JPH0229837B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates generally to civil engineering and road construction machines, and more particularly to air-actuated reversible percussion machines.

The present invention can find many advantages when applied to machines for drilling holes in the ground or for driving steel tubes into the ground used as casings for underground communications.

Other possible applications of the proposed air-actuated reversible impact machine include driving tubular piles into the ground, compacting deep-hole mud and driving multiple small piles directly into the ground. include.

BACKGROUND OF THE INVENTION A wide range of uses have recently been found in air-actuated reversible percussion machines, where reversibility is required for pulling the machine out of a hole and for driving the next tube into the ground. This is necessary to keep the machine away from the

The ever-increasing field of application of air-actuated reversible percussion machines demands improvements in the reliability of these machines. During horizontal drilling with lengths ranging from 15 m to 20 m, or during vertical drilling (such as compacting deep-hole mud or driving concrete piles into the ground), the extraction of the machine from the hole is complicated. In some cases, the mechanism for reversing impact action must be particularly reliable.

In order to increase its reliability, it is extremely important to keep the device structurally simple, which reduces the complexity of the extraction process, makes it cheaper to manufacture, and makes it more susceptible to rear impact effects. Ensures prompt switching.

a substantially hollow cylindrical housing; a hammer housed inside said housing for axially reciprocating motion and impacting the housing with its forward or rearward portion; A device is known (see German Patent No. 1,634,417) having a stepped tube connected to the tube by a threaded portion.

In order to reverse the impact action of such devices,
It is necessary to move the stepped tube to a new position towards the tail of the housing by rotating the air supply hose fixedly attached to the stepped tube.

Such devices are unreliable because the reversal is complicated or even impossible when passing through vertical or elongated horizontal holes.

The reversal of the impact action of the device also reduces the efficiency of the device since its operation involves stopping the supply of compressed air and pulling the air hose before disconnecting it from the compressor and rotating the air hose. requires numerous time-consuming actuations that affect

Also, other known impact actuators (West German patent no.
2340751), this machine consists of a hollow cylindrical housing, a hammer made to reciprocate within the housing and to impact on the housing with its front or rear part, and a fixed hammer. It comprises a stepped shaped tube which is securely fixed in a groove in the tail of the housing via means and connected to a hammer.

For the reversal of the impact action of the aforementioned machines, apart from the hoses, the use of flexible steel cables is made. By pulling on the cable, the action of the fixing means is removed and the stepped tube is moved to a new position. In other words, reversal is made possible by a simple linear movement of the stepped tube instead of a rotational movement.

However, the hose must be turned to bring the stepped tube out of engagement with the grooves and to place the stepped tube in line with the other grooves at its furthest position. As a result, the device disclosed in DE 2340751 essentially has the same drawbacks as the previously described devices.

A percussive machine is also known (see German Patent No. 2105229) which differs from the above-mentioned machine only in the configuration of the stepped tube. In this machine the stepped tube has an inner step having a plurality of radial through passages similar to an outer step having a plurality of radial through passages, said tube being rotatable and axial with respect to the outer step. It is coaxially fixed to the housing so that it can be moved in any direction.

The changeover to reverse impact action is here effected by turning the inner step relative to the outer step by supplying a large quantity of compressed air to the machine. This device offers several advantages over the devices already described in that it does not require rotation of the hose.

However, since multiple intermediate positions may be away from the forward and backward impact effects, a large supply of compressed air may be necessary if the operator is aware of the machine function following every continuous supply of compressed air or if the machine is fully operational. This machine is disadvantageous in that there will be some uncertainty as to whether or not it will. Another disadvantage is that this machine is structurally very complex and therefore difficult to manufacture.

The device most similar to the device proposed in the description that follows is an air-actuated reversing percussion machine as disclosed in German Patent No. 2722298. The machine includes a housing, a hammer that is axially reciprocatable within the housing and has an axial bore in its tail portion open at one end, and a radial passageway. The front working chamber of the hammer is defined by the housing. A stepped tube contained within the housing has a substantially cylindrical step of a larger diameter and a smaller diameter, the step having a radial passageway provided within the stepped tube.

A larger diameter step is placed in the axial bore of the hammer to delimit the rear working chamber, while a smaller diameter step is fixed in the tail section of the housing by a flange. A spring-loaded sleeve is placed precisely inside the stepped tube. An air supply hose serves as a means for controlling axial movement of the spring-loaded tube. The forward impact action of the machine is initiated when the sleeve is in its most forward position, and reversal is completed by moving the sleeve to its most forward position.

Since reversal is accomplished simply by tensioning the hose, and each element of the machine is always in a position to perform either a forward or reverse action, prior art percussion machines to date have This device generally eliminates the disadvantages inherent in the described structure.

However, even this device is not without some drawbacks. For example, the sliding action and pressure sealing of a sleeve on two of the multiple cylindrical surfaces of the device requires precise manufacturing of the mating surfaces, making the machine more difficult to manufacture. Also, the sliding of the sleeve along its two cylindrical surfaces is unreliable as it can become clogged, especially when dust adheres to such surfaces.

The machine also has a pressure-sealed interior comprising three isolated sections delimited by spring-loaded sleeves and stepped tubes. This interior must be made hermetically sealed as well for the accuracy of the sliding surfaces.

<Problem to be Solved by the Invention> It is an object of the invention to improve the reliability in reversing mechanical shock effects.

Another object is to provide an air-operated reversible percussion machine that is easy to manufacture.

A further object of the invention is to simplify the construction of the machine.

<Means for solving the problems> The above and other objectives and associated advantages are as follows:
a housing; a hammer disposed in the housing so as to be axially movable; having an axial recess open at one end in a tail portion thereof; and a radial through passage communicating with a forward working chamber formed between the housing; , comprising a first cylindrical step of larger diameter and a second cylindrical step of smaller diameter arranged coaxially with each other to form an annular recess, said first step forming a rear working chamber. the second stage is connected to the first stage at either end and connected to an air supply hose at the opposite end; a stepped-shaped air supply cylindrical tube; a spring-loaded cylindrical sleeve disposed for axial movement inside the annular recess of the air supply cylindrical tube; An air-operated reversible percussion machine comprising means for pressure-sealing an annular recess of a cylindrical tube, wherein a radial through passage is provided in the second stage of the air supply cylindrical tube, and the spring Hammer rear impact control means are provided which are capable of pulling the cylindrical sleeve biased by the spring in a direction opposite to the spring biasing direction and extend outwardly from the impact application machine, the position of said radial through passage being such that the location of said radial through passage is When the impact applying machine applies a forward impact, the through passage is closed by a sleeve moved forward by the action of a spring.
When the impact applying machine applies a rear impact, the through passage is opened by the sleeve moved rearward by the hammer rear impact application control means, and the air supplying cylindrical tube is positioned at a position where it can communicate with the annular recess. This is accomplished by an air-operated reversible percussion machine characterized by:

The proposed structure of the machine obviates sliding of the sleeve on the first cylindrical step of the tube, which prevents it from jamming during movement. Such construction does not require precision in finishing the outer surface of the sleeve and the surface of the first step, which has a large diameter and encompasses the sleeve.

This, on the other hand, makes the machine considerably simpler structurally,
To enable easy manufacturing. Providing an annular recess between the first stage of the tube and the sleeve prevents the sleeve from jamming during sleeve movement, which improves the reliability of the overall machine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Other objects and advantages thereof will become apparent from a more detailed description of preferred embodiments of the invention, given with reference to the accompanying drawings.

The air-operated reversible percussion machine comprises a housing 1 and a hammer 2 housed inside the housing 1 for reciprocating movement. At its caudal end,
The hammer 2 has an axial bore and a through passage 3. The hammer 2 delimits a front working chamber 4 with the housing 1 .

The housing 1 also houses a substantially cylindrical tube 5 of stepped shape, each having a large diameter cylindrical step 6 and a small diameter cylindrical step 7. These steps are arranged coaxially with respect to each other. Tube 5 is step 7
Housing 1 with flange 8 attached to
securely fixed to the tail section of the

The step 6 has a radial through passage 9, while the step 7 has a radial through passage 10 and an axial passage 11.
has. The stepped portion 6 provides a rear working chamber 12 for the hammer 2.
is placed inside the axial recess of the hammer 2 to delimit the axial recess of the hammer 2. The annular recess 13 is the tube 5
A cylindrical sleeve 14 is arranged between the step 6 and the step 7 and reciprocates axially over the step 7 in its annular recess 13. This cylindrical sleeve 14 has an outer diameter that is substantially smaller than the inner diameter of the step 6 in order to prevent contact between the sleeve 14 and the inner cylindrical surface of the step 6. sleeve 1
An annular passage 15 is formed between the tube 4 and the step 6, and a spring 16 is mounted on the step 7 of the tube 5. One end of the spring 16 is carried on the flange 8 and the other end is carried on the end surface of the sleeve 14. Means for pressure-sealing the recess 13 are provided by an elastic sealing element 17 arranged on the end surface of the sleeve 14.
and a seat surface 18 in the inner part of the step 6. The movement of the sleeve 14 is carried out by the steel cable 1.
9 (FIGS. 1 and 2) or by a tube 20 (FIG. 3), one end of which is connected to an air supply hose 21. The other end of the tube 20 is connected to the sleeve 14 using a pin 22 fixed to the passage 10;
Movement in the axial direction relative to the step 7 is possible.

An internal area 23 is provided in the housing 1 between the hammer 2 and the flange 8, which can communicate with the outside world through a hole 24 made in the flange 8.

The proposed device operates as follows.

(a) In the case of a front impact action of the machine The normal position of the sleeve 14, i.e. its most extreme position with respect to the head end of the device, is maintained by the spring 16 (FIG. 1). This position of the sleeve 14 corresponds to the front impact action of the machine. The initial position of the hammer within the housing 1 is arbitrary. Cable 19 is not under tension. Prior to operation, the machine is coupled to a compressor (not shown). By means of the hose 21 the machine was oriented in the desired direction and provided with a slight sharp point at the front created by a special contraption or by a simple lever.
Pressed against the land that is to be dug.

Thereafter, the outlet valve of the compressor is opened to allow compressed air to flow through the hose 21, the axial passage 11 of the tube 5, and into the rear working chamber 12. The compressed air acts to move the hammer 2 until it rests on the end surface of the head portion of the housing 1, opening the radial passages 3 of the hammer 2 as shown in FIG. The compressed air then enters the forward working chamber 4. Since the working surface area of the hammer 2 on the side of chamber 4 is larger than the surface area on the side of chamber 12,
When equal pressures are applied to the two chambers 4 and 12, the force applied to the hammer 2 on the chamber 4 side is greater than the force acting on the chamber 12 side. Under the action of the resulting force, the hammer 2 moves against the flange 8.
(toward the right hand side in Figure 1).

After closing the radial channel 3 by the cylindrical step 6, i.e. even after stopping the supply of compressed air to the chamber 4, the hammer 2 is still subjected to the pressure of the expanded air in the chamber 4. and continue its movement. When the radial passage 3 of the hammer 2 coincides with the radial passage 9 of the step 6, air is admitted from the chamber 4 through the passage 3 and the passage 9 into the recess 13;
It then enters the interior area 23 and escapes to the outside world through holes 24 in the flange 8.

Since there is no pressure in the chamber 4, while the chamber 12 is continuously exposed to the pressure of compressed air, the hammer 2 is moved towards the head end of the housing 1 (first
to the left (as seen in the diagram) and impact the inner end surface of the housing.

At the moment of impact, chamber 4 is filled with compressed air in the manner described above, and the cycle described above is thus repeated.

The impact action on the housing 1 causes the machine to penetrate into the ground (if digging a hole) or, if the machine is coaxially connected with a steel pipe, to drive the steel pipe into the ground.

(b) In the case of backward action of a machine. Such a reversal is usually required to return a machine from a hole previously made by it.

In order to switch the machine into rear shock action, the cable 19 can be connected without stopping the compressed air supply.
applying a tensile force to (Figures 1 and 2);
By overcoming the compressive force of the spring 16, the sleeve 14 moves to the rearmost position of the sleeve.
In other words, it is necessary to move it from the position shown in FIG. 1 to the position shown in FIG.

In this latter position, the elastic sealing element 17 is in full contact with the seat surface 18, whereby the annular recess 13 is pressure-tightly sealed. This opens the radial passage 10 of the cylindrical step 7, which changes the function of the radial passage 9 of the step 6 and the annular recess 13. More specifically, those parts will be moved away from the system of exhaust channels and into engagement with the system of channels supplying compressed air to the working chamber 4.

In the relative arrangement of the several elements in the proposed machine shown in FIG.
1 into the rear working chamber 12 and through the radial passage 10 into the annular recess 13 . The pressure of the compressed air in the annular recess 13 acts on the sleeve 14 to press the sealing element 17 against the seating surface 18 of the step 7, keeping it in that position and thus counteracting the compressive force of the spring 16. You're winning.

By the action of the pressure of the compressed air in the chamber 12,
The hammer 2 begins its movement towards the end face of the head end of the housing 1. When the radial passage 3 of the hammer 2 is moved into alignment with the radial passage 9 of the step 6, compressed air will flow from the annular recess 13 into the chamber 14. This thing is hammer 2
The hammer 2 is stopped at a certain distance from the flange 8 of the housing 1 by decelerating its movement.

When the chamber 4 is filled with compressed air, the hammer 2 moves towards the flange 8 and impacts it. At the moment of impact, the compressed air passes from the chamber 4 through the radial passage 3 of the hammer 2 and into the second
Internal area 2 as best shown in the figure
3 and then escapes to the outside world through a plurality of holes 24 in the flange 8.

Following the impact on the flange 8, the hammer 2 releases air in the chamber 12 so as to start moving the hammer towards the head end of the housing 1, in order to restart the cycle in the manner described above. Driven by pressure.

Reliable reversibility of the impact action of the proposed machine is ensured when the following conditions are met:

P ₁ > P _r (1) P _a > P ₂ + P _r (2) where P ₁ is the initial compression force of the spring 16, P ₂ is the final compression force of the spring 16, and P _r is the mechanical (Figure 3).

P _a is the force generated by the pressure of the compressed air in the annular recess 13 that acts to press the sleeve 14 toward the seat surface 18 .

The changeover to the reverse operation of the proposed machine can be carried out both before starting and during operation in the forward impulse mode of operation without stopping the supply of compressed air to the machine.

During the rear impact action of the machine, the annular recess 13
is continuously under the pressure of compressed air, which ensures continuous closure of the annular recess 13 by the sleeve 14, so that the sleeve 14 is brought into contact with the seat surface 18.
to ensure a stable position.

Opening of the annular recess 13, i.e. communication with the atmosphere, is only possible when the supply of compressed air is stopped, which requires moving the sleeve by means of the spring 16 into the position shown in FIG. enable.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a pneumatic reversible percussion actuator according to the invention, showing the mutual position of the elements corresponding to the forward percussion action of the machine. FIG. 2 is a longitudinal sectional view similar to FIG. 1 showing the mutual positions of the elements in the reversing action of the machine according to the invention. FIG. 3 is a longitudinal sectional view showing another embodiment of the machine according to the invention. DESCRIPTION OF SYMBOLS 1...Housing, 2...Hammer, 3...Radial through passage at the tail end of the hammer, 4...Front working chamber, 5...Stepped shaped tube, 6...Large diameter cylindrical step of tube 5, 7... Small diameter cylindrical step of tube 5, 8...flange, 9...radial through passage of cylindrical step 6, 10...radial through passage of cylindrical step 7, 11...axis of cylindrical step 7 directional passage,
DESCRIPTION OF SYMBOLS 12... Rear working chamber, 13... Annular recess between step part 6 and step part 7 of tube 5, 14... Sleeve, 15... Annular passage, 16... Spring, 17... Sealing element, 1
8...Seat surface, 19...Cable, 20...Tube, 2
DESCRIPTION OF SYMBOLS 1... Compressed air supply hose, 22... Pin, 23... Internal area, 24... A plurality of holes in flange 8.

Claims (1)

[Claims] 1. A front working chamber 4 formed between the housing 1 and the housing 1 and an axial recess that is disposed within the housing 1 so as to be movable in the axial direction and has one end open at the tail portion thereof. a first cylindrical step 6 of large diameter and a second cylindrical step 7 of small diameter arranged coaxially with each other to form an annular recess 13; The first step portion 6
the hammer 2 so as to form a rear working chamber 12.
The second stage 7 is connected to the first stage 6 at either end and to an air supply hose at the opposite end. Stepped air supply cylindrical tube 5
and an annular recess 13 of the air supply cylindrical tube 5.
a cylindrical sleeve 14 disposed for axial movement inside the tube and biased by a spring, and means 17, 18 for pressure-sealing the annular recess 13 of said cylindrical tube 5; In the reversible impact machine, the second step 7 of the air supply cylindrical tube 5
a hammer rear shock application control means having a radial passageway 10 therethrough and capable of pulling the cylindrical sleeve 14 biased by said spring 16 in a direction opposite to the spring biasing direction and extending outwardly from the impact machine; 19 and 20 are provided, and the position of the radial through passage 10 is closed by the sleeve 14 which moves the through passage 10 forward by the action of the spring 16 when the impact applying machine exerts a forward impact, so that the impact is not applied. When a rear impact is applied to the machine, the through passage 10 is opened by the sleeve 14 moved rearward by the hammer rear impact control means 19, 20, and the air supply cylindrical tube 5 communicates with the annular recess 13. An air-operated reversible percussion machine, characterized in that it is located in a position where it can be used.