JPS6140819B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to an internal combustion type vibration exciter used for press-fitting and pulling out steel sheet piles, H-shaped steel piles, steel pipe piles, etc. in quay walls, reclaimed land, river revetments, mountain retaining construction, etc. It is related to the device.

The present inventors have developed an alternative to the conventional vibratory pile driver used in this type of construction, which uses a prime mover to synchronously rotate a rotary shaft on which an eccentric weight is mounted to generate vibrations. We proposed an internal combustion type exciter that can be used reliably.

Figures 1 and 2 show such an exciter,
In Fig. 1, reference numeral 1 denotes a self-propelled crane truck equipped with a caterpillar etc., on which a crane 2 is mounted, a hook 4 is suspended from the tip of the crane 2 via a wire 3, and a shaft 5 and a coil spring, etc. An exciter 7 is suspended from the hook 4 via a shock absorber 6 formed therein. 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 provided with a 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 combustion 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 is substantially the same as that of a conventional diesel pile hammer, so a detailed description thereof will be omitted. A hook 20 is pivotally supported on the cylinder 7a, and is engaged with a stepped portion 21 provided on the piston 8 to prevent the piston 8 from falling. 22 is a trigger lever for operating the hook 20, to which the upper end of the operating wire is fixed.

A starting valve 23 is provided in the upper part of the air buffer chamber 9,
The starting valve 23 opens when high pressure air is sent from the pipe 24 and closes when the high pressure air escapes.
When opened, high pressure air is supplied to the air buffer chamber 9 via a tube 25 connected to a high pressure air source (not shown). 26 is a switching valve disposed in the cylinder 7a. When the knob 27 is pushed, high pressure air is sent to the pipe 24 from a pipe 28 connected to a high pressure air source (not shown), and when it is released, high pressure air is sent from the pipe 28. The high pressure air in the pipe 24 whose supply is cut off is released to the atmosphere.

Further, an exhaust valve 29 is disposed in the upper part of the air buffer chamber 9, and opens when high pressure air is sent from a pipe 30 connected to a high pressure air source (not shown), and air is released 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 inside 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. cause it to rise. At this time, high-pressure air is sent into the air buffer chamber from the pipe 30, and the exhaust valve 29 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 29 is closed, and the trigger lever 22 is rotated upward as shown by the solid line to lock the hook 20 to the stepped portion 21 of the piston 8. , fix the piston 8.

Next, when the knob 27 of the switching valve 26 is pressed, high-pressure air flows through the pipe 24 above the starting valve 23 and pushes down the starting valve 23, so that high-pressure air flows into the air buffer chamber 9 through the pipe 25. .

When high pressure air is sufficiently supplied to the air buffer chamber 9, the starting valve 23 is closed and the trigger lever 22 is rotated downward as shown by the dotted line.
The hook 20 is disengaged from the stepped portion 21 of the piston 8, 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 piston 8 moves up and down continuously.

In this way, the piston 8 repeatedly moves up and down within the cylinder 7a, thereby giving vibration to the exciter 7, which in turn gives vibration to the pile P held by the chuck A fixed to the exciter 7. The pile P is gradually penetrated into soft ground, etc., and the soft ground improving agent is sent through the inner middle part of the pile P.

However, in the above vibration exciter, the piston is driven in the vertical direction, and when started, the piston is pushed down by the air pressure in the air buffer chamber and the piston's own weight, and the piston begins to drive. ,
For the fuel in the combustion chamber to self-ignite, the pressure in the combustion chamber must be
30Kg/cm2 or ^more is required.

Therefore, the compressed air supplied to the air buffer chamber at startup requires high-pressure air of several tens of kg/cm ² , and a high-pressure compressor is required to procure it.

The present invention eliminates these drawbacks, and provides that the upper surface of the piston slidably fitted into the cylinder faces the air buffer chamber or the combustion chamber, and the lower surface faces the combustion chamber. In an internal combustion type exciter in which the combustion chamber is provided with an intake/exhaust hole and a fuel injection nozzle, an air pressure accumulation chamber is provided adjacent to the air buffer chamber or the combustion chamber on the upper surface side of the piston, and the air pressure The internal combustion type exciter is characterized in that the pressure accumulator and the air buffer chamber or the combustion chamber are communicated with each other through a starter valve, and its purpose is to generate only a few kg/kg.
The object of the present invention is to provide an internal combustion exciter equipped with a starting device that can be driven by cm ² of compressed air.

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

An air pressure accumulating chamber 40 is arranged in contact with and apart from the air buffer chamber 9, and the air pressure accumulating chamber 40 and the air buffer chamber 9 communicate with each other through a starting valve 23.

Since the illustrated exciter is constructed as described above, the piston 8 is raised to a predetermined position within the cylinder 7a and locked with the hook 20, and then the switching valve 2
Pressing the knob 27 of 6 causes high pressure air to flow in through the upper tube 24 of the activation valve 23, and by lowering the pressure on the activation valve 23, the air is injected through the tube 25 connected to a high pressure air source (not shown). High pressure air is caused to flow into the air buffer chamber 9. When high pressure air is sufficiently supplied to the air buffer chamber 9 in this way, when the starting valve 23 is heard and the trigger lever 22 is rotated downward as shown by the dotted line, the hook 20 is moved from the stepped portion 21 of the piston 8. The piston 8 is removed from the cylinder 7a.
Fall inside.

As the piston 8 falls, the pressure in the air buffer chamber 9 decreases, and when the pressure has sufficiently decreased to around atmospheric pressure, the starting valve 23 is closed.

On the other hand, the combustion chamber 10 becomes high temperature and high pressure due to adiabatic compression, and the cam 18 of the piston 8 and the cam lever 9
The fuel pump 12 operates in cooperation with the nozzle 11, and fuel is injected from the nozzle 11 and ignited and burned.

Thereafter, the piston 8 continues to move up and down in a process similar to that of the above-mentioned vibrator.

Now, if the energy required to start the exciter is E, and the energy at the position of the piston 8 is ignored, then
In a conventional exciter, E=P _A V ₁ (where P _A V ₁ is the pressure and volume of the air buffer chamber 9 when the piston 8 is engaged with the hook 20 and activated, respectively).

On the other hand, in the illustrated exciter according to the embodiment of the present invention,
E=P _B (V ₁ +V ₂ ) (P _B , V ₁ , and V ₂ here are the pressure and volume of the air buffer chamber 9 as well as the pressure accumulation chamber 40 when the piston 8 is locked to the hook 20 and activated. volume).

From both equations above, P _B /P _A =V ₁ /V ₁ +V ₂ , and the starting air pressure P _B in the exciter according to the embodiment of the present invention can be reduced by increasing the volume V ₂ of the pressure accumulation chamber 40. It is something.

For example, in the conventional example, when the pressure P _A = 30Kg/cm ² and the volume V ₁ = 1 in the air buffer chamber, consider the point at which the piston descends and the volume of the air buffer chamber increases 10 times. , the pressure at that point P _A =3Kg/
cm ² , which reduces the effect of the piston lowering speed and the applied pressure.

On the other hand, according to the present invention, the pressure in the air buffer chamber is P
Even if _B = 6Kg/ ^cm2 , if there is a pressure accumulation chamber with a volume 6 times that of the same chamber, even when the piston descends to the same position as above, the pressure inside the air buffer chamber will still be 4.2Kg. It maintains a pressure of about / ^cm2 , and its effect on the downward speed of the piston is greater than that of conventional systems.

The compressed air normally used at construction sites is 6 to 7
Kg/cm ² is the limit, and therefore a special high-pressure compressor is required with conventional exciter starting devices, but according to the present invention, air sources available at the construction site can be used. The exciter can be activated immediately, and costs can be reduced accordingly.

The present invention is not limited to the embodiments described above, and various design changes may be made without departing from the spirit of the present invention. The present invention is also applicable to such cases.

[Brief explanation of the drawing]

Figure 1 is a side view showing how the exciter is used;
The figure is a longitudinal cross-sectional view of an exciter which is the object of improvement in the present invention, and FIG. 3 is a longitudinal cross-sectional view showing an embodiment of the internal combustion type exciter according to the present invention. 7a...Cylinder, 8...Piston, 9...Air buffer chamber, 10...Combustion chamber, 23...Start valve, 4
0...Air pressure accumulation chamber.

Claims (1)

[Claims] 1 The upper surface of the piston slidably fitted into the cylinder faces the air buffer chamber or the combustion chamber, the lower surface faces the combustion chamber, and the combustion chamber has an intake/exhaust hole and a fuel injection nozzle. In an internal combustion type exciter, an air pressure accumulation chamber is provided adjacent to the air buffer chamber or combustion chamber on the upper surface side of the piston, and the air pressure accumulation chamber and the air buffer chamber or combustion chamber are connected to each other by a starting valve. An internal combustion type exciter characterized by being connected by.