U.S. patent number 3,893,520 [Application Number 05/435,196] was granted by the patent office on 1975-07-08 for canopy assembly for a dual boom drill.
This patent grant is currently assigned to FMC Corporation. Invention is credited to Thomas W. McCormick.
United States Patent |
3,893,520 |
McCormick |
July 8, 1975 |
Canopy assembly for a dual boom drill
Abstract
A portable drilling machine has a forwardly extending horizontal
platform upon which is pivotally mounted a pair of spaced forwardly
extending frames. The frames are arranged on the horizontal
platform to pivot toward and away from each other in a horizontal
plane. Each frame carries a boom assembly having front end and rear
end portions. The boom assembly front end portion supports a drill
unit. The boom assembly is operable to raise the drill unit in a
linear vertical path while the frame is arranged to move the boom
assembly and the drill unit in a horizontal plane. A canopy
assembly having front end and rear end portions is positioned in
overlying relationship with the frame and boom assembly and
includes a portion covered with an expanded metal screen positioned
adjacent the drill unit. The front end portion is pivotally
connected to an extensible rod that is concentrically positioned
within a lift cylinder rigidly mounted to the frame. Actuation of
the lift cylinder extends the rod vertically upwardly to move the
front end portion in a vertical plane. The rear end portion is
rotatably mounted to the frame and is operable upon actuation of
the lift cylinder to move longitudinally in a linear horizontal
path on the frame to permit linear vertical movement of the front
end portion. With this arrangement, the canopy assembly is moved in
a linear vertical path to a preselected height above the portable
drilling machine and protects the drill operator during the
drilling operation.
Inventors: |
McCormick; Thomas W.
(Morgantown, WV) |
Assignee: |
FMC Corporation (Fairmont,
WV)
|
Family
ID: |
23727422 |
Appl.
No.: |
05/435,196 |
Filed: |
January 21, 1974 |
Current U.S.
Class: |
173/34; 173/193;
173/37; 175/219 |
Current CPC
Class: |
E21B
7/026 (20130101); E21D 19/00 (20130101) |
Current International
Class: |
E21B
7/02 (20060101); E21c 011/02 () |
Field of
Search: |
;173/34,37,43,44,38,23
;299/11 ;175/219 ;61/45D |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; David H.
Attorney, Agent or Firm: Price, Jr.; Stanley J.
Claims
I claim:
1. A canopy for a dual boom drill comprising,
a mobile body having a horizontal platform,
drill means,
a forwardly extending frame pivotally mounted to said horizontal
platform,
a boom assembly having front end and rear end portions, said boom
assembly rear end portion pivotally secured to said forwardly
extending frame to permit movement of said drill means supported by
said boom assembly front end portion in a vertical plane,
a canopy assembly having front end and rear end portions maintained
in overlying relationship with said forwardly extending frame,
extensible means for moving said canopy assembly front end portion
in a linear vertical path to a preselected height above said frame,
and
articulating means for connecting said canopy assembly rear end
portion to said forwardly extending frame.
2. A canopy for a dual boom drill as set forth in claim 1 which
includes,
said articulating means operable to move said canopy assembly rear
end portion longitudinally in a horizontal path parallel to the
horizontal plane of said forwardly extending frame.
3. A canopy for a dual boom drill as set forth in claim 1 which
includes,
said canopy assembly rear end portion movably supported on said
forwardly extending frame for longitudinal movement in a horizontal
path upon extension of said extensible means.
4. A canopy for a dual boom drill as set forth in claim 1 which
includes,
said articulating means operable to move said canopy assembly rear
end portion longitudinally in a linear horizontal path parallel to
the horizontal plane of said frame and thereby permit said
extensible means to move said canopy assembly front end portion in
a linear vertical path.
5. A canopy for a dual boom drill as set forth in claim 1 in
which,
said canopy assembly front end portion is pivotally connected to
said extensible means.
6. A canopy for a dual boom drill as set forth in claim 1 which
includes,
said canopy assembly front end portion having an integral laterally
extending side portion adjacent said front end portion with an
expanded metal screen secured in overlying relation with said side
portion adjacent to said drill means.
7. A canopy for a dual boom drill as set forth in claim 1 which
includes,
ground stabilizing means for forcibly maintaining said frame
immovable relative to said mobile car, said stabilizing means
suitably mounted to said frame.
8. A canopy for a dual boom drill as set forth in claim 1 in
which,
said frame includes a pair of vertical sidewalls, each of said
vertical sidewalls having an upper edge portion,
said articulating means includes a roller positioned for
rectilinear rotational movement in a plane parallel to the
longitudinal axis of said frame on said upper edge portion,
channel means for maintaining said roller rotatably engaged to said
upper edge portion,
a pair of parallel spaced arm members connected to said canopy
assembly rear end portion and extending rearwardly therefrom,
a bore extending transversely through each of said arm members,
a shaft member coaxially secured to said roller and projecting
outwardly therefrom, said shaft member arranged to extend through
said bore, and
fastening means for securing said arm member to said shaft member
of said roller.
9. A canopy for a dual boom drill as set forth in claim 1 which
includes,
a pair of forwardly extending frames pivotally mounted in spaced
relation to and extending forwardly from said horizontal
platform,
said frames pivotally arranged on said horizontal platform to move
toward and away from each other, and
said canopy assembly suitably connected to each of said frames so
that said canopy assembly pivots in a horizontal plane with said
frame.
10. A canopy for a dual boom drill as set forth in claim 1 in
which,
said extensible means includes adjustable means for maintaining
said canopy assembly front end portion at a preselected vertical
height above said frame.
11. A canopy for a dual boom drill as set forth in claim 10 in
which said adjustable means includes,
a pair of outer cylinders mounted in spaced vertical relation to
said frame, each of said outer cylinders having a chamber
therein,
an inner cylinder concentrically arranged in each of said outer
cylinder chambers, said inner cylinder having a chamber
therein,
a rod member movably positioned in said inner cylinder chamber and
having an upper end portion extending outwardly therefrom, and
connecting means for pivotally securing said rod member upper end
portion to said canopy assembly front end portion to thereby permit
said rod member to move said canopy assembly front end portion in a
linear vertical path.
12. A canopy for a dual boom drill as set forth in claim 11 which
includes,
a plurality of vertically spaced bores passing transversely through
said rod member,
said inner cylinder having a transverse bore passing therethrough,
and
a pin member extending through said inner cylinder bore aligned
with said rod bore to thereby retain said canopy assembly front end
portion at a preselected vertical height above said frame.
Description
BACKGROUND OF THE INVENTION
1. field of the Invention
This invention relates to a canopy assembly for a mobile dual boom
drill, and more particularly to a canopy assembly arranged to move
in a linear vertical path to a preselected height above a mobile
drilling machine to support a section of the mine roof during the
drilling operation.
2. Description of the Prior Art
In underground mining, conventional roof bolts are employed to
support the roof of the mined area. In addition, transverse timbers
are retained in abutting relation with the roof surface to provide
support therefor and are held in place by roof bolts extending
through the timbers and engaged engaged the rock strata. The roof
bolts extend through predrilled holes in the mine roof and function
to prevent sliding movement of the different rock strata relative
to each other. The roof bolts stabilize the mine roof condition and
reduce the possibility of collapse of a portion of the mine roof
resulting in injury to operating personnel and damage to the mining
equipment.
Prior to engaging the bolts to the mine roof surface vertical holes
must be drilled to a predetermined depth into the roof. U.S. Pat.
Nos. 3,319,727 and 3,375,880 disclose portable drilling machines
which include a drill unit carried by a boom member that extends
forwardly from a mobile car. The boom member is supported by a
frame which is pivotally mounted to the horizontal platform of the
mobile car. Suitable linkage mechanisms are provided to move the
drill unit in a linear vertical path and an angular vertical path.
The frame pivotally mounted to the mobile car is provided with a
linkage mechanism which permits the frame and the boom to pivot in
a horizontal plane while the drill unit traverses a linear path
perpendicular to the longitudinal axis of the drilling machine.
Further linkage mechanisms are provided to move the drive unit
along a linear path in a horizontal plane parallel to the
longitudinal axis of the boom. With this arrangement, the drill
units are operable to drill bolt holes along lines transverse and
parallel to the longitudinal axis of the mobile car.
During the bolt drilling operations and prior to the placement of
the roof bolts and transverse timbers to support the roof, the roof
is unsupported presenting an unstable condition and a safety hazard
to workmen. Consequently, stress present in the overhead strata may
result in movement of portions of the roof and a roof fall. There
is need for a canopy that is maintained in overlying relationship
with the frame and boom of a portable mining machine and may be
moved therewith to protect the drill operator during the drilling
operations. The canopy assembly must be connected on the frame in
such a manner that the canopy is able to move horizontally in a
plane parallel to the longitudinal axis of the mobile car.
Furthermore, the canopy assembly must be adapted to be movable in a
linear vertical path for use in mines having roof portions of
different vertical height.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a canopy
for a dual boom drill which includes a mobile car having a
horizontal platform. A forwardly extending frame is pivotally
mounted to the horizontal platform. A boom assembly having front
and rear end portions is pivotally secured to the forwardly
extending frame to permit movement of drill means supported by the
boom assembly front end portion in a vertical plane. A canopy
assembly having front and rear end portions is maintained in
overlying relationship with the boom assembly. Extensible means are
provided for moving the canopy connecting front end portion in a
linear vertical plane to a preselected height above the frame.
Articulated means are provided for the the canopy assembly rear end
portion to the forwardly extending frame. The canopy assembly front
end portion is arranged to pivot about the extensible means and
move in a linear vertical plane.
The articulating means include a roller rotatably mounted to the
upper edge portion of each of the vertical sidewalls of the frame.
Channel means retain the roller on the upper edge portion and
permit the roller to tranverse a linear horizontal path thereon.
The roller is connected to a side arm which projects rearwardly
from the rear end portion of the canopy assembly. As the roller
traverses the surface of the upper edge portion of the vertical
sidewalls, the arm member moves in a path horizontal path parallel
to the horizontal plane of the frame.
With the above arrangement actuation of the extensible means to
vertically raise the canopy assembly front end portion moves the
roller in a linear horizontal path on the upper edge portion. The
rectilinear movement of the roller moves the canopy assembly rear
end portion connected to the arm member in a horizontal path
parallel to the horizontal plane of the frame. The horizontal
movement of the rear end portion urges the canopy assembly front
end portion to pivot about its connection to the extensible means.
Thus, the canopy assembly front end portion is moved in a linear
vertical path to engage in abutting relation the mine roof surface
or to a position adjacent thereof.
Accordingly, the principal object of this invention is to provide a
canopy assembly for a dual boom drill arranged to move in a linear
vertical path to a preselected height above the mobile drilling
machine to protect the drill operator during drilling
operations.
Another object of this invention is to provide a mobile drilling
machine with an overhead canopy assembly having a front end portion
capable of being raised in a linear vertical path to a preselected
height above the mobile drilling machine.
These and other objects and advantages of this invention will be
more completely disclosed and described in the following
specification, the accompanying drawings and the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a mobile drilling machine,
illustrating a pair of canopy and drill boom assemblies mounted on
the mobile drilling machine.
FIG. 2 is a fragmentary view in side elevation of the canopy
assembly illustrating in phantom the linear vertical movement
thereof relative to the boom assembly.
FIG. 3 is a sectional view taken along the line III--III of FIG. 2,
illustrating the pivotal connection between the front end portion
of the canopy assembly and the extensible rod of the canopy
cylinder.
FIG. 4 is a sectional view taken along the line IV--IV of FIG. 2,
illustrating the articulated connection between the forwardly
extending frame and the rear end portion of the canopy
assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, and particularly FIGS. 1 and 2, there is
illustrated a mobile drilling machine generally designated by the
numeral 10 that includes a body portion 12 having a horizontal
platform 14 positioned at the front portion thereof. A pair of
frames 16 are pivotally mounted to the horizontal platform 14 and
extend forwardly therefrom. A boom assembly, generally designated
by the numeral 18, includes a front end portion 20 and a rear end
portion 22 pivotally secured to the forwardly extending frame 16.
The front end portion 20 carries a drill unit 24 having a drill
steel mounted therein. A drill bit is secured to the end of the
drill steel and a hydraulic motor 26 rotates the drill steel and
drill bit.
A canopy assembly, generally designated by the numeral 28, is
positioned in overlying relationship with the frame 16 and the boom
assembly 18. The canopy assembly 28 includes a front end portion 30
and the rear end portion 32 which is secured to the frame 16 by
means described hereinbelow. The front end portion 30 includes a
laterally extending side portion 33 positioned adjacent the drill
unit 24. An expanded metal screen 34 is secured to the top surface
of the side portion 33.
A pair of motors 36 are mounted on the mobile body 12 and activate
a pair of hydraulic pumps 38 and a pair of vacuum pumps 40 mounted
on the mobile body 12. The drill unit 24 is connected to the vacuum
pump 40 by a hose (not shown). A dust collector 42 is secured to
each of the frames 16 and is connected by a hose (not shown) to the
vacuum pump 40 so that dust generated during the drilling
operations is drawn from the bit of the drill unit 24 through a
hose to the dust collector 42 by the vacuum pump 40.
Fluid under pressure is supplied by the hydraulic pumps 38 and is
fed through lines (not shown) to the hydraulic motors 44 mounted on
each side of the mobile body 12. The hydraulic motor 44 is
connected by gearing in a speed reducer housing 46 to the sprocket
48. The sprockets 48 carry chains that drive sprockets 50 on the
front wheels 52. The front wheels 52 are mounted on shafts 54
suitably secured to the front portion of the mobile body 12
adjacent the horizontal platform 14. The rear wheels 56 are axially
supported by the shafts 58 mounted to the rear portion of the
mobile body 12. With the above described arrangement, the mobile
body 12 carrying the frames 16 and the boom assemblies 18 is
propelled along the floor of an underground mine to an area where
bolt holes are to be drilled in the mine roof.
As illustrated in FIG. 1, a plurality of parallel spaced channel
members 60 are rigidly secured to the platform 14. Each of the
channel members 60 extends from the rear end of the platform 14
toward the front end thereof. Rollers of a universl connecting
mechanism (not shown) secured to the bottom portion of the frame 16
adjacent the rear end portion 62 thereof are arranged to traverse
the channel members 60. Swing means (not shown) mounted on the
platform 14 are pivotally connected to the bottom portion of the
frame 16. The swing means permit limited lateral swinging motion of
the frame 16 relative to the platform 14 while providing continuous
support for the frame 16. With this arrangement, the drill unit 24
moves in a horizontal plane perpendicular to the longitudinal axis
of the mobile car 12.
A pair of stabilizing jacks 64 are oppositely mounted to the front
of the frame 16. The stabilizing jack 64 is actuated either
mechanically or hydraulically and includes a base portion 66
arranged to forcibly engage the mine floor 67 and thereby stabilize
the frame 16, as illustrated in FIG. 2. The effective length of the
jack 64 may be remotely controlled to maintain the frame 16 at an
angle to the longitudinal axis of the mobile car 12. A horizontally
positioned hydraulic cylinder 68 connects the rear end portion 62
of the frame 16 to a boom carriage 70 which supports the rear end
portion 22 of the boom assembly 18 as illustrated in FIG. 1. The
boom carriage 70 is suitably supported by the frame 16 and is
rotatably mounted thereon. Actuation of the hydraulic cylinder 68
moves the boom carriage 70 longitudinally along the frame 16. The
longitudinal movement of the boom carriage 70 relative to the frame
16 moves the drill unit 24 through the boom assembly 18. Thus, the
longitudinal range of the drill unit 24 to drill the holes in the
mine roof is increased.
An elevating link 71 is supported by the boom carriage 70 and is
pinned to a pair of parallel spaced boom arms 74. An elevating
mechanism 72 functions to raise and lower the elevating link 72
which, in turn, raises and lowers the boom assembly 18 in an
arcuate forward path to thereby move the boom arms 74
longitudinally and provide a resultant rectilinear motion of the
drill unit 24 in a linear vertical path. U.S. Pat. No. 3,375,880
completely describes the arrangement for moving the drill unit 24
in a linear vertical path, as summarized hereinabove.
The canopy assembly 28 has a pair of spaced parallel tubular side
members 76 connected by a tubular front member 78 and a tubular
back member 80. To provide the canopy assembly 28 with additional
structural strength, a transverse member 82 entends between the
tubular side members 76. A pair of diagonal members 84 are secured
at one end to the tubular side members 76 adjacent the front member
78 and at the other end to the intermediate section of the
transverse member 82. The side portion 33 projects outwardly from
the canopy assembly front end portion 20 with the frame front
member 78 forming a portion of the side portion. The side portion
33 includes a plurality of transverse members 86 and a longitudinal
support member 87 that provide strength and rigidity for the canopy
side portion 33. The expanded metal screen 34 is secured to the
upper surface of the side portion 33 to protect the drill operator
from the hazards of rocks dislodging from the mine roof as holes
are drilled in the roof.
A canopy lift cylinder 88, illustrated in FIGS. 2 and 3, is mounted
by a brace 90 to each of the stabilizing jacks 64 which is, in
turn, mounted by a brace 91 to the front of the frame 16. The lift
cylinder is positioned in underlying relationship to the tubular
side member 76 of the canopy assembly 28. The lift cylinder 88
includes an inner cylinder 92 concentrically positioned therein.
The inner cylinder 92 has a vertical chamber 94, and a rod member
96 is slidably positioned in the vertical chamber 94 for extension
outwardly therefrom. The canopy lift cylinder 88 can be actuated
either manually or hydraulically to extend and retract the rod
member 96.
the extension rod 96, as illustrated in FIG. 3, has a transverse
bore 98 passing through the upper end portion thereof. A sleeve 100
is concentrically retained in the bore 98. The tubular side member
76 includes a pair of downwardly depending ears 102, each having a
transverse bore 104 passing therethrough. The upper end portion of
the rod member 96 is pivotally connected to the tubular side member
76 by pin 106 positioned within the bores 104 aligned with the bore
98. A pair of cotter pins 108 retain the pin 106 within the aligned
bores 98 and 104 so that the upper end portion of the rod member 96
remains pivotally connected to the tubular side member 76 of the
canopy assembly 28.
The rod member 96 includes a plurality of vertically spaced bores
110 that pass transversely therethrough. The inner cylinder 92 is
provided with a single bore 112 passing transversely through the
upper end portion thereof adjacent the ears 102 of the tubular side
member 76. A pin member 114 is arranged to pass through the bore
112 aligned with a selected bore 110 of the rod member 96. The pin
114 connects the rod member 96 to the inner cylinder 92 and thereby
maintains the rod member 96 immovable within the vertical chamber
94 of the inner cylinder 92. As illustrated in FIGS. 2 and 3, the
rod member 96 is maintained at its lowermost position within the
inner cylinder 92. By manually or hydraulically extending the rod
member 96 out of the inner cylinder 92 and aligning the bore 112
with a selected bore 110 and passing the pin member 114
therethrough, the rod member 96 can be maintained at a preselected
height above the frame 16. As illustrated by the phantom lines in
FIG. 2, the adjustable feature of selectively positioning the rod
member 96 in the inner cylinder 92 permits raising of the canopy
assembly 28 to a desired elevation depending on the height of the
mine roof.
The frame 16 includes a pair of oppositely positioned vertical
sidewalls 116, one of which is shown in FIG. 2. The sidewall 116 is
provided with an upper edge portion 118 as illustrated in FIGS. 2
and 4. The edge portion 118 extends horizontally outwardly from the
sidewall 116, and gusset 120 maintains the edge portion 118 in a
substantially horizontal plane relative to the sidewall 116. A
channel member, generally designated by the numeral 122, is
positioned on the frame 16 adjacent the canopy assembly tubular
member 80.
The channel member 122 includes a lower end portion 124 rigidly
secured in abutting relation to the inboard side of the sidewall
116. A horizontally extending lower abutment member 126 of the
channel member 122 is secured in abutting relation to the top of
the edge portion 118. A horizontally extending upper abutment
member 128 of the channel member 122 is arranged parallel to the
lower abutment member 126 and extends beyond the end of the lower
abutment member 126. With this arrangement, the upper and lower
abutment members 126 and 128 form an open end portion of the
channel member 122 for receiving a roller 130.
The roller 130 is mounted for horizontal, longitudinal movement on
the edge portion 118. The upper abutment member 128 projects over a
portion of the roller 130 and thereby aids to maintain the roller
130 within the open end portion of the channel member 122 as the
canopy assembly 28 is raised and lowered by operation of the lift
cylinder 88.
The roller 130 includes a bushing 132 and a threaded shaft member
134 coaxially aligned with the roller 130 projects outwardly from
the bushing 132. A pair of parallel spaced arm members 136 suitably
secured to the tubular member 80 of the canopy assembly rear end
portion 32 project rearwardly therefrom. Each of the arm members
136 includes a bore 138 that passes transversely through the end of
the arm member. The shaft member 134 of the roller 130 is arranged
to extend through the bore 138 of the arm member 136. A suitable
fastening device 140 is threadedly engaged to retain the arm member
136 on the shaft member 134.
The fastening device 140 exerts an inwardly directed force upon the
arm member 136 which is transmitted through the arm member to the
roller 130. Thus, the roller 130 is urged into abutting contact
with the lower abutment member 126. The above described articulated
connection between the canopy assembly rear end portion 32 and the
frame 16 permits the roller 130 to rotatably traverse the surface
of the horizontal edge portion 118 and thereby provide longitudinal
movement of the arm member 136 in a horizontal path parallel to the
horizontal plane of the frame 16.
The canopy assembly 28 is shown in phantom lines in FIG. 2 at its
uppermost elevation. As described hereinabove, the canopy assembly
28 is extended from its lowermost position to a preselected
position, within the range of vertical movement of the rod member
96 in the chamber 94, by removing the pin 114 from the aligned
bores 110 and 112 of the rod member 96 and the inner cylinder 92.
The rod member 96 is then freely movable in the chamber 94 for
extension outwardly from the inner cylinder 92. As the rod member
96 moves upwardly in a vertical plane, the roller 130 advances
forwardly on the edge portion 118. For an extension of the rod
member 96 from its lowermost position to its uppermost position,
the axis 142 of the roller 130 traverses the distance 144 on the
edge portion 118. Thus, the vertical movement of the rod member 96
in the chamber 94 provides horizontal movement of the roller 130 on
the edge portion 118. For a selected position of the rod member 96
intermediate of its upper and lower positions, the axis 142 of the
roller 130 will move longitudinally on the edge portion 118 within
the distance 144.
The articulation between the roller 130 and the arm member 136
permits the arm member 136 to move in a linear horizontal path
parallel to the horizontal plane of the frame 16 as the roller 130
traverses the surface of the edge portion 118. The canopy assembly
rear portion 32 connected to the arm member 136 through the back
member 80 follows the path traversed by the arm member 136 which is
determined by the travel of the rollers 130 on the edge portions
118. The horizontal movement of the arm members 136 and the rear
end portion 32 urges the canopy assembly front end portion 30 to
pivot about the connection of the ears 106 to the rod members 96.
Thus, the combined horizontal movement of the canopy assembly rear
end portion 32 and the pivotal movement of the canopy assembly
front end portion 30 about the rod member 96 provides a resultant
linear vertical movement of the front end portion 30.
The front end section 30, in its lowermost position relative to the
frame 16 as illustrated in FIG. 2, is inclined downwardly at an
angle from a horizontal plane passing through the pivotal
connection of the front end portion 30 to the rod member 96.
Extension of the rod member 96 vertically outwardly from the
chamber 94, pivots the front end portion 30 about the pin 106 to
approach a substantially horizontal position, as indicated in
phantom. With this arrangement, the pivotal movement of the front
end portion 30 upwardly in a horizontal plane and the articulation
of the rear end portion 32 about the frame 16 in a linear
horizontal path moves the front end portion 30 in a linear vertical
path as the rod member 96 moves vertically upwardly.
In operation, the mobile drilling machine 10 with the combined boom
assemblies 18 and frames 16 extending forwardly from the horizontal
platform 14 is moved into position for drilling at a desired area
in the mine. The frames 16 are then selectively pivoted toward or
away from each other on the horizontal platform 14 to move the
respective drill units 24 secured to the ends of boom assemblies 18
into the desired horizontal position. The stabilizing jacks 64 are
actuated to urge the base portions 66 into abutting contact with
the mine floor 67 to thereby fixedly secure the frames 16. The
hydraulic cylinder 68 is actuated to move the boom carriage 70 and
the boom assembly 18 longitudinally on the frame 16 while the drill
unit 24 is spaced from the roof. The linkage mechanism for the boom
assembly 18 is then actuated to move the drill unit 24 vertically
upwardly into drilling position. Simultaneously with the vertical
movement of the drill unit 24, the canopy assembly front end
portion 30 is raised in a linear vertical path by extension of the
rod member 96 from the inner cylinder 92 to provide working space
from the drill operator beneath the canopy side portion 33.
The canopy front end portion 30 may also be moved into abutting
contact with the mine roof surface to thereby support the mine roof
during the drilling operation. The drilling operation is then
commenced by actuation of the motor 26 to rotate the drill bit.
Should rock dislodge from an unsupported section of the mine roof
during the drilling operation, the machine operator controlling the
drill unit 24 is protected from personal injury by the expanded
metal screen 34 covering the side portion 33 of the canopy assembly
28 positioned above him. The covered side portion 33 is
conveniently located adjacent the drill unit 24 to permit the
operator to position himself below the covered side portion as he
controls the drill unit 24.
According to the provisions of the patent statutes, I have
explained the principle, preferred construction and mode of
operation of my invention and have illustrated and described what I
now consider to represent its best embodiments. However, I desire
to have it understood that, within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically illustrated and described.
* * * * *