JPH0552371B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is capable of clamping and fixing the above-ground exposed portion of an existing pile row buried underground using first and second clamps for various types of work or self-propelled movement. This is a clamp safety device applied to working equipment on piles, which securely clamps the pile to at least one clamp while it is clamped and fixed on the existing pile, and prevents the equipment from opening simultaneously due to malfunction of both clamps. This invention relates to a clamp safety device for preventing accidents such as falling over.

(Prior technology) A typical example of a reaction force-type work device on a pile is a self-propelled type that moves along the pile row to perform various works while clamping and fixing the exposed above-ground part of the existing pile row buried underground. There is a type pile press-in/extraction machine. A device of this type has two clamps for pilings that are movable relative to each other.

For example, in the above-mentioned self-propelled pile press-in/extraction machine,
A first clamp consisting of a plurality of clamps is provided under a base that is movable or rotatable in the front, rear, left and right directions, and a second clamp is provided as a stake chuck on an elevating head that can slide up and down with respect to the base. ing. When moving on a pile, one clamp is held on the pile, the other clamp is opened, and the opened clamp is moved to grip another pile. By repeating this operation for alternate clamps, the device moves on the pile row.

(Problems to be Solved by the Invention) The movement of the above device on the row of piles is controlled manually because it needs to be operated appropriately depending on the pitch of the piles and the situation. Particular care must be taken when opening and closing the clamps that support the heavy equipment.
If both clamps are opened at the same time, the device will tip over. Although such accidents rarely occur due to operator error, there is always a possibility that such an accident may occur.

That is, there are cases where the pile is actually clamped with the clamp, but the pile is not clamped, or the pile is not clamped, or the clamp may be mistakenly removed from the supporting state. Although it is possible to recognize the closed state of the clamp by a change in the hydraulic pressure supplied to the clamp, it is impossible to distinguish between the pile clamping state and the air clamping state.

Alternatively, a control system using a hydraulic sensor or an electric sensor may be applied, but the structure becomes complicated. Complex circuits not only increase the cost of the control system, but also increase the probability of failure and make it impossible to ensure sufficient safety.

Therefore, it is an object of the present invention that only when both the first and second clamps installed on various working devices such as a self-propelled pile press-in/extraction machine are clamping a pile, one of the clamps can be attached to a pile. If only one clamp is clamping a pile and the other is in a non-clamping state or an air clamping state, the clamp that is clamping the pile will not be allowed to release the pile, to prevent both clamps from opening due to malfunction. It has a simple structure that does not cause accidents such as equipment falling during operation, and allows for automatic safety management.
Our goal is to provide a reliable clamp safety device.

(Means for Solving the Problems) In order to achieve the above object, the clamp safety devices according to the present invention are provided such that each of the clamp safety devices can be clamped to the exposed above-ground portion of an existing pile, and one is displaceably movable relative to the other. In the first and second clamp safety devices, each of the first clamp and the second clamp includes a piston, a cylinder that defines a front chamber and a rear chamber by the piston, and a cylinder that defines a front chamber and a rear chamber by the piston. A front chamber liquid path and a rear chamber liquid path that communicate with each other, and an escape liquid path that opens into the rear chamber when the piston reaches the front dead center and opens into the front chamber when the piston moves rearward are connected to the front chamber. A pressure detection means is provided to communicate with the chamber liquid path, and detects the liquid pressure supplied to the rear chambers of both the first and second clamps,
If the control device determines that the hydraulic pressure in one rear clamp chamber is in a high pressure state, the control device controls the switching valve to maintain the high pressure state;
If it is determined that the hydraulic pressure in both of the clamp rear chambers is high pressure, the switching valve is controlled to reduce the hydraulic pressure in one of the clamp rear chambers, making it possible to release the pile from the clamp. It is characterized by

(Function) By having the first and second clamps accept the above-ground exposed part of the existing pile buried above the ground and supplying hydraulic pressure to the rear chamber of the cylinder, the piston is pushed forward, and this action Hold the stake. Fixation of the working device on the pile can be achieved by means of at least one clamp.

The hydraulic pressure supplied to the cylinder rear chamber of each clamp is constantly detected and changes in pressure are monitored. When the clamp is holding the pile, the rear chamber of the cylinder is open only to the rear chamber liquid path, and the high liquid pressure introduced therefrom is maintained. When the piston is located at the front dead center, it is in an air-held state in which the clamp does not receive the pile, and at this time, the escape liquid passage provided in the cylinder opens into the rear chamber of the cylinder. As a result, the hydraulic pressure supplied to the rear chamber of the cylinder escapes to the front chamber liquid passage through the escape liquid passage, so that the supplied hydraulic pressure is relatively reduced. Further, when the supply liquid pressure shows the lowest pressure, the clamp is in a non-clamping state. Therefore, by identifying the three-stage change in the hydraulic pressure supplied to the rear chamber of the cylinder, the clamp can be used to determine whether the clamp is in a pile-pinch state, an air-pinch state, or
The non-clamping state can be accurately and automatically determined.

Therefore, since one of the clamps is set to be openable only when both clamps are in the pile clamping state, at least one clamp is always in the pile clamping state. This makes it possible to avoid unsupporting the device due to the opening of both clamps.

(Embodiment) FIG. 1 is an overall view showing a schematic configuration of an embodiment of a clamp safety device according to the present invention. In the illustrated embodiment, the clamp safety device of the present invention is applied to a pile press-in/extraction machine for construction, but the applicable device is not limited to this. That is, the clamp safety device of the present invention can be applied to various working devices having two clamps, each of which is movable and displaceable on a pile row, as will be described later.

A pile press-in/extraction machine 1, which is a device for working on piles, has a first clamp 2 and a second clamp 3. A plurality of first clamps 2 are provided at the bottom of a base 4 that can be moved back and forth and left and right, and a second clamp 3 is built into an elevating head 5 that can be driven up and down in the front part of the base 4. . Therefore, as shown in Figure 1,
When the first clamp 2 is clamped to the exposed part of the pile P on the ground and holds the whole pile press-in/extraction machine fixed, the second clamp 3 is moved to the first clamp by driving the base 4 to the lifting head 5 respectively. It can be moved up, down, left, right, front and back with respect to 2. By repeating alternately holding the piles and moving the clamps back and forth, the entire device can be moved by itself along the row of piles.

As shown in FIG. 2, the first and second clamps 2 and 3 each contain a piston 11 having a piston rod 10 and the piston 11, and the pistons define an internal space between a front chamber 12 and a rear chamber 13. The cylinder 14 is divided into two parts. The piston rod 10 protrudes outside the cylinder 14, has a movable tooth member 15 at its tip, and is arranged so as to be movable relative to the fixed tooth member 17 with the pile receiving space 16 in between.

The cylinder 14 is provided with a front chamber liquid path 18 that is always open to the front chamber 12 and a rear chamber liquid path 19 that is always open to the rear chamber 13.

Reference numeral 20 denotes an escape liquid path branched from the front chamber liquid path 18. This escape liquid passage 20 is connected to the cylinder rear chamber 13 when the piston 11 is located at the frontmost position (front dead center).
It is provided in a position that opens into the cylinder front chamber 12 at least when the piston 11 is located at the rear. Further, the opening diameter of the escape liquid passage 20 is smaller than that of the front chamber liquid passage 18. As an example, when the opening diameter of the front chamber liquid path 18 is 6 mm, the escape liquid path 20
The thickness should be about 1mm.

With the above-mentioned clamp configuration, in order to press the piston rod 10 to the piston 11 forward, oil pressure or hydraulic pressure is introduced from the rear chamber liquid path 19 into the cylinder rear chamber 13 to move the piston 11 forward. As shown in FIG. 3A, the pile P interposed in the pile receiving space 16 is connected to the movable tooth member 15 and the fixed tooth member 17.
It can be held between. In this pile clamping state, the hydraulic pressure supplied to the cylinder rear chamber 13 is maintained and reaches its maximum level.

However, when the piston 11 is in an air-paired state where no pile is present in the pile receiving space 16, the piston 11 moves to the front dead center as shown in FIG. By this,
In this air-held state, the hydraulic pressure supplied to the rear chamber 13 is relatively low. Piston 11 from air-paired state
When returning to the rear, fluid pressure is introduced into the front chamber 12 through the front chamber fluid path 18, but at this time, the escape fluid path 2
0 also opens into the rear chamber 13. However, since the escape liquid passage 20 has a smaller opening diameter than the front chamber liquid passage 18, the amount of hydraulic pressure flowing into the front chamber 12 from the front chamber liquid passage 18 is greater than the amount of liquid pressure flowing into the rear chamber 13 through the escape liquid passage 20. Since there are more pistons, the piston 11 is returned to the rear.
When the piston 11 retreats and closes the escape liquid path 20, the return speed of the piston increases somewhat.

As shown in FIG. 1, the hydraulic system for driving and controlling each of the first and second clamps 2 and 3 having the above-mentioned configuration includes a liquid supply pipe 2 from a hydraulic pressure source 21 such as a hydraulic pump.
2 and 23 are connected to each clamp 2 and 3 via pipe lines 26, 27, 28, and 29 which are selectively branched by switching valves 24 and 25.

By switching the switching valve 24, the liquid pressure from the liquid supply pipe 22 is sent to either the pipe line 26 or 27, and the cylinder front chamber 12 or the rear chamber 1 of the first clamp 2 is fed.
3. Since the hydraulic pressure introduced into one of the cylinder front chamber 12 and rear chamber 13 pushes the piston 11 forward, the hydraulic pressure that was filled in the other front chamber or rear chamber is transferred to the other pipe line 26 to 27. It is discharged into a drain tank 31 via a valve 24 and a drain pipe 30.

Similarly, by switching the switching valve 25, the hydraulic pressure source 2
The hydraulic pressure from 1 is sent to one of the pipes 28 and 29 to the cylinder front chamber 12 and rear chamber 13 of the second clamp 3.
from the other front chamber to the rear chamber through the other pipe lines 28 and 29, and further through the switching valve 25 and the drain pipe 32 to the drain tank 3.
It is discharged at 3.

A pressure detector 3 is installed in the middle of the pipe lines 26 and 28 connected to the cylinder rear chambers 13 and 13 of both clamps 2 and 3.
4 and 35 are provided, and a controller 36 monitors the pressure values detected by the pressure detectors 34 and 35.

This controller 36 normally controls the pile press-in and pull-out machine 1.
The driver can control and drive each drive part of the 1st and 2nd clamps, and can manually command the movement or rotation of the base 4 back and forth and left and right, and the lifting and lowering of the lifting head 5. It has such functions. Here, the switching drive control and lock control of the switching valves 24 and 25 are performed electrically or hydraulically mechanically, so this control system is schematically shown in the drawings.

The controller 36 has a function that allows only one of the switching valves 24 and 25 to be unlocked only when both pressures detected by the pressure detectors 34 and 35 show a high level. In normal operating conditions, if either pressure detector 34 or 35 indicates a low to medium level of fluid pressure,
The switching valve of the clamp exhibiting a high level is not activated. That is, as described above, when the hydraulic pressure in the rear chamber 13 of the cylinder of the clamp reaches a high pressure state, the clamp is in the pile clamping state.
Therefore, if the cylinder rear chamber pressures of both clamps 2 and 3 are at a high level at the same time, the supporting force of the device can be ensured even if one of the clamps is removed. When both clamps are in this state of holding the pile, the controller 36 can optionally unlock one of the clamps.

When the pressure in the cylinder rear chamber 13 of either clamp is at a low or medium level, the clamp is in a non-clamping state or in an air-pinch state as described above, ensuring the supporting force of the device. The controller 36 maintains the locked state of the clamp in order to maintain the pressure in the cylinder rear chamber of the clamp.

When operating a pile press-in/extraction machine equipped with the clamp safety device configured as described above, the operator removes one clamp from the pile, moves it forward or backward, clamps the pile again, and then removes the other clamp from the pile. By repeating the procedure of removing the clamp, moving it to follow the previous clamp, and clamping the pile again, the device can be moved by itself along the pile row. In this case, even if the driver misidentifies that the pile is clamped, or removes both clamps by mistake, the controller acts to maintain the locked state of at least one clamp clamping the pile. Driver operations are disabled. Therefore, it is advisable to fix the switching lever of the device or provide an auxiliary device to issue an alarm in the event of such an erroneous operation.

(Effects of the Invention) As explained above, according to the present invention, the cylinder is divided into the front chamber and the rear chamber by the piston, and the front chamber liquid path opens to the front chamber and the rear chamber liquid path opens to the rear chamber. In addition to the fluid passage, an escape fluid passage that opens into the rear chamber when the piston is located at a front dead center and opens into the front chamber when the piston moves rearward is provided in the cylinder and communicates with the front chamber fluid passage. first and second clamps,
The hydraulic pressure supplied to the rear chambers of the cylinders of both clamps is monitored, and when the hydraulic pressure in the rear chambers of both cylinders exhibits a high level, it is determined that both clamps are in the pile clamping state, and one of the clamps is Since only the pile can be released, it is possible to automatically prevent both clamps from opening at the same time due to a driver's erroneous operation, thereby preventing accidents such as the device falling over and ensuring safety.

In addition, it is possible to accurately identify the pile clamping state, non-clamping state, and air clamping state by changing the hydraulic pressure in the rear chamber of the cylinder of the clamp. However, in the air clamping state, the pressure of the piston presses into the cylinder's escape fluid path. It does not put a load on the hydraulic system because it escapes through the

The clamp structure, which allows the clamping state to be determined based on changes in supply fluid pressure, has a simple structure with few moving parts, which reduces failure rates and is easy to apply to various machine tools. can be done.

Furthermore, since it can be applied to the control system without major improvements, it can be used in various existing machines.

[Brief explanation of drawings]

The drawings show an embodiment of the clamp safety device according to the present invention, in which Fig. 1 is a schematic explanatory view of the whole, Fig. 2 is a side sectional view showing the schematic structure of the clamp, and Fig. 3 A and B show the operation of the same clamp. It is a principle explanatory diagram. 1... Working device, 2... First clamp, 3...
Second clamp, 11... Piston, 12... Front chamber, 13... Rear chamber, 14... Cylinder, 18...
Front chamber liquid path, 19... rear chamber liquid path, 20... escape liquid path.

Claims (1)

[Claims] 1. A clamp safety device for a working device on an existing pile having a first clamp and a second clamp movable with respect to the first clamp, each of the first clamp and the second clamp teeth,
A piston, a cylinder that defines a front chamber and a rear chamber by the piston, a front chamber liquid path and a rear chamber liquid path that communicate with the front chamber and the rear chamber, respectively, and when the piston reaches a front dead center. An escape liquid path that opens into the rear chamber when the piston moves rearward and opens into the front chamber when the piston moves rearward is provided in communication with the front chamber liquid path, and supplies the liquid to the rear chambers of both the first and second clamps. When the hydraulic pressure is detected by the pressure detection means and the control device determines that the hydraulic pressure in one of the rear clamp chambers is in a high pressure state, the control device controls the switching valve to maintain the high pressure state. If it was determined that the hydraulic pressure in both of the clamp rear chambers was high pressure, the switching valve was controlled to reduce the hydraulic pressure in either of the clamp rear chambers, making it possible to release the pile from the clamp. A clamp safety device for a working device on an existing pile, characterized by: