JPS6131249B2 - - Google Patents

Description

[Detailed description of the invention] The vibratory pile driver currently used in civil engineering work to press in and pull out large steel sheet piles, steel pipe piles, etc.
A structure in which eccentric weights are attached to one or more pairs of rotating shafts driven by a prime mover, and all rotating shafts are rotated synchronously to offset horizontal centrifugal force, and vibration is generated by vertical unbalanced force. It's getting old.

This vibratory pile driver has a simple structure and is an effective device, but the operation of the device usually requires an engine, power generation,
It required electrical control equipment, and as the machine became larger, it had the disadvantage of requiring a large amount of cost for the entire equipment.

In order to eliminate the above-mentioned drawbacks, instead of the conventional method of supplying fuel to the engine and converting the energy into electricity to drive the electric motor of the vibratory pile driver, it is possible to directly supply fuel to the vibratory pile driver, A vibratory pile driver has been proposed that drives piles while directly generating vertical vibrations using the combustion energy.

Figures 1 and 2 show such a vibrating pile driver. In Figure 1, 1 is a self-propelled crane truck equipped with a caterpillar etc., on which a crane 2 is mounted, and a crane 2 is mounted on it. A hook 4 is suspended via a wire 3, and an exciter 7 is suspended from the hook 4 via a shackle 5 and a shock absorber 6 formed of a coil spring or the like. The vibrator 7 is configured to grip the upper end of the steel pipe P via a chuck A provided at the lower end of the main body.

FIG. 2 shows details of the main body of the exciter 7, the inside of which forms a cylinder 7a, into which a piston 8 is slidably inserted, and the space above the piston 8 forms an air buffer chamber 9. , the lower space forms a combustion chamber 10.

A fuel injection nozzle 1 is provided on the lower end surface of the combustion chamber 10.
1 is disposed, and is connected via a fuel injection pipe 13 to a fuel pump 12 attached to the cylinder 7a.

On the side surface of the combustion chamber 10 of the cylinder 7a, an intake/exhaust hole 1 is provided for intake of air and discharge of combustion gas.
4 is provided, and an air buffer chamber 9 of the cylinder 7a is provided.
An air adjustment hole 15 for adjusting the amount of air is provided on the side surface.

The cylinder 7a is provided with a fuel chamber 16, which communicates with the fuel pump 12 through a fuel supply pipe 17, through which fuel is supplied.

The fuel pump 12 is a bottle type fuel pump used in internal combustion engines, and is driven by a cam 18 provided on the side of the piston 8 and a cam lever 19 pivotally supported on the cylinder 7a. There is. The driving mechanism of the fuel pump 12 is substantially the same as that of a conventional diesel pile hammer, so a detailed explanation will be omitted. 20 is cylinder 7a
A hook pivotally supported by the piston 8 is latched to a stepped portion 8a provided on the piston 8 to prevent the piston 8 from falling. 21 is a trigger lever for operating the hook 20, to which the upper end of the operating wire is fixed.

Next, the operation of the pile driver will be explained.

When the piston 8 is pulled up to the top inside the cylinder 7a, the operating trigger lever 21
When the hook 20 is removed from the stepped portion 8a, the piston 8 falls inside the cylinder 7a due to its own weight. When the piston 8 closes the intake/exhaust hole 14 and moves further down, the air in the combustion chamber 10 becomes high temperature and high pressure due to adiabatic compression.

At this time, the cam 18 of the piston 8 and the cam lever 1
9, the fuel supplied from the fuel pump 12 is injected from the nozzle 11 into the combustion chamber 10,
The same fuel ignites and burns. This combustion increases the pressure in the combustion chamber 10, and this pressure causes the piston 8 to rise within the cylinder 7a.

Thus, as the piston 8 rises, the intake/exhaust port 1
When 4 opens, combustion gas is exhausted and fresh air is sucked in.

On the other hand, as the piston 8 moves upward, the air within the air buffer chamber 9 is compressed, and due to the cushioning action caused by this compression, the piston 8 starts its downward motion again.

In this way, the piston 8 repeatedly moves up and down inside the cylinder 7a due to the explosive force of the fuel, giving vibration to the exciter 7, and the piston 8 is held by the chuck A fixed to the exciter 7. The pile P can be vibrated to gradually penetrate into soft ground, or
The soft ground improvement agent is delivered through the internal hollow part of the container.

However, when starting the vibratory pile driver,
Unlike diesel pile hammers, which start the pile by dropping the piston from a certain height, vibrating pile drivers make the stroke of the piston as short as possible, making it impossible to achieve the height necessary to ignite the fuel.

Furthermore, the method used in internal combustion engines to supply compressed air from a starter valve to the combustion chamber to move the pistons requires a flywheel and a complicated valve mechanism to continuously move the pistons, but the vibrator, which does not have a crankshaft, Recruitment is difficult.

The present invention eliminates these drawbacks, in that the lower side of the piston, which is slidably fitted in the cylinder, faces the combustion chamber and the upper side faces the air buffer chamber.
In the vibratory pile driver in which the combustion chamber is provided with an intake/exhaust hole and a fuel injection nozzle, the air buffer chamber is provided with an exhaust valve and a starting valve, and the exhaust valve is provided with an exhaust valve and a starting valve in the air buffer chamber as necessary. The vibratory pile driver is characterized in that the starting valve is provided with means for introducing high-pressure air into the air buffer chamber as required, and the purpose thereof is as follows: ,
An object of the present invention is to provide an improved vibratory pile driver that can be started up reliably.

The present invention will be described below with reference to an embodiment shown in FIG. In the figure, parts equivalent to the vibrating pile driver are given the same reference numerals.

A starting valve 31 is provided in the upper part of the air buffer chamber 9,
The starting valve 3 opens when high pressure air is sent from the pipe 32 and closes when the high pressure air escapes.
1 is opened, high pressure air is supplied to the air buffer chamber 9 via a tube 33 connected to a high pressure air source (not shown). 34 is a switching valve disposed in the cylinder 7a. When the knob 35 is pushed, high pressure air is sent from a pipe 36 connected to a high pressure air source (not shown) to the pipe 32, and when it is released, high pressure air is sent from the pipe 36. The supply of air is cut off, and the high pressure air in the pipe 32 is released to the atmosphere.

Further, an exhaust valve 37 is disposed in the upper part of the air buffer chamber 9, and opens when high pressure air is sent from a pipe 38 connected to a high pressure air source (not shown), and air is discharged from a relief valve (not shown). It closes when you pull it out.

Since the illustrated vibratory pile driver is constructed as described above, the piston 8 is moved into the cylinder 7a by a known method such as applying compressed air below the piston 8 or pulling up the piston 8 with a crane. to rise. At this time, high-pressure air is sent into the air buffer chamber from the pipe 38, and the exhaust valve 37 is pushed down and opened to evacuate the air from the air buffer chamber 9, thereby making it easier for the piston 8 to rise.

When the piston 8 rises to a predetermined position within the cylinder 7a, the exhaust valve 37 is closed, and the trigger lever 21 is rotated upward as shown by the solid line to lock the hook 20 to the stepped portion 8a of the piston 8. and fix the piston 8.

Next, when the knob 35 of the switching valve 34 is pressed, high-pressure air flows into the upper part of the starting valve 31 through the pipe 32, and as the starting valve 31 is pushed down, high-pressure air flows into the air buffer chamber 9 through the pipe 33. .

When high pressure air is sufficiently supplied to the air buffer chamber 9, the starting valve 31 is closed and the trigger lever 21 is rotated downward as shown by the dotted line, so that the hook 20 engages with the stepped portion 8a of the piston 8. The connection is released, and the piston 8 falls within the cylinder 7a.

As the piston 8 falls, the combustion chamber 10 becomes high temperature and high pressure due to adiabatic compression, and the cam 1 of the piston 8
8 and the cam lever 19, the fuel pump 1
2 is activated, fuel is injected from the nozzle 11 into the combustion chamber 10, and the fuel is ignited and combusted. When the fuel is ignited and burned, the pressure in the combustion chamber 10 increases and the piston 8 moves upward within the cylinder 7a.

As the piston 8 rises, the pressure in the air buffer chamber 9 increases, and due to its cushioning action, the piston 8 again switches to a downward motion, after which fuel ignition combustion in the combustion chamber 10 and the cushioning action of the air buffer chamber 9 occur. This is done alternately so that the vertical movement of the piston 8 is continuously performed.

In the vibratory pile driver according to the present invention, as described above, the air buffer chamber facing the upper surface of the piston slidably inserted into the cylinder is provided with an air buffer chamber as required. An exhaust valve equipped with a means for removing air from the air buffer chamber, and a startup valve equipped with a means for introducing high-pressure air into the air buffer chamber as necessary are provided. By filling the chamber with high-pressure air in advance, in addition to the natural fall due to the piston's own weight, pressure from air pressure is applied, increasing the falling speed of the piston within the cylinder, making ignition easier and reducing the stroke. Particularly effective for vibrating pile drivers.

Further, when the piston is pulled up into the upper part of the cylinder prior to starting, the air in the air buffer chamber is evacuated by the exhaust valve, so that the piston can be easily pulled up.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to such embodiments, and can be modified in various designs without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

Figure 1 is a side view showing how the vibratory pile driver is used;
FIG. 2 is a vertical cross-sectional view of a conventional vibratory pile driver, and FIG. 3 is a vertical cross-sectional view showing an embodiment of the vibratory pile driver according to the present invention. 7a...Cylinder, 8...Piston, 9...Air buffer chamber, 10...Combustion chamber, 31...Start valve, 3
7...Exhaust valve.

Claims (1)

[Claims] 1. A piston slidably fitted in a cylinder has a lower surface facing a combustion chamber, an upper surface facing an air buffer chamber, and an intake/exhaust hole and a fuel injection nozzle are disposed in the combustion chamber. In the vibratory pile driver, the air buffer chamber is provided with an exhaust valve and a starting valve, the exhaust valve is provided with a means for removing air from the air buffer chamber as necessary, and the starting valve is provided with a means for removing air from the air buffer chamber as necessary. A vibratory pile driver, comprising means for introducing high-pressure air into the air buffer chambers.