CN218759726U - Rake tooth drilling tool and earth boring machine - Google Patents

Abstract

The present application provides a raker drilling tool and a trench excavator, including a connection portion for configuring to a trench excavator output shaft, the raker drilling tool further includes a bit portion having at least one bit rake, wherein at least one of the lengths of the bit rake protruding beyond a bottom end of the bit portion is the same or different. Through the utility model provides a rake teeth drilling tool has solved the drilling tool and can appear sticking to bore or creep into the difficulty in the gobi earth's surface, and drilling tool center point is easy to be pushed up the problem that dies can not the dowelling, has shortened the time spent of digging pit, has improved digging pit efficiency.

Description

Rake tooth drilling tool and earth boring machine

Technical Field

The application relates to the technical field of petroleum seismic exploration equipment, in particular to a rake tooth drilling tool and a pit digger.

Background

The surface characteristics of the quasi-songorian basin are rich and various, mainly comprising mountainous regions, gobi, farmlands, deserts, water areas, saline-alkali soil and the like, the temperature change of the basin is large, and the basin is accompanied with fixed accumulated snow in winter. For the frozen ground surface and the Gobi gravel ground surface on the rough-ploughed land in winter, the difficulty of digging a pit in an embedded pit of the geophone and the node instrument is extremely high. The traditional pit digging mode comprises manual pit digging and mechanical pit digging, wherein pick heads and iron lifts are usually adopted for manual pit digging, the pick heads are used for digging the surface layer loose, and then shovels are used for digging the loose surface layer, so that the labor intensity is high, and the pit digging efficiency is low; in mechanical digging, a low-power lithium electric power source can be adopted to drive the twist drill to drill holes, but the defects of insufficient power and difficulty in effective drilling exist; adopt the earth boring machine to drive the fluted drill drilling, although the power problem of avoiding the lithium electricity power supply has been avoided, nevertheless because the drilling tool that the tradition adopted of digging pit all is fluted cylinder structure, at great gravel gobi earth's surface, it is very difficult to cut large granule gravel, the drilling tool can appear blocking the brill or creep into the difficulty at this earth's surface, drilling tool center point is easy to be pushed up the dead on great gravel and can not get into the brill down, it is longer to lead to digging pit the time spent, consequently compare with artifical digging pit, the efficiency of machinery digging pit is not obviously promoted.

Disclosure of Invention

In view of the above problems, the first aspect of the invention provides a rake tooth drilling tool, which solves the problems that the drilling tool is difficult to block or drill on the gobi surface, the center point of the drilling tool is easy to jack up and down on larger gravel, and the digging efficiency is high when the digging is shortened.

The technical scheme of the invention is as follows:

a drag drilling tool comprising a connection for deployment to a earth boring machine output shaft, the drag drilling tool further comprising a bit portion having at least one bit drag, wherein at least one bit drag protrudes from a bottom end of the bit portion by the same or a different length.

Preferably, the bit part further comprises a bit rake body and a bit joint which are connected with each other, and at least one bit rake is arranged around the circumferential surface of the bit rake body at intervals.

As one preferable scheme, the rake drilling tool further comprises a drill rod, wherein a drill rod joint and the connecting part are respectively arranged at two ends of the drill rod, and the drill rod joint and the drill bit joint are matched with each other.

Preferably, the outer circumferential surface of the drill rod is sleeved with a helical blade.

Preferably, the end surface of the spiral blade becomes gradually larger in the direction from the drill rod joint to the connection part.

Preferably, the drill rod is a tapered drill rod, and the helical blade extends helically along the length of the tapered drill rod.

Preferably, a plurality of blade rake teeth are arranged on the lower end surface of the helical blade at intervals, and the blade rake teeth vertically extend out of the edge of the helical blade

Preferably, the blade edge of the helical blade close to one end of the drill rod joint is provided with an alloy head.

As one preferable scheme, the pitch of the spiral blade is 1.2cm-1.3cm.

The invention also provides a hole digger, wherein the output shaft of the hole digger is connected with the harrow teeth drilling tool.

Compared with the prior art, the method has the following advantages:

the invention provides a drag drilling tool, which comprises a connecting part used for being configured to an output shaft of a hole digging machine, and further comprises a drill bit part, wherein the drill bit part is provided with at least one drill bit drag, and the length of the at least one drill bit drag protruding out of the bottom end of the drill bit part is the same or different.

By adopting the technical scheme, the drill bit rake teeth arranged on the drill bit part can replace the drill bit of the original drilling tool to be firstly contacted with the earth surface, the drill bit rake teeth can be in eccentric contact with gravel when being contacted with the gravel, and the plurality of drill bit rake teeth cannot be simultaneously contacted with the same gravel surface due to uneven gravel surface, so that the drill bit rake teeth and the gravel form eccentric contact, the gravel can be stirred by the drill bit rake teeth in the rotating process instead of being propped against the gravel, the gravel is extruded beside the drill bit, and the gravel and sandy soil with large particles can be drilled out of the ground, so that the problem that the center point of the drilling tool is propped against the larger gravel and cannot be drilled down in the drilling process of the drilling tool is solved, and the pit digging efficiency is greatly improved;

compared with the traditional machine for cutting the large gravel, the drill bit rake tooth provided by the embodiment of the invention can stir the large gravel to shift, and drill the shifted gravel out of the ground surface, so that the power required for stirring the gravel is far less than that required for cutting the gravel, and the time for digging a pit is greatly shortened;

according to the drill bit rake teeth provided by the embodiment of the invention, the plurality of drill bit rake teeth are different in length, and are in contact with the uneven ground surface in the drilling process, so that the time for the drill bit part to stir gravel is shortened in the drilling process.

Therefore, the rake tooth drilling tool provided by the embodiment of the invention is not only suitable for digging pits of embedded pits of node instruments on the terrains such as mountainous regions, gobi, farmlands, deserts, water areas, saline-alkali lands and the like, but also particularly suitable for digging pits of embedded pits of node instruments on complex earth surfaces such as frozen earth surfaces, gobi gravel earth surfaces and the like in rough ploughing fields in winter, has the advantages of safety, reliability, time and labor conservation, wide application scenes and the like, and has good scale popularization and application prospects.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings needed to be used in the description of the present application will be briefly introduced below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

Fig. 1 is a schematic view of the overall structure of a drag bit drilling tool according to an embodiment of the present invention.

Description of reference numerals:

11. a connecting portion; 12. a drill bit rake tooth; 13. a drill bit rake tooth body; 14. a drill pipe joint; 15. a bit sub; 16. a drill stem; 17. a helical blade; 18. blade rabble blade.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

With the development of seismic exploration technology, geophones are widely used in large areas. In the process of oil exploration, a controllable seismic source or a well gun generates seismic waves, seismic wave feedback signals are received through a detector and transmitted to an instrument to obtain seismic data, and the underground geological structure and the oil reservoir condition are researched after analysis and processing. The digging efficiency and quality of the embedded pits of the detectors and the node instruments are one of the important factors influencing the high-efficiency seismic exploration and collection. As the field for collecting seismic data is mostly in various field environments such as desert abdominal land, gobi desert, hills, mountainous regions and the like, the digging difficulty of the buried pit of the detector is different. Particularly, in complex earth surfaces such as the quasi-songorian basin and the like, frozen earth surfaces and gobi gravel earth surfaces of rough-ploughed lands in winter are common, the digging difficulty is extremely high, and the traditional digging tool is not suitable for the terrain.

Traditional for digging pit instrument mainly is the combination of gas diesel earth boring machine and fried dough twist drill and tractor earth boring machine and the combination of fried dough twist drill, because the drilling tool is fried dough twist cylinder structure, it exists following several at least not enoughly:

1. on the gobi surface with large gravels, large gravels are very difficult to cut, a drilling tool is difficult to block or drill on the surface, and the center point of the drilling tool is easy to jack on the large gravels and cannot drill down;

2. the Xinjiang climate is dry, the ground surface has low water content and contains much gravel and sandy soil, according to the research and analysis of the vertical helical blade 17 material conveying principle, along with the drilling of the helical blade 17, the pit wall naturally collapses, the diameter of the upper pit wall is larger and larger, a funnel-shaped conical hole pit is formed, the gap between the funnel-shaped conical hole pit and the helical blade 17 is larger and larger, the material cannot generate enough friction with the pit wall to weaken upward thrust, and even rolls to the edge of the blade under the action of centrifugal force, namely leaks, so that the efficiency of conveying the material to the ground surface is reduced, and even the material cannot drill downward;

3. traditional mechanized excavation drilling tool just needs the biggest moment of torsion to cut the earth's surface when contacting ground because of the fried dough twist cylinder structure, and power requirement is high, the cutting force demand is big, and it is bigger, efficiency is lower to freeze thick arable land and creep into the degree of difficulty especially on great gravel gobi and bold, and because of the reaction force is big in the drilling process, causes the drilling tool swing big, and poor stability has certain potential safety hazard.

Therefore, the traditional tool for digging pits has the problems of high drilling difficulty, low digging efficiency, large swing of a drilling tool, poor stability and the like, is directly applied to digging pits in embedded pits with complex terrain, has no obvious advantages compared with manual digging pits, needs to coordinate various mechanical parts, wastes time and labor, and has high manual labor intensity and low efficiency due to the adoption of manual digging.

In view of the above problems, embodiments of the present invention provide a raker drill that can increase stability and safety of a drilling process while improving drilling ability and efficiency of the apparatus when using a mechanized excavation apparatus for a complicated surface such as a frozen surface and a gobi gravel surface in rough-ploughed land in winter.

Referring to fig. 1, fig. 1 is a schematic view illustrating an overall structure of a drag drill according to the present invention.

The main purpose of the present invention is to solve the problem that it is difficult to cut large gravel in the gobi surface with large gravel, the drilling tool is difficult to drill or jam on the surface, the center point of the drilling tool is easy to be dead on the large gravel, and the drilling tool can not be drilled, as shown in fig. 1, the embodiment of the present invention provides a rake drilling tool, which comprises a connecting part 11 used for being configured to an output shaft of a digging machine, and the rake drilling tool also comprises a drilling head part, wherein the drilling head part is provided with at least one drill head rake tooth 12, and the length of the at least one drill head rake tooth 12 protruding out of the bottom end of the drilling head part is the same or different.

Specifically, the earth boring machine can be a gasoline engine earth boring machine, a diesel engine earth boring machine, a tractor earth boring machine and other commercially available earth boring equipment, an output shaft of the earth boring machine is connected to the connecting part 11 of the rake tooth drilling tool, and the output power of the earth boring machine can be transmitted to the rake tooth drilling tool, so that the rake tooth drilling tool rotates in a preset torque and direction. Taking the drill bit part of the drilling tool as the bottom direction as an example, the connecting part 11 is positioned at the top end of the rake tooth drilling tool and connected with the earth boring machine, the drill bit part vertically faces the ground, and when the earth boring machine drives the rake tooth drilling tool to move up and down, the earth boring machine drives the rake tooth drilling tool to drill up and down. The structure of the connecting part 11 is selected according to the structure of a power head output shaft of the earth boring machine, for example, when the power head output shaft of the earth boring machine is in a disc structure, the connecting part 11 is a connecting disc; when the power head output shaft of the earth boring machine is of a spline structure, the connecting part 11 is a spline shaft and a fixed pin, and the connecting part 11 and the earth boring machine output shaft are mutually clamped. The mounting structure of the connecting part 11 and the earth boring machine belongs to a common structure of earth boring equipment, and the embodiment is not described in detail.

Specifically, the bit rake 12 is a high hardness alloy head, or a percussion bit is cut off with the bit edge portion as the bit rake 12. The bit portion can be the original drill bit one end of twist drill, gets rid of the central point of twist drill, and drill bit rake teeth 12 set up around the bit portion to replace the single-point design of original drill bit, a plurality of drill bit rake teeth 12 stretch out the bottom of bit portion, as the position with the earth's surface first contact, play the effect of creeping into. In this embodiment, the plurality of tines 12 may be aligned with the drill bit or extend downwardly at an angle to the drill bit, and may be selected based on the distribution of the gravel in the earth's surface. Since the power required to cut gravel is much greater than the power required to move gravel, or at the same power output of the power source, moving gravel is easier to achieve than cutting gravel. According to the invention, large-particle gravels are stirred through the plurality of drill bit rake teeth 12 to be displaced, and then the gravels are integrally conveyed to the ground surface through the drilling tool, so that the time for stirring the gravels is shortened, and the pit drilling efficiency is greatly improved.

Due to the fact that the surface formed by the gravels in the gobi gravel ground surface is uneven, the lengths of the drill bit rake teeth 12 are different, a plurality of contact points can be formed between the drill bit rake teeth and the gravels in the drilling process, and the time for stirring the gravels is shortened.

In a further preferred embodiment, the bit part further comprises a rake body 13 and a bit adapter 15 connected to each other, and at least one of the rake teeth 12 is arranged at intervals around the circumference of the rake body 13.

More preferably, the rake drilling tool further comprises a drill rod 16, wherein a drill rod joint 14 and the connecting part 11 are respectively arranged at two ends of the drill rod 16, and the drill rod joint 14 and the drill bit joint 15 are matched with each other.

Specifically, bit sub 15 may be a female or male sub, and drill pipe sub 14 may be a male or female sub that mates with bit sub 15. Specifically, bit sub 15 is a female bit sub and tool sub 14 is a male button. The drill rod joint 14 is welded at the lower end of a drill rod 16 and clamped with the drill rod joint 14, so that the power of a drilling tool is transmitted to the drill head to overcome the resistance of the stratum to the drill head. The button type design of wherein connecting is the left-hand thread, prevents that the drilling tool is at the drilling in-process, and the pine of drill bit pin takes off. The cooperation of the female and male connectors provides a releasable connection between the drill bit portion and the drill rod 16, facilitating replacement of the drill bit portion when the drill bit portion is damaged. Of course, the drill rod 16 and the drill bit portion may be integrally formed without the need for the bit sub 15 and the drill bit sub 14.

Specifically, the drill rake teeth body 13 is a cylinder having the same shape as the drill stem 16 and is made of an iron material, and two or three drill rake teeth 12 are welded on the circumferential surface of the drill rake teeth body 13 and form a certain angle, for example, two drill rake teeth 12 are axially symmetrically distributed at two ends relative to the center of the drill rake teeth body 13, and three drill rake teeth 12 are centrally symmetrically distributed relative to the center of the drill rake teeth body 13 and are spaced by 120 ° from each other.

The method aims at solving the problems that the conventional cylindrical spiral drill bit is adopted in the conventional mechanical drilling tool, and the dug hole wall naturally collapses in the rotary digging process to form a funnel-shaped conical hole, so that the drill bit drills out materials for repeated transportation, and the hole drilling efficiency is influenced; and the cylindrical spirochaeta structure is creeping into the process, and the drill bit cross-section is big when contacting ground, just needs the biggest moment of torsion to cut the earth's surface, and it is big, the inefficiency to freeze the rough tillage ground drilling degree of difficulty on great gravel gobi and bold, and because of earth's surface reaction force is big, the drilling tool swing is big, and stability is relatively poor, has the problem of certain potential safety hazard, this application has proposed a new technical scheme:

a drag drilling tool comprising a connection 11 for deployment to a earth boring machine output shaft, the drag drilling tool further comprising a bit portion having at least one bit drag 12, wherein the at least one bit drag 12 protrudes the bottom end of the bit portion by the same or different length. A drill rod 16 is arranged between the drill head part and the connecting part 11, and the peripheral surface of the drill rod 16 is sleeved with a helical blade 17.

Wherein the end surface of the helical blade 17 becomes gradually larger in the direction from the drill rod coupling 14 to the connection part 11.

Specifically, the drill rod 16 is made of a steel pipe with the diameter of 90mm, the helical blade 17 is made of a steel plate with the thickness of 8mm, the center inner hole of the pulled helical blade 17 is uniformly welded in a helical shape along the surface of the drill rod 16 in a full-welding mode, and the helical blade 17 is uniformly dispersed on the drill rod 16 between the drill rod joint 14 and the connecting part 11. Through helical blade 17's transport principle, helical blade 17 drills in-process, and the material that is stirred by drill bit rake teeth 12 is carried to the earth's surface through helical blade 17 under the centrifugal force effect, promotes the efficiency that the material was carried to the earth's surface.

The end face of the spiral blade 17 is in a cone shape gradually enlarged from the bottom to the top to form a structure that the inner side of the spiral blade 17 is cylindrical and the outer side of the spiral blade 17 is conical, wherein the vertex angle of the cone spiral blade 17 is slightly larger than that of a funnel-shaped cone hole pit formed by natural collapse, in the pit drilling process, the cone spiral blade 17 is effectively contacted with a pit wall, and the efficient vertical spiral blade 17 material conveying principle is fully utilized to enable gravel and sandy soil to generate enough friction force with the pit wall under the action of centrifugal force, so that the gravel and sandy soil are prevented from rotating along with the spiral structure, the gravity of the gravel and sandy soil falling is overcome, and better upward thrust is formed, so that the gravel and sandy soil are vertically conveyed to the ground surface, and the efficiency of conveying the gravel, sandy soil and other materials to the ground surface is improved.

In yet another implementable aspect, the drill pipe 16 is a tapered drill pipe 16, and the helical blade 17 extends helically along the length of the tapered drill pipe 16. In this embodiment, the helical blades 17 welded on the circumferential surface of the drill rod 16 extend uniformly, the end faces of adjacent helical blades 17 have the same shape and size, and since the drill rod 16 is conical, the outer side of the helical blades 17 also forms a conical structure, in the process of drilling a pit, the conical helical blades 17 are effectively contacted with the pit wall, and the efficient material conveying principle of the vertical helical blades 17 is fully utilized, so that sufficient friction force is generated between gravel and sandy soil and the pit wall under the action of centrifugal force, the gravel and sandy soil are prevented from rotating along with the helical structure, the gravity of the gravel and sandy soil falling is overcome, and good upward thrust is formed, so that the gravel and sandy soil are conveyed to the ground surface vertically, and the efficiency of conveying materials such as the gravel and the sandy soil to the ground surface is improved.

Further, the blade edge of the helical blade 17 near one end of the drill rod joint 14 is provided with an alloy head. The small end of the conical helical blade 17 is firstly contacted with the ground, and an alloy head is added on the knife edge of the small end of the conical helical blade 17, so that the wear resistance of the helical blade 17 can be increased, and the service life of the drilling tool is prolonged.

Furthermore, the pitch of the conical helical blade 17 is controlled between 1.2cm and 1.3cm, so that the gravel and soil material cut at the bottom of the well can be quickly returned to the surface.

In another preferred embodiment extended from the present embodiment, a plurality of blade tines 18 are spaced apart from the lower end surface of the helical blade 17, and the plurality of blade tines 18 vertically extend out of the edge of the helical blade 17. In this embodiment, the below welding of blade rake teeth 18 and helical blade 17's terminal surface is as an organic whole, and the usable blade rake teeth 18 dial loose wall of a well large granule gravel, need not cut large granule gravel, and the gravel accessible cone helical blade 17 of dialling the pine is carried to the earth's surface perpendicularly, improves the efficiency that materials such as gravel and sand carried to the earth's surface.

As a specific explanation of the present embodiment, the blade tines 18 may be of the same construction as the bit tines 12. And a plurality of blade tines 18 are evenly spaced on the curved plane of the helical blade 17, for example each blade tine 18 is spaced 120 ° apart and projects perpendicularly 10mm from the edge of the helical blade 17. During the drilling process, the drill bit rake teeth 12 firstly stir large gravel particles, and during the process that the large gravel particles and sandy soil are conveyed to the ground surface through the spiral blades 17, the blade rake teeth 18 can also stir the large gravel particles protruding from the pit wall, so that the large gravel particles are quickly separated from the pit wall, and the drilling efficiency is improved.

Thus, as shown in fig. 1, the rake drilling tool provided by the present invention sequentially comprises a connecting portion 11, a drill stem 16, a drill stem joint 14, a drill bit joint 15 and a drill bit rake body 13 from top to bottom, wherein 3 drill bit rake teeth 12 are welded on the drill bit rake body 13, the connecting portion 11 is a connecting disc with an eight-hole diameter of 140mm and a thickness of 20mm, the end surface of a helical blade 17 is sequentially reduced from top to bottom, the helical blade 17 is welded on the surface of a cylindrical drill stem 16 to form a conical helical blade 17 with a cylindrical inner side and a conical outer side, and the blade rake teeth 18 are dispersedly arranged on the end surface of the conical helical blade 17 at an interval of 120 ° close to the edge. The cone outer surface and the rake teeth which are matched with the wall of the naturally collapsed pit are designed, so that the material conveying capacity and efficiency are improved, the shifting time of large-particle gravels is shortened, meanwhile, the section of the cone drilling tool is gradually increased from the bottom to the top, the cutting reaction force when the drilling tool is in contact with the ground is reduced, reaming cutting is realized, the cutting drilling capacity and efficiency are improved, and the stability and the safety of the drilling process are improved. Compared with the traditional twist drilling tool, the efficiency of digging the frozen ground surface on rough ploughing ground in winter is improved by more than 5 times, and the efficiency of digging the pit on the Gobi gravel ground surface is improved by more than 3 times. Compared with the traditional manual digging, the efficiency of the frozen earth surface digging on rough-ploughed land in winter reaches the digging efficiency of 10-20 people, the efficiency of the digging on Gobi gravel earth surface reaches the digging efficiency of 5-10 people, and the larger the difficulty of the manual digging is, the larger the efficiency promotion amplitude is.

Another aspect of the invention is to provide a trench excavator having an output shaft to which the tine drilling tool system is connected. As for the above-described embodiment of the earth boring machine, since it is substantially similar to the drag tool embodiment, the description is relatively simple and reference may be made to the partial description of the drag tool embodiment.

It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

It should also be noted that, in this document, the terms "upper", "lower", "left", "right", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Moreover, relational terms such as "first" and "second" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions or neither should the relative importance be understood or implied. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal.

The present application provides a drag bit drilling tool and a trench excavator, which are described in detail above, and the principles and embodiments of the present application are explained herein using specific examples, and the above description of the embodiments is only for the purpose of understanding the present application, and the content of the present description should not be construed as limiting the present application. While various modifications of the described embodiments and applications will be apparent to those skilled in the art in light of the disclosure herein, it is not desired to be exhaustive or exhaustive all of the embodiments and obvious variations or modifications are possible in light of the above teachings.

Claims (10)

1. A drag drilling tool comprising a connection for deployment to a earth boring machine output shaft, the drag drilling tool further comprising a bit portion having at least one bit drag, wherein at least one of the bit drag protrudes a bottom end of the bit portion by the same or a different length.

2. The rake drilling tool of claim 1, wherein the bit portion further comprises interconnected bit rake bodies and bit subs, at least one of the bit rake bodies being spaced around a circumference of the bit rake bodies.

3. The rabble drilling tool as claimed in claim 2, further comprising drill pipe having a drill pipe joint and the connecting portion at opposite ends thereof, the drill pipe joint and the drill bit joint being complementary to each other.

4. The drag drilling tool as claimed in claim 3, wherein the drill pipe is provided with helical blades around its outer circumference.

5. The drag bit tool of claim 4, wherein said helical blades are progressively larger in end surface area in the direction from said tool joint to said connection section.

6. The rake drilling tool according to claim 4, wherein the drill pipe is a tapered drill pipe, and the helical blade extends helically along the length of the tapered drill pipe.

7. The drag drilling tool according to claim 4, wherein a plurality of blade teeth are spaced from the lower end surface of the helical blade, and extend perpendicularly from the edge of the helical blade.

8. The drag bit tool of claim 4, wherein the cutting edge of the helical blade adjacent the end of the tool joint is provided with an alloy head.

9. The drag bit drilling tool of claim 4, wherein the pitch of said helical blades is between 1.2cm and 1.3cm.

10. A trench cutter, characterized in that the output shaft of the trench cutter is connected with a drag bit drilling tool according to any one of claims 1-9.

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