EP1658415B1

EP1658415B1 - A drilling device with a telescopic arm

Info

Publication number: EP1658415B1
Application number: EP03818412A
Authority: EP
Inventors: Medardo Rioli
Original assignee: Rioli Medardo & C SNC
Current assignee: Rioli Medardo & C SNC
Priority date: 2003-08-28
Filing date: 2003-08-28
Publication date: 2008-04-02
Anticipated expiration: 2023-08-28
Also published as: DE60320151D1; AU2003265152A1; WO2005021927A1; ATE391222T1; EP1658415A1

Abstract

A drilling device with a telescopic arm (2) is described and comprises a drilling member (3) and a drive means (4) with rotor and stator portions for rotating the drilling member (3). The rotor portion of the drive means (4) is connected directly to the drilling member (3) and the stator portion of the drive means (4) is fixed firmly to the telescopic arm (2) so that the drilling member (3) is driven with a rotary motion relative to the arm (2).

Description

Technical field

The present invention relates to a drilling device with a telescopic arm according to the preamble to main Claim 1.

Background art

As is well known, devices of the above-mentioned type are used for earth drilling and boring, particularly in applications in which it is necessary to perform fairly deep earth drilling. They have a drilling member, for example, such as a rotary helicoidal drill bit, supported on a telescopic arm which can be positioned perpendicularly relative to the earth to be drilled. Drive means are provided for rotating the drill bit which is driven deeply into the earth by lengthening of the telescopic arm. The arm is generally also arranged to be mounted on self-propelled transport means such as, for example, tracked or tyred trucks.
A drilling device having the feature outlined above is known from GB 2032494 . In a first known type of these devices, the telescopic elements of the arm are fixed for rotation with the drilling member and are thus rotated by the motor for driving the drill bit. However, this solution requires suitable dimensioning of the telescopic elements which are intended both for transmitting the drive to the drill bit and for withstanding the stresses that are generated during drilling, particularly torsional stresses, so that it is necessary to increase the overall weight and inertia of the telescopic arm.
It is also known to provide the motor for driving the drill bit in a position at the top of the telescopic arm or at least in a position such as to be remote from the location of the drill bit during the extension travel of the arm. A limitation of this application is that the oscillations and vibrations that are produced in the region of the drill bit are transferred directly to the telescopic elements of the arm, to the detriment of the overall reliability of the drilling device. These vibrations may also be amplified along the telescopic extent of the arm, with the risk of compromising the functional capability of the device.

Description of the invention

The problem underlying the present invention is that of providing a drilling device with a telescopic arm which is designed structurally and functionally to provide for a precise regulation of the drilling pressure and to overcome the limitations discussed with reference to the prior art mentioned.
This problem is solved by the invention by means of a drilling device with a telescopic arm formed in accordance with the appended claims.

Brief description of the drawings

The characteristics and the advantages of the invention will become clearer from the following detailed description of a preferred embodiment thereof which is described by way of non-limiting example with reference to the appended drawings, in which:

Figure 1 is a perspective view of a drilling device with a telescopic arm according to the present invention,
Figure 2 is a schematic side elevational view of the device of Figure 1, and
Figure 3 is a partial section through a detail of the device of the preceding drawings.

Preferred embodiment of the invention

With reference to the drawings mentioned, a drilling device with a telescopic arm 2, formed in accordance with the present invention, is generally indicated 1. The device 1 has a drilling member such as a drill bit 3 with a helicoidal profile which can be rotated about its principal axis X by a motor 4, preferably of the hydraulically operating type.
According to a principal characteristic of the invention, the motor 4 is operatively connected to the drill bit 3 by a direct connection. In greater detail, the motor 4 is connected to the drill bit coaxially at an axial end 4a of the motor remote from the end 4b for coupling to the telescopic arm. The motor 4 has conventional rotor and stator portions. The rotor portion is connected to the drill bit 3 and the stator portion is fixed firmly to a casing 5 at least partially housing the motor 4. The casing 5 is provided with a pin-like portion 6 for the articulated coupling of the motor to the telescopic arm in the region of the end 4b.
The arm 2 comprises a plurality of elements 7 which are connected telescopically for sliding inside one another from the innermost element, indicated 7a for greater clarity, to the outermost element, indicated 7b. Naturally, the number of telescopic elements (seven of which are shown in the drawings) may vary according to the specific applications for which the device is intended, in dependence on the required degree of extension of the arm 2. A preferred selection provides for the telescopic arm 2 to have a minimum axial length of about 3.5 metres with the elements 7 in the contracted position and a maximum axial length of about 20 metres after the telescopic elements 7 have been fully extended.
The elements 7 are guided for sliding in one another and have a hollow tubular configuration with a thin, preferably square cross-section. Alternatively, the cross-section may be circular or of another polygonal shape, provided that the mutual concentricity of the telescopic elements 7 is maintained. It should be noted that, in the operative position of Figure 2, with the arm supported in a vertical position relative to the ground T, the arm 2, the motor 4, and the drill bit 3 are aligned coaxially in that vertical direction, in positions adjacent one another.
Cable extraction means for the telescopic elements 7 which can bring about the extension of the arm 2 are generally indicated 8. These means comprise at least one pair of cables 9, which are advantageously steel-wire cables (only one of which is visible in the schematic view of Figure 3), and each of which has an end 9a fixed to the innermost telescopic element 7a. Starting from this end 9a, each cable is caused to slide over a first longitudinal side of the telescopic element and is returned, by means of a pair of guide wheels 10, over the second, opposite longitudinal side of the element until it is returned again (through about 180?), by means of a wheel 11, towards the adjacent telescopic element 7. This guide and return configuration of each cable 9 is repeated in the telescopic elements until a guide 12 on the outermost element 7b is reached; a final portion of the cable 13 extends from this guide 12 and the free end 9b of the cable 13 is restrained on the surface of a winding drum 14 of a winch 15. The winch 15 is fixed to one of the sides of the outermost telescopic element 7b. As a result of the winding of the cables 9 onto the winch 15, each telescopic element 7 is extracted from the element adjacent thereto, as shown schematically in Figure 3, so as to bring about extension of the arm 2.
Similarly, cable retraction means 16 for the telescopic elements of the arm 2 are provided in the device of the invention for returning the arm to a contracted condition of minimum axial extent, as shown in Figure 2. The retraction means 16 comprise at least one cable 17, which is advantageously of the steel wire type and which has an end 17a that is fixed to the innermost telescopic element 7a of the arm. From this end, the cable 17 extends coaxially inside the telescopic elements until it emerges from the outermost element 7b where it is returned by means of a guide wheel 18 towards a winding drum 19 of a respective winch 20 on which the free end of the cable 17b is secured. As a result of the winding of the cable 17 onto the winch 20, the telescopic elements 7 are thus slid back to the contracted position inside one another, as can clearly be seen from the diagram of Figure 3. In the fully retracted position, the arm 2 adopts the configuration of lesser axial extent.
It is pointed out that, during the extension travel of the arm, the cable extraction means 8 exert a thrust on each element 7 with a reduction effect of the tension on the cable due to the presence of the guide wheels 10 and 11. In the vertical working position relative to the earth, the tensile stress produced in the cables 9 also permits the exertion of a constant arm-lengthening pressure which is therefore not due exclusively to the weight of the arm itself as in conventional devices. Similarly, during the retraction travel, the tension produced in the cable 17 is such as to urge the telescopic elements vertically upwards (in the working position), exerting a counter-pressure which can be kept constant, irrespective of the weight of the arm itself. In some applications it is also possible to exert pressures during drilling which are less than those due to the weight of the device itself, resulting in greater degree of reliability and safety.
The balancing of the lengthening and contracting stresses, so as to produce constant pressures ensures a very efficient vertical shock-absorbing system. In greater detail, the system of winding cables is effective in damping the vibrations that are generated by the drill bit in an axial direction whilst the telescopic system with concentric tubular elements is effective in damping the vibrations that are generated by the drill bit in directions transverse its axis of rotation.
With specific reference to Figure 2, it is also pointed out that the projection, along the axis (X) of the axial extent of the arm, of the overall dimensions of the motor 4 and of the telescopic arm 2 is included within the projection along the same axis of the overall dimensions of the drill bit 3, with the advantage that all of the members of the device can enter the hole in the ground T produced by the drill bit 3.
For precise regulation of the drilling pressure, a pair of hydraulically-operated jacks 21 is provided; the jacks 21 have axially opposed operative ends 21a, 21b which are restrained on the outermost telescopic element 7b and on a connection element 22 slidably associated with the element 7b, respectively. In greater detail, the connection element 22 comprises a tubular body 23 which is fitted slidably on the element 7b of the arm 2 and which is provided with eye (or pin) portions 24 for the articulated coupling of the telescopic arm 2. This articulated connection enables the arm 2 to be coupled to an arm 25 of a self-propelled machine or other structure supporting the device, a chassis portion 26 of which is shown schematically in Figure 2.
In operation, the arm 2 is first of all positioned vertically relative to the ground T with the axis X of the drill bit substantially perpendicular to the ground. The drill bit 3 is rotated about its own axis X by means of the motor 4 and the arm 2 is lengthened by the extraction of the telescopic elements 7 in order to follow the depth of the drill bit 3 during the earth-drilling stage. It should be noted that, during the drilling stage, the hydraulic-piston jacks 21 enable the drilling pressure to be regulated precisely whilst the cable extraction and retraction systems 8 and 16 serve to ensure relative locking between the telescopic elements 7 in the arm-extension position reached.
The invention thus solves the problem posed, affording many advantages over known solutions.
A first advantage is that, by virtue of the provision of a direct connection of the drive motor to the drilling member in accordance with the invention, all of the oscillations and vibrations that are generated during the working movement of the drill are absorbed directly by the motor without being transferred to the elements of the arm, resulting in reduced oscillation amplitude for improved operating reliability and safety. The fact that all of the vibrations can be concentrated and localized in the motor also leads to greater overall reliability of the system.
Another advantage is that, by virtue of the above-mentioned positioning of the motor directly connected to the drilling member, the telescopic elements of the arm are not subject to rotation and have the task exclusively of ensuring the positioning of the motor/drill bit assembly. As a result, these elements can advantageously be made lighter than in known solutions, with the use of tubular sections of reduced thickness for a marked overall lightness of the device with equally clear constructional simplifications.
Yet another advantage is that, the overall lightness which can be achieved in the device of the invention allows the device to be coupled to the working arms of conventional self-propelled machines such as, for example, excavators and the like. The low weight of the device enables the cantilevered coupling distances provided for in conventional operating machines to be utilized without compromising their stability and also renders the device adaptable to support arms of conventional excavators, thus increasing the versatility of the device.

Claims

A drilling device for earth drilling comprising:
- a telescopic arm (2) with a plurality of elements (7) connected to one another telescopically,

- a drilling member (3) and

- a drive means (4) with rotor and stator portions for rotating the drilling member (3), the rotor portion of the drive means (4) being connected directly to the drilling member (3),

- the drive means comprising a motor with the stator portion of the motor (4) fixed firmly to the telescopic arm (2) so that the drilling member (3) is driven with a rotary motion relative to the arm (2), and

- cable extraction means (8) provided between the elements (7) for the lengthening of the telescopic arm (2), and

- separate cable retraction means (16) for the elements (7) of the arm (2) for bringing the arm (2) to a contracted position of minimum axial extent, characterized in further comprising:
- means, acting on the drilling member (3), for regulating the drilling pressure, said regulating means comprising at least one pair of hydraulically-operated jacks (21) each of which has opposed operative axial ends (21a, 21b) that are restrained on the outermost element (7b) of the tubular arm and on a connection element (22) slidably associated with the outermost telescopic element (7b), respectively, the connection element (22) constituting means for the coupling of the telescopic arm (2) to a respective arm (25) of a self-propelled machine of other structure supporting the drilling device (1).
A device according to Claim 1 in which the motor (4) is supported on the arm (2) in the region of an axial end of the arm at the end remote from the connection of the motor (4) to the drilling member (3).
A device according to Claim 1 or Claim 2, in which the drilling member (3), the motor (4), and the arm (2) are mutually aligned in positions adjacent one another.
A device according to one or more of the preceding claims in which said plurality of elements (7) extend coaxially with the motor (4) and with the drilling member (3).
A device according to one or more of the preceding claims in which the projection, along the axis (X) of axial extent of the arm, of the overall dimensions of the motor (4) and of the telescopic arm (2) is included within the projection along that axial axis of the overall dimensions of the drilling member (3).
A device according to Claim 4 in which the elements (7) have a concentric tubular configuration.
A device according to Claim 1, in which the extraction means (8) comprise at least one first cable (9) fixed by one (9a) of its ends to the innermost element (7a) of the telescopic arm (2) and having its opposite end (9b) connected to a winding drum (14) of a respective first winch device (15) which is restrained on the outermost telescopic element (7b) of the arm, the at least one first cable (9) being guided between adjacent pairs of elements of the arm (2) so that, as a result of the winding of the cable onto the winch, each element (7) is extracted from the element adjacent thereto in order consequently to bring about extension of the telescopic arm (2).
A device according to Claim 1, in which the retraction means (16) comprise at least one second cable (17) which is fixed by one end (17a) to the innermost telescopic element (7a) of the arm (2) and extends inside the telescopic elements, its other end (17b) being connected to a corresponding winding drum (19) of a second winch device (20) which is restrained on the outermost telescopic element (7b) of the arm, so that, as a result of the winding of the cable (17) onto the winch (20), the telescopic elements are slid back to the contracted position inside one another for the retraction of the telescopic arm (2).
A device according to Claim 6 in which the concentric tubular elements (7) of the telescopic arm (2) have thin circular or polygonal cross-sections.
A device according to one or more of the preceding claims, in which the connection element (22) comprises a tubular body (23) fitted slidably on the outermost telescopic element (7b) of the arm and carrying eyes (24) for the articulated coupling of the telescopic arm (2).