JP4451051B2 - Impact speed variable impact tool - Google Patents

Description

BACKGROUND OF THE INVENTION
[0001]
The present invention relates to an impact moving tool such as a hydraulic breaker that is attached to a hydraulic excavator or the like and is used for dismantling of a concrete structure, rock crushing, rock excavation, or the like.
[0002]
[Prior art]
[0003]
In the impact moving tool, the number of hits per unit time, that is, the hitting speed, is changed according to the hardness of the rock to be crushed.
[0004]
A conventional impact moving tool of this kind is disclosed in Japanese Patent Laid-Open No. 4-93185.
[0005]
The impact tool includes a chisel that is slidable at the bottom of the cylinder and protrudes from the bottom of the cylinder, a piston that is slidable up and down in the cylinder, and a piston that is formed in the top of the cylinder and attaches the piston downward. A gas chamber to be energized, a direction switching valve for supplying pressure oil into the cylinder and moving the piston up and down in cooperation with the gas chamber, and a first pressure oil for connecting the direction switching valve to a first pressure oil supply source A supply line and gas chamber volume changing means for changing the volume of the gas chamber are provided, and the striking speed can be changed by a pressure change in the gas chamber accompanying a change in the volume of the gas chamber.
[0006]
Hereinafter, the gas chamber volume changing means will be described.
[0007]
The gas chamber volume changing means includes a working chamber formed above the gas chamber in the cylinder, and a body portion in which the upper flange is located in the working chamber and the lower flange is located in the gas chamber and connects both flanges. And a spool penetrating the partition wall separating the gas chambers, a spring for biasing the spool upward, and a second pressure supply line connecting the upper flange upper portion in the working chamber to the second pressure oil supply source.
[0008]
Further, the gas chamber volume changing means includes an operation start detecting means for outputting a supply start signal when the pressure oil supply from the first pressure oil supply source to the cylinder via the first pressure oil supply pipeline is started, and a supply signal And a timer device that outputs a switching signal when a preset time elapses.
[0009]
When the switching signal is output, pressure oil is supplied from the second pressure oil supply source above the upper flange in the working chamber, the spool moves downward, and the volume of the gas chamber decreases. When the volume decreases, the pressure in the gas chamber increases, and the ascending speed of the piston decreases and the striking speed decreases. By the way, when the pressure in the gas chamber increases, the force that urges the piston downward increases, so the force that the piston strikes the chisel increases. That is, the hitting force increases as the hitting speed decreases.
[0010]
As the volume of the gas chamber increases, the pressure in the gas chamber decreases, the piston ascending speed increases and the striking speed increases. By the way, when the pressure of the gas chamber is lowered, the force for urging the piston downward is weakened, so the force of the piston hitting the chisel is weakened.
[0011]
[Problems to be solved by the invention]
[0012]
In the conventional impact tool, it is necessary to form a working chamber for controlling the gas pressure above the gas chamber. This has the problem that the construction of the impact tool is complicated and large.
[0013]
Further, in the above-described impact moving tool, the relationship between the striking speed and the striking force is as follows. That is, the hitting force increases as the hitting speed decreases, and the hitting force decreases as the hitting speed increases.
[0014]
However, in practice, it is often preferable to work with a low striking force and a low striking force, or with a high striking speed and a large striking force.
[0015]
For example, in order to determine the hitting location of rocks, etc. and hit the hitting location accurately, hit the structure etc. with a slow hitting force with a low hitting force at the beginning of hitting, and make small cracks or scratches at the hitting location. After that, it is preferable to hit rocks or the like with a high hitting force and a high hitting force.
[0016]
The conventional impact moving tool cannot cope with such a case.
[0017]
Further, even if rocks or the like are crushed at the beginning of the hitting, it is difficult to stop the breaker at the same time as the crushing. In the case of the impact moving tool as described above, since the striking force is large when the striking speed is low, the damage to the impact moving tool due to the idling is increased at least.
[0018]
On the other hand, when the striking force is small, the striking speed is fast, so that the number of blank shots until the impacting tool is stopped increases, and the damage to the impacting tool is also increased.
[0019]
An object of the present invention is to solve the above-mentioned problems, and does not cause complication and enlargement of the configuration of the impact tool, and the impact speed is slow and a small impact force is required. It is an object of the present invention to provide an impact moving tool that can cope with a case where a quick and large impact force is required.
[0020]
It is another object of the present invention to provide an impact moving tool that is small in damage due to blanking when a structure or the like is crushed at the beginning of striking.
[0021]
By the way, there is an impact moving tool in which a pump that sends pressure oil to the impact moving tool is controlled by a pedal, and the amount of pressure oil to be sent to the impact moving tool is adjusted in proportion to the depression amount of the pedal.
[0022]
Although the crushing work is usually performed for a long time, the above-mentioned impact moving tool has a problem that the number of times the pedal depression amount is adjusted during the crushing work is considerably increased, which increases the burden on the operator.
[0023]
An object of the present invention is to solve the above-described problems, and to provide an impact moving tool with a small burden on an operator.
[0024]
[Means for Solving the Problems and Effects of the Invention]
[0025]
In order to solve the above problems, the impact tool of the present invention is:
[0026]
An operation start detecting means for detecting an operation start of the tool body in an impact movement tool provided in the middle of the flow path connecting the pump and the tool body pressure oil supply port, the breaker drive valve for operating the impact tool body,
A timer device that counts a predetermined time after the start of operation, and a pressure oil supply amount adjusting means that increases the amount of pressure oil supplied to the impact tool per unit time after the predetermined time has elapsed,
The pressure oil supply amount adjusting means includes a two-position solenoid valve connected to the pilot port of the breaker control valve, and a pressure reducing valve provided in the middle of the flow path connecting the solenoid valve and the on / off valve connected to the control pump. A drive valve control device provided to the breaker drive valve,
The time set by the timer after the start of operation is such that the control pressure oil supplied from the control pump is applied to the pilot port of the breaker drive valve from the two-position solenoid valve via the pressure reducing valve, and the spool displacement of the drive valve Limit
When the timer expires after the lapse of a predetermined time, the entire amount of control pressure oil is directly applied from the two-position solenoid valve to the breaker drive valve to displace the entire spool of the drive valve,
The breaker drive valve employs a configuration in which a limited amount of pressure oil or a total amount of pressure oil is supplied from the pump to the tool body according to the amount of displacement of the spool .
[0027]
Since this impact moving tool changes the striking speed by increasing or decreasing the amount of hydraulic oil supplied to the impact moving tool body per unit time, it is not necessary to provide a working chamber above the gas chamber, and the impact moving tool The configuration is not complicated and large.
[0028]
Further, when the amount of pressure oil supplied per unit time to the impact tool body is reduced, the impact speed is reduced and the impact force is also reduced. When the amount of pressure oil supplied per unit time increases, the impact speed increases and the impact force also increases.
[0029]
Therefore, if a predetermined time is set in the timer device, until the predetermined time elapses, that is, at the beginning of the hitting, the work is performed with a low hitting force with a low hitting force. Work quickly and with great striking force. For this reason, the damage of the impacting tool due to the blanking which is performed when the rock or the like is crushed at the initial stage of hitting is reduced.
[0030]
In addition, with this impact moving tool, it is not necessary to adjust the amount of pedal depression during work, and the burden on the operator is not increased.
[0031]
In the impact tool,
[0032]
The timer device has a timer body for counting time and a time storage means for storing a predetermined time. The timer body starts counting when the start of operation is detected, and is stored in the time storage means after the start of counting. When the predetermined time has elapsed, the count is stopped, and the pressure oil supply amount adjusting means increases the amount of pressure oil supplied to the impact tool body per unit time when the timer device stops counting. .
[0033]
Further, the operation start detection means may be a pressure switch.
[0034]
Further, the pressure oil supply amount adjusting means is provided in a flow path for supplying pressure oil to the impact tool body, and controls the drive valve for adjusting the amount of pressure oil supplied to the impact tool body, and the drive valve. It may be composed of a drive valve control device.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
[0036]
Hereinafter, with reference to FIGS. 1-3, the striking speed variable hydraulic breaker of one Embodiment of this invention is demonstrated. The hydraulic breaker body 1 is used by being attached to a hydraulic excavator. The hydraulic breaker body 1 is provided with a cylinder, a chisel provided at the lower portion of the cylinder so as to protrude downward and slidable, and slidable up and down within the cylinder. And a gas chamber that is formed in the upper part of the cylinder and urges the piston downward, and a direction switching valve that supplies pressurized oil into the cylinder and moves the piston up and down in cooperation with the gas chamber. ing. In addition, since each part structure of the hydraulic breaker main body 1 is well-known, description is abbreviate | omitted and the structure for making an impact speed variable is demonstrated below.
[0037]
The hydraulic breaker body 1 is formed with a pressure oil supply port P1 and a pressure oil discharge port P2, a tank 4 is connected to the pressure oil discharge port P2, and a breaker drive valve 2 is connected to the pressure oil supply port P1. It is connected. The breaker drive valve 2 is also connected to the breaker drive pump 3, and the pressure oil delivered from the breaker drive pump 3 is supplied to the hydraulic breaker body 1 through the breaker drive valve 2.
[0038]
The breaker drive valve 2 adjusts the amount of pressure oil supplied from the breaker drive pump 3 to the hydraulic breaker body 1 by the stroke of a spool (not shown) provided therein, and has a known configuration. ing. 1-3, the breaker drive valve 2 is represented as a three-position valve for convenience.
[0039]
FIG. 1 shows a state in which the spool is not stroked. In this state, all the pressure oil from the breaker drive pump 3 is returned to the tank 4. FIG. 3 shows a state in which the spool is fully stroked. In this state, all the pressure oil is supplied to the hydraulic breaker body 1. FIG. 2 shows a state where the spool has made a slight stroke. In this state, a part of the pressurized oil is returned to the tank 4 through the throttle 2a, and the remaining pressurized oil is supplied to the hydraulic breaker body 1. .
[0040]
The spool stroke is adjusted by changing the pilot pressure of the pilot port CP2 of the breaker drive valve 2. Hereinafter, a configuration for changing the pilot pressure of the pilot port CP2 will be described.
[0041]
The pilot port CP <b> 2 is connected to the drive valve control device 6, and the drive valve control device 6 is connected to the control pump 11 via the on / off valve 10. The on / off valve 10 is controlled by a pedal 5 provided in the operation chamber of the hydraulic excavator. When the pedal 5 is depressed, pressure oil is supplied from the control pump 11 to the drive valve control device 6.
[0042]
The drive valve control device 6 includes a two-position electromagnetic valve 6a and a pressure reducing valve 6b connected to the pilot port CP2. As shown in FIG. 2, when the electromagnetic valve 6a is in the right position, the pilot port CP2 When the electromagnetic valve 6a is in the left position as shown in FIGS. 1 and 3, the pilot port CP2 is connected to the on / off valve 10 via the pressure reducing valve 6b. It is directly connected to the on / off valve 10 without going through.
[0043]
Note that by adjusting the pressure reducing valve 6b, the pressure of the pressure oil supplied to the pilot port CP2 can be changed, the stroke amount of the spool of the breaker drive valve 2 can be adjusted, and the amount of oil supplied to the hydraulic breaker body 1 can be changed. it can.
[0044]
That is, the solenoid valve 6a supplies the pressure oil decompressed by the decompression valve 6b or the pressure oil not directly decompressed directly supplied from the on / off valve 10 to the pilot port CP2 of the breaker drive valve 2. . The pressure oil supplied to the pilot port CP2 is switched by a signal input to the control terminal CT6 of the solenoid valve 6. The control terminal CT6 is connected to the timer device 7.
[0045]
The timer device 7 includes a timer body 7a and a switching time storage device (time storage means) 7b that stores a predetermined time (timing for switching the hitting speed).
[0046]
The timer body 7a outputs an ON signal when counting is performed, and does not output a signal when counting is not performed. This signal is input to the control terminal CT6 of the electromagnetic valve 6a. When the ON signal is input to the control terminal CT6, the electromagnetic valve 6a is in the right position as shown in FIG. 2, and the pressure oil that has passed through the pressure reducing valve 6b is supplied to the pilot port CP2 of the breaker drive valve 2. If no signal is input to the control terminal CT6, the electromagnetic valve 6a is in the left position as shown in FIG. 3, and the pressure oil not passing through the pressure reducing valve 6b is supplied to the pilot port CP2 of the breaker drive valve 2.
[0047]
Note that the switching time storage device 7b is provided in the operation chamber of the hydraulic excavator, and the storage time can be freely set in the operation chamber.
[0048]
Furthermore, a pressure switch 8 for detecting the pressure in the flow path connecting the on / off valve 10 and the drive valve control device 6 is provided. The pressure switch 8 is turned on when pressure oil flows in the flow path and the pressure in the flow path increases. The pressure switch 8 is connected to the timer device 7, and the timer body 7a starts counting when the pressure switch 8 is switched from OFF to ON.
[0049]
The hydraulic breaker having the above configuration operates as follows.
[0050]
As shown in FIG. 1, when the pedal 5 is not operated and no pressure oil is sent from the control pump 11 to the control device 6, no pressure oil is supplied to the pilot port CP <b> 2 of the breaker drive valve 2. . In this state, all of the pressure oil sent from the breaker drive pump 3 is returned to the tank 4 and the hydraulic breaker body 1 is not operating.
[0051]
In this state, since the pressure oil is not sent from the control pump 11 to the control device 6, the pressure switch is OFF. Further, since the timer device 7 is not counting and no signal is input to the control device 6, the electromagnetic valve 6a is in the left position.
[0052]
In this state, the storage device stores a predetermined time, that is, a time for operating the hydraulic breaker at a slow hitting speed. Further, the pressure for depressurization is determined by adjusting the pressure reducing valve 6b, and the slow hitting speed is determined.
[0053]
Next, as shown in FIG. 2, the pedal 5 is depressed to operate the on / off valve 10, and pressure oil is supplied to the control device 6. Then, the pressure in the flow path connecting the on / off valve 10 and the drive valve control device 6 rises, and the pressure switch 8 is switched from OFF to ON. By this switching, the timer device 7 is turned on and counting is started. And the ON signal from the timer apparatus 7 is input into control terminal CT6 of the control apparatus 6, and the solenoid valve 6a switches to the right position. For this reason, the pressure oil decompressed through the pressure reducing valve 6 b is supplied to the breaker drive valve 2. Then, the spool of the breaker drive valve 2 slightly moves, and a part of the pressure oil sent from the breaker drive pump 3 is returned to the tank 4 through the throttle 2a, and the rest is supplied to the breaker body 1. Become. When the pressure oil is supplied to the breaker body 1, the breaker body 1a starts operating.
[0054]
On the other hand, the timer device 7 compares the counted value with the value stored in the storage device 7b while counting. When the stored value matches the counted value, the timer device 7 stops and no signal is input to the control terminal CT6 of the control device 6.
[0055]
When newcomer Cormorant to the control terminal CT6 is not input, as shown in FIG. 3, the electromagnetic valve 6a is switched to the left position. For this reason, the pressure oil is directly supplied from the electromagnetic valve 6a to the breaker drive valve 2, and the drive valve 2 is completely switched to the right position. Then, all the pressure oil sent from the breaker drive pump 3 is supplied to the breaker body 1. In this way, since the amount of pressure oil supplied increases, the breaker body 1 operates at a higher hitting speed and higher hitting force than before.
[0056]
As described above, the hydraulic breaker according to the present invention operates with a low striking speed and a small striking force at the beginning of striking, and with a high striking speed and a large striking force after a predetermined time has elapsed.
[0057]
In the above-described embodiment, the pressure at which the pressure is reduced by the pressure reducing valve is set in advance before the operation of the breaker, and the striking speed at the beginning of the impact is determined. It may be. If it does so, the pressure which can be pressure-reduced even during the operation | movement of a breaker can be adjusted freely, and a striking speed can be set arbitrarily.
[0058]
[Brief description of the drawings]
FIG. 1 is a diagram showing a hydraulic circuit in a stopped state of a hydraulic breaker according to an embodiment of the present invention.
FIG. 2 is a diagram showing a hydraulic circuit in an initial state of hitting of the hydraulic breaker.
FIG. 3 is a diagram showing a hydraulic circuit after a predetermined time has elapsed in the hydraulic breaker.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Breaker body 2 Drive valve 6 Drive valve control device 7 Timer device 7a Timer body 7b Time storage means 8 Pressure switch (operation start detection means)

Claims (2)

In the impact tool provided in the middle of the flow path connecting the pump and the tool body pressure oil supply port, the breaker drive valve that operates the impact tool body
An operation start detecting means for detecting the operation start of the tool body;
A timer device that counts a predetermined time after the start of operation, and a pressure oil supply amount adjusting means that increases the amount of pressure oil supplied to the impact tool per unit time after the predetermined time has elapsed,
The pressure oil supply amount adjusting means includes a two-position solenoid valve connected to the pilot port of the breaker control valve, and a pressure reducing valve provided in the middle of the flow path connecting the solenoid valve and the on / off valve connected to the control pump. A drive valve control device provided to the breaker drive valve,
The time set by the timer after the start of operation is such that the control pressure oil supplied from the control pump is applied to the pilot port of the breaker drive valve from the two-position solenoid valve via the pressure reducing valve, and the spool displacement of the drive valve Limit
When the timer expires after the lapse of a predetermined time, the entire amount of control pressure oil is directly applied from the two-position solenoid valve to the breaker drive valve to displace the entire spool of the drive valve,
The breaker drive valve is an impact moving tool configured to supply a limited amount or a total amount of pressure oil according to the amount of displacement of the spool from the pump to the tool body. The operation start detection means is a pressure switch, and the timer device has a timer main body for counting time and a time storage means for storing a predetermined time. The timer main body counts when the operation start of the tool main body is detected. After the count starts, the count is stopped when a predetermined time stored in the time storage means has elapsed,
The impact moving tool according to claim 1, wherein the pressure oil supply amount adjusting means increases the amount of the pressure oil supplied to the impact moving tool per unit time when the timer device stops counting.

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