JPH0747472B2 - lift device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elevating device capable of moving an elevating table up and down above a vehicle body to elevate personnel and materials to a high place, and particularly to a simple elevating boom body. Although it has a structure, it has the same function as the conventional lifting device with multiple telescopic boom bodies, and furthermore, by vertically controlling the elevating and extending motions of the telescopic boom unit with a simple structure, the platform can be lifted. The present invention relates to a lifting device that can lift a vehicle vertically upward with respect to a vehicle body.

[0002]

2. Description of the Related Art Elevating devices for raising and lowering elevators are often used for assembling, painting, and repairing in high places such as highways and building construction. Workers and materials are placed on the elevators to lift or lower. I was working on it.

In a conventional lifting device, a pair of arms are pivotally supported at the center thereof to form one set, and a pantograph-like expansion / contraction mechanism in which a plurality of sets of arms are vertically connected is used (so-called scissor type). In this mechanism, in order to increase the maximum lifting height of the lifting device, it is necessary to lengthen each arm or increase the number of arms to be connected. For this reason, when designing an elevating device that can raise the ascending height, a large number of pantographs must be used, and the elevating device height when the telescopic mechanism is folded increases, making it possible for workers to use the elevating platform. The work of getting on and off, loading and unloading materials was troublesome.

For this reason, a lifting device has been devised in which a plurality of booms are telescopically inserted in the arm so that one arm can extend in the lengthwise direction (for example, Japanese Patent Application No. 56/1975). No. 134487, Japanese Patent Application No. 1956
1065). With this newly proposed lifting mechanism,
Two intermediate booms are assembled into an X-shape so that they can be rotated about their centers, two intermediate booms are arranged in parallel, and each upper boom and lower boom are inserted with their respective intermediate booms inserted in the upper and lower ends. Was connecting the car body and the lift. Therefore, the number of booms required is inevitably large, the number of constituent members is extremely large, manufacturing and assembling are complicated, and the price is high.

Further, in such a sliding mechanism, the sliding portion of each boom becomes extremely large, and normally, at this sliding point, a sliding component made of a polyamide-based synthetic resin material is used in order to maintain good sliding. It had to be installed. These sliding parts must be replaced regularly, the number of parts for replacement is large, and the inspection and maintenance are expensive and the work is troublesome.

For this reason, there has been proposed an elevating device for extending and retracting one telescopic boom body so as to be Z-shaped when viewed from the side (Japanese Patent Application No. 95797/1984). With this new mechanism, you can expand and contract one telescopic boom in the longitudinal direction,
It is necessary to perform two controls for vertically restraining the telescopic boom body, and it is preferable to perform both controls in synchronization. In order to control both of them, a telescopic amount measuring device that measures the amount of extension of the telescopic boom and an angle measuring device that measures the depression angle of the telescopic boom from the horizontal are required. The detection signal must be calculated to control the depression hydraulic cylinder and the extension hydraulic cylinder, respectively. Arranging these measuring devices in the lifting device has a complicated structure in terms of assembly, and further requires a computer (microcomputer, etc.) for calculating the signals output from both measuring devices. . The price of each of these measuring instruments and computers is high, which has been a factor in raising the price of the lifting device as a whole. The price of a computer does not affect the price of the entire product for a large lifting device, but for a small lifting device, the cost ratio of the computer to the price of the entire lifting device is high, making it a small lifting device. Had a heavy burden.

[0007]

As described above, the newly proposed Z-shaped lifting device has a smaller number of parts than the conventional scissor-type lifting device and X-shaped telescopic lifting device. Although it has excellent characteristics, it has a drawback that the control mechanism is complicated and expensive because it is necessary to control the depression and extension of the telescopic boom at the same time.

For this reason, it is easy to lift the platform in the vertical direction with respect to the vehicle body without using the extension amount of the telescopic boom and the measuring device for the inclination angle and the computer for calculating the signal from these. Development of a control mechanism was desired. In particular, a mechanism that can be controlled without using an expensive electronic device such as a computer has been desired.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a movable vehicle body, a flat lifting platform arranged above the vehicle body, and a plurality of booms arranged between the vehicle body and the lifting platform are inserted in the longitudinal direction thereof. The telescopic boom body, the elevating means which is interposed between the vehicle body and the telescopic boom body to lift the telescopic boom body diagonally, and the extending means which is housed inside the telescopic boom body and extends the telescopic boom body. In the lifting device, the vehicle body, the lifting platform, and the telescopic boom body are arranged so as to be Z-shaped when viewed from the side, and the telescopic boom body is extended and lowered and the elevator platform can be moved up and down. Connect the tip of the first stretch wire to one side of the lower surface of the platform, wind the first stretch wire around the first winding drum on the other side of the vehicle body, and tip the second stretch wire to the other lower surface of the lifting platform. The second stretch wire is wound around the second winding drum on one side of the vehicle body, one of the winding drums is rotatably supported, and the other winding drum is rotatable and horizontal. So that it can be moved in any direction, the deviation of the amount of pulling out of the first and second extension wires is detected by the amount of movement of the other winding drum, and the elevation means and extension means are controlled to move the lifting platform. Provided is an elevating device characterized in that the tip end of a telescopic boom body is controlled to move vertically with respect to a vehicle body while being kept horizontal.

[0010]

In the present invention, the tips of the first and second extension wires are connected to one and the other of the lower surface of the lift table, respectively.
The first stretch wire extends toward the other side of the vehicle body and is wound around the first winding drum of the vehicle body. The second stretch wire extends toward one side of the vehicle body and is wound around the second winding drum of the vehicle body.
Therefore, the two stretched wires are arranged so as to have an X shape when viewed from the side. When both the elevating means and the elongating means act at the same time, the two elongating wires are extended obliquely along the respective long sides of the X-shape, and the two elongating wires are pulled out while rotating the first and second winding drums. become. At this time, one winding drum is rotatably supported (the bearing holding the rotating shaft does not move), while the other winding drum is held rotatably and horizontally movable. Therefore, when a difference occurs in the amount of pulling out the pair of extension wires, the position of the other winding drum fluctuates in the horizontal direction.
Since the amount of movement of this winding drum appears as the difference in the pull-out length of both extension wires, by detecting the movement of this winding drum and controlling the elevation means and extension means,
It is possible to correct the tip of the telescopic boom so that it can always move in the vertical direction with respect to the vehicle body. As a result, the lifting platform can move in a straight line vertically upward with respect to the vehicle body.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 a lift of an elevator according to an embodiment of the present invention is lifted, FIG. 2 is a side view of the lift being lowered to the lowest position, and FIG. 3 is a front view of the same. Figure, Figure 4
[Fig. 4] is a side view showing a state in which the lift is raised to the maximum height position.

A front wheel 2 and a rear wheel 3 are rotatably supported on the front, rear, left and right of the movable vehicle body 1 so that the vehicle body 1 can move freely. A driving box 4 accommodating an engine, a hydraulic pump and the like is attached to the lower part of the vehicle body 1.

A pair of shaft support pieces 5 are fixed to one end of the upper surface (on the rear wheel 3 side) of the vehicle body 1 with a space therebetween, and a space between the shaft support pieces 5 has a quadrangular cross section and is hollow inside. The lower boom 6 is inserted, and the shaft support piece 5 and the lower end of the lower boom 6 are rotatably connected by a pin 7. In addition, pin 7
Is fixed to the lower boom 6 side, and the pin 7 can rotate relative to the shaft support piece 5. On the upper surface of the vehicle body 1, a pair of pin stoppers 8 are fixed to the left and right of the position opposite to the shaft support piece 5 (on the front wheel 2 side). A depression-use hydraulic cylinder 9 is interposed between the depressions as a depression means.

A tip end of the lower boom 6 is opened in a square section, and an inner hollow middle boom 10 having a square section is slidably inserted in the opening in the opening.
Similarly, an inner hollow tip boom having a quadrangular cross section is slidably inserted in the longitudinal opening of the middle boom 10. A cover body 12 having a U-shaped cross section and opening downward is fixed to the tip of the tip boom 11, and the inner surface of the upper portion of the cover body 12 is spaced so as to be parallel to the outer side of the lower boom 6. There is a gap between the front boom 11 and the cover body 12 so that the lower boom 6 can be inserted therethrough.
The lower boom 6 is set to have a length about the length of the vehicle body 1, and the middle boom 10 and the front boom 11 are set to have substantially the same length as the vehicle body 1. The telescopic boom unit 1 includes the lower boom 6, the middle boom 10, and the front boom 11.
3 is formed.

Next, in the figure, reference numeral 16 is a flat elevator having a floor area substantially the same as that of the vehicle body 1. The other end of the lower surface of the elevator 16 (on the front wheel 2 side) is provided with a pair of shafts with a space therebetween. Support piece 14
Is fixed, and the tip of the cover body 12 is inserted between both the shaft support pieces 14. Then, the shaft support piece 14 and the cover body 1
The pin 2 is rotatably connected to the pin 2. In addition, a pair of pin stoppers 1 are provided on both sides of the lower surface of the lift table 16 on the opposite side of the shaft support piece 14 (on the rear wheel 3 side).
7 are fixed, and a hydraulic cylinder 18 for posture correction is interposed between each pin 17 and both sides of the cover body 12. Further, handrails 19 are vertically planted around the upper surface of the lifting table 16 so as to prevent a boarded worker from falling.

A wire hook 55 is fixed to one of the lower surfaces of the lift table 16 (right side of FIGS. 1, 2, and 3), and the other of the lower surface of the lift table 16 (FIGS. 1, 2, 3). A wire hook 61 is fixed to the left side of the. The wire hook 55 is connected to the tip of a first stretch wire 56, which is made by twisting a plurality of thin metal wires to give flexibility, and the stretch wire 56 descends along the tilt direction of the telescopic boom body 13. Then, the other end of the vehicle body 1 (FIG. 1, FIG. 2, FIG.
It is inserted into a lead-in hole 58 opened on the left side of the drawing.
Further, the wire hook 61 is connected to the tip of a second stretch wire 62, which is made by twisting a plurality of thin metal wires to give flexibility, and this stretch wire 62 is connected to one side of the vehicle body 1 (see FIGS. 1 and 2). , The right side of FIG. 3). A thin holding plate 63 is erected at one corner of the upper surface of the vehicle body 1, and a pulley 64 is pivotally supported on the side surface of the holding plate 63. The extension wire 62 is attached to the pulley 64.
Are in contact. The extension wire 62 is directed downward along the outer periphery of the pulley 64, and is inserted into a lead-in hole 65 that is opened through one side of the vehicle body 1. In this way, the two extension wires 56 and 62 are stretched between the vehicle body 1 and the lift 16 so as to form an X shape.

Next, FIG. 5 shows the internal construction of the telescopic boom body 13. The lower boom 6, the middle boom 10, and the front boom 11 are telescopically inserted so that they can be expanded and contracted. The cover body 12 attached to the tip of the tip boom 11 has an upper side of about 2/3 of the total length of the lower boom 6 and a lower side of about 1/3, and the left side in FIG. Is formed so as to be inclined downward. This lower boom 6
A pin hole 21 for connecting the hydraulic cylinder 9 is provided in the upper part of the cover body at a position of about 1/3 from the left end thereof, and at the lower part of the cover body 12 at a position of about 1/2 of its entire length. Has a pin hole 22 for connecting the hydraulic cylinder 18.

A shaft supporting portion 23 is fixed to the upper end of the cover body 12 at the left end thereof, and a roller 24 which comes into contact with the upper surface of the lower boom 6 is supported inside the shaft supporting portion 23. A sprocket wheel 41 is pivotally supported on the upper end of the front boom 11 (right side in FIG. 5), and the sprocket wheel 42 is located at a position about 1/3 of the length from the lower end of the front boom 11 (left side in FIG. 5). Is pivotally supported. A chain 43 is wound between the two sprocket wheels 41, 42, and each end of the chain 43 is located at the upper end of the middle boom 10 (position on the right side C in FIG. 5). On the right side of the chain 43, rollers 44, which are spacers made of a slippery material formed of about ten polyamide resins, are arranged at intervals.

Further, FIG. 6 shows a cross section taken along the line AA in FIG.

Auxiliary plates 26 are fixed to both sides of the tip of the middle boom 10 (right end in FIG. 5). This auxiliary plate 2
A support shaft 28 is fixed to a lower portion of the support shaft 6, and the support shaft 28 is located inside the auxiliary plate 26, and the support shaft 28 is attached to the front boom 11 respectively.
A roller 29 that comes into contact with the lower surface of the outer periphery of the roller is rotatably supported. A pulley 30 that rotates a chain (not shown) that connects the lower boom 6 and the front boom 11 is pivotally supported at the center of the support shaft 28. Further, the auxiliary plate 26 is provided with a slider 31 that contacts the outside of the front boom 11 and a slider 32 that contacts the inside of the cover body 12.

A pair of sprocket wheels 41 are pivotally supported by shafts 45 on the left and right of the inner wall of the front boom 11, and a chain 43 is wound around each sprocket wheel 41. A plurality of rollers 44 are spaced apart from each other.

Next, FIG. 7 shows a cross section taken along the line BB in FIG.

A shaft support portion 2 provided on the lower end of the cover body 12
A pair of support pieces 33 are fixed to the left and right sides of the inside of the shaft 3 so as to be parallel to the side surfaces thereof.
Pins 43 are installed between the three pins, and each pin 3
The roller 24 is rotatably supported at 4. A liner 35 that abuts the side surface of the lower boom 6 is fixed to the side surface of the cover 12, and a liner 36 that abuts the outer circumference of the middle boom 10 is fixed to the lower boom 6. Sprocket wheels 42 are rotatably supported on the left and right inner walls below the front boom 11, respectively.
A chain 43 is wound around 2.

FIG. 8 is an enlarged view of the vicinity of the sprocket wheel 41 on the left side in FIG.

On the inner wall of the front boom 11, there is provided a pin 45 protruding and fixed from the side surface thereof.
5, the sprocket wheel 41 is rotatably supported, and a chain 43 is wound around the sprocket wheel 41. A rail 46 made of a synthetic polyamide resin is fixed to the upper surface of the boom 11 in parallel with the length direction of the front boom 11.
The roller of the chain 43 is brought into contact with the upper surface of 46 so that the roller can roll. A pair of L-shaped angle pieces 47 are connected to both sides of the chain 43, and a U-shaped shaft support body 48 having an upward opening is fixed between the angle pieces 47. There is a shaft 49 on this shaft support 48.
The roller 44 is axially supported by.

Next, FIGS. 9 and 10 show in detail the construction of the follow-up detection mechanism 68 used for synchronizing the extension operation and the elevation operation of the telescopic boom body 13 in this embodiment.

The extension wire 56 extends obliquely downward from one of the lower surfaces of the lift table 16 and is in contact with a pulley 57 pivotally supported by the pivot support piece 5. A lead-in hole 58 is opened in the vicinity of the shaft support piece 5 of the vehicle body 1 so as to penetrate vertically through the vehicle body 1, and a wire 56 extending from the lead-in hole 58 is inserted below the vehicle body 1. A pulley 59 is rotatably supported on the lower surface of the vehicle body 1 and below the pull-in hole 58, and the extension wire 56 is horizontally inverted by the pulley 59, and the extension wire 56 is in the follow-up detection mechanism 68. It is wound around. The extension wire 62 extends obliquely from the other lower surface of the lift 16 toward one of the vehicle bodies 1 and is brought into contact with a pulley 64 pivotally supported on one of the vehicle bodies 1. A pull-in hole 65 is opened through one side of the vehicle body 1 and below the pulley 64, and an extension wire 62 is inserted through the pull-in hole 65. A pulley 66 is axially supported on the lower surface of the vehicle body 1 below the lead-in hole 65, and the extension wire 62 is inverted by the pulley 66 to extend in the horizontal direction. The extension wire 62 is used for the winding drum 6 in the follow-up detection mechanism 68.
It is wound 07 times.

The follow-up detection mechanism 68 controls the elevating angle and the extension length of the telescopic boom body 13 in synchronism with each other. The follow-up detection mechanism 68 is fixed to the center of the lower surface of the vehicle body 1. The whole is fixed by the shaft support plates 70 and 71. Both of the shaft support plates 70 and 71 are thin steel plates arranged in parallel with a space therebetween, and the winding drums 60 and 67 are rotatably supported between the shaft support plates 70 and 71. is there. A spindle 72 is provided at the center of the winding drum 60.
Is pierced and fixed, and the shaft 72 is rotatably supported by a holding hole 73 opened in the shaft supporting plates 70 and 71, and is held at that position. In addition, the winding drum 67
A support shaft 74 is fixed through the center of the support shaft 74.
Are held by elongated holes 75 and 76 formed in the shaft support plates 70 and 71. These long holes 75 and 76 are the shaft support plates 7.
0 and 71 are slenderly opened so as to extend in the horizontal direction, and the support shaft 74 is rotatably supported by both elongated holes 75 and 76 so as to be rotatable and movable in the horizontal direction.

Further, sprocket wheels 77 and 78 are fixed to the respective support shafts 72 and 74, and the support shafts 72 and 74 are controlled so as to rotate at the same rotational speed between the sprocket wheels 77 and 78. The chain 79 is wound. The chain 79 regulates both the support shafts 72 and 74 so that the rotation angles thereof are the same. An arm 81, which is constantly urged upward by a spring 80, is provided on the lower side of the chain 79, and a tension roller 82 provided at the tip of the arm 81 always keeps the chain 79.
The lower surface of the chain 79 is kept in contact with the lower surface of the chain so as not to loosen the chain 79. A contact plate 83 is rotatably inserted through the support shaft 74, and two limit switches 84 and 85 are located on the left and right of the contact plate 83. A sprocket wheel 86 is fixed to the outside of the shaft support plate 70 of the support shaft 72, and a chain 87 is wound around the sprocket wheel 86.
A sprocket wheel 88 is wound around the other side of 7, and the spcket wheel 88 is connected to a motor 89.

Next, FIG. 11 shows a hydraulic circuit in this embodiment.

An oil tank 92 is connected to the suction side of a hydraulic pump 91 driven by the engine 90, and an electromagnetic control valve 93 for switching to three directions is connected to the discharge side of the hydraulic pump 91. Throttle valves 94 and 95 are connected to the discharge side of the control valve 93, a hydraulic cylinder 50 is connected to the throttle valve 94, and a hydraulic cylinder 9 is connected to the throttle valve 95. The discharge side of the hydraulic cylinder 50 is connected to the control valve 93, and the discharge side of the hydraulic cylinder 9 and the hydraulic cylinder 18 are connected.
The pressure side of the hydraulic cylinder 18 is connected in series.
The discharge side of is connected to the control valve 93. Each throttle valve 9
Electromagnetic synchronous valves 96 and 97 are connected to 4 and 95 in parallel, respectively.

Next, in FIG. 11, reference numeral 98 is a controller having an operating lever 99 operated by an operator, and by operating this lever 99, a command for moving the elevator 16 up and down is issued. . The control output for raising from the controller 98 is connected to the electromagnetic coil on the positive side of the control valve 93 via the raising instruction circuit 100. Also,
The control output from the controller 98 for lowering is connected to the electromagnetic coil on the opposite side of the control valve 93 via the lowering instruction circuit 101. The output of the descending instruction circuit 101 is also connected to the motor 89 and the switching pieces 105 and 106 of the switching device 104. A correction circuit 102 is connected to the output of the limit switch 84.
The output of 02 is connected to the switching piece 105 of the switching device 104. The switch 104 is a two-pole, two-contact type electric switch, and has two switching pieces 105, 106 and four fixed contacts 107, 108, 109, 110 built therein. The switching pieces 105 and 106 operate in conjunction with each other. The switching piece 105 is normally in contact with the fixed contact 107, but can be brought into contact with the fixed contact 108 by switching. Also, the switching piece 10
6 is normally in contact with the fixed contact 109, but can be contacted with the fixed contact 110 by switching.
A correction circuit 103 is connected to the output of the limit switch 85, and the output of the correction circuit 103 is connected to the switching piece 106 of the switch 104. The fixed contacts 107 and 110 of the switch 104 are connected to the electromagnetic coil of the tuning valve 97, and the fixed contacts 108 and 109 are connected to the electromagnetic coil of the tuning valve 96.

Next, the operation of this embodiment will be described.

FIGS. 2 and 3 show a state in which the telescopic boom body 13 is contracted and the lift table 16 is lowered to the lowest position. It is possible to mount it and raise the elevating table 16.

First, in order to raise the lift table 16,
The engine 90 in the drive box 4 is operated to drive the hydraulic pump 91, and the pressure oil is sucked from the oil tank 92 to generate the pressure oil. This pressure oil is transmitted to the control valve 93, and thereafter this pressure oil is transferred to the hydraulic cylinder 9,
By being supplied to 18, 50, the lift table 16 is raised or lowered.

<Rise of the lift 16>

When the lever 99 of the controller 98 is operated and tilted to the ascending side, the signal is transmitted to the ascending instruction circuit 100, and the signal is transmitted from the ascending instruction circuit 100 to the electromagnetic coil of the control valve 93 to cause the control valve 93 will be connected to the positive side. For this reason, the pressure oil from the hydraulic pump 91 is supplied to the throttle valve 9
Is transmitted to the hydraulic cylinder 50 via 4,
It is transmitted to the hydraulic cylinder 9 via the throttle valve 95. The pressure oil discharged from the hydraulic cylinder 9 is transmitted to the hydraulic cylinder 18, and the pressure oil discharged from the hydraulic cylinder 18 is returned to the oil tank 92 via the control valve 93. Since the hydraulic cylinders 9 and 18 are connected in series, the extension of both is always the same, and the telescopic boom unit 1
Regardless of the inclination angle of 3, the lift 16 will always be held horizontally. In this way, since the hydraulic cylinder 50 and the hydraulic cylinders 9 and 18 operate simultaneously, the telescopic boom body 13 has its entire length increased, and the extension of the hydraulic cylinder 9 causes the telescopic boom body 13 to incline and elevate with respect to the vehicle body 1. Will be done.

<Depression operation of the telescopic boom body 13>

When pressure oil is supplied to the hydraulic cylinders 9 and 18, the hydraulic cylinders 9 and 18 extend and rotate the lower boom 6 upward about the pin 7. Therefore, the telescopic boom body 13 is gradually depressed with respect to the vehicle body 1. This operation is performed first by switching the control valve 93 to the positive side, and the operations of the hydraulic cylinders 9 and 18 are performed.
It always operates in advance of the 0 operation.

<Expansion / contraction operation of the telescopic boom body 13>

Next, when the hydraulic pressure is supplied to the hydraulic cylinder 50 through the synchronous valve 94, the pressure acts so as to extend the telescopic boom body 13. First, the middle boom 10
Is slid out from the lower boom 6 and is pulled out, and the front boom 11 is slid out from the middle boom 10 to be pulled out to increase the distance between the pins 7 and 15. In this expansion and contraction operation, the roller 24 comes into contact with the upper surface of the lower boom 6 and moves while rolling.

Since there is a gap between the cover body 12 and the lower boom 6, the middle boom 10, and the front boom 11, rattling occurs, which may cause deformation due to the load. That is, the load of the lifting platform 16 is the hydraulic cylinder 1.
The stress is transmitted to the pin hole 22 via 8 and the stress of the pin hole 22 causes the cover body 12 to be bent downward. However, since the roller 24 rolls on the upper surface of the lower boom 6 as described above, the load is supported by the roller 24 and then transmitted to the lower boom 6,
The cover body 12 extends upward together with the front boom 11 while maintaining the lifting platform 16 at that height without being deformed.

When the lower boom 6 moves with respect to the cover body 12, the upper end of the lower boom 6 finally passes the lower surface of the roller 24. However, this telescopic boom body 13
When the robot expands and contracts, the tip of the middle boom 10 slides away from the upper end of the front boom 11 and is pulled out as described above. Therefore, the chain 43 is also pulled out from the inside of the front boom 11 and the sprocket wheel 41 is pulled out. , 42 while rolling. The chain 43 smoothly moves to slide on the rail 46, and at the same time, the roller 44 fixed to the chain 43 also follows.

For this reason, the rollers 44 fixed to the chain 43 also follow the middle boom 10 and move,
The roller 44 moves into the space formed between the front boom 11 and the cover body 12. These rollers 44 roll while contacting the inner wall of the cover body 12, and the load applied to the cover body 12 is transmitted to the upper end of the front boom 11 via the rollers 44, the chains 43, and the rails 46. It will be. Thus, even if the roller 24 is separated from the lower boom 6, the load of the cover body 12 comes into contact with each roller 44, and the cover body 12 is not deformed by the load of the elevating table 16.

In FIG. 12, (a) shows the initial state of extension, and the load applied to the pin hole 22 is supported by the roller 24. When the extension operation of the telescopic boom body 13 is further advanced, the lower boom 6 is pulled out from the cover body 12, and the roller 24 is separated from the upper surface of the lower boom 6 (see (B) in FIG. 13). . At this time, the roller 44 has already been pulled out by the middle boom 10 between the front boom 11 and the cover body 12, and the pin hole 2
The load applied to the cover body 2 is applied to the cover body 1 via the rollers 44 and the like.
2, the distance between the cover body 12 and the front boom 11 is kept parallel.

Further, when the middle boom 10 is pulled out and the distance between the front end of the front boom 11 and the front end of the front boom 11 increases, the rollers 44 roll at equal intervals between the front boom 11 and the cover body 12. The front boom 11 is sequentially withdrawn from the middle boom 10, and finally stops in the state of (c) of FIG. 14, and this state is the maximum extension position of the telescopic boom body 13. In this way, the contact and rolling of the rollers 24 and 44 are switched, and the telescopic boom body 13 slides smoothly.

Further, when the telescopic boom body 13 is contracted, the front boom 11 is moved so as to be inserted into the middle boom 10, the chain 43 is moved in the direction opposite to the above, and the roller 44 is moved to the front boom 11. It will be stored inside.
Then, when the upper end of the lower boom 6 contacts the lower end of the cover body 12, the roller 24 starts rolling on the upper surface of the lower boom 6. In this way, when the telescopic boom body 13 is contracted, contrary to the above, from (c) of FIG. 14, (b) of FIG.
It operates in the order of (2) (2), and the load applied to the cover body 13 switches from the roller 44 to the roller 24.

In this embodiment, the roller 44 as a spacer is formed in a cylindrical shape. However, if the spacer fills the gap between the cover body 12 and the tip boom 11, the spacer may have the same function as a quadrangle or a polygon. It is natural to achieve

<Maintenance of the lift table 16 in parallel>

As described above, the telescopic boom body 13 is restrained by the hydraulic cylinder 9, and at the same time the telescopic boom body 50 is extended by the hydraulic cylinder 50 in the longitudinal direction thereof. At this time, the hydraulic cylinder 18 has a hydraulic cylinder 9
Since the pressure oil is supplied in series from, it will be expanded at the same amount at the same time. The hydraulic cylinder 18 acts so as to enlarge the angle between the telescopic boom body 13 and the lifting platform 16, and since the extension amounts of the two hydraulic cylinders 9 and 18 are the same, the angle of the vehicle body 1 with respect to the telescopic boom body 13 is increased. And the angle of the lift 16 is the same. For this reason, the aerial work vehicle has a slightly Z-shape when viewed from the side, and the lifting platform 16 is always maintained parallel to the vehicle body 1, so that a worker or the like mounted on the lifting platform 16 may fall. Absent.

<Synchronization of extension and extension of the telescopic boom 13 and elevation>

As described above, since the hydraulic cylinders 9 and 18 and 50 operate independently of each other, the telescopic boom body 13 is restrained against the vehicle body 1 and the telescopic boom body 13 is restrained.
Is extended, and at the same time, the lift 16 is always kept parallel to the vehicle body 1. However, each hydraulic cylinder 9, 1
If 8 and 50 work independently, lift 1
Although 6 can rise, it cannot rise vertically to the plane of the vehicle body 1 and is displaced in the front-back direction with respect to the vehicle body 1 and rises, which makes it extremely unstable. If the extension of the hydraulic cylinder 9 is actuated quickly, the telescopic boom body 13 will be greatly elevated and there is a risk of falling backward. Further, if the hydraulic cylinder 50 extends quickly, the extension amount of the telescopic boom body 13 increases, and the center of gravity may move to the front of the vehicle body 1 and fall forward. Therefore, unless the respective operations of the hydraulic cylinders 9 and 18 and the hydraulic cylinder 50 are synchronized, it is impossible to raise the lift table 16 in the vertical direction. Therefore, the synchronous control between the depression and extension operations of the telescopic boom body 13 will be described with reference to FIG.

As described above, when raising the lift table 16, the lever 99 is tilted to the raising side, and the controller 98 transmits a signal to the raising instruction circuit 100 to connect the control valve 93 to the positive side. Therefore, the pressure oil of the hydraulic pump 91 is transmitted to the hydraulic cylinder 50 to extend the telescopic boom body 13. At the same time, pressure oil is also supplied to the hydraulic cylinder 9, so that the hydraulic cylinders 9 and 18 extend at the same time, and the telescopic boom body 13 is lifted upward with respect to the vehicle body 1. In this way, when viewed from the side, the vehicle body 1, the telescopic boom body 13, and the lifting platform 16 are deformed into a Z shape, and the lifting platform 16 is lifted above the vehicle body 1.

When the lift table 16 is lifted, the stretched wire 5 having the ends connected to the wire hooks 55 and 61.
6 and 62 are respectively pulled, and the rolling drums 60 and 67 are rotated and unrolled while rolling with the pulleys 57, 59 and 64 and 66, so that the two stretching wires 56 and 62 are wound.
Are drawn respectively. If the lift 16 is lifted straight upward with respect to the vehicle body 1, the two extension wires 56 and 62 will be stretched in an X-shape, and the X-shaped pulled-out length. If the amount is the same, the elevating table 16 is always lifted vertically upward from the vehicle body 1. This is (d) in FIG.
It is in the state shown by, and at this time both extension wires 56, 6
2 are drawn out by the same length, the interval between the winding drums 60 and 67 is L, and the contact plate 83
Is not in contact with any of the limit switches 84 and 85. If this state is maintained, the lift 16 will be
It will be lifted straight up vertically. At this time, since the rotation of both winding drums 60 and 67 is interlocked by the sprocket wheels 77 and 78 and the chain 79, they are always rotated at the same rotation speed, and the extension wire 56 causes the stretching wire 56 to rotate.
The rotation when pulled out from 0 always corresponds to the amount by which the extension wire 62 is pulled out from the winding drum 67 and rotates. In this way, the winding drum 6
If both 0 and 67 are the same, the extension wire 5
The pulling-out amounts of 6 and 62 are always the same length, and the interval L between the winding drums 60 and 67 does not change.

However, in this state, when the extension operation of the hydraulic cylinder 9 precedes the extension operation of the hydraulic cylinder 50, and the tilt angle of the telescopic boom 13 becomes larger than the extension amount of the telescopic boom body 13, the operation shown in FIG.
As shown in (e), the lift table 16 is displaced to the other side (leftward in FIG. 15) with respect to the vehicle body 1 and moves. In such a case, there will be a difference in the amount of extension of the extension wires 56 and 62, but the amount of rotation of both winding drums 60 and 67 is the same as described above. From this,
The winding drum 67 is dragged by the pulling force of the extension wire 62, and the support shaft 74 is moved rightward in FIG. 10 along the lengthwise direction of the elongated holes 75 and 76. As a result, the distance between the winding drums 60 and 67 is as shown in FIG.
As shown by, the length changes to L + S. Since the winding drum 67 and the support shaft 74 have moved rightward by the amount of S, the contact plate 83 inserted into the support shaft 74 comes into contact with the limit switch 85, so that the preceding expansion operation of the hydraulic cylinder 9 is corrected. Act on.

First, the limit switch 85 and the contact plate 83
When is touched, the signal from the correction circuit 103 outputs the switching piece 1
06, and is transmitted to the electromagnetic coil of the synchronous valve 96 via the fixed contact 109. Therefore, the synchronous valve 96 is electrically connected to form a bypass circuit outside the throttle valve 94, and the hydraulic pressure from the hydraulic pump 91 does not go through the throttle valve 94 directly.
It will flow to zero. Then, the amount of hydraulic pressure supplied to the hydraulic cylinder 50 becomes larger than the amount of hydraulic pressure supplied to the hydraulic cylinder 9, and the speed of expansion of the hydraulic cylinder 50 becomes faster than the speed of expansion of the hydraulic cylinder 9. Therefore, the telescopic boom body 1 operated by the hydraulic cylinder 50 is faster than the elevation speed of the telescopic boom body 13 operated by the hydraulic cylinder 9.
The extension amount of 3 is increased, and the lift 16 is corrected so as to horizontally move to the right in FIG. When the extension wire 56 is further pulled out and becomes equal to the extension length of the extension wire 62, since the rotation speeds of the winding drums 60 and 67 are the same, the winding drum 67 has a long hole 75,
It moves to the left in FIG. 10 along 76 and returns so as to eliminate the deviation S. Due to this return, when the state from FIG. 15 (e) to FIG. 15 (d) is reached, the contact plate 83 separates from the limit switch 85, the synchronous valve 96 closes, and hydraulic pressure is supplied to the hydraulic cylinder 50 via the throttle valve 94. Will be done.

Contrary to the above, when the extension speed of the hydraulic cylinder 50 becomes higher than the extension speed of the hydraulic cylinder 9 during the extension and elevation of the telescopic boom body 13, As shown in 15 (f), the lift 16
Moves horizontally to one side (rightward in FIG. 15) of the vehicle body 1, and the extension wire 56 is pulled out longer than the length of the extension wire 62. Therefore, since the two winding drums 60 and 67 have the same number of rotations, the support shaft 74 of the winding drum 67 is moved leftward in FIG. 10 along the length direction of the elongated holes 75 and 76. To be Therefore, the interval between the winding drums 60 and 67 is reduced to the length L-S which is closer to the normal interval L by S. Then, the contact plate 83 inserted through the support shaft 74 comes into contact with the limit switch 84, and notifies that the lift 16 is displaced to one side of the vehicle body 1. When the limit switch 84 is operated, the signal from the correction circuit 102 is transmitted to the electromagnetic coil of the synchronous valve 97 via the switching piece 105 and the fixed contact 107. Therefore, the synchronous valve 97 is electrically connected to form a bypass circuit outside the throttle valve 95, and the hydraulic pressure from the hydraulic pump 91 directly flows to the hydraulic cylinder 9 without passing through the throttle valve 95. Then, the amount of hydraulic pressure supplied to the hydraulic cylinder 9 becomes larger than the amount of hydraulic pressure supplied to the hydraulic cylinder 50, and the expansion speed of the hydraulic cylinder 9 becomes faster than the expansion speed of the hydraulic cylinder 50. Therefore, the speed of raising and lowering the telescopic boom body 13 by the hydraulic cylinder 9 becomes faster than the speed of extension of the telescopic boom body 13 by the hydraulic cylinder 50, and the lifting platform 16 is corrected so as to move horizontally to the left in FIG. It Then, when the extension wire 62 is further pulled out and becomes equal to the extension length of the extension wire 56, since the rotation speeds of the winding drums 60 and 67 are the same, the winding drum 67 follows the elongated holes 75 and 76 in FIG. It moves to the right and returns so as to eliminate the deviation S. As a result of this restoration, from FIG.
In the state of (d), the contact plate 83 causes the limit switch 8
4, the synchronous valve 97 is closed and hydraulic pressure is supplied to the hydraulic cylinder 9 via the throttle valve 95.

As described above, the horizontal displacement of the winding drum 67 is detected by the contact plate 83 and the limit switches 84 and 85, and the interval between the winding drums 60 and 67 is always maintained at a predetermined amount L, The lift table 16 can be always lifted vertically upward with respect to the vehicle body 1. The deviation of the hoisting drum 67 is the deviation of the lift table 16 in the horizontal direction with respect to the vehicle body 1. By detecting this deviation and controlling the two synchronous valves 96 and 97, the lift table 16 is moved. It will be lifted vertically upward with respect to the vehicle body 1. From another perspective, two stretch wires 5
In order to keep the lengths of both 6 and 62 equal to each other so that they are always X-shaped, the extension speeds of the two hydraulic cylinders 9 and 50 are alternately controlled to vertically lift the lift table 16 in a straight line. It can be carried out.

In this way, the lift base 1 reaches the predetermined height position.
If 6 is raised, the control valve 93 is closed by returning the lever 99 to the neutral position, and the hydraulic cylinders 9, 18,
No pressure oil is supplied to 50, and the lift table 16 is held at that height position and stops.

<Synchronization of contraction and lowering of the telescopic boom body 13>

Next, even when the lift table 16 is lowered, the lift table 16 must always be lowered in a straight line with respect to the vehicle body 1. If only the retracting speed of the telescopic boom body 13 is operated fast or only the return of the tilt angle is returned quickly, the position of the center of gravity of the lifting platform 16 is biased to one side or the other side of the vehicle body 1, causing the lifting platform 16 to fall.

First, when the descending operation is performed by the lever 99, the signal is transmitted from the controller 98 to the descending instruction circuit 101, and the signal of this descending instruction circuit 101 is transmitted to the electromagnetic coil on the opposite side of the control valve 93. The control valve 93 is reversely connected. Therefore, the pressure oil from the hydraulic pump 91 is transmitted to the hydraulic cylinders 18, 50, and the hydraulic cylinders 9, 18, 50
Acts to reduce each. Further, the signal of the descending instruction circuit 101 is also transmitted to the motor 89 and the switch 104. Therefore, the motor 89 is operated to move the hoisting drum 60 through the sprocket wheel 88, the chain 87, the sprocket wheel 86, and the support shaft 72.
The tension wire 60 is urged in the counterclockwise direction of 0 and the extension wire 60 is wound up by the winding drum 60. The rotation of the support shaft 72 is transmitted to the winding drum 67 via the sprocket wheel 77, the chain 79, the sprocket wheel 78, and the support shaft 74, and the winding drum 67 is driven in synchronization with the rotation speed of the winding drum 60. From this, the winding drum 60 and the winding drum 67 respectively wind the stretching wires 56 and 62 at the same speed. Then, the switching piece 105 in the switching device 104 contacts the fixed contact 108, and the switching piece 106 contacts the fixed contact 110.

As described above, since the control valve 93 is closed in the reverse direction, the hydraulic cylinder 50 operates so as to reduce its length, and the telescopic boom body 13 is reduced in length. Further, when the hydraulic cylinders 18 and 19 are contracted, the elevating table 16 is kept horizontal and the telescopic boom body 1 is maintained.
The tilt angle of 3 is gradually rocked so as to make the elevation angle shallower, and the tilt angle of the tilt angle becomes closer to horizontal. In this case, when the hydraulic cylinder 9 is contracted, the lower boom 6 rotates about the pin 7 and is rotated clockwise in FIGS. 1 and 4, and the telescopic boom body 13 is brought close to horizontal.

In this operation, in order for the lift 16 to descend vertically downward with respect to the vehicle body 1, the lengths of the two extension wires 56 and 62 must always be the same. However, unlike the above-described pulling operation, the extension wires 56 and 62 themselves do not shrink, but the motor 89 is operating and the sprocket wheel 88,
Since the support shaft 72 is urged to rotate via the chain 87 and the sprocket wheel 86, the winding drum 60 pulls the extension wire 56 with an appropriate tension and does not loosen the extension wire 56. As the support shaft 72 rotates, the sprocket wheel 77 and the chain 7
9. The support shaft 74 is also simultaneously rotated via the sprocket wheel 79, and the winding drum 67 also urges the extension wire 62 to always pull the extension wire 62 with an appropriate tension. In this way, the two extension wires 56, 62 are always in a pulled state and maintain the X shape.

In this state, if the reduction amount of the hydraulic cylinder 50 becomes faster and the reduction speed of the telescopic boom body 13 becomes faster than the reduction speed of the elevation angle caused by the hydraulic cylinder 9, the lifting platform 16 moves to the left in FIG. When the extension wire 56 is moved in the direction, the extension wire 56 is wound more than the extension wire 62, and the extension lengths of the extension wires 56 and 62 differ from each other. Therefore, as shown in FIG. 15 (e), the support shaft 74 of the winding drum 67 is moved along the elongated holes 75 and 76, and the distance between the winding drums 60 and 67 is L +.
It becomes S. Then, the contact plate 83 inserted through the support shaft 74
Activates the limit switch 85, and the correction circuit 103
Signal to. The output signal of the correction circuit 103 is transmitted to the tuning valve 97 via the switching piece 106 and the fixed contact 110 to make the tuning valve 97 conductive. Therefore, the throttle valve 9
By virtue of the formation of the bypass circuit in 5, the pressure oil from the hydraulic pump 91 is directly supplied to the hydraulic cylinders 9 and 18, and the reduction speed thereof is accelerated. When the hydraulic cylinder 9 is reduced in contraction speed, the tilt angle of the telescopic boom body 13 is drastically lowered, and the lifting platform 16 is moved to one side (rightward in FIG. 15) of the vehicle body 1 as shown in FIG. The lift 16 returns to the state shown. Then, the winding amount of the extension wire 62 becomes larger than the winding amount of the extension wire 56, and the rotation amounts of the winding drums 60 and 67 are the same.
5 and 76 are moved toward the winding drum 60. Then, the contact plate 83 inserted into the support shaft 74 is separated from the limit switch 85, and the signal from the correction circuit 103 is stopped, so that the tuning valve 97 is closed and the hydraulic cylinder 9,
The pressure oil that has passed through the throttle valve 95 is supplied to 18, and the reduction speed is reduced.

When the hydraulic cylinders 9 and 18 have a high reduction speed and the hydraulic cylinder 50 has a low reduction speed, the lift 16 moves horizontally to one side of the vehicle body 1 as shown in FIG. It will be. In such a state, the extension length of the extension wire 56 is the extension wire 6
It is longer than the overhanging length of 2. However, since the winding drum 67 around which the stretching wire 62 is wound and the winding drum 60 around which the stretching wire 56 is wound have the same rotation speed, the support shaft 74 holding the winding drum 67 has the long holes 75 and 76. Along the direction toward the winding drum 60. Therefore, the distance between the winding drums 60 and 67 becomes LS, and the distance is reduced, so that the contact plate 83 is reduced.
Comes into contact with the limit switch 84. When the limit switch 84 is operated, the signal generated from the correction circuit 102 is transmitted to the electromagnetic coil of the tuning valve 96 via the switching piece 105 and the fixed contact 108 to make the tuning valve 96 conductive. Therefore, a bypass circuit is formed in the throttle valve 94, the pressure oil supplied from the hydraulic pump 91 to the hydraulic cylinder 50 is accelerated, and the reduction speed of the hydraulic cylinder 50 is accelerated. For this reason, the speed at which the length of the telescopic boom body 13 is reduced becomes faster, and the lifting platform 16 is moved horizontally to the left in FIG. 15 to return to the normal state shown in FIG. When the length of the telescopic boom body 13 is reduced quickly, the speed at which the extension wire 56 is retracted is increased, and the extension wire 56 is corrected to approach the length of the extension wire 62. Therefore, the distance between the hoisting drums 60 and 67 returns to the length L, the contact plate 83 inserted into the support shaft 74 is separated from the limit switch 84, and the signal from the correction circuit 102 is transmitted to the tuning valve 96. The tuning valve 96 will be closed. Then, the hydraulic pump 91 to the hydraulic cylinder 50
The amount of hydraulic pressure supplied to the valve becomes the previous pressure that has passed through the throttle valve 94, and the reduction speed of the hydraulic cylinder 50 decreases.

In this way, the contact plate 83 alternately contacts the limit switches 84 and 85, and the two tuning valves 96 and 9 are connected.
By controlling 7, two stretch wires 56, 6
The overhang lengths of 2 are always corrected to be equal. As a result, the tip of the telescopic boom body 13 descends in a straight line perpendicular to the vehicle body 1, and the elevating table 16 descends straight downward while maintaining the horizontal position.

[0068]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the two extension wires extending in the X-shape between the vehicle body and the lifting platform are provided with two systems of the elevating means of the telescopic boom and the telescopic means. The deviation can be detected and corrected by the difference of
Therefore, it is possible to raise or lower the lift table vertically upward with respect to the vehicle body with a simple configuration for detecting deviation. If it is attempted to control the vertical movement of this lifting platform accurately with a device such as a computer, expensive angle sensors and extension sensors must also be used, and the overall device becomes extremely expensive. It can be manufactured at extremely low cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a lifting platform of a lifting device is raised to a maximum height.

FIG. 2 is a side view showing a state in which a lifting table of the lifting device is lowered to a lowermost position.

FIG. 3 is a front view showing a state in which a lifting platform of the lifting device is lowered to a lowermost position.

FIG. 4 is a side view showing a state in which the lifting platform of the lifting device is lifted to the maximum height.

FIG. 5 is a side view showing an internal configuration of a telescopic boom body of the lifting device.

6 is a cross-sectional view of the telescopic boom body taken along the line AA in FIG.

7 is a cross-sectional view of the telescopic boom body taken along the line BB in FIG.

FIG. 8 is a cross-sectional view showing the vicinity of a roller attached to the tip boom of the telescopic boom body.

FIG. 9 is a side sectional view showing the configuration of a follow-up detection mechanism used in the lifting device.

FIG. 10 is an exploded perspective view showing a main part of a follow-up detection mechanism used in the lifting device.

FIG. 11 is a hydraulic circuit diagram showing a hydraulic control system in the lifting device.

FIG. 12 is an explanatory view showing the operation of the telescopic boom body in a contracted state.

FIG. 13 is an explanatory view showing the operation of the telescopic boom body, showing the middle of the telescopic process.

FIG. 14 is an explanatory diagram of the extended state showing the operation of the telescopic boom body.

FIG. 15 is an explanatory view showing the position correction of the lifting table with the extension wire.

[Explanation of symbols]

 1 Body 6 Lower Boom 9 Hydraulic Cylinder 10 Middle Boom 11 Tip Boom 12 Cover Body 13 Telescopic Boom Body 18 Hydraulic Cylinder 50 Hydraulic Cylinder 56 Stretching Wire 60 Winding Drum 62 Stretching Wire 64 Winding Drum 68 Follower Detecting Mechanism 72 Spindle 74 Spindle 77 Sprocket wheel 78 Sprocket wheel 79 Chain 84 Limit switch 85 Limit switch

Claims (1)

[Claims] 1. A movable vehicle body, a flat lifting platform arranged above the vehicle body, and a telescopic boom body disposed between the vehicle body and the lifting platform and having a plurality of booms inserted in its length direction.
The body and the lifting platform are composed of a lifting means that is interposed between the vehicle body and the telescopic boom body and that can lift the telescopic boom body diagonally, and an extending means that is housed inside the telescopic boom body and extends the telescopic boom body. And a telescopic boom body are arranged so as to have a Z-shape when viewed from the side, and an elevating device capable of vertically moving the elevating platform by expanding and contracting the telescopic boom body and raising the elevating platform is provided. Connect the ends of one stretch wire, wind the first stretch wire around the first winding drum on the other side of the vehicle body,
The tip of the second extension wire is connected to the other lower surface of the lifting platform, the second extension wire is wound around the second winding drum on one side of the vehicle body, and either one of the winding drums is rotatably supported. Then, one of the other winding drums is held so as to be freely rotatable and movable in the horizontal direction, and the deviation of the withdrawal amounts of the first and second extension wires is detected by the moving amount of the other winding drum. An elevating device, characterized in that the elevating means and the elongating means are controlled to control the elevating table so that the tip end of the telescopic boom moves vertically with respect to the vehicle body while keeping the elevating table horizontal.