IMPROVEMENTS IN PERCUSSIVE ROCK DRILLS
Year: 1875

page_text: LETTERS PATENT to Frederick Edward Blacket Beaumont, of No. 2,
Westminster Chambers, Victoria Street, in the County of Middle-
sex, for the Invention of "IMPROVEMENTS IN PERCUSSIVE ROCK DRILLS."
PROVISIONAL SPECIFICATION left by the said Frederick Edward
Blacket Beaumont at the Office of the Commissioners of Patents,
with his Petition, on the 6th March 1875.
I, FREDERICK EDWARD BLACKET BEAUMONT, of No. 2, Westminster
Chambers, Victoria Street, in the County of Middlesex, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN PER-
CUSSIVE ROCK DRILLS," to be as follows:-
My Invention relates to rock drills of the kind in which compressed
air or other fluid under pressure is made to act on a piston in a cylinder
so as to give the same a reciprocating movement for the purpose of
working directly a percussive drill secured to the piston rod.
:

page_text: The chief object of my Invention is so to arrange the working parts
that they are readily accessible for cleaning, lubrication, and repair, and
can each be separately adjusted to the work which they have to do
without the necessity for access to the interior of the cylinder or slide
casings.
For this purpose I fit the cylinder to slide longitudinally on a framing
on which is fixed a screw fitted with a sleeve nut that works in a boss
at the side of the cylinder, so that when the sleeve is turned in the one
direction or the other on the fixed screw the cylinder is advanced or
retracted.
The piston is of differential area, having a large piston rod extending
through a stuffing box in the front cover of the cylinder, and a smaller
piston rod extending in like manner through the back cover. The front
end of the larger piston rod is bored up to receive the drill or boring
tool which is held in it by a screw clamp. The back end of the small
piston rod is secured to a cross head, from which project forwards three
reciprocating slotted cams, which I will now describe.
The first cam, which is caused by the motion of the piston and cross
head to reciprocate at one side of the cylinder (where it is guided to
move parallel to the axis) has a curved slot, in which works a roller
mounted on one arm of a bell-crank lever. The other arm of the bell-
crank lever is jointed to the slide rod. As the cam reciprocates the
curved sides of the cam slot acting on the roller impart to the bell crank
a rocking movement, which causes the slide to reciprocate so as to
alternato the admission and emission of the fluid that works in the
cylinder.
The second cam, which projects from the middle of the cross head over
the smaller piston rod, has also a curved or inclined slot in which works
a roller mounted on the end of an upright lever that can rock on the
piston rod as a fulcrum. This lever carries a pawl, which acts on the
teeth of a ratchet wheel fitted with a feather on the piston rod so that
the piston rod can slide through it but must revolve with it. Another
pawl mounted on the fixed framing engages with the same ratchet
wheel. As the cam reciprocates, causing the lever to rock, the pawl
of the lever at every stroke moves the ratchet wheel partly round, and
thus gives a partial rotation to the piston rod, piston and boring tool
secured thereto, and the other pawl prevents them from turning back.

page_text: The third cam, which is like the first, guided to work along the cylinder
on the opposite side from the first, has likewise a curved or inclined slot,
and acts on an upright lever, causing it to rock in a manner similar to
the second cam. This lever, which is mounted on the sleeve nut of the
advancing screw, likewise carries a pawl, which acting on the teeth of
a ratchet wheel fixed on the sleeve causes the same to turn a little at
each stroke, and thus advances the cylinder and boring tool as the hole
drilled by the latter becomes deeper. A pawl mounted on the fixed
framing and engaging with the teeth of the ratchet wheel prevents the
sleeve nut from turning backwards.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederick Edward Blacket Beaumont in the Great
Seal Patent Office on the 4th September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
EDWARD BLACKET BEAUMONT, of No. 2, Westminster Chambers,
Victoria Street, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of March, in the year of our
Lord One thousand eight hundred and seventy-five, in the thirty-eighth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Frederick Edward Blacket Beaumont, Her
special license, that I, the said Frederick Edward Blacket Beaumont,
my executors, administrators, and assigns, or such others as I, the
said Frederick Edward Blacket Beaumont, 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 PERCUSSIVE ROCK DRILLS,"
upon the condition (amongst others) that I, the said Frederick Edward
Blacket Beaumont, my executors or administrators, by an instrument
in writing under my, or their, or one of their 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

page_text: 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 I, the said Frederick Edward Blacket Beaumont,
do hereby declare the nature of the said Invention, and in what manner 5
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, reference being had
to the accompanying Sheet of Drawings, and to the figures and letters
marked thereon, that is to say :-
My Invention relates to rock drills of the kind in which compressed 1
air or other fluid under pressure is made to act on a piston in a cylinder
so as to give the same a reciprocating movement for the purpose of
working directly a percussive drill secured to the piston rod.
The chief object of my Invention is so to arrange the working parts
that they are readily accessible for cleansing, lubrication, and repair, and 1
can each be separately adjusted to the work which they have to do
without the necessity for access to the interior of the cylinder or slide
casings.
For this purpose I fit the cylinder to slide longitudinally on a framing
on which is fixed a screw fitted with a sleeve nut that works in a boss at 20
the side of the cylinder, so that when the sleeve is turned in the one
direction or the other on the fixed screw the cylinder is advanced or
retracted.
The piston is of differential area, having a large piston rod extending
through a stuffing box in the front cover of the cylinder, and a smaller 20
piston rod extending in like manner through the back cover. The front
end of the larger piston rod is bored up to receive the drill or boring tool
which is held in it by a screw clamp. The back end of the small piston
rod is secured to a cross head, from which project forwards three
reciprocating slotted cams which I will now describe.
3
The first cam, which is caused by the motion of the piston and cross
head to reciprocate at one side of the cylinder (where it is guided to
move parallel to the axis) has a curved slot in which works a roller
mounted on one arm of a bell-crank lever. The other arm of the bell-
crank lever is jointed to the slide rod. As the cam reciprocates the 3
curved sides of the cam slot, acting on the roller, impart to the bell

page_text: crank a rocking movement, which causes the slide to reciprocate so as to
alternate the admission and emission of the fluid that works in the
cylinder.
The second cam, which projects from the middle of the cross head
over the smaller piston rod, has also a curved or inclined slot, in which
works a roller mounted on the end of an upright lever that can rock on
the piston rod as a fulcrum. This lever carries a pawl, which acts on
the teeth of a ratchet wheel fitted with a feather on the piston rod, so
that the piston rod can slide through it, but must revolve with it.
Another pawl mounted on the fixed framing engages with the same
ratchet wheel. As the cam reciprocates, causing the lever to rock, the
pawl of the lever at every stroke moves the ratchet wheel partly round,
and thus gives a partial rotation to the piston rod, piston, and boring
tool secured thereto, and the other pawl prevents them from turning
back.
The third cam, which is like the first, guided to work along the cylinder
on the opposite side from the first, has likewise a curved or inclined slot,
and acts on an upright lever, causing it to rock in a manner similar to
the second cam. This lever, which is mounted on the sleeve nut of the
advancing screw likewise carries a pawl which acting on the teeth of a
ratchet wheel fixed on the sleeve causes the same to turn a little at each
stroke, and thus advances the cylinder and boring tool as the hole
drilled by the latter becomes deeper. A pawl mounted on the fixed
framing, and engaging with the teeth of the ratchet wheel prevents the
sleeve nut from turning backwards.

page_text: cylinder. To this rod is attached a cross head II, to which are connected
three reciprocating slotted cams I, K, L. The cam I is connected to
the one side of the cross head by a rod I', which passes through a guide
I on the cylinder cover, and its front end also works in a guide formed
on the side of the cylinder. This cam is formed with a slot of the
configuration shewn at Fig. 2, in which slot is a small roller M' carried
by a lever M fixed on an axis M³ carried by a bracket A' projecting from
the cylinder. On the upper end of the axis M2 is another lever M³
connected to the rod N¹ of the slide valve N. Thus as the cam I
receives a reciprocating motion from the rod G and cross head H it
imparts by means of its curved portions the requisite rocking motion
to the levers M, M, towards the end of each stroke for actuating tho
slide valve N so as to alternate the admission and emission of the fluid
under pressure. The cam K is fixed to the top of the cross head, and
has a slot inclined to the axis of the cylinder, in which works a roller O¹
mounted on the end of a vertical lever O that rocks on the rod G as a
fulcrum. This lever carries a pawl O² in gear with a ratchet wheel P
loose on the rod G, but fitted with a feather working in a groove on the
rod, so that this can slide through the ratchet wheel but must revolve
with it. Thus it will be seen that as the cam K by its oblique slot
imparts a rocking motion to the lever O as it reciprocates with the cross
head the lever by its motion in one direction will, by the ratchet
wheel P and pawl partially turn the rod G, and with it the piston, piston
rod C, and drill D during every back stroke of the piston. The lever O
and ratchet wheel P are confined within the loop Q fixed on the cylinder
cover, while the rod G slides through them, and a second pawl P¹ carried
by the loop Q, and in gear with the ratchet wheel, prevents the rod G
and piston from turning back again during the forward motion of the
piston. The cam L is formed on a rod L' secured to the cross head, and
working in a guide L on the side of the cylinder. In the slot of this
cam is a roller R' mounted on the vertical lever R that rocks on the
sleeve nut F¹ inside the boss F as a fulcrum. Ou the sleeve nut is fixed
a ratchet wheel S, in gear with which is a pawl R on the lever R.
From this arrangement it will be seen that as the cam L reciprocates
with the cross head it will impart a rocking motion to the lever R,
which by means of the pawl R² will partially turn the ratchet wheel S
and sleeve nut F', and will thus cause the drill cylinder A to advance.
It will be observed that the slot of the cam is formed with a straight
portion 7, and that so long as the drill, and consequently also the cross

page_text: head H and cam L do not advance far enough in the forward motion to
cause the whole of the inclined part of the slot to act on the lever R,
this will not be moved over sufficiently to cause the pawl R to engage
in a fresh tooth of the ratchet wheel S, so that the backward motion of
the cam will not cause the partial rotation of the sleeve nut and the
consequent advance of the drill cylinder until the drill has completed
the bore hole to such a depth as to allow of the full stroke of the piston
and cross head. The sleeve nut is prevented from turning back by a
second pawl S¹ hinged to the cylinder cover and in gear with the ratchet
wheel S. It will be readily understood that in place of the before
described arrangement of the cam K for rotating the drill any other
known contrivance may be employed for this purpose in combination
with the cam actions for working the slide and advancing the drill, and
I do therefore not limit myself to the combined use of all three above
described cam actions.
Having thus described the nature of my Invention and in what
manner the same is to be performed, I claim,-
First. The use in percussive rock drills of the reciprocating slotted
cams I and.L, actuated by a cross head from a rod connected to the .
piston for working the slide valve and for advancing the drill cylinder,
substantially as herein described.
Second. The use, in combination with the cams I and L of the
reciprocating slotted cam K for rotating the piston and drill, substan-
tially as herein described.
In witness whereof, I, the said Frederick Edward Blacket Beaumont,
have hereunto set my hand and seal, this Fourth day of. Sep-
tember, in the year of our Lord One thousand eight hundred and
seventy-five.