JPH047799B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a safety device for an excavator for expanding the bottom of a pile hole, which is used when constructing foundation work such as cast-in-place piles in civil engineering, construction work, etc. It is something.

(Prior art) This type of excavator for expanding the bottom of pile holes includes, for example,
There is a split bucket type rotary excavation device (Japanese Patent Laid-Open No. 60-242292) that was previously filed by the present applicant.

(Problems to be solved by the invention) However, the above-mentioned device (Japanese Patent Laid-Open No. 60-242292
No.) has one hydraulic cylinder that opens and closes each cutter unit of the divided bucket as shown in Figure 2.
For example, if a hydraulic hose breaks during bottom-expanding work and the cutter unit cannot be retracted, it becomes impossible to raise the bucket and the work is interrupted. Ta.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the present invention, a bucket-type excavator having a cutter that can be expanded and contracted is installed at the lower end of a rotary shaft that can be raised and lowered, and the excavated pile In the excavator for expanding the bottom of a pile hole, the bucket-type excavator is expanded and rotated and lowered into the hole to form an expanded hole, and two hydraulic cylinders for expanding and contracting the cutter are arranged in parallel. In addition, a hydraulic supply system for cutter contraction operation is provided independently for each hydraulic cylinder, and a stop valve is provided in each of these systems to constitute a safety device for an excavator for expanding the bottom of a pile hole.

(Function) As described above, in the present invention, two hydraulic cylinders are used for expanding and contracting the cutter of the excavator for expanding the bottom of a pile hole.
In addition to providing this in parallel, a hydraulic supply line for cutter contraction operation is provided independently for each hydraulic cylinder.
Since a stop valve is provided in each of these lines, even if one of the hydraulic hoses is cut during bottom expansion work, the stop valve of the cut oil line will be closed and the remaining oil line will be used to expand the line. By contracting the cutter that is
A bucket excavator can be pulled out of a pile hole.

Therefore, according to the present invention, even if one of the oil passages breaks down during construction, there is no fear that the construction will be interrupted for a long time.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In the figure, 1 is the ground, 2 is the pile hole formed in the ground 1,
3 is a crawler crane, 4 is its crawler, 5 is a swivel base provided on the crawler 4 so as to be freely swivelable, 6 is a crane boom attached to the swivel base 5 so that it can be raised and lowered, and 7 is the tip of the crane boom 6 (not shown). figure)
Kelly bar (rotating shaft) that can be raised and lowered freely,
8 is a support member that supports the lower part of the Kelly bar 7; 9
1 is a rotational drive device for the Kelly bar 7 provided on the support member 8, 10 is a connecting arm that connects the support member 8 and the swivel base 5, and 11 is a rotary joint (rotary joint for a hydraulic circuit) provided below the support member 8. , 12
13 is a cable reel provided below the rotary joint 11, 14 is a wire reel, 15 is a hose reel, and 16 is a joint 17 at the lower end of the Kelly bar 7.
18 is a stabilizer (guiding member) attached to the upper part of the main post 16, 19 is a lifting post slidably fitted to the main post 16, and 20 is a main post 16 This is a bucket-type excavator installed at the bottom of the excavator 20. As shown in FIGS. The cutter units 20a, 20b, 20c, and 20d are configured to be able to expand and contract via link mechanisms 21, respectively.

That is, each cutter unit 20a, 20b,
20c, 20d and the lifting post 19 are connected by an upper link 21a and a lower link 21b which are parallel to each other, and the intermediate point of the lower link 21b and the lower end of the main post 16 are connected by the link 21b.
It is connected by a link 21c having a length of 1/2 of
The intermediate point of a is connected by a link 21d. In addition, 22 and 23 are brackets for link connection protruding from the lifting post 19, 24 are brackets protruding from the lower end of the main post 16, and 25, 26.
are each cutter unit 20a, 20b, 20c,
Brackets 20d project from each other, and 27 is a pin for connecting each link.

In this embodiment, hydraulic cylinders 28 and 29 are respectively attached to both sides of the main post 16 below the stabilizer 18 via a shaft 30 and a bracket 31 with the piston rods 28a and 29a facing downward.
The lower ends of the vertical members are connected to a horizontal member 34 via a clevis 32 and a pin 33, respectively, and the horizontal member 34 is connected to the main post 16 by passing through a vertical groove (not shown) provided in the elevating post 19. It is fixed to the post 16.

Therefore, by raising and lowering the piston rods 28a and 29a of the hydraulic cylinders 28 and 29, the lifting post 19 can be moved up and down with respect to the main post 16, and each cutter unit of the bucket excavator 20 can be expanded or contracted. I can do it.

FIG. 3 shows that the elevating post 19 is moved to the main post 16 by extending the hydraulic cylinders 28 and 29.
4 shows a state in which the bucket-type excavator 20 is contracted by the action of the link mechanism 21. Conversely, FIG. This shows the open state.

Furthermore, in this embodiment, as shown in FIG.
Three hose reels 15a, 15b, 15c are provided below the rotary joint 11, and one oil path 35 connected to the rotary joint 11 is connected to the
A stop valve 37 is interposed in the middle of one of the branched oil passages 36, and this oil passage 36 is connected to a hose 38 of the hose reel 15a, and this hose 38 is connected to the upper chamber of the hydraulic cylinder 28. Connect to.

Further, a stop valve 40 is interposed in the middle of the other branched oil passage 39, and this oil passage 39 is connected to a hose 41 of the hose reel 15b, and this hose 41 is connected to the upper chamber of the hydraulic cylinder 29.

Also, the other oil passage 42 connected to the rotary joint 11 is connected to a hose 43 of the hose reel 15c, and this hose 43 is connected to the hydraulic cylinders 28, 2.
9 lower chambers respectively.

Note that 44 and 45 are oil passages for supply and discharge provided between the pressure oil supply device and oil storage device (not shown) and the rotary joint 11.

Next, the operation of the apparatus of the present invention constructed as described above will be explained. To widen the bottom of the pile hole 2 with this excavator, as shown in FIG. The bucket type excavator 20 is lowered, and the bucket type excavator 20 is lowered as shown in FIG.
After reaching a predetermined position, the Kelly bar 7 is rotated and lowered by the rotary drive device 9, and hydraulic pressure is applied via the rotary joint 11, oil passage 42, and hose 43 as shown in FIG. By supplying pressure oil to the lower chambers of the cylinders 28, 29 and lowering the cylinders 28, 29 relative to the piston rods 28a, 29a, the elevating post 19 is lowered relative to the main post 16, and via the link mechanism 21, the bucket Each cutter unit of the mold excavator 20 is gradually expanded. In this way, the bottom of the pile hole 2 can be finally enlarged as shown in FIG. 4.

Once this bottom widening work is completed, pressure oil is supplied to the upper chambers of the hydraulic cylinders 28, 29 via the oil passages 35, 36, 39 and hoses 38, 41 shown in FIG. By raising the bucket excavator 2 via the link mechanism 21
0 was contracted as shown in FIG. 3, and then the bucket-type excavator 20 was pulled up from the pile hole 2 by raising the Kelly bar 7.

In this case, with conventional equipment, if the hydraulic hose for contracting the bucket is cut, for example, the expanded bucket becomes unable to contract and cannot be pulled out of the pile hole 2, so construction must be stopped for a long time. It was impossible.

However, in the present invention, there are two hydraulic supply lines for the bucket contraction operation, such as the hoses 38 and 41, so even if one hose 38 is disconnected, the stop valve 38 of that system
By closing 7, the bucket can be deflated by the remaining hose 41.

(Effects of the Invention) As described above, in the present invention, two hydraulic cylinders are used for expanding and contracting the cutter of the excavator for expanding the bottom of a pile hole.
In addition to providing this in parallel, a hydraulic supply line for cutter contraction operation is provided independently for each hydraulic cylinder.
Since a stop valve is provided in each of these lines, even if one of the hydraulic hoses is cut during bottom expansion work, the stop valve of the cut oil line will be closed and the remaining oil line will be used to expand the line. By contracting the cutter that is
A bucket-type excavator can be easily pulled up from a pile hole.

Therefore, according to the present invention, an excellent effect can be obtained in that even if one of the oil passages breaks down during construction, there is no fear that the construction will be interrupted for a long time.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the device of the present invention, and FIG. 2 is a partial elevational view of an excavator for expanding the bottom of a pile hole to which the present invention is applied.
Figure 3a is an elevational cross-sectional view showing the excavator suspended in the pile hole in a contracted state, Figure b is a bottom view of the bucket part, and Figure 4a is the state at the end of the bottom expansion work of the pile hole. An elevational cross-sectional view, and Figure b is a bottom view of the bucket part. DESCRIPTION OF SYMBOLS 1... Ground, 2... Pile hole, 3... Crawler crane, 6... Crane boom, 7... Kelly bar, 8... Support member, 9... Rotation drive device, 10
...Connection arm, 11... Rotary joint, 12... Rotating table, 15 (15a, 15b, 1
5c)... Hose reel, 16... Main post, 18... Stabilizer, 19... Lifting post, 20... Bucket type excavator, 21... Link mechanism, 28, 29... Hydraulic cylinder, 35, 36
...oil line, 37...stop valve, 38...hose, 39...oil line, 40...stop valve,
41...Hose, 42...Oil line, 43...Hose, 44, 45...Oil line.

Claims (1)

[Claims] 1. A bucket-type excavator with a cutter that can be expanded and contracted is installed at the lower end of a rotary shaft that can be raised and lowered, and the bucket-type excavator is expanded and lowered while rotating into the excavated pile hole to create a bottom-expanded hole. In the excavator for expanding the bottom of pile holes, two hydraulic cylinders for expanding and contracting the cutter are provided in parallel, and a hydraulic supply line for operating the cutter retracting is provided independently for each hydraulic cylinder. A safety device for an excavator for expanding the bottom of a pile hole, characterized in that a stop valve is provided in each of these systems.