Percussion boring device and method for reversing a percussion boring device

Patent metadata

Field	Value
Publication number	US-11634949-B2
Application number	US-201615197313-A
Country	US
Kind code	B2
Filing date	Jun 29, 2016
Priority date	Jul 1, 2015
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

A percussion boring device comprising a casing, a guide tube fixed to the casing, and a control bushing axially displaceable on the guide tube. An impact piston of the device is axially displaceable on the control bushing and configured to be actuated in a reciprocating manner within the casing such that in a first switching position the impact piston strikes a front impact surface to actuate the percussion boring device in a first movement direction, and in a second switching position a rear impact surface to actuate the percussion boring device in a second movement direction. A pressure increasing means is provided and configured to generate a pressure for reversing the percussion bore device, wherein the generated pressure is higher than a pressure for moving the impact piston. The guide tube and the control bushing are configured to reverse movement directions of the impact piston.

First claim

The invention claimed is:

1. A percussion boring device comprising:
a casing;
a guide tube fixed to the casing;
an impact piston configured to be actuated in a reciprocating manner within the casing by application of an operating pressure;
a control bushing axially displaceable on the guide tube to (i) a first switching position to actuate the percussion boring device in a first movement direction in which the impact piston strikes a front impact surface, and to (ii) a second switching position to actuate the percussion boring device in a second movement direction in which the impact piston strikes a rear impact surface, wherein the impact piston is axially displaceable on the control bushing;
a control pressure source fluidly coupled to the control bushing and configured to generate a high fluid pressure for axially displacing the control bushing to the first switching position to actuate the percussion boring device in the first movement direction, the high fluid pressure generated being higher than the operating pressure for moving the impact piston in the reciprocating manner in the first movement direction and the second movement direction, and
a control valve configured to cause a pressure in a control pressure line to be reduced below the operating pressure to cause the operating pressure to displace the control bushing to the second switching position to actuate the percussion boring device in the second movement direction;
wherein, while the high fluid pressure for axially displacing the control bushing to the first switching position is applied to the control bushing, the control bushing is in the first switching position and the impact piston is configured to be moved by the operating pressure in the first movement direction;
wherein, while a pressure less than the operating pressure is applied to the control bushing, and the operating pressure is provided to the impact piston, the control bushing is in the second switching position and the impact piston is configured to be actuated by the operating pressure in the reciprocating manner in the second movement direction.

2. The percussion boring device according to claim 1 , wherein an annular space is formed between the guide tube and an annular element, wherein the annular space is at least partially covered by the control bushing, and wherein the annular space is connected to a control line configured to receive the high fluid pressure generated by the control pressure source for axially displacing the control bushing to the first switching position to actuate the percussion boring device in the first movement direction.

3. The percussion boring device according to claim 1 , wherein, for axially displacing the control bushing to the first switching position to actuate the percussion boring device in the first movement direction, the high fluid pressure generated by the control pressure source is 5 to 25 bar.

4. The percussion boring device according to claim 1 , wherein the control valve comprises a multi-position directional control valve which includes at least one position configured to apply the high fluid pressure generated by the control pressure source to the control bushing for axially displacing the control bushing to the first switching position to actuate the percussion boring device in the first movement direction and a second position configured to vent the control pressure line to cause the operating pressure to displace the control bushing to the second switching position to actuate the percussion boring device in the second movement direction.

5. The percussion boring device according to claim 1 , further comprising a pressure reducing valve, wherein the control pressure source is connected to the impact piston and the pressure reducing valve is connected between the control pressure source and the impact piston.

6. The percussion boring device according to claim 1 , wherein operation of the percussion boring device in the first movement direction is based upon applying the high fluid pressure from the control pressure source to axially displace the control bushing to the first switching position for movement in the first movement direction; and
application of the operating pressure to the impact piston for actuation of the impact piston in the reciprocating manner within the casing of the percussion boring device in the first movement direction.

7. A percussion boring device comprising:
a casing;
a guide tube fixed to the casing;
an impact piston configured to be actuated in a reciprocating manner within the casing;
a control bushing axially displaceable on the guide tube to (i) a first switching position to actuate the percussion boring device in a first movement direction in which the impact piston strikes a front impact surface, and to (ii) a second switching position to actuate the percussion boring device in a second movement direction in which the impact piston to strike a rear impact surface, wherein the impact piston is also axially displaceable on the control bushing;
a control line operatively coupled to the control bushing, and a control valve;
a control pressure source, in fluid communication with the control valve, operative to generate a high fluid pressure for axially displacing the control bushing to the first switching position for movement of the percussion boring device in the first movement direction, the high fluid pressure generated by the control pressure source being higher than an operating pressure for actuating the impact piston in the reciprocating manner in the first movement direction and the second movement direction; and
wherein the control valve in a first position is operative to apply a pressure lower than the operating pressure to the control bushing to place the control bushing in the second switching position for movement of the percussion boring device in the second movement direction, and
wherein the control valve in a second position is operative to apply the high fluid pressure from the control pressure source to place the control bushing in the first switching position for movement of the percussion boring device in the first movement direction.

8. The percussion boring device according to claim 7 , wherein an annular space formed between the guide tube and an annular element, wherein the annular space is at least partially covered by the control bushing, and wherein the annular space is connected to the control line and is configured to receive the high fluid pressure for axially displacing the control bushing to the first switching position for movement of the percussion boring device in the first movement direction.

9. The percussion boring device according to claim 7 , wherein, for axially displacing the control bushing to the first switching position to actuate the percussion boring device in the first movement direction, the high fluid pressure generated by the control pressure source is 5 to 25 bar.

10. The percussion boring device according to claim 7 , wherein operation of the percussion boring device in the first movement direction is based upon application of the high fluid pressure from the control pressure source to axially displace the control bushing to the first switching position for operation in the first movement direction, and
application of the operating pressure to the impact piston for movement of the percussion boring device in the first movement direction.

11. A method for operating a percussion boring device including an impact piston in a forward movement direction and a reverse movement direction, the forward movement direction configured to strike a front impact surface to actuate the percussion boring device and the reverse movement directio

Assignees

• Tracto Technik

Inventors

• Völkel Gerhard
• Balve Gerhard

Classifications

• E21B4/145 Primary

  of the self propelled-type, e.g. with a reverse mode to retract the device from the hole · CPC title