EP0583629B1 - Core bit comprising removable toothed elements with a peripheral distribution - Google Patents

Abstract

Core bit, in particular for drill tubes, with an annular basic body (1) which can be welded to a drill tube or a coupling. Toothed elements (30) arranged in a peripherally distributed manner are attached to the basic body (1) by welding or by push-in connections in such a way that the surfaces for the fastening welds or the push-in connection faces lie on a plane circle relative to the bottom edge (18) of the basic body, the toothed elements having: a) a slightly curved connection face (31), adapted to the drill-tube diameter, for the connection to the bottom edge of the basic body; b) a virtually plane rear face (32) running at a right angle or an acute angle to this face; c) a continuously curved working face (33) which adjoins the connection face and the rear face, connects these faces, defines an angular range between about 180 DEG and 270 DEG and is provided with a number of embedded carbide end pins (29) or tips (28) distributed over the face and projecting by about 1.5 to 2.0 mm from the surrounding surface; d) two end faces (34) which terminate the above-mentioned faces on both sides and form an angle of less than 90 DEG to the connection face. <IMAGE>

Description

The invention relates to a drill bit with circumferentially distributed, Detachably arranged tooth bodies, especially for drill pipes.

Drill bits are known in particular for double-walled drill pipes with common diameters from 600 mm to 2000 mm. These consist of a cast steel body with crown teeth and a coupling part for connection to the Drill pipe string. With known drill bits, the teeth are by flame cutting from a rolled mild steel blank shaped and heightened by welding and then with a Armored wear welding. With these crowns are the worn or broken teeth through So-called layer welding rebuilt from bottom to top and armored and reground. If the wear armor is only partially to be replaced, the worn one is first Armor ground down, then by body welding the basic tooth shape is restored and then the wear armor upset. This work can only exceptionally be carried out on site, they require also a workshop workload of approx. one to two hours of work per tooth.

In other known drill bits there are complete tooth units with external cut-out cutters and internal tooth back in deep indentations in the main body of the drill bit shrink wrapped. Because of this design are very long and deep welds required.

If worn teeth are to be replaced with this type of construction, so it is cumbersome and lengthy, these big welds to remove the bulges to accommodate new ones Clear and prepare dental units. The welding in of the new tooth units takes a long time and Workload. This extensive work can also not be carried out on the construction site, but instead the drill pipes or drill bits must be refurbished in a workshop.

The invention relates to an improved Drill bit that is slightly different from the Drill pipe can be loosened and the strongest Tooth bodies exposed to wear with minimal time and Labor costs are replaceable. This work is on the Construction site feasible.

To solve this problem, an annular one was attached to a drill pipe or a coupling of weldable base body is proposed, molded onto the spaced-apart tooth lugs on which the tooth bodies can be exchanged by welding are set in such a way that all weld seams to the lower edge of the base body on a flat circular line lie.

Instead of welding seams, plug connections can also be used or locks for the mechanical attachment of the tooth body come into consideration at the lower edge of the base body.

a) einer dem Bohrrohrdurchmesser angepassten leicht gekrümmten Anschlussfläche für die Schweiss- oder Steckverbindung zu der auf einer ebenen Kreislinie liegenden Unterkante oder deren Zahn-Ansätzen des Grundkörpers,

b) einer im rechten oder spitzen Winkel zu dieser Fläche verlaufenden nahezu ebenen Rückenfläche,

c) einer an die Anschlussfläche und an die Rückenfläche anschliessende, diese verbindende, einen Winkelbereich zwischen ca. 180° und 270° umschreibende, stetig gekrümmte Arbeitsfläche, die flächenverteilt mit einer Anzahl von eingelassenen, etwa um 1,5 bis 2,0 mm aus der umgebenden Fläche heraustretenden Hartmetall-Stirnstiften versehen ist,

d) zwei die obengenannten Flächen beidseitig abschliessenden Stirnflächen, die zu der Anschlussfläche einen Winkel kleiner 90° bilden.

The invention is based on this embodiment according to DE 39 33 867 A1, and it consists of a tooth body with

a) a slightly curved connection surface adapted to the diameter of the drill pipe for the welded or plug-in connection to the lower edge lying on a flat circular line or its tooth attachments of the base body,

b) an almost flat back surface running at a right or acute angle to this surface,

c) a continuously curved work surface which adjoins the connecting surface and the back surface and connects them, circumscribing an angular range between approximately 180 ° and 270 °, which is distributed with a number of recessed surfaces, approximately by 1.5 to 2.0 mm carbide end pins emerging from the surrounding surface are provided,

d) two end faces which close off the abovementioned surfaces on both sides and form an angle of less than 90 ° to the connection surface.

c') einer an die Anschlussfläche und an die Rückenfläche anschliessende, diese verbindende, einen Winkelbereich zwischen ca. 180° und 270° umschreibende, stetig gekrümmte Arbeitsfläche, in die eine Anzahl von Hartmetall-Platten eingelassen ist, die etwa um 1,5 bis 2,0 mm aus der gekrümmten Arbeitsfläche heraustreten.

A modified solution, which also starts from DE 39 33 867 A1, consists of a tooth body with the identical features a), b) and d), and with

c ') a continuously curved work surface connecting to the connection surface and to the back surface, connecting these, circumscribing an angular range between approximately 180 ° and 270 °, into which a number of hard metal plates is embedded, which is approximately 1.5 to Step 2.0 mm out of the curved work surface.

This drill bit with the features designed according to the invention compared to the known designs as well generic drill bit a significant advance represents. While the drill pipes with the according to the generic State of the art shaped pre-welded tooth body with hard metal pins are ideal for cutting if they also have certain milling properties new design according to the invention preferably for milling use suitable, although they also have good cutting properties owns; it can therefore be used more universally.

This also applies to known drill bits, for example according to DE 36 00 189 C2, which is mainly for milling Jacking can be used. There are also drill bits with cleat teeth used for milling in hard soils, where the outer surfaces of the teeth are in the direction of the Outer shell of the drill pipe run and to achieve of a free cut effect, so that only a milling track corresponding to the tooth width is generated.

When using these known drill bits, it has been shown that often, with changing soil conditions of very Hard to stiff or solid plastic consistency, only slight or no piping progress is made can. If the drill pipe is then to be pulled, act the protruding teeth like barbs; this well-known Tooth shapes are neither cut back nor show they have a cutting effect for the pipe feed at binding Floors on.

These disadvantages become apparent with the new configuration of the drill pipes largely avoided with the tooth bodies. The two-sided End faces are opposite the connection areas forming an acute angle inclined and sharp-edged opposite the work surface describing an approximately oval circumferential line, so that a cutting-like contour is created. If there are two inclined surfaces after an additional feature connect the cutting-like end faces, then this will a clearing room for the cut and loosened floor Approved.

The service life of these cut edges is increased considerably, if this is based on a proposal with welding armor made of a wear-resistant material will. The end faces can also be large armored and also armored with a hard metal plate.

A significant feature is that some the tooth body at an angle β between. 5 ° and 25 ° behind outside and some tooth bodies at an angle γ between 5 ° and 25 ° inclined inwards with the lower edge or its Tooth approaches of the main body are connected, it being special can be advantageous if the tooth body alternately connected to the base body inclined inwards and outwards are.

This entanglement of the tooth body is sufficient large pre-cut and free cut achieved so that the drill pipes pulled without difficulty at any time or progressing Drilling process can be adjusted.

The shaping of the tooth body - to a tube-axial, the Plane axis intersecting plane symmetrical - brings the extraordinary Advantage with it that drilling both rotating as well as oscillating, preferably alternating, can be done without getting stuck of the drill pipe comes. Over the tooth body inclined outwards becomes a back milling as well as a back cutting effect achieved and the leading for feeding Soil material is over the sloping surfaces and tooth gaps mentioned led away and removed inside. Even at Feeding through rock deposits is under the effect of Carbide trimmings can be milled back.

Further advantages can result from the fact that the largest Height of the tooth body in relation to the lower edge of the base body alternately has different mass. That requires different contact pressures of the individual tooth bodies on the drilling base to be milled, which makes it, for example it is possible that individual rock deposits or chunks of Hard rock pushed away more easily and then when milling back can be removed from the milling and cutting path. Here it is advantageous that the outward inclined tooth body a greater hatred, the inward-inclined a smaller one Measure their greatest height: It results in the Drilling a step cut that makes piping progress very quickly enables.

The clearing away and displacement of loosened soil is also even easier that the lower edge of the body towards the surfaces for the fastening weld seams has a slightly tapered cross-sectional taper. Furthermore, in the area of cross-sectional tapering elevations serving as interior clearers are appropriate, which are welded hard armor or with Weld-on hard armor can be provided.

The tooth bodies are expediently in the region of their connecting surfaces and a subsequent surface section of their back surfaces on the core bit body or on a plug connection to be releasably anchored in the core bit body welded on. But also the attachment of the tooth body Using releasable locks can be an advantage be.

Another significant advantage of the drill bit according to the invention is that the semicircular basic shape of the milling track with its radius of curvature is also maintained that the tooth body alternately set against each other, i.e. in different angular positions to the vertical are arranged.

According to further important features of the invention Tooth body, which is provided with hard metal plates these plates are pipe-radial, i.e. perpendicular to the pipe wall and thus perpendicular to the directions of movement of the tooth body, covering the entire curvature of the work surface in these admitted. This provides, with good stability, the Tungsten carbide plates, a milling effect all over Safe working surface on the drill base.

It is for the milling property of the tooth body Advantage if the surfaces of the hard metal plates are sawtooth-like are beveled, preferably one half each Tungsten carbide plates in one of the two directions of movement.

Fig. 1

einen Zahnkörper aus Richtung A gem. Fig. 2;

Fig. 2

einen Zahnkörper aus Richtung B gem. Fig. 1;

Fig. 3

einen Zahnkörper aus Richtung C gem. Fig. 2;

Fig. 4

einen Zahnkörper in Draufsicht gem. den Fig. 1 und 3;

Fig. 5

eine perspektivische Teilansicht von der Unterkante des Grundkörpers;

Fig. 6

einen Teilschnitt durch die Unterkante des Grundkörpers;

Fig. 7

einen anderen Teilschnitt durch die Unterkante des Grundkörpers;

Fig. 8

einen Schnitt durch einen Zahnkörper in einer anderen Ausführung;

Fig. 9

einen Zahnkörper aus Richtung A gem. Fig. 10;

Fig. 10

einen Zahnkörper aus Richtung B gem. Fig. 9;

Fig. 11

einen Zahnkörper aus Richtung C gem. Fig. 10.

The invention is described and explained below with its essential features using the exemplary embodiment shown in the drawing. Show it

Fig. 1

a tooth body from direction A acc. Fig. 2;

Fig. 2

a tooth body from direction B acc. Fig. 1;

Fig. 3

a tooth body from direction C acc. Fig. 2;

Fig. 4

a tooth body according to plan view. 1 and 3;

Fig. 5

a partial perspective view of the lower edge of the base body;

Fig. 6

a partial section through the lower edge of the base body;

Fig. 7

another partial section through the lower edge of the base body;

Fig. 8

a section through a tooth body in another embodiment;

Fig. 9

a tooth body from direction A acc. Fig. 10;

Fig. 10

a tooth body from direction B acc. Fig. 9;

Fig. 11

a tooth body from direction C acc. Fig. 10.

In Figure 1, the symmetrical, acute-angled position of the End faces 34 to the connecting surface 31 clearly. The edges between the end faces 34 and the working surface 33, or of the trapezoidal, adjoining the work surface 33 almost flat surface section 35 are hard-armored. In the curved working surface 33 there are several hard metal face pins 29 fitted.

Figure 2 shows the connection surface 31 and the back surface 32 as a throat for receiving the weld seam. The one in her curved Section of almost cylindrical part-shaped work surface 33 sweeps an angle of 180 °, making several Tungsten Carbide Face Pins 29 Contains; you almost level Surface section 35 is at an obtuse angle to the connection surface 31. The sloping surface 36 intersects the end face towards the back surface 32 in such a way that the end face outline 37 receives a hook-like contour.

FIG. 3 illustrates the shape of the inclined surfaces 36: on the back surface 32 and the part of the abutting it Work surface 33, and on both sides of the end surfaces 34 then they are slightly concave.

Figure 4 shows the concave course of the inclined surfaces more clearly 36, recognizable by the course of the edge between the Sloping surfaces 36 and the back surface 32. On the shape of the Terminal area 31 shows the diameter of the drill pipe adapted slight curvature of the tooth body. The in the work area fitted carbide end pins 29 are with her protruding beyond the outside of the tooth body Part visible.

Figure 5 illustrates the attachment of the tooth body 30 on the Lower edge 18 of the core bit body 1, and the position the working surfaces 33 and the end surfaces 34 in their operative position. The base body 1 points towards the lower edge 18 slightly tapered cross-sectional taper 15.

Above the welded tooth bodies are in this area serving as a free cut dreamer 10, its function appropriately shaped ridges attached.

The setting of the tooth body on the core bit body 1, as well as the resulting free cut in the drilling base, is shown in Figures 6 and 7. The tooth body in Figure 6, with inclined surface 36, almost flat surface section 35, end face 34 and work surface 33 and the carbide end pins 29 fitted therein is one Angle β outwards, the tooth body in Figure 7 by an angle inclined inwards. The attachment of the tooth body by means of a welded joint 14 on the tooth lugs 3 of the The drill bit is illustrated as well as the advantageous one Effect of the radial arrangement of the hard metal face pins 29 in the bottom of the hole. The one for the cutting and milling properties important difference in the greatest height of the tooth body h1 and h2, respectively, can also be seen in FIGS. 6 and 7.

In Figure 8, the tooth body 30 is by a welded connection 14 connected to the plug shaft 13. This is with provided a mounting hole 16 with which it can be detached can be anchored in the base body 1.

Figures 9, 10 and 11 show an embodiment of the Tooth body according to claim 2. This tooth body corresponds that of Figures 1 to 4, wherein instead of the hard metal face pins four hard metal plates 28 in the work surface 33 are let in. Figure 10 illustrates the curvature of the work surface adapted surface curvature. How from 9 and 11 can be seen, are two hard metal plates 28 to the two directions of movement of the tooth body beveled.

Claims (19)

1. Core bit comprising removable toothed elements with a peripheral distribution, particularly for drill tubes, having an annular body weldable to a drill tube or a coupling and onto which are shaped in spatially distributed manner tooth shoulders, to which are detachably attached the toothed elements by welding or by plug connections in such a way that the faces for the fixing welds or the plug connection faces towards the lower edge of the body are located on a planar circular line, characterized by tooth elements (30) having

   a) a slightly curved connecting surface (31), adapted to the drill tube diameter, for the plug or welded joint (14) to the lower edge (18) or the tooth shoulders (3) of the body (1) located on a planar circular line,

   b) an almost planar back face (32) at a right or an acute angle (α) to said face (31),

   c) a continuously curved working face (33) describing an angular range between approximately 180° and 270° connecting to the connecting face (31) and to the back face (32), linking the latter, being provided in surface-distributed manner with a plurality of recesses carbide end pins (29) passing out of the surrounding surface by approximately 1.5 to 2.0 mm,

   d) two end faces (34) terminating on either side said faces (31, 32, 33) and which are inclined to one another and form an angle smaller than 90° to the connecting face (31).
2. Core bit comprising removable toothed elements with a peripheral distribution, particularly for drill tubes, having an annular body weldable to a drill tube or a coupling and onto which are shaped in spatially distributed manner tooth shoulders, to which are detachably attached the toothed elements by welding or by plug connections in such a way that the faces for the fixing welds or the plug connection faces towards the lower edge of the body are located on a planar circular line, characterized by tooth elements (30) having

   a) a slightly curved connection surface (31), adapted to the drill tube diameter, for the plug or welded joint (14) to the lower edge (18) or the tooth shoulders (3) of the body (1) located on a planar circular line

   b) an almost planar back face (32) at a right or an acute angle (α) to said face (31),

   c) a continuously curved working face (33) describing an angular range between approximately 180° and 270° connected to the connecting face (31) and to the back face (32), linking the latter, in which is recessed a plurality of carbide plates (28) passing out of the curved working face (33) by approximately 1.5 to 2.0 mm,

   d) two end faces (34) terminating on either side said faces (31, 32, 33) and which are inclined to one another and form an angle smaller than 90° to the connecting face (31).
3. Core bit according to one of the claims 1 or 2, characterized in that between the continuously curved working face (33) describing an angular range between approximately 180° and 270° with carbide end pins (29) or carbide plates (28) and the connecting face (31) is introduced a virtually planar surface portion (35), which is at an angle thereto between 130° and 150°.
4. Core bit according to one of the claims 1 or 2, characterized by toothed elements (30), in which on the back face (32) and to the working face (33) connected thereto, as well as on either side on the end faces (34) abut two inclined faces (36), which in slightly, concavely curved manner precut the end faces (34) to the back face (32) in such a way that the end face outlines (37) acquire a hook-like contour.
5. Core bit according to one of the claims 1 or 2, characterized in that the toothed elements (30) are connected by detachable locking means to the lower edge (18) of the body (1) or to its toothed shoulders (3) with their connecting faces (31).
6. Core bit according to one of the claims 1 or 2, characterized in that in the vicinity of their connecting faces (31) and a connecting surface portion of their back faces (32) the toothed elements (30) are weldet to the lower edge (18) or toothed shoulders (3).
7. Core bit according to one of the claims 1 or 2 and at least one of the following claims, characterized in that some of the toothed elements (30) are inclined inwards by an angle (γ) between 5 and 25° and certain toothed elements (30) are inclined outwards by an angle (β) between 5 and 25° and connected to the lower edge (18) or the tooth shoulders (3) of the body (1).
8. Core bit according to claim 7, characterized in that the toothed elements (30) are inclined alternately inwards and outwards and connected to the body (1).
9. Core bit according to claims 1 and 3 or 2 and 3, characterized in that at least one of the edges between the end faces (34) and the back face (32) passing to the working face (33) is provided with a weld-on hard facing.
10. Core bit according to one of the claims 1 and 3 or 2 and 3, characterized in that at least one of the end faces (34) is provided in large surface manner with a weld-on hard facing.
11. Core bit according to claims 1 and 3 or 2 and 3, characterized in that at least one of the end faces (34) is reinforced with a carbide plate.
12. Core bit according to one of the claims 1 or 2, characterized in that the greatest height of the toothed elements (30), based on the lower edge (18) of the body, alternatively has differing values (h1/h2).
13. Core bit according to claims 7 and 12, characterized in that the greatest height (h1) of the inwardly inclined toothed elements (30) is smaller than the greatest height (h2) of the outwardly inclined toothed elements (30).
14. Core bit according to one of the claims 1 or 2, characterized in that the lower edge (18) of the body (1) has a slightly conical cross-sectional taper (15) towards the faces for the fixing welds.
15. Core bit according to claim 14, characterized in that in the vicinity of the cross-sectional taper (15) are provided protuberances serving as internal reamers (10).
16. Core bit according to claim 15, characterized in that the internal reamers (10) are constructed as a weld-on hard facing.
17. Core bit according to claim 2, characterized in that the carbide plates (28) pass in tube-radial recessed manner over the entire curvature of the working face (33).
18. Core bit according to claim 2, characterized in that the surfaces of the carbide plates (28) are chamfered in sawtooth-like manner.
19. Core bit according to claim 18, characterized in that in each case half of the carbide plates (28) are chamfered in sawtooth-like manner in the direction of one of the two movement directions of the toothed elements (30).

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