JPH0735240B2 - Aerial work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention makes it possible to raise a worker or a material for work at a high place such as assembling a building at a high place and painting, and to eliminate the need for the work. As for the aerial work vehicle used to unload unloaded materials from a high position, in particular, the entire lifting mechanism for lifting the lifting platform is formed by three hydraulic expansion and contraction mechanisms similar to hydraulic cylinders. The present invention relates to an aerial work vehicle capable of synchronizing the mechanisms.

[Conventional technology]

For assembling, painting, and repairing in high places such as highways and building construction, many aerial work vehicles that raise and lower the elevator are used, and workers, materials, etc. are placed on the elevator and lifted.
I was working on loading and unloading unnecessary materials.

In a conventional aerial work vehicle, a pantograph-like expansion / contraction mechanism in which a pair of arms are axially connected to form a set and a plurality of sets of arms are vertically connected (so-called scissors type) is used. In this configuration, in order to increase the maximum rising height of the lifting platform, it is necessary to increase the length of the arms of each set or increase the number of arms to be connected. For this reason, if a lifting mechanism that can raise the lifting height is designed, a large number of sets of pantographs must be used, and the height of the lifting mechanism when the pantograph is folded becomes high, so that the worker can use it as a lifting platform. The work of getting on and off, loading and unloading materials was troublesome.

In order to eliminate this drawback, various proposals have hitherto been made, and for example, a structure as disclosed in US Pat. No. 3820631 has also been proposed. In this structure, the lower boom and the upper boom that can move linearly with respect to the middle boom are inserted and removed freely, and the lower boom is pivotally supported by the pin on the vehicle body side at the lower end of the upper boom. Is assembled to form an X-shape by pivotally supporting the upper end of the base on a platform with a pin. With this structure, the length of the boom itself becomes long, so that the height of the platform can be reduced when the boom is folded, and the platform can be lifted to a high position.

However, in the present invention, since the mechanism for extending the lower boom and the upper boom from the middle boom is composed of the screw and the female screw meshing with the screw, the expansion and contraction moving speed of the lower boom and the upper boom relative to the middle boom is slow, and the platform can be quickly moved. It couldn't be moved. Also, since the lower boom and the upper boom are slid by the screw provided in the center of each middle boom, the total length of the lower boom and the upper boom can only be set to about half the length of the middle boom. The length of the lower boom and the upper boom can be extended by about half the length of the middle boom by expanding and contracting from the middle boom, and the platform could not be lifted higher.

In addition, a structure has been proposed in which another boom is inserted into the boom to extend and retract the boom itself. For example, in Japanese Patent Laid-Open Publication No. 119556 of 1978, in FIG. 4 of the drawing, in FIG. 4 of the drawing, a multi-stage boom having a small diameter and an upper boom are inserted into a thick middle boom and inserted inside. It has been proposed to extend the boom length by pulling the boom out of the middle boom, thereby raising the platform high.

However, in the present invention, there is no mechanism for synchronizing the expansion and contraction amounts between the lower boom and the upper boom that are pulled out from the middle boom, and they move individually, and the movement amount is regulated by the bar link mechanism. I am letting you.
For this reason, the platform cannot be lifted in the vertical direction while being held horizontally, and cannot be lifted up to the target vertical height position. Also, when the lower boom and the upper boom housed in the middle boom expand and contract, the movement amount of them is regulated by the link mechanism formed by the bar, so it is impossible to completely synchronize the movement amounts of the two. is there. For this reason, the lower boom cannot be connected to the vehicle body and the upper boom to the platform by pins, and an error that cannot be synchronized has to be made by the rollers in contact with the vehicle body and the platform. For this reason, the platform receives the rolling by the link mechanism as it is,
The structure was apt to shake, and it was extremely unstable because it easily rocked due to wind and the like, which gave workers anxiety.

Further, in FIG. 4 in the drawing, the X-shaped middle stage boom is rotated by a hydraulic cylinder attached to the outside, and the lower stage boom and the upper stage boom are pulled out by the rotation of the middle stage boom. It is shown. The amount of withdrawal is regulated by the link mechanism of each of the upper and lower booms, but the operating force of the hydraulic cylinder is the upper stage when the hydraulic cylinder that linearly acts on the upper and lower booms is pulled out to the maximum. The lengths of the boom and lower boom are not as extended as the full length of the middle boom. Therefore, it has been impossible to make the maximum extension length of the expanding and contracting boom itself extremely long.

Next, since it is possible to extend the entire length of the folded boom over its length, for example, Japanese Patent Laid-Open No.
A configuration like the issue is also proposed.

In this configuration, the outrigger box is horizontally fixed to a part of the vehicle body, the inside of the outrigger box is divided by partition walls, and the outrigger beam is slidably inserted into each storage chamber. A working cylinder is stored in the room. And both outrigger beams are connected by a rope.

In this configuration, by operating the actuation cylinder, the outrigger beams can be retracted from within the outrigger box, both outrigger beams can move in opposite directions, and each outrigger beam that is pulled out from within the outrigger box is the length of the outrigger box. It can be stretched to some extent. This configuration is effective in extending the outrigger beam from the outrigger box for a long time.

However, this configuration is for an outrigger for lifting the vehicle body and fixing it to the ground, and even if it is diverted to an aerial work vehicle as it is, the lifting platform cannot be moved up and down. In addition, in the drawings described in this publication, both ends of both outrigger beams are not connected to any structures, but a configuration is shown in which the outrigger beams are freely expanded and contracted in the left and right horizontal directions. It is nothing more than a thing.

From such a point of view, there have been proposed a number of elevating mechanisms configured such that a plurality of booms can be telescopically inserted inside the arm and one arm can be extended in the length direction thereof. For example, Japanese Patent Application No. 134487/1983, Japanese Patent Application No. 191065/1981 and the like can be mentioned.

In these new lifting mechanisms, booms with three steps extend in their respective length directions, and the middle boom that has been assembled into an X shape is rotated, so that the vehicle body and the lifting platform are viewed from the side in an X shape. It is configured so that the lifting platform can be raised to a high position. Further, since the tips of the lower boom and the upper boom are connected to the vehicle body or the lifting platform by pins, the rattling is small and a strong holding force against shaking can be exerted.

In addition, in these newly proposed lifting mechanisms that use telescopic booms that can expand and contract in multiple stages, in order to extend and retract the lower and upper booms from the middle boom, the hydraulic pressure interposed between the vehicle body and the center of the middle boom is used. A structure was used in which the middle boom itself was lifted by a cylinder, or a lower cylinder or an upper boom was extended by a hydraulic cylinder inserted in the middle boom, respectively.

In this configuration, since each hydraulic cylinder must be used, the upper boom and the lower boom must be synchronized with each other, and a mechanism for synchronizing with a chain or wire must be provided without fail. As a result, the lifting mechanism itself has a drawback of increasing its weight.

[Problems to be Solved by the Invention]

According to the present invention, unlike the conventional X-shaped lifting mechanism, the lower boom and the upper boom are inserted inside the middle boom, and the hydraulic cylinder is not provided inside the lower boom. It is intended to expand and contract the entire length by itself. For this reason, the outer shell of the hydraulic cylinder is made the same cylinder body as the conventional middle boom, and the thick rod and the thin rod are elastically inserted from the upper end and the lower end of this cylinder body, respectively. It is an object to provide an aerial work vehicle that can simplify the configuration by eliminating a tuning mechanism such as a hydraulic cylinder or a wire.

Now, in order to use this hydraulic expansion / contraction mechanism that stretches in three stages in a stable manner, at least three hydraulic expansion / contraction mechanisms are required, and each of these three hydraulic expansion / contraction mechanisms can be freely rotated at its center. Must be configured so that it has an X shape when viewed from the side. With such an X-shaped configuration, the hydraulic expansion / contraction mechanism can stably raise the lifting platform with a minimum number of units.

However, with such a configuration, the expansion and contraction amounts of the central hydraulic expansion and contraction mechanism and the hydraulic expansion and contraction mechanisms on both sides must be synchronized, and the conventional synchronization mechanism such as a wire cannot be attached. For this reason, a new synchronization means different from the conventional mechanical synchronization mechanism has to be considered.

[Means for Solving the Problems]

The present invention relates to an aerial work including a movable vehicle body, a lift table that can be moved up and down above the vehicle body, and a lifting mechanism that is interposed between the vehicle body and the lift table to lift and lower the lift table by hydraulic pressure. In a vehicle, the lifting mechanism uses three hydraulic expansion / contraction mechanisms that can be expanded / contracted in three stages, and the central parts of the hydraulic expansion / contraction mechanisms are rotatably configured in an X shape. Each hydraulic expansion / contraction mechanism has a large diameter. It consists of a cylinder body, a thick rod inserted into this cylinder body, and a thin rod inserted into this thick rod. The thick rod of the hydraulic expansion and contraction mechanism in the center is connected to one end of the upper surface of the vehicle body and is on both sides. The thick rods of the two hydraulic expansion / contraction mechanisms are connected to the other end of the upper surface of the vehicle body, and the thin rods of the hydraulic expansion / contraction mechanism in the center are connected to the other end of the lower surface of the lifting platform. Make sure that the rod is connected to one end of the lower surface of the elevator. It is intended to provide aerial work platforms to butterflies.

[Action]

In the present invention, the three hydraulic expansion / contraction mechanisms are alternately arranged in the center and on the left and right sides thereof, the thick rod of the central hydraulic expansion / contraction mechanism is at one end of the upper surface of the vehicle body, and the thick rod of the left and right hydraulic expansion / contraction mechanisms is at the other end of the upper surface of the vehicle body. Are linked to. Then, the pressure cross-sectional area of the cylinder chamber in the thick rod of the central hydraulic cylinder and the total hydraulic cross-sectional area of the cylinder chambers of the two thin rods on the left and right are made the same, and by connecting both cylinder chambers, the central hydraulic expansion / contraction mechanism It is intended to measure the expansion and contraction amount of the left and right hydraulic expansion and contraction mechanisms.

The hydraulic cross-sectional area of the left and right thin rods of the hydraulic expansion and contraction mechanism is half the hydraulic cross-sectional area of the thick rod of the hydraulic expansion and contraction mechanism in the center, and the pressure oil discharged from the cylinder chambers of the two left and right thin rods is It is supplied to the thick rod cylinder chamber of the central hydraulic expansion mechanism. Therefore, the thin rods of the left and right hydraulic expansion / contraction mechanisms and the thick rod expansion / contraction amounts of the central hydraulic expansion / contraction mechanism are completely the same. Therefore, the three hydraulic expansion / contraction mechanisms that are rotatably connected in the center rotate in an X shape, and the vehicle body, the lifting platform, and the hydraulic expansion / contraction mechanism expand and contract to form an X shape when viewed from the side. The three hydraulic expansion / contraction mechanisms can be alternately rotated at the center thereof. For this reason, both upper ends of the center and the left and right hydraulic expansion / contraction mechanisms are held at the same height, and the elevating table can always be raised while being kept horizontally.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a state in which the lifting platform of an aerial work vehicle according to this embodiment is raised to the maximum height position, FIG. 2 is a side view of the same as above, and FIG. FIG. 4 is a rear view showing a state in which it is lifted to the position, and FIG. 4 is a side view showing a state in which the lift is lowered to the lowest height position.

In this figure, reference numeral 1 is a vehicle body of a truck, and front and rear wheels 2 and 3 are axially supported on the front, rear, left and right sides of the vehicle body 1, and a cabin 4 accommodating a driver's seat inside is provided above the front wheel 2. It is fixed. Further, outriggers 5 for fixing the vehicle body 1 to the ground are fixed to the center and the left and right of the rear portion of the vehicle body 1. An elevating mechanism 6 is placed on the upper surface of the vehicle body 1, an elevating table 7 that moves vertically in the vertical direction is located on the upper surface of the elevating mechanism 6, and a kick mechanism 11 is provided at the center of the upper surface of the vehicle body 1. It is installed.

Next, the elevating mechanism 6 is composed of three hydraulic expansion / contraction mechanisms 8, 9, 10. The hydraulic expansion / contraction mechanisms 8, 9 and 10 have large diameter cylinder bodies 13, 16 and 19, and the cylinder body 13 and
Thick rods 14 and 1 that are telescopically inserted from one end of 16 and 19.
7, 20 and thin rods 15, 18, 21 inserted into the cylinder bodies 13, 16, 19 from the other end so as to extend and contract, and each cylinder body 1
It is composed of a connecting mechanism 22 that rotatably connects the centers of 3, 16, and 19. These three hydraulic expansion / contraction mechanisms 8, 9,
In the case of 10, the cylinder body 13 is arranged in the center, and the cylinder bodies 16 and 19 are arranged on the left and right of the cylinder body 13.
Make 3, 16, 19 staggered. The three hydraulic expansion / contraction mechanisms 8, 9 and 10 are axially connected to the inner center of the cylinder bodies 13, 16 and 19 by a connecting mechanism 22 so as to be rotatable relative to each other.

A connecting piece 23 is fixed to the lower end of the thick rod 14 of the central hydraulic expansion / contraction mechanism 8, and a connecting piece 24 is fixed to the upper end of the thin rod 15 of the hydraulic expansion / contraction mechanism 8. This thick rod
The connecting piece 23 of 14 is rotatably connected by a pin to a fixed piece 25 fixed to the rear center of the vehicle body 1 (on the rear wheel 3 side).
Further, the connecting piece 24 of the thin rod 15 of the hydraulic expansion / contraction mechanism 8 is a fixed piece 26 fixed to the center of the lower surface of the lift table 7 (on the front wheel 2 side).
And is rotatably connected by a pin.

Further, connecting pieces 27 and 28 are fixed to the lower ends of the thick rods 17 and 20 of the left and right hydraulic expansion and contraction mechanisms 9 and 10, and are connected to the upper ends of the thin rods 18 and 21 of the hydraulic expansion and contraction mechanisms 9 and 10. Pieces 29 and 30 are fixed. Then, the connecting piece 27 of the thick rods 17 and 20,
28 is rotatably connected to the fixed pieces 31 and 32 fixed to the left and right of the front side of the vehicle body 1 (on the side of the front wheel 2) with a space therebetween by pins. Also, the connecting pieces 29, 30 of the thin rods 18, 21
Is rotatably connected to the fixed pieces 33, 34 fixed to the rear of the lower surface of the lift table 7 (on the rear wheel 3 side) by pins. That is, the hydraulic expansion / contraction mechanism 8 and the two hydraulic expansion / contraction mechanisms 9 and 10 are assembled so that their structures are the same (the sectional shapes are different. This shape will be described later), and the hydraulic expansion / contraction mechanism 8 is used. , 9 and 10 are cylinders of the same length 13, 1 respectively
6, 19, thick rods 14, 17, 20 and thin rods 15, 18, 21. Then, the central hydraulic expansion / contraction mechanism 8 and the hydraulic expansion / contraction mechanisms 9 and 10 on both sides are arranged on the vehicle body 1 in opposite directions.

In this way, the X-shaped structure is formed by the vehicle body 1, the lifting platform 7, and the lifting mechanism 6 when the aerial work vehicle is viewed from the side. Further, the spacing between the fixing pieces 25, 31 and 32 fixed to the front and rear of the upper surface of the vehicle body 1 and the spacing between the fixing pieces 26, 33 and 34 fixed to the front and rear of the lower surface of the lift table 7 are set to be the same. There is. Therefore, when the hydraulic expansion / contraction mechanisms 8, 9, and 10 are synchronously extended by the same amount, the elevating mechanism 6 rotates in an X shape, and the vehicle body 1 and the elevating table 7 are always parallel.

The kick mechanism 11 is provided in the center of the upper surface of the vehicle body 1 and is located between the fixing pieces 25 and 31, 32. The kick mechanism 11 is composed of a hydraulic cylinder 36 that expands and contracts in the vertical direction. At the upper end of the hydraulic cylinder 36, a push-up body that extends in the lateral direction and contacts the center of the lower surface of each hydraulic expansion and contraction mechanism 8, 9, 10. 37 is fixed horizontally.

Next, FIG. 5 shows in detail the insides of the hydraulic expansion / contraction mechanisms 9 and 10 constituting the lifting mechanism 6. FIG. 5 is a side cross-sectional view of the hydraulic expansion / contraction mechanism 9, and the internal structure of the hydraulic expansion / contraction mechanism 10 is the same as the internal structure of the hydraulic expansion / contraction mechanism 9 and is therefore omitted in the drawing.

The cylinder body 16 (19) of the hydraulic expansion / contraction mechanism 9 includes an outer case 41, a middle case 42, and an inner case 43. The inner diameter of the outer case 41 is formed to be slightly larger than the outer diameter of the thick rod 17 (20), and the outer diameter of the middle case 42 is set to be slightly smaller than the inner diameter of the thick rod 17 (20). The outer diameter of the thin rod 18 (21) is set to be slightly smaller than the inner diameter of the middle case 42, and the outer diameter of the inner case 43 is set to be smaller than the inner diameter of the thin rod 18 (21). Therefore, as shown in FIG. 7, the hydraulic expansion / contraction mechanisms 9 and 10 include an outer case 41, a thick rod 17 (20), a middle case 42, and a thin rod.
18 (21), the inner case 43 is concentrically arranged, and is formed so that the inner and outer diameters of the inner case 43 are slightly different from each other, and a gap is formed so that each member can freely move with respect to each other. ing.

A ring-shaped end ring 44 is fixed to the left end of the outer case 41 in FIG. A ring-shaped slide ring 45 is closely attached to the left side of the end ring 44, and the end ring 44 and the slide ring 45 have a plurality of screws.
It is fixed by 46. The inner diameter of the end ring 44 is made substantially the same as the inner diameter of the outer case 41, but the inner diameter of the slide ring 45 is made substantially equal to the outer diameter of the thick rod 17 (20), and the thick rod 17 (20) is This slide ring
It will slide while making airtight contact with the inner circumference of 45.

An end ring 47 is fixed to the right side of the outer case 41 in FIG. 5, and a slide ring 48 is closely fixed to the right side of the end ring 47. This end ring
The inner diameter of 47 is almost the same as the inner diameter of the inner case 42, the inner diameter of the slide ring 48 is almost the same as the outer diameter of the thin rod 18 (21), and the thin rod 18 (21) is airtight with this slide ring 48. It will slide while touching.

An end ring 49 having an outer diameter substantially the same as the inner case 42 and an inner diameter substantially the same as the inner case 43 is airtightly connected to the left end of the middle case 42 in FIG. A slide ring 50 is fixed to the left end of the with a plurality of screws 51. At the same time, the right side of the end ring 49 is airtightly connected to the left end of the middle case 42. The outer diameter of the slide ring 50 is substantially the same as the inner diameter of the thick rod 17 (20), and the inner wall of the thick rod 17 (20) can slide while making airtight contact with the outer periphery of the slide ring 50. .

Further, an end ring 52 having an outer diameter substantially the same as the outer diameter of the inner case 43 is fixed to the right end of the inner case 43, and a slide ring 53 is closely attached to the right side of the end ring 52. The ring 52 and the slide ring 53 are fixed by a plurality of screws 54. The outer diameter of the slide ring 53 is almost the same as the inner diameter of the thin rod 18 (21), and the slide ring 53 is provided on the inner wall of the thin rod 18 (21).
It is possible to slide while making an airtight contact with the outer periphery of.

In this way, the outer case 41, the middle case 42, and the inner case 43
As a result, two spaces are formed concentrically inside the cylinder body 16 (19). This space has the same function as the pressure chamber of the hydraulic cylinder. The outer case 41
A ring-shaped piston ring between the inner case 42 and
55 is slidably inserted, and this piston ring 55
Can move airtightly in the cylindrical space formed by the outer case 41 and the middle case 42, and the right end of the thick rod 17 (20) is fixed to the left side of the piston ring 55.

Next, a ring-shaped piston ring 56 is inserted between the middle case 42 and the inner case 43, and the piston ring 56 hermetically seals a cylindrical space formed by the middle case 42 and the inner case 43. The left end of the thin rod 18 (21) is fixed to the right side of the piston ring 56.

A plurality of communication holes 57 for allowing pressure oil to flow are formed around the right end of the thick rod 17 (20), and pressure oil flows around the left end of the thin rod 18 (21). A plurality of communication holes 58 for opening are formed. Further, a plurality of communication holes 59 for allowing the pressure oil to flow inside and outside the middle case 42 are formed around the left end of the middle case 42.

In addition, oil passage holes 60 and 61 that are open to the outside are formed at two locations on the outer circumference of the end ring 47. Of this,
One oil passage hole 60 is communicated with the cylinder chamber C on the right side of the space formed by the outer case 41 and the middle case 42,
The other oil passage hole 61 communicates with the cylinder chamber F-1 on the right side of the space formed by the middle case 42 and the inner case 43.

In this way, the outer case 41, the middle case 42, and the inner case 43
As a result, inside the cylinder body 16 (19), a hermetically sealed space whose inner and outer circumferences are divided into two layers is formed. Further, these sealed spaces are divided by the piston rings 55 and 56, so that a total of four sealed spaces are formed. These pressure chambers are the cylinder chamber C formed by the outer case 41, the middle case 42 and the piston ring 55, the cylinder chamber D formed by the middle case 42, the inner case 43 and the piston ring 56, the outer case 41 and the thick rod 17. (20)
And the cylinder chamber E formed by the piston ring 55
-1, thick rod 17 (20), middle case 42 and piston ring
Cylinder chamber E-2 formed by 55, middle case 42
Cylinder chamber F-1 formed by thin rod 18 (21) and piston ring 56, thin rod 18 (21) and inner case
It is divided into a cylinder chamber F-2 formed by 43 and a piston ring 56.

Next, FIG. 6 shows in detail the inside of the hydraulic expansion / contraction mechanism 8 constituting the lifting mechanism 6.

The cylinder body 13 of the hydraulic expansion / contraction mechanism 8 is an outer case.
It is composed of 141, a middle case 142, and an inner case 143.
The inner diameter of the outer case 141 is formed to be slightly larger than the outer diameter of the thick rod 14, and the outer diameter of the middle case 142 is set to be slightly smaller than the inner diameter of the thick rod 14. The outer diameter of the thin rod 15 is set to be slightly smaller than the inner diameter of the middle case 142, and the outer diameter of the inner case 143 is set to the thin rod 15.
It is set smaller than the inner diameter of. Therefore, as shown in FIG. 7, the hydraulic expansion / contraction mechanism 8 includes the outer case 141, the thick rod 14,
The middle case 142, the thin rod 15, and the inner case 143 are concentrically arranged and formed so that the inner and outer diameters of the respective cases are slightly different from each other, and there is a gap so that each member can move freely relative to each other. Are formed.

A ring-shaped end ring 144 is fixed to the right end of the outer case 141 in FIG.
A slide ring 145 having a ring shape is closely attached to the right side of the, and the end ring 144 is fixed to the slide ring 145 by a plurality of screws 146. The inner diameter of this end ring 144 is made almost the same as the inner diameter of the outer case 141,
The inner diameter of the slide ring 145 is made substantially equal to the outer diameter of the thick rod 14, and the thick rod 14 is
It slides while making airtight contact with the inner circumference of 145.

Further, an end ring 147 is provided at the left end of the outer case 141 in FIG.
Is fixed, and a slide ring 148 is closely fixed to the left side of the end ring 147. The inner diameter of the end ring 147 is substantially the same as the inner diameter of the inner case 142, the inner diameter of the slide ring 148 is substantially the same as the outer diameter of the thin rod 15, and the thin rod 15 is the slide ring 14.
It will slide while contacting airtightly with 8.

An end ring 149 having an outer diameter substantially the same as the inner case 14 and an inner diameter substantially the same as the inner case 143 is airtightly connected to the right end of the inner case 142 in FIG. A slide ring 150 is fixed to the right side of the with a plurality of screws 151. At the same time, the end ring 149
The left side of is connected to the right end of the inner case 143 in an airtight manner.
The outer diameter of the slide ring 150 is substantially the same as the inner diameter of the thick rod 14, and the inner wall of the thick rod 14 can slide while making airtight contact with the outer circumference of the slide ring 150.

Further, an end ring 152 having an outer diameter substantially equal to the outer diameter of the inner case 143 is fixed to the left end of the inner case 143,
A slide ring 153 is closely attached to the left side of the end ring 152, and the end ring 152 and the slide ring 153 are fixed by a plurality of screws 154. The outer diameter of the slide ring 153 is substantially the same as the inner diameter of the thin rod 15, and the inner wall of the thin rod 15 can slide while being in airtight contact with the outer periphery of the slide ring 153.

In this way, outer case 141, middle case 142, inner case
Due to 143, two spaces are formed inside the cylinder body 13 concentrically. This space has the same function as the pressure chamber of the hydraulic cylinder. The outer case 141
A ring-shaped piston ring 155 is slidably inserted between the inner case 142 and the inner case 142, and the piston ring 155 moves airtight in a cylindrical space formed by the outer case 141 and the middle case 142. The left end of the thick rod 14 is fixed to the right side of the piston ring 155.

Next, a ring-shaped piston ring 156 is inserted between the middle case 142 and the inner case 143. This piston ring 156 can move airtightly in a cylindrical space formed by the middle case 142 and the inner case 143, and the right end of the thin rod 15 is fixed to the left side of the piston ring 156.

A plurality of communication holes 157 for flowing pressure oil are formed around the left end of the thick rod 14, and a communication hole 158 for flowing pressure oil is formed around the right end of the thin rod 15. There are multiple openings. Further, a plurality of communication holes 159 for allowing pressure oil to flow inside and outside the middle case 142 are opened at the left end of the middle case 142.

Further, oil passage holes 160 and 161 that are open to the outside are formed at two locations on the outer periphery of the end ring 147. Of these, one oil passage hole 160 communicates with the cylinder chamber L on the left side of the space formed by the outer case 141 and the middle case 142, and the other oil passage hole 161 has the middle case 142 and the inner case 143.
It communicates with the cylinder chamber P-1 on the left side of the space formed by.

In this way, outer case 141, middle case 142, inner case
By 143, a sealed space having an inner and outer circumference divided into two layers is formed inside the cylinder body 13. Further, these closed spaces are divided by the piston rings 155 and 156, and a total of four closed spaces are formed. These pressure chambers are a cylinder chamber L formed by an outer case 141, a middle case 142 and a piston ring 155, a cylinder chamber M formed by a middle case 142, an inner case 143 and a piston ring 156, an outer case 141 and a thick rod 14. And a cylinder chamber N-1 formed by the piston ring 155, a thick rod 14, a middle case 142, and a cylinder chamber N-2 formed by the piston ring 155, a middle case 142, a thin rod 15, and a piston ring 156. Cylinder chamber P-1, thin rod 15 and inner case 143
And a cylinder chamber P-2 formed by the piston ring 156.

As described above, the hydraulic expansion / contraction mechanism 9 (10) is configured,
The shape of each member in the hydraulic expander 9 (10) will be described.

The thick rods 17 (20), the thin rods 18 (21), the outer case 41, the middle case 42, and the inner case 43 allow the cylinder chambers C, D, E-1, E-2, in the hydraulic expansion / contraction mechanism 9 (10). F-1, F
-2 is partitioned. The sectional shape of the hydraulic expansion / contraction mechanism 9 (10) is shown in FIGS. 8 and 9. Of these, the 8th
The drawing shows a cross section taken along the line AA in FIG. 5, and FIG.
The cross section of the BB arrow in the figure is shown.

Since the above-mentioned cylinder chamber E-1 and the cylinder chamber E-2 are communicated with each other through the communication hole 57, the sectional area to which the hydraulic pressure is applied is the total of the sectional areas of both the cylinder chambers E-1 and E-2. It becomes E. Similarly, since the cylinder chamber F-1 and the cylinder chamber F-2 are communicated with each other through the communication hole 58, the area to which the hydraulic pressure is applied is the total cross-sectional area of both the cylinder chambers F-1 and F-2. Becomes In the initial design, these cross-sectional areas are set so that the total cross-sectional area E of the cylinder chambers E-1 and E-2 and the cross-sectional area of the cylinder chamber D are equal. By making the total cross-sectional area of these cylinder chambers E-1 and E-2 equal to the cross-sectional area of D, the thick rod 17
(20) and the amount of expansion and contraction of the thin rod 18 (21) can be synchronized.

Similarly, the shape of each member in the hydraulic expansion / contraction mechanism 8 will be described.

Thick rod 14, thin rod 15, outer case 141, middle case 142,
Cylinder chambers L, M, N-1, N-2, P-1, and P-2 are defined in the hydraulic expansion / contraction mechanism 8 by the inner case 143. The cross-sectional shape of this hydraulic expansion / contraction mechanism 8 is shown in FIG.
Shown in Figure 11. Of these, FIG. 10 shows JJ in FIG.
FIG. 11 shows a cross section taken along the arrow, and FIG. 11 shows a cross section taken along the line KK in FIG.

Since the above-mentioned cylinder chamber N-1 and the cylinder chamber N-2 are communicated with each other through the communication hole 57, the sectional area to which the hydraulic pressure is applied is the total of the sectional areas of both the cylinder chambers N-1 and N-2. N. Similarly, since the cylinder chamber P-1 and the cylinder chamber P-2 are communicated with each other through the communication hole 58, the area to which the hydraulic pressure is applied is the sum of the sectional areas of the cylinder chambers P-1 and P-2. Becomes In the initial design, these cross-sectional areas are set so that the total cross-sectional area N of the cylinder chambers N-1 and N-2 is equal to the cross-sectional area of the cylinder chamber M. By equalizing the total cross-sectional area of the cylinder chambers N-1 and N-2 and the cross-sectional area of M, the expansion and contraction amounts of the thick rod 14 and the thin rod 15 can be synchronized.

The sectional structure of the hydraulic expansion / contraction mechanism 8, 9, 10 is shown in FIGS. 8, 9, 10 and 11, and the central hydraulic expansion / contraction mechanism 8 and the hydraulic expansion / contraction mechanisms 9, 10 on both sides are shown. Are slightly different in shape. The thick rods 14, 17, 20 and the thin rods 15, 18, 21 of the hydraulic expansion / contraction mechanisms 8, 9, 10 have the same inner and outer diameters, respectively. However, outer cases 41 and 141, middle cases 42 and 1
It should be noted that the inner and outer diameters of the inner case 43 and the inner case 43 and 143 are different from each other.

First, in the hydraulic expansion / contraction mechanism 9 (10), the outer case 41 and the thick rod 17 (2) corresponding to the section taken along the line AA in FIG.
0), in the middle case 42, the cylinder chambers F-1 and F-2 are provided, but since both cylinder chambers F-1 and F-2 are communicated by the communication hole 58, the effective pressure cross-sectional area is F-1. The cross-sectional area E is the total of F-2. Then, the central hydraulic expansion / contraction mechanism 8
Then, corresponding to the cross section taken along the line JJ in FIG.
The outer case 141 and the middle case 142 form a cylinder chamber L. These cylinder chambers F-1, F-2, L
In this relationship, the total value of the cross-sectional areas F of the two cylinder chambers F-1 and F-2 is set to match the cross-sectional area of one cylinder chamber L (that is, 2 × F = L). By this setting, the outer case 41, 141, the middle case 42, 142, the inner case 4
The shapes of 3,143 are determined.

This shape is set by the thick rods 14, 17, 20 of the central hydraulic expansion / contraction mechanism 8 and the hydraulic expansion / contraction mechanisms 9, 10 on both sides, the thin rod 15,
This is to synchronize the expansion and contraction amounts of 18 and 21.

Next, the connecting mechanism 22 will be described in detail with reference to FIG. This connecting mechanism 22 includes three hydraulic expansion / contraction mechanisms 8, 9, 10
Can be rotatably connected to each other at their centers, and three hydraulic expansion / contraction mechanisms 8, 9 and 10 are integrally combined to constitute an elevating mechanism 6. .

First, a fixed band 70 wound around the outer periphery of the cylinder body 13 of the central hydraulic expansion / contraction mechanism 8 is fixed to the center thereof. Also, fixed bands 71 and 72, which are wound around the outer circumference in a band shape, are fixed. Then, on the side surfaces of the fixed bands 71, 72 on both the left and right sides, cylindrical rotation shafts 73, 74 are projected and fixed so as to be perpendicular to the axial direction of the cylinder bodies 16, 19, and this rotation is performed. Engagement grooves 75 and 76 are formed by cutting on the outer circumferences of the tips of the shafts 73 and 74 so as to go around the outer circumferences. In addition, a fixing band 70 wound around the central cylinder body 13
On the left and right side surfaces of the cylindrical body 13, cylindrical rotating cylinders 77 and 78 are fixed so as to project right and left so as to be perpendicular to the axial direction of the cylinder body 13. The inner diameters of the rotary cylinders 77 and 78 are substantially the same as the outer diameters of the rotary shafts 73 and 74. The rotary cylinder 77 is inserted into the rotary shaft 73, the rotary cylinder 78 is inserted into the rotary shaft 74, and three cylinder bodies are inserted. 13, 16, 19 can rotate relative to each other. Then, pin holes 79 are opened above and below the base of the rotary cylinder 77, and pin holes 80 are opened above and below the base of the rotary cylinder 78. This pin hole
Pins 83, 84 fixed to the engaging bodies 81, 82 are inserted in 79, 80. The tip of the pin 83 is fitted in the engaging groove 75, and the tip of the pin 84 is fitted in the engaging groove 76. Has been.
The rotary cylinders 73 and 74 are held by the pins 83 and 84 so as not to come off from the rotary cylinders 77 and 74. These engaging bodies 81, 82
Are fixed to rotating cylinders 77 and 78 by screws 85 and 86, respectively.

Next, FIG. 13 shows the connection of the hydraulic circuit in this embodiment.

The suction side of the hydraulic pump 90 driven by the engine 91 is connected to the oil tank 92, and the discharge side of the hydraulic pump 90 is connected to a direction switching type switching valve 93. The output of the switching valve 93 is connected to the oil passage holes 60-1 and 60-2 in the left and right hydraulic expansion / contraction mechanisms 9 and 10, and is also connected to the hydraulic cylinder 36 at the same time. Further, the return path of the switching valve 93 is connected to the oil passage hole 161 of the central hydraulic expansion / contraction mechanism 8 and also to the hydraulic cylinder 36. The oil passage hole 61-1 of the hydraulic expansion / contraction mechanism 9 and the oil passage hole 61-2 of the hydraulic expansion / contraction mechanism 10 are directly connected to each other, and these oil passage holes 61-1 and 61-2 are connected to each other. Oil passage hole 160
It is connected to the.

Next, the operation of this embodiment will be described.

In order to raise and lower the platform 7, the engine 91 mounted on the vehicle body 1 is operated, and the engine 91 is used to drive the hydraulic pump 90.
Is driven, and the pressure oil is sucked by the oil tank 92 to generate hydraulic pressure.

First, in order to raise the lift table 7, the switching valve 93 is operated to switch to the "normal" side. Then, the pressure oil is supplied to the oil passage holes 60-1 and 60-2 of the left and right hydraulic expansion and contraction mechanisms 9 and 10, respectively, and the pressure oil supplied from the oil passage holes 60-1 and 60-2 is transferred to the outer case 41. It is supplied to the ring-shaped cylinder chamber C formed by the middle case 42. Since the pressure oil increases the pressure in the cylinder chamber C, the piston ring 55
Acts so as to be pushed leftward in FIG. 5,
The thick rods 17 and 20 generate a force to push the cylinder bodies 16 and 17 to the left.

When the lift platform 7 is at the lowest position as shown in FIG. 4, the cylinder bodies 16 and 19, the thick rods 17 and 20, and the thin rods 18 and 21 are in parallel straight lines. Since they are arranged, no component force is generated in the direction of rotating around the connecting mechanism 22 in the X direction, and the elevating table 7 does not rise.
However, since the hydraulic pressure is also being supplied to the hydraulic cylinder 36 from the switching valve 93 at the same time, the hydraulic cylinder 36 operates to lift the push-up body 37 and deform it so that it is slightly X-shaped. By the action of the kick mechanism 11, the elevating mechanism 66 is changed from the state in which the three cylinder bodies 13, 16 and 19 are in parallel to the state in which it is crushed to an X-shape. Due to this initial deformation, the pressure oil is supplied to the left and right cylinder bodies 16 and 19, so that the X-axis with the coupling mechanism 22 as the center.
A component force is generated in the direction of turning in a letter shape.

As described above, the pressure oil supplied into the cylinder chambers C of the left and right cylinder bodies 16 and 19 pushes the piston ring 55 and pushes the thick rods 17 and 20 from the left end of the slide link 55, and gradually the hydraulic expansion and contraction mechanism 9, It works to extend the total length of 10. With the movement of this piston ring 55, the outer case
Cylinder chamber E- formed by 41 and middle case 42
1, the pressure oil remaining in E-2 is the flow hole
It passes through 59 and flows into the cylinder chamber D. At this time, the pressure oil in the cylinder chamber E-1 passes through the flow hole 57 and flows into the cylinder chamber E-2, so that the pressure oil does not remain.

The pressure oil flowing into the cylinder chamber D pushes the piston ring 56 to the right in FIG. 5 and pushes the thin rods 18 and 21 out from the right side of the slide rings 48 and 53. In this way, the thick rods 17 and 20 and the thin rods 18 and 21 extend from the left and right ends of the cylinder bodies 16 and 19, and gradually act to extend the entire length of the hydraulic expansion / contraction mechanisms 9 and 10.

At this time, in the relationship among the cylinder chambers E-1, E-2, and D, since the total cross-sectional area of the cylinder chambers E-1 and E-2 is equal to the cross-sectional area of the cylinder chamber D, the cylinder body 1
Thick rods 17, 20 extruded from 6, 19 and thin rods 18, 21
Have the same movement speed.

In this way, since the thick rods 17, 20 and the thin rods 18, 21 extend from the left and right ends of the cylinder bodies 16, 19, the total length of the hydraulic expansion / contraction mechanisms 9, 10 becomes long, and the cylinder chamber E-
Since the total cross-sectional area of 1 and E-2 and the cross-sectional area of the cylinder chamber D are the same, the speeds at which the thick rods 17 and 20 and the thin rods 18 and 21 extend from the cylinder bodies 16 and 19 are the same (pressure flowing in). Because the amount of oil is the same). Then, the pressure oil is supplied to the cylinder chamber D and the piston ring 56 moves to the fifth position.
When moving to the right in the figure, the piston ring 56 moves between the inner case 43 of the middle case 42 and the cylinder chamber F-1,
The pressure oil remaining in the F-2 is supplied to the oil passage holes 61-
It is discharged from 1, 62-2 to the outside.

The pressure oil discharged from both the cylinder chambers F-1 and F-2 will flow into the cylinder chamber L via the oil passage hole 160 of the hydraulic expansion / contraction mechanism 8 at the center. Since the pressure in the cylinder chamber L is increased in this way, the piston ring 155 moves between the outer case 141 and the middle case 142,
The thick rod 14 connected to the piston ring 155 acts so as to push it to the right in FIG.

Due to the movement of the piston ring 155, the cylinder chamber N
-1, The pressure oil in N-2 flows out from the flow hole 159,
The pressure in the cylinder chamber M will be increased. Therefore, the piston ring 156 between the middle case 142 and the inner case 143 is moved to the left in FIG. 6, and the thin rod 15 connected to the piston ring 156 is pushed out from the cylinder body 13 to the outside. Will be done. At the time of this movement, since the total cross-sectional area of the cylinder chambers N-1 and N-2 and the cross-sectional area of the cylinder chamber D are the same, the thick rod 14 and the thin rod 14 extruded from both ends of the cylinder body 13 respectively. The moving speed of the rod 15 is the same. Then, as the piston ring 156 moves, the cylinder chamber P-
The pressure oil in P1 and P-2 is discharged from the oil passage hole 161 to the outside, and is collected in the oil tank 92 via the switching valve 93.

By forming this series of pressure oil cycles,
Thick rods 14, 17, 2 in each hydraulic expansion / contraction mechanism 8, 9, 10
The extension speeds of the thin rods 15, 18, and 21 are the same, and the extension amounts of the hydraulic expansion / contraction mechanisms 8, 9 and 10 are exactly the same. Therefore, the lifting mechanism 6 turns into an X-shape and rotates,
The elevating table 7 can be raised while being kept horizontal.

In this way, the rods thicker than both ends of the cylinder bodies 13, 16 and 19
14, 17, 20 and the thin rods 15, 18, 21 respectively extend in the left-right direction, and the distance between the connecting pieces 20 and 26, 27 and 29, and 28 and 30 is gradually enlarged. The total length of the lifting mechanism 6 which is a combination of three stages due to the extension of the hydraulic expansion / contraction mechanisms 8, 9 and 10 becomes long, but the thick rods 14, 17 and 20 and the thin rod 1 are
5, 18, 21 are connected at their tips to fixing pieces 25, 26, 31, 32, 33, 34, which are fixed between the vehicle body 1 and the lifting table 7, so that the total length is extended. Then, the force is exerted so that the direction in which the entire length extends becomes upward, and the lifting platform 7 is gradually lifted upward. At this time, the three cylinder bodies 13, 16 and 19 are respectively the rotary shafts 73 and 74 and the rotary cylinder.
Since they are connected by 77 and 78, each is a rotating shaft
The center axes of 73 and 74 are rotated about the center of rotation so as to form an X shape, and the lifting mechanism 6 is started up.

When the lifting mechanism 7 has risen to a certain height, the switching valve 93 is switched to "neutral" so that the oil passage hole 60
Since the supply of pressure oil to -1, 60-2 is cut off and the piston rings 55, 56 are held in their stopped positions,
The lifting platform 7 will be maintained at that height position.

On the contrary, in order to lower the lifting table 7, the switching valve 93 is switched in the "reverse" direction contrary to the above, the pressure oil is added to the oil passage hole 161 of the central hydraulic expansion mechanism, and the cylinder chamber P-1. , P
-Increase the pressure of -2. As a result, the piston ring 156 is pushed to the right in FIG. 6, and the thin rod 15 becomes a cylinder body.
13, the pressure oil in the cylinder chamber M increases the pressure in the cylinder chambers N-1 and N-2 through the flow hole 159, pushing the piston ring 155 to the left in FIG. 14 is retracted toward the inside of the cylinder body 13. Thus, the distance between the lower end of the thick rod 14 and the upper end of the thin rod 15 is reduced.

Then, the pressure oil remaining in the cylinder chamber L is the oil passage hole.
The pressure oil discharged from 160 is supplied to the oil passage holes 61-1 and 61-2 of the left and right hydraulic expansion / contraction mechanisms 9 and 10, respectively, and the thick rods 17 and 20 and the thin rods 18 and 21 are connected to the cylinder body 1 respectively.
It acts so as to be able to retract inside the 6 and 19. For this reason, the entire length of each hydraulic expansion / contraction mechanism 8, 9, 10 is shortened, and the elevating table 7 is gradually lowered, contrary to the above. At this time, the cross-sectional area of the cylinder chamber M and the cylinder chambers N-1, N
Since the total cross-sectional area of −2 is the same, the speeds at which the thick rod 14 and the thin rod 15 are drawn into the cylinder body 13 are the same. Further, since the total cross-sectional area of the cylinder chambers F-1 and F-2 is equal to the cross-sectional area of the cylinder chamber D, the cylinder body
The pulling speeds of the thick rods 17 and 20 and the thin rods 18 and 21 of 16 and 19 are the same. Furthermore, since the cross-sectional area of the cylinder chamber L is equal to the total cross-sectional area of the two cylinder chambers F-1 and F-2 in the left and right cylinder bodies 16 and 19,
The retracting speed of the thick rod 14 in the hydraulic expanding / contracting mechanism 8 and the retracting speed of the thick rods 17 and 20 in the hydraulic expanding / contracting mechanisms 9 and 10 on the left and right are the same. Therefore, the three hydraulic expansion / contraction mechanisms 8,
The pulling-in speeds of the thick rods 14, 17, 20 and the thin rods 15, 18, 21 in 9 and 10 are the same, and the lifting platform 7 is lowered while maintaining horizontal.

When lowering the lift table 7, each pressure oil in the cylinder chamber C is returned to the oil tank 92 via the switching valve 93.

〔The invention's effect〕

Since the present invention is configured as described above, the lifting mechanism can be configured by a hydraulic expansion / contraction mechanism similar to a plurality of hydraulic cylinders, and the structure is extremely simple. Moreover, in the present invention, since the three hydraulic expansion / contraction mechanisms are used, the manufacturing cost can be reduced with the minimum required number. Further, when synchronizing the three hydraulic expansion / contraction mechanisms, the expansion / contraction speeds of the three hydraulic expansion / contraction mechanisms are always synchronized by setting the cross-sectional area in the specific cylinder chamber to which pressure oil is applied to a specific value. The synchronization mechanism is extremely simple and the operation can be stabilized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a work platform of an aerial work vehicle according to an embodiment of the present invention, in which FIG. 2 is a side view of the same, FIG. 3 is a rear view of the same, and FIG. FIG. 5 is a side view showing a state in which the lifting platform is lowered to the lowest position, FIG. 5 is a side sectional view showing the internal structure of the hydraulic expansion / contraction mechanism on the left and right, and FIG. 6 shows the internal structure of the central hydraulic expansion / contraction mechanism. FIG. 7 is a side sectional view, FIG. 7 is a longitudinal sectional view showing the internal structure when three hydraulic expansion / contraction mechanisms are combined, and FIG. 8 is a cross section of the hydraulic expansion / contraction mechanisms on the left and right taken along the line AA in FIG. Fig. 9 is a sectional view taken along the line B-B in Fig. 5, Fig. 10 is a sectional view taken along the line J-J in Fig. 6 of the hydraulic expansion / contraction mechanism at the center, and Fig. 11 is the same as above. 5 KK
FIG. 12 is a cross-sectional view taken along the arrow, FIG. 12 is an exploded perspective view showing the structure of a connecting mechanism that rotatably connects three hydraulic expansion / contraction mechanisms, and FIG. 13 is a piping diagram showing the structure of a hydraulic circuit in this embodiment. . 1 ... Car body, 6 ... Lifting mechanism, 7 ... Lifting platform, 8, 9,
10 …… Hydraulic expansion / contraction mechanism, 13, 16, 19 …… Cylinder body, 1
4, 17, 20 …… Thick rod, 15, 18, 21 …… Thin rod,
C, D, E, F, L, M, N, P ... Cylinder chamber.

Claims (1)

[Claims] 1. A high place having a movable vehicle body, an elevating table that can be moved up and down above the vehicle body, and an elevating mechanism that is interposed between the vehicle body and the elevating table to elevate the elevating table hydraulically. In the work vehicle, the lifting mechanism uses three hydraulic expansion / contraction mechanisms that can be expanded / contracted in three stages, and the center of these is connected to rotate in an X-shape. Each hydraulic expansion / contraction mechanism has a large diameter. It consists of a cylinder body, a thick rod inserted into this cylinder body, and a thin rod inserted into this thick rod.The thick rod of the hydraulic expansion and contraction mechanism in the center is connected to one end of the upper surface of the vehicle body, A thick rod of two hydraulic expansion / contraction mechanisms is connected to the other end of the upper surface of the vehicle body, and a thin rod of the hydraulic expansion / contraction mechanism in the center is connected to the other end of the lower surface of the lifting platform. The thin rod is connected to one end of the lower surface of the lift. Aerial according to claim.