EP2927417B1 - Self-opening rotating percussion drill tip, especially for overburden drilling - Google Patents

Description

Field of the invention

The invention relates to an opening rotary percussion drill bit, in particular for overlay drilling and a drilling device with a drill bit according to the preambles of the independent claims.

State of the art

Overhead drill bits are used to create a wellbore with a diameter greater than the outside diameter of the tubing to be inserted. Frequently used for cased piercing of overlay floors without disturbing hard soil deposits are opening drill bits are used, which can pierce these earth layers rotary drilling. The movable part of the drill bit is driven to the bottom of the hole by rotation in the working direction of rotation in order to obtain a bore diameter that is greater than the outer diameter of the casing. The cutting edges of these drill bits are usually soldered Carbide plates or fitted with exchangeable round shank bits. When changing the drill string and after completion of the drilling of the moving part of the drill bit can either retracted by rotation against the working direction or folds back by simply pulling back into the casing and can be withdrawn.

However, such opening drill bits are not suitable for drilling through rocky fault zones.

In overlay floors, the use of a double piping may be necessary, wherein the inner rod is equipped with a drill bit for rotary impact drilling to drill through rocky soil deposits, in which rotary drilling approaches to limits. This Schlagbohrantriebe come in the form of hydraulic hammers, which are mounted behind a rotary drive together on a slide and sitting on the carriage of a drill, used. One speaks then of top hammers, which are coupled to the inner rod and are drilled rotary-drilled, wherein the outer rods are fitted at the lower end with a ring bit and coupled to the rotary drill drive, only rotary drilling, are usually drilled in opposite directions. In this method, the impact energy is transferred to the drill bit via the inner rod. Alternatively, it is also possible that the inner rod is also driven by a rotary drive and the impact energy to the drill bit by means of an Imlochhammers (also countersunk hammer, DTH hammer or "down the hole hammer" called), which are operated with air or water is transmitted. These DTH hammers then sit at the bottom of the hole between the rotary hammer bit and the inner rod, whereby the energy is supplied through the inner rod. However, if the rocky soil deposits are very powerful, they can cause durability problems the ring bit on the outer linkage be connected.

Known from the Odex - boring systems for countersunk hammers are also eccentric drill bits, which have an eccentric equipped with carbide pins ring, a so-called scraper, which can be rotated around the drill bit body.

The eccentric portion of these types of impact augers is extended deepest by rotation in the direction of operation when in contact with the wellbore to obtain a bore diameter greater than the outer diameter of the tubing.

These eccentric bits are loaded on one side by design and have a cutting edge with a few hard metal pins. Also, relatively high deviations from the drilling axis can occur. Furthermore, the propulsion power is low and the retraction of the eccentric against the working direction problematic because unintentionally threaded connections can solve.

From the EP 563 561 A1 is a drill bit for overlay drilling known. The drill bit has a drill head on a drill bit carrier. The drill bit carrier is rotatably connected to a driven inner tube linkage. On the drill head a plurality of symmetrically arranged about its circumference arranged pivot elements which are arranged in the pivoted state in recesses between fixed end faces in the drill head so that they come to rest within the drill head diameter and in the swung-out state by a predetermined amount beyond the Bohrkronendurchmesser. In this case, each pivoting element is mounted with an eccentrically arranged Bohrkronenträger in the drill head. In this percussion drill bit are arranged concentrically arranged folding blades along the Bohrkronenachse rotating. Upon contact at the bottom of the well, the blades are extended by rotation in the direction of travel to obtain a bore diameter greater than the outer diameter of the tubing. If retraction of the folding blades is necessary, for example in a boom extension or after completion of the bore, this requires a rotation counter to the working direction, the folding blades can be retracted and withdrawn through the outer casing. As with the eccentric bits, this retraction is problematic because the drill pipes are threaded, and rotation counter to the working direction is partially associated with loss of drill string, etc., if any threaded joints are loosened.

From the WO 01/81708 A1 a drill bit is known in which the drill head is formed of two folding wings, which can be pressed apart or collapsed by means of an actuator in order to increase the Bohrradius or to move the drill bit through the casing. This drill bit is due to its construction with many moving parts for controlling the folding blades suitable only for rotary drilling. The actuator would be driven by the introduction of impact energy from the Verrieglungsposition, whereby the folding wings would fold again.

The following prior art shows opening rotary drill bits that are not suitable for rotary impact drilling.

From the WO 01/81708 A1 a drill bit is known in which the drill head is formed of two folding wings, which pressed apart or collapsed by means of an actuator can be used to increase the Bohrradius or to move the drill bit through the casing.

So is out of the DE 10 2010 015 474 A1 a drill head with a base body in which it has a shaft for connection to a drill pipe and a pilot drill and main drill, wherein the main drill are arranged partially pivotally arranged on the main body cutting strips. At least one cutting edge of the pivotable main drill protrudes in the swung-out state beyond the inner diameter of a guide tube surrounding the drill string and is arranged in the swung-in state within the inner diameter of the guide tube. In this case, all main drills are movably arranged on the base body. The folding axis of the main drill is arranged transversely to the longitudinal center line of the base body.

From the DE 295 13 325 U1 is a drill bit with a shank having a base body and at least one hingedly mounted on the base body, at least one cutting body having folding blade, the body via the shaft to a guided in a guide tube drill pipe is rotatably connected and wherein each folding edge up to a stop can be folded and is in the folded position within the inner diameter of the guide tube. Each folding blade is supported in the deployed position on a contact surface of the drill bit and is at least a portion of its cutting body outside the outer diameter of the guide tube. It is provided that the base body has a base plate and at least one non-hinged cutting body, the base plate for each folding edge the stop, the contact surface and a guide, each folding blade about a lying in a direction substantially perpendicular to the drill bit axis plane folding axis substantially radially is arranged foldable and that the distance between each hinged cutting body in the folded position to the drill bit axis is greater than the distance of the folding axis to the drill bit axis.

When pulling out the drill bit from the well, regardless of the direction of rotation of the drill bit by the contact with the end face of the guide tubes forcibly retracted.

From the AT 354 960 B is known a drill bit with two folding wings, which are structurally designed so that when the rotary drill head, the folding wings are driven from a first position to a second position.

task

The object of the invention is to provide a drill bit in which a particularly effective power transmission to the drill bit is done, the movement of the drill bit within a rough is favorable, the change of the Bohrradius simplified and the prior art is improved.

Another object is to provide a corresponding drilling device with a drill bit.

solution

The objects are achieved by the inventions having the features of the independent claims. Advantageous developments of the inventions are characterized in the subclaims, the description and the drawings. The wording of all claims is hereby incorporated by reference into the content of this specification. The inventions also include all reasonable and in particular all mentioned combinations of independent and / or dependent claims. In the following, individual process steps are described in more detail. The steps do not necessarily have to be performed in the given order, and the one to be described Method may also include other, not mentioned steps.

The invention relates to a drill bit, in particular for overburden drilling, comprising a drill head and a drill bit carrier carrying the drill bit, with at least two folding wings, each of which is reciprocally movable between a first position and a second position, wherein each of the folding wings in the first position within a drill pipe and in the second position projects beyond the Bohrrohrdurchmesser, and wherein the folding wing at its free end has an end face, preferably with a number of cutting elements.

The drill bit is designed in particular as a rotary impact drill bit, which opens after passing through an outer casing and drills larger than the outer diameter of the outer casing measures and finally folds back by simply pulling back. The drill bit has sufficient carbide or similar cutting elements to achieve proper drilling performance.

It is proposed that each of the folding wings is arranged transversely to a Bohrkronenträgerlängsachse pivotally mounted on Bohrkronenträger and is designed so that when rotating drill bit an operative connection with a drilling object generates a torque on the folding wing transverse to Bohrkronenträgerlängsachse and the folding wing from the first to the second Position drives. The drill bit carrier is designed as a shaft. The drill bit has the largest possible contact surface between the shaft and folding wing for impact energy transmission.

The change in the Bohrradius via a passive movement of each of the folding wings due to the structural design of the folding wing, without additional mechanics or actuators from the drill bit or the drilling device. Once the drill bit of the rotary drill bit with the drilling object, such as rock and the like, i. with the contact surface to be machined, in contact and / or as long as the drill head of the rotating drill bit with the drilling object remains in contact, a torque acts on the folding wing, which automatically moves the folding wing, based on the Bohrkronenträgerlängsachse, outwardly. If the drill bit is stationary, no torque acts on the folding wing, and the folding wing can be moved back into the outer casing without any particular resistance and without twisting the drill bit in the opposite direction of rotation. The torque can in particular be caused by an interaction between the folding wing and the drilling object, in particular via frictional forces on the drilling object. If the drill bit is stationary, no torque acts on the folding wing, and the folding wing can be moved back into the outer casing without any particular resistance and without twisting the drill bit in the opposite direction of rotation.

In a boom extension or after completion of the bore, the percussion drill bit can be withdrawn without rotation against the working direction through the casing, since the folding cutting elements assume a smaller diameter than the inner diameter of the outer casing.

The folding wing can, for example, with bolts transversely to Bohrkronenträgerlängsachse, be rotatably or pivotally mounted in Bohrkronenträger. It is preferable if, in the first position, the radial distance of the highest point of the folding wing from the pivot axis has a positive value, since then a secure unfolding of the folding wing is ensured.

Each of the folding wings is formed in the manner of a circle segment, for example as a semicircular segment. A rounded outer contour is favorable for a movement in a piping. Similarly, a rounded outer contour for initiating a movement of the flap is transverse to Bohrkronenträgerlängsachse for changing the Bohrradius advantageous.

The end face is inclined in the first position against the Bohrkronenträgerlängsachse by a first angle, wherein the end face drops from outside to inside. As a result, a bevelled edge is formed on an outer region of the folding wing. On this beveled edge cutting elements are arranged, for example in the form of carbide pins. It is favorable if the angle by which the end face can be inclined has a value between 17 ° and 10 °, preferably 15 °. The angle of the folding leaf in the folded state can vary between 10 ° and 15 °, as this depends on the wall thickness of the casing. For the values common manufacturing tolerances apply in the production of the folding wing. It is advantageous if the end face, if the folding wing is maximally deflected, oriented perpendicular to Bohrkronenträgerlängsachse. On the end face advantageously cutting elements, for example in the form of carbide pins, can be arranged. According to a favorable Embodiment, the folding wing a region on its opposite side of the end face which, in the second position, is inclined at a second angle to the drill bit carrier longitudinal axis, the region falling from outside to inside. Advantageously, this area serves as a sliding surface when the drill head is to be withdrawn into a casing. The tilt assists in sliding the flap back from the second position to its first position within the diameter of the collar. Advantageously, the angle can have a value between 20 ° and 10 °, preferably between 18 ° and 12 °, particularly preferably 15 °. For the values common manufacturing tolerances apply in the production of the folding wing.

The folding wings have in the unfolded state to the free end of the drill bit a curvature inwards, which is for the directional accuracy during drilling beneficial.

According to a favorable embodiment, a bevelled edge can be provided on the folding wing radially outward on the end face, which forms an outer bore diameter in the second position. Conveniently, the beveled edge may be equipped with cutting elements, such as cemented carbide pins. This makes it possible to work even at the outermost diameter drill with a large number of cutting elements, resulting in a good drilling performance. The folding wing is in its second position, the beveled edge is at a favorable angle to Bohrkronenträgerlängsachse and preferably forms the outermost bore diameter of the drill collar.

According to the invention, two folding wings are provided opposite each other with respect to the drill bit carrier longitudinal axis. These can be identical. The folding wing is indoors arranged eccentrically a nose adjacent to a recess, so that the lugs of the two opposing folding wings can engage in the first position in the opposite recess. This allows a compact arrangement of the folding wings in the first position and a large work surface in the second position. Two folding wings result in a very stable construction.

It is also conceivable to provide more than two folding wings. This can be favorable for larger diameter drill bits.

According to a favorable embodiment, at least one rinsing liquid supply can be provided within the drill bit carrier. The pressure of the flushing liquid may assist the movement of the hinged wing or wings from the first to the second position. Furthermore, the rinsing fluid can keep the mechanics of the drill bit clean and flush away cuttings. For this purpose, advantageously, a drilling dust outlet can be provided on the drill bit carrier, e.g. in the form of one or more flats on the outer circumference.

According to a further aspect of the invention, a drilling device with a drill bit as described above is proposed, which is guided or feasible in a Bohrkronenträger. The Bohrkronenträger can be rotatably coupled to an output shaft or coupled. Advantageously, the drill bit can be driven in rotation and / or hammering.

The drill bit can open to full bore diameter when guided by a drill string through tubing that is in the ground to support a drill wall. This can advantageously be continued drilling ahead of the piping.

Furthermore, the invention according to another aspect comprises an opening rotary percussion drill, which inevitably opens after passing through an outer casing at basic contact and drills larger than the diameter of the outer casing measures whose movable parts are rotatably mounted transversely to the crown shaft and form a drill head and the Drilling energy is supplied by hydraulic hammers or Imlochhämmer supplied and can be easily withdrawn into the outer tube for linkage change or after completion of work without twisting against the working direction of rotation.

Further details and features will become apparent from the following description of preferred embodiments in conjunction with the subclaims. In this case, the respective features can be implemented on their own or in combination with one another. The possibilities to solve the problem are not limited to the embodiments. For example, area information always includes all - not mentioned - intermediate values and all imaginable subintervals.

Further advantages emerge from the following description of the drawing. The embodiments of the invention are shown schematically in the figures. The same reference numerals in the individual figures designate the same or functionally identical or with respect to their functions corresponding elements. The figures are merely examples and are not intended to be limiting. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

• Fig. 1 eine teilweise aufgeschnittene Darstellung einer Bohrvorrichtung mit einer Bohrkrone in einer ersten Position nach einem Ausführungsbeispiel der Erfindung;
• Fig. 2 eine teilweise aufgeschnittene Darstellung der Bohrvorrichtung aus Figur 1 mit der Bohrkrone in einer zweiten Position;
• Fig. 3 eine teilweise aufgeschnittene Explosionsdarstellung der Bohrvorrichtung aus Figur 1;
• Fig. 4 eine Seitenansicht eines Klappflügels nach einem Ausführungsbeispiel der Erfindung;
• Fig. 5 in Draufsicht den Klappflügel aus Figur 4;
• Fig. 6 eine seitliche Schnittansicht durch eine Bohrkrone mit zwei Klappflügeln in einer ersten Position;
• Fig. 7 in Draufsicht die Bohrkrone aus Figur 6;
• Fig. 8 eine seitliche Schnittansicht durch die Bohrkrone aus Figur 6 mit zwei Klappflügeln in einer zweiten Position;
• Fig. 9 in Draufsicht die Bohrkrone aus Figur 8;
• Fig. 10 eine teilweise geschnittene Darstellung eines Klappflügels in einem Bohrkronenträger in einem zweiten ausgeklappten Zustand;
• Fig. 11 eine teilweise geschnittene Darstellung eines Klappflügels in einem Bohrkronenträger in einer ersten, eingeklappten Position.

In detail, for example:

• Fig. 1 a partially cutaway view of a drilling device with a drill bit in a first position according to an embodiment of the invention;
• Fig. 2 a partially cutaway view of the drilling device FIG. 1 with the drill bit in a second position;
• Fig. 3 a partially cutaway exploded view of the drilling device FIG. 1 ;
• Fig. 4 a side view of a folding wing according to an embodiment of the invention;
• Fig. 5 in plan view the folding wing FIG. 4 ;
• Fig. 6 a side sectional view through a drill bit with two folding wings in a first position;
• Fig. 7 in top view, the drill bit FIG. 6 ;
• Fig. 8 a side sectional view through the drill bit FIG. 6 with two folding wings in a second position;
• Fig. 9 in top view, the drill bit FIG. 8 ;
• Fig. 10 a partially sectioned view of a folding wing in a Bohrkronenträger in a second unfolded state;
• Fig. 11 a partially sectioned view of a folding wing in a Bohrkronenträger in a first, folded position.

Numerous modifications and developments of the described embodiments can be realized. Identical or similar elements are numbered in the figures with the same reference numerals.

The FIGS. 1 to 3 show in a partially cutaway view a drilling device 100 with a drill bit 10 according to an embodiment of the invention in a first position ( FIG. 1 ), a second position ( FIG. 2 ) and in exploded view ( FIG. 3 ). The drilling device 100 further includes a drive train, not shown.

The drill bit 10 for overburden drilling is guided in a tube 60, which is shown partially cut open. The drill bit 10 comprises a drill head 30 and a drill bit carrier 20 carrying the drill head 30 with a drill bit carrier longitudinal axis 70. The drill bit carrier 20 has a coupling piece 80 at its end opposite the drill bit 30, with which the drill bit carrier 20 is connected to a drive for rotating and / or beating Driving the drill head 30 can be coupled (not shown). In the interior of the Bohrkronenträgers 20 a rinsing liquid line, not shown, is arranged. On the outer circumference of the Bohrkronenträgers 20 a flattening can be seen, which forms a Bohrmehlablauf 90. Advantageously, another such flattening is provided diametrically opposite as Bohrmehlablauf 90.

In this embodiment, the drill head 30 comprises two folding wings 32, 34, which are arranged transversely to the Bohrkronenträgerlängsachse 70 pivotally mounted on the Bohrkronenträger 20 and, relative to the Bohrkronenträgerlängsachse 70, opposite. In this case, each folding wing 32, 34 with a bolt 12, 14 which is inserted into a corresponding bore 22, 24 of the Bohrkronenträgers 20, pivotally mounted, namely transversely, in particular perpendicular to Bohrkronenträgerlängsachse 70th

Each folding wing 32, 34 is formed on its folding wing head 35 of a segment of a circle and has an end face 40 which is bent at its outer edge. The radially outwardly disposed on the end face 40 beveled edge 38 forms in the second position has an outer bore diameter of the drill bit 10. The end face 40 points in the working direction (to the right in FIGS. 1-3).

On the end face 40 and the beveled edge 38 cutting elements 50 are used, for example in the form of hard metal pins, which are embedded in corresponding holes in the respective surfaces. The cutting elements 50 on the end face 40 and on the bevelled edge 38 may be configured differently.

In the first position ( FIG. 1 ), the two folding wings 32, 34 are folded inwards and within the diameter of the tube 60 and thus of the drill bit diameter d10 (FIG. FIG. 6, FIG. 7 ) arranged. The folding wings 32, 34 are designed so that they can partially interlock. For this purpose, a recess 44 is provided in the interior region of each folding wing 32, 34, which can receive a nose 42 of the respectively opposite folding wing 34, 32.

In the second position ( FIG. 2 ), the folding wings 32, 34 are folded outwards and protrude beyond the diameter of the tube 60 or the drill bit diameter d10 (FIG. FIG. 8, FIG. 9 ).

The end face 40 is inclined sloping inwardly against the drill bit carrier longitudinal axis 70 by a small angle. Due to their structural design, in particular their bevels, the folding wings 32, 34 passive, ie without separate drive, are moved from the first position to the second position. When the folding wings 32, 34 are in operative connection with a drilling object, such as rock at the borehole bottom, with rotating drill head 30, a torque is generated at the folding wing 32, 34 generated transversely to Bohrkronenträgerlängsachse 70 and the folding wings 32, 34 driven from the first to the second position.

As in FIG. 3 can be seen, the flattening process 90 forming flattening is arranged parallel to the intended folding movement plane of the folding wings 32, 34.

The FIGS. 4 and 5 show a single folding wing 32, 34 as a side view ( FIG. 4 ) and in plan view ( FIG. 5 ). Cutting elements on the folding wings 32, 34 are not shown. The folding wing 32, 34 is designed as a rocker arm with a bore 46 on a foot part 48, with which the folding wings 32, 34 in the drill bit carrier 20 (FIGS. Figures 1-3 ) is pivotally mounted about a pivot axis. Such a pivot axis may be formed by a bolt 12 and is in the FIGS. 10 and 11 shown. Subsequent to the foot part 48 of the massive folding wing head 35 of the folding wing 32, 34 is formed, which in plan view ( FIG. 5 ) is formed as a circle segment. Radially inwardly from the beveled edge 38 of the folding wing head 35 extends a lug 42 which is disposed over the foot portion 48. In addition to the nose 42, a recess 44 is formed, which can receive a nose of an opposite folding wing ( FIG. 1 ). Nose 42 and recess 44 are arranged eccentrically to the center of an imaginary circumferential circle of the circular segment-shaped folding wing 32, 34. Arranged on the underside of the folding wing 32, 34 is a chamfered region 36 which, together with the region 37, forms a contact surface of the folding wing 32, 34 in the drill bit carrier, in order to enable effective force or impact transmission to the drill bit during operation.

The FIGS. 6 and 7 show a simplified drill bit 10 with two folding wings 32, 34 in the first position in one lateral sectional view through the drill bit 10 (FIG. FIG. 6 ) and in plan view of the drill bit 10 ( FIG. 7 ). The drill bit 10 is arranged in the folded state (first position) within the tube 60. The inner diameter of the tube 60 is slightly larger than the Bohrkranzdurchmesser d10. In this case, the foot part 48 of the left-side folding wing 32 protrudes below the right-side folding wing 34 and vice versa, for clarity, for example, only the one foot 48 is numbered by a reference numeral.

On the left side of the figure, a bore can be seen in the bevelled edge 38 which is intended to receive a cutting element in the form of a hard metal pin 50. For reasons of simplicity, none of the existing cutting elements are shown on the end face 40. In the first position, the radially inner edge of the chamfered edge 38 forms the most projecting edge of the drill head 30. When the chamfered edge 38 is provided with cutting elements 50, they protrude farthest in the working direction (in FIG FIG. 6 up).

The end face 40 is inclined in the first position against the Bohrkronenträgerlängsachse 70 by an angle α, wherein the end face 40 drops from outside to inside. In particular, the angle α has a value between 15 ° and 9 °, preferably between 13 ° and 11 °, particularly preferably 12 °. With an inclination of the end face 40 in this angular range, it is possible, as soon as the drill head comes into contact with the drilling object through interaction, in particular friction, with the rock to exert a torque on the folding wings 32, 34 in such a way that they move outward from the first position Move to the second position and remain there as long as the drill collar 10 rotates.

A radially outwardly disposed portion 36 on the underside of the flaps 32, 34 also has an incline relative to the drill bit carrier longitudinal axis 70, which facilitates retraction of the flaps 32, 34 from the second position to the first position. Together with the region 37, the region 36 forms a contact surface of the folding wing 32, 34 in the drill bit carrier in order to allow an effective force or impact transfer to the drill bit during operation.

The FIGS. 8 and 9 show the simplified drill bit 10 with two folding wings 32, 34 in the second position in a lateral sectional view through the drill bit 10 (FIG. FIG. 8 ) and in plan view of the drill bit 10 ( FIG. 9 ).

The end faces 40 of the folding wings 32, 34 are now positioned in the second position perpendicular to the Bohrkronenträgerlängsachse 70, so that a large work surface is formed. The cutting elements 50 on the chamfered edge 38 form an outer Bohrradius of the drill head 30. In this case, the folding wings 32, 34 with their end faces 40 to the free end of the drill bit 30 have a curvature inward, which is for the directional accuracy of drilling advantage.

The folding wings 32, 34 each have a portion 36 on the end faces 40 opposite lower sides, which is inclined in the second position by an angle β against the Bohrkronenträgerlängsachse 70, wherein the portion 36 falls from outside to inside, ie in the same direction relative to the Bohrkronenträgerlängsachse 70 is inclined as the respective end face 40 in the first position. Advantageously, the angle β has a value between 20 ° and 10 °, preferably between 18 ° and 12 °, particularly preferably 15 °. With such a slope in the region 36, the folding wings 32, 34 at a standstill Drill ring 10 are easily withdrawn into the tube 60 by the areas 36 slide on the end edges of the tube 60.

In the FIGS. 10 and 11 is a folding wing 32 in a first, folded position ( FIG. 11 ) and a second, unfolded position ( FIG. 10 ), on which the operation of the drill bit is further explained. In this case, the Bohrkronenträger 20 is shown cut. The folding wing head 35 is pivotable about the pivot axis formed by the center of the axis of rotation of a bolt 12.

Reference numeral 130 denotes in the view the highest point of the folding wing 32, which lies at the edge between the end face 40 and the chamfered edge 38. Reference numeral 120 denotes a point on the edge between the chamfered edge 38, while reference numeral 140 denotes a point on the edge between the region 36 and the lateral surface of the folding wing head 35. The points 120, 130, 140 lie in the same imaginary plane. Reference character Y denotes the radial distance of the highest point 130 from the center of the axis of rotation of the bolt 12 in the first, folded-in position. Reference numeral Z denotes the radial distance of this point 130 from the center of the axis of rotation of the bolt 12 in the second, unfolded position. Reference character C denotes the outer circumference of the drill bit carrier 20. X denotes the axial distance between the rotational axis of the pin 12 and the axial end of the drill bit carrier 20.

As long as the value Y, ie the distance between the center of the axis of rotation of the pin 12 to the highest point 130 is positive, the folding wing 32 securely moves into the second position, ie in the drilling position, in which the points 120 to 140 outside of the Bohrkronenträgers 20 (FIGS. and thus the line C in the FIG. 10 ) lie. This applies regardless of the head shape of the folding wing head 35th

The larger the value Y, the safer the folding wing 32 works out in the drilling position.

The larger the dimension X, the smaller the angle a when the flapper 32 is collapsed within the outer periphery of the bit carrier 20, i. when points 120 to 140 are within line C).

In an embodiment not shown with two folding wings 32, 34 corresponding to the FIGS. 1 . 2 . 3 . 6 . 7 . 8, 9 can also be both folding wings 32, 34 fixed via a common bolt transverse to Bohrkronenträgerlängsachse 70 of the Bohrkronenträgers 20, wherein the axis of rotation of the bolt, the Bohrkronenträgerlängsachse 70 intersects. However, this reduces the contact surface of the folding wings 32, 34 in the region 36 and 37th

The bolt position is preferably always designed so that the folding wings 32, 34 safely unfolds and forms the largest possible contact surface on the drill bit carrier 20 for impact transmission.

reference numeral

100

drilling

10

Drill bit / drill collar

12

bolt

13

line

14

bolt

20

drill bit

22

drilling

24

drilling

30

wellhead

32

folding wings

34

folding wings

35

Folding wings head

36

Area bearing surface

37

Area bearing surface

38

bevelled edge

40

face

42

nose

44

Recess / recess

46

drilling

48

footboard

50

Cutters / hard metal pin

60

pipe

70

Bohrkronenträgerlängsachse

80

coupling

90

Bohrmehlablauf

120

first point

130

second point

140

third point

d10

Drill bit / Bohrkranzdurchmesser

Claims (10)

1. Rotary percussion drill bit which, after running through an outer casing, upon ground contact, opens, automatically folds out and drills to a larger dimension than the diameter of the outer casing, wherein

   - the movable parts of the rotary percussion drill bit are rotatably mounted transversely with respect to the bit shaft,

   - form a drilling head,

   - the rotary percussion drill bit has the energy required for drilling supplied by hydraulic hammers or down-the-hole hammers,

   - to change rods or after work is completed, the rotary percussion drill bit can be simply retracted into the outer tube without rotation against the working direction of rotation,

   - the movable parts comprise at least two swing wings (32, 34),

   - characterized in that each of the swing wings (32, 34) comprises a swing wing head (35) formed in the manner of a circular segment, wherein each swing wing (32, 34)

   - has an end face (40) with a radially outwardly arranged bevelled edge (38), and a nose (42) which extends radially inwards from the bevelled edge (38), wherein a recess (44) is formed next to the nose (42) and can receive the nose (42) of the opposite swing wing (32, 34), wherein

   - cutting elements (50) are inserted on the end face (40) and the bevelled edge (38).
2. Drill bit (10), having a drilling head (30) and a drill bit carrier (20) which bears the drilling head (30), having at least two swing wings (32, 34) which can be moved back and forth between a first position and a second position, wherein each of the swing wings (32, 34) is arranged within a drill bit diameter (d10) in the first position and projects beyond the drill bit diameter (d10) in the second position, and wherein each of the swing wings (32, 34) has an end face (40) at its free end, each of the swing wings (32, 34) is arranged on the drill bit carrier (20) so as to be pivotable transversely with respect to a drill bit carrier longitudinal axis (70) about a pivot axis in the form of a bolt (12, 14) and is structurally designed in such a way that, with the drilling head (30) rotating, an active connection with an object to be drilled generates a torque on the swing wing (32, 34) transversely with respect to the drill bit carrier longitudinal axis (70) and drives the swing wing (32, 34) from the first into the second position,
   characterized in that

   - each of the swing wings (32, 34) is formed in the manner of a circular segment on its swing wing head (35), and

   - has an end face (40) with a radially outwardly arranged bevelled edge (38) and a nose (42) which extends radially inwards from the bevelled edge (38), wherein a recess (44) is formed next to the nose (42) and can receive the nose (42) of the opposite swing wing (32, 34), wherein

   - cutting elements (50) are inserted on the end face (40) and the bevelled edge (38).
3. Drill bit according to Claim 2, characterized in that the end face (40) is inclined by an angle (α) with respect to the drill bit carrier longitudinal axis (70) in the first position, wherein the end face (40) slopes down from outside to inside.
4. Drill bit according to Claim 2 or 3, characterized in that, in the first position, the radial distance (Y) of the highest point (130) of each swing wing (32, 34) from the pivot axis has a positive value.
5. Drill bit according to one of the preceding claims, characterized in that, each of the swing wings (32, 34) has, on its lower side opposite the end face (40), a region (36) which is inclined by an angle (β) with respect to the drill bit carrier longitudinal axis (70) in the second position, wherein the region (36) slopes down from outside to inside.
6. Drill bit according to Claim 5, characterized in that the angle (β) has a value between 20° and 10°.
7. Drill bit according to one of the preceding claims, characterized in that the bevelled edge (38) forms an outer drilling diameter in the second position.
8. Drill bit according to one of the preceding claims, characterized in that at least one flushing medium feed is provided within the drill bit carrier (20).
9. Drilling device (100) having a drill bit (10) according to one of the preceding claims, characterized in that the drill bit (10) is guided or can be guided in a tube (60).
10. Drilling device according to Claim 9, characterized in that the drill bit carrier is coupled or can be coupled to an output shaft (80) in a rotationally fixed manner.

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