Patent Publication Number: US-6655474-B1

Title: Drill for making wide diameter and high depth holes and method for carrying out said holes

Description:
TECHNICAL FIELD 
     The invention relates to a drill fit for carrying out wide diameter and high depth holes, especially for pilings and wells, and method for carrying out thereof. 
     BACKGROUND ART 
     Document U.S. Pat. No. 2,910,274 discloses a drill for digging holes for pouring bell-shaped footings having a motor rigidly fixed to the lower and of an upper column member. The motor is connected by means of pinions to a lower column member and axially rotates the lower column member with respect to the upper column member. 
     The drill includes an hydraulic fed linked to the motor. The whole column assembly, including column members and motor, is shifted vertically by means of a cable wound up on a reel of a crane and fixed to an arm of a boom engaging pulleys associated to the rigid connection between motor and upper column member. 
     A carrier canister is fixed to the lower and of the lower column member and has, at list at its free and, a digging tool. A support assembly of the canister reciprocates along lower column member, by means of an hydraulic actuator, to open and close the carrier canister. 
     The main drawbacks of this known drill consist in that, because of the column members, it cannot carry out high depth holes and, because or the fixed connection between the canister and the lower and of the lower column member, the digging phase must be stopped in correspondence of the descending, unloading and lifting of the canister. 
     The piles for the soil consolidation are commonly realized during the drilling phase, the reinforcement bar installation and concrete casting. The drillings are carried out by means of soil cutting or crumbling and carrying away the removed material. 
     Currently the material removing is done by means of either intermittent transport, using hammer grabs or a telescopic Kelly driven by a rotary, that must be lifted each time, or continuous transport by means of a cochlea or by fluid circulation. 
     The hammer grab utilization is limited to the scarce cohesion grounds, particularly to transport material trough the casing pipes. 
     Using the rotary with telescopic Kelly system is possible to make holes for wide diameter piles (up to 2-3 meters) but for limited depth, typically 50-60 m. The depth limit is due to the fact that the cutting and material transport tool is linked to the inferior end of series of telescopic stem fit to transmit the cutting torque. With the hole depth increasing, the stem length or the number of the used clements must increase with difficulties imposing the cited limits. 
     Increasing the diameter, the resistance of said elements must be also increased. So the wide diameter and high depth holes can be obtained only with very high, heavy and expensive machines that sometimes don&#39;t have the required space to operate. 
     With the cochlea system, it is used an helix with the sharp tools in the inferior part, linked in the upper part to a rotary that drive the rotating movement and to extraction wire ropes. Said method requires high extraction forces and very high machines, whose height is comparable to the hole depth. Practically holes with 1,2-1,5 m as maximum diameter and 25-30 m as maximum depth are possible. 
     The circulating fluid systems require water pumps, or air compressors with flows growing with the diameter and depth increasing. Said systems allow to reach very high depth only if the working diameters are small (200-300 mm). Wider diameter holes (800-1400 mm) would be done using great flow rates required to the crumbled material lifting. 
     The reverse circulation system allows to drill deep and large diameter holes lifting the cut or crumbled material in a stream of water moved upward inside the stem by compressed air. This system can be used only in waterproof soil, or on the sea or lakes or making the hole waterproof thanks to expensive casings. 
     DISCLOSURE OF THE INVENTION 
     An object of the present invention is to allow the carrying out of great diameter and high depth holes, for pilings or wells with an equipment limited in height, weight and cost, usable also under bridges, tunnels, buildings near electric cables, in lakes and in the sea. 
     Another object is to hardly increase the hole execution speed. 
     According to the method and the machine of the present invention, the drilled material is carried to the surface by a carrier canister or similar that slides along the drill stems rotated by a rotary, being linked to ropes moved by winches rotating integral with the stems. So the material can be quickly and continuously removed, without lifting and moving the stems and without necessarily stopping the drilling operations. 
     The above described objects are obtained in accordance with the content of the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is now described, referring to the enclosed drawings that show as sample some possible embodiments, in which: 
     FIG. 1 shows a schematic side view of the operating drill, with the carrier canister during the lifting phase; 
     FIGS. 2 and 3 show respectively a side and a cross sectional view of a device for hooking the carrier canister the stems, in the releasing condition, with the free sliding of the carrier canister; 
     FIGS. 4 and 5 show the same particulars of FIGS. 2 and 3, in the hooking condition; 
     FIGS. 6 and 7 show two schematic side views of the drill equipped with a piston carrier canister, during two different working phases; 
     FIG. 8 shows a schematic side view of the working drill, equipped with a down hole-hammer and linked to a compressor; 
     FIG. 9 shows a variant of the drill of FIG. 1 used for making high depth and wide diameter holes. 
    
    
     BEST MODE OF CARRYING OUT THE INVENTION 
     In FIG. 1, numeral  1  shows a basic machine that supplies hydraulic power to the rotary  2 , and, by means of an hydraulic joint  3 , to the winches  4 , that rotate integral with the drill stems  7  having a plurality of longitudinal projecting guides  19 . The numeral  5  show the carrier canister that is driven in the vertical movements by wire ropes  18  of the winches  4 . 
     The numeral  6  indicates the drill tool, linked to the stem  7  inferior end. The penetration and extraction force is driven from the translation cylinders  8  of the rotary to the drill tool  6  by means of the stems  7  with a stem clamp  9 . 
     The numeral  10  shows an auxiliary clamp that allows the stem holding during the extraction phase to facilitate the disassembling of this latter. The drill stems  7  are loaded by a loader  11  and connected by a device  12 . The numeral  13  shows a conveyor for moving the removed material. 
     In FIGS. 2,  3 ,  4  and  5 , the numeral  5 ′ refers to an inner sleeve of the canister  5 , provided with longitudinal grooves  21  of different width forming a shoulder  20 . 
     The drilling material can be continuously carried to the surface, without stopping the drill and without lifting the stems, by means of the carrier canister  5  sliding on the drill stem  7 , pulled by the wire ropes  18  linked to the winches  4  rotating integral with the stems. 
     To keep the carrier canister  5  down during the loading phase and to release it during the unloading phase, the automatic hooking device comprises the inner sleeve  5 ′. The inferior ends of the longitudinal projecting guides  19  can engage the shoulder  20  obtained by the longitudinal grooves  21 . 
     At the end of the descendant run, the carrier canister  5  reaches the soil removed by the drill tool  6  during the ascendant, unload and descendant phases of the canister  5 . To carry out the connection between the canister  5  and the stem inferior end, the stem clamp  9  clamps the stems  7  to the rotary  2  that is lifted by means of the translation cylinder  8 , until the wire ropes  18  are loosed showing that the canister  5  is properly lifted by the drill tool  6 . The rotary  2  rotates the drill stem  7  in the drilling rotation sense causing the overlay of the lower end of the longitudinal guides  19  on the shoulder  20  causing the automatic linkage between the stem  7  and the inner sleeve  5 ′ of the canister  5 . The above mentioned rotation in combination with a downward translation causes the opening of axial or radial valves, known and not illustrated, of the canister bottom that, consequently, can collect the removed soil. 
     In the hooking condition A of the canister  5  to the stem  7  by means of the inner sleeve  5 ′, the canister  5  rotates integral with the stems  7 . The canister  5  can be equipped with bottom drill tools such as drilling teeth  22  that, because of rotation, digs the soil together with the drill tool  6 , consequently the diameter of the hole can be wider than the diameter of the drill tool  6  and equal to the diameter of the canister  5 . 
     In the variant according to FIGS. 6 and 7, the carrier canister  5  has an inner piston  14  sliding inside the canister  5  and connected to the wire ropes  18  that facilitates the loading. 
     The piston  14 , when is pulled by the wire ropes  18 , intakes the removed soil inside the canister  5 . 
     In this variant the drill tool  6  has the same diameter of the canister  5  that, consequently, is not equipped with bottom drill tools. 
     In the variant of the drill according to FIG. 8 the numeral  16  indicates a joint connecting the stem bore to the outlet pipeline of an air compressor  15  and the drill tool  6  consists of a down hole-hammer or similar destruction tool. 
     In such case the compressed air coming from the compressor removes the material from the tool teeth or roller bit avoiding the obstruction of the drill tool  6 . The flow supplied by the compressor is low because the material must be moved and not lifted to the surface. 
     Whatever variant used, the method and the drill of the present invention can quickly drill wide diameter and high depth holes and can also working near bridges, buildings, electric power line or other obstacles, in lakes and sea. 
     A variant of the carrier canister of the drill has a structure that can be opened, for example, along the opening line  17  of FIG. 9 so allowing the easy discharging of the carried material into the surface.