Improvements in and connected with Valves for Percussive Rock Drills, Direct Acting Pumps, and Engines.
Year: 1896

page_text: Date of Application, 12th May, 1896
Complete Specification Left, 11th Feb., 1897-Accepted, 13th Mar., 1897
PROVISIONAL 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, Minin
Engineers, do hereby declare the nature of this invention to be as follows:-
The present invention relates to further improvements in the valve and passages
for controlling the movements of the piston of percussive rock drills, direct acting
pumps and engines, of the form described in the Specifications of our prior Patents
Nos. 8873 dated 9th June 1890, 11216, dated 18th July 1890, and 18284, dated
26th September 1894, in which such valve is itself actuated by the movements of the
piston in the main cylinder.
We still employ a main piston with a recess in its centre serving to connect the
passages leading to the valve cylinder with the main exhaust, and the valve has still
a passage at each end leading from the rear thereof to a point intermediate of its
length, while the valve has also still supplemental pistons working in cylinders with
a passage from the main supply which is controlled by the travel of the valve.
According to the present invention we now connect the cylinders in which the
supplemental valve pistons work by a suitable passage with the rear end of the valve
cylinder, which latter is also connected to the main piston cylinder so that it is opened
to exhaust when the recess in such piston is opposite same.
The action is as follows:-When the motive fluid passes from the main cylinder to
the rear of the valve piston by the passage leading to the rear of the latter it also
passes by the new passage to the rear of the supplemental valve piston and the valve
is reversed. The travel of the main piston has in its movement through the recess in
such piston connected the passage leading to the other end of the valve cylinder open
to exhaust, and consequently through the new passage referred to at a certain point
also put the cylinder of the other supplemental valve piston open to exhaust. The
reversal of the valve will of course have reversed the passages of the main piston
which will consequently begin its return travel, when the results above described will
take place at the opposite ends of the valve cylinder.
Dated this 12th day of May 1896.
ALLISON BROS.,
Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in and connected with Valves for Percussive Rook
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 further improvements in the valve and passages
for controlling the movements of the piston of percussive rock drills, direct acting
pumps and engines, of the form described in the Specification of our prior Patents

page_text: Nos. 8873 dated 9th June 1890, 11216, dated 18th July 1890, and 18284, dated
26th September 1894, in which such valve is itself actuated by the movements of
the piston in the main cylinder.
The accompanying drawing illustrates a suitable method of carrying this invention
into effect as applied to a percussive rock drill,
Fig. 1 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.
We still employ a main piston P.with a recess Zin its centre serving to
connect the passages D and I leading to the valve cylinder with the main exhaust E,
and the valve has still a passage B, B₁ at each end leading from the rear thereof
to a point intermediate of its length, while the valve P1, P2, has also still supple-
mental pistons M, N, working in cylinders with a passage X, X from the main
supply which is controlled by the travel of the valve. A, H are the passages
controlled by the travel of the main piston P, P, so as to govern the passage of the
motive fluid from the main cylinder to the rear of the valve pistons P1, P2,
through the passages B, B', in such pistons.
In Fig. 1 the valve P1, P2, has been shot over and the main piston P, P, is
about to begin its back stroke. The operation of the parts above described is the
same as that set forth in the specifications of our prior patents above referred to.
According to the present invention we now connect the cylinders in which the
supplemental valve pistons M, N work by a suitable passage a, a¹ with the rear end
of the valve cylinder, which latter is also connected to the main piston cylinder
through the passages D, I, so that it is opened to exhaust when the recess Z in the
main piston P, P, is opposite same.
The action is as follows:-When the motive fluid passes from the main cylinder
to the rear of the valve piston P2, by the passage B leading to the rear of the
latter it also passes by the new passage a¹ to the rear of the supplemental valve
piston N and the valve is reversed. The travel of the main piston P, P has in
its movement through the recess Z in such piston connected the passage leading
to the other end of the valve cylinder open to exhaust, and consequently through
the new passage a referred to at a certain point also put the cylinder of the other
supplemental valve piston M open to exhaust. The reversal of the valve P¹, P
will of course have reversed the passages of the main piston P, P, which will
consequently begin its return travel, when the results above described will take
place at the opposite ends of the valve cylinder.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be 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 reversing
the valve, while passages lead from the rear of each valve piston to the main
piston cylinder and the main piston has a recess or annular groove for placing the
rear of each of such valve pistons alternately open to exhaust, the combination
therewith of a passage connecting the rear of each valve piston with the rear of a
supplemental valve piston the movement of which in the valve cylinder controls
the supply and exhaust passages to the main piston cylinder, all substantially as
specified.
111
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3007
ALLISON BROS.,
Agents for the Applicants.