METHOD AND APPARATUS FOR OPERATING AN ACTUATOR
A drilling or flushing medium is used in the operation of an actuator for controlling an earth working device which uses the drilling or flushing medium for its operation as well. The actuator is acted upon by the medium , which can be retained in the actuator through suitable operation of a valve assembly, while at the same time can be supplied to the earth working device to execute a desired function. The valve assembly is hereby actuated by a separate switch.
Latest Tracto-Technik GmbH & Co. KG Patents:
This application claims the priority of German Patent Application, Serial No. 10 2006 016 613.2, filed Apr. 6, 2006, pursuant to 35 U.S.C. 119(a)-(d), the content of which is incorporated herein by reference in its entirety as if fully set forth herein.
BACKGROUND OF THE INVENTIONThe present invention relates to a method for operating an actuator, and apparatus for carrying out the method.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
Earth boring and laying of pipelines in the ground involves the use of tools or drill heads which can be controlled in various ways. Examples include the use of asymmetric drill heads which can be adjusted through turning at the hose, or a control of the head by means of an asymmetric jet of drilling liquid issuing out of the drill head. Control of the drill head may hereby serve for targeted change in the drill course or also to only compensate for variations in soil conditions. Conventional approaches, which use actuators in the area of the drill head or other equipment elements that are difficult to access in the ground, have all the basic problem that any control of the actuators, which are also situated inaccessibly in the ground, has to be carried out from ground level, e.g. using mechanical systems, electrical auxiliary lines, wireless communication, or a pressure medium source.
However, for a number of reasons, the various proposals are endowed with drawbacks and shortcomings relating to the effect that is hoped to be obtained but may not always be realized. For example, purely mechanical solutions oftentimes are difficult to operate in view of the conditions on the construction site and the forces and frictions caused during drilling.
There is a special need for the precise control to realize a compensation control for maintaining a straight drilling course in the ground, when laying sewage lines at slight gradient is involved, which are operated solely by the force of gravity. This requires high precision, in particular for the installed depth, because excessive deviations may result in deposits or clogging of the sewage pipe during later operation. Difficulties arose when installing lines into the ground because of the inability to install them in a sufficiently straight manner along the intended path. The vertical and horizontal rectilinearity always fluctuates more or less. These fluctuations oftentimes exceed the admissible tolerances, in particular when sewage lines are involved in very flat terrain, so that the installation using current horizontal drilling technique caused problems.
Known methods (open construction, auger equipments, etc.) operate very slowly. Open construction may damage in some circumstances high-quality surfaces which require repair after installation. Respective methods are known from WO 02/057590 A2, U.S. Pat. No. 6,668,946 B2, DE 196 05 983 C2, and DE 198 02 209 C2.
It would therefore be desirable and advantageous to provide an improved method and apparatus for operating an actuator to obviate prior art shortcomings.
SUMMARY OF THE INVENTIONAccording to one aspect of the present invention, a drilling or flushing medium is used in the operation of an actuator for controlling an earth working device.
According to another aspect of the present invention, an apparatus includes at least one actuator for controlling an earth working device, and a valve assembly for operating the actuator by means of a drilling or flushing medium.
The present invention resolves prior art problems by implementing an adjustment of the actuator (e.g. lift pad, cylinder, etc.) by the potential energy (pressure energy) of the provided drilling medium (e.g. bentonite). As a consequence, the actuator can be operated inside a drilling tool or expansion tool in the absence of any supply of separate control means (like e.g. electric energy or hydraulic pressure). The use of respective feed lines may also be omitted because the use of the drilling liquid, which exists anyway, as control means eliminates the need for additional supply lines and/or control lines which would have to be conjointly routed e.g. from drill rod section to drill rod section and respectively connected. Liquids that pose a hazard to the environment, like e.g. hydraulic oil, are not necessary so that a risk of soil contamination is avoided.
According to another feature of the present invention, the valve assembly may include a camshaft, and plural valves which are operated by the camshaft. Suitably, the valve assembly includes a cylinder which is operated by the fluid and operatively connected to the camshaft.
According to another feature of the present invention, the actuator may be configured as lift pad.
According to another feature of the present invention, the earth working device is constructed for advancing along a predefined drilling route, wherein a tool can be provided for correcting an advance of the earth working device to compensate for a deviation from the drilling course. Thus, the tool is able to correct any fluctuations of the drilling course in the absence of a separate supply of electric current or other control means.
According to another feature of the present invention, the valves may be spring-biased valves.
According to another feature of the present invention, the apparatus is suitable for carrying out any one of the operations selected from the group consisting of correcting a deviation of a drill head in a pilot bore, when the earth working machine is the drill head, correcting a deviation of an expansion head, when the earth working machine is the expansion head and lines are pulled in, opening and closing of valves or gates, operation of borehole tools, disengagement or engagement of tools in the ground, and moving out of a bore route for establishing branch lines or for exploration.
According to another aspect of the present invention, a method for operating an actuator for controlling an earth working device includes the steps of subjecting the actuator to a drilling or flushing medium used for the earth working device, and controlling an operation of a valve assembly such that the drilling or flushing medium is retained in the actuator, while at the same time is supplied to the earth working device for executing a desired operation.
According to another feature of the present invention, the controlling step can be realized by actuating a separate switch for adjusting the operation of the valve assembly.
According to another feature of the present invention, the valve assembly may include plural spring-biased valves which return to their initial position when a pressure of the drilling or flushing medium drops below a spring force which acts on the valves.
BRIEF DESCRIPTION OF THE DRAWINGOther features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which.
Throughout all the Figures, same or corresponding elements are generally indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments are sometimes illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.
Turning now to the drawing, and in particular to
In
While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. The embodiments were chosen and described in order to best explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and includes equivalents of the elements recited therein:
Claims
1. A drilling or flushing medium for use in the operation of an actuator for controlling an earth working device.
2. Apparatus, comprising:
- at least one actuator for controlling an earth working device; and
- a valve assembly for operating the actuator by means of a fluid selected from the group consisting of drilling medium and flushing medium.
3. The apparatus of claim 2, wherein the valve assembly includes a camshaft, and plural valves which are operated by the camshaft.
4. The apparatus of claim 3, wherein the valve assembly includes a cylinder which is operated by the fluid and operatively connected to the camshaft.
5. The apparatus of claim 2, wherein the actuator is configured as lift pad.
6. The apparatus of claim 2, wherein the earth working device is constructed for advancing along a predefined drilling route, and further comprising a tool for correcting an advance of the earth working device to compensate for a deviation from the drilling course.
7. The apparatus of claim 3, wherein the valves are spring-biased valves.
8. The apparatus of claim 2, wherein the fluid is bentonite.
9. The apparatus of claim 2 for carrying out any one of the operations selected from the group consisting of correcting a deviation of a drill head in a pilot bore, when the earth working machine is the drill head, correcting a deviation of an expansion head, when the earth working machine is the expansion head and lines are pulled in, opening and closing of valves or gates, operation of borehole tools, disengagement or engagement of tools in the ground, and moving out of a bore route for establishing branch lines or for exploration.
10. A method for operating an actuator for controlling an earth working device, comprising the steps of:
- subjecting the actuator to a fluid selected from the group consisting of drilling medium and flushing medium and used as the fluid for the earth working device; and
- controlling an operation of a valve assembly such that the drilling or flushing medium is retained in the actuator, while at the same time is supplied to the earth working device for executing a desired operation.
11. The method of claim 10, wherein the earth working device is a drill head or expansion head.
12. The method of claim 10, wherein the controlling step includes the step of actuating a separate switch for adjusting the operation of the valve assembly.
13. The method of claim 10, wherein the valve assembly includes plural spring-biased valves which return to their initial position when a pressure of the drilling or flushing medium drops below a spring force which acts on the valves.
Type: Application
Filed: Apr 5, 2007
Publication Date: Oct 18, 2007
Applicant: Tracto-Technik GmbH & Co. KG (Lennestadt)
Inventor: MANFRED SCHAUERTE (Schmallenberg)
Application Number: 11/696,983
International Classification: E21B 7/04 (20060101);