Driving head for telescopic drill rods and machine comprising said head

Abstract

A driving head for telescopic drill rods has a frame, a cylindrical collar rotatably coupled with said frame, and provided at least with one internal surface comprising at least one driving rack adapted to be coupled with corresponding driven racks of telescopic drill rods, and actuation means to drive said cylindrical collar into rotation, said driving rack being coupled with said cylindrical collar by means of removable connection means. A machine provided with said driving head is also disclosed.

Claims

1. A driving head for a telescopic drill rod, the driving head comprising: a frame; a cylindrical collar rotatably coupled to said frame; and an actuator cooperative with said cylindrical collar so as to drive said cylindrical collar into rotation, said cylindrical collar having at least one internal surface having at least one driving rack adapted to be coupled to corresponding driven racks of the telescopic drill rod, the driving rack being coupled to said cylindrical collar by a removable connector, said removable connector comprising: a threaded hole formed in the internal surface of said cylindrical collar; a housing positioned in the driving rack; and a bolt with an enlarged head adapted to be screwed into said threaded hole and passing through said housing so as to engage the driving rack.

2. The driving head of said claim 1, said housing comprising a first section with a first diameter that is open on one side of the driving rack so as to face the internal surface of said cylindrical collar and a second section with a second diameter that is open on another side of the driving rack which is opposite to the one side facing said internal surface of said collar, the second diameter being greater than the first diameter and less than a diameter of said enlarged head of said bolt.

3. The driving head of said claim 1, the driving rack having a plurality of adjacent teeth, the removable connector being disposed so as to correspond with said plurality of adjacent teeth.

4. The driving head of said claim 3, the teeth of said plurality of adjacent teeth being separated by valleys, said removable connector comprising a first row of removable connectors linearly disposed proximal to said plurality of adjacent teeth and a second row of removable connectors linearly disposed distal to said plurality of adjacent teeth and in correspondence to the valley between a pair of the adjacent teeth.

5. The driving head of claim 1, the driving rack having teeth provided with at least one intermediate section that extends orthogonally to an axis of rotation of said cylindrical collar.

6. A machine having the driving head of claim 1.

7. The machine of claim 6, further comprising: a rectilinear track to which said frame of the driving head is slidably coupled; and a driver slidably activating said frame along said rectilinear track.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) For explanatory reasons, the description of the invention continues with reference to attached drawings, which only have an illustrative, not limiting value, wherein:

(2) FIG. 1 is a perspective view of a driving head according to the present invention;

(3) FIG. 2 is a machine provided with the head of FIG. 1;

(4) FIG. 3 is a detail of a rack section of the head of FIG. 1;

(5) FIG. 4 is a partial cross-sectional view of the head of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

(6) Referring to FIGS. 1 and 2, a driving head (1) for telescopic drill rods (A) comprises a frame (2) and a cylindrical collar (3) rotatably coupled with said frame (2).

(7) The cylindrical collar (3) is provided at least with one internal surface from which at least one driving rack (5) protrudes, being adapted to be coupled with corresponding driven racks of telescopic drill rods (A). The driven racks are realized according to the precepts of the European patent application EP 0 335 059.

(8) Likewise, the driving racks (5) have a complementary shape with respect to the driven racks and are therefore provided with teeth (50) with at least one intermediate section extending in orthogonal direction to the axis of rotation, as shown in FIG. 3.

(9) Generally speaking, the precepts of the present invention may be used regardless of the shape of the tooth (50), which might simply have a wedge-like shape (without the aforesaid intermediate section). However, the best advantages are found in this application, which must be considered as preferential.

(10) The collar (3) is driven into rotation around its axis with actuation means (4) that are preferably hydraulic actuation means.

(11) In some embodiments, the actuation means (4) are associated with the frame (2) and also comprise hydraulic engines to transmit the angular momentum to the collar (3). According to other embodiments, the actuation means (4) are kinematic mechanisms that transmit the angular momentum to the collar (3), whereas the engines are housed on the machine (10).

(12) The frame (2) is slidingly coupled with a rectilinear track (12) to determine a linear movement of said actuation head (1) along the direction of the track (12) parallel to the axis of rotation of the collar (3) to transmit an axial force, either a thrust force or a traction force, to the rods (A), according to the specific requirements.

(13) The movement of the frame (2) along the track (12) is controlled by driving means (13), for example hydraulic cylinders.

(14) Going back to the driving rack (5), as shown in the example, the collar (3) has a plurality of racks (5) protruding from its internal surface.

(15) The number and angular position of said driving racks (5) vary according to the needs and can be chosen by the expert of the field without any inventive effort.

(16) Each driving rack (5) is coupled with the cylindrical collar (3) by means of removable connection means (6) that consist in screw connection means in the embodiment shown.

(17) Moreover, mechanical centering means are provided, between rack and collar, thus contributing to withstand the existing forces.

(18) Now referring to FIG. 4, the removable screw connection means (6) comprise a threaded hole (60) obtained on the internal side of said collar (3), a housing (61) obtained in said driving rack (5), a bolt (62) with enlarged head adapted to be screwed into said threaded hole (60) and passing through said housing (61) to engage said driving rack (5).

(19) More specifically, the housing (61) comprises a first section (61A) with first diameter that is open on one side of said driving rack (5) facing the internal surface of said collar (3).

(20) Moreover, the housing (61) comprises a second section (61B) with second diameter that is open on one side of the driving rack (5) opposite to the side facing said internal surface of the collar (3).

(21) The second diameter is at the same time higher than the first diameter and lower than the diameter of said enlarged head of said bolt (62), in such manner to obtain coupling by interference of shape, which is simple to realize and assemble.

(22) In order to improve the mechanical resistance properties of the coupling between driving rack (5) and collar (3), given the existing forces, the removable connection means (6) are disposed at least in correspondence of the teeth (50) of each rack (5), as shown in FIG. 3.

(23) Another advantageous characteristic in terms of sturdiness derives from the fact that a first (6A) and a second (6B) row of removable connection means (6) are provided.

(24) For each row (6A, 6B) connection means (6) are disposed linearly.

(25) A first row (6A) is in proximal position to the teeth (50) and is provided, with a removable connection means (6) in correspondence with each tooth (50).

(26) Instead, the second row (6B) of removable connection means (6) is disposed in remote position to said teeth (50) and provided with a removable connection means (6) in correspondence of each valley between two adjacent teeth (50).

(27) According to another embodiment, not shown in the attached figures, a stud-bolt is provided instead of the bolt (62), protruding from the internal surface of the collar and being inserted into the hole (61) to lock the driving rack (5) with a nut.

(28) The operation principle and the spatial disposition of the removable screw connection means are similar to the ones described above, therefore omitting a detailed description.

(29) According to another embodiment (not shown in the attached figures), the removable connection means are bayonet connection means, and not screw connection means, for instance with pins adapted to fix each driving rack (5) to the collar (3). In such a case, the pins are inserted by interference in the hole (60) of the collar (3) and engage the rack (5) in the same way.

(30) Such a solution can be advantageously used because, during the various operating conditions, the pins are only subject to cutting forces, and not to a force along their extraction direction.

(31) Moreover, another advantage of such a solution is that it is easy to install, although if additional difficulties are encountered to extract the pins with a suitable puller.

(32) Furthermore, many additional variants are possible within the reach of an expert of the field in the light of the precepts herein disclosed, which are therefore to be considered as an integral part of the present invention.