Note: Descriptions are shown in the official language in which they were submitted.
CA 02455138 2004-02-11
AUTOMATIC APPLICATION HAND BRAKE
FIELD OF THE INVENTION
The present invention relates, in general, to hand brake assemblies for use on
railway type vehicles and, more particularly, this invention relates to an
apparatus to
automatically activate and apply the brakes on such railway vehicle without
requiring
an operator to manually wind the chain on such hand brake.
This application is a division of copending commonly owned Canadian
Patent Application No. 2,331,433 filed January 18, 2001.
BACKGROUND OF THE INVENTION
Prior to the conception and development of the present invention, railway car
hand brake mechanisms were well known in the art. They usually include a
large,
rotatable hand wheel disposed in a vertical plane and mounted on a shaft
which,
through a gear train, can rotate a chain drum to wind up a chain that is
secured at its
end remote from the chain drum to the brake rigging of the railway car. As the
hand
wheel is rotated in one direction, the brakes are applied and rotation of the
hand
wheel shaft in the opposite direction is prevented by a pawl which engages a
detent
wheel on the hand wheel shaft.
The brakes may be released by disengaging the pawl from the detent wheel but
this causes rapid rotation of the hand wheel and the gears of the gear train.
To avoid
rapid rotation of the hand wheel, hand brake mechanisms have been devised
which
are known as "quick release" mechanisms. Generally these quick release
mechanisms
include a releasable connecting means between the hand wheel shaft and the
gear
train. When the connecting means is released, the gears of the gear train
rotate
rapidly, without constraint by the pawl and detent wheel, but the hand wheel
remains
stationary.
The Association of American Railroads (AAR) promulgates specifications for the
design and operation of railway car hand brake mechanisms. Vertical wheel,
gear
train, hand brake mechanisms are classified in three categories, namely:
(1) Standard power - provides an average force on the chain of 3350 Ibs.
with a 125 Ib. turning force applied to the rim of a wheel twenty-two inches
in
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diameter.
(2) Intermediate power - provides an average force on the chain of 4475 Ibs.
with a 1z5 Ib. turning force applied to the rim of a wheel twenty-two inches
in
diameter.
(3) High power - provides an average force on the chain of 6800 Ibs. with a
125 Ib. turning force applied to the rim of a wheel twenty-two inches in
diameter.
After setting of the brakes, when the hand brake mechanism is released the
gears of the gear train rotate rapidly. This results in the gears and other
components
being subjected to high forces and to shock, particularly, when the chain
becomes fully
let-out from the chain drum.
In recent times, the AAR has added a life cycle test to its specifications,
and
hand brake mechanisms which do not meet the life cycle test cannot be sold for
use
on railway cars operated in interchange service on United States railroads.
The AAR
life cycle test for quick release brakes requires that such latter brakes
withstand 3000
quick release operations.
To meet such life cycle test requirements, even standard power hand brake
mechanisms had to be modified when the life cycle test was adopted. When
intermediate power hand brake mechanisms of the type sold prior to the
adoption of
the life cycle test were subjected to the life cycle test, it was found that
the
components thereof wore prematurely or were damaged, and it was found to be
necessary to add a shock retarder, or absorber, external to the hand brake
mechanism, to overcome such wear and damage. Of course, such an external shock
retarder is undesirable not only because it is external to the hand brake
mechanism
but also because of the additional cost and because it requires field
modification of the
equipment on a railway car if the intermediate power hand brake mechanism is
used
to replace a standard power hand brake mechanism.
High power hand brake mechanisms sold prior to the adoption of the life cycle
test were similarly unable to pass the life cycle test. It should be borne in
mind that
such high power brake mechanisms normally have additional gears to provide the
desired force on the chain, and this results in a higher speed of rotation of
at least
some of the gears during release of the hand brake mechanism.
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Although the use of an external shock retarder might have solved the problems
with the higher power hand brake mechanism, a change in the AAR specifications
would have been required to permit the use of such an external shock retarder.
Attempts were made to redesign the high power hand brake mechanism, such as by
making it stronger, so that it would meet the life cycle test without the use
of an
external shock retarder, but the attempts were not successful.
One of the characteristics of railway car brakes with which the invention is
concerned is that the force applied to the chain, and hence, the parts of the
hand
brake, is non-linear and depends on the extent to which the brakes are applied
or
released. Thus, as the brakes are applied, relatively little force is required
to take up
the slack in the chain and the brake rigging, but to meet AAR requirements,
the final
force on the chain must be as set forth hereinbefore, namely, 3350 Ibs. for a
standard
power brake, 4475 Ibs. for an intermediate power brake and 6800 Ibs. for a
high
power brake. After slack in the rigging is taken up, which may require, for
example,
5-15 inches of chain travel, the force on the chain increases exponentially,
e.g. from
200 Ibs. to the final value, as the brake hand wheel is further turned to set
the brakes.
In reaching the final value after the slack is taken up, the chain may travel
only two
or three inches. Similarly, when the hand brake is released, the chain force
decreases
exponentially and reaches a relatively small value shortly after the hand
brake is
released.
As can be seen from the above-discussion, it would be advantageous to have an
automatic application apparatus for applying the hand brake and thereby reduce
the
force required to apply the brakes.
According to a first aspect, the invention of the parent application is
predicated
upon the use of an apparatus that is engageable with a hand brake assembly
which
will automatically apply at least one brake means secured to a railway vehicle
with
such hand brake assembly. The apparatus comprises an operating means having at
least a portion thereof engageable with at least one gear of a gear assembly
disposed
in a housing member of the hand brake assembly for operating such gear
assembly in
a direction prompting an application of such brake means. A source of fluid
pressure
is connected to the operating means for periodically supplying a predetermined
pressure to such operating means which is at least sufficient to cause such
application
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of the brake means. A means is connected to the source of fluid pressure for
initiating
the supply of such predetermined pressure to the operating means thereby
causing an
automatic application of such brake means by the hand brake assembly. A timing
means is connected intermediate the operating means and the source of fluid
pressure
for controlling the predetermined pressure being periodically supplied to the
operating
means.
According to a second aspect, the invention of the parent application provides
an apparatus engageable with a hand brake assembly for automatically applying
at
least one brake means secured to a railway vehicle with the hand brake
assembly. An
operating means is provided which has at least a portion thereof engageable
with at
least one gear of a gear assembly disposed in a housing member of such hand
brake
assembly for operating such gear assembly in a direction which will cause an
application of the at least one brake means. A source of fluid pressure is
connected to
such operating means for periodically supplying a predetermined pressure to
the
operating means that is at least sufficient to cause such application of the
at least one
brake means. A means, connected to such source of fluid pressure, is provided
to
initiate the supply of such predetermined pressure to the operating means
thereby
causing an automatic application of such at least one brake means by the hand
brake
assembly. A timing means is connected intermediate such operating means and
such
source of fluid pressure for controlling the predetermined pressure being
periodically
supplied to the operating means. An overload protection means is connected to
one of
such source of fluid pressure and such operating means for preventing an
overload on
the at least one brake means.
SUMMARY OF THE INVENTION
The present invention provides an apparatus engageable with a hand brake
assembly for automatically applying at least one brake means secured to a
railway
vehicle with such hand brake assembly. Such apparatus consisting of a motor
means
having a rotatable shaft which carries a gear member thereon. The gear member
is
engageable with at least one gear of a gear assembly disposed in a housing
member
of such hand brake assembly for operating the gear assembly in a direction
which will
cause an application of such brake means. The apparatus further includes a
means
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CA 02455138 2004-02-11
connected to such motor for starting the motor and thereby initiating an
automatic
application of such brake means by the hand brake assembly.
In addition to the foregoing features and advantages of the present invention
generally described above, various other features and advantages of the
invention will
become much more readily apparent to those persons who are skilled in the
relevant
art from the following more detailed description, particularly, when such
detailed
description is taken in conjunction with the attached drawing figures and the
claims
appended hereto.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front elevation view of a hand brake assembly incorporating a
portion of a presently preferred embodiment of the automatic application hand
brake
of the invention;
Figure 2 is a side elevation view of the hand brake assembly illustrated in
Figure
1;
Figure 3 is a front elevation view of the hand brake assembly illustrated in
Figures 1 and 2 with the front cover removed;
Figure 4 is a top view of the hand brake assembly illustrated in Figures 1-3;
Figure 5 is a perspective view of the hand brake assembly illustrated in
Figures
1-4;
Figure 6 is a schematic illustration of a presently preferred operating
mechanism including an activation means for use with the hand brake assembly
illustrated in Figures 1-5;
Figure 7 is a schematic illustration of an alternative embodiment of an
operating
mechanism including an activation means for use with the hand brake assembly
illustrated in Figures 1-5;
Figure 8 is a schematic illustration of another alternative embodiment of an
operating mechanism including an activation means for use with the hand brake
assembly illustrated in Figures 1-5;
Figure 9 is a side elevation view partially in cross section of a presently
preferred embodiment of a cylinder portion of the operating mechanism operably
connected to a rack assembly engageable with a gear portion of such operating
CA 02455138 2004-02-11
mechanism for use with the hand brake assembly illustrated in Figures 1-5;
Figure 10 is a front elevation view of a hand brake assembly which
incorporates
another alternative embodiment of the automatic application hand brake of the
invention;
Figure ii is a top view of the hand brake assembly illustrated in Figure 10;
and
Figure 12 is an exploded view of the slip clutch mechanism of the various
embodiments of the invention.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED AND
VARIOUS ALTERNATIVE EMBODIMENTS OF THE INVENTION
Prior to proceeding to the more detailed description of the various
embodiments
of the present invention, for the sake of clarity and understanding of such
invention, it
should be noted that identical components having identical functions have been
identified with identical reference numerals throughout each of the figures
illustrated
herein.
Refer now, more particularly, to Figures i through 6 of the drawings.
Illustrated therein is an apparatus, generally designated i0, which is
engageable with
a hand brake assembly, generally designated 20, for automatically applying at
least
one brake means (not shown) secured to a railway vehicle (not shown) with such
hand
brake assembly 20.
Such apparatus 10 includes an operating means, generally designated 30.
Operating means 30 has at least a portion thereof, i.e., gear 12, engageable
with at
least one gear 14 of a hand brake gear assembly, generally designated 40,
disposed in
a housing member 16 of such hand brake assembly 20 for operating such gear
assembly 40 in a direction which will cause an application of such at least
one brake
means.
The apparatus 10 further includes a source of fluid pressure, generally
designated 50, connected to the operating means 30 for periodically supplying
a
predetermined pressure to such operating means 30 that is at least sufficient
to cause
such application of such at least one brake means. The presently preferred
fluid
pressure is pneumatic.
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CA 02455138 2004-02-11
The final essential element of the apparatus 10 is a means, generally
designated 60, which is connected to the source of fluid pressure, preferably
a
reservoir 18, for initiating the supply of such predetermined pressure to the
operating
means 30, thereby causing an automatic application of such at least one brake
means
by such hand brake assembly 20.
According to one presently preferred embodiment of the invention, such
apparatus 10 will further include a timing means, generally designated 70.
Such
timing means 70 is connected intermediate such operating means 30 and the
source
of fluid pressure 50 for controlling such predetermined pressure being
periodically
supplied to the operating means 30. Timing means 70 preferably includes a
choke 21
and a reservoir 22.
In such presently preferred embodiment, apparatus IO further includes an
overload protection means, generally designated 80. Such overload protection
means
80 has a first portion 24 thereof that is connected to such source of fluid
pressure 50
and a second portion 26 thereof that is connected to the operating means 30
for
preventing an overload on such at least one brake means.
As shown in Figure 7, such operating means 30 includes at least one valve
means 28 for connecting the source of fluid pressure 50 to such operating
means 30.
However, as can be clearly seen in Figures 6 and 8, the operating means 30 may
include a plurality of such valve means for connecting the source of fluid
pressure 50
to such operating means 30. The valve means for these embodiments will be
explained in further detail hereinafter.
In each of the presently preferred embodiments of the invention, the first
portion 24 of the overload protection means 80 that is connected to such
source of
fluid pressure 50 acts as a means for venting fluid pressure from the
plurality of valve
means and such at least one valve means 28.
Additionally, in these embodiments such operating means 30 includes a piston
member 32 connected to the source of fluid pressure 50. Such piston member 32
responding in a first direction in response to such fluid pressure and in an
opposed
second direction by means of a spring 34.
Preferably, the apparatus 10 further includes a valve shifting means,
generally
designated 90. A first portion 36 of the valve shifting means 90 is connected
to such
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CA 02455138 2004-02-11
piston member 32 and a second portion 38 of such valve shifting means 90 is
connected to valve 52 of such plurality of valve means.
The presently preferred means 60 for initiating the supply of such
predetermined pressure to the operating means 30 is one of a push button 44
and a
signal communicated to the means 60 for initiating such supply of
predetermined
pressure. The signal that is communicated to the means 60 for initiating such
supply
of predetermined pressure will be received, for example, by a solenoid valve
46. The
most preferred means 60 for initiating the supply of predetermined pressure to
the
operating means 30 is push button 44.
It should be recognized that when the means 60. for initiating the supply of
predetermined pressure to the operating means 30 is a signal communicated to
such
operating means 30 it may be either a radio frequency signal or, preferably,
an
electrical signal.
In the embodiment of the invention illustrated in Figure 7, the overload
protection means 80 will preferably include a pressure regulating means 48.
The
apparatus 10 may further include a slip clutch, generally designated 130,
connected to
such operating means 30 to provide such overload protection means 80 for the
operating means 30.
According to the most preferred embodiment of the present invention such
apparatus 10, which is engageable with hand brake assembly 20, includes an
operating means 30. At least one gear i2 of operating means 30 is engageable
with
at least one gear 14 of a gear assembly 40 which is disposed in a housing
member 16
of such hand brake assembly 20 for operating such gear assembly 40 in a
direction
which will prompt an application of such at least one brake means (not shown).
The apparatus 10 also includes a source of fluid pressure 50 connected to the
operating means 30 for periodically supplying a predetermined pressure to such
operating means 30 that is at least sufficient to cause the application of the
brake
means. The presently preferred fluid pressure is pneumatic.
Another element of the apparatus 10 is a means 60 which is connected to the
source of fluid pressure for initiating the supply of such predetermined
pressure to the
operating means 30, thereby causing an automatic application of such at least
one
brake means by the hand brake assembly 20.
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Such apparatus 10 will further include a timing means 70 which is connected
intermediate such operating means 30 and the source of fluid pressure 50 for
controlling such predetermined pressure being periodically supplied to the
operating
means 30. Such timing means includes choke 21 and reservoir 22.
The final element of the apparatus 10, in the most preferred embodiment, will
include an overload protection means 80. Such overload protection means 80,
preferably, has a first portion 24 thereof that is connected to such source of
fluid
pressure 50 and a second portion 26 thereof that is connected to the operating
means
30 for preventing an overload on such brake means.
Refer now, more particularly, to Figures 10 and 11. Illustrated therein is an
apparatus, generally designated 100, engageable with a hand brake assembly 20
for
an automatic application of at least one brake means secured to a railway
vehicle with
such hand brake assembly 20. The apparatus 100 includes a motor means,
generally
designated 110, having a rotatable shaft 102 which carries a gear member 104
thereon. Such gear member 104 is engageable with at least one gear 14 of a
gear
assembly 40 disposed in a housing member 16 of the hand brake assembly 20 for
operating such gear assembly 40 in a direction which causes an application of
the
brake means. The apparatus 100 also includes a means, generally designated
120,
connected to such motor 110 for starting the motor and thereby initiating an
automatic application of such brake means by the hand brake assembly 20. Such
means 120 for starting the motor 110 may be, for example, electrical wires
106.
As can be seen from the above discussion, the apparatus 10, of the present
invention, provides a device that will enable an automatic application of a
hand brake
even in the event of a loss of an electrical signal. In this case, the hand
brake can be
push button applied rather than use of electronic braking. Electronic braking
provides
the advantage that all the brakes can be applied from the locomotive with
proper
controls. On the other hand, if the electronic system is malfunctioning, the
push
button can still initiate the hand brake. This would be a case where it is
possible to
have a parallel system, i.e., push button and electronic. In the instant
invention push
button and electronic braking can be utilized in parallel with each other
without a
problem. Additionally, with the electronic system it is possible to select
certain hand
brakes to be applied as a function of programming. If it is desired, one hand
brake
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CA 02455138 2004-02-11
could be set on every ten cars down the train, for example. In essence, the
present
invention provides a system which can be designed as three distinct schemes.
One
pneumatic, one electronic and a combination of both pneumatic and electronic.
In the embodiments of the invention described above, it is expected that the
capacity of the reservoir 18 should generally be in the range of between about
400
cubic inches and about 1,400 cubic inches. Preferably, such reservoir 18 will
have a
capacity of between about 400 cubic inches and about 700 cubic inches. It may
be
possible to use a smaller reservoir 18 because it is relatively easy to work
valve 52
initially and the cam system 54 is going to increase the system efficiency,
therefore, it
will not require as much air in such reservoir 18. In other words, 700 cubic
inches
may be the worst case scenario based on the assumption that a 90 psi system is
being
used and the total amount of energy that applied assumes every stroke of the
cylinder
went to full pressure in each stroke. Obviously, when one starts winding the
chain
(not shown) one will not need full pressure on the cylinder because it's going
to be
easy to wind up. Therefore, the cam 54 is going to cause it to reciprocate and
return
without reaching full pressure so it should not require a significant amount
of air
pressure.
For example, assume we've got a charged reservoir 18 and everything is
settling into a steady state where the cylinder piston 32 is completely
returned by its
spring 34. Consequently, there is no air pressure behind the piston 32, and to
start an
application all that is required is to push the push button 44 attached to
valve member
56 which begins the whole process. It allows air into reservoir 58. Reservoir
58 may
or may not be a physical reservoir in the circuit. It could be, for example, a
volume of
the pipe. In any case, it allows air to pass from reservoir i8 into reservoir
58 which
then operates (2) pilot operator valves 62 and 64. This moves valve 62 into
the
connected position and valve 64 is moved to a vented position. There is a
direct
connection 66 from the 700 cubic inch reservoir 18 which passes through the
valve 64
to the timing reservoir 22. In this manner, the timing reservoir 22 is charged
prior to
starting. There are two power operated valves 68 and 72 which are shifted.
Valve 72
is in the closed position to start with and valve 68 is in the connected
position.
Just for explanation purposes only, pressure limits will be provided where
these
valves are going to drop out based on spring loads in the valves and based on
the
CA 02455138 2004-02-11
pressure of the timing reservoir 22.
As is evident, the system is designed to cause the piston 32 to reciprocate
when
the push button 44 is pushed in order to wind up the brake. After some amount
of
time, the piston 32 is required to completely return. Because it has to
completely
disengage, the rack 74 attached to piston 32 has to completely disengage from
the
gear 37 in order to perform all the manual functions of the hand brake
accurately.
The final operation requires the piston 32 to return all the way back to its
initial
position in order to clear the rack 74 from gear 37. This is accomplished
through the
timing means 70. For example, say there is an 18 inch chain, there will be so
many
strokes of the piston 32 required within a certain period of time. When that
time is
reached, say around 45 seconds to a minute, the piston 32 is going to stroke.
The
piston 32 will reciprocate about 26 times to do a full application on a
standard 9300
type hand brake. However if it's a 4493 type hand brake, or 40 inch take up,
it will
take several additional strokes, or a longer cylinder, or a longer rack and it
will require
more air.
With the reservoirs 18 and 22 charged and with the piston 32 in the starting
position and utilizing a system having 90 psi and a 700 cubic inch reservoir
22, when
the push button 44 is pushed, connection to valve member 56 is established.
This
charges reservoir 58 which, in turn, shifts valves 62 and 64. Valve 64
connects timing
reservoir 22 to a vented choke 21.
With push button 44 activated, valve 56 connects the 700 cubic inch reservoir
18 to reservoir 58 which causes valves 62 and 64 to shift. Now valve 64 starts
reducing the pressure. The valve member 62 connects the 700 cubic inch
reservoir 18
through to valve member 52. Valve member 52 is hooked to the reciprocating cam
54. When the piston 32 is in the home position it will be connected as shown
in Figure
6, which means it's passing through the valve 68. Since there is pressure in
the
timing reservoir 22, the valve 68 will, also, be shifted to the right hand
side and
connected behind the piston 32. Now there is a complete path with the
reservoir 18
through valve 62 and through valve 52 and through valve 68 to the back side of
the
piston 32. With air flowing through the back side of the piston 32, the piston
32 is
now driving the rack 74 down into the main drive gear 37 and causing the hand
brake
20 to wind up. Once the piston 32 reaches the bottom of its stroke it's going
to pick up
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a pin on cam 54 and the valve shifting mechanism is going to cause valve 52 to
reciprocate. This will cause the valve member 52 to shift to a different
position. Valve
member 52 will then vent the air in the cylinder and the spring 34 is going to
push the
air back out of the cylinder or to atmosphere. When it gets almost to the top
of its
stroke, the cam 54 is going to pick-up again and shift valve 52 in the other
direction,
which is going to cause air to go back in the cylinder again. The apparatus 10
will
continue this cycle until it gets the hand brake 20 completely wound up. It
will require
different amounts of air pressure in the cylinder to apply the brake at
different stages
of chain wind up. At the beginning of the application process it is going to
be
relatively easy, the pressure needed to extend the piston 32 will be rather
low. The
piston 32 is going to extend until it hits the cam and then the piston 32 is
going to
retract. The following strokes will require more and more pressure because the
chain
will become tighter and tighter. On the last stroke, the design of the system
is to be
no less than 40 psi starting from 90 psi, the initial condition, in a 700
cubic inch
reservoir. This will ensure that with the size of our cylinder the 40 psi will
give enough
input force into the rack in combination with the gear advantage. In the
drawings,
there is a pair of gears shown connected. Such gear advantage is achieved by a
large
main drive gear and a little drive gear that will provide a 42 to 1 mechanical
advantage in order to get the chain moving. So long as there is 40 psi, a full
load will
be exerted on the chain.
It may be desirable to add an indicator (not shown) to show how tight the
brake
is set. This may be a sensor which could be used as a feedback. A sensor on
the
apparatus 10 could be used as a feedback to the electronic system (not shown),
so
that the locomotive controls can tell when the brake is anywhere between 3/4
on to
full on, or completely released. Preferably, a spring is provided on these
valves and
the pilot operated valves 68 and 72, that will cause the cylinder to go
completely
home, regardless of where it is set based on the spring loadings and the
valves.
Valves 68, 72, 64 and 62 are connected together and will be sequenced by a
spring
load to get the cylinder to go home. This initially happens when the spring on
valve
68 is the strongest, so as the timing reservoir dies, valve 68 is going to
flip over to a
vented position first. Assume that the pressure in reservoir 18 goes from
about 90 psi
to 20 psi. At 20 psi valve 68 vents the air out of the cylinder, which
retracts the
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piston 32 all the way home. The next highest load on the spring is going to be
in
valve 72, which may drop to about 18 psi, causing valve 72 to shift over. The
spring
is going to overcome the air pressure exerted on the pilot side and valve 72
is going to
vent the circuit that drives valve 64 and valve 62.
As reservoir 58 is venting through valve 72 the next highest spring toad is
going
to be valve 62. This load may be at about 16 psi in reservoir 58, as venting
is
occurring, it goes through 16 psi and the valve 62 will close off the
reservoir 18 from
the rest of the circuit. From valve 52 and valve 68, valve 64 is going to be
the lowest
spring and, therefore, it will shift back to a connected mode to start
charging the
timing reservoir 22. This basically completes the operation from an initial
charge.
Another thing that must be considered is the case where the pneumatic
circuitry
is completely empty and it must start from scratch. Here the emergency
reservoir 76,
shown in Figure b, is completely empty and the circuit from the hand brake is
completely empty and the system must start from a complete zero and go through
the
circuit. On the other hand, it may be possible to start from a medium charge,
because
after an application of the hand brake 20 there is still typically 40 psi left
in that
cylinder. Assuming an air tight system, the next time the system is charged it
may
only require charging the 700 cubic inch reservoir 18 from 40 psi to 90 psi or
something in the middle. Once everything charges up to 90 psi the system is
equalized and ready for operation.
While the presently preferred embodiment and various additional alternative
embodiments for carrying out the instant invention have been set forth in
detail in
accordance with the Patent Act, those persons skilled in the hand brake art to
which
this invention pertains will recognize various alternative ways of practicing
the
invention without departing from the spirit and scope of the appended claims.
Accordingly, to promote the progress of science and useful arts, we secure for
ourselves by Letters Patents for a limited time exclusive rights to all
subject matter
embraced by the following claims.
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