JPH03297797A - Kick mechanism for elevated place working vehicle - Google Patents

Abstract

PURPOSE:To lower the safety factor of a wire for elevation by lowering a boom load as the load is supported by a kick mechanism when it is detected that the central parts of a pair of intermediate stage booms pivotally supported in an X-shape to each other are brought into contact with the kick mechanism, secured to a car body, through contraction of booms. CONSTITUTION:Two-in-a-set expandable boom bodies 10 comprise central booms 11, lower intermediate booms 12, lower booms 13, upper intermediate booms 14, and upper booms 15. The inner central parts of the central booms 11 are rotatably intercoupled in an X-shape. The booms are inserted slidably over each other, a fixing piece 16 of a lower boom 13 is coupled to a fixing piece 17 of a car body 1, a working mechanism 20 is mounted between the fixing piece 17 and the lower intermediate boom 12, and the boom bodies 10 are telescoped by means of a working wire. A kick mechanism 7 is erected on a car body 1, and when the booms 10 are contracted and when a pivotally coupling part between the booms 11 is brought into contact with a kick support, an elevating platform is lowered as the load of an elevating platform 5 is received by the kick mechanism 7. Thus, the size of the working wire of a working mechanism 20 can be decreased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is useful for assembling buildings at high places, for work at high places such as painting, etc. Regarding aerial work vehicles used to load and unload materials that are no longer needed during work from a high position, in particular, wires that connect each boom when the platform is lowered,
This invention relates to a kick mechanism for an aerial work vehicle that can prevent chains and the like from breaking.

[Conventional technology]

Aerial work vehicles that raise and lower a lifting platform are often used for assembly, painting, and repairs at high places such as highways and building construction. They were tasked with loading and unloading the waste materials.

In this conventional lifting device, a pair of arms are pivoted at the center to make one set, and a pantograph-like extension mechanism is used in which multiple sets of arms are connected in the vertical direction (so-called scissor type). In order to increase the maximum lifting height of the lifting device, the length of each set of arms is increased, but this requires a greater number of connected arms. For this reason, if a lifting device is designed that can increase the height that can be raised, multiple sets of pantographs must be used, and the height of the lifting device when the pantographs are folded becomes high, making it difficult for workers to climb up and down the platform. The work of getting on and off the vehicle, loading and unloading materials was cumbersome.

In order to eliminate this drawback, various proposals have been made in the past, and for example, a structure as disclosed in US Pat. No. 3,820,631 has also been proposed. In this proposed structure, a lower boom and an upper boom, which can move in a straight line with respect to the middle boom, are inserted into the middle boom so that they can be inserted and removed, and the lower end of the lower boom is pivotally supported on the vehicle body side with a pin. The upper end of the upper boom is pivotally supported on the platform with pins and assembled to form an X-shape. This structure increases the length of the boom itself, so when it is folded,
The height of the platform can be lowered and the platform can be raised to a higher position.

However, in this invention, the mechanism that extends the lower and upper booms from the middle boom is composed of a screw and a female thread that engages with the screw, so the lower and upper booms extend and retract with respect to the middle boom at a slow speed, making it possible to quickly move the platform. It was impossible to respond. In addition, since the lower and upper booms are slid by a bevel gear installed in the center of each middle boom, the total length of the lower and upper booms is set to only about half the length of the middle boom. The structure was such that half the length of the middle boom could not be extended from the middle boom to the lower boom and then the upper boom, making it impossible to lift the platform higher.

Also, a structure has been proposed in which another boom is inserted into the boom and extended to lengthen the entire length of the boom itself. 1
For example, in Patent Publication No. 119556 of 1973, in Figure 4 of the middle cylinder of the drawing, the lower and upper booms of narrow diameter are inserted into the middle boom of thicker diameter, and the lower and upper booms inserted inside are inserted into the middle boom of thicker diameter. A structure has been proposed in which the overall length of the boom is increased by pulling it out from the middle boom, thereby raising the platform higher.

However, in this structure, there is no mechanism to synchronize the amount of expansion and contraction between the lower boom and the upper boom, which are pulled out from the middle boom, and each moves independently, and the amount of expansion and contraction is regulated by a link mechanism using bars. There is. For this reason, the platform could not be lifted vertically or horizontally, and could not be lifted to a desired vertical height position. Additionally, when the lower and upper booms housed in the middle boom extend and retract, a link mechanism formed by a bar is used to regulate the amount of movement of each, making it impossible to completely synchronize the amount of movement. Therefore, it was not possible to connect the lower and upper booms to the platform with pins, etc., and errors in synchronization had to be corrected using rollers that were in contact with the vehicle body and the platform. For this reason, the platform suffers from the accumulation of looseness due to the large number of pivot points in the link mechanism, as well as from the rolling motion caused by the rollers, resulting in a structure that is susceptible to sway and is extremely unstable as it easily sways due to wind and other factors. This caused workers to feel uneasy.

In order to eliminate these drawbacks, for example, a patent application was filed in 1930.
Proposal No. 41289 of 2006 has been made.

In this exit H, 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 pivoted to the middle boom. The structure is such that the direction of movement is changed by means of a changing means. In this configuration, when the lower boom is pulled out from the middle boom, the upper boom is pushed out from the middle and upper booms, and the amount of movement of the lower boom and upper boom is regulated by the linking means. The amount of movement will be the same,
A pair of middle booms pivoted at the center can rotate in an X-shape to push the platform vertically upward.

In this configuration, the lower and upper booms are housed within the middle boom, so when the lower and upper booms are extended from the middle boom, their total length will be approximately twice as long as the middle boom. This allows the platform to be lifted high.

In such a newly proposed aerial work vehicle,
The lower and upper booms are configured to extend and retract one pair at a time from the upper and lower open ends of the pair of middle booms, which are shaped like letters. The structure was characterized by an X-shape when viewed from above. With this structure, the height position when folded like a scissor type can be lowered, and the tips of the lower and upper booms are connected with pins, making the platform strong against shaking etc. can be maintained and is highly safe.

In addition, since the lengths of the lower and upper booms can be made almost equal to the length of the middle boom, the platform can be lifted to a higher position, and the height of lifting the platform can be reduced compared to the total length of the folded state. There were many benefits that could be set high.

However, in the configuration of this conventional X-type aerial work vehicle, it was necessary to connect the lower boom and the upper boom within each middle boom with a wire chain or the like in order to synchronize them. By connecting the upper end of the lower boom and the lower end of the upper boom with this wire chain, etc., the moving lengths of the lower boom and upper boom that are pulled out from the middle boom are synchronized, and the lifting mechanism is always in an X-shape. I was forced to keep it that way. Although synchronization using wires or chains is extremely simple in construction, a safe load must be set for tensile stress to prevent cutting accidents.

Setting this safe load did not pose much of a problem if the ratio of the height that the X-shaped lifting mechanism could lift from its folded state to its maximum height was small.

However, when the ratio of the height of the lifting platform to the length of the lifting mechanism in its folded state becomes large, setting the safe load has become an extremely important issue.

That is, when the lifting platform is raised at a high position, the angle at which the boom is depressed with respect to the horizontal is large, and the component force of the load applied to the lifting platform does not become very large. For this reason, 1. The tensile force applied to the wire connecting the lower boom and the upper boom does not become excessive. However, when the platform is in a lowered state, the angle of inclination at which the boom is depressed with respect to the horizontal becomes small, and the component force of the load applied to the platform becomes large. A component of this load is directly applied to the wires and chains used for synchronization, resulting in an extremely large tensile force. Therefore,
If the safety factor for the load applied to a wire chain, etc. is set small, an accident may occur in which the wire, chain, etc. breaks due to component force. When the wires, chains, etc. connecting the lower and upper booms broke, the platform suddenly descended, causing personal injury to the workers on board and damaging nearby structures.

Therefore, if a wire chain or the like with a low safety factor is used to synchronize the elevating platform A, there will be no problem when the elevating platform is raised high, but when the elevating platform is lowered, the component force of the load will increase. This was one of the causes of accidents in which wires, chains, etc. were broken and the platform suddenly descended.

In order to prevent such accidents from occurring, the safety factor should be increased and the safety load of wires, chains, etc. should be designed to be large. However, if wire chains, etc. are made thicker in order to increase the safe load, in extreme cases the wire becomes too thick, increases weight, and becomes less flexible, making it difficult to function smoothly as a lifting mechanism. It became a structure.

[Problem to be solved by the invention]

In the present invention, the kick mechanism used for the initial start-up of the elevating mechanism is used, and the load is auxiliary supported by this kick mechanism from the middle of the descent of the elevating platform. As a result, the lifting platform lowers and the boom angle of inclination becomes shallower.
When the load component becomes large, the kick mechanism can be used to disperse the load. Therefore, even if the lifting platform descends to the lowest position and the component force becomes extremely large, approaching infinity, the tensile force applied to the wire will not increase and is relatively low due to the design of the wire, chain, etc. To provide a kick mechanism for an aerial work vehicle that can set a safety factor.

[Means to try to solve the problem]

The present invention consists of a movable vehicle body, a lifting platform located above the vehicle body that can be raised and lowered up and down, a pair of middle booms pivoted in an X-shape so as to be rotatable at the center, and a length of each middle boom. a lower boom whose lower ends are connected to the car body; an upper boom which moves in the longitudinal direction of each intermediate boom and whose upper ends are connected to a lifting platform; It consists of a kick mechanism that is fixed to and pushes up the center of both middle booms, and a detection means that detects when both the middle boom and the kick mechanism have come into contact, and the lifting platform is lowered.
To provide a kick mechanism for an aerial work vehicle, characterized in that after a detection means detects that the middle boom has contacted the upper end of the kick mechanism, the kick mechanism lowers the middle boom while supporting its load. be.

[Effect]

In the present invention, a detection means is provided for detecting that the kick mechanism has come into contact with the middle boom. The kick mechanism can support the load of the lifting platform. Due to this load distribution,
No load is applied to wires, chains, etc. built into the elevating mechanism, and the entire component force generated from the load of the elevating platform is not held by wire chains, etc. Therefore, the safety factor set for wire chains etc. can be kept low. Therefore, the lower boom and the upper boom can be synchronized without increasing the thickness of the wire, chain 2, etc., or using an excessively large mechanism.

〔Example〕

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

Figure 1 is a side view showing the lifting platform lowered to the lowest position in this embodiment, Figure 2 is a front view of the same, and Figure 3 is the lifting platform raised to its maximum height. FIG.

In this figure, reference numeral 1 denotes a vehicle body, and 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, and a lifting mechanism 4 is mounted on the top surface of the vehicle body 1. A lifting platform 5 is located on the upper surface of the elevator, and a handrail 6 is fixed around the lifting platform 5. A kick mechanism 7 is attached to the center of the upper surface of the vehicle body 1 for initially lifting the elevating mechanism 6.

This elevating mechanism 6 consists of four sets of telescopic boom bodies 10, two sets of telescopic boom bodies 10 are arranged on both left and right sides, and each set of telescopic boom bodies 10 consists of a central boom 11, a lower middle boom 12, a lower boom 13, an upper intermediate boom 14, and an upper boom 15.

Of the telescopic boom bodies 1° of each set of two, the inner centers of the pair of central booms 11 are pivoted in an X-shape so as to be rotatable. A lower intermediate boom 12 is inserted into the lower end opening of the central boom 11 so that it can extend and contract in the length direction of the central boom 11, and a lower boom 13 is inserted into the lower end opening of the lower intermediate boom 12 so that it can extend and contract along its length. It has been inserted so that it can be inserted. A connecting piece 16 is fixed to the lower end of the lower boom 13, and this 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.

In addition, an upper intermediate boom 1 is provided at the upper end opening of each central boom 11.
4 are respectively inserted so as to be slidable along the length direction of the central boom 11, and an upper boom 14 is inserted into the upper end opening of each soil intermediate boom 14 so as to be extendable and retractable along the length direction. It is. A connecting piece 18 is fixed to the upper end of the upper boom 15, and this connecting piece 18 is rotatably connected to a fixed piece 19 fixed to the front and rear of the lower surface of the lifting platform 5 by means of a pin.

The distance between the fixed pieces 17 and 17 and the distance between the fixed pieces 19 and 19 are set to the same length, so that when each telescopic boom 10 rotates and extends to form an X-shape, This allows the lifting platform 5 to be raised while maintaining the vehicle body 1 and the lifting platform 5 parallel to each other.

An operating mechanism 20 is provided between the fixed piece 17 and the lower intermediate boom 12 to extend and retract the entire elevating mechanism 4.
is attached, and this operating mechanism 20 is constituted by a hydraulic cylinder and a guide mechanism, the structures of which will be explained in detail later.

Next, FIG. 4, FIG. 5, FIG. 6, FIG. 7, and FIG. 8 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 boom 11, lower intermediate boom 12, lower boom 13, upper intermediate boom 14, and upper boom 15 constituting this telescopic boom body 10 has an elongated shape with a hollow interior and a slightly rectangular cross section made by bending a thin steel plate. The cross section of the central boom 11 has a cross-sectional shape slightly expanded in the horizontal direction, and in the center there is a partition plate 25 that divides the interior into two spaces along its length. is fixed. A lower intermediate boom 2 is inserted into one space of the central boom 11 divided by this partition plate 25, and this lower intermediate boom 12
The cross-sectional shape is somewhat mouth-shaped with an internal hollow structure. A lower boom 13 is inserted into the lower intermediate boom 12, and the lower boom 13 has a hollow cross-sectional shape with a slightly cross-sectional shape. Further, an upper intermediate boom 14 is inserted into the other space, which is the internal space of the central boom 11 and is divided by the partition plate 25, and the upper intermediate boom 14 has a slightly cross-sectional shape. The inside is hollow. This upper intermediate boom 14
An upper boom 15 is inserted into the inside of the upper boom 15, and the upper boom 15 has a slightly cross-sectional shape and is hollow inside.

The telescopic boom body 10 assembled in this way is the sixth
As shown in the figure, they are arranged horizontally so that they are parallel to each other. In this figure, there are four telescopic booms 6 and 4 boom bodies 10 lined up, among which the central boom 11
-B and 11-C are spaced apart from each other, and a pipe-shaped kick receiver 26 is interposed between the centers of the central booms 11-B and 11-C. comes into contact with the upper end of the kick mechanism 7. Furthermore, reinforcing rods 27 and 28 are interposed between the upper and lower ends of the central booms 11-B and 11-C, respectively.
A ladder-like structure is formed by the reinforcing bars 27 and 28.

A mechanism 29 is interposed between the centers of the central booms 11-A and 11-B to allow the central booms 11-8 and 11-B to rotate freely relative to each other. 29 by central boom 11-8 and 11-
B can be rotated alternately. Similarly, the bearings are connected to the central booms 11-C and 11D by the mechanism 29.
are connected to each other so that they can rotate.

Further, a reinforcing rod 30 is interposed between the lower intermediate booms 12 that extend and retract from the lower 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 extend and retract from the upper end opening, and this reinforcing rod 30.31
This allows the lower intermediate boom 12 and the upper intermediate boom 14 to slide in synchronization. Furthermore, between the central booms 11-8 and 11-D, which are arranged on both sides of the four telescopic boom bodies 1O, the central booms 11-B and 11-C are arranged under the central booms 11-B and 11-C. Reinforcement rod 32
is connected. Furthermore, the central boom 118, 11-
A reinforcing rod 33 is connected between the upper ends of D so as to straddle the upper sides of the central booms 11-B and 11-C.

Therefore, the central booms 11-A, 11-D are assembled in a ladder shape with reinforcing rods 32.33 interposed at both ends, and the entire center booms 11-A, 11-D and the reinforcing rods 32.33 are assembled into a ladder shape. It has a rigid structure. Next, the lower intermediate boom 12 extends and contracts from the central booms 11-A and 11-D.
A reinforcing rod 34 is interposed between the central booms 11-B and 11-C so as to go under the bottom of the central booms 11-B and 11-C, and reinforces the intermediate boom 12 under rain.
A reinforcing rod 35 is interposed between the upper intermediate boom 14 that extends and retracts from 1-^ and 11-D so as to straddle the lower sides of the central booms 11-B and 11-C. The upper intermediate boom 14 is reinforced. In addition, FIG. 7 shows a cross section in the direction of arrows X-X in FIG. It is.

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

This bearing mechanism 29 has two central booms 11-A, 11
-B can be rotated with respect to each other, and a ring-shaped bearing washer 4 is installed on the outer surface of the central boom 11-B.
A circular guide groove 41 is formed on the inner circumferential wall of the bearing washer 40, and the bearing washer 40 has a circular guide groove 41 formed therein.
A screw hole 42 is opened around 0.

The bearing washer 40 is arranged so that its center axis is on the same axis as the kick receiver 26, and the center boom 1
It is brought into close contact with the side surface of 1-H, and is screwed by inserting a screw 43 into the screw hole 42.

A ring-shaped seat plate 44 is fixed to the center of the inner surface of the central boom 11-, and a screw hole 45 is opened around the seat plate 44. Sliding claws 46 that engage with the guide grooves 41 are brought into close contact with each other, and each sliding claw 46 is fixed to the seat plate 44 by screws 47, respectively. This sliding pawl 46 is connected to the guide groove 4.
After being fitted into the peripheral wall of 1, they are fixed with screws 47, so that they are assembled so that they can rotate relative to each other.

Next, FIG. 9 shows a mechanism for synchronizing each of the lower intermediate boom 12, lower boom 13, upper intermediate boom 14, and upper boom 15 with respect to the central boom 11 in the telescopic boom body 1o. .

In this embodiment, the lower intermediate boom 12 and the upper intermediate boom 14 that extend and contract from the center boom 11 must have the same amount of extension and contraction, and the lower boom 13 that extends from the lower intermediate boom 12 and the upper boom 15 that extends from the upper intermediate boom 14 must have the same amount of extension and contraction. The amount of expansion and contraction must be the same. That is, as shown in FIG. 3, this is an indispensable condition for vertically raising the elevator platform 5 while maintaining it horizontally. In FIG. 9, one of the four telescopic boom bodies 10 is explained, and the same synchronization mechanism is adopted for the structure of the other three telescopic boom bodies 1o. ing. Also, in Figure 9, “
This is shown to explain this synchronization mechanism, and it should be noted that the positional relationship of the lower boom 13 and upper boom 15 in the arrangement of each member is somewhat different from the actual mechanism.

A pulley 50 is rotatably supported inside the upper part of the central boom 11 so as to be slightly horizontal.A synchronization wire 51 is wound around this pulley 50, and one end of this wire 51 is wound around the pulley 50. is connected to the upper end of the lower intermediate boom 12, and the lower end of the wire 51 is connected to the upper end of the upper intermediate boom 1.
It is connected to the lower end of 4. As a result, the lower intermediate boom 12, the upper intermediate boom 14, and the central boom 11 move by the same amount of expansion and contraction, respectively. A boo IJ-52 is rotatably supported on the side surface of the upper end of the lower intermediate boom 12. A wire 53 is wound around the pulley 52, and one end of the wire 53 is attached to the upper end of the lower boom 13. The other end of the wire 53 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.

FIG. 10 explains in detail the structure of the actuation mechanism 20 in this embodiment. This operating mechanism 20 has four
The operating mechanism 20 is attached to the telescopic boom body 10 of the book, but only one of them is explained in FIG.
All have the same configuration.

A pair of guide rails 60 are fixed to the lower surface of the central boom 11 at intervals along its length,
Both guide rails 60 each have a U-shaped cross section, are positioned so that their internal spaces face each other, and are fixed to the center boom 11 over almost the entire length thereof. . A roller 61 is movably inserted into the inner space of this guide rail 60, and this roller 61 is pivotally supported by a bearing plate 62, and this bearing plate 62 is held parallel to the central boom 11. It is fixed to a rod 63. The lower end of the operating rod 63 is connected and fixed to the upper end of the guide body 64. The guide body 64 has a slightly U-shaped overall shape, and an elongated space is formed inside the two opposing members. is connected to.

In this way, the guide body 64 and the operating rod 63 move with respect to the central boom 11 together with the lower intermediate boom 12. As described above, this guide body 64 is formed in a U-shape, and guide grooves 65 each having a U-shaped cross section are formed on the opposing inner surfaces thereof. A roller 66 is movably inserted into each, and this roller 66 is supported by a shaft 67. This shaft 67 is supported by a pair of support plates 68, and a pulley 6 is provided between the support plates 68.
9 is pivoted. This support plate 68 is fixed to the tip of a cylinder rod 72, and a hydraulic cylinder 71 for operating this cylinder rod 70 is located in the internal space of this guide body 643. The base of this hydraulic cylinder 71 is rotatably connected to the fixed piece 17 by a pin. A wire 66 is wound around the pulley 69, and one end of this wire 66 is connected to the lower end of the lower intermediate boom 12.
The other end is connected to the upper end of the hydraulic cylinder 71.

Next, FIG. 11 explains the configuration of the kick mechanism 7 in detail.

This kick mechanism 7 includes a plurality of cylinder rods 75.7.
It is a hydraulic cylinder that expands and contracts in three stages by combining 6.77 in the shape of a hanging bamboo. A kicking body 78 opening upward in a 7-shape is fixed to the upper end of the cylinder rod 77. The kicking body 78 comes into contact with the outer periphery of the kick receiver 26 and can lift the kick receiver 26. The bottom portion of the kicking body 78, which is shaped like a 7, has the outer periphery of the kick receiver 26. A limit switch 79 is fixed for contacting with and detecting its position.

Next, FIG. 12 shows a part of the hydraulic control circuit 4 in this embodiment. In this embodiment, the lifting platform 5
Only the circuit part for lifting the machine is explained.

A suction side of a hydraulic pump 81 driven by an engine 80 is connected to an oil tank 82 that stores pressure oil. On the discharge side of this hydraulic pump 81, solenoid valves 82 and 83 are provided.
are connected to each other, and at the same time, these solenoid valves 82.
A return oil path 83 is connected to the oil tank 82 . This solenoid valve 83 has the hydraulic cylinder 71-^,
71-B are connected in series, and the solenoid valve 84 is connected to the kick mechanism 7.

These two solenoid valves 83 and 84 can be switched to neutral, tangential, and reverse tangential directions, respectively.
The solenoid valve 84 is provided with a coil L, and the solenoid valve 84 is provided with coils M and N.

Next, FIG. 13 shows the electric control circuit in this embodiment.

A control device (not shown) is attached to the lifting platform 5, and this control device is provided with a control switch 86 for raising and lowering the lifting platform when operated by a worker. This control switch 86 includes a contact 87 for controlling the ascending operation and a contact 88 for controlling the descending operation. A relay 89 is connected to the contact 87, and a relay 90 is connected to the contact 88. ing. A coil K is connected in series to a normally open contact 91 controlled by a relay 89, and a coil L is connected in series to a normally open contact 92 controlled by a relay 90. And the limit switch 7
9 is open when not in contact with the kick receiver 26, and a normally open contact 93 closed by the relay 89 and a coil M are connected in series to this limit switch 79. Furthermore, the limit switch 79 has a coil 9
A normally open contact 94, which is closed by 0, and a coil N are connected in series.

Next, the operation of this embodiment will be explained.

The engine 80 attached to the vehicle body 1 is operated and the hydraulic pop 81 is driven by the engine 80, so that the hydraulic pump 81 sucks up pressure oil from the oil tank 82 and supplies it to the electromagnetic valves 83 and 84. With this operation, the aerial work vehicle stands by for control of each part.

[Ascending the platform]

The state in which the lifting platform 5 has been lowered to the lowest position is the state shown in FIGS. 1 and 2. A case in which the lifting platform 5 is lifted from this lowest position will be explained.

In this state, the kick receiver 26 is in contact with the kick body 78, and the limit switch 79 is in contact with the outer periphery of the kick receiver 26, so the limit switch 79 is closed.

In this state, when the control switch 86 is operated to close the contact 87 for lifting, the relay 89 is activated and the normally open contact 9
1.93 is closed. Then, current flows through the coil and M, respectively, connecting the solenoid valves 83 and 84 in the positive direction. For this reason, four hydraulic cylinders 71-8, 71
-B, 7l-C171-D are each supplied with hydraulic pressure, and the kick mechanism 7 is also supplied with hydraulic pressure. Then, each hydraulic cylinder 71 extends in its length direction and acts to push out each boom in the telescopic boom body 10. However, when the elevator platform 5 is at the lowest position, the first
(state shown in the figure), each boom 7 is oriented parallel to each other in a straight line, and the bearing mechanism 2
No component force is generated in the direction of rotation in an X-shape around center 9, and the lifting platform 5 does not rise. However, the kick mechanism 7
Since hydraulic pressure is also supplied from the solenoid valve 84 at the same time,
Cylinder rod 75.76.77 of this kick mechanism 7
extend upward, and the kicking body 78 receives the kick receiver 2.
Push 6 upwards.

Therefore, the central boom body 11-^, 71-B, 7l-
C171-D is lifted around the bearing mechanism 29 in a slightly X-shape.

When the telescopic boom body 10 is lifted up by this kick mechanism 7 into a slightly X-shaped state, each hydraulic cylinder 7
1 is started. First, the hydraulic cylinder 71
When the cylinder rod 70 is pushed out by actuation, the pulley 69 is pushed upward together with the support plate 68, and acts to pull up the wire 66. Since one end of the wire 66 is connected to the upper end of the hydraulic cylinder 71, this position does not change, and when the pulley 69 is pushed out, the wire 66 operates to pull up the lower intermediate boom 12.

8 For this reason, each intermediate boom 12 is connected to the lower boom 1 from its lower end.
Start stretching by pulling out 3.

At this time, the guide body 64 moves with the lower intermediate boom 12 together with the operating rod 63, but the distance between the guide body 64 and the central boom 11 changes. However, since the tip of the actuating rod 63 moves within the guide rail 60 by the rollers 61, the actuating rod 63 and the guide body 64 are connected to the hydraulic cylinder 1 while maintaining parallel to the lower intermediate boom 12.
7 is maintained parallel to the lower intermediate boom 12 to assist in its movement.

In this way, the lower intermediate boom 12 is operated by the hydraulic cylinder 71.
is pushed up and the lower boom 13 is pulled out from the lower end of the lower intermediate boom 12, so that each part of the telescopic boom body 10 is interlocked. This interlocking operation is explained in the ninth
To explain with a diagram, 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. Since the pulley 52 is pivotally supported at the upper end of the lower intermediate boom 12, the lower intermediate boom 13 is pulled out from the lower end of the lower intermediate boom 12. Since the pulley 52 is raised, the wire 53 is pulled up, causing the central boom 11 to move relative to the lower intermediate boom 12, while the position of the central boom 13 remains unchanged. The distance that the central boom 11 moves relative to the lower intermediate boom 12 is set to be the same length as the length that the lower boom 13 is pulled out from the lower intermediate boom 12. For this reason, the central boom 11
When viewed from above, the lower intermediate 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 center boom 11, the wire 51 is pulled out downward, and the drawing of the wire 51 is transmitted to the upper intermediate boom 14 via the pulley 50.
It will be pulled out from the upper end opening.

The amount by which the upper intermediate boom 14 is pulled out from the center boom 11 is the same as the amount by which the lower intermediate boom 12 is pulled out from the center boom 11. When the upper intermediate boom 14 is further pulled out from the central boom 11, the pulley 54, which is pivotally supported by the upper intermediate boom 14, pulls up the wire 55. Since one end of the wire 55 is fixed to the middle boom 11, this position does not change, and the upper boom 15 connected to the other end of the wire 55 is pulled out from the upper middle boom 14. The amount by which the upper boom 15 is pulled out relative to the upper intermediate boom 14 is the same as the amount by which the upper intermediate boom 14 is pulled out from the center boom 11.

In this way, each wire 51, 53, 55 is linked, and the lower intermediate boom 12, lower boom 13, upper intermediate boom 14, and upper boom 15 are respectively pulled out in conjunction with the central boom 11. 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 furthermore, the lower intermediate boom 13 is pulled out by the lower intermediate boom 12.
The amount by which the upper boom L5 is pulled out relative to the upper intermediate boom 14 is also the same, and each boom is synchronized with the same movement amount.

Although this interlocking operation is explained for the synchronization of one telescopic boom body 10 shown in FIG. 9, the same synchronized operation can be performed for other telescopic boom bodies 10 as well.

Then, the amount of movement of all the booms of each telescopic boom body 10 formed in an X-shape becomes the same, and the lifting mechanism 4 expands greatly while maintaining the X-shape while making its upper and lower shapes similar and intermittent. I will do it. Therefore, the elevator platform 5 is lifted vertically upward relative to the vehicle body 1, and the elevator platform 5 is maintained horizontally.

Through this series of operations, the hydraulic cylinder 71 is actuated to extend each boom of the telescopic boom body 10, thereby changing the aerial work vehicle from the state shown in FIG. 1 to the state shown in FIG. The total length of the telescopic boom body 10 can be made to be approximately five times longer than the length when it is in the contracted state.Then, the lifting platform 5 can be raised to a predetermined position. Once lifted, if the hydraulic pressure supplied to the hydraulic cylinder 71 is stopped at that position, the lifting platform 5 will be held at that height position, making it possible to work at high places.

In the extension operation of this pair of telescopic boom bodies 10, the two central booms 11-A, 11-B and the central boom 11-
c and 11-D will rotate relative to each other, and this rotation is performed by the bearing mechanism 29. This bearing is mechanism 2
9, the sliding claw 46 is engaged with the guide groove 41 of the bearing washer 40, so the sliding claw 46 moves while sliding on the inner periphery of the guide groove 41. For this reason, the central boom 11
-A and 11-B can be relatively rotated in opposite directions without changing the left and right spacing, and both can be maintained in an X-shape.

Then, as the bearing mechanism 29 is raised by each hydraulic cylinder 71, the kick receiver 26 is raised by itself and separated from the upper surface of the kick body 78, and the limit switch 79 is opened. Therefore, no current flows through the coil M, and the solenoid valve 84 is in a neutral state. After this, both the lifting platform 5 and the bearing mechanism 29 continue to move up as described above, but each cylinder rod 75, 76, 77 of the kick mechanism 7
remains at its maximum length.

[When lowering the lifting platform]

As described above, after the lifting platform 5 has been raised to the high position shown in FIGS. 1 to 3, it is necessary for the operator to lower the lifting platform 5. The operation in this case will be explained.

First, a worker on board the lifting platform 5 closes the contact 88 of the control switch 86 . Then, current flows through the relay 90 and the normally open contacts 92 and 94 are closed. Therefore, current flows through the coil, but no current flows through the coil N because the limit switch 79 is open. When current flows through this coil, only the solenoid valve 83 is connected in the opposite direction, and the pressure oil from the hydraulic pump 81 is supplied to each hydraulic cylinder 71 in the opposite direction. Therefore, the length of each hydraulic cylinder 71 is reduced, and the cylinder rod is operated to be drawn inward of the hydraulic cylinder 71. Then, contrary to the above, the central boom 11
The intermediate boom I2 and the upper intermediate boom I4 slide toward the inside of the lower intermediate boom 12, and the lower boom 1 slides toward the inside of the lower intermediate boom 12.
3 slides, the upper boom 15 slides toward the inside of the upper intermediate boom 14, and the overall length of the telescopic boom 10 is reduced. This action is the opposite of the above,
The elevator platform 5 will gradually descend.

The central boom 11 is always rotated by the bearing mechanism 29.
It is supported by a shaft in a letter-shaped manner and descends while rotating around a bearing mechanism 29. When the kick receiver 26 of the bearing mechanism 29 descends and contacts the kick body 78, the kick receiver 26 is supported by the kick body 78. At the same time, the limit switch 79 comes into contact with the kick receiver 26, causing the limit switch 79 to close, causing current to flow through the coil N via the normally open contact 94, which is already closed. From this, the solenoid valve 84 has a coil N
are connected in the opposite direction, and the kick mechanism 7 is supplied with hydraulic pressure in the opposite direction from the hydraulic pump 81.

Then, the kick body 78 comes into contact with the kick receiver 26, and the load of the lifting platform 5 is supported via the kick body 78, and is gradually lowered. In other words, the load from the lifting platform 5 has been received by each hydraulic cylinder 71, but
Due to the reverse connection of the electromagnetic valve 84, part of the load is received by the kicking body 78, and part of the load is supported by the kicking mechanism 77 gradually contracting. This means that the kick mechanism 7 supports part of the load supported by each hydraulic cylinder 71, and the tensile force of the wire 5-53.55 actuated by the hydraulic cylinder 71 is reduced. Therefore, the inclination angle of the central boom 11 with respect to the vehicle body 1 becomes shallower, and the lifting platform 5
Even if the component force of the load applied from the lifting platform 5 increases, the component force from the lifting platform 5 distributed to the wires 53, 55 does not increase.

Next, another embodiment of the present invention will be described.

In this embodiment, parts of the hydraulic control circuit and the electric control circuit are changed, and mechanisms common to those of the first embodiment are given the same numbers and explanations thereof are omitted.

FIG. 14 shows a hydraulic control circuit of another embodiment.

The above-mentioned solenoid valve 83 and hydraulic cylinder 71-8, 71-B
Throttle valves 95 and 96 are interposed between the two.

Electromagnetic valves 97 and 98 for disconnecting the hydraulic circuit are connected in parallel to both sides of each throttle valve 95 and 96.

The electromagnetic valve 97 is provided with a coil Q for cutting off the oil passage, and the electromagnetic valve 98 is connected with a coil R for cutting off the oil passage.

Next, FIG. 15 shows an electric control circuit of another embodiment, in which coils Q and R are connected in parallel with the coil N, respectively.

In this embodiment, when the lifting platform 5 can be lifted, it is started by closing the contact 87 of the control switch 86, as in the first embodiment described above. When the contact 87 is closed, the relay 89 is activated, the normally open contact 91.93 is closed, current flows through the coil, and the solenoid valve 83.84 is connected to the positive side.
Pressure oil is supplied to the kick mechanism 7 and the hydraulic cylinder 71, and the lifting platform 5 is raised. The subsequent operations are the same as in the first embodiment.

However, when the elevator platform 5 descends, the operation is somewhat different from that of the first embodiment described above.

That is, when the lifting platform 5 is at a high position before the kick receiver 26 comes into contact with the kicking body 78, the limit switch 79 is open, so the lifting platform 5 is lowered by the amount of contraction of the hydraulic cylinder 71.

When the kick receiver 26 comes into contact with the kick body 78 due to the lowering of the lifting platform 5 and the bearing mechanism 29, the limit switch 79 is closed, and each Coil N, Q
, a current flows through R. Then, the solenoid valve 84 is in reverse contact, and pressurized oil from the hydraulic pump 81 is applied to the kick mechanism 7 in the opposite direction, so that the cylinder rods 75, 76, 77 of the kick mechanism 7
gradually lower. With this operation, the kick body 78 is gradually lowered while supporting the load from the kick receiver 26.

At this time, current flows through coils Q and R at the same time, so solenoid valves 97 and 98 are closed, and solenoid valve 83 and hydraulic cylinder 7
The direct connection between 1-8 and 71-8 is stopped. For this reason,
Hydraulic cylinders 71-^ and 71-B have throttle valves 95.9
6, the reversed hydraulic pressure is supplied to each hydraulic cylinder 71-A, 71-B at a slow speed. Therefore, the hydraulic cylinders 71-^ and 71-B contract at a slow speed, and the kick mechanism 7 descends at a faster speed, so that the hydraulic cylinders 71-^ and 71-B operate in accordance with the operation of the kick mechanism 7.

Therefore, the wires 53 and 55 being pulled by each hydraulic cylinder 71 are always in a state where a tensile force is applied, and are driven by the kick mechanism 7 while having a certain amount of tensile force. In this operation, unlike the first embodiment, the solenoid valve 83 is connected to the hydraulic cylinders 71-A and 71-A.
1-B is directly connected to continue the contraction operation, and if there is a phenomenon in which the contraction speed of the hydraulic cylinder 71 becomes faster than the contraction speed of the kick mechanism 7, each wire 53, 55 becomes slack, and the inside of the telescopic boom body 10 The wires 53,55 will hang down.

Depending on the slack of the wires 53, 55, it is possible to prevent the hook from falling off the rotating pulley 50, 52, 54, 69, and the phenomenon that the lifting operation becomes impossible again.

In this embodiment, in order to lift the lifting platform 5, a lower intermediate boom 12, a lower boom 13, an upper intermediate boom 14, and an upper boom 15 are slidably inserted into the central boom 11 in three stages. Although the explanation is based on the configuration of the telescopic boom body 10 that expands and contracts, the present invention is not limited to this embodiment. It goes without saying that even a telescoping boom body that retracts has the same effect.69 [Effects of the Invention] Since the present invention is configured as described above, conventionally, when lowering a lifting platform, there is Although it was lowered by the reduction force of the installed hydraulic cylinder, the load of the lifting platform can be borne by a kick mechanism below a predetermined height. As a result, even if the inclination angle of the telescopic boom body becomes shallower and the component force of the load from the lifting platform becomes larger, most of the component force is supported by the kick mechanism, and the upper boom installed inside the telescopic boom body This prevents large loads from being applied to wire chains, etc. used to synchronize the lower boom and the lower boom.

Therefore, damage accidents such as wire breaks can be prevented, and the safety factor of the wire chain can be kept low, so the weight of the entire device can be reduced.

[Brief explanation of drawings]

Fig. 1 is a side view showing the lift platform of an aerial work vehicle according to an embodiment of the present invention lowered to the lowest position, Fig. 2 is a front view of the same, and Fig. 3 is a side view showing the platform lowered to the lowest position. Fig. 4 is a perspective view showing the outline of the telescoping mechanism; Fig. 5 is a cross-sectional view showing the structure of the central boom; Fig. 6 is a cross-sectional view of each central boom in the elevating mechanism. A plan view showing the arrangement of the boom, Figure 7 is x-x in Figure 6.
8 is an exploded perspective view showing the configuration of the bearing mechanism; FIG. 9 is an explanatory view showing the synchronization mechanism of the telescopic boom body;
Fig. 0 is a partially sectional perspective view showing the configuration of the operating mechanism, Fig. 11 is an enlarged perspective view showing the relationship between the kick mechanism and the kick receiver of this embodiment, and Fig. 12 shows the hydraulic control circuit of the telescoping mechanism. Fig. 13 is an electric circuit diagram for controlling a solenoid valve in a hydraulic circuit, Fig. 14 is a hydraulic circuit diagram showing another embodiment of the present invention, and Fig. 15 is an electromagnetic circuit diagram of a hydraulic circuit in another embodiment of the present invention. FIG. 3 is an electrical circuit diagram for controlling the valve. 1... Vehicle body, 4... Lifting mechanism, 5... Lifting platform, 7
...Kick mechanism, 10... Telescopic boom body, 11...
・Central boom, 12...Lower intermediate boom, 13...Lower boom, 14...Upper intermediate boom, 15...Upper boom, 26...Kick receiver, 78...Kick body, 79...
...Limit switch, 83.84...Solenoid valve.

Claims (1)

[Scope of Claims] A movable vehicle body, a lifting platform located above the vehicle body that can be raised and lowered, a pair of middle booms pivoted in an X-shape so as to be rotatable at the center, and a pair of middle booms for each middle boom. A lower boom that moves in the length direction and whose lower end is connected to the vehicle body, an upper boom that moves in the length direction of each middle boom and whose upper end is connected to the lifting platform, and the vehicle body. It consists of a kick mechanism that is fixed at the top and pushes up the center of both middle booms, and a detection means that detects when both the middle boom and the kick mechanism have contacted each other. A kick mechanism for an aerial work vehicle, characterized in that after a detection means detects contact with a boom, the kick mechanism lowers the middle boom while supporting its load.