Improvements in and relating to Rock Drills.
Year: 1899

page_text: [Communicated from abroad by RAND DRILL COMPANY, of No. 100, Broadway,
New York, United States of America, Manufacturers.]
Improvements in and relating to Rock Drills.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent.Agents,
45, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:--
My invention relates to improvements in the valve operating mechanism for
rock. drills, and consists in the provision of means for operating the valve con-
trolling the admission and exhaust of the motive fluid to and from the cylinder,
independent of the means employed normally, or when a drill is running under
normal conditions.
The object of my invention is to permit short strokes to be made by a recipro-
cating piston.
In rock drilling the use of short strokes at certain times is of great advantage.
In drilling a hole it is always better to start with a short stroke, no matter
what the conditions. Should it be desired to drill a hole otherwise than per-
pendicular to the surface, the use of a short stroke would obviate the necessity
of "pointing, off." Again, should a drill become jammed, a few short strokes
might readily clear it.
The apparatus for carrying out my invention comprises the cylinder of a rock
drill of ine reciprocating type; the shell upon which same is mounted; the feed
screw operated in the usual or any desired manner: the reciprocating piston
having the usual contracted central portion, and the bevelled shoulders for
operating the tappet or rocker which normally controls the valve, the rocker
or tappet pivoted in an opening in the cylinder casting.
A reciprocating valve is employed of cylindrical form and which fits in the
valve chamber in which it is arranged to reciprocate.
The motive fluid commonly used with this type of drill is compressed air, and
for convenience I will refer to the said motive fluid throughout the specification
as compressed air: but I do not wish to be limited to the use of same as I may
use other motive fluids, such for instance as steam.
The admission ports unite in a common passage-way in an intermediate casting
and from there pass to an admission valve, to which a compressed air hose is
attached.
I provide an inlet port connecting with the front end of the cylinder and
the valve chamber and an inlet port connecting with the rear end of the cylinder
and the valve chamber.
Exhaust ports discharging into the outer atmosphere are provided at the
front and rear of the valve chest.
:
The reciprocating cylindrical valve is provided with two annular grooves, which
alternately connect the ports with their respective inlet ports or exhaust ports.

page_text: The valve is further provided with a central annular groove, which is adapted
to engage with one arm of the rocker or tappet. The rocker is provided with
two extending arms having bevelled faces, which engage the aforementioned
bevelled, shoulders on the piston.
When the parts are in a certain predetermined position air is admitted through
the port to the rear of the cylinder and the piston moves forward. The com-
pressed air from the other end of the cylinder is being exhausted to the atmos-
phere
Upon the further movement of the piston, the rocker, by reason of the contact
of the bevelled face with the bevelled shoulder, will partially rotate upon its
pivot. The piston valve will be moved forward, closing the admission of air to
the front port and opening said port to the front exhaust. At the same time it
will close the rear exhaust and open the admission to the port allowing the
,compressed air to enter the front end of the cylinder. This will cause a return
movement of the piston and under normal conditions the piston will continue to
return until the hevelled shoulder strikes the bevelled face of the rocker or tappet.
A hollow cylindrical valve is mounted in the discharge end of the exhaust
rear port. This valve is provided with a port normally in register with the
exhaust. Said port is open at the end so that the exhaust air will pass freely
through the same. If now the said cylindrical valve be rotated so that its port
will be out of register with the exhaust port, the air in the front of the piston
and that which is contained in the port, the front end of the valve chamber and
the exhaust port will be prevented from exhausting to the atmosphere.
Now therefore, if the said valve be rotated, a further forward movement of
the piston and the reciprocation of the piston valve to the other
end of the valve casing consequent thereupon as previously explained
will further compress the air which is confined. and an elastic pres-
sure will be applied to the forward end of the piston valve:
so that
when the piston begins its rearward movement and frees the end of the tappet,
the piston valve will be forced rearwardly and the admission port again opened.
The above series of operations will be repeated so long as the hollow cylin-
drical valve remains closed, the piston making a series of short and rapid strokes
until, upon the rotation of the said valve so as to bring the ports again in register,
the elastic pressure in front of the piston is removed. The valve will then only
be moved by the tappet which is operated by the piston at or near the end of a
full stroke in either direction, and the piston will be permitted to make said full
strokes.
I preferably provide the cylindrical valve with a stem, upon which is secured
a head, which may be conveniently grasped by the fingers for causing the
rotation of the said valve. I also provide a spring, one end of which engages with
the valve's stem or head and the other end of which engages the intermediate
casting. The tension of the spring keeps the valve so that the ports are in
register. It is thus necessary to hold the valve in its closed position when it is
desired to make short strokes. This is of course not an essential part of my
invention, but it is a form of construction which I have found most suitable.
I have also found thus far that enough air would leak past the valve to com-
pensate for the slight additional amount of air taken in upon each short return
stroke but if desirable I may provide a suitable stop so that the valve could
not be entirely closed, thereby leaving whatever space might be necessary to
exhaust the surplus air: but such opening would of course not be large enough
to interfere with the necessary compression in order to apply the elastic pressure
to the rear of the reciprocating valve.
Such limiting stop is provided, for instance as a pin carried by the valve and
which moves in a recess in the casting. Said pin will limit the movement of the
valve in either direction by striking the end walls of the recess. The throttle
valve may conveniently be used when the short stroke valve is operated to
modulate the force of the blow as well as the length of the stroke,

page_text: I do not wish to be limited to the precise form or combination of parts or the
exact details of construction as herein shown and described, as they may obviously
be varied within wide limits without departing from the spirit and scope of my
invention.
Dated this 3rd day of March 1899.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements in and relating to Rock Drills.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent' Agents,
45, Southampton Buildings, in the County of Middlesex, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
My invention relates to improvements in the valve operating mechanism of
rock drills, and consists in the provision of means for operating the valve con-
trolling the admission and exhaust of the motive fluid to and from the cylinder,
independent of the means employed normally, or when a drill is running under
normal conditions.
The object of my invention is to permit short strokes to be made by a recipro-
cating piston.
In rock drilling the use of short strokes at certain times is of great advantage.
In drilling, a hole it is always, better to start with a short stroke, no matter
what the conditions. Should it be desired to drill a hole otherwise than per-
pendicular to the surface, the use of a short stroke would obviate the necessity
of pointing off." Again, should a drill become jammed, a few short strokes
might readily clear it.
*
I will now proceed to describe my invention, with reference to the accom-
panying drawing and then point out the novel features in claims.
In the accompanying drawing
Figure 1 is a central longitudinal section of a portion of a rock drill, embodying
my invention.
Figure 2 is a transverse section of the same, the plane of section being taken
on the line of Figure 1.
Figure 3 is a detail view in horizontal section of the independent valve employed
and its surrounding parts.
Figures 4 and 5 are details in transverse section of portions of said valve,
illustrating certain details of construction.
Figure 6 is a detail taken on the same section but viewed from the opposite
direction.
:
Similar reference characters designate corresponding parts in the several
figures.
Reference character a designates the cylinder of a rock drill of the reciprocating
type the shell upon which same is mounted: the feed operated in the usual
or any desired manner. d designates the reciprocating piston having the usual
contracted central position, and the bevelled shoulders e and f for operating the
tappet or rocker which, normally controls the valve.
designates the rocker or tappet pivoted in a recess in the cylinder casting.
h designates a reciprocating valve which is here shown of cylindrical form
and which fits in the valve chamber h h in which it is arranged to reciprocate."
i, i are the admission ports for the motive fluid. The motive fluid commonly

page_text: used with this type of drill is compressed air, and for convenience I will refer
to the said motive fluid throughout the specification as compressed air; but I
. do not wish to be limited to the use of same as I may use other motive fluids,
such for instance as steamı.
The ports i, i unite in a common passage-way in the intermediate casting and
from there pass to an admission valve, to which a compressed air hose is attached.
I have not shown this in detail in the drawing as it forms no part of my
invention.
k is an inlet port connecting with the front end of the cylinder and the valve
chamber, and is an inlet port connecting with the rear end of the cylinder and
the valve chamber.
m is an exhaust port discharging to the outer atmosphere at m m; and n is
an exhaust port discharging to the outer atmosphere at n n.
The reciprocating cylindrical valve h is provided with two annular grooves
which alternately connect the ports or with their respective inlet ports or
exhaust ports. The valve is further provided with a central annular groove
which is adapted to engage with one arm of the rocker or tappet g. The rocker
is provided with two extending arms having bevelled faces, e e, f f, which engage
the aforementioned bevelled shoulders e and f on the piston d.
When the parts are in the position shown in Figure 1, compressed air is being
admitted through the port to the rear of the cylinder and the piston is moving
forward. It has almost reached the completion of its stroke. The compressed
air from the other end of the cylinder is being exhausted through the ports k, m,
to the atmosphere at m m.
Upon the further movement of the piston, the rocker, by reason of the contact
of the bevelled face f f with the bevelled shoulder f, will partially rotate upon
its pivot. The valve will be moved forward, closing the admission of air to
the port and opening said port to the exhaust n. At the same time it will
close the exhaust m and open the admission to the port k allowing the com-
pressed air to enter the front end of the cylinder. This will cause a return move-
ment of the piston and under normal conditions the piston will continue to return
until the bevelled shoulder e strikes the bevelled face e c of the rocker or tappet g.
I however provide an independent short stroke contrivance containing a
cushioning device. The cushioning device is so arranged as to apply, when
required, an elastic pressure to move the reciprocating valve intermediate of a
full stroke of the piston.
The cushioning action is preferably applied directly to the front of the recipro-
cating valve, and may be applied in any manner desired and by any suitable
mechanism.
I have shown and will now describe an elastic pressure controller comprising a
valve, by the manipulation of which, pressure is caused to accumulate, or to be
released, according to which way the valve is turned. The position of the said
valve hence controls.the fluid pressure, which, when caused to accumulate by the
operation of the valve or pressure controller in one direction, will move the
reciprocating valve and when released by the operation of the valve or pressure
controller in the other direction, will cause the reciprocating valve to be moved
only by the action of the tappet or rocker.
is the elastic pressure controller in the form of a hollow cylindrical valve
mounted in the discharge end of the exhaust port m. This valve is provided
with a port p normally in register with the exhaust port m and is open at the
end so that the exhaust air will pass freely through same. If now the said
valve o be rotated so that the port p will be out of register with the port m,
the air in the front of the piston and that which is contained in the port k, the
front end of the valve chamber and the port m will be prevented from exhausting
to the atmosphere.
Now therefore, if the said valve o be rotated at about the time when the
other parts are in the position shown in Figure 1, a further forward movement

page_text: of the piston and the reciprocation of the valve h to the other end of the valve
casing consequent thereupon as previously explained, will further compress the
air which is locked from escape, and an elastic pressure will be applied to the
forward end of the valve h: so that when the piston d begins its rearward
movement and frees the end of the tappet g, the valve his forced rearwardly
and the admission port again opened.
The above series of operations will be repeated so long as the valve o remains
closed, the piston d making a series of short and rapid strokes until upon the
rotation of the valve o so as to bring the ports p, m, again in register, the .
elastic pressure in front of the piston is removed. The valve will then only
be moved by the tappet which is operated by the piston at or near the end of a
full stroke in either direction, and the piston will be permitted to make said full
.strokes.
I preferably provide the valve.o with a stem r, upon which is secured a
head, which may be conveniently grasped by the fingers for causing the
rotation of the said valve. I also provide a spring, one end of which
engages with the valve stem or head and the other end of which engages the
intermediate casting j. The tension of the spring keeps the valve so that the
ports and m are in register. It is thus necessary to hold the valve in its
closed position when it is desired to make short strokes. This is of course not
an essential part of my invention, but it is a form of construction which I have
found most suitable.
I have also found thus far that enough air would leak past the valve to
compensate for the slight additional amount of air taken in upon each short
return stroke; but if desirable I may provide a suitable stop so that the valve
could not be entirely closed, thereby leaving whatever space might be necessary
to exhaust the surplus air; but such opening would of course not be large
enough to interfere with the necessary compression in order to apply the elastic
pressure to the end of the reciprocating valve.
Such limiting stop is shown in the drawing as a pint carried by the valve and
which moves in a recess in the casting . Said pin will limit the movement
of the valve in either direction by striking the end walls of the recess u. The
throttle valve may conveniently be used when the short stroke valve o is
operated to modulate the force of the blow as well as the length of the stroke:
I do not wish to be limited to the precise form or combination of parts or
the exact details of construction as herein shown and described, as they may
obviously be varied within wide limits without departing from the spirit and
scope of my invention.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondents, I declare that what I claim is:-
1. In a rock drill, the combination with a cylinder, a piston, and a valve for
controlling the admission and exhaust of the motive fluid thereto, of mechanism
for reversing the position of the valve at or near the end of each stroke of the
piston and an independent short stroke contrivance forming a cushioning device
by means of which the position of the valve may be reversed at a point in the
stroke intermediate of the points at which reversal of the valve by the main
valve operating means is produced.
2. In a rock drill, the combination with a cylinder, a piston and a valve for
controlling the admission and exhaust of the motive fluid thereto, of means
operated by the piston to move the valve at or near the end of a full stroke of
said piston, and an elastic pressure controller, by the manipulation of which,
pressure is applied to move the valve intermediate of the full stroke of the piston.
3. In a rock drill, the combination with a cylinder, a piston, and a valve for
controlling the admission and exhaust of the motive fluid thereto, of a rocker or
tappet operated by the piston to move the valve at or near the end of a full stroke

page_text: of the piston, and an elastic pressure controller, by the manipulation of which,
pressure may be applied to the valve to move same intermediate of a full stroke
of the piston.
4. In a rock drill, the combination with a cylinder, a piston, and a valve for
controlling the admission and exhaust of the motive fluid thereto, of a rocker
or tappet operated by contact with the piston to move the valve at or near the
end of a full stroke of the piston, and an elastic pressure controller by the
manipulation of which, pressure, applied by the movement of the piston, may
be applied independently of the action of the said piston on the rocker, to the
valve to move same intermediate of the full stroke of the piston.
5. In a rock drill, the combination with a cylinder, a piston, and a valve for
controlling the admission and exhaust of the motive fluid thereto, of means
operated by the piston at the end of its stroke to move the valve in one direction,
and means whereby an elastic pressure may be applied to move the valve in the
opposite direction prior to its completion of a full stroke and immediately upon
its release from the action of the piston operated means.
6. In a rock drill, the combination with a cylinder, a piston, and a valve for
controlling the admission and exhaust of the motive fluid thereto, of a rocker or
tappet operated by the piston at the end of its stroke to move the valve in one
direction, and means whereby an elastic pressure may be applied to move the
valve in the opposite direction, prior to its completion of a full stroke and
immediately upon its release from the action of the tappet.
7. In a reciprocating engine, the combination with a cylinder, a piston and
a distributing valve, of ports for the admission and exhaust of the motive fluid
to and from the cylinder and means for closing the exhaust at one end of the
cylinder independently of the distributing valve, whereby the compression of the
motive fluid will move the said distributing valve.
8. In a reciprocating engine the combination with a cylinder, a piston, and
a reciprocating valve, of ports, for the admission and exhaust of the motive
fluid to and from the cylinder, controlled by said valve and an independent valve
arranged in the exhaust port whereby the said exhaust port may be closed inde-
pendently of the reciprocating valve to shorten the stroke of the engine.
9. In a reciprocating engine, the combination with a cylinder and a piston of
an inlet for the motive fluid, two admission ports for admitting the motive fluid
to the front or rear of the said piston in the cylinder as the said ports are
alternately connected with the said inlet, two exhaust ports for exhausting the
said motive fluid as the said exhaust ports are alternately connected with the
respective admission ports, a reciprocating valve for alternately connecting the
said admission ports with the inlet, and with the exhaust, and an independent
valve provided in one of said exhaust ports, whereby the compression of the
motive fluid will move the said reciprocating valve.
10. In a reciprocating engine, the combination with a cylinder, a piston and
a reciprocating valve, of ports for the admission and exhaust of the motive
fluid to and from the cylinder controlled by said valve, an independent valve
arranged in the exhaust port whereby the compression of the motive fluid will 4
move the said reciprocating valve and stops for limiting the movement of the
valve whereby sufficient opening is left when the valve is in closed position to
permit the escape of superfluous motive fluid.
11. In a reciprocating engine, the combination with a cylinder, a piston, a
valve chamber having a cylindrical bore, a cylindrical piston valve adapted to
reciprocate therein, and admission and exhaust ports, of an independent valve
arranged in one of said exhaust ports, and a communication between the said
exhaust port and the valve chamber in front of the cylindrical piston valve
whereby the compression of the motive fluid will move said cylindrical valve.
12. In a reciprocating engine, the combination with a cylinder, a piston, a
valve chamber having a cylindrical bore, a cylindrical piston valve adapted to
reciprocate therein, and admission and exhaust ports, of a rocker operated by the

page_text: said piston to move the valve- at or near the end of a full stroke of the piston,
and an independent valve arranged in one of said exhaust ports whereby the
compression of the motive fluid will move the said cylindrical piston valve
independently of said rocker.
13. In a rock drill, the combination with a cylinder, a piston, a valve chamber
having a cylindrical bore, a cylindrical piston valve adapted to reciprocate therein,
and admission and exhaust ports, of a rocker operated by the said piston to move
the valve at or near the end of a full stroke of the piston, and an independent valve
arranged in one of the exhaust ports, said valve being spring actuated in one
direction whereby same is normally held open, but adapted to be closed against
the tension of said spring when desired to close the said port independently of
the said rocker.
14. In a rock drill, the combination with a cylinder, a piston, and a valve for
controlling the admission and exhaust of the motive fluid thereto, of means
operated by the piston to move the valve at or near the end of a full stroke of
the piston, an elastic pressure controller, by the manipulation of which, pressure
is applied to move the valve intermediate of the full stroke of the piston, and
means for automatically returning the elastic pressure controller to its normal
inoperative position. :
15. The combination in a rock drill with a cylinder, a piston, a distributing
valve and valve gear for same, of a short stroke contrivance having means for
automatically throwing it out of operation when released.
16. The combination in a rock drill with a cylinder, a piston, a distributing
valve and valve gear for same, of a short stroke contrivance for same.
Dated this 1st day of December 1899.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.