JPH0335239B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a lifting device used for lifting workers or materials and lowering unnecessary parts for work at heights, and particularly relates to The middle boom is pivoted in an X-shape, and an upper boom and a lower boom that expand and contract in the axial direction are inserted into each middle boom, and the hydraulic pressure of a pair of hydraulic cylinders that lift the middle boom is adjusted to move the platform up and down. This invention relates to an elevating device that can be moved up and down both horizontally and horizontally.

[Conventional technology]

Assembly at high places such as highways and building construction,
For painting and repairs, a lifting device was used to raise and lower a lifting platform, and workers and materials were placed on this lifting platform to be lifted and lowered.

The outline of this conventional lifting device is explained with reference to Fig. 1. The middle booms A and B, which are hollow inside, are rotatably connected in an X-shape at the center by a shaft C. Upper booms D and E and lower booms F and G are inserted into the end faces so that they can appear and retract freely, and a lifting platform 1 is connected to the upper booms D and E, and a base is connected to the lower booms F and G. H
are connected. Between this base H and axis C, there is a pair of hydraulic cylinders J and K arranged in an isosceles triangle.
is interposed.

In this configuration, to raise the platform I, first raise the shaft C using hydraulic cylinders J and K, and then the upper booms D and E and the lower booms F and G are pulled out from the open ends of the middle booms A and B. , the lifting platform I moves upward away from the base H and rises. Here, in order for the lifting platform I to rise vertically upward with respect to the base H, upper booms D and E, lower booms F and G are required.
The amount of movement l drawn out from the open end of the middle booms A and B must always be the same, and therefore a synchronization mechanism that regulates the amount of movement of each of the upper booms D and E and the lower booms F and G is required. It is provided.

[Problem that the invention seeks to solve]

By the way, the total length of the middle boom B, the upper boom E, and the lower boom G is a, the total length of the middle boom A, the upper boom D, and the lower boom F is b, and the base H Letting h be the height from to the lifting platform I, the relationship shown in FIG. 2 holds true. Lifting platform I raised to a height h in this way
As an elevating device for laterally moving an arbitrary length L, the device described in Japanese Patent Application Laid-open No. 124972 of 1982 is generally provided. According to such a lifting device, the length of one boom is constant (in this conventional example, length a), and the length of the other boom is shortened (in this conventional example, from length b to length b ₁ ), the workbench I can be moved by a distance L. However, such a lifting device has a problem in that when the lifting table I is moved horizontally by a distance L, the height of the lifting table I becomes _h1 .

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an elevating device in which the height of the elevating platform can be maintained substantially constant even if the elevating platform moves horizontally.

[Means to solve the problem]

The lifting device of the present invention that solves the above problems is based on the following principle. Now, the principle of the lifting device of the present invention will be explained using FIG. 3. In this figure as well, the same items as in FIG. 2 will be described with the same reference numerals. Here, M is the length of the lifting platform I, and is also the distance between the pivot points of the lower booms G and F.

First, when the elevator platform I is vertically raised by h and then stopped, the following equation holds true. That is, ^a2 = ^h2 + ^M2 , ^b2 = ^h2 + ^{M2∴h2 = a2} - ^M2 = ^b2 - ^M2 , where a=b...(1).

Next, when the elevator platform I is moved laterally by L, the following equation holds true.

That is, a _x ² = h ² + (M+L) ² b _x ² = h ² + (M-L) ² ...(2). Substituting equation (1) into equation (2), a _x ² = a ² −M ² +M ² +2ML+L ² = a ² +2ML+ ^{L 2} b _x ² = a ² −M ² +M 2 −2ML+L ² = a ² − 2ML+L ² ...(3).

Therefore, by using the distance L as a variable, calculating a _x and b _x moment by moment, and comparing this with the actual extension amount of the boom, an arbitrary distance L can be obtained while maintaining the height h. can be moved horizontally. Furthermore, using equation (2), h and L
If _{ax and bx} are calculated moment by moment using ax and bx as variables, and the actual boom length is compared based on these values, the length of the boom can be controlled, making it possible to move up and down diagonally. In other words, by substituting a constant height Δ′h and a predetermined distance ΔL into equation (2), Δa _x ² = Δ′h ² + (M+ΔL) ² Δb _x ² = Δ′h ² + (M− ΔL) ² ...(4) is obtained, and if it is stopped when ΣΔ′h=h and ΣΔL=L, it becomes possible to ascend diagonally. In addition, when lowering, it is sufficient to stop when h-ΣΔ'h=0 and L-ΣΔL=0.

Based on such knowledge, the lifting device of the present invention has the following features:
A pair of internally hollow middle booms are rotatably connected in an X-shape approximately at the center of each, and an upper boom and a lower boom, which extend and contract at their respective ends, are slidably inserted into each middle boom, and the lower Each end of the boom is pivoted to the base at intervals, each end of the upper boom is pivoted to the lifting platform at intervals, and two points are located at approximately the center of the middle boom and the base. It consists of at least a pair of hydraulic cylinders arranged in an inverted V-shape between the hydraulic cylinders, and by expanding and contracting both hydraulic cylinders, the middle boom is moved up and down, and at the same time, the upper and lower booms are synchronized from the middle boom. In an elevating device that raises and lowers an elevating platform by sliding the elevating platform, the boom is equipped with a length measuring sensor that can measure the length of both X-shaped booms and output it as a detection signal. A hydraulic circuit that can individually supply pressure oil is provided, and a control device is provided that receives detection signals from the length measurement sensor and outputs control signals for driving and controlling the hydraulic circuit based on these signals. , a means for outputting a control signal to the hydraulic circuit to synchronize the expansion and contraction of both cylinders during lifting and lowering; a height of the lifting platform is h; a distance between the ends of the upper boom or lower boom is M; When the horizontal distance that the platform is going to move is L, the length of one of the booms when it moves is a _x , and the length of the other boom is b _x , then a _x ² = h ² + (M + L) ² b A means for calculating _x ² = h ² + (ML) ² and controlling the amount of expansion and contraction of each cylinder so that the lengths of a _x and b _x obtained by calculating with this means are obtained. The present invention is characterized by comprising means for outputting a control signal.

[Effect]

When the control device outputs a lift command, the hydraulic circuit operates and pressure oil is supplied to both cylinders.
At this time, the control device compares the detection signals from the length measurement sensors, and the control device controls the hydraulic circuit so that the control result becomes zero. As a result, the amounts of expansion and contraction of both cylinders are synchronized.

When the lifting platform reaches a predetermined height, a stop control signal is supplied from the control device to the hydraulic circuit, so that the pressure oil is trapped in the circuit and both cylinders remain extended. The height of the elevator platform at this time is stored in the control device, and based on this height, the length of the boom corresponding to the horizontal movement distance is determined. In order for the detection signal from the length measurement sensor to match this determined value,
A hydraulic circuit is controlled by a control device. This allows the platform to move horizontally while maintaining its height. Note that if the height and horizontal movement distance are given, it is also possible to move up and down diagonally.

〔Example〕

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 4 is a side view of an embodiment of the elevating device according to the present invention, showing the elevating mechanism in the lowest position. FIG. 5 is a side view showing the elevating mechanism in a fully extended state. FIG. 6 is a rear view showing the state in FIG. 5.

The reference numeral 1 in the figure is a truck body.A front wheel 2 and a rear wheel 3 are pivotally supported on the front, rear, left, and right sides of the vehicle body 1, respectively.A driver's cab 4 is provided above the front wheels 2. Outriggers 5 are fixed to the center and left and right sides of the rear end, respectively. An elevating mechanism 6 is placed on the upper surface of the vehicle body 1. A elevating table 7 is fixed to the upper part of the elevating mechanism 6, and a handrail 8 is provided around the elevating table 7. The lifting mechanism 6
consists of four telescoping booms, each with 10 middle booms and 1 lower boom.
1. It is composed of an upper boom 12. The center of each of the two middle booms 10 is connected by a connecting shaft 13 so as to be rotatable in an X-shape, and the lower boom 11 and the upper boom 12 each have a connecting piece at their tip. 14 and 15 are fixed to each other, and the connecting piece 14 is connected to the fixed piece 16 fixed on the vehicle body 1.
and are rotatably connected by a pin, and the connecting piece 1
5 is rotatably connected to a fixed piece 17 fixed to the lower surface of the lifting table 7 by a pin.

The intervals between the fixed pieces 16 and the fixed pieces 17 are the same, and the vehicle body 1 and the lifting platform 7 are configured to be parallel even if the telescopic boom is extended in an X-shape. The two sets of the middle booms 10 are arranged parallel to each other with an interval between them, and the middle booms 10 inside each set are connected at the center by an operating shaft 18. The axes of the actuating shaft 18 and the connecting shaft 13 are arranged in a straight line. Both positions close to the fixed piece 16 of the vehicle body 1 and the operating axis 1
Hydraulic cylinders 19 and 20 are arranged between the two hydraulic cylinders 8, respectively, and both the hydraulic cylinders 19 and 20 are arranged to form an isosceles triangle with the operating axis 18 as the apex. Note that the middle booms 10, 10 are provided with length measuring sensors 21, 22 for measuring the length of the booms. The length measurement sensors 21 and 22 connect potentiometers to the upper boom 1 via a gear mechanism.
2. It may be configured to mesh with the lower boom 11.

Next, FIGS. 7 and 8 show the internal structure of the above-mentioned telescopic boom, that is, the middle boom 10,
The middle stage boom 10 has a structure in which a thin steel plate is bent to have a hollow square cross section in the length direction, and a lower stage boom 11 is slidably inserted through one end of the middle stage boom 10. The lower boom 11 has a hollow rectangular cross section made by bending a thin steel plate, and the upper boom 12 inserted from the other open end of the middle boom 10 is slidably inserted into the lower boom 11. There is.

Fan-shaped shaft support pieces 23 and 24 are fixed to both ends of the middle boom 10, respectively, and a pair of guide rollers 25 and 26 are rotatably supported on the shaft support pieces 23 and 24, respectively. The guide rollers 25 are in contact with both sides of the lower boom 11, and the guide rollers 26 are in contact with both sides of the upper boom 12. A gearbox 27 is fixed to the end of the middle boom 10 close to the shaft support piece 24, and two sprocket wheels 28 and 29 are pivotally supported within the gearbox 27. The tip of the lower boom 11 (middle boom 10
The innermost position) and the tip of the upper boom 12 are connected by a chain 30, which is wound around the outer periphery of the sprocket wheels 28, 29 in an S-shape. This chain 30 connects the lower boom 11 and the upper boom 1.
2 are coordinated in their expansion and contraction amounts, and the middle boom 10, lower boom 11, and upper boom 12 move in and out by the same amount of expansion and contraction.

Further, FIG. 8 shows a cross section of the center of the middle boom 10, and a band-shaped holder 31 is wrapped around and fixed to the outer periphery of the center of the middle boom 10. A cylindrical connecting shaft 13 is fixed to the other holding body 31, and an engaging piece 33 fixed with a screw 32 is fixed to the other holding body 31.
By fitting the engaging piece 33 into an engaging groove 34 formed on the outer periphery of the connecting shaft 13, the two middle booms 10 are connected in an X-shape and their rotation is maintained freely. And one middle boom 1
A support shaft 3 is located on the opposite side of the connecting shaft 13 of the holder 31 of 0.
5 is projected, and the operating shaft 18 is connected to this support shaft 35.

FIG. 9 is a system diagram showing a schematic configuration of a hydraulic control system according to an embodiment of the present invention. In this figure, parts unrelated to the control system, such as the driver's cab 4, are omitted.

In the figure, it is attached to the middle boom 10,
A length measurement sensor 21 that can measure the amount of boom extension;
The detection signal from 22 is taken into the control device 50. The control device 50 includes a processing unit 51 that takes in various information, performs arithmetic processing on the information, and outputs a control signal, and a storage unit 52 that stores predetermined data and the like.
and an external operation panel 53. A control signal from the control device 50 is given to a first hydraulic control section 55 and a second hydraulic control section 56 of the hydraulic circuit 54, respectively. First hydraulic control section 55 and second hydraulic control section 5
The pressure oil controlled by 6 is supplied to hydraulic cylinders 19 and 2.
It is designed to flow in and out between 0 and 0.

FIG. 10 is a system diagram showing the detailed configuration of the hydraulic control system. The output of the engine 57 is transmitted to a pump 58, the suction side of the pump 58 is connected to a tank 59 filled with pressure oil, and the discharge side of the pump 58 is connected to switching valves 60, 61. The switching valves 60 and 61 are electromagnetic valves that can switch between three positions at high speed, and are connected to two oil passages 62, 63, 64, and 65, respectively. 19 and 20 are connected to each other, and a check valve 6 is connected to the oil passages 63 and 65.
The operating sides of the cylinders 19 and 20 are connected through a parallel circuit of the control valves 6 and 68 and the control valves 67 and 69.

The processing unit 51 of the control device 50 includes a microprocessor unit (MPU) 70 that performs various calculation processes,
A read-only memory (ROM) 71 that stores predetermined programs, etc., and a random access memory (RAM) 72 that stores processing programs, etc.
An analog-to-digital converter (ADC) 73 that converts detection signals from the length measurement sensors 21 and 22 into digital signals, and a digital input/output for capturing signals from the operation panel 53 and lighting the display section of the operation panel 53. (DIO) 74 and switching valves 60, 6
A digital output section (DO) 75 that outputs a control signal for switching between 1 and 2, and a backup RAM (Bu-RAM) that stores various data that must not be erased.
52, MPU70, ROM71, RAM72,
MDC73, Bu-RAM52, DIO74 and DO7
5 and a bus line 76 connecting the 5. Also,
The storage unit 52 is a backup RAM of the processing unit 51.
It is also used as.

The operation panel 53 is provided with a switch 80 for raising, a switch 81 for lowering, a switch 82 for horizontal movement, a switch 83 for storing height, and a switch 84 for selecting manual operation or automatic operation. It is connected to DIO 74 of section 51.

Next, the operation of this embodiment will be explained.

First, the engine 57 attached to the vehicle body 1 is operated, and the engine 57 drives the pump 57 to generate oil pressure. This oil pressure is the switching valve 60,6
However, when the switching valves 60 and 61 are in a stationary state, the hydraulic pressure is recovered to the oil tank 59 by a circuit (not shown).

Next, the operation will be explained using the flowchart shown in FIG.

FIG. 11 shows the result of manual operation.

At step 100 the program is started. In step 101, the lift switch 8 on the operation panel 53 is turned on.
When 0 is turned on, the process moves to step 102. In step 102, DIO 74 takes this in and
When applied to the MPU 70, the MPU 70 outputs an upward control signal to the switching valves 60 and 61 via the DI 75. As a result, hydraulic pressure is applied to the hydraulic cylinders 19 and 20 via the oil passages 62 and 64, and pressure oil is supplied into both the hydraulic cylinders 19 and 20. In step 103, the signals from the length measurement sensors 21 and 22 are taken into the Bu-RAM 52 via the ADC 73.
In step 104, the signals from the length measurement sensors 21 and 22 taken in are compared, and if there is a deviation in the comparison results, a control signal corresponding to the deviation is output to one of the switching valves 60 or 61. In step 105, the switching valves 60 and 61 are switched and controlled so that a predetermined amount of oil is supplied to the hydraulic cylinder 19 or 20 so that the deviation is eliminated. As a result, pressure oil is supplied to both hydraulic cylinders 19 and 20, and the hydraulic cylinder 19 is extended, and at the same time, the hydraulic cylinder 20 is extended in synchronization with the hydraulic cylinder 19. The pressure oil discharged by the hydraulic cylinders 19 and 20 passes through the control valves 67 and 69 to the oil tank 5.
It will be collected on 9th. When the hydraulic cylinders 19 and 20 are operated and their cylinder rods are projected, the middle boom 10 is lifted upward, and the lower boom 11 and the upper boom 12 are accordingly pulled out by the middle boom 10. Since the lower boom 11 and the upper boom 12 are connected by a chain 30, when the lower boom 11 comes out of the middle boom 10, the chain 30 fixed to the tip of the lower boom 11 is connected to the sprocket wheel 28,
Move this chain 30 while rotating 29.
With this movement, the lower end of the upper boom 12 is pulled, and the upper boom 12 is pulled out from the upper end opening of the middle boom 10. Moreover, since the chain 30 does not extend, the amount of extension of the lower boom 11 and the upper boom 12 is the same, and the amount of extension of each of the lower boom 11 and upper boom 12 in a pair is the same, and the amount of extension of the middle boom 10 is the same. The lifting platform 7 is lifted by rotating around the connecting shaft 13 in an X-shape. In pushing up the middle boom 10 by the hydraulic cylinders 19, 20, the hydraulic cylinders 19, 2
0 are arranged to form an isosceles triangle with the connecting shaft 13 at the center, so if the amount of extension of each cylinder rod is the same, the connecting shaft 13 will always be aligned with the vehicle body 1.
It will rise in the vertical direction. Both hydraulic cylinders 19 and 20 are synchronized so that the amount of extension thereof is the same, and the extension of the cylinder rod is the same amount at any time. To explain the relationship between this movement amount using FIG. 12, both hydraulic cylinders 1
The extension amount W of each boom 9 and 20 is the same, and the connecting shaft 13 is raised in a straight line, and the extrusion amount Z of the lower boom 11 and upper boom 12 is the same. The amount of movement will be synchronized.

In step 106, by controlling both hydraulic cylinders 19 and 20 in this way, it is determined whether or not the lifting platform 7 has reached a predetermined height h. If it has not reached the predetermined height h, the process returns to step 101, and if it has reached it, the raising switch 80 is turned on. is stopped (step 107).
As a result, the switching valves 60, 61 return to their neutral positions, and the hydraulic circuits of the respective hydraulic cylinders 19, 20 are closed while they are in the extended state, and the elevator platform 7 is not lowered (step 108). After stopping at a predetermined height, in step 109, the height h is determined by the MPU 70 using the detection signals of the length measurement sensors 21 and 22 and the above equation (1), and this is determined by the Bu-
Store it in RAM52. At this time, if you wish to perform automatic operation next time, you can ensure the reliability of the operation by pressing the memory switch 83.

In step 110, when the "forward movement" of the horizontal movement switch 82 is pressed, the process moves to step 111, where the MPU 70 calculates a _x and b _x moment by moment based on equation (3), and calculates the values. It is stored in Bu-RAM52.

In step 112, a control signal is given to the switching valves 60, 61 via the DO 75 so that the detection signals from the length measurement sensors 21, 22 match the above-determined a _x , b _x , and here, a _{x , b x} are determined. A comparison is made between b _x and the detection signal, and if they do not match, step 112 is repeated until they match. In step 113,
It is determined whether the lifting platform 7 has moved to a predetermined horizontal distance L, and if it has not moved, the process returns to step 110.
The process returns to step 114, and if it is moving, the process moves to step 114. In step 114, the switch 82 is stopped, and in step 115, the horizontal movement of the lifting platform 7 is stopped, and this distance L is stored in the Bu-RAM 52 by pressing the memory switch 83 or without operating it.
to be memorized.

In step 116, when the horizontal movement switch 82 is pressed for "backwards movement", the value stored in the Bu-RAM 52 is read out in reverse, and the detection signals from the length measurement sensors 21 and 22 are matched based on that value. The switching valves 60 and 61 are controlled accordingly. Step 11
7, lift platform 7 by distance L, that is, to the original position.
Determine whether the has moved, and if it has moved, proceed to step 1.
The process moves to step 18 and stops, and if it is not moving, the process moves to step 116. Next, in step 118, when the lowering switch 81 is pressed, in step 119,
A control signal is output from the DO 75 to the switching valves 60 and 61. As a result, the switching valves 60 and 61 are switched in the opposite direction, and the pressure oil from the pump 58 is transferred to the oil path 6.
3, 65, is injected into the hydraulic cylinders 19, 20 through the check valves 66, 68, and is injected into the hydraulic cylinders 19, 20.
shrinks. The hydraulic oil discharged by the hydraulic cylinders 19 and 20 is transferred to the oil tank 59 from the oil passages 62 and 64.
Return to Even when the two hydraulic cylinders 19 and 20 are contracted, the MPU 70 synchronizes them, so the contraction amounts of the two hydraulic cylinders 19 and 20 are synchronous, and the connecting shaft 13 of the middle boom 10 is perpendicular to the vehicle body 3. descend to In step 120, if the bottom has not been reached, the process returns to step 118; if it has been reached, the process moves to step 121. Step 121
to stop everything and end this routine.

According to this embodiment, the automatic operation switch 84
When the height h and the horizontal distance L are set, Δa _x and Δb _x are calculated using the above equation (4), and these are used as the reference, and the length measurement sensors 21 and 22 are
the switching valves 60, 6 so that the detection signals from the switching valves 60 and 6 match.
1 with the control signal 50, the lifting platform 7
will go up and down diagonally.

In the above embodiment, since the switching valves 60 and 61 are capable of opening and closing in a pulsed manner, it is easy to finely adjust the amount of movement. In addition, length measurement sensors 21, 2
2 may be a digital type, and in this case, the detection symbol is inputted to DIO 74.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to horizontally move while maintaining a constant height.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an outline of a conventional lifting device;
Fig. 2 is a schematic diagram shown to explain the operation of a conventional lifting device, Fig. 3 is a schematic diagram shown to explain the principle of the present invention, and Fig. 4 shows the lifting mechanism in its lowest position. A side view showing an example of a lifting device,
Fig. 5 is a side view showing the elevating mechanism as described above in a fully extended state, Fig. 6 is a rear view of the state shown in Fig. 5, Fig. 7 is a side sectional view showing the inside of the middle boom, and Fig. 8 The figure is a longitudinal sectional view of the middle boom near the operating axis, FIG. 9 is a system diagram showing a control system of an embodiment of the lifting device of the present invention, and FIG. 10 is a system diagram showing FIG. 9 in detail. FIG. 11 is a flowchart shown to explain the operation of the control system, and FIG. 12 is a schematic diagram showing the relationship between the lifting mechanism and the hydraulic expansion and contraction mechanism. 1... Vehicle body, 6... Lifting device, 7... Lifting platform,
10...middle boom, 11...lower boom, 12
...Upper boom, 19,20...Hydraulic cylinder,
21, 22...Length measurement sensor, 50...Control device, 54...Hydraulic circuit.

Claims (1)

[Scope of Claims] 1 A pair of internally hollow middle booms are rotatably connected in an X-shape approximately at the center of each, and an upper boom and a lower boom that extend and contract at their respective ends are slid into each middle boom. Each end of the lower boom is pivoted to the base at intervals, each end of the upper boom is pivoted to the lifting platform at intervals, and the center of the middle boom and the base are movably inserted. It consists of at least a pair of hydraulic cylinders arranged in an inverted V-shape between two points with an interval of In a lifting device that raises and lowers a lifting platform by sliding the boom in synchronization with the middle boom, the boom is equipped with a length sensor that can measure the length of both X-shaped booms and output it as a detection signal. , and a hydraulic circuit capable of individually supplying pressure oil to each of the two hydraulic cylinders, and a control device that receives detection signals from the length measurement sensor and outputs control signals for driving and controlling the hydraulic circuit based on these signals. The control device includes: means for outputting a control signal to the hydraulic circuit to synchronize the expansion and contraction of both cylinders during lifting and lowering; When the distance between the booms is M, the horizontal distance the platform is moving is L, the length of one boom when it moves is a _x , and the length of the other boom is b _x , then a _x ² = h ² + (M + _L ) ² b _x ² = h ² ₊ (ML) ² . A lifting device characterized by comprising: means for outputting a control signal for controlling the amount of expansion and contraction of each.