U.S. patent number 10,294,788 [Application Number 15/657,676] was granted by the patent office on 2019-05-21 for slotted tubular anchor.
This patent grant is currently assigned to FCI Holdings Delaware, Inc.. The grantee listed for this patent is FCI Holdings Delaware, Inc.. Invention is credited to Dakota Faulkner, David Rager, John C. Stankus.
United States Patent |
10,294,788 |
Stankus , et al. |
May 21, 2019 |
Slotted tubular anchor
Abstract
A mine bolt includes an elongated body having a first end and a
second end positioned opposite the first end, and an anchor
comprising a tube defining a central opening and a slot extending
at least a portion of the length of the tube. The anchor is secured
to the elongated body. The anchor is configured to compress upon
installation of the mine bolt to anchor the elongated body within a
bore hole.
Inventors: |
Stankus; John C. (Canonsburg,
PA), Faulkner; Dakota (New Kensington, PA), Rager;
David (McKeesport, PA) |
Applicant: |
Name |
City |
State |
Country |
Type |
FCI Holdings Delaware, Inc. |
Wilmington |
DE |
US |
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Assignee: |
FCI Holdings Delaware, Inc.
(Wilmington, DE)
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Family
ID: |
60988300 |
Appl.
No.: |
15/657,676 |
Filed: |
July 24, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180023391 A1 |
Jan 25, 2018 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62366345 |
Jul 25, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21D
21/008 (20130101); E21D 20/00 (20130101); E21D
21/0053 (20160101) |
Current International
Class: |
E21D
21/00 (20060101); E21D 20/00 (20060101) |
Field of
Search: |
;405/259.1,259.3 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Andrish; Sean D
Attorney, Agent or Firm: The Webb Law Firm
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Patent
Application No. 62/366,345, filed Jul. 25, 2016, the entire content
of which is hereby incorporated by reference.
Claims
The invention claimed is:
1. A mine bolt comprising: an elongated body having a first end and
a second end positioned opposite the first end; and an anchor
comprising a tube defining a central opening and a slot extending
at least a portion of a length of the tube, the anchor is secured
to the elongated body, wherein: the anchor is configured to
compress upon installation of the mine bolt to anchor the elongated
body within a bore hole; the anchor comprises a nut with an outer
diameter, the nut is welded to the tube and positioned within the
central opening, the elongated body having a threaded portion
configured to be received by the nut; and the outer diameter of the
nut being smaller than a diameter of the central opening of the
anchor.
2. The mine bolt of claim 1, wherein the threaded portion is
positioned at the first end of the elongated body.
3. The mine bolt of claim 1, wherein the anchor includes a tapered
first end and a second end positioned opposite the tapered first
end.
4. The mine bolt of claim 3, wherein the tapered first end defines
a slit.
5. The mine bolt of claim 1, wherein the anchor extends from the
first end of the elongated body to a position intermediate the
first end and the second end of the elongated body.
6. The mine bolt of claim 1, wherein the second end of the
elongated body comprises a drive head.
7. The mine bolt of claim 1, further comprising a bearing plate
configured to receive the elongated body.
8. The mine bolt of claim 1, wherein the nut is hexagonal in
shape.
9. A mine bolt comprising: an elongated body having a first end and
a second end positioned opposite the first end; and an anchor
comprising a tube defining a central opening and a slot extending
at least a portion of a length of the tube, the anchor is secured
to the elongated body, wherein: the anchor is configured to
compress upon installation of the mine bolt to anchor the elongated
body within a bore hole; the anchor comprises a nut with an outer
diameter, the nut is secured to the tube and positioned within the
central opening, the elongated body having a threaded portion
configured to be received by the nut; the outer diameter of the nut
being smaller than a diameter of the central opening of the anchor;
the anchor includes a tapered first end and a second end positioned
opposite the tapered first end; and the second end of the anchor
defines a plurality of slits configured to engage a bore hole wall
when the mine bolt is installed and placed under loading.
10. A mine bolt comprising: an elongated body having a first end
and a second end positioned opposite the first end; and an anchor
comprising a tube defining a central opening and a slot extending
at least a portion of a length of the tube, the anchor is secured
to the elongated body, wherein: the anchor is configured to
compress upon installation of the mine bolt to anchor the elongated
body within a bore hole; the anchor comprises a nut with an outer
diameter, the nut is secured to the tube and positioned within the
central opening, the elongated body having a threaded portion
configured to be received by the nut; the outer diameter of the nut
being smaller than a diameter of the central opening of the anchor;
and 40-50% of an outer circumference of the nut is welded to the
tube.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
This invention is related to a mine bolt and, more particularly, to
a mine bolt having an anchor for securing the mine bolt within a
bore hole.
Description of Related Art
The roof/ribs of a mine are conventionally supported by tensioning
the roof with steel bolts inserted into bore holes drilled in the
mine roof that reinforces the unsupported rock formation above the
mine roof. The end of the mine roof bolt may be anchored
mechanically to the rock formation by engagement of an expansion
assembly on the end of the mine roof bolt with the rock formation.
Alternatively, the mine roof bolt may be adhesively bonded to the
rock formation with a resin bonding material or a grout inserted or
pumped into the bore hole. A combination of mechanical anchoring
and resin bonding can also be employed by using both an expansion
assembly and resin bonding or grout material.
A mechanically anchored mine roof bolt typically includes an
expansion assembly threaded onto one end of the bolt shaft and a
drive head for rotating the bolt. A mine roof plate is positioned
between the drive head and the mine roof surface. The expansion
assembly generally includes a multi-prong shell supported by a
threaded ring and a plug threaded onto the end of the bolt. When
the prongs of the shell engage with rock surrounding a bore hole,
and the bolt is rotated about its longitudinal axis, the plug
threads downwardly on the shaft to expand the shell into tight
engagement with the rock thereby placing the bolt in tension
between the expansion assembly and the mine roof surface.
A further type of mine roof bolt utilizes a slotted steel tube,
which is inserted into the bore hole such that the slotted steel
tube is compressed to provide radial and axial restraint to rock
movement.
SUMMARY OF THE INVENTION
In one aspect, a mine bolt includes an elongated body having a
first end and a second end positioned opposite the first end, and
an anchor comprising a tube defining a central opening and a slot
extending at least a portion of the length of the tube. The anchor
is secured to the elongated body. The anchor is configured to
compress upon installation of the mine bolt to anchor the elongated
body within a bore hole.
The anchor may include a nut secured to the tube and positioned
within the central opening, with the elongated body having a
threaded portion configured to be received by the nut. The nut may
be welded to the tube. The threaded portion may be positioned at
the first end of the elongated body. The anchor may include a
tapered first end and a second end positioned opposite the tapered
first end. The second end of the anchor may define a plurality of
slits configured to engage a bore hole wall when the mine bolt is
installed and placed under loading. The tapered first end may
define a slit. The anchor may extend from the first end of the
elongated body to a position intermediate the first end and the
second end of the elongated body. The elongated body may be axially
and rotationally moveable relative to the anchor. The second end of
the elongated body may include a drive head. The mine bolt may
further include a bearing plate configured to receive the elongated
body. The anchor may include an unthreaded nut secured to the tube
and positioned within the central opening, with the elongated body
having first and second support nuts received by a threaded
position of the elongated body, and with the first and second
support nuts configured to restrict the axial movement of the
elongated body relative to the unthreaded nut and the anchor.
In a further aspect, a method of installing a mine bolt includes
providing a mine bolt including an elongated body having a first
end and a second end positioned opposite the first end, and an
anchor comprising a tube defining a central opening and a slot
extending at least a portion of the length of the tube, with the
anchor secured to the elongated body. The method further including
inserting the mine bolt into a bore hole with the anchor
compressing as the anchor is inserted into the bore hole.
The mine bolt may be inserted into the bore hole until the second
end of the elongated body is positioned at an opening of the bore
hole. The method may further include providing a bearing plate that
receives the elongated body, and tensioning the mine bolt by
rotating the elongated body about a longitudinal axis to move the
elongated body axially relative to the anchor.
The anchor may include a nut secured to the tube and positioned
within the central opening, with the elongated body having a
threaded portion received by the nut. The second end of the
elongated body may include a drive head, with the elongated body
being rotated by engaging the drive head of the elongated body. The
anchor may include a tapered first end and a second end positioned
opposite the tapered first end, with the tapered first end being
the first portion of the mine bolt inserted into the bore hole. The
elongated body may include a drill bit. The anchor may include an
unthreaded nut secured to the tube and positioned within the
central opening, with the elongated body having first and second
support nuts received by a threaded position of the elongated body,
and with the first and second support nuts configured to restrict
the axial movement of the elongated body relative to the unthreaded
nut and the anchor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front perspective view of a mine bolt according to one
aspect of the present invention.
FIG. 2 is a cross-sectional view along line 2-2 shown in FIG.
1.
FIG. 3 is a front view of an anchor for a mine bolt according to
one aspect of the present invention.
FIG. 4 is front view of the mine bolt of FIG. 1, showing the mine
bolt installed in a bore hole.
FIG. 5 is a cross-sectional view along line 5-5 shown in FIG.
4.
FIG. 6 is a front perspective view of an anchor for a mine bolt
according to one aspect of the present invention.
FIG. 7 is an enlarged front perspective view of the anchor of FIG.
6.
FIG. 8 is a bottom perspective view of the anchor of FIG. 6.
FIG. 9 is a top perspective view of the anchor of FIG. 6.
FIG. 10 is a front perspective view of a mine bolt according to one
aspect of the present invention.
FIG. 11 is a partial cross-sectional view of a mine bolt according
to a further aspect of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will now be described with reference to the
accompanying figures. For purposes of the description hereinafter,
the terms "upper", "lower", "right", "left", "vertical",
"horizontal", "top", "bottom", and derivatives thereof shall relate
to the invention as it is oriented in the drawing figures. However,
it is to be understood that the invention may assume various
alternative variations and step sequences, except where expressly
specified to the contrary. It is to be understood that the specific
apparatus illustrated in the attached figures and described in the
following specification is simply an exemplary embodiment of the
present invention. Hence, specific dimensions and other physical
characteristics related to the embodiments disclosed herein are not
to be considered as limiting.
Referring to FIGS. 1-10, a mine bolt 10 according to one aspect of
the present invention includes an elongated body 12 having a first
end 14 and a second end 16 positioned opposite the first end 14.
The first end 14 of the elongated body 12 includes a threaded
portion 18. The second end 16 of the elongated body 12 includes a
drive head 20, which may be formed integrally with the elongated
body 12 or may be provided as a nut that is threaded onto the
second end 16 of the elongated body 12. The elongated body 12 may
be made of steel, although other suitable materials may be
utilized. The elongated body 12 may be smooth or deformed bars with
UNC or metric threads, such as rebar or J-Bar commercially
available from Jennmar. The elongated body 12 may also be hollow or
solid core bar with rope thread (R32) or hot rolled threaded bar,
such as the JM threaded bar commercially available from Jennmar.
The mine bolt 10 also includes an anchor 26 formed by a tube that
defines a central opening 28 and a slot 30 that extends the length
of the anchor 26, although the slot 30 may only extend a portion of
the length of the anchor 26.
As discussed in more detail below, the anchor 26 is configured to
secure the elongated body 12 within a bore hole. The anchor 26
further includes a nut 32 secured to the anchor 26 and positioned
within the central opening 28. The threaded portion 18 of the
elongated body 12 is threaded into the nut 32 to secure the
elongated body 12 to the anchor 26. The nut 32 is secured to the
anchor 26 via a weld 34, although any other suitable mechanical
fastening may be utilized. Furthermore, although the nut 32 is
utilized, any other suitable arrangement for securing the elongated
body 12 to the anchor 26 may be utilized. The anchor 26 includes a
tapered first end 36 and a second end 38 positioned opposite the
tapered first end 36. The tapered first end 36 has a smaller
diameter than the remaining portion of the anchor 26. The tapered
first end 36 of the anchor 26 allows the anchor 26 to be inserted
into the bore hole with the anchor 26 radially compressing as the
anchor 26 is inserted into the bore hole thereby providing a radial
force to secure the mine bolt 10 within the bore hole. In other
words, when the anchor 26 is radially compressed, the anchor 26
wants to return to its original position thereby providing a
biasing force radially outward. The first end 36 of the anchor 26
may define at least one slit 40 to facilitate providing the taper
of the first end 36 during manufacture of the anchor 26. The slit
40 may extend for part of or the entire tapered portion of the
first end 36 of the anchor 26. As shown in FIGS. 2 and 6-9, the nut
32 is secured to one side of the anchor 26 such that the anchor 26
is still free to compress and move with the irregularities of the
bore hole during installation of the mine bolt 10. The diameter of
the nut 32 is smaller than the diameter of the central opening 28
of the anchor 26. The extent to which the nut 32 is attached (e.g.
welded) to the anchor 26 impacts the degree to which the anchor 26
can compress radially. As such, minimizing the attachment area
between the nut 32 and the anchor 26 will increase the amount of
flex and "spring" in the anchor 26. However, the nut 32 must be
sufficiently attached to a degree such that upon loading of the
mine bolt 10, the nut 32 remains fixed to the anchor 26. In one
aspect, 40-50% of the circumference of the nut 32 is welded to the
anchor 26.
Referring to FIG. 3, the second end 38 of the anchor 26 may further
include a plurality of slits 42 configured to engage rock strata
when the mine bolt 10 is installed in a bore hole and placed under
loading. The slits 42 extend from the second end 38 of the anchor
26 to a position intermediate the first 36 and second end 38 of the
anchor. Although not shown, the second end 38 of the anchor 26 may
also be flared radially outward to further ensure the anchor 26
engages the rock strata defining the bore hole. The slits 42 may be
configured to allow the second end 38 of the anchor 26 to be flared
radially outward.
Referring to FIGS. 4 and 5, the mine bolt 10 is shown installed in
a bore hole 50. The mine bolt 10 is shown installed with a bearing
plate 52, although other suitable arrangements may be utilized. In
particular, the mine bolt 10 may further include a corrosion
protection sleeve and may also be configured to be grouted during
installation. As shown in FIG. 5, the anchor 26 engages rock strata
54 defining the bore hole 50 with the outwardly biasing force of
the anchor 26 securing the anchor 26 and the elongated body 12
within the bore hole 50. In other words, the compression of the
anchor 26 secures the anchor 26 within the bore hole 50 to
withstand axial and radial forces with the elongated body 12
secured to the anchor 26 via the nut 32. The anchor 26 is
compressed as the anchor 26 is inserted into the bore hole 50 with
the tapered first end 36 of the anchor 26 being the first position
of the mine bolt 10 inserted into the bore hole. Upon loading, the
second end 38 of the anchor 26 may be configured to engage the rock
strata 54 by providing the plurality of slits 42, serrations (not
shown), and/or flaring the second end 38 of the anchor 26. After
being anchored, the mine bolt 10 may be tensioned by rotating the
drive head 20 to rotate the elongated body 12 about its
longitudinal axis relative to the nut 32 and the anchor 26 such
that the bearing plate 52 engages the rock strata 54 adjacent to
the opening of the bore hole 50. The mine bolt 10 is inserted into
the bore hole 50 until the second end 16 of the elongated body 12
is positioned at an opening of the bore hole 50.
Referring to FIG. 11, a mine bolt 100 according to a further aspect
of the present invention is shown. The mine bolt 100 is similar to
the mine bolt shown in FIGS. 1-10 discussed above. The mine bolt
100, however, is a self-drilling bolt and includes a drill bit 102
secured to the first end 14 of the elongated body 12. The drill bit
102 may be threaded onto the threaded portion 18 of the second end,
although other suitable securing arrangements may be utilized.
Further, in order to allow the drill bit 102 to drill the bore hole
50 in the rock strata 54, the first end 14 of the elongated body 12
and the drill bit 102 are positioned outside of the anchor 26 and
extend beyond the first end 36 of the anchor 26. The nut 32 of the
mine bolt 100 is secured to the anchor 26 in the same manner as
described above in connection with the mine bolt 10 shown in FIGS.
1-10. The nut 32 of the mine bolt 100, however, is unthreaded to
allow the elongated body 12 to rotate independently from the nut 32
and the anchor 26. The axial position of the elongated body 12 is
fixed by first and second support nuts 104, 106 positioned on each
side of the nut 32. The support nuts 104, 106 are threaded onto the
threaded portion 18 of the elongated body 12 with the first support
nut positioned closer to the first end 14 of the elongated body 12
relative to the nut 32 and the second support nut position closer
to the second end 16 of the elongated body 12. Accordingly, the
first and second support nuts 104, 106 fix the axial location of
the elongated body 12 relative to the nut 32 and the anchor 26
while allowing the elongated body 12 and drill bit 102 to rotate
independently from the nut 32 and anchor 26 during a drilling
operation using the mine bolt 100.
The anchor 26 of the mine bolt 100 operates in the same manner as
discussed above in connection with the mine bolt 10 shown in FIGS.
1-10. In particular, the drill bit 102 drills the bore hole 50 in
the rock strata 54 by rotating the elongated body 12 with the
anchor 26 being compressed as the anchor 26 enters the bore hole 50
drilled by the drill bit 102. The anchor 26 continues to advance
within the bore hole 50 as the drilling process continues. Upon
reaching the desired bore hole 50 depth, the drill process ceases
with the drill bit 102 remaining in the bore hole 50 and the anchor
26 securing the mine bolt 100 within bore hole 50. The mine bolt
100 may be tensioned in the same manner as mine bolt 10.
While several embodiments were described in the foregoing detailed
description, those skilled in the art may make modifications and
alterations to these embodiments without departing from the scope
and spirit of the invention. Accordingly, the foregoing description
is intended to be illustrative rather than restrictive.
* * * * *