An Improved Automatic Plug-cock Valve.
Year: 1889

page_text: Date of Application, 14th May, 1889
Complete Specification Left, 10th Oct., 1889-Accepted, 21st Dec., 188)
PROVISIONAL SPECIFICATION.
[Communicated from abroad by JESSE FAIRFIELD CARPENTER, of No. 19, Leipziger
Platz, Berlin, in the Empire of Germany, Engineer.]
An Improved Automatic Plug-cock Valve.
I, HENRY HARINGTON LEIGH, Fel. Inst. P.A., Assoc. M. Inst. C.E., of No. 22,
Southampton Buildings, Chancery Lane, W.C., practising as Phillips & Leigh,
Engineers and Patent Agents, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in automatic plug cock valves for working,
by means of either compressed or rarefied air, switches, signals, or other mechanisms,
situated at considerable distances from the point of operation.
In carrying my invention into effect, I provide a suitable case in which a flexible
diaphragm, or its equivalent, is adapted to be moved in either of two directions, by
differentiating the pressure of the atmospheres on its respective sides.
Suitable pipe
connections are established between the said sides and two volumes of air, and proper
means for regulating the pressures therein are also provided.
The communication between the said volumes of air is intercepted by a duplex cock
plug. The two plugs are axially aligned, and engage with each other by means of
projections and notches, so that the motion of the larger is communicated to the
smaller so soon as a certain space, or play, in the said engagement shall have been
passed.
A suitable series of ports is formed through the said plugs for the purpose of
establishing and regulating the communication between two volumes of air above
mentioned, and also between either of them and the outer air. These ports are so
arranged in respect of their position that more than one of them can establish com-
munication in a given direction at one time, and so allow the air to pass more rapidly.
The cock plugs are operated by means of a link and lever mechanism of special and
distinctive principle and construction.
The link connects the diaphragm before mentioned to the lever mechanism in such
a way that the latter shall be moved on its fulcrum so soon as any difference between
the air pressures acting upon the diaphragm shall be established."
If the fulcrum of the lever be a constant one-the point of connection between the
link and the lever being constant-it follows that the leverage upon the plug will also
be constant.
Now, my invention provides means whereby the amount of leverage shall be auto-
matically increased or diminished as circumstances may require.
My improved lever mechanism consists of a lever, or arm, fast on the larger cock
plug. On this arm is pivotted a second lever provided with two horns at the end next
the cock.
These horns are adapted to engage with the first mentioned lever, or arm, at certain
portions of the travel of the link, so that both levers act practically as one lever
continuous from the point of connection between the link and the lever mechanism,―
i.e., the link-end,-and the axis of the cock-plug.
Supposing that at the moment when the link begins to move, the horn next to the
diaphragm is in contact with the plug, then will the leverage be in proportion to the
distance between the link-end and the plug axis; whereas if the horns are away from
the plug the leverage will be in proportion to the distance between the link-end and
the pivot between the two levers.
Further, I provide two stops or fixed points to limit the motion of the horned lever.
These stops are on the side of the link-end opposite to the plug; and when the lever
contacts with the stop, the horn is moved away from the plug, and the fulcrum of the

page_text: horned lever transferred to the said stop with a consequent modification-increase if
the various centres be so arranged-of the leverage exerted upon the cock plug by the
motion of the link.
The present invention is capable of numerous applications and I will now describe
one of them for which its excellencies and capabilities especially adapt it, viz., the
actuation of railway brakes.
Assuming that the working agent is compressed air a donkey pump on the engine
forces air into a reservoir, from which the pressure passes through the main pipe
extending for the whole length of the train, to a valve, brake-reservoir, and set of
brake-mechanism on each carriage.
When the pressure in the main pipe is exhausted, that underneath the diaphragm
will follow suit; but the pressure in the brake reservoir, which is also that obtaining
above the diaphragm, cannot exhaust so rapidly through the cock plug, the size of the
port being arranged for that purpose, and relatively exceedingly small.
The excess pressure obtaining above the diaphragm forces the laiter down. It
carries the link with it, and the cock-plug is moved accordingly by means of the
link-and-lever mechanism already described, until a communication through the cock-
plug has been established between the brake-reservoir and the brake-cylinder, with the
result that the brake is applied; the several stages of the process being as follows,
and of course according to the position of the ports in the plug relatively to that of
the ports in the body of the cock.
1. Brakes off.
2. Main pipe exhausted on each carriage to either brake-cylinder or the atmosphere.
3. Brakes half on.
4. Brakes held on.
5. Brakes full on.
It is to be borne in mind that stage No. 1, i.e. of brakes off, is the normal one, so to
speak and that stage No. 2-exhausting the main pipe-is really the leading one in
:
my invention.
It takes precedence in point of time of the others; and I attach much
importance to its position in the order of the four stages which together make up the
cycle of operation.
Dated this 14th day of May 1889
Dated this 14th day of May 1889
HENRY H. LEIGH.
COMPLETE SPECIFICATION.
An Improved Automatic Plug-cock Valve.
I, HENRY HARINGTON LEIGH, Fel. Inst. P.A., Assoc. M. Inst. C.E., of No. 22,
Southampton Buildings, Chancery Lane, W.C., practising as Phillips & Leigh,
Engineers and Patent Agents, do hereby declare the nature of this invention and in
wha: 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 automatic plug-cock valves for working,
by means of either compressed or rarefied air, switches, signals, or other mechanisms
situated at considerable distances from the point of operation.
In carrying my invention into effect, I provide a suitable case in which a flexible
diaphragm, or its equivalent, is adapted to be moved in either of two directions, by
differentiating the pressure of the atmospheres on its respective sides. Suitable pipe
'connections are established between the said sides and the two volumes of air, and
proper means for regulating the pressures therein are also provided.
The communication between the said volumes of air is intercepted by a duplex cock
plug. The two plugs are axially aligned, and engage with each other by means of
projections and notches, so that the notion of the larger is communicated to the
smaller, so soon as a certain space, or play, in the said engagement shall have
been passed.
A suitable series of ports is formed through the said plugs for the purpose of
establishing and regulating the communication between the two volumes of air

page_text: above mentioned, and also between either of them and the outer air. These ports are
so arranged, in respect of their positions, that more than one of them can ostablish
communication, in a given direction, at one time; and so allow the air to pass more
rapidly.
The cock plugs are operated by means of a link-and-lever mechanism of special and
distinctive principle and construction.
The link connects the diaphragm before mentioned to the lever mechanism in such
a way, that the latter shall be moved on its fulcrum so soon as any difference between
the air pressures acting upon the diaphragm shall be established.
If the fulcrum of the lever be a constant one-the point of connection between the
link and the lever being constant-it follows that the leverage upon the plug will also
be constant.
Now, my invention provides means whereby the amount of loverage shall be
automatically increased or diminished as circumstances may require.
My improved lever mechanism consists of a lever, or arm, fast on the larger cock-
plug. On this arm is pivotted a second lever provided with two horns at the end
next the cock.
These horns are adapted to engage with the first mentioned lever, or arm, at certain
portions of the travel of the link, so that both levers act practically as one lever
continuous from the point of connection between the link and the lever mechanism,―
i.e., the link-end,-to the axis of the cock-plug.
Supposing that, at the moment when the link begins to move, the horn next to the
diaphragm is in contact with the plug, then will the leverage be in proportion to the
distance between the link-end and the plug-axis; whereas, if the horns are away from
the plug, the leverage will be in proportion to the distance between the link-end and
the pivot between the two levers.
Further, I provide two stops or fixed points to limit the motion of the horned lever.
These stops are on the side of the link end opposite to the plug, and when the lever
contacts with the stop, the horn is moved away from the plug, and the fulcrum of
the horned lever transferred to a stop with a consequent modification (increase, if
the various centres be so arranged) of the leverage exerted upon the cock-plug by
the motion of the link.
The present invention is capable of numerous applications, as already stated in the
opening paragraph of this specification; but that the details of its mechanism,
operation, and application, may be thoroughly understood, I will now proceed to
describe the invention as applied to the actuation of a railway-brake, but it is to be
distinctly understood that the application described and illustrated is given only as an
illustration of the nature, construction, and operation of my invention, and not as
defining its uses.
Referring then to the accompanying drawings which are to be taken as part of this
specification, and read therewith,
Fig. 1 is a sectional elevation; and illustrates the relative positions of the parts
when the invention is at rest, i.e., when equal pressures obtain upon both sides of the
diaphragm.
•
Fig. 2 is a vertical section of the small plug-cock and barrel when the diaphragm
is in the position illustrated by the dotted lines of Fig 1.
Fig. 3 is a plan corresponding with Fig. 1.
Fig. 4 is an illustration of the relative positions of the two plugs and the link-and
lever-mechanism when the pressure in the supply pipe has been reduced.
Fig. 5 is an illustration of the relative positions of the two plugs and the link-and-
lever mechanism when the ports between the pressure-reservoir and the brake-
cylinder are in communication, i.e., brake half on.
The dotted lines of Fig. 1 illustrate the next position, i.e., when fresh pressure from
the supply is being sent through the cock into the brake-cylinder.
Fig. 6 illustrates the position when all the ports of the cock are shut off from the
air-supply, as well as from all exhaust ports.
The sections of Figs. 4, 5, and 6 are taken in respectively corresponding planes.

page_text: Fig. 7 is a sectional elevation on the line A-B of Fig. 1, assuming the plug to be
in the position illustrated in Fig. 5.
Fig. 8 is a plan taken on the line C-D of Fig. 7.
E is the air-tight case containing the operative parts of my invention. F is the
air-pressure supply. G is the pipe to the pressure-reservoir; and H, the pipe from
the brake-cylinder.
The donkey engine and exhaust cock for respectively creating or exhausting the
air-pressure, the pressure-reservoir, and the brake-cylinder are too well known as parts
of an air-pressure mechanism to require illustration here; and, for that reason, they
are omitted from the figures.
E is the port leading into I, the diaphragm-chamber, to the underside of the
diaphragm J. The upper cavity K of the case is in free communication with the
top of the diaphragm.
L is the cock-barrel situated where the members F, G, H, and K approach each
other. It is provided with a duplex plug, consisting of a, the larger, and b, the
smaller, plug. It will be noticed that the ways a¹ of the larger plug are formed
in the sides thereof, instead of through it.
There are five ports formed in the barrel L, communicating with the cock-ways a¹
as follows: e is the air-pressure supply-port; f, the port to the pressure-reservoir;
g, the port to the brake-cylinder; the exhaust port from the said cylinder to the
air; and i, the exhaust port from the air-pressure supply F down round the small
plug to the brake-cylinder through the port H, or (when the cock is in the
necessary position) out through the ports in the plug and cock-barrel to the
outer air. In other words, the pressure supply may be exhausted either into the brake-
cylinder or to the outer air.
The two plugs a and b engage with each other by means of projections a³, 12. But
the notches in the plugs which receive the respective projections are wider than the
said projections, as shewn in Figs. 7 and 8, so that the larger plug a does not
engage with the smaller, until the intervening space between the projections has been
passed.
The motion of the diaphragm J in either direction is communicated to the plug a
by a link-and-lever mechanism of special construction.
M is the link fast to the diaphragm N is a lever fast upon the head of the larger
plug a.
O is a second lever pivotted at o to the lever N, and at p to the link M. It is
provided with two horns o¹, o³, adapted to engage alternately with the head of the
plug. P, P are two stops, or fixed points, provided to limit the travel of the end o³
of the lever O. Their effect and the changes obtaining in the compound lever NO
during one travel of the diaphragm are clearly illustrated in Figs. 1, 4, 5, and 6.
The operation of my invention constructed and applied as illustrated for the purpose
of applying the brake is as follows.
All the parts of the apparatus, including the air-pressure supply, the pressure-
reservoir, and the brake-cylinder, having been filled with air at an even pressure
throughout, and the diaphragm and link-and-lever mechanism being in the position
illustrated by the full lines of Fig. 1; the pressure in the main supply pipe is exhausted.
The pressures on both sides of the diaphragm begin to follow suit, but as that in the
chamber K is throttled in its passage through the ports fand e, it exerts a practical
pressure upon the diaphragm J, sufficient to drive it downwards, turning the plug a
round into the position illustrated in Fig. 4 which shews all exhaust from the
chamber K stopped.
The continued descent of the link moves both the plugs a and b into the position
illustrated in Fig. 5, when the pressure from the pressure-reservoir enters through the
ports and g into the brake-cylinder.
The horn o' is next brought to bear upon the plug-head in consequence of the lever
end of having contacted with the stop P₁. Both plugs are moved round into the
position illustrated by the dotted lines in Fig. 1, and by Fig. 2; the ports fg con-
necting G and H, and the ports e i connecting F and H, being then full open.

page_text: The raising of the diaphragm effected by pumping more pressure into the chamber K
from the engine turns the plugs into the position illustrated in Fig. 6 which
shews the port g entirely shut off from all communication with either pressure-supply
or exhaust.
It is obvious that the application of my invention to the actuation of other than
brake-mechanisms will be substantially the same as described above with reference to
the accompanying drawings; such modifications of a complete brake-mechanism as
may be necessary will be outside the present invention and of common knowledge.
Also will it be clear that I may actuate my invention by rarefied instead of com-
pressed air without departing from the scope thereof.
It is to be borne in mind that the first of the series of stages, viz., the one
illustrated by the full lines of Fig. 1 is the normal one, so to speak, and that it
is only when the normal pressure obtaining in the main is exhausted that the
second stage, that illustrated in Fig. 4, which is really the leading one in my
invention, is reached. It takes precedence in point of time of the others, and I attach
much importance to its position in the order of the four stages-the one last
mentioned and the three subsequent ones-which together make up the cycle of
operation.
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. The combination with a diaphragm or its equivalent subjected to opposing
pressures and adapted to be moved by any differentiation thereof, of a link-and-lever
mechanism endowed with a variable fulcruin whereby its practical effect or the power
required to operate it at any given moment may be modified by a readjustment of
the position of the said fulcrum, as set forth.
2. The combination with a cock-barrel and a set of ports of two cock-plugs
axially aligned and adapted to engage with each other by projections and notches, as
set forth.
3. The combination with a diaphragm or its equivalent subjected to opposing
pressures and adapted to be moved by any differentiation thereof, of a link and lever
mechanism endowed with a variable fulcrum, and two cock-plugs axially aligned
within a barrel common to both and provided with a series of ports, the said plugs
adapted to engage with each other by projections and notches as set forth.
Dated this 10th day of October 1889
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, W.C., Agents for the Applicant.