DESCRIPTION

The present patent concerns drilling heads, and more specifically it concerns a new piece of equipment for drilling with an improved advance system.

Techniques and systems for laying cables and plastic or metallic pipes are known which require the excavation of trenches or mini trenches. These techniques always require the execution of excavations, for which purpose it is necessary to break the road surface, interrupt railways or roads etc. Furthermore, these systems cannot be applied or are difficult to apply in specific conditions, for example in the presence of water courses, buildings etc. Pipe laying systems are also known which are called H D D (Horizontal Directional Drilling) systems and consist in the drilling of underground holes intended to become the seats where cables or plastic or metallic pipes can be laid with no need to make open excavations.

This technology belongs to the technologies known as "no dig" and eliminate important impacts both on the environment and on the existing structures and infrastructures.

The H.D.D. technology stands out from the other "no dig" technologies owing to the fact that it allows the active control of the drilling trajectory.

Other "no dig" technologies, for example the“drill pipe” technology, are also known, which are quite different from the H.D.D. technology and substantially consist in guided drilling with a cutting head, with no motor on board, with an external thrusting unit and gradual introduction of the pipes as the drilling operation continues.

In H.D.D., the underground hole is made by means of a drilling head which is guided and connected to a cable or duct or set of rods.

Dry drilling heads are known, as well as drilling heads working with the aid of a drilling fluid, with which the excess soil flows away through said drilling rods.

The drilling head is guided along trajectories which are defined in advance between pre- established starting and arrival points, in order to make the pilot hole. The drilling head is generally guided remotely, normally through a wired connection. Once the end of the excavation has been reached, the drilling head is disconnected and replaced with a boring device which during the boring step is pulled backwards, covering the trajectory in the opposite direction, in order to increase the diameter of the pilot hole until obtaining the desired size. This process can be repeated several times until obtaining the required diameter.

During this step it is also possible to stabilize the walls of the hole, for example by means of mud jets.

Once the boring step has been completed, the head of the pipe to be laid is coupled with the boring device and pulled inside the hole until reaching the starting point, thus completing the laying operation.

This technique largely solves the problem of the installation of underground mains and networks, since it is not necessary to carry out excavations and to break the road surface. With this system, in fact, it is possible to install ducts under roads, water courses, sea channels, communication routes such as highways and railways, both longitudinally and crosswise, or under buildings, natural parks etc.

This technology can also be usefully applied in the field of hydrogeological and geo- environmental recovery projects and in the decontamination of polluted areas.

The drilling members used at present in the equipment for horizontal directional drilling usually exert a hammering action or a rotary action, and pose some drawbacks, first of all the fact that they are noisy during drilling.

Furthermore, the movement of the drilling members during the drilling operation generates vibrations that in certain geological and environmental conditions should be reduced or even avoided.

Another drawback posed by horizontal directional drilling as described above lies in that before making the pilot hole it is necessary to carry out an accurate survey of the underground area, in order to precisely identify the characteristics of the soil to be excavated but also in order to locate any pre-existing structures or obstacles of another type, for example explosive devices.

For the planimetric and altimetric survey of the underground mains and networks, georadars are presently used, which however cannot be effectively employed in certain environmental situations, for example in the presence of water courses, railways etc. Furthermore, georadars do not provide any information regarding the nature of the detected obstacle, except for some cases, and the expertise of the user is of fundamental importance for the purpose of determining the type of obstacle met.

The subject of the present invention is a new type of drilling equipment with an improved advance system.

It is one object of the present invention to provide a piece of drilling equipment in which the weight of the drilling head is reduced to a minimum, wherein the drilling head has no rotary drilling members, and which furthermore for its operation needs only an electric wire and/or a possible duct for a pressurized fluid or gas to be used for moving the moving members.

A possible advantage of the present invention lies in that it minimizes the vibrations generated during the drilling operation, according to the conditions of the ground.

It is another object of the present invention to provide a piece of drilling equipment which for the drilling operation uses a head or drill that is operated by means of fluid dynamic or gas systems, thus reducing noise to a minimum, at least when the drilling head advances through a thrusting action and not through a hammering action.

It is another object of the present invention to provide a piece of drilling equipment which can also enlarge the hole and compact the hole walls during the drilling operation, thanks to the action exerted by radially expandable portions on the walls of the hole itself.

It is another important object of the present invention to provide a piece of drilling equipment which during the drilling operation is able to detect the presence of obstacles within a predetermined distance from the drilling head.

More specifically, for the purpose of limiting any risk of damage to existing underground mains or networks while at the same time guaranteeing safe operating conditions, the new equipment makes it possible to detect objects or obstacles in general containing ferromagnetic material.

In this way, it is possible to detect the presence of existing underground mains or networks, ducts, pipes, cables or, more specifically, explosive devices.

The detecting operation described above is made possible by the use of sensors installed on the machine, such as ferromagnetic sensors or even georadars, in the case where further examination and analysis should be needed.

According to the invention, the new equipment can also be used to understand what type of objects are present in the drilling seat, also in order to be able to carry out further clearing operations, if required.

The installation of position sensors, such as a servo inclinometer or similar devices, makes it also possible to control the advance and the path of the drill.

The new piece of equipment can thus be effectively used to carry out drilling operations also under roads, railways, water courses etc., as it makes it possible to verify that there are no obstacles of any type in real time during the drilling operation

As a consequence of the above, an advantage of the present invention lies in that it accelerates the drilling process.

Another advantage of the present invention lies in that it can be safely used also in situations in which there is the risk of finding inflammable or explosive gas, as the advance movement of the drill, which does not include rotations or high-speed alternate motion as in the conventional drills currently known, minimizes the risk of generating sparks.

These and other direct and complementary objects are achieved by the new drilling equipment with improved advance system.

The new drilling equipment comprises, among its main parts, an elongated drill or head, in turn comprising:

a first portion that can be expanded in the radial direction;

a second portion that can be expanded in the radial direction and is positioned before said first expandable portion, towards the front part of the drill;

an extendable joint mounted between said first portion and said second portion, configured to selectively assume a first contracted configuration, in which there is a minimum distance between said first portion and said second portion, and a second extended configuration, in which there is a maximum distance between said first portion and said second portion;

means and connections for the selective expansion of said first and said second portion;

means for the selective extension/contraction of said extendable joint;

a tip or nose forming the front end of said head or drill and suited to drill into the ground.

Each of said expandable portions can in turn comprise one or more expandable elements operating in a coordinated manner in order to improve the anchorage, stabilization and directionality of the drill, according to the type of soil.

The sequence of advance of the drill into the ground, once it has been correctly positioned on a positioning carriage or in a seat or a hole provided in the ground, includes the following steps:

a. radial expansion of said first portion, which adheres to the walls of the hole or seat, thus stabilizing the head;

b. extension of said joint, in such a way that the front part of the head advances and the tips penetrates the ground, thus drilling into it;

c. radial expansion of said second portion, which adheres to the walls of the hole;

d. radial size reduction of said first portion;

e. contraction of said joint, in such a way as to move forward the rear part of the head, which is pulled forward;

f. radial expansion of said first portion, which adheres to the walls of the hole;

g. radial size reduction of said second portion;

h. repetition of steps from b to g.

The succession of radial expansions and reductions of said first portion and said second portion causes the head to advance with no need to use rotary drilling members.

Said extendable joint is preferably a mechanical joint, made up of two bodies which slide with respect to each other, and wherein the relative movement between said bodies is obtained through fluid dynamic means or a gas or electromechanical means in general.

According to the invention, in the presence of hindrances and obstacles in the ground, for example small rocks, said selective extension/contraction means are operated repeatedly, so that the tip, which will conveniently be of the "beak" or "chisel" type, beats the obstacle and breaks it.

In a preferred embodiment, each of said radially expandable portions comprises one or more inflatable elements or hoses, wherein said hoses are selectively inflated by means of a system injecting/drawing a gas or a fluid into/from said hoses themselves.

In this case, the means and connections for the selective expansion of said first and said second portion comprise means and connections for the selective inflation of the hoses.

All or part of said means and connections for the selective inflation of said hoses can, for example, be obtained directly within the thickness of the mechanical parts connecting the portions and the extendable joints, for example by making grooves.

In this way, the drill will feature no external connections or pipes, which increase the overall dimensions of the drill and furthermore can also be broken or damaged or be of hindrance during the advance of the drill.

According to the invention, however, said radially expandable portions can be of another type, for example they can be made with one or more expandable elements using mechanical or electromechanical or pneumatic components projecting in the radial direction in various manners, or using deformable components, wherein an axial compression/dilation results in a corresponding radial expansion/reduction etc.

The function of each one of said radially expandable portions is to maintain a narrowed configuration when the portion needs to advance and a radially expanded configuration when the portion needs to be anchored to the walls of the hole, in order to stabilize the corresponding portion of the drill.

According to the invention, furthermore, said equipment comprises also a ferromagnetic sensor or another sensor suited to locate any obstacles which may be present in proximity to the drilling area, more specifically obstacles made of a metallic material, such as explosive devices, ducts, pipes or other types of obstacles. Said sensor is, for example, of the type described in document WO2018078575 filed by the same applicant, which is mentioned herein by way of reference.

According to the invention, furthermore, said head or drill is configured in such a way that it can be oriented and follow a predefined route. In this case, the new drilling equipment should conveniently comprise also one or more sensors suited to allow the position of said head to be detected during the drilling operation, such as, for example, a servo inclinometer installed on the head itself.

According to the invention, for example, said head may be articulated, meaning that it may comprise one or more orientable joints, wherein the orientation of the joints is predetermined and stable or adjustable and variable according to the needs.

Thus, the articulated head can be, for example, of the type described in the already mentioned document WO2018078575 filed by the same applicant, which is mentioned herein by way of reference.

In a possible solution, the front part of said drill, comprising at least said tip and possibly even said second portion, can rotate axially with respect to the remaining portion of the drill, wherein said tip is more specifically in the shape of a "beak" or a "chisel", in such a way that its position determines the inclination of the trajectory of advance in the ground, according to a defined and known curvature.

Consequently, by rotating the tip axially it is possible to modify the advance trajectory of the drill.

In this case, the drill comprises also at least one rotary valve mounted, for example and preferably, at the rear end of the drill, wherein said valve is configured to allow the injection of the fluid or gas or air used to inflate the hoses in the different rotated positions of the front part of the drill.

According to the invention, the new drill may possibly comprise also devices suited to draw, for example through suction, small samples of the ground through which the drill advances, thus carrying out sampling operations for the successive analysis of the ground.

According to the invention, the new drill may possibly comprise even devices designed to inject resin coating substances in the hole or on the hole walls, which, for example, can be done during the return movement of the drill.

The characteristics of the new piece of equipment are explained in greater detail in the following description, with reference to the drawings which are attached hereto by way of non-limiting example. Figure 1 shows a sectional view of the drilling head (1) or drill of the new drilling equipment, in the solution in which the radially expandable portions are constituted by inflatable hoses.

Figure 2a shows in detail a sectional view of the rear end (11) of the head (1), while Figure 2b shows in detail a sectional view of the front end (12) of the head (1).

Figure 3a shows in detail a sectional view of an extendable joint (4) belonging to the head (1) of Figure 1 in its contracted configuration (A), while Figure 3b shows a sectional view of the joint (4) of Figure 3a in its extended configuration (B).

Figures from 4 to 13 show the sequence of advance of the drill or head (1) in the ground (T). Figure 14 shows the new drill (G) constructed according to an alternative solution.

Figure 15 shows a detail of the rear part (110) of the drill (G) of Figure 14, where it is possible to observe a rotary solenoid valve (111) and a double-acting cylinder with through rod (81).

The new drilling equipment comprises an elongated drill or drilling head (1), shown in cross section in Figure 1.

Said drill or head (1) comprises a centre tubular element (6) holed axially in order to allow the passage of an injection/suction line (34) for a gas or a fluid and of at least one power supply cable (71) used to power at least one sensor (7) installed in proximity to the drilling tip (5).

Said tubular element (6), in its turn, is preferably made up of two aligned coaxial segments (61, 62) joined to each other (610) by means of an extendable joint (4) described and claimed here below.

In the particular solution shown in the figures, said drill (1) comprises a first radially expandable portion constituted by an inflatable hose (2) arranged so that it is coaxial with said tubular element (6).

Said hose (2), for example, can be of the type normally used in "packers", thus comprising an inflatable tubular body (23), for example made of rubber, included between two end portions (21, 22) fitted on a tubular cover (26) in turn containing a first segment (61) of said centre tubular element (6) and sliding with respect to it. More specifically, a first end portion (21) of said first hose (2) slides on said tubular cover (26), while the second end portion (22) is fixed on said tubular cover (26).

Said drill or head (1) comprises also a second radially expandable portion which in this case is constituted, too, by an inflatable hose (3), in turn comprising an inflatable tubular body (33), for example made of rubber, included between two end portions (31, 32) fitted on a tubular cover (36) containing the second segment (62) of said tubular element (6).

Between said first hose (2) and said second hose (3) there is an extendable joint (4) configured to selectively assume a first contracted configuration (A) (Figure 3a), in which there is a minimum distance between said first hose (2) and said second hose (3), and a second extended configuration (B) (Figure 3b), in which there is a maximum distance between said first hose (2) and said second hose (3).

The head or drill (1) comprises also means and connections for selectively inflating said first hose (2) and said second hose (3).

According to the invention, for example, by means of a first connection element (25) made in a first end portion (21) of said first hose (2) it is possible to selectively inflate/deflate said first hose (2) itself, through a dedicated injection/suction line (24).

In the second end portion (32) of said second hose (3) there is a further connection element (35), wherein an inflation fluid or gas is injected/drawn through an injection/suction line (34) passing through said tubular element (6).

The inflation gas or fluid is selectively blown into said first hose (2) and into said second hose (3) through at least one selector mounted on a rear element (8) installed on the rear end (11) of the head (1).

According to the invention, said injection/suction lines and connections can be obtained by means of grooves made in the walls of said tubular covers (26, 36) and/or of said segments (61, 62) of said tubular element (6).

The front end (12) of said head or drill (1) is made up of a tip or nose (5) suited to drill into the ground.

Preferably, inside or at the back of said tip (5) there is said at least one sensor (7), for example a sensor suited to detect the presence of metallic material in proximity to said drilling tip (5).

In the solution illustrated in detail in Figures 3a and 3b, said extendable joint (4) comprises a first body (41) constrained to said first hose (2) and a second body (42) constrained to said second hose (3), said second body (42) being suited to be translated with respect to said first body (41) and constrained to said second segment (62) of said tubular element (6).

The translation of said tubular element (6) with respect to said first body (41) of the joint (4) causes the advance of the second body (42) of the joint and consequently the extension of the joint (4) itself, which causes the tip (5) to advance.

On said joint (4), and more specifically on the sliding surfaces between said first body (41) and said second body (42) of the joint (4), there are bearings, gaskets and any other element which may be required to guarantee the necessary resistance to friction and tightness.

The movement of said tubular element (6) is controlled by means of fluid dynamic or gas systems, for example a double-acting cylinder (81) installed in said rear element (8).

According to the invention, with reference to Figure 14, said tip (5) of the drill (l ¹ ) can be of the " chisel" or of the "beak" type, wherein the position of said tip (5) in the ground determines the inclination of the advance trajectory of the drill (1), and wherein the front part (111) of said drill (G) comprising at least said tip (5) can be rotated axially and selectively with respect to the rear part (110) of the drill (5), in order to vary the advance trajectory of the drill (G).

In this case, the drill (F) comprises also at least one rotary solenoid valve (112) mounted, for example and preferably, at the rear end of the drill (F), wherein said solenoid valve (112) is configured to allow the injection of the fluid or gas or air used to inflate the hoses in the different rotated positions of the front part (111) of the drill (F).

Figures from 4 to 13 show the sequence of advance in the ground (T).

Figure 4 shows the hole (F) made in the ground (T).

The drill or head (1) is inserted in said hole (F), with both said hoses (2, 3) deflated (Fig. 5) and with the joint (4) in its contracted configuration.

The sequence successively includes the inflation of said first hose (2), so that it adheres to the walls (FI) of the hole (F), stabilizing the head (1) (Figure 6). The joint (4) is extended in such a way that the front part of the head advances and the tip (5) penetrates the ground (T) and drills into it (Figure 7).

Then said second hose (3) is inflated and adheres to the walls (FI) of the hole (F) (Figure 8). Successively, said first hose (2) is deflated (Figure 9) and then said joint (4) is contracted, so as to make the rear part of the head advance, and the head is pulled forward (Figure 10).

Said first hose (2) is inflated again in order to make it adhere to the walls of the hole (F), in a more forward position with respect to the preceding inflation operation (Figure 11).

The second hose (3) (Figure 12) is then deflated.

At this point the sequence is restarted, with the extension of said joint (4) intended to make the tip (5) advance and penetrate the ground (T), and then with the successive steps (Figure 13).

The inflation of said first hose (3) has thus the function of stabilizing the drill or head (1) when the joint (4) is extended to make the front part, that is, the drilling tip (5), advance, while the inflation of said second hose (3) has the function of stabilizing the drill or head (1) when the joint (4) is contracted to make the rear part advance.

Furthermore, the expansion of said hoses (2, 3) enlarges the hole (F), compacting and stabilizing its walls (FI). The hole (F) stabilized in this way can be used for other purposes, for example it can be directly coated with resin with no need for further enlargement operations or for the insertion of other cores.

These are the schematic outlines which are sufficient for the expert in the art to carry out the invention, consequently in the construction stage variants can be developed which do not affect the substance of the innovative concept introduced herein.

Therefore, with reference to the above description and the attached drawings, the following claims are expressed.