FIELD OF THE INVENTION

The present invention concerns a perfected drilling head, to be used for example in operating machines such as boring machines, drilling machines or suchlike.

BACKGROUND OF THE INVENTION

Drilling heads, as is known, are used to make holes in the ground, whether it be heterogeneous or rocky. The holes are used, for example, to obtain seatings in which to make piling, anchoring or other.

A known drilling head typically has a perforating rod which is equipped at the front with means able to perform the excavation on the specific ground.

The perforating rod, which can be axially perforated, is driven in rotation by drive means provided in a perforation unit, to which it is connected on each occasion.

Often, the perforation is such that the debris of the excavation has to be evacuated. Furthermore, sometimes, the walls of the excavation are stabilized using suitable perforation muds.

Depending on the type of excavation that is being carried out, three basic perforation methods have been perfected: direct circulation perforation; reverse circulation perforation and reverse circulation perforation with mud to stabilize the wall.

In these perforation modes, the perforating rod sometimes has a double wall as well as being perforated. Mud and debris are often expelled from above.

The expulsion of debris and mud must normally be compartmentalized in order not to generate operational difficulties for those who are working, and so as not to scatter everything everywhere.

In the state of the art, for a long time it has been widely provided that the zone surrounding the perforating rod is delimited by circumferential or tubular protective means, preferably bellows, or equipped with other means which are adapted to vary the longitudinal extension of the circumferential protection means.

The bellows means, in the upper part, are normally integrated with a support of the drilling head by means of a plate attached to said support.

The protection means with bellows anchored to the perforation unit are simple to manufacture, however they have various limitations, such as for example a big axial bulk, both in the closed position and also in the extended position.

Furthermore, the fact that the bellows protection means are stably anchored to the drilling head can generate high tensions on the protection means themselves, which tend to stretch excessively.

Furthermore, debris tends to accumulate in the upper part of the protection means, where the bellows are stably anchored to the drilling head.

There is therefore a need to perfect a drilling head which can overcome at least one of the disadvantages of the state of the art.

In particular, one purpose of the present invention is to provide a drilling head equipped with protection means which nevertheless has high protection efficacy against the projection of mud and debris consequent to excavation.

Another purpose of the present invention is to provide a drilling head which has tubular protection means which allow a greater extension or length of protection, given the same travel of the perforating rod and which also supply a greater residual space in the lower zone of the perforation unit, useful for connecting rods or perforation elements of variable length and in an easier way compared with known drilling heads.

Another purpose is to provide a drilling head which is provided with tubular protection means which can better withstand axial forces during the extension and retraction operations, and in which the possible deposit of dirt or debris, especially in the upper zone, is advantageously limited.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

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

In accordance with the above purposes, a drilling head according to the invention comprises a perforation unit provided with a rotation shaft carrying at least one attachment to which at least one drilling rod is connectable, and tubular protection means able to be positioned around at least part of the drilling rod and able to be extended or retracted by means of corresponding drive means.

According to one aspect of the invention, the tubular protection means are connected to the perforation unit by connection means mobile at least along a longitudinal axis with respect to the perforation unit, so that an upper part of the tubular protection means, that is, a part facing toward the perforation unit, can perform at least one axial movement along the longitudinal axis of the drilling head.

Advantageously, by means of the mobile connection means, it is possible to allow a certain axial movement of the upper part of the tubular protection means with respect to the perforation unit, this mainly allows to have a greater protection extension for the same extension travel of the tubular protection means, in the working situation of the drilling head, and a greater compactness of the drilling head in the inactive situation, that is, in the retracted situation of the tubular protection means, since it is possible to take their upper part closer to the perforation unit.

Furthermore, under the perforation unit, that is, in correspondence with the attachment of the drilling rod, in the inactive situation with the tubular protection means retracted, a large free space is left, useful to allow ample maneuverability for the installation also of drilling rods of different types.

According to other aspects of the invention, the mobile connection means comprise at least one mobile plate slidable along guide elements associated with the perforation unit.

In some embodiments, the present drilling head comprises elastic means interposed between the mobile plate and the perforation unit.

The guide elements can also be provided with at least one end of travel element able to limit the movement of the mobile plate when the tubular protection means are extended by means of the drive means.

Furthermore, the guide elements can be positioned in through holes made on the mobile plate.

In some embodiments, the guide elements and the elastic means can be positioned at intervals one from the others in the proximity of the periphery of the mobile plate.

According to other aspects of the invention, the mobile plate is annular- shaped and comprises a through hole able to slide with respect to a central body of the perforation unit.

In some embodiments, the tubular protection means can comprise a flange connected by means of attachment elements to the mobile plate.

In some embodiments, the drive means can be connected by means of a connection unit to a base plate of the tubular protection means.

The drive means can also comprise at least one cylinder driven hydraulically or pneumatically and provided with at least one guide element slidable with respect to the cylinder and connected to the tubular protection means.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a schematic longitudinal section view of a drilling head according to the present invention provided with tubular protection means in a first retracted position;

- fig. 2 is a schematic view of the present drilling head with the tubular protection means in a second extended position;

- fig. 3 is an enlarged view of a detail of the drilling head.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

We will now refer in detail to the various embodiments of the invention, of which one or more examples are shown in the attached drawings. Each example is supplied by way of illustration of the invention and shall not be understood as a limitation thereof. For example, the characteristics shown or described insomuch as they are part of one embodiment can be adopted on, or in association with, other embodiments to produce another embodiment. It is understood that the present invention shall include all such modifications and variants.

Before describing these embodiments, we must also clarify that the present description is not limited in its application to details of the construction and disposition of the components as described in the following description using the attached drawings. The present description can provide other embodiments and can be obtained or executed in various other ways. We must also clarify that the phraseology and terminology used here is for the purposes of description only, and cannot be considered as limitative.

With reference to the attached drawings, see for example fig. 1, a drilling head 10 according to the present invention comprises a perforation unit 11 provided with a rotation shaft 12 carrying at least one attachment 13 to which at least one drilling rod 14 is connectable.

The rotation shaft 12 will be able to rotate around a longitudinal axis L of the drilling head 10, and will be driven by any suitable drive means provided in the perforation unit 11.

The drilling head 10 comprises tubular protection means 15 able to be positioned around at least part of said drilling rod 14. Such tubular protection means 15 can be bellows means, telescopic means with several extensions, or other, and can be extended, as in fig. 2, or retracted, as in fig. 1, by drive means 16 which regulate their extension. If the tubular protection means 15 are bellows means, as shown as a non-limiting example in the drawings, such means can be made of rubber or suchlike.

The tubular protection means 15 are connected to the perforation unit 11 by means of connection means mobile at least along a longitudinal axis L with respect to said perforation unit 11, so that an upper part 19 of the tubular protection means 15, that is, a part facing toward the perforation unit 1 1, can perform at least one axial movement along the longitudinal axis L of the drilling head with respect to the perforation unit 11.

The connection means comprise at least one mobile plate 17 slidable along guide elements 21 which are associated with the perforation unit 11. Such guide elements 21 are suitable to allow the axial movement along the longitudinal axis L of the mobile plate 17, therefore they will be directed parallel to the longitudinal axis L. The present drilling head 10 can comprise elastic means 18 interposed between the mobile plate 17 and the perforation unit 11.

The elastic means 18 can be connected to the mobile plate 17 and to a plate 20 integral with the perforation unit 11.

The drilling head 10 comprises guide elements 21 able to guide the mobile plate 17 in the axial movement and which are provided with at least one end of travel element 22, able to limit the downward movement of the mobile plate 17, that is, towards the excavation zone.

The end of travel elements 22 could also be provided for the elastic means 18, which would therefore comprise, centrally, an element which goes beyond the mobile plate 17, similarly to the guide elements 21.

The guide elements 21 are disposed in parallel directions to each other and to the longitudinal axis L of the drilling head 10.

Substantially, in the situation of fig. 1, the elastic means 18 are compressed by means of the drive means 16 and keep the mobile plate 17 raised with respect to the end of travel elements 22.

In the situation of fig. 2, which can be considered as an operating situation of excavation, the mobile plate 17 is, for example, abutting against the end of travel elements 22.

For example, it can be assumed that in the situation of fig. 2, that is, when the mobile plate 17 is abutting against the end of travel elements 22, the elastic means 18 are in an inactive situation, while in fig. 1 they were compressed. However, it is also possible to provide that such elastic means 18 are still partly compressed even when the mobile plate 17 is abutting against the end of travel elements 22, as in fig. 2.

Furthermore, it would also be possible to provide a degree of pre-stressing of the elastic means 18 also in the situation of fig. 1, that is, the possibility of keeping the mobile plate 17 raised with respect to the end of travel elements 22 even without the aid of the drive means 16.

Naturally, in the functioning of the present drilling head 10, the mobile plate 17 can be positioned in intermediate positions with respect to those shown in fig. 1 and fig. 2.

In some embodiments, the guide elements 21 are disposed in the proximity of the periphery of the mobile plate 17.

The guide elements 21, which are attached at the upper part to the plate 20 which is integral with the perforation unit 11, are inserted in through holes 24 made on the mobile plate 17, see in particular fig. 3.

The elastic means 18 can also be disposed in the proximity of the periphery of the mobile plate 17, for example at intervals with the guide elements 21, so as to confer optimal balance on the axial movement of the mobile plate 17 and of the upper part 19 of the tubular protection means 15. Substantially, therefore, the guide elements 21 and the elastic means 18, disposed at intervals with respect to each other, are positioned according to an annular configuration in the proximity of the periphery of the mobile plate 17.

The mobile plate 17 can be annular- shaped and comprise a through hole 32, in particular a central hole, able to slide axially with respect to a central body 23 of the perforation unit 11.

The tubular protection means 15 comprise in the upper part 19 a flange 25 which is connected by means of attachment elements 26 to the mobile plate 17.

As stated, the tubular protection means 15 are provided with drive means 16, for example a hydraulic, pneumatic or other actuator, configured to allow the extension and retraction of the tubular protection means along the longitudinal axis L.

The drive means 16 can comprise a cylinder 27, for example attached to the perforation unit 11 by means of suitable supports 28, and a guide element 29 mobile with respect to the cylinder 27, in particular in a direction parallel to the longitudinal axis L.

The guide element 29 is attached to a base plate 31 of the tubular protection means 15 by means of a connection unit 30.

As can be seen in fig. 1, a wide free space S is made in correspondence with the attachment 13, for the attachment of the drilling rod 14.

The mobility of the upper part 19 of the tubular protection means 15 with respect to the perforation unit 11 allows to have the following improvements: the drilling head 10 is more compact, therefore with the same travel of the drilling rod 14 there is more residual space under the perforation unit 11, the attachment 13 can be used to load drilling rods or elements more easily, or load longer ones; see for example fig. 1 in which the mobile plate 17 is raised following the action of the drive means 16;

the possibility of extending the protection is increased, keeping the same minimum size at the upper end of travel. With the same type of tubular protection means 15, it is possible to cover a longer length by means of the longer drive means 16, for example hydraulic cylinder;

the present drilling head 10 protects a greater length along the longitudinal axis L, preventing debris from projecting;

if present, the elastic means 18 compress due to the thrust of the drive means 16, with the result that the mobile plate 17 moves closer to the perforation unit 11 , which means less bulk and greater compactness when the guide element 29 slidable with respect to the cylinder 27 is in a retracted position;

in the extension of the guide element 29, the elastic means 18 thrust the mobile plate 17 away from the perforation unit 11 and therefore the guide element 29 can allow a greater travel, and in an extended position, fig. 2, the tubular protection means 15 cover a longer part, improving the debris containment effect.

The present solution also allows to provide solutions for the connection of rods and/or tubular protection means of different lengths, and also to apply the same system on perforation units of different sizes.

The mobile plate 17 also has a scraping effect on the upper part of the tubular protection means 15, where it is widely known that dirt and/or debris tend to accumulate.

The present solution allows to better absorb the axial stresses of the tubular protection means 15, in particular in the case of bellows means.

If material stops or deposits on the tubular protection means 15, when it is compacted, the upper travel of the mobile plate 17 allows a greater travel; this prevents the rubber from being damaged due to crushing, for example with stuck debris. It should be considered that if it is not washed correctly, accumulations of materials such as cement and/or perforation material may occur. The elastic means 18, if present, allow the compression.

The elastic means 18 offer a greater guarantee on the return to position of the tubular protection means 15, in the event that there is excessive friction between the mobile parts, for example between the mobile plate 17 and the central body 23 of the perforation unit 11.

It is clear that modifications and/or additions of parts may be made to the drilling head as described heretofore, without departing from the field and scope of the present invention.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of drilling head, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

In the following claims, the sole purpose of the references in brackets is to facilitate reading: they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.