Improvements in Air Compression Pumps for Railway Air Brakes, and in the Mechanism for Operating same.
Year: 1896

page_text: Date of Application, 31st Mar., 1896-Accepted, 2nd May, 1896
COMPLETE SPECIFICATION.
Improvements in Air Compression Pumps for Railway Air Brakes,
and in the Mechanism for Operating same.
I, GEORGE SANFORD LEE of Hawthorne, in the County of Passaic in the State
of New Jersey, United States of America, Civil Engineer, 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 has relation to air brakes which are especially designed and adapted
for use on cable and electric railways, and has for its object the provision of certain
improvements in the air compressor or pump and in the mechanism by which the
pump piston is operated from one of the axles of the car.
My present invention consists in the novel construction and combination of parts
hereinafter described and claimed, having special reference to the compressor and
its operating mechanism.
In the accompanying drawings: -
Figure 1 is an end view partly in section of the compressor pump.
Figure 2 is a plan view partly in section of the same.
Figure 3 is a central horizontal sectional view of part of the piston.
Figure 4 is a vertical central sectional view of the pump without the cylinder
heads.
Figure 5 is a side view of the pump.
Figure 6 is an underside plan view of the pump, pump operating mechanism and
automatic governor mounted on a motor car.
The air compressor or pump comprises a pump cylinder or casing, a reciprocating
piston and a rotary piston shaft on which is mounted an eccentric and an eccentric
yake, to impart from the rotary shaft to the piston the required reciprocating
motion, the piston shaft being rotated from one of the axles of the car through the
medium of the gearing and connected mechanism hereinafter described.
The casing or cylinder of the compressor consists of two substantially similar
flanged and interiorly turned casings, I, 1, secured together by bolts 1, i, through
flanges 1, and having half boxes 1, 15, at right angles to the axis of the cylinder,
to form bearings for the piston shaft 1, which turns in suitable brasses 1', fitted in
the boxes I, 1, and extends out through one of the boxes to connect with the
driving mechanism.
The pump or compressor casing is connected by an air supply pipe with the air
reservoir from which another pipe, C10, leads to an automatic governor, which is
mounted in a casing surrounding the pump driving mechanism.
The compressor piston consists of two cylindrical discs or heads I, 110, having
projecting from their inner faces the bored bosses,, through which pass the
bolts,, connecting the two heads together and leaving a space between their
inner faces for the play of the eccentric and eccentric yoke by which the piston is
reciprocated. The bosses, are formed with matching rebates or offset
shoulders 7.
The inner faces of the heads 19, 110, are channelled or grooved at 10, to afford
guidance to the eccentric yoke 1, the latter being a rectangular collar made in
two half sections bolted together and bored out centrally to afford a bearing for
the eccentric I", which is keyed or turned solidly upon the piston shaft. A plate of
steel is fitted in each groove 10, to afford a slide bearing for the yoke and to take
up all wear, being cheaply replaced when desired. As the piston shaft rotates, the
eccentric imparts to the yoke a "four motion" action, which alternately thrusts

page_text: the piston positively in opposite directions. The cylinder and piston of the pump
are so constructed that the stroke of the piston will be very short, but the latter is
of much greater area than usual, its diameter being greater than the length of the
pump cylinder. At each stroke, therefore, a large supply of free air is taken in,
and in this way the pump has an extra large compressing capacity under a slow
motion of the piston.
This is obviously a great advantage, as the strain, wear and tear are reduced to
a minimum and heating of journals avoided.
The pump is made with as few parts as possible for the purpose of obtaining
strength and durability, aud is made short so as to economize space under the car.
The cylinder heads are provided with suitable suction and discharge valves,
which need not be specifically described.
The piston of the compression pump is operated from one of the axles of the car
which is designated A, in the drawings; and I shall now describe the mechanism
through which the piston is so operated.
PUMP OPERATING MECHANISM.
To the axle A, of a car, a toothed pinion N, is keyed, and such pinion engages
with a large toothed wheel N', mounted loosely on a shaft N, having its bearings
in a suspension frame N, etc., which is mounted on the axle on either side of the
pinion N. Upon a shaft N, is mounted a slide clutch member O, which is held
in rotative connection with the wheel N" loosely mounted on the shaft N. When
the clutch member O, is in pressure contact with the wheel N1, the latter
communicates motion to the shaft N13, through the clutch, and the shaft in turn
communicates motion to the rotary shaft of the pump piston through the universal
shaft connection P, P, etc.
Now, it will be understood that while the car is running and the gearing is in
active operative connection with the pump piston, the latter is continually
compressing air and storing the same under increasing pressure in the reservoir.
When, however, the desired maximum pressure is attained, the automatic
governer operates, admitting the air under full pressure to the automatic governor
which then actuates the lever N, and through the latter disengages the clutch
member O, from the wheel N", and allows the gears N, N1, N to rotate indepen-
dently of their connections with the pump piston, which latter becomes inactive.
The lever N, is connected to suitable manually operative mechanism so that, in
the event of a failure by the automatic governor to work, and upon the observance
by the motorman of an abnormal increase in pressure, the clutch member O, may
be mechanically withdrawn and in this way the operation of the pump arrested.
The manner and means of supporting the suspension frame and its connections
at their forward end will depend in a large measure upon the structure of the car.
The pump driving mechanism is enclosed within a suitable casing N', which is
supported at one end upon the axle of the car by suitable bearings, while the other
end suspended from the floor of the car or supported upon the channel bearings, in
such a manner as to yield and adapt itself to the forward and backward play of the
axle carrying the motor.
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
First. In air brake systems, a compressor pump, consisting of a casing having a
cylindrical bore of uniform diameter throughout its length, a piston consisting of
two discs of the same diameter as the interior of the cylinder, with their opposing
faces formed with ways for the play and guidance of a yoke, a piston shaft having
an eccentric mounted thereon, and an eccentric yoke embracing said eccentric and
arranged to move in said ways so as to impart from the rotary motion of the piston
rod a reciprocating motion to the piston, substantially as described.

page_text: Secondly. In air brake systems, the combination with a pinion mounted on a car
axle, of a compressor pump having a rotary piston shaft passing through its
cylinder, a gear wheel loosely mounted on said piston shaft and meshing with said
pinion, a sliding clutch member mounted on the gear wheel, and an automatic
governor operated by air pressure and coupled to the sliding clutch member,
substantially as described.
Thirdly. In air brake systems, the combination with a compressor pump and
gearings for driving the same from the car axle, of a shaft connecting the pump
piston and gearing and made in sections connected together by a flexible or a
universal coupling, substantially as described.
Fourthly. A compressor pump for air brakes, consisting of a cylinder having a
bore of uniform diameter throughout its length, with air inlet and outlet valves,
a hollow cylinder piston composed of two cylindrical recessed heads, bolted together
and formed with diametrical ways on their inner faces, a shaft passing laterally
through said cylinder and piston, and having an eccentric mounted or formed thereon,
and a rectangular sliding yoke embracing said eccentric and sliding in said ways,
substantially as described.
Dated this 30th day of March 1896.
GEORGE SANFORD LEE,
By Henry Skerrett,
24 Temple Row, Birmingham, Agent for Applicant.