JPS5932399B2 - Method and device for controlling the extension and contraction of booms for working at high places - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and device for extending and retracting a multi-stage telescopic boom suitable for work where there is a risk of electric shock, such as work on high-voltage power lines. When extending, first, only the most advanced boom is extended by a certain length and then the extension movement of the subsequent part is started, and when the extending boom is to be shortened, the first most extended boom is extended by a certain length. The boom is characterized in that other parts are shortened while maintaining the same, and after the other parts have finished being shortened, the most advanced boom is shortened by a certain length.

When working at heights where there is a risk of electric shock, cutting-edge booms are made of insulating material to ensure work safety. However, some insulating booms require the boom to be extended to a certain length in order to provide the specified insulation performance. items that need to be maintained in a
For example, there is an FRP cylinder made of epoxy resin.

In conventional multi-stage telescopic booms, when the boom is extended and retracted, the multiple stages of the boom extend and retract at the same time, but it is not possible to simply extend the boom to a low position.The most advanced insulating boom cannot perform the necessary extension. However, it is an object of the present invention to solve this problem.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings showing the apparatus for carrying out the present invention.

In the figure, the multi-stage telescopic boom A for high-altitude work of the present invention is shown as a three-stage telescopic boom mounted on the high-altitude work vehicle B, and the base end of the first (base end) boom on the outside is connected to the work vehicle. swivel base C
It is supported by a shaft so that it can be raised and raised freely, and is raised and lowered by the expansion and contraction of the elevation cylinder D.

The telescopic boom consists of a second (intermediate) boom 2 and a leading edge (third) boom 3 that are fitted in sequence to the first boom 1 in a telescopic manner, and the leading edge boom 3 is an insulating boom made of an insulating material. A workbench E is pivotally supported on the tip of the boom.

The most advanced boom 3 cannot obtain sufficient insulation performance unless it is extended to a certain length from the shortened state shown in FIG. 1.

The boom telescoping device of the present invention includes a main telescoping cylinder device 4 whose base end is pivotally supported at the base of the first boom 10 by a pin 41, as shown in FIG.

The main telescopic cylinder device 4 of the embodiment, as shown in detail in FIG. The portion 430 near the base end is pinned to the base end of the second boom 2 by a pin 44 (Fig. 2).The second boom 2 expands and contracts with respect to the first boom 1 by the expansion and contraction of the main cylinder device 4. do.

In FIG. 3, 45 is a piston, 46 and 47 are an elongated conduit and a shortened conduit provided on the piston rod, respectively, and the liquid feeding tube 74.
and 76 (FIG. 2), and 48 is a roller that facilitates relative movement between the leading edge boom 3 and the cylinder portion 43.

The boom interlocking device, generally indicated by the reference numeral 5 in FIG.
One of the wires 51 of No. 1 and 52 is led to the base end of the most advanced pool 30 through the second boom tip guide sheave 53, and the other wire 52 is guided through the guide sheave 54 at the base end of the second boom (to the most advanced pool 30). When the main cylinder device 4 is extended and contracted to extend and retract the second boom 2 with respect to the fourth boom using a known interlocking device that is guided to the proximal end and whose tips are both tied 55 to the proximal end, The most advanced boom 3 is also moved by the same amount and in the same direction relative to the second boom 2.

Although only one side of the interlocking device 5 is shown in FIG. 2, it is preferable to install similar devices on both sides of the telescoping boom to ensure smooth operation.

In the device of the present invention, the two interlocking wires 5L
520 base end 50 is not tied to the first boom, but is tied to the tip (slide base) 61 of the telescopic part of the sub-cylinder device 6 fixed near the tip of the fourth boom 1. .

The sub-cylinder device 6 of the embodiment is mounted on the outside of the first boom, and the base ends of the two interlocking wires are drawn out through a slit-shaped opening 11 provided at the tip of the first boom.
They are individually connected to brackets 62 and 63 provided on the slide base 61.

Reference numerals 56 and 57 indicate guide sheaves provided before and after the opening 11.

The auxiliary cylinder device 6 may be provided separately for each boom interlocking device on both sides, but it is also possible to drive both devices with one unit.

The secondary cylinder assembly 6 of the embodiment is shown as being in an extended state when the leading edge boom 3 is in its fully retracted state as in FIG.

When the auxiliary cylinder device is shortened, only the most advanced boom 3 is extended by a certain length, regardless of the movement of other cylinders.

In the illustrated example, the extension/retraction stroke of the sub-cylinder device is equal to the amount of extension/retraction of the most advanced boom, but it is easy to increase the amount of extension/retraction with an appropriate pulley device.

The stroke of the auxiliary cylinder device is the length required for the most insulating boom to obtain a predetermined insulation performance, and this portion will hereinafter be referred to as the ``specified extension portion.''

) is made to be extended and terminated.

Therefore, when the secondary cylinder reaches the shortened stroke end, sufficient insulation is obtained for use in high voltage work on the workbench.

In high-place work, the extension of the main cylinder device 4 is started after the boom extension stroke of the sub-cylinder device is completed.

When the main cylinder device 4 is extended, the second multi-stage telescopic boom
As mentioned above, the third (most advanced) boom extends all at once.

When shortening the boom, first the main cylinder device 4 is shortened.

With this operation, the second and third (most advanced)
The booms begin to shorten all at once, but the secondary cylinder device is not activated, so the most advanced boom maintains its specified extension, and insulation performance is still maintained.

As is clear from the above description, the present invention has the effect of allowing work to be carried out at any height within the range where the most advanced boom can be extended to a specified length.

When retracting the boom, after the main cylinder device has moved to the farthest end, the sub-cylinder device is operated to shorten the prescribed extension portion of the most end boom.

In order to avoid errors in the operating order of the main cylinder device and the sub-cylinder device, it is easy to provide safety measures such as locking the main cylinder device while the specified extension portion of the most advanced boom is not fully extended. However, FIG. 4 shows a cylinder control device configured so that a predetermined sequence of operations can be automatically obtained.

Fig. 4 shows a hydraulic circuit that operates both cylinder devices with hydraulic pressure, and in the sequence control circuit generally designated by 7, 70 is an oil reservoir, 71 is an oil pump, and 72 is a pressure oil This is a 6-port operation valve with 3 positions: extended position a of the main cylinder device, neutral position b, and shortened position C of the main cylinder device.

Extension side oil feed pipe 73 supplied with pressure oil at extension position a
is directly connected to the boom extension (cylinder device shortening) side of the auxiliary cylinder device 6, and an extension side branch pipe 74 branched from this is connected to the extension pipe line 46 of the main cylinder device 4 via the first sequence valve 75.

On the other hand, the shortening side sending heavy pipe 76 to which pressure oil is supplied in the shortening position C is directly connected to the shortening pipe line 47 of the cylinder device 4, and the shortening side branch pipe 71 branched from this is connected via the second sequence valve 78. Connect to the boom shortening (cylinder device extension) side of the sub-cylinder device.

FIG. 4 shows the boom in its most retracted state as shown in FIG.

In a device equipped with the hydraulic circuit configured as described above, when the operation valve 72 is operated to switch to the extension position a in order to extend the boom, pressure oil is first sent to the sub cylinder device 6 to extend the most advanced boom.

When the constant extension portion of the most advanced boom extends, the sub-cylinder device reaches the stroke end and the oil pressure in the extension-side oil feed pipe 73 increases, so the first sequence valve 75 is operated and the main cylinder device 4 starts to extend.

When the operating valve is switched to the shortening position C, pressure oil is sent directly to the main cylinder device through the shortening side oil feed pipe 76 to shorten the boom.

When the main cylinder device reaches the shortened stroke end, the oil feed pipe 7
6 increases and operates the second sequence valve 78.

As a result, the secondary cylinder device 6 is actuated to shorten the prescribed extension portion of the most advanced boom.

By providing such a sequence device, the series of sequence operations described above can be automatically performed simply by operating the operating valve 72, which has the effect of eliminating the possibility of making a mistake in the order of operations.

Although the sub-cylinder device shown in the figure extends the most advanced boom by shortening it, it goes without saying that the same effect can be obtained even if the reverse is the case.

[Brief explanation of the drawing]

FIG. 1 is a side view of an aerial work vehicle for implementing the present invention, FIG. 2 is a vertical side view showing an example of a boom for implementing the method of the present invention, and FIG. 3 is a vertical cross-sectional view of the main cylinder device. , FIG. 4 is a hydraulic circuit diagram of the sequence control device. A=multistage telescopic boom, C=swivel base, 1=first boom, 2
2-Second boom, 3-Most advanced boom, 4=Main cylinder device, 5=Boom interlock device, 6=Sub-cylinder device, 7=Sequence disease control circuit.

Claims (1)

[Scope of Claims] 1. In the telescopic control of the multi-stage telescopic boom, in the case of boom extension, first the predetermined extended part of the most advanced boom 3 is extended, and then the extension movement of other parts of the multi-stage telescopic boom is started. . A method for controlling the extension and contraction of a boom for working at high places, in which, when shortening the boom, other parts are shortened while maintaining the extension of the specified extension part, and after shortening of the other parts is completed, the specified extension part is shortened. 2 A main telescopic cylinder device 4 and a boom interlocking device 5 that expands and contracts the multistage boom all at once by expanding and contracting the main telescopic cylinder device.
In a multi-stage telescopic boom having a multi-stage telescopic boom, the base end of the movement wires 51, 520 of the boom interlocking device is tied to the slide base 61 of the sub-cylinder device 6 that extends and contracts only the prescribed extension portion of the most advanced boom 3. Boom telescoping device.