Improvements in Pressure Reducing Valves for Air Motors
Year: 1899

page_text: Date of Application, 23rd May, 1899-Accepted, 29th July, 1899
COMPLETE SPECIFICATION.
Improvements in Pressure Reducing Valves for Air Motors,
2
I, JAMES CRAIG, Jr., of the Borough of Manhattan, City of New York, State
of New York, United States of America, 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:-
This invention refers particularly to air motors for propelling street railway
cars, and relates to the reduction or delivery valve by which the air is admitted
to the motor from the storage reservoir on the car.
As is well known in all such motors, the air in the reservoir is at a greater
pressure
than is required to operate the motor, and consequently
as
the air passes through the valve into the motor the pressure
is reduced, by the valve itself, to the required degree. Hereto-
fore in the operation of these motors, the air delivered by this reduction valve
has always been at a fixed uniform degree of pressure, but it frequently happens
in the case of railroad traffic that a greater pressure, or more power is required
in the motor at certain times and on certain portions of the road than the normal
pressure delivered by the valve, as for instance, when the car is to be propelled
up a steep incline or around a sharp curve; and the object of this invention is to
produce a reduction valve in which the pressure of the air in the motor can be
increased by the driver or motor-man on the car whenever necessary.
This invention consists in certain novel features of construction of the reduction
valve whereby the pressure of the air delivered by the valve can be readily and
quickly increased when desired, and afterwards returned to the normal pressure;
and whereby the reduction valve is caused to act as a throttle-valve for the
motor.
In the accompanying drawing illustrating my invention Fig. 1 is a side
elevation of the valve, partly in section; Fig. 2 is an end elevation of the same;
Fig. 3 is a similar view to Fig. 1 showing the position of the parts when the
delivery pressure of the valve is increased and Fig. 4 a modified construction
of the valve.
1, 1 is the double valve, and 2, 2, the valve seats; 3 is the valve piston extend-
ing upward through the casing; and 4 is the flexible diaphragm connected to and
moving with the piston. On the upper side of this diaphragm, and arranged to
press down on the latter, is the spiral spring 5, which is set at any degree of
pressure by the screw-sleeve 6, screwing into the valve casing at 7. 8 is the inlet
port communicating with the reservoir, and 9 the outlet port communicating
with the motor. 10 is a passage way between the outlet port and the chamber 11,
beneath the diaphragm 4.
In the operation of the valve, as soon as the air in the outlet port 9 and
chamber 11 is at a degree of compression less than the initial tension at which
the spring 5 is set, the spring forces down the diaphragm 4, and the latter in
moving carries with it the piston 3 and thus opens the valve 1, 1. The air in

page_text: the inlet port 8, which is always at a greater degree of compression than the
pressure or tension of the spring, then rushes through the valves into the outlet
port 9, and through the passage 10 into the chamber 11, and pushes up the
diaphragm, against the pressure of the spring, and closes the valves. The valves
remain closed until the small quantity of air in the outlet port and chamber 11
expands and decreases in pressure below the tension of the spring, when the
latter again acts on the diaphragm and opens the valves, and lets in some more
air at the higher degree of compression. As will thus be seen the air in the
outlet port communicating with the motor is always maintained at a constant
pressure slightly less than the initial pressure of the spring, as the moment it
falls below this latter pressure the spring opens the valve and introduces more
air at the higher pressure of the reservoir into the outlet port. The force of the
air in the inlet port 8 is so great that when the valve is opened but a very short
distance, the air rushes through the valve and the passage 10, and acting on the
diaphragm instantly closes the valve. A very small quantity of air at this high
degree of compression thus passes through the valve at any one time, and this
readily expands and decreases in pressure in the outlet port to the required
degree. The valves are thus constantly opening and closing, and an intermittent
stream of air at the high degree of pressure of the reservoir in thus passing from
the inlet port, through the valves into the outlet port where it has an oppor-
tunity to expand and decrease in pressure to the required degree as it passes into
the motor. The air in the outlet port is thus reduced by the action of the valve
from the higher degree of compression of the reservoir to the lower degree deter-
mined by the initial pressure of the spring. As this pressure of the spring may
be increased or diminished by the screw cap 6, the spring may be set to open the
valve at any pressure desired, and thus reduce the pressure of the air passing
through the valve to any required degree.
As will thus be seen, the operation of the reduction valve is automatic, and the
valve is caused to move the instant the air is permitted to pass from the air
reservoir and continues to operate until the passage of the air from the reservoir
is stopped.
To control therefore the passage of the air from the reservoir, it has been
necessary heretofore to employ with the reducing valve a throttle valve, which
when opened will allow the air to pass from the reservoir through the reduction
valve into the motor, and which when closed will shut off the passage of the air
and stop the operation of the motor.
With this invention I am enabled to do away with the separate throttle valve,
and by mechanism connected with the reducing valve to shut the latter and
hold it closed so that the air cannot pass from the reservoir until the valve is
allowed to open; and thus cause the reducing valve to also act as the throttle
valve.
This mechanism connected with the reducing valve is as follows:-
Mounted on the valve casing by the bolts 12 is a toggle-joint consisting of
the members 13 and 14, and the operating lever 15, connected together by the
bolts 16, so as to turn on each other. The members 14 of the toggle-joint are
connected to the cross-head 17, through which the valve piston passes, and in
which it freely slides. As will be understood from the drawing, when the toggle
lever 15 is pulled over to one side, the cross-head 17 is drawn down along the
piston towards the spring 5. Near the top of piston and directly above the cross-
head 17, when at its highest point, is a nut 18, screwed onto the piston, as shown
in Fig. 1. When the toggle-joint is in the position shown in Figs. 1 and 2,
that is with the lever 15 raised, and the joint 13 and 14 in line, the cross-head 17
is jammed up tight against the nut 18 on the piston. The piston is now securely
held in its upper position and prevented from moving downward and opening
the valves 1. 1. The valve is thus closed and the air shut off from passing into
the motor. By moving the lever 15 down a short distance the toggle-joints acting
on the cross-head 17 draw the latter down away from the nut 18, thus liberating

page_text: the movement of the piston, and allowing the spring, acting on the diaphragm,
to push down the piston and open the valves.
By means of this toggle-joint therefore I am enabled to operate this reduction
valve as a throttle-valve, and to instantly close the valve and hold it shut against
the action of the spring for any length of time, and as quickly to free the move-
ment of the valve and allow it to be operated, as above described. The nature
of the toggle joint is such that a very slight movement of the lever operated by
suitable mechanism from either end of the car, is all that is necessary to com-
pletely shut off the passage of the air from the motor, or allow the valve to open
and permit the air to pass at once into the motor.
In the construction and operation of my improvement, as thus set forth, the
valve controlled by the toggle-joint acts as a throttle-valve and as a reduction
valve, allowing the air to come from the reservoir and at one uniform degree of
pressure to pass into motor.
While the pressure of the spring, and hence the delivery pressure of the
valve may be adjusted by the screw sleeve 6, it is very desirable to have some
other means of quick adjustment of the valve immediately under the control of
the motorman, whereby he can increase the pressure of the air delivered by the
reducing valve, and thus increase the power in the motor whenever it is desired
during the run of the car and while the latter is in motion.
In the construction shown in Figs. 1, 2 and 3, loosely surrounding the piston,
between the cross-head 17 and the spring 5, is an inner sleeve 19. The lower
portion of this sleeve is enclosed by the adjusting sleeve 6, within which it freely
slides. The upper part of the sleeve 19 in the construction shown in the drawing,
screws into the adjusting sleeve 20, by means of which the position of the sleeve
with respect to the cross-head 17, and consequently the extent of its movement,
is regulated. The bottom of the sleeve 19, rests on the top of the spring 5, as
shown in Fig. 1; and, as the tension of this spring is regulated by the adjusting
sleeve 6, the sleeve 19 moves up or down so as to always be in contact with the
upper end of the spring.
In the ordinary operation of the valve when the air delivered at the uniform
pressure determined by the initial tension of the spring is all that is required
in the motor, the sleeve 19 remains in the position shown in Fig. 1, resting
on the top of the spring. When, however, greater power is required in the
motor, and hence a greater pressure of the air delivered by the valve, the lever 15
is turned down as shown in Fig. 3. The toggle-joints now draw the cross-head
down on the adjusting sleeve 20, or on the top of the sleeve 19, and slide the
latter sleeve down on the spring 5, compressing the spring and thus increasing
its tension, and thereby increasing the pressure of the air delivered by the valve
and passing through the outlet ports into the motor.
As will be understood, if the initial tension of the spring was a little over
200 pounds so that the pressure of the air delivered by the valve was 200 pounds,
and the additional tension of the spring caused by its compression by the sleeve 19
is a little over 250 pounds, the valve would act when the air in the outlet ports
had decreased to 250 pounds instead of 200 pounds.
As long as the parts are held in position shown in Fig. 3, with the sleeve 19
compressing the spring, the increased pressure of air is delivered into the motor;
but as soon as the occasion for this extra power in the notor is past, and the
usual pressure of air determined by the normal initial tension of the spring is
all that is required, the lever 15 is raised, relieving the pressure of the cross-
head 17 on the top of the sleeve 19, and allowing the spring to expand upward,
and carry the sleeve 19 with it, until it bears against the adjusting sleeve 6.
The parts are then in their normal position, as seen in Fig. 1, and the operation
of the valve is controlled by the spring at its initial tension, and the pressure of
the air reduced to the degree required for the usual working of the motor.
In Fig. 4 is shown a modified construction of the valve regulating mechanism,
which is as follows:

page_text: This
Connected to the valve stem above the diaphragm 4 is a second flexible
diaphragm 21 operated as in the case of the first diaphragm by the pressure of
the air on its under surface, and by the force of the spring above it.
diaphragm 21 has a less effective area, or exposes a less surface to the pressure
of the air than the diaphragm 4.
The enclosed chamber 22 between the diaphragms communicates by means of
a channel or conduit 23 and a suitable valve 24, either with the outside air or
with the tube 25 leading from the delivery port 9.
In the construction shown in Fig. 4, the valve 24 is a three-way cock, which
is operated by any suitable mechanism from the end of the car by the motor-
but any form of cock or valve may be used that is found desirable.
man,
In the ordinary operation of this form of the reducing valve, when the air as
delivered by the valve at the normal pressure is sufficient to operate the motor,
the three-way cock 24 is turned so that the conduit 23 communicates with the
outer air, and the chamber 22 is filled with atmospheric air. There is now no
pressure but the pressure of the atmospheric air on the upper diaphragm 21,
and this diaphragm therefore performs no function in the operation of the
valve; the diaphragm merely moving up and down with the valve stem.
When, however, a greater pressure or more power is required in the motor
the cock 24 is turned as shown, so that the conduit 23 connects with the tube 25,
and the chamber 22 is in communication with the delivery port 9 of the valve,
and is thus filled with air at a pressure.
As will be understood, as both the chambers 11 and 22 are now in communica-
tion with the delivery port, they both contain air at the same degree of pressure,
and hence it follows that there is the same pressure on both sides of the dia-
phragm 4, and this diaphragm is thus balanced between the two equal pressures,
and has no further effect in operating the valve.
The effective diaphragm is now the upper diaphragm 21, which is operated by
the pressure of the air in the chamber 22, and by the force of the spring 5. As
the diaphragm 21, as before stated, is of less effective area than the diaphragm 4,
it will require a greater pressure acting on this diaphragm to balance the force
of the spring than was required on the other diaphragm; and hence it follows
that the spring at the same tension will overcome a greater pressure acting on
the diaphragm 21, and will thus force this diaphragm down and open the valve
when the air in the delivery port is at a greater degree of pressure than it would
when acting with the diaphragm 4.
For instance if we suppose the spring to be set when operating with the
diaphragm 4 to open the valve when the air in the delivery port is at 150 pounds
pressure then the spring at the same tension when operating with the dia-
phragm 21 of less effective area, will open the valve when the air in the delivery
port is at a greater pressure than 150 pounds, or, we will say, at 200 pounds, and
thus cause the reducing valve to deliver air at a greater pressure into the motor.
Hence, with this improvement by merely turning the cock or valve 24 so
that the chamber 22 between the two diaphragms communicates with the delivery
port of the reducing valve the pressure of the air delivered by the valve is
increased above the normal pressure and more power is obtained in the motor.
As soon as the necessity for the increase of power in the motor is at an end,
it is only necessary to turn the cock back so that the chamber 22 communicates
with the outer atmosphere when the original operation of the valve with the
diaphragm 4 is resumed and air at the normal pressure passes through the
valve.
As will be understood the area of the diaphragm 21 may be regulated so that
any desired increase in the pressure of the air may be obtained.
The driver of the car, or motorman, is thus enabled to apply more power to
the motor whenever necessary, and to maintain this increase of power as long
as required.

page_text: my said
Having now particularly described and ascertained the nature of
invention and in what manner the same is to be performed I declare that what
I claim is:
1. In a reducing valve apparatus for air motors, the combination of the reducing
valve, valve stem operating the same, toggle-mechanism controlled by the
operator, and a member connected with the valve-stem and arranged to engage
with the toggle-mechanism whereby the reducing valve is closed and held on its
seat, substantially as described.
2. In a reducing valve apparatus for air motors, the combination of the reducing
valve, valve-stem operating the valve, nut 18 connected with the valve-stem, and
a toggle-mechanism controlled by the operator and arranged to engage with the
nut on the valve-stem, whereby the reducing valve is closed and held from
opening, and the passage of air from the reservoir is shut off, substantially as
described.
3. In a reducing valve for air motors a flexible diaphragm operated by a spring
and mechanism for adjusting the spring to its normal pressure; the combination
with the valve of additional mechanism, controllable by the operator, adapted to
further compress the spring and increase its tension above its normal adjustment,
whereby the delivered fluid-pressure of the reducing valve is increased, sub-
stantially as described.
4. In a reducing valve for air motors, having a flexible diaphragm operated
by a spring, in combination, the spring; mechanism for adjusting the spring to
its normal tension; and additional mechanism, controlled by the operator, for
further compressing the spring above its normal tension, whereby the delivered
Huid-pressure of the reducing valve is increased, substantially as described.
5. In a reducing valve for air motors having a flexible diaphragm operated by
a spring, in combination, the spring; means for adjusting the spring to its normal
tension; other means whereby the spring may be further compressed and its
tension increased above its normal adjustment; and toggle-mechanism adapted to
operate the latter, by which the delivered fluid-pressure of the reducing valve is
increased, substantially as described.
6. In a reducing valve for air motors the combination with the valve of
mechanism adapted and arranged when in one position to close the valve and
hold it from opening, and when in the other position to act on the valve and
increase the pressure at which the reducing valve opens, whereby the delivered
fluid-pressure of the valve is increased, substantially as described.
7. In a reducing valve for air motors, in combination, the valve; a spring
adapted to regulate the tension of the valve; and toggle-mechanism connected with
the valve, and arranged when in one position to close the valve and hold it from
opening, and in the other position to act on the spring and increase the tension of
the latter and the pressure at which the reduction valve opens, substantially as
described.
8. In a reducing valve, in combination, a flexible diaphragm connected to
and arranged to operate the valve; a second flexible diaphragm of less effective
area, also connected to and arranged to operate the valve; and mechanism whereby
either diaphragm is caused to operate the valve to vary the delivery pressure,
substantially as described.
9. In a reducing valve for air motors having a flexible diaphragm operated
by a spring; the combination with the valve of a second diaphragm of less effec-
tive area; and mechanism whereby the second diaphragm is caused to operate the
valve in place of the first and deliver air at an increased pressure, substantially
as described.
10. In a reducing valve for air motors, in combination, the diaphragm 4
arranged to operate the valve; diaphragm 21 of less effective area also arranged
to operate the valve; chamber 22 between the diaphragms and mechanism whereby
the chamber is caused to communicate with the delivery port of the valve and

page_text: with the outside air and throw the separate diaphragms into and out of operation
and thereby vary the delivery pressure of the valve, substantially as described.
11. In a reducing valve for air motors, in combination, a diaphragm 4, arranged
to operate the valve; a diaphragm 21 of less effective area, also arranged to operate
the valve spring 5 adapted to act upon both diaphragms to open the valve;
chamber 22 between the diaphragms and means by which the chamber is caused
to communicate with the outside air, whereby the valve is operated by dia-
phragm 4, or with the delivery port, whereby the valve is operated by
diaphragm 21 and the delivery pressure of the valve increased, substantially as
described.
DL
11011
1900
JAMES CRAIG, JR.
Haseltine, Lake and Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
JAMES CRAIG, JR.
Haseltine, Lake and Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.