Note: Descriptions are shown in the official language in which they were submitted.
The present lnvention 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 pxovision of
new and improved friction rock stabilizers particularly adapted
for said anchoring of a structure such as a roof or side wall `-
of a mine shaft or other underground openlng.
My prior Canadian Patent No. 990,555, issued on June
8, 1976 dlscloses friction stabilizers of the general type to
which this invention is directed.
An object of the present invention is to provide a
new and improved friction stabilizer particularly constructed
and arranged to maximize the permissible dimensional tolerances
of the bore in which the stabilizer is to be installed.
Another object of the invent:ion is to provide a ne-~ ;
and improved friction stabilizer particularly constructed and
arranged to insure that, when installed, it forms a complete
annulus or ring without gap or space through its thic~ness.
Other objects and advantages o the invention will
become apparent from the following description taken in connec-
tion with the accompanying drawings wherein, as will be under-
stood, the perferred embodiments of the invention have been
given by way of illustration only. ~
In accordance with the invention, a friction stabilizer ,
may comprise a generally annular body having longitudinally
~xtending portions which overlap circumferentially of the
body, the body being of dimension predetermined to be substan-~
tially larger than the diameter of the bore in which it is to
be inserted such that insertion of the body in such bore causes
substantial circumferential compression of the body,
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the overlapping portions of the body being relatively movable
circumferentially of the body to permit such substantial cir- -
cumferential compression of the body, the stabilizer beiny free
of structure precluding such substantial circumferential com-
pression of the body, and the body being of material permitting
such substantial compression during its said insertion and,
after such insertion, causing the body outer circumference to
frictionally engage the wall of the bore for frictionally
anchoring the structure. The friction stabilizer is character-
ized in that the body is defined by inner and outer circumfer-
ential walls formed of a single thickness of the material, which
inner and outer walls, in cross-section, are of common annular
configuration. The inner and outer walls each have a prescribed,
common discontinuit~ which extends, uniformly, fully longitudi-
nally of the body. The discontinuities of the inner and outer
walls are spaced apart, one from the other thereof, circumfer-
entially of the body~
Referring to the drawings:
Fig. 1 is an elevational side view of one stabilizer
constructed in accordance with the present invention'
FigO 2 is a top or plan view of the stabilizer illus-
trated in Fig. 1,
Fig~ 3 is an elevational side view showing the stabilizer
of Fig.--l installed in a bore formed in a roof of a mine shaft
or other underground openin0,
Fig. 4 is a sectional view of such installed stabilizer
taken on line 4--4 of Fig. 3, looking in the direction of the
arrows,
Fig~ 5 is an elevational side view of a second stabilizer
constructed in accordance with the invention,
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Fig. 6 is a top or plan view of the stabilizer shown in
Fig. 5-
Fig. 7 is an elevational side view showing the stabilizer
of Fig~ 5 installed in a bore formed in a roof of a mine shat
or other underground opening, and
Fig~ 8 is a sectional view of the stabilizer of Fig. 7
taken on line 8-8 of Fig. 7, looking in the direction of the
arrows, .
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Referrin~ more par~icul~rly to the drawin~s wherein
$imilar reference characters designate corresponding parts ;;
throughout the several views, Figs. 1 and 2 illustrate one
embodiment of the invention i~ the form of a friction rock
stabilizer, designated generally as 10, in normal uncompressed
condition prior to its installation in a pre-formed bore in
the roof, side wall or other structure to be anchored. The
stabilizer 10 comprises an elongated, generally annular body
12 which is open ended and longitudinally split or slotted to
include a single slot 14 through its thickness from end-to-end,
or throughout the length, of the body 12. The slot 14 is ;
angled to extend generally circumferentially of the body 12
rather than constructed radially therethrough, thus causing
the body 12 throughout its length to include longitudinally
extending edge portions 16,18 which overlap one another cir-
cumferentially of the body 12 and terminate in opposed angled ~-
edges 20,22, extending at least generally longitudinally of
the body 12, on opposite sides of the slot 14. As shown in
Fig. 2, the edges 20,22 are formed at identical angles to a
20 radial plane through the thickness of the body 12; and, as
will be understood, the described angling of the edges 20,22
causes such to be readily slidable one over the other during
circumferential compression of the boay 12 and thereby facili-
tates movement of the edge portions 1~,18 relative to one
another during such circumferential compression.
The body 12 is (except for the slot 14) imperforate, gen-
erally cylindrical and of constant outer diameter from end-to-
end, it being understood, however, that the outer diameter of
the body forward or leading end (that is, the end of the body
12 intended to be first inserted in the pre-formed bore) could
be of slightly lesser outer diameter than the remainder of the
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body 12 to facilitate such insertion. The ratio of the length
of the body 12 to the maximum outer diameter thereof is at
least about 16 to 1 and preferably about 3~ to 1 or 48 to 1,
it being understood however that such longer st~bilizers could
be constructed of interconnected segments each of the mentioned
16 to 1 ratio or greater~ The outer circumferential dimension
of the body 12 is greater t~an about two inches.
The body 12 is constructed of steeI, thus permitting its
substantial circumferential compression for insertion in 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
interi~or of the body 12 being open or empty. The outer dia-
meter of the body 12 of the stabilizer 10 for installation in
any given size bore is predetermined to be substa~tially
larger than the diameter of the bore; and the ratio of the
radial thickness of the body 12 to the body maximum outer -
diameter is no greater than about 1 to 5 and no less than
about 1 to 50, thereby permitting plastic deformation of the
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body 12 during its insertion in the bore.
The beforedescribed stabilizer 10 can be readily con-
structed from tubular stock by merely forming or cutting the
angled slot 14 through the thickness of ~he stock throughout
its length. Also, as the precise width of the slot 14 is not
critical to the anchoring to be performed by the stabilizer
10 due to the described relationship of the edge portions
16,18, such width can be varied with~n a relatively wide range
and, if desired, the stabilizer can even be circumferentially
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compressed during its formation to dispose the edges 20,22 of
the edge portions 16,18 in abutting relationship~ Also, i~
desired, the stabilizer 1~ may be formed of sheet material
rolled to the illustrated configuration either with the edges
20,22 spaced apart by the described slot 14 or in abutting `
relationship.
Fi~s. 3 and 4 illustrate the stabilizer 10 of Figs. 1
and 2 in installed cQndition in a pre-formed bore 24 in a mine
or tunnel roof or other structure 26 to be anchored thereby,
it being understood that, as beforedescribed, the diameter of
the bore 24 is substantially smaller than the normal, uncom-
pressed o~ter diameter of the body 12 of the stabilizer 10.
The stabilizer 10 is installed in the bore 24 by substantially
circumferentially compressing the body 12 such that the body `
12 is deformed plastically tthat is deformed into the plastic
range and beyond the elastic range?, and thence longitudinally
inserting the compressed body 12 into the bore 24. During
such plastic deformation of the body 12, the edges 20,22 of
the edge portions 16,18 slide over one another to increase -
2Q the circumferential overlapping of the edge portions 16,18;
and, after insertion of the body 12 in the bore 2~ the resi-
lence of the body 12 causes the body outer circum~erence to
frictionally engage the surrounding wall of the bore 24 ~`
throughout the length of the body 12 and, aside from a minor `
portion 28 of its outer circumference, throughout the outer
circumference of the body 12. The stabilizer 1~ anchors by
this frictional engagement of the outer circumference of the
body 12 with the wall of the bore 24, the edge portions 16,18
being during this anchoring in the relationship shown in Fig.
4, whereby the body 12 forms a complate annulus or ring com-
pletely circumferentially enclosing the opening 30 therein and
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without gap or space through its radial thickness. Also, as
shown in Fig. 3, the stabilizer bo~y 12 is of len~th to extend
at least substantially t~roughout the length of the bore 24,
or alternatively a plurality of end-to-end stabilizers 10 are
disposed in the bore ~4 and interconnected with their bodies
l? cooperating to extend at least substantially the length of
the bore 24, whereby such frictional engagement occurs at
least substantially throughout such length of the bore 26.
Figs. 5 through 8 illustrate a second embodime~t of the
invention in the form of a friction rock stabilizer 32 which
is different from the beforedescribed stabilizer 10 only in
the relative arrangement of the overlapping portions of the
stabilizer body. ~ ~ -
Figs. 5 and 6 illustrate the stabilizer 32 in normal,
uncompressed condition prior to its installation in a pre-
formed bore in the structure to be anchored; and Figs. 7 and
8 illustrate such stabilizer 32 in anchoring position in a
pre-formed bore 34 in the mine roof or other structure 36 to ;`~
be anchored. As shown in Figs. 5 and 6, the stabilizer 32
comprises an elongated, generally annular, open ended body 38
which throughout its length includes longitudinally extending
edge portions 40,42 slidably overlapping one inside the other
circumferentially of the body 30. The edges 44,46 of the edge
portions 40,42, respectively, of course, may be of any desired
configuration and, as shown in Fig. 6, are offset circumferen-
tially of the body 30 with the stabilizer 32 in normal, un-
compressed condition. The body 38 is, as will be understood,
constructed of steel permitting its substantial circumferen-
tial compression for insertion in a substantially smaller
diameter bore and after such insertion causing the body outer
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circumference to frictionally engage the surrounding wall of
the bore for anchoring the structure containing the bore.
~he stabilizer 32 is, as again will be understood, entirely
free of structure precluding said circumferential compression
of the body 38; and the in-terior of the body 38 is entirely
open or empty. Also, the'outer diameter b the body 38 of ,
the stabilizer 32 for any given size bore is again predeter-
mined to be substantially larger than the diameter of the bore,
and the' ratio of the radial thickness of the material of the
body 38 to the body maximum outer diameter is no greater than
about 1 to 5 and no less than about 1 to 50, thereby permitting
plastic de~ormation of the body 38'during its installation in ~,
such a bore. Furthermore, the dimensional relationship or
ratio of the len~th of the body 38 to the maximum outer dia-
meter thereo~ is the same as that beforedescribed for thestabilizer 10, and the minimum outer circumferential dimension
of the body 38 is at least two inches.
The anchoring of the structure 36 by the stabilizer 32 ,,
;, - proceeds in the same manner beforedescribed for the anchoring
of the structure 26 by the stabilizer 1~ and hence is believed
to be readily apparent'rom the beforegiven description of the ';
anchoring of the structure 26 by such stabilizer 10, it being
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, ~nderstood that during such anchoring the body 38 is plasti-
cally deformed and the edge portions 40,42 are moved circum-
erentially o~ the body 38 ~rom their relative positions shown
; - in Fig. 6 to their relative positions shown in Fig. 8. The
installed stabilizer 32 frictionally anchors for all but the
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minor portion ~8 of its outer circumference throughout its
length. The opening 50 longitudinally through the'stabilizer "
body 38 is, as will be noted from Figs.'6 and 8, at all times
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completely circumferen~i?il~ enclosed by the body 38; ~n~ the
installed stabilizer 32 hence includes no gap or space through
its radial thickness. .:
From the preceding description, it will be seen that th~ ~.
invention provides new and ~mproved friction stabilizers for.
accomplishing all of the beforestated objects of the invention. ~; :
It will, moreover, be seen that during the anchoring of a
structure by either of the beforedescribed stabilizers 10,32, ;:
their beforedescribed respective edge portions slide over one
another circumferentially of the stabilizer body. ~lso, after . :~
installation, and during the anchoring, such overlapping edge .. .
portions establish a hoop stress in the stabilizer body to .-
increase the normal force against the side of the bore, there~
: by increasing the normal force against the wall of the bore .
and also increasing the anchoring force. It will be under-
stood that the overlapping edge portions of the stabilizers
10,32 may, if desired, be roughened on their opposing sur~
faces to increase friction between them and thereby increase
- the mentioned hoop stress; and it will also be seen that the
stabilizer bodies are deformed plastically and frictionally
engage the wall of the bore over most of their outer circum- .
ference, the plastic dsformation in the area of the overlapping `.
edge portions being, of course, the most severe.
~ It will be understood however that, although only two
embodiments of the invention have been illustrated and herein~
before specifically described, the invention is not limited
merely to these two embodiments but rather encompasses other
embodiments and variations within the scope of the following
claims. :.~
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