Abstract:
A modular system of multipurpose rods for drilling soil is constituted by rods ( 1 ) crossed by an internal passage ( 2 ) for the passage of concrete, of substantially cylindrical shape, that completely crosses the rod; each of the rods is provided at the endings with a male insert ( 5 ) and a female insert ( 6 ) respectively, adapted to be plugged in one to the other for permitting the assembly in batteries of any length. The inserts ( 5, 6 ) are provided with transmitters ( 11, 11   a ) for transmitting the rotation along the whole battery of rods ( 1 ) and arranged for fixing elements that reduce the internal passage ( 2 ).

Description:
This application is a National Stage Application of PCT/EP2010/002806, filed 7 May 2010, which claims benefit of Serial No. TO2009A000394, filed 26 May 2009 in Italy and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
     BACKGROUND 
     The present invention takes its place in the field of mixing, consolidation and compaction technologies and concerns a modular system of multipurpose rods for drilling soils. 
     Various procedures are known for the consolidation of the soil through the formation of cylindrical columns of consolidated soil, based on the mixing of particles of the soil itself with binders, usually cemented mixtures. 
     A traditional procedure, through which a mainly mechanic mixing is carried out, uses the rotating movement of tools (see  FIG. 1 ) able to dig and breaks up the soil through appendixes which radially extend to the axis of the tool itself. The soil so broken up is kneaded with a low-pressure (1-2 MPa) cemented mixture pumped through openings obtained on the tubular shaft right under the blades. 
     A known variant of the described procedure is to use higher pressures for the cemented mixtures. This technique, by using the combination of the mechanical action of the disintegrating gears of the tool and of the kinetic energy of the pressurized jets, differs for a substantial execution speed, with considerable economic advantages. 
     There are variants of these techniques which require a double line of cemented mixtures. In addition to the outputs on the shaft of the tool which interact with the disintegrating gears, there are others on the upper parts of the blades which treat a diameter of soil bigger than the one treated by the mechanical disintegrating gears. This increase of the treated diameter when it is not requested for all the depth, makes it necessary a double supply. 
     Another technology taken into consideration by the present invention is the one of compacting piles. From the European patent EP 0 228 138 it is known an excavation and compaction equipment for the construction of compacting piles. In this technology, during the excavation phase, the equipment undergoes a torque on the drill rod and a thrust on the excavation screw relatively elevated as the quantity of soil to be compacted during the excavation by the displacer element ( FIG. 2 ) is of significant relevance and exerts also a strong resistance to the advancement of the tool in the soil itself. During the ascent, the excavation is filled by means of injection of concrete which passes through the rods and the tool itself. 
     The document U.S. Pat. No. 7,494,299 describes an equipment provided with screw tool to which a plurality of hollow, extended and substantially cylindrical shaped rods is applied. 
     The rods are provided with special endings adapted to vertically connect them. The inner of the rods is destined to be filled with concrete at the end of the anchoring procedures which provide that the rods themselves are disposable as reinforcing structural elements. 
     However, the internal passage of the rods is not cylindrical and reduces in correspondence with the endings provided with particular inserts for the assembly of the rods themselves. 
     Furthermore, the rods are designed for carrying inner elements adapted for realizing the rotation which reduce the internal passage but only in correspondence of said endings. 
     SUMMARY 
     The invention refers to a modular system of multipurpose rods for drilling soils which, opportunely assembled, permits the use of the described technologies of soil treatment without having to assemble one specific for each use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The equipment will be now described in some forms of embodiment by way of example according to the invention with reference to the attached drawings which show: 
         FIG. 1  shows a prior art rotating system; 
         FIG. 2  shows a prior art compacting system; 
       In  FIG. 3  an axonometric projection of the part of the structural rod and common to different applicative technologies; 
         FIG. 4  shows the rod of  FIG. 3  in longitudinal section; 
         FIG. 5  shows the section according to the V-V trace of  FIG. 4 ; 
         FIGS. 6 ,  7  and  8  shows the rod of the preceding figures in three different types of embodiments; 
         FIGS. 9 and 10  shows partial perspective views in longitudinal section of the two portions of pipe endings according to the invention in the form of embodiment shown in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     Rod  1  according to the invention, visible in  FIGS. 3 ,  4  and  5 , is a modular rod provided with internal passage  2  created by an inner pipe  1 ′ which guarantees the continuity of the internal passage, through a cylindrical shape constant for all the length, which permits an optimal runoff of the injected material and which contributes to the tensile structure by collaborating to the most external pipe  1 ″ of rod  1 , and provided at endings with a male insert  5  and a female insert  6  adapted to plug in one another in order to permit the assembly in batteries of desired lengths. The constant section of the internal passage avoids speed variations and material stagnations caused by the slowdowns in proximity of zones enlarged with respect to other narrower ones. The inserts are provided with polygonal zones  11  and  11   a  adapted to plug in one another (insertable the one in the other for a coupling length equal to at least one time the diameter) for permitting the torque transmission along the whole battery. 
     Furthermore, male insert  5  is provided with centering zones  7  and  8  compatible with respective zones  7   a  and  8   a  of female insert  6  and can be provided with respective gaskets  9  and  10 . 
     The double centering guarantees the perfect alignment among adjacent elements of rods, necessary for permitting the correct functioning of the gaskets subject to pressure. A unique coupling could anyhow work but it would be much more axially extended and would have therefore a higher realization cost and would require a higher difficulty of insertion during the assembly. 
     Gasket  10  on the end avoids the leakage of the compacting mixture and at the same time prevents external agents from penetrating as far as internal passage  2 . Gasket  9  has the function of protecting polygonal coupling  11  and  11   a  from the inlet of external agents (water, soil, mixing, and so on) which could make the disassembly of the rods difficult. 
     In inserts  5  and  6  there are spaces  13  and  13   a  for the assembly of pins  12  for holding the rods among them. In  FIG. 5  it may be noticed that pins  12  are assembled with an axis mainly transversal with respect to the longitudinal direction of the rod and does not encumber further than the external diameter of the rods allowing the possibility of externally guiding the rod, during the excavation steps, without encountering discontinuities. 
       FIG. 6  shows the section of a rod according to the invention, wherein internal passage  2  is about 4″-6″, preferably 5″, adapted for the use for compacted piles, and with a seal collar  3  mounted on male insert  5  through a prearrangement that advantageously uses screws  4  for fixing. In order to avoid the leakage of the concrete during the injection, a gasket  14 , mounted on seal collar  3 , strikes in a zone  15  of female insert  6 . 
       FIG. 7  shows a section of the rod assembled with the insertion of a pipe  17  which creates in its inner side a passage  16  of about 50-75 mm, preferably 2″¾ (about 70 mm), suitable for the realization of cylindrical columns of compacted ground. On female insert  6  of rod  1 , described in  FIG. 4 , is screwed pipe  17  for the passage of the cemented mixture with flange terminal  18 ; on the opposite side, upon male insert  5 , a flange  20  guarantees the centering between pipe  17  and rod  1 , using the same prearrangements described for seal collar  3 . 
     In segment  17   a  of pipe  17  which exceeds male insert  5  are obtained seats for gaskets  19  which, striking on zone  21  of pipe  17  on the side of female insert  6 , can bear pressures up to 500 bar. Higher pressures require structural precautions and opportune choices of the most appropriate set of gaskets, with consequent cost increases. 
     In  FIG. 8  there is a section of rod  1  assembled for a double passage of fluids. On the rod described in  FIG. 4  is screwed into female insert  6  an element  30  constituted by two concentric pipes  22  and  22 ′ for providing an annular passage  22 ″ of the cemented mixtures, and provided with flange terminal  23  which fixes in the same prearrangement present on female insert  6  of rod  1  upon which, as previously described, it has been fixed flange  18 ; on the opposite side, on male insert  5 , a flange  24  guarantees the centering between pipe  22  and rod  1  and it is also fixed using the prearrangements present on male insert  5 , upon which as previously described are fixed seal collar  3  and flange  24 . 
     In segment  22   a  of pipe  22 ′ which exceeds centering flange  24  of male insert  5 , are obtained seats for gaskets  25  which, finding strike upon zone  26  on the side of female insert  6 , can bear pressures up to 500 bar. 
     In  FIG. 9  there is the upper part of the embodiment of  FIG. 8  so that it is possible to detect that flange  23  is provided with passages  29  for not completely obstructing annular passage  22 ″ between pipes  22  and  22 ′ and leaving suitable structural strength to the part. 
       FIG. 10  shows the zone of the male insert embodiment of  FIG. 8  where protruding ending  22   a  of the pipe for the central passage is kept at the center of the pipe for annular passage  22 ″ by a support  27  which leaves free some perimeter areas. 
     An elastic ring  28  holds centering support  27  and prevents its extraction by means of the stair obtained through the processing on segment  22   a  for the external centering of central pipe  22 ′. 
     It is finally clear that to the device up to here described can be applied some variants, changes or adaptations without exiting from the protection field of the claims of the present invention. For example, it is clear that the preferred connection system among the different reference flanges described ( 3 ,  18 ,  20 ,  24 ,  23 ,  27 ) through screws, can be replaced by alternative systems (such as for instance threadings, interference mountings, bayonet coupling, glueings) which can be advantageously used as they are equivalent. The solution with screw coupling permits a maneuvering easiness during the mounting steps of the different variants and guarantees with opportune reference shoulders a perfect centering between the coupled parts which render it preferable with respect to the other systems previously described. 
     By means of the solution proposed by the invention, the use of a unique external structural rod opportunely arranged for the various kinds of ground treatment technologies brings to a reduction of the storage with consequent cost reduction. 
     Furthermore, the assemblies for the various technologies are of easy and rapid mounting and removal encouraging the flexibility and the maintenance. 
     Finally, given that the single or two-passages inner rods are wear components, in the solution according to the invention they are easily replaceable, and therefore the recovery in the construction site is immediate, using again the same structural body. 
     Rod  1  common to different technologies is the structural part for which the inner elements can be advantageously sized only for bearing the inner pressures and for being adequately fixed and centered with respect to rod  1 .