U.S. patent application number 13/095276 was filed with the patent office on 2011-11-03 for drilling tool.
This patent application is currently assigned to Hilti Aktiengesellschaft. Invention is credited to Thomas Hofbrucker, Oliver OHLENDORF.
Application Number | 20110266015 13/095276 |
Document ID | / |
Family ID | 44278640 |
Filed Date | 2011-11-03 |
United States Patent
Application |
20110266015 |
Kind Code |
A1 |
OHLENDORF; Oliver ; et
al. |
November 3, 2011 |
DRILLING TOOL
Abstract
A drilling tool is disclosed. The drilling tool has a shaft and
a pot-shaped base body. Chisel cutters are inserted into the
annular front surface of the base body which is open on a drilling
side. At least one suction opening is provided offset radially from
an axis of the hammer core bit in the base of the base body facing
away from the drilling side. The drilling dust can be suctioned out
of the base body through the suction openings.
Inventors: |
OHLENDORF; Oliver;
(Landsberg, DE) ; Hofbrucker; Thomas; (Mammendorf,
DE) |
Assignee: |
Hilti Aktiengesellschaft
Schaan
LI
|
Family ID: |
44278640 |
Appl. No.: |
13/095276 |
Filed: |
April 27, 2011 |
Current U.S.
Class: |
173/198 ;
408/56 |
Current CPC
Class: |
B25F 3/00 20130101; B23Q
11/0046 20130101; Y10T 16/4713 20150115; Y10T 408/44 20150115 |
Class at
Publication: |
173/198 ;
408/56 |
International
Class: |
B25D 17/14 20060101
B25D017/14; B23B 47/34 20060101 B23B047/34 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 2010 |
DE |
10 2010 028 302.9 |
Claims
1. A drilling tool, comprising: a shaft disposed on an axis of the
drilling tool; a base body with an annular front surface and a
base; and a suction opening in the base that is offset radially
from the axis.
2. The drilling tool according to claim 1, wherein the suction
opening runs in a drilling direction toward the axis.
3. The drilling tool according to claim 1, wherein the shaft abuts
the base with a conically widening foot and wherein the suction
opening runs through the foot.
4. The drilling tool according to claim 1, further comprising a
plurality of chisel cutters inserted into the annular front face
and wherein the plurality of chisel cutters are made of hard
metal.
5. The drilling tool according to claim 4, wherein the plurality of
chisel cutters have cutting surfaces, wherein the cutting surfaces
of a group of the plurality of chisel cutters are oriented radially
to the annular front surface, and wherein the cutting surfaces of
another group of the plurality of chisel cutters are oriented
tangentially to the annular front surface.
6. The drilling tool according to claim 1, further comprising a
centering drill arranged on the axis within the base body.
7. The drilling tool according to claim 1, wherein the suction
opening is arranged at a distance from the axis that is between 30%
and 70% of a radius of the base body.
8. The drilling tool according to claim 1, wherein a maximum of
five suction openings are provided.
9. The drilling tool according to claim 1, wherein a suction tube
is arranged coaxially to the shaft and abuts the base.
10. The drilling tool according to claim 9, wherein an outside
diameter of the suction tube is less than an outside diameter of
the base body.
11. The drilling tool according to claim 9, wherein the suction
tube has an elastic bellows and wherein an annular end of the
elastic bellows abuts the base at least in sections.
12. The drilling tool according to claim 9, wherein the suction
tube has a plurality of first sections and a plurality of second
sections circumferentially on an annular front surface, wherein the
plurality of first sections projects a different distance from the
annular front surface than the plurality of second sections.
13. The drilling tool according to claim 12, wherein the plurality
of first sections are arranged over 10% to 20% of the annular front
surface.
14. The drilling tool according to claim 9, wherein ribs projecting
toward the axis are arranged within the suction tube.
15. The drilling tool according to claim 9, wherein a front end of
the suction tube defines an opening in the suction tube.
16. The drilling tool according to claim 15, wherein a front
surface of the suction tube is flat and wherein the front surface
abuts the base.
Description
[0001] This application claims the priority of German Patent
Document No. 10 2010 028 302.9, filed Apr. 28, 2010, the disclosure
of which is expressly incorporated by reference herein.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] The present invention relates to a drilling tool for
percussive or rotary percussive processing of stone, concrete or
other rock-like materials of the building and construction
industry.
[0003] The bore-chiseling drilling tool according to the invention
has a shaft and a pot-shaped base body. Chisel cutters are inserted
into an annular front surface of the base body that is open on a
drilling side. At least one suction opening is provided offset
radially from an axis of the hammer core bit in the base of the
base body facing away from the drilling side. The drilling dust can
be suctioned out of the base body through the suction openings.
[0004] At least one suction opening can run in the drilling
direction toward an axis of the base body, i.e., run diagonally
toward the axis. The shaft may abut the base with a conically
widening foot and the suction opening may run through the foot.
[0005] The chisel cutters may be made of hard metal. In one
embodiment, the cutting surfaces of a group of chisel cutters are
oriented radially and the cutting surfaces of another group of the
chisel cutters are oriented tangentially to the front surface. The
two groups of chisel cutters are oriented differently to the
circumference each by 90 degrees. The forces occurring during
chiseling and the rotational offsetting of the chisel cutters are
introduced to some extent in a different manner to the base body
and its base because of the two groups. Based on continuous load
tests of core bits with chisel cutters arranged in this manner, it
is assumed that more efficient removal and a lower mechanical load
of the base can be achieved hereby.
[0006] A rod-shaped centering drill may be arranged on the axis
within the pot-shaped base body.
[0007] One embodiment provides that the suction openings are
arranged at a distance from the axis that is between 30% and 70% of
the radius of the base body. A maximum of five suction openings may
be provided; with a greater number, the base becomes soft and can
dampen shocks.
[0008] One embodiment provides that a suction tube be arranged
coaxially to the shaft and a suction opening abuts the base in an
enclosing manner at least in sections. An outside diameter of the
suction tube can be less than an outside diameter of the base body.
The suction tube may have an elastic bellows or telescoping sleeve,
whose annular end touches the base at least in sections. Lateral
openings may be provided in the bellows or the telescoping sleeve
through which air may be sucked in. The suction tube may have first
sections and second sections circumferentially on its annular front
surface pointing in the drilling direction, where the first
sections project in the drilling direction by a maximum of 3 mm as
compared to the second sections. The first sections or elevations
space the suction tube apart from the base in such a way that slots
are produced between the second sections and the annular front
surface. A percentage of the first sections on the circumference of
the front surface is, for example, between 10% and 20%.
[0009] One embodiment provides that ribs projecting toward the axis
are arranged within the suction tube, whose facets pointing toward
the axis touch the shaft.
[0010] The following description explains the invention on the
basis of exemplary embodiments and figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a longitudinal section of a drilling tool;
[0012] FIG. 2 is a top view of the drilling tool;
[0013] FIG. 3 is a detailed view of an embodiment of a front end of
a suction tube of the drilling tool; and
[0014] FIG. 4 is a detailed view of an alternative embodiment of a
front end of a suction tube of the drilling tool.
DETAILED DESCRIPTION OF THE DRAWINGS
[0015] Unless otherwise indicated, the same or functionally
equivalent elements are indicated by the same reference numbers in
the figures.
[0016] FIG. 1 shows a longitudinal section of a hammer core bit 1
and FIG. 2 shows a top view. The hammer core bit 1 has several
chisel cutters 2, which are inserted into an annular front surface
3 of a cylindrical base body 4. The chisel cutters 2 are preferably
made of hard metal, e.g., of sintered composition material with
tungsten carbide, and are suitable for a chiseling and cutting
removal of stone, concrete or mineral construction materials. The
chisel cutters 2 project beyond the front surface 3 in the drilling
direction 5. The chisel cutters 2 may have one or two cutting
surfaces 6 inclined to the front surface 3 of the base body 4. In a
preferred embodiment, the chisel cutters 2 are inserted into the
front surface 3 in different orientations. Whereas, in the case of
a first group of the chisel cutters 2, the cutting surfaces 6 run
in a radial direction, in the case of a second group, the cutting
surfaces 6 are aligned tangentially to the annular front surface 3.
The different alignment has proven to be advantageous in terms of
the distribution of shock waves in percussive drilling. A radial
dimension of the chisel cutters 2 may be greater than a thickness
of the front surface 3, i.e., the difference between an outer and
an inner radius. In particular, the chisel cutters 2 may project
radially outwardly beyond the front surface 3 in order to define a
drilling diameter.
[0017] A wall 9 radially limiting the cylindrical base body 4 is
preferably completely closed. On a front surface facing away from
the drilling side, a base 10 closes the base body 4 perpendicular
to its axis 11.
[0018] A rod-shaped shaft 12 abuts the base 10 of the base body 4
in the extension of the axis 11. The shaft 12 and the base body 4
may be manufactured of one blank, i.e., without a joining seam or
other connecting point. The shaft 12 may have a conically widening
foot 13, which is connected to the base 10. An end section facing
away from the base body 4 is configured to be an insertion end 15
with open and closed grooves for a rotary percussive power
tool.
[0019] A blind hole 16 that runs coaxially to the axis 11 is
introduced through the base 10 into the shaft 12. The blind hole 16
is used to accommodate a centering drill 17. The blind hole 16 may
be conically tapering against the drilling direction 5 in such a
way that the inserted centering drill 17 clamps in. A bore 18
crossing the blind hole 16 runs through the shaft 12. A user can
push the centering drill out of the blind hole 16 by driving a pin
into the bore. The centering drill 17 arranged on the axis 11
projects beyond the front surface 3 in the drilling direction
5.
[0020] Suction openings 19 are introduced in the base 10, which
make it possible to suction from an interior space 20 of the base
body 4. The suction openings 19 can weaken the mechanical stability
of the hammer core bit 1, in particular with respect to the shocks
initiated regularly in the base body 4 via the shaft 12 by the
percussive hand-held power tool. The suction openings 19 are
arranged at a distance 21 of between 30% and 70% of the outer
radius of the base body 4 to the axis 11. In one embodiment, the
suction openings 19 run inclined or diagonally toward the axis 11,
wherein they run in the drilling direction 5 toward the axis 11.
The suction openings 19 can preferably run through the foot 13 of
the shaft 12. A diameter of the suction openings 19 can be, for
example, in the range of 3 mm to 10 mm. A maximum of five suction
openings 19 may be provided. The suction openings 19 may also be
configured as elongated holes.
[0021] A suction tube 22 is put over the shaft 12 of the hammer
core bit 1. A front end 23 of the suction tube 22 abuts the base 10
of the base body 4 on the outside and covers the suction openings
19. The front end is preferably formed by an elastic bellows 24.
The elastic bellows 24 is used for compensation based on the
tolerances of shafts 12 of different lengths. An outside diameter
25 of the bellows 24 is less than outside diameter 26 of the base
body 4. An inside diameter of the bellows 24 is greater than the
distance of the suction openings 19 to the axis 11 at least in the
region of the contact surface with the base 10. Instead of a
bellows 24, an axially displaceable sleeve may be arranged on the
suction tube 22. The system of the suction tube 22 and sleeve is
therefore telescoping and adaptable in terms of length to the
length of the hammer core bit 1.
[0022] An annular front surface 28 of the front end 23 abuts the
base 10 preferably only in sections and not as a closed ring (see
detailed view in FIG. 3). The front surface 28 has several knobs 29
arranged in a distributed manner along its circumference, which
project in the drilling direction 5. Several slots 30 form between
the suction tube 22 and the base 10, through which air can be
suctioned into the suction tube 22. The additional air flow can
promote the air flow through the suction openings 19 or suction air
along an outer side of the base body 4. The bearing surface of the
front surface 28 on the base 10 amounts to only approx. 10% to 20%
of the front surface 28 because of the projecting knobs 29. The
slots 30 form between the non-supported areas of the front surface
28 and the base 10 of the hammer core bit 1. The slots 30 have a
limited height (dimension along the axis 11), e.g., between 1 mm
and 3 mm, and the knobs 29 are configured to be correspondingly
high. In the case of a greater height of the knobs 29, the air flow
through the suction openings 19 decreases noticeably and the
cleaning capacity diminishes.
[0023] In another embodiment (FIG. 4), openings 30' are provided
near the front surface 28'. The openings 30' have a cross-sectional
area of 5 to 20 mm.sup.2 for example. The openings 30' may be
provided in addition to or as an alternative to the slots 30. In
the depicted embodiment, the front surface 28' is flat and can abut
the base 10 completely.
[0024] The preferably tubular suction tube 22 has an inside
diameter which is greater than the shaft 12 of the hammer core bit
1 such that dust can be suctioned off between the suction tube 22
and the shaft 12. Ribs 31 projecting radially inwardly toward the
axis 11 are provided to stabilize the suction tube 22. The six ribs
31 for example are arranged in different angular positions around
the axis 11 and at the same height along the axis 11. The ribs 31
are preferably arranged equidistant around the axis 11, i.e., with
six ribs 31, 60 degrees from one another respectively. The distance
of the ribs 31 to the front surface 28 may be, for example, between
4 cm and 10 cm. A distance of the facets 32 pointing toward the
axis 11 corresponds preferably to the radius of a standard shaft
12, e.g., 1 cm to 2 cm. The long suction tube 22, e.g., longer than
20 cm, can be supported laterally on the shaft 12.
[0025] The suction tube 22 is connected to a sleeve-shaped holder
33, which can be put over a tool receptacle of the power tool. The
holder 33 is arranged in the axial extension to the suction tube
22. The section put over the tool receptacle can have a lateral
window 37, though which the tool receptacle can be actuated.
[0026] The holder 33 may be fastened to a housing of the power tool
with a clamping ring 34. The clamping ring 34 may be an integral
part of a lateral hand grip 35. A rotation of the lateral hand grip
35 around its longitudinal axis actuates a pre-stressing mechanism
of the clamping ring 34. In the depicted example, a snail pulls a
section of the clamping ring 34 away from the axis 11 toward the
lateral hand grip, thereby shortening the circumference of the
clamping ring 34 and clamping the clamping ring 34 on the power
tool. The holder 33 may have a contact area 36 with a cylindrical
outer contour for applying the clamping ring 34. The contact area
36 may include an elastic plastic component.
[0027] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *