IMPROVEMENTS IN MACHINERY OR APPARATUS FOR DRILLING, PROALATION
Year: 1873

page_text: LETTERS PATENT to Robert Brydon and James Shepherd Davidson,
both of Whitehaven, in the County of Cumberland, for the In-
vention of "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR DRILLING,
PROVISIONAL SPECIFICATION left by the said Robert Brydon and
James Shepherd Davidson at the Office of the Commissioners of
Patents, with their Petition, on the 3rd June 1873.
We, ROBERT BRYDON and JAMES SHEPHERD DAVIDSON, both of
Whitehaven, in the County of Cumberland, do hereby declare the nature
of our said Invention for " IMPROVEMENTS IN MACHINERY OR APPARATUS FOR
DRILLING, BORING, OR CUTTING ROCK OR OTHER HARD SUBSTANCES," to be as
follows:-
This Invention relates to machinery or apparatus of that class in which
the cutting or boring tool or drill is carried by a rod moved to and fro
by the action of the steam or other fluid on the respective sides of a
suitable piston, and our Invention is designed to render such machines

page_text: more simple and efficient in construction and operation, and less liable to
derangement than has heretofore been usual.
We construct our machine with a cylinder of uniform diameter fitted
with suitable pistons; the tappet, the head of which forms the valve, is
actuated directly from within the steam chest on the sides of the steam b
ports and between the pistons, thereby dispensing with the use of
external valve rods, stuffing boxes, and other parts.
In order to partially rotate the cutting or boring tool or drill on its
return stroke we provide a tube within the lower end of the cylinder
having a spiral groove formed, with a suitable projection fitted in in 1
connection with the piston rod. On the upper end of the tube a number
of teeth are cut, and to prevent the piston or piston rod from rotating on
its forward stroke we provide a catch or pawl, which is forced forward
by a spring into the teeth on the tube.
The cylinder is provided with a screw running parallel at the under 1
side, carried by a screw nut connected to the jacket, provided with a
parallel shaft having suitable actuating handles and a pair of small
bevelled wheels for adjusting the position of the cylinder and so feeding
the drill.
The jacket, which is made of cast steel or other metal, is connected 2
with the stand by means of a clamp. A cylindrical bar which passes
through the clamp is provided with two gripping plates at the top and
bottom respectively, so contrived that by a single set screw the jacket
can be securely fixed at any suitable angle, and as readily released for
fresh adjustment.
2
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Brydon and James Shepherd Davidson
in the Great Seal Patent Office on the 3rd December 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ROBERT
BRYDON .and JAMES SHEPHERD DAVIDSON, both of Whitehaven, in the 3
County of, Cumberland, send greeting.

page_text: our Lord One thousand eight hundred and seventy-three, in the
36th year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said Robert Brydon and James Shepherd
Davidson, Her special license that we, the said Robert Brydon and
James Shepherd Davidson, our executors, administrators, and assigns,
or such others as we, the said Robert Brydon and James Shepherd
Davidson, our executors, administrators, or assigns, should at any
time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of
Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR DRILLING,
BORING, OR CUTTING ROCK OR OTHER HARD SUBSTANCES," upon the condition
(amongst others) that we, the said Robert Brydon and James Shepherd
Davidson, our executors or administrators, by an instrument in writing
under our hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of
the said Letters Patent.
NOW KNOW YE, that we, the said Robert Brydon and James
Shepherd Davidson, do hereby declare the nature of our said Invention,
and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement, reference
being had to the accompanying Drawings and to the letters and figures
marked thereon, that is to say:-
Our said Invention relates to machinery or apparatus of that class in
which the cutting or boring tool or drill is carried by a rod moved to and
fro by the action of the steam or other fluid on the respective sides of a
suitable piston or pistons, and our Invention is designed to render such
machines more simple and efficient in construction and operation, and
less liable to derangement than has heretofore been usual.
We construct our machine with a cylinder of uniform diameter, fitted
with two pistons; the tappet, the head of which forms the valve, is
actuated directly from within the steam chest on the sides of the steam
ports and between the pistons, thereby dispensing with the use of
external valve rods, stuffing boxes, and other parts.

page_text: In order to partially rotate the cutting or boring tool or drill on its
return or upstroke we provide a tube within the lower end of the cylinder,
having a spiral groove formed therein, within which groove works a
suitable projection or feather in connection with the piston rod. On the
upper end of the tube a number of ratchet teeth are cut, and in order to
prevent the piston or piston rod from rotating on its forward or down-
ward stroke we provide a catch or pawl, which is forced forward by a
spring into the teeth on the tube, and allows the tube to turn freely when
the piston is making its forward stroke, but holds the tube firmly during
the backward stroke.
The cylinder is provided with a screw running parallel at the under
side, carried by a screwed nut connected to the jacket, provided with a
parallel shaft having suitable actuating handles and a pair of small
bevelled wheels for adjusting the position of the cylinder, and so feeding
the drill.
The jacket, which is made of cast steel or other metal, is connected
with the stand by means of a peculiar clamp. A cylindrical bar, which
passes through the clamp, is provided with two gripping plates at the
top and bottom or opposite sides respectively, so contrived that by a
single set screw the jacket can be securely fixed at any suitable angle,
and as readily released for fresh adjustment.
And in order that our said Invention may be fully understood we shall
now proceed more particularly to describe the same, and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings,
the same letters of reference indicating corresponding parts in all the
Figures.
Figure 1 of our Drawings represents a longitudinal section of our
improved rock drilling apparatus; Figure 2 is a transverse section of the
same taken along the line 1, 2, in Figure 1; and Figure 3 is a detail
elevation of the spiral slotted tube detached.
A is the working cylinder, and B is the piston rod carrying the double
piston C, C, and passing through the cylinder neck. Upon the piston
rod and within the cylinder neck there is fitted loosely a tube D, held in
position by the screwed cap D¹, and having a spiral groove a cut in it, as
shown in Figure 3, for rotating the drill on its upward or backward
stroke, a projection or feather being fitted into the piston, and working
along the spiral slot a in the said tube. On the upper end of the tube D

page_text: there are cut a number of ratchet teeth c, into which a spring catch d,
held in position by a cap and two screws d³, engages, it being forced
forward by the spring e. The teeth and catch are so arranged as to
prevent the drill from rotating on its forward stroke by leaving the tube
itself free to rotate during such stroke, but during the time the drill is
making its backward stroke, thereby tending to turn the tube in the
contrary direction the catch d holds such tube stationary, and conse-
quently the piston rod and drill are compelled to rotate slightly. E, E, are
washers to prevent concussion, or to act as buffers for the piston; F is
our peculiar valve, in connection with which there is an arm G, which is
formed with a stud or projection fat its extremity, which is struck by
the two pistons alternately, thereby imparting the requisite reciprocating
motion to the valve F. The said valve vibrates on a spindle or fulcrum H,
which is passed through the casing I, and fixed by a nut, as shewn in
Figure 2.
An exhaust chamber or recess is formed in the face of the valve,
which works in contact with a port face in the valve casing I, the two
steam ports, with their passages 9, 9, leading to opposite ends of the
cylinder, and the exhaust port h leading to the atmosphere, being
arranged in a similar manner to the corresponding ports of an ordinary
steam cylinder worked by a slide valve, excepting that in lieu of having
parallel sides these ports are made with their sides radiating from the
centre of vibration of the valve. The valve casing I is fitted and fastened
with bolts, as shewn in Figure 2, and into it passes the steam or other
fluid for working the machine by the pipe and stop cock K. L is a feed
screw running parallel with the cylinder, and fixed to projections or
lugs M, M, on the cylinder. On this screw works a travelling nut N,
carrying a mitre wheel O, into which gears another mitre wheel P, fast
on the spindle Q, which has a handle R attached, as shewn in Figures 1
and 2, for feeding the drill by hand. S is a bracket attached to the
jacket T, and having a box formed on its inner side to hold the nut and
mitre wheel N and O in position.
In some cases we propose to feed forward the drill by a self-acting
arrangement, to which however we lay no claim. This arrangement
consists in forming a series of cog teeth on the outer end of the tube D,
and to make an opening in the side of the cap D¹ to enable such teeth to
gear into a corresponding pinion fast on the end of a spindle, which is
passed through the feed screw L, such screw. being made hollow or

page_text: $
tubular for that purpose.
A conical friction collar or boss is formed on
this pinion, and is tightened into the hollow of the screw by a nut on
the opposite end of the internal spindle. The feed screw in this arrange-
ment is free to rotate in its bearings in the cylinder, and the nut is a
fixture in the jacket. At every movement of the tube it will rotate
slightly the feed screw, and the feed is thus rendered self-acting.
U is a clamp, through which passes a cylindrical bar V, provided with
two gripping plates i and k at the top and bottom or opposite sides, so
contrived that by a single set screw W the machine can be secured at
any angle and as readily released. For this purpose the clamp is formed
with a projecting screwed boss l, which enters the jacket T on the
cylinder, and is secured therein by means of a screwed collar m. The
clamp U and jacket Tare made a working fit, so as to allow the machine
to be turned freely on the boss 7 to any vertical angle desired when
released by the set screw W. The releasing of the set screw W also
admits of the machine being turned or adjusted on the cylindrical bar V
to any desired horizontal angle. On tightening the set screw again the
bar V will be gripped firmly between the gripping plates i and k, thus
securing the clamp on the bar, whilst at the same time the gripping
platek will by being pressed against the surface of the jacket T at its
ends tighten the clamp in the jacket; thus a double grip is obtained on
tightening the set screw, and both the grips are simultaneously released
on loosening the same screw.
•
Having now described and particularly ascertained the nature of our
said Invention, and the manner in which the same is or may be used or
carried into effect, we would observe in conclusion that what we consider
to be novel and original and therefore claim as the Invention secured to
us by the herein-before in part recited Letters Patent is,―
First. Forming the valve for a rock drilling machine in the head itself
of a tappet lever, worked by the pistons in the actuating cylinder, sub-
stantially as herein-before described and illustrated by the Drawings
annexed.
Second. The combination of a tube through which the piston rod
works, having a spiral slot and ratchet teeth, with a detent, substantially
in the manner and for the purpose herein-before described and illustrated
by the Drawings annexed.

page_text: Third. The combination of two gripping plates situate respectively
above and below or on opposite sides of a cylindrical rod or bar, with a
single set or tightening screw when arranged and made to operate, sub-
stantially in the manner and for the purpose herein-before described and
illustrated by the Drawings annexed.
In witness whereof, we, the said Robert Brydon and James
Shepherd Davidson, have to this our Specification set our hands
and seals, the Twenty-fourth day of November One thousand
eight hundred and seventy-three.