JPS5837568Y2 - striking device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a striking device equipped with a piston-type hammer that applies impact energy to a working tool such as a chisel through reciprocating motion.

Generally, when using a striking device such as a rock drill or a breaker, as shown in FIG. The hammer 83 hits the head of the working tool 80 to impact the object 81 to be crushed.

However, as shown in FIG. 1B, if the object to be crushed is soft and the working tool 80 digs into the object 81 by a considerable amount with one impact, the hammer 83 will be pushed into the working tool 81.
A so-called dry striking phenomenon occurs in which the head of the hammer cannot be struck, and the piston part 84 of the hammer gets stuck in the cylinder end part 85 and then stops abruptly, resulting in a large impact force being applied to each part of the striking device such as the cylinder, resulting in damage. may occur.

In addition to the above, if the working tool gets caught in the object to be crushed and cannot be removed while the impact device is in use, the impact device can be used to perform dry striking in order to efficiently pull out the working tool from the object to be crushed. The striking device may be pulled up while applying vibrations to the striking device, and there is a risk that the striking device may be damaged due to such dry striking that is unavoidable during work.

This invention solves the above-mentioned conventional drawbacks. By using hydraulic pressure to decelerate the hammer that descends beyond the normal working tool striking position, the striking device can be damaged even during dry striking when the hammer does not strike the working tool. The object of the present invention is to provide a striking device that does not cause the occurrence of.

An embodiment of this invention will be explained below with reference to FIG.

In the figure, 1 is a housing, and a hammer 3 is housed inside a cylinder 2 provided in the housing so as to be slidable in the vertical direction.

4 is an upper piston of the hammer, 5 is a lower piston, 6 is an upper small diameter part of the hammer, 7 is a middle small diameter part, and 8 is a lower small diameter part.

The diameter of the lower small diameter portion 8 is smaller than that of the upper small diameter portion 6, and therefore the area of the upward pressure receiving surface 9 of the lower piston is larger than the area of the downward pressure receiving surface 10 of the upper piston.

The inner wall surface of the cylinder 2 and each piston part of the hammer 3 create an upper chamber 11 and a lower chamber 1 with variable volume inside the cylinder 2.
2, and a middle chamber 13 whose volume remains unchanged.

A buffer chamber 14 is provided below the lower chamber 12 and is continuous with the lower chamber, and is composed of a narrow diameter portion 14a and an annular groove portion 14b, and the inner diameter of the narrow diameter portion 14a is slightly smaller than the outer diameter of the lower piston 5. The quantity is large.

Reference numeral 20 denotes a switching valve for controlling the reciprocating motion of the hammer 3, and its spool 21 is housed in a housing 22 so as to be slidable in the vertical direction.

23 is an annular groove for switching the hammer drive circuit provided on the spool, 24 is an upper small diameter part of the spool, and 25 is a lower small diameter part smaller in diameter than the upper small diameter part, so the area of the upper pressure receiving surface 26 of the spool is is larger than the area of the lower pressure receiving surface 27.

An upper pilot chamber 28 and a lower pilot chamber 29 are formed by these pressure receiving surfaces and holes provided in the housing 22 into which the small diameter portions fit.

On the other hand, 30 is a high-pressure pipeline for supplying pressure oil, and has an annular inlet chamber 32 provided in a valve hole 31 into which the large diameter portion of the spool 21 fits.
, the lower pilot chamber 29, and the upper chamber 11 of the cylinder.
, and its population 33 is connected to an external pressure source 34, such as a hydraulic bump.

Reference numeral 35 denotes a low-pressure pipe line for return oil, including an annular low-pressure chamber 36 provided in the cylinder and an annular outlet chamber 37 provided in the valve hole.
The outlet 38 is connected to a tank 39.

Reference numeral 40 denotes a supply/discharge pipe line communicating with the lower chamber 12 of the cylinder and an annular supply/discharge chamber 41 provided in the valve hole.

42 is an annular pilot chamber 43 provided in the cylinder 2.
A pipe line 44 communicates between the pilot chamber 43 and the buffer chamber 14 .

Note that 45 is an accumulator installed at a suitable location in the high-pressure pipe 30, 46 is a low-pressure chamber communicating with the atmosphere or the tank 39,
47 is inserted into the housing 1 so that it can move up and down,
48 is a stopper for removing it.

In the above configuration, the housings 1 and 22 are divided as appropriate so that they can be fixed to each other so as to accommodate the hammer, spool 21, and the like.

Next, the operation of the striking device having the above structure will be explained.

Figure 1 shows the hammer 3 in the working tool striking position and the chisel 4.
7 is hit normally, and the high oil pressure P from the high pressure pipe 30 is acting on the descending pressure receiving surface 10 of the hammer.

On the other hand, the annular groove portion 23 of the spool of the switching valve 20 is connected to the outlet chamber 3.
7 and the supply/discharge chamber 41, a low oil pressure P approximately equal to O of the low pressure pipe 35 is applied to the lifting pressure receiving surface 9 of the hammer.

is working.

Since the pilot chamber 43 opens to the high-pressure upper chamber 11 at the illustrated position of the hammer 3, high-pressure oil flows into the buffer chamber 14 through the pipe 44, and pressure P acts on the upper pressure-receiving surface 26 of the spool 21. The spool 21 is driven downward (in the direction of the arrow
1 and the inlet chamber 32, pressure P acts on the lifting pressure receiving surface 9 of the hammer 3, and the area of the lifting pressure receiving surface 9 is:
Since the area is larger than the area of the descending pressure receiving surface 10, the hammer 3 rises by overcoming the pressing blade due to the pressure P acting on the descending pressure receiving surface 10.

As the hammer 3 rises, the pilot chamber 43 is blocked by the upper piston 4, and then the low pressure chamber 36 opens to the middle chamber 13, and when the hammer 3 reaches almost the upper reversal position, the pilot chamber 43 opens to the middle chamber 13, and the low pressure chamber 36 opens to the middle chamber 13. The chamber 36 communicates with the low pressure pipe line 35.

This causes the buffer chamber 14 to communicate with the low pressure line 35, while the upper pilot chamber 28 of the switching valve communicates with the line 42.
The spool 21 is driven upward, and the annular groove 23 connects the supply/discharge chamber 41 and the outlet chamber 37. When this happens, the lower chamber 12 communicates with the low pressure line 35 via the supply and discharge line 40, and the pressure acting on the lifting pressure surface 9 of the hammer is P.

As a result, the hammer 3 is driven downward by the pressure P acting on the descending pressure receiving surface 10, and the above-mentioned movement is repeated thereafter.

Next, the idle striking operation of the hammer 3 will be explained.

In the state where the chisel 47 has moved downward as shown by the chain line 50 in FIG. The piston 5 enters the buffer chamber 14 as indicated by a chain line 51 beyond the lower chamber 12, which is still at a low pressure before the switching operation of the switching valve 20 is completed.

As described above, this buffer chamber 14 communicates with the high-pressure pipe 30 via the pipe 44, the pilot chamber 43, and the upper chamber 11, so that the high hydraulic pressure P acts on the lifting pressure receiving surface 9 of the hammer. 3 decelerates at an appropriate deceleration and reverses upwards.

The transient shock pressure generated at this time is absorbed by the accumulator 45.
absorbed by.

As the hammer 3 rises, the pilot chamber 43 is closed by the upper piston 4, but at this time, the pressure in the lower chamber 12 is reduced to P by the switching valve 20, which has already completed its switching operation.
Therefore, hammer 3 continues to rise.

The reversing operation of the hammer 3 at the upper reversing position is the same as that during the above-mentioned normal striking, and subsequent blank strikes can be repeated in the same manner.

In the above embodiment, instead of directly connecting the buffer chamber 14 to the pilot chamber 43 through the pipe 44, the buffer chamber 14
Similar effects can be obtained by connecting the pipe 42 or the upper pilot chamber 28 to the pilot chamber 43 indirectly.

Further, in the above embodiment, the pilot chamber 43 is connected to the switching valve 20.
Although the pilot chamber for operation and the pilot chamber for pressure switching of the buffer chamber 14 are used, they may be provided separately. For example, in FIG.
2 may be connected, a pilot chamber 43a may be provided near the pilot chamber 43, and the conduit 44 may be connected to this.

In this case, depending on the position of the pilot chamber 43H, the pilot chamber 43
・A may remain closed by the upper piston 4, but if the lower chamber 12 is switched to low pressure by the switching valve 20, the pressure in the buffer chamber 14 integrated with the lower chamber 12 will also be low, so the hammer 3 Inversion and descent are performed without any problem.

FIG. 3 shows another embodiment of this invention, in which the buffer chamber 60 is formed into a cylindrical shape having an inner diameter that is appropriately larger than the outer diameter of the lower piston 5, and a positive gap is formed between the inner wall of the buffer chamber and the outer periphery of the lower piston. The only difference from the embodiment shown in FIG. 2 is that a gap 61 is provided between the two.

In this embodiment, the pressure oil in the buffer chamber 60 after the lower piston 5 enters the gap 61. The oil flows out into the low-pressure pipe 35 through the lower chamber 12, the supply/discharge pipe 40, and the annular groove 23 of the switching valve before switching is completed, and depending on the amount of oil flowing out, the pressure P is initially applied to the pressure receiving surface 9 for lifting the piston. A somewhat lower pressure is applied, and as the spool 21 moves downward, the amount of oil flowing out decreases, so the pressure within the buffer chamber 60 increases and finally reaches the pressure P.

Therefore, the deceleration force of the hammer 3 increases in accordance with the amount of downward movement of the hammer, and smooth deceleration can be achieved, and less impact pressure is generated, so the accumulator 45 is not necessary.

However, it is necessary to make the axial length of the buffer chamber 60 slightly larger.

Note that instead of providing the gap 61, in the embodiment shown in FIG. 2, a thin conduit connecting the lower chamber 12 and the annular groove 14b may be provided, and if a variable throttle valve is provided in the middle of this conduit, the airflow can be reduced. The deceleration of the hammer during striking can be adjusted.

FIG. 4 shows still another embodiment of this invention, in which parts given the same reference numerals as in FIG. 1 indicate the same or equivalent parts as in FIG. 1.

In the figure, 70 is a gas chamber into which the upper small diameter portion 6 of the hammer 3 is fitted, and is filled with compressed air or an inert gas such as pressurized nitrogen.

The low pressure chamber 36 is provided outside the upper chamber 11 to maintain the upper chamber 11 at a low pressure at all times, and an annular groove 71 communicating with the high pressure pipe 30 is provided below the pilot chamber 43.

Further, the upper pilot chamber 28 of the switching valve is communicated with the annular groove portion 14b of the buffer chamber through a short pipe line 72.

The descending pressure receiving surface 10 is the upper end surface of the upper small diameter portion 6.

That is, in this embodiment, the hammer is lowered by the compressed gas pressure in the gas chamber 70 that constantly acts on the lowering pressure receiving surface 10 of the hammer, and the hydraulic pressure P is applied to the ascending pressure receiving surface 9 by switching the switching valve 20. The hammer 3 is reversed and raised by overcoming the push-down blade by compressed gas pressure, and although a detailed explanation will be omitted, the same effects as the embodiment shown in FIG. 2 can be obtained.

As shown in the figure, switching to the high oil pressure in the pilot chamber 43 is achieved by the passage of the annular groove 71 by the lower piston 5 into the middle chamber 13.
This is done by opening the pilot room 4.
3 to switch to low oil pressure, the hammer 3 rises and the low pressure chamber 36
This is done by opening into the middle chamber 13 through the passage of the upper piston 4.

In this embodiment, the upper pilot chamber 28 of the switching valve and the annular groove 14b of the buffer chamber are directly communicated with each other through a short pipe 72, so that the lower piston 5 enters the buffer chamber 14 during dry firing, causing transient Since the high pressure, which is higher than the pressure p generated in the
Furthermore, this movement of the spool 21 has the effect of preventing the above-mentioned abnormal rise in high pressure.

Furthermore, in this embodiment, the oil discharged from the lower chamber 12 when the hammer ascends flows into the upper chamber 11 whose volume increases as the hammer descends, so there is no pipe resistance due to the oil flow out of the housing. The back pressure inside the chamber 12 is low, and the hammer 3 can be lowered at high speed to perform efficient striking.

In each of the above embodiments, in addition to fluid pressure such as oil pressure or gas pressure, elastic force such as a compression spring may be used as the drive source for urging the hammer downward, or several types of drive sources may be used in combination. You can.

Furthermore, the switching valve 20 may have a structure other than that described above.

In addition, the pilot chamber 43 starts communicating with the high-pressure pipe immediately before the descending hammer reaches the working tool striking position as shown in each of the above embodiments, and also immediately after the lower piston 5 enters the buffer chamber 14 at the latest. It is sufficient as long as it starts communicating with the high-pressure pipeline by then.

Although the above description has been made regarding the case where this invention is applied to a breaker, this invention can also be applied to other striking devices such as a rock drill.

As explained above, according to this invention, a buffer chamber into which the piston of the hammer that descends beyond the normal working tool striking position is fitted is provided, and this buffer chamber is communicated with the high pressure pipe to slow down the hammer. As a result, the hammer decelerates and reverses due to the liquid pressure, or after sufficiently decelerating, it contacts the end of the cylinder at a low speed, so there is no damage to the striking device due to dry striking, and the striking device continues to operate normally. Both the working tool striking and dry striking can be performed freely, and the crushing of soft ground and the pulling out of the working tool by continuous dry striking can be carried out without any trouble, and the work efficiency can be improved.

[Brief explanation of the drawing]

1A and 1B are vertical cross-sectional views of main parts of a conventional striking device, FIG. 2 is a vertical sectional view of a striking device showing an embodiment of this invention, and FIG.
This figure is a vertical cross-sectional view of the main part of a striking device showing another embodiment of this invention, and FIG. 4 is a view corresponding to FIG. 2 showing still another embodiment of this invention. 2...Cylinder, 3...Hammer, 5.
...Lower piston, 9...Pressure receiving surface for ascending, 10...Pressure receiving surface for descending, 12...Lower chamber, 14...Buffer Room, 14a...
Narrow diameter part, 14b... Annular groove part, 20...
・Switching valve, 30...High pressure pipe, 34...
・Pressure supply source, 35...Low pressure pipe line, 43...
... Pilot room, 43 a ... Pilot room, 44 ... Pipeline, 47 ... Hoop.
60...Buffer chamber, 61...Gap, 7
0... Gas chamber.

Claims (1)

[Scope of utility model registration request] A hammer, which is provided with a piston part that is arranged vertically reciprocatingly in a cylinder and has a pressure-receiving surface for upward movement, is moved downward by fluid pressure and/or elastic force so as to strike an operating tool such as a chisel during downward movement. At the same time, the lower chamber formed by dividing the cylinder by the rising pressure receiving surface is alternately divided into a high-pressure pipe and a low-pressure pipe by the switching operation of a switching valve that is driven by hydraulic pressure in relation to the position of the hammer. In the striking device, a buffer chamber into which the piston portion of the hammer fits is provided below the lower chamber and communicates with the lower chamber, and the hammer is moved up and down while the hammer is being lowered. A striking device characterized in that a pilot chamber, which communicates with a high-pressure pipeline when the tool reaches a substantially working tool striking position, is connected to the buffer chamber by a pipeline.