JPH0630900Y2 - Pile driver hydraulic circuit - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a hydraulic circuit of a pile driver in which a weight for pile driving can be freely dropped by a small-capacity hydraulic pump. .

[Prior Art] In the conventional pile driving machine shown in FIG. 6, a swivel frame 2 is provided on an upper part of a traveling frame 1, and a leader 5 is held at a front part of the swivel frame 2 via an attachment 3. There is.

A winch 6 with a clutch is attached to the rear portion of the revolving frame 2, and a wire 7 of the winch 6 with a clutch is attached to a front surface of a reader 5 via a holder 10 so that the winch 6 can be moved up and down. The weight 11 is connected to the weight 11 and the weight 11 is wound up by the winch 6 with a clutch, and then the clutch of the winch 6 with a clutch is turned off.
Is free to fall and is designed to stake.

In addition, 12 is a cap that fits on the head of the pile when driving the pile, and 70 is a hydraulic winch.

However, the above-mentioned conventional pile driver has the following problems.

i) The winch 6 with a clutch is expensive.

ii) In the clutch winch 6, the mounting position is limited.

iii) The clutch portion of the winch 6 with a clutch has insufficient durability and requires skill in clutch operation.

iv) Since the wire 7 is exposed to the outside of the leader 5, the wire 7 bounces at the time of driving a pile, which is dangerous for work.

In order to solve the above problems, the inventor of the present application has devised a pile driver in which a winch with a clutch is not used and a weight is moved up and down using a hydraulic cylinder. This pile driver will be described with reference to FIG. 7. A shaft 13 extending in the front-rear direction is provided inside the upper portion of the leader 5, and an upper end of a main body of a hydraulic cylinder 14 extending vertically is pivotally attached to the shaft 13. A shaft 15 extending in the left-right direction is attached to the lower end of the piston rod 14a of the hydraulic cylinder 14, and a slide guide 17 that moves up and down along vertically extending guide rails 16 provided on the inner left and right sides of the reader 5 is attached to the shaft 15. ing.

The slide guide 17 has the guide rails 16 on the upper and lower portions.
Guide rollers 18a, 18b rolling along, and a slide hole 19 extending in the up-down direction in the middle portion, and a cushioning material 20 such as wood is bolted to the upper and lower ends of the slide hole 19 by a method such as bolting. Prepared for exchange.

A shaft 21 extending in the left-right direction is vertically inserted through a slide hole 19 of the slide guide 17, and both ends of the shaft 21 roll along a required number of elevating sheaves 22 and 23 and the guide rail 16. A guide roller 18c is rotatably attached.

A fixed sheave 24 is rotatably supported by a shaft 13 above the leader 5, and a wire 7 whose one end is fixed to the shaft 13 by an anchor 71 includes a lifting sheave 22, a fixed sheave 24, and a lifting sheave 23.
Alternately in this order, and after being further hung over the top sheave 9, the other end is connected to the weight 11.

When lifting the weight 11, the piston rod 14a of the hydraulic cylinder 14 is lowered. Then, the slide guide 17 at the tip of the piston rod 14a of the hydraulic cylinder 14 descends and pushes the shaft 21 downward with the cushioning material 20 at the upper end of the slide hole 19, whereby the elevating sheaves 22 and 23 are separated from the fixed sheave 24. That is, the other end of the wire 7 is pulled back by that amount, and the weight 11 rises.

When the weight 11 is dropped, the piston rod 14a of the hydraulic cylinder 14 is raised. Then, first, only the slide guide 17 is raised, and then the shaft 21 is brought into contact with the cushioning member 20 at the upper end of the slide hole 19 by its own weight of the weight 11, thereby raising and lowering sheaves 22, 23 to the fixed sheave 24. Since it approaches, the wire 7 is paid out accordingly and the weight 11 falls.

At this time, since the wire 7 is hung on four threads, the weight 11 falls by a distance four times as much as the amount of rise of the piston rod 14a (twice for two threads, six times for six threads, eight times for eight threads). If multiplied, it will be 8 times).

Further, by adjusting the moving amount of the piston rod 14a of the hydraulic cylinder 14, the drop height of the weight 11 can be adjusted.

[Problems to be Solved by the Invention] In the case of the pile driver shown in FIG. 7 as well, it is necessary to freely drop the weight 11 in order to improve work efficiency during pile driving. Piston rod of pressure cylinder 14
It is necessary to raise 14a at a speed faster than the free fall speed of the weight sufficiently quickly.

However, the hydraulic circuit that raises and lowers the piston rod is usually the basic circuit of the hydraulic pump → control valve → hydraulic cylinder → tank, and the moving speed of the piston rod is determined by the discharge amount of the hydraulic pump and the cylinder size. To be done. Therefore, in order to increase the moving speed of the piston rod, a hydraulic pump with a large discharge amount is required, and the equipment cost and operation / maintenance cost are high.

When the pile driver is small, the hydraulic pump is also small. However, in this case, it may not be possible to increase the moving speed of the piston rod of the hydraulic cylinder. It may happen that it cannot fall freely.

In view of the above-mentioned circumstances, the present invention provides a pile driver that lifts and lowers a weight using a hydraulic cylinder so that the weight can freely fall regardless of the size of the hydraulic pump. It was made for the purpose.

[Means for Solving the Problems] In the present invention, a required number of lifting sheaves are attached to a slide guide that can be moved up and down along a leader by a hydraulic cylinder, and a required number of fixing sheaves are fixed above the leader sheaves. In a pile driving machine in which a sheave is arranged, a wire whose one end is fixed at a predetermined position is hung on the fixed sheave and the lifting sheave, and a weight is suspended at the other end, the liquid supplied from the hydraulic pump flows. At least two flow paths are connected to a control valve capable of switching the direction, and one flow path is connected to the head side liquid chamber of the hydraulic cylinder, and the other flow path is connected to the piston rod of the hydraulic cylinder. The flow path is connected to the side liquid chamber, an accumulator is connected to the one flow path through a pilot switching valve and a counterbalance valve, and an electromagnetic switching valve is connected to the other flow path. A lot switching valve is connected by a flow path, and the pilot switching valve is switched when the flow path and the other flow path communicate with each other by switching the electromagnetic switching valve, and the accumulator is replaced by the counter balance valve. The pilot flow path is connected to the flow path connecting the pilot switching valve and the electromagnetic switching valve via the.

[Operation] During hammering, the electromagnetic switching valve is switched so that the other channel is connected to the channel connecting the electromagnetic switching valve and the pilot switching valve.

Thus, when the weight is raised during hammering, the control valve is switched to introduce the liquid from the hydraulic pump into the liquid chamber on the head side of the hydraulic cylinder from one channel to lower the piston rod. . At this time, pressure is accumulated in the accumulator through the pilot switching valve and the counter balance valve by the liquid flowing in one of the flow paths.

When dropping the weight during hammering, the control valve is switched to introduce the liquid from the hydraulic pump into the liquid chamber on the piston rod side of the hydraulic cylinder from the other passage. At this time, the pilot switching valve is switched through the electromagnetic switching valve, the flow channel, and the pilot flow channel by the pressure of the liquid in the other flow channel, and the liquid accumulated in the accumulator is the counter balance valve, the pilot switching valve, and the flow channel. , The electromagnetic switching valve and the other flow path are rapidly introduced into the piston rod side liquid chamber of the hydraulic cylinder.
Therefore, the piston rod rapidly rises by a required stroke, and the weight falls at a free fall speed.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention.

The control valve 27 is connected to the tip of the discharge flow passage 26 connected to the hydraulic pump 25, the flow passages 28 and 29 are connected to the control valve 27, and the flow passage 28, the variable flow rate adjusting valve 31 with the check valve 30, the flow A counterbalance valve 34 with a check valve 35, in which the channels 32 are sequentially arranged in series and the channels 32 are connected to the piston rod side liquid chamber 33 of the hydraulic cylinder 14, the channels 29 and the relief valve 36 are provided, and the check valve 35 is provided. The flow path 37, the variable flow rate control valve 39 with the check valve 38, and the flow path 40 are sequentially arranged in series to connect the flow path 40 to the head-side liquid chamber 41 of the hydraulic cylinder 14, and the liquid pressure of the flow path 28 is connected. Is connected to the flow path 28.

Connect the electromagnetic switching valve 43 as a selection valve in the middle of the flow path 32,
The electromagnetic switching valve 43 and the pilot switching valve 44 are connected by the flow path 45, the pilot flow path 46 that transmits the liquid pressure of the flow path 45 to the pilot switching valve 44 is connected to the flow path 45, and the flow path 37 is provided in the middle. The connected flow path 47 is connected to the pilot switching valve 44 via the check valve 48, the pilot switching valve 44 is connected to the flow path 49, the counterbalance valve 51 with the check valve 50, and the accumulator 53 via the flow path 52.
And the counter balance valve 51
The pilot flow path 54 is connected to the flow path 52.

The flow passage 55, the variable flow rate adjusting valve 57 with the check valve 56, and the flow passage 58 are sequentially connected in series to the relief valve 36 provided in the counter balance valve 34 portion, and the flow passage 28 is connected to the pilot flow passage 42 connecting portion. The return flow path to the tank 62 connected to the control valve 27 by connecting the position close to the control valve 27 and the flow path 55 by the flow path 60 equipped with the check valve 59.
The flow path 58 is connected to 61.

In the figure, 63 and 64 are check valves, 65 is a pump suction passage, and 66 and 67.
Is a bypass flow path, 68 is a switch for sending a switching command current to the electromagnetic switching valve 43, and 69 is an alarm lamp provided in an electric circuit from the switch 68 to the electromagnetic switching valve 43.

Next, the operation of the present invention will be described with reference to FIGS.

(I) When performing positioning by raising the weight by normal operation (operation when positioning the weight, etc .... The accumulator does not work) (see Fig. 2).

In this case, as described in FIG. 7, it is necessary to lower the piston rod 14a, but the lowering speed is a normal lowering speed. Therefore, the switch 68 is turned off and the electromagnetic switching valve 43 switches so that the flow paths 32 and 45 are blocked. Further, the control valve 27 is switched so that the discharge flow path 26 and the flow path 29 communicate with each other and the flow path 28 and the return flow path 61 communicate with each other. The liquid sucked from the tank 62 into the hydraulic pump 25 through the suction flow path 65 and discharged from the hydraulic pump 25 is a discharge flow path 26, a control valve 27, and a flow path.
29, check valve 35 of counter balance valve 34, flow path 3
7 、 Variable flow rate adjustment valve 39, Flow path 40, Hydraulic cylinder 14
Is introduced into the head-side liquid chamber 41 to lower the piston rod 14a. Since the flow rate of the liquid introduced into the head side liquid chamber 41 is adjusted by the variable flow rate adjusting valve 39, the piston rod 14a
The descending speed of is a predetermined speed corresponding to the adjusted liquid flow rate.

On the other hand, when the piston rod 14a descends, the hydraulic cylinder 14
The liquid discharged from the piston rod side liquid chamber 33 of the
2, check valve 30 of variable flow rate adjusting valve 31, flow path 28, control valve 27,
It is returned to the tank 62 through the return flow path 61. Then, when the piston rod 14a descends by a predetermined amount, the control valve 27 is switched to the neutral state. When the control valve 27 is switched to the neutral state, the liquid discharged from the hydraulic pump 25 will be discharged into the discharge passage 26 and the bypass passage.
It circulates through the 66, the control valve 27, the bypass flow passage 67, and the return flow passage 61 and returns to the tank 62.

(II) When positioning by lowering the weight by normal operation (see Fig. 3).

In this case, it is necessary to raise the piston rod 14a at a normal rising speed. Therefore, as in the case of (I), the control valve 27 is switched while the switch 68 remains off, and the discharge flow path is changed.
26 and the flow path 28 are communicated with each other, and the flow path 29 and the return flow path 61 are communicated with each other.

Therefore, the liquid discharged from the hydraulic pump 25 is
26, the control valve 27, the flow path 28, the variable flow rate adjusting valve 31, and the flow path 32 are introduced into the piston rod side liquid chamber 33 of the hydraulic cylinder 14 to try to raise the piston rod 14a. 3
Since the flow of the liquid of 7 is blocked by the check valve 35, the piston rod 14a cannot rise and the hydraulic pump 2
The discharge pressure of 5 rises, and the pressures of the discharge flow passage 26, the flow passages 28, 32, and the piston rod side liquid chamber 33 of the hydraulic cylinder 14 rise. As a result, the pressure of the liquid in the flow path 28 is transmitted to the counter balance valve 34 via the pilot flow path 42, and the counter balance valve 34 is switched so that the flow paths 37 and 29 communicate with each other.

When the flow paths 37 and 29 communicate with each other, the piston rod 14 is driven by the liquid introduced into the piston rod side liquid chamber 33 of the hydraulic cylinder 14.
a rises. Since the flow rate of the liquid introduced into the piston rod side liquid chamber 33 is adjusted by the variable flow rate adjusting valve 31, the rising speed of the piston rod 14a becomes a predetermined speed corresponding to the adjusted liquid flow rate.

On the other hand, when the piston rod 14a rises, the hydraulic cylinder 14
The liquid discharged from the head side liquid chamber 41 of the flow path 40, the check valve 38 of the variable flow rate adjusting valve 39, the flow path 37, the counter balance valve.
It is returned to the tank 62 through the 34, the flow path 29, the control valve 27, and the return flow path 61. Then, when the piston rod 14a descends by a predetermined amount, the control valve 27 is switched to the neutral state.

As described above, the height of the weight is adjusted by lowering or raising the piston rod 14a by a normal operation.

(III) When lifting the weight during hammering (operation in which the weight can freely fall due to the action of the accumulator) (4th
See figure).

When the switch 68 is turned on, the solenoid directional control valve 43 causes the flow passages 32 and 45 to flow.
Are switched to communicate with each other. In this state, the control valve 27 is operated to connect the discharge flow path 26 and the flow path 29, and to connect the flow path 28 and the return flow path 61. The alarm lamp 69 is turned on when the switch 68 is turned on.

The liquid discharged from the hydraulic pump 25 is discharged through the discharge passage 26 and the control valve.
27, flow path 29, check valve 35 of counter balance valve 34, flow path
37, variable flow rate adjustment valve 39, hydraulic cylinder 14 through passage 40
Of the flow path 37, 47, the check valve 48, the pilot switching valve 44, the flow path 49, the check valve 50 of the counter balance valve 51, the flow path 52. It is introduced into the accumulator 53 through and is accumulated in pressure.

The liquid discharged from the piston rod side liquid chamber 33 by the piston rod 14a is the same as in the case of (I), the flow passage 32, the check valve 30 of the variable flow rate adjusting valve 31, the flow passage 28, the control valve 27, the return flow. Return to tank 62 via road 61.

(IV) When dropping the weight during hammering work (see Fig. 5).

When the piston rod 14a descends to a predetermined position by the operation of (III), the control valve 27 is switched to connect the discharge flow path 62 and the flow path 28, and connect the flow path 29 and the return flow path 61. For this reason,
The pressure of the liquid discharged from the hydraulic pump 25 is the discharge flow path 26,
Control valve 27, transmitted to flow path 28, from flow path 28 to pilot flow path
The counterbalance valve 34 is switched via 42, and the flow path 2
8, the variable flow rate adjusting valve 31, while being introduced into the piston rod side liquid chamber 33 of the hydraulic cylinder 14 from the flow passage 32, acting on the pilot flow passage 46 from the flow passage 32, the electromagnetic switching valve 43, the flow passage 45. The pilot switching valve 44 is switched, and the flow paths 45 and 49 are in communication.

Further, when the pressure of the liquid in the accumulator 53 due to the accumulated pressure on the accumulator 53 in the operation of (III) becomes higher than the set pressure of the counter balance valve 51, the counter balance valve 51 is switched so that the flow paths 49 and 52 communicate with each other. Since the check valve 48 is provided, the accumulator 53 maintains the pressure accumulation state.

Thus, when the pilot switching valve 44 is switched and the flow paths 49 and 45 are communicated with each other as described above, the liquid accumulated in the accumulator 53 is instantaneously flowed through the flow path 52 and the counter balance valve 5.
1, flow path 49, pilot switching valve 44, flow path 45, solenoid switching valve 4
3. The fluid is supplied to the piston rod side liquid chamber 33 of the hydraulic cylinder 14 via the flow path 32. Therefore, as a result of the piston rod 14a rapidly rising by the required stroke, the weight is lowered at the free fall speed.

When the pressure of the accumulator 53 falls to the set pressure of the counter balance valve 51, the counter balance valve 51 switches to the shutoff state.

When the pressure in the piston rod side liquid chamber 41 and the flow paths 40, 37 rises above the set pressure of the relief valve 36, the relief valve 36 opens. Therefore, a part of the liquid in the flow path 37 flows from the flow path 37 through the relief valve 36 into the flow path 55, and a part of the liquid flowing into the flow path 55 enters the flow path 60 into the flow path 28. It is introduced into the piston rod side liquid chamber 33 of the hydraulic cylinder 14 from the flow path 28, the variable flow rate adjusting valve 31, and the flow path 32 together with the liquid from the hydraulic pump 25, and the inside of the piston rod side liquid chamber 33 becomes negative pressure. It is prevented that a part of the liquid in the flow channel 55 flows into the flow channel 58 from the variable flow rate adjusting valve 57.

Further, a part of the liquid in the flow path 37 flows into the return flow path 61 from the counter balance valve 34, the flow path 29, and the control valve 27, and returns to the tank 62 together with the liquid from the flow path 58.

The hydraulic circuit of the pile driver of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

[Effects of the Invention] As described above, according to the hydraulic circuit of the pile driver of the present invention, when the fluid pressure cylinder piston rod rises when the weight is dropped, the fluid accumulated in the accumulator is Since the fluid pressure cylinder is designed to replenish the piston rod side fluid chamber, the fluid pressure pump can quickly raise the piston rod by the required stroke even if the discharge amount is small. It is possible to freely drop the weight regardless of the weight, and because the hydraulic pump has a small discharge amount, a small capacity can be selected.
Operation and maintenance costs are low. Various excellent effects can be obtained.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of an embodiment of the present invention, and FIG.
Hydraulic circuit diagram when positioning is performed by raising the weight by normal operation in the hydraulic circuit shown in Fig. 3, and Fig. 3 is a case where positioning is performed by lowering the weight by normal operation in the hydraulic circuit shown in Fig. 1. Fig. 4 is a hydraulic circuit diagram for raising the weight in the hydraulic circuit of Fig. 1 in the hammer work, and Fig. 5 is a hydraulic circuit diagram in the hydraulic circuit of Fig. 1 for the hammer work. Fig. 6 is a hydraulic circuit diagram for lowering the pile. Fig. 6 is a side view of an example of a conventional pile driver that raises and lowers the weight by a winch with a clutch.
The figure is a perspective view of a pile driver in which the pile driver of FIG. 6 is improved so that a weight is lifted and lowered by a fluid pressure cylinder. In the figure, 14 is a hydraulic cylinder, 14a is a piston rod, 17 is a slide guide, 22 and 23 are lifting sheaves, 24 is a fixed sheave, 2
5 is a hydraulic pump, 26 is a discharge flow passage, 27 is a control valve, 28 and 29 are flow passages, 31 is a variable flow rate adjusting valve, 32 is a flow passage, 33 is a piston rod side liquid chamber, 34 is a counter balance valve, 37 is a flow path, 39 is a variable flow rate adjusting valve, 40 is a head side liquid chamber, 43 is an electromagnetic switching valve,
44 is a pilot switching valve, 45 is a flow path, 46 is a pilot flow path, 47 and 49 are flow paths, 51 is a counterbalance valve, 52 is a flow path, and 53 is an accumulator.

Claims (1)

[Scope of utility model registration request] 1. A required number of lifting sheaves are attached to a slide guide which can be moved up and down along a leader by a hydraulic cylinder, and a required number of fixed sheaves are arranged above the lifting sheaves of the leader. In the pile driving machine, the wire fixed at a predetermined position is hung on the fixed sheave and the elevating sheave, and the weight is hung at the other end so that the flowing direction of the liquid supplied from the hydraulic pump can be switched. At least two flow paths are connected to the control valve, one flow path is connected to the head side liquid chamber of the hydraulic cylinder, and the other flow path is connected to the piston rod side liquid chamber of the hydraulic cylinder, An accumulator is connected to the one flow path via a pilot switching valve and a counterbalance valve, and an electromagnetic switching valve is connected to the other flow path, and the electromagnetic switching valve and the pilot switching valve are connected by a flow path. Then, the pilot switching valve is switched when the flow channel and the other channel are communicated with each other by switching the electromagnetic switching valve, and the accumulator is connected to the pilot switching valve via the counter balance valve. And a pilot flow path connected to a flow path connecting an electromagnetic switching valve to the hydraulic circuit of a pile driver.