U.S. patent application number 13/416411 was filed with the patent office on 2012-09-13 for sliding anchor.
Invention is credited to Richard Podesser, Frank Schmidt.
Application Number | 20120230774 13/416411 |
Document ID | / |
Family ID | 45655199 |
Filed Date | 2012-09-13 |
United States Patent
Application |
20120230774 |
Kind Code |
A1 |
Podesser; Richard ; et
al. |
September 13, 2012 |
SLIDING ANCHOR
Abstract
A chemical sliding anchor, in particular for use in mining, for
the firm bonding to the rock in a borehole using a fixing agent,
comprises an anchor pipe, preferably an anchor nut, anchor plate
preferably supported by the anchor nut, for lying on the rock,
involving little technical effort by effectively using a sliding
function of the sliding anchor in the case of a large change in
length of the sliding anchor on absorbing dynamic loads. An elastic
element, in particular a spring, is integrated in the sliding
anchor and an increase in length of the sliding anchor is effected
for a given sliding function with a spring deflection of the
elastic element.
Inventors: |
Podesser; Richard; (Buchloe,
DE) ; Schmidt; Frank; (Munchen, DE) |
Family ID: |
45655199 |
Appl. No.: |
13/416411 |
Filed: |
March 9, 2012 |
Current U.S.
Class: |
405/259.1 |
Current CPC
Class: |
E21D 21/0033 20130101;
E21D 21/008 20130101 |
Class at
Publication: |
405/259.1 |
International
Class: |
E21D 21/00 20060101
E21D021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2011 |
DE |
102011005361.1 |
Claims
1. Chemical sliding anchor especially for use in mining for a
firmly bonded fixing to rock in a borehole with fixation equipment,
comprising an anchor pipe; an anchor nut; an anchor plate supported
by the anchor nut for positioning on the rock, wherein an elastic
element is integrated in the sliding anchor whereby an increase in
the length of the sliding anchor is achieved by a sliding movement
on deflection of the elastic element.
2. The sliding anchor according to claim 1, wherein said elastic
element is a spring,
3. The sliding anchor according to claim 1, wherein the sliding
anchor has a sleeve and the elastic element is arranged inside the
sleeve.
4. The sliding anchor according to claim 1, wherein the sliding
anchor has a change in length of the elastic element is aligned in
the direction of a longitudinal axis of the anchor pipe.
5. The sliding anchor according to claim 1, wherein the sliding
anchor is provided with a damping element for absorbing dynamic
forces.
6. The sliding anchor according to claim 1, wherein the elastic
element is an additional component in addition to the anchor
pipe.
7. The sliding anchor according to claim 2, wherein the anchor pipe
is arranged within the sleeve, and the elastic element is arranged
between the anchor pipe and the sleeve.
8. The sliding anchor according to claim 3 wherein the elastic
element at one end lies on the sleeve bearing element connected to
the sleeve while at the other end it lies on the anchor pipe
support element connected to the anchor pipe.
9. The sliding anchor according to claim 3 wherein the sleeve is
closed in the area of the anchor pipe support element by a closure
cap.
10. The sliding anchor according to claim 4. wherein the sleeve
bearing element is designed as a plate with an opening and the
anchor pipe is arranged in the opening of the plate.
11. The sliding anchor according to claim 10, wherein the anchor
pipe bearing element is in the form of a support ring.
12. The sliding anchor according to one or more claim 10, wherein
the anchor pipe bearing element is enclosed, in particular
completely, inside a preferably cylindrical sleeve space in the
sleeve.
13. The sliding anchor according to claim 3, wherein the sleeve is
arranged in the area of a rear end of the anchor pipe in order to
position the sleeve within a borehole in the rock while the anchor
nut is directly or indirectly attached to the anchor pipe and
preferably the sleeve forms the material connection between the
fixing agent and the rock of a borehole.
14. The sliding anchor according to claim 3, wherein the sleeve is
arranged in the area of the front end the anchor pipe to position
the sleeve outside the borehole in the rock while the anchor plate
lies directly or indirectly on the sleeve or the sleeve support
member, whereby the anchor plate lies against the rock on a rock
side and lies on a sleeve side of the sleeve or sleeve bearing
element while the rock side is formed opposite the sleeve side on
the anchor plate.
15. The sliding anchor according to claim 3, wherein the sleeve is
arranged in the area of the front end of the anchor pipe to
position the sleeve inside the borehole in the rock and the sleeve
is connected to the anchor plate and/or the anchor nut.
16. The sliding anchor according to claim 1, wherein the anchor
pipe is at least partially made of metal such as steel or,
preferably fiber-reinforced plastic.
17. The sliding anchor according to claim 1, wherein the elastic
element is in the form of a coil spring, a volute spring, an
annular spring, a folding plate or an elastic plastic, such as
rubber spring.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to German Patent
Application DE 10 2011 005 361.1, filed Mar. 10, 2011, and entitled
"Gleitanker" ("Sliding Anchor"), which is hereby incorporated by
reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to a sliding
anchor.
[0003] In mining and tunneling, rock bolts are used to prevent or
slow down movement of the bedrock, or to avoid greater spalling of
the bedrock and thus ensure safe operation. Two functional
principles are known, which may also be partially combined. In the
case of mechanical systems, anchoring of the anchor means is
achieved by frictional interaction, whereby the mechanical rock
anchors also generally have an expansion sleeve. In the case of
chemical rock anchors, anchor pipes are firmly bonded to the
substrate or the bedrock using mortar or a hardening resin as a
fixing agent. The rock bolts are installed in the bedrock either
with or without preloading. Rock bolts used in mining, such as in
underground coal mining and unlike those used for tunneling, are
only used for temporary support of the rock because, in general,
the temporarily supported rock is mined in a subsequent operation
and so the rock bolts are removed from the rock.
[0004] When sliding anchors are used as rock bolts, a sliding of
the sliding anchor on an anchor plate in a longitudinal direction
is possible above a certain compressive force. In this case, an
anchor plate generally lies on the anchor nut while a female thread
engages in a male thread of a rod protrusion of an anchor pipe.
Above a given tension in the anchor pipe or a compressive force on
the anchor plate, where the rock is lying on the anchor plate, the
anchor nut like the rod protrusion may move a certain sliding
distance on the anchor pipe and thereby enable an increase in the
length of the sliding anchor. The sliding anchor thus requires a
large rod protrusion in the working space for the sliding function
outside the rock, such as in tunnels. However, this freedom of
movement and the working space in the gallery of a mine is severely
limited. Furthermore, considerable technical effort is required to
enable the sliding movement of the anchor nut on the rod
protrusion. As an alternative, the sliding function, i.e. the
change in length of the sliding anchor, may also be effected by an
elastic elongation of the anchor pipe. Because of the rigidity of
such sliding anchors, there is a risk of an unforeseen anchor
rupture and an anchor failure under dynamic loads, e.g. due to rock
bursts.
[0005] DE 29 04 778 A1 shows a monitoring device for detecting and
displaying roof movements by means of a supporting device anchored
and extending longitudinally above the roof, to whose lower end at
the roof surface is attached a sensing device that is responsive to
changes in length and displays roof movements, and where there is a
holding device that is supported on, and movable with respect to,
the supporting device for the sensing device that is suspended from
it and automatically swings down under the effect of gravity, along
with a locking device for automatic locking of a sensing device in
a highly tilted position, and a release mechanism mounted at the
lower end of the supporting device to release the locking on the
occurrence of a predetermined relative movement with respect to the
holding device.
BRIEF SUMMARY OF THE INVENTION
[0006] A chemical sliding anchor, in particular for use in mining,
for the firm bonding to the rock in a borehole using a fixing
agent, comprises an anchor pipe, preferably an anchor nut, anchor
plate preferably supported by the anchor nut, for lying on the
rock, involving little technical effort by effectively using a
sliding function of the sliding anchor in the case of a large
change in length of the sliding anchor on absorbing dynamic loads.
An elastic element, in particular a spring, is integrated in the
sliding anchor and an increase in length of the sliding anchor is
effected for a given sliding function with a spring deflection of
the elastic element.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments according to the invention are described in more
detail below with reference to the accompanying drawings. The
figures show:
[0008] FIG. 1 shows a longitudinal section of a sliding anchor in a
first embodiment in a borehole in the rock,
[0009] FIG. 2 shows a longitudinal section of the sliding anchor in
a second embodiment in a borehole in the rock, and
[0010] FIG. 3 shows a longitudinal section of the sliding anchor in
a third embodiment in the borehole in the rock.
DETAILED DESCRIPTION OF THE INVENTION
[0011] One or more embodiments of the present invention provides a
sliding anchor which, featuring low technical complexity, enables
an effective sliding function of the sliding anchor in the event of
a large longitudinal change of the sliding anchor by the absorption
of dynamic loads.
[0012] This performance is achieved using a chemical sliding
anchor, in particular for use in mining, for firm bonding to rocks
in a borehole using a fixing agent, comprising an anchor pipe,
preferably an anchor nut, and preferably an anchor plate to rest
against the rock and supported by the anchor nut, whereby an
elastic element, in particular a spring, is integrated in the
sliding anchor enabling a longitudinal movement of the sliding
anchor for a sliding function with a spring deflection, i.e. an
elastic deformation of the elastic element is effected.
[0013] The elastic element, in particular the spring, may absorb
both static and dynamic forces as a separate component
independently of the anchor pipe. Thus the static and dynamic
forces acting on the anchor pipe may be absorbed by the spring. In
particular, this enables dynamic loads to be damped and, in the
case of static forces acting on the anchor pipe, enables a
longitudinal extension of the sliding anchor due to a spring
deflection of the spring and thus the tensile forces to be absorbed
by the sliding anchor may be reduced. Thus this offers an effective
way to avoid an unexpected breakdown of the sliding anchor and, due
to the good absorption ability of dynamic loads as well, the risk
of failure under dynamic loads may be reduced considerably by using
sliding anchors, for example, under the effect of the rock bursts
or tremors. In addition, the spring deflection of the sliding
anchor is advantageously limited and thus the possible sliding path
of the sliding anchor is also limited. Thus the possible
deformation path and the possible deformation of the rock on the
sliding anchor may be limited in an advantageous manner.
[0014] In particular, the sliding anchor has a sleeve and the
elastic element is arranged inside the sleeve, and/or any change in
length of the elastic element is aligned in the direction of a
longitudinal axis of the anchor pipe and/or the sliding anchor is
provided with a damper to absorb dynamic forces and/or the elastic
element is an additional component in addition to the anchor pipe.
The damping element is used for additional absorption of dynamic
forces and may be designed, for example, as a folding plate, a
spring or an elastic plastic, such as a thermoplastic,
thermosetting or elastomeric plastic, as well as especially a
damping element with a movable piston inside a cylinder with a
fluid, such as oil or water. Such a damping element with a piston
and cylinder corresponds in its technical design and its function
to a damping element as used, for example, as a shock absorber in a
car.
[0015] In a further embodiment, the anchor pipe is arranged inside
the sleeve while the elastic element is preferably arranged between
the anchor pipe and the sleeve.
[0016] In an additional embodiment, the elastic element lies on a
sleeve bearing element connected at one end with the sleeve, while
the other end lies on an anchor pipe bearing element connected with
the anchor pipe and/or the sleeve is closed in the area of the
anchor pipe bearing element by a closure cap.
[0017] Preferably, the sleeve bearing element is designed as a
plate with an opening and the anchor pipe is arranged in the
opening of the plate. The anchor pipe is thus supported to be
axially movable in the opening of the plate in the direction of a
longitudinal axis of the anchor pipe and radially to the opening of
the plate.
[0018] In one embodiment, the anchor pipe bearing element is
designed as a support ring. The support ring may be designed to be
integral with the anchor pipe or separate and connected to the
anchor pipe as a material, shaped and/or frictionally bound
component. The support ring causes the forces absorbed by the
anchor pipe to be transmitted from the elastic element, in
particular the spring, to the anchor pipe.
[0019] It is expedient to arrange the anchor pipe bearing element
inside the preferably cylindrical sleeve space that is enclosed, in
particular completely, inside the sleeve.
[0020] In another embodiment, the sleeve is arranged in the area of
a rear end of the anchor pipe in order to position the sleeve
within a borehole in the rock while the anchor nut is directly or
indirectly attached to the anchor pipe and preferably the sleeve
forms the material connection between the fixing agent and the rock
of a borehole or the sleeve is arranged in the area of the front
end the anchor pipe to position the sleeve outside the borehole in
the rock while the anchor plate lies directly or indirectly on the
sleeve or the sleeve bearing element, whereby the anchor plate lies
against the rock on a rock side and lies on a sleeve side on the
sleeve or sleeve bearing element while the rock side is formed
opposite the sleeve side on the anchor plate or the sleeve is
arranged in the area of the front end of the anchor pipe to
position the sleeve inside the borehole in the rock and the sleeve
is connected to the anchor plate and/or the anchor nut.
[0021] In particular, the anchor pipe is at least partially,
preferably completely, made of metal such as steel or, preferably,
fiber-reinforced plastic.
[0022] In another embodiment, the spring is in the form of a coil
spring, a volute spring, an annular spring, a folding plate or an
elastic plastic, such as a rubber spring.
[0023] It is useful to have the sliding path mainly effected by a
spring deflection of the elastic element, i.e. by at least 50%, 80%
or 90%.
[0024] In an additional variant the sliding path, i.e. the increase
in length of the sliding anchor, is a function that is, for
example, directly proportional to the change in length,
particularly compression, of the elastic element, in particular
where the elastic element is coupled with a mechanism with a
component of the sliding anchor, in particular the anchor plate.
Preferably, the mechanism includes an axially-movable sleeve.
[0025] In a further embodiment, the anchor pipe has an inner space
in the form of a hollow pipe while the fixing agent is arranged
inside the anchor pipe, e.g. in a bag or a cartridge. The fixing
agent is, for example, a two-component resin with an adhesive
component and a hardening component. The adhesive and a hardening
components are first separately stored in the inner space, e.g. in
a bag or a cartridge, and then mixed prior to extrusion from the
inner space, and then the mixed resin is extruded into a space
between the anchor pipe and the rock in the borehole to make a
material connection between the anchor pipe and the rock.
[0026] Appropriately, the elastic element, especially the spring,
is integrated into the hollow pipe as the anchor pipe, whereby the
elastic element is arranged between two parts or sections of the
hollow pipe and connected to two parts or sections, whereby the
elastic element is preferably arranged outside an area with the
fixing agent.
[0027] In an additional embodiment, the sliding anchor has at least
one means, e.g. a dispensing device, to extrude the fixing agent
from the inner space enclosed by the anchor pipe into a space
between the anchor pipe and the rock in a borehole with a sliding
anchor inserted. The dispensing device, for example, comprises a
piston and a pressure is exerted on the piston by water under high
pressure, so that the piston moves within the inner space and
forces the fixing agent out. To this end, the anchor pipe has at
least one opening through which the fixing agent may be extruded.
Preferably, for this, a mixing device is provided which enables the
mixing of a fixing agent before being extruded.
[0028] A sliding anchor shown in FIG. 1 as a rock anchor 1 is a
mine anchor that is used in mining for temporary support of
tunnels. The sliding anchor 1 may absorb tensile forces, and thus
stop outer rock layers from detaching in tunnels in the mining
industry by transferring these forces into deeper layers.
Furthermore, shear forces on the rock 18 are absorbed by the
sliding anchor 1 and thus there is additional assurance with
respect to the outer layers of rock in the tunnel in the mine.
[0029] Sliding anchor 1 comprises an anchor pipe 2 made of metal
such as steel or glass fiber reinforced plastic as a solid profile
with no cavities. To secure a tunnel in a mine, a borehole 19 is
first drilled in the rock 18 in the tunnel and subsequently a
fixing agent 20 such as a resin in a cartridge or concrete is
introduced into the hole 19. Then the sliding anchor 1 is
introduced in the borehole 19 and then the fixing agent 20 is
extruded into a space 21 between the sliding anchor 1 and the rock
18.
[0030] FIG. 1 illustrates a first embodiment of the sliding anchor
1. The sliding anchor 1 is already inserted into the borehole 19 in
the rock 18 and is firmly bonded to the rock 18 with the fixing
agent 20. The anchor pipe 2 has a front end 3 in a working chamber
22 and a rear end 4 in the area of the borehole 19. At the rear end
section of the anchor pipe 2, a cylindrical sleeve 11 is coaxially
pushed onto the anchor pipe 2. Between the sleeve 11 and the anchor
pipe 2, a spring 9 in the form of a coil spring 10 serves as an
elastic element 9 made of steel that is arranged in an inner space
12 enclosed by the sleeve 11. An anchor pipe bearing element 16 in
the form of a support ring 17 is arranged at the rear end 4 of
anchor pipe 2. The support ring 17 is then connected with the
anchor pipe 2 so that it is not movable along a longitudinal axis 6
of the anchor pipe 2. A plate 15 is formed integrally with the
sleeve 11 as a sleeve bearing element 14 at a front end of the
sleeve 11. The sleeve bearing element 14 or the plate 15 has an
opening and the anchor pipe 4 is mounted axially in this opening.
Thus it is possible that in the axial direction, i.e. along the
longitudinal axis 6 of the anchor pipe 2, to move the anchor pipe 2
relative to the plate 15 and thus also to the sleeve 11. The sleeve
11 is firmly bonded by the fixing agent 20 to the rock 18. To allow
such axial movement of the anchor pipe 2 even in the area of the
anchor pipe 2 with fixing agent 20, the anchor pipe 2 is provided
with a sliding coating 5 so that effectively no forces are
transferred between the anchor pipe 2 and the fixing agent 20.
Between the coil spring 10 and the plate 15, an additional damping
element 23 is provided to absorb dynamic loads. The sleeve 11 is
closed in the area of a rear end of the sleeve 11 by a closure cap
13.
[0031] In the area of the front end 3, the anchor pipe 2 is
provided with an external thread. An anchor plate 8 and an anchor
nut 7 are displaced towards the anchor pipe 2 in the working
chamber 22, i.e. pushed out of the hole 19. Here, the anchor nut 7,
presents a non-illustrated female thread which engages with the
male thread of the anchor pipe 2. The anchor plate 8 thus lies
against the rock 18 in the area of the borehole mouth, so that it
is secured by the rock 18, whereby forces are applied by the anchor
plate 8 on the rock 18 and these are transferred as tensile forces
to the anchor pipe 2 with the anchor nut 7. The tensile forces in
the anchor pipe 2 are applied to the coil spring 10 via the support
ring 17 and from the coil spring 10 to the damping element 23 and
from the damping element 23 to the plate 15 or the sleeve bearing
element 14. The axial forces acting on the sleeve member 14 in the
direction of the longitudinal axis 6 are transferred to the sleeve
11 and from the sleeve 11 to the rock 18 through the fixing agent
20. This enables the outer layers of rock 18 to be held by the
sliding anchor 1 and the transfer of the forces required to hold
the outer layers of rock 18 to deeper rock layers 18 in the area of
the fixing agent 20. In addition to another component, for example
anchor pipe 2, of the sliding anchor 1, spring 9, as an elastic
element 9, is elastically deformable according to Hooke's law where
F=-c.times.s, where c is the spring constant of the spring 9 and s
the spring deflection in the form of elongation or compression of
the spring 9. The force F thus corresponds to the tensile force
acting on anchor pipe 2 and which acts as a compressive force on
the spring 9. The sliding anchor 1 thus has a sliding function and,
in the case of deformations of the outer layers of rock 18, it is
possible to avoid a breakdown or a failure of the sliding anchor 1
due to an increase in length of the sliding anchor 1 because of a
change in length or a compression of the spring 9, even in the case
of larger separations or deformation of the rock 18 in the area of
the anchor plate 8. The spring 9 may thus also absorb or dampen
dynamic loading.
[0032] In FIG. 2, a second embodiment of the sliding anchor 1 is
shown. In what follows, only the essential differences with respect
to the first embodiment shown in FIG. 1 are described. The sleeve
11 is arranged outside the fixing agent 20 in the borehole 19 in
the rock 18 and the transfer to the rock 18 of tensile forces
absorbed by the anchor pipe 2 is effected by the direct contact of
the fixing agent 20 with the anchor pipe 2. The anchor nut 7 is not
connected to the anchor pipe 2, but the sleeve 11 has a
non-illustrated male thread which engages in a non-illustrated
female thread of the anchor nut 7. This allows transfer of the
forces acting on the anchor plate 8 to be transferred as tensile
forces to the anchor nut 7 and from the anchor nut 7 to the sleeve
11. These tensile forces are transferred from the sleeve 11 to the
sleeve bearing element 15 and from this to the screw spring 10. The
coil spring 10 transfers these tensile forces as compressive forces
to the damping element 23 and the second support ring 17 as tensile
forces in the anchor pipe 2. Upon movement of the outer layers of
rock 18 or the anchor plate 8 to the right as shown in FIG. 2, the
sleeve 11 is also moved to the right. The anchor pipe 2 remains
unchanged in its axial position and there is thus a relative
movement between the sleeve 11 and the fixed anchor pipe 2.
[0033] FIG. 3 shows a third embodiment of the sliding anchor 1. In
what follows, only the differences with respect to the first
embodiment shown in FIG. 1 are described. The sleeve 11 is arranged
outside the borehole 19 in the working chamber 22. The transfer of
the tension forces acting on the anchor pipe 2 to the rock 18 is
effected through direct contact between the anchor pipe 2 and the
fixing agent 20. The sliding anchor 1 has no anchor nut 7 and the
plate 15 rests on the anchor plate 8 as a sleeve bearing element
14. Upon movement of the outer layers of rock or the anchor plate 8
to the right as shown in FIG. 3, then the anchor plate 8 as well as
the sleeve 11 move to the right also. The position of the anchor
pipe 2 remains unchanged with respect to deeper, fixed rock layers
due to the fixing with the fixing agent 20, so that any movement of
the anchor plate 8 to the right as shown in FIG. 3 compresses the
spring 9 (length reduction) i.e. it has a smaller deflection in the
direction of the longitudinal axis 6 because the stationary anchor
pipe 2 is connected at the front end 3 of the anchor pipe 2 of the
support ring 17 and thus the damping element 23, and thus the
spring 9, is compressed.
[0034] In addition to the anchor pipe 2 and the spring 9, the
sleeve 11, the sleeve bearing element 14 and the anchor pipe
bearing element 16 are also made of metal such as steel.
[0035] Overall, there are significant advantages connected with the
sliding anchor 1 according to the invention. The spring 9 built
into the sliding anchor 1 in the form of an elastic element 9 may
accept large deformations or changes in length thereby effecting a
change in length or a sliding of the sliding anchor 1. Thus spring
9 may also absorb dynamic loads well in addition to static loads.
The risk of a failure of the sliding anchor 1 may be reduced
significantly, while the use of springs 9 with different spring
constants in the presence of an otherwise identical sliding of the
sliding anchor 1 enables the sliding anchor 1 also to be used in a
variety of applications and with different types of rocks 18.
[0036] While particular elements, embodiments, and applications of
the present invention have been shown and described, it is
understood that the invention is not limited thereto because
modifications may be made by those skilled in the art, particularly
in light of the foregoing teaching. It is therefore contemplated by
the appended claims to cover such modifications and incorporate
those features which come within the spirit and scope of the
invention.
* * * * *