U.S. patent application number 12/152588 was filed with the patent office on 2008-11-20 for self-drilling rock anchor.
This patent application is currently assigned to Hilti Aktiengesellschaft. Invention is credited to Michael Bayerl, Kay Heemann, Wolfgang Ludwig.
Application Number | 20080286054 12/152588 |
Document ID | / |
Family ID | 39645432 |
Filed Date | 2008-11-20 |
United States Patent
Application |
20080286054 |
Kind Code |
A1 |
Bayerl; Michael ; et
al. |
November 20, 2008 |
Self-drilling rock anchor
Abstract
A self-drilling rock anchor includes a drilling head (16; 46)
provided at one end (13) of the receiving body (12), an inner tube
(21) for receiving a pressurable-out hardenable mass (26) and
provided in the receiving body (12) and having an outlet opening
(22) spaced from the drilling head (16; 46), and a mixing member
(31; 61) displaceably supported in the inner tube (21), with the
drilling head (16; 46) having a receptacle (18; 48) adjacent to the
mixing member (31; 61) for receiving a free end (32; 62) of the
mixing member (21; 61) and a through-opening (17) for the
hardenable mass (26), and the receptacle (18; 48) of the drilling
head (16; 46) having a centering section (20; 50) that cooperates
with a counter-centering section (33; 63) provided at the free end
(32; 62) of the mixing member (31; 61) adjacent to the drilling
head (16; 46).
Inventors: |
Bayerl; Michael; (Tuerkheim,
DE) ; Ludwig; Wolfgang; (Zaisertshofen, DE) ;
Heemann; Kay; (Kaufering, DE) |
Correspondence
Address: |
ABELMAN, FRAYNE & SCHWAB
666 THIRD AVENUE, 10TH FLOOR
NEW YORK
NY
10017
US
|
Assignee: |
Hilti Aktiengesellschaft
|
Family ID: |
39645432 |
Appl. No.: |
12/152588 |
Filed: |
May 14, 2008 |
Current U.S.
Class: |
405/259.5 |
Current CPC
Class: |
E21D 21/0053 20160101;
E21D 21/0033 20130101; E21D 20/021 20130101 |
Class at
Publication: |
405/259.5 |
International
Class: |
E21D 20/00 20060101
E21D020/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 2007 |
DE |
10 2007 000 277.9 |
Claims
1. A self-drilling rock anchor (11; 41), comprising: a hollow
cylindrical receiving body (12); a drilling head (16; 46) provided
at one end (13) of the receiving body (12); an inner tube (21) for
receiving a pressurable-out hardenable mass (26) and provided in
the receiving body (12) and having an outlet opening (22) spaced
from the drilling head (16; 46); a mixing member (31; 61)
displaceably supported in the inner tube (21), the drilling head
(16; 46) having a receptacle (18; 48) adjacent to the mixing member
(31; 61) for receiving a free end (32; 62) of the mixing member
(21; 61) and a through-opening (17) for the hardenable mass (26),
and the receptacle (18; 48) of the drilling head (16; 46) having a
centering section (20; 50) that cooperates with a counter-centering
section (33; 63) provided at the free end (32; 62) of the mixing
member (31; 61) adjacent to the drilling head (16; 46).
2. A rock anchor according to claim 1, wherein the centering
section (20) of the receptacle (18) of the drilling head (16) has a
funnel shape and tapers toward the free end of the drilling head
(16).
3. A rock anchor according to claim 1, wherein a wall section of
the centering section (50) that surrounds the receptacle (48) of
the drilling head (46) is formed concave.
4. A rock anchor according to claim 1, wherein a wall section of
the counter-centering section (63) that surrounds the end region of
the free end of the mixing member (61) is formed convex.
5. A rock anchor according to claim 1, wherein the centering
section (20; 50) of the receptacle (18; 48) of the drilling head
(16; 46) has a diameter (D1; D2) larger than a diameter (d1, d2) of
the counter-centering section (33; 63) of the free end (32; 62) of
the mixing member (31; 61).
6. A rock anchor according to claim 1, wherein the
counter-centering section (63) is formed of several centering
elements (64) formed at the free end (62) of the mixing member
(61).
7. A rock anchor according to claim 6, wherein the centering
elements (64) are arranged rotationally symmetrically with respect
to a longitudinal axis (23) of the inner tube (21).
8. A rock anchor according to claim 1, further comprising a stop
(19; 49) for the mixing member (31; 61) provide din the receptacle
(18; 48) of the drilling head (16; 46).
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a self-drilling rock anchor
including a hollow cylindrical receiving body, a drilling head
provided at one end of the receiving body, an inner tube for
receiving a pressurable-out hardenable mass and provided in the
receiving body and having an outlet opening spaced from the
drilling head, a mixing member displaceably supported in the inlet
tube, with the drilling head having a receptacle adjacent to the
mixing member for receiving a free end of the mixing member and a
through-opening for the hardenable mass.
[0003] 2. Description of the Prior Art
[0004] Rock anchors are attachment elements which are used for
stabilization of walls of hollow spaces such as tunnels, galleries,
and the like and, in particular, for connecting rock regions
adjacent to a wall with each other. In many cases, the regions
which are located immediately adjacent to the wall and mechanical
characteristics of which, in particular the load-carrying capacity,
are reduced as a result of formation of hollow spaces, are
connected to more remote, undamaged regions. The wall, in this
regard, means the ceiling and side walls of a hollow space and also
its bottom.
[0005] German Publication DE 103 01 968 A1 discloses a
self-drilling rock anchor provided at the working tool side with a
pressable-out mortar mass. The rock anchor is drilled in a
constructional component. In the intermediate space between the
inner tube and the receiving member and in the free space between
the outlet opening of the inner space and the drilling head, at a
dry drilling process, particles, which are commutated by the
drilling head, so-called drillings, are aspirated. Alternatively,
at a wet drilling process, rinsing water is fed to the drilling
head through the intermediate space and the free space. In order to
provide a sufficient intermediate space, spacers are provided on
the inner tube. The spacers are separate elements or are formed
during manufacturing of the inner tube. Upon reaching a desired
setting depth, the mortar mass, which is located in the inner tube,
e.g., is packed in a film bag, is squeezed out under pressure, with
a mixing element which is located in front of the pressable-out
mass, being displaceable in a receptacle of the drilling head. The
squeezable-out mortar mass, e.g., a multicomponent mortar mass,
upon further application of pressure, is mixed in the mixing
element and is squeezed through the through-opening of the drilling
head into the space that surrounds the rock anchor.
[0006] Because of the initially displaced mixing element, no
hardenable mass penetrates in the intermediate space between the
receiving member and the inner tube. In this way, the need in an
expensive hardenable mass is limited to the amount necessary to
fill the space between the outer body and the bore wall. After
hardening of the mortar mass, the rock anchor is chemically
anchored in the constructional component.
[0007] Dependent on the type of the constructional component, a
plurality of rock anchors must be used for stabilization of walls
of hollow spaces. Therefore, there is further a need, with such,
rock anchors, to reduce their manufacturing costs.
[0008] Accordingly, an object of the present invention is to
provide a rock anchor that can be economically produced in
comparison with the known rock anchors.
[0009] Another object of the present invention is to provide a rock
anchor that would insure pressing out of the pressable-out of the
pressable-out mass into the space that surrounds the receiving
member, almost without any loss of the hardenable mass.
SUMMARY OF THE INVENTION
[0010] These and other objects of the present invention, which will
become apparent hereinafter, are achieved by providing a rock
anchor of the type discussed above in which the receptacle of the
drilling head has a centering section that cooperates with a
counter-centering section provided at the free end of the mixing
member adjacent to the drilling head. In this way, the free end of
the mixing member, which is located adjacent to the drilling head,
as a result of the press-out process, upon being displaced, is
automatically received in the drilling head receptacle. This takes
place without use of a separate spacer or an additional guide
member arranged in the receiving tube such as, e.g., a ramp. When
the free end of the mixing member impacts an edge of the drilling
head adjacent thereto, the mixing member, as a result of the shape
of the free end thereof, upon continuation of the press-out
process, is deflected in the receptacle of the drilling head. As
soon as the free end of the mixing member occupies a proper
position in the centering section of the receptacle of the drilling
head, the mixed hardenable mass can flow through the
through-opening in the drilling head and fill the space that
surrounds the receiving body.
[0011] Advantageously, the mixing member is formed of a plastic
material and has, in particular, in the region of the
counter-centering section of the free end of the mixing member,
elastic deformation characteristics. Advantageously, the free end
of the mixing member is provided, in the region of the
counter-centering section, with slots extending parallel to the
longitudinal axis of the inner tube. The slots advantageously
insure elastic deformation characteristics of the counter-centering
section upon joint displacement with the centering section of the
receptacle of the drilling head.
[0012] During a drilling process, the inner tube, together with the
pressable-out mass, can wobble, so that an adequate intermediate
space between the inner tube and the receiving body for aspirating
drillings or drilling dust or for feeding of rinsing water to the
drilling head is insured.
[0013] The manufacturing costs of the inventive rock anchor in
comparison with the known rock anchor are reduced, which is an
important advantage of such a mass-produced element. Despite this,
a perfect use of the self-drilling rock anchor is insured.
[0014] Advantageously, the centering section of the receptacle of
the drilling head has a funnel shape and tapers toward the free end
of the drilling head. This shape of the centering section
facilitates joint displacement with the free conical end of the
mixing member tapering in a direction of the drilling head.
[0015] Advantageously, a wall section of the centering section that
surrounds the receptacle of the drilling head is formed concave.
Thereby, during the displacement of the mixing member, an
advantageous deflection of the free end of the mixing member in the
receptacle of the drilling head is insured. In this connection, the
term "concave" relates to the shape of the corresponding wall
section. According to an advantageous embodiment, the wall section
that surrounds the receiving space of the drilling head receptacle,
forms a partially spherical receptacle.
[0016] Advantageously, a wall section of the counter-centering
section that surrounds the end region of the free end of the mixing
member is formed convex. Thereby, upon displacement of the mixing
member, an advantageous deflection of the free end of the mixing
member in the drilling head receptacle is insured. In this
connection, the term "convex" relates to the shape of the
corresponding wall section. According to an advantageous embodiment
the wall section that surrounds the end region of the free end of
the mixing member, forms a crowned or spherical shape of the free
end of the mixing member.
[0017] Advantageously, the centering section of the receptacle of
the drilling head has a diameter larger than a diameter of the
counter-centering section of the free end of the mixing member.
This insures that the free end of the mixing member can be received
in the receptacle of the drilling head.
[0018] Advantageously, the counter-centering section is formed of
several centering elements formed at the free end of the mixing
member. The plurality of centering elements provide for deflection
of the free end of the mixing member in the receptacle of the
drilling head. It is particularly advantageous when the centering
elements are arranged rotationally symmetrically with respect to a
longitudinal axis of the inner tube, e.g., along a
double-or-multiple rotational axis. Thereby, the free end of the
mixing element can be deflected in the drilling head receptacle in
each position of the inner tube.
[0019] Preferably, a stop for the mixing member is provided in the
receptacle of the drilling head, which limits the displacement of
the mixing member. The stop is formed, e.g., as a circumferential
rim provided in the receptacle of the drilling head in the
direction of the free end of the drilling head adjacent to the
centering section. The stop would limit the displacement of the
mixing member during the press-out process. This insures that the
end region of the free end of the mixing member is not deformed,
during its displacement, to an extent that the discharge of the
mixed, pressed-out mass is restricted.
[0020] The novel features of the present invention, which are
considered as characteristic for the invention, are set forth in
the appended claims. The invention itself, however, both as to its
construction and its mode of operation, together with additional
advantages and objects thereof, will be best understood from the
following detailed description of preferred embodiments, when read
with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The drawings show:
[0022] FIG. 1 A longitudinal cross-sectional view of a first
embodiment of a rock anchor according to the present invention;
[0023] FIG. 2 a longitudinal cross-sectional view of a front
portion of a second embodiment of the rock anchor according to the
present invention; and
[0024] FIG. 3 a view at the free end of the mixing member of the
rock anchor shown in FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] A self-drilling rock anchor 11, which is shown in FIG. 1,
has a hollow cylindrical receiving body 12, a drilling head 16
provided at a first, facing in the setting direction S, end 13 of
the receiving body 12, and rotation application means 15, e.g., in
form of a polygon connectable with a rotary drilling tool, and
which is provided at an opposite, second end 14 of the receiving
body 12. The drilling head 16 has a through-opening 17 and a
receptacle 18 with a funnel-shaped centering section 20 tapering
toward the free end of the drilling head 16.
[0026] In the receiving body 12, and inner tube 21 is arranged in
which a pressable-out and hardenable mass 26, which is packed in a
foil bag, is arranged. The inner tube 21 has an outlet opening 22
spaced from the drilling head 16. In the inner tube 21, between the
hardenable mass 26 and the drilling head 16, there is provided a
displaceably supported mixing member 31 in an end region of which
at the free end 32 of the mixing member 31, there is provided a
counter-centering section 33 that cooperates with the centering
section 20 of the receptacle 18 of the drilling head 16.
[0027] A wall section of the centering section 20 of the receptacle
18 of the drilling head 16, which is adjacent to the mixing member
31, is formed concave. In the receptacle 18 of the drilling head
16, there is provided a stop 19 for the mixing member 31. A wall
section of the counter-centering section 33, which surrounds the
free end 32 of the mixing member 31, is formed convex. The diameter
D1 of the central section 20 of the receptacle 18 of the drilling
head 16 is larger than the diameter d1 of the counter-centering
section 33 of the end region of the free end 32 of the mixing
member 31.
[0028] Upon reaching a desired bore depth, the pressable-out mass
26 is ejected under pressure. At that, firstly the mixing member 31
is displaced in the direction of the drilling head 16 until the
free end 32 of the mixing member 31 lies in the receptacle 18 of
the drilling head 16.
[0029] Upon application of pressure further to the pressable-out
mass 26, it is ejected through the opening 17 in the drilling head
16 and out of the rock anchor 11.
[0030] A self-drilling rock anchor 41, which is shown partially in
FIGS. 2-3, is formed identically to the rock anchor 11 up to the
shape of the centering section 50 of the receptacle 48 of the
drilling head 46 and the counter-centering section 63 of the free
end 62 of the mixing member 61, and identical parts are designated
with the same reference numerals.
[0031] The wall sections that surround the centering section 50 are
formed concave and have a diameter D2. At the free end 62 of the
mixing member 61, there are provided several centering elements 64
which are arranged rotationally symmetrically with respect to a
longitudinal axis 23 of the inner tube 21. The free ends of the
centering elements 64 are adjacent to each other. The wall sections
which surround the counter-entering section 63 and which correspond
to the radially outer surfaces of the centering elements 64, form a
convex or crowned shape of the end region of the free end 62 of the
mixing member 61. The diameter d2 of the counter-centering section
63 is smaller than the diameter D2 of the centering section 50.
[0032] Though the present invention was shown and described with
references to the preferred embodiments, such are merely
illustrative of the present invention and are not to be construed
as a limitation thereof and various modifications of the present
invention will be apparent to those skilled in the not intended
that the present invention be limited to the disclosed embodiments
or details thereof, and the present invention includes all
variations and/or alternative embodiments within the spirit and
scope of the present invention as defined by the appended
claims.
* * * * *