JPH0776079B2 - Aerial work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to lifting workers or materials upward for work in high places such as assembly and painting of buildings at high places, and construction sites. Regarding aerial work vehicles used for unloading unnecessary materials from a high position,
The present invention relates to an aerial work vehicle, wherein an entire lifting mechanism for lifting a lifting platform is formed with a structure similar to a hydraulic cylinder.

[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 it is unnecessary to put workers, materials, etc. on the elevator to lift them. I was working on loading and unloading the materials.

In this conventional aerial work vehicle, a pantograph-like telescopic 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 this mechanism, in order to increase the maximum lifting height of the lifting platform, it is necessary to increase the length of the arms of each group or increase the number of arms to be connected. For this reason, if it is necessary to use a large number of pantographs when designing an elevating mechanism that can increase the ascending height, the height of the elevating mechanism in the folded state of the pantograph becomes high, and the worker gets on and off the platform The work of loading, loading and unloading materials was troublesome.

In order to eliminate such drawbacks, various proposals have hitherto been made, for example, a structure as disclosed in US Pat. No. 3,820,631 has 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 into and removed from the middle boom, and the lower boom is pivotally supported by a pin on the vehicle body side at the lower end. The upper boom is assembled so that the upper end of the upper boom is pivotally supported on the platform with a pin to form an X shape. In this structure, since the boom itself is long, the height of the platform can be reduced 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 expansion and contraction moving speed of the lower boom and the upper boom with respect to the middle boom is slow, and the platform can be quickly moved. It was something I couldn't respond to. 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 be set to about half the length of the middle boom. Without being able to extend and retract from the middle boom, the lower and upper booms could only act for half the length of 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 contract 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 thin multi-stage boom and an upper boom are inserted into a thick middle boom, and the boom inserted inside is pulled out from the middle boom to lengthen the boom length, thereby increasing the platform length. Is configured to be lifted high. However, in this 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 link mechanism by the bar. . For this reason, the platform cannot be lifted in the vertical direction while being held horizontally, and cannot be lifted to the target vertical height position.

Also, when the lower and upper booms housed in the middle boom expand and contract, their movements are regulated by the link mechanism formed by the bar, so perfect synchronization of the movements of the two is impossible. For this reason, the lower boom cannot be connected to the vehicle body and the upper boom platform by pins or the like, and the error that cannot be synchronized has to be made by the rollers that are in contact with the vehicle body and the platform. For this reason, the platform is subject to rolling by the link mechanism as it is, so that it has a structure that easily shakes, easily swings due to wind or the like, and is extremely unstable, which gives anxiety to workers.

Further, in FIG. 4 of the drawing, the X-shaped middle boom is rotated by a hydraulic cylinder attached to the outside, and the structure in which the lower boom and the upper boom are pulled out by the rotation of this middle boom is shown. Has been done.
The upper and lower booms are regulated in their withdrawal amounts by the link mechanism, but the operating force of the hydraulic cylinders is the upper one when the hydraulic cylinders that act linearly on the upper and lower booms are 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, the maximum extension length of the entire boom to be extended cannot be extremely lengthened.

Next, as a configuration for extending the entire length of the folded boom in the lengthwise direction, for example, a configuration such as Japanese Patent Application No. 18492/1972 is 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 beams are slidably inserted into the respective storage chambers. A working cylinder is housed in one of the housing chambers, and both outrigger beams are connected by a rope.

In this configuration, by activating the actuating cylinder, the outrigger beams appear and disappear from the outrigger box, and both outrigger beams can move in opposite directions. Therefore, each outrigger beam drawn out from the outrigger box can be extended to about the length of the outrigger box, which is effective for extending the outrigger beam out of the outrigger box.

However, this structure shows a structure 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. It was a thing. In addition, in the drawings described in this publication, both ends of both outrigger beams are not connected to any structure, and a configuration is shown in which the outrigger beams are simply expanded and contracted in the left and right horizontal directions. It's just that.

From such a point of view, a number of lifting mechanisms have been devised which are configured so that a plurality of booms can be telescopically inserted into the arm and one arm can be extended in the length direction. For example, Japanese Patent Application No. 134487/1983, Japanese Patent Application No. 191065/1981 and the like can be mentioned.

With these new lifting mechanisms, three-tiered booms extend in their respective lengths, and the middle boom that is assembled into an X-shape meets at the center, resulting in an X-shaped body and lifting platform when viewed from the side. It is configured so that it can be raised and lowered even at a high position. Further, since the respective tips of the lower boom and the upper boom are connected to the vehicle body or the lifting platform by pins, there is little rattling and a strong force against shaking can be exerted.

In these newly proposed lifting mechanisms using 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, a hydraulic cylinder interposed between the vehicle body and the center of the middle boom is used. There is a configuration in which the middle boom itself is lifted or the lower boom or the upper boom is pushed out by a hydraulic cylinder inserted in the middle boom to extend the boom.

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 tuning mechanism must be provided with a chain or wire, which complicates the configuration. At the same time, there is a drawback that the lifting mechanism itself is heavy.

[Problems to be Solved by the Invention]

The present invention provides an aerial work vehicle that overcomes the above-mentioned drawbacks.The middle boom itself of a conventional lifting mechanism is configured as a hydraulic cylinder, and a lower rod and a lower rod are respectively provided from the upper end and the lower end of the cylinder body in the center. It is an object of the present invention to provide an elevating mechanism having a simple structure by inserting the upper rods in a retractable manner and eliminating the tuning mechanism and the hydraulic cylinder.

[Means for Solving the Problems]

The present invention provides an X-shaped center of a movable vehicle body, a lift table located above the vehicle body and capable of moving up and down, and a pair of hydraulic expansion / contraction mechanisms interposed between the vehicle body and the lift table and capable of expanding and contracting in three stages. In an aerial work vehicle having a lifting mechanism that is rotatably combined, a pair of cylinders whose center is rotatably connected in an X shape is opened at both ends, and an upper rod can be slid from one of the opened ends. The lower rods are slidably inserted from the other open ends, the upper ends of the pair of upper rods are connected to the lower surface of the lift table at intervals, and the lower ends of the pair of lower rods are connected to the upper surface of the vehicle body. Connected at intervals, forming a closed space in the cylinder body where hydraulic pressure is supplied to each of the lower rod and the upper rod,
(EN) Provided is an aerial work vehicle characterized in that the hydraulic area acting on the lower rod and the hydraulic area acting on the upper rod are made substantially equal.

Preferably, the present invention provides an aerial work vehicle characterized in that the cylinder body, the upper rod, and the lower rod are formed in a cylindrical shape.

Further, according to the present invention, a movable vehicle body, an elevating table which is located above the vehicle body and can be vertically moved up and down, and a center of a pair of hydraulic expansion / contraction mechanisms which are interposed between the vehicle body and the elevating table and can expand and contract in three stages are provided. In an aerial work vehicle having an elevating mechanism rotatably combined in an X shape, a pair of hydraulic expansion / contraction mechanisms has a pair of cylinder bodies whose center is rotatably connected in an X shape, and one opening of each of the cylinder bodies. It consists of an upper rod slidably inserted from the end and a lower rod slidably inserted from the other open end of the cylinder body.
Each cylinder body has a cylindrical outer case with both ends open, a cylindrical inner case with both ends open and its outer diameter smaller than the inner diameter of the outer case, and both ends have its outer diameter Is composed of a cylindrical inner case having a diameter smaller than the inner diameter of the outer case, the upper case of the outer case and the upper case of the middle case are hermetically coupled, the lower ends of the inner case and the inner case are hermetically coupled, and Insert the cylindrical lower rod from the lower end into the gap formed by the outer and middle cases in a slidable and airtight manner, and insert the cylindrical upper rod into the gap formed by the inner and inner cases from the upper end of the outer case. An annular hydraulic cross section that is slidably and airtightly inserted and that is formed by the outer case and middle case and acts on the lower rod, and an annular hydraulic cross section that is formed by the middle case and inner case and acts on the upper rod. To be approximately equal There is provided a Aerial, characterized in that the set.

Further, the present invention provides a movable vehicle body, a lift table located above the vehicle body and capable of moving up and down, and a center of a pair of hydraulic expansion and contraction mechanisms interposed between the vehicle body and the lift table and capable of expanding and contracting in three stages. In an aerial work vehicle having an elevating mechanism rotatably combined in an X shape, a pair of hydraulic expansion / contraction mechanisms has a pair of cylinder bodies whose center is rotatably connected in an X shape, and one opening of each of the cylinder bodies. It consists of an upper rod slidably inserted from the end and a lower rod slidably inserted from the other open end of the cylinder body.
Each cylinder body has a cylindrical outer case with both ends open, a cylindrical inner case with both ends open and its outer diameter smaller than the inner diameter of the outer case, and both ends have its outer diameter Is composed of a cylindrical inner case having a diameter smaller than the inner diameter of the outer case, the upper case of the outer case and the upper case of the middle case are hermetically coupled, the lower ends of the inner case and the inner case are hermetically coupled, and Insert the cylindrical lower rod from the lower end into the gap formed by the outer and middle cases in a slidable and airtight manner, and insert the cylindrical upper rod into the gap formed by the inner and inner cases from the upper end of the outer case. An annular hydraulic cross section that is slidably and airtightly inserted and that is formed by the outer case and middle case and acts on the lower rod, and an annular hydraulic cross section that is formed by the middle case and inner case and acts on the upper rod. To be approximately equal The lower ends of the outer case and the middle case are held so that the lower rod is airtight and slidable, and the space below the tip of the lower rod and formed by the outer case and the middle case is set. An aerial work vehicle characterized in that a space formed by the middle case and the inner case and acting on the upper rod is communicated so that pressure oil can flow.

Desirably, the present invention sets the center of the pair of hydraulic expansion / contraction mechanisms at X.
Uses two sets of lifting mechanisms that are rotatably combined in a letter shape,
Each set of lifting devices are arranged side by side and can be rotated freely.
(EN) Provided is an aerial work vehicle, which is characterized in that the rotation center of the character shape is arranged so as to be on the same horizontal axis.

Desirably, the present invention is characterized in that the distance between the tips of a pair of upper rods connected to the lower surface of the lift table and the distance between the lower ends of a pair of lower rods connected to the upper surface of the vehicle body are the same. It provides a car.

Desirably, the present invention provides an aerial work vehicle characterized in that a kick mechanism for pushing up the center of the cylinder body of the lifting mechanism is provided on the upper surface of the vehicle body.

Is provided.

[Action]

In the present invention, the elevating mechanism is composed of a pair of cylinder bodies combined in an X shape, and the multistage rods are telescopically inserted from both ends of each cylinder body. The inside of the cylinder body is hermetically sealed, and an airtight hydraulic chamber is formed so that the lower rod and the upper rod form a part of the structure of the hydraulic cylinder. Therefore, two hydraulic chambers are formed inside the cylinder body, and the lower rod and the upper rod can be expanded and contracted directly from the cylinder body by hydraulic pressure.

Since the hydraulic chambers of the multistage rod and the upper stage rod are communicated with each other, the extension of the lower stage rod and the extension of the upper stage rod have the same length. Therefore, the two cylinders that are rotatably connected in the center form an X shape and rotate, and the lower rod is connected to the vehicle body by a pin, and the upper rod is connected to the lift table by a pin. Because
When viewed from the side, the entire body expands and contracts so as to form an X-shape, and at the same time, the cylinder body rotates, so that the elevating table is always maintained in a horizontal state and raised.

〔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 of being lifted to the position, and FIG. 4 is a side view showing a state of lowering the lifting platform to the lowest 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. The outriggers 5 for fixing the vehicle body 1 to the ground are fixed to the center of the vehicle body 1 and to the left and right of the rear portion. An elevating mechanism 6 is placed on the upper surface of the vehicle body 1, an elevating table 7 that vertically moves up and down is located on the upper surface of the elevating mechanism 6, and a kick mechanism 9 is provided at the center of the upper surface of the vehicle body 1. Is attached.

In this embodiment, two sets of lifting mechanisms 6 are provided, and each lifting mechanism 6 includes two cylinder bodies 10 and a lower rod 11 inserted from the lower end of the cylinder bodies 10.
And the upper rod 1 inserted from the upper end of the cylinder body 10.
2, and a connecting mechanism 13 that rotatably connects the centers of both cylinder bodies 10. Lifting mechanism 6 for each set
The center of the inner side surfaces of the pair of cylinders 10 is pivotally mounted in an X shape so as to be rotatable by the connecting mechanism 13, and the lower rod 11 has a connecting piece 14 at the lower end thereof and an upper rod.
Connection pieces 15 are fixed to the upper ends of the respective pieces 12. The connecting piece 14 of the lower rod 11 is rotatably connected to four fixing pieces 16 fixed to the upper, lower, left and right sides of the upper surface of the vehicle body 1 by a pin, and the connecting piece 15 of each upper rod 12 is connected to the lift table 7. The four fixed pieces 17 fixed to the front, rear, left and right of the lower surface of the are rotatably connected by pins. The fixing pieces 16 and 16 are arranged at the same intervals as the fixing pieces 17 and 17, and the vehicle body 1 and the lifting table 7 are configured to be parallel to each other as the lifting mechanism 6 extends while rotating in the X shape. is there.

The kick mechanism 9 is provided at the center of the upper surface of the vehicle body 1 and in the middle of the fixing pieces 16 and 16, and the kick mechanism 9 is composed of a hydraulic cylinder 18 that expands and contracts in the vertical direction. A push-up body 19 extending in the lateral direction is fixed to the upper end of the hydraulic cylinder 18 so as to come into contact with the central lower surface of the cylinder body 10 in a direction perpendicular to the longitudinal direction of the cylinder body 10.

Next, FIGS. 5 and 6 are detailed explanations of the inside of the cylinder body 10 that constitutes the elevating mechanism 6. FIG. 5 is a side sectional view of the cylinder body 6, and FIG.
FIG.

The cylinder body 10 is composed of an outer case 21, a middle case 22, and an inner case 23. The inner diameter of the outer case 21 is formed to be slightly larger than the outer diameter of the lower rod 11, and the outer diameter of the middle case 22. Is set to be slightly smaller than the inner diameter of the lower rod 11. The outer diameter of the upper rod 12 is set slightly smaller than the inner diameter of the middle case 22, and the inner case 23
The outer diameter of is set smaller than the inner diameter of the upper rod 12. For this reason, as shown in FIG. 6, the outer case 21, the lower rod 11, the middle case 22, the upper rod 12, and the inner case 23 are arranged concentrically, and the inner and outer diameters thereof are slightly different. The thickness is such that a gap can be formed between each member.

A disc-shaped end ring 24 is fixed below the outer case 21 (on the left side in FIG. 5).
A slide ring 25 is closely attached to the left side of 24, and the end ring 24 and the slide ring 25 are fixed by a screw 26. The inner diameter of the end ring 24 is made substantially the same as the inner diameter of the outer case 21, but the inner diameter of the slide ring 25 is made substantially equal to the outer diameter of the lower rod 11, and the lower rod 11 is It slides while making airtight contact with the inner peripheral surface. An end ring 27 is fixed to the upper side of the outer case 21 (right side in FIG. 5), and a slide ring 28 is closely fixed to the right side of the end ring 27. The inner diameter of the end ring 27 is made substantially the same as the inner diameter of the middle case 22, the slide ring 28 is made substantially the same as the outer diameter of the upper rod 12, and the upper rod 12 is in airtight contact with the slide ring 28. You can slide while.

An end ring 29 having an outer diameter substantially the same as that of the middle case 22 and an inner diameter substantially the same as that of the inner case 23 is airtightly fixed to the left end of the middle case 22.
A slide ring 30 is fixed to the left end of the with a screw 31. The outer diameter of the slide ring 30 is the lower rod 11
The inner diameter of the lower rod 11 is substantially the same as the inner diameter of the lower ring 11, and the lower rod 11 can slide on the outer periphery of the slide ring 30 while airtightly contacting the outer periphery. Further, an end ring 32 having an outer diameter substantially equal to the outer diameter of the inner case 23 is fixed to the right end of the inner case 23, and a slide ring is provided on the right side of the end ring 32.
33 is in close contact, the end ring 32 and the slide ring
It is fixed to 33 with screws 34. The outer diameter of the slide ring 33 is set to be substantially the same as the inner diameter of the upper rod 12, and the upper rod 12 can slide while being in airtight contact with the slide ring 33.

In this way, outer case 21, middle case 22, inner case 23
As a result, two spaces are formed concentrically inside the cylinder body 10, and these spaces act as hydraulic cylinders. A ring-shaped piston ring 35 is slidably inserted between the outer case 21 and the middle case 22, and the piston ring 35 is arranged between the outer case 21 and the middle case.
It can move in an airtight manner in a cylindrical space formed by 22, and the upper end of the lower rod 11 is fixed to the left side of this piston ring 35. Next, a ring-shaped piston ring 36 is provided between the middle case 22 and the inner case 23.
The piston ring 36 is inserted in the middle case 22.
The cylindrical space formed by the inner case 23 can be moved in an airtight manner, and the lower end of the upper rod 12 is fixed to the right side of the piston ring 36.

A plurality of communication holes 37 for flowing pressure oil are formed around the upper end of the lower rod 11, and a plurality of communication holes 38 for flowing pressure oil are formed around the lower end of the upper rod 12. It is opened individually. Further, a plurality of flow holes 29 are formed around the right end of the middle case 22 to connect the spaces of the outer case 21 and the inner case 23. Oil passage holes 40 and 41 are opened at two locations on the outer circumference of the end ring 27. Of these, one of the oil passage holes 40
Is communicated with the space formed by the outer case 21 and the middle case 22, and the other oil passage hole 41 is formed by the middle case 22 and the inner case.
It communicates with the space formed by 23.

In this way, outer case 21, middle case 22, inner case 23
As a result, a closed space divided into two layers, the inner and outer circumferences, is formed inside the cylinder body 10, and its sectional structure is shown in FIG. Outer case 21 and middle case
The relationship between the cross-sectional area formed by 22 and the cross-sectional area formed by the middle case 22 and the inner case 23 is shown in FIG.

The outer case 21, the middle case 22, and the inner case 23 are arranged concentrically. In the relationship between the cross-sectional area A of the space formed by the outer case 21 and the middle case 22 and the cross-sectional area B of the space formed by the middle case 22 and the inner case 23, the outer case
By designing the inner and outer diameters of 21, the inner case 22, and the inner case 23, the cross-sectional area A and the cross-sectional area B are designed to be the same.

Next, the connecting mechanism 13 will be described in detail with reference to FIG. This connecting mechanism 13 is capable of connecting two hydraulic cylinders 10 rotatably in the center thereof, and is composed of two opposing mechanisms as a pair.

First, at the center of one cylinder body 10, a fixed band 45 having its outer circumference wound in a band shape is fixed, and on the side surface of this fixed band 45, a cylindrical shape is formed in a direction perpendicular to the axial direction of the cylinder body 10. The rotating shaft 46 is projected and fixed. An engaging groove 47 is formed by cutting on the outer circumference of the tip of the rotary shaft 46 so as to go around the outer circumference. Further, a fixing band 48 is fixed to the outer circumference of the center of the other opposing cylinder body 10 so as to go around the outer circumference, and the side surface of this fixing band 48 is perpendicular to the axial direction of the cylinder body 10. A rotating cylinder 49 having a cylindrical shape is projected and fixed.
The inner diameter of the rotary cylinder 49 is set to be substantially the same as the outer diameter of the rotary shaft 46, and the two cylinder bodies 10 can rotate with each other by inserting the rotary cylinder 49 into the rotary shaft 46. And, a pin hole 50 is opened at an upper position and a lower position near the base of the rotary cylinder 49, and a pin 52 fixed to an engaging body 51 is inserted into the pin 50, and the pins 52 are engaged with each other. It is fitted so as to mesh with the groove 47. These engagement bodies 51 are fixed to the rotary cylinder 49 with screws 53.

Next, FIG. 9 shows the configuration of the hydraulic circuit in this embodiment.

The suction side of the hydraulic pump 60 operated by the engine 61 is connected to the oil tank 62, and the discharge side of the hydraulic pump 60 is connected to the three-way switching type switching valve 63. This switching valve 63
One of them is connected to the oil passage hole 40, and at the same time, connected to the hydraulic cylinder 18. An oil passage hole 41 communicates with the other side of the switching valve 63, and at the same time, is connected to the discharge side of the hydraulic cylinder 18.

Next, the operation of this embodiment will be described.

In order to raise and lower the platform 7, the engine 61 attached to the vehicle body 1 is operated, and the hydraulic pump 60 is driven by the engine 61.
To suck oil from the oil tank 62 to generate hydraulic pressure. When the switching valve 63 is operated to supply the pressure oil to the oil passage hole 40, the pressure oil supplied to the oil passage hole 40 is formed into the ring-shaped cylinder chamber C formed by the outer case 21 and the middle case 22. Is supplied to. Since the pressure oil increases the pressure in the cylinder chamber C, the piston ring 35 acts so as to be pushed to the left in FIG. 5, and the lower rod 11 generates a force to push the cylinder body 10 to the left. To do.

However, when the lift platform 7 is at the lowest position as shown in FIG. 4 in this aerial work vehicle, the cylinder body 10, the lower rod 11, and the upper rod 12 are arranged in parallel in a straight line, respectively. No component force is generated in the direction in which the connecting mechanism 13 is rotated in the X shape, and the lifting platform is not raised. However, since the hydraulic pressure is also supplied to the hydraulic cylinder 18 from the switching valve 63 at the same time, the hydraulic cylinder 18 operates to lift the push-up body 19 upward. For this reason,
The push-up body 19 comes into contact with the lower surface of the center of the cylinder body 10 and lifts the cylinder body 10 to change it into a slightly X-shape. By the action of this kick mechanism 9, the lifting mechanism 6
The cylinder body 10 of the book is transformed from a parallel state to an X-shaped state in which it is crushed a little.

Following the above operation, the pressure oil supplied from the oil passage hole 40 into the cylinder chamber 10 pushes the piston ring 35 and pushes the lower rod 11 from the left end of the slide ring 25 to gradually increase its length. It works as it goes. With the movement of the piston ring 35, the pressure oil in the cylinder chamber D formed by the outer case 21 and the middle case 22 flows into the flow hole 39.
Through, and flows into the cylinder chamber E formed by the middle case 22 and the inner case 23. When pressure oil is supplied into the cylinder chamber E, the piston ring 36 is pushed to the right in FIG. 5, and at the same time as the piston ring 36 is moved, the upper rod 12 is pushed to the right and the upper stage is moved. The rod 12 moves further to the right than the right end of the slide ring 28.

In this way, the lower rod 11 and the upper rod 12 respectively extend in the left-right direction from both ends of the cylinder body 10, and the distance between the connecting pieces 14 and 15 gradually increases. With the rightward movement of the piston ring 36, the pressure oil in the cylinder chamber F formed by the middle case 22 and the inner case 23 is discharged from the oil passage hole 41, and the pressure oil discharged from the oil passage hole 41 is discharged. Oil switching valve 63
Is returned to the oil tank 62 via.

The total length of the elevating mechanism 6 combined in three stages by the extension of the lower rod 11 and the upper rod 12 is long, but the tips of the lower rod 11 and the upper rod 12 are the
Since it is pin-connected to the fixing pieces 16 and 17 fixed to the lifting table 7, when the entire length is extended, the extending direction is divided into upward force, and the lifting table 7 is gradually lifted upward. become. At this time, since the pair of cylinder bodies 10, 10 are connected by the rotary shaft 46 and the rotary cylinder 49, both of them rotate so as to form an X shape with the central axis of the rotary shaft 46 as the center of rotation, and the lifting mechanism is moved. 6 will be launched.

When the lift table 7 has risen to a certain height, if the switching valve 63 is switched to "neutral", the supply of pressure oil to the oil passage hole 40 is cut off, and the piston rings 35 and 36 are at their stopped positions. Therefore, the elevating table 7 is maintained at its height position.

Further, in order to lower the lift table 7, the switching valve 63 is switched in the "reverse" direction contrary to the above, and pressure oil is added to the oil passage hole 41 to move the piston ring 36 leftward in FIG. Push it. Then, the upper rod 12 moves toward the inside of the cylinder body 10, and at the same time, pressure oil flows into the cylinder chamber D through the flow hole 39, pushing the piston ring 35 to the right in FIG. The rod 11 is retracted toward the inside of the cylinder body 10. Therefore, the lower end of the lower rod 11 and the upper rod
The distance from the upper end of 12 is reduced, and the lifting platform 7 is gradually lowered.

The pressure oil remaining in the cylinder chamber C is
The oil is discharged via 40 and is returned to the oil tank 62, contrary to the above.

〔The invention's effect〕

Since the present invention is configured as described above, the lifting mechanism can be configured by a plurality of hydraulic cylinders, and the structure is extremely simple. Further, a synchronizing mechanism such as a chain for synchronizing the lower rod and the upper rod is not required, which facilitates manufacturing and simplifies maintenance.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a lifting platform of an aerial work vehicle according to an embodiment of the present invention is lifted, and FIG. 2 is a side view of the same.
FIG. 3 is a rear view of the same as above, FIG. 4 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 lifting mechanism, and FIG. FIG. 7 is a longitudinal sectional view, FIG. 7 is an explanatory view showing a sectional area of a cylinder chamber inside the cylinder body, FIG. 8 is an exploded perspective view showing a constitution of a connecting mechanism for connecting two cylinder bodies, and FIG. It is a piping diagram which shows the structure of the hydraulic circuit in an example. 1 ... Car body, 6 ... elevation mechanism, 7 ... elevation platform, 9 ... kick mechanism, 10 ... cylinder body, 11 ... lower rod, 12
…… Upper rod, 13 …… Coupling mechanism, 21 …… Outer case, 22
…… Middle case, 23 …… Inner case.

Claims (7)

[Claims] 1. A center of a movable vehicle body, a lift table that is located above the vehicle body and can be vertically moved up and down, and a center of a pair of hydraulic expansion / contraction mechanisms which are interposed between the vehicle body and the lift table and can expand and contract in three stages. In an aerial work vehicle having an elevating mechanism that is rotatably combined in a V-shape, a pair of cylinders whose centers are rotatably connected in an X-shape are opened at both ends, and the upper rod is slid from one of the opening ends. The lower rods are slidably inserted from the other open ends, the upper ends of the pair of upper rods are connected to the lower surface of the lift table at intervals, and the lower ends of the pair of lower rods are connected to the vehicle body. They are connected at intervals on the upper surface to form a closed space where hydraulic pressure is supplied to each of the lower rod and the upper rod in the cylinder body, and the hydraulic area acting on the lower rod and the hydraulic area acting on the upper rod are almost An aerial work vehicle characterized by equalization. 2. The aerial work vehicle according to claim 1, wherein each of the cylinder body, the upper rod and the lower rod is formed in a cylindrical shape. 3. A center of a movable vehicle body, an elevating table located above the vehicle body and capable of vertically moving up and down, and a pair of hydraulic expansion / contraction mechanisms interposed between the vehicle body and the elevating table and capable of expanding / contracting in three stages. In an aerial work vehicle having an elevating mechanism rotatably combined in a V shape, a pair of hydraulic expansion and contraction mechanisms includes a pair of cylinder bodies whose center is rotatably connected in an X shape, and one open end of each of the cylinder bodies. An upper rod slidably inserted from
Each cylinder body consists of a lower rod slidably inserted from the other open end of the cylinder body.Each cylinder body has a cylindrical outer case with both ends open, and both ends are open so that the outer diameter is smaller than the inner diameter of the outer case. The inner case has a cylindrical shape with a small diameter, and the inner case has a cylindrical shape whose both ends are open and whose outer diameter is smaller than the inner diameter of the outer case. The lower case of the inner case and the lower case of the inner case are airtightly connected, and the cylindrical lower rod is slidably and airtightly inserted into the gap formed by the outer case and the middle case from the lower end of the outer case. The cylindrical upper rod is slidably and airtightly inserted into the gap formed by the middle case and the inner case from the upper end of the, and the annular hydraulic cross-sectional area formed by the outer case and the middle case acts on the lower rod. Medium case and inner case An aerial work vehicle characterized in that the hydraulic cross-sectional areas of the annular shape formed by the ribs and acting on the upper rod are set to be substantially equal. 4. A center of a movable vehicle body, a lift table which is located above the vehicle body and which can be vertically moved up and down, and a pair of hydraulic expansion and contraction mechanisms which are interposed between the lift table of the vehicle body and can expand and contract in three stages. In an aerial work vehicle having an elevating mechanism rotatably combined in a V shape, a pair of hydraulic expansion and contraction mechanisms includes a pair of cylinder bodies whose center is rotatably connected in an X shape, and one open end of each of the cylinder bodies. An upper rod slidably inserted from
Each cylinder body consists of a lower rod slidably inserted from the other open end of the cylinder body.Each cylinder body has a cylindrical outer case with both ends open, and both ends are open so that the outer diameter is smaller than the inner diameter of the outer case. The inner case has a cylindrical shape with a small diameter, and the inner case has a cylindrical shape whose both ends are open and whose outer diameter is smaller than the inner diameter of the outer case. The lower case of the inner case and the lower case of the inner case are airtightly connected, and the cylindrical lower rod is slidably and airtightly inserted into the gap formed by the outer case and the middle case from the lower end of the outer case. The cylindrical upper rod is slidably and airtightly inserted into the gap formed by the middle case and the inner case from the upper end of the, and the annular hydraulic cross-sectional area formed by the outer case and the middle case acts on the lower rod. Medium case and inner case The hydraulic cross-sections of the ring shape formed by the upper and lower rods are set to be almost equal, and the lower openings of the outer and middle cases are held so that the lower rods are airtight and slidable. Then, the space below the tip of the lower rod and formed by the outer case and the middle case and the space formed by the case and the inner case and acting on the upper rod were communicated so that pressure oil could flow. An aerial work vehicle characterized by that. 5. An X-shaped rotation in which two sets of lifting mechanisms, each of which is formed by rotatably combining the center of a pair of hydraulic expansion and contraction mechanisms in an X-shape, are used and the lifting devices of each set are arranged in parallel, are rotatable. The aerial work vehicle according to claim 1, 3 or 4, wherein the centers are arranged so as to have the same horizontal axis. 6. The distance between the tips of a pair of upper rods connected to the lower surface of the lift table and the distance between the lower ends of a pair of lower rods connected to the upper surface of the vehicle body are the same. Or the aerial work vehicle described in 4. 7. An aerial work vehicle according to claim 1, wherein a kick mechanism for pushing up the center of the cylinder body of the lifting mechanism is provided on the upper surface of the vehicle body.