DE1944551A1 - Impact drill bit or chisel - Google Patents

Description

Impact drill bit "or chisel

The invention "relates to a percussion drill bit or chisel with a special placement or arrangement and combination of hard metal inserts on the work surface.

The known percussion bits or chisels or the like. exist from a normally forged steel body, they are mounted or actuated with striking and rotating movements break out the material on which they act.

Such percussion drill bits or chisels - hereinafter referred to as "drills" for short - can have wedge-shaped or cylindrical or button-shaped inserts in the work surface. There are already drill with a combination of wedge and button-shaped inserts known, but the buttons are arranged in the center of the drill bit, are around the central core at the bottom hole break away too _e

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Drill bits known to have only button-shaped inserts in a "certain" Have arrangement.

According to the present invention are wedge-shaped and button-shaped Inserts "in a drill combined in such a way that the effectiveness of the drill and the life of the drill be enlarged.

To this end, the invention consists essentially in the fact that in the working surface of the drill on the circumference opposite one another arranged two or more wedge-shaped inserts are arranged, which do not run radially and that in the outer area button-shaped inserts are provided on the working surface of the drill. It can also be one or more small button-shaped Inserts can be provided in the central area of the work surface for breaking away the remaining core.

An essential feature of the invention is that wedge-shaped drill bits on the one hand and button-shaped Drill bits on the other hand as primary working elements with each other Drills of this type have a greater penetration or penetration force than known drills. Even the drills according to the invention are relatively easy to manufacture.

Further advantages and features of the invention emerge from the description of an exemplary embodiment with reference to the drawing. -

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Fig. 1 shows a view of a rotary percussion drill according to the

Invention,
Fig. 2 is a view of the end face of the drill according to Mg. 1,

Fig. 3 is a section along line III - III in Fig. 2, Fig. 4 is a section along line IV - IV in Fig. 2, Fig. 5 is a section along line V - V in Fig. 2 and Fig. 6 shows a modified detail of a cutting insert.

The drill 10 consists essentially of a conical base body with a central threaded hole 12/14. The drill can also be formed directly at the front end of a drill rod.

The drill body 10 widens conically from the narrower, upper end to the thicker lower end 18, which “the working end of the drill is. The base body 10 ends in an essentially flat work surface 20. End face 20 has grooves or distributed over the circumference Slots 22 which do not run radially. The slots 22 are parallel to one another and laterally opposite one another offset. In these slots 22 hard metal inserts 24, for example made of tungsten carbide, are used. The stakes seen in cross-section have a pike-corner shape with an attached triangle. With the triangular or wedge-shaped part protrude Inserts out of slots 22. There are two of them

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Inserts 24 are provided which are diametrically opposed to one another and laterally offset from each other and at an angle to the radius.

Between the cutting inserts 24 and distributed over the circumference are cylindrical "or rod-shaped or button-shaped inserts 26 made of hard material, in particular tungsten carbide, is provided. There are four such in the exemplary embodiment cylindrical-button-shaped inserts provided. You have the Shape of cylinders with a spherical cap on top. The inserts 26 are inserted into bores 28. These holes and thus the inserts 26 run inclined to the drilling axis, so that they come into effect on the peripheral part of the drill.

The inserts can be soldered, in particular hard soldered, but also by pressing in the corresponding recesses be attached.

In the central area of the drill is a smaller button-shaped one Insert 30 inserted into a bore 32. Several such central inserts can also be provided, the axes of which can be parallel or inclined to the drill axis. The central area of the borehole bottom is machined through these inserts 30 and broken,

At least the widened lower part of the drill bit is with several axially extending channels 34 provided through v / el before the

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- 5 cuttings are easily removed.

Furthermore, through the central bore 12 and branching off from it Bores 36 compressed air for blowing the borehole bottom are supplied (Fig. 5). The holes 36 open into radial channels 38 on the face of the drill. These Channels 38 are between two button-shaped inserts 26 each intended.

The cone angle of the known with wedge-shaped or with button-shaped The drill bit provided with inserts is approximately 3 on each side (cone 6 °). However, it turned out that the life of the drill according to the invention is so much greater that it is advantageous to adjust the taper angle to make at least the lower part 18 of the drill much larger} about 6 to 8 ° on each side (i.e. 12 to 16 ° Cone angle) have proven to be advantageous ala. This larger cone angle makes it easier to regrind the circumference of the drill body when the inserts 24 are rounded or worn at their outer Efaken. Through such regrinding the original effectiveness is restored. With the larger cone angle, the material around the circumference be removed without the drill jamming in the borehole.

Another feature of the invention resides in the recesses 40- (Figs. 1 and 3) which attach axially to the wedge-shaped inserts 24 connect. Through these reliefs 40 the after-

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grinding made easier, they also indicate easier removal "or wear of the steel when the wedge-shaped inserts wear out.

In the area of the inserts 26, the end face 20 has bevels 42 provided. This makes it easier to drill the holes 28 for the inserts 26, and the inserts come out better to the effect.

Fig. 6 shows a block-shaped insert 24a, the outer The end is beveled 50. The cutting edges 52 of the inserts 24a therefore initially run at right angles to the drill axis, but are provided with bevels 50 at their outer ends. By these bevels 50 a longer service life is achieved.

with

In any case, the drill according to the invention has a cutting effect combined with a breaking or shattering effect when the drill is rotated in relation to the drill hole green and is hit at the same time.

It is of course clear that the present invention can be varied widely.

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Claims (1)

- 7 claims 1. Drill bit or chisel, in particular hammer or Drehschlagboiirkr one with carbide inserts on their End face, characterized in that apart from blade-shaped Hard metal inserts (24) and between them Distributed over the edge area of the end face, button or pin-shaped hard metal inserts (26) are provided are. Drill bit according to claim 1, characterized in that the button or. pin-shaped carbide inserts (26) are inclined outwards with respect to the drill axis. 3. Drill bit according to claim 1 or 2, characterized in that in the central region of the Boiirerstirnflache, however slightly eccentric a further hard metal pin bzv /. button (30) is provided. 4. Drill bit according to claims 1 to 3 »characterized in that two diametrically opposed, but parallel to the diameter arranged cutting inserts (24) and \ ^r ier pin-shaped or button-shaped inserts (26) are provided. r. Drill bit naci: Claims 1 to 4, characterized in that 009835/1222 ORIGINAL JMSPECTED Q 4 / f 5 5 T that branch off from the central flushing bore (12) ″ channels (36). ' 6. Drill bit according to claim 5, characterized in that the branch channels (36) open into grooves (38) extending radially on the drill end face (2p). 7. drill bit according to claim 6, characterized in that along surface lines; Channels (34) run. 8. drill bit according to claim 6, characterized in that the grooves or grooves (34) running along surface lines are arranged between two inserts (26) and communicate with the radial channels (38). 9. Drill bit according to claim 8, characterized in that the cone angle is at least that adjoining the working surface Part of the base body (10) is 10 to 16 °. 10. A drill bit according to claim 9, characterized in that the part of the base body having the end face (20) via an annular shoulder or a shoulder into a slimmer, conical part passes over. 11. A drill bit according to claim 10, characterized in that. ^. 009835/1222 ORIGINAL JNSPECTSD 1Q44551 sioli from the tapered part of the base body undercuts "or recesses (40) extend into the widened lower part having the work surface (20), which have the same slope as the tapered part and just below the cutting inserts (24) end up. 12. Drill bit according to claim 1 to 11, characterized in that the end face (20) in the area of the pin or button-shaped inserts (26) are provided with cut-offs (42). 13 · drill bit according to at least one of the preceding claims, characterized in that the cutting inserts (24) have bevels (50) at their outer ends. 009838/1222 ORIGINAL INSPECTED Lee on the back