JPS6360173B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a noiseless and vibrationless pile driver that uses a working fluid such as pressure oil.

[Conventional technology]

As is well known, the various machines used in construction work have recently become larger and larger, making it possible to greatly improve the efficiency of construction work. As the size increases, the impact noise and vibrations generated during work also increase proportionally, which harms the living environment around the construction site, and is a major social problem, especially in urban areas, along with automobile exhaust gas pollution. It is becoming.

In particular, the operating noise, impact noise, and vibrations emitted by pile drivers used in foundation construction are significant, which is a serious problem, and a solution to these problems is strongly desired.

In view of these circumstances, in recent years, pile driving in urban areas has been done without using methods such as drop hammers, easel pile hammers, or vibrating pile drivers (vibro), which emit operating noises, impact noises, and vibrations. Press-in methods using winches and hydraulic cylinders that do not generate vibrations, press-in methods with screw augers, and pre-backed pile methods such as the PIP method have come to be used.

[Problem that the invention seeks to solve]

However, although these construction methods can eliminate operating noise, impact noise, and vibration, on the other hand, piles are driven without being able to confirm the bearing capacity, so it is difficult to follow the specified design. It is not known whether or not the building will have the supporting capacity, and in some cases there is a serious risk that the foundation may become defective and cause the building to tilt or collapse due to an earthquake.

Therefore, in this invention, it is possible to drive while checking the supporting force like a drop hammer, a diesel hammer, or a vibrating pile driver, and at the same time, it eliminates the operating noise and impact noise like a drop hammer, a diesel hammer, or a vibrating pile driver. A technical problem is to provide a noiseless and vibrationless pile driver that can suppress vibrations to the minimum level without emitting any noise.

[Means for Solving the Problems] In order to solve the above technical problems, the present invention consists of a double wall of an inner cover 1a and an outer cover 1b,
A casing 1 provided with an anvil 6 having a cushioning material 5 inside the lower end, a cylinder 9 supported by a plurality of hanging supports 8 provided on an inner cover 1a above the inside of the casing 1, It is formed by a piston 13 fitted into the cylinder 9 at a position above the working fluid supply port 9' bored in the lower part, a gap formed on the outer periphery of the lower part of the piston 13, and an inner surface of the cylinder 9. A working fluid chamber 15, which is a cavity, and whose lower end communicates with the working fluid supply port 9' and whose upper end communicates with a discharge port 27 formed in the stepped portion 26 of the piston 13; A spool valve 19 fitted therein opens and closes the discharge port 27, and a piston rod 12 that slides a rod 16 vertically installed below the piston 13 and connected to the spool valve 19 inside the shaft hole 17 of the shaft center.
The small cylinder 20 slides through the shaft hole of the small cylinder 20 which is screwed into the piston rod 12, and its upper end is connected to the lower end of the rod 16 of the spool valve 19 with its outer periphery stretched by a compression type coil spring 23. The working fluid chamber 1 is a space formed at the lower end of the small piston 21 and is supplied with working fluid.
6', a ram 11 which clamps the flange portion 20' of the small cylinder 20 by the cushion rubber plates 32, 32' and is fixed to the fixed plate 33 and freely slides within the casing 1, and the spool valve 19. The circuit for the working fluid that moves up and down includes oil supply circuits 37 and 37' that supply working fluid from the hydraulic pump 43 to the working fluid chamber 15, and a two-position four-way electromagnetic switching valve provided between these two circuits. 42, and the working fluid from the hydraulic pump 43 is transferred to the working fluid chamber 16'.
Spool valve drive circuit 46 and oil supply circuit 4
4, a two-position four-way electromagnetic switching valve 45 provided between both circuits, and an oil flow hole 18 on the upper end surface of the piston 13 provided at the upper part of the cylinder 9 communicate with each other to supply working fluid when the piston 13 rises. A temporary storage tank 30 is provided for storing working fluid and discharging the working fluid to the upper end surface of the piston 13 when the piston 13 descends, and the two-position four-way electromagnetic switching valve 45 is switched to communicate the spool valve drive circuit 46 and the oil supply circuit 44. , by switching the two-position four-way electromagnetic switching valve 43 to connect the oil supply circuits 37 and 37', raising the spool valve 19 and hence the ram 11, and communicating the oil supply circuit 37' to the oil tank 36. At the same time, the two-position four-way electromagnetic switching valve 42 is switched, and the two-position four-way electromagnetic switching valve 45 is switched so that the oil supply circuit 44 is communicated with the oil tank 36, and the spool valve 19 is switched.
Therefore, the hydraulic circuit for lowering the ram 11 and the excitation coil 6 of the two-position four-way electromagnetic switching valve 42, 45 are required.
The present invention is characterized by comprising a switching mechanism of both electromagnetic switching valves 42, 45 equipped with a timer 52 that operates the relays 53, 54 provided in the excitation circuits 5, 66 at a desired cycle by the rotation of a variable speed motor. It is configured as a noiseless and vibrationless pile driver.

[Effect]

Since the present invention is constructed as described above, it operates as follows.

Switch the two-position four-way electromagnetic switching valves 42 and 45,
The spool valve drive circuit 46 and the oil supply circuit 44 are communicated, and the working fluid from the oil pump 43 is transferred to the small piston 2.
When the hydraulic fluid is supplied to the working fluid chamber 16' of the cylinder 9, the spool valve 19 closes the discharge port 27 of the piston 13, while communicating the oil supply circuits 37 and 37', allowing the working fluid from the oil pump 43 to flow into the working fluid chamber of the cylinder 9. 15, piston 13 and ram 11
rises. As the piston 13 rises, the working fluid accumulated on the upper end surface of the piston 13 is temporarily stored in the storage tank 30.

After the ram 11 has risen to a certain stroke, when the two-position four-way electromagnetic switching valves 42 and 45 are switched,
The oil supply circuit 44 and the oil tank 36 communicate with each other, and the working fluid in the working fluid chamber 16' is discharged to the oil tank 36.
The spool valve 19 opens the discharge port 27 of the piston 13, and the oil supply circuit 37' and the oil tank 36 communicate with each other, so that the working fluid in the working fluid chamber 15 is transferred to the oil tank 36.
Also, the working fluid stored in the temporary storage tank 30 is discharged to the upper end surface of the piston 13, so that the piston 13 does not receive negative pressure, and the piston 13 and the ram 11 fall due to the weight of the ram 11. I will do it.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. In FIGS. 1 to 3, 1 is a double-walled casing in which an inner cover 1a is connected by a flange 3 and an outer cover 1b is provided on the outer periphery of the casing 1. An anvil 6 to which a cushioning material 5 such as rubber is attached is fixed with bolts 7, and a cylinder 9 is suspended and fixed to a plurality of suspension supports 8 fixed radially in the upper part. Reference numeral 10 denotes a cylinder cover that encloses the cylinder 9 and is integrally connected to the casing 1. A piston 13 is fitted into the cylinder 9, and a piston rod 12 is suspended below the piston 13. The piston rod 12 hangs outward from the lower end of the cylinder 9, and a ram 11 is suspended from the lower end. An oil plug 14 with a seal 34 is fitted into the lower end of the cylinder 9, and is in liquid-tight engagement with the piston rod 12.
A working fluid chamber 15 for raising the piston 13 is formed between the two. Reference numeral 9' denotes a working fluid supply port which is bored in the lower part of the cylinder and supplies working fluid such as pressure oil to the working fluid chamber 15. On the other hand, the piston 13 is an annular body having a seal 34',
Further, the piston rod 12 also has a shaft hole 17 at its axis, and a spool valve 19 connected to the rod 16 passing through the shaft hole 17 is fitted below the piston 13. The spool valve 19 has an air vent hole 28 to facilitate its movement, and its upward movement is restricted by a step 26 below the piston 13. Reference numeral 27 denotes a plurality of discharge ports of the piston 13 that communicate with the oil flow hole 18 in the center of the piston 13, the working fluid chamber 15 formed by the gap on the outer periphery of the lower part of the piston 13, and the inner surface of the cylinder 9, and a spool valve. 19 is moved up and down to close and open, and when opened, it communicates with the working fluid chamber 15, allowing the working fluid to be discharged into the oil flow hole 18 of the piston 13.

Reference numeral 4 denotes a lid fitted onto the lower end of the cylinder 9 and the oil plug 14.

A spool valve actuator 80 (FIG. 3) for driving the spool valve 19 is provided at the lower end of the rod 16.

That is, the rod 16 of the spool valve 19 has a narrow rod portion 16'' formed at its lower portion, and a small piston 21 is connected below the narrow rod portion 16''.

In addition, the lower female thread 12' of the piston rod 12
The upper male thread 20'' of the small cylinder 20 is screwed onto the cylindrical stopper 22.The inner cylindrical surface of the cylindrical stopper 22 is loosely fitted above the narrow rod portion 16'' of the rod 16, and the outer circumferential surface has a male thread 22'. The female thread 2 of the small cylinder 20
It is screwed to 0.

Coil spring 2
3 is housed so as to be wound around the narrow rod portion 16'' of the rod 16.

The small cylinder 20 is fitted into the center hole 11a of the ram 11 with the upper and lower annular cushion rubber plates 32, 32' fitted through the flange portion 20', and then the annular fixing plate 33 is inserted into the center of the ram 11. Hole 1
1a, the flange portion 20' of the small cylinder 20 and the cushion rubber plates 32, 32' are pressed against the central hole 11a of the ram 11 and fixed.

Flange portion 20' of piston rod 12 extension
The configuration in which the piston 13 and the ram 11 are sandwiched between the cushion rubber plates 32 and 32' has a great effect on vibration and soundproofing of the piston 13 and the ram 11 as a whole, and has a great effect on increasing the life of the machine. There is.

A working fluid chamber 16' is formed between the small cylinder 20 and the small piston 21. 25 is a conduit for supplying and discharging working fluid to the working fluid chamber 16';
Stoppers 22 and 24 hermetically seal the upper and lower ends of the small cylinder 20 to restrict the movement of the small piston 21. And the small piston 21 is a coil spring 2
3, the rod 16 moves downward and the spool valve 19 opens the discharge port 27. Reference numeral 31 denotes air vent holes formed in the upper and lower circumferential surfaces of the inner cover 1a and the flange 3, respectively, to reduce air resistance by moving the air inside the casing 1 so that the ram 11 moving up and down inside the casing 1 can easily operate. This reduces the Note that 35 indicates an O-ring. As shown in FIG. 1, the upper end of the cylinder 9 is provided with an external discharge port 29 and a temporary storage tank 30 that opens to the atmosphere. In addition, a portion is connected to an oil tank 36 (FIG. 4), which will be described later. The spool valve 19 discharges the working fluid from the working fluid chamber 16' to the conduit 25 and the coil spring 23.
The small piston 21 descends due to the urging force of , the discharge port 27 is opened, and when the ram 11 starts to fall under its own weight, the spool valve 19 flows into the cylinder 9 from the discharge port 27 opened. The working fluid is supplied again to the oil tank 36 via the working fluid supply port 9'.
discharge to. Then, when the piston 13 starts to descend again, working fluid is supplied to the upper part of the piston 13 in the cylinder 9 from a temporary storage tank 30 that is connected to an oil tank 36 that is open to the atmosphere and that is located close to the cylinder 9. . These structures will be described later with reference to FIG. As a result, when the piston 13 ascends, the working fluid accumulated in the upper part of the piston 13 flows into the temporary storage tank 30 above it, and when the piston 13 descends, the working fluid in the upper part of the piston 13 is in a negative pressure state due to the rapid descent. Temporary storage tank 30 is at close range.
Since the working fluid is replenished from the piston 13 to prevent the pressure from becoming negative, there is almost no resistance when the piston 13 descends, and this temporary storage tank 30 exhibits a great effect.

In this embodiment, the hammer action is achieved by repeatedly and continuously raising and lowering the piston 13. Next, the piston rod 12 and the piston 13 are raised and lowered alternately and continuously. The configuration of the hydraulic circuit will be explained below.

As shown in FIGS. 4 and 5, this hydraulic circuit includes a hydraulic pump 43 and a two-position four-way electromagnetic switching valve 4.
2 and the working fluid chamber 15 formed between the two-position four-way electromagnetic switching valve 42 and the inner surface of the cylinder 9 and the lower outer periphery of the piston 13. The working fluid chamber 15
an oil supply circuit 37' for supplying oil to the hydraulic fluid chamber 15, and a discharge port 27 for discharging the working fluid in the working fluid chamber 15 to the temporary storage tank 30 through the operation of the spool valve 19;
a circulation circuit 39 that circulates the working fluid in the upper part of the piston 13 of the cylinder 9 to the oil supply circuit 37;
Similarly, a communication circuit 40 connecting the upper part of the piston 13 of the cylinder 9 and the temporary storage tank 30, a discharge circuit 41 that discharges the working fluid in the temporary storage tank 30 to the oil tank 36, and a small cylinder that operates the spool valve 19. 20 and two-position four-way solenoid switching valve 45
a spool valve drive circuit 46 that connects the oil feeding circuit 37 and the two-position four-way electromagnetic switching valve 45, and a two-position four-way electromagnetic switching valve provided between the oil feeding circuits 37 and 37'. a circulation circuit 47 connecting the valve 42 and the discharge circuit 41; and a discharge circuit 63 connected by the switching port of the two-position four-way electromagnetic switching valve 45 and having the other end connected to the discharge circuit 41.
and a drain circuit 49, one end of which is connected to the switching port of the two-position four-way electromagnetic switching valve 45, and the other end of which is connected to a pilot operating valve 48 provided in the circulation circuit 39. two-position four-way electromagnetic switching valves 42 and 4 provided in the hydraulic circuit;
5 transfers the working fluid to the cylinder 9 by switching ports.
Oil supply circuit 37' that supplies the working fluid to the working fluid supply port 9'.
and an oil supply circuit 4 that supplies oil to the spool valve operating section 80.
The switching is performed so as to produce 4. Therefore, as shown in FIG.
By switching ports with the two-position four-way electromagnetic switching valve 45 provided in the 2-position four-way electromagnetic switching valve 45, the working fluid sent via the hydraulic pump 43 is sent to the working fluid chamber 15, and the working fluid is also sent to the working fluid chamber 16' of the small cylinder 20. When the spool valve 19 closes the discharge port 27, the piston 13 is raised.

In addition, at this time, the working fluid accumulated in the upper part of the cylinder 9 is temporarily stored in the storage tank 30 and in the circulation circuit 39.
flows to.

In addition, as shown in Fig. 5, a two-position four-way electromagnetic switching valve 4
When ports 2 and 45 are switched, oil tank 36
The working fluid is not sent to the cylinder 9, but flows to the oil tank 36 from the circulation circuit 47 connecting the two-position four-way electromagnetic switching valve 42 and the discharge circuit 41, and at the same time the oil feeding to the cylinder 9 is stopped. , the working fluid from the spool valve drive circuit 46 is supplied to the oil supply circuit 4.
The oil does not flow into the oil tank 36 through the drain circuit 49 connecting the pilot operating valve 48 provided in the circulation circuit 39 through the circulation circuit 39 → circulation circuit 47 → discharge circuit 41, and is sent to the small cylinder 20. is stopped, the working fluid in the working fluid chamber 16' flows to the oil tank 36 via the oil supply circuit 44 → the discharge circuit 63 → the discharge circuit 41, and the working fluid in the working fluid chamber 15 flows into the oil supply circuit 37'. →Circulation circuit 47→Flows to oil tank 36 via discharge circuit 41. As a result, the rod 16 is returned by the coil spring 23, the discharge port 27 is opened by the spool valve 19, and the working fluid chamber 15 and the temporary storage tank 30 are brought into communication, so that the pressing force on the piston 13 becomes zero. Eventually, the weight of the ram 11 overcomes it, and the piston 13 descends as the ram 11 rapidly falls free.

In addition, when the piston 13 ascends, the overflowing oil in the temporary storage tank 30 is transferred to the oil tank 36 from the discharge circuit 41, and when the piston 13 descends, the working fluid discharged from the upper part of the cylinder 9 is transferred to the circulation circuit 39 → two-position four-way electromagnetic circuit. It flows to the oil tank 36 via the switching valve 42 → circulation circuit 47 → discharge circuit 41.

In addition, in the figure, 55 is an electric motor, 56 is a chain coupling, 57 is a relief valve, 58 is a discharge circuit,
59 is a check circuit, 60 is a gauge valve, 61 is a pressure gauge, 62 is a check valve, and 64 is a filter.

A switching mechanism for alternately operating the two-position four-way electromagnetic switching valves 42 and 45 at a desired cycle, which are operated when the piston 13 is raised and lowered as described above, will be explained using a relay circuit 50 shown in FIG. do. 52 is a timer that opens and closes the excitation coils 65 and 66 of the relays 53 and 54, and when the push button switch 51 is turned on, the relays 53 and 54 are activated periodically by the rotation of the variable speed small motor, and the rotation of the motors is also changed. relays 53, 54
can change the operating cycle.

The rotary switch built into the timer 52 operates, and the relay contacts of the relays 53 and 54 open and close, and the excitation coils 65 and 66 open and close.
Periodically repeats standstill and operation. Excitation coil 65
The excitation coil 66 operates the two-position four-way electromagnetic switching valve 42, and the exciting coil 66 operates the two-position four-way electromagnetic switching valve 45.

The operation of the electrical system will now be explained with reference to FIGS. 6, 4, and 5.

First, when you turn on the push button switch 51, the timer 52 starts.
begins to rotate, but relays 53 and 54
When the relay contact is open as shown in the figure, no current flows through the excitation coils 65 and 66, so the two-position four-way electromagnetic switching valves 42 and 45 are in the state shown in FIG.
As described above, the hydraulic pressure pushes up the piston 13 and therefore the ram 11 rises. Next, when the timer 52 continues to rotate and current flows through the excitation coils 65 and 66 of the relays 53 and 54, the relays 53 and 54
is closed, current flows through the excitation coils 65 and 66, and the two-position four-way electromagnetic switching valves 42 and 45 are switched to the position shown in FIG. 27 and the hydraulic pressure that was pushing up the piston 13 becomes zero, causing the piston 13 and therefore the ram 11 to fall under their own weight, as described above. The rotary switch is set so that when the push button switch 51 is opened, the contact position of the rotary switch always remains at the open position as shown in FIG.

The above-described rise and fall are repeated by the timer 52, but by changing the rotation of the motor of the timer 52, the striking period of the ram 11 can be changed as desired.

Next, to briefly describe the method of installing and operating the pile driver of the present invention, the method of installing and operating the pile driver is the same as that of a known drop hammer, but as shown in FIGS. 7 and 8, A clamping guide 67 provided at the top and bottom of one side of the casing 1
is fitted onto the rail 69 of the leader 68 of the pile driver, and the tip of the wire rope 70, which is wound around the drum of a winch installed on the crane truck (not shown) and is suspended from the tip of the boom of the crane truck, is attached to the rail 69 of the leader 68 of the pile driver. The anvil 6 is suspended and installed by being connected to a sheep 71 provided in the casing 1, and the lower end surface of the anvil 6 is crowned on the head of the pile 72 by the winding and unwinding drive of the winch. By setting the cap 73 in contact with the upper end surface and operating it as described above, as the pile 72 is driven in, the casing 1 is gradually lowered by operating the winch in consideration of the driving force. All you have to do is make it .

Note that it goes without saying that only the mechanical components are mounted within the casing 1, and the operating hydraulic circuit portion is mounted on an operating vehicle or the like, and these are connected by a pressure hose or the like.

〔Effect of the invention〕

According to the invention described above, since the casing completely encloses the mechanical operating part, operating noise and impact noise do not leak directly to the outside.Furthermore, since the anvil is provided with a cushioning material, impact noise is reduced, and the spool The ram rises and falls under its own weight when the valve is driven, so there is less of a source of explosion noise as with conventional diesel pile hammers or vibrations as with vibrating pile drivers, and the pile driving operation is controlled by the ram's own weight. Because of this, it is of course possible to erect piles while checking the supporting capacity in the same way as conventional drop hammers, easel pile hammers, or vibrating pile drivers. Furthermore, the impact force can be easily set according to the soil conditions by simply adjusting the switching setting time of the timer 52 for the switching operation of the two-position four-way electromagnetic switching valves 42 and 45 forming the switching mechanism. It has the features of a very simple structure and a low occurrence of failures.
In addition, this double wall structure protects the machine from external forces.In addition, by closing the air vent hole and increasing the gap between the ram and the inner cover and providing a separate guide for the ram, the double wall structure can be Soundproofing can also be achieved by filling the walls with liquid, sand, or other fillers.

Furthermore, according to this invention, the operating vibration generated by itself is extremely small compared to a diesel pile hammer or a vibrating pile driver, and since a cushioning material is interposed in the anvil, vibration can be kept to a minimum. In addition, since the casing encloses the cylinder, there is no possibility of oil scattering to the outside like with diesel pile hammers, so there is the advantage that work can be carried out safely without any harm from scattered oil. It is extremely valuable as a pile driver.

It should be noted that the present invention is not limited to the structure of the embodiment, and it goes without saying that various design changes may be made without departing from the technical idea set forth in the claims.

[Brief explanation of the drawing]

Fig. 1 is a partially longitudinal side view of an embodiment of the present invention, Fig. 2 is an enlarged longitudinal side view showing the lower part of the cylinder, Fig. 3 is an enlarged longitudinal side view showing the lower part of the piston rod, and Fig. 4 5 and 5 are respectively hydraulic circuit diagrams, FIG. 6 is a relay circuit diagram, FIG. 7 is a plan view showing the installed state of the device of the present invention, and FIG. 8 is a side view thereof. 1... Casing, 1a... Inner cover, 3...
Flange, 1b... Outer cover, 5... Cushioning material, 6
...Anvil, 7...Bolt, 8...Hanging support, 9...
Cylinder, 9'... Working fluid supply port, 10... Cylinder cover, 11... Ram, 12... Piston rod, 13... Piston, 14... Oil plug, 1
5, 16'... Working fluid chamber, 16... Rod, 1
7...Shaft hole, 18...Oil distribution hole, 19...Spool valve, 20...Small cylinder, 20'...Flange part, 21...Small piston, 22...Stopper, 2
3...Coil spring, 24...Stopper, 2
5...Pipeline, 26...Step part, 27...Discharge port, 2
8...Air vent hole, 29...External discharge port, 30...
...Temporary storage tank, 31...Air vent hole, 32,
32'...Cushion rubber plate, 33...Fixing plate,
34, 34'...Seal, 35...O ring, 3
6... Oil tank, 37, 37'... Oil supply circuit, 3
8... Discharge circuit, 39... Circulation circuit, 40... Communication circuit, 41... Discharge circuit, 42... Two-position four-way electromagnetic switching valve, 43... Hydraulic pump, 44... Oil feeding circuit, 45... Two-position four-way solenoid switching valve, 46...
Spool valve drive circuit, 47... Circulation circuit, 48...
...Pilot operating valve, 49...Drain circuit, 50
...Relay circuit, 51...Push button switch, 52...
...Timer, 53, 54...Relay, 55...Electric motor, 56...Chain coupling, 57...
Relief valve, 58...Discharge circuit, 59...Check circuit, 60...Gauge valve, 61...Pressure gauge, 6
2... Check valve, 63... Discharge circuit, 64... Filter, 65, 66... Exciting coil, 67... Sandwich type guide, 68... Leader, 69... Rail, 70... Wire rope, 71 ...Sheeb, 7
2...Pile, 73...Cap, 80...Spool valve operating section.

Claims (1)

[Claims] 1. A casing 1 consisting of a double wall of an inner cover 1a and an outer cover 1b, and provided with an anvil 6 having a cushioning material 5 inside the lower end, and a plurality of hanging supports provided on the inner cover 1a above the interior of the casing 1. body 8
a cylinder 9 supported by the cylinder 9; and a piston 13 fitted into the cylinder 9 at a position above the working fluid supply port 9' formed at the bottom of the cylinder 9.
and a cavity formed by a cavity formed on the outer periphery of the lower part of the piston 13 and the inner surface of the cylinder 9, the lower end of which communicates with the working fluid supply port 9',
a working fluid chamber 15 whose upper end communicates with a discharge port 27 formed in the stepped portion 26 of the piston 13; a spool valve 19 fitted in the piston 13 to open and close the discharge port 27; The piston rod 12 slides the rod 16 connected to the spool valve 19 in the shaft hole 17 of the vertically arranged shaft, and the small cylinder 20 slides in the shaft hole of the small cylinder 20 screwed with the piston rod 12, and its upper end is connected to the spool valve 19. A space formed at the lower end of a small piston 21 whose outer periphery is connected to the lower end of the rod 16 of the spool valve 19 by a compression type coil spring 23, into which working fluid is supplied. the chamber 16' and the flange portion 2 of the small cylinder 20;
0' is sandwiched between cushion rubber plates 32 and 32', and the ram 11 is fixed to the fixed plate 33 and freely slides inside the casing 1, and the spool valve 19
The circuit for the working fluid that moves up and down includes oil supply circuits 37 and 37' that supply working fluid from the hydraulic pump 43 to the working fluid chamber 15, and a two-position four-way electromagnetic switching valve provided between these two circuits. 42 and the working fluid from the hydraulic pump 43 to the working fluid chamber 1.
6', a spool valve drive circuit 46 and an oil supply circuit 44, a two-position four-way electromagnetic switching valve 45 provided between these two circuits, and an oil distribution circuit provided on the upper end surface of the piston 13 provided above the cylinder 9. A temporary storage tank 30 is provided which communicates with the hole 18 and stores the working fluid when the piston 13 rises, and discharges the working fluid to the upper end surface of the piston 13 when the piston 13 descends, and the two-position four-way electromagnetic switching valve 45 is switched to The valve driving circuit 46 and the oil supply circuit 44 are brought into communication, and the two-position four-way electromagnetic switching valve 42 is switched to communicate the oil supply circuits 37 and 37', thereby raising the spool valve 19 and therefore the ram 11, thereby raising the spool valve 19 and therefore the ram 11. The two-position four-way electromagnetic switching valve 42 is switched to communicate the oil circuit 37' to the oil tank 36, and the two-position four-way electromagnetic switching valve 45 is switched to communicate the oil supply circuit 44 to the oil tank 36. 19
Therefore, the hydraulic circuit for lowering the ram 11 and the excitation coil 6 of the two-position four-way electromagnetic switching valve 42, 45 are required.
It is characterized by comprising a switching mechanism of both electromagnetic switching valves 42, 45 equipped with a timer 52 that operates the relays 53, 54 provided in the excitation circuits 5, 66 at a desired cycle by the rotation of a variable speed motor. A noiseless and vibrationless pile driver.