Improvements in Direct Acting Fluid Pressure Engines.
Year: 1898

page_text: Date of Application, 3rd May, 1898-Accepted, 4th June, 1898
COMPLETE SPECIFICATION.
Improvements in Direct Acting Fluid Pressure Engines.
I, ALBERT BALL, a citizen of the United States of America, residing at the corner
of Myrtle and Walnut Streets, in the Town of Claremont, County of Sullivan and
State of New Hampshire, United States of America, Draughtsman, 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 direct acting engines, such as are particularly applicable
to that class of coal or rock cutting machines in which a reciprocating cutter bar is
employed which is constructed to strike the coal and cut the same. These machines
being constructed on the principle of a direct acting engine, when the cutter bar fails
to strike the coal, such as when the machine is being adjusted to its work, or being
shifted on the runner's board while the machine is in motion, the tendency is to
increase the number of blows or strokes of the cutter-bar. The reciprocating under-
cutting machines strike a very hard blow, and if the pick happens to miss the coal
for any reason, the jar or shock on the operator is very severe, and more especially
so when the machine increases its number of blows per minute, as it will do when not
striking the coal and when there is nothing to regulate or control its speed.
It is now the general custom in this class of machines to cushion the blow of the
piston when the pick fails to strike the coal, by compressing the air in the front end
of the cylinder. This compression of the air, however, increases the speed of the
piston. It is in connection with this compression of the air that my invention is
particularly applicable.
The object of my invention, therefore, is to provide a direct-acting engine which
when applied to a coal cutting machine will regulate and control the movement of
the piston when the machine is not doing any work, and so relieve the wear and
tear on the machine, as well as the strain on the operator.
To these ends my invention comprises, generally stated, a cylinder with a piston
therein, suitable ports and valves controlling the same for causing the reciprocation
of said piston, an auxiliary valve controlling the admission of air, or steam, to one
end of said cylinder, and means for regulating the movement of said valve by the
cushioned air, whereby the said air holds said valve to its seat, and means for
gradually reducing the pressure of said cushioned air on said valve.
In the accompanying drawing, Figure 1 is a longitudinal sectional view of a portion
of an engine with my invention applied thereto; Figure 2 is an enlarged detail of
the check-valve; Figure 3 is a modified form of my invention; Figure 4 is a vertical
section of the auxiliary valve and its stem.
While I will describe my invention with reference to its use in connection with that
class of coal cutting machines hereinbefore referred to, yet I do not wish to limit its
use to this particular machine, as there may be other machines to which it may be
found applicable.
The letter a designates a portion of a suitable cylinder, and b the piston adapted
to reciprocate therein. The piston rod c passes out through the front head d provided
with a suitable stuffing-box. Where the invention is to be applied to a coal cutting
machine, the piston rod will carry the pick at its outer end by means of which the
cutting is done.

page_text: The air or steam chest e is secured to the cylinder a and said chest contains the
main slide valve f which controls the inlet and outlet of air to the front end of
cylinder. As only the front end of cylinder is shown the letter h designates the inlet
port and i and the exhaust ports.
Located in the inlet port h is the check-valve k provided with the stem l. The
check-valve k rests on the valve seat k¹. A cup m of leather or other suitable
inaterial is interposed between the valve k and the head of the stem l.
The stem passes up within a chamber n formed in the nut o which is threaded
into the cylinder a. This nut o has a cap r threaded into it, said cap having a
guide-way therein to receive the upper end of the stem l. A spring s is interposed
between the cap r and the head of the stem for the purpose of closing the
check-valve more quickly and to overcome the friction of the leather cup m on the
walls of the chamber above the said valve.
A port is formed in the check-valve k, said port extending up through the
stemas clearly indicated in dotted lines, Figure 2. The upper end of the port t is
reduced in size so as to form a contracted opening t¹ which will tend to retard the
escape of the air from the chamber n.
The cap is notched as at r² to permit the air passing up through the stem to
enter the chamber n.
The
When my invention is applied to a coal cutting machine its operation is as follows:
Under ordinary circumstances in cutting coal with such a machine the pick at the
forward end of the piston rod strikes the coal. As long as the pick continues to
strike the coal, no compression of the air takes place in the front end of the cylinder
and live air passes freely under the check valve k and through the port h to operate
the piston. When, however, the pick fails to strike the coal for any reason, the
compression of the air takes place at the front end of cylinder. Highly compressed
air then passes through the port t in the valve k and stem l, said air entering through
the contracted opening into the chamber n. At the same time a certain amount
of air finds its way into the chamber n by its being forced around the cup m.
effect of the air in the chamber n under heavy pressure is to hold the check-valve k
closely to its seat and prevent the flow of live air through the port.h to the front end
of cylinder. Just as soon as the pressure of the air in the front end of cylinder
begins to decrease, as it does the moment the piston starts on its backward stroke,
the air confined within the chamber n begins to escape therefrom. Owing, however,
to the size of the contracted opening leading to the port t the escape of the
air is slow and gradual. It is of course apparent that the size of this opening t
regulates the rapidity with which the air escapes, and that the reduction in the speed
of the piston is dependent on the size of this opening. Until the pressure in the
chamber n decreases below that of the live air in the port h the check valve k will
remain closed, and the live air will be prevented from acting to force the piston back
on its backward stroke.
It is to be noted that while air can be forced up around the cup minto the
chamber m, yet the air from said chamber cannot escape around said cup, as the
pressure of air in said chamber will cause said cup to hug the walls of the chamber
and form a tight joint.
Just as soon as the air pressure in the chamber n has fallen below that of the live
air pressure, the live air will lift the check-valve and act on the piston.
4
4
It is apparent from the above that when the pick fails to strike the coal the speed
of the piston is reduced at once, so that if the machine was running normally at, for
instance, two hundred strokes per minute, if the pick failed to strike the coal, the 5
speed can be maintained at two hundred strokes, or instantly reduced to sixty
strokes, according to the rapidity with which the air is permitted to escape from the
chamber n.
This reduction in the speed of the piston when the pick is not striking the coal
greatly reduces the labor of handling the machine, as it may be adjusted to its work 5
when in motion, or may be shifted on the runner's board without jarring.the operator

page_text: severely. Besides this there is a saving in air and the wear and tear on the machine
is greatly reduced.
In Figure 3 I have illustrated a modified form of my invention. The parts in this
case are indicated by numerals. The numeral 4 designates the nut adapted to be
threaded into the cylinder; 5 the cap; 6 the chamber; 7 the recess formed in said
cap for the reception of the retaining valve 8 which has the stem 9 and the spring 10
encircling the same. This retaining valve 8 closes the opening 10ª at the upper end
of the stem 11 of the check-valve 12. This check-valve 12 has a port 13 which
extends through its stem. A small opening 14 is also formed in the stem bringing
the port 13 always into communication with the chainber 6. A spring 15 encircles
the stem 11. cup 16 is interposed between the valve 12 and the head 17 on said
stem.
In the operation of this modified form, when the pick fails to strike the coal, the
air in the same manner as before described is compressed at the front end of cylinder
and passes by the port 13 into the chamber 6. The retaining valve is raised so as
to allow the air to pass by the opening 10 into said chamber. A portion of the air
also finds its way by the opening 14 into said chamber. In the same manner as
before described, just as soon as the pressure at the front end of the cylinder begins
to decrease on the back stroke of the piston, the retaining valve 8 closes and the
only means of escape for the air held under pressure within the chamber 6 is
through the opening 14. The rapidity with which the air escapes from the
chamber 6, as before, regulates the time when the valve 12 will open to permit live air
to pass to the front end of cylinder.
The retaining valve 8 holds the air within the chamber and may be employed
where a large amount of air is required in the chamber to reduce the speed.
While I have described my invention where air is employed as a motive power,
yet steam or other motive power may be employed.
I do not wish to limit myself to the invention as illustrated, but wish to include
within its scope such changes and variations as may be made without departing
from the spirit of said invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim, is:
1. In a direct acting engine, the combination with a cylinder having inlet and
exhaust ports, of a main valve controlling same, a piston working in said cylinder,
an auxiliary valve located so as to, control the inflowing air to the front end of said
cylinder, and means for regulating the movement of said auxiliary valve by the
cushioned air, substantially as set forth.
2. In a direct acting engine, the combination with a cylinder having inlet and
exhaust ports, of a main valve controlling same, a piston working in said cylinder,
an auxiliary valve located so as to control the inflowing air to the front end of
said cylinder, said auxiliary valve having an air chamber back of same, and said
chamber communicating with said cylinder substantially as set forth.
3. In a direct acting engine, the combination with a cylinder having inlet and
exhaust ports, of a main valve controlling same, a piston working in said cylinder,
an auxiliary valve located so as to control the inflowing air to the front end of said
cylinder, said auxiliary valve having an air chamber back of same, said chamber
communicating with said cylinder, and means for reducing the pressure in said
chamber, substantially as set forth.
4. In a direct acting engine, the combination with a cylinder and a piston working
therein, of a check-valve controlling the inlet port of said cylinder, said valve having
an air chamber back of same, said check-valve having a port forming communication
between said cylinder and said chamber, substantially as set forth.
5. In a direct acting engine, the combination with a cylinder and a piston working
therein, of a check-valve controlling the inlet port of said cylinder, said valve
having an air chamber back of same, said check-valve having a port forming com-

page_text: munication between said cylinder and said chamber, and said port having a con-
tracted opening, substantially as set forth.
6. In a direct acting engine, the combination with a cylinder and a piston working
therein, of a check-valve controlling the inlet port of said cylinder, said valve
having an air chamber back of same, a stem, said valve having a port formed therein
and in the stem, said port forming communication between said cylinder and chamber,
substantially as set forth.
7. In a direct acting engine, the combination with a cylinder and a piston working
therein, of a check-valve controlling the inlet port of said cylinder, said valve having
an air chamber back of same, said chamber communication with said cylinder, and a
packing cup on said valve engaging the walls of said chamber, substantially as set
forth.
8. In a direct acting engine, the combination with a cylinder and a piston working
therein, of a check valve controlling the inlet port of said cylinder, said valve having
an air chamber back of same, said chamber communicating with said cylinder, and a
packing cup inserted between said valve and a head on the stem thereof and engaging
the walls of said chamber, substantially as set forth.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.