′ may be configured to be rotatably connected to both the support side lower shaft member 31 and the upper arm inner shaft member 43.

[0091] FIG. 18 is a partial cross-sectional view of the cart according to the seventh modified example when held in the highest position. As shown in FIG. 18, an upper-arm inner shaft member 45 is installed on the upper arm member 401, straddling both of the pair of upper wall portions 401B and parallel to the width direction (support-side lower shaft member 31, etc.). In a side view, the upper-arm inner shaft member 45 is located slightly axially distal to the support-side upper shaft hole 401Bh1 in the upper wall portion 401B. Furthermore, a support-side intermediate shaft member 36 is installed on the support column 3, straddling the left wall portion 303 and the right wall portion 304 and parallel to the left-right direction (support-side lower shaft member 31, etc.). In a side view, the support-side intermediate shaft member 36 is located approximately midway between the support-side lower shaft member 31 and the support-side upper shaft member 32 in the front-rear direction and below the support-side lower shaft member 31.

[0092] 18, the cart 1 according to the seventh modified example is provided with an extension device 4" that is smaller overall than the extension device 41 according to the first embodiment but has the same function. The extension device 4" is installed across the support main body 30 and the arm main body 40. Specifically, the extension device 4" is rotatably connected to the support-side intermediate shaft member 36 and the upper-arm inner shaft member 45, just like the extension device 41. In this way, the extension device 4" that has a locking function for the operation of the parallel link mechanism X and an assist function for lifting the tabletop 6 may be partially stored in the support main body 30 and partially stored in the arm main body 40.

[0093] Furthermore, in the first embodiment, the cross-sectional shape of the arm main body 40 perpendicular to the axial direction is square, but is not particularly limited to this and may be set as appropriate as long as the entire arm main body 40 has a closed cross-sectional structure. Furthermore, the arm main body 40 is configured such that the upper arm member 401 covers the lower arm member 400 from the tip side in the height direction of the lower wall portion 400B with the inner surface of the upper wall portion 401B abutting against the outer surface of the lower wall portion 400B, but the arm main body 40 may be configured such that the lower arm member 400 covers the upper arm member 401 from the tip side in the height direction of the upper wall portion 401B with the inner surface of the lower wall portion 400B abutting against the outer surface of the upper wall portion 401B arranged above. Alternatively, the arm main body 40 may be configured so that the lower arm member 400 and the upper arm member 401 are joined together with the heightwise end of the lower wall portion 400B butting against the heightwise end of the upper wall portion 401B.

[0094] In the first embodiment, the receiver-side upper shaft member 52 is fitted into the cylinder-side shaft fitting hole 411h of the extension device 41, and the support-side lower shaft member 31 is fitted into the piston-side shaft fitting hole 412h. However, the receiver-side lower shaft member 51 may be fitted into the cylinder-side shaft fitting hole 411h, and the support-side upper shaft member 32 may be fitted into the piston-side shaft fitting hole 412h. Furthermore, the extension device 41 may be disposed inside the arm main body 40 so that the support-side lower shaft member 31 is fitted into the cylinder-side shaft fitting hole 411h, and the receiver-side upper shaft member 52 is fitted into the piston-side shaft fitting hole 412h. Alternatively, the extension device 41 may be disposed inside the arm main body 40 so that the support-side upper shaft member 32 is fitted into the cylinder-side shaft fitting hole 411h, and the receiver-side lower shaft member 52 is fitted into the piston-side shaft fitting hole 412h.

[0095] Furthermore, the direction of the load acting on the catch-side upper axis center 52C when the cart 1 is in the lowest position is based on the telescopic tilt angle, but this telescopic tilt angle is related to the ratio (flat ratio) of the center-to-center distance between the support-side lower central axis 31C and the support-side upper central axis 32C (or the center-to-center distance between the catch-side lower central axis 51C and the catch-side upper central axis 52C) to the center-to-center distance between the support-side lower central axis 31C and the catch-side lower central axis 51C (or the center-to-center distance between the support-side upper central axis 32C and the catch-side lower central axis 52C). This flat ratio may be changed as appropriate. In other words, the telescopic tilt angle may be changed as appropriate.

[0096] Furthermore, although the telescopic device 41 is configured with a gas spring, its structure is not particularly limited and may be modified as appropriate as long as it is capable of expanding and contracting in response to the operation of the parallel link mechanism X and has a function of restricting the expansion and contraction. For example, in the first embodiment, when the locking function of the telescopic device 41 is set, the length of the telescopic device 41 is completely fixed. However, the length of the telescopic device 41 may have some so-called "play" and the telescopic device 41 may be able to expand and contract by a few millimeters. In other words, the locking function of the telescopic device 41 may be configured to substantially (approximately) restrict the expansion and contraction of the telescopic device 41 (approximately fix the length of the telescopic device 41) rather than completely restricting the expansion and contraction of the telescopic device 41 (completely fixing the length of the telescopic device 41). Alternatively, the locking mechanism of the telescopic device 41 may be configured with an elastic specification. Furthermore, the telescopic device 41 may be configured with a telescopic device having a locking function other than a gas spring.

[0097] In addition, in the first embodiment, the extension device 41 has both a locking function and an assisting function, but an extension device with a locking function and an extension device with an assisting function may be provided separately.

[0098] In addition, in the first embodiment, the parallel link mechanism X is composed of the support 3, the arm 4, and the top plate support 5, but a four-bar link mechanism other than the parallel link mechanism X may be constructed as long as it is configured to be able to raise and lower the object supported by the arm 4.

[0099] Furthermore, the cart 1 is provided with four casters 21 and is configured to be movable, but the number of casters 21 is not limited to four. Furthermore, the means for moving the cart 1 is not limited to the casters 21.

[0100] Furthermore, the arm 4 supports the tabletop 6 via the tabletop support 5, but the object to be supported is not limited to the tabletop 6 and can be set as appropriate. For example, the arm 4 may support a mobile information terminal such as a tablet or a monitor via the tabletop support 5. In this case, the mobile information terminal or monitor may be held parallel to a plane perpendicular to the up-down direction, as in the first embodiment. Alternatively, the mobile information terminal or monitor may be held parallel to a plane perpendicular to the front-to-back direction (perpendicular to the floor).

[0101] Furthermore, although the lifting device according to the present invention is configured with a cart 1, it may be configured with equipment other than the cart 1, provided that the supported object can be raised and lowered. For example, in cart 1 as one form of the lifting device according to the present invention, arm 4 is rotatably supported by support 3, but the lifting device according to the present invention may not have support 3, and arm 4 may be rotatably supported by a support other than support 3, such as a floor or a table. Furthermore, the lifting device according to the present invention may not have moving means such as casters 21 and may be configured to be immobile.

[0102] It should be noted that the present embodiment is merely an example and does not limit the present invention in any way. Naturally, the present invention can be modified in various ways without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0103] 1...Cart (lifting device) 3... Pillar (support), 4... Arm, 5... Top plate seat (seat), 6... Top plate (supported object) 30... Support column body, 31... Support side lower shaft member, 32... Support side upper shaft member 40... arm body, 41... telescopic device 50...top plate receiving seat main body, 51...support side lower shaft member, 52...receiving seat side upper shaft member 63...Operating lever X...Parallel link mechanism

Claims

1. The arm includes an arm body having a hollow structure over the entire axial length and a closed cross-sectional structure that is closed in the circumferential direction, a support body that supports the arm, a support object that is an object to be supported by the arm, and a seat that receives the support object and is supported by the arm, A support-side lower shaft member and a support-side upper shaft member arranged in parallel are fixed to the support body, A catch-side lower shaft member and a catch-side upper shaft member arranged in parallel are fixed to the catch, the arm body is rotatably connected at one end to both the support-side lower shaft member and the support-side upper shaft member, and at the other end to both the catch-side lower shaft member and the catch-side upper shaft member, the support-side lower shaft member, the support-side upper shaft member, the catch-side lower shaft member, and the catch-side upper shaft member constitute a four-joint link mechanism, The four-bar link mechanism is actuated to lift and lower the supported object, A lifting device characterized in that an extension device is stored inside the arm body, which can extend and retract in response to the operation of the four-bar link mechanism and can restrict the operation of the four-bar link mechanism.

2. The lifting device according to claim 1, the support-side lower shaft member and the support-side upper shaft member are parallel to the catch-side lower shaft member and the catch-side upper shaft member, and the center-to-center distance between the support-side lower shaft member and the support-side upper shaft member is the same as the center-to-center distance between the catch-side lower shaft member and the catch-side upper shaft member, The lifting device is characterized in that the support-side lower shaft member, the support-side upper shaft member, the catch-side lower shaft member, and the catch-side upper shaft member form a parallel link mechanism.

3. The lifting device according to claim 1, The lifting device is characterized in that the extension device is rotatably connected to both the support side lower shaft member and the receiver side upper shaft member, or to both the support side upper shaft member and the receiver side lower shaft member.

4. The lifting device according to claim 1, The arm body has a lower arm member disposed relatively lower and having a U-shaped cross section, and an upper arm member disposed relatively upper and also having a U-shaped cross section, A lifting device characterized in that the lower arm member and the upper arm member are arranged symmetrically in a direction perpendicular to the axial direction, and the cross-sectional shape perpendicular to the axial direction of the hollow structure of the arm main body is approximately rectangular.

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