JPH0469718B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides an earth drill in which the front frame is attached to a part other than the boom, such as an earth drill with a telescoping boom. This invention relates to an earth drill front undulation safety device that prevents damage due to contact with the frame or front frame side equipment.

(Prior Art) FIG. 8 shows an example of an earth drill equipped with a telescopic boom 2 in which a plurality of booms are telescopically combined. The front bracket 14 can also be formed as a part of the main body 1.) The boom 2 is attached to the front bracket 14 by a boom hoisting cylinder 4 so as to be able to rise and fall freely around a pin 34. The boom 2 has a built-in telescopic cylinder, and the boom hoisting cylinder 4 is attached between the front bracket 14 and the boom 2. In addition to the hydraulic power source, a hoisting winch 3 is installed on the main body 1.
is a system in which a main hoisting winch and a catch winch are installed side by side, and the Kelly bar 8 is suspended from the main hoisting winch via a main hoisting rope 10a hung over sheaves 37 and 38 at the top of the boom and a swivel joint 39. . An earth drill bucket 9 is attached to the lower end of the Kelly bar 8.

5 is the pin 35 at the front of the front bracket 14.
The upper front frame 5a is attached to the upper part of the upper front frame so as to be freely rotatable about a pin, and can be fixed by inserting another pin.
The upper front frame 5a is suspended from the boom 2 by a hanging rope 11.

Reference numeral 6 denotes a frame hoisting winch that is attached to the front frame 5 and raises and lowers the front frame 5, and a hoisting rope 7 wound around the hoisting winch 6 is attached to the sheave 15a provided on the boom 2 and the upper front frame 5a. The front frame 5 is rotated between the front frame 5 and the sheave 15b, and the front frame 5 is undulated by the operation of the frame undulating winch 6.

The Kelly bar 8 has a rectangular cross section, and the Kelly bar drive device 3 is attached to the upper front frame 5a.
It is inserted into the square hole of the rotor 6 so that it can move up and down.

In addition, when using the auxiliary hoisting winch 3 as a crane during earth drilling work, as shown in FIG. Embrace the frame 5, attach the hook 12 to the tip of the auxiliary winding rope 10b hung around the sheaves 37 and 38, and attach the suspended load 13 to the hook 12.
hang it up and perform crane work. To make this possible, sheaves 37 and 3 are installed at the top of the boom 2.
Two or more winding ropes 8 are provided coaxially, and for example, a main winding rope 10a is hung around the right sheaves 37 and 38, and an auxiliary winding rope 10b is hung around the left sheaves 37 and 38.

Furthermore, if necessary, a bracket having a sheave (both not shown) may be attached to the top of the boom 2, and the auxiliary hoisting rope 10b wound around the auxiliary hoisting winch may be hung on the sheave to perform crane work. There is also.

Furthermore, this earth drill can be used as a crane by removing the front frame 5 together with the Kelly bar drive device 36 and the frame hoisting winch 6, and by hanging the main winding rope 10a between the sheave 38 and a hook block (not shown). can.

Further, during transportation, as shown in FIG. 10, the Kelly bar 8 is removed and the boom 2 is retracted for transportation. In this way, the earth drill takes various positions.

By the way, in the conventional earth drill, the front frame 5 is fixed to the lower part of the lattice boom with a pin, so even when the boom is raised and lowered, the relative angle between the boom and the front frame does not change.

However, in the case of the telescopic boom 2 shown in FIGS. 8 to 10, the boom width is narrow and the boom hoisting cylinder 4 is installed under the boom 2, so it is not possible to install the front frame 5 at the bottom of the boom 2. Can not. Therefore, the front frame 5 is attached to the front bucket 14.

In such a mounting structure for the front frame 5, since the mounting pins 34 of the boom 2 and the mounting pins 35 of the front frame 5 are in different positions, the angle of the boom 2 may be changed to mount the front frame 5.
When the boom 2 and the front frame 5 or the devices attached to them come into contact with each other, the parts that come into contact with each other change.

For example, as shown in Fig. 1, when the angle of the boom 2 is large, if the front frame 5 is hugged too much, the rod of the boom hoisting cylinder 4 will come into contact with the front frame hoisting winch 6 (the contact points are indicated by A). ) and, as shown in Figure 2, boom 2.
When the angle is approximately intermediate, the rod attachment portion of the boom hoisting cylinder 4 and the float frame hoisting winch 6 come into contact (indicated by B). In addition, in the state shown in FIG. 2, the line connecting the position of the mounting pin 35 of the front frame 5 and the sheaves 15a, 15b is close to a straight line, so the boom hoisting rope 7
The tension increases. Furthermore, if the boom 2 is raised from the state shown in FIG. 2, there is a risk that the frame hoisting rope 7 will break (because the hoisting force exerted by the boom hoisting cylinder 4 is greater than the strength of the frame hoisting rope 7).

Further, as shown in FIG. 3, when the angle of the boom 2 is small, if the front frame 5 is held in too much, the sheave 15a and the sheave 15b will come into contact as shown by arrow C.

Such contact between the boom 2 and the front frame 5 and excessive tension on the frame hoisting rope 7 will cause
This occurs when the frame hoisting winch 6 is accidentally wound too far, or when the boom 2 is raised when the boom 2 and the front frame 5 are close together.

(Problems to be Solved by the Invention) In view of the above-mentioned points, the present invention aims to prevent accidents caused by contact between the boom and the front frame and breakage of the frame hoisting rope due to excessive tension, regardless of the size of the angle of the boom. It is an object of the present invention to provide an earth drill frame undulation safety device which can prevent the occurrence of such occurrence and expand the range in which the boom and the front frame can be raised without paying attention to the above-mentioned contact.

(Means for Solving the Problems) In order to achieve this object, the present invention mounts the boom and the front frame so that they can rise and fall freely around different positions in the front and back of the main body, and the boom and the front frame are mounted on the back of the front frame. In an earth drill that is equipped with a front frame hoisting device that winds up and unwinds a rope that is passed between the sheaves of the front frame, and a boom hoisting cylinder is installed between the front frame and the boom, the boom or boom side equipment and the front frame are installed. Alternatively, either an approach detection switch that is activated when the front frame side equipment approaches and a striker that operates the approach detection switch are attached to the boom hoisting cylinder, and the other is attached to the front frame;
A circuit that shuts off a boom-raising side operation circuit of the control valve of the boom hoisting cylinder when the approach detection switch is activated, and a circuit that shuts off a front frame-raising side operation circuit of the front frame control valve when the approach detection switch is activated. The striker for actuating the approach detection switch is characterized in that the shape of the striker that operates the approach detection switch is formed into a curved shape with a substantially central portion in the vertical direction protruding toward the limit switch side.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. In this embodiment, as shown in FIGS. 1 to 3, a limit switch 1 is installed on the surface of the front frame 5 on the boom 2 side to detect the approach of the boom 2 or the boom hoisting cylinder 4.
7 is attached, and a striker 16 for operating a limit switch 17 is attached to the boom hoisting cylinder 4.

The striker 16 has a curved shape with its vertical center portion protruding toward the front frame 5, and is mounted as shown in FIG. 4. That is, the ring-shaped striker mounting fittings 16a, 16a are tightened and fixed to the tube of the boom hoisting cylinder 4 with bolts 40, 41, and the mounting plate 4 is fixed to each striker mounting fitting 16a, 16b.
Insert the bolts 16c and 16d attached to both ends of the striker 16 into the holes 2 and 43, and
Both ends of the striker 16 are mounted in a position-adjustable manner by two nuts 44 and 45 screwed onto the mounting plates c and 16d, respectively, so as to sandwich mounting plates 42 and 43 therebetween.

FIG. 5 shows a hydraulic circuit for raising and lowering the boom and raising and lowering the front frame of this embodiment. In FIG. 5, 18 is a hydraulic pump that supplies hydraulic oil to the boom hoisting cylinder 4, etc., and 19 is a boom hoisting cylinder 4.
control valve, each pressure receiving part 19a, 19
b is connected to a boom hoisting pilot valve (not shown) via pilot circuits 46 and 47, and a boom hoisting stop solenoid valve 21 is inserted into the boom hoisting pilot circuit 46. 20 is a counter balance valve that prevents the boom from running away when lowering it.

Further, 22 is a hydraulic pump that supplies hydraulic oil to the frame hoisting winch 6, etc.; 23 is an electromagnetically operated control valve for the frame hoisting winch 6;
4 is a counterbalance valve that prevents the winch 6 from running away during lowering, and 25 is a hydraulic motor that drives the winch 6.

FIG. 6 shows an electric circuit that controls the solenoid valve 21 and control valve 23 shown in FIG. relay, 2
8 and 29 are a normally closed contact and a normally closed contact of the relay 27, respectively, and the normally closed contact 28 is connected to the solenoid valve 2.
The normally closed contact 29 is connected to the solenoid 21a of the frame hoisting winch 6 and inserted between the power supplies, and the normally closed contact 29 is connected to the hoisting side solenoid 23a of the control valve 23 of the frame hoisting winch 6. switch 3
0 is connected to one fixed contact c. Also, the other solenoid 23b of the control valve 23
is connected to the other fixed contact a of the manual switch.

Next, the operation of this embodiment device will be explained. When the front frame 5 is away from the boom 2 or the boom hoisting cylinder 4, as shown in FIG. 6, the normally closed contact of the limit switch 17 is closed, so the relay 27 is energized; Contact 28 opens and solenoid 21
Since point a is not energized, solenoid valve 21 is maintained at position B in FIG. Therefore, when the operator operates the boom hoisting pilot valve,
When pilot pressure oil is supplied to the pressure receiving part 19a of the control valve 19 via the pilot circuit 46, the control valve 19 is switched to the B position,
The boom hoisting cylinder 4 extends and the boom 2 moves in the upward direction. Further, when the boom hoisting pilot valve is operated in the lowering direction, pilot pressure oil is supplied to the pressure receiving part 19b via the pilot circuit 47, the control valve 19 is switched to the A position, and the boom 2 is lowered.

In addition, in FIG. 6, the limit switch 17
When the solenoid 23a is not operating, the normally closed contact 29 is closed, so when the operator operates the manual switch 30 to connect the movable contact b to the fixed contact c side, the solenoid 23a is connected to the normally open contact 29. Energized and energized, the control valve 23 is switched to position B, and the frame hoisting winch 6 is moved in the hoisting direction. Conversely, when the manual switch 30 is operated to connect the movable contact b to the fixed contact a side, the solenoid 23b is energized and the control valve 23 is
The frame hoisting winch 6 is moved in the lowering direction of the front frame 5.

Next, as shown in FIGS. 1 to 3, the frame hoisting winch 6 is overwound, causing the winch 6 to
approaches the boom hoisting cylinder 4, or the sheave 1
When 5a and 15b approach, limit switch 1
7, the operating rod 17a contacts the striker 16 and switches, and as shown in FIG. 6, the normally closed contact of the limit switch 17 opens, so the relay 27 is demagnetized, and as a result, the normally open contact 29 opens, so that the solenoid 23a is Since the energization is stopped and the control valve 23 is in the neutral position, the hydraulic motor 25 is stopped and the hoisting of the front frame 5 by the frame hoisting winch 6 is automatically stopped. In other words, the frame hoisting winch 6 cannot be operated in the hoisting direction, and can only be hoisted down.

In addition, due to the operation of the limit switch 17, the normally closed contact 28 is closed and the solenoid 21a is energized, so that the solenoid valve 21 is switched to the A position in FIG. Therefore, the pressure receiving part 19a of the control valve 19 communicates with the oil tank 26 and is in a neutral position, so that the raising operation of the boom 2 is prohibited. Therefore, when the front frame 5 approaches the boom 2 or the boom hoisting cylinder 4 and the striker 16 pushes the operating rod 17a of the limit switch 17, it becomes impossible to raise the boom 2, and the hoisting by the frame hoisting winch 6 becomes impossible. Since the operation is stopped and becomes impossible, an accident of contact between the boom 2 or the boom hoisting cylinder 4 and the front frame 5 can be prevented.

Further, in this embodiment, since the striker 16 is formed in an arc shape, when the angle of the boom 2 is large as shown in FIG.
The operating rod 17a of No. 7 hits the lower side of the striker 16, and when the angle of the boom 2 is in the middle as shown in FIG. When the angle of the striker 1 is small, the operating rod 17a
6, and at each boom angle, before the boom 2 or the boom hoisting cylinder 4 and the front frame 5 (including equipment on the front frame 5) come into contact or the tension on the frame hoisting rope 7 becomes excessive. Raising the boom and hoisting the front frame 5 can be stopped.

In the above embodiment, the winch 6 was used as the frame raising and lowering device, but as shown in FIG. 7, a hydraulic cylinder 31 may also be used. In addition, the seventh
In the figure, 32a is a fixed sheave attached to the front frame 5, 32b is a movable sheave attached to the rod of the cylinder 31, and the frame hoisting rope 7 is wound around these and the sheaves 15a and 15b.

Further, when the present invention is implemented, an alarm device such as a buzzer may issue an alarm when the limit switch 17 is activated. This alarm device is
This is realized by connecting and inserting a buzzer or the like in series with the normally closed contact 28 shown in FIG.

Furthermore, in the above embodiment, the striker 16 was attached to the boom 2 side (boom cylinder 4), and the limit switch 17 was attached to the front frame 5.
The limit switch 17 may be attached to the boom 2 side, and the striker 16 may be attached to the front frame 5 side. Further, although the striker in the above embodiment has an arc shape, it is conceivable that the striker may have a curved shape other than an arc shape depending on the positional relationship between the boom attachment pin and the front frame attachment pin and the arrangement of each device on the front frame. Further, in the present invention, as the switch for detecting approach, a switch that detects approach magnetically, electromagnetically, or optically can also be used.

Further, the present invention is applicable not only to the case where the boom 2 is telescopic, but also to other earth drills in which the positions of the mounting pins of the boom 2 and the front frame 5 are different.

(Effects of the Invention) As described above, the present invention includes an approach detection switch that is activated when the boom or boom cylinder approaches the front frame, and an approach detection switch that detects the approach direction between the boom and the front frame by the operation of the approach detection switch. Since it is equipped with an automatic stop device that stops the operation, it is possible to prevent accidental contact between the boom and the front frame, or equipment attached to both, due to excessive hoisting of the front frame or excessive lifting of the boom. In addition, the striker that activates the approach detection switch is formed in a curved shape with its vertical center protruding toward the other side due to the arrangement of the front frame hoisting devices and other equipment on the front frame, so the boom angle It is possible to prevent contact between the boom and the front frame or their mounted equipment regardless of the situation, and by forming the strarica into a curved surface, at each boom angle, within the range where such contact does not occur, the boom and front frame can be raised. can be carried out almost to the limit, and the range in which the boom and front frame can be raised can be expanded without having to be careful about the above-mentioned contact.

Further, generation of excessive tension in the frame hoisting rope is prevented, and breakage of the front frame hoisting rope due to boom raising operation or overwinding of the front frame can be prevented.

Furthermore, since the above-mentioned accidents can be prevented, the burden on the operator can be reduced and work efficiency can be improved.

[Brief explanation of the drawing]

Figures 1 to 3 are side views showing an embodiment of the earth drill front undulating safety device according to the present invention for cases where the boom angle is large, intermediate, and small, respectively, and Figure 4 is a side view of the embodiment. A side view showing the striker, FIG. 5 is a hydraulic circuit diagram for boom hoisting and front frame hoisting in this embodiment, and FIG.
The figure is an electrical circuit diagram for hydraulic circuit control in Figure 5, and Figure 7.
Figure 8 is a side view showing another embodiment of the present invention; Figure 8 is a side view showing a conventional earth drill in a digging position; Figure 9 is a side view showing the conventional earth drill in a crane working position with an auxiliary winch; FIG. 10 is a side view similarly showing the transportation attitude.

Claims (1)

[Claims] 1 The boom and front frame are installed so that they can be raised and lowered at different positions on the front and rear of the main body, and a front frame undulation device is installed on the back of the front frame to wind up and unwind the rope that is passed between the boom and the sheave of the front frame. , an earth drill in which a boom hoisting cylinder is installed between a front frame and a boom, and an approach detection switch that is activated when the boom or boom side equipment approaches the front frame or front frame side equipment; one of the strikers to be activated is attached to the boom hoisting cylinder and the other is attached to the front frame, and a circuit for cutting off a boom-raising side operating circuit of a control valve of the boom hoisting cylinder by actuation of the approach detection switch; and a circuit for cutting off a front frame raising side operation circuit of the control valve of the front frame when the approach detection switch is operated, and a striker for operating the approach detection switch has a shape such that approximately the center in the vertical direction protrudes toward the limit switch side. An earth drill front undulation safety device characterized by a curved shape.