AUTOMATIC CAR-BRAKES AND VALVES THEREFOB
Year: 1887

page_text: Date of Application, 21st Mar., 1887.
Specification Accepted, 22nd Apr., 1887.
I, ALBERT PARSONS MASSEY, of Watertown, in the County of Jefferson and
State of New York, United States of America, Engineer, do hereby declare the
nature of my invention for AUTOMATIC CAR-BRAKES AND VALVES THEREFOB, and in
what manner the saine is to be performed, to be particularly described and ascertained
in and by the following statement :-
My invention relates more especially to the valves that regulate the distribution of
fluid pressure between a reservoir and a diaphragm or cylinder for actuating brakes.
I am aware that various devices have been made for operating the valves between a
reservoir and a brake cylinder or diaphragm automatically, and that some have
attempted to hold the valve midway of its stroke by springs or by varying the area of
the diaphragm. My device is not like these, but makes use of two diaphragms or
pistons opposed to one another and united by means of an intermediate lever or bell-
crank in such a manner that as the position varies from one extreme of the stroke to
the other the effective leverage of one diaphragm or piston to move the valve is
constantly decreasing, while the effective leverage of the other is constantly
increasing. In this way, by varying the pressure in the train-pipe more or less, the
valve can be moved to any part of its stroke and held there.
Figure 1 is a diagram or plan view showing the relative positions of the several
parts.
Figure 2 is a vertical longitudinal section of the valve chamber.
Figure 3 is a detail.
A is a shell enclosing the valve mechanism, and connected with the reservoir B by
pipe b.
A vacuum is maintained in the reservoir B and the shell A by means of an ejector
or pump, which may be located on the locomotive, and is connected with a pipe C
running under and secured to the car, the several pipes being united by suitable
couplings between the cars to form a continuous train-pipe.
In a branch C of the train-pipe communicating with the reservoir B is a check-
valve c, which allows the air to pass from the reservoir to the pipe, but checks any
flow into the reservoir.

page_text: D is a flexible diaphragm of rubber, leather, or the like, exposed on its inner side to
the vacuum in the shell and on its outer side to the vacuum in the train-pipe C, which is
connected by a branch with the chamber E, from which a small passage e runs to
the closed chamber E' behind the diaphragm D. The chamber E also communicates
with the interior of shell A by means of opening e', in which is seated an outwardly
opening check-valve e².
The diaphragm D) is connected by means of a stem F with one arm of a bell-crank
lever G pivoted at H, and provided with two noses G, G². The other arm of
lever G is connected by means of double stem with a diaphragm I, which is
exposed on its inner side to the vacuum in shell A, and on its outer side to the
atinospheric pressure through opening a
Resting upon the nose of lever G is the stem of the valvo J which controls an
opening between the interior of shell A and a chamber K; said chamber K communi-
cating by means of pipe L with the diaphragmn-shell M, and by means of opening k,
chamber N, and hole n with the outside air.
In the chamber N is a diaphragm O carrying a valve 01, above which is a spring O².
Above the diaphragm O is a smaller chamber N¹ which is connected by passage l'
with the interior of shell A through passage P1, and with the outside air through "
A valve R, the stem of which is engaged by the nose G2 on lever G, controls the
passages P and P
In figure 2 the parts are shown in their normal positions. The valve J is free from
the nose of lever G, and rests upon its seat. The valve R is held up by the nose G²
so as to close the opening P2, while the passage P is open; the vacuum in chamber A
will therefore exist also in chamber N', and the release valve O' will be held open by
the atmospheric pressure on the underside of diaphragm 0. This atmospheric
pressure will therefore exist in chamber N, opening &, chamber K, pipe L, and
diaphragm-shell M, and the brakes will be uninfluenced by the diaphragm in shell M.
The diaphragm D is in equilibrium, since the vacuum is the same in the reservoir
and the train-pipe.
thus
The operation is as follows; If the vacuum in the train-pipe C be partially destroyed
the increase of pressure on the outside of the diaphragm will press it in and open
the valve J, at the same time dropping the valve R and closing the opening P1, and
opening P2 so that the air can pass through P2 and P to the chamber N
equalizing the pressure on the two sides of diaphragm O, and allowing the spring to
close the release-valve O'. The vacuum in shell A is communicated through valve J,
chamber K, and pipe L, to the diaphragm-shell M, resulting in a movement of the
diaphragm in said shell, which applies the brakes.
If the apparatus consisted simply of the diaphragm D and the valve J, arranged as
described, the diaphragm would move its whole stroke whenever the pressure varied
enough to make it move at all, and the brakes would be applied with full force or
would all be off. To enable the valve to be moved slowly and held in any desired
position, the diaphragm 1 is added. This diaphragm is exposed to the fluid-pressure of
the reservoir on one side, and to the atmosphere on the other. It is connected with
the main diaphragm D by means of stem F, lever G, and stem F, the stems being
connected with the lever at such an angle that the diaphragm I offers a constantly-
increasing resistance to the movement of the diaphragm D and the valve J. The
leverage of the diaphragm D to revolve the lever Ĝ about its pivot H is constantly
decreasing as the valve opens, while the leverage of the diapliragm I to resist such
motion about pivot H is constantly increasing. This enables the engineer to control
the location of the valve at will by regulating the pressure in the train-pipe C.
It is obvious that by connecting the diaphragins to different points of the bell-
crank G any varying resistance may be obtained that may be desired.
When the vacuum is restored in the train-pipe C and shell A, the diaphragm D
will return to its normal position, dropping the valve J and raising the valve R, thus
admitting the vacuum to chamber N again, and lifting the release-valve O', which
admits air to the pipe L and the diaphragin-shell M and releases the brakes.

page_text: Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is :-
1. In a fluid-pressure brake, a release-valve actuated directly by the fluid-pressure
through an auxiliary valve which opens communication alternately between the
diaphragm or piston which actuates said release-valve and the auxiliary reservoir, and
between said diaphragm or piston and the atmosphere, substantially as shown and
described.
2. In a fluid-pressure brake, the combination of bell-crank G, valve R, and
diaphragm O with suitable air ports or passages to actuate diaphragm O by fluid-
pressure, substantially as shown and described.
3. The combination of diaphragms D and I with the bell-crank G and the detached
valve J, substantially as shown and described.
4. The combination with reservoir B, train-pipe C, and diaphragm-shell M, of.
shell A enclosing a valve-mechanism consisting of diaphragms D and I, bell-crank G,
detached valves and R, release-valve O¹, and suitable passages whereby said
mechanism may be operated by fluid-pressure, substantially as shown and described.
Dated this 21st day of March 1887.
HERBERT J. ALLISON,
Agent for the Applicant.