The present invention concerns a safety system for drilling equipment particularly but not exclusively used in a drilling machine for controlling the dangerous area around the machine and for interrupting the dangerous manoeuvres of the machine itself.

The present invention also concerns a drilling machine comprising the aforementioned safety system. More specifically, the safety system according to the present invention is used for preventing an operator from coming into contact with rotating or moving components of the drilling machine which are directly involved in the drilling process.

The present invention is particularly suitable for being applied to drilling machines that, operating in several technological fields, can require the workers responsible for auxiliary services to carry out manual interventions in areas around the machine exposed to danger, in particular close to the guiding antenna or mast on which the rotating head or rotary slides and close to the drilling axis on which the shafts used for the excavation, mixing, jetting and driving-in processes are located. Drilling machines require interventions by workers that can generally be divided into three types: interventions of first mounting, maintenance interventions and interventions simultaneous to the work manoeuvres.

In the first two types of interventions, usually performed in the workshop, the experience of the skilled workers, the specificity of the problems and common practice make this step be considered not particularly dangerous. In the third type of intervention, in which manual interventions are required during the work steps, for example to add or remove the drilling shafts in the area close to the mast, there is a high exposure to risks since the operations are carried out on moving parts and are routinized and this physiologically causes a drop in attention by those repeatedly performing the same action; moreover, such interventions must be quick so as to reduce as much as possible the intervention time and increase productivity.

In the present description, dangerous area is meant to indicate the region of space around the guiding antenna where the rotating head slides and the region of space near the drilling area.

For these reasons, in order to allow the worker to gain access, during the normal operations of the machine, to the mobile parts of the machine itself that are directly involved in the drilling process, it can be thought of to install, around the dangerous area, protections such as fixed barriers or guards, mobile barriers or guards with interblock, sensitive protection devices or a combination thereof. Such protections must prevent access to the dangerous area during any dangerous movement.

In the case in which the mobile barriers are opened or when the sensitive protection devices are activated by the entry of an object into the dangerous area, the dangerous drilling manoeuvres must be blocked quickly and safely: standards require instantaneous blocking at least of the rotation of the shaft and alternatively simultaneous and instantaneous blocking both of the rotation and of the translation movements of the driving head.

As long as the mobile barriers remain open or while the sensitive devices remain activated, it is possible to reactivate the rotation of the shafts and the sliding of the rotating head only by selecting, through a suitable selector, a limited operating mode. In this limited operating mode all of the manoeuvres are suitably slowed down to values such as to eliminate the danger and allow inspection of the parts or manual interventions to be carried out.

In order to return to the normal functioning mode, i.e. the work mode, it is necessary that the interblocked mobile barriers are closed and reset or the sensitive protection devices are no longer active and have been reset, the normal functioning mode is selected through a suitable selector and the start command is triggered.

It is known in the field to use mobile guards with interblock made in the form of containment cages, arranged around the work components of the machine to isolate the dangerous area. Such containment cages generally consist of one or more load-bearing frames, made through tubular elements or shaped metal sheets forming its external shape, and metallic or plastic grids, meshes or other screens taking up the area enclosed by such a shape. Such load-bearing frames can for example be hinged at points integral with the mast so as to be able to open by rotating on a horizontal plane, when the mast is arranged vertically, and leave free access to the dangerous area.

These kinds of barriers or "guards" in closed position, i.e. in work condition, have substantial bulks that generally are greater in the horizontal direction than the shape of the rotary head or of the clamps in order to be able to receive the rotary itself inside the protected volume. Such bulks are linked to the need to delimit a sufficiently large hazardous area, i.e. to keep the operator sufficiently far away from the hazard represented by the rotating shafts.

Moreover, the possible presence has to be considered of mechanical loading-aid means, such as for example automated loading arms, the so-called rack or revolver loaders, or articulated cranes, which, in order to be able to operate correctly, should be contained inside the protected volume defined by the barriers.

The aforementioned substantial bulks, however, for various reasons constitute a severe limitation of the operating capabilities of the machine. In particular, such bulks do not allow drilling to be carried out close to walls or corners formed by two walls, since when the machine is brought close to the walls the barriers make contact with such walls, preventing the drilling shafts from getting closer further. In this way, it would be possible to carry out no "wall-flush" drillings which are typical of consolidation and restructuring works. In the same way, in order for it to be possible to open the barriers, it is necessary to have sufficient space around the mast to allow the rotation or translation movement without interferences occurring with obstacles during the trajectory of the movement.
The presence of the barriers, therefore, constitutes an obstacle to the manoeuvres and is limiting for the drillings that can be carried out.

The aforementioned limitations are not compatible with the confined spaces of building sites in which drilling machines generally work, in particular in an urban environment, in which the agility of the machine is essential. The bulk of the barriers, also in open condition, hinders the step of adding or removing shafts into/from the drilling string.
Moreover, the need to carry out continuous opening and closing of the barriers to load the shafts results in an increase in work time and requires complication of the hydraulic and electrical systems to manage the actuation of such barriers.

A further limitation of this solution is the increased weight of the drilling machine, with a consequent reduction of the stability due to the frontally overhanging positioning of such barriers.

The use in horizontal drillings (tie rods) with very low heights, less than 1.6 metres, would also necessitate barriers being arranged for the entire length of the mast, so as to always protect the operator whatever position he/she is in. In this case, however, these barriers would have points of contact and interference with the ground and would make the loading of the shafts awkward, since the mobile parts for access to the shafts are substantially heavy, given that the length of the shafts themselves can even reach ten metres.

An alternative known solution consists of using sensitive devices, such as electrosensitive, photosensitive, laser, optical, radar, ultrasound or thermal devices. Such devices are arranged for producing a monitoring area that in turn at least partially comprises the dangerous area and to detect the presence and/or the passage of a body through such an area.

In the case in which an object crosses such monitoring areas, such passage triggers the sensitive devices causing the functions of the machine to stop. This solution also has some drawbacks. Such drawbacks are manifest, in particular, during drilling carried out with the supply of air (in deep hole drilling with hammer, commonly known as DTH) or water (tricone drilling or with hammers at the head and rotopercussions) or cement (injection and jetting) or during the mechanical mixing of the soil. During drilling or mixing, indeed, a lot of debris is projected from the excavation upwards due to the injection pressure or the motion of the shafts. In the same way, sprays of water, mud or cement can be projected upwards.

Such debris or sprays during their motion can, therefore, cross the monitoring areas by the sensitive devices. Such crossing can take place both from the excavation axis towards the outside of the dangerous area but also from outside of such an area towards the inside due for example to the bouncing of the debris against the parts of the machine, for example against the mast.

The crossing of the debris or of the sprays of water, mud or cement causes an undesired triggering of the sensitive devices and consequently causes the machine to stop even though there is no actual condition of danger due to the passage of people. This can lead to continuous stopping of the machine, severely slowing down work, also considering the length and complexity of the operations imposed by the standards for reactivating normal functioning mode.

A purpose of the present invention is to make a safety system for a drilling machine that overcomes the aforementioned drawbacks of the prior art, preventing direct contact with the rotary parts, eliminating at source the risk deriving in the dangerous area during the work steps of the machine, without limiting operating capabilities and at the same time allowing safe and easy access to the area of the tools during the loading or maintenance steps of the tools themselves.

Such a purpose is achieved, in a first aspect of the present invention, with a safety system having the characteristics according to claim 1.

In a second aspect of the invention, such a purpose is achieved with a drilling machine having the characteristics according to claim 8.

In a third aspect of the invention, such a purpose is achieved with a process having the characteristics according to claim 14.

In a fourth aspect of the invention, such a purpose is achieved with a process having the characteristics according to claim 15.

Further characteristics of the device are the object of the dependent claims.

In a particular embodiment of the machine according to the invention, the longitudinal sliding of the distal end (9D, 90C) along the guiding antenna (3) is driven by means of a linear actuator (61) and flexible transmission means (62, 64) connected to the elements of the screen (9, 90).

In a particular embodiment of the machine according to the invention, the segment (9A-9D, 90A-90C) furthest from the rotary (5), called distal element (9D, 90C), is mounted on guides so as to be able to slide along the antenna (3).

In a particular embodiment of the machine according to the invention, the segments (9A-9D, 90A-90C) of the extensible screen (9, 90) have mechanical resting abutments for defining the position of the elements when they are completely extended and/or for gathering them in a contracted configuration.

In a particular embodiment, the machine according to the invention comprises a first slider unit (82) fixed in correspondence with or in the proximity of the proximal end (9A, 90A, 900A) of the screen (9, 90, 900), and a second slider unit (82A) fixed in correspondence with or in the proximity of the distal end (9D, 90C, 900B) of the extensible screen (9, 90, 900), and the first (82) and the second slider unit (82A) are arranged for driving the screen (9, 90, 900) causing it slide, extend and retract along the guiding antenna (3).

In a particular embodiment of the machine according to the invention, the first slider unit (82) is arranged for driving the proximal end (9A, 900A) of the screen (9, 900) making it slide according to a first direction (FT1) transversal with respect to the guiding antenna (3), and the second slider unit (82A) is arranged for driving the distal end (9D, 900B) of the screen (9) making it slide according to a second direction (FT2) parallel to the first direction (FT1).

In a particular embodiment of the machine according to the invention, the extensible screen comprises at least one segment provided with flexible or deformable walls capable of shortening and lengthening longitudinally to the axis of the segment itself and/or to the longitudinal axis of the drilling string.

In a particular embodiment of the machine according to the invention, the extensible screen comprises a single segment, and the extensible screen is arranged for shortening and lengthening longitudinally thanks to the deformations of the segment itself.

In a particular embodiment of the machine according to the invention, the at least one segment provided with flexible or deformable walls of the extensible screen comprises a tubular sleeve (900, 900^III, 900^IV).

In a particular embodiment of the machine according to the invention, such a tubular sleeve (900^IV) can be formed by a strip wound in a helix so as to form a plurality of coils, and so that the edges of two adjacent coils partially overlap one another.

In a particular embodiment of the machine according to the invention, the at least one segment provided with flexible or deformable walls of the extensible screen comprises at least one reinforcing ribbing or spiral (99) comprising a substantially rigid wire that winds in a helix.

In a particular embodiment of the machine according to the invention, the at least one segment provided with flexible or deformable walls of the extensible screen comprises at least one substantially annular reinforcing ribbing or hoop (100).

In a particular embodiment of the process according to claim 14, the operations F.3) and F.4) take place simultaneously.

In a particular embodiment of the process according to claim 15, during step F.8) the extensible screen (9) is moved integrally with the rotating head (5) in the aforementioned transversal direction with respect to the guiding antenna (3).

The document US3078933 discloses a drilling machine provided with a horizontal auger enclosed in a telescopic cage; such a cage is not able to translate perpendicular to the axis of the auger.

The advantages that can be obtained with the present invention will become clearer, to those skilled in the art, from the following detailed description of some particular non-limiting embodiments, illustrated with reference to the following schematic Figures.

• Figure 1 shows a side view of a drilling apparatus arranged with a safety system according to a first embodiment of the present invention, applied to a drilling machine, in extended configuration;
• Figure 2 shows a partial side section (fig. 2A) and a front view (fig. 2B) of a second embodiment of the safety system with a first variant of motorisation, in extended configuration.
• Figure 3 shows a partial side section (fig. 3A) and a front view (fig. 3B) of a third embodiment of the safety system, with a second variant of motorisation, in extended configuration.
• Figure 4 shows a front view of the previous embodiments in the loading step of a shaft (fig. 4A) and of an armature (fig. 4B), in which the system is collected in a high position of the mast and transversally displaced.
• Figure 5 shows a front view of the previous embodiments in which the system is collected in a low position of the mast and transversally displaced.
• Figure 6 shows a partial side section (fig. 6A) and a partial front section (fig. 6B) of a fourth embodiment of the safety system with a third variant of motorisation, in collected configuration.
• Figure 7 shows a side view of a fifth embodiment of the safety system with a second variant of motorisation, in extended configuration.
• Figure 8 shows a partial side section (fig. 8A) and a partial front section (fig. 8B) of a sixth embodiment of the safety system with a second variant of motorisation, in extended configuration.
• Figure 9 shows a front view of the safety system of Figures 8A, 8B in collected configuration at the bottom.
• Figure 10 shows a partial side section (fig. 10A) and a partial front section (fig. 10B) of the safety system represented in Figures 8A, 8B and 9, in collected configuration at the top.
• Figure 11 shows a partial front section of the embodiment of Figure 10A, 10B in collected configuration at the top, with the rotary laterally displaced with respect to the antenna.
• Figure 12 shows a side view of an eighth embodiment of the safety system with a first variant of motorisation, in extended configuration.
• Figure 13 shows a partial side section of a ninth embodiment of the safety system with a variant embodiment of the screen, shown in extended configuration (fig.13A) and in collected configuration (fig.13B) .
• Figure 14 shows a partial side section of a tenth embodiment of the safety system with a variant embodiment of the screen, shown in extended configuration (fig.14A) and in collected configuration (fig.14B) .
• Figure 15 shows a partial side section of an eleventh embodiment of the safety system with a variant embodiment of the screen, shown in extended configuration (fig.15A) and in collected configuration (fig.15B) .

As shown in Figure 1, the drilling machine, suitable for all excavation technologies by rotation, rotopercussion, vibration, driving-in and mixing and injection, suitable for being used for example to make piles, micro pile supports, tie rods or mechanical mixing and wholly indicated here with numeral 1, substantially comprises a base machine 2, for example mounted on tracks or wheels, which allow movement on the building site, a guiding antenna or mast 3, on which the drilling means slide, and a linkage 4 that allows the movement of the antenna with respect to the machine-base 2 to take it from an enclosed configuration, used for transportation, to a work configuration in which the mast 3 can be arranged vertically, inclined or horizontal. At least one rotating head 5, also called rotary, which applies the torque to the drilling string 6 and can slide along the antenna to cause the tool to move forwards or backwards in the excavation is mounted on the guiding antenna 3. Alternatively, an excavation system can be mounted that uses percussion and/or vibration in addition to rotation.

Conventionally, in the present description, by "upper end of the antenna 3" the end is meant which during use is furthest from the tip of the drilling string, and by "lower end of the antenna 3" the end is meant that during use is closest to the tip of the drilling string.

At the base of the guiding antenna 3 there can be clamps 7, in particular at least one pair, which allow the string already driven into the excavation to be held and the rotary to be disconnected or a shaft to be disconnected by unscrewing it from the string 6. The clamps 7 can, in an equivalent manner, comprise a clamp and an unscrewer. Figure 1 also shows a possible auxiliary winch used for moving the drilling accessories (like shafts 6A or armatures 23) to be fixed to the hook 22 or to suitable lifting accessories.

As shown in Figure 2, the rotary 5 can slide along the antenna 3 for example through the interposition of a slider unit 82 that can move longitudinally along the mast, for example guided on the suitable longitudinal guides 3A and moved by a suitable known pull-push system, for example of the type with chains with cylinder or a geared motor. Preferably the guides 3A integral with the mast 3 comprise elongated profiled elements in which it is possible to create a mechanical contrast on at least 3 sides. Advantageously, they are profiled with a closed, prismatic or "C-shaped" section.

The rotary can therefore carry out longitudinal strokes to the antenna 3 between an upper end close to the head and a lower end close to the clamps 7.

According to an aspect of the invention, the safety system comprises a side displacement system 8 fixed, or in any case arranged for being fixed, to the guiding antenna 3 so as to move the rotary 5 both longitudinally to the guiding antenna 3, and in a transversal direction, and preferably perpendicular, to the antenna 3. Preferably, the side displacement system 8, is arranged for moving the rotating head in a direction FT1 perpendicular not only to the antenna 3, but also to the ideal plane passing through the axes of the guiding antenna 3 and of the shafts of the drilling string 6, as indicated in Figure 2B.

The side displacement system 8 can comprise a first slider unit or carriage 82 mounted on the antenna so that it can slide along it, being guided longitudinally on the guides 3A. The first slider unit 82 in turn comprising:

• a first slider 81 mounted so as to be able to slide along the guiding antenna 3 for example along suitable sliding guides;
• a second slider 80, like for example a carriage or slide, mounted so as to be able to slide in a guided manner, on the first slider 81, for example along suitable guides 83 formed on the first slider 81.

The guides 83 extend transversally, and more preferably perpendicularly, to the guiding antenna 3 and can be formed for example as a mechanical contrast prismatic guide , or a groove or furthermore a tubular (circular or prismatic) profile with elongated shape (in the transversal direction of movement) on which the second slider 80 is coupled and mutually guided. The rotary 5 can be fixed to the second slider 80, or include, in an irremovable manner, the second slider 80 itself.

The side displacement system 8 also comprises an actuator that is used to drive the movement of the second slider 80. Said movement can for example be linear, like for example a hydraulic or pneumatic cylinder, or rotary - for example electric motor with screw and nut screw-type shaft - connected between the first slider 81 and the second slider 82, advantageously fixed to the first slider to facilitate the installation of the supply systems.

Preferably, the actuator 11 is a hydraulic cylinder arranged transversally, and more preferably perpendicularly, with respect to the axis of the antenna 3. Figure 2A refers to a start of processing condition of the drilling machine 1, with the rotary 5 lifted with respect to the lower end stop position and with a drilling string 6 connected to the rotary. The string 6, which can comprise a plurality of shafts 6A, receives the motion of rotation and of translation along the mast 3, from the rotary 5. In this start of drilling condition shown in Figures 2A and 2B it is necessary to protect and/or isolate the dangerous area surrounding the drilling string 6 for preventing worksite personnel fro getting close and coming into contact with the moving parts involved in the drilling process. In particular, it is necessary to eliminate the danger of a person being able to get caught in the rotating shafts and consequently being pulled.

In order to achieve such an objective, the safety system of the present invention comprises an extensible screen 9, reversibly extendable and retractable along the guiding antenna 3, thus of variable length, in particular proportional to the stroke of the rotary 5 and which is driven so as to pass from a contracted or collected configuration 9' to an extended configuration 9, said longitudinal movement taking place by guiding a part thereof at the mast 3, in particular said part being the end opposite the part fixed to the rotary 5.

Preferably, the screen 9 encloses and surrounds the drilling string 6 completely or at least for a fair extension thereof. The screen 9 can be coaxial to the drilling string or even eccentric with respect to the drilling axis defined by the axis of the drilling string 6, and be equipped with circular cross sections (or in any case profiled with closed sections) and preferably have a length proportional to the stroke of the rotary 5 along the antenna 3, so as to cover preferably almost entirely the string 6 for its extension in length.

The screen 9, in its lowest portion does not pass beyond the clamps 7 to contain its circumferential dimensions and reduce the bulks and therefore advantageously reaches a height near the clamps 7, preferably at a distance DAX not greater than 0-0.5 metres, and more preferably not greater than 0.2 metres from them (in particular from the one mounted at the top with respect to the other one(s)), and extends in a longitudinal direction preferably until it reaches close to the lower face of the body of the rotary 5, such as to completely or almost completely cover the longitudinal extension of the shafts 6 in front of the antenna 3.

The upper end 9A of the screen 9, also called "proximal end" in the present description because of the two ends of the screen 9 it is the one closest to the rotary 5, in order to move in a synchronised manner with the movement of the rotary 5 imparted by the side displacement system 8 in the longitudinal direction on the antenna 3, can be connected in a direct manner to the side displacement system 8, in particular to the slider 82 or more advantageously to the rotary 5 or to the slider 80.

The previous preferred values of the distance DAX substantially reduce the risks of workers suffering accidents by involuntarily touching the drilling string while it is rotating. Preferably, the proximal end 9A of the screen 9 is fixed integrally to the rotary 5 or to the slider 80 so as to follow, in a synchronised manner, at least the longitudinal sliding of the rotary along the guiding antenna 3.

With the direct connection the upper end of the extensible screen 9 can be bolted or welded to the slider 80 or even to the rotary 5, so as to be pulled longitudinally (and laterally as will be explained hereafter), by the motion of the slider 80. In the case of an indirect connection, the upper end 9A of the extensible screen 9 can be held by a cable or other flexible means driven by a winch or other rotary actuator (not shown) fixed to the antenna 3.

In this way, when the rotary 5 descends towards the base of the antenna, the actuator will unwind the cable that holds the upper end 9A of the screen 9 so that such an end descends in a synchronised manner to the stroke of the rotary 5, acting as a "hydraulic spring". The lower end 9D of the screen 9 (Figure 2A, Figure 2B), also called "distal end 9D" in the present description because it is located further away from the rotary 5 with respect to the proximal end 9A, can, on the other hand, slide in the longitudinal direction of the antenna independently from the motion of the rotary 5 and of the side sliding system 8.

Moreover, such a lower end can be kept at a predetermined axial height, and in particular at a minimum height above the clamps 7, independently from the motion and from the position of the rotary 5 and of the side sliding system 8.

In particular, said lower end 9D can be rested on a lower mechanical abutment or be directly rested on the clamps 7.

The attachment of the upper end 9A of the screen 9 to the rotating head 5 and/or to the slider 80 makes the safety system easier to install on different types of machines, in general simplifies the mechanical and circuit construction of the system and makes it easier to keep it permanently mounted on the drilling machine 1 during a large number of manoeuvres and operating situations.

In the embodiment shown in Figures 2A and 2B, the screen 9 comprises a plurality of segments, in particular:

• at least one upper segment 9A equipped with axial movement synchronised with the rotary 5 ;
  • a lower segment 9D positioned on the lower end during the operative drilling step; and possibly
  • one or more intermediate segments 9B, 9C so as to cover, when extended, the stroke of the rotary 5.

Again for the sake of simplicity of illustration, the antenna 3 is shown vertical but it should be understood that in the various operative conditions it can be inclined frontwards, backwards or sideways with respect to the base machine 2. The segments 9A, 9B, 9C, 9D of the screen 9 are shown sectioned in Figure 2A in order to allow the drilling string 6 that passes inside them using the suitable linkage 4 for positioning the antenna 3 to be seen. As shown in such a Figure, they can have closed cross sections so as to completely contain and surround the drilling string 6.

The segments 9A, 9B, 9C and 9D can be made with progressively increasing cross sections, so as to be able to be inserted inside one another in coaxial position and in a mutually sliding manner in the longitudinal direction forming a telescopic-type assembly.

Advantageously, at least the segment 9A closest to the rotating head 5 has an average or maximum diameter or more generally outer width, according to a direction parallel to the ideal plane passing through the axes of the guiding antenna 3 and of the shafts of the drilling string 6 (Figure 2B), not greater than the maximum diameter or outer width of the rotary 5, so as to reduce the overall bulk of the screen 9 and facilitate the manoeuvres of the machine 1 during drillings in restricted spaces, like for example in urban areas.

Each segment, as can be seen in Figure 2A, is preferably equipped with upper and lower edges or abutments that act as mechanical stops for the relative sliding of each segment with respect to the one immediately inside and with respect to the one immediately outside. In this way, the segments are prevented from slipping out and decoupling.

The edges or abutments can also be dismountable, for example bolted, in order to facilitate the insertion of a segment of screen inside the other and then remountable once insertion has been carried out. The segments 9A, 9B, 9C and 9D of the telescopic screen can be made of rigid material, preferably of the metallic, light or lightened type, of low thickness. Possibly, each segment 9A-9D can be made from perforated metal plates or from gratings with small-sized holes, preferably no larger than 20 mm to prevent the fingers of a worker from entering but at the same time allow the shafts to be visible from the outside when they are in rotation and to allow the possibility of material coming out from the inside (for example the drilling debris) or allow easy cleaning from the outside.

Alternatively, they can be made of plastic material in order to further reduce the weight and possibly be transparent to increase internal visibility. In a further alternative, there can also be a combination of the previous solutions described.

Preferably, the side displacement system 8 also comprises a second slider unit 82A mounted on the antenna so that it can slide along it. The second slider unit 82A preferably in turn comprises:

• a third slider 81A mounted so as to be able to slide along the guiding antenna 3 for example along suitable sliding guides;
• a fourth slider 80A, like for example a carriage or slide, mounted so as to be able to slide in a guided manner, i.e. along linear guides, on the third slider 81A, for example along suitable guides 83A formed on the third slider 81A and that can be similar to the guides 83 described earlier.

The lower or distal segment 9D is advantageously fixed to the fourth slider 80A or be an integral part thereof or further more contain the abutments for coupling with the guides 83A to carry out the side movements.

The slider 80A can be driven by an actuator 11A that can for example be linear, like for example a hydraulic or pneumatic cylinder, or rotary - for example electric motor with screw and nut screw-type shaft - mounted on the third slider 81A. Advantageously, the second slider unit 82A slides as a whole along the same guides 3A along which the first slider unit 82 slides, if necessary using guide means such as rollers or sliding blocks to avoid wear.

The function of the second slider unit 82A is to maintain the coaxiality of the lower section of the screen 9 with the upper rotary and therefore with the drilling string 6, avoiding translations or misalignments of the screen elements 9B, 9C and 9D on the plane perpendicular to the longitudinal axis of the antenna 3.

The function of the guide means of the second slider unit 82A is to prevent, when the antenna 3 is oriented with strong inclination with respect to the vertical, the extensible screen 9 from tending to belly, i.e. to be arranged in a deformed configuration according to a curved line. Indeed, in such a deformed configuration the segments of the screen 9 could come into contact with the string of rotary shafts 6 or they could tend to jam together preventing the telescopic movement.

Advantageously, the segments of the screen 9 in the abutment parts will also be partially guided with respect to one another so as to reduce the flexing due to its own weight. If this is not sufficient, many guides at the mast 3 can be inserted and connected to other segments of the screen 9.

The slider units 82, 82A belonging to the side displacement system 8 are preferably dismountable from the elements of the screen 9A, 9B, 9C or 9D, for example bolted, in order to facilitate the insertion of one screen segment inside the other and then remountable once insertion has been carried out. In any case, the distal screen 9D can quickly decouple from the antenna 3, dismounting one of the two attachment systems that make it integral either with the slider 80A or with the slider 81A.

In the embodiment shown in Figure 2A, the dimensions of the section of the most inner screen segment (9A in the case of Figure 2A) are such as to be able to house the shafts of the drilling string and the floating or system for damping and motion transmission to the shafts 6 from the rotary 5, in directions perpendicular to the antenna 3.

In the condition of Figure 2A,2B, with the screen 9 completely extended, the upper screen segment 9A is held in suspended position by the slider unit 82 or by the rotary 5 or by the second slider 80 to which it can be constrained (or by a flexible tensioning means in the case of indirect installation), whereas the intermediate segments 9B, 9C and 9D are preferably each hung at the previous segment through the abutment edges and tend to be arranged in a position completely extracted through the effect of its own weight, when the antenna 3 is arranged in substantially vertical configuration.

Such an effect of its own weight is effective only while the inclination of the antenna remains within a limited range with respect to the vertical, but many types of processing are limited to this type of configuration: for example water wells, geothermal wells, core boring, ....

When, on the other hand, the antenna is very inclined, or close to horizontal or even sub-horizontal the segments 9A-9D no longer tend to spontaneously extract and therefore it is preferable for the screen 9 to be driven or motorised to reach and maintain the extended or retracted configuration. For this reason, the lower screen segment 9D can be driven/motorised in a first variant of motorisation through a system with at least one motorised pinion 41 that engages on at least one rack 42 integral with the antenna 3 and parallel to the guides 3A.

Said motorised pinion is preferably mounted, or in any case constrained to the slider unit 82A that moves slidably guided along the antenna 3 and thus substantially parallel to the mounting direction of the rack 42. The rack 42 can be equivalently replaced for example by a roller chain. In the case in which for reasons of stability and symmetry it is necessary to mount two racks 42' and 42" (Figure 2B) they will preferably be mounted opposite with respect to the longitudinal middle plane of the antenna 3.

As shown in Figures 3A, 3B, a safety device according to a particular embodiment of the invention can have a second type of motorisation, made through a flexible means (cable or chain) in a closed loop (with two branches, an upper one for lifting and a lower one for lowering). The rotation actuator 43 can be a winch or a geared motor. In an advantageous solution, the actuator 43 is a winch with two cable branches, wherein the upper branch 44 for lifting and the lower branch 45 for lowering, wind/unwind in a synchronised manner on the same drum.

The upper cable branch 44 is relayed through an upper pulley 46 fixed to the antenna 3 or to the upper head and connects to the screen 9D, in particular in an upper area thereof or directly to the slider unit 82A. The lower cable branch 45 is relayed through at least one lower pulley 47 fixed to the antenna 3 and connects to the screen 9D and in particular to a lower area thereof or to the slider unit 82A. In this way, if the actuator 43 is not actuated, the slider unit 82A and therefore the lower screen 9D stay in a fixed position with respect to the antenna 3 and such a position is maintained independently from the motion of the rotary 5.

When the actuator 43 is activated to wind a certain amount of cable 44 on the drum, it will simultaneously unwind an equal amount of cable 45 obtaining a sliding of the lower screen 9D towards the upper end of the antenna 3. Similarly, by reversing the motion of the rotary actuator 43 there will be sliding of the lower screen 9D and of the slider unit 82A, towards the lower end of the antenna 3. Thanks to this actuation/motorisation system of the screen 9, it is possible to always drive a sliding of the screen 9D upwards or downwards along the antenna 3 in all possible operative configurations (i.e. inclinations) that can be taken up by the antenna.

The safety system also comprises a sensor that detects the position of the distal end 9D of the screen 9; more specifically, such a sensor can detect the completely extended configuration of the screen 9, when the lower screen 9D is at the desired lower end, close to the clamps 7.

Such a position at the minimum height, i.e. at a height DAX no greater than 200 millimetres with respect to the upper face of the clamps, ensures that the string of shafts 6 is covered by the extensible screen 9 and that therefore it is inaccessible to the operator of the machine or to other people during all of the operative drilling steps. In such a position, it is therefore in safe conditions and the danger of parts of the body getting caught or making contact with the moving parts 6 involved in the drilling is eliminated.

Therefore, as long as the sensor detects the completely lowered position of the screen 9, the drilling machine 1 can work in normal operating mode allowing the rotation of the string 6 and the advancing of the rotary 5.

When the lower screen segment 9D is lifted, the sensor detects such movement and generates a control signal that directly, or for example through a suitable logic unit 17 (shown in Figure 1) immediately commands all the dangerous manoeuvres to stop, in particular at least the rotation of the shafts, so as to protect the well-being of the operator; after this the logic unit 17 can for example automatically command the passage to safe operation of the machine, or simply enable it, leaving it at the operator's discretion whether to manually command the passage to safe operation of the machine or to return to normal operation.

The sensor, fixed to the mast 3, can be of different types and can be installed in different positions of the machine, ensuring the same safety function. In a first mode of installation, the sensor is a microswitch or a proximity sensor fixed at a suitable height on the antenna 3 so as to be activated by an abutment part of the screen 9D, or rather by the slider unit 82A.

In a second mode of installation, the sensor can be an absolute encoder mounted on the rotary actuator 41 or 43 to read the rotations of the drum and thus derive the longitudinal position of the slider unit 82A and thus of the screen 9. After having done an initial zeroing of the encoder with the screen 9D in a known position, a control unit 17 (e.g. a PLC), knowing the primitive winding diameter of the cable/chain or the diameter of the pinion and knowing the revolutions of the rotary actuator, is able to calculate the exact position of the lower screen 9, and in particular of the lower part 9D and consequently can suitably activate or deactivate the limited operating mode. Other variants of the sensor, like those of the contactless type (for example laser and magnetic) are considered equivalent for the purpose.

Starting from the condition shown in Figure 2A or 3A, with rotary 5 lifted, screen 9 extended and drilling machine 1 positioned with antenna 3 aligned with the drilling axis, it is possible to start the drilling step. The screen 9 is in completely extended configuration and to the minimum height, therefore the sensor continues to give approval for use in normal operating mode for this entire step. The drilling is carried out by lowering the rotary 5 and the slider unit 82 and setting the string 6 in rotation.

During the descent of the rotary, the actuator 41, 43 of the screen is not actuated and therefore the lower screen 9D remains at a constant height with respect to the clamps 7. The upper and intermediate screen elements (9A, 9B and 9C) slide with synchronised movement with respect to the rotary 5, collapsing towards the lower part of the antenna 3 and reducing the overall length of the screen 9 to the minimum closure size.

The intermediate screen elements 9B and 9C progressively descend inside the lower element 9D and thanks to its lower lips that act as scrapers also carry out cleaning of the inner wall of the screen 9C. The screen 9B descends inside the screen 9C until it goes into mechanical abutment through suitable abutments. The screen segment 9A moves in the longitudinal direction to the antenna in a synchronised manner with the rotary 5 and with the slider unit 82.

Once the rotary has completed the entire stroke towards the base of the antenna 3, the end of advancing condition shown for example in Figure 9 is reached. In this condition the screen 9 is in completely contracted condition, enclosing most of the portion of the drilling string that is outside of the drilled hole and continuing to protect workers working around the machine.

The height (in the longitudinal direction to the antenna) of the screen elements 9A, 9B, 9C and 9D is suitably selected so that in this configuration, the presence of the screen 9 does not reduce the useful stroke of the rotary and does not obstruct its motion. Advantageously, the screen 9 can be installed on a machine that originally lacked it, without such installation reducing the stroke of the rotary.

The height of the screen elements sized in the manner just described implicitly determines the number of intermediate elements 9B, 9C necessary to allow a variation in length of the screen 9, between the completely contracted configuration and the completely extended configuration, equal to the stroke of the rotary 5. Typically values of such a height can vary between 0.5 metres and 1.5 metres.

Starting from the operative condition of Figure 2A or 3A, if the desired drilling height has been reached and it is not necessary to add shafts, it is possible to lift the rotary 5 so as to extract the shafts from the ground until it returns to the configuration of Figure 2. During the lifting of the rotary, the rotary actuator 41, 43 is not actuated to move the lower screen 9C. In this way, the lower element of the screen 9D remains at a constant height above the clamps 7 ensuring the protection of the shafts. The sensor detects the lowered position of the screen and maintains the normal operating mode.

Starting from the operating condition of Figure 2A or 3A, if the desired final drilling height has not been reached and it is therefore necessary to add shafts 6A, it is necessary to hold the shafts already inserted in the excavation through the clamps 7 and disconnect them from the rotary 5, unscrewing them. At this point it is possible to lift the rotary 5 advantageously also by activating the actuator 14 to make the lower screen segment 9D translate upwards.

The lifting of the lower screen 9D is detected by the sensor that is activated, thus sending off a command signal and can act directly on the actuators of the rotary 5 to immediately stop at least the rotation of the drilling string. Alternatively, when firstly the lifting of the slider unit 82 is completed and then the lower screen 9D is lifted by acting on the slider unit 82A, the sensor can simultaneously block both the rotation of the shafts and the axial sliding of the rotary 5 along the antenna.

In a variant, the command signal generated by the triggering of the sensor can be sent to a control unit 17 that as well as commanding at least the stopping of the rotation of the drilling string, can automatically manage multiple additional safety functions such as blocking the longitudinal sliding of the rotary 5 or emitting a sound or light warning signal; alternatively, the logic unit 17 can limit itself to enabling such additional safety functions, giving the possibility for an operator to activate them, or not, manually.

The screen 9D, while rising, progressively encapsulates the intermediate screens 9C and 9B. The lower screen 9D in its lower part is equipped with a horizontal edge that while rising progressively comes into contact with the lower edge of all of the intermediate and upper elements of the screen 9 pulling them up until the screen 9 is brought into the completely contracted condition 9' visible in Figure 4 whereas the edge with the upper segments resting on it is visible in Figure 10.

The lower edge of the screen 9D partially closes the lower face of the screen and has an opening of slightly larger diameter than that of the shaft 6. The lower edge thus acts as a screen against the debris rising from the excavation and at least partially obstructing the rise of the debris in the screen. Advantageously, the lower edge of the element 9D can be concave towards the base of the antenna.

The concave shape allows the debris and the debris to be reflected towards the base of the antenna and allows the radius of the area in which they fall to be limited. Once the collected configuration in an upper position has been reached, it is possible to load new shafts in the string 6, while the machine is in limited operating mode - also called, in the present description, "safety operating mode ", so as to be able to then proceed with the drilling up to a greater depth. Such loading can take place manually, or if the service winch is used with the cable 21, it is advantageous to laterally move the rotary 5 and the screen 9, to leave free passage along the mast 3, as shown in Figure 4A.

At least one linear actuator 11 driving the lateral or transversal movement of the rotary, in a rigid manner pulls the screen 9 that slides laterally and in a guided manner with respect to the slider unit 82A.

From Figures 4A and 4B it can be seen that the presence of the screen 9 does not increase the loading height of the shafts with respect to the ground. Since the two sliders 82 and 82A are close to one another, it is advantageously possible, in this close-together configuration, for the two sliders to couple by means of a mechanical abutment such as to allow the synchronous movement of the two sliders with a single actuation, through the actuator 11 or 11A.

Alternatively, the side displacement system can be actuated in a coordinated manner both by the actuator 11 and by the linear actuator 11A. The transversal movement can be required also to carry out a loading of the shaft 6A through the use of mechanized loading means installed on the machine 1 or through external mechanized loading means, which in some cases must be able to have free access over the entire front of the antenna 3 in order to be able to operate. When the rotary is in the transversally moved configuration the screen 9 can be lowered to protect a possible shaft 6 that is connected on the rotary.

In the case in which the shape of the screen is open on the antenna side, the simultaneous absence of the shaft 6 on the rotary and the lowering of the screen 9, allow the later be easily cleaned, in its inner wall. If the screen is of the type with section open towards the antenna (for example "C-shaped") when it is moved transversally, it would become accessible. Therefore, in some operating conditions in which it is required to make the shaft rotate, it could be necessary to fix on that same side, to the antenna 3, a protection, fixed or mobile, which closes the free side left by the screen. Variants of protection attached to the rotary, windable and retractable are considered totally equivalent for this purpose.

Once the final height of the excavation has been reached, it may be required to lower an armature 23, and in this case it will be hooked to the service cable 21 through the hook 22 and it will be lowered into the hole exploiting the lateral movement of the rotary and of the safety system 9.

Figure 5 shows the end of drilling configuration in which the rotary and the screen 9 are translated laterally without being lifted in height, to save time, particularly when the shafts 6 must be extracted from the hole using the service cable 21 or lifting means outside of the machine (used to remove many shafts together, without having to dismount them all).

Figure 6 again shows a first embodiment of the safety system described with a third variant of motorisation consisting of a linear actuator or cylinder 61 (hydraulic, electric or pneumatic) that moves the screen 9 through a cable relay system 62 and 64. The actuator is connected at the bottom to the lower screen 9C and at the top to the intermediate screen 9B. In the example given here, the stroke of the rotary is shorter or the length of the segments is greater and therefore the number of them necessary to cover the entire stroke, when completely extended, is less than those shown in Figure 2. Therefore, the distal element, in the case of Figure 6 is 9C, whereas in Figure 2 it was 9D.

The cable 62 is fixed at one end to the upper screen 9A and at the other end to the lower part of the lower screen 9C. The cable 64 is fixed at the top of the screen 9A or directly to the rotary 5 or to the slider 80 or furthermore to the slider unit 82, and at the other end to the upper part of the lower screen 9C. Passing from a completely extended configuration to one in which the actuator is retracted, the lower 9C and intermediate screen 9B are moved by cable relays 62 and 64 passing to the completely contracted configuration.

This solution makes it possible to contain the dimensions of a linear actuator by exploiting the cable relays to make it compatible with the length of the antenna. In the case of direct connection of a jack to the distal or lower screen 9C (or 9D), to the rotary 5 or to the carriage, the stroke of the actuator would have to be of many metres and consequently when it is in collected configuration 9', it will jut several metres above the rotary generating problems of bulk in height and impossibility of using it in confined spaces or for drilling inside buildings. Vice-versa if it were kept mounted flush at the top, it would not allow all of the screen to be compacted up to the contracted configuration 9' for which the free space left between the screen 9 and the clamps 7 is maximised. In the case illustrated in Figure 6 it is necessary to supply the jack with a hydraulic/pneumatic pipe or with flexible electric cables that generate a bag so as to compensate the movement of the jack 61 with respect to the mast 3.

Both in the case of Figure 6 and in the previous cases, it could be necessary to reduce the "catching" effect, i.e. momentary locking or jamming caused by misalignment, of the segments of the screen 9 moving with respect to one another. In this case, an alternative solution to the addition of further guides on the intermediate segments, could be to apply a system like an adjustable cable tensioner, belt tensioner or chain tensioner, so as to ensure that it is rectilinear.

A further and ninth embodiment, which provides for the side displacement of the rotary and of the screen, is visible in Figure 13. In the solution of Figure 13 the extensible screen 900, reversibly extendable and retractable along the guiding antenna 3, can consist of a single segment made with walls of a flexible or deformable material capable of shortening and lengthening longitudinally to its own axis and/or to the longitudinal axis of the drilling string when subjected to axial compression or traction.

Like in the embodiments of Figures 13A, 13B, 14A, 14B the extensible screen and in particular the single segment that forms it can shorten and lengthen substantially like a bellows.

Said single segment made of flexible or deformable material can thus pass from a contracted or collected configuration 900' (visible in Figure 13B) to an extended configuration 900 (visible in Figure 13A). Examples of walls of a flexible or deformable material can be a wall in metallic mesh, a fabric sock, a tubular sheath in plastic material or in rubber.

Said screen 900 comprises a proximal end 900A and a distal end 900B. The end 900A can be substantially similar to the upper end of the screen 9A of Figure 2, whereas the end 900B can be substantially similar to the lower end of the screen 9D of Figure 2, with the important difference that in the embodiment of Figure 13 the proximal end 900A and the distal end 900B belong to the same single segment of the screen 900. Preferably, the proximal end 900A of the screen 900 is fixed integrally to the rotary 5 or to the first slider unit 82 to follow in a synchronised manner at least the longitudinal sliding of the rotary along the guiding antenna 3.

The lower or distal end 900B of the screen 900 is preferably fixed to the second slider unit 82A and advantageously fixed to the fourth slider 80A. The second slider unit 82A or preferably the fourth slider 80A are equipped with a plate or frame 96 that extends in a direction perpendicular to the antenna extending around the drilling axis for a radial bulk at least equal to that of the screen 900. The plate 96 has a central hole with a sufficient diameter to allow the passage of the string of shafts 6 and the passage of drilling debris. Such a plate 96 is fixed to the distal end 900B of the screen 900.

In this way, it is possible to use the side displacement system 8 in the same way already described for the first embodiment already explained relative to Figures 2 and 4. The second slider unit 82A allows the lower section 900B of the screen 900 and the plate 96 to be kept coaxial with the upper rotary and thus with the drilling string 6, even when the rotary translates laterally with respect to the antenna 3, avoiding misalignments of the screen 900 on the plane perpendicular to the longitudinal axis of the antenna 3.

In the embodiment of Figure 13, fixed on the plate or frame 96 of the fourth slider unit there can be a plurality of winders 97, from each of which a cable 98 extends, which connects to the rotary 5 or to the first slider unit 82. Each winder 97 has a drum for accumulating cable and can be equipped with an inner spring, for example a coil spring, which allows the cable 98 to always be kept under tension. Possibly, the coil spring can be replaced by an electric or hydraulic motor that takes care of keeping the cable 98 under tension.

When the first and second slider unit 82 and 82A move axially apart, each winder 97 allows the unwinding or release of the cable 98. On the other hand, when the two slider units move together, each winder 97 recovers or rewinds the cable 98 and accumulates it in the drum. On the plate or frame 96 at least three winders are fixed, arranged so that the three cables 98, if observed in plan, are the same radial distance from the drilling axis, or rather are on a circle of smaller radius with respect to the radius of the screen 900, and arranged equally angularly spaced, or rather 120° apart from one another. It is also possible to fix many winders 97, for example four spaced apart by 90° or six spaced apart by 60° and so on.

It is thus possible to make a screen 900 with a substantially cylindrical shape with closed cross section, or alternatively with a substantially C-shaped cross section or in any case such as to contain and surround the drilling string 6. In the case in which the screen is made with a mesh or a fabric, the weft of such a mesh or fabric must be sufficiently dense, i.e. it must leave sufficiently small empty spaces, such as to prevent the entry of an operator's fingers but at the same time make it possible to see from the outside when the shafts are in rotation and the possibility of making material come out from inside (for example the drilling debris) or to allow easy cleaning from the outside.

In the case in which the screen 900 is made of rubber it can have a "bellows" shape so as to be able to vary its own length.

In the solution of Figure 13 the extensible screen 900 is mounted outside the cables 98, so that they keep it radially distanced from the string of shafts 6. In the condition with the screen extended, as shown in Figure 13A, it takes up an almost cylindrical shape with diameter not greater than the bulk of the rotary 5 but sufficiently large to encapsulate the cables 97 and the material from which such a screen is made takes up an almost rectilinear extended shape.

In addition it is also possible to mount a spiral or helix 99, for example formed from a metallic or plastic rod that winds up, forming coils that wind around the drilling axis so that each coil, if seen in plan, includes all of the cables 97 inside it and is externally tangent to the cables 97, still remaining inside the screen 900. The spiral 900 is thus arranged between the cables and the screen in a radial direction with respect to the axis of the shafts 6.

This elastic spiral 99 contributes to maintaining the desired shape of the screen, ensuring its distance from the shafts even when the antenna is laterally inclined. This spiral 99 can also be connected to the screen 900 by sliding inside through holes formed on the screen itself. The upper and lower end of the spiral 99 can be fixed, respectively, to the rotary 5 and to the plate 96. When the lower slider unit 82A moves towards the upper slider unit 82, the screen 900 behaves like a sleeve and tends to sag forming folds or creases that make it possible to accumulate the material of the screen in a contracted configuration 900' shown in Figure 13B.

The cables 97 ensure that such folds form towards the area outside the cables, thus further from the shafts 6. During the mutual approach of the lower and upper slider, the spiral 99 is compressed and reduces the pitch of its coils to take up a shorter configuration, whereas the cables 98, which are inside the spiral 99 prevent it from taking up a laterally deviated configuration.

A further and tenth embodiment is shown in Figure 14. The solution of Figure 14 again foresees an extensible screen 900^III, reversibly extendable and retractable along the guiding antenna 3, which can consist of a single segment made with flexible or deformable material that makes it possible to vary the longitudinal dimension of the screen when it is subjected to a force, of traction or of compression, in a direction parallel to the longitudinal axis of the drilling string.

Also in this case, the proximal end 900A is connected to the upper slider unit 82 and the distal end 900B is connected to the second slider unit 82A. The difference with respect to the solution of Figure 13 consists of the fact that now the winders 97 are arranged so that the cables 98 slide outside the screen 900 ^III, i.e. at a greater radial distance with respect to the drilling axis. In order to keep the screen 900 ^III guided the spiral 99 is no longer present but it is possible to use hoops 100.

These hoops 100 are substantially formed from a ring to which a plurality of guiding handles are fixed radially, arranged outside the ring itself. The ring of the hoop 100 has an inner diameter roughly corresponding to the diameter of the screen 900^III. A plurality of hoops 100 is fixed outside the screen 900^III at regular intervals along the axial dimension of the screen itself, for example gluing the rings of the hoops to the screen or making through hole on the screen inside which it is possible to pass the rings of the hoops 100.

Each hoop 100 has a number of handles equal to the number of cables 98 intended to be used, for example three, four or six. Each handle has a through hole inside which the cable 98 can be slidably inserted, so that the hoop can slide with respect to the cables.

When the screen 900^III is in extended configuration like in Figure 14A, the hoops are arranged perpendicular to the drilling axis, with the centre of the hoop positioned practically on the drilling axis, and they are kept in such a position thanks to the fact that they are guided on the cables 98 that in turn are arranged equally angularly spaced from the drilling axis. The hoops thus keep the screen distant from the shafts 6, even when the antenna 3 is inclined with respect to the vertical and give the screen itself a preferably cylindrical shape.

When the lower slider unit 82A moves towards the upper slider unit 82, the hoops 100 sliding along the cables 98 through their handles, move towards one another keeping the screen centred and coaxial to the shafts 6. The screen 900^III during this step behaves like a sleeve and tends to sag forming folds and creases that allow the material of the screen to accumulate in a contracted configuration 900' shown in Figure 14B.

Clearly, it would also be possible to fix the winders 97 to the upper slider unit 82 and connect the end of the cables 98 to the lower slider unit 82A without it modifying the operation of the screen system 900^III_.

A further and eleventh embodiment is shown in Figure 15. In the solution of Figure 15 the extensible screen 900^IV, reversibly extendable and retractable along the guiding antenna 3, consists of a single segment and in greater detail is made substantially as a coil spring. The coil springs preferably consist of a strip of harmonic steel that is wound around an axis creating concentric coils of increasing diameter, each of which partially covers the previous coil preferably also when the spring is in extended condition.

In this way, the spring takes up a cone shape with the walls completely closed, thanks to the juxtaposition of the various coils. The screen 900^IV therefore has a proximal end 900A with a greater diameter and a distal end 900B with a smaller diameter. The elasticity of the harmonic steel tends to keep the coils in extended position, as can be seen in Figure 15A, i.e. with the minimum axial juxtaposition and therefore with the maximum length of the spring.

The juxtaposition of the coils and the conical shape of the spring also ensures that the coils are mutually guided in one another maintaining the rectilinear configuration of the spring without the need for external guides. When the coil spring is compressed, the coils tend to slide with respect to one another in the axial direction, thanks to the fact that they have increasing diameters, increasing their axial juxtaposition and reducing the overall length of the spring.

During the variations in length the spring always maintains a closed and continuous perimetric shape. It is thus possible to mount the coil spring, which forms the screen 900^IV, in coaxial position to the drilling axis by selecting a minimum diameter of the spring that is such as to contain the shafts 6 and that allows the debris to be discharged and at the same time allows a maximum diameter of the spring to be selected that does not jut with respect to the bulk of the rotary 5.

Preferably, the proximal end 900A is connected to the rotary or to the upper slider unit 82 through a flange 100A that partially inserts in the spiral, whereas the distal end 900B is connected to the lower slider unit 82A through a flange 100B that partially inserts in the spiral. When the lower slider unit 82A comes towards the upper slider unit 82, the coil spring of the screen 900 compresses staying coaxial to the shafts 6 until it reaches a contracted configuration 900^IV', as shown in Figure 15B. The coil spring therefore prevents access to the shafts 6 during the work steps.

In the embodiments of Figures 13,14 and 15 the movement of the slider units 82 and 82 can take place with the same actuation systems already described relative to Figures 2 and 3.

Also in the embodiments of Figures 13,14 and 15, the safety system comprises a sensor that detects the position of the distal end 900B of the screen 900, in a totally analogous manner to what has already been described in the first embodiment. More specifically, such a sensor can detect the completely extended configuration of the screen 900, when the lower screen 900B is at the desired lower end, close to the clamps 7.

The use of a screen made with a single flexible element made from fabric or mesh has the advantage of being lighter with respect to a screen with multiple rigid segments, and this case promote the stability of the machine.

When the extensible screen comprises a single segment, like for example in the embodiments of Figures 13A, 13B, 14A, 14B, 15A, 15B, the latter in configuration of maximum extension has an overall length preferably equal to or greater than 2 metres, and preferably comprised between 2 metres and 10 metres, more preferably comprised between 2 metres and 8 metres or between 2-6 metres.

Figure 7 shows a second embodiment, also motorised like the second variant already described in Figure 3 and with the same modes of actuation, therefore we will not repeat it.

A difference with respect to the first embodiment described consists of the fact that the screen 90 instead of being laterally mobile like the screen 9, and in phase with the movement of the rotary 5 with respect to the first slider 81, as shown for example in Figures 4 and 5, it is again position so as to always contain the drilling string 6 and it is not equipped with this transversal translation movement.

Its shape is such as to contain the string of shafts 6 both when the rotary 5 is centred with respect to the drilling axis, and when it is in a laterally displaced position, being guided on the carriage 81. In this case the second slider unit 82A can comprise the third slider 81A, mounted so as to be able to slide along the guiding antenna 3 for example along suitable sliding guides, but lack the fourth slider 80A.

The screen 90 consists of a plurality of segments 90A, 90B, 90C, totally analogous to the corresponding ones 9A, 9B, 9C described in the previous Figures (wherein 90C, in this case being the lower screen, is comparable to 9D of Figures 2 to 5, and to 9C of Figure 6).

The upper screen 90A is advantageously fixed to the slider unit 82, or as described earlier it can be indirectly connected with flexible tensioning means that reach the screen 9A from the high position of the antenna 3 (thus capable of keeping the screen 9A always lifted and in the vicinity of the rotary, e.g. stopping on an abutment fixed to the rotary 5 or to the slider unit 82). In the more difficult case in which the upper screen 90A is fixed to the rotary 5 or to the slider 80, it must be an attachment capable of keeping the screen 90 suspended but at the same time of releasing the lateral movement of the rotary 5 with respect to the upper screen 90A, so as to allow the movement thereof.

The distal segment 90C, in this case the lower one, as already illustrated in the previous configuration will be guided to the mast 3 through a carriage 81A or more simply with at least one support arm among 92 and 93 (in Figure 7 both are represented) that are guided on the same guides 3A of the mast 3 on which the carriage 81 is also guided, or on additional guides 94 fixed to the sides of the mast 3.

The guides to the mast 3 can also be fixed on the intermediate elements, as shown in Figure 7 for the intermediate screen 90B. Advantageously the wire-like guide 91 will be positioned in the higher part of the screen so that when the screen 90 passes from the extended configuration 90 to the compressed configuration 90', the guides 91 go into a pack on the guides 92, optimising the minimum length in bulk totally closed. As previously, a sensor arranged at the base of the mast 3 notices the presence of the lower screen 90C and enables normal drilling so long as said screen is not lifted by a motor means.

Figure 8 shows a partial side and front section of said safety system in which the screen 90 surrounds on one side the drilling string 6 and on the opposite side it has an elongated shape so as to allow the lateral movement of the rotary 5 on the carriage 81.

More generally, the retractable screen 90, as shown in Figures 8A, 8B, 9, 10A, 10B, 11, 12, can have substantially elongated cross sections, preferably rectangular with semi-circular ends, i.e. with the so-called "obround" shape; in this case, the retractable screen 90 is longitudinally guided to the guiding antenna 3 so as not to be able to move perpendicularly or more generally transversally to the antenna 3, and only moves the rotating head 5 laterally.

Clearly, the elongated cross sections are advantageously oriented in the direction of the lateral movement FT1 of the rotary. Of course, said lateral movement of the rotary 5 is always represented in the Figures towards the left, but it is totally analogous to that to the right. In the detail of Figure 8A it is possible to see the lower attachment points 48 of the flexible elements forming part of the upper branch 44 to the lower screen 90C and the lower attachment point 49 of the lower branch 43 of the flexible element.

It is also visible the guide of the screen carried out through the guides 3A of the mast 3. Advantageously, the maximum external width at least of the proximal end or of the proximal segment 9A considered in the ideal plane passing through the axes of the antenna 3 and of the drilling string, is preferably no greater than the maximum external width of the rotating head 5 in the same ideal plane, so as to reduce the overall bulks of the screen 9 and increase the ease of manoeuvre of the machine 1 in small spaces.

Figure 9 shows the rotary 5 in an end of drilling configuration, with the screen 90 in compressed or collected configuration 90', at the base of the antenna close to the clamps 7.

Figure 10 shows the rotary 5 in a raised configuration, typically in the shaft loading step, with the screen 90 in compressed or collected configuration 90', at the top of the antenna. The loading can take place manually by inserting the shaft 6A beneath the screen since said screen 90 in contracted configuration 90' no longer hampers the shaft 6 that always remains connected (also called "balancing rod") to the rotary 5 and that is used to arrive between the two clamps 7. Basically, the screen 90' is not lower than the lower end of the "balancing rod". In this sense, the screen in contracted configuration 90' maximises the free space between the screen 9 and the clamps 7 or the ground.

Figure 11 shows the rotary 5 in a laterally decentred position, obtained by being guided to the carriage unit 82, in particular to the guides 83 of the first slider 81. The screen is in collected configuration 90' and both are arranged at the top of the antenna, or in any case in a raised position. In this case it is possible to use the service winch, moving the cable 21 to lift objects like for example armatures, substantially increasing ease of work and safety of the workers that add the shafts to the drilling string or remove them from it. Advantageously, the object will be lifted inside the most inner screen, i.e. 90A, so as to also exploit the internal space of the screens as loading length, in an analogous manner to what was explained for Figure 4B.

Figure 12 shows the second embodiment, motorised like the first variant already described in Figure 2 and with the same modes of actuation, therefore we will not repeat them.

A further advantage of the extensible screens described previously is that they do not have to be dismounted from the guiding antenna 3 to move the rotating head 5 from the drilling axis allowing a substantial saving of time, for example to pass from the drilling steps to those in which the winch 21 needs to be used or in any case shafts need to be added or removed from the drilling string.

The examples embodiments described previously can undergo different modifications and variations without departing from the scope of protection of the present invention. For example, the extensible screen can have cross sections not only closed but also open, for example C-shaped or U-shaped in a manner to still enclose the drilling string. Moreover, all of the details can be replaced by technically equivalent elements.

it is possible to add elements outside of those present to increase the stroke of the rotary that in certain cases it is necessary to increase. In this case, a slider unit 82A can be adapted to continue to be guided on the antenna and at the same time connect to the distal segment added. The distal segment added could itself contain the guide elements and perform the function of the slider 82A. The actuation command with which the distal element of the screen 9 is motorised can also be carried out manually when the weight of the screen (due to small dimensions in sections, due to short strokes, due to use of light materials) is very low, e.g. less than 20kg.

The presence of the screens does not preclude that the machine also has additional safety devices installed, like for example one or more emergency cables arranged laterally on the antenna, or one or more emergency buttons or furthermore sensitive devices (actuated by radio, photosensitive, optical, laser, etc.). In the case of double-head drillings with shafts and tubes, in which the following are provided: a lower rotary that supplies the rotation of an outer tube coaxial to the inner shaft, in this case moved by an upper rotary, it should be understood that the safety system applies to the same extent as described up to now, between the lower rotary (of the tube) and the clamps.

The two rotaries present can be fixed together (for example mounted on the same carriage unit 82A or on the same second slider 80), and therefore the possible protection of the shaft coming out from the upper rotary up to the lower rotary can be achieved with a fixed screen. If, on the other hand, the two rotaries are mounted longitudinally sliding with respect to one another (generally with distances up to 1 meter and axial actuations along the axis of the drilling string - here meaning the group of shafts and tubes - that are made with jacks) then the protection system can be made with extensible screens also between the two rotaries.

In the particular case in which the two rotaries are longitudinally movable with respect to one another with longitudinal moving means of the independent type for the entire stroke, then the extensible screen can be advantageously applied also between the two rotaries.

The materials used, as well as the sizes, cam ne whatever depending on the technical requirements. It should be understood that an expression of the type "A comprises B, C, D" or "A is formed from B, C, D" also comprises and describes the particular case in which "A consists of B, C, D". The examples and lists of possible variants of the present application should be considered non-exhaustive lists.