JPH0733237B2 - Aerial work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is intended to raise workers or materials upwards or to construct a construction site for work at a high place such as assembling a building at a high place or painting. Regarding aerial work vehicles used for unloading unnecessary materials from a high position,
Compared to the short length of the lifting mechanism in the folded state,
The present invention relates to an aerial work vehicle that can lift a lifting platform to a higher position.

[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 lift are used, and it is not necessary to put workers, materials, etc. on the lift and lift it. I was working on loading and unloading the materials.

In this conventional lifting device, a pantograph-shaped expansion / contraction mechanism is used in which a pair of arms are pivotally attached at the center to form one set, and a plurality of sets of arms are vertically connected (so-called scissors type). In the mechanism, in order to increase the maximum rising height of the lifting device, it is necessary to increase the length of the arms of each set or increase the number of connected arms. Therefore, when designing an elevating device that can raise the height that can be raised, a large number of sets of pantographs must be used, and the height of the elevating device when the vantagraph is folded becomes high, so that workers can get on and off the platform. However, the work of loading and unloading materials was troublesome.

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

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 extension and movement speed of the lower boom and the upper boom relative to the middle boom is slow,
It was not possible to react the platform quickly. Also, since the lower and upper booms are slid by the bevel gears provided in the center of each middle boom, set the total length of the lower and upper booms to only half the length of the middle boom. I can't
The extension of the middle boom to the lower boom and the upper boom was only half the length of the middle boom, so the platform could not be lifted higher.

Also, a structure has been proposed in which another boom is inserted into the boom and extended to extend the entire length of the boom itself. For example, in Japanese Patent Laid-Open Publication No. 119556 of 1978, in FIG. 4 of the drawing, a lower boom and an upper boom having a smaller diameter are inserted into a middle boom having a larger diameter, and the lower boom and the upper boom inserted therein are inserted. It has been proposed to extend the boom length by pulling it out from the middle boom, thereby raising the platform high.

However, in this structure, there is no mechanism that synchronizes the expansion and contraction amount between the lower boom and the upper boom that are pulled out from the middle boom, they move individually, and the expansion and contraction amount is restricted by the link mechanism by the bar. There is. For this reason, the platform cannot be lifted horizontally in the vertical direction, and cannot be lifted to a desired vertical height position. Also, when the lower and upper booms housed in the middle boom are expanded and contracted, the link mechanism formed by the bar is used to regulate the amount of movement of each, so perfect synchronization of the amount of movement is impossible. Therefore, the lower boom and the upper boom cannot be connected to the platform by a pin or the like, and the error that cannot be synchronized has to be made by the roller contacting the vehicle body and the platform. For this reason, the platform is subject to cumulative rattling due to the large number of shaft fulcrums due to the link mechanism and rolling due to the rollers as it is, so it has a structure that easily shakes and easily rocks due to wind etc. And, it made the workers feel uneasy.

In order to solve these drawbacks, for example, patent application Showa 56
No. 41289 is proposed every year. In this application, the lower boom and the upper boom are inserted into the middle boom, and the ends of the lower boom and the upper boom are connected by flexible connecting means, and the connecting means is pivotally supported by the middle boom. It is a structure in which the moving direction is changed by the changing means. In this configuration, the lower boom is pulled out from the middle boom, and at the same time, the upper boom is pushed out from the middle boom and the upper boom, and the movement amount of the lower boom and the upper boom is restricted by the connecting means. The amount of movement is the same, and a pair of middle booms pivotally supported at the center of the booms can rotate in an X shape to push up the lifting platform vertically upward.

In this configuration, in order to store the lower boom and the upper boom in the middle boom, if the lower boom and the upper boom are extended from the middle boom, the total length should be extended to about three times the length of the middle boom. The lift table can be lifted high.

In such a newly proposed aerial work platform, X
The lower boom and upper boom are configured to extend and retract one by one from the upper and lower open ends of the pair of middle booms that are shaped like a letter, and the lower boom is connected to the vehicle body side, and the upper boom is connected to the lifting platform by the side surface. The feature was that the structure was such that an X-shape was formed when viewed from above. With this structure, it is possible to lower the height position when folded like a scissor type, and since the tips of the lower and upper booms are connected with pins, it is possible to firmly move up and down against shaking and the like. Can be held, and is highly safe.

Also, since the lengths of the lower and upper booms can be made approximately equal to the length of the middle boom, respectively, the lifting platform can be raised to a higher position, and the lifting height of the lifting platform can be increased compared to the total length of the folded state. There have been many merits that can be set high.

However, in this configuration, the lower boom and the upper boom are inserted into the middle booms, so that the structure can be expanded and contracted in only three stages. Therefore, in order to increase the ascendable height of the lifting platform, the length of the middle boom may be set to be long. In this way, if the middle boom is lengthened, the lifting platform can be raised to a high position, but the overall length of the vehicle body that houses the middle boom must be lengthened, and the design of the vehicle body must be changed significantly. In this conventional aerial work vehicle, there has been a serious limitation that the lifting height of the lifting platform is determined by the length of the middle boom and the entire length of the vehicle body.

Therefore, there has been a demand for the development of an aerial work vehicle in which the length of the middle boom is the same as that of the conventional lifting mechanism, but the lifting platform can be lifted to a higher position.

[Problems to be Solved by the Invention]

The present invention provides an aerial work vehicle that overcomes the above-mentioned drawbacks. In the present invention, the lower intermediate boom, the lower boom, the upper intermediate boom, and the upper boom, which are capable of expanding and contracting in a plurality, respectively, are inserted into the upper and lower open ends of the central boom so as to be extendable and contractible, and these booms are connected by a connecting means such as a wire. The main point is the structure. With this structure, the amount of expansion and contraction of each of the four booms that expand and contract with respect to the central boom can be synchronized, which allows the lifting platform to be raised to a higher position compared to the conventional three-stage boom structure. It is possible to provide an aerial work vehicle capable of performing such work.

[Means for Solving the Problems]

The present invention relates to an aerial work vehicle including a movable vehicle body, a lift table that is located above the vehicle body and can be vertically moved up and down, and a lift mechanism that is interposed between the vehicle body and the lift table to lift the lift table. , A pair of X-shaped central booms that are rotatably connected to each other, a lower middle boom that is telescopically inserted in the longitudinal direction from each lower end opening of each central boom, and each lower middle Lower booms that are telescopically inserted into the lower end openings of the booms, and their lower ends are connected to the vehicle body, and upper middle parts that are slidably inserted into their upper end openings of each central boom along their length direction. Aerial work comprising a boom and upper booms slidably inserted in the length direction from the upper end openings of the respective upper intermediate booms, and the upper ends thereof are respectively connected to the lower surface of the lifting platform. The one that provides the car That.

[Action]

In the present invention, the lower intermediate boom, the lower boom, the upper intermediate boom, and the upper boom are housed in two stages from the openings at both ends of each central boom. Due to this structure, the boom extends in two stages from both ends of the central boom, and the total length can be extended to about five times that of the central boom. And since the pair of center booms are pivotally supported so that their centers become X-shaped,
When each boom extends, the center boom rotates about its center to lift the lifting platform. In this way, the central boom rotates in an X-shape and the total length extends in five steps, so that the lifting platform can increase its ascent limit height as compared with the conventional lifting mechanism capable of expanding and contracting in three steps.

〔Example〕

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

FIG. 1 is a side view showing a state in which the elevator is lowered to the lowest position in the present embodiment, FIG. 2 is a front view of the same, and FIG. 3 is a state in which the elevator is lifted to the maximum height position. It is a side view shown.

In the figure, reference numeral 1 is a vehicle body, and front and rear wheels 2 and 3 are pivotally supported on the front, rear, left and right of the vehicle body 1, and an elevating mechanism 4 is mounted on the upper surface of the vehicle body 1. An elevating table 5 is located on the upper surface of, and a handrail 6 is fixed around the elevating table 5. A kick mechanism 7 for initial lifting of the lifting mechanism 6 is attached to the center of the upper surface of the vehicle body 1.

This elevating mechanism 6 is composed of four sets of telescopic boom bodies 10, two telescopic boom bodies 10 in a set are arranged on both left and right sides, and the telescopic boom bodies 10 of each set are a central boom 11 and a lower intermediate boom. It comprises a lower boom 13, a lower boom 13, an upper middle boom 14, and an upper boom 15.

And, out of the telescopic boom body 10 of each set of two,
The insides of the pair of central booms 11 are pivotally connected to each other in an X shape so as to be rotatable. The lower intermediate boom 12 is inserted through the lower end opening of the central boom 11 so as to be able to extend and contract in the length direction of the central boom 11.
It is inserted into the lower end opening of 12 so that it can expand and contract along its length. A connecting piece 16 is fixed to the lower end of the lower boom 13, and the connecting piece 16 is rotatably connected to a fixed piece 17 fixed to the front and rear of the vehicle body 1 by a pin.

Further, the upper intermediate booms 14 are inserted into the upper end openings of the respective central booms 11 so as to be slidable along the length direction of the central booms 11, and the upper booms 14 are inserted into the upper end openings of the respective upper intermediate booms 14. Is inserted so that it can expand and contract along its length. A connecting piece 18 is fixed to the upper end of the upper boom 15, and the connecting piece 18 is rotatably connected to a fixed piece 19 fixed to the front and rear of the lower surface of the lifting table 5 by a pin.
The distance between the fixing pieces 17 and 17 and the distance between the fixing pieces 19 and 19 are set to the same length, and when the telescopic booms 10 rotate and extend to form an X-shape, respectively. The elevating table 5 can be raised while maintaining the vehicle body 1 and the elevating table 5 in parallel.

An operating mechanism 20 for extending and retracting the entire lifting mechanism 4 is attached between the fixed piece 17 and the lower intermediate boom 12, and the operating mechanism 20 is composed of a hydraulic cylinder and a guide mechanism. These structures will be described in detail later.

Next, FIG. 4, FIG. 5, FIG. 6, FIG. 7 and FIG. 8 will explain in detail the internal structure of the elevating mechanism 4, that is, the telescopic boom body 10, and the combination thereof.

Each of the central booms 11, the lower middle booms 12, the lower booms 13, the upper middle booms 14, and the upper booms 15 that constitute the telescopic boom body 10
Each has a slender shape in which a thin steel plate is bent and the inside has a hollow cross-section that is slightly square.The center boom 11 has a cross-section that is slightly enlarged in the lateral direction. A partition plate 25, which divides the interior into two spaces along its length, is fixed. The lower intermediate boom 12 is inserted into one of the spaces of the central boom 11 divided by the partition plate 25, and the lower intermediate boom 12 has a slightly hollow cross-sectional internal hollow structure. There is. The lower boom 13 is inserted inside the lower intermediate boom 12, and the cross section of the lower boom 13 has a hollow inner shape that is slightly square-shaped. Also,
An upper intermediate boom 14 is inserted in the other space, which is an internal space of the central boom 11 and is partitioned by a partition plate 25, and the upper intermediate boom 14 has a slightly R-shaped cross section and has an internal structure. It is hollow. The upper boom 15 is inserted inside the upper intermediate boom 14, and the upper boom 15
The cross-sectional shape is slightly square and the inside is hollow.

The telescopic boom bodies 10 assembled in this way are horizontally arranged so that they are parallel to each other, as shown in FIG. In this figure, four telescopic boom units 10 are arranged side by side, but there is a space between the insides of the center booms 11-B and 11-C, and there are spaces between the center booms 11-B and 11-C. A kick receiver 26 in the form of a pipe is interposed between the kick receiver 26 and the kick receiver 26 so as to come into contact with the upper end of the kick mechanism 7. Furthermore, reinforcing bars 27 and 28 are interposed between the upper and lower ends of the central booms 11-B and 11-C, respectively.
A ladder-shaped structure is formed by the central booms 11-B and 11-C, the kick receiver 26, and the reinforcing bars 27 and 28.

A bearing mechanism 29 for freely rotating the central booms 11-A and 11-B is interposed between the centers of the central booms 11-A and 11-B. The central booms 11-A and 11-B can rotate alternately. Similarly, the center booms 11-C and 11-D are rotatably connected to each other by the bearing mechanism 29.

Further, a reinforcing rod 30 is interposed between the lower intermediate booms 12 that extend and contract from the lower end openings of the central booms 11-B and 11-C, and from the upper end openings of the central booms 11-B and 11-C. A reinforcing rod 31 is interposed between the pair of upper intermediate booms 14 that expand and contract, and the lower intermediate boom 12 and the upper intermediate boom 14 can be slid in synchronization with each other by the reinforcing rods 30 and 31. . Further, between the center booms 11-A and 11-D disposed on both sides of the four telescopic boom bodies 10, the lower side of the center booms 11-B and 11-C is dipped. And reinforcing rod 32
Are connected. Further, a reinforcing rod 33 is connected between the upper ends of the central booms 11-A and 11-D so as to straddle the upper sides of the central booms 11-B and 11-C. For this reason, the central boom 11
-A and 11-D are assembled in a ladder shape with reinforcing rods 32 and 33 interposed at both ends, and the central boom 11-A, 11-D, reinforcing rod 32,
33 has a rigid structure as a whole. Next, a reinforcing rod 34 is interposed between the lower intermediate booms 12 extending and contracting from the central booms 11-A and 11-D so as to dive under the central booms 11-B and 11-C. The lower middle boom 12 is being reinforced. In addition, a reinforcing rod 35 is interposed between the upper intermediate booms 14 extending and contracting from the central booms 11-A and 11-D so as to straddle the lower sides of the central booms 11-B and 11-C. Both upper intermediate booms 14 are reinforced by the rods 35. The seventh
The drawing is a cross-sectional view taken along the line XX in FIG. 6, showing the relationship between the central booms 11-A, 11-B, 11-C, 11-D and the bearing mechanism 29.

Next, FIG. 8 is an exploded perspective view showing the structure of the bearing mechanism 29.

This bearing mechanism 29 is capable of rotating the two central booms 11-A and 11-B with respect to each other, and a ring-shaped bearing washer 40 is closely attached to the outer surface of the central boom 11-B. A circular guide groove 41 is formed on the inner peripheral wall of the bearing washer 40, and a screw hole 42 is opened around the bearing washer 40. The bearing washer 40 is arranged so that its central axis is on the same axis as the kick receiver 26, and is brought into close contact with the side surface of the central boom 11-B.
It is screwed by inserting it into 42.

A ring-shaped seat plate 44 is fixed to the center of the inner surface of the central boom 11-A, and a screw hole is provided around the seat plate 44.
45 is opened, and a sliding claw 46 that engages with the guide groove 41 is brought into close contact with the screw hole 45, and each sliding claw 46 is fixed to the seat plate 44 by a screw 47. This sliding claw
Since 46 is fitted to the peripheral wall of the guide groove 41 and then fixed by a screw 47, both are assembled so that they can rotate relative to each other.

Next, FIG. 9 shows the central boom of the telescopic boom unit 10.
Lower middle boom 12, lower boom 13, upper middle boom
14 shows a mechanism for synchronizing each of the upper boom 15 and the upper boom 15.

In this embodiment, the lower intermediate boom 12 that extends and contracts from the central boom 11
And the amount of expansion and contraction of the upper intermediate boom 14 must be the same, and the amount of expansion and contraction of the lower boom 13 extending from the lower intermediate boom 12 and the upper boom 15 extending from the upper intermediate boom 14 must be the same. That is, as shown in FIG. 3, this is an indispensable condition for vertically raising the elevating table 5 while maintaining it horizontally. In FIG. 9, one of the four telescopic boom units 10 is explained, and the same synchronizing mechanism is adopted for the structure of the other three telescopic boom units 10. There is. Further, FIG. 9 is shown to explain this synchronization mechanism, and note that the positional relationship between the lower boom 13 and the upper boom 15 is slightly different from the actual mechanism in the arrangement of each member. I want to be done.

Inside the upper part of the central boom 11, a pulley 50 is rotatably supported so as to be slightly horizontal, and a wire 51 for synchronization is wound around the pulley 50. One end of the wire 51 Is connected to the upper end of the lower intermediate boom 12, and the lower end of the wire 51 is connected to the lower end of the upper intermediate boom 14. This allows the lower middle boom 12 and the upper middle boom to
The body 14 and the central boom 11 will move with the same amount of expansion and contraction. A pulley 52 is rotatably supported on the upper end side surface of the lower intermediate boom 12, and the pulley 52 is
A wire 53 is wound around 52, and this wire 53
One end of is connected to the upper end of the lower boom 13 and the wire 53
The other end of is connected to the lower end of the central boom 11. further,
A pulley 54 is pivotally supported on the upper end side surface of the upper intermediate boom 14, and a wire 55 is wound around the pulley 54.
One end of the wire 55 is connected to the upper end of the central boom 11, and the other end of the wire 55 is connected to the lower end of the upper boom 15.

Then, FIG. 10 illustrates the structure of the actuating mechanism 20 in the present embodiment in detail. This actuating mechanism 20 is attached to each of the four telescopic boom bodies 10, but one of them is explained in FIG. 10, and the actuating mechanism 20 attached to another telescopic boom body 10 is All have the same configuration.

A pair of guide rails 60 are fixed to the lower surface of the central boom 11 along the length direction thereof at intervals, and both guide rails 60 each have a U-shaped cross section. The guide rails are located so that the internal spaces face each other, and extend over almost the entire length of the central boom 11.
60 is stuck. A roller 61 is movably inserted in the inner space of the guide rail 60, and the roller 61 is axially supported by a bearing plate 62. The bearing plate 62 is held in parallel with the central boom 11. It is fixed to the bar 63. The operating rod 63 has its lower end connected and fixed to the upper end of the guide body 64. The guide body 64 is formed in a U-shape as a whole, and an elongated space is formed inside the two members facing each other. Are linked to.

In this way, the guide body 64 and the operating rod 63 are attached to the lower intermediate boom 12
At the same time, it moves with respect to the central boom 11. The guide body 64 is formed in a U-shape as described above, and the guide groove 65 having a U-shaped cross section is formed on each of the inner surfaces facing each other, and the inside of the guide groove 65 is formed. Each roller 66 is inserted movably,
The roller 66 is supported by a shaft 67. The shaft 67 is pivotally supported by a pair of support plates 68, and a pulley 69 is pivotally supported between the support plates 68. This support plate 68 is fixed to the tip of the cylinder rod 72,
A hydraulic cylinder 71 for operating the cylinder rod 70 is located in the internal space of the guide body 64. The base of this hydraulic cylinder 71 is the fixed piece 17
And are rotatably connected by a pin. A wire 66 is wound around the pulley 69. One end of the wire 66 is connected to the lower end of the lower intermediate boom 12, and the other end of the wire 66 is connected to the upper end of the hydraulic cylinder 71.

Next, the operation of this embodiment will be described.

An engine (not shown) attached to the vehicle body 1 is operated, and a hydraulic pressure generation mechanism is operated by this engine to generate hydraulic pressure. This hydraulic pressure has four hydraulic cylinders 71-A, 71-B,
71-C, 71-D, respectively, and kick mechanism 7
Supplied to the hydraulic cylinder. Then, the hydraulic cylinders 71 extend in the lengthwise direction and act to push out the booms in the telescopic boom body 10, but when the lifting platform 5 is at the lowest position (state of FIG. 1). ) The booms are oriented parallel to each other in a straight line, no component force is generated in the direction of pivoting around the bearing mechanism 29 in the X-shape, and the lifting platform 5 does not rise. However, since the hydraulic pressure is also supplied to the kick mechanism 7 at the same time, the hydraulic cylinder of the kick mechanism 7 rises, and the kick receiver 26 is pushed upward by the kick mechanism 7, and the center boom body 11-A, 11-
B, 11-C and 11-D are lifted around the bearing mechanism 29 so as to be slightly X-shaped.

When the telescopic boom body 10 is lifted by the kick mechanism 7 to be in a slightly X-shaped state, the operation of each hydraulic cylinder 71 is started. First, when the hydraulic cylinder 71 is operated and the cylinder rod 70 is pushed out, the pulley 69 is pushed out upward together with the support plate 68, so that the wire 66 is pulled up. Since one end of the wire 66 is connected to the upper end of the hydraulic cylinder 71, this position does not change, and the wire 69 is pushed out by pushing out the pulley 69.
Operates so that the lower intermediate boom 12 can be lifted. Therefore, each intermediate boom 12 begins to extend so that the lower boom 13 is pulled out from the lower end thereof.

At this time, the guide body 64 together with the actuating rod 63 moves the lower intermediate boom 12
However, the distance between the guide body 64 and the central boom 11 will change. However, since the tip of the operating rod 63 moves in the guide rail 60 by the roller 61, the operating rod 63 and the guide body 64 are kept parallel to the lower intermediate boom 12, while the hydraulic cylinder 17 is kept parallel to the lower intermediate boom 12. It helps to maintain and move so that.

In this way, the lower intermediate boom 12 is pushed up by the hydraulic cylinder 71, and the lower boom 13 is pulled out from the lower end of the lower intermediate boom 12, whereby the respective parts of the telescopic boom body 10 are interlocked. This interlocking operation will be described with reference to FIG. 9. When the lower intermediate boom 12 is pushed up, the lower boom 13 is pulled out from the lower end of the lower intermediate boom 12, and a pulley 52 is pivotally supported at the upper end of the lower intermediate boom 12. Therefore, the position of the lower boom 13 does not change, while the pulley 52 moves up, the wire 53 is pulled up, and the central boom 11 is moved with respect to the lower intermediate boom 12. The distance that the central boom 11 moves with respect to the lower intermediate boom 12 is set to the same length as the length by which the lower boom 13 is pulled out from the lower intermediate boom 12. Therefore, when viewed from the central boom 11, the lower middle boom 12 and the lower boom 13 are relatively pulled out by the same length. When the lower intermediate boom 12 is pulled out from the central boom 11, the wire 51 is pulled out downward, the pulling out of the wire 51 is transmitted to the upper intermediate boom 14 via the pulley 50, and the upper intermediate boom 14 is placed at the upper end of the central boom 11. It will be pulled out from the opening. The upper middle boom 14 is the central boom.
The amount withdrawn with respect to 11 is the same as the amount with which the lower intermediate boom 12 is withdrawn from the central boom 11. When the upper intermediate boom 14 is further pulled out from the central boom 11, the pulley 54 axially supported by the upper intermediate boom 14 pulls up the wire 55. Since one side of this wire 55 is fixed to the central boom 11, this position does not change, and the upper boom 15 connected to the other end of the wire 55 does not move.
Will be drawn more. The amount of the upper boom 15 pulled out from the upper intermediate boom 14 is the same as the amount of the upper intermediate boom 14 pulled out from the central boom 11.

In this way, the wires 51, 53, 55 are interlocked with each other, and the lower middle boom 12, the lower boom 13, the upper middle boom 14, and the upper boom 15 are interlocked with respect to the central boom 11, and are drawn out. The amount by which the lower intermediate boom 12 and the upper intermediate boom 14 are pulled out with respect to the central boom 11 is the same, and the amount by which the lower boom 13 is pulled out by the lower intermediate boom 12 and the upper boom 15 by respect to the upper intermediate boom 14 are the same. The amount of pull-out is also the same, and the booms are synchronized with the same amount of movement.

This interlocking operation is performed by one telescopic boom body shown in FIG.
10 synchronization is described, but other telescopic boom bodies 10
The same synchronization operation can be performed for the same. Then, all the booms of the telescopic boom bodies 10 formed in the X-shape have the same movement amount, and the elevating mechanism 4 greatly expands while maintaining the X-shape and making the upper and lower shapes similar to each other intermittently. It will be. For this reason, the lift 5 is mounted on the vehicle body 1
Is lifted vertically upwards with respect to the lift table 5
Will be kept horizontal.

By this series of operations, by operating the hydraulic cylinder 71 to extend each boom of the telescopic boom body 10,
The aerial work vehicle can be changed from the state shown in FIG. 1 to the state shown in FIG. 3 and the lifting platform can be lifted up to a higher position, and the total length of the telescopic boom body 10 is about 10% smaller than that when it is contracted. It can be made 5 times longer. And
If the lift table 5 is lifted to a predetermined position, and if the hydraulic pressure supplied to the hydraulic cylinder 71 is stopped at that position, the lift table 5 will be held at that height position, and work at a high place must be performed. You can

In the extension operation of the pair of telescopic boom bodies 10, the two central booms 11-A, 11-B and the central booms 11-C, 11-D are relatively rotated, but the rotation is caused by the bearing mechanism 29. Done. In this bearing mechanism 29, the sliding claw 46 has a bearing washer.
Since it is engaged with the guide groove 41 of 40, the sliding claw 46 moves while sliding on the inner circumference of the guide groove 41. For this reason, the central booms 11-A and 11-B can be relatively rotated in the opposite directions without changing the left and right intervals, and both can be maintained in the X shape.

In addition, in order to lower the elevating table 5 after elevating the elevating table 5 to the high position as shown in FIG. 3, in reverse to the above, the supply direction of the hydraulic pressure supplied to the hydraulic cylinder 71 is reversed. , The lower intermediate boom 12 and the upper intermediate boom 14 are introduced toward the inside of the central boom 11, contrary to the above, by operating the cylinder rod 70 so as to retract toward the inside of the hydraulic cylinder 71. Inside the lower boom 13
The upper boom 15 is housed inside the upper intermediate boom 14, and the upper boom 15 can be housed in the upper intermediate boom 14 to reduce the total length of the telescopic boom 10. Can be made.

〔The invention's effect〕

Since the present invention is configured as described above, in the related art, the telescopic boom body can only be operated by extending and contracting in synchronization with three stages, but the telescopic boom body can be extended and retracted in five stages for synchronous operation. The lift can be lifted to a higher position. The height of the lifting mechanism in the reduced and folded state can be lowered, and the height can be reduced to a height similar to that of a conventional work platform for aerial work, which prevents workers from getting on and off and unloading materials. It will be extremely easy.

[Brief description of drawings]

FIG. 1 is a side view showing a state in which the lifting platform of an aerial work vehicle according to an embodiment of the present invention is lowered to the lowest position, FIG. 2 is a front view of the same as above, and FIG. FIG. 4 is a side view showing a state of being raised to a height position, FIG. 4 is a perspective view showing an outline of a telescopic mechanism, and FIG. 5 is a sectional view showing a structure of a central boom.
FIG. 7 is a plan view showing the arrangement of the central booms in the lifting mechanism, FIG. 7 is a sectional view taken along line XX in FIG. 6, and FIG.
FIG. 9 is an exploded perspective view showing the structure of the bearing mechanism, FIG. 9 is an explanatory view showing the synchronizing mechanism of the telescopic boom body, and FIG. 10 is a partially sectional perspective view showing the structure of the actuating mechanism. DESCRIPTION OF SYMBOLS 1 ... Car body, 4 ... Elevating mechanism, 5 ... Elevating table, 7 ... Kick mechanism, 10 ... Telescopic boom body, 11 ... Central boom, 12 ... Lower middle boom, 13 ... Lower boom, 14 ... Upper middle boom, 15 ... Upper Boom, 20 ... operating mechanism.

Claims (1)

[Claims] 1. An aerial work comprising a movable vehicle body, a lift table located above the vehicle body and capable of vertically moving up and down, and a lifting mechanism interposed between the vehicle body and the lift table for lifting the lift table. In the vehicle, a pair of central booms which are rotatably connected at their centers to form an X-shape, a lower intermediate boom which is telescopically inserted in the longitudinal direction from the lower end opening of each central boom, and A lower boom that is elastically inserted into the lower end opening of the lower intermediate boom and has its lower end connected to the vehicle body, and an upper boom that is slidably inserted along the lengthwise direction into the upper end opening of each central boom. An intermediate boom,
An aerial work vehicle comprising: an upper boom that is slidably inserted in the lengthwise direction from the upper end opening of each upper intermediate boom and that has its upper end connected to the lower surface of a lifting platform.