Note: Descriptions are shown in the official language in which they were submitted.
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Docket No.: 0311-IR-RD
A DYNAMIC EARTH ANCHOR, AND A SLEEVE THEREFOR
Background of the Invention
This invention pertains to dynamic earth anchors, or
rock stabilizing fixtures, as the same are also identified,
and in particular to such earth anchor so conceived as to
facilitate either the insertion of a rock bolt-receiving
sleeve into the terrestrial formation borehole, or the
insertion of the rock bolt into the sleeve, as well as to
sleeves of and for such earth anchors.
Dynamic earth anchors, or rock stabilizing fixtures,
are well known. Exemplary thereof is the Dynamic Rock
Stabilizing Fixture" set forth the U.S. Patent No. Re 32645
and issued to James J. Scott.
The fixture in the aforesaid patent comprises a
sleeve having a hollow body which is inserted into the end
of a terrestrial borehole, and a rock bolt which is then
inserted into the borehole-seated sleeve. Typically, the
bolt will have threads or other disruptions on the surface
thereof to enhance its fast engagement with the sleeve.
The combination sets up an almost immediate restraint of
the terrestrial formation, and accommodates a roof plate,
or the like, at the formation face.
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Due to discontinuities and/or asperities in the
sleeve-receiving borehole, it is frequently difficult to
set the sleeve into the termination of the borehole;
difficulties are commonly encountered in inserting the
rock bolt into the seated sleeve.
The foregoing illustrates limitations known to
exist in present devices. Thus, it is apparent that it
would be advantageous to provide an alternative directed
to overcoming one or more of the limitations set forth
above. Accordingly, a suitable alternative is provided
including features more fully described hereinafter.
Summary of the Invention
In one aspect of the invention, this is
accomplished by a sleeve, for use in such an aforesaid
dynamic earth anchor, for insertion thereof into a
terrestrial borehole, and for insertion thereinto of a
roof bolt, comprising a hollow body defining an endless
wall; the body being formed of deformable material; and
the wall having a conformation for facilitating at least
one of the aforesaid insertions.
According to a further broad aspect of the present
invention, there is provided an apparatus comprising a
sleeve insertable into a borehole, the said borehole
having an inner diameter. A roof pin, to be inserted
into the sleeve, has an outer diameter which is less
than the borehole inner diameter. The sleeve has a
continuous, circumferential outer surface without any
structural interruptions. The outer surface having a
uniform sleeve outer diameter equal to or smaller than
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the borehole inner diameter after insertion of the
sleeve into the borehole and prior to insertion of the
roof pin into the sleeve. The sleeve has an inner
surface containing at least one longitudinally extending
yieldable channel portion which has a lesser thickness
than the remainder of the sleeve, sufficient
circumferential expansion of the channel portions
permitting circumferential expansion of the sleeve to
establish a restraint between the roof pin and the
borehole.
According to a further broad aspect of the present
invention, there is provided an apparatus which
comprises a sleeve insertable into a borehole, the
borehole having an inner diameter, and the sleeve, when
undeformed, having an outer diameter equal to or smaller
than the borehole inner diameter. A roof pin, to be
inserted into the sleeve, has an outer diameter which is
less than the borehole inner diameter. The sleeve has a
continuous, circumferential inner surface without any
structural interruptions. The inner surface has a
uniform sleeve inner diameter after insertion of the
sleeve into the borehole and prior to insertion of the
roof pin into the sleeve. The sleeve has an outer
surface containing at least one longitudinally extending
yieldable channel portion which has a lesser thickness
than the remainder of the sleeve, sufficient
circumferential expansion of the channel portions
permitting circumferential expansion of the sleeve to
establish a restraint between the roof pin and the
borehole. The sleeve has a first and second axial end.
The channel extends spirally between the first and the
second axial ends of the sleeve.
According to a still further broad aspect of the
present invention, there is provided an anchor
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for stabilizing a terrestrial formation. The anchor
comprises a sleeve insertable into a borehole formed in
the terrestrial formation. The borehole has an inner
diameter, the sleeve, when undeformed, having an outer
diameter equal to or smaller than the inner diameter.
A pin is insertable into the sleeve and has an outer
diameter less than the borehole inner diameter. The
sleeve has a substantially cylindrical continuous
peripheral outer surface and an inner surface. The
peripheral outer surface has a substantially constant
sleeve outer diameter after insertion of the sleeve into
the borehole and prior to insertion of the pin into the
sleeve. The inner surface has a longitudinally extending
yieldable channel portion with a lesser sleeve thickness
lS than the remainder of the sleeve, sufficient
circumferential expansion of the channel portions
permitting radial expansion of the sleeve outer diameter
upon insertion of the pin into the sleeve to establish
anchoring between the sleeve and the borehole.
The foregoing and other aspects will become apparent
from the following detailed description of the invention
when considered in conjunction with the accompanying drawing
figures. It is to be expressly understood, however, that
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Docket No.: 0311-IR-RD
the drawing figures are not intended as a definition of the
invention but are for the purpose of illustration only.
Brief Description of the Drawing Figures
s
In the drawing:
Fig. 1 is a perspective illustration of a first
embodiment of the novel sleeve;
Fig. 2 is a depiction of the leading end of a threaded
roof bolt made fast in the sleeve of Fig. 1, the same
comprising an embodiment of the novel dynamic earth anchor:
Fig. 3 is a perspective illustration of a second
embodiment of the novel sleeve;
Fig. 4 is a perspective depiction of a third
embodiment of the inventive sleeve;
Figs. 5, 6, and 7 are longitudinal cross-sectional
views of further embodiments of the sleeve of the invention;
and
Fig. ~ illustrates a channel spirally disposed along
the elongated outer surface of the sleeve body.
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Docket No.: 0311-IR-RD
Detailed Description
As shown in Fig. 1, a sleeve 10, according to this
embodiment thereof, comprises a body 12 which is hollow,
defining the same as an endless wall. The body is formed of
a deformable plastic material, and has four, equally-spaced
apart channels 14 formed in the outer surface thereof. Now,
the outer diameter of the sleeve 10 is substantially
identical to that of the borehole into which it is to be
inserted, and the inside diameter thereof is smaller than
the greatest outside diameter of the roof bolt or rock bolt
which is to be inserted into the sleeve. (For the purposes
of this disclosure, roof bolt and rock bolt will be used
interchangeably, as they mean the same thing.) Clearly, it
requires some reasonable force to get the leading end of a
roof bolt fully inserted into the undersized sleeve 10.
Consequently, to minimize the force required, the channels
14 are provided as yieldable portions of the sleeve 10 which
can splay and widen, before the inserting roof bolt, to make
bolt entry easier to accomplish. As represented in Fig. 2,
the roof bolt 16 has entered the sleeve 10 and the channels
have spread to give it entry.
` The sleeve of Fig. 3 is an alternative embodiment in
which there is but a single yieldable channel 20, and here
the latter is formed in the inner surface of the sleeve.
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Docket No.: 0311-IR-RD
Where the embodiments of Figs. 1 through 3 depicted
sleeves 10 and 18 configured to facilitate the entry of the
roof bolt 16 thereinto, Fig. 4 shows an embodiment of a
sleeve 22 which is an overall, outermost dimension which is
smaller than the diameter of the borehole into which it is
to be inserted. This embodiment is set forth to facilitate
the entry of the sleeve 22 into the borehole without undue
difficulty. The borehole is represented by the dashed
outline, and the sleeve 22, of a substantially cruciform
shape, is somewhat collapsed. The flutes or depressions 24
obtaining between the lobes 26 will expand, upon the
insertion of a roof bolt thereinto, and the sleeve 22 will
assume a circular shape and be pressed firmly into the wall
of the borehole. This embodiment may also include a channel
20a.
Figs. 5, 6 and 7 show, in longitudinal cross-section,
further embodiments of sleeves 28, 30, 32, respectively,
which are configured to facilitate their entry into a
borehole. Sleeve 28 has a tapered front or leading end 34.
Sleeve 30 has a taper running the fully length thereof, with
the narrowest portion being at the leading end, i.e., the
bore entry end, thereof. Sleeve 32 is similar to sleeve 28;
it is tapered only at the leading end thereof. In addition,
however, sleeve 32 has a knife edge 36 at the termination of
the taper. This offers a particular advantage. Frequently,
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Docket No.: 0311-IR-RD
such sleeves used in dynamic earth anchors are grouted in
place. To this end, a cartridge of grout is placed in the
borehole in advance of the sleeve. The knife edge 36 of
sleeve 32 will, when forced into the borehole, following the
insertion of a cartridge of grout, rupture the grout
cartridge, and permit the grout to flow.
Reverting to the sleeve 10, of Fig. 1, and having
remarked about the use of grout, it is to be noted that the
channels 14 will also serve as conduits for the flow of the
fluid grout along the length of the sleeve 10. Therefore, as
required in the circumstances, sleeve 10 can be modified to
incorporate a knife edge (such as 36 of sleeve 32), or sleeve
32 could be formed with channels (such as those in sleeve
10). These, and all other embodiments and modifications of
the novel sleeves, and the dynamic earth anchor (Fig. 2) of
which they are component parts, are deemed to be prefigured
by this disclosure, and embraced by the appended claims.
As a further alternative, Fig. 8 illustrates a spirally
disposed channel 40 formed to extend along an outer surface
42 of body 44. Channel 40 extends substantially between a
first end 46 and a second end 48 of body 44. Also, in Fig.
3, it is illustrated in dotted line, that channel 20 can be
spirally disposed along an inner surface of sleeve 18.
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Docket No.: 0311-IR-RD
Accordingly, while I have described my invention in
connection with specific embodiments thereof, it is to be
clearly understood that this is done only by way of example
and not as a limitation to the scope of my invention, as set
S forth in the appended claims.
