AN IMPROVED MACHINE FOR DRILLING OR PERFORATING ROCKS OR OTHER HARD SUBSTANCES
Year: 1881

page_text: LETTERS PATENT to James McCulloch, Engineer, and John Henry Holman
and James Miners Holman, both of the Camborne Foundry and Engine
Works, all of Camborne, in the County of Cornwall, for an Invention of "AN
PROVISIONAL SPECIFICATION left by the said James McCulloch, and John
Henry Holman, and James Miners Holman at the Office of the Commissioners
of Patents on the 19th October 1881.
JAMES MOCULLOCH, Engineer, and JOHN HENRY HOLMAN and JAMES MINERS
HOLMAN, both of the Camborne Foundry and Engine Works, all of Camborne,
in the County of Cornwall. "AN IMPROVED MACHINE FOR DRILLING OR
PERFORATING ROCKS OR OTHER HARD SUBSTANCES."
Our Invention relates to an improved machine for drilling or perforating rocks
or other hard substances, and comprises several improvements hereinafter described,
which have for their object to provide a machine which will be simple in its
construction and operation, compact and durable, and not liable to become disabled
through the working parts getting out of order.
In carrying the said Invention into practice we provide three cylinders all cast
in one piece, and in such a manner that they are parallel with each other, that is
to say, there is a central or main cylinder between two side cylinders, the latter
being of considerably smaller diameter than the former. The central cylinder is
the working one, namely, the one in which the pistons for operating the drill are
situated. The two side cylinders are designed to receive the screws and nuts
employed for feeding forward the machine, and the outer surfaces of these two
cylinders serve as guides for the cradle. By means of this arrangement we are
enabled to provide a casting which is comparatively light and strong, and all the
parts thereof may be made of proportionate thickness, thus protecting the working
cylinder from breakage; moreover this arrangement provides means whereby the
cylinders and other parts may be readily balanced in the cradle, and the strain

page_text: upon the feed-nuts, feed-screws, and guides will be equalized, thus preventing
undue wear.
Our said machine may be operated by steam, air, or other suitable fluid under
pressure, and for this purpose we provide in the main or central cylinder two
inlet ports, and there is an aperture between the two ports which serves as an
exhaust port, also to receive a tappet of triangular form which is pivotted to
oscillate in this aperture to operate the slide valve. This aperture extends entirely
through the wall of the cylinder and affords communication, with the interior
thereof, so that all back pressure upon the pistons is prevented, as any steam or
other fluid which may pass the pistons will immediately escape through this
aperture and be conducted to the outer atmosphere. A steam chest is fitted upon
the central cylinder, and in this chest there is a flat side-valve having a small
projection at each end, which projections move in and out of corresponding recesses
in the walls of the steam chest as the machine works, each recess being provided
with a small steel washer and an india-rubber buffer so as to take off all jar of the
slide valve. One end of the aforesaid tappet enters a recess in the under side of
the valve, and the valve is thus operated as the tappet oscillates on its pivot.
Within the main or central cylinder there is a piston rod, to the outer end of
which the tool is secured. Within the cylinder this rod has three pistons, thus
equalizing the wear throughout the cylinder. The pistons have rounded edges, and
are forged in one piece with the rod. The central piston operates the tappet which
moves the slide valve.
The pistons and rod are rotated by means of a twisted bar which works through
the rear piston and into the piston rod, and through the upper or rear cylinder
cover, upon the outside of which there is a ratchet wheel and pawls. The pistons
and rod may be rotated by hand or automatically, by pulling the pawls out of or
in gear with the wheel. When the rotation is to be effected by hand, the pawls
are thrown out of gear and a crank handle is placed on the outer end of the
twisted bar, and thus the rod and piston may be rotated as desired.
The cradle and guides which fit upon the outside of the small cylinders are made
in separate pieces, so that any wear of these parts may be taken up or compensated
for.
The two screws for effecting the feeding forward of the machine are made with
left handed threads, and work into the side cylinders through nuts at the rear end
thereof. The unthreaded portion of the screw rods at the rear thereof passes
through a bridge piece or extension of the cradle, and the outer end of each screw
rod is furnished with a toothed wheel, each of which wheels gears with a central
wheel whose spindle is secured to the rear of the extension; a cranked handle is
attached to the spindle of this central wheel or to the end of the screw rods, and
by rotating this handle the machine is caused to be fed forward.
The ends or covers of the central cylinder are secured to the latter by bolts,
which pass from end to end of the cylinder. The upper cover serves to keep the
feed nuts in their place.
We prefer to fit the outer end of the piston with a tool holder made according to
the Specification of former Letters Patent granted to James McCulloch, the Sixth
day of December A.D. 1880, No. 5084.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James McCulloch and John Henry Holman, and James Miners
Holman in the Great Seal Patent Office on the 19th April 1882.
JAMES MCCULLOCH, Engineer, and JOHN HENRY HOLMAN, and JAMES MINERS
HOLMAN, both of the Camborne Foundry and Engine Works, all of Camborne,
in the County of Cornwall. "AN IMPROVED MACHINE FOR DRILLING OR
PERFORATING ROCKS OR OTHER HARD SUBSTANCES."
Our Invention relates to an improved machine for drilling or perforating rocks
or other hard substances, and comprises various improvements hereinafter described,
which have for their object to provide a machine which will be simple in its
construction and operation, compact and durable, and not liable to become disabled
through derangement of its working parts.
Our improved machine may be operated by the pressure of steam, air, or other
fluid. Its construction is illustrated in the accompanying Drawings, in which
Figure 1 is a plan or top view of a machine constructed according to our
Invention.
Figure 2 is a central longitudinal vertical section of the same.
Figure 3 is an elevation of the rear end of the cylinder.
Figure 4 is a vertical transverse section on the line x, x, Figure 1.
Like letters indicate the same parts throughout the Drawings.
A is the frame or cradle of the machine, which may be mounted in any suitable
supports adapted to the particular kind of work to be performed by the said
machine. a is the body, which is constructed of cast iron or other suitable metal,
and which has formed centrally therein the cylinder b, and also has parallel with
and on opposite sides of the said cylinder the guides. c. These two guides serve to
support the body a in the cradle A, as hereinafter described, and are bored or made
tubular to permit the feed screws d to pass through them, as shewn. By this
arrangement we are enabled to form the body of the machine of a casting which is
comparatively light and strong, and has all of its parts of proportionate thickness,
thus protecting the cylinder from fracture or other injury. Moreover this arrange-
ment provides means whereby the cylinder b, the guides c, and other parts may be
accurately balanced in the cradle, and the strain upon the feed nuts e, feed-
screws d, and guides c will be equalized, thus preventing undue wearing of any of
the parts.
We provide the cylinder b with a steam chest or casing b¹, which encloses a slide
face at b On this face we fit a slide valve f, properly arranged and operated as
hereinafter described, to distribute and exhaust the steam or other fluid through
the ports g, h, i. g, i, are the inlet ports, and h is the exhaust port, which also
serves for the reception of a tappet j, preferably of the form shewn. This tappet is
pivoted to oscillate in and project through the said exhaust port or aperture into
the cavity of the slide valve f, and imparts to the latter the required to-and-fro
motion for opening and closing the ports. k is the piston rod, to the outer end of
which the tool is secured. Within the cylinder b this rod has three pistons m, n, o,
which are preferably formed by forging them in one piece with the said rod. The
pistons m, n, divide the space within the cylinder into three parts, viz., the two
ends and the central part. The steam or other fluid is admitted alternately into
the two ends during the working of the machine, and passes therefrom through the
port h into the central part between the pistons m, n, whence it is exhausted
through the ports h¹. The central piston o is provided to engage with and operate
the tappet j, which moves the slide valve. The above described arrangement of
the pistons equalizes the wear of the cylinder's surface, and there will be no back

page_text: pressure upon the pistons m, n, as any of the steam or other fluid which may enter
the space between these pistons m, n, will immediately escape through the
apertures h into the outer atmosphere.
The aforesaid slide valve has at its ends small projections f¹, which move in and
out of corresponding recesses in the walls of the steam chest 6' during the working
of the machine, each recess being provided with a buffer composed of a steel-
washer p and an india-rubber cushion p'. These buffers prevent jarring of the
slide valve while the same is moved to and fro by the oscillations of the tappet on
its pivot ƒ³
The piston rod is rotated and with it the drill or tool by means of a twisted
bar g, which passes through the rear cylinder cover and works through the rear
piston and into the said piston rod. Outside of the said cylinder cover we arrange
a ratchet wheel r and pawls 8, as shewn in Figures 1 and 3. The said wheel and
pawls are so arranged that the twisted bar q is held stationary, and therefore
rotates the piston rod when the latter moves backward, and the said bar is then
released by the pawls, so that during the forward movement of the said piston rod
the latter does not rotate. The said piston rod k is thus rotated automatically;
but if desired its rotation may be performed by hand. For this purpose the pawls
are disengaged from the said wheel, and a crank handle is placed on the outer end
of the twisted bar for manipulating the same.
The two screws d for feeding forward the body of the machine, and thereby
causing the drill or tool to advance as the work progresses, are preferably made
with left-handed threads, and work through nuts e secured in the rear end of the
said hollow guides. The unthreaded portion of each of the said screws or screw-
rods at the rear thereof extends through a bridge or cross piece v attached to or
forming part of the cradle, as shewn in Figure 1. The outer end of each screw-rod
is furnished with a toothed wheel w; these wheels gear with a central wheel x
mounted on a short shaft x¹, secured and free to rotate in the cross piece v. A
crank handle is attached to the shaft x¹ of this central wheel, and by rotating
this handle the feed motion of the machine is effected. Instead of attaching the
crank handle to the central wheel we may apply the same to either of the screw-
rods.
The ends or covers of the central cylinder are preferably secured to the latter by
bolts, which extend from end to end of the cylinder b. The rear cover is extended
over the feed nuts e, as shewn in Figure 1, and serves to keep them in place.
The guide ways A', which fit upon the outside of the hollow guides c, are made
separate from the cradle A, so that these guideways may be adjusted to take up or
compensate for any wear of these parts, as will be readily understood by reference
to Figure 4 of the Drawing.
We prefer to fit the outer end of the piston with a tool holder, made according
to the Specification of former Letters Patent granted to James McCulloch the Sixth
day of December A.D. 1880, No. 5084.
Having thus fully described our said Invention, and the manner of performing
the same, we wish it understood that we claim,―
First. The main portion or body of the machine, consisting of a single piece or
casting with the cylinder, and the two hollow guides formed therein, substantially
as and for the purposes specified.
Second. The alide valve operated by a tappet projecting upwards into its
interior, and provided at its ends with projections arranged and operating in
combination with the cushioned recesses, substantially as and for the purposes set
forth.
Third. The combination with the said cylinder and the hollow guides of the
two feed screws extending through the feed nuts, and into or through the said
guides, and operated substantially as and for the purpose specified.
Fourth. The combination with the said main body or casting of the cradle with
its guideways constructed to permit the taking up or compensation for the wear of
the parts, substantially as specified.

page_text: Fifth. A machine for drilling or perforating rocks or other hard substances,
consisting of the parts constructed and combined, substantially as shown in the
accompanying Drawings, and operating as set forth.
In witness whereof, we, the said James McCulloch, John Henry Holman,
and James Miners Holman, have hereunto set our hands and seals, this
Fifteenth day of April, in the year of our Lord One thousand eight
hundred and eighty two.
JAMES MOCULLOCH.
JOHN HENRY HOLMAN.
(L.S.)
(L.S.)
JAMES MINERS HOLMAN. (L.S.)