U.S. patent number 3,650,216 [Application Number 04/849,083] was granted by the patent office on 1972-03-21 for railway car speed control transportation system.
This patent grant is currently assigned to Rex Chainbelt Inc.. Invention is credited to Joseph Wesley Broome, Warren J. Harwick.
United States Patent |
3,650,216 |
Harwick , et al. |
March 21, 1972 |
RAILWAY CAR SPEED CONTROL TRANSPORTATION SYSTEM
Abstract
Individual cars of an operator-less railway transportation
system are driven along a pathway by cooperation of a motor driven
drive tube in each car that cooperates with angularly positioned
reaction wheels spaced along the pathway. Controls are included for
varying, in response to external signals, the angular position of
selected reaction wheel assemblies to bring a car smoothly to a
stop at a predetermined point, to bring a car past a particular
point at a predetermined speed at a predetermined time, to insert a
car from a side path into a gap in traffic on a main path, or to
selectively delay cars to create gaps in the traffic to accept cars
from a branch path.
Inventors: |
Harwick; Warren J. (Milwaukee,
WI), Broome; Joseph Wesley (Milwaukee, WI) |
Assignee: |
Rex Chainbelt Inc. (Milwaukee,
WI)
|
Family
ID: |
25305021 |
Appl.
No.: |
04/849,083 |
Filed: |
August 11, 1969 |
Current U.S.
Class: |
104/166; 104/167;
104/168; 104/295; 105/30; 246/182R; 104/288; 105/26.05; 198/349;
104/88.06 |
Current CPC
Class: |
B61B
13/125 (20130101) |
Current International
Class: |
B61B
13/12 (20060101); B61b 013/12 (); B61c 011/00 ();
B61c 013/00 () |
Field of
Search: |
;104/147,149,152,165,166,167,168,88,130,147R ;105/26,29,26R,30
;246/18Z,18R ;198/110 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: La Point; Arthur L.
Assistant Examiner: Beltran; Howard
Claims
We claim:
1. A speed control for regulating the movement of individual cars
of a transportation system in which each car is propelled by
contact between a rotating drive tube on the car and a reaction
wheel positioned along the path of the car, comprising signal means
that are energized if the car speed is to be reduced at a
particular station, pivotal means supporting a reaction wheel
located at such station, motor means along the trackway operatively
connected to the pivotal means, and means responsive to the signal
for energizing the motor to pivot the reaction wheel to a slow
speed position.
2. In a speed control according to claim 1 car detecting means at a
station, and means connecting said car detecting means to the
reaction wheel pivoting means at an adjacent station behind the car
for pivoting said reaction wheel to its zero speed position.
3. In a speed control system according to claim 1, a series of
speed control means located along a portion of the path of the
cars, means for sequentially setting said control means to low
speed position to produce an expanding low speed zone and a
collapsing high speed zone, and means for simultaneously returning
all of said series of control means to high speed position, whereby
the spacing between the cars is reduced in said low speed zone and
the cars are accelerated to high speed without increase in
spacing.
4. In a speed control according to claim 1 means coupling the
pivoting means of a series of reaction wheels for pivotal movement
of the wheels to selected positions by operation of a single
reaction wheel pivoting means.
5. A speed control according to claim 4 in which said coupling
means pivots successive wheels of the series of reaction wheels
different amounts whereby a speed changing zone is established.
6. In a speed control according to claim 5 car detecting means at a
station and means connecting said car detecting means to the
reaction wheel pivoting means of the next station behind the car
for pivoting that wheel to zero speed position and successive
reaction wheels to reduced speed positions whereby the presence of
a car at a station establishes a deceleration zone extending from
said next station.
7. In a speed control according to claim 1 car position control
means for pivotally deflecting the reaction wheel controlling the
car in accordance with the position of the car relative to a fixed
point comprising catch means operatively connected to the reaction
wheel pivoting means and a member on the car cooperating with the
catch means.
8. A speed control according to claim 7 in which the catch is
operatively fixed with respect to the reaction wheel pivoting
means, and serves in cooperation with the member on the car to
position the reaction wheel precisely in its zero speed
position.
9. In a speed control according to claim 7 means for moving the
catch with respect to the reaction wheel pivoting means along the
path of the car.
10. In a speed control system according to claim 1, car detecting
means on one path of a car leading to a junction of paths, a timer
operatively connected to said car detecting means, a pivoted
reaction wheel on a second path leading to the junction, and
control means responsive to said timer operatively connected to
said pivoted reaction wheel for pivoting said wheel to its zero
speed position during the timing interval of said timer.
11. A speed control system according to claim 10 in which the
timing interval is measured from the last operation of the car
detecting means.
12. In a speed control system according to claim 10, a series of
pivoted reaction wheels along said second path, and means
interconnecting the wheels for pivoting a reaction wheel of the
series as the next downstream wheel is pivoted.
Description
SUMMARY OF THE INVENTION
To meet the demands of some transportation systems it is necessary
to use a large number of small cars or carriers rather than a few
large carriers or trucks. For example, in handling passenger
luggage in an airport it is desirable to be able to directly and
promptly transport each piece of luggage to its destination without
waiting for a larger load or using a carrier that must stop at each
of a number of stations along its route. Small individually driven
and directed cars offer the greatest flexibility in transporting
such luggage between selected stations of the systems.
One of the requirements in such a system is the accurate control of
the car speed over various portions of its travel and accurate,
shock free positioning of the car for various operations such as
loading, unloading, elevating or synchronizing the car movement
with that of other cars when moving from a branch track or pathway
onto a heavily traveled main line, track or pathway. To coordinate
the movements of a number of cars it is desirable that all of the
control including car speed be trackside.
These requirements are met in a drive tube and reaction wheel
propulsion system by controlling the angular position of each of
the reaction wheels which are spaced along the track and which
cooperate with a constant speed rotating drive tube, mounted on and
extending lengthwise along the under side of the car. Preferably
the drive tube is driven by an electric motor energized through a
brush contacting a third rail. In those portions of the system
where all of the cars travel at a fixed speed the reaction wheels
are journaled in fixed supports. On those portions where a car or a
number of cars must be started and stopped or the speed varied, as
at a loading or unloading station, or on an approach to a main line
where the car must await a break in the main line traffic flow, the
reaction wheels are journaled on pivoted supports that can be moved
to any position between a no drive position (reaction wheel axis
parallel to the drive tube axis) and a full speed drive
position.
This arrangement, while it depends on friction between the drive
tube and reaction wheel, acts like a positive infinitely variable
drive to accelerate the car if it tends to run slower or to
decelerate or brake the car if it tends to run faster than the
selected speed.
The previously proposed systems using a series of drive tubes
journaled in the trackway or overhead to cooperate with reaction
wheels journaled in the vehicles such as shown in U.S. Pat. Nos.
402,933 and 402,934 to W. L. Judson or in U.S. Pat. No. 3,164,104
to W. A. Hunt do not afford the simplicity and reliability of
control from trackside that is obtained by locating the drive tube
in the car and the reaction wheels in the trackway.
In the previous arrangements failure of a drive motor incapacitates
the corresponding section of track thus blocking all the cars.
Whereas in the new system failure of a car carried drive motor
incapacitates that particular car which may easily be removed from
the system without affecting any other car.
Only those parts of the new system actually in use are running. In
contrast, in the previous systems all of the drive tubes along a
track must be running regardless of the number of cars actually in
operation.
A luggage carrier system embodying the invention is illustrated in
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a perspective view of a car as viewed from the right
rear.
FIG. 2 is a perspective view of a car as viewed from the left
rear.
FIG. 3 is a plan view of the frame of the car as seen from the line
3--3 of FIG. 4 to show the drive system in the car.
FIG. 4 is a transverse elevation of the frame of the car and track
as seen from the line 4--4 of FIG. 3.
FIG. 4a is a fragmentary view showing an alternative alignment of a
reaction wheel with respect to the drive tube.
FIG. 5 is a sectional view of one end of the drive tube and its
support taken along the line 5--5 of FIG. 4.
FIG. 6 is a fragmentary view of an optional arrangement of a drive
tube cooperating with a pair of reaction wheels to provide guidance
for the car.
FIG. 7 is an elevation of one of the running wheels of the car
showing its pivotal mounting.
FIG. 8 is a vertical section of the running wheel and its mounting
taken along the line 8--8 of FIG. 7.
FIG. 9 is a diagrammatic view of car switch cam follower mechanism
carried in the car.
FIG. 10 is a plan view of a section of track including a switch and
cam that cooperates with the switching cam follower mechanism shown
in FIG. 9.
FIG. 10a is a side view of an elevating cam positioned along the
track resetting the cam follower on the car as seen from the line
10A--10A of FIG. 10.
FIG. 11 is a fragmentary plan view of a section of track and a
power driven reaction wheel.
FIG. 12 is a plan view of a section of track showing pivotally
mounted reaction wheels including means for positioning a car.
FIG. 13 is a plan view of a section of track including means for
controlling the advance of a car according to a prescribed speed
and timing.
FIG. 14 is a diagrammatic view of a merging switch illustrating one
use for the car speed and positioning control shown in FIG. 12.
FIG. 15 is a diagrammatic view of a section of track in which speed
control is used to collect the cars into groups.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As an example, the novel propulsion system is shown as used to
drive individual cars of a luggage transporting system such as may
be used in an airport. An individual car is shown in FIGS. 1 and 2.
As shown, the car comprises a body 1 that is uniquely shaped to
receive the ordinary types of luggage commonly encountered. In
order to accommodate duffel bags and golf club bags and similar
elongated cylindrical pieces of luggage the forward end of the car,
the right end as seen in FIG. 1, is formed with a pair of
upstanding hollow boxlike portions 2 and 3 closed at the top and
sides and cooperating to form therebetween a recess 4 adapted to
receive one end of a duffel bag or similar article. The other end
of the duffel bag is carried in a cradle or valley formed by
sloping top portions 5 and 6 of a boxlike section 7 extending
transversely across the rear of the car. Ordinary suitcases and
similar articles are carried in the middle of the car, such
articles resting on an inclined surface 8 extending downwardly from
the left side of the car at an angle of approximately 20.degree. to
25.degree.. A steeply inclined surface 9 extending downwardly from
the left-hand side of the car meets this surface 8 at substantially
a right angle to thus form a generally V-bottomed receptacle for
suitcases. The rear end wall of the boxlike portions 2 and 3 toward
the front of the car and the front vertical wall of the rear
boxlike section 7 form vertical fore and aft boundaries for the
suitcase receiving portion of the car.
In use, luggage may be loaded from either side of the car. If
loaded from the right-hand side the luggage is placed on the gently
sloping inclined surface 8 and allowed to slide down until it comes
to rest against the steep surface 9. Duffel bags and similar
articles are loaded by placing one end in the recess 4 and the
other end in the cradle formed by the inclined surfaces 5 and 6. If
luggage is to be loaded from the left side of the car, it is lifted
over the high side of the surface 9 so that the end of the suitcase
rests against the surface 9 and it is then lowered until it comes
to rest on the surface 8.
Luggage is automatically discharged from the car at appropriate
positions by tilting at least the body of the car to the right
about a longitudinal axis through an angle of approximately 65 to
70 degrees so that the luggage slides off the inclined surface 8
onto a receiving conveyor. Duffel bags and golf club bags are
oriented during the discharge operation since the rear end of such
bags slides off the surface 6 before the other end can pull free
from the recess 4. Thus such elongated articles are discharged
lengthwise onto the receiving surface.
Preferably the car is carried on flanged wheels 10 adapted to run
on rails 11.
The chassis of the car is shown in FIGS. 3 and 4. Referring to FIG.
3 the chassis itself includes a generally rectangular frame 12
which may be built of tubing or rolled sections. The wheels 10 are
individually mounted from the frame 12. To support the body 1 the
frame 12 has outriggers 13 provided with shear blocks 14 that are
connected to ribs 15 of the car body. The shear blocks 14 serve to
isolate the body of the car from the vibrations generated by
contact between the wheels 10 and rails 11.
The frame also carries a longitudinally extending rotatable drive
tube 16 that is resiliently supported from the frame 12 by
resilient mounting means 17 attached to the end sections of the
frame 12. As may be seen more clearly in FIG. 5 the drive tube 16
is tapered at each end, the end further being formed with a
reentrant portion 18 adapted to receive the outer races of a pair
of ball bearings 19. The inner races of the ball bearings 19 are
carried on a stub shaft 20 projecting horizontally from the lower
end of a cylindrical member 21 that extends upwardly in telescoping
relation with a tube 22. The tube 22 is mounted with shear blocks
23 to the end member of the frame 12. A compression spring 24
compressed between the closed upper end of the tube 22 and the
upper end of the cylindrical member 21 urges the member 21 and
consequently the drive tube 16 downwardly to a limit imposed by a
bolt 25 extending from the upper end of the tube 22 downwardly
through the cylindrical member 21. The drive tube 16 is driven
through a belt 26 from a drive motor 27 mounted in the frame 12 of
the car. While not shown in detail the belt 26 may be an ordinary V
belt or a toothed timing belt. The corresponding groove in the
drive tube 16 is of such a depth that the exterior of the belt is
substantially flush with or slightly recessed below the external
surface of the drive tube 16.
FIG. 4 shows the general arrangement of the parts of the chassis
and drive particularly as to their vertical relationship. It may be
noted that the tube mounting 17 for the drive tube 16 is inclined
from a vertical line so as to be generally normal to the line of
centers of the drive tube 16 and the motor 27. This inclination is
selected so that the belt can remain substantially constant as the
cylindrical member 21 slides up and down the tube 22 to accommodate
variations in height of various reaction wheels, such as the wheel
30, spaced along the track. Each of the wheels 30 is journaled in a
small stand 31 erected from a crosstie 32 carrying the rails
11.
While not shown in detail, each of the reaction wheels is
preferably a small rubber tired wheel carried on radial thrust
bearings from a stationary axle 33 mounted in the stand 31. The
allowable travel of the cylindrical member 21 in the sleeve 22 is
such that as the rotating drive tube 16 approaches one of the
reaction wheels 30 the tapered forward end engages and rotates the
reaction wheel as it climbs onto the wheel compressing the spring
24 in what ever amount is required.
The springs 24, one at each end of the drive tube, push the tube
down onto the reaction wheels with sufficient force so that the
frictional contact between the wheel and the drive tube provides
sufficient force to drive the car.
The speed at which a car passes one of the reaction wheels is
determined by the speed of rotation of the drive tube 16, which is
normally held fixed since it is driven by the constant speed motor
27, and the angle between the axis of the drive tube and the axis
of rotation of the reaction wheel, as measured in a horizontal
plane, i.e., the angle between the horizontal projections of the
two axes. This angle may vary from zero, the condition when the
axes are parallel, which provides for zero speed to an angle of
about 45.degree. to 50.degree. in which case the speed of the car
along the tracks is equal to or greater than the peripheral speed
of the drive tube 16.
In FIG. 4 the center of the reaction wheel 30 is shown as being
vertically beneath the center of the drive tube 16. In many
instances, particularly when the reaction wheels are oriented for
high speed travel, it is desirable to offset the reaction wheels
toward the descending side of the drive tube. This orientation is
shown in FIG. 4a, in which a counterclockwise rotating drive tube
16A cooperates with a reaction wheel 30A so positioned that a
vertical line through the reaction wheel passes between the
descending side of the drive tube and its axis of rotation. In this
orientation the line of force between the tube and wheel is
inclined so that the horizontal component of the force urging tube
against to the wheel offsets the tangential force between the tube
and wheel as the tube drives the wheel. Preferably the stand 31A is
set on a wedge or tipped so that a line normal to the axis of the
drive tube and the axis of rotation of the reaction wheel passes
through the center of the reaction wheel.
While it is preferable to use flanged wheels 10 riding rails 11
there may be occasions when it is desirable for the car to operate
on a flat surface without the guiding effect of the rails. In such
a case, a dual reaction wheel assembly may be used as illustrated
in FIG. 6. As shown, a second reaction wheel is provided to
cooperate with a first reaction wheel the two wheels being offset
from each other laterally of the direction of motion of the car as
shown by the position of wheels 30B in FIG. 6. The wheels thus form
a shallow V in which a drive tube 16B rests. By using stiff springs
in the reaction tube mounting, such as the springs 24 in FIG. 5, it
is possible to carry most of the weight of the car on the drive
tube and thereby secure enough lateral stability so that the car
follows the line of dual reaction wheels.
It may also be noted in the dual arrangement as well as the offset
arrangement of FIG. 4A, that if the car encounters any resistance
to its forward motion and the reaction wheels are oriented for a
forward drive there is a reaction force action on the drive tube
tending to move it to the left as shown in FIGS. 4, 4a and 6. This
reaction force is opposed by force between the flange of the wheel
10 and the rails 11 and the horizontal component of force produced
by the offset reaction wheel 30A or the left-hand reaction wheel
30B of FIG. 6.
This arrangement of the drive tube carried in the car and
cooperating with reaction wheels positioned along the trackway is
particularly advantageous for operatorless cars in that the speed
may be easily and accurately controlled by means in each section of
track and the same speed control is applied to each car passing
that section of track.
Also as seen in FIG. 3 each end of the car is provided with a
substantial rubber cushion or bumper 34 to absorb the shock as two
cars may come into contact with each other in normal operation
along the track.
Power for the motor 27, which preferably is a single phase electric
motor to reduce the number of energized third rails, is supplied
from a third rail assembly 40 supported from the ties 32 of the
trackway. The third rail assembly 40 preferably includes a first
section 41 that extends along a trackway to supply the power and a
second section 42 that is used just ahead of each of the switch
points. These third rails 41 and 42 are preferably of a more or
less standard construction in which a U-shaped conductor, in cross
section, is partially enclosed in a U-shaped plastic or nonmetallic
cover serving as a shield or insulator to protect the energized
conductor from accidental contact. A brush assembly 43 depending
from the frame 12 of the car has an insulating U-shaped portion
which fits generally over the outer insulating portion of the third
rail 41 and includes a tongue or brush that is forced into contact
with the energized third rail. Two of these brush assemblies 43 are
provided, one at each end of the car and located generally in line
with the wheels 10, to span the breaks or gaps in the third rail 41
required at track switches to provide clearance for the wheels 10
as they follow the switch track. Likewise locating the brushes
generally in the transverse line with the wheels 10 maintains a
relative constant spacing of the brushes and the third rail
regardless of whether the car is operating on a straight track or
on a sharp curve.
A second brush assembly 44 cooperating with a second third rail 42
provides electrical connection to a solenoid 45 mounted, by means
not shown, in the upper left-hand corner of the car as seen at the
right in FIG. 4.
In order that the car may negotiate sharp curves on the track it is
desirable that each of the wheels be mounted flexibly with respect
to the car frame 12 so that it may pivot about a vertical axis. A
suitable construction is shown in FIGS. 7 and 8. As shown, each of
the wheels 10 is provided with a hub section 50 fitted with ball
bearings 51, 52 the inner races of which are mounted on a spindle
53. The spindle 53 is welded or otherwise fastened to a king pin 54
the upper and lower ends of which are fitted with resilient
bushings 55 pressed or formed in brackets 56 and 57 bolted to a
mounting pad 58 as indicated in FIG. 3. A brush holder 59 is also
mounted on the king pin 54 to hold a brush assembly, the brush of
which rides on a polished surface 60 of the wheel hub 50 to provide
a return circuit for the motor 27 through the wheel 10 and the rail
11.
Since the wheels 10 must follow the track 11 and be able to
withstand considerable lateral force on the car, as when rapidly
negotiating a sharp curve, without pivoting in response to that
force, it is desirable that the axis of the king pin be precisely
vertical, i.e., normal to the track. This is in contrast to
ordinary construction in which the king pin in inclined slightly so
that the axis of the pin intersects the road surface ahead of the
center of pressure of the wheel whereby a caster effect is
obtained.
To minimize the possibility of disruption of service in the system
due to track switch malfunctions, a switching system using no
moving parts in the track is employed. In this arrangement, at each
switch, as shown in FIG. 10, the approach rails, as in common
railroad practice diverge, one rail following the straight line or
through track the other following the siding. The remaining rails
are arranged according to the usual practice except for the
omission of the moving portions of the ordinary switch. This track
arrangement is shown in FIG. 10.
A car approaching from the left is, if it is to pass straight
through, forced to its right by external means to be described, so
that the flanges of its right-hand wheels pass through the gap
between the bottom rail 11 and the corresponding switch rail 11A.
If the car is to follow the siding or branch line it is forced to
the left as it approaches and enters the switching area so that its
right-hand wheels follow the switch rail 11A. Plates 62 are
provided in the switching areas to support the flanges of the
wheels 10 as the wheels cross the gaps in the track.
The switching of the car at each switch point is controlled
automatically. When the car is loaded with luggage, address
information is encoded in a magnet plate 65 mounted in the lower
front left-hand side of the car as shown at the right in FIG. 4.
This magnetic address plate 65 incorporates a number of rods of
high retentivity magnetic material that is magnetized in a
particular pattern corresponding to the address to which the
luggage on the car is to be delivered. This magnetizing is
preferably done by a group of electromagnets mounted in the
trackway at the loading station as is indicated by the rectangle 66
marked "ENCODER" in FIG. 4. Just ahead of each switch point a
reader is mounted in the trackway in a position corresponding to
the encoder 66. The reader comprises a plurality of reed switches,
not shown, which through a decoding circuit closes a switch to
energize the third rail 42 and solenoid 45 if the car is to follow
the siding rather than the main track.
The cars, as shown, are normally conditioned to follow the
left-hand branch at each switch. In the event that a car is to
follow the right-hand branch the reed switches in the reading
circuit close the circuits to energize the solenoid 45. When it is
energized it operates a linkage shown in FIG. 9 (see also FIG. 4)
to raise a cam roller 67 on a left-hand side of the car to the
right as shown in FIG. 4 viewing the front end of the car) and
lower a cam roller 68 at the right front corner of the car. As
clearly shown in FIG. 9 the linkage from the solenoid 45 includes a
tension link 68 connected between a plunger 69 of the solenoid 45
and a guide rod 70 vertically slidable in a tubular guide 71 on the
frame 12 of the car. The cam follower roller 67 is mounted on the
lower end of the guide rod 70 in position to cooperate with a left
turn cam 72 mounted along the left-hand side of the trackway as
indicated in FIG. 10.
When the solenoid 45 is energized it not only raises the guide rod
70 but also acting through a linkage including a first arm 73,
pivot rod 74, second arm 75, drag link 76, third arm 77, pivot rod
78, and fourth arm 79 lowers a second guide rod 80 which carries
the cam roller 68 on its lower end. When the guide rod 80 is thus
lowered the cam roller 68 is in position to engage a right turn cam
81 which in FIG. 10, is the condition for the straight ahead travel
of the car. A spring detent 82 cooperates with the end of the arm
73 to hold the linkage at one end or the other of its travel. Thus
momentary energization of a solenoid is sufficient to switch the
mechanism to the position shown in FIG. 4 for a right turn or
travel to the right side of the switch.
After passing the switch the lowered cam roller 68 engages an
elevating cam 83 which forces the cam roller 68 upwardly and acting
through the linkage lowers the cam roller 67 and its guide rod 70
to their lower position past the detent 82, so the car switching
mechanism is returned to its normal position in which the car
follows the left-hand branch of a switch.
While cams 72 and 81 are shown to cooperate with the cam followers
67 and 68, the followers may be positioned to cooperate with the
adjacent rails, provided the followers can be located closely
adjacent the wheels and the curves in the track are not too sharp.
Otherwise it is difficult to locate the cam follower so that it
will work on both a curved rail and a straight rail.
The propulsion system in which the rotating drive tube is carried
in the car and cooperates with reaction wheels located along the
track allows additional power to be supplied directly to the
reaction wheels. Such power is needed for climbing steep grades and
at points where the car must be rapidly accelerated. One method of
applying additional power is illustrated in FIG. 11. As shown, a
section of track including rails 85 and 86 are mounted on a cross
tie 87 which supports a reaction wheel assembly 88 having a
reaction wheel 89 that is driven by an electric motor 90 supplied
with power through leads 91. Although a direct drive is
illustrated, a flexible shaft, universal joints or a belt drive may
be included in the drive so that the motor 90 may be located below
the plane of the rails 85,86 and the reaction wheel 89.
As was mentioned in connection with FIGS. 4 and 5, the speed and
direction of the car past a particular reaction wheel is determined
by the angle between the axis of rotation of the reaction wheel and
the rotating drive tube in the car. If the speed of the car past a
particular portion of track is to be the same for all cars at all
times the brackets or stands carrying the reaction wheels may be
fixed to the crossties at an angle selected according to the
desired speed. However, in any complex transportation system it is
necessary that the cars be stopped at certain stations such as
loading or unloading stations or in storage areas, that the speed
of the cars be selected according to the areas through which they
are passing, and that the car be accelerated or decelerated as
necessary to provide safe merging or switching of a car from a side
track onto a main line when there is substantial traffic on the
main line. Stopping of the car, reversing and speed changing is
effected by pivoting the reaction wheel stands about vertical axes
to positions corresponding to the desired speeds and directions of
travel. This pivoting of the reaction wheels may be entirely in
response to an external signal or it may be in response to the
combination of an external signal and a feedback signal
corresponding to the position of the car. Several such systems are
schematically illustrated in FIGS. 12 and 13.
Referring particularly to FIG. 12 a pivoted reaction wheel assembly
92 is provided with a first arm 93 that is connected through a link
94 to an air cylinder or similar linear motor device 95. The arm 93
is normally pulled to the high speed position by a spring 96 and is
drawn to its low speed position by the linear motor 95 in response
to an external signal applied through a control device 97. The
control device 97 may be responsive to signals in the nature of
railroad block signals in the event large spacing is required
between cars, or it may be any type of a stop signal for a loading
or unloading station or, in fact, any signal that requires a
reduced speed of operation of the car.
The reaction wheel assembly 92 has a second arm 98 which, in the
event a car must be stopped precisely at a given point, is provided
with a hook 99 adapted when extended to engage a depending lug or
other member 100 on the car. The hook 99 is pivoted at the end of
the arm 98 and is moved to the left or right by an air cylinder or
similar linear motor 101. In this particular arrangement, when a
car is to be stopped at the station controlled by the reaction
wheel assembly 92 the linear motor or air cylinder 95 pivots the
reaction wheel assembly 92 to a low speed position so that the car
approaching the station is decelerated rapidly and advances at a
slow or creeping pace. This continues until the depending member
100 engages the hook 99 at which time the forward creeping motion
of the car pulls the arm 98 to rotate the reaction wheel assembly
92 into exact parallelism with track resulting in zero speed.
Should the inertia of the car cause it to overrun the desired
stopping position the arm 98 and reaction wheel assembly 92 is
pulled past the zero speed position and the car then moves backward
until the reaction wheel assumes the precise zero speed
position.
It is desirable, particularly if the cars can approach the station
at a high speed to provide a decelerating zone ahead of the
station. This is provided by link 102 having one end pivotally
connected to an intermediate point of the arm 98 and that has, at
its other end, a lost motion connection to a pin 103 on an arm 104
of the next reaction wheel assembly 105. When the reaction wheel
assembly 92 is pivoted to its approximately zero speed position the
next reaction wheel assembly 105 is moved to a low speed position
to provide the decelerating zone ahead of the station.
It may be desirable to include more than one additional reaction
wheel assembly in the decelerating zone in which case another link
similar to the link 102 is used between the reaction wheel assembly
105 and the next reaction wheel assembly along the track. This may
be continued as far as necessary to provide any length of
deceleration zone. Since each reaction wheel assembly is rotated a
fraction of the amount that the previous one is rotated the car
velocity as it travels through such a zone is reduced in increments
which may be approximately equal. Since the link 102 need transmit
tension forces only a length of wire rope or chain may be
substituted. Similarly a smooth rod which is allowed to slide
through a pin corresponding to the pin 103 may provide the lost
motion connection.
It is quite possible in many loading and unloading situations that
a series of cars accumulate at the approach to a station. This is
commonly called queuing. In this situation it is desirable as soon
as a car is stopped at the reaction wheel assembly 92 that the next
succeeding assembly wheel 105 then be pivoted or rotated to its
zero position. This is accomplished by a limit switch device or car
detector 106 adapted to contact the car and initiate operation of a
linear motor 107 that is connected to an arm 108 of the next
reaction wheel assembly 105. This pivots the reaction wheel
assembly 105 to its zero speed position so that a second car
approaching the station will be stopped before it runs into the
first car. The lost motion provided by the slot in the link 102
allows the second reaction wheel assembly 105 to go to its zero
speed position without interfering with the preceding reaction
wheel assembly 92. Additional car detecting devices and linear
motors may be provided for succeeding stations of the queuing
line.
When the first car is to be released a signal transmitted to the
control 97 causes the hook 99 to be withdrawn from the member 100,
the air cylinder 95 to be released and the reaction wheel assembly
92 pivoted by the spring 96 to its full speed position. The car
then leaves the first station in the line. This releases the car
detecting limit switch 106 so that the second car is then
accelerated. Whether or not the second car is stopped in the first
position depends upon whether or not the control 97 is actuated
after the first car has left and before the second car reaches the
stopping position. The same action takes place on succeeding
stations along the queuing line so that release of the first car
causes all of the remaining cars to advance at least one
station.
In some cases it is desirable that the car approach a station at a
fixed speed and that it arrive at the station at a fixed time in
relation to other events or operating mechanism. The mechanism
illustrated schematically in FIG. 13 provides this type of
operation. As shown in this figure a roller chain 110 passes around
a course that includes five guide sprockets 111-115. The guide
sprocket 112 is driven by drive chain 116 engaging a duplicate
sprocket carried on the same shaft as the sprocket 112. The
sprockets 112 and 114 are carried on fixed axles which also carry
arms 117 and 118. The sprockets 111 and 115 are carried on the ends
of arms 117 and 118 respectively. Furthermore, the arms 117 and 118
are connected with a drag link 119 which at its center is connected
to an arm 120 of a reaction wheel assembly 121. The assembly is
normally rotated to its zero speed position by a tension spring
122, the arm being stopped in or near the zero speed position by
the engagement of the arm 120 with a stop 123.
The chain 110 carries dogs 124, 125 either of which may engage a
depending member or lug 126 carried on each of the cars. In this
arrangement as a car comes into the station it meets the zero speed
positioned reaction wheel assembly 121 thus decelerating the car.
This continues until one of the dogs 124, 125 engages the lug 126
on the car. When the dog 125 engages the lug 126 the chain between
the sprockets 115 and 111 is retarded thus rotating the arms 117,
118 and 120. This pivots the reaction wheel assembly 121 toward its
full speed position. This rotation of the reaction wheel assembly
121 continues until the velocity of the car equals the velocity of
the chain 110. Any tendency of the car to run faster than the chain
results in the spring 122 turning the reaction wheel assembly 121
toward a slower speed position thus decelerating the car and any
tendency of the car to lag behind results in a movement of the arm
120 and reaction wheel assembly 121 toward a higher speed position.
Thus the car is accurately driven at a speed and timing
corresponding to the speed and timing of the dogs 124 or 125 on the
drive chain 110. Obviously by proper mechanical connections the
drive chain may be synchronized to any external mechanism with
which the car movement must be synchronized.
One example of the use of the structure shown in FIG. 13 is in
advancing the cars into an elevator that lifts the cars one at a
time from one level to another level.
A typical example of a queuing line is illustrated in FIG. 14 which
shows the arrangement for advancing cars from a branch line onto a
main line. As shown cars normally travel along a main line 130 in
the direction of the arrow 131. Cars from a loading station or
storage area approach along a branch line 132.
As each car moving along the main track 130 passes a car detector
133 a signal is delivered to a timer 134 which through controls
similar to the control 97 sets the last station 135 to the stop
condition. The car detector is located far enough from the junction
of the main and branch tracks so that a car starting from rest at
the station 135 may safely enter the main line ahead of a car just
ready to pass the detector 133. The timer 134 is set to deliver a
stop or hold signal to the control at the last station 135 for a
time interval long enough for the car on the main line to reach the
junction ahead of a car on the branch line that passes the last
station 135 just after the timer times out and restores the station
135 to its "go" condition. The timer 134 is reset for a new timing
interval each time the car detector 133 operates, regardless of
whether or not a timing interval is in progress.
The branch line may have a number of stations, interconnected as
shown in FIG. 12, to accommodate a number of cars on the branch
line until a break or gap in the traffic on the main line
occurs.
If it is anticipated that the traffic on the main line 130 may be
so heavy that the probability of long enough gaps in the traffic
for admitting cars from the branch track is small, means may be
employed to create such gaps. This may be done, as indicated in
FIG. 15, by dividing the main track ahead of a junction into a
series of zones including a high speed zone A, a deceleration zone
B, and two consecutive variable length, variable speed zones C and
D, the zone D extending to the car detector 133.
As long as the branch track or siding 132 is vacant, all of the
zones are set for high speed and the traffic flow is not disturbed.
When a car detector 136 on the branch line 132, which detector may
include a timer, indicates that a car is present and has waited a
predetermined time, the first reaction wheel assembly in zone C is
turned to a slow speed position. This provides the deceleration
zone B, a minimum length low speed zone C and a long high speed
zone D.
Then, in sequence, at a rate slightly less than the high speed of a
car, successive reaction wheel assemblies in zone D are moved to
slow speed position thus extending zone C and shortening zone D.
This continues until zone D vanishes. As soon as the leading car in
the extended zone C reaches the end of that zone all of zones B, C
and D are returned simultaneously to high speed operation. The
signal to return to high speed operation may be generated in a car
detector located at the end of extended zone C and controlling a
signal circuit that is completed when the reaction wheel assembly
at that point is in its low speed position and a car arrives at
that point.
This operation creates a gap or break in the main line traffic
since any cars in zone D proceed at high speed without delay while
any cars in zones B and C proceed at slow speed, thus opening up a
gap between the last car in zone D and the leading car in zone C.
If the low speed is half the high speed the maximum gap thus
produced in the traffic flow downstream from zone D is equal to the
combined lengths of zones C and D. Thus the car detector 133 should
be located downstream from the end of zone D by this distance.
If the branch line traffic is moderate to heavy, zone C and D may
be quite long so that the created gaps are longer and a queue of
cars from the branch line may enter each gap.
The gap may be shortened when the maximum length is not needed by
restoring zone C to high speed as the car detector 136 on the
branch line indicates that the line is vacant.
The sequential transfer from high to low speed and the simultaneous
return to high speed is effected, for example, by employing a
moving contact, such as a timed stepping switch, to sequentially
energize a series of relays, each of which seals or latches in its
on condition, one for each reaction wheel assembly in zones C and
D. The relays, either through solenoids or through solenoid valves
are air cylinders pivot the reaction wheels to their slow
positions. The reaction wheels are simultaneously returned to their
high speed positions by breaking the relay holding circuit or
unlatching the relays. Such control devices are well known and
therefore not illustrated in the drawings.
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