Improvements in and connected with Valves for Percussive Rock Drills, Direct Acting Pumps, and Engines.
Year: 1890

page_text: Date of Application, 9th June, 1890
Complete Specification Left, 9th Mar., 1891-Accepted, 6th June, 1891
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
Laurvig, in the Kingdom of Norway, Mining Engineers, do hereby declare the
nature of this invention to be as follows:-
Our invention relates to improvements in the class of air or steam moved piston
valves, and to a novel arrangement of passages for controlling the supply and
exhaust of steam or compressed air to the pistons which actuate the valve, whereby
all external connections, tappets, swellings on or hollow spaces in the piston rod are
dispensed with, and greater simplicity and efficiency obtained. These improve-
ments are applicable to percussive rock drills, direct acting pumps and engines
generally.
The motor is provided with a cylinder, a piston rod with piston head, and a valve
of ordinary construction. The valve is arranged between small pistons respectively
working in small cylinders formed in opposite ends of the valve chest.
In carrying out our improvements in each of the small pistons which actuate the
valve we form passages, and annular grooves connected with these passages are
cut on each valve piston. Further in addition to the ordinary supply and exhaust
ports we construct four other passages in the main cylinder, two of which passages
serve through the annular grooves and passages in the small valve pistons to con-
nect the cylinders in which these pistons work with the main cylinder, whilst the
other two passages connect the said small cylinders direct to the opposite ends of
the main cylinder respectively. The annular grooves in communication with the
passages formed in the valve pistons to connect these to their respective passages
leading to the main cylinder, are so arranged that when the one is open to the
supply from the main cylinder the other is cut off; and the passages connecting
the small cylinders in which the valve pistons work with the opposite ends of the
main cylinder are so arranged that the passage in communication with the live air
or steam in the main cylinder is closed by its valve piston whilst the other passage
is uncovered and the valve piston cylinder with which it is in connection thus put
in communication, through the main cylinder, with the exhaust.
Dated this 9th day of June 1890.
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
Laurvig, in the Kingdom of Norway, 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:-
Our invention relates to improvements in the class of air or steam moved piston
valves, and to a novel arrangement of passages for controlling the supply and
exhaust of steam or compressed air to the pistons which actuate the valve, whereby
all external connections, tappets, swellings on or hollow spaces in the piston rod
are dispensed with, and greater simplicity and efficiency obtained. These im-
provements are applicable to percussive rock drills; direct acting pumps and engines
generally

page_text: The invention as applied to a percussive rock drill is illustrated in the accom
panying drawings, in which
Fig.
is a longitudinal section of a rock drill embodying our invention.
Fig. 2 is a plan view thereof with the valve chest removed.
Fig. 3is a plan view of the valve chest.
Eig. 4 is a transverse section on the line A, B, Fig. 1.
Fig. 5 is a transverse section on the line C, D, Fig. 1.
Fig. 6. is a longitudinal section of a rock drill showing a slight modification of
our invention.
Fig. 7 is a plan view of Fig. 6, with the valve chest removed.
Fig. 8 is a transverse section on line E, F, Fig. 6.
Fig. 9 is a transverse section on line G, H, Fig. 6.
Like letters indicate corresponding parts throughout the drawings.
C is the cylinder with piston P and piston rod R of ordinary construction:
P and P are small pistons to actuate the valve V, and which pistons work respec-
tively in small cylinders C', C², formed in opposite ends of the valve chest.
Referring to Figs. 1 to 5 inclusive of the drawings, it will be seen that in
carrying out our improvements, in the interior and from the rear of the small
pistons P1, P2, which actuate the valve V, we construct the passages B', B, and
connect these passages to annular grooves and G formed on the exterior of each
valve piston. Further, in addition to the ordinary supply ports J and K and
exhaust passage E, we construct four other passages I), A, H, I, in the main
cylinder C, two of which A and H, through the annular grooves F and G and
passages B and B, connect the valve piston cylinders C and C2, with the main
cylinder C, whilst the other two passages D and I connect the said valve piston
cylinders Cand C, direct to the opposite ends of the main cylinder respectively.
The annular grooves F and G formed on the exterior of the valve pistons P
and P2 to connect the passages B' and B, formed in the said pistons, with the
passages A and H leading to main cylinder C, are so arranged that when one of
such annular grooves is open to supply from the main cylinder the other annular
groove is cut off therefrom, and the passages I and D connecting the valve piston
cylinders C and C', in which the valve pistons P2 and P' work, with the opposite
ends of the main cylinder C respectively, are so arranged that they are alternately
opened and closed by the travel of the valve pistons P and P¹; and, further, when
one passage (or D) is open to the live air or steam in the main cylinder C, the
other is in communication, through the opposite end of the main cylinder, with the
exhaust E.
The action is as follows:--
The piston P having arrived at its full backward stroke, air or steam is admitted
from the main cylinder C, through passage H, annular groove G and passage B,
to the rear of valve piston P, and causes the forward movement of the valve pistons
and valve. In its travel piston P² covers passage H, and uncovers passage I con-
necting the lower end of main cylinder C and valve piston cylinder C2, thus
maintaining full pressure of air or steam in the valve cylinder C2. During this
movement the valve cylinder C' is open to exhaust through passage D, the top end
of main cylinder C, port K and exhaust passage E, until piston Pin its travel
covers passage D, when annular groove opens to passage A, and communication
with the bottom end of main cylinder C and exhaust E kept up, for at the same
time, the movement of the valve V will have put the space below main piston P
open to exhaust through passages.J and E. When annular groove F reaches the
passage A, the valve cylinders C and C₁ are both in communication with the same
(the lower) end of the main cylinder C, the former through passage I and the
latter through passage B', annular groove F and passage A, whereby the pressures
on the valve pistons P2 and P. are brought into equilibrium, whereupon the
remaining travel of the valve is effected by the momentum acquired by the valve
pistons. The valve will now have uncovered port K, so that the steam or air in
the valve chest will pass to the rear of piston P and effect the forward stroke. On

page_text: the completion of the full forward stroke, passage A is opened to the live air or
steam in the main cylinder C, which air or steam flows through such passage, and
the annular groove F and passage B', to the rear of piston P, causing the return
movement of the valve pistons and valve. In its travel piston P now covers
passage A, and uncovers passage D connecting cylinder C¹ with the top end of the
main cylinder C, thereby maintaining full pressure of air or steam in the valve
cylinder C. The rear of valve piston P is open to exhaust through passage I,
the top end of main cylinder C, and port J and exhaust E, until piston P2 covers
passage I, when communication with the main cylinder C is kept through annular
groove G opening to passage H, whereupon the pressures on the valve pistons P¹
and P are brought into equilibrium, and the remaining travel of the valve effected
by the momentum acquired by the valve pistons, as on the outward stroke. At the
same time the movement of the valve V will have put the space above the main
piston open to the exhaust through passages K and E, and uncovered port J, so
that air or steam in the valve chest will pass to the underside of the main
piston P, and so effect the backward stroke, when the action will be repeated as
described.
:
The arrangement of the passages H, A, and I, D, may (as shown in Figs. 6 to 9
inclusive of the drawings) be reversed, that is to say, the passages H and A pro-
ceeding from the main cylinder C may be connected with the opposite valve piston
cylinders C and C2, by the annular grooves F and G and passages B and B in the
valve pistons P, P₁, whilst the passages I and D connect the valve cylinders C
and C respectively to the same end of main cylinder C, either through the supply
and exhaust ports J and K, or by independent passages. In this arrangement
the valve pistons P1 and P2 and the valve V are caused to reciprocate in a precisely
similar manner to that above described.
In the arrangements described a rod S projecting through one end of the valve
chest is provided to enable the valve to be pushed over when necessary in starting
the engine.
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 :-
1. The combination with the main cylinder of a percussive rock drill or other
motor having a reciprocating piston and a valve carried between two pistons working
in cylinders in the valve chest and controlling the supply and exhaust of the motive
fluid to and from such main cylinder, of a passage formed in each valve piston and
leading from the rear thereof to a point intermediate of its length, and two passages
in each valve piston cylinder controlled by the movement of the valve piston
therein, one of such passages from each valve piston cylinder leading to the same
end of, and the other to the opposite end of, the main cylinder, so as to be controlled
by the reciprocation of the main piston, substantially as specified.
2. The improved arrangement of passages for actuating and controlling the
movements of the valve of reciprocating engines, substantially as described and
shown.
Dated this 9th day of March 1901
ALLISON BROS.,
Agents for the Applicants.