U.S. patent number 3,593,807 [Application Number 04/884,276] was granted by the patent office on 1971-07-20 for drilling apparatus.
Invention is credited to Frank J. Klima.
United States Patent |
3,593,807 |
Klima |
July 20, 1971 |
DRILLING APPARATUS
Abstract
A control system for hole-drilling equipment in which a rotary
drill bit and stem is rotated at a predetermined speed and the
downward force exerted upon the rotary drill bit is controlled in
accordance with a signal derived from the torque required to rotate
the drill stem at a constant speed and a signal proportional to a
desired drilling rate. Further signals proportional to the actual
drilling rate and the penetration rate of the drill stem may also
be utilized in relative adjustable combinations so as to provide
optimum efficiency of operation.
Inventors: |
Klima; Frank J. (Virginia,
MN) |
Family
ID: |
25384300 |
Appl.
No.: |
04/884,276 |
Filed: |
December 11, 1969 |
Current U.S.
Class: |
173/6;
175/27 |
Current CPC
Class: |
E21B
44/00 (20130101); E21B 44/04 (20130101) |
Current International
Class: |
E21B
44/00 (20060101); E21b 003/02 () |
Field of
Search: |
;173/6,9 ;175/27 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3373823 |
March 1968 |
Fullerton et al. |
|
Foreign Patent Documents
Primary Examiner: Purser; Ernest R.
Claims
Having now therefore fully illustrated and described my invention,
what I claim to be new and desire to protect by Letters Patent
is:
1. In apparatus of the class above described, the combination
comprising;
a. a drill stem slidably rotatably disposed on a mounting therefor,
said drill stem including drill means at one end thereof;
b. drive means, including speed controlling means, disposed on said
mounting and operatively connected to rotate said drill stem;
c. means connected to said drill stem and drive means for providing
a first signal proportional to the torque output thereof;
d. a second source of signal, said second source of signal being
adjustable;
e. first comparator means connected to said first and second
signals for providing a third signal proportional to the deviation
of said first signal from a predetermined value;
f. further drive means, including control means therefor, connected
to said drill stem to drive said drill stem along the axis slidably
disposed on said mounting; and
g. said control means including means for providing a fourth signal
proportional to the force exerted upon said drill stem by said
further drive means and means for controlling the energization of
said further drive means in accordance with said third and fourth
signals.
2. The apparatus of claim 1 in which the second signal is
proportionally related to the formation in which the drill stem is
operative.
3. The apparatus of claim 1 in which the fourth signal is of
substantially constant magnitude with respect to the first
signal.
4. The apparatus of claim 3 in which the first signal includes a
further signal proportional to the rate of motion of the drill stem
with respect to the longitudinal axis of the mounting.
5. The apparatus of claim 1 in which the first signal includes a
further signal proportional to the rate of motion of the drill stem
with respect to the longitudinal axis of the mounting.
6. The apparatus of claim 5 in which the second signal is
proportionally related to the formation in which the drill stem is
operative.
7. The apparatus of claim 5 in which the first signal is of
substantially constant magnitude.
8. The apparatus of claim 5 in which means are provided for
variably combining the first and further signal.
9. The apparatus of claim 8 in which the second signal is
proportionally related to the formation in which the drill stem is
operative.
10. The apparatus of claim 8 in which the first signal is of
substantially constant magnitude.
Description
This invention relates generally to automatic drilling apparatus
and is more particularly directed to automatic drilling apparatus
of the class wherein a rotary drilling bit is operatively
controlled so that its speed remains constant as determined by the
torque requirements for effecting such speed so as to control the
downward pressure upon the drill bit, such control may further
include other predetermined factors which may exist as dynamic
factors or which may be predetermined in accordance with known
experience and drilling factors.
The present invention contemplates the use of well-known portable
drilling apparatus which is normally supplied with a tower for
generally, vertically slidably receiving and rotatably disposing a
drill stem assembly having a drill bit at its lower end. A
controllable speed motor is adapted to supply the rotary motion and
suitable controllable means are provided for effecting a downward
pressure upon the drill stem and thence upon the drill bit.
Suitable means are provided for sensing the torque required to
maintain a constant speed of rotation of the drill stem. A signal
proportional to the torque is then compared with a further signal,
the magnitude of which may be selected on the basis of experience.
A comparison of the two signals provides a resultant signal which
is then utilized to control, through suitable motor drive means, a
downward pressure upon the drill stem so that the most efficient,
maximum drilling rate may be obtained through strata of various and
differing composition as might be encountered in drilling a hole
into the earth, for whatever reason desired.
It is therefore an object of my invention to provide drilling
apparatus of improved efficiency.
A further object of my invention is to provide drilling apparatus
having increased speed of operation.
Another object of my invention is to provide drilling apparatus
which automatically compensates for the encounterance of materials
of divergent characteristics.
These and other objects of my invention will become apparent from
the appended specification, claims and drawing in which the sole
FIGURE illustrates a schematic and diagrammatic representation of
drilling apparatus incorporating the principles of my
invention.
Referring now to the drawing, there is shown a drill rig 10
disposed on a surface 19 of the earth. Drill rig 10 includes a
vertically upwardly extending tower assembly 11 which rotatably and
vertically slidably supports a drill stem assembly 12 having a
drilling bit 13 affixed at its lower end. Drill stem 12 and drill
bit 13 are shown extending vertically downwardly through a
plurality of layers of materials of varying and divergent
composition as represented by reference characters 14, 15, 16, 17,
and 18. Such layers may consist, for example, of soft dirt, sand,
sandstone, limestone, taconite and the like and experience has
proven that such layers may generally be comprised of alternate
soft and hard material of varying degrees, each of which may be
penetrated by a suitable drill under appropriate circumstances, but
none of which present conditions under which one mode of operation
of drilling apparatus will efficiently, or even satisfactorily,
penetrate.
Shown schematically on the drawing is a rotary drive motor 20 which
may be disposed at the top end of tower 11 and is connected through
suitable drive means (not shown) to rotate the drill stem that is
rotatably, slidably disposed in tower 11. Associated with drive
motor 20 is a suitable means (also not shown) which supplies an
electrical signal proportional to the torque being supplied to
drive motor 20 and thence to drill stem 12 to rotate the same. Such
means might comprise a resistance in series with suitable
electrical connections for an electric drive motor, the current
being generally proportional to the torque required. The resistor
might be connected to suitable electrical utilization apparatus
shown in the form of an adjustable signal combiner 25, through a
connecting means 21.
A second motor, indicated by reference character 22 is shown in the
form of a hydraulic motor which is provided with a suitable drive
connection 23 to exert a downward force upon drill stem 12. A
suitable drive connection 23 might, for example, take the form of
chain members (not shown) which are pulled downwardly by the
rotation of hydraulic motor 22 to, in turn, exert a downward force
upon drill stem 12. Drill stem 12 is also provided with a suitable
means (not shown) for generating or providing a penetration rate
signal of drill stem 12 into the earth as it proceeds in its
intended drilling operation. Such a source may suitably be
connected at the upper end of tower 11 and in cooperation with
drill stem 12 to provide a signal (proportional to the rate of
descent of drill stem 12) that is connected to adjustable signal
combiner 25 through connecting means 24.
Signal combiner 25 is provided with a control knob 38 which may be
used to effectively proportionally combine the signals appearing on
conductors 21 and 24 to vary their relative effect upon the output
of signal combiner 25 which appears at conductor 27 that is in turn
connected to a first signal comparator 26. Signal comparator 26 is
also connected to an adjustable command signal source 28 having a
know 39 for providing a suitable reference signal.
Comparator 26 compares the signals comparing on conductors 27 and
29 and provides an output signal of polarity, or sense, and
magnitude proportional to the difference between the two signals
appearing at the inputs thereof. A second signal comparator 30 is
connected to the output of first signal comparator 26 through
conductor 31. Comparator 30 also has an input signal supplied by a
pressure transducer 32 that is connected in the hydraulic line
supplying hydraulic fluid under pressure to hydraulic motor 22.
Transducer 32 supplies an electrical signal through conductor 33 to
second signal comparator 30. A signal of suitable sense and
magnitude is supplied to a hydraulic control valve 34 through
signal connector 35. Hydraulic control valve 34 is operative in
response to the sense and magnitude of the signal to control the
fluid of hydraulic fluid under pressure from hydraulic pump 37 to
hydraulic motor 22 to thereby control the force applied in a
downward direction to drill stem 12. Hydraulic motor 22 is shown
connected to a suitable tank 36 through a hydraulic connection and
valve 34 is likewise shown connected to tank 36 through a suitable
hydraulic connection.
It is anticipated that the drill rig 10 might conveniently take the
form of a Bucyrus-Erie Company Model 60-R Blast Hole Drill to which
the principles of my invention may suitably be applied by those
skilled in the art. Rotary drive motor 20 might conveniently
incorporate the principles of the well-known Ward-Leonard Motor
Control System for effecting a predetermined constant rotational
speed as determined by the desires of an operator. Having the
principles of my invention in mind, the characteristics of
adjustable signal combiner 25 and adjustable command signal
generator 28 may suitably be determined by those skilled in the art
to which my invention pertains. Hence, no detailed presentation of
apparatus has been set forth nor has such apparatus been supplied
for first and second signal comparators 26 and 30, the penetration
rate signal appearing on conductor 24, pressure transducer 32 or
hydraulic servo valve 34. All of these components are readily
available to those skilled in the art and the exact nature of such
devices may vary from individual to individual and are best left to
the selection of the independent designer where he is familiar with
the operational characteristics of the apparatus.
OPERATION
In operation, drill rig 10 is disposed over the location at which
it has previously been determined, a hole is to be drilled into the
earth through surface 19. Motor 20 is energized to rotate at a
predetermined speed, nominally 60 r.p.m., although this may vary
dependent upon the experience and knowledge of the operator of the
strata through which the hole is to be drilled. Assuming that know
38 on first signal combiner 25 is positioned so as to eliminate any
effect from penetration rate signal 24, a signal proportional to
the torque required to rotate drill stem 12 appears at conductor 21
and thence through signal combiner 25 to conductor 27 connected to
first signal comparator 26. According to a predetermined value,
again, to some extent dependent upon the experience and knowledge
of the operator of the apparatus, knob 39 on adjustable command
signal source 28 is set at a predetermined value which affects the
level of signal applied through conductor 29 to the input of first
signal comparator 26.
The signals appearing at conductors 27 and 29 are compared to
provide an output signal at conductor 31 of a sense and magnitude
proportional to any difference appearing between the signal
proportional to the torque supplied by motor 20 and the signal
provided by adjustable command signal source 28.
This resultant signal is compared with the signal supplied by
pressure transducer 32 which supplies an electrical signal
proportional to the downward force exerted upon drill stem 12 by
motor 22 at conductor 33. This signal is compared with the signal
appearing at conductor 31 to provide a further resultant signal of
given sense and magnitude which causes servo valve 34 to operate in
such a manner as to increase or decrease the flow of hydraulic
fluid to motor 22 to increase or decrease the downward force upon
drill stem 12 as dictated by the sense of the resultant signal
determined in second comparator 30. A feedback path is indicated by
a dotted line extending from servo valve 34 to second comparator 30
to illustrate a simple well known feedback arrangement to suitably
control the operation of servo valve 34.
The operation of pump 37 and tank 36 in connection with suitable
hydraulic fittings supplied intermediate all of the hydraulic
components are believed straightforward and easily ascertainable by
one skilled in the art and hence have not been identified by
reference characters nor has the exact nature of the apparatus or
operation been described except in terms of function, since the
requirements may easily be fulfilled by the use of the illustrated
or other hydraulic components well known to those skilled in the
art.
In a further mode of operation, the effective combination of the
torque signal appearing at conductor 21 and the penetration rate
signal appearing at conductor 24 may be varied according to the
position of adjustment knob 38 on adjustable signal combiner
25.
* * * * *