Improvements in and connected with Valves for Percussive Rock Drills, Direct Acting Pumps and Engines
Year: 1894

page_text: Date of Application, 26th Sept., 1894
Complete Specification Left, 26th June, 1895-Accepted, 10th Aug., 1895
TRUVIDIONALNI POTITIA
Improvements in and connected with Valves for Percussive Rock
Drills, Direct Acting Pumps and Engines.
We, ALBERT WILLIAMS DAW, and ZACHARIAS WILLIAMS Daw, both of
Mansion House Chambers, No. 11 Queen Victoria Street, in the City of London,
Mining Engineers, do hereby declare the nature of this invention to be as
follows:-
The present invention relates to improvements in the valve and passages for
controlling the supply and exhaust to the cylinder of the main piston of
reciprocating engines, such valve being of the form and operated in the manner
fully set forth in the Specification of our prior Patents Nos. 8873 dated 9th June
1890 and 11216 dated 18th July 1890, the action of such valve being effected by
the main piston in its travel controlling passages leading from the main cylinder to
the opposite ends of the cylinder in which the valve works, but the additional
passages connecting the ends of the valve cylinder with the ends of the main piston
cylinder will not be necessary.
According to the present invention in addition to the passages above referred to
we provide other passages also leading from the opposite ends of such valve
cylinder to the main piston cylinder, but in a different position in the length of the
latter to the existing passages, and also a passage or passages leading from the
main exhaust of the engine into the main cylinder, and we provide an annular
groove in the main piston of sufficient length to enable the piston in its travel to
alternately connect one of the new passages leading from the valve cylinder to the
passage or passages leading from the main exhaust, so that the opposite ends of
the valve cylinder will thus be placed open to exhaust alternately, while the other
is shut off therefrom, and further the new passages are so arranged with regard to
the length of the piston and the annular groove therein and the travel of such
piston that the exhaust passage from the main cylinder to one end of the valve
cylinder is always closed by the travel of the main piston before such piston opens
the supply passage from the main cylinder to the same end of the valve cylinder
for the purpose of reversing the valve and consequently the supply and exhaust of
the main cylinder.
Dated this 26th days of Santamber 1894
ALLISON BROS.,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in and connected with Valves for Percussive Rock
Drills, Direct Acting Pumps and Engines.
We, ALBERT WILLIAMS DAW, and ZACHARIAS WILLIAMS DAW, both of
Mansion House Chambers, No. 11 Queen Victoria Street, in the City of London,
Mining Engineers, 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 :-
The present invention relates to improvements in the valve and passages for
controlling the supply and exhaust to the cylinder of the main piston of

page_text: reciprocating engines, such valve being of the form and operated in the manner
fully set forth in the Specifications of our prior Patents Nos. 8873 dated 9th June
1890 and 11216 dated 18th July 1890, the action of such valve being effected by
the main piston in its travel controlling passages leading from the main cylinder to
the opposite ends of the cylinder in which the valve works, but the additional
passages connecting the ends of the valve cylinder with the ends of the main piston
cylinder will not be necessary.
According to the present invention in addition to the passages above referred to
we provide other passages also leading from the opposite ends of such valve
cylinder to the main piston cylinder, but in a different position in the length of the
latter to the existing passages, and also a passage or passages leading from the
main exhaust of the engine into the main cylinder, and we provide an annular
groove in the main piston of sufficient length to enable the piston in its travel to
alternately connect one of the new passages leading from the valve cylinder to the
passage or passages leading from the main exhaust, so that the opposite ends of the
valve cylinder will thus be placed open to exhaust alternately, while the other is
shut off therefrom, and further the new passages are so arranged with regard to
the length of the piston and the annular groove therein and the travel of such
piston that the exhaust passage from the main cylinder to one end of the valve
cylinder is always closed by the travel of the main piston before such piston opens
the supply passage from the main cylinder to the same end of the valve cylinder
for the purpose of reversing the valve and consequently the supply and exhaust of
the main cylinder.
The accompanying drawing illustrates a suitable method of carrying the invention
into effect as applied to a percussive rock drill,
Fig. being a longitudinal section through the main cylinder and the valve
cylinder of such drill.
Fig. 2 a plan view of the main cylinder with the valve cylinder removed, and
Fig. 3 a horizontal section through the valve cylinder.
C is the main cylinder, and P the piston which reciprocates therein, the end of
the rod R of such piston being fitted with the ordinary drilling tool. J, K are the
supply and exhaust passages leading to the opposite ends of the main cylinder,
while E is the exhaust port and X the main supply, which are alternately cou-
nected to the passages J, K by the annular grooves V, V in the main valve.
A, H are the two passages leading from the main cylinder C to the opposite ends
of the valve cylinder in which the pistons P1, P2 of the main valve work, and which
are controlled by the movement of the main piston P working in such cylinder C.
The pistons P1, P2 are formed with annular grooves F, G, from which
passages B', B lead to the back of each piston, so that when one or other of same
is opposite to one of the passages A, H, and the latter is uncovered by piston P in
its travel in cylinder C, the motive fluid behind such piston P will pass behind one
of the main valve pistons P1, P2 and so reverse the valve, and thus reverse the
supply and exhaust connections of the main cylinder C.
described and their operation are the same as those set forth in the Specifications
The parts above
of our prior Patents No. 8873 A.D. 1890, and 11216 A.D. 1890, above referred to.
In order to place the outer end of the cylinders in which the valve pistons P1, P2,
work, alternately open to exhaust we form passages D, I, leading from the outer
end of each of such cylinders to the main cylinder and in such positions that
same are by the travel of the main piston P in the latter alternately connected
with the annular groove Z formed in such main piston, while such annular groove
is always open to a passage Y leading to the main exhaust. In the arrangement
shown in the drawing the exhaust passage Y has two openings into the main
cylinder C, each serving to connect one of the piston valve cylinders with the
exhaust through the annular groove Z in the main piston P, but by using a longer
main piston and making the groove Z therein longer the passage Y might have a
single opening only into the main cylinder which the groove Z would alternately
connect with one of the valve piston cylinders.

page_text: In the position shown in Fig. 1 of the drawings the main piston P is at the
end of its backward stroke and valve V has been shot over so as to connect
passage K to supply, and passage J to exhaust, while the rear of the valve
cylinder in which valve piston P' works is also open to exhaust through passage I,
groove Z in main piston P, and exhaust passage Y. The main piston P then
begins its return stroke until it opens passage H and permits the motive fluid
to pass to the rear of valve piston P through annular groove G and passage B
in such piston, whereby the valve is reversed, thus opening the rear of inain
piston P to exhaust and the front of same to supply, while the rear of valve
piston P will then be open to exhaust through passages D and Y and aunular
groove Z in main piston P, the rear of valve piston P2 having at the same
time been cut off from exhaust by the movement of the main piston. The
main piston then completes its outward stroke and begins its return, the effect
being to open the rear of valve piston P¹ to supply through passage A, annular
groove F, and passage B', while at same time the rear of valve piston P2 has
been opened to exhaust through passages I, Y, and annular groove Z in main
piston P, while the rear of valve piston P¹ has been cut off from exhaust. The
valve will consequently be reversed, thus opening the rear of main piston P to
supply, and the front of same to exhaust, and at same time opening the rear
of valve piston P2 to exhaust, and shutting off the rear of valve piston P¹ from
exhaust. The inward stroke of the main piston will then be completed and the
operation described repeated.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to he performed, we declare that what
we claim is :-
In percussive rock drills or other motors having a reciprocating piston and
a valve actuated by pistons working in cylinders formed in the valve chest, and
having passages leading therefrom into the main cylinder so that the reciprocation
of the main piston in the latter will open such passages alternately to supply, for
the purpose of reversing the valve, the combination therewith of passages leading
from the rear of each valve piston to the main piston cylinder and of a passage
leading from the latter to the main exhaust, together with an annular groove
formed in the main piston so as to place the rear of each piston valve alternately
open to exhaust, all substantially as described.
Dated this 26th day of June 1895.
ALLISON BROS.,
Agents for the Applicants.