JPH0428852B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is capable of driving piles 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 drop the weight. 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 typical example of the hydraulic hammer 1 will be explained with reference to FIG. 1.
is vertically movably housed in a case 3 that is mounted vertically movably along the leader (not shown) of the pile driver, and is connected to a hydraulic cylinder 4 provided outside the case or inside the case as shown. A control valve 6 and a pipe line 7 are connected from the hydraulic source 5 to the piston lower chamber.
If pressurized oil is supplied through , the weight 2 will be pushed up,
When the piston lower chamber is communicated with the oil tank 8 and the piston upper chamber via the control valve 6 etc., the weight 2 falls freely and the cap 10 having the cushion 9 is connected.
It is configured such that the pile 11 is driven through the shaft.

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, which sets the falling height, is turned on and the output c of the relay 15 is turned on, as shown in FIG. Then, the solenoid valve 16 as a pilot valve is turned on, and the control valve 6 is switched to the side that supplies pressure oil to the hydraulic cylinder 4 after a delay time τ ₁ by the pilot pressure oil from the pilot oil pressure source 5' (i.e. , the pressure d in the pipe line 7 increases), the weight 2
increases as shown in e, and the stroke timer 14
When the set time T1 has elapsed, the output a turns off.
The output b of the interval timer 17 is turned on, the relay 15 is turned off, and the solenoid valve 16 is turned off, and with a time delay τ ₂ , the control valve 6 is switched to the position where the pipe line 7 is communicated with the oil tank 8, 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 driving work of the pile 11, conventional methods have been used to determine how to bring the fall of the weight 2 closer to free fall or how to make it fall rapidly. I've been putting in a lot of effort. And as a countermeasure,
When the weight 2 falls, the flow path cross-sectional area of the conduit 7 and control valve 6 for draining the pressure oil in the hydraulic cylinder 4 for lifting the weight may be increased, or a separate flow path from the supply conduit may be used to drain the pressure oil. Adding a dedicated conduit, applying air pressure, hydraulic pressure, spring pressure, etc. to the upper chamber of the piston of the weight 2 or hydraulic cylinder 4 when the pile 11 falls, vacuum suctioning the lower chamber of the weight 11, etc. proposals have been made. However, there is a lack of consideration regarding the interval of weight operation.

In other words, in the conventional method of driving a weight, the height of rise (stroke S) 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. Time T2 from when weight 2 starts falling until the next start of rising
is set by the interval timer 17 and the weight 2
This is a method of causing the ascent and free fall of
Manually set by the operator.

However, according to this conventional method, when the operator manually sets the set time T2 of the interval timer 17 with respect to the set time T1 of the stroke timer 14, from the viewpoint of work safety, the set time T2 of the interval timer 17 is is usually set longer than necessary. For this reason, as shown by T3 in Fig. 2e, the dead time (the time delay compared to when the weight 2 suddenly starts rising 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 decreases, resulting in poor work efficiency. Furthermore, if the stroke is changed by changing the set time T1 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 dead time is shortened. Adjustment operations are cumbersome.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for driving a weight in a hydraulic hammer, which allows the hammer to hit a pile with high efficiency without wasting time.

In order to achieve this objective, the present invention measures the time from the starting point of the lifting operation of the electric circuit or hydraulic circuit for driving the weight or from the time when the weight actually starts to rise until the time when the weight hits the pile. However, the present invention is characterized in that the suspension time of the rising operation of the electric circuit or hydraulic circuit in the next cycle or thereafter is controlled to be long or short in accordance with the length of the actual measurement time. Also,
In the present invention, the time from the starting point of the falling movement of the electric circuit or hydraulic circuit for driving the weight or the time when the weight actually starts falling to the time when the weight hits the pile may be used as the actual measured time. good.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. In FIG. 3, the same reference numerals as in FIG. 1 indicate the same components. In this example,
First, by operating the start switch 13 and turning on its output t, the stroke timer 14' whose set time T1 is variable is activated, and the output a of the stroke timer 14' is turned on, thereby turning on the relay. The output c of 15 is turned on, and the solenoid valve 16 is turned on. As a result, the control valve 6 is switched with a time delay τ ₁ , 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, thereby moving the weight 2 as shown in FIG. When the output a of the stroke timer 14' is turned off after the time determined by the set time _T1 , the control valve ₆ is pushed up as shown in e in FIG. Since the piston lower chamber returns to a position where it is communicated with the oil tank 8 and the piston upper chamber, the weight 2 falls and hits the pile 11 through the cap 10.

In this embodiment, when the pile 11 is hit, the proximity switch 19 (in this embodiment, the mounting position of the proximity switch 19 is such that the load of the hydraulic hammer 1 is applied to the pile 11 via the cap 10, and When the weight 2 is placed on the cap 10, the proximity switch 19 is placed in a position where it operates due to magnetic interaction with the lower end of the weight 2 made of magnetic material.Instead, when the weight 2 is in the pile striking position, the proximity switch 19 is disabled. (The installation position may be set so that it is activated and other positions are activated.)
The calculation unit 20 calculates the time T4 from when the output a of the switch 4' turns on until the output f of the proximity switch 19 falls at the first bounce during pile striking, and calculates the time T4 from the following equation (1). , interval timer 1
Calculate the time Tb to be set at 7'.

Tb=T4−T1−τ ₁ ...(1) Setting time of interval timer 14' in this equation
T1 and operation delay time τ ₁ are input to the calculation unit 20 from the interval timer 14' and the register 21, respectively. Since the interval timer 17' is initially set to a long setting time Ta, during the first striking operation, the output b' of the interval timer 17' is set from the time when the output of the relay 15 is turned off. It turns on, and turns off after this set time Ta. At the point when this output b' turns off, another timer starting relay 22 is activated to turn on the output h, and the stroke timer 14' is activated.
The relay 22 is reset by the output c of the relay 15.

The interval time from the second time onwards, that is, the time from when the output a of the stroke timer 14' is turned off to when it is turned on, is determined by the interval timer 1.
The set time Tb is newly set at 7',
Normally, the curve e representing the relative position of the weight with respect to the case 3 hardly changes unless the stroke changes or the soil quality changes significantly.
When activated for the set time Tb, as shown in A, the operation shifts to supplying pressure oil to the hydraulic cylinder 4 while the weight is bouncing and rising.

In this way, the time required for the weight 2 to hit the pile 11 once is measured, and the weight lifting operation is started when the measured time elapses after the weight lifting time starts. This eliminates wasted time and enables highly efficient pile driving work. For example, if the present invention is applied to a hydraulic hammer that conventionally could hit 20 times/min with a certain stroke, it becomes possible to hit around 25 times/min with the same stroke, increasing the number of hits by about 25%. This made it possible to significantly increase efficiency.

In addition, since the operation time for the weight 2 to hit the pile 11 is actually measured and the operation is controlled based on the measured time, it is possible to prevent the movement of the weight 2 from descending due to an error in the time setting of the interval timer, as in the past. There is no risk that the hydraulic circuit will be switched to the direction of pushing up the weight and that extremely high pressure will be generated in the hydraulic cylinder 4 and the like and damage these, improving operational safety.

Note that the time setting for the interval timer 17' may be done every time the pile is struck, but since the operating time will hardly change if the work is done with the same stroke, it is better to set it once every few or dozens of times. Alternatively, when changing the stroke, Ta may be set for a sufficiently long time first, and then the actual measurement time may be set.

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. FIG. 5 shows an example of this, in which a plurality of proximity switches 23a to 23d are provided at positions higher than the position where the pile 11 is struck by the weight 2 and have different heights.
The operator can select which proximity switch output to refer to by operating a selection switch group 24 consisting of switches corresponding to each proximity switch, and as shown in FIG. The relay 15' with the holding circuit is turned on, which turns on the solenoid valve 16 to switch the control valve 6, and the hydraulic cylinder 4
Pressure oil from the hydraulic source 5 is supplied to raise the weight 2, and the proximity switch (one of 23a to 23d) selected by the selection switch group 24 is activated to increase the output i. When it comes out, the relay 15' is turned off, thereby turning off the solenoid valve 16 and returning the control valve 6 to its original position, thereby causing the weight 2 to fall. On the other hand, when the output i is output, the interval timer 17' is started, and the output b' is turned off after an initially set time Ta, and when the output b' is turned off, the output h of the relay starting circuit 25 is turned on. This turns on the relay 15', and the relay starting circuit 25 is reset by the output of the relay 15'.

The calculation unit 20' does not measure the time from the start of the lifting movement of the weight 2 as in the above embodiment, but measures the time from the time when the output i is output, that is, the starting point of the movement for dropping the weight. The time T6 from the moment when the weight 2 bounces for the first time due to the impact of the pile 11 by the weight 2 until the output f of the proximity switch 19 is turned off is measured, and as shown in equation (2), ,
The set time Tb of the interval timer 17' is calculated by subtracting the operation delay time τ ₁ due to the hydraulic circuit etc. set in the register 21 from the time T6, and is set in the interval timer 17'.

Tb=T6−τ ₁ (2) After that, the set time Tb becomes the interval time, and the subsequent operation is as described above. In addition, the proximity switches 23a to 23d are connected to the stake 11 by the weight 2.
The circuit may be configured such that it is activated at the impact position of the weight 2 and deactivated when the weight 2 is raised.

According to this embodiment, as shown in FIG. 7, the stroke is changed to S1, S2,
It can be changed like S3 and S4.

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, the time when the weight 2 hits the pile 11 may be the time when the weight 2 starts hitting the pile 11 (the rise of the output f), or the like. In addition, as a means for detecting that the weight 2 hits the pile 11, not only a magnetic material sensitive type proximity switch but also an electrostatic type or a photosensitive type proximity switch can be used. Hammer 1
Detectors for vibration or vibration acceleration of surrounding equipment, detectors for impact sound, and stroke meters with potentiometers whose output changes depending on the height of the weight, etc., that can detect signals from impact, etc. If so, it can be used. 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. Further, the hydraulic hammer to which the present invention is applied may be of any type as long as the weight is raised by supplying pressure oil to the hydraulic cylinder and falls by removing the pressure oil. , a structure in which the weight also serves as a piston of a hydraulic cylinder may be used.

As described above, according to the present invention, the time from the starting point of the lifting operation of the electric circuit or hydraulic circuit for driving the weight or the time when the weight actually starts to rise until the time when the weight hits the pile; Alternatively, measure the time from the starting point of the falling movement of the electric circuit or hydraulic circuit for driving the weight, or from the time when the weight actually starts falling, to the time when the weight hits the pile, and adjust according to the length of the measured time. As a result, the suspension time of the lifting operation of the electric circuit or hydraulic circuit in the next cycle or thereafter is controlled to be long or short, so that regardless of the length of the stroke of the weight, the lifting of the weight after impacting the pile with the weight is controlled. It is possible to eliminate wasted time until the start of pile driving, and it is possible to perform pile driving work with significantly higher efficiency than before. 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]

FIGS. 1 and 2 are a block diagram and a time chart of a hydraulic hammer, respectively, explaining a conventional weight driving method, and FIGS. 3 and 4, respectively, illustrate an embodiment of the weight driving method of the present invention. A block diagram and a time chart of a hydraulic hammer, FIGS. 5 and 6 are respectively a block diagram and a time chart of a hydraulic hammer explaining another embodiment of the weight driving method of the present invention, and FIG. 7 is a diagram of a time chart of this embodiment. FIG. 3 is a waveform diagram illustrating the effect. 1... Hydraulic hammer, 2... Weight, 4... Hydraulic cylinder, 5... Control valve, 11... Pile, 1
3... Start switch, 14'... Stroke timer, 15, 15', 22, 25... Relay, 16
... Solenoid valve, 17' ... Interval timer, 19, 23a-23d ... Proximity switch, 2
0, 20'...Arithmetic unit, 21...Register, 24
...Selection switch group.

Claims (1)

[Scope of Claims] 1. The time from the starting point of the lifting operation of the electric circuit or hydraulic circuit for driving the weight, or from the time when the weight actually starts to rise, to the time when the weight hits the pile, and the actual measurement. 1. A method for driving a weight of a hydraulic hammer, characterized in that the suspension time of the lifting operation of the electric circuit or the hydraulic circuit in the next cycle or thereafter is controlled to be long or short in accordance with the length of the time. 2. Measure the time from the starting point of the falling movement of the electric circuit or hydraulic circuit for driving the weight, or from the time when the weight actually starts falling, to the time when the weight hits the pile, and calculate the time according to the length of the measured time. A method for driving a weight of a hydraulic hammer, characterized in that the duration of the lifting operation of the electric circuit or the hydraulic circuit is controlled to be long or short in the next cycle or thereafter.