JPS6329051B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulically operated drop hammer for driving piles.

Diesel hammers, which have been widely used in the past, are extremely noisy, so hydraulic drop hammers are now being used. A hydraulic drop hammer uses a hydraulic cylinder to raise a hammer ram, and releases the hydraulic pressure in the hydraulic cylinder to cause the hammer ram to fall under its own weight.
30215 is proposed.
This product has a hydraulic cylinder attached to the outside of the casing, and a hammer ram housed inside the casing that can move up and down, suspended via a wire and a movable pulley and a fixed pulley, and the expansion and contraction stroke of the hydraulic cylinder is small. Nevertheless, it has the advantage of increasing the falling stroke of the hammer ram.

However, as described above, when the hammer ram is hoisted via a wire, the wire is subject to significant wear and tear, and maintenance of the wire, movable pulley, and fixed pulley is troublesome. In addition, since the above-mentioned wire is restricted by the suspended load of the wire, the weight of the hammer ram must be reduced. In other words, it is necessary to obtain a predetermined impact energy by increasing the falling stroke. In order to ensure the falling height of the hammer ram, the height of the casing needs to be large, which has the disadvantage of making it long.

Additionally, if the falling height is high, it takes a certain amount of time for the hammer ram to hit the impacting body after the hydraulic pressure in the hydraulic cylinder is released, which limits the ability to set short time intervals for pile driving. However, there are problems such as restrictions on improving work efficiency.

The present invention was made based on the above circumstances, and its purpose is to increase the weight of the hammer ram without using wires, and to shorten the falling height of the hammer ram. We would like to provide a hydraulic drop hammer for pile driving that can obtain a predetermined impact energy, thereby making it possible to shorten the casing, as well as shortening the time interval between pile driving and improving the efficiency of pile driving work. That is.

That is, in the present invention, a hydraulic cylinder is fixed to the upper end of a casing housing a hammer ram so as to be movable up and down, and the hammer ram is directly connected to the piston rod of this hydraulic cylinder, eliminating wires and pulleys. The hammer ram is characterized in that when the ram falls, the hydraulic oil in the piston ascending chamber is quickly released toward the piston descending chamber to encourage the hammer ram to fall under its own weight.

An embodiment of the present invention will be described below based on the drawings.

In the figure, 1 is a cylindrical casing, and a sliding arm 2 is provided protruding from the outer surface. The sliding arm 2 is slidably guided by a leader X installed on the ground. A striking body 4 is provided at the lower end of the casing 1 so as to be movable up and down by a predetermined stroke. The striking body 4 includes a medium enclosure chamber 6 formed by abutting upper and lower members 6a and 5b, and this enclosure chamber 6 is filled with a pressure accumulation medium Y such as petroleum-based hydraulic oil. It is formed by fitting the lower part of an anvil 7 that can move up and down. A hardwood piece 8 for sound reduction is attached to the upper end of the anvil 7. When the hardwood 8 is struck, the anvil 7 is pushed and compresses the pressure storage medium Y, and the impacting body 4 is pushed by the compressive energy stored in the pressure storage medium Y. A cap-shaped holder 9 is connected to the lower end of the striking body 4, and the head of the stake Z is fitted into this holder 9 and held therein. Note that the cap-shaped boulder 9 may be replaced with a chuck. Upper member 5a of anvil 7
Flanges 10a and 10b are formed on the
A stopper 11 as shown in FIG. 2 is provided on the side wall of the casing 1 between the flanges 10a and 10b. The striking body 4 can move up and down within the range where the stops 11 come into contact with the flanges 10a, 10b.

12 is a hammer ram, which is housed in the casing 1 so as to be vertically movable. This hammer ram 12 is larger and heavier than the conventional wire-suspended type.

A hydraulic cylinder 15 is connected to the end plate 13 that closes the upper end of the casing 1 via a block bracket 14.
is hanging. The hydraulic cylinder 15 is arranged on the axis inside the casing 1, and a piston rod 17 connected to a piston 16 is suspended therefrom. The lower end of the piston rod 17 is connected to the hammer ram 12.
is connected to. At this time, a recessed hole 18 is formed in the center of the hammer ram 12, and this recessed hole 18 has a size that allows the hydraulic cylinder 15 to be accommodated in a movable manner. is connected to the bottom of the cylinder 15
When the hammer ram 12 is pulled up by the operation of is made smaller.

A piston ascending chamber 20 and a piston descending chamber 21 divided by the piston 16 of the hydraulic cylinder 15 communicate with an ascending passage 22 and a descending passage 23 shown in FIG. 3, respectively. These passages 22 and 23 are connected to a switching valve 26 via hoses 24 and 25, respectively. The switching valve 26 is connected to a hydraulic pump 27 and an oil tank 28, and the switching valve 26, the hydraulic pump 27, and the oil tank 28 are installed, for example, on the side of a vehicle body such as a crawler crane. Therefore, the passage 22,2
3 and the switching valve 26 is a flexible hose 2.
4 and 25.

The passages 22 and 23 are connected by a relief passage 29 at a position as close as possible to the hydraulic cylinder 15. An electromagnetic one-way valve 30 is attached to the relief passage 29 to open and close the relief passage 29. In this embodiment, the electromagnetic one-way valve 30 is formed by a main pilot check valve 31, an auxiliary pilot check valve 32, and an electromagnetic shut-off valve 33. The main pilot check valve 31 is located in the ascending passage 2.
The pressure of the introduction hole 34 communicating with the valve body 35 is applied to one side of the valve body 35, and the pilot pressure of the spring 36 pressing the valve body 35 and the pilot passage 37 is applied to the opposite side of the valve body 35. When the pressure on the introduction hole 34 side is overcome, the introduction hole 34
is communicated with the escape passage 29. Pilot passage 3
7 is communicated with the rising side passage 22 via the throttle 38. Further, the pilot passage 37 is connected to press one side of the valve body 39 of the auxiliary pilot check valve 32, and the pilot pressure guided from the spring 40 and the pilot introduction passage 41 acts on the opposite side of the valve body 39. I'm starting to do that. The pressure balance acting on the valve body 39 is disrupted and the valve body 39
When is pressed, the spill passage 42 is opened and the pilot passage 37 is communicated with the spill passage 42. The spill passage 42 is connected to the relief passage 29. The pilot introduction passage 41 of the valve body 39 is selectively switched into a high pressure side pilot passage 43 and a low pressure side pilot passage 44 by the electromagnetic on-off valve 33.
The high pressure side pilot passage 43 communicates with the rising side passage 22 and the low pressure side pilot passage 44.
is in communication with the descending passage 23.

The electromagnetic on-off valve 33 is attached to an end plate 13 that closes the upper end of the casing 1, as shown in FIG.
1 and an auxiliary pilot check valve 32 are mounted within the block bracket 14. In FIG. 4, the same numbers as in FIG. 3 indicate the same components. In addition, 45 and 46 in FIG. 4 indicate bushes. The main pilot type check valve 31 and the auxiliary pilot type check valve 32 shown in FIG.
is suitable.

In this embodiment, the electromagnetic on-off valve 33 is controlled by an electronic controller 50 such as a microcomputer. That is, 51 shown in FIG. 3 is a magnetic sensor, which generates a pulse signal etc. when a magnet 52 attached to the hammer ram or piston rod 17 passes. This pulse signal is transmitted to the controller 50. controller 50
is based on the set value given from the controller 53,
The electromagnetic switch 33 is operated after a predetermined time after the pulse signal is input. By adjusting the time from when a pulse signal is input to when the electromagnetic switch 33 is activated using the operating device 53, the time interval for piling can be changed.

Further, reference numeral 55 in FIG. 3 is an accumulator, which stores pressure when the piston 16 goes up, and applies the stored pressure to the piston 16 when the piston 16 goes down.

An embodiment of the above configuration operates as follows. That is, when the hammer ram 12 is at the bottom dead center, the electromagnetic on-off valve 33 connects the high pressure side pilot passage 43 to the pilot introduction passage 41 as shown in FIG. Then, the switching valve 26 is operated to forcefully feed hydraulic oil from the hydraulic pump 27 to the ascending passage 22, and at this time, the descending passage 23 is opened to the tank 28 side.

The hydraulic oil supplied to the rising side passage 22 is sent to the piston rising chamber 20 of the cylinder 15, so that the piston 16 is raised, and thus the hammer ram 12 is lifted up via the piston rod 17. Hammer ram 12 is raised away from hardwood 8.
Furthermore, when the piston 16 is raised, high-pressure hydraulic oil is applied to the piston raising chamber 20 against the weight of the hammer ram 12.
High pressure is also transmitted to 4. However, since high pressure is also applied to the high pressure side pilot passage 43, high pressure acts on the upper surface of the valve body 39 of the auxiliary pilot type check valve 32 through the pilot introduction passage 41, and therefore the pilot passage 37 and Spill passage 42 is not conductive. Pilot passage 3
Since high pressure is also acting on 7, the valve body 35 of the main pilot type check valve 31 is also pushed downward.
Therefore, the introduction hole 34 is closed and is not communicated with the escape passage 29.

Further, since the hydraulic oil in the piston descending chamber 21 of the hydraulic cylinder 15 is compressed by the rise of the piston 16, a part of it is stored in the accumulator 55 and passes through the descending passage 23 and is passed through the hose 25 to the tank 28. is released.

Magnet 5 of piston rod 17 shown in FIG.
2 passes the magnetic sensor 51 and rises, the controller 50 issues an operation command to the electromagnetic on-off valve 33 after a predetermined period of time based on the pulse signal from the magnetic sensor 51. That is, when the hammer ram 12 is raised to a predetermined height, the electromagnetic on-off valve 33 is switched. This switching connects the low-pressure side pilot passage 44 to the pilot introduction passage 41, so that the upper surface side of the valve body 39 of the auxiliary pilot type check valve 32 is opened to the low-pressure descending side passage 23. However, since high pressure is applied to the lower surface of the valve body 39 by the pilot passage 37, the valve body 39 is pushed up. Therefore, the pilot passage 37 is connected to the spill passage 42.

When the pilot passage 37 is communicated with the spill passage 42, the high pressure in the pilot passage 37 is released, so that the pressure acting on the upper surface of the valve body 35 of the main pilot type check valve 31 is reduced. Therefore, the valve body 3
5 is moved upward, and the introduction hole 34 is communicated with the escape passage 29. As a result, the rising side passage 22 becomes the relief passage 29.
It communicates with the descending side passage 23 through the piston rising chamber 20, thereby releasing the pressure in the piston rising chamber 20.

As a result, the hammer ram 12, piston rod 17, and piston 16 fall together due to their own weight. When the hammer ram 12 falls, the hammer ram 12 presses against the hardwood 8 and releases the pressure accumulation medium Y in the containment chamber 6 via the unpillar 7.
Compress. The accumulating pressure medium Y pushes down the impacting body 4 in an attempt to release compressive energy, so it hits the pile Z.

During the fall of the hammer ram 12,
The hydraulic oil in the piston ascending chamber 20 is flowed to the piston descending chamber 21 side via the relief passage 29. In addition, the volume of the inside of the piston lowering chamber 21 is larger than that of the piston raising chamber 20 due to the absence of the piston rod 17, so that the hydraulic oil from the relief passage 29 can be quickly sucked in due to the expansion of the volume. By continuing to supply hydraulic oil from the pump 27, the amount of hydraulic oil that is insufficient to flow from the piston ascending chamber 20 side is transferred from the hose 22 to the piston descending chamber 21 via the relief passage 29. replenish.

Therefore, the hydraulic oil in the piston ascending chamber 20 escapes smoothly, and the piston descending chamber 21 is quickly filled with hydraulic oil, so that the downward movement of the piston, that is, the fall of the hammer ram 12 by its own weight, is not hindered. In this case, the excess amount of hydraulic oil supplied to the piston descending chamber 21 is returned to the tank 28 via the hose 25.

In addition, at the beginning of the fall, the accumulator 5
The pressure stored in the piston 5 acts on the piston 16 to forcibly accelerate the initial speed, and this acceleration increases the falling speed of the hammer ram 12, thereby increasing the impact energy.

The magnet 52 of the piston rod 17 is the magnetic sensor 5.
When the electromagnetic on-off valve 33 is switched after a predetermined period of time after passing 1, that is, after the end of the fall, the auxiliary pilot type check valve 32 closes the spill passage 42, and accordingly, the pilot type check valve 33 closes the spill passage 29.
, the hammer ram 12 is raised again.

In the drop hammer of this embodiment, the hammer ram 12 is directly connected to the piston rod 17 of the hydraulic cylinder 15, so there is no need to pay attention to cutting the wire as in the conventional case, and there is no risk of wire breakage, so it can be used for a long time. It becomes the lifespan. Furthermore, since there is no restriction on the suspended load of the wire, the weight of the hammer ram 12 can be increased, and the loads of the piston 16 and piston rod 17 in addition to the large hammer ram 12 can be utilized as falling energy. When the impact energy is the same value, the larger the weight, the smaller the falling height, and therefore the vertical length of the casing 1 can be made smaller. In this embodiment, the hammer ram 12
Since the hydraulic cylinder 15 is accommodated in the recessed hole 18 when the hydraulic cylinder 15 is raised, the vertical dimension of the casing 1 can be further reduced by the length of the hydraulic cylinder 15, and conversely, the fall of the hammer ram 12 can be further reduced by the length of the hydraulic cylinder 15. The height can be increased.

By making the falling height of the hammer ram 12 relatively small, the time required for raising and dropping the hammer ram 12 is shortened, and from this, the time interval between pile driving can be shortened. Therefore, it is possible to increase the number of pile driving per unit time and improve work efficiency.

On the other hand, when the hammer ram 12 falls, the hydraulic oil in the piston ascending chamber 20 is supplied to the piston descending chamber 21 side through the escape passage 29, so that the piston 16 does not act as resistance to its own weight falling.
In particular, since the relief passage 29 is formed in the block bracket 14 disposed close to the hydraulic cylinder 15, the path conducted from the piston rising chamber 20 to the piston descent chamber 21 via the relief passage 29 is shortened. The pipe resistance is also reduced, and the piston descending chamber 21 is filled with good efficiency. The above path is shortened because of the pilot check valves 31 and 32.
This is also due to the fact that it is incorporated into the block bracket 14 located close to the cylinder 15.

Adopting the structure shown in FIG. 4 as the check valves 31 and 32, that is, logic valves, has the advantage of good responsiveness to pressure and the ability to quickly open and close the relief passage 29.

Moreover, as described above, when the hammer ram 12 falls, the hydraulic oil in the piston rising chamber 20 is quickly released to the piston descending chamber 21, so the hydraulic oil in the piston rising chamber 20 is released to the hose 24. At the same time, it is no longer necessary to supply a large amount of oil from the hose 25 to the piston descending chamber 21. Therefore, the hoses 24 and 25 provided to connect the switching valve 26 on the ground side and the hammer can be made small in diameter, and the diameter of the hoses 24 and 25 connected to the ground side switching valve 26 and the hammer can be reduced. It has the advantage of being easy to handle.

In addition, the block bracket 14 housing the check valves 31 and 32 is disassembled into 14a and 14 as shown in FIG.
b, 14c, maintenance of the check valves 31, 32 becomes easy.

Note that the present invention is not limited to the above embodiment, and in particular, the main pilot check valve 31 and the auxiliary pilot check valve 32 as the electromagnetic one-way valve 30 are not limited to those of the embodiment, but may be the same. Any valve that can perform its function may be used.

As detailed above, according to the present invention, since the hammer ram is directly connected to the piston rod of the hydraulic cylinder attached to the upper end of the casing, the lifting force of the hammer ram can be increased, and the hammer ram can be made large and fall. The height can be shortened. For this reason, the casing was made smaller,
Can be made compact. Furthermore, by reducing the falling height, the time required for the hammer ram to rise and fall can be shortened, thereby reducing the time interval between pile driving and improving work efficiency.
Furthermore, when the hammer ram falls, the hydraulic oil in the piston rising chamber is flown toward the piston descending chamber by an electromagnetic one-way valve and a short relief passage, allowing the hydraulic oil in the piston rising chamber to escape smoothly. At the same time, the piston descending chamber is filled with hydraulic oil at high speed, and the falling of the hammer ram is not inhibited, high falling energy is generated, and the hose connecting the hammer and the ground side can be used as a small pipe. There are advantages.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall sectional view, FIG. 2 is a sectional view taken along the line - in FIG. 1, FIG. 3 is a piping system diagram of a hydraulic cylinder, and FIG. The figure is a sectional view showing the configuration of a one-way valve. DESCRIPTION OF SYMBOLS 1...Casing, 2...Sliding arm, 4...Blowing body, 9...Holder, 12...Hammer ram, 15...
Hydraulic cylinder, 16... Piston, 17... Piston rod, 20... Piston ascending chamber, 21... Piston descending chamber, 22... Ascending side passage, 23... Descending side passage,
29... Relief passage, 30... Solenoid type one-way valve.

Claims (1)

[Claims] 1. A holder in which a striking body is movable up and down at the lower end of a cylindrical casing that is slidably guided to a leader via a sliding arm protruding from the outer surface, and a pile head is connected to the lower end of this striking body. In addition to establishing
A hammer ram for hitting the striking body is provided in the casing so as to be movable up and down, a hydraulic cylinder is fixedly installed at the upper end of the casing, and a piston rod of the hydraulic cylinder is connected to the hammer ram,
The piston ascending chamber and the piston descending chamber in the hydraulic cylinder are communicated with the hydraulic pump through an ascending passage and a descending passage, respectively, via a switching valve, and the ascending passage and the descending passage are close to the hydraulic cylinder. It is connected by a relief passage equipped with an electromagnetic one-way valve that allows hydraulic oil to flow only from the ascending passage to the descending passage. A hydraulic drop hammer for pile driving, characterized in that the hydraulic oil in the piston ascending chamber is released into the piston descending chamber to cause the hammer ram to fall.