JP4813326B2 - Gas pressure detection mechanism - Google Patents

Description

  The present invention relates to a gas pressure detecting mechanism for inspecting a gas pressure in a back head gas chamber of a breaker.

In recent years, many breakers for crushing rocks and the like perform a striking stroke of a striking piston using gas pressure or gas pressure and hydraulic pressure (see Patent Document 1). An example of such a breaker is shown in FIG.
The breaker 1 includes a breaker body 2 and a bracket (not shown). The breaker body 2 is supported by the bracket, and the bracket is attached to the arm of the work machine.

The breaker body 2 includes a chisel 3, a front head 4, a cylinder 5, a back head 6, and a striking piston 10. The chisel 3 is mounted on the front head 4, and a striking piston 10 that strikes the chisel 3 is built in the cylinder 5. The back head 6 is connected to the rear end of the cylinder 5.
The back head 6 is provided with a back head gas chamber 8 filled with an inert gas, and the rear end portion of the striking piston 10 enters and exits the back head gas chamber 8. The inert gas in the back head gas chamber 8 is compressed in the backward stroke of the striking piston 10, and the compressed inert gas is applied to the striking piston 10 in the forward travel of the striking piston 10 (that is, the striking stroke in which the chisel 3 is struck). Apply forward force.

The back head gas chamber 8 has an air supply hole 9 through which an inert gas is supplied, and an air supply valve 46 is screwed into the air supply hole 9 with an attachment screw.
Some leakage of the inert gas from the back head gas chamber 8 is inevitable, and the gas pressure in the back head gas chamber 8 decreases with time, and the striking force of the striking piston 10 decreases. Therefore, it is important to maintain and manage the gas pressure in the back head gas chamber 8 within the allowable range of use. The gas pressure in the back head gas chamber 8 is regularly inspected, and the back head gas chamber 8 is inadequate if necessary. Refill with active gas.

The gas pressure in the back head gas chamber 8 is inspected by attaching a pressure detection device 11 such as a Bourdon tube pressure detector to the air supply valve 46.
Refilling the back head gas chamber 8 with the inert gas is performed by connecting the inert gas cylinder 13 to the air supply valve 46 via the regulator 12 and adjusting the secondary pressure of the inert gas with the regulator 12. After the inert gas is replenished to the back head gas chamber 8, the pressure detection device 11 is attached to the air supply valve 46 and the gas pressure in the back head gas chamber 8 is confirmed.
JP-A-4-300192

  However, the pressure detection device 11 such as a Bourdon tube pressure detector is a precision device and is easily damaged. In addition, when the pressure detection device 11 is attached to and detached from the air supply valve 46, the inert gas easily leaks from the back head gas chamber 8, and an unskilled person such as a field worker inspects the gas pressure in the back head gas chamber 8. When it is repeated, the gas pressure in the back head gas chamber 8 tends to decrease in a short period of time. In particular, when the capacity of the back head gas chamber 8 is small, the influence of the leakage of the inert gas generated when the pressure detection device 11 is attached to and detached from the supply valve 46 is large.

Further, when the back head gas chamber 8 is replenished with the inert gas, the adjustment work of the regulator 12 is complicated.
For this reason, it is difficult for a field worker to maintain and manage the gas pressure in the back head gas chamber 8, and a serviceman is called to check the gas pressure in the back head gas chamber 8 and to supply inert gas to the back head gas chamber 8. Replenishment is performed.
The present invention solves the above-described problems, and provides a gas pressure detection mechanism that enables a field worker to easily maintain and manage the gas pressure in the back head gas chamber of a breaker at a work site.

The present invention adopts the following configuration in order to solve the problem. A gas pressure detection mechanism according to a first aspect of the present invention includes a body having a pressure detection gas chamber communicating with a back head gas chamber of a breaker, and one end thereof slidably fitted into the pressure detection gas chamber, and gas pressure in the pressure detection gas chamber. A spool configured to protrude outside the body; and a spring that applies an urging force against the gas pressure in the pressure detection gas chamber to the spool.

According to the first invention, the gas pressure of the back head gas chamber of the breaker is transmitted to the pressure detection gas chamber of the gas pressure detection mechanism, the gas pressure of the pressure detection gas chamber acts on the spool, the spool is pushed by the gas pressure, and the spool One end protrudes outside the body. The amount of protrusion of the spool is determined by the difference between the biasing force acting from the spring and the gas pressure of the pressure detection gas chamber. If the gas pressure in the pressure detection gas chamber is high, the amount of protrusion of the spool increases, and the gas pressure in the pressure detection gas chamber If it is low, the amount of protrusion of the spool becomes small. Therefore, it can be easily determined whether or not the gas pressure in the back head gas chamber is within the allowable use range by looking at the protruding amount of the spool.
It is not necessary to attach or detach the pressure detection device every time the pressure is detected, and the gas pressure in the back head gas chamber is not reduced by the pressure detection.

A gas pressure detection mechanism according to a second invention is the gas pressure detection mechanism according to the first invention , wherein an air supply valve connected to the pressure detection gas chamber, a needle valve for adjusting the gas pressure of the pressure detection gas chamber, .
According to the second invention, gas can be replenished from the air supply valve to the back head gas chamber via the pressure detection gas chamber of the gas pressure detection mechanism. When the gas pressure in the back head gas chamber exceeds the allowable use range, the gas can be exhausted from the needle valve, and the gas pressure in the back head gas chamber can be adjusted to the allowable use range. Since the gas discharge flow rate can be finely adjusted by the needle valve, the gas pressure can be easily adjusted.
If necessary, a pressure detection device such as a Bourdon tube pressure detector can be attached to the air supply valve to detect the gas pressure in the back head gas chamber.

A gas pressure detection mechanism according to a third aspect of the present invention is the gas pressure detection mechanism according to the first or second aspect of the present invention, and includes a cap that pushes a spool protruding outside the body into the body.
According to the third invention, during operation of the breaker, the spool can be pushed into the body by the cap and the tip of the spool can be held by the cap. By holding the tip of the spool with a cap, even if the striking piston reciprocates during operation of the breaker and the gas pressure in the back head gas chamber fluctuates, the spool does not move and the spring that biases the spool Expansion and contraction with pressure fluctuation is prevented. As a result, wear of a seal such as an O-ring attached to the spool and wear of a sliding portion between the spool and the body are reduced, and fatigue of the spring is prevented. In addition, the cap can prevent the spool from being exposed to the outside, and the end of the spool can be prevented from being worn or damaged by dust generated during operation of the breaker.

  Since the gas pressure detection mechanism according to the present invention has the above-described configuration, an on-site worker can easily maintain and manage the gas pressure in the back head gas chamber of the breaker at the work site.

The best mode for carrying out the present invention will be described with reference to FIGS.
The breaker body 2 of the breaker shown in FIGS. 1 and 2 has the same configuration as the above-described conventional one, and includes a cylinder 5, a back head 6 connected to the rear end of the cylinder 5, and a striking piston built in the cylinder 5. 10 is provided. The back head 6 has a back head gas chamber 8 filled with an inert gas, and the rear end portion of the striking piston 10 enters and exits the back head gas chamber 8. The back head gas chamber 8 has an air supply hole 9, and the air supply hole 9 opens on the upper surface 7 of the back head 6.

A gas pressure detection mechanism 20 shown in FIGS. 1 to 4 is mounted on the upper surface 7 of the back head 6. The gas detection pressure mechanism 20 includes a body 22, a spool 38, an air supply valve 46, a needle valve 48, and a cap 50.
The body 22 is a block body bolted to the upper surface 7 of the back head 6, and a columnar protrusion 26 is formed on the front surface 24 </ b> F of the body 22. The through hole 30 penetrates from the front end surface 28 of the cylindrical protrusion 26 to the rear surface 24R of the body 22. The through-hole 30 is formed by a small-diameter hole 32, a medium-diameter hole 34, and a large-diameter hole 36 that are arranged in order from the cylindrical protrusion 26 side.

  The spool 38 has a small diameter portion 40 and a large diameter portion 42 on the rear end side of the small diameter portion 40. The small-diameter portion 40 is inserted into the small-diameter hole 32 and the medium-diameter hole 34, the large-diameter portion 42 is slid into the large-diameter hole 36, and an O-ring 68 a attached to the large-diameter portion 42 is connected to the large-diameter portion 42. The space between the large-diameter holes 36 is sealed. A step groove 44 is formed as a scale at the tip portion of the small diameter portion 40, and the projection of the small diameter portion 40 that protrudes from the small diameter hole 32 to the outside of the body 22 due to the positional relationship between the tip surface 28 of the cylindrical protrusion 26 and the step groove 44. The amount is configured to be visible.

A spring 52 is inserted into the medium diameter hole 34, and the spring 52 presses and urges the large diameter portion 42 of the spool 38 from the medium diameter hole 34 side to the large diameter hole 36 side.
A plug 54 is screwed into the large diameter hole 36 from the rear surface 24R side of the body 22. The plug 54 has a rod-shaped protrusion 56 having a diameter smaller than the inner diameter of the large-diameter hole 36, and the tip of the rod-shaped protrusion 56 regulates the moving range of the large-diameter portion 42 of the spool 38. A portion sandwiched between the plug 54 and the large diameter portion 42 in the large diameter hole 36 forms a pressure detection gas chamber 58.

A pressure transmission hole 60, an air supply hole 62, and a pressure adjusting hole 64 are formed in the plug 54 side portion of the large diameter hole 36.
The pressure transmission hole 60 opens in the bottom surface 24B of the body 22, and the opening portion of the pressure transmission hole 60 in the bottom surface 24B faces the opening portion of the air supply hole 9 in the top surface 7 of the back head 6, and is attached to this opening portion. The O-ring 68b seals between the pressure transmission hole 60 and the air supply hole 9.
The air supply hole 62 is opened in the upper surface 24T of the body 22, and the same air supply valve 46 that has been conventionally installed in the air supply hole 9 of the back head gas chamber 8 is installed in the air supply hole 62.

The pressure adjusting hole 64 is opened in the side surface 24S of the body 22, and a needle valve 48 is attached thereto. In the pressure adjusting hole 64, the exhaust gas hole 66 branches off from the position where the valve body of the needle valve 48 is located, and the exhaust gas hole 66 opens on the tip surface 28 of the cylindrical protrusion 26.
A male screw is cut on the outer periphery of the columnar protrusion 26, and a cap 50 having a female screw cut on the inner periphery is configured to be detachable from the columnar protrusion 26. An O-ring 68c is attached to the opening of the cap 50, and when the cap 50 is attached to the cylindrical protrusion 26, the O-ring 68c seals between the cap 50 and the front surface 24F of the body 22, and the cylindrical protrusion 26 is configured to be able to be sealed in the cap 50.

Next, the operation will be described.
First, a method for inspecting the gas pressure in the back head gas chamber 8 will be described. Since the back head gas chamber 8 communicates with the pressure detection gas chamber 58 via the air supply hole 9 and the pressure transmission hole 60, the gas pressure in the back head gas chamber 8 matches the gas pressure in the pressure detection gas chamber 58. . The gas pressure in the pressure detection gas chamber 58 and the urging force of the spring 52 act on the large diameter portion 42 of the spool 38. When the cap 50 is removed from the cylindrical protrusion 26, the distal end portion of the small-diameter portion 40 of the spool 38 corresponds to the distal end surface 28 of the cylindrical protrusion 26 according to the difference between the gas pressure in the pressure detection gas chamber 58 and the biasing force of the spring 52. Project from the body 22 to the outside. The amount of protrusion of the small-diameter portion 40 of the spool 38 is large when the gas pressure in the pressure detection gas chamber 58 is high, and is small when the gas pressure in the pressure detection gas chamber 58 is low.

  When the formation position of the step groove 44 of the small diameter portion 40 of the spool 38 is adjusted in advance, and the gas pressure in the back head gas chamber 8 is within the allowable use range, the leading end step portion and the rear end step portion of the step groove 44 are By keeping one point in between at the same position as the tip surface 28 of the cylindrical projection 26, the positional relationship between the tip surface 28 of the cylindrical projection 26 and the step groove 44 is visually confirmed, and the back head gas chamber 8 Can check gas pressure. That is, if the rear end side step portion of the step groove 44 protrudes from the front end surface 28 of the cylindrical protrusion 26 to the outside of the body 22, it can be seen that the gas pressure in the back head gas chamber 8 exceeds the allowable use range ( (See FIGS. 3 and 4). The gas pressure in the back head gas chamber 8 is within the allowable use range if one point between the front end side step portion and the rear end side step portion of the step groove 44 is at the same position as the front end surface 28 of the cylindrical protrusion 26. (See FIG. 5). If the step groove 44 does not protrude from the front end surface 28 of the cylindrical protrusion 26 to the outside of the body 22, it can be seen that the gas pressure in the back head gas chamber 8 is lower than the allowable use range (see FIG. 6).

  Next, a method for supplying and replenishing the inert gas to the back head gas chamber 8 will be described. The cap 50 is removed from the cylindrical protrusion 26, and the cylindrical protrusion 26 is exposed to the outside. Then, it is confirmed from the positional relationship between the tip surface 28 of the cylindrical protrusion 26 and the step groove 44 that the gas pressure in the back head gas chamber 8 is lower than the allowable use range. An inert gas cylinder is directly connected to the air supply valve 46, and the inert gas cylinder valve is opened to supply and replenish the back head gas chamber 8 with the inert gas. The inert gas flows into the back head gas chamber 8 through the air supply valve 46, the air supply hole 62, the pressure detection gas chamber 58, the pressure transmission hole 60, and the air supply hole 9. When the gas pressure in the back head gas chamber 8 rises and the gas pressure in the pressure detection gas chamber 58 rises, the tip portion of the small diameter portion 40 of the spool 38 protrudes from the tip surface 28 of the cylindrical protrusion 26 to the outside of the body 22. When the rear end side step portion of the step groove 44 of the small diameter portion 40 of the spool 38 is located at the same position as the tip end surface 28 of the cylindrical projection 26, the valve of the inert gas cylinder is closed.

When the inert gas cylinder valve is closed, the position of the step groove 44 of the small-diameter portion 40 of the spool 38 is visually confirmed, and it is confirmed whether or not the gas pressure in the back head gas chamber 8 is within the allowable use range.
When the gas pressure in the back head gas chamber 8 exceeds the allowable use range, the needle valve 48 is opened while looking at the position of the step groove 44 of the small diameter portion 40 of the spool 38, and the inert gas is removed from the pressure detection gas chamber 58. It discharges to the outside through the pressure adjusting hole 64 and the exhaust gas hole 66. When the inert gas is discharged to the outside, the gas pressure in the back head gas chamber 8 decreases, the gas pressure in the pressure detection gas chamber 58 also decreases, and the small diameter portion 40 of the spool 38 that protrudes outside the body 22 retracts. . Since the discharge amount of the inert gas can be easily finely adjusted by the needle valve 48, when the rear end side step portion of the step groove 44 of the small diameter portion 40 of the spool 38 is at the same position as the front end surface 28 of the cylindrical protrusion 26, The needle valve 48 is closed and the gas pressure in the back head gas chamber 8 is set within the allowable use range.

When it is confirmed that the gas pressure in the back head gas chamber 8 is within the allowable use range, the cap 50 is attached to the cylindrical protrusion 26 (see FIG. 7).
Since it is not possible to completely prevent a minute amount of inert gas from leaking from the back head gas chamber 8, the gas pressure in the back head gas chamber 8 is periodically inspected. When inspecting the gas pressure in the back head gas chamber 8, the cap 50 is removed from the cylindrical protrusion 26, and the amount of protrusion of the small-diameter portion 40 of the spool 38 protruding from the front end surface 28 of the cylindrical protrusion 26 to the outside of the body 22 is This is examined by the positional relationship between the step groove 44 of the small-diameter portion 40 of 38 and the tip surface 28 of the cylindrical protrusion 26. If the gas pressure in the back head gas chamber 8 is lower than the allowable use range, an inert gas is replenished from the air supply valve 46 to the back head gas chamber 8. Then, after confirming that the gas pressure in the back head gas chamber 8 is within the allowable use range, the cap 50 is attached to the cylindrical protrusion 26.

  Because of the gas pressure detection mechanism 20 as described above, an operator can inspect the gas pressure in the back head gas chamber 8 without using a pressure detection device such as a Bourdon tube pressure detector at the work site of the breaker. The gas pressure in the gas chamber 8 can be easily adjusted. Since the gas pressure in the back head gas chamber 8 can be easily adjusted, the inert gas can be supplied and replenished from the inert gas cylinder without using a regulator.

  While the breaker is in operation, the striking piston 10 reciprocates, and the gas pressure in the back head gas chamber 8 fluctuates. It is possible to prevent the spool 38 from moving due to fluctuations in the gas pressure in the head gas chamber 8. By preventing the spool 38 from moving, this reduces the wear of the O-ring 68a attached to the large diameter portion 42 of the spool 38, and the large diameter portion 42 and the large diameter hole 36 of the spool 38 are reduced. As a result, the spring 52 is prevented from being frequently expanded and contracted as the gas pressure in the back head gas chamber 8 fluctuates.

If the cap 50 is attached to the cylindrical protrusion 26 during operation of the breaker, it is possible to prevent the tip portion of the spool 38 from being worn or damaged by dust generated during operation of the breaker.
Further, when the gas pressure in the back head gas chamber 8 is not inspected, if the cap 50 is attached to the cylindrical protrusion 26, the cylindrical protrusion 26 is attached to the cap 50 and the body 22 by the O-ring 68 c of the cap 50. It can be sealed between the front surface 24F and the inert gas is prevented from leaking from the small diameter hole 32 or the exhaust gas hole 66.

It is an external view of the back head of a breaker provided with the gas pressure detection mechanism which concerns on this invention. It is the sectional view on the AA line of FIG. It is explanatory drawing of the gas pressure detection mechanism in the state where the gas pressure exceeded the allowable use range. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is explanatory drawing of the gas pressure detection mechanism in the state in which a gas pressure exists in a use allowable range. It is explanatory drawing of the gas pressure detection mechanism in the state in which the gas pressure fell from the allowable use range. It is explanatory drawing of the gas pressure detection mechanism equipped with the cap. It is a structural diagram of a conventional breaker.

Explanation of symbols

2 Breaker body 5 Cylinder 6 Back head 7 Back head upper surface 8 Back head gas chamber 9 Air supply hole in back head gas chamber 10 Stroke piston 20 Gas pressure detection mechanism 22 Body 24F Front of body 24R Rear surface of body 24T Upper surface of body 24B Body Bottom surface of the body 24S Side surface of the body 26 Columnar projection 28 End surface of the columnar projection 30 Through-hole 32 Small-diameter hole 34 Medium-diameter hole 36 Large-diameter hole 38 Spool 40 Small-diameter portion 42 Large-diameter portion 44 Step groove 46 Air supply valve 48 Needle valve 50 Cap 52 Spring 54 Plug 56 Plug-like rod projection 58 Pressure detection gas chamber 60 Pressure transmission hole 62 Air supply hole 64 Pressure adjusting hole 66 Exhaust gas hole 68a, 68b, 68c O-ring

Claims (3)

A body having a pressure detection gas chamber communicating with the breaker back head gas chamber;
A spool that is slidably fitted into the pressure detection gas chamber and configured to protrude at one end to the outside of the body by the gas pressure of the pressure detection gas chamber;
A spring that applies a biasing force against the gas pressure in the pressure detection gas chamber to the spool;
An air supply valve connected to the pressure gas chamber;
And a needle valve that adjusts the gas pressure in the pressure detection gas chamber . 2. The gas pressure detection mechanism according to claim 1, further comprising a cap that pushes a spool protruding outside the body into the body . A body having a pressure detection gas chamber communicating with the breaker back head gas chamber;
A spool that is slidably fitted into the pressure detection gas chamber and configured to protrude at one end to the outside of the body by the gas pressure of the pressure detection gas chamber;
A spring that applies a biasing force against the gas pressure in the pressure detection gas chamber to the spool;
Gas pressure test port mechanism you, comprising a cap pushing a spool protruding body outside inside the body, the.

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