Note: Descriptions are shown in the official language in which they were submitted.
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BLASTHOLE DRILL WITH DRILL-THROUGH PIPE RACK
BACKGROUND OF THE INVENTION
Blasthole drills are large machines used in mining
operations to drill holes for explosives. A conventional
blasthole drill comprises a frame supported by crawlers for
movement over the ground, and a mast supported by the frame for
movement between a substantially vertical position and a number
of angled or non-vertical positions. The mast defines a drill
hole axis. A rotary head moves relative to the mast along the
drill hole axis. The rotary head engages the upper end of a
drill pipe for rotating the drill pipe and driving the drill pipe
into the ground. When drilling a blasthole that is deeper than
the height of the mast, more than one section of drill pipe must
be used. After the first section of drill pipe is driven into
the ground, the rotary head moves back to the top of the mast and
another section of drill pipe is connected to the top of the
first section. The rotary pipe then drives the second section
into the ground. It is not unusual to use four sections of drill
pipe. Such a deep blasthole is referred to as a "multi-pass"
blasthole. The various sections of drill pipe are supported
relative to the mast and moved into position (on the drill hole
axis) at the appropriate time by a device known as a pipe rack.
When drilling a multi-pass blasthole, a considerable
amount of time is spent in adding and removing individual drill
pipe sections from the drill string. Also, when drilling
blastholes at an angle, a considerable amount of time is spent
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engaging and disengaging a device known as a pipe positioner,
which aligns and supports the lower end of a suspended pipe
section (i.e., maintains the lower end of the pipe section on the
drill hole axis) during connection and removal from the lower
pipe string. Thus, a considerable amount of time is spent doing
things other than drilling.
A carousel-type drill-through pipe rack is known. The
carousel rack includes a circular plate which rotates about its
center and which supports the lower ends of a plurality of drill
pipes. The carousel must be extended to locate a pipe on the
drill hole axis and must be retracted to allow the rotary head to
pass.
SUMMARY OF THE INVENTION
The invention provides a drill-through pipe rack that
increases production in drilling vertical or angled multi-pass
holes. The bottom of the pipe rack supports and stores drill
pipe when the pipe is not in use. After the rack positions a
pipe section on the drill hole axis, the pipe rack remains open
to allow the drill pipe to pass through in order to add or remove
pipe sections without having to retract the pipe rack to its
stored position as with conventional designs. The pipe rack
requires less mast depth (i.e., less room) than known carousel-
type pipe racks. Also, the pipe rack of the invention does not
have to be retracted as fast (in order to allow the rotary head
to pass) as the known carousel-type rack.
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More particularly, the pipe rack of the invention
includes an upper arm with an inner end connected to the mast for
pivotal movement about a horizontal axis. The pipe rack also
includes a lower arm with an inner end connected to the mast for
pivotal movement about a horizontal inner axis. An elongated
rack member has an upper end connected to the outer end of the
upper arm for pivotal movement about a horizontal axis, and a
lower end connected to the outer end of the lower arm for pivotal
movement about a horizontal outer axis. The mast, the upper and
lower arms and the vertical rack member define a parallelogram
structure. A hydraulic cylinder pivots the upper and lower arms
relative to the mast between generally vertical and generally
horizontal positions. When the upper and lower arms are in their
vertical positions, the rack member is in a stored or retracted
position within the mast and away from the drill hole axis. When
the upper and lower arms are pivoted to their horizontal
positions, the rack member moves horizontally and downwardly to
an extended position adjacent the drill hole axis. When the rack
member is in its extended position, the lower arm is supported by
a support mounted on the mast bottom plate. The support prevents
over extending the hydraulic cylinder and also supports the rack
when breaking the top joint from the rotary head using rotary
machine torque.
The pipe rack actually moves "over center" as it moves
to its stored position. When the mast is in its vertical
position, the inner axis of the lower arm defines a vertical
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plane. When the mast is in the vertical position and the rack
member moves from the extended position to the retracted
position, the outer axis of the lower arm moves through the
vertical plane. As a result, when the rack member is in the
retracted position, gravity biases the rack member away from the
extended position. Therefore, if the hydraulic cylinder should
unexpectedly fail while the rack member is in the retracted
position, the rack member will not "fall" or move to the extended
position under the force of gravity. This protects both
personnel and equipment.
The pipe rack also includes upper and lower gates which
are mounted on the rack member and which support a drill pipe for
movement with the rack member. When the rack member is in its
extended position, a drill pipe supported by the gates is located
on the drill hole axis. The gates are selectively opened and
closed by hydraulics. The lower gate includes a shelf which
supports the lower end of a drill pipe when the gate is closed.
When the gate is opened, the shelf moves out from beneath the
drill pipe such that the drill pipe can move downwardly relative
to the gate.
The drill-through pipe rack reduces drill pipe addition
cycle time because the pipe rack does not have to be returned to
its stored position before the drill pipe begins downward
movement. Also, a lower drill pipe positioner is not required
because the lower gate maintains the position of the drill pipe
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during initial downward movement. Furthermore, drill
productivity is increased through shorter cycle time.
Other features and advantages of the invention will
become apparent to those skilled in the art upon review of the
following detailed description, claims and drawings.
DESCRIPTION OF THE DRAWINGS
Fig. 1 is a side elevational view of a blasthole drill
embodying the invention.
Fig. 2 is a view taken generally along line 2-2 in Fig.
1.
Fig. 3 is an enlarged, partial side elevational view of
the mast.
Fig. 4 is a side elevational view of the pipe rack with
the rack member in its retracted position.
Fig. 5 is a view similar to Fig. 4 showing the pipe
rack in its extended position.
Fig. 6 is an enlarged portion of Fig. 5.
Fig. 7 is a top plan view of the portion of the pipe
rack shown in Fig. 6.
Fig. 8 is a right side elevational view of the portion
of the pipe rack shown in Fig. 6.
Fig. 9 is a view similar to Fig. 8 showing the upper
gate opened.
Fig. 10 is an enlarged portion of Fig. 5.
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Fig. 11 is a top plan view of the portion of the pipe
rack shown in Fig. 10.
Fig. 12 is a view similar to Fig. 11 showing the lower
gate opened.
Fig. 13 is a horizontal sectional view of the lower
gate showing the pawls for engaging a drill pipe.
Fig. 14 is a partial view similar to Fig. 4 with the
over center feature of the pipe rack exaggerated.
Before one embodiment of the invention is explained in
detail, it is to be understood that the invention is not limited
in its application to the details of the construction and the
arrangements of components set forth in the following description
or illustrated in the drawings. The invention is capable of
other embodiments and of being practiced or being carried out in
various ways. Also, it is to be understood that the phraseology
and terminology used herein is for the purpose of description and
should not be regarded as limiting.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A blasthole drill 10 embodying the invention is
illustrated in Fig. 1. The blasthole drill 10 comprises a frame
14 supported by crawlers 18 for movement over the ground. A mast
22 is supported by the frame 14 for movement relative thereto
about a generally horizontal axis 26 and between a substantially
vertical position (shown in Fig. 1) and a number of angled or
non-vertical positions (not shown). The mast 22 defines a drill
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hole axis 30. A rotary head 34 is moveable relative to the mast
22 along the drill hole axis 30. The rotary head 34 is
selectively engageable with the upper end of a drill pipe 38
supported relative to the mast 22 (as described below). A pair
of deck wrenches 42 (Fig. 2) are mounted on the bottom plate 46
of the mast 22. As is known in the art, the deck wrenches 42
selectively engage a drill pipe section to facilitate
disconnection of two sections. The blasthole drill 10 as thus
far described is conventional and will not be described in
greater detail.
The blasthole drill 10 also comprises (see Fig. 2) four
drill-through pipe racks 50, 54, 58 and 62. It should be
understood that any number of pipe-racks can be employed. The
pipe racks 50, 54, 58 and 62 are selectively operable as
described below to move drill pipe sections from a stored
position to a position on the drill hole axis 30 or over the
drill hole. The pipe racks are shown in their stored positions
in Fig. 2. When the mast 22 is in its vertical position, each
pipe rack moves in a vertical plane including the drill hole axis
30. The pipe racks 50, 54, 58 and 62 are substantially
identical, and only the pipe rack 54 will be described in detail.
Common elements have been given the same reference numerals.
The pipe rack 54 includes (see Figs. 3-5) an upper arm
66 having inner and outer ends. The inner end is connected to
the mast 22 for pivotal movement relative thereto about a
generally horizontal axis 70. The upper arm 66 is moveable
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relative to the mast 22 between a generally vertical position
(Figs. 3 and 4) and a generally horizontal position (Fig. 5).
The pipe rack 54 also includes a lower arm 74 having inner and
outer ends. The inner end of the lower arm 74 is connected to
the mast 22 for pivotal movement relative thereto about a
generally horizontal axis 78. The lower arm 74 is moveable
between a generally vertical position (Figs. 3 and 4) and a
generally horizontal position (Fig. 5).
The pipe rack 54 also includes an elongated rack member
82 having upper and lower ends and having a longitudinal axis
generally parallel to the drill hole axis 30. The upper end of
the rack member 82 has thereon a clevis 86, and the outer end of
the upper arm 66 is connected to the upper end of the clevis 86
for pivotal movement relative thereto about a generally
horizontal axis 90. Thus, the outer end of the upper arm 66 is
pivotally connected to the rack member 82. The lower end of the
rack member 82 is connected to the outer end of the lower arm 74
for pivotal movement relative thereto about a generally
horizontal axis 94. The mast 22, the upper and lower arms 66 and
74 and the rack member 82 define a parallelogram. As is apparent
from Figs. 4 and 5, pivotal movement of the lower arm 74 from its
vertical position to its horizontal position moves the upper arm
66 from its vertical position to its horizontal position and
moves the rack member 82 horizontally and downwardly while
maintaining the rack member 82 generally parallel to the drill
hole axis 30 (i.e., vertical when the mast 22 is vertical). The
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lower arm 74 is moved between its vertical and horizontal
positions by a hydraulic assembly 98 connected between the lower
arm 74 and the bottom plate 46 of the mast 22. The upper end of
the hydraulic assembly 98 is pivotally connected to the lower arm
74, and the lower end of the hydraulic assembly 98 is pivotally
connected to the mast 22. Accordingly, the hydraulic assembly 98
moves the rack member 82 relative to the mast 22 and between an
extended position (Fig. 5) and a retracted position (Fig. 4).
This movement is in a plane including the drill hole axis 30 and
is horizontal when the mast 22 is vertical. Referring to Fig. 2,
it can be seen that the pipe racks 50, 54, 58 and 62 are
angularly spaced such that the respective rack members 82 move in
angularly spaced planes including the drill hole axis 30.
A lower support 102 (Figs. 2 and 5) is mounted on the
mast bottom plate 46 and provides vertical and horizontal support
for the lower arm 74 when the lower arm 74 is in its horizontal
position. As best shown in Fig. 5, the lower support 102
includes a projection 106 which extends inside the lower arm 74
to provide horizontal support.
The pipe rack 54 also includes (see Figs. 5 and 10-13)
a lower gate 110 mounted on the rack member 82 adjacent the lower
end thereof. The lower gate 110 includes (see Figs. 10-13) an
inner gate portion 114 fixed relative to the rack member 82. The
inner gate portion 114 has (see Figs. 11 and 12) a generally
semi-cylindrical inner surface 118. A semi-cylindrical insert
122 is mounted on the inner surface 118. The lower gate 110 also
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includes an outer gate portion 126 selectively moveable relative
to the inner gate portion 114 about a generally vertical axis 127
and between open (Fig. 12) and closed (Fig. 11) positions. The
outer gate portion 126 has a generally semi-cylindrical inner
surface 128. A semi-cylindrical insert 132 is mounted on the
inner surface. The inner surface of the inserts 122 and 132
define a generally cylindrical surface adapted to surround a
drill pipe 38 tas shown in Fig. 11) when the outer gate portion
126 is in its closed position. The size of the inserts 122 and
132 can be varied to accommodate pipes of different sizes. The
outer gate portion 126 also includes a generally horizontal shelf
136 (Fig. 12) which supports the lower end of a drill pipe 38
when the outer gate portion 126 is in its closed position. When
the outer gate portion 126 moves to its open position, the shelf
136 moves out from beneath the drill pipe 38 such that the drill
pipe 38 can move downwardly relative to the lower gate 110. If
the mast 22 is angled, the drill pipe 38 continues to be
supported by the inner gate portion 114 so that the inner gate
portion 114 maintains the drill pipe 38 on the drill hole axis
30. Also, when the outer gate portion 126 is in its open
position, the outer gate portion 126 is positioned to allow
movement of the lower gate 110 away from a drill pipe 38
previously supported by the lower gate 110.
The outer gate portion 126 is moved between its open
and closed positions by a hydraulic assembly 140 extending
between the inner gate portion 114 and the outer gate portion
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2150997
126. A latch 144 pivotally mounted on the inner gate portion 114
is moveable between latching (Fig. 11) and non-latching (Fig. 12)
positions. The latch 144 secures the outer gate portion 126 in
its closed position when the latch 144 is in its latching
position. A second hydraulic assembly 148 extending between the
latch 144 and the inner gate portion 114 moves the latch 144 and
secures the latch 144 in its latching position when the outer
gate portion 126 is in its closed position. The hydraulic
assemblies 140 and 148 are operably connected such that the
hydraulic assembly 148 will not allow the latch 144 to move from
its latching position unless the hydraulic assembly 140 is
actuated to move the outer gate portion 126 from its closed
position. This prevents accidental opening of the lower gate
110 .
The lower gate 110 also includes a pawl mechanism for
engaging a drill pipe 38 to prevent rotation of the drill pipe 38
in one direction when the outer gate portion 126 is in its closed
position. The pawl mechanism includes (see Fig. 13) a pawl 152
pivotally mounted on the inner gate portion 114 and a pawl 156
pivotally mounted on the outer gate portion 126. The pawls are
biased inwardly by springs 160.
The pipe rack 54 also includes (see Figs. 4-9) an upper
gate 164 mounted on the rack member 82 adjacent the upper end
thereof. The upper gate 164 includes (see Figs. 6-9) an upper
support arm 168 selectively moveable relative to the rack member
82 between an open position (Fig. 9) and a closed position (Figs.
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6-8). As best shown in Fig. 7, the upper support arm 168 is
arcuate and is pivotable relative to the rack member 82 about a
generally horizontal axis 172. The upper support arm 168
cooperates with a support member 176 (Fig. 7) extending from the
rack member 82 to secure a drill pipe 38 relative to the rack
member 82 when the upper support arm 168 is in its closed
position. A block 180 on the arm engages the pipe 38. The size
of the block 18Q can be varied to accommodate pipes of different
sizes. When the upper support arm 168 is in its open position,
the upper support arm 168 allows movement of a drill pipe 38 away
from the rack member 82. Conversely, the rack member 82 is
moveable away from a drill pipe 38 previously supported by the
upper gate 164 when the upper support arm 168 is in its open
position. A hydraulic assembly 184 extending between the rack
member 82 and the upper support arm 168 moves the upper support
arm 168 between its open and closed positions.
To operate the pipe rack 54 with a bit and stabilizer
(not shown) secured by the deck wrenches 42, the hydraulic
assembly 98 is actuated to move the rack member 82 to its
extended position (Fig. 5) in which the lower arm 74 rests on the
support 102. With the rack member 82 over the drill hole, the
rotary head 34 is lowered and screwed onto the top joint of the
drill pipe 38. After this joint is made, the upper and lower
gates are simultaneously opened by the hydraulic assemblies 140
and 184. After the gates are opened, the rotary head 34 and
attached drill pipe 38 are lowered and the lower end of the drill
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pipe 38 is attached to the stabilizer held by the deck wrenches
42. With this joint connection complete, the deck wrenches 42
retract and the rotary head 34 and drill pipe 38 can be further
lowered. The rotary head 34 can continue to move downwardly
until the rotary head 34 reaches the top of the pipe rack 54. In
other words, it is not necessary to retract the rack member 82
until the rotary head 34 reaches the top of the pipe rack 54.
Consequently, if the drill pipe 38 is taller than the pipe rack
54, as illustrated in Fig. 5, drilling can begin before the pipe
rack 54 is retracted. This saves a great amount of time because
the operator does not have to wait for the pipe rack 54 to clear
the pipe 38 before beginning drilling. It should be understood
that the drill pipe 38 can be two times as tall as the pipe rack
54 or rack member 82. The upper end of the pipe 38 preferably
rests against a support (not shown) on the mast 22 when the rack
member 82 is retracted.
The pipe rack 54 can be retracted anytime after the
drill pipe 38 is connected to the stabilizer. As the rack clears
the drill pipe 38, the upper and lower gates are closed. Once
the gates are closed a limit switch (not shown) trips and
activates a light (not shown) in the operator's cab indicating
that the gates are closed. Also, a limit switch (not shown) in
the mast 22 trips and signals the operator when the pipe 38 is
stored and secured.
To remove the drill pipe 38, the lower joint connection
is brought up to the deck and secured with the deck wrenches 42.
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The pipe rack 54 is extended with the gates opened. Next, the
lower joint is broken loose with the rotary head 34, and then the
rotary head 34 is raised until the bottom of the drill pipe 38 is
slightly above the shelf 136 of the lower gate 110. The gates
are then closed. When the lower gate 110 closes, the pipe flutes
(not shown) are in position with the pawls 152 and 156 to break
the joint loose from the rotary head 34. After the rotary head
34 is disconnected from the top of the pipe, the rotary head 34
is raised enough to clear the drill pipe 38 for retracting the
pipe rack 54 to the stored position. Once the pipe rack 54 is
stored, a limit switch trips and a light in the operator's cab
indicates that the rack is secured.
The pipe rack 54 moves "over center" as it moves to its
stored position. Although this is illustrated in Figs. 3-5, it
is exaggerated in Fig. 14 for clarity. When the mast 22 is in
the vertical position, as shown in Fig. 14, the inner axis 78 of
the lower arm 74 defines a vertical plane 200. When the mast 22
is in the vertical position and the rack member 82 moves from the
extended position to the retracted position (clockwise in Fig.
14), the outer axis 94 of the lower arm 74 moves through the
vertical plane 200. As a result, when the rack member 82 is in
the retracted position, gravity biases the rack member 82
clockwise or away from the extended position. Therefore, if the
hydraulic assembly 98 should unexpectedly fail while the rack
member 82 is in the retracted position, the rack member 82 will
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not "fall" or move to the extended position under the force of
gravity. This protects both personnel and equipment.
Various features of the invention are set forth in the
following claims.
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