IMPROVEMENTS IN ROCK DRILLING APPARATUS
Year: 1883

page_text: LETTERS PATENT to William Phillips Thompson of the Liverpool and London
Agency for Foreign Patent Solicitors 6 Lord Street Liverpool in the county
of Lancaster Civil Engineer for an Invention of "IMPROVEMENTS IN ROCK
DRILLING APPARATUS." a communication to him from abroad by George
McClellan Derby First Lieutenant, Corps of Engineers U.S.A, of Astoria
Queens County, State of New York, United States of America
PROVISIONAL SPECIFICATION left by the said William Phillips Thompson
at the Office of the Commissioners of Patents on the 5th June 1883,
WILLIAM PHILLIPS THOMPSON of the Liverpool and London Agency for
Foreign Patent Solicitors 6 Lord Street Liverpool in the County of Lancaster
Civil Engineer "IMPROVEMENTS IN ROCK DRILLING APPARATUS"-a communi-
cation to me from abroad by George McClellan Derby, First Lieutenant, Corps
of Engineers U.S.A., of Astoria, Queens County, State of New York, United
States of America.
This invention belongs to that class of drill denominated tubular, in which the
bit or cutting edge of the drill is formed upon or attached to the end of a tubular
steel, and by the action of which an annular section of the rock operated upon is
cut away. The advantage of this class is that the labor that would be expended
in pulverizing the interior is saved. It belongs also to the class known as
reciprocating, which are operated upon the principle of the steam hammer. These
have their shank connected to a piston working in a cylinder; steam or compressed
air being admitted alternately before and behind the piston, drives it rapidly to
and fro, causing the drill to strike the rock with great rapidity and force. The
advantage of the reciprocating drill, besides the rapidity of its operation, is that it
can be used to drill a hole at any angle to the vertical.
Heretofore, so far as my knowledge extends, it has not been found practicable
to operate a tubular drill with this class of machine, but only drills having a solid
steel and bit have been so worked. The diamond drill is tubular, but is always
worked by a constant revolution about the axis of the tube, and scratches away
the rock without striking.

page_text: The practical difficulties to be overcome in using a tubular bit in connection
with the reciprocating driver above described are, 1st, to dispose of the core formed,
and 2nd, to prevent the clogging of the drill by the accumulation of debris in the
hole. These difficulties are largely increased by the very high rate of speed at
which these machines are run, and the small diameter of the holes that it is
customary to drill with them.
The object of this invention is to overcome these difficulties, and to provide
means by which a tube may be employed for drilling holes under the influence
of a rapid to-and-fro motion, thus uniting the advantages of both classes of
machines.
The drilling machine constructed upon the principles of this invention may be
described as follows:-
A tubular bit is vibrated back and forth in any convenient manner, as for
example by attaching its shank to the piston rod of a reciprocating engine.
Surrounding this piston rod is a chamber supplied with steam, air, water, or other
suitable fluid agent under pressure, which is admitted to the interior of the rod,
shark, and drill (all three of which are provided with central bores) through an
opening made in the piston rod at some point which is at all times within said
chamber. The constant flow of the said fluid agent serves to force the powdered
rock away from the drill, and out through the drill hole as it is being formed,
thus preventing the drill from becoming clogged and overheated and
destroying the temper of the bit. The clearance way for the debris is provided
by giving to the cutting edge a peculiar form, which is one of the main features of
this invention.
SO
In manufacturing the drill it is preferred to begin by forming any convenient
number of transverse wedge-shaped teeth upon the end of a tube. The adjacent
teeth should meet each other at their respective bases, and the surplus metal
obtained by forming the triangular openings between them be thrown out upon
their lateral surfaces, thus causing the edge-end of any tooth to be of greater
width than its base. This method of treatment gives a polygonal form to the
tube when viewed endwise, as lines joining the outer ends of the cutting edges of
the teeth would form a regular figure, the number of sides of which would depend
upon the number of teeth.
The exact form given to the face of the drill in carrying out this invention will
depend largely both upon the size of the hole to be made, and the material to be
operated upon. If a large hole is to be made, it is important to have the core
remain unbroken, so that it can be removed in as large pieces or sections as
possible, thereby saving the power that would be necessary to pulverize it. Or if
the rock operated upon is very hard, then it again becomes important to leave the
core unbroken. To do this it is necessary that the teeth of the drill be pitched up
both on the inside and outside, that is the face of the teeth should extend beyond
the surface of the tubular steel both on the inside and on the outside. In such
cases the tubular steel must be nearly as long as the distance the machine feeds.
On the other band, if the hole to be drilled is small, or if the rock is soft and
easily pulverized, it is not always necessary to pitch up the inside of the teeth in
the manner described, the pitching up of the outside being sufficient. The drill
then by its action breaks off the core in small sections and soon pulverizes it, the
debris of which is carried away with the rest through the triangular spaces
between the teeth, which provide abundant clearance for such escape.
It is not a matter of necessity that the spaces between the teeth be triangular
or V-shaped. They may if desired be U-shaped, and may be extended upward
for some distance upon the outer face of the tubular bit by filing or otherwise.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Phillips Thompson in the Great Seal Patent Office on
the 4th December 1883.
WILLIAM PHILLIPS THOMPSON, of the Liverpool and London Agency for
Foreign Patent Solicitors, 6 Lord Street Liverpool in the County of Lancaster,
Civil Engineer. "IMPROVEMENTS IN ROCK DRILLING APPARATUS."-A communi-
cation to me from abroad by George McClellan Derby, First Lieutenant, Corps of
Engineers U.S.A; of Astoria, Queens County, State of New York, United
States of America
This invention belongs to that class of drill denominated tubular, in which the
bit or cutting edge of the drill is formed upon or attached to the end of a tubular
steel and by the action of which an annular section of the rock operated upon is
cut away.
The advantage of this class is that the labor that would be expended in
pulverizing the interior is saved. It belongs also to the class known as recipro-
cating which are operated upon the principle of the steam hammer. These have
their shank connected to a piston working in a cylinder; steam or compressed air
being admitted alternately before and behind the piston forces it rapidly to-and-fro,
causing the drill to strike the rock with great rapidity and force. The advantage
of the reciprocating drill besides the rapidity of its operation is that it can be used
to drill a hole at any angle to the vertical.
Heretofore so far as my knowledge extends it has not been found practicable to
operate a tubular drill with this class of machine, but only drills having a solid
steel and bit have been so worked. The diamond drill is tubular but is worked
only by a constant revolution about the axis of the tube and scratches away the
rock without striking.
The practical difficulties to be overcome in using a tubular bit on the class of
machine drills above described are 1st to dispose of the core formed and 2nd to
prevent the clogging of the drill by the accumulation of debris in the hole. These
difficulties are largely increased by the very high rate of speed at which these
machines are run and the small diameter of the holes that it is customary to drill
with them.
The object of this invention is to overcome these difficulties and to provide means
by which a tube may be employed for drilling holes under the influence of a rapid
to-and-fro motion imparted by such machinery as has heretofore been used for
thus driving solid steels, thus uniting the advantages of both classes.
The invention consists in pitching up the end or bit of the drill, and shaping the
cutting edges in such a manner as to rapidly break the rock and to prevent
clogging either on the outside or inside of the tubular shank steel. It consists
also in applying a stream of water, air, or steam to remove the broken material
from the bit, soften the rock, and preserve the temper of the drill.
In the accompanying drawing Fig 1. is a vertical section of a tubular drill
embodying the invention together with a device for communicating reciprocating
motion thereto and supplying water or other fluid to the bit of the drill. Figs 2, 3,
and are respectively an elevation, an end view, and a vertical section of the bit
of the drill
Referring to the drawings, A represents a steam cylinder of any suitable
construction, and B a piston arranged to be driven alternately forward and back
within the cylinder in a manner well understood. Affixed to the piston B and
moving therewith is a tubular piston-rod C. At its outer extremity a suitable
clamp c is formed for receiving the extremity of the drill shank D, and to the other

page_text: extremity of the shank D is secured in any suitable manner the tubular drill E
hereinafter described. The shaft D is also tubular, its perforation communicating
at one extremity directly with that of the rod C and at the other extremity
with the interior of the tubular drill E.
Surrounding the rod C. at its upper extremity is a cylindrical air or fluid
chamber F, with which communicates an inlet tube C for supplying air, steam, or
water from any suitable reservoir and under any desired amount of pressure.
Suitable packing boxes a and f surround the piston-rod C at the points where it
passes through the heads of the cylinders A and F. Suitable packing f' is also
provided, and the two cylinders are firmly united by means of pressure screws a¹
and f. A transverse aperture c¹ leads from the exterior of the piston-rod C at a
point within the air or fluid chamber F into the centre of the same and communi-
cates with the longitudinal perforation c². The aperture c¹ is at all times within
the cylinder F and through it the fluid is forced continuously into the interior of
the drill.
The continual flow of air or solvents therethrough serves both to force the
powdered rock away from the bit of the drill and thus from the hole as it is being
formed, thereby obviating the difficulties arising from the clogging of the drill
and to prevent the drill from becoming overheated and its temper thereby
destroyed.
To provide clearance and keep the drill from being clogged by the accumulation
of debris about its extremity near the bit either upon the inside or outside, the
cutting edge of the drill is made wider than the steel immediately above it, being
constructed substantially in the manner shown in Figs 2. 3. and 4.
This construction consists in forming the face of the bit transversely serrate as
shown in Fig 2, and at the same time swelling or expanding it upon its inner and
outer edges. By rendering the cutting edge serrate it will rapidly pulverize the
rock against which it is driven, and by constructing the cutting edges wider than
the steel of the drill the dimensions of the hole formed will be sufficient to permit
the drill to be reciprocated without undue friction, and the size of the core of rock
cut by the inner edge of the drill will be such as to extend within the same
without in any manner interfering with the motion of the drill.
For the purpose of conveniently obtaining the required expansion of the face of
the drill, it is preferred to form any convenient number of transverse wedge-shaped
teeth e around the extremity of the drill. The inner edges of the adjacent teeth
meet each other at their respective bases as shown at e' and the surplus metal
obtained by forming the triangular openings between the same is thrown out upon
each lateral surface of the teeth, thus causing the face e² of each tooth to be of
greater width than its base.
A drill constructed in accordance with this invention will have a polygonal form
when viewed endwise as in Fig 3, which shows the outline to be of a regular figure
having as many sides as there are teeth to the drill.
It is not necessary that the teeth be of the exact form shown in the figures, for
they may be slightly modified without departing from the principles of this
invention, as by having a U-shaped or other shaped instead of V-shaped space
between adjacent teeth.
The form given to the face of the drill in carrying out my invention will depend
both upon the size of the hole to be made and the material to be operated upon.
If a large hole is to be made it is important to have the core remain unbroken so
that it can be removed in as large pieces or sections as possible, thereby saving the
power that would be necessary to pulverize it. Or if the rock operated upon is
To do this it is
very hard then it becomes important to leave the core unbroken.
necessary that the teeth of the drill be pitched up on both the inside and outside
as represented in Fig 3, that is the face of the teeth should extend beyond the
surface of the tubular steel both on the inside and on the outside. In such cases
the tubular steel must be nearly as long as the distance the machine feeds. On
the other hand if the hole to be drilled is small, or if the rock is soft and easily

page_text: pulverized, it is not always necessary to pitch up the inside of the teeth in this
manner, the pitching up of the inside being sufficient. The drill then by its action
breaks off the core in small sections and soon pulverizes it, the debris of which is
carried away with the rest.
It will be seen that the triangular space between the teeth provides abundant
clearance for the escape of the debris. The expansion of the steel commences as
near the base of the teeth as is expedient for combining the requisite enlargement
and strength.
Having thus described the nature of this invention and the manner in which it
is to be performed as communicated to me by my foreign correspondent, I would
have it understood that I claim :-
1. A tubular rock-drill having its bit or cutting edge composed of wedge-shaped
teeth, the cutting edges of which are wider than their bases, so arranged that lines
joining their outer edges shall form a polygon, and having recesses substantially as
described between said teeth and extending above their bases, for the escape of
debris.
2. The combination substantially as hereinbefore set forth, of a tubular rock-
drill, a tubular shank rigidly secured to said drill, mechanism for giving a positive
to-and-fro motion to said drill, means substantially such as described for supplying
air, steam, or water through the interior of said shank and drill to the bit of the
drill, and a bit or cutting edge to said drill composed of wedge-shaped teeth, the
cutting edges of which are wider than their bases, so arranged that lines joining
their outer edges shall form a polygon, and having recesses between said teeth and
extending above their bases, for the escape of debris.
3. The combination with the tubular rock-drill, constructed substantially in the
manner described, of a tubular shank to which said drill is attached, mechanism for
communicating a positive to-and-fro motion to said drill, and a stream of air,
steam, or water forced through said drill, tubular support and bit.
In witness whereof I the said William Phillips Thompson have hereunto set
my hand and seal this third day of December in the year of our Lord one
thousand eight hundred and eighty three.
TIM D
זגוrnTrdThCA
1-1
F. THOMPSON (L.S.)