JPS60116906A - Weight driving method for hydraulic hammer - Google Patents

Abstract

PURPOSE:To improve efficiency, by a method wherein, when a pile is hammered by a weight, operation to feed pressure oil to a hydraulic cylinder is started through detecting of such hammering, and the weight is raised. CONSTITUTION:An approach switch 19 is attached to a hydraulic hammer 1, and a stroke timer 14' is started by means of an output (f) of the approach switch 19. An output (c) of a relay 15 is turned ON, and through turning ON of a solenoid valve 16, a control valve 6 is switched in a time lag tau1. Pressure oil from an oil pressure source 5 is fed to the piston lower chamber of a hydraulic cylinder 4 to raise a weight 2. This enables elimination of a useless time between completion of driving of a pile by means of the weight 2 and the starting of raising of the weight 2, resulting in the possibility to perform a high efficient work to drive the pile.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of driving a pile by supplying pressure oil to a hydraulic cylinder for raising the weight to push up the weight, and by releasing the pressure oil from the hydraulic cylinder to allow the weight to fall freely. This invention relates to a method for driving a weight in a hydraulic hammer.

A conventional method for driving a weight in a hydraulic hammer will be explained using a representative example. First, a representative example of the hydraulic hammer 1 will be explained schematically with reference to FIG. - A hydraulic pressure source 5 to a control valve 6 and a pipe line 7
When pressure oil is supplied through the pump, the weight 8I2 is pushed up, and when the lower piston chamber is communicated with the oil tank 8 and the upper chamber of the piston via the control valve 6 etc., the weight 2 falls freely and the cushion 9 is pushed up. The structure is such that a stake 11 is driven through the cap 10 having the cap 10.

The control valve 6 is controlled as follows. When the start switch 13 of the operating electric circuit 12 is pressed, the output a of the stroke timer 14 for setting the drop height is turned on as shown in FIG. 2, and the output C of the relay 15 is also turned on. Solenoid valve 1 as a valve
6 is turned on, and the control valve 6 is switched to the side that supplies pressure oil to the hydraulic cylinder 4 with a delay time τ1 by pilot pressure oil from the pilot I/hydraulic source 5'' (
That is, the pressure d in the pipe line 7 increases), the weight 2 rises as shown in e, and the set time T of the stroke timer 14 increases.
When l has passed, the output a is turned off, the output of the interval timer 17 is turned on, the relay 15 is turned off, the solenoid valve 16 is turned off, and the control valve 6 connects the pipe line 7 to the oil tank 8 with a delay time τ2. The position is switched and the weight 2 falls. Then, when the set time T2 of the interval timer 17 has elapsed, the interval timer 17 is turned off, the stroke timer 14 is turned on, and the weight 2 starts to rise again.

In such a method of driving the weight 2 of the hydraulic hammer 1,
In order to efficiently perform the work of driving piles 11, conventionally two weights were used.
Much effort has been devoted to how to make the fall approach free fall, or how to make it fall more rapidly. As a countermeasure against this, when the weight 2 falls, the flow passage cross-sectional area of the control valve 6 and the pipe line 7 for draining the pressure oil in the hydraulic cylinder 4 for raising the weight when the weight 2 falls, and the supply pipe line for draining the pressure oil are taken. What is
Adding a dedicated pipe for the outflow of Wll, applying atmospheric pressure, hydraulic pressure, spring pressure, etc. to the upper chamber of the piston of the weight 2 or hydraulic cylinder 4 when the pile ll falls, or evacuating the lower chamber of the weight 11. Proposals such as suctioning have been made. However, there is a lack of consideration regarding the interval of weight operation.

That is, in the conventional method of driving a weight, the stroke S) for increasing the height of the weight 2 is set by a stroke timer 14 that sets the pressure oil supply time T1 to the hydraulic cylinder 4 for lifting the weight, and In this method, the time T2 from when the weight 2 starts falling until the start of the next rise is set by the interval timer 17 to cause the weight 2 to rise and fall freely, and the set time TI of the two timers 14 and 17. , T2 are manually set by the operator.

However, according to this conventional method, the interval timer 17 for the set time TI of the stroke timer 14
When the operator manually sets the set time T2 of the interval timer 17, the set time T2 of the interval timer 17 is usually set longer than necessary from the viewpoint of work safety. For this reason, as shown by T3 in FIG. 2e, the dead time (the time delay compared to when the weight 2 starts to rise immediately after falling, as shown by the imaginary line 18) becomes longer. As a result, the number of times the pile is struck per unit time is reduced, resulting in poor work efficiency. In addition, if the setting time TI of the stroke timer 14 is shortened and the interval timer 1
After hitting the pile with a low stroke by shortening the stroke timer 14 due to changes in soil quality, pile length, pile type, etc.
When performing work with a high stroke by increasing the set time TI of the interval timer 17, if you forget to increase the set time T2 of the interval timer 17 and operate it, the control valve 6 will close to the pressure oil supply side while the weight 2 is falling. As a result, a large pressure due to the falling weight acts on the hydraulic cylinder 4, the pipe line 7, etc., and there is a risk of damaging various parts. Furthermore, when the stroke is changed by changing the set time TI of the stroke timer 14, the set time T2 of the interval timer 17 must also be adjusted in order to operate the weight 2 so that the dead time is shortened. The adjustment operations seem to be incorrect.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for driving a weight that allows the pile to be hit with a weight with high efficiency without wasting time, thereby increasing work safety.

In order to achieve this object, the present invention is characterized in that it detects that a single weight hits a pile, and in response to the detection signal, starts supplying pressure oil to the hydraulic cylinder to raise the weight. .

An embodiment of the present invention will be described below with reference to Figures 3 and 4. In FIG. 3, the same reference numerals as in FIG. 1 indicate the same components. In this embodiment, first, by operating the start switch 13 and turning on the output t of l, a stroke timer 14' whose set time is variable is activated, and the output a of the stroke timer 14' is turned on. This turns on the output C of the relay 15 and turns on the solenoid valve 16. As a result, the control valve 6 is switched with the time delay τ, and pressure oil from the hydraulic source 5 is supplied to the lower chamber of the piston of the hydraulic cylinder 4 via the pipe 7, and the weight 2 is moved to the position e in FIG. When the output a of the stroke timer 14'' is turned off after the time determined by the set time as shown in FIG. Since it returns to the position communicating with the chamber, the weight 2 falls and hits the pile 11 through the cap 10.

In this embodiment, the proximity switch 9 detects that the pile has been hit, and the output f of the proximity switch 19 is used to start the stroke timer 14'', and this operation is repeated thereafter. The proximity switch 19 is installed at the lower end of the weight 2 made of magnetic material when the load of the hydraulic hammer 1 is applied to the pile 11 via the cap lO and the weight 2 is placed on the cap 10. However, the proximity switch may be installed in a position where it is inactive at the pile striking position of m!!2 and activated at other positions.

In this way, by starting the operation of supplying pressure oil to the hydraulic cylinder 4, that is, the operation of raising the weight immediately after the weight 2 hits the pile 11, wasted time can be reduced. This makes it possible to perform pile driving work with high efficiency. -For example, a conventional stroke is 20
If the present invention is applied to a device that can be struck once per minute, it will be possible to make around 25 times per minute with the same stroke, which is approximately 25 times per minute.
It became possible to increase the number of hits by about %, and it was possible to significantly improve efficiency.

Note that when the pressure oil supply circuit to the hydraulic cylinder 4 is switched by the impact of the weight 2 on the pile 11, there is a delay time of 1 due to the hydraulic circuit, but the weight 2 hits the pile 1 and bounces. It will be more efficient if a delay action relay as shown at 22 in Fig. 3 is provided so that the pressure oil supply operation starts when the weight 2 rises due to this bounce (during Δt in Fig. 4). And there is no unreasonableness.

In addition, since the weight 2 starts the upward movement after striking the pile 11, the hydraulic circuit may be cut off in the direction of pushing up the weight while the weight 2 is descending due to an error in the time setting of the interval timer, as in the conventional case. On the other hand, there is no risk that extremely high pressure will be generated in the hydraulic cylinder 4 and the like and damage them, improving operational safety.

In this embodiment, the stroke is set using the stroke timer 14', but the height may also be set using a switch or the like. Figure 5 is an example of this, and the actuator is operated by a weight made of, for example, a magnetic material (or an electrostatic type or photosensitive A plurality of proximity switches 20a to 20c (in the form of 6, the start switch 13 turns on the relay 15, which turns on the solenoid valve 16 and switches the control valve 6.
Pressurized oil from the hydraulic source 5 is supplied to the hydraulic cylinder 4 and the weight 2 is
is raised, and when the proximity switch (one of 20a to 20d) selected by the selection switch group 21 is activated and outputs its output, the relay 15 is turned off, thereby turning off the solenoid valve 16. control valve 6
By returning to the original position, the weight 2 is dropped, and the weight 2
detecting the impact of the pile 11 by the proximity switch 19;
The output f turns on the relay 15. The subsequent operations are as described above. In addition, the proximity switches 20a to 20d
may be installed so that it is activated when the weight 2 hits the pile 11 and is inactivated when the weight 2 is raised, thereby forming a circuit.

In this way, as shown in FIG. 7, the stroke can be changed to S1, S2, S3, and S4 depending on which of the proximity switches 20a to 20d the operator selects.

Although the present invention has been described above using Examples, it goes without saying that various changes can be made without departing from the gist of the present invention. For example, means for detecting that the weight 2 hits the pile 11 include not only a proximity switch but also a detector for vibration or vibration acceleration of the hydraulic pressure regulator and surrounding equipment, and a detector for the impact sound. Or, a stroke meter consisting of a potentiometer whose output changes depending on the height of the weight can be used as long as it can detect a signal at the time of impact. Further, it is also possible to use the stroke meter to set the stroke. Further, it is also possible to implement the control portion such as the timer using a microcomputer. Additionally, the hydraulic hammer to which the present invention is applied is
Any structure may be used as long as the weight is raised by supplying pressure oil to the hydraulic cylinder and falls by removing the pressure oil, and the weight may also be a structure in which the weight also serves as the piston of the hydraulic cylinder.

□As described above, according to the present invention, it is possible to detect that the weight hits the pile, and to start supplying pressure oil to the hydraulic cylinder based on the detection signal to raise the weight. Therefore, it is possible to eliminate wasted time from the time when the pile is struck by the weight until the weight starts to rise, and it becomes possible to perform the pile driving work with significantly higher efficiency than in the past. In addition, since the start of the weight lifting operation is always performed after the pile is struck,
This eliminates the risk of damage to component equipment caused by high pressure being generated in the hydraulic cylinder or the like due to a setting error in the interval timer, as was the case in the past, and operational safety is improved. Further, according to the present invention, there is no need to take into account the interval time after the pile is struck, so there is no need to take the time and effort to set the interval time, which also helps improve efficiency.

[Brief explanation of drawings]

Figures 1 and 2 are a block diagram and a time chart of a hydraulic hammer explaining a conventional weight driving method, respectively;
4 and 4 are respectively a block diagram and a time chart of a hydraulic hammer explaining one embodiment of the weight driving method of the present invention, and FIGS. 5 and 6 are respectively another embodiment of the weight driving method of the present invention. FIG. 7 is a configuration diagram and a time chart of a hydraulic hammer to explain an example, and a waveform diagram to explain the action of the example. DESCRIPTION OF SYMBOLS 1... Hydraulic hammer, 2... Weight, 4... Hydraulic cylinder, 5... Control valve, 11... Pile, 13...
...Start switch, 14'...Stroke timer, 1
5... Relay, 16... Solenoid valve, 19.2
0a to 20d... Proximity switch, 21... Selection switch group Patent applicant Hitachi Construction Machinery Co., Ltd. Agent Patent attorney Masami Akimoto Agent Patent attorney Masaru Wakata - Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Procedural Amendment (Voluntary) June 4, 1980 Mr. Kazuo Wakasugi, Commissioner of the Patent Office1, Indication of the Case 1982 Patent Application No. 2233842, Name of Invention Method for Driving Weight of Hydraulic Hammer 3, Amendment Relationship with the case involving the person who filed the patent application Patent applicant address: 2-6-2 Otemachi, Chiyoda-ku, Tokyo Name:
(552) Hitachi Teiki Co., Ltd. Representative name: Nishimoto Bunpei 4, Agent address: 105

Claims (1)

[Claims] In a hydraulic hammer that drives piles by supplying pressure oil to a hydraulic cylinder for lifting the weight, the weight is pushed up, and by removing the pressure oil from the hydraulic cylinder, the weight drops to drive a pile. A method for driving a weight of a hydraulic hammer, characterized in that the weight is raised by detecting that the weight has been moved, and in response to the detection signal, an operation of supplying pressure oil to the hydraulic cylinder is started to raise the weight.