GB2066878A

GB2066878A - Apparatus for producing target- directed bores

Info

Publication number: GB2066878A
Application number: GB8100129A
Authority: GB
Original assignee: Bergwerksverband GmbH
Current assignee: Bergwerksverband GmbH
Priority date: 1980-01-05
Filing date: 1981-01-05
Publication date: 1981-07-15
Also published as: AT373358B; AU536279B2; CA1154749A; FR2473105A1; SE8008775L; BR8008612A; CH653406A5; GB2066878B; ATA581A; FR2473105B1; SE441376B; AU6586080A

Abstract

A directable boring bar 1 has an inner rotatable portion 3 and an outer stationary portion 4 mounting inclination meters 14. Control rails 9 extending along the bar 1 are moved outwards by hydraulic rams 10, 11 to control the direction of the bar. Hydraulic pressure and electrical power are generated from the rotation of the inner portion 3. <IMAGE>

Description

SPECIFICATION Apparatus for producing target-directed bores The invention relates to apparatus for producing target-directed bores, in particular boreholes in coal mining, comprising a directable boring bar, which is arranged behind a boring crown in a boring bar assembly. Such apparatus serves to places bores as close as possible to the predetermined target.

Target-directed bores are of particular importance for exploration, supply, or rescue.

It is known to dispose a rigid directable boring bar behind the boring crown for the purpose of stabilisation of the boring bar assembly. These directable boring bars can stabilise only the boring bar assembly, but cannot exclude aberration of the bore. In particular it is impossible to correct with such directable boring bars a gradually occurring deviation from the predetermined boring direction in the course of the boring operation. It is particularly disadvantageous that the deviation which has occurred during the boring operation can be detected accurately only at the target location. Furthermore it has been attempted to make use of more or less automatically operating directable boring bars by means of an oscillatory control.The relatively expensive control may lead to deviations owing to adjustment errors or disturbances in the system, and such deviations can likewise be detected only at the target location or after the termination of the bore. The cause of such defective bores may also be the prevailing inertia range in the system of the oscillatory control.

What is desired is apparatus by means of which the course of the borehole can be controlled as well as corrected.

The present invention provides a directable boring bar which comprises an inner rotatably mounted portion and an outer stationary portion, wherein electrical inclination meters and adjustable pivotally mounted control rails are arranged at or in the outer stationary portion.

A directable boring bar equipped in this manner permits continuous control of the course of the borehole by means of the electrical inclination meters and corresponding correction by means of the control rails, which can be moved out of the outer stationary portion dependently upon the deviation. In this case it is possible to indicate the deviation indicated by the electrical inclination meters by means of measuring cables which extend in the boring assembly as far as a control desk where evaluation is effected and from where appropriate counter-measures are initiated or the appropriate control rails are energised. The supervision and control may be effected section by section advantageously during boring pauses because in these intervals of time vibrations and other sources of error are excluded; however, the measurement and the control may also be performed during boring.

An aberration of the bore is counteracted in an advantageous manner by means of a directable boring bar equipped in this manner wherein the control rails are mounted at the head of the directable boring bar and are pivotal by means of hydraulically loadable cylinders which are arranged in the upper portion of the directable boring bar. In this way the necessary corrections can be performed with the smallest cylinder movements, namely in that the control rails are displaced in the same manner as the umbrella rods of an umbrella. At the same time such a displacement and arrangement of the control rails ensures far-reaching protection of the parts required for the control.

According to one embodiment of the invention the inclination meters are associated with magnetic valves which regulate the supply of the hydraulic cylinders. In this case the magnetic valves are so adjusted that they energise the control rails arranged on the outside in analogous correspondence with the data of the inclination meters. There are preferably, four control rails spaced equally about the boring bar.

For the purposes of supervision and avoidance of erroneous measurements it is convenient to arrange the inclination meters in a cross-wise manner. Faulty measurements can be easily detected thereby from the control desk and excluded by correcting intervention.

The operating pressure required for the hydraulic control is advantageously produced in the directable boring bar itself. For this purpose, an eccentric can be disposed on the rotatably mounted portion of the directable boring bar and the required operating pressure can be produced thereby; at the same time actuation of the cylinders is possible also during boring pauses by means of pressure-limited hydraulic stores which are interposed between the pressure generator and the cylinders.

For the purpose of avoiding a supply cable which is located within the boring assembly, and for producing a sufficient supply tension within the directable boring bar itself, in a further advantageous embodiment, a gearwheel is secured on the shaft of a generator which is connected to the outer stationary portion of the directable boring bar, the gearwheel meshing with a second gearwheel which is fastened on the rotatably mounted portion. Thereby, perfect transmission of the rotary energy is possible, in particular when the second gearwheel is shrunk upon the rotatably mounted portion of the directable boring bar constituting the rotating boring shaft. In order to avoid projecting members, it is preferable in this case to arrange the generator within the stationary portion of the directable boring bar.

A further embodiment of the invention provides that the internal wall of the outer stationary portion of the directable boring bar is constructed as a stator and the surface of the rotatably mounted portion is constructed as a rotor. In this case the stator is preferably formed by a tubular sleeve which is securely connected to the stationary portion, whereas the rotor is formed by permanent magnets which are positively connected to the rotatably mounted portion. Such apparatus is of very small construction and suitable particularly for the envisaged applications.

An important advantage of the invention resides in that off-course travel of a bore can be easily detected by control measures which may be repeated as frequently as may be desired and can be excluded by appropriate corrective measures. Thereby the frequently considerable additional costs and boring times are avoided which are connected with the off-course travel of a bore.

The technical advance of the invention is to be seen in particular in the fact that, by means of such a directable boring bar, automatic correction is possible when deviations from the predetermined boring direction occur, and simultaneously the course of the bore may be controlled from the boring desk.

Furthermore, the measuring and regulating elements arranged in the boring bar can be operated without the supply of additional energy.

The invention will be described further, byway of example, with reference to the accompanying drawings, in which: Figure 1 shows a directable boring bar, partly in axial section; Figure 2 shows part of a directabie boring bar with a control and correction device, in section; and Figure 3 is similar to Figure 2 and shows an alternative embodiment.

As may be seen from the largely diagrammatic illustration according to Figure 1,the directable boring bar 1, which forms part of a boring bar string, consists substantially of an inner rotatably mounted portion 3 and an outer stationary portion 4. A flushing duct 22, by means of which flushing liquid is supplied to the boring crown (not illustrated), leads centrally through the boring bar 1.

At the head 2 of the boring bar 1, control rails 9 are connected to the stationary portion 4 by means of holders 8. The control rails 9 are loadable by rams 10, 11, which are arranged in the upper portion 6 of the boring bar 1,so that upon appropriate loading they move away from the stationary portion 4 in the lower portion 7 of the directable boring bar 1. Their movement is unified by means of path limiters 12.

Springs 13 associated with the path limiters 12 return the control rails 9 to their starting position when the rams 10,11 are rendered free of pressure.

The control of the rams 10,11 is effected by means of magnetic valves 16,17 which in turn are controlled by inclination meters 14. The inclination meters 14 in turn are so connected that the deviations detected by them are simultaneously transmitted to a control desk by a measuring cable 16 or some other means.

The operating pressure required for the hydraulic control is produced by a pressure generator 19 driven by the rotating portion 3 of the boring bar 1 or by an associated eccentric 23. Built-in pressurelimited hydraulic stores 20 permit actuation of the rams 10,11 in the boring pauses, the required liquid being removed from a tank 18 by way of the pressure generator 19.

Current supply for the (electrical) inclination meters 14 and the magnetic valves 16,17 is effected by the cable used simultaneously as measuring and control cable 15, or by other means.

It is possible to couple the inclination meters directly to the respective control rams. In this case, however, visual control from the boring desk cannot be performed without additional expenditure.

Figure 2 illustrates a further possibility to feed the necessary supply voltage to the electrical inclination meters 14andthe magnetic valves 16, 17.A generator 25 is provided for this purpose; in the illustration according to Figure 2 it has been placed upon the outer stationary portion 4 for reasons of simplicity. A gearwheel 27 is mounted on the generator shaft 26 and meshes with a second gearwheel 28 which is, for example, shrunk upon the inner rotatably mounted portion 3 which constitutes the boring shaft. Furthermore it may be envisaged that this gearwheel is formed in the boring shaft, i.e.

in the inner rotatably mounted portion 3, so that the boring shaft itself is not loaded by additional forces.

The casing of the generator 25 is provided with the terminals 29 at which the supply voltage for the consumers, i.e. for the electrical inclination meter 14 and the magnetic valves 16,17 is taken off.

In the embodiment illustrated in Figure 3, the boring bar 1 is so constructed that practically no projecting members of any kind are present. In this case the stator 30 is formed by a tubular sleeve which is securely connected to the stationary portion 4 of the boring bar. The necessary rotor 31 is formed by permanent magnets which are positively connected to the boring shaft, i.e. the inner rotatably mounted portion 3 of the boring bar. The supply voltage needed for the consumers is taken off terminals 32 in this case.

Claims

1. Apparatus for producing target-directed bores, comprising a directable boring bar having an inner portion which is rotatably mounted, and an outer portion which is stationary, inclination meters mounted on the stationary portion, control rails extending along the boring bar, and means for moving the control rails outwards.

2. Apparatus as claimed in claim 1, in which each control rail is pivotally connected at one end to the stationary portion and is pivotable by means of a hydraulic ram to move the rail outwards.

3. Apparatus as claimed in claim 2, in which the said one end is adjacent the leading end of the boring bar, and the ram acts on the leading end part ofthe rail.

4. Apparatus as claimed in any of claims 1 to 3, in which the inclination meters are associated with magnetic valves which control the means for moving the rail.

5. Apparatus as claimed in any of claims 1 to 4, in which the inclination meters are arranged in a cross-wise manner.

6. Apparatus as claimed in any of claims 1 to 5, in which an eccentric is arranged on the rotatably mounted portion of the boring bar.

7. Apparatus as claimed in any of claims 1 to 6, in which pressure-limited hydraulic stores are interposed between a pressure generator and means for moving the rails.

8. Apparatus as claimed in any of claims 1 to 7, in which a dynamo is mounted on the stationary portion of the boring bar, the dynamo being drivable by means of the rotatably mounted portion and supplying batteries or electrical equipment accommodated in the boring bar.

9. Apparatus as claimed in any of claims 1 to 7, in which a gearwheel is secured on the shaft of a generator which is mounted on the stationary portion of the boring bar, the gearwheel meshing with a second gearwheel which is connected to the rotatably mounted portion.

10. Apparatus as claimed in claim 9, in which the second gearwheel is shrunk upon the rotatably mounted portion.

11. Apparatus as claimed in claim 9 or 10, in which the generator is arranged within the stationary portion of the boring bar.

12. Apparatus as claimed in any of claims 1 to 7, in which the stationary portion of the boring bar constitutes a stator and the rotatably mounted portion constitutes a rotor of an electrical generator.

13. Apparatus as claimed in claim 12, in which the stator comprises a tubular sleeve which is securely fastened to the stationary portion and the rotor comprises permanent magnets which are positively connected to the rotatably mounted portion.

14. Apparatus for producing target-directed bores, substantially as described with reference to, and as shown in, Figure 1 of the accompanying drawings.

15. Apparatus as claimed in claim 14, embodied as described with reference to, and as shown in, Figure 2 or Figure 3 of the accompanying drawings.