IMPROVEMENTS IN AIR BRAKES AND IN EJECTORS TO BE USED THEREWITH, AND WHICH ARE ALSO APPLICABLE TO OTHER SIMILAR PURPOSES
Year: 1876

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
AIR BRAKES AND IN EJECTORS TO BE USED THEREWITH, AND WHICH ARE
ALSO APPLICABLE TO OTHER SIMILAR PURPOSES." A communication from
abroad by the Empire Vacuum Brake Company, of New York, in the United
States of America.
Scaled the 30th June 1876, and dated the 11th April 1876.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 11th April 1876.
USED
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN AIR BRAKES AND IN EJECTORS TO BE
THEREWITH, AND WHICH ARE ALSO APPLICABLE TO OTHER SIMILAR PURPOSES." A
communication from abroad by the Empire Vacuum Brake Company, of New
York, in the United States of America.
This Invention relates more particularly to the pistons and cylinders of air brakes
and to ejectors to be used for exhausting the air from such cylinders, which ejectors
are also applicable to other similar purposes.
The brake apparatus consists of a vacuum cylinder containing two pistons, the
rods of which extend out through the heads of the said chamber in opposite
directions and connect with the brake levers of a railway carriage in combination
with a pipe which enters the vacuum cylinder at a point between the two pistons,
and which connects with an ejector or steam nozzle secured to or connected with
the locomotive boiler in such a manner that by admitting steam to the said ejector
the air from the vacuum cylinder is exhausted, and by the action of the atmosphere
on the two pistons in the said vacuum cylinder the brakes are simultaneously
applied to all the wheels of the carriage. Each of the pistons in the vacuum
cylinder may be constructed with 2 heads and an intermediate air space com-
municating through a channel in the piston rod with the exhaust space of the
cylinder, while the packings of the said heads are composed of rings of leather or
other flexible material which project beyond the outer surfaces of the heads so that
by the combined action of the two heads the intermediate air space and the pro-
jecting packing rings leakage of air past the piston is prevented, and at the same.
[Price Gd.]

page_text: time comparatively little power is required to move the piston in the vacuum
cylinder. Each of the pistons may, however, consist of a single head if preferred.
The vacuum cylinder may either be composed of metal, or it may be constructed
of blocks or pieces of wood of suitable shape and thickness placed one over the other
so that the grain or structure of each piece shall be at right angles to the grain or
structure of the preceding piece. When the latter construction is adopted these
pieces are held in place by any suitable adhesive substance and firmly bolted together
by bolts running through the structure and secured by a nut at each end. By
means of these arrangements the tendency of the material to expand or contract is
counteracted, and the form of the cylinder in which the piston heads travel is
preserved without substantial change under the various conditions of dryness and
moisture, and of heat and cold.
By the use of a wooden cylinder and a wooden piston head with leather packing
constructed in the manner herein-before described the friction is much less than in
a cylinder of iron or other metal, and the peculiar manner of packing the piston
head herein-before described avoids friction, except at the moment when the pressure
of the atmosphere against the partial vacuum commences, when the vacuum is
destroyed the friction is also relieved, and the piston head is moved back to its
proper position by the use of a trifling amount of power.
In constructing the cylinder pieces of suitable wood well seasoned of, say, about
an inch in thickness, are cut from planks with the grain running lengthwise. As
such planks are usually sawed the surfaces of these pieces are made as level and
smooth as practicable; a sufficient number of the pieces are then glued together
with their grain running in opposite directions, and when the whole mass is
thoroughly dried the interior is bored out of suitable size for the reception of the
piston head.
The interior is carefully polished, care being taken to preserve
uniformity in the diameter for the entire length. After the piston heads have
been fitted with their packing, and the cylinder has been completed by bolting it
from end to end and closing the ends, and before the cylinder is applied to the
carriage, the piston heads are worked backwards and forwards in the cylinder by
any suitable power for several hours, and until the piston heads and their packing
have worked away or adjusted themselves to any small inequalities in the interior
of the cylinder.
The ejector, according to one modification, consists of a steam nozzle provided
with a conical spout situate in a line with the exhaust pipe, and which spout fits
into the mouth piece of the nozzle, leaving between its outer surface and the inner
surface of the said mouth piece an annular space communicating with the steam
supply pipe in such a manner that steam admitted through the said supply pipe
rushes out through the annular space between the spout and mouth piece and by
the current of steam thus created the air in the spout and in the exhaust pipe is
rarefied.
The conical spout is secured in position by means of a screw thread, or other
equivalent means, so that it can be moved in or out, and that the annular space
between the said spout and the mouth piece can be regulated, the mouth piece
being fitted into a socket formed in a flange on the body of the nozzle, so
that access can be had to the conical spout, and the annular space between the
spout and the mouth piece can be adjusted without disturbing the connecting
pipes.
The steam pipe and the air pipe are arranged so as to produce a more direct
and powerful action of the steami at the outlet of the air pipe than has heretofore
been attained. The air pipe at its outlet is completely surrounded by the steam
pipe, which projects beyond the mouth of the air pipe, and when the steam is intro-
duced the column of air at the outlet of the air pipe will be completely surrounded
by a sheet of steam.
According to another modification the air pipe leads by a gentle curve from the

page_text: union with the steam pipe to the vacuum chamber in the cylinder or other vessel,
and the steam pipe by a like curve leads to the boiler. This improvement thus
avoids an angle both in the steam pipe and the air pipe, and the loss of power
consequent thereon.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 11th
October 1876.
man.
JOIN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the of Middlesex, Gentle-
"IMPROVEMENTS IN AIR BRAKES AND IN EJECTORS TO BE USED THEREWITH,
AND WHICH ARE ALSO APPLICABLE TO OTHER SIMILAR PURPOSES." A communi-
cation from abroad by the Empire Vacuum Brake Company, of New York, in the
United States of America.
The said Invention relates more particularly to the pistons and cylinders of air
brakes and to ejectors to be used for exhausting the air from such cylinders, which
ejectors are also applicable to other similar purposes.
The brake apparatus consists of a vacuum cylinder containing two pistons, the
rods of which extend out through the heads of the said chamber in opposite directions
and connect with the brake levers of a railway carriage in combination with a pipe
which enters the vacuum cylinder at a point between the two pistons, and which
connects with an ejector or steam nozzle secured to or connected with the locomotive
boiler in such a manner that by admitting steam to the said ejector the air
from the vacuum cylinder is exhausted, and by the action of the atmosphere on
the two pistons in the said vacuum cylinder the brakes are simultaneously
applied to all the wheels of the carriage. Each of the pistons in the vacuum
cylinder may consist of a single head or they may be constructed with two heads
and an intermediate air space communicating through a channel in the piston rod
with the exhaust space of the cylinder. The packings of the heads are composed
of rings of leather or other flexible material, which project beyond the outer surfaces
of the heads when double heads are employed. By the combined action of the two
heads the intermediate air space and the projecting packing rings leakage of air
past the piston is prevented, and at the same time comparatively little power is
required to move the piston in the vacuum cylinder.
The vacuum cylinder is constructed of blocks or pieces of wood of suitable shape
and thickness placed one over the other so that the grain or structure of each piece
shall be at right angles to the grain or structure of the preceding piece. These
pieces are held in place by any suitable adhesive substance, and firmly bolted-
together by bolts running through the structure and secured by a nut at each end.
By means of these arrangements the tendency of the material to expand or contract
is counteracted, and the form of the cylinder in which the piston heads travel is
preserved without substantial change under the various conditions of dryness and
moisture, and of heat and cold.
The ejector consists of a steam nozzle provided with a conical spout, which fits
into the mouth piece of the nozzle, leaving between its outer surface and the inner
surface of the said mouth piece an annular space communicating with the steam
supply pipe in such a manner that steam admitted through the said supply pipe
rushes out through the annular space between the spout and mouth piece and by
the current of steam thus created the air in the spout and in the air exhaust pipe
is rarefied.
The conical spout is secured in position by means of a screw, thread, or other
equivalent means, so that it can be moved in or out, and that the annular space
between the said spout and the mouth piece can be regulated, the mouth piece
being fitted to a flange on the body of the nozzle so that access can be had to the

page_text: conical spout, and the annular space between, the spout and the mouth piece can be
adjusted without disturbing the connecting pipe.
The steam pipe and the air pipe are arranged so as to produce a more direct and
powerful action of the steam at the outlet of the air pipe than has heretofore been
attained. The air pipe at its outlet is completely surrounded by the steam pipe
which projects beyond the mouth of the air pipe, and when the steam is introduced
the column of air at the outlet of the air pipe will be completely surrounded by a
sheet of steam. The air pipe leads by a gentle curve from its union with the steam
pipe to the vacuum chamber in the cylinder or other vessel, and the steam pipe by
a like curve leads to the boiler, this improvement thus avoids an angle both in the
steam pipe and the air pipe and the loss of power consequent thereon.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the several Figures on the annexed Sheet of Drawing, the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 of the accompanying Drawings represents a sectional elevation of a
portion of a railway train with the Invention applied thereto.
Figure 2 is a corresponding plan.
Figure 3 represents a horizontal section drawn to a larger scale than the previous
Figures of the vacuum cylinder and pistons detached.
Figure 4 is a similar view to Figure 3, illustrating a modification in the construc-
tion of the pistons.
•
Figure 5 represents a vertical section drawn to an enlarged scale of the ejector
detached.
A, designates the platform of a railway carriage which is supported by two trucks
or bogies B, B, each having four wheels C, C, as shewn in Figure 2. Between the
two trucks is situate the vacuum chamber D, (shewn in detail in Figure 3,) which
is fastened to the underside of the platform A. This vacuum chamber is made in
the form of a cylinder, and is provided at about the middle of its length with an
opening a, which connects by a branch pipe b, (Figure 2) with a pipe E extending
throughout the entire length of the train, and connected with an ejector or steam
nozzle F, (shewn in detail in Figure 5) secured to the boiler of the locomotive. In
practice the pipe E will be made in sections, each section being equal in length to
the carriage or tender to which it is to be attached, and the several sections are
secured to each other by flexible connections so that the pipe E can accommodate
itself to the sinuosities of the train. The ejector F is constructed as herein-after
described, so that by admitting steam thereto the air in the pipe E and in the
vacuum chambers connected to the said pipe will be rarefied. The vacuum chamber
D is provided with two pistons G, G, which are situate at opposite sides of the
aperture a. The rods c of the pistons extend through the heads m of the vacuum
chamber, and they connect by chains & with levers e, which have their fulcra on the
brake heads f, extending across the inner wheels of the truck B. From the said
levers extend rods g to the brake heads f', which extend across the outside wheels
of the truck B, the brake heads being suspended from the truck frames by means of
pins or rods which pass through the brake shoes g', g¹.
According to one arrangement each piston G consists of a single head, composed
by preference of wood, and having a packing ring of leather or other suitable
material, which projects beyond the outer surface of its head, as shewn clearly in
Figure 3, or the modification, shewn in the detail Figure 4, may be adopted, in which
the pistons G are each constructed with two heads, h, h¹ with an intervening ai
space i, which communicates by a channel j in the piston rod with the exhaus
space between the two pistons. Each of the heads and is furnished with a
packing ring or cup or which is made of leather or other suitable material, and
projects beyond the outer surface of its corresponding head. If the air is exhausted
from the vacuum chamber D the packing ring is exposed to a uniform pressur
from all sides, while the packing ring is exposed to atmospheric pressure from th

page_text: outside through the inlets m, and to the pressure of the rarefied air from the inside,
and consequently the said packing ring is firmly held in contact with the sides of
the vacuum chamber and no leakage can take place. At the same time the inner
head forms a guide for the piston, and the said piston can be moved in the
vacuum chamber with comparatively little power. When the brakes are to be
applied steam is admitted to the ejector F, the air in the vacuum chamber D
becomes rarefied, the pistons G are forced inwards by the atmospheric pressure, the
leverse swing toward each other, and the brake shoes g¹, g, are drawn up to all
the wheels of the trucks B, B, at the same time, and may be held in contact with
the wheels for any desired length of time and with an undiminishing power, so
that a train of cars can be stopped from the engineer's stand within a comparatively
short space.
When the connection between the ejector and the boiler is closed
the brakes are taken off by the force of their own springs, the power of which is so
regulated that they also carry back the pistons G to their original position.
Having thus described the apparatus generally, I shall now proceed to explain
more fully the peculiar construction of the vacuum chamber and of the ejector.
The body of the vacuum cylinder is constructed of blocks or pieces of wood 1,
, of suitable shape and thickness placed one over the other so that the grain or
structure of each piece 7 shall be at right angles to the grain or structure of the
neighbouring pieces . The pieces 1, 1, are held in place by any suitable adhesive
substance, and firmly secured between the cylinder heads m by bolts n running
through the structure and secured by a nut at each end. In power brakes
operated by the pressure of the atmosphere against the partial vacuum power is
necessarily limited to the pressure of a single atmosphere, it is therefore important
that the piston heads should move with as little friction as possible, yet be packed
so as to be air-tight while the vacuum is being produced and maintained,
the amount of friction necessary to this result depends greatly upon the material
of which the cylinder and piston head are constructed, as well as upon the pack-
ing of the piston head. By the use of a wooden cylinder and a wooden piston
head with leather packing, constructed in the manner herein-before described, the
friction is much less than in a cylinder of iron or other metal, and the peculiar
manner of packing the piston head, herein-before described, avoids friction, except
at the moment when the pressure of the atmosphere against the partial vacuum
commences, when the vacuum is destroyed the friction is also relieved and the
piston head is moved back to its proper position by the use of a trifling amount
of power.
In constructing the cylinder pieces of suitable wood well. seasoned, of say about
an inch in thickness, are cut from planks with the grain running lengthwise, as
such planks are usually sawed the surfaces of these pieces are made as level and
smooth as practicable, a sufficient number of the pieces are then glued together with
their grain running in opposite directions, and when the whole mass is thoroughly
dried the interior is bored out of suitable size for the reception of the piston head.
The interior is carefully polished, care being taken to preserve uniformity in
the diameter for the entire length. After the piston heads, have been fitted
with their packing, and the cylinder has been completed by bolting it from end
to end and closing the ends, and before the cylinder is applied to the carriage,
the piston heads are worked backwards and forwards in the cylinder by any suit-
able power for several hours, and until the piston heads and their packing have
worked away or adjusted themselves to any small inequalities in the interior of the
cylinder. When this operation is properly performed, and the cylinder is applied
to a carriage, as soon as the extraction of the air begins to produce the partial
vacuum, the atmospheric pressure on the outer side of the piston head expands or
swells out the leather packing so as to make it air-tight, and it is obvious that as
soon as the vacuum is destroyed the packing falls back and allows the piston head
to, move back with little friction. The piece of leather for the packing is cut in
such a curved form that when applied around the piston head, and its ends are

page_text: brought to a proper joint, its periphery has a somewhat larger diameter than the
diameter of the piston head. It is obvious that the piston head being as nearly as
possible exactly the diameter of the bore of the piston head when thus packed and
in operation the packing will constantly press against the inside of the bore and
this pressure will increase with the production of the vacuum.
The peculiar construction of the ejector is illustrated by the detail, Figure 5, of
the Drawings; o is a steam pipe communicating with the steam boiler, and
2' is a
branch (by preference cast in one with the pipe o) connected with the space from
which the air is to be exhausted. The air exhaust pipe leads by a gentle curve
from its union with the steam pipe o to the vacuum chamber, and the steam pipe o
by a like curve leads to the boiler.
This arrangement admits of the angle in the steam pipe and air pipe being
obviated, thereby preventing the loss of power which attends the use of ejectors of
the ordinary construction. The steam pipe o at its outlet completely surrounds
the air pipe p from which rises a conical spout q extending up into the mouth
piece of the ejector. This mouth picce is also tapering and the steam admitted
through the pipe o rushes out through the annular space s between the spout q
and the mouth piece, and as it passes out of this annular space it carries with it
a portion of the air contained in the spout q, and thereby the air in the air pipe p
is rarefied, a check valve t which is situate in the air pipe 2 prevents the steam
from passing into the said air pipe, and when the air in the pipe is rarefied by
the current of steam this valve opens and the air in the air pipe is allowed to rush
out. The spout is secured to the pipe p by means of a screw thread or any
other equivalent contrivance so that it can be adjusted up or down, and that the
annular space s can be increased or diminished according to the pressure of steam
injected through the pipe o. On the upper end of the steam pipe o is formied a
flange u for the reception of the bottom flange of the mouth piece, which is secured
in position by screws v. By this arrangement access to the spout q may be readily
obtained whenever required, and the spout q be adjusted with facility.
Having now described and particularly ascertained the nature of the said Inven-
tion, and the manner in which the same is or may be used or carried into effect,
I would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part recited
Letters Patent is--
First. Constructing the vacuum chamber of blocks or pieces of wood arranged
so that the grain or structure of each block or piece shall be at an angle to the
grain or structure of the neighbouring blocks or pieces, substantially as and for the
purpose herein-before described.
Secondly. The combination (in an ejector of an air exhaust pipe and a steam pipe
diverging by a gentle curve from their point of juncture to their respective connec-
tions) of a removeable conical mouth piece, and of an adjustable conical spout, all
substantially as and for the purpose herein-before described.
Thirdly. The combination with the vacuum cylinder D constructed of blocks or
pieces of wood 1,, the longitudinal air pipe E and the ejector F of the pistons
G, G, piston rods c, c, and brake mechanism, substantially as herein-before described
and illustrated by the accompanying Drawings.
In witness whereof, I, the said John Henry Johnson, have to this my Speci-
fication set my hand and seal, this Eleventh day of October One thousand
eight hundred and seventy-six.
°
J. HENRY JOHNSON. (L.S.)