U.S. patent number RE30,256 [Application Number 05/857,048] was granted by the patent office on 1980-04-08 for friction rock stabilizers.
This patent grant is currently assigned to Wendy 0. Carter, Deborah L. Castle, Amu J. Sansotta, Edna M. Scott, trustee for Polly Sue Scott and James Mathew Scott. Invention is credited to James J. Scott.
United States Patent |
RE30,256 |
Scott |
April 8, 1980 |
**Please see images for:
( Certificate of Correction ) ** |
Friction rock stabilizers
Abstract
Friction rock stabilizers such as for example roof anchors,
comprising a erally annular body which from end-to-end has a slot
through its thickness and is circumferentially compressible for
installation into a bore of diameter substantially smaller than the
normal outer diameter of the body whereby, after such installation,
the resilience of the body causes the body outer periphery to
anchor by frictional engagement with the surrounding wall of the
bore. Also, an anchoring method employing a stabilizer of this
type.
Inventors: |
Scott; James J. (Rolla,
MO) |
Assignee: |
Castle; Deborah L. (Milford,
NJ)
Carter; Wendy 0. (Viburnum, MO)
Sansotta; Amu J. (Fairfax, VA)
Scott, trustee for Polly Sue Scott and James Mathew Scott; Edna
M. (Rolla, MO)
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Family
ID: |
26987523 |
Appl.
No.: |
05/857,048 |
Filed: |
December 2, 1977 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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430695 |
Jan 4, 1974 |
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330954 |
Feb 9, 1973 |
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Reissue of: |
520310 |
Nov 4, 1974 |
03922867 |
Dec 2, 1975 |
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Current U.S.
Class: |
405/259.3;
411/355 |
Current CPC
Class: |
E21D
21/004 (20130101) |
Current International
Class: |
E21D
21/00 (20060101); E21D 021/00 (); E21D
020/00 () |
Field of
Search: |
;61/45B,63,53.68,45R
;85/8.3,84,80,85,32.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1443392 |
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May 1966 |
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FR |
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825003 |
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Dec 1959 |
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GB |
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1028664 |
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May 1966 |
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GB |
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Primary Examiner: Taylor; Dennis L.
Attorney, Agent or Firm: Murphy; Bernard J.
Parent Case Text
This is a Continuation-in-Part of my U.S. Pat. Application Ser. No.
430,695 filed Jan. 4, 1974, .Iadd.now abandoned .Iaddend.which is a
Continuation-in-Part of my U.S. Pat. Application Ser. No. 330,954
filed Feb. 9, 1973, now abandoned.
Claims
I claim:
1. A friction stabilizer for insertion in a bore in a structure
such as a roof or side wall of a mine shaft or other underground
opening for anchoring the structure, said stabilizer comprising a
generally annular body from end-to-end having a slot through its
thickness, said body including edge portions extending along
opposite sides of said slot and relatively arranged to permit
substantial circumferential compression of said body, said body
being of outer diameter predetermined to be substantially larger
than the diameter of the bore in which it is to be inserted such
that insertion of said body in such bore causes substantial
circumferential compression of said body, said body being
dimensioned to be plastically deformed during its insertion in such
bore, the stabilizer being free of structure precluding said
substantial compression and plastic deformation of said body during
its said insertion, said body being of material permitting its said
substantial compression and plastic deformation during its said
insertion and, after such insertion, causing the body outer
periphery to frictionally engage the surrounding wall of the bore
for frictionally anchoring the structure, the ratio of the length
of said body to the outer diameter thereof being at least about 16
to 1, the ratio of the radial thickness of said body to the outer
diameter thereof being at a maximum about 1 to 5 and at a minimum
about 1 to 50, and the outer circumferential dimension of said body
being at least two inches.
2. A friction stabilizer according to claim 1, wherein the
circumferential width of said slot is at a maximum about 25 percent
of the outer circumferential dimension of said body.
3. A friction stabilizer according to claim 1, wherein the outer
periphery of said body is at least substantially imperforate.
4. A friction stabilizer according to claim 1, wherein said slot is
straight from end-to-end of said body.
5. A friction stabilizer according to claim 1, wherein the interior
of said body is open.
6. A friction stabilizer according to claim 1, further comprising
means for tensioning said body after its insertion in a bore.
7. A friction stabilizer according to claim 1, further comprising
wedge means movable internally of an end of said body. .Iadd.
8. A friction stabilizer for insertion in a bore in a structure
such as a roof or side wall of a mine shaft or other underground
opening for anchoring the structure, said stabilizer comprising
when inserted a generally annular body arranged to permit when
inserted substantial circumferential compression of said body
against the surrounding wall of the bore, said body being of
substantially the same transverse dimension along substantially its
full length, said body being of outer diameter predetermined to be
substantially larger than the diameter of the bore in which it is
to be inserted such that insertion of said body in such bore causes
substantial circumferential compression of said body, said body
being dimensioned to be plastically deformed during its insertion
in such bore, the stabilizer being free of structure precluding
such substantial compression and plastic deformation of said body
during its said insertion, said body being of material permitting
its said substantial circumferential compression and transverse
plastic deformation after said insertion in the event of a shift of
said structure in a plane transverse to the length of said
stabilizer, and, after such insertion, causing the body outer
periphery to frictionally engage the surrounding wall of the bore
for frictionally anchoring the structure, the ratio of the length
of said body to the outer diameter thereof being at least about 16
to 1, the ratio of the radial thickness of said body to the outer
diameter thereof being at a maximum about 1 to 5 and at a minimum
about 1 to 50, and the outer circumferential dimension of said body
being at least two inches. .Iaddend. .Iadd.
9. A friction stabilizer, according to claim 8, wherein:
said material comprises means plastically responsive to diverse,
radial-component forces applied to said body, as by a surface of
said surrounding wall of the bore, substantially fully along a
continuous and substantially full length of said body to effect an
engagement of said body with said surrounding wall of the bore with
a given, substantially uniformly distributed, anchoring force.
.Iaddend. .Iadd.
10. A friction stabilizer, according to claim 9, wherein:
said material further comprises means which, responsive to an axial
translation of said stabilizer due to strata separation of said
structure or the like, causes said body to retain such engagement
with substantially all said given anchoring force. .Iaddend.
.Iadd.
11. A friction stabilizer for insertion in a bore in a structure
such as a roof or side wall of a mine shaft or other underground
opening for anchoring the structure, said stabilizer comprising
when inserted a generally annular body arranged to permit when
inserted substantial circumferential compression of said body
against the surrounding wall of the bore, said body being of
substantially the same transverse dimension along substantially its
full length, said body being of outer diameter predetermined to be
substantially larger than the diameter of the bore in which it is
to be inserted such that insertion of said body in such bore causes
substantial circumferential compression of said body, said body
being dimensioned to be plastically deformed during its insertion
in such bore, the stabilizer being free of structure precluding
such substantial compression and plastic deformation of said body
during its said insertion, said body being of material permitting
its said substantial circumferential compression and transverse
plastic deformation after said insertion in the event of a shift of
said structure in a plane transverse to the length of said
stabilizer, and, after such insertion, causing the body outer
periphery to frictionally engage the surrounding wall of the bore
for frictionally anchoring the structure, and wherein said material
comprises means plastically responsive to diverse, radial-component
forces applied to said body, as by a surface of said surrounding
wall of the bore, substantially fully along a continuous and
substantially full length of said body to effect an engagement of
said body with said surrounding wall of the bore with a given,
substantially uniformly distributed, anchoring force. .Iaddend.
.Iadd.
12. A friction stabilizer for insertion in a bore in a structure
such as a roof or side wall of a mine shaft or other underground
opening for anchoring the structure, said stabilizer comprising
when inserted a generally annular body arranged to permit when
inserted substantial circumferential compression of said body
against the surrounding wall of the bore, said body being of
substantially the same transverse dimension along substantially its
full length, said body being of outer diameter predetermined to be
substantially larger than the diameter of the bore in which it is
to be inserted such that insertion of said body in such bore causes
substantial circumferential compression of said body, said body
being dimensioned to be plastically deformed during its insertion
in such bore, the stabilizer being free of structure precluding
such substantial compression and plastic deformation of said body
during its said insertion, said body being of material permitting
its said substantial circumferential compression and transverse
plastic deformation after said insertion in the event of a shift of
said structure in a plane transverse to the length of said
stabilizer, and, after such insertion, causing the body outer
periphery to frictionally engage the surrounding wall of the bore
for frictionally anchoring the structure, and wherein the material
comprises means which, responsive to an axial translation of said
stabilizer due to strata separation of said structure or the like,
causes said body to retain such engagement with substantially all
said given anchoring force. .Iaddend. .Iadd.
13. A friction stabilizer for insertion in a bore in a structure
such as a roof or side wall of a mine shaft or other underground
opening for anchoring the structure, said stabilizer comprising a
generally tubular body of substantially one cross-sectional
configuration along substantially its full length, said body having
a maximum transverse dimension predetermined to be larger than the
maximum transverse dimension of the bore in which it is to be
inserted, whereby insertion of said body in such bore causes
circumferential compression and deformation of said body, the
stabilizer being free of structure precluding such circumferential
compression and deformation of said body, and said body being of
material which, in response to a bore insertion of said stabilizer
(a) permits both said circumferential compression of said body, and
a transverse deformation thereof as well, in the event of a shift
in a plane transverse to the length of said stabilizer, of a
section or sections of any such bored structure in which said
stabilizer shall have been inserted; (b) causes said body, to
frictionally engage the wall of any such bore, thereby to anchor
the bored structure, substantially fully along a continuous and
substantially full length of said body, with a given, substantially
uniformly distributed, anchoring force; and which also (c)
maintains not less than substantially all said given anchoring
force, even in the event of partial or full collapse of said body
at some location therealong, in that portions of said body, defined
by or subsisting opposite any such collapse, apply some
proportionate anchoring forces to corresponding portions of such
bore wall thereabout, whether such portions of said body are
coaxially or linearly aligned with each other, or displaced or
shifted therebetween by any such collapse. .Iaddend. .Iadd.
14. A friction stabilizer, according to claim 13, wherein said
material comprises means plastically responsive to diverse,
radial-component forces applied to said body, by a surface of the
wall of a structure bore, upon said stabilizer being inserted into
such bore. .Iaddend. .Iadd.15. A friction stabilizer, according to
claim 13, wherein said material comprises means which, responsive
to an axial translation of said stabilizer, due to strata
separation, or the like, of a bored structure in which said
stabilizer shall have been inserted, causes said body to retain
such frictional engagement thereof with the wall of a bore in such
structure as to maintain substantially all said given anchoring
force. .Iaddend.
Description
The present invention relates to the anchoring of a structure such
as a roof or side wall of a mine shaft or other underground
opening, and more specifically to the provision of new and improved
friction rock stabilizers and stabilizing methods particularly
adapted for such anchoring.
An object of the present invention is to provide new and improved
friction rock stabilizers which are highly efficient in operation
while relatively simple and economical in construction.
.Iadd.It is particularly yet another object of this invention to
set forth a friction stabilizer for insertion in a bore in a
structure such as a roof or side wall of a mine shaft or other
underground opening for anchoring the structure, said stabilizer
comprising a generally tubular body of substantially one
cross-sectional configuration along substantially its full length,
said body having a maximum transverse dimension predetermined to be
larger than the maximum transverse dimension of the bore in which
it is to be inserted, whereby insertion of said body in such bore
causes circumferential compression and deformation of said body,
the stabilizer being free of structure precluding such
circumferential compression and deformation of said body, and said
body being of material which, in response to a bore insertion of
said stabilizer (a) permits both said circumferential compression
of said body, and a transverse deformation thereof as well, in the
event of a shift in a plane transverse to the length of said
stabilizer, of a section or sections of any such bored structure in
which said stabilizer shall have been inserted; (b) causes said
body to frictionally engage the wall of any such bore, thereby to
anchor the bored structure, substantially fully along a continuous
and substantially full length of said body, with a given,
substantially uniformly distributed, anchoring force; and which
also (c) maintains not less than substantially all said given
anchoring force, even in the event of partial or full collapse of
said body at some location therealong, in that portions of said
body, defined by or subsisting opposite any such collapse, apply
same proportionate anchoring forces to corresponding portions of
such bore wall thereabout, whether such portions of said body are
coaxially or linearly aligned with each other, or displaced or
shifted therebetween by any such collapse. .Iaddend.
Another object of the invention is to provide new and improved
stabilizing methods particularly adapted to provide highly
efficient anchoring through the employment of a stabilizer which is
relatively simple and economical in construction.
Other objects and advantages of the invention will be apparent from
the following description taken in connection with the accompanying
drawings wherein, as will be understood, the preferred forms of the
invention have been given by way of illustration only.
In accordance with the invention, a friction rock stabilizer may
comprise a generally annular body from end-to-end having a slot
through its thickness, the body including edge portions extending
along opposite sides of such a slot and the width of the slot being
sufficiently great to space apart such edge portions a distance
permitting substantial circumferential compression of the body for
insertion thereof in a bore of diameter smaller than the outer
diameter of the body in uncompressed condition, the anchor being
free of structure precluding such substantial circumferential
compression of the body, and the body being of material permitting
its said substantial circumferential compression for insertion in
such a bore and, after such insertion, causing the body outer
periphery to frictionally engage the surrounding wall of the bore
for anchoring a roof.
Also, in accordance with the invention, a structure such as a roof
or side wall of a mine shaft or other underground tunnel may be
anchored by a method which may comprise the steps of forming a bore
in the structure to be anchored, providing a circumferentially
compressible stabilizer having an outer periphery of a diameter
larger than that of the formed bore, and inserting the stabilizer
into the bore whereby the stabilizer is circumferentially
compressed and the outer periphery of the circumferentially
compressed stabilizer frictionally engages the wall of the
bore.
Referring to the drawings:
FIG. 1 is an elevational side view of one stabilizer constructed in
accordance with the present invention;
FIG. 2 is a top or plan view of the stabilizer illustrated in FIG.
1;
FIG. 3 is an elevational side view showing the stabilizer of FIG. 1
in operative position in a bore formed in the roof of a mine shaft
or other underground opening;
FIG. 4 is a sectional view of the stabilizer as shown in FIG. 3,
taken on Line 4-4 of FIG. 3 looking in the direction of the arrows;
and
FIG. 5 is a fragmentary, elevational sectional view of a second
stabilizer constructed in accordance with the invention showing
such in a bore in the roof of a mine shaft or other undergound
opening.
Referring more particularly to the drawings wherein similar
reference characters designate corresponding parts throughout the
several views, FIGS. 1 and 2 illustrate a friction rock stabilizer,
designated generally as 10, which, although relatively simple and
economical in construction, is highly efficient in anchoring a
structure such as a roof or side wall of a mine shaft or other
undergound opening. As shown in such FIGS., the stabilizer 10
consists of an elongated, generally annular, open-ended body 12
having a single, longitudinally extending, straight-slot 14 formed
through its radial thickness T from end-to-end, or throughout the
length, of the body 12. The body 12 is imperforate, cylindrical and
of constant outer diameter from end-to-end, the ratio of the length
of the body 12 to the outer diameter thereof being at least a
minimum of about 16 to 1 and preferably of about 32 to 1 or 48 to 1
although such longer stabilizers could be formed of interconnected
sections each of 16 to 1 ratio or greater. The opposite
longitudinal sides of the slot 14 are defined by opposed
longitudinally extending edge portions 16 of the body 12; and the
circumferential dimension or width W of the slot 14, with the body
12 in uncompressed condition, is sufficiently great to space apart
the edge portions 16 a circumferential distance permitting
substantial circumferential compression of the body 12 for
insertion thereof in a bore of diameter substantially smaller than
the outer diameter of the body 12. The outer circumferential
dimension of the body 12, not including the width W of the slot 14,
is greater than about two inches; and the width W of the slot 14 is
no greater than a maximum of about twenty-five percent of the
overall outer circumferential dimension of the stabilizer 10--that
is, no greater than about twenty-five percent of the complete
annulus formed by the body 12 and slot 14.
The body 12 is constructed of steel, thus permitting its
substantial circumferential compression for insertion in such a
substantially smaller diameter bore and, after such insertion,
causing the body outer circumference to frictionally engage the
surrounding wall of the bore for anchoring a structure such as the
roof of a mine shaft. Also, as will be noted, the anchor 10 is
entirely free of structure precluding such substantial
circumferential compression of the body 12, the interior 18 of the
body 12 being open or empty. The outer diameter of the body 12 of
the stabilizer 10 for any given size bore is pre-determined to be
substantially larger than the diameter of the bore, but such that
the edge portions 16 of the body 12 will be abutting, or spaced
apart by only a relatively small gap, with the stabilizer 10
installed in the bore. The ratio of the radial thickness T of the
body 12 to the body outer diameter is no greater than a maximum of
about 1 to 5 and no less than a minimum of about 1 to 50, thereby
permitting plastic deformation of the body 12 during its insertion
in the bore; and, although the body 12 has been shown as being of
constant outer diameter from end-to-end, the outer diameter of the
body forward or leading end could be of lesser outer diameter than
the remainder of the body 12 to facilitate said insertion.
FIGS. 3 and 4 illustrate the stabilizer 10 of FIGS. 1 and 2 in
installed condition in a pre-drilled bore 20 in a roof 22 to be
anchored thereby. During such insertion, the body 12 of the
stabilizer 10 is deformed plastically (that is, deformed in the
plastic range) to a condition whereby
.DELTA.--being the difference between the outer diameter of the
body 12 before insertion and the outer diameter of the body 12
after insertion,
D--being the outer diameter of the body 12 before insertion,
t--being the radial thickness of the body 12,
E--being Young's Modulus, and
.SIGMA.y--being the yield stress of the material.
As shown, the outer circumference of the body 12 of the installed
stabilizer 10 frictionally engages the surrounding wall of the bore
20 throughout the length of the body 12; and the stabilizer 10
anchors by this frictional engagement of the outer circumference of
the body 12 with the wall of the bore 20. The body outer
circumference may, of course, be epoxy coated, roughened or
otherwise constructed to enhance its frictional engagement with the
bore wall; and, as illustrated, the body 12 of the stabilizer 10 is
of a length to extend substantially the entire length of the bore
20. The pull-out force of the installed stabilizer 10 is somewhat
greater than the installation or push-in force applied to the
stabilizer, thereby enabling such pull-out force to be
predetermined by knowledge of the applied push-in force.
FIG. 5, wherein parts similar to those shown in FIGS. 1 through 4
are designated by the corresponding reference numerals followed by
the suffix "a", fragmentarially illustrates a friction rock
stabilizer 10a which is different from the stabilizer 10 only in
that it further includes means for tensioning the body 12a after
its insertion into the bore 20a. More particularly, as shown in
FIG. 5, the body 12a of the stabilizer 10a is inserted into the
bore 20a such that a minor portion 24 (for example, a few inches)
of the length of the body 12a is external to the bore 20a. The
stabilizer 10a includes a plate 26 having a central opening 28
receiving the body 12a, the plate 26 being mounted along the lower
surface of the roof 22a; and the stabilizer 10 further includes a
wedge pin 30 inserted through aligned openings 32, 34 in the body
12a immediately beneath the plate 26 to tension the body 12a after
its insertion into the bore 20a.
If desired, either of the stabilizers 10, 10a could be provided
with a wedge, per se of any suitable configuration, which is
inserted into the innermost or leading end of its body 12, 12a
after the body 12, 12a has been installed in its bore 20, 20a in
the beforedescribed manner. Neither of the stabilizers 10, 10a,
however, requires such a wedge; and both of the stabilizers 10, 10a
will provide highly efficient and safe anchoring without a wedge.
Moreover, in the event that a wedge is employed with either of the
stabilizers 10 or 10a, it must be disposed during the insertion of
the stabilizer body 12 or 12a into its bore 20 or 20a to preclude
it from interference with the beforedescribed substantial
circumferential compression of the body 12 or 12a occurring during
such insertion.
The methods of the invention may, generally considered, comprise
the steps of forming a bore 20 in the structure to be anchored,
providing a circumferentially compressible stabilizer 10 having an
outer circumference of a diameter larger than that of the formed
bore 20, and inserting the stabilizer 10 into the bore 20 whereby
the body of the stabilizer 10 is circumferentially compressed
during such insertion, thereby at least substantially closing the
slot 14, and the outer circumference of the circumferentially
compressed body 12 frictionally engages the wall of the bore 20 for
anchoring the structure.
From the preceding description, it will be seen that the invention
provides new and improved stabilizers and methods, for attaining
all of the aforestated objects and advantages. It will be
understood, however, that although only two embodiments of the
invention have been illustrated and hereinbefore described, the
invention is not limited merely to these two embodiments, but
rather contemplates other embodiments and variations within the
scope of the following claims.
* * * * *