IMPROVEMENTS IN ROCK DRILLING MACHINES
Year: 1874

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Sutton, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN ROCK
DRILLING MACHINES."-A communication from abroad by Camille
Ferroux, of Goeschenen, in the Federal Republic of Switzer-
land.
Sealed the 4th August 1874, and dated the 23rd February 1874.
PROVISIONAL SPECIFICATION left by the said George Tomlinson
Bousfield at the Office of the Commissioners of Patents, with his
Petition, on the 23rd February 1874.
I, GEORGE TOMLINSON BOUSFIELD, of Sutton, in the County of Surrey,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN ROCK DRILLING MACHINES," to be as follows:―.
This Invention has for its object improvements in rock drilling

page_text: piston with a hollow piston rod passing through it. This hollow piston
rod passes through a stuffing box at the front end of the cylinder,
and carries the front portion of the machine with the tool carrier and
tool.
Compressed air (or other fluid under pressure) is admitted by a cock
into the rear end of the cylinder and tends constantly to press the piston
forward, and also at the same time it passes through the hollow piston
rod to the forward part of the machine, and gives a jumping motion to
the tool as is hereafter described. There is a passage to admit the com-
pressed air to the front of the piston so that when the air is shut off from 1
the rear of the piston the piston with its hollow piston rod and the front
portion of the machine will be withdrawn. This passage may be closed
by a cock or may always be left open, the front of the piston being of
less area than the rear.
The front portion of the machinc consists of a cylinder which is 1
rigidly attached to the hollow piston rod. In this cylinder there works a
piston with a solid piston rod which passes out through a stuffing box in
the front end of the cylinder. The front end of this piston rod carries
the tool carrier.
The compressed air is admitted from the rear portion of the machine a
through the hollow piston rod to a valve box, and from thence by
passages to the front and rear of the piston, the passage to the front of
the piston is always open, but that to the rear is alternately opened to
the valve box and exhaust by a slide valve. The area of the piston in
front is smaller than at the rear, so that as the valve is alternately
opened and closed the piston is moved backwards and forwards and tho
jumping motion given to the tool.
The motion of rotation is given to the tool by a shaft which is parallel
to the axis of the machine, and is carried by bearings supported by the
two rods forming the frame. This shaft is caused to rotate by a small
engine (of any convenient form) at the rear of tho machine. This
engine is worked by the compressed air or other fluid under pressure.
The section of the shaft is square and on it there is an eccentric which
by means of a ratchet gives the tool carrier an intermittent rotary
motion. There is also a cam surface capable of sliding backwards and
forwards on the shaft which actuates the valve rod of the valve for
giving the jumping motion to the tool.

page_text: The methods of controlling the advance of the hollow piston rod and
of regulating the length of stroke of the jumping piston are as follows:
-At the front end of the front cylinder a forked lever is hinged, the
forked arms of which have catches which take into teeth on the two rods
of the frame. The other arm of the lever is pressed outwards by a small
piston working in a short pipe out of the air passage at the front of the
cylinder so that the catches are pressed by the air into the teeth.
When the jumping piston rod is doing its greatest length of stroke a
projection on it just reaches and strikes against a projection on the
forked lever, thereby raising it with the catches and thus allowing the
hollow piston rod with the whole of the front portion of the machine to
advance the distance between two teeth, the stroke of the jumping
piston being diminished to the same extent. As the tool cuts into the
rock the length of stroke of the jumping piston gradually increases until
it attains its full extent, when it again lifts the catches and the appa-
ratus again advances another step and so on until the hollow piston rod
can advance no further. When this is the case the hollow piston rod is
withdrawn into its cylinder, and the whole machine is advanced and
operations recommenced and continued until the hollow piston rod has
again advanced to its full extent.
To prevent the hollow piston rod from being driven back by the per-
cussion of the tool, it carries near its front end two small transversc
cylinders whose pistons are pressed outwards by the pressure of the air
in the hollow piston rod, and take into teeth in the two rods forming the
frame of the machine, thus acting as stops to prevent the hollow piston
rod from being forced back.
When it is wished to withdraw the hollow piston rod the air (as has
been already stated) is shut off from the interior, thus the pressure is
taken off the pistons of the two small cylinders and they are no longer
pressed outwards into the teeth, and they thus leave the hollow piston
rod free to be forced back by the pressure on the front face of its
piston.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Tomlinson Bousfield in the Great Seal
Patent Office on the 22nd August 1874.
filed by the said George Tomlinson Bousfield in the Great Seal
Patent Office on the 22nd August 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of Sutton, in the County of Surrey, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of February, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said George Tomlinson Bousfield,
Her special license that I, the said George Tomlinson Bousfield, my
executors, administrators, and assigns, or such others as I, the said
George Tomlinson Bousfield, my executors, administrators, and 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 ROCK DRILLING MACHINES,”
a communication to me from abroad by Camille Ferroux, of Goeschenen,
in the Federal Republic of Switzerland, upon the condition (amongst
others) that I, the said George Tomlinson Bousfield, my executors or
administrators, by an instrument in writing under my, or their, or one of
their hands and scals, 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

page_text: The rear end of the machine consists of a cylinder carrying two rods
forming the frame of the machine. In this cylinder there works a
piston with a hollow piston rod passing through it. This hollow piston
rod passes through a stuffing box at the front end of the cylinder, and
carries the front portion of the machine with the tool carrier and tool.
Compressed air (or other fluid under pressure) is admitted by a cock
into the rear end of the cylinder and tends constantly to press the piston
forward, and also at the same time it passes through the hollow piston
rod to the forward part of the machine, and gives a jumping motion to
the tool as is hereafter described. There is a passage to admit the com-
pressed air to the front of the piston, so that when the air is shut off
from the rear of the piston the piston with its hollow piston rod and the
front portion of the machine will be withdrawn. This passage may be
closed by a cock or may always be left open, the front of the piston
being of less area than the rear.
The front portion of the machine consists of a cylinder which is
rigidly attached to the hollow piston rod. In this cylinder there works
a piston with a solid piston rod which passes out through a stuffing box
in the front end of the cylinder. The front end of this piston rod carrics
the tool carrier.
The compressed air is admitted from the rear portion of the machine
through the hollow piston rod to a valve box, and from thence by
passages to the front and rear of the piston; the passage to the front of
the piston is always open but that to the rear is alternately opened to
the valve box and exhaust by a slide valve. The area of the piston in
front is smaller than at the rear so that as the valve is alternately
opened and closed, the piston is moved backwards and forwards and tho
jumping motion given to the tool.
The motion of rotation is given to the tool by a shaft which is parallel
to the axis of the machine, and is carried by bearings supported by the
two rods forming the frame. This shaft is caused to rotato by a small
engine (of any convenient form) at the rear of the machine. This engine
is worked by the compressed air or other fluid under pressure. The
section of the shaft is square, and on it there is an eccentric, which by
means of a ratchet gives the tool carrier an intermittent rotary motion;:
there is also a cam surface capable of sliding backwards and forwards on

page_text: the shaft which actuates the valve rod of the valve for giving the
jumping motion to the tool.
The methods of controlling the advance of the hollow piston rod and
of regulating the length of stroke of the jumping piston are as follows:-
At the front end of the front cylinder a forked lever is hinged, the forked
arms of which have catches which take into teeth on the two rods of
the frame. The other arm of the lever is pressed outwards by a small
piston working in a short pipe out of the air passage at the front of the
cylinder, so that the catches are pressed by the air into the teeth.
When the jumping piston rod is doing its greatest length of stroke, a
projection on it just reaches and strikes against a projection on the
forked lever, thereby raising it with the catches, and thus allowing the
hollow piston rod with the whole of the front position of the machine to
advance the distance between two teeth, the stroke of the jumping
piston being diminished to the same extent. As the tool cuts into the
rock the length of stroke of the jumping piston gradually increases until
it attains its full extent, when it again lifts the catches, and the appa-
ratus again advances another step, and so on until the hollow piston rod
can advance no further. When this is the case the hollow piston rod is
withdrawn into its cylinder, and the whole machine is advanced and
operations recommenced and continued until the hollow piston rod has
again advanced to its full extent.
To prevent the hollow piston rod from being driven back by the per-
cussion of the tool, it carrrics near its front end two small transverse
cylinders, whose pistons are pressed outwards by the pressure of the air
in the hollow piston rod, and take into teeth in the two rods forming the
frame of the machine, thus acting as stops to prevent the hollow piston
rod from being forced back.
When it is wished to withdraw the hollow piston rod, the air (as has
been already stated) is shut off from the interior, thus the pressure is
taken off the pistons of the two small cylinders, and they are no longer
pressed outwards into the teeth, and they thus leave the hollow piston
rod free to be forced back by the pressure on the front face of its
piston.
In order that the Invention may be most fully understood and
readily carried into effect, I will proceed to described the Drawings here.

page_text: DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section, Figure 2 a plan, Figure 3 a horizontal
section of the rear cylinder, and the remaining Figures are local sections
as indicated by the lines of section.
a is the rear cylinder which is fixed as shewn to the two rods b, b,
which form the frame of the machine; c is the hollow piston rod, and d
is the passage to admit the compressed air or other fluid under pressure
to the front of the piston working in the cylinder a; e is the front
cylinder;f, the passage (which is always open) leading from the valve
box (which communicates with the hollow piston rod by a passage) to
the front of piston in the cylinder e; fis the passago to the rear of the
piston, and h is the slide valve for alternately opening this passage to the
supply and to the exhaust. This slide valve is actuated as is hcrcin-
after described; j is the shaft for giving the rotary motion to the tool; it
is caused to revolve in any convenient manner, for example, as is shown
by means of a small engine and bevel gear; % is the eccentric on this
shaft which by means of a ratchet, as is shown at the section taken on
the line E, F; Figure 1, gives an intermittent rotary motion to the tool
carrier; is a cam surface capable of sliding on the shaft j; it is carried
forward with the front portion of the machine as it advances, and at the
same time is caused by the square shaft j to revolve in the bearing m on
the front cylinder. This cam surface actuates the rod of the slide valve
, the rod being constantly pressed out of the valve box by the pressure
of air within; n is the forked lever hinged to the front end of the front
cylinder, the catches at the ends of the arms of this lever take into teeth
on the two rods b, as shewn; o is the small piston for pressing outwards
the other end of the lever ; p is the projection on the jumping piston
rod to strike against the projection n¹ on the lever n; q, q, are the two
small pistons in the front of the hollow piston rod c; these are pressed
outwards by the air into the teeth on the two bars b, and thus prevent
the hollow piston rod being driven back by the percussion of the tool.
I would remark that the method herein set forth for advancing and
withdrawing the tool with its actuating mechanism is applicable to
machines in which the tool is worked by means other than those herein
specified.
Having thus described the nature of the said Invention and the

page_text: manner of performing the same, I would have it understood that what
I claim is,-
1. The means for moving forward the tool and the parts which actuate
it as the work progresses, and for withdrawing the same when necessary,
substantially as described.
2. The construction of rock drilling machines, substantially as
described.
In witness whereof, I, the said George Tomlinson Bousfield, havo
hereunto set my hand and scal, this Twenty-first day of August,
in the year of our Lord One thousand eight hundred and seventy-
four.