Transport trolley

Abstract

To provide a transportation dolly that is able to reduce the size of an electric actuator serving as a drive source for lifting / lowering a load-carrying platform.SOLUTION: A transportation dolly has: a movable body 93 that is driven and moved by an electric actuator 91; a first link member 951r (951L) connected to the movable body 93; a second link member 953R (953L) connected to the first member 951R (951L) via a shaft member 952R (952L) and connected to a pair of X-shaped arms 71L, 71R (75L, 75R), left and right; and a guide member 97R (97L) having a guide hole 971R (971L) that guides movement of the shaft member 952R (952L) caused by movement of the movable body 93. A load-carrying platform 50 is lifted / lowered by vertically extending / shortening the pair of X-shaped arms, left and right, via the first and second link members 951R, 951L (953R, 953L) by movement of the movable body 93.SELECTED DRAWING: Figure 14

Description

Technical Field

[0001] The present invention relates to a carrier truck capable of raising and lowering a loading platform.

Background Art

[0002] As an example of this type of carrier truck, Patent Document 1 describes a carrier truck in which a lift arm (X-shaped arm) is telescopically driven by an electric cylinder (electric actuator) to raise and lower a loading platform.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a configuration in which an X-shaped arm is telescopically driven to raise and lower a loading platform, usually, a larger force is required to raise the loading platform in the lowest position than at other times. For this reason, when an electric actuator is used as a drive source for raising and lowering the loading platform, it is necessary to employ an electric actuator capable of exerting the output required to raise the loading platform in the lowest position with a load placed thereon, and it has not been easy to miniaturize the electric actuator.

[0005] Therefore, an object of the present invention is to provide a carrier truck that enables miniaturization of an electric actuator as a drive source for raising and lowering a loading platform.

Means for Solving the Problems

[0006] According to one aspect of the present invention, a carrier truck is provided. The carrier truck includes a base having wheels attached to a lower portion thereof, a loading platform disposed above the base, and a pair of telescopic members provided between the base and the loading platform and capable of expanding and contracting in a vertical direction One pair of First left sideX-shaped arm And the first right X-shaped arms and a drive device configured to raise and lower the loading platform by expanding and contracting the First left side X-shaped arm And the first right X-shaped arms . Each of the first left X-shaped arm and the first right X-shaped arm has two arms that cross in an X shape in a side view and are combined so as to be relatively rotatable with respect to each other. One end of one of the two arms of the first left X-shaped arm is rotatably attached near the left end of a connecting shaft extending in the left-right direction, and one end of the arm corresponding to the one arm of the first left X-shaped arm among the two arms of the first right X-shaped arm is rotatably attached near the right end of the connecting shaft. In the transport cart, the drive device includes an electric actuator, a movable body driven by the electric actuator to In the front-rear direction move, a first link member having one end rotatably connected to the movable body, and one end being rotatably connected to the Connecting shaft and the other end being rotatably connected to the other end of the first link member via a shaft member, and a guide for guiding the movement of the shaft member accompanying the movement of the movable body Hole or guide groove formed on a guide member. The movement of the movable body causes the First left side X-shaped arm And the first right X-shaped arms to expand and contract in the vertical direction , The guide hole or the guide groove is formed to be curved in a substantially U shape so that the shaft member is moved obliquely downward and then obliquely upward as the movable body moves in the direction of raising the loading platform. .

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a transport cart that enables miniaturization of an electric actuator as a drive source for raising and lowering a loading platform.

Brief Description of the Drawings

[0008]

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

Figure 15

Figure 16

Figure 17

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

[0010] FIGS. 1 to 4 show the configuration of a transport trolley 10 with a handrail according to an embodiment of the present invention. FIG. 1 is a view of the transport trolley 10 as seen from the front, FIG. 2 is a view of the transport trolley 10 as seen from the rear, FIG. 3 is a view of the transport trolley 10 as seen from the right side, and FIG. 4 is a view of the transport trolley 10 as seen from the left side.

[0011] As shown in FIGS. 1 to 4, the transport trolley 10 according to the embodiment includes a base 30, a handrail (hereinafter simply referred to as "rail") 40, a loading platform 50 disposed above the base 30, a telescopic mechanism 70 provided between the base 30 and the loading platform 50, a drive device 90 that drives (extends and retracts) the telescopic mechanism 70, and a control device 100 that controls the drive device 90.

[0012] FIG. 5 is a perspective view mainly showing the base 30 and the handle 40 of the transport cart 10. As shown in FIG.

[0013] 5, the base 30 is formed as a rectangular frame. The base 30 has a front frame member 31A and a rear frame member 31B that extend in the left-right direction, and a pair of left and right frame members (a left frame member 32L and a right frame member 32R) that extend in the front-rear direction. Free caster wheels (front wheels) 33, 33 are attached to the lower parts of the two front corners of the base 30, and electric drive wheels (rear wheels) 34, 34, each incorporating an in-wheel motor, for example, are attached to the lower parts of the two rear corners.

[0014] In the base 30, a left rail portion 35L extending in the front-rear direction is provided on the inner surface of the front side of the left frame member 32L, and a right rail portion 35R paired with the left rail portion 35L is provided on the inner surface of the front side of the right frame member 32R. In addition, a pair of mounting portions (a left mounting portion 36L and a right mounting portion 36R) spaced apart in the left-right direction are provided on the rear side of the base 30. Furthermore, an installation portion 37 on which the drive unit 90 and the control unit 100 are installed is provided inside the base 30 and at a position lower than the base 30.

[0015] The handle 40 is attached to the rear frame member 31B in an upright position. The handle 40 is made of, for example, a pipe material and is formed in a generally gate-like shape (a generally inverted U-shape). Specifically, the handle 40 has a pair of left and right support portions 41, 41 that extend generally vertically upward from the rear frame member 31B and then extend obliquely rearward, and a grip portion 43 that extends generally horizontally between the tips of the pair of left and right support portions 41, 41. The grip portion 43 is a part that is mainly gripped by a worker or the like who uses the transport cart 10 (hereinafter simply referred to as "worker").

[0016] Returning to FIGS. 1 to 4, the loading platform 50 has a rectangular top plate portion 51 on which luggage (not shown) is placed on the upper surface, and a peripheral wall portion 53 hanging down from the peripheral edge portion of the top plate portion 51. On the front side of the lower surface of the top plate portion 51, a pair of left and right rail members (left rail member 55L and right rail member 55R) each having a rail groove are provided, and on the rear side of the lower surface of the top plate portion 51, a pair of mounting portions (left mounting portion 56L and right mounting portion 56R) spaced apart in the left-right direction are provided projecting.

[0017] The telescopic mechanism 70 is configured to raise and lower the loading platform 50 in a state parallel to the base 30 by the telescopic movement in the vertical direction of a pair of left and right X-shaped arms (also called pantograph arms). Here, the telescopic mechanism 70 is usually telescoped when the transport cart 10 is on a horizontal plane, that is, when the base 30 is in a horizontal state. For this reason, it can also be said that the telescopic mechanism 70 is configured to raise and lower the loading platform 50 in a horizontal state by the telescopic movement in the vertical direction of a pair of left and right X-shaped arms. In the present embodiment, the telescopic mechanism 70 is formed as an X-shaped link mechanism having a two-stage structure in which a pair of left and right X-shaped arms are stacked vertically.

[0018] FIGS. 6 to 8 show the configuration of the telescopic mechanism 70. FIG. 6 is a view of the telescopic mechanism 70 seen from the right side, FIG. 7 is a view of the telescopic mechanism 70 seen from the left side, and FIG. 8 is a perspective view of the telescopic mechanism 70.

[0019] As shown in FIGS. 6 to 8, in the present embodiment, the telescopic mechanism 70 includes a pair of left and right X-shaped arms on the lower stage side (left lower X-shaped arm 71L and right lower X-shaped arm 71R), and a pair of left and right X-shaped arms on the upper stage side (left upper X-shaped arm 75L and right upper X-shaped arm 75R).

[0020] Each of the left lower X-shaped arm 71L and the right lower X-shaped arm 71R, which are a pair of left and right X-shaped arms on the lower stage side, is formed by combining a lower inner arm and a lower outer arm that cross each other in an X shape in a side view and are relatively rotatable with respect to each other. Specifically, in the present embodiment, the left lower X-shaped arm 71L is configured such that the central portion of the lower inner arm 72L and the central portion of the lower outer arm 74L are each rotatably attached in the vicinity of the left end portion of a lower connecting shaft 81 that extends in the left-right direction (see FIGS. 7 and 8). Similarly, the right lower X-shaped arm 71R is configured such that the central portion of the lower inner arm 72R and the central portion of the lower outer arm 74R are each rotatably attached in the vicinity of the right end portion of the lower connecting shaft 81 (see FIGS. 6 and 8).

[0021] Each of the left upper X-shaped arm 75L and the right upper X-shaped arm 75R, which are a pair of left and right X-shaped arms on the upper stage side, is also formed by combining an upper inner arm and an upper outer arm that cross each other in an X shape in a side view and are relatively rotatable with respect to each other. Specifically, in the present embodiment, the left upper X-shaped arm 75L is configured such that the central portion of the upper inner arm 76L and the central portion of the upper outer arm 78L are each rotatably attached in the vicinity of the left end portion of an upper connecting shaft 82 that extends in the left-right direction above the lower connecting shaft 81 (see FIGS. 7 and 8). Similarly, the right upper X-shaped arm 75R is configured such that the central portion of the upper inner arm 76R and the central portion of the upper outer arm 78R are each rotatably attached in the vicinity of the right end portion of the upper connecting shaft 82 (see FIGS. 6 and 8).

[0022] And the pair of left and right X-shaped arms on the lower stage side (left lower X-shaped arm 71L and right lower X-shaped arm 71R) and the pair of left and right X-shaped arms on the upper stage side (left upper X-shaped arm 75L and right upper X-shaped arm 75R) are connected via a rear connecting shaft 83 and a front connecting shaft 84 that extend in the left-right direction.

[0023] Specifically, in the present embodiment, the rear end portions of the lower inner arm 72L constituting the lower left X-shaped arm 71L and the upper outer arm 78L constituting the upper left X-shaped arm 75L are rotatably attached near the left end of the rear connecting shaft 83 (see FIGS. 7 and 8), and the rear end portions of the lower inner arm 72R constituting the lower right X-shaped arm 71R and the upper outer arm 78R constituting the upper right X-shaped arm 75R are rotatably attached near the right end of the rear connecting shaft 83 (see FIGS. 6 and 8).

[0024] Further, the front end portions of the lower outer arm 74L constituting the lower left X-shaped arm 71L and the upper inner arm 76L constituting the upper left X-shaped arm 75L are rotatably attached near the left end of the front connecting shaft 84 (see FIGS. 7 and 8), and the front end portions of the lower outer arm 74R constituting the lower right X-shaped arm 71R and the upper inner arm 76R constituting the upper right X-shaped arm 75R are rotatably attached near the right end of the front connecting shaft 84 (see FIGS. 6 and 8).

[0025] The front end portion of the lower inner arm 72L constituting the lower left X-shaped arm 71L is rotatably attached inside the left end of the lower moving shaft 85 that extends in the left-right direction below the front connecting shaft 84 and is movable in the front-rear direction (see FIGS. 7 and 8), and the front end portion of the lower inner arm 72R constituting the lower right X-shaped arm 71R is rotatably attached inside the right end of the lower moving shaft 85 (see FIGS. 6 and 8).

[0026] The left end of the lower moving shaft 85 is inserted into the left rail portion 35L provided on the left frame member 32L of the base 30, and the right end of the lower moving shaft 85 is inserted into the right rail portion 35R provided on the right frame member 32R of the base 30 (see FIGS. 3 to 8). That is, in the present embodiment, both ends of the lower moving shaft 85 are supported by the left rail portion 35L and the right rail portion 35R provided on the base 30, and it is configured to be movable in the front-rear direction along the left rail portion 35L and the right rail portion 35R.

[0027] Also, the rear end portion of the lower outer arm 74L constituting the left lower X-shaped arm 71L is rotatably fixed to the left attachment portion 36L provided on the rear side of the base 30 via the pin member P1, and the rear end portion of the lower outer arm 74R constituting the right lower X-shaped arm 71R is rotatably fixed to the right attachment portion 36R provided on the rear side of the base 30 via the pin member P1 (see FIGS. 3 to 8).

[0028] The front end portion of the upper outer arm 78L constituting the left upper X-shaped arm 75L is rotatably attached inside the left end portion of the upper moving shaft 86 that extends in the left-right direction above the front connecting shaft 84 and is movable in the front-rear direction (see FIGS. 7 and 8), and the front end portion of the upper outer arm 78R constituting the right upper X-shaped arm 75R is rotatably attached inside the right end portion of the upper moving shaft 86 (see FIGS. 6 and 8).

[0029] The left end of the upper moving shaft 86 is inserted into the rail groove of the left rail member 55L provided on the lower surface of the loading platform 50 (the top plate portion 51), and the right end of the upper moving shaft 86 is inserted into the rail groove of the right rail member 55R that is paired with the left rail member 55L and is provided on the lower surface of the loading platform 50 (the top plate portion 51) (see FIGS. 1 to 4, FIGS. 6 to 8). That is, in the present embodiment, both ends of the upper moving shaft 86 are supported by the left rail member 55L and the right rail member 55R provided on the lower surface of the loading platform 50, and it is configured to be movable in the front-rear direction along the rail groove of the left rail member 55L and the rail groove of the right rail member 55R.

[0030] The rear end of the upper inner arm 76L that constitutes the upper left X-shaped arm 75L is rotatably fixed via a pin member P2 to a left mounting portion 56L protruding from the lower surface of the loading platform 50 (the top plate portion 51 thereof) (see FIGS. 2, 4, 6 to 8). Further, the rear end of the upper inner arm 76R that constitutes the upper right X-shaped arm 75R is rotatably fixed via a pin member P2 to a right mounting portion 56R that projects from the lower surface of the loading platform 50 (the top plate portion 51 thereof) and is paired with the left mounting portion 56L (see FIGS. 2, 3, 6 to 8).

[0031] The drive device 90 is installed in an installation portion 37 provided inside the base 30 and one step lower than the base 30. The drive device 90 is configured to vertically expand and contract a pair of left and right X-shaped arms on the lower stage side (the left lower X-shaped arm 71L and the right lower X-shaped arm 71R) and a pair of left and right X-shaped arms on the upper stage side (the left upper X-shaped arm 75L and the right upper X-shaped arm 75R) that constitute the expansion and contraction mechanism 70, thereby raising and lowering the loading platform 50.

[0032] FIGS. 9 to 11 show the configuration of the drive device 90. FIG. 9 is a view of the drive device 90 as seen from the right side, FIG. 10 is a view of the drive device 90 as seen from the left side, and FIG. 11 is a view A of FIG. 9.

[0033] As shown in FIGS. 9 to 11, in the present embodiment, the drive device 90 includes an electric actuator 91, a movable body 93 that is driven by the electric actuator 91 to move, a pair of left and right link mechanisms (the left link mechanism 95L, the right link mechanism 95R) as a connection mechanism that connects the movable body 93 and the expansion and contraction mechanism 70, and a pair of left and right guide members (the left guide member 97L, the right guide member 97R).

[0034] The electric actuator 91 is a linear actuator that converts the rotational motion of an electric motor into linear motion by a linear motion mechanism (e.g., a ball screw mechanism) and outputs it. In this embodiment, the electric actuator 91 includes an electric motor (servo motor) 911, a speed reduction mechanism 913, and a linear motion mechanism (linear motion shaft (screw shaft) 915A and linear motion nut 915B).

[0035] The operation of the electric motor 911 is controlled by the control device 100. An unexcited operation type brake 912 is attached to the output shaft of the electric motor 911 via, for example, a coupling, and an encoder (rotation sensor) 914 that detects the rotation of the electric motor 911 and outputs a signal is attached to the electric motor 911.

[0036] The speed reduction mechanism 913 reduces the rotation of the output shaft of the electric motor 911 and transmits it to the linear motion shaft 915A of the linear motion mechanism. The configuration of the speed reduction mechanism 913 is not particularly limited. The speed reduction mechanism 913 may be a single-stage speed reduction mechanism or a multi-stage speed reduction mechanism.

[0037] The linear motion shaft 915A extends in the front-rear direction and is rotatably supported by support members 916A and 916B to which bearings (not shown) are attached. The linear motion shaft 915A is rotationally driven by the electric motor 911 via the speed reduction mechanism 913. The linear motion nut 915B is screwed onto the linear motion shaft 915A and moves axially on the linear motion shaft 915A (i.e., linearly moves in the front-rear direction) as the linear motion shaft 915A rotates.

[0038] The movable body 93 is fixed to the linear motion nut 915B and moves integrally with the linear motion nut 915B. In this embodiment, a linear slider 94 is installed below the linear motion shaft 915A. The linear slider 94 has a slide rail 94A extending in the front-rear direction and a slide block 94B that moves on the slide rail 94A. The lower part of the movable body 93 fixed to the linear motion nut 915B is fixed to the slide block 94B.

[0039] As the left link mechanism 95L and the right link mechanism 95R serving as the connection mechanisms, by pushing and pulling the rear connection shaft 83 of the expansion and contraction mechanism 70 as the movable body 93 moves, a pair of left and right X-shaped arms on the lower stage (left lower stage X-shaped arm 71L and right lower stage X-shaped arm 71R) and a pair of left and right X-shaped arms on the upper stage (left upper stage X-shaped arm 75L and right upper stage X-shaped arm 75R) are configured to expand and contract in the vertical direction.

[0040] Specifically, in the present embodiment, the left link mechanism 95L includes a first link member 951L whose front end is rotatably connected to the left side surface of the movable body 93, and a rear end that is rotatably connected to the rear connection shaft 83 of the expansion and contraction mechanism 70 (that is, a pair of left and right X-shaped arms 71L and 71R on the lower stage and a pair of left and right X-shaped arms 75L and 75R on the upper stage), and a second link member 953L whose front end is rotatably connected to the rear end of the first link member 951L via a shaft member 952L. Similarly, the right link mechanism 95R includes a first link member 951R whose front end is rotatably connected to the right side surface of the movable body 93, and a rear end that is rotatably connected to the rear connection shaft 83 of the expansion and contraction mechanism 70, and a second link member 953R whose front end is rotatably connected to the rear end of the first link member 951R via a shaft member 952R. Further, the first link member 951L of the left link mechanism 95L and the first link member 951R of the right link mechanism 95R are connected by a connection plate 954.

[0041] The left guide member 97L and the right guide member 97R are respectively arranged on both the left and right sides of the electric actuator 91 with the electric actuator 91 sandwiched therebetween on the rear side of the installation portion 37 provided one step lower than the base 30 inside the base 30. A guide hole 971L for guiding the movement of the shaft member 952L of the left link mechanism 95L as the movable body 93 moves is formed in the left guide member 97L, and a guide hole 971R for guiding the movement of the shaft member 952R of the right link mechanism 95R as the movable body 93 moves is formed in the right guide member 97R. The guide hole 971L of the left guide member 97L and the guide hole 971R of the right guide member 97R are formed in the same shape.

[0042] The shapes of the guide holes 971L of the left guide member 97L and the guide holes 971R of the right guide member 97R are determined as follows, for example. Here, the shape of the guide hole 971R of the right guide member 97R will be described with reference to FIG. 9, but the same applies to the shape of the guide hole 971L of the left guide member 97L.

[0043] First, when the loading platform 50 moves up and down between the lowest position and the highest position, it is assumed that the first connection part J1 between the movable body 93 and the front end part of the first link member 951R moves on the X axis, and the second connection part J2 between the second link member 953R and the rear connection shaft 83 moves on the Y axis (see FIG. 9).

[0044] Next, the relationship between the position (x, 0) of the first connection part J1 and the position (0, y) of the second connection part J2, that is, the relationship between x and y, is determined by physical laws (here, the principle of virtual work). The relationship between y and x (for example, dy / dx) may be a constant, linear, or non-linear. In this embodiment, the relationship between y and x (dy / dx) is set as a constant, so that, as will be described later, the output of the electric actuator 91 is substantially constant while the loading platform 50 is lifted from the lowest position to the highest position.

[0045] Next, based on the relationship between the position (x, 0) of the first connection part J1, the length L1 of the first link member 951R, the position (0, y) of the second connection part J2, and the length L2 of the second link member 953R, specifically, by inverse kinematics or the geometric relationship of the mechanism, the displacement angle θ1 (the angle with respect to the X axis) of the first link member 951R is obtained.

[0046] Then, based on the position (x, 0) of the first connecting portion J1, the length L1 of the first link member 951R, and the displacement angle θ1 of the first link member 951R, the position (x0, y0) of the center J3 of the shaft member 952R is obtained, and the shape of the guide hole 971R is determined by connecting the obtained positions (x0, y0) of the center J3 of the shaft member 952R. Here, there are two solutions for the displacement angle θ1 of the first link member 951R (the displacement angle θ1 can take two values). In the present embodiment, mainly to reduce the sizes of the guide holes 971L and 971R, the smaller one of the two solutions (two values) is adopted as the displacement angle θ1 of the first link member 951R. As a result, the guide holes 971L and 971R have the shapes shown in FIGS. 9, 10, etc.

[0047] Note that the guide hole 971R is formed with a curved shape so that the shaft member 952R can move smoothly. In the present embodiment, the guide hole 971R is curved in a substantially U shape (or substantially V shape) so that, as the movable body 93 moves in the direction of raising the loading platform 50, the shaft member 952R is moved obliquely downward rearward and then obliquely upward.

[0048] The control device 100 includes a power supply and a control circuit, and is installed adjacent to the electric motor 911 in an installation portion 37 provided inside the base 30 and one step lower than the base 30. An output signal of an encoder (rotation sensor) 914 is input to the control device 100.

[0049] The control device 100 controls the electric motor 911 of the electric actuator 91 based on an operation command input via an input unit (not shown). In the present embodiment, the operation command includes a raise command for raising the loading platform 50, a lower command for lowering the loading platform 50, and a stop command for stopping the raising and lowering of the loading platform 50. The stop command includes stopping the input of the raise command and / or stopping the input of the stop command. Then, when the raise command is input, the control device 100 rotationally drives the electric motor 911 in the first direction (hereinafter referred to as "forward rotation drive"), and when the lower command is input, the control device 100 rotationally drives the electric motor 911 in the second direction opposite to the first direction (hereinafter referred to as "reverse rotation drive"). Further, when the stop command is input, the control device 100 controls the electric motor 911 to hold the loading platform 50 at the raising and lowering position at that time.

[0050] Next, an example of the raising and lowering operation of the loading platform 50 in the transport cart 10 will be described with reference to FIGS. 12 to 14. Here, the case where no load is placed on the loading platform 50 will be described, but the same applies to the case where a load is placed on the loading platform 50.

[0051] FIG. 12 shows the state of the telescopic mechanism 70 and the drive device 90 when the loading platform 50 is at the lowest position, FIG. 13 shows the state of the telescopic mechanism 70 and the drive device 90 when the loading platform 50 is at the intermediate position, and FIG. 14 shows the state of the telescopic mechanism 70 and the drive device 90 when the loading platform 50 is at the uppermost position.

[0052] For example, when the operator inputs the raising command via the input unit while the loading platform 50 is in the lowest position, the control device 100 drives the electric motor 911 of the electric actuator 91 to rotate forward. Then, the movable body 93 moves backward, and the rear connecting shaft 83 of the telescopic mechanism 70 is pushed upward via the left link mechanism 95L (the first link member 951L, the shaft member 952L, and the second link member 953L) and the right link mechanism 95R (the first link member 951R, the shaft member 952R, and the second link member 953R). As a result, the pair of left and right X-shaped arms on the lower stage (the left lower X-shaped arm 71L and the right lower X-shaped arm 71R) and the pair of left and right X-shaped arms on the upper stage (the left upper X-shaped arm 75L and the right upper X-shaped arm 75R) extend upward, and the loading platform 50 rises. Then, when the loading platform 50 rises to the uppermost position, the control device 100 stops the forward rotation drive of the electric motor 911 of the electric actuator 91 and controls the electric motor 911 of the electric actuator 91 to hold the loading platform 50 at the uppermost position (Figure 12 → Figure 13 → Figure 14).

[0053] Also, for example, when the operator inputs the lowering command via the input unit while the loading platform 50 is in the uppermost position, the control device 100 drives the electric motor 911 of the electric actuator 91 to rotate in reverse. Then, the movable body 93 moves forward, and the rear connecting shaft 83 of the telescopic mechanism 70 is pulled downward via the left link mechanism 95L and the right link mechanism 95R. As a result, the pair of left and right X-shaped arms on the lower stage (the left lower X-shaped arm 71L and the right lower X-shaped arm 71R) and the pair of left and right X-shaped arms on the upper stage (the left upper X-shaped arm 75L and the right upper X-shaped arm 75R) contract downward, and the loading platform 50 descends. Then, when the loading platform 50 descends to the lowermost position, the control device 100 stops the reverse rotation drive of the electric motor 911 of the electric actuator 91 (Figure 14 → Figure 13 → Figure 12).

[0054] In addition, when the worker inputs the stop command via the input unit when the loading platform 50 has risen or fallen to the intermediate position, the control device 100 stops the forward or reverse rotation of the electric motor 911 of the electric actuator 91 and controls the electric motor 911 of the electric actuator 91 to hold the loading platform 50 at the current lifted or lowered position (intermediate position) (Figure 13).

[0055] In this embodiment, a non-excitation operated brake 912 is attached to the output shaft of the electric motor 911 of the electric actuator 91. Therefore, even if the supply of power to the electric actuator 91 (electric motor 911) is stopped, the loading platform 50 is held in the position at that time.

[0056] FIG. 15 is a diagram showing an example of the results of a comparison between the transport cart 10 according to the embodiment and a conventional transport cart of the same type, and shows the output of the electric actuator when the platform with cargo on it is raised from the lowest position to the highest position.

[0057] As shown by the dashed line in Fig. 15, in a conventional transport platform of the same type, the output of the electric actuator is maximum when the platform is raised from the lowest position, and then the output of the electric actuator decreases as the platform rises. In contrast, in the transport platform 10 according to the embodiment, as shown by the solid line in Fig. 15, the output of the electric actuator when raising the platform 50 from the lowest position is smaller than that of a conventional transport platform of the same type, and the output F of the electric actuator 91 is approximately constant while the platform 50 is raised from the lowest position to the highest position. Accordingly, the lifting speed of the platform 50 is also constant while the platform 50 is raised from the lowest position to the highest position.

[0058] As described above, the carrier cart 10 according to the embodiment is configured to move the loading platform 50 up and down by expanding and contracting a pair of left and right X-shaped arms on the lower and upper sides by a driving device 90. The driving device 90 includes an electric actuator 91, a movable body 93 that is driven by the electric actuator 91 to move, a pair of left and right link mechanisms (left link mechanism 95L and right link mechanism 95R), and a pair of left and right guide members (left guide member 97L and right guide member 97R).

[0059] The left link mechanism 95L (right link mechanism 95R) includes a first link member 951L (951R) whose front end is rotatably connected to the movable body 93, and a rear end that is rotatably connected to the rear connecting shaft 83 of the telescopic mechanism 70 (that is, a pair of left and right X-shaped arms on the lower and upper sides), and a front end that is rotatably connected to the rear end of the first link member 951L (951R) via a shaft member 952L (952R). A second link member 953L (953R). Further, a guide hole 971L (guide hole 971R) for guiding the movement of the shaft member 952L (shaft member 952R) accompanying the movement of the movable body 93 is formed in the left guide member 97L (right guide member 97R), and the guide hole 971L (971R) has a curved shape so as to smoothly move the shaft member 952L (952R).

[0060] Then, the driving device 90 moves the movable body 93 in the front-rear direction by the electric actuator 91, and the movement of the movable body 93 pushes and pulls the rear connecting shaft 83 of the telescopic mechanism 70 via the first link member 951L (951R) and the second link member 953L (953R), thereby expanding and contracting a pair of left and right X-shaped arms on the lower and upper sides in the vertical direction to move the loading platform 50 up and down. It is configured to

[0061] According to the transporter cart 10 of the embodiment, the output of the electric actuator 91 required to raise the platform 50 at the lowest position can be reduced compared to conventional transporter carts of the same type, and fluctuations in the output of the electric actuator 91 required in the process of raising the platform 50 are also suppressed (see FIG. 15). Therefore, it is possible to use a smaller electric actuator 91 (electric motor 911) than conventionally, and the cost of the transporter cart 10 can be reduced. Furthermore, fluctuations in the lifting and lowering speed of the platform 50 can also be suppressed.

[0062] In the above-described embodiment, the telescopic mechanism 70 is formed as a two-tiered X-shaped link mechanism in which a pair of left and right X-shaped arms are stacked one above the other. However, this is not limited to this. The telescopic mechanism 70 may be formed as a single-tiered X-shaped link mechanism made up of a pair of left and right X-shaped arms, or as a three or more tiered X-shaped link mechanism in which three or more pairs of left and right X-shaped arms are stacked one above the other.

[0063] Furthermore, in the above-described embodiment, the left guide member 97L is formed with a guide hole 971L that guides the movement of the shaft member 952L of the left link mechanism 95L in association with the movement of the movable body 93, and the right guide member 97R is formed with a guide hole 971R that guides the movement of the shaft member 952R of the right link mechanism 95R in association with the movement of the movable body 93. However, this is not limited to this. A guide groove may be formed in the left guide member 97L instead of the guide hole 971L, and / or a guide groove may be formed in the right guide member 97R instead of the guide hole 971R.

[0064] In the above-described embodiment, the guide holes 971L of the left guide member 97L and the guide holes 971R of the right guide member 97R are formed to be curved in a substantially U shape (or a substantially V shape) such that as the movable body 93 moves in the direction of raising the loading platform 50, the shaft members 952L and 952R move obliquely downward toward the rear and then obliquely upward. However, the present invention is not limited to this. The shape of the guide holes 971L (971R) varies depending on the length L1 of the first link members 951L and 951R and the length L2 of the second link members 953L and 953R. For example, as shown in FIG. 16 corresponding to FIG. 9, the guide holes 971L (971R) may be formed such that as the movable body 93 moves in the direction of raising the loading platform 50, the shaft members 952L and 952R move horizontally toward the rear and then obliquely upward.

[0065] However, when the front-rear direction space for installing the electric actuator 91 is the same, the above-described embodiment allows the first link members 951L, 952R and / or the second link members 953L, 953R to be made longer than the modified example shown in FIG. 16, and accordingly, the loading platform 50 can be raised higher. Conversely, when the height to which the loading platform 50 is raised is the same, the above-described embodiment requires a smaller front-rear direction space for installing the electric actuator 91 than the modified example shown in FIG. 16. Therefore, in the case where the front-rear direction space for installing the electric actuator 91 is limited, such as in a transport cart, it can be said that the above-described embodiment is more advantageous than the modified example shown in FIG. 16.

[0066] In the above-described embodiment, the electric actuator 91 is formed as a linear actuator that converts the rotational motion of an electric motor into linear motion by a linear motion mechanism (for example, a ball screw mechanism) and outputs the linear motion. However, the present invention is not limited to this. The electric actuator 91 may be configured to linearly move the movable body 93 in the front-rear direction.

[0067] In the above-described embodiment, the relationship between y and x (dy / dx) is a constant when determining the shape of the guide holes 971L and 971R. However, this is not limiting. As described above, the relationship between y and x (dy / dx) can be linear or nonlinear. Changing the relationship between y and x changes the shape of the guide holes 971L and 971R, and changing the shape of the guide holes 971L and 971R changes the output of the electric actuator 91 required in the process of lifting the platform 50 and the lifting speed of the platform 50. In other words, the lifting characteristics of the platform 50 can be changed by changing the shape of the guide holes 971L and 971R. Therefore, the transporter platform 10 according to this embodiment has the advantage of being able to flexibly meet requirements regarding the lifting characteristics of the platform 50.

[0068] 17, the transport cart 10 may further include a position detection unit 110 capable of detecting the vertical position of the upper surface of the loading platform 50 and the vertical position of the upper surface of a load placed on the loading platform 50. Although not particularly limited, the position detection unit 110 may include, for example, a TOF distance measurement image sensor whose measurement area is a predetermined range on the upper surface of the loading platform 50, and is arranged facing the loading platform 50 at a predetermined position above the handle 40 using a holder 120 attached to the handle 40. The holder 120 may be formed in a roughly gate-like shape (roughly an inverted U-shape) like the handle 40, and may be configured to hold the position detection unit 110 via a bracket or the like (not shown).

[0069] The position detection unit 110 is capable of detecting the vertical position of the top surface of the loading platform 50 when no luggage is placed on the loading platform 50, and is capable of detecting the vertical position of the top surface of the luggage placed on the loading platform 50 when luggage is placed on the loading platform 50. The position detected by the position detection unit 110 is output to the control device 100.

[0070] The transport cart 10 shown in FIG. 17 is capable of the following operations in addition to raising and lowering the platform 50 and holding it at a predetermined raised or lowered position.

[0071] For example, when placing a load on the loading platform 50, the worker inputs the lift command via the input unit to lift the loading platform 50, which has no load placed on it, from the lowest position to a predetermined lift position, and then inputs the stop command via the input unit. As a result, the loading platform 50 is held at the predetermined lift position, and the worker starts placing the load on the loading platform 50, which is held at the predetermined lift position.

[0072] When the stop command is input (or when the loading platform 50 is held at the predetermined position), the control device 100 stores the position detected by the position detection unit 110 at that time as a reference position. Then, until the lifted / lowered position at which the loading platform 50 is held is changed, the control device 100 controls the electric motor 911 of the electric actuator 91 so that the position detected by the position detection unit 110 coincides with the reference position.

[0073] In this case, when a load is placed on the loading platform 50, the position detected by the position detection unit 110 will be above the reference position. Therefore, the control device 100 drives the electric motor 911 in the reverse direction to lower the loading platform 50 so that the position detected by the position detection unit 110 becomes the reference position. Thereafter, when the transport vehicle 10 moves to the destination of the load and the load placed on the loading platform 50 is removed, the position detected by the position detection unit 110 will be below the reference position. Therefore, the control device 100 drives the electric motor 911 in the forward direction to raise the loading platform 50 so that the position detected by the position detection unit 110 becomes the reference position.

[0074] By doing so, the vertical position of the upper surface of the loading platform 50 on which no load is placed and the vertical position of the upper surface of the load when the load is placed on the loading platform 50, that is, the position where the operator places the load and the position where the operator takes out the load are maintained substantially constant. That is, when the operator places a plurality of loads on the loading platform 50 in multiple stages, the placement operation of each load can be performed at the same height position, and when taking out the loads placed on the loading platform 50 in multiple stages, the taking-out operation of each load can be performed from the same height position. Therefore, the burden on the operator can be significantly reduced.

[0075] As described above, the embodiments and modified examples of the present invention have been described. However, the present invention is not limited to the above-described embodiments and modified examples, and it goes without saying that further modifications and changes are possible based on the technical idea of the present invention.

Explanation of Reference Numerals

[0076] 10... transport cart, 30... base, 40... handle, 50... loading platform, 70... telescopic mechanism, 71L... lower left X-shaped arm, 71R... lower right X-shaped arm, 72L, 72R... lower inner arms, 74L, 74R... lower outer arms, 75L... upper left X-shaped arm, 75R... upper right X-shaped arm, 76L, 76R... upper inner arms, 78L, 78R... upper outer arms, 81... lower connecting shaft, 82... upper connecting shaft, 83... rear connecting shaft, 84... front connecting shaft, 85... lower moving shaft, 86... upper moving shaft, 90... drive device, 91... electric actuator, 93... movable body, 94... linear slider, 95L... left link mechanism, 95R... right link mechanism, 97L... left guide member, 97R... right guide member, 100... control device, 110... position detection unit (position detection section), 911... electric motor, 913... reduction mechanism, 915A... linear shaft (lead screw shaft), 915B... linear nut, 951L, 951R... first link members, 952L, 952R... shaft members, 953L, 953R... second link members, 971L, 971R... guide holes (guide sections)

Claims

1. A base with wheels attached to the lower part, a loading platform arranged above the base, a pair of first left X-shaped arms and first right X-shaped arms provided between the base and the loading platform and capable of expanding and contracting in the vertical direction, and a driving device for expanding and contracting the first left X-shaped arms and the first right X-shaped arms to raise and lower the loading platform, Each of the first left X-shaped arm and the first right X-shaped arm has two arms that intersect in an X shape in a side view and are combined so as to be relatively rotatable with respect to each other, One end of one of the two arms of the first left X-shaped arm is rotatably attached near the left end of a connecting shaft extending in the left-right direction, and one end of the arm corresponding to the one arm of the first left X-shaped arm among the two arms of the first right X-shaped arm is rotatably attached near the right end of the connecting shaft, The driving device includes an electric actuator, a movable body driven by the electric actuator to move in the front-rear direction, a first link member having one end rotatably connected to the movable body, a second link member having one end rotatably connected to the connecting shaft and the other end rotatably connected to the other end of the first link member via a shaft member, and a guide member having a guide hole or a guide groove formed to guide the movement of the shaft member accompanying the movement of the movable body. The first left X-shaped arm and the first right X-shaped arm are configured to expand and contract in the vertical direction via the first link member and the second link member by the movement of the movable body, The guide hole or the guide groove is formed to be curved in a substantially U shape so that the shaft member is moved obliquely downward and then obliquely upward as the movable body moves in the direction of raising the loading platform, A transport trolley.

2. Further including a pair of second left X-shaped arms and second right X-shaped arms provided between the pair of first left X-shaped arms and first right X-shaped arms and the loading platform and capable of expanding and contracting in the vertical direction, Each of the first left X-shaped arm and the first right X-shaped arm has a first inner arm and a first outer arm as the two arms, Each of the second left X-shaped arm and the second right X-shaped arm has a second inner arm and a second outer arm that intersect in an X shape in a side view and are combined so as to be relatively rotatable with respect to each other, One end of the first inner arm of the first left X-shaped arm and one end of the second outer arm of the second left X-shaped arm are rotatably attached near the left end of the connecting shaft, and one end of the first inner arm of the first right X-shaped arm and one end of the second outer arm of the second right X-shaped arm are rotatably attached near the right end of the connecting shaft. The drive device is configured to expand and contract the first left X-shaped arm, the first right X-shaped arm, the second left X-shaped arm, and the second right X-shaped arm in the vertical direction through the first link member and the second link member by the movement of the movable body. The carrier truck according to claim 1.

3. The carrier truck according to claim 1 or 2, further comprising a control device that controls the electric actuator based on an operation command of the loading platform including a raising command for raising the loading platform and a lowering command for lowering the loading platform.

4. The electric actuator includes an electric motor, a linear motion shaft that is rotationally driven by the electric motor via a speed reduction mechanism, and a linear motion nut that moves in the axial direction of the linear motion shaft as the linear motion shaft rotates. The movable body is provided integrally with the linear motion nut. When raising the loading platform, the control device drives the electric motor in forward rotation, and when lowering the loading platform, the control device drives the electric motor in reverse rotation. The carrier truck according to claim 3.

5. The carrier truck has a position detection unit that detects the vertical position of the upper surface of the loading platform when no load is placed on the loading platform, and can detect the vertical position of the upper surface of the load placed on the loading platform when a load is placed on the loading platform. The control device uses the position detected by the position detection unit as a reference position when the loading platform is held at a predetermined lifting position, and can control the electric actuator so that the position detected by the position detection unit matches the reference position until the lifting position at which the loading platform is held is changed. The carrier truck according to claim 3 or 4.

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