Horizontal drilling machine, drilling tool and corresponding drilling method

Abstract

Horizontal drilling machine (10) comprising a support frame (11) on which a drawing member (12) is disposed sliding configured to be selectively moved along a drilling axis (X), and a plurality of drilling tools (13) each having at least one central body (32) provided with a first threaded end (33) configured at least to cooperate with the drawing member (12) and with a second threaded end (34) opposite the first threaded end (33).

Description

FIELD OF THE INVENTION

[0001] The present invention concerns a drilling machine for the horizontal and directional drilling of terrains and, more generally, of mineral strata, also known as a drilling rig or horizontal directional drill, which allows to install new pipelines without having to perform open-pit excavations by first making a pilot hole, either linear or with curved segments, from which to subsequently carry out a widening up to a desired size.

[0002] The present invention also concerns a drilling tool, or rod, usable at least for making the pilot hole, and the corresponding drilling method.BACKGROUND OF THE INVENTION

[0003] Horizontal drilling machines used, for example, to prepare holes for the housing and passage of pipelines under roads, rivers and other infrastructure, are known.

[0004] It is known that these machines provide a support structure installable on the ground in a desired horizontal drilling condition, or inclined with respect to the horizontal, and on which a drawing head, or slider, slides, which is designed to move selectively in a direction longitudinal to the hole to be made.

[0005] A plurality of dimensional series of drilling tools, known as rods, which have an oblong tubular shape of a desired diameter, with male and female threaded ends for their screw-in coupling, are also part of known machines.

[0006] The rods are progressively coupled to the drilling head which, by means of the selective movement in a direction longitudinal to the hole provided, progressively thrusts the rods into the ground, stepwise.

[0007] In this way, once a first rod is inserted into the ground, the head is released, returning to its starting position. In this condition, a new rod is associated with the head and thrust by the latter until it comes into contact with the one previously manipulated. The two rods are screwed together and thrust further into the ground, progressively forming a rod string, into which a desired drilling fluid is introduced under pressure. The return cycle is repeated until the desired excavation depth is reached.

[0008] A first drawback of known machines is that the association between the head and each rod occurs by reciprocal screwing, using the male thread provided at one end of the rod. However, this solution is problematic both in the coupling step and also in the decoupling step, for example, between the conclusion of the operating steps for making the pilot hole and the beginning of the steps for enlarging the hole.

[0009] In fact, the screwing is done manually, requiring good skills to axially align the rod in order to guarantee a correct grip of the threads that, otherwise, may not guarantee a correct connection, even becoming partly compromised, especially the moment in which the head makes the rod rotate in order to screw it to the previous rod.

[0010] When performing this type of manual operations, the weight of the rod and the operating conditions, which can be uncomfortable, must also be taken into account; therefore, it is not always simple and immediate to find the correct alignment, increasing operating times, the risk of errors and malfunctions, with an increase in costs and maintenance times for the machine, as well as a reduction in the latter's productivity.

[0011] In the same way, even the unscrewing of the rod from the head, both in the conditions of release for the manipulation of a subsequent rod, and also in the operations for removing the rods to be replaced, involves complications linked, above all, to the need to guarantee that there is unscrewing only between head and rod, without intervening in the threaded couplings between the other rods. Moreover, since this operation is normally performed automatically by the head, the problem of guaranteeing the unscrewing of only the desired coupling is even more complex.

[0012] In this sense, drilling machines are known that provide a pair of locking jaws, disposed in sequence, a first one, the pack of rods exiting the machine and, a second one closer to the head, only the rod associated with the head itself.

[0013] This known solution is particularly complex for the operating context in which it is provided, since it requires specific automation as well as the provision of double operating equipment, both mechanical and hydraulic, for its operation.

[0014] These aspects have repercussions, consequently, both in the management and maintenance costs, and also in the overall dimensions of the machine which, since it is applied on construction sites that are not always easily accessible, can be difficult to position.

[0015] In addition, these known machines require an intervention of the operator with the machine in motion, to the detriment, mainly, of the work safety conditions and, secondly, of the automation of the entire process.

[0016] US-A-2013 / 277118 discloses a horizontal drilling machine of the suspended type, that is, having a vertically oriented support frame, and comprising a drilling tool manipulation element located in a lower part of the machine, located underground. This entails the disadvantage of allowing the insertion of drilling tools of reduced length, which have to be able to enter horizontally into the internal volume of the machine. In addition, to reduce the overall dimensions of the machine, the manipulation element comprises a seating configured to interact with the drilling tools, but located inside the manipulation element. The drilling tools also have two ends, each of which has a pair of opposing slits for the insertion of a locking fork. It can be deduced that the machine has to be set up precisely, so that the drilling tools are positioned exactly with the aforementioned slits in correspondence with the locking fork.

[0017] US-A1-2017 / 183911 discloses a portable drilling device equipped with a single clamping member, for blocking the movement of the drilling tools both in the longitudinal direction and also in rotation. This clamping member is of the forkshaped type, which requires the drilling tools to have respective seatings created laterally to allow the insertion of the fork. This leads to the same problem as the document discussed above.

[0018] There is therefore the need to perfect a horizontal drilling machine that can overcome at least one of the disadvantages of the state of the art.

[0019] To do this, it is necessary to solve the technical problem of optimizing the conditions for coupling and decoupling the rods to / from the head, substantially under all operating conditions.

[0020] One purpose of the present invention is to provide a horizontal drilling machine that guarantees a correct and effective coupling between each rod and the head, without requiring specific conditions of axial alignment of the rod, and without the risk of compromising the effectiveness and functionality of the threads thereof.

[0021] Another purpose of the present invention is to provide a horizontal drilling machine that guarantees an effective and specific unscrewing between the head and the rod, without interfering with the threaded couplings between the other rods, with low operating and maintenance costs and without requiring complex and detailed preventive operations of excavation and preparation of a dedicated installation area.

[0022] Another purpose of the present invention is to provide a horizontal drilling machine that reduces operator intervention to a minimum, allowing for a greater automation of the entire process.

[0023] A further purpose of the invention is to provide a horizontal drilling machine that is easier to construct and for which maintenance is simpler.

[0024] The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.SUMMARY OF THE INVENTION

[0025] The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

[0026] In accordance with the above purposes and to solve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a horizontal drilling machine according to the present invention comprises a support frame, for example a metal structural work suitable to be deliberately housed on the ground, or other support, to substantially define the direction, or the axis, along which the drilling is to be performed. It can be deduced that the support frame has a longitudinal development parallel to the axis along which the drilling is to be performed.

[0027] A drawing member or head is disposed sliding on the support frame, which is configured to be selectively moved along the drilling axis between one loading position and a drilling position. A plurality of drilling tools or rods are also part of the drilling machine according to the present invention, each of which is substantially formed by a central body, for example with an elongated tubular conformation, and is provided with a first, for example male, threaded end configured to cooperate, as will be disclosed, with the drawing member, and with a second, for example female, threaded end opposite and corresponding to the first threaded end.

[0028] This conformation of the drilling tools allows for a reciprocal axial screwing therebetween, forming a pack of tools with a desired length through which a drilling liquid is introduced under pressure.

[0029] In accordance with one aspect of the present invention, each of the drilling tools comprises at least one abutment block, advantageously two diametrically opposite, which extends radially from the central body in proximity to the first threaded end. More generally, each tool can have a plurality of abutment blocks, preferably distributed angularly.

[0030] Always according to the present invention, the drawing member comprises at least one at least partly rotating manipulation element provided with a centering seating. The latter is configured to axially house the central body of a corresponding drilling tool and is provided radially with at least one abutment tooth, which is configured to couple angularly to the abutment block.

[0031] Doing so means that the association between each tool and the drawing member occurs through the angular coupling of the abutment block to its corresponding abutment tooth. These, in fact, having an extension that is radial with respect to the central body and to the centering seating, respectively, cooperate kinematically with each other during the rotation of the manipulation element, defining a substantially bayonet type attachment and guaranteeing the association between the tool and the drawing member, without using the thread provided at the first end of the tool itself.

[0032] Therefore, the solution according to the present invention guarantees a correct and effective coupling between each tool and the drawing member, without requiring particular conditions of axial alignment of the tool, and without the risk of compromising the effectiveness and functionality of the latter's threads, since they are not affected in any way by the association operations.

[0033] The solution providing a substantially bayonet like association between the tool and the drawing member guarantees an effective and specific decoupling between the latter, without interfering with the threaded couplings between the other tools.

[0034] Therefore, any operator intervention is reduced to a minimum and a higher degree of automation of the entire process can be achieved.

[0035] With the solution according to the present invention it is possible to optimize the conditions of coupling and decoupling of the tools to / from the drawing member, substantially under all operating conditions.

[0036] According to some embodiments, the centering seating is located outside the manipulation element, preferably in correspondence with an external edge thereof. For example, it can be provided that the manipulation element has an internal cavity, into which the first threaded end of the drilling tools is insertable, and that the centering seating is located in correspondence with the inlet of the internal cavity. In this way, the centering seating can be cleaned and replaced very easily and quickly. This configuration is allowed, among other things, by the disposition of the support frame with a development parallel to the drilling axis, which allows for a travel of the manipulation element longer than that of the drilling tools.

[0037] In accordance with another aspect of the present invention, the support frame comprises a single clamping member, which is spaced apart from the loading position of the drawing member and is configured to cooperate selectively with the drilling tools and at least temporarily prevent both their axial movement and rotation.

[0038] In this way, the screwing and unscrewing of a new tool, with respect to the one cooperating with the single clamping member, occur directly through the rotation of the manipulation element, without the risk of any accidental decoupling between the tool and the drawing member, since the coupling between the two occurs substantially in a bayonet manner. Likewise, the single clamping member guarantees the hold of the threads of the external tools to the support frame.

[0039] With this solution according to the present invention management and maintenance costs are low, without requiring complex and detailed preventive operations of excavation and preparation of a dedicated installation area, since, by providing a single clamping member, even the sizes of the support frame can be optimized.

[0040] Preferentially, the single clamping member comprises a pair of jaws opposing each other with respect to the drilling axis, so as to grip the drilling tool from to reciprocally opposite sides. More preferentially, each jaw comprises at least one contact surface suitable to be pressed against the external surface of the drilling tool. Even more preferentially, each jaw comprises two contact surfaces. By providing two jaws equipped with contact surfaces, which are therefore configured to press on the drilling tool so as to lock its position, it is possible to act on each longitudinal point of the drilling tool without having to make the clamping member coincide with a specific longitudinal position, which allows to simplify the construction and operation of the machine according to the invention.

[0041] In accordance with another aspect of the present invention, the drawing member comprises a translating element, or slider, on which at least one kinematic member, for example a rack kinematic mechanism actuated by a hydraulic motor, is mounted, configured to actuate the movement of the drawing member with respect to the support frame along the drilling axis. Two or more substantially equivalent kinematic members can be provided for the benefit of a better management of the movement.

[0042] In accordance with another aspect of the present invention, the manipulation element is mounted axially mobile on the translating element and corresponding thrust springs are provided between the two, which exert an axial elastic action, specifically on the manipulation element. This action means that the manipulation element is constantly under tension, in order to exert a desired thrusting action on the tool, in particular during the steps of screwing to a tool in cooperation with the clamping member.

[0043] Doing so guarantees a correct screwing between the second threaded end of the tool managed by the drawing member and the first threaded end of the tool managed by the clamping member, safeguarding the mechanical integrity of the respective threads and guaranteeing a correct screwing between the two. Furthermore, the axial action of the spring guarantees a substantially automatic engagement of the tool in the drawing member, in particular with regard to the angular coupling between the abutment block and the corresponding abutment tooth.

[0044] In accordance with another aspect of the present invention, each of the drilling tools comprises a circular groove, which is made in proximity to the at least one abutment block, while the manipulation element comprises at least one locking lever configured to cooperate selectively with the circular groove in order to define a more solid axial retention of the tool, in particular situations in which it may prove useful. Preferably, the at least one locking lever is equipped with a hydraulic type actuation member.

[0045] In accordance with another aspect of the present invention, a lifting member is provided on the support frame, which is operatively associated with the single clamping member and is configured to selectively move the single clamping member between a position of cooperation with the drilling tools and a raised rest position, spaced apart from the drilling axis.

[0046] According to another aspect of the present invention, a horizontal drilling method is provided, comprising at least a first loading step in which a drawing member disposed sliding on a support frame is in one loading position and is progressively loaded with a plurality of drilling tools, each having at least one central body provided with a first threaded end configured at least to cooperate with the drawing member and with a second threaded end opposite the first threaded end, and a second drilling step in which the drawing member is moved into a drilling position along a drilling axis. In the first loading step each of the drilling tools is housed axially in the central body in a centering seating created in a manipulation element of the drawing member and with at least one abutment block, extending radially from the central body and disposed in proximity to the first threaded end, in a condition angularly coupled to an abutment tooth provided radially in the centering seating.

[0047] Preferentially, the method is carried out using the machine described above.DESCRIPTION OF THE DRAWINGS

[0048] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of an embodiment, given as a non-restrictive example with reference to the attached drawings wherein: fig. 1 is a three-dimensional view of a horizontal drilling machine according to the present invention; fig. 2a is a three-dimensional view of a drilling tool according to the present invention, in a first embodiment; fig. 2b is a three-dimensional view of a drilling tool according to the present invention, in a second embodiment; fig. 3 is a three-dimensional view of an extract of the horizontal drilling machine of fig. 1; fig. 4 is an opposite three-dimensional view of a detail of fig. 3; fig. 4a is a schematic front view of fig. 4; fig. 5 is a plan view of a detail of the horizontal drilling machine of fig. 1; and fig. 6 is a section along the line VI-VI of fig. 5.

[0049] We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example thereof, since the scope of protection is defined by the claims.

[0050] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION

[0051] With reference to the attached drawings, a machine 10 according to the present invention is a horizontal drilling machine for the horizontal drilling of terrains and, more generally, of mineral strata, in order to install new pipelines without having to carry out open-pit excavations.

[0052] The machine 10 according to the present invention substantially comprises a support frame 11 on which a drawing member, or more simply head 12, is disposed sliding, configured to be selectively moved along a drilling axis X between a loading position (shown in fig. 1) and a drilling position.

[0053] The machine 10 according to the present invention also comprises a plurality of drilling tools, or more simply rods 13, whose characteristics and functionalities will be explained in detail below. The rods 13 have a longitudinal axis L (figs. 2a and 2b).

[0054] The support frame 11 has a substantially box-like shape, elongated in the direction of the drilling axis X, and comprises a bottom wall 14 from which two lateral walls 15 extend upward to define a longitudinal compartment 16 in which the head 12 is specifically disposed sliding.

[0055] With particular reference to figs. 5 and 6, but not only, the head 12 comprises a translating element, or more simply slider 17, on which a manipulation element, or more simply manipulator 18, is mounted axially mobile.

[0056] In the example embodiment (figs. 3, 5 and 6), a pair of thrust springs 40 is provided, disposed elastically between the slider 17 and the manipulator 18, so as to elastically keep the manipulator 18 in an advanced position with respect to the slider 17. In this way, a possible axial thrust on the manipulator 18, in the opposite direction to the elastic action of the thrust springs 40, determines a damped axial movement of the manipulator 18 with respect to the slider 17, maintaining a contrasting axial tension on the manipulator 18 itself.

[0057] Each thrust spring 40 can be preloaded at will by means of corresponding preloading ring nuts 41, so as to deliberately adjust the contrasting axial tension on the manipulator 18 (figs. 3, 5 and 6).

[0058] The slider 17 comprises a plurality of wheels 19, or other known rolling elements such as sliders, bearings or suchlike, disposed in cooperation with the lateral walls 15 and the bottom wall 14 of the support frame 11 so as to guide and make uniform the selective sliding of the head 12 between the loading position and the drilling position.

[0059] Two kinematic members, or simply kinematics 20, are mounted on the slider 17, which actuate the movement of the head 12 with respect to the support frame 11 along the drilling axis X.

[0060] In the embodiment shown here, each kinematics is embodied with a rack gear system powered by a corresponding hydraulic motor. It is not excluded, however, that the kinematics 20 can be realized in any known forms different from the rack system, for example by means of catenaries, linear actuators, levers, friction systems or others.

[0061] The manipulator 18 comprises a rotating body 21, hollow axially with respect to the drilling axis X and provided at the head with a locking ring nut 22 (figs. 3 and 6). The rotating body 21 therefore has an internal cavity 21A coaxial with respect to the drilling axis X.

[0062] The rotating body 21 is selectively activatable in rotation both clockwise and counterclockwise by means of a hydraulic motor 23. A specific mechanical solution with chain transmission between the hydraulic motor 23 and the rotating body 21 is shown here (fig. 6); however, it is not excluded that this transmission can be made axially direct, or by means of belts, as well as in any other known way, in order to guarantee a desired rotation of the rotating body 21 with respect to the drilling axis X.

[0063] The locking ring nut 22, hereafter also rod drawer 22, comprises a centering seating 24 made coaxial to the drilling axis X and having a diameter coordinated, as we shall see, with the rod 13. As can be seen from figs. 3, 4 and 6, the locking ring nut 22, and therefore the centering seating 24, is located outside the rotating body 21, in particular immediately outside the internal cavity 21A, that is, in correspondence with its inlet aperture. Two abutment teeth 25 (figs. 4 and 4a) are also made on the centering seating 24, which extend radially toward the inside of the centering seating 24, defining corresponding stop walls 26.

[0064] A respective retaining plate 25A extends from each of the abutment teeth 25, positioned in correspondence with the face of the locking ring nut 22 in which the rods 13 are inserted (figs. 4a and 6). The retaining plates 25A have a thickness such that a rod can be inserted into the centering seating 24 without interfering with its elements that allow it to be locked, and thus allowing the rotation of the rod 13 around the drilling axis X, as will be better explained below. For this purpose, the plates 25A are preferably positioned symmetrically to each other with respect to the central axis of the locking ring nut 22, and define an inlet aperture 25B between them configured to allow the passage of the rod 13 with a certain insertion orientation, but to block its passage with other orientations, in particular with an orientation perpendicular to the predetermined inlet orientation.

[0065] In addition to the structure described above, the drawer 22 is configured so as to also have a friction coupling to the rods 13. To achieve this friction, the shape of the inside of the rod drawer 22 is adapted to the corresponding portions of the rods 13, for example by acting on the construction parameters such as dimensional, geometric, heat treatment and roughness tolerances. In this case, the friction guarantees the axial retention of the rods 13 after decoupling from the rod that remains constrained to the clamp. The fact that there is no mechanical retention allows the operator to easily remove the rod without carrying out any operation or command whatsoever.

[0066] In the event that this "retention" fails for various extraordinary reasons (wear of the components, excessive dirt or the presence of debris, displacement of the machine with respect to the initial position, etc.), the manipulator 18 also comprises two locking levers 27, mounted pivoting and opposing each other, with respect to the drilling axis X and in external cooperation with the locking ring nut 22. The locking levers 27 are configured to be selectively rotated by an actuator 28, so as to define a simultaneous and opposing movement in the direction of the drilling axis X.

[0067] The machine 10 according to the present invention also comprises a single clamping member, or more simply clamp 29, provided at a front end of the support frame 11, in a position spaced apart from the loading position of the head 12 (fig. 1).

[0068] The clamp 29 substantially comprises two jaws 30 opposing with respect to the drilling axis X and moved, each by a corresponding actuator 31, for example of the hydraulic type, so that they can be selectively moved contrasting each other toward the drilling axis X, so as to radially tighten the rods 13, at least temporarily preventing both the axial movement and also the rotation thereof (fig. 3).

[0069] The jaws 30 are configured to exert a pressure on the external surface of the rod 13, in particular each one on two distinct zones, angularly offset around the longitudinal axis L of the rod 13. In the example shown, each jaw 30 contains two contact surfaces 30A suitable to be pressed against the external surface of the rod 13, in particular of its central body 32. Each contact surface 30A is substantially tangent to the external surface of the rod 13. These contact surfaces 30A can be provided on respective sliding blocks removably mounted in the jaws 30. The contact surfaces 30A can be knurled, to improve the grip on the rod 13, and thus more effectively lock its rotation around the drilling axis X.

[0070] Furthermore, the clamp 29 is pivotally mounted on one of the lateral walls 15 of the support frame 11, and is operationally associated with a lifting member 31A, such as for example an actuator hinged to the support frame 11 or suchlike. In this way, the clamp 29 can be selectively moved between a position of cooperation with the drilling tools (as shown in fig. 1) and a raised rest position, angled with respect to the position of cooperation and spaced apart from the drilling axis X. This second raised position is particularly advantageous in the tool change operating steps, for example to arrange on the drilling axis X tools for widening or finishing the pilot hole made with the rods 13.

[0071] Each rod 13 is substantially defined by a central body 32 with a substantially tubular shape correlated to the centering seating 24 (figs. 2a and 2b), a first end 33 with male thread and a second end 34 with female thread, opposite and coordinated with the first end 33. As per fig. 3, the rods 13 are reciprocally coupleable by screwing the first and second ends 33 and 34 together, so as to define an axial rod 13 string of a desired length.

[0072] We must clarify that the central body 32 of the rods 13 is configured to withstand the considerable stresses that it is subject to by the combined actions of rotation, thrust and bending, like the rods of the state of the art.

[0073] Furthermore, each rod 13 comprises a pair of abutment blocks 35, in this specific case made diametrically opposite each other and extending radially from the central body 32, in proximity to the first end 33.

[0074] Each abutment block 35 laterally defines two stop surfaces 36 suitable to angularly couple to the corresponding stop walls 26 defined by the abutment teeth 25. In fact, in a condition wherein the rod 13 and the head 12 are coupled to each other, the central body 32 is inserted axially in the centering seating 24 and, following a rotation, the abutment blocks 35 couple angularly to the abutment teeth 25, defining the contact between the stop surfaces 36 and the stop walls 26 (figs. 4 and 4a). In the example shown, the two stop surfaces 36 are parallel or substantially parallel to each other. In particular, the two stop surfaces 36 can also be parallel to a plane containing the longitudinal axis L of the rod 13.

[0075] As stated above, the thickness of the retaining plates 25A is such that the abutment blocks 35 can be housed in the centering seating 24 without interfering therewith, so that when the rod 13 is rotated around the drilling axis X, from the orientation of insertion (shown in fig. 4a) to a locking position, the abutment blocks 35 can be locked between the bottom of the centering seating 24 and the retaining plates 25A. For this purpose, the abutment blocks 35 advantageously comprise a transverse abutment surface 35A suitable to abut against the retaining plates 25A. The transverse abutment surface 35A is advantageously flat, more advantageously also perpendicular or substantially perpendicular to the longitudinal axis L of the rod 13.

[0076] In the embodiment shown in fig. 2a, a circumferential seating 37 is created in proximity to the abutment blocks 35, on the opposite side to the first end 33, configured to selectively cooperate with the locking levers 27 so that the latter cooperate physically with the circumferential seating 37, in order to prevent the axial movement of the rod 13 both in one direction and in the other with respect to the drilling axis X.

[0077] In the embodiment shown in fig. 2b, the rod 13 is without the circumferential groove 37, without thereby departing from the inventive idea defined by the present invention.

[0078] The reciprocal conformation of the abutment teeth 25 and the abutment blocks 35 causes the rotation of the rotating body 21 around the drilling axis X to be transmitted directly to the rod 13, without in any way engaging the female thread of the first end 33.

[0079] In particular, since the abutment teeth 25 are each equipped with a right angle end, each of them has two stop walls 26, perpendicular to each other, both configured to abut against a respective stop surface 36 of the abutment blocks 35 (fig. 4a). In this way, the direct transmission of the rotation of the rotating body 21 to the rod 13 occurs in both directions of rotation.

[0080] Once these operations, which can be defined as a first step of loading the rod 13 into the head 12, have been completed, the head 12 is made to advance until the second end 34 contacts the first end 33 of a rod 13 already positioned engaged in the clamp 29.

[0081] At this point, by making the head 12 advance, the manipulator 18 is stopped by the contact between the rods 13 and slides axially with respect to the advancing slider 17. Progressively, the thrust springs 40 actuate the contrasting axial tension on the manipulator 18, until the rod string is formed.

[0082] Rotating the rotating body 21, and therefore the rod 13 coupled to the head 12, causes the second end 34 to screw relative to the first end 33 of the rod 13 onto the clamp 29.

[0083] The axial tension determined by the spring 40 is progressively transmitted onto the rod 13 of the head 12, so as to optimize the screwing action, safeguarding the threads.

[0084] Once complete screwing is achieved, the clamp 29 is released and the head 13 is moved forward until the drilling position is reached. At the operator's command, and without manually intervening on the machine 10, the clamp 29 is reactivated, the rotating body 21 rotates by a few degrees in the opposite direction to angularly release the abutment teeth 25 from the abutment blocks 35, and the retraction of the slider 17 is commanded, with a consequent extension of the springs 40 and repositioning of the head 12 in the initial loading position, leaving the rod 13 screwed onto the previous one.

[0085] Conversely, for the operations of extraction and reciprocal release of the rods 13, the head 12 is brought into the drilling position and constrained to the last rod 13 by means of an angular coupling between the abutment blocks 35 and the abutment teeth 25. In this operating condition, the retaining plates 25A lock the rod 13, through the abutment blocks 35, so that the rod 13 can be extracted by being pulled. The head is brought into the initial loading position. In this step, the head 12 and the corresponding drawer 22 may not immediately find the phase between the blocks 35 of the rods and the corresponding passage gap of the drawer. The springs will now begin to compress, allowing the head to continue to advance and rotate until alignment is found and the rod is free to enter the drawer.

[0086] After the newly coupled rod is extracted, the clamp 29 is activated to keep the rod still inside the drilling duct (the one that will be extracted in the next cycle) locked, and the rotating body 21 is activated in rotation to unscrew the two rods 13 from each other. Advantageously, this operation is performed with the head 12 in a position such that the progressive unscrewing of the rods 13 results in the corresponding loading of the thrust springs 40, again to preserve the integrity of the threads and guarantee a long life of the rods 13.

[0087] During the unscrewing of the rods 13, or in the event of jamming or problems of a different nature (for example excessive dirt, use of worn rods, lack of lubrication of the thread or suchlike), the locking levers 27 are brought into cooperation with the circumferential seating 37 of the rod 13 engaged, so as to lock it.

[0088] It is clear that modifications and / or additions of parts may be made to the machine 10, to the rods 13 and to the method as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims.

[0089] It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of horizontal drilling machine, drilling tool and corresponding drilling method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

[0090] In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

1. Horizontal drilling machine (10) comprising a support frame (11) on which a drawing member (12) is disposed sliding configured to be selectively moved along a drilling axis (X) between one loading position and a drilling position, and a plurality of drilling tools (13) each having at least one central body (32) provided with a first threaded end (33) configured at least to cooperate with said drawing member (12) and with an opposite second threaded end (34), characterized in that each of said drilling tools (13) comprises at least one abutment block (35) extending radially from said central body (32) in proximity to said first threaded end (33) and in that said drawing member (12) comprises at least one at least partly rotating manipulation element (18) provided with a centering seating (24) configured to axially house said central body (32) and provided radially with at least one abutment tooth (25) suitable to couple angularly to said abutment block (35).

2. Machine (10) as in claim 1, characterized in that said support frame (11) has a longitudinal development parallel to said drilling axis (X).

3. Machine (10) as in claim 1 or 2, characterized in that said support frame (11) comprises a single clamping member (29) spaced apart from said loading position of said drawing member (12) and configured to cooperate selectively with said drilling tools (13) and at least temporarily prevent both their axial movement and rotation.

4. Machine (10) as in claim 3, characterized in that said single clamping member (29) comprises two jaws (30) opposing each other with respect to said drilling axis (X).

5. Machine (10) as in claim 4, characterized in that each jaw (30) comprises at least one contact surface (30A) suitable to be pressed against the external surface of one said drilling tool (13).

6. Machine (10) as in one or other of the previous claims, characterized in that each of said drilling tools (13) comprises two or more abutment blocks (35) angularly offset from each other, and in that said centering seating (24) comprises two or more corresponding abutment teeth (25).

7. Machine (10) as in one or other of the previous claims, characterized in that said centering seating (24) is disposed outside said manipulation element (18).

8. Machine (10) as in one or other of the previous claims, characterized in that said drawing member (12) comprises a translating element (17) on which at least one kinematic member (20) is mounted configured to actuate the selective movement of said drawing member (12) with respect to said support frame (11) along said drilling axis (X).

9. Machine (10) as in claim 8, characterized in that said manipulation element (18) is mounted axially mobile on said translating element (17).

10. Machine (10) as in claim 9, characterized in that said drawing member (12) comprises at least one thrust spring (40) disposed in elastic cooperation between said translating element (17) and said manipulation element (18).

11. Machine (10) as in one or other of the previous claims, characterized in that each of said drilling tools (13) comprises a circular groove (37) created in proximity to said at least one abutment block (35) and in that said manipulation element (18) comprises at least one locking lever (27) configured to cooperate selectively with said circular groove (37).

12. Machine (10) as in claim 3, characterized in that it comprises a lifting member (31A) operatively associated with, and configured to selectively move, said single clamping member (29) between a position of cooperation with said drilling tools (13) and a raised rest position, spaced apart from said drilling axis (X).

13. Drilling tool (13) for a horizontal drilling machine (10) provided with a support frame (11) on which a drawing member (12) is disposed sliding configured to be selectively moved along a drilling axis (X) between one loading position and a drilling position, comprising at least one central body (32) provided with a first threaded end (33) configured at least to cooperate with said drawing member (12) and with an opposite second threaded end (34), characterized in that it comprises at least one abutment block (35) extending radially from said central body (32) in proximity to said first threaded end (33) and configured to be angularly coupled to an abutment tooth (25) provided in a centering seating (24) for the axial housing of said central body (32) and created in a manipulation element (18) of said drawing member (12).

14. Drilling tool (13) as in claim 13, characterized in that said abutment block (35) laterally comprises two stop surfaces (36), preferably parallel to each other.

15. Horizontal drilling method comprising at least a first loading step in which a drawing member (12) disposed sliding on a support frame (11) is in one loading position and is progressively loaded with a plurality of drilling tools (13), each having at least one central body (32) provided with a first threaded end (33) configured at least to cooperate with said drawing member (12) and with a second threaded end (34) opposite said first threaded end (33), and a second drilling step in which the drawing member (12) is moved into a drilling position along a drilling axis (X), characterized in that in said first loading step each of said drilling tools (13) is housed axially in said central body (32) in a centering seating (24) created in a manipulation element (18) of said drawing member (12) and with at least one abutment block (35), extending radially from said central body (32) and disposed in proximity to said first threaded end (33), in a condition angularly coupled to an abutment tooth (25) provided radially in said centering seating (24).

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