JPH06328371A - Fluid operated shock hammer - Google Patents

Abstract

PURPOSE: To provide a fluid operation impact hammer capable of not only advancing an object into the ground effectively but also simplifying pulling out greatly. CONSTITUTION: A work piston 22 gives an impact to a transmission element 23 connected with a drill rod to advance a drill pipe. When the drill rod is pulled up, the impact of the work piston 22 does not reach the transmission element 23. A control means 54 advancing a stop member 51 that the work piston 22 hits during return stroke is additionally provided at a rear end of a work cylinder 21. When the drill rod is pulled out, pulling out can be done easily because the operation is done by the impact of a hammer applied rearward.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fluid operated impact hammer for advancing an object into the ground, and more particularly to an impact hammer used for advancing a drill column into the ground.

[0002]

From German patent application 25 12 731 and German patent application 245 61 633 a hydraulic hammer with a working piston movable in a working cylinder is known. The working piston makes a working stroke and at the end of the stroke hits the anvil connected to the drill column,
Then, the return stroke is performed. The working stroke and the return stroke of the working piston are controlled by the control piston, which is controlled by each position of the working piston. Such an impact hammer is suitable for effectively advancing an object into the ground.

[0003]

Difficulties often arise when pulling an object, such as a drill tube, out of the ground again. The conical drill bit is located at the lower end of the drill rod. When pulling out the drill rod, this drill bit is firmly embedded in the boring hole like a peg. During normal withdrawal, an impact hammer is activated to vibrate the drill column and release the tube. However, in the conventional case, it took a long time to pull out. It is an object of the present invention to provide a fluid-operated impact hammer that not only advances an object effectively into the ground, but also greatly simplifies withdrawal.

[0004]

SUMMARY OF THE INVENTION An impact hammer according to the present invention comprises a hammer housing having a working cylinder in which a working piston is movable, and a pressure fluid introduced into the working cylinder so that the working piston works forward. Control means for alternately performing the stroke and the return stroke,
A fluid-operated impact hammer for advancing an object into the ground, comprising a working piston for striking a transmission element during a working stroke and transmitting an impact to an object to be advanced, the control means comprising: In the operating state, the working piston strikes a rear stop provided in the hammer housing during the return stroke.

[0005]

The impact hammer according to the present invention can use the same operation mode as a normal impact hammer, and the working piston strikes the transmission element attached to the tip. Furthermore, with this impact hammer, a working mode can also be used in which the working piston exerts an impact even during the return stroke, in which case the impact acts in the opposite direction. Such switching between the two operation modes is performed by the control means. Therefore, the impact hammer according to the present invention can be said to be a so-called double impact hammer in which impact can be switched bidirectionally.

When a shock is applied to the rear side, not only vibration is generated but also a rearward shock is generated, which facilitates the release of the object to be pulled out. In the case of a backward stroke, the flow line of the work cylinder in the work piston becomes shorter, or the flow line of the return stroke of the work piston becomes longer due to, for example, a delay in switching. on the other hand,
In normal operation, the working piston strikes the transmission element attached to the tip, slows down hydraulically during the return stroke, and during the backward operation the working piston strikes the hammer housing, so that the hammer housing moves backwards. It accelerates and pulls the object to be pulled out which is connected to the hammer housing.

The invention finds particular application in drilling with rotary drill columns, but is also suitable for advancing and withdrawing other objects, for example sheet pile stakeout. The impact hammer is preferably configured as an external hammer at the rear end of the drill tube, but can also be configured as a deep digging hammer attached near the drill bit in the drill rod.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The drill hammer shown in FIG. 1 comprises a hammer housing 20 containing a working cylinder 21. The working piston 22 is guided into the working cylinder 21. The tip of the working piston 22 strikes a transmission element 23 which is guided in the hammer housing 20 so that it can be moved in a limited direction in the longitudinal direction. The transmission element 23 is the end shank of the drill column and the tube of the drill column is attached to the thread 24 of the end shank. "Front" is the direction towards the drill column and "rear" is the opposite direction.

The working piston 22 has a forward facing annular working surface 25 which bounds a front cylinder space 26. This cylinder space 26 is in constant communication with the pressure line P via line 27. The working surface 25 bounds the enlarged portion 28 of the working piston. The other boundary of the enlarged portion 28 is formed by the working surface 29 joined to the reduced portion 30. Reduction unit
30 continues to another enlargement 31 and the rear end of enlargement 31 is a work surface 32
Formed by. The working surface 32 delimits a rear cylinder space 33 of the working cylinder 21. The work surface 32 is larger than the work surface 25.

The work cylinder shank 22a is a work surface 25
From the work surface 32 to the rear. The working surface 25 moves in the front cylinder space 26 along the control groove 34. The work surface 29 moves along the control groove 35. In the region of the work piston reducing section 30, a line 36 connecting to the return line R opens into the work cylinder 21. The control grooves 34 and 35 connect to the control line 27. The rear cylinder space 33 of the working cylinder is connected to the operating line 38.

The control of the working piston 22 is controlled by a control cylinder.
This is done by means of a control piston 41 which can move in 40. The control piston is formed as a hollow sleeve. Since the control cylinder 40 is connected to the pressure line 27, a sufficient hydraulic pressure is always maintained inside the control piston 41. One end of the control piston 41 is provided with a first working surface A1 provided with radial grooves that are constantly pressurized and are equally pressured. The other end of the control piston is provided with a second working surface A2 smaller than the first working surface A1. The control piston is provided with an annular collar 42 bounded at one end by a control surface A3 and at the other end by a return line R and always defined by a pressure-free control surface A4. The control surface A3 is pressurized in the control line 37. The control piston 41 also has an annular groove 43 which communicates with the return line R at any position of the working piston. The pressure line 27 is connected to a gas pressure reservoir 44 which acts as a shock absorber for smoothing hydraulic shocks.

The operation of the impact device will be described below. In the situation as shown in FIG. 1, the operating line 38 communicates with the pressure line 27 via the interior of the control piston 41, so that the total pressure acts on the work surface 32. Work surface 32 is work surface 25
And the total pressure also acts on the work surface 25, so that the work piston 22 makes a work stroke towards the front,
The transmission element 23 is hit with the tip of the piston. As soon as the control surface 25 passes through the control groove 34, the control line 37 is disconnected from the pressure line 27. When the control surface 29 passes through the control groove 35, the control line 37 is connected to the line 36 via the control groove 35 and the pressure is released. Therefore, no pressure acts on the control surface A3 of the control piston 41.

In FIG. 1, the control piston moves upward because the force acting on the work surface A1 is greater than the force acting on the work surface A2 by the same pressure. When the control piston reaches the upper end position, the operating line 38 is separated from the supply pressure and is connected to the return line R via the annular groove 43. This initiates the return stroke of the working piston 22. During the return stroke, the groove 35 is blocked by the enlarged portion 28 of the piston and the groove 34
As soon as is released by the working surface 25, all the pressure builds up in the control line 27 and acts on the control surface A3, driving the control piston in its lower end position. The total of control surfaces A2 and A3 is greater than control surface A1.

Assume that the hammer housing 20 is pushed forward to advance the drill rod.
Since the drill rod is supported only by the boring holes, the transmission element 23 is pushed into the hammer housing 20. The axial movement of this transmission element is delimited by a keyway 45 which allows limited movement within the recess 46 of the hammer housing 20. When the hammer housing 20 is moved forward, the transmission element 23 is brought to the rearmost position, so that the shank 22a of the working piston functions as an anvil and impacts the transmission element 23. With each impact, the transmission element 23 moves axially in the free space bounded by the hollow space 46. However, when the hammer housing 20 is pulled out, the transmission element 23 assumes the tip position in the hollow space 46. In this case, the shank 22a of the working piston does not reach the transmission element. The forward movement of the working piston is somewhat slowed by the damping of the hydraulic medium enclosed in the front cylinder space 26.

The rear shank 22b of the working piston projects into the hollow space 50 of the hammer housing 20. From the opposite side, ie from the rear, a stop member 51 with a piston 52 moving in a cylinder 53 projects into the hollow space 50. Piston 52 and cylinder 53 are working pistons
It serves as a control means 54 for changing the length of the flow line when 22 enters the working cylinder. The front and rear cylinder spaces of the cylinder 53 are connected to control valves 57 via lines 55 and 56, respectively, which control the piston 52 by exerting pressure on these lines. When line 56 is pressurized and line 55 is depressurized, piston 52 is driven to the front end position, advancing stop member 51 to that position. Working piston 22
Strikes the stop member 51 during the return stroke. The impact is transmitted to the hammer housing 20 via the hydraulic medium sealed in the rear part of the cylinder 53, and the hammer housing 20 can obtain a rearward impact. However, when the piston 52 is at the rear end position, the working piston 22 does not reach the stop member 51 because the working piston 22 is switched too quickly, so that no impact is applied to the stop member.

When advancing the drill column, the piston
52 is at the rear end position, and the transmission element 23 is also at the rear end portion. During the working stroke, the working piston 22 is the transmission element
23 but strikes the working piston 22 during the return stroke.
Does not reach the stop member 51.

When pulling out the drill column, the hammer housing 20 is pulled out, the transmission element 23 is located at the tip of the hammer housing and cannot be reached by the working piston 22 during the working stroke. Since the piston 52 is at the tip position, the stop member 51 is advanced in the working cylinder. There, the working piston impacts the stop member 51 and impacts the hammer housing 20 on the return stroke.

The control valve 57 operates properly according to the moving direction of the hammer housing 20, and when the hammer housing 20 is pulled out, the stop member 51 is automatically fed forward, and when the hammer housing 20 is pushed forward, the stop member 51 is pushed.
Is pulled back.

In the embodiment of FIG. 2, the control means 54a comprises a wedge-shaped stop member 58 which is movable at right angles to the working cylinder 21 and which forms the stop surface of the shank 22b of the working piston. The stop member 58 is guided on the inclined surface 59 and engages from the side surface.
Move at a right angle to the work cylinder. Therefore, the position of the stop surface 58a with respect to the axis changes. The piston type cylinder unit 60 is controlled so that the stop member 58 can be held not only at its both ends but also at any position in the middle. Therefore, the position of the stop surface 58a can be adjusted steplessly. In this way, the impact energy when the working piston strikes the stop member 58 can be changed. The piston type cylinder unit 60 is controlled by an external control valve.

In the embodiment of FIG. 3, the control means is a control line 37.
And a valve installed between the control groove 34 and the control groove 34.
Although the slide valve 62 is provided inside, the slide valve 62 can block the pipe line portion 37a to invalidate the control groove 34. The control groove 34a is attached to the rear of the control groove 34 and is always connected to the control conduit 37 to take over the function of the control groove 34. In the case of the forward movement operation of the drill device, when the control surface 25 passes through the control groove 34, the end movement of the return stroke of the working piston is started. The working piston then performs the rest of the return stroke, with the shank 22b not reaching the rear end of the hollow space. However, when the hammer housing is pulled out, the conduit 37a is closed. Since the switching is performed not by the control groove 34 but by the control groove 34a located further rearward, the switching from the return stroke to the forward stroke is delayed. In this way, the shank 22b strikes one end of the hollow space 25, allowing the working piston to impact the hammer housing 20 during the return stroke.

The slide valve 62 of the control means 54b can be operated hydraulically or pneumatically, but it can also be operated electromagnetically or manually.

[0022]

With the apparatus of the present invention as described above, the object can be pulled out quickly and easily. And its structure is also simple.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of an impact hammer.

FIG. 2 is a longitudinal sectional view showing a modified example of the control means attached to the rear end of the hammer housing.

FIG. 3 is a vertical sectional view showing a third embodiment of the impact hammer.

[Explanation of symbols]

 20 Hammer housing 21 Working cylinder 22 Working piston 23 Transmission element 40 Control cylinder 41 Control piston 51 Stop member 54 Control means

Claims (7)

[Claims] 1. A hammer housing (20) having a working cylinder (21) in which a working piston (22) is movable, and a pressure fluid is introduced into the working cylinder (21), and the working piston (22) is moved forward. Control means (40, 41) for alternately performing a work stroke and a return stroke to the work piston and the work piston that transmits a shock to the object to be advanced by striking the transmission element (23) during the work stroke. 22), in a fluid-operated impact hammer for advancing an object into the ground, comprising control means (54, 54a, 54b), in its operating state, the working piston (22) during the return stroke. A fluid-operated impact hammer characterized by hitting a rear stop provided in a hammer housing. 2. The transmission element (23) is guided on the hammer housing (20) and can move in the direction of impact, and remains at the tip when the hammer housing (20) is pulled out, and the working piston (22). The impact hammer according to claim 1, wherein the impact hammer does not reach. 3. The control means (54, 54a) is attached to the rear end of the work cylinder (21), and the control means (54, 54a) of the work cylinder (21) is arranged to change a moving distance in the work cylinder (21). Impact hammer according to claim 1, comprising stop members (51, 58) which are adjustable in the longitudinal direction. 4. The stop member (51) is a piston (52).
The impact hammer according to claim 3, further comprising a cylinder hydraulically supported in the hammer housing (20). 5. The impact hammer according to claim 3, wherein the stop member (58) comprises a wedge movable at a right angle to the working cylinder (21). 6. Impact hammer according to claim 1, wherein said control means (54b) comprises a blocking element (62) for delaying the switching of the working piston (22) from a return stroke to a working stroke in the activated state. 7. The actuation of the control means (54, 54a, 54b) is such that the impact of the return stroke acts only on the rearward movement of the hammer housing (20) of the hammer housing (20). The impact hammer according to claim 2, wherein the impact hammer is aligned with the moving direction.