Lifting system

Abstract

To prevent a lifting stage moving up and down along a structure from tilting beyond an allowable range during a lifting movement.SOLUTION: A lifting system includes a lifting stage that moves up and down along a structure, a first lifting device and a second lifting device that move the lifting stage up and down, and a control device that controls vertical movements of the first lifting device and the second lifting device. The control device determines whether a height difference between the first lifting device and the second lifting device exceeds a first threshold value. When the height difference exceeds the first threshold value, the control device determines whether the height difference exceeds a second threshold value greater than the first threshold value. If the height difference does not exceed the second threshold value, the control device performs a first control on at least one of the first lifting device and the second lifting device. If the height difference exceeds the second threshold value, the control device performs a second control different from the first control on at least one of the first lifting device and the second lifting device.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a lifting system, and more particularly to a lifting system in which a plurality of lifting devices work together to move a lifting stage up and down. [Background technology]

[0002] In the assembly, maintenance, or dismantling of large structures such as buildings and condominiums, a lifting system equipped with a lifting stage that moves up and down along the structure is used (Patent Document 1). In the lifting system, the lifting stage is supported by multiple lifting devices installed below it and moves up and down as the lifting devices move up and down. In order for workers to work safely on the lifting stage and for the equipment installed on the lifting stage to operate normally, it is necessary to keep the tilt of the lifting stage within a certain range. If there is variation in the amount of movement of the multiple lifting devices, the lifting stage will tilt after lifting. To limit this tilt, a technology has been used that installs a movement amount sensor on each lifting device to reduce the variation in the amount of movement of the lifting devices. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 60-43572 Summary of the Invention [Problem to be solved by the invention]

[0004] However, simply providing a movement amount sensor on each lifting device makes it difficult to keep the tilt of the lifting stage within a certain range. In particular, in large structures, if the size of the lifting stage is large and there is an error in the amount of movement between the lifting devices, even a slight difference in the amount of movement of the lifting devices can cause the lifting stage to tilt beyond the allowable range.

[0005] One embodiment of the present invention has been made in consideration of the above-mentioned problems, and one of its objectives is to prevent a lifting stage that moves up and down along a structure from tilting beyond an allowable range during its lifting and moving up and down. [Means for solving the problem]

[0006] An elevator system according to one embodiment of the present invention comprises an elevator stage that moves up and down along a structure, a first elevator device that moves the elevator stage up and down, a second elevator device that moves the elevator stage up and down, and a control device that controls the up and down movements of the first elevator device and the second elevator device, wherein the control device determines whether the difference in elevation between the first elevator device and the second elevator device exceeds a first threshold, and if the difference in elevation exceeds the first threshold, determines whether the difference in elevation exceeds a second threshold that is greater than the first threshold, and if the difference in elevation does not exceed the second threshold, performs a first control on at least one of the first elevator device and the second elevator device, and if the difference in elevation exceeds the second threshold, performs a second control different from the first control on at least one of the first elevator device and the second elevator device.

[0007] The first control may be a control for changing an amount of vertical movement of at least one of the first lifting device and the second lifting device.

[0008] The second control may be a control to stop the up and down movement of each of the first lifting device and the second lifting device, and to align the first lifting device and the second lifting device to the same height.

[0009] The control device may further include a level sensor provided on the first lifting device and the second lifting device, capable of detecting the positional relationship between the first lifting device and the second lifting device in the vertical direction, and the control device may calculate the height difference based on a signal from the level sensor.

[0010] The level sensor may include a first water level gauge attached to the first lifting device and a second water level gauge attached to the second lifting device, and the first water level gauge and the second water level gauge are configured so that the liquids inside them can move relative to each other, and the control device may calculate the difference in elevation based on signals from the first water level gauge and the second water level gauge.

[0011] The structure may be a building.

[0012] The lift stage may surround the periphery of the building.

[0013] The control device may move up and down together with the lift stage. [Effects of the Invention]

[0014] According to the lifting system according to one embodiment of the present invention, it is possible to prevent the lifting stage, which moves up and down along the structure, from tilting beyond an allowable range during the lifting movement. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing the appearance of a lifting system according to an embodiment of the present invention; [Figure 2] 1 is a perspective view showing the appearance of a lifting system according to an embodiment of the present invention; [Figure 3] 1 is a top view showing the appearance of a lifting system according to an embodiment of the present invention; [Figure 4] 1A and 1B are diagrams illustrating the structure and operation of a lifting device according to an embodiment of the present invention. [Figure 5] 10A and 10B are diagrams illustrating a method for detecting tilt of a lift stage according to an embodiment of the present invention. [Figure 6] 10A and 10B are diagrams illustrating a method for detecting tilt of a lift stage according to an embodiment of the present invention. [Figure 7] 4 is a flowchart showing the operation of the lifting system according to the embodiment of the present invention. [Figure 8]4 is a flowchart showing the operation of the lifting system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a lifting system according to one embodiment of the present invention will be described with reference to the drawings. However, the lifting system according to one embodiment of the present invention can be implemented in many different ways, and should not be construed as being limited to the description of the example shown below. In the drawings referred to in this embodiment, identical parts or parts having similar functions are given the same reference numerals, and repeated explanations thereof will be omitted.

[0017] In each embodiment of the present invention, the direction in which the lifting system moves against gravity is referred to as "upward," and the opposite direction is referred to as "downward." In the following description, for example, the expression "a second member above a first member" merely describes the vertical positional relationship between the first member and the second member as described above, and other members may be disposed between the first member and the second member. Furthermore, when the expression "a second member above a first member" is used, the first member and the second member may not overlap in a top view. On the other hand, when the expression "a second member vertically above a first member" is used, it means that the first member and the second member overlap in a top view.

[0018] In this specification, unless otherwise specified, expressions such as "α includes A, B, or C," "α includes any one of A, B, and C," and "α includes one selected from the group consisting of A, B, and C" do not exclude cases where α includes multiple combinations of A to C. Furthermore, these expressions do not exclude cases where α includes other elements.

[0019] [1. Overall structure] The overall configuration of a lifting system 10 according to this embodiment will be described with reference to Figures 1 to 3. Figures 1 and 2 are both perspective views showing the appearance of a lifting system according to one embodiment of the present invention. Figure 3 is a top view showing the appearance of a lifting system according to one embodiment of the present invention.

[0020] As shown in FIG. 1 , the lifting system 10 surrounds the periphery of the structure 20 and moves up and down (up and down) along the structure 20. The structure 20 is, for example, a building such as a detached house, an apartment, a condominium, a bridge pier, or a commercial building. In this embodiment, the structure 20 is a rectangular structure (tetrahedral prism) when viewed from above, but the structure 20 may be another polygonal structure (polyhedral prism), or may be a circular or elliptical structure (cylindrical body). When viewed from above, the shape of the lifting system 10 follows the outer shape of the structure 20. That is, in this embodiment, the shape of the lifting system 10 when viewed from above is rectangular, but it may be a polygon other than a rectangle, or may be a circle or an ellipse depending on the shape of the outer periphery of the structure.

[0021] As shown in Fig. 2, the lifting system 10 includes a lifting stage 100, lifting devices 210 and 220, a rod 230, a rod stay 240, and a control device 300. In the following description, when there is no need to distinguish between the lifting devices 210 and 220, they will simply be referred to as the lifting device 200. For the sake of convenience, the structure 20 is omitted from Fig. 2.

[0022] The lifting stage 100 moves up and down along the structure 20. The shape of the lifting stage 100 is a shape that follows the outer periphery of the structure 20. In this embodiment, the lifting stage 100 is strip-shaped and rectangular, and surrounds the periphery of the structure 20. The lifting stage 100 provides a foothold for workers or various equipment. Although not shown, the lifting stage 100 has a main frame, to which plate-like members or grating members that function as footholds are fixed. Although not shown, fences or handrails are provided on the inside (the side closer to the structure 20) and outside (the side farther from the structure 20) of the lifting stage 100. Note that, in this embodiment, a configuration in which the lifting stage 100 surrounds the outer periphery of the structure 20 is illustrated as an example, but the present invention is not limited to this configuration. For example, the lifting stage 100 may be provided inside the structure 20.

[0023] In the present embodiment, a configuration in which the lifting stage 100 continuously surrounds the entire periphery of the structure 20 has been exemplified, but the configuration is not limited to this. For example, the lifting stage 100 may be provided along at least a portion of the outer periphery of the structure 20.

[0024] The lifting device 200 supports the lifting stage 100 and moves it up and down. The lifting device 200 may be provided above the lifting stage 100, below the lifting stage 100, or inside the lifting stage 100. The lifting device 200 is fixed to the main frame of the lifting stage 100. While FIG. 2 illustrates a configuration in which only the lifting devices 210 and 220 are provided along one side of the lifting stage 100, other lifting devices 200 may be provided along other sides. The lifting device 200 moves up and down along a rod 230. The detailed configuration and operation of the lifting device 200 will be described later. The lifting device 210 may be referred to as a "first lifting device," and the lifting device 220 may be referred to as a "second lifting device."

[0025] The rod 230 extends in the vertical direction along the structure 20. The rod 230 is fixed to the structure 20 by a rod stay 240. The rod stay 240 extends from the rod 230 toward the structure 20 and is detachably fixed to the structure 20. Since the rod 230 is fixed by the rod stay 240, the horizontal position of the rod 230 is fixed, and therefore, horizontal displacement of the lifting stage 100 can be suppressed.

[0026] Although the details will be described later, the rod 230 is provided so as to penetrate the inside of the lifting device 200, and therefore, when the lifting device 200 rises, the rod stay 240 is fixed (attached) to the rod 230 and the structure 20 after the lifting device 200 has passed. On the other hand, when the lifting device 200 descends, the rod stay 240 is detached from the rod 230 and the structure 20 immediately before the lifting device 200 passes.

[0027] The control device 300 controls the up and down movement of the lifting devices 210 and 220 so that the tilt of the lifting stage 100 falls within a predetermined range. As will be described in detail later, the lifting device 200 is provided with a level sensor 400 (see FIG. 5 ), and the control device 300 controls the up and down movement of the lifting devices 210 and 220 based on a signal from the level sensor 400. Specifically, when the positions of the lifting devices 210 and 220 in the vertical direction are different, the control device 300 causes the lifting devices 210 and 220 to perform different operations. As will be described in detail later, when the level sensor 400 indicates that the lifting device 210 is lower than the lifting device 220, the control device 300 restricts the upward movement of the lifting device 220. The control device 300 is provided above the lifting stage 100 and moves up and down together with the lifting stage 100.

[0028] As shown in FIG. 3 , the lifting devices 200 are provided along each side of the rectangular lifting stage 100. In the present embodiment, a configuration in which two lifting devices 200 are provided on each side has been exemplified, but this configuration is not limiting. One lifting device 200 may be provided on each side, or three or more may be provided on each side. Furthermore, in the present embodiment, a configuration in which the same number of lifting devices 200 are provided on each side has been exemplified, but this configuration is not limiting. The number of lifting devices 200 provided on at least some of the sides of the lifting stage 100 may be different from the number of lifting devices 200 provided on the other sides. For example, when the shape of the lifting stage 100 is rectangular in top view, the number of lifting devices 200 provided on the long sides may be greater than the number of lifting devices 200 provided on the short sides.

[0029] The control device 300 may control the up and down movement of all of the lifting devices 200 provided on the lifting stage 100 so that the inclination of the lifting stage 100 falls within a predetermined range, or may control the up and down movement of only some of the lifting devices 200 provided on the lifting stage 100.

[0030] 2. Configuration and Operation of the Lifting Device 200 4 is a diagram showing the structure and operation of an elevator device according to one embodiment of the present invention. As shown in FIG. 4, an elevator device 200 includes a housing 201, an actuator 202, and grippers 203 and 204.

[0031] The housing 201 supports the lifting stage 100. The actuator 202 and the grippers 203 and 204 are disposed inside the housing 201. Openings 205 and 206 are provided at the top and bottom of the housing 201. The lifting device 200 is disposed so that the rod 230 passes through the openings 205 and 206.

[0032] One end of the actuator 202 is connected to the gripper 203, and the other end is connected to the gripper 204. The grippers 203 and 204 are arranged so as to be movable within the housing 201 along the rod 230 as the actuator 202 expands and contracts. As the actuator 202, an electric actuator, a hydraulic actuator, a pneumatic actuator, or an electrorheological fluid actuator is used. In this embodiment, a hydraulic cylinder is used as the actuator 202.

[0033] The gripping units 203 and 204 fix the positions of the gripping units 203 and 204 relative to the rod 230 by gripping the rod 230, and make the positions of the gripping units 203 and 204 relative to the rod 230 movable by releasing the rod 230. The gripping units 204 also support the housing 201. Note that, although the present embodiment has been described with reference to a configuration in which the gripping units 204 support the upper part of the housing 201 from below, the present invention is not limited to this configuration. For example, the gripping units 204 may support the sides of the housing 201 from the sides. Alternatively, the gripping units 204 may support the housing 201 via another member.

[0034] As shown in FIG. 4A, from a state in which actuator 202 is contracted, gripper 203 grips rod 230, and gripper 204 releases the rod, actuator 202 extends, causing gripper 204 to push housing 201 upward, and lift stage 100 to be pushed upward as shown in FIG. 4B. A single lifting operation is performed by transitioning from the state shown in FIG. 4A to the state shown in FIG. 4B. The amount of lift achieved by a single lifting operation is sometimes referred to as "one stroke." From the state shown in FIG. 4B, gripper 204 grips rod 230, gripper 203 releases rod 230, and actuator 202 contracts, causing gripper 203 to move upward as shown in FIG. 4C. From the state shown in FIG. 4C, gripper 203 grips rod 230, and gripper 204 releases rod 230, returning to the state shown in FIG. 4A. As described above, the lift stage 100 rises by repeating the operations (A) to (C). When the lift stage 100 descends, it operates in the reverse order of (C) → (B) → (A). One lowering operation is performed by transitioning from the state shown in (B) to the state shown in (A). The amount of descent in one lowering operation is sometimes referred to as "one stroke."

[0035] The actuator 202 is provided with a movement amount detection sensor that detects the amount of movement of the piston rod relative to the cylinder tube. The movement amount detection sensor makes it possible to calculate the amount by which the actuator 202 has expanded or contracted.

[0036] [3. Configuration of the level sensor 400] 5 and 6 are diagrams illustrating a method for detecting the tilt of a lifting stage according to one embodiment of the present invention. As shown in FIG. 5, the lifting devices 210 and 220 are provided with level sensors 410 and 420, respectively. In the following description, when there is no need to distinguish between the level sensors 410 and 420, they will simply be referred to as the level sensor 400. The level sensor 400 is a sensor capable of detecting the positional relationship between the lifting devices 210 and 220 in the vertical direction. The level sensor 410 is provided on the lifting stage 100 vertically above the lifting device 210. The level sensor 420 is provided on the lifting stage 100 vertically above the lifting device 220. However, the position of the level sensor 400 is not limited to the above example.

[0037] The level sensor 400 may be a sensor capable of detecting the relative positional relationship between the lifting devices 210, 220 in the vertical direction, or a sensor capable of detecting their absolute positions. The former sensor may be, for example, a water level gauge or a magnetostrictive sensor. The latter sensor may be, for example, an optical sensor or an encoder. The signal detected by the level sensor 400 is transmitted to the control device 300. In this embodiment, a configuration in which a water level gauge is used as the level sensor 400 will be described.

[0038] When a water level gauge is used as the level sensor 400, the level sensors 410, 420 each include a liquid holding portion 411, 421 that holds liquid therein. In this case, the level sensor 410 can be referred to as the "first water level gauge," and the level sensor 420 can be referred to as the "second water level gauge." The liquid holding portions 411, 421 are provided with water level sensors 412, 422. The water level sensors 412, 422 detect the height of the water surface 413, 423 of the liquid held in the liquid holding portions 411, 421.

[0039] The water level sensors 412, 422 may be non-contact sensors or contact sensors. As the non-contact sensors, radio wave sensors or ultrasonic sensors may be used. As the contact sensors, float sensors, guide lobe sensors, pressure sensors, capacitance sensors, or differential pressure sensors may be used. When contact sensors are used as the water level sensors 412, 422, the positions of the sensors are determined according to the characteristics of the sensors.

[0040] The level sensor 410 (first water level indicator) and the level sensor 420 (second water level indicator) are configured to allow the liquid therein to move relative to each other. Therefore, as shown in FIG. 6, when the position of the level sensor 410 is lower than the position of the level sensor 420 in the vertical direction, the liquid flows from the liquid holding portion 421 to the liquid holding portion 411. As a result, the water surface 413 becomes higher than the water surface 423. Therefore, the height difference between the level sensors 410 and 420 can be calculated based on the signals output from the water level sensors 412 and 422. In other words, the control device 300 controls the up and down movement of the lifting devices 210 and 220 based on the signals from the level sensor 410 (first water level indicator) and the level sensor 420 (second water level indicator).

[0041] 4. Control Method of the Control Device 300 The control method of the control device 300 will be described with reference to Figures 7 and 8. Figure 7 is a flowchart showing the operation of the lifting system according to one embodiment of the present invention. Figure 8 is a flowchart showing the operation of the lifting system according to one embodiment of the present invention.

[0042] 7 is started when an operator instructs the control device 300 to perform a lifting operation of the lifting stage 100. The following operations are realized by cooperation between the arithmetic processing device and storage device provided in the control device 300. Specifically, the arithmetic processing device reads out a program stored in the storage device and performs processing based on the program, thereby realizing the following operations.

[0043] In this embodiment, a configuration for detecting the height difference between the lifting devices 210 and 220 will be described as an example of a plurality of lifting devices 200. However, when three or more lifting devices 200 are connected to the lifting stage 100 as shown in FIG. 3, the height difference between the highest and lowest lifting devices 200 among all of these lifting devices 200 may be detected, or the height difference between the highest and lowest lifting devices 200 among some of the lifting devices 200 may be detected.

[0044] First, the control device 300 creates a correction table for the lifting devices based on the setting values ​​(target values ​​for the movement amounts) input by the worker (step S701). Due to variations in the operation of each of the lifting devices 210, 220, the actual movement amounts of the lifting devices 210, 220 may differ from the setting values. The correction table is a table for correcting the movement amounts of the lifting devices 210, 220 relative to the target values ​​so that the actual movement amounts of the lifting devices 210, 220 become equal to the target values. The method for creating the correction table will be described in detail later.

[0045] When the creation of the correction table is completed in S701, the control device 300 sets the corrected movement amounts for the lifting devices 210, 220 based on the correction table (step S702). Following S702, the control device 300 starts the lifting and lowering movement of the lifting devices 210, 220 based on the corrected movement amounts (step S703).

[0046] When the movement of the lifting devices 210, 220 starts, the control device 300 detects the difference in elevation between the lifting devices 210, 220 at a predetermined timing, compares the difference in elevation with a first threshold value indicating a first allowable range of tilt of the lifting stage 100, and determines whether the difference in elevation exceeds the first threshold value (step S704). Specifically, the control device 300 compares the difference in elevation between the position of the lifting device 210 and the position of the lifting device 220 in the vertical direction with the first threshold value. Note that the predetermined timing may be at regular intervals, or may be every one or N extension or contraction operations (one stroke or N strokes) of the actuator 202 (N is a natural number of 2 or greater).

[0047] If the height difference exceeds the first threshold in S704 ("Y" in S704), the control device 300 compares the height difference with a second threshold that indicates a second allowable range of tilt of the lifting stage 100, and determines whether the height difference exceeds the second threshold (step S711). On the other hand, if the height difference does not exceed the first threshold in S704 ("N" in S704), the control device 300 continues the movement of the lifting devices 210, 220 (step S705).

[0048] If the elevation difference does not exceed the second threshold in S711 ("N" in S711), the control device 300 updates the correction table (step S712). Since the control device 300 controls the up and down movement of the lifting devices 210 and 220 based on the correction table, ideally, no elevation difference occurs between the lifting devices 210 and 220. However, due to factors such as the loads acting on the lifting devices 210 and 220, the correction made by the correction table may not reflect the actual movement. In other words, a discrepancy may occur in the amount of movement of the lifting devices 210 and 220 after correction by the correction table. To correct this discrepancy, the correction table is updated in S712. Specifically, the control device 300 corrects the amount of correction in the correction table based on the elevation difference between the lifting devices 210 and 220 detected in S704.

[0049] Following S712, the control device 300 calculates the difference between the current position (current movement amount) and the target value, and sets it as the remaining movement amount (step S713). Following S713, the control device 300 continues the up / down movement of the lifting devices 210, 220 based on the remaining movement amount (step S714).

[0050] Here, the second threshold is a value different from the first threshold. In this embodiment, the second threshold is greater than the first threshold. When the movement amounts of the lifting devices 210 and 220 are different, the greater the total movement amount, the greater the difference in height between the lifting devices 210 and 220, resulting in a greater inclination of the lifting stage 100. When the inclination of the lifting stage 100 reaches its allowable limit, it is necessary to stop the current up and down movement of the lifting devices 210 and 220 and perform a corrective operation to correct the inclination of the lifting stage 100. The second threshold is a criterion for determining whether or not to perform this corrective operation. On the other hand, the first threshold is a criterion for determining that the current up and down movement is not enough to stop the current up and down movement and correct the inclination of the lifting stage 100, but that if the up and down movement continues, a corrective operation will eventually be necessary. Note that the second threshold may be smaller than the first threshold.

[0051] In other words, steps S712 to S714 are steps for preventing the control device 300 from stopping the up and down movement and executing a corrective operation. In steps S712 to S714, the control device 300 adjusts the amount of movement of the lifting devices 210 and 220 without stopping the current up and down movement, thereby preventing the tilt of the lifting stage 100 from becoming larger or reducing the tilt (bringing the lifting stage 100 closer to horizontal).

[0052] If the height difference exceeds the second threshold in S711 ("Y" in S711), the control device 300 performs control to move the lifting devices 210, 220 to a horizontal position using the lifting device 210 or the lifting device 220 as a reference (step S721). If three or more lifting devices 200 are connected to the lifting stage 100, in S721, control is performed to move each lifting device 200 to a horizontal position using one lifting device 200 as a reference. In this case, the lifting device 200 that serves as the reference in S721 may be the lifting device 200 located at the highest position among the multiple lifting devices 200, may be the lifting device 200 located at the lowest position, or may be the lifting device 200 at a height corresponding to the median when the multiple lifting devices 200 are arranged in order of height in the vertical direction.

[0053] In the above-described control for moving to the horizontal position, the reference lifting device 200 may be any lifting device 200 selected by the worker. In this case, a step for prompting the worker to select the reference lifting device 200 is provided between S711 and S721. Specifically, an interface for prompting the worker to select the reference lifting device 200 is displayed on a display screen provided in the control device 300 or a display screen provided in a communication terminal capable of communicating with the control device 300. The control device 300 raises and lowers the lifting devices 200 other than the reference lifting device 200 to the same height as the reference lifting device 200.

[0054] After performing the control of S721, the control device 300 updates the correction table in the same manner as in S712 (step S722). Following S722, the control device 300 calculates the difference between the current position (current movement amount) and the target value, and sets it as the remaining movement amount (step S723). Following S723, the control device 300 starts the lifting movement of the lifting devices 210, 220 based on the remaining movement amount (step S724).

[0055] Here, the control related to S712 to S714 may be referred to as "first control." The control related to S721 to S724 may be referred to as "second control." In this case, the control device 300 performs the first control when the difference in elevation between the lifting devices 210 and 220 exceeds the first threshold but does not exceed the second threshold, and performs the second control, which is different from the first control, when the difference in elevation exceeds both the first threshold and the second threshold. In the first control and the second control, the control device 300 may perform the above control on one of the lifting devices 210 and 220, or may perform the above control on both the lifting devices 210 and 220. As described above, the first control is control that changes the amount of vertical movement of the lifting devices 210 and 220. The second control is control that stops the vertical movement of the lifting devices 210 and 220 and aligns the lifting devices 210 and 220 to the same height.

[0056] When the operations of S705, S714, and S724 are started, the control device 300 determines at a predetermined timing whether the movement amount of the lifting devices 210, 220 has reached the target value (step S706). If it is determined at S706 that the movement amount has not reached the target value ("N" at S706), the control device 300 continues the movement of the lifting devices 210, 220 (S703) and performs the determination of S704 at a predetermined timing. On the other hand, if it is determined at S705 that the movement amount has reached the target value ("Y" at S705), the flow shown in FIG. 7 ends.

[0057] The flowchart shown in Fig. 8 is a flowchart related to the creation of the correction table in S701 of Fig. 7. As shown in Fig. 8, when creation of the correction table starts, the control device 300 moves the lifting devices 210, 220 by a first set value (step S801). Following S801, the control device 300 reads the movement amount detection sensors and level sensors 410, 420 of the lifting devices 210, 220 after movement (step S802). The movement amount detection sensors are sensors that detect the movement amount of the piston rod relative to the cylinder tube, as described above.

[0058] In S802, if there is operational variation in the lifting devices 210, 220, even though the outputs of the movement amount detection sensors of both are the same, a difference in height occurs between the lifting devices 210, 220 from the outputs of the level sensors 410, 420. After S802, the control device 300 moves the positions of the lifting devices 210, 220 to their initial positions (the same positions as before S801) (step S803).

[0059] Following S803, the control device 300 moves the lifting devices 210, 220 using a second set value different from the first set value (step S804). Following S804, the control device 300 reads the movement amount detection sensors and level sensors 410, 420 of the lifting devices 210, 220 after the movement (step S805). After S805, the control device 300 moves the positions of the lifting devices 210, 220 to their initial positions (the same positions as before S804) (step S806).

[0060] If the movement amount associated with the second set value is greater than the movement amount associated with the first set value, the elevation difference between the lifting devices 210 and 220 obtained in S805 is greater than the elevation difference obtained in S802. In each of S802 and S805, a linear slope (deviation of the actual movement amount from the predetermined set value) is calculated for each of the lifting devices 210 and 220 based on the elevation difference between the lifting devices 210 and 220 obtained from the output of the level sensors 410 and 420 and the difference in the movement amount between the first set value and the second set value obtained from the output of the movement amount detection sensor. A correction table is created based on this linear slope (step S807). The correction table is created in S701 of FIG. 7 through the above operation. Note that the method for creating the correction table according to this embodiment is merely an example and is not limited to the above method.

[0061] The lifting system 10 according to this embodiment can prevent the lifting stage 100 from tilting beyond an allowable range during lifting operation.

[0062] The above-described embodiments of the present invention may be combined as appropriate as long as they are not mutually inconsistent. Furthermore, even if a person skilled in the art appropriately adds or deletes components or modifies the design based on each embodiment, or adds or omits steps or modifies conditions, such combinations are included in the scope of the present invention as long as they include the gist of the present invention.

[0063] Even if there are other effects and advantages different from those brought about by the above-mentioned embodiments, those that are clear from the description in this specification or that can be easily predicted by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0064] 10: Lifting system, 20: Structure, 100: Lifting stage, 200, 210, 220: Lifting device, 201: Housing, 202: Actuator, 203, 204: Gripper, 205, 206: Opening, 230: Rod, 240: Rod stay, 300: Control device, 400, 410, 420: Level sensor, 411, 421: Liquid holder, 412, 422: Water level sensor, 413, 423: Water surface

Claims

1. a lifting stage that moves up and down along the structure; a first lifting device that moves the lifting stage up and down; a second lifting device that moves the lifting stage up and down; a control device that controls the up and down movements of the first lifting device and the second lifting device, The control device determining whether a height difference between the first lifting device and the second lifting device exceeds a first threshold value; If the elevation difference exceeds the first threshold, it is determined whether the elevation difference exceeds a second threshold that is greater than the first threshold; When the height difference does not exceed the second threshold value, a first control is performed on at least one of the first lifting device and the second lifting device; When the elevation difference exceeds the second threshold, a second control different from the first control is performed on at least one of the first lifting device and the second lifting device.

2. The lifting system according to claim 1 , wherein the first control is a control for changing an amount of vertical movement of at least one of the first lifting device and the second lifting device.

3. The lifting system according to claim 2 , wherein the second control is a control for stopping the up and down movement of each of the first lifting device and the second lifting device and aligning the first lifting device and the second lifting device to the same height.

4. The first lifting device and the second lifting device further include a level sensor that can detect a positional relationship between the first lifting device and the second lifting device in a vertical direction, The lifting system according to claim 3 , wherein the control device calculates the height difference based on a signal from the level sensor.

5. the level sensor includes a first water level meter attached to the first lifting device and a second water level meter attached to the second lifting device; the first water level gauge and the second water level gauge are configured so that liquids therein can move relative to each other; The lifting system according to claim 4 , wherein the control device calculates the elevation difference based on signals from the first water level gauge and the second water level gauge.

6. The lifting system according to claim 1 , wherein the structure is a building.

7. The lifting system of claim 6 , wherein the lifting stage surrounds the periphery of the building.

8. The lift system of claim 7 , wherein the controller moves up and down together with the lift stage.

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