JPS5935839B2 - Work platform automatic balancing device for aerial work vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an aerial work vehicle in which a work platform is attached to the tip of a two-stage telescoping boom device that can be raised and lowered, and that the work platform is always fixed regardless of the extension and contraction of the boom device and the raising and lowering operations. This invention relates to an automatic balancing device for the work platform of an aerial work vehicle, which is maintained horizontally and balanced.

The work platform of an aerial work vehicle must be kept horizontal and balanced at all times, as it is used by workers to perform various tasks and also contains the various work tools necessary for the work. need to be

As described above, the workbench automatic balancing device for holding the workbench horizontally has one side of the workbench pivoted to the tip of the boom device, and a device that automatically balances the workbench using a cable such as a rope. Make sure that tension is applied in the direction,
It has been considered that the rope can be expanded and contracted in accordance with the movement of the boom device, such as expansion and contraction and raising and lowering.

A work platform automatic balancing device using such a pulley device can be simple and lightweight in structure, and can be applied to systems where the boom device performs both telescopic and up-and-down operations. The present invention is desirable as an automatic work platform balancing system for devices such as aerial work vehicles, where the weight and length of the mounted boom device are limited.

However, the conventional work platform automatic balancing device using a pulley device is unable to extend or contract the rope exactly corresponding to the lifting angle, especially when the boom device is raised or lowered.
Because the rope was made to expand and contract approximately, for example, when the inclination angle of the boom device became large, the rope could become loose or become too tense, causing the work platform to tilt. Ta.

Furthermore, the rope may obstruct the operation of the boom device,
There was also a risk that the rope would break if it was forced to operate.

In addition, in conventional work platform automatic balancing devices using pulley devices, the tension applied to the work platform by the rope is only in one direction, and the work platform is balanced by balancing this tension with the work platform's own weight. As a result, the workbench would sometimes sway when the worker moved on it.

In addition, if the work platform comes into contact with a structure when the boom device is lowered, and an external force is applied to the work platform in a direction that resists its own weight, the work platform may tilt or even tip over. Ta.

In view of the above-mentioned points, the present invention maintains the work platform in a horizontal state at all times regardless of the extension/contraction and raising/lowering operations of the boom device, and maintains the horizontal state even when the work platform is subjected to external force in any direction. The main object of the present invention is to provide an automatic work platform balancing device for an aerial work vehicle using a pulley device, in which the work platform of an aerial work vehicle is reliably held.

Another object of the present invention is to provide an elevated platform using a pulley system in which a flexible cord, such as a rope, extends and contracts exactly the length to ensure that the work platform is leveled during the extension and retraction and hoisting operations of the boom system. An object of the present invention is to provide an automatic balancing device for a work platform of a work vehicle.

Still another object of the present invention is to always apply tension of equal magnitude to the workbench from two opposing directions by means of flexible cables;
An object of the present invention is to provide an automatic work platform balancing device for an aerial work vehicle using a pulley device, whereby the work platform is held in balance.

According to the present invention, the base boom of the two-stage telescopic boom device is connected to the vehicle body at the pivot point and the front end of the tip boom is connected to the workbench at the pivot point, respectively, as the boom device moves up and down. A base and a tip fixed pulley of the same diameter are attached to rotate relatively to the base boom, and first and second fixed pulleys are attached to the tip of the base boom and the base of the tip boom, respectively. A movable pulley is provided between the fixed pulley and the second fixed pulley, and the base cable, which is fixed at both ends to the tip boom, is connected to the fixed pulley at the base and the first fixed pulley.
The hook is passed to the fixed pulley and the movable pulley, and it is also attached to the base fixed pulley, and the tip rope, which has both ends fixed to the base boom, is passed to the fixed pulley, the second fixed pulley, and the movable pulley. At the same time, it also attaches to the fixed end pulley, thereby locking the work platform by always applying equal tension from two directions facing the fixed end pulley fixed to the work platform, and fixing the base when the boom device is raised or lowered. The fixed pulley at the tip rotates by an angle equal to the relative rotation angle of the pulley to hold the work platform accurately horizontally, and when the boom device is extended or retracted, the movable pulley moves to maintain each cable in tension. , an automatic work platform balancing device for an aerial work vehicle is obtained.

Hereinafter, the present invention will be described in detail with reference to the drawings. In FIG. 1, a support 2 is erected on the body 1 of an aerial work vehicle, and a pivot shaft 3 is fixed to the upper end of the support 2. .

The two-stage telescopic boom device 4 includes a base boom 5 and a tip boom 6 slidably inserted into the base boom 5, and a base bracket 7 is fixed to the base boom 5.

The base bracket 7 is rotatably supported by the pivot shaft 3.

A pivot shaft 8 is rotatably supported at the tip of the tip boom 6, and the pivot shaft 8 is fixed to a bracket 10 fixed to a workbench 9.

A hydraulic cylinder 11 for luffing is provided between the base boom 5 and the support column 2, and the telescopic boom device 4 rotates around the pivot shaft 3 due to the telescoping operation of this hydraulic cylinder 11, thereby performing the luffing operation. It is designed to do this.

Furthermore, a hydraulic cylinder for telescoping (not shown) is provided between the base boom 5 and the front boom 6, and its telescoping action causes the front boom 6 to move in and out of the base boom 5, allowing it to extend and retract. The boom device 4 is adapted to extend and contract.

A base fixing pulley 12 is provided at the pivot point of the telescopic boom device 4 to the support column 2 .

This base fixed pulley 12 is fixed to the pivot shaft 3.

Since the pivot shaft 3 is fixed to the column 2, the base fixing pulley 12 is fixed to the column 2 after all.

Therefore, when the telescopic boom device 4 moves up and down at an arbitrary angle, the base fixed pulley 12 rotates relative to the telescopic boom device 4 by the same angle.

Further, a tip fixed pulley 13 is provided at the pivot point of the workbench 9 to the telescopic boom device 4.

The tip fixed pulley 13 is fixed to the pivot shaft 8, and the pivot shaft 8 is fixed to the bracket 10 of the workbench 9, so the tip fixation pulley 13 is fixed to the workbench 9 after all. It turns out.

Since the pivot shaft 8 is rotatably supported by the tip boom 6, the workbench 9 can rotate together with the tip fixed pulley 13 relative to the telescopic boom device 4.

An important point of the present invention is that the base fixing pulley 12 and the tip fixing pulley 13 have the same diameter.

In FIGS. 2 and 3, a first fixed pulley 14 is rotatably supported on the inside of the tip of the base boom 5, and a second fixed pulley 15 is rotatably supported on the outside of the base of the tip boom 6. It is pivoted on.

Between these first and second fixed pulleys 14 and 15, a movable pulley guide 16 provided inside the base boom 5 and a movable pulley guide 17 provided outside the tip boom 6 guide the guide. , movable pulley 1 that can move forward and backward (left and right in the figure)
8 is provided.

The movable pulley 18 includes four pulleys 19, 20, 21.22 that are rotatably supported, and these pulleys 19, 20, 21.22 are connected to shafts 23, 23 and links 24.
, 24 so that they move together.

In the illustrated example, two pulleys are supported by two shafts 23.23 and connected by a link 24.24, but if the width of the base boom 5 is sufficiently large, one It is also possible to eliminate the link by placing four pulleys on the book shaft.

Further, in some cases, each pulley may be supported by a separate shaft, and these shafts may be connected by a single link.

As shown in FIG. 4a or FIG. 5a, the base fixed pulley 12, the first fixed pulley 14, and the movable pulley 18 include:
One base cable 25 is attached.

One end of the base cable 25 is fixed to a fastening part 26 provided at the base of the tip boom 6, and after being wrapped around the first pulley 19 of the movable pulley 18, the base cable 25 passes through a guide roller 27 and is attached to the base. Wrapped around a fixed pulley 12 and then another guide roller 2
8, it is wrapped around the first fixed pulley 14, further wrapped around the second pulley 20 of the movable pulley 18, and finally the other end is stopped at the fastening part 29 provided at the tip of the tip boom 6. It is worn.

Further, appropriate portions of the portions that are wrapped around and in contact with the base fixed pulley 12 are fixed to the fixed pulley 12 by fastening pieces 30.

Similarly, as shown in FIG. 4 or 5, the fixed end pulley 13, the second fixed pulley 15, and the moving pulley 1
8, one tip cable 31 is passed through the hook.

One end of the tip cable 31 is fixed to a fixing part 32 provided at the tip of the base boom 5, and after being wrapped around the third pulley 21 of the movable pulley 18, the tip cable 31 passes through a guide roller 33 and then passes through a guide roller 33. The other end is wrapped around the fixed pulley 13, then passed through another guide roller 34, wrapped around the second fixed pulley 15, further wrapped around the fourth pulley 22 of the moving pulley 18, and finally the other end is wrapped around the base boom. It is fastened to a fastening part 35 provided at the base of 5.

The contact portion of the tip cable 31 that is wrapped around the tip fixed pulley 13 is similarly fixed to the fixed pulley 13 at appropriate points by fastening pieces 36.

The base cable 25 and the tip cable 31 are flexible cables such as wires, ropes, chains, etc., but they are preferably cables that do not stretch as much as possible even when tension is applied.

When using a chain, fixed pulleys 12, 13°1
4.15 and each pulley 19,20°21.2 of movable pulley 18
2, a sprocket wheel is used.

Although the base cable 25 and the tip cable 31 have been explained as one cable each, if a cable of sufficient length cannot be obtained, one end can be attached to the base fixing pulley 12 or the tip fixing pulley. It is also possible to provide two cables each attached to 13.

Thus, the hoisting hydraulic cylinder 11 of the telescopic boom device 4
When both the telescopic boom device 4 and the telescopic hydraulic cylinder (not shown) are in operation, there is no relative angular displacement between the telescopic boom device 4 and the base fixed pulley 12 fixed to the column 2, and the base boom There is also no relative positional change between 5 and the front boom 6.

Therefore, when looking at the base cable 25, the fastening portion 26
Since the position of the fastening piece 30 is fixed, the movable pulley 18
cannot move forward (to the left in the figure), and the attachment part 29
Since the position of the fastening piece 30 is fixed, the movable pulley 18
cannot move backwards (to the right in the diagram).

That is, the movable pulley 18 cannot be moved in either direction and is fixed at that position.

On the other hand, when looking at the tip rope 31, the fastening portion 32°35
is fixed and there is no change in the position of the movable pulley 18, so the position of the fastening piece 36 of the fixed end pulley 13 does not change.

Therefore, even if an external force is applied to the workbench 9 in any direction, the tip cable 31 fixed by the fastening piece 36
Since a counter tension is applied by the workbench 9,
is not tilted.

That is, as long as the base cable 25 and the tip cable 31 are tensioned, the work platform 9 is fixed in a constant state and held in equilibrium.

Here, the telescoping hydraulic cylinder (not shown) of the telescoping boom device 4 is activated to move the tip boom 6 forward by a distance l, causing it to protrude from the base boom 5 and extending the telescoping boom device 4. do.

At this time, regarding the base rope 25, as shown in FIG. Since there is no target rotation and the position of the fastening piece 30 does not change, the movable pulley 18 moves forward by a distance of 1/2.

Further, since the fastening portion 26 at the base of the tip boom 6 has also moved forward by a distance l, the movable pulley 18 can move forward by a distance l/2.

Therefore, the movable pulley 18 moves forward by a distance l/2 and is fixed at that position.

On the other hand, looking at the tip cable 31 in this state,
As shown in FIG. 4, since the movable pulley 18 has moved forward by a distance of 1/2, the anchoring portion 3 at the tip of the base boom 5
2 and the fastening piece 36 of the tip fixed pulley 13
1 and base boom 5, and the anchoring piece 36 of the tip fixing pulley 13, the tip cable 31 has a margin of length l, which is exactly this. At this time, the tip fixing pulley 13 supported by the tip boom 6 has also moved forward by a distance l, so the tip cable 31 is maintained under tension.

Moreover, at this time, the tip cable 31 is pulled by the same length on both sides of the anchoring piece 36, so the relative positional relationship of the anchoring piece 36 of the tip fixing pulley 13 with respect to the tip boom 6 changes. do not have.

That is, the workbench 9 fixed to the tip fixed pulley 13 is
Move forward a distance l while maintaining the original horizontal position,
It will be maintained in equilibrium in that state.

When retracting the telescopic boom device 4, the movable pulley 18 moves rearward and is fixed in the opposite direction to the above, whereby the tip cable 31 pulls the fastening piece 36 of the tip fixed pulley 13 from both sides by the same amount. Since it is pulled, the workbench 9 moves rearward in a horizontal state and is held balanced in that state.

Next, the luffing hydraulic cylinder 11 is operated to start the telescopic boom device 4 clockwise, and the angle θ is started from the illustrated position.
If the angle of inclination is larger by (radian), the telescopic boom device 4 rotates clockwise by an angle θ with respect to the base fixed pulley 12 fixed to the column 2.

This is basically the same thing as fixing the telescopic boom device 4 and rotating the base fixed pulley 12 counterclockwise by an angle θ, so for convenience of explanation, FIG. a,
In b, the base fixed pulley 12 is shown as if it had been rotated counterclockwise by an angle θ.

In FIG. 5a, when the base fixed pulley 12 with radius γ rotates counterclockwise by an angle θ, the base fixed pulley 12 rotates counterclockwise by an angle θ.
The base cable 25 is fixed to 2 by the fastening piece 30,
The open side between the base fixed pulley 12 and the attachment part 26 at the base of the tip boom 6 is extended by a length γθ, and the open side between the base fixation pulley 12 and the attachment part 29 at the tip of the tip boom 6 is extended by a length γθ. It is wound up by a length γθ.

At this time, since the tip boom 6 is fixed by a telescopic hydraulic cylinder (not shown), the movable pulley 18 is moved a distance γθ/2 by letting out and winding up the base cable 25.
only moves forward and is fixed in that position.

When the movable pulley 18 moves forward by a distance γθ/2 in this way, as shown in FIG.
The tip cable 31 is fixed to the tip fixing pulley 13 and the fixing portion 35 at the base of the base boom 5 by the fixing piece 36.
The end is pulled by the length γθ on the open side, and the tip fixed pulley 13
and the length γ on the open side of the fastening part 32 at the tip of the base boom 5
It will loosen by θ.

As a result, the tip fixed pulley 13 rotates counterclockwise by an angle necessary to pay out and wind up the tip cable 31 by the length γθ.

The tip fixed pulley 13 has the same diameter as the base fixed pulley 12, and its radius is γ.

Therefore, the tip fixed pulley 13 extends the tip cable 31 to a length γ
The rotation angle when feeding or winding up by θ is θ.

That is, when the movable pulley 18 moves forward by a distance γθ/2, the fixed end pulley 13 rotates counterclockwise by an angle θ and is maintained in equilibrium.

Therefore, when the base fixed pulley 12 rotates counterclockwise by an angle θ, the tip fixed pulley 13 also rotates counterclockwise by an angle θ.
Rotate only.

In other words, when the telescopic boom device 4 rotates clockwise around the base fixed pulley 12 by an angle θ, the work platform 9 fixed to the tip fixed pulley 13 is rotated relative to the telescopic boom device 4. Rotate clockwise by an angle θ.

As a result, the workbench 9 is maintained at its original angle with respect to the base fixing pulley 12 and, therefore, with respect to the vehicle body 1, that is, in a horizontal state.

Even in such a state, both the base cable 25 and the tip cable 31 are maintained in tension, so the workbench 9 is maintained in balance and will not sway or tilt due to external force.

It goes without saying that when the telescopic boom device 4 is rotated counterclockwise and laid down, each pulley device operates in the opposite direction to the above, and the work platform 9 is held horizontally and balanced.

As described above, according to the present invention, when the telescopic boom device 4 is extended or contracted, the movable pulley 18 moves in the front-rear direction by a distance that is half the length of the telescopic boom device 4, so that the base cable 25 and the tip cable 31 is maintained in tension, and the workbench 9 is held in a horizontal and balanced state, and when the telescopic boom device 4 is raised or lowered, the tip fixed pulley 13 is rotated in the opposite direction at an angle equal to the raising or lowering angle. The horizontal state of the workbench 9 is maintained, and each cable 25 and 31 is maintained in a taut state.

In this way, the work platform is always held horizontally and balanced regardless of the extension/contraction and raising/lowering operations of the boom device 4, and the tensioned tip cable 31 is fixed to the tip fixing pulley 13, making it easy to carry out work. Even if an external force is applied to the table 9, the fixed end pulley 13 fixed thereto will not rotate.
Therefore, it is possible to obtain an automatic work platform balancing device for an aerial work vehicle that does not cause the work platform 9 to sway or tilt, and that operates reliably and smoothly.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing an embodiment of an aerial work vehicle equipped with an automatic work platform balancing device according to the present invention, and FIG. FIG. 3 is a cross-sectional side view of the main part showing the embodiment; FIG. 3 is a cross-sectional plan view of the main part of the device shown in FIG. 2; FIG. 4 shows the operation of the telescopic boom device in the device shown in FIG. 2 when it is extended; a is a cross-sectional side view of the main part with the tip cable removed; b is a cross-sectional side view of the main part with the base cable removed; FIG. 5 is the operation of the telescopic boom device in the device shown in FIG. 2 when it is raised and lowered. , in which a is a cross-sectional side view of the main part with the tip cable removed, and b is a cross-sectional side view of the main part with the base cable removed. In the diagram, 1... Vehicle body, 2... Support column, 3...
... Pivot shaft, 4 ... Two-stage telescopic boom device, 5 ... Base boom, 6 ... Tip boom, 8 ...・Pivot shaft, 9...workbench,
12... Base fixed pulley, 13... Tip fixed pulley, 14... First fixed pulley, 15...
...Second fixed pulley, 18...Movable pulley, 19~
22... Pulley constituting the movable pulley 18, 25...
...-base cord, 26 and 29... anchoring part,
30...Fixing piece, 31...Tip rope,
32 and 35... are fastening parts, 36... are fastening pieces.

Claims (1)

[Claims] 1 A pillar 2 erected on the vehicle body 1, a two-stage telescopic boom device 4 consisting of a base boom 5 and a tip boom 6, which are pivotally connected to the pillar 2 so as to be able to rise and fall, and a tip end of the telescopic boom device 4. In an aerial work vehicle equipped with a work platform 9 pivotally attached to a base part;
2; a tip fixed pulley 13 having the same diameter as the base fixed pulley 12, which is attached to the pivot portion of the workbench 9 to the telescopic boom device 4 and fixed to the workbench 9; and the base boom; a first fixed pulley 14 pivotally supported at the tip of the boom 5; a second fixed pulley 15 pivotally supported at the base of the tip boom 6; and between these first fixed pulley 14 and second fixed pulley 15. a movable pulley 18 consisting of a plurality of pulleys 19, 20, 21, 22, which is provided at pulley 18, the base fixed pulley 12, the first fixed pulley 14
, the hooks are sequentially passed to the movable pulley 18, and the other end is fixed to the tip boom 6, and the base cable is also fixed to the fixed pulley 12 at the point of contact with the base fixed pulley 12. One end of 25 is fixed to the base boom 5, and the hook is sequentially passed to the movable pulley 18, the fixed end pulley 13, the second fixed pulley 15, and the movable pulley 18, and the other end is fixed to the base boom 5. 5 and a tip cable 31 fixed to the fixed pulley 13 at a contact point with the fixed pulley 13.