DE2512652A1 - DRILL HEAD FOR ROTATING PERFECT DRILLING - Google Patents

Description

Munich 05/18/75

UT 25ο§ P

SS = SSSSSS

Padley & Venables Limited,
Callywhite Lane, Dronfield,
Sheffield, S18 6XT, England,
Great Britain

Drill head for rotating percussive drilling

The invention relates to a drill head, a so-called mining chisel for rotating percussive drilling or impact drilling. It is essentially concerned with the shape and the arrangement of the cutting inserts, the so-called drill bits.

Percussive drilling, in which the breaking of the rock is seen by drilling by smashing the rock with the Drill head is produced during the intermittent rotation of the notches, which are therefore closely adjacent to one another, also known as push drilling. The rock broken in this way, the cuttings, is also in removed in a known manner, for example by means of a pressure on the forehead or on a side surface from the drill head emerging flushing fluid with which the cuttings between the outside of the drill head and the wall of the borehole is brought through out of the borehole.

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Devices for percussive drilling have a rotating switching movement for the drill head, with which the drill rod, the carries the drill head, is rotated through a predetermined angle between successive impacts. Rotating beating Drilling is preferred because it has a smaller number of cutting inserts and also smaller cutting inserts on the Drill head are required than for non-rotating percussive drilling.

It was common practice to use machines with mechanical indexing rotary motion to be used, i.e. with intermittent rotation between successive strokes. The cutting inserts had to be designed to be resistant to blows alone, because the rotation was only possible from the (The drill head was loosened from the stone surface.

More recent developments, however, are aimed at driving the drill head independently - of the blows - and thus continuously, while at the same time striking impacts are introduced into the drill head to shatter the rock.

The invention is based on the object of creating a drill head which meets the requirements of recent practice, which is therefore suitable for use with continuous turning, which is superimposed with the blows.

In the case of a drill head for rotating percussive drilling, with a longitudinal axis and an end face as well as in its body fastened cutting inserts protruding from the end face in the axial direction is the object of the invention solved in that each of the cutting inserts a flat

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Chest has that the chest lies in a plane parallel to the longitudinal axis and thus the angle of attack is the same zero is that all breasts show in the same way in the direction of rotation of the drill head that each breast in the axial direction protrudes over the face of the head with a front cutting edge and a free surface that the free surface extends approximately perpendicular to the longitudinal axis, such that the stress or wear when rotating percussive drilling affects the free surface and thus the cutting edge is largely protected. The cutting inserts are preferred of elongated shape and so arranged that their largest dimension or length is mainly in to the Head extends radial direction.

The terms "forward" and "forward direction" are intended to provide the Designate the direction in which the drill head advanced into the rock is, briefly the drilling direction. If it is further said that the breast lies in a plane parallel to the longitudinal axis, a deviation of up to a slope of about 5 should be included. A slope should be aimed for less than up to 2 ° in both directions. Even in cases where the chest is not in one to the If the plane is parallel to the longitudinal axis, the cutting edge should lead in the direction of rotation.

In the drill head according to the invention it is provided that rock is broken away as a result of the rotating force, the has previously been blown up by the blow.

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The open areas are expediently designed to be flat so that they always have straight cutting edges. The chest is useful and to arrange the free space to each other at a first angle of 80 to 87 ° if possible. Drilling tests have shown that with cutting inserts of the geometrical configuration described above, this first angle in use can be sustained. It is thus to be expected that the cutting edge will last for the life of the cutting insert resharpening is not required.

Opposite the cutting edge, a rear surface with a slightly more acute angle to the chest should form on the free surface, a second angle, which should preferably be 5o to 8o °.

Drilling tests with drill heads according to the invention and the preferred angular graduations of the chest, the open area and the rear surfaces have shown that they bounce far less from the rock surface between the impacts than the previously known drill heads. This is a great benefit because it reduces rebound A standing engagement of the cutting edge allows the material to be cut, with larger chunks or particles being loosened which in turn reduces the amount of dust and ultimately the removal of the cuttings is relieved from the borehole. This phenomenon is important for efficient drilling in that The chunks remaining in the hole act as cushions and dissipate the energy introduced by the impact.

In the case of the drill head according to the invention, the chest points in the direction of rotation and it protrudes from the front of the head by a hatred corresponding to the nature of the rock

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or Minerals can be chosen. This measurement will usually be between 0.1 and 0.5 cm.

The cutting inserts are preferably made from tungsten carbide or another hard material, but not mandatory manufactured. The cutting inserts are fastened in their grooves in a manner known per se, for example by Brazing or a shrinking process. Usually have the cutting inserts have an elongated shape and they protrude radially from the side wall of the head. It can be any AT »7-ah1 cutting inserts, usually 2, 3, 4, 5 or 6 are provided be, these are distributed on a circumference around the longitudinal axis, depending on the requirements of a drilling operation. Nevertheless, according to the invention, cutting inserts other than elongated and radially arranged cutting inserts can also be provided, see above of round or polygonal cross-section, viewed axially upside down, with the breasts and the open spaces in such oblong shapes are not included.

Further protection requests result from the description, the drawing and / or the description of the prior application in Connection with the claims.

In the drawing, the invention is shown schematically and with the aid of exemplary embodiments. Show it:

Fig. 1 shows a drill head, with cutting inserts, in

a side view,

2 one of the cutting inserts in a side view,

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Pig. 3 the cutting insert, in plan view, FIG. 4 the cutting insert, in view,

Pig. 5 the drill head - according to Pig. 1 - in the front view or top view,

Pig. 5a shows an enlarged detail from FIG. 5

Scale,

FIG. 6 shows a second drill head, in an end view, FIG. 7 shows a detail of this drill head, in section

A-A according to Fig. 6,

FIG. 8 shows a third drill head, in an end view, FIG. 9 shows a detail of this drill head, in section

B-B according to Fig. 8,

1o a fourth drill head, in a side view ,

11 shows this drill head in an end view, FIG. 11a shows a detail from FIG. 11 in an enlarged view

Scale,

Fig. 12 shows this drill head, in section C-C according to Fig. 11,

13 shows a detail of this drill head in the area of a cutting insert, in enlarged form Scale,

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Pig. 14 as part of this drill head - according to Fig. 1o -

a filler, in the front view, and

15 shows the filler piece, in section D-D according to FIG. 14

As far as possible, similar parts and elements are given the same reference symbols in the following description however, denoted by different symbols according to different designs.

According to FIG. 1, a drill head 1 has a hollow cylindrical shaft 2, a head 3 and a longitudinal axis 1oo. The head 3 has an end face 4. In a known manner, flushing grooves are on the head 3, distributed over its circumference with the same angular spacing 5 are provided, which extend in the axial direction, so that radially directed wing sections 6 remain. In the flushing grooves 5 open out into openings 7 for the outlet of a drilling fluid supplied through the hollow shaft 2 for flushing out of the cuttings from the borehole.

A groove 8 extending in the radial direction is provided in each of the wing sections 6. In these grooves 8 sit cutting inserts 9 made of a hard material, a so-called cutting metal, such as tungsten carbide. Every cutting insert 9 has a breast 1o pointing in the direction of rotation of the drill head 1, and an open area 11 at an acute angle so that the edge between these two surfaces represents a cutting edge 12, further adjoining the free surface 11 a rear surface 13, which forms an edge 14 with the free surface 11 and recedes with respect to the cutting edge 12. the Chest 1o protrudes over the highest or foremost point of the end face 4 or the respective Fitigelabschnitts in front of and lies in one to the. Longitudinal axis 1oo parallel plane. Further

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The chest 1o of each cutting insert 9 also stands in a radial direction Direction at point 15 across the lateral surface of the Head 3 of the drill head 1 before.

As can be seen in Fig. 1, the cutting edges 12 of all cutting inserts 9 are in a common to the Longitudinal axis 1oo vertical plane. Since this arrangement is generally preferred, it does not require a special one Explanation.

The drill head 1 is hollow along its longitudinal axis 1oo, so that during operation a - not shown - also hollow boring bar on which the drill head 1 by means a threaded portion or the like. is attached, drilling fluid directed and finally frontally and / or through openings 7 can be discharged to flush the cuttings from the borehole.

As can be seen in particular in FIGS. 2 to 4, the breast 1o represents the essential part of the front side 17 of the cutting insert. When the cutting inserts are fastened in the grooves 8 - usually by brazing or shrinking - the breast 1o has a setting angle of about 0 °, ie the angle between the rake face - the chest 1o - and the cut surface of the rock in front of the face of the drill head 1 is 90 °. All breasts 1o lie in planes parallel to the longitudinal axis 1oo. The angle between the chest 1o and the free surface 11, the clearance angle <A is approximately 8o to 87 °, preferably 83 °. The rear surface 13 is at an angle β to the chest 1o, which is between 5o and 80 ° and is preferably 55 °. The back surface 13

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extends counter to the direction of rotation to the end face 4 and this is slightly beveled at the point 16 to to have a smooth transition to the rear surface 13.

In particular according to FIGS. 3 and 4, the upper edge of the inner side surface 2o and the adjacent ones Open surface 11 and rear surface 13 a slope 19 attached, i.e. there these edges are broken in order to prevent the cutting edge 12 from breaking out during operation.

On the chest 1o form the cutting edge 12 and the radially outside lying side surface 21 of the cutting insert 9 an acute angle V, so that a secondary cutting edge 22 on the radially in front of Btenden Section 24 of the chest 1o exists, which is narrower than the bore hole created by the drill head 1 whose wall recedes. The corner opposite the incline 19 between the cutting edge 12 and the secondary cutting edge 22 is broken or provided with an arcuate transition 23 in order to break out a corner that would otherwise exist there to prevent. The cutting edge 12 and the secondary cutting edge 22 are at an acute angle ν to each other about a joint backward facing cutting cone. The angle is between 8o and 89 °, it is preferably 87 °, such as shown.

The drill head 1 is for working - counter to the machine provided clockwise, which is why the cutting edges 12, when looking against the face of FIG. 5 in a clockwise direction demonstrate.

- 1o -

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- 1ο -

Since the cutting inserts 9 are arranged in a radial extension to the longitudinal axis 1oo, their chest 1o lies in a plane parallel to the longitudinal axis 1oo, but not in a plane containing the longitudinal axis but in a plane in addition plane-parallel plane lying in front of it in the direction of rotation.

This means that the breast 1o is angled at an acute angle to an imaginary plane 1o1 containing both its outer edge and the longitudinal axis 1oo. The angle ^/ IT 'should not be greater than 30 ° and preferably between 5 and 10 °. In general, a part of the breast 1o and the cutting edge 12 should protrude laterally beyond the end face 4 for free cutting. However, designs are also to be considered in which the or a part of the cutting inserts do not protrude beyond the outer corner. In such designs, the angle IT is understood to be located between the assumed chest and the imaginary plane 1o1, this plane intersecting the outer corner of the end face at the imaginary extension of the chest.

Another possibility for the geometric determination of the breasts of the cutting inserts results - according to FIGS. 5 and 5a - in that the breast 1o lies plane-parallel to an imaginary plane 1o2 containing the longitudinal axis 1oo and in the direction of rotation in front of this plane 1o2, with between the there is a distance * between plane-parallel planes. This distance pe should generally not be greater than - and preferably ^ι -, 'where d is the diameter of the hole to be drilled.

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As stated above, the secondary cutting edge 22 with transition 23 and in part the cutting edge 12 offer free cutting when the drill head 1 is used. The angle Ϋ between the breast 1o and the outer side surface 21 is set so that the edge 25 of the side surface 21, which is at the rear in the direction of rotation, is set back from the minor cutting edge 22, and that the side surface 21 at its rear edge 25 on an edge 26 of a section 27 of the wing section 6 meets and in this way goes over gently.

In Pig. 6 and 7, all objects which are the same or similar to the parts described above are given the same reference symbols, but are provided with the additional symbol a. Sit there there in the end face 4a cutting inserts 9a, the chest 1oa of which is set back relative to the front side surface 17a, that the breast 1oa lies in a plane containing the longitudinal axis 1ooa. The cutting edge 12a is thus radial to the Longitudinal axis 1ooa, the edge 14a parallel to it. The grooves 8a and the portion of the cutting inserts 9a seated therein correspond to the design according to FIGS. 1 to 5.

The breast 1oa forms with the front side surface 17a - viewed in the axial direction - a triangular recess 28, the greatest width of which is on the inner side surface 2oa and which ends at the secondary cutting edge 22a. The chest 1oa projects beyond the axially outermost point 29 of the end face 4a of the drill head 1a. In the case of the cutting insert 9a, the angles cL and β expediently correspond to the dimensions already discussed above.

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In Pig. 8 and FIG. 9 are provided with the suffix b to those already described similar or identical parts. The grooves 86 and the sections of the cutting inserts 9b seated therein are unchanged. The breasts 1ob lie in a plane containing the longitudinal axis 1oob, they are set back by a recess 28b extending in the radial direction with a constant cross-section relative to the front side surface 17b. The cutting edges 12b lie radially to the longitudinal axis 10ob and protrude in the axial direction beyond the end face 4b. The angles a1 and β are the same or similar to those described above.

In a fourth embodiment of a drill head 1c according to FIG. 10 to FIG. 15, all identical or similar parts are provided with reference symbols as before, but with the additional symbol "c". Cutting inserts 9c, the profile of which is very similar to that of the cutting inserts according to FIGS. 1 to 5, are accommodated in the end face 4c. The cutting inserts 9c sit in grooves 8c, which are, however, set back from a radial plane, so that the breasts 1oc lying in the same plane with the front side surface 17c and at the same time the cutting edges 12c lie together in a plane behind the plane containing the longitudinal axis 1ooc in the direction of rotation Are arranged level. In the case of an imaginary radial plane 1o1c which intersects the outer edge of the cutting edge 12c, the cutting edge 12c or the breast 1oc forms an angle to this plane 1o1c. In this embodiment, the outer edge of the cutting edge 12c leads its other sections. The angle IO should not be greater than 30 ° and preferably be 5 to 10 °. As has been dealt with in detail in connection with FIG. 5, if some cutting inserts 9a do not protrude radially, when dimensioning the angle CJ, an imaginary, radially protruding extension should be

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be gone. Here, too, is another geometric one Determination of the location of the cutting edge 12c or the chest 1oc possible in that the distance y between a plane 1o2c containing the longitudinal axis 1ooc and a plane parallel to it, in the direction of rotation, the plane containing the breast 1oc and the cutting edge 12c is indicated. The distance y should not be greater than - and preferably be.

The geometrical position of the cutting inserts described above 9c in the fourth example appears to be particularly advantageous because this is compared to the previously described Embodiments tend to reduce the shear force exerted on the cutting inserts 9c during use of the drill head acts. Furthermore, the geometric arrangement, as described above, appears particularly favorable, in order to promote the flow of detergent from the opening 16c in the center of the end face 4c.

in

For manufacturing reasons, the drill head 1c, narrower its head 3c, has a bore 3o opposite the neutral bore 16c attached, so that a space is created for the outlet of the cutting tools when producing the grooves 8c. After manufacture of the grooves 8c, according to FIG. 12, a filler piece 31 in the hole 3o used, which has a breakthrough as a port setting of the hole 16c, a substantially the hole 3o has a corresponding outer profile, with the exception of four recesses 32, which correspond to the grooves 8c in such a way that that the radially inner end sections of the cutting inserts 9c engage in the recesses 32. After insertion of the filler piece 31 and the cutting inserts 9c, these are secured by brazing.

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-H-

In the embodiment according to FIG. 1o to FIG. 15, the angle is advantageously oC
the angle ^ about 70 °,

partly the angle oC about 81 °, the angle A about 6o ° and

It should be noted that the corresponding portions of the cutting inserts 9, 9a, 9b and 9c and the grooves 8 to 8c with drill heads of similar dimensions have the same dimensions and profiles, so that they are interchangeable and can be combined in a drill head if necessary.

In the invention, the geometric relationship between the breast 1o and the flank 11 and the cutting edge 12 is from FIG weighty importance. When operating drill heads according to the invention with intermittent impacts and intermittent impacts or continuous rotation, the rock is blasted by means of the blades 12 and over the breasts 1o broken away. Another advantage of the design according to the invention, the geometric shape and the angular relationship between the breasts 1o and the free surfaces 11 of the cutting inserts 9 shows itself in a self-sharpening effect on the cutting edges 12, in particular their leading points 29 when in use. The geometric ones are similarly advantageous Shape and the angular relationship between the breasts and the minor cutting edges 21 in terms of a self-sharpening effect when using the drill head.

The invention is not restricted to the number of four cutting inserts. Rather, a different number of cutting inserts can also be used be chosen. Likewise, not all cutting inserts have to go radially or laterally over the side wall of the head protruding. Cases of use are certainly conceivable in which none or only some of the cutting inserts protrude laterally.

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Drilling tests have shown that under the same conditions with drill heads according to the invention, significantly higher drilling capacities can be achieved than with conventional drill heads with symmetrically tapered cutting inserts.

Claims: - 16 -

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Claims (1)

Claims; 1. Drill head for rotating percussive drilling, with a longitudinal axis and an end face as well as in its body fastened cutting inserts protruding from the end face in the axial direction, characterized that each of the Senneid inserts has a flat chest that the chest in one to. the Longitudinal axis is parallel plane and thus the angle of attack is zero, that all breasts in the same Way in the direction of rotation of the drill head show that each breast in the axial direction over the face of the head with a front cutting edge and a free surface protrudes that the free surface is approximately perpendicular to extends the longitudinal axis in such a way that the stress or wear during the rotating percussion Drilling has an effect on the open area and thus the cutting edge is largely spared. 2. Drill head according to claim 1, characterized in that the free surface (11) is flat, around a straight Cutting edge (12) * 3. Drill head according to claim 1 or claim 2, characterized in that that there is a first angle between the chest (1o) and the free surface (11), that this angle (oL) is acute and that this angle exists on at least one cutting insert (9). - 17 - 509839/0370 4. Drill head according to claim 3, characterized in that the first angle (<λ) is between 8o ° and 87 °. 5. Drill head according to claim 4, characterized in that the first angle (<£) is approximately 83 °. 6. Drill head according to one of claims 1 to 5, characterized in that that at least one of the cutting inserts (9) with one of the free surface (11) to that of the Breast (1o) opposite side surface (26) extending rear surface (13) is provided, wherein this to the chest (1o) at a second acute angle (/ b). 7. Drill head according to claim 6, characterized in that the second acute angle (ß) is smaller than the first acute angle (el). 8. Drill head according to one of claims 6 or 7, characterized in that that the second acute angle is in the range between 5o ° and 8o °. 9. Drill head according to claim 8, characterized in that the second acute angle (ß) is about 55 °. 1o. Drilling head according to one of Claims 6 to 9, characterized in that that the rear surface (13) extends in the direction of the end face (4) and that the last locally is bevelled to make a smooth transition to the rear surface (13). - 18 - 509839/0370 11. Drill head according to one of claims 1 to 1o, characterized in that that the chest (1o) of at least one cutting insert (9) in the axial direction from the end face (4) protrudes, preferably by 0.1 to 0.5 cm. 12. Drilling head according to one of claims 1 to 11, characterized in that that the cutting edges (12) lie together in a plane approximately perpendicular to the longitudinal axis (1oo). 13. Drilling head according to one of claims 1 to 12, characterized in that that the cutting edge (12) of at least one cutting insert (9) is in a plane which is plane-parallel to a plane (1o2) containing the longitudinal axis (loo). 14. Drilling head according to one of claims 1 to 13, characterized in that that an arrangement is made for the cutting edge (12) at least one cutting insert (9) at which the cutting edge (12) or an imaginary line as an extension of the outer edge of the end face (4) in one imaginary plane intersects which is parallel to a plane containing the longitudinal axis (1o2), and that the Cutting edge (12) to such an imaginary plane at a third angle (TT) is such that the inner Section of the cutting edge (12) rushes ahead of the outer corner of the cutting edge (12) in the direction of rotation. 15. Drill head according to claim 14, characterized in that the dr
lies. the third angle (ψ) in the range between 5 ° and 3o ° - 19 - 509839/0370 16. Drill head according to claim 15, characterized in that the angle ("Π") is about 1o °. 17. Drilling head according to one of claims 1 to 16, characterized in that for the cutting edge (12c) at least one cutting insert (9c) an arrangement is made in which the cutting edge (12c) or an imaginary line in its extension, the outer edge of the end face (4c) cuts in an imaginary plane which lies parallel to a plane (1o2c) containing the longitudinal axis, and that the cutting edge (12c ) lies at a fourth angle ((O) to such an imaginary plane, such that the outer Corner of the cutting edge (12c) leads the radially inner section of the sonic edge (12c) in the direction of erection. 18. Drilling head according to claim 17, characterized in that the fourth acute angle (to) between the cutting edge (12c) and the imaginary plane is between 5 ° and 3o °. 19. Drill head according to claim 18, characterized in that the fourth angle (u) is about 1o °. 20. Drilling head according to one of claims 1 to 19, characterized in that that the chest (1o) of at least one cutting insert is part of the front side surface (17). 21. Drilling head according to one of claims 1 to 19, characterized in that that the chest (ioa) of at least one cutting insert (9a) partially has a groove (28) in the cutting insert forms. - 2o - 509839/0370 - 2ο - 22. Drilling head according to claim 21, characterized in that the flute (28) extends axially to below the end face (4a) extends. 23. Drilling head according to one of claims 1 to 22, characterized in that that the chest (1o) at least one of the cutting inserts (9) in the radial direction over the Side surface of the head (3) also extends, and that the radially protruding portion of the chest (1o) a mainly axially directed secondary sun silk (22) - for Free cutting - contains. 24. Drill head according to claim 23, characterized in that the cutting edge (12) and the secondary cutting edge (22) by means a beveled or arcuate transition (23) merge into one another to prevent a breakout there to forestall an otherwise sharp corner. 25., drill head according to claim 23 or claim 24, characterized in that that the secondary cutting edge (22) is designed to recede counter to the drilling direction and consequently is at a fifth acute angle (y) to the cutting edge (12). 26 ". Drill head according to claim 25, characterized in that the fifth acute angle (v) is in the range between 80 ° and 89 °. 27. Drill head according to claim 26, 'characterized in that the fifth acute angle (v) is about 87 °. 28. Drilling head according to one of claims 23 to 27, characterized in that the radially outer side surface (21) from the secondary tendon (22) is designed to be inclined into the side surface (27) of the head (3). 509839/0370 - 21 - 29. Drill head according to one of the claims. 1 to 28, characterized in that that the cutting inserts (9b) have an elongated shape and in the direction of their greatest extent are arranged radially to the longitudinal axis (1oob) in the head (3b). 30. Drill head according to claim 29, characterized in that the cutting inserts (9b) are arranged in radially directed wing sections (6b) of the head (3b). 31. Drilling head according to one of claims 1 to 3o, characterized in that that in the head (3) a bore (16), a channel or the like. is provided with at least one opening, through which a drilling fluid can be passed to remove the cuttings. 32. Drilling head according to claim 31, characterized in that the opening (16) and the cutting inserts are approximately centric (9) are arranged approximately circularly symmetrically around the opening (16). 509839/0370