WO2011023350A1

WO2011023350A1 - Drilling ram device having a pneumatic drive and a hydraulic reversal of the movement direction

Info

Publication number: WO2011023350A1
Application number: PCT/EP2010/005151
Authority: WO
Inventors: Gerhard Völkel
Original assignee: Tracto-Technik Gmbh & Co. Kg
Priority date: 2009-08-24
Filing date: 2010-08-23
Publication date: 2011-03-03
Also published as: DE102009038385B4; DE102009038385A1

Abstract

The invention relates to a pneumatically driven drilling ram device, the movement direction of which is hydraulically reversed. For this purpose, a pressure medium can be piped over a hydraulic line (12) to a pressure chamber (11), the longitudinal axial extent of which influences the middle position of the reciprocating, pneumatically driven impact piston (3), such that the impact piston strikes either against a front (4) or rear (5) impact surface and accelerates the drilling ram unit in the corresponding direction. In an advantageous embodiment, the pressure medium is discharged into the ground in front of the drilling ram device, in order to soak the ground and to improve the drilling progress.

Description

"Rammbohrvorrichtung with a pneumatic drive and a hydraulic reversal of the direction of movement"

The invention relates to a ram boring device with a pneumatic drive and a hydraulic reversal of the direction of movement. Rammbohrvorrichtungen, as used in particular for the production of horizontal

Ground bores are usually driven by means of a percussion piston, which is reciprocated within the housing and thereby bounces, depending on the desired direction of movement of the device on a front or rear impact surface. The transmitted thereby kinetic energy of the percussion piston ensures an acceleration of the ram boring device within the soil.

In general, a reversal of the direction of movement is achieved in that the middle position (between the two turning points) of the percussion piston from a front to a rear position - or vice versa - is moved. Thus, depending on the position, the percussion piston strikes either the front or rear striking surface and thereby defines the direction of movement of the device.

Various designs are known from the prior art, with which the center position of the percussion piston displaced and consequently the direction of movement of the device can be changed. For example, from DE 39 09 567 A1 a ram boring device is known in which a control tube is firmly connected to a compressed air supply. The control tube is connected both longitudinally and rotationally via a prestressed helical spring with a housing-fixed component. The spring forces the head tube, on which a percussion piston is arranged to be axially movable, in a forward position (preliminary position) and locks it in this position by a quarter turn into a corresponding locking groove. To redirect the device, the control tube is unlocked by a quarter turn of the compressed air supply against the spring bias, so that the control tube under the influence of compressed air and against the longitudinal axial spring force in a rear position (return) is moved. As in the front position, the control tube locks there under the influence of the rotationally biased spring.

To switch back to flow, the control tube is again rotated by means of compressed air supply and also the amount of air pressure is lowered so far that the longitudinal axial spring force exceeds the force acting on the control tube by the compressed air. Thus, the head tube automatically moves to its forward position.

For reversing a Rammbohrvorrichtung according to DE 39 09 567 A1 thus the control tube must be rotated by a rotation of the compressed air supply and in addition the height of the air pressure to be temporarily lowered.

Another example of a reversal of a pneumatic Rammbohrvorrichtung describes DE-OS 21 05 229. On a control sleeve sits axially displaceable a percussion piston. The control socket has a plurality of control ports, which are partially attributable to the flow and partly the return. A control tube through the interior of which compressed air is supplied to the device and which likewise has control openings which, depending on the rotational position of the control tube, coincide with a part of the control openings in the control sleeve is located within the control socket. A coil spring, which is arranged between the control tube and the control sleeve, forces the two components into a mutual, defined by a tongue and groove combination

End position.

The groove is seated in the inside of the control sleeve and has a zigzag-shaped course, so that the control tube carries out a combined rotary and translatory movement with the spring moving in the groove.

Switching the direction of movement now takes place in that the compressed air supply is temporarily switched off. As a result, the spring moves the control tube relative to the control sleeve in a turning tip of the zig-zag groove. If the compressed air is switched on again, the control tube is again against the spring force in the next

Turned tip of the groove pushed. Every turn-off cycle will turn that Control tube relative to the control sleeve by 90 °. Now overlap either the control ports for the flow or the return of the two components. The ram boring device moves either forward or backward. By turning off and on again, the control tube and the control sleeve in turn rotate against each other by 90 °, so that the other control openings of the two components overlap. The direction of movement of the device was reversed.

The reversal of a device according to DE-OS 21 05 229 requires switching off the compressed air supply. This can cause problems when restarting the

Percussion piston result. There is also the risk that water and soil penetrates into the device due to the short-term lack of pressure in the device. In both cases, the ram boring tool must then be recovered by excavation, which results in a significant additional effort and a considerable loss of time.

The invention is based on the object to provide an improved pneumatically driven Rammbohrvorrichtung whose direction of movement can be switched without affecting the compressed air supply.

This object is solved by the subject matter of the independent claims. Advantageous embodiments are mentioned in the dependent claims.

The invention provides a ram boring device, which is driven pneumatically by means of a drive pressure gas supplied via a first supply line (preferably compressed air), by means of a pressurized fluid, which is supplied to the ram boring device independently of the drive pressure air, from the flow in the return and vice versa. The reversing can thus take place without influencing the supply of the driving pressure gas.

A ram boring device according to the invention therefore has at least one percussion piston mounted within a housing and driven in a cyclical reciprocating motion by a drive pressure gas, in particular striking the ram boring device in a first direction of movement to drive, and in a second switching position impinges on a rear impact surface to drive the ram boring device in a second direction of movement, and wherein the switching between the directions of movement is effected by shifting the central position of the percussion piston within the housing. The ram boring device according to the invention is further characterized in that the shifting of the middle ren position of the percussion piston by a pressurized fluid, which is supplied to the ram boring device independently of the drive pressure air.

By "ram boring" is meant any device which is moved intermittently in an existing or created conduit to create or expand a bore or destructively or non-destructively replace or clean an existing conduit, conduits into existing conduits or others Long bodies to collect as well as all devices for construction work of the underground tunneling.

The ram boring device according to the invention is not limited to underground earthworks. Thus, for example, lines in which a Erdbohrgerät is operated, run above ground. In a preferred embodiment of the present invention, it is provided that the reversal of the impact stroke hydraulically, i. by supplying a Drucktlüs- sigkeit takes place. The use of a pressure fluid has the advantage that it is substantially incompressible and therefore exact control of the position of the percussion piston within the housing of the device can be easily implemented.

Of course, it is also possible to use a compressed gas and in particular compressed air for reversing, which is supplied to the ram boring device by an additional supply line and optionally with a different pressure level than the driving pressure gas.

In an advantageous embodiment of the device according to the invention, a guide tube is provided which can be directly or indirectly immovably connected to the housing of the ram boring device. On the guide tube, a control sleeve and on the control sleeve, a percussion piston can be arranged in each case axially displaceable.

The percussion piston can reciprocate on the control sleeve under the influence of the supplied drive-pressure gas, with control openings being opened and closed at a regular time interval and thus successively connecting or disconnecting different working chambers of the ram-boring device to the drive-pressure gas.

The outer surface of the guide tube and the inner surface of the control sleeve can form an annular pressure chamber with correspondingly arranged annular edges, which is filled by a pressurized fluid and in particular a pressure fluid. The Size of the pressure chamber is defined by the relative longitudinal axial position of the two components to each other and can be varied by appropriate displacement. For fixing or varying the size of the pressure chamber, it is provided to vary the height of the pressure of the pressure fluid as a function of the external pressure or another counterforce, for example a spring force.

The pressure chamber may have any shape in addition to the ring shape. In particular, the pressure chamber can be formed only by a partial circle of the outer or inner circumference of the guide tube or the control sleeve.

The size of the pressure chamber defines the mean position of the reciprocating percussion piston in the housing. Thus, it can be influenced directly via the height of the pressure of the pressurized fluid, whether the percussion piston impinges on a front or rear impact surface of the ram boring device.

In addition, since the erfindungsgsrnäße control allows to adjust the miniere position of the percussion piston steplessly, the stroke of the percussion piston and consequently its frequency and its impact intensity can be influenced. To supply the pressure chamber with the pressure fluid may be provided to arrange an additional fluid line within the head tube.

In an advantageous embodiment of the device according to the invention, in which a reversal takes place hydraulically, it is provided that the fluid line is designed as a hydraulic line and leads to at least one outlet opening for the pressure fluid in the region of the drill head. For this purpose, the hydraulic line can be guided by the percussion piston, whose end face has a corresponding through hole. The outlet opening for the pressure fluid can serve to flush a rinsing liquid in the

Introduce area of the drill head in the soil, so that it is softened and can be displaced easier. In addition to water drilling fluids can be used as a rinsing liquid, whose properties can be adapted to the respective drilling conditions by adding additives.

In an advantageous embodiment of the invention, the drill head on a plurality of outlet openings, which are advantageously arranged in a circle in a uniform pitch on the circumference of the drill head. It can thereby be achieved that the rinsing liquid is introduced as evenly as possible into the soil in the area of the drill head. In a further advantageous embodiment, it is provided to discharge the rinsing liquid under pressure from the ram boring device on one side. The resulting lateral force leads to a lateral deflection of the device, which can be used for a direction correction.

In the case of a plurality of outlet openings arranged in a circle, means, for example switchable multi-way valves, can be provided with which the flushing agent flow through the individual outlet openings can be regulated. Advantageously, a pressure limiting valve can be arranged in the hydraulic line, in particular in the section between an inlet for the pressure chamber and the outlet opening or openings in the region of the drill head.

The pressure-limiting valve can serve, for example, to shut off the outlet openings from the pressure supply up to a certain pressure level in the hydraulic line. Thus, only after exceeding sinss limit value dss pressure rinsing liquid is introduced into the soil. In the pressure range below the limit value, the fluid pressure can thus be used exclusively for reversing the direction of movement.

In a preferred embodiment, the pressure chamber is designed so that at a high pressure, the control sleeve is displaced together with the percussion piston in the direction of a switching position for forward movement of the ram boring device. If, on the other hand, the pressure is lowered further, the control sleeve, together with the percussion piston, shifts under the influence of the drive air or another force and against the fluid pressure in the pressure chamber in the direction of a switching position for a backward movement of the device.

By such an embodiment of the pressure chamber can be achieved in conjunction with a pressure relief valve in the hydraulic line that the outflow of

Rinse liquid is stopped in the soil in the reverse operation of the device.

In addition, by means of a corresponding design of the pressure limiting valve, the outflow of rinsing liquid into the ground can be switched on or off in the forward operation of the device without triggering a reversal of the direction of movement of the device. Depending on the required switching state of the flushing agent outflow, the hydraulic pressure can be adjusted either above (flushing agent outlet switched on) or just below (flushing agent outflow switched off) of the limit value of the pressure limiting valve. The switching position of the pressure chamber can remain unaffected. The device according to the invention makes it possible to operate a ram boring device pneumatically with as uniform a pressure as possible in terms of pressure and / or volume flow, and to carry out the reversal of the direction of movement by means of a pressurized fluid supplied independently of the drive pressure gas. As a result, incorrect control can be prevented due to fluctuating pneumatic pressure of the drive gas. In addition, a pulling or turning on the compressed air supply, as is usually provided in the prior art for the reversal of the direction of movement, omitted. It is particularly advantageous if a pressure fluid, which is used for reversing the direction of movement, is introduced into the soil in order to soften it and / or to generate a lateral force, which is utilized for directional control of the device. The invention will be explained in more detail below with reference to an exemplary embodiment shown in the drawings.

In the drawings: FIG. 1 shows a sectional side view of a ram boring device according to the invention;

Fig. 2: the rear portion of the ram boring of Fig. 1 in an enlarged view and

3 shows the front portion of the ram boring apparatus of Fig. 1 in an enlarged view.

The illustrated embodiment of a ram boring device according to the invention consists essentially of a housing 1, in which a drill head 2 is screwed. One

Percussion piston 3 reciprocates under the influence of compressed air in the housing, the percussion piston 3 within each period, depending on its central position (between the two turning points), either on a front

Striking surface 4 or a rear impact surface 5 hits. The transmitted shock energy leads to an acceleration of the housing. 1

The middle position of the percussion piston 3 and consequently the direction of movement of the ram boring device is determined by the position of the control sleeve 6. The control sleeve 6 is seated within the percussion piston 3 and, depending on the position of the two

Components to each other, conceals or gives control openings 7 in the wall of Schlagkol- bens 3 free. With open control openings 7, the outer working chamber 8 fills with compressed air, so that the percussion piston 3 due to the larger area compared to that of the inner working space 9 in the direction of the rear end (right in FIG. 1) of the ram boring device is moved. If the percussion piston 3 has moved sufficiently far to the rear, the control sleeve 6 closes the control openings

7 first and then releases them on the opposite side again, whereby the pressure in the working chamber 8 is released to atmospheric pressure. As a result, the pressure in the inner working chamber 9 exceeds that of the outer working chamber 8, so that the percussion piston 3 moves forward again in the direction of the drill head 2 of the device.

For reversing the direction of movement of flow to return is provided to move the control sleeve 6 within the housing 1 to the rear. As a result, the middle position of the percussion piston 3 is simultaneously offset.

For this purpose, the ram boring device has a guide tube 10, which is connected to the housing 1 and a supply line 14 for the compressed air. The control sleeve 6 is seated axially (in the limits defined by the edges 21) displaceably on the guide tube 10. The arrangement of the edges 21 on the inner circumference of the control sleeve 6 and the outer periphery of the guide tube 10 is achieved that the two components an annular pressure chamber eleventh form, whose size is changed by the relative movement of the components to each other.

A hydraulic line 12 extends within the guide tube 10 and extends into the front region of the device. About a connection (inlet 13) is the

Pressure chamber fed with flushing fluid from the hydraulic line 12.

In the illustrated embodiment, the hydraulic line 12 extends within the compressed air supply 14 and within the guide tube 10. Similarly, it is possible to arrange the hydraulic line 12 wholly or substantially outside the compressed air supply 14 and / or the guide tube 10.

About the pressure in the pressure chamber 11 in conjunction with the back pressure acting on the control sleeve 6 within the inner working space 9, the relative position of the control sleeve 6 in the housing 1 can be changed. In this way, the

Piston stroke and consequently the stroke rate changed and the direction of movement of the ram boring device are reversed.

The hydraulic line 12 extends further through the percussion piston 3, which has corresponding holes, up to the drill head 2 of the device. The illustrated

Embodiment of the drill head 2 represents a multi-stage head. This consists of a chisel 15 with an attached step cone 16. The rear end of the chisel projects to a small extent in the outer working space 8, so that the percussion piston 3 first strikes the chisel 15 and propels it and the step cone 16 into the soil lying in front of the ram boring device , This allows a targeted high introduction of impact energy into the soil.

Only when the rear edge of the bit 15 is in a plane with the impact surface 4, the remaining energy is transferred to the housing, so that it is then moved with the bit 15 and the step cone 16.

The movement that the bit performs relative to the housing 1 of the ram boring device can be allowed by the hydraulic line 12, for example by being designed to be elastic. Another possibility is that the hydraulic line 12 is designed with an excess length which corresponds to the relative movement of the bit 15 in the housing 1.

Within a valve chamber 17 of the chisel 15, a pressure limiting valve 18 is arranged. The pressure relief valve 18 opens at a certain pressure within the hydraulic line 12 and releases a channel 19, which extends longitudinally within the chisel 15 and leads to two outlet openings 20 in the chisel tip. By the

Outlets 20 occurs when the valve 18 is open rinsing fluid under pressure into the soil. The rinsing liquid serves to soften the soil before the step cone 16, so that a better drilling progress can be achieved.

Claims

claims:

1. Rammbohrvorrichtung with a within a housing (1) mounted, driven by a driving pressure gas in a cyclic reciprocating motion percussion piston (3), wherein the percussion piston (3) in a first switching position on a front striking surface (4) impinges on the Rammbohrvorrichtung to drive in a first direction of movement, and in a second switching position on a rear striking surface (5) to drive the ram boring device in a second direction of movement, wherein the switching between the

Movement directions by a displacement of the central position of the percussion piston (3) within the housing (1), characterized in that the displacement of the central position of the percussion piston (3) by a pressurized liquid, which is supplied to the ram boring device independently of the drive compressed air ,

2. Rammbohrvorrichtung according to claim 1, characterized by a housing-fixed guide tube (10), on the guide tube (10) axially displaceable control sleeve (6) and on the control sleeve (6) axially displaceable percussion piston (3), wherein an outer surface of the Guide tube (10) and an inner surface of the control sleeve (6) form a pressure chamber (11) whose size is defined by the relative position of the guide tube (10) and control sleeve (6) to each other.

3. Rammbohrvorrichtung according to claim 2, characterized in that the relative position between the guide tube (10) and the control sleeve (6) by a supply of the pressure fluid to the pressure chamber (11) fixed and can be varied.

4. Rammbohrvorrichtung according to any one of claims 2 or 3, characterized by a hydraulic line (12) for the hydraulic fluid, the inside of the guide tube (10) and the percussion piston (3) extends and up to at least one

The outlet opening (20) for the pressure fluid in the region of a drill head (2) of the ram boring device is sufficient.

5. Rammbohrvorrichtung according to claim 4, characterized by a pressure limiting valve (18) in the hydraulic line (12) between an inlet (13) to the pressure chamber (11) and the outlet opening (20) in the region of the drill head (2).

6. ram boring apparatus according to claim 4 or 5, characterized by a plurality of outlet openings, which are preferably circular in uniform

Division are arranged on the circumference of the drill head.

7. Rammbohrvorrichtung according to claim 6, characterized by means by which the pressure fluid flow can be regulated by the individual outlet openings.

8. A method for operating a ram boring device, wherein a percussion piston (3) within a housing (1) of the ram boring device by means of a driving pressure gas in a cyclic reciprocating motion is driven, wherein the percussion piston (3) in a first switching position on a front striking surface ( 4) to drive the ram boring device in a first direction of travel and in a second switching position to a rear striking surface (5) to drive the ram boring device in a second direction of movement, wherein the switching between the directions of movement by shifting the middle position of the percussion piston (3) takes place within the housing (1), characterized in that the displacement of the central position of the Schlagkclbεπs (3) by a pressure fluid, which is supplied to the ram boring device independently of the drive pressure air.

9. The method according to claim 8, characterized in that the pressure fluid is introduced through at least one outlet opening (20) in the region of a drill head (2) in the soil.

10. The method according to claim 9, characterized in that the pressure fluid is introduced only after exceeding a defined by a pressure relief valve limit value of the pressure in the soil.

11. The method according to claim 9 or 10, characterized in that the pressure fluid for a direction correction is unilaterally out of the Rammbohrvorrich- direction.

12. The method according to any one of claims 9 to 11, characterized in that the introduction of the hydraulic fluid is stopped in the soil in reverse operation of the ram boring apparatus.