Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1~3~80~;
CONVERTIBLE RAISED DRILL APPARATUS
Back round of the Invention
g
This invention relates to the support structure of
a raise drill apparatus and, in particular, to one which
combines the operational advantages of a cantilevered support
structure where the thrust and torque producing mechanisms
are supported by a column extending from a base which engages
the ground surface only on one side of the drill hole, with
one where the thrust and torque producing mechanisms are not
cantilevered and the base engages the ground surface on more
than just one side of the drill hole.
A raise drill is an apparatus which i9 used for
forming relatively large-diameter drill holes. This is done
by drilling a pilot hole downwardly through earth strata until
the drill bit emerges into an opening such as a mine entry.
The drill bit is replaced with a larger-diameter drilling
head, the machine operating to pull and rotate the head back
toward the ground surface along the pilot hole.
Machines of this type were traditionally designed
so that the thrust cylinders and drill pipe rotating mechanism
were supported on a ground engaging base which substantially
surrounded the drill hole. Normally a concrete pad is formed
on the ground surface with rock bolts projecting upwardly
for engaging and anchoring the base in place.
Because of the weight distribution around the hole
and short distance between the portion of the base which
engages the concrete pad and the drill hole, the entire
large-diameter hole could not be completed by the machine
because of the possibility that once the cutting head emerged
through the ground surfaoe the machine would fall into the
.,
,
-
80~;
--2--hole. Safe operational procedure required that when the
cutting head approached within several feet of the ground
surface the cutting head would have to be lowered and removed
or restrained and the machine moved. The hole would then be
completed by blasting or other techniques for removing the
remaining material.
Attempts to overcome this problem include a raise
drill apparatus where the thrust and torque producing hardware
is cantilevered from a support frame so that the support base
need only engage the supporting concrete pad on one side of
the drill pipe. In this way, the cutting head was able to
form the hole and be pulled all the way through the ground
surface without danger of the machine falling into the hole
because the base held in place by rock bolts embedded in the
concrete pad was spaced substantially away from the drill
pipe axis.
However, this cantilevered design caused other
problems. For example, reactive forces to the required torque
and thrust was of such a magnitude that additional supports
were found necessary in order to operate at maximum efficiency.
Without these additional supports, rock bolts normally used
to anchor the base of the machine to the concrete pad would
tend to loosen. It was found that the most effective type
of additional supports are hydraulic cylinders located between
designated portions of the machine and a mine roof when the
machine is located underground. Since there was no stable
upper surface for above-ground usages of the machine, such
supplemental supports were not available which sharply cur-
tailed the effectiveness of a machine with this design above-
ground. Further, the use of such supplemental supports, whenpossible, restrictsmachine access and requires additional
set-up time.
Summary of the Invention
The problems discussed above have been solved in
accordance with the invention by a raise drill apparatus
which has a cantilevered support structure, but which also
includes removable supplemental ground-engaging pads located
on the side of the drill pipe opposite the ground-engaging
portion of the base, which operate to absorb reactive torque
and thrust so that the advantages of the normal non-cantilevered
apparatus are provided during drllling. The supplemental
1~3'~806
pads can be removed when the cutting head approaches the
ground surface so that the hole can be completed by the cutting
head, Since a cantilevered design is used the danger of
the apparatus alling into the hole is eliminated.
The raise drill apparatus includes a ground-engaging
base and a support and guide column projecting from the base.
It is understood that the term "ground-engaging" encompasses
the base engaging a concrete support pad formed on the ground
surface for supporting the apparatus. A drill pipe engaging
and rotating mechanism is slidingly mounted on the support
and guide column and thrust means, such as hydraulic thrust
cylinders, are connected between the base and the drill pipe
engaging and rotating mechanism. Torque and axial thrust
are thus applied to the drill pipe for drilling the pilo~
hole and up-reaming the raised hole.
More specifically, the drill pipe engaging and rotating
mechanism may include a motor, a chuck and appropriate gear,
chain, or other drive connections between the two, the
entire mechanism being supported by and cantilevered from
the support and guide column, The base includes ground-
engaging pads located on the same side of the drill pipe as
the support and guide column. A supplemental ground-engaging
support section is connected to the guide column on the side
opposite the drill pipe for supporting the guide column,
rock bolts projecting from the concrete pad operate to anchor
the base and supplemental support section to the ground surface.
The base also includes an extension which projects to
the side of the drill pipe opposite the support and guide
column, a pair of supplemental ground-engaging pads being
3 -
cg/~'
~ -
.:
-
113~806
connected between the extended base portion and ground for
providing supplemental support during up-reaming. The
supplemental pads are removable so that the drill hole can
be completed by the cutting head.
In this way, during up-reaming operations the
additional support pads which can be anchored to the ground
surface with rock bolts for additional stability supply
additional support for the apparatus through downward force
against the ground reactive to the upward pull of the thrust
cylinders. In this way the machine can operate the cutting
head at full torque and thrust without the need for supplying
additional supports to the machine.
~;r~
..~'
- 3a -
cg//~f
'"
113~806
--4--
When the cutting head is pulled to the ~icinity of
the ground surface, the supplemental pads can be removed and
the cutting head used to comple~e the hole instead of having
to remove the entire machine as in prior art devices where a
non-cantilevered design is utilized. Since the drilling
mechanism is cantilevered from one side of the apparatus,
weight distribution and rock bolting are such that there is
no danger of the apparatus falling into the drill hole. Much
time is saved since normal up-reaming operations can be used
to complete a hole instead of having to lower the cutting head
and remove it from below, remove the equipment, and then
blast or chip the remaining material, or by having to restrain
the head by chains, etc., remove the machine, blast or chip
out the material and then remove the head.
Brief Description of the Drawings
These and other objects and advantages of the
invention will become apparent when the detailed description
of a preferred embodiment of the invention set forth below
is considered in conjunction with the accompanying drawings,
in which:
Figure 1 is a perspective view of a raise drill
apparatus constructed in accordance with the invention;
Figure 2 is a side plan view of the base portion
of the apparatus shown in Fig. l; and
1 25 Figure 3 is a front plan view of the base portion
of Fig. 2.
Detailed Description of a Preferred Embodiment
Referring now to Fig. 1, a raise drill 10 is shown
which includes a base generally designated by reference
numeral 12 which engages the ground surface at the rear of
the apparatus and supports a guide and support column 14
upon which a drill pipe turning mechanism 16 is mounted for
up and down movement. A pair of hydraulic thrust cylinders
18 are connected between the turning mechanism 16 and base
12 for supplying axial force to drill pipe engaged by the
turning mechanism. The turning mechanism 16 includes a
motor 20, chuck 22 and appropriate reduction gearing in
gear box 23 connecting the two.
For a machine of this type, relatively large-
diameter holes are formed by first drilling a pilot hole
113~80--5--
downwardly through earth strata by utilizing torque supplied
by the motor 20 and downward fsrce supplied by the thrust
cylinders 18. Additional lengths of drill pipe are added
as the hole progresses by using techniques well known in
S the prior art. When the cutting bit emerges into a mine entry-
way or other underground opening, the bit is removed and
replaced with a large-diameter cutting head. The combination
of torque with upward force will operate to form the large
raise bore along the path of the pilot hole, lengths o~ drill
pipe being removed as the hole progresses as is well known
in the prior art.
Traditionally, raise drill apparatuses were designed
with the base substantially surrounding the drill hole and
the weight of the apparatus distributed around the base.
However, as the cutting head approached the ground surface,
the cutting head would hav~ to be disconnected and the machine
moved from the vicinity of the hole so that the hole could
be completed either by blasting or by other methods. This
was done to eliminate the danger of the machine falling in
the hole.
A cantilevered-type raise drill apparatus such as
shown in Fig. 1 was developed to overcome these problems,
where the base 12 only engages the ground surface on one side
of the drill pipe. In order to provide the necessary support
for the torque and thrust producing hardware, a supplemental
support frame 24 is provided which is anchored by suitable rock
bolts and connected to the guide support column 14 through
pivot pins 28 and a turnbuckle mechanism 26 which is adjustable
for varying the angle of the guide support column 14 and accord-
ingly the angle of the raise hole.
As shown in Fig. 2, the guide and support column 14is rigidly connected to a worktable 32. The base 12 includes
a pair of rear support pads 30 which engage the ground sur-
face and support the weight of the apparatus 10. The work-
table 32 i5 connected to the pads 30 through the pivot pins28 so that the angle of the apparatus and accordingly the
drill hole can be selectively varied by adjusting the turn-
buckle 26. The thrust cylinders 18 are mounted on the work-
table 32, the piston rods of the thrust cylinders 18 being
connected through pins 34. The worktable includes a center
opening 36 through which the drill pipe (not shown) can
1~3~806
--6--
project, a recessed portion 38 being provided to accommodate
a fork member (not shown) for engaging indentations on the
outer surface of the drill pipe so that sections can be added
or removed from the drill pipe in a known way during the
pilot hole drilling and up-reaming operations.
As described above, for cantilevered machineæ of
this type, rock bolts ~not shown) are used to anchor the rear
pads 30 and the outer end of the supplemental support frame
24 to a supporting concrete pad (not shown) in order to absorb
reactive torque and thrust from the turning mechanism 16 and
cylinders 18. However, as mentioned above a supplemental
downward force had to be applied to the apparatus at full
torque and/or thrust to prevent the rock bolts from loosening.
The supplemental force is applied in accordance
with the invention by a pair of front supplemental support
pads 40, connected between the front of the worktable 32 and
the ground surface through turnbuckles 42, when the raise
hole is being formed. The turnbuckles 42 are provided for
adjusting the distance between the front pads 40 and the
worktable 32 to maintain contact with the ground when the
machine angle is varied by adjusting the turnbuckle 26. The
turnbuckles 42 are connected between the worktable 32 and
front pad 40 through pivot pins 46 and 48 to allow the relative
angular adjustment mentioned above. A pair of turnbuckles
44 are provided to connect the front pads 40 to the rear pads
30 for additional stability.
As mentioned above, the front pads 40 are installed
either during down-drilling to provide additional support for
high drilling force, or during up-reaming operations to
provide the additional support necessary for high thrust tor~ue
reaming. Anchor bolts (not shown) can be used to anchor the
front pads 40 to the ground. When the cutting head is within
several feet of the ground surface, the front pads 40 can
easily be removed by removing the pivot pins 46 and disconnect-
ing the turnbuckles 44 so that the cutting head can be usedat a lower tor~ue and thrust to complete the hole.
Since the base is located only on one side of the
drill pipe and anchored to the ground surface at a substantial
distance from the drill hole, the danger of the machine falling
in the hole is virtually eliminated so that the hole can be
completed by the cutting head. However, the disadvantages
.. .. . . ..
113L~806
--7--
of the cantilevered design are eliminated by providing the
supplemental pads 40 for additional support so that the hole
can be formed at maxim~m thrust and torque for optimum
efficiency. In this way, the advantages of the cantilevered
raised drill apparatus are combined with those of one where
the ground supporting base substantially surrounds the drill
hole, with the attendant disadvantages eliminated.
It should be kept in mind that improvements and
modifications can be made to the invention by one with
ordinary skill in the art and that all such improvements and
modifications are contemplated as coming within the scope
of the appended claims.
...... ,..... .. ~ .
