Note: Descriptions are shown in the official language in which they were submitted.
O~L~
RESTRICTING BRACKET FOR AUTOMATIC TRANSPORT
SYSTEM
The invention relates generally to automatic
transport systems, and deals more particularly with an
improved automatic transport system of the type having a
guide portion which slopes~downwardly and free traveling
carriers which ride on the guide portion, the improvement
comprising a device whlch limits the forward travel of
the carriers on the downwardly ~loping guiae portion and
on other non-sloping guide portions.
Automated transport systems of the type with
which this invention' is concerned may be used in a gar-
ment making plant to carry workpieces to a series of work
stations where various work operations are performed or
to storage ~ites. Such a transport system is disclosed
in United States Patent No. 4,615,-2~`3,
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filed 12-19-84 by Roald Paul Nymark and Harold Osthus,
assigned to the assignee of the present invention and
hereby incorporated hy references as part of the present
disclosure. The aforesaid system is highly automated and
includes free traveling trolleys which carry worXpieces
and a rail network on which the trolleys ride, which
network comprises a main rail and subsidiary rail loops.
The main rail guides the trolleys to the subsidiary rail
loops and the subsidiary rail loops guide the trolleys to
and from the work stations or serve as storage sites.
The rail network also includes an endless, moving chain
adjacent the main rail and pushers attached thereto and
spaced along the chain to engage the trolleys and propel
them along the main rail and switches for transferring
the trolleys to and from the subsidiary rail loops.
Each of the subsidiary loops has a gap adjacent
the main rail and, likewise, the main rail has a gap
adjacent each subsidiary loop, and the associated switch
comprises a short section of rail and an actuator
apparatus which is capable of moving the rail section
from a first position bridging the gap in the main rail
to a second position bridging the gap in the subsidiary
loop and vice versa. To switch a trolley from the main
rail to a subsidiary rail loop, the rail section is
initially located in the gap of the main rail and
receives a trolley propelled by a pusher. Then, the
actuator apparatus moves the rail section, while the
trolley is received on it, to the gap in the subsidiary
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loop and the pusher propels the trolley onto a rail of
the subsidiary rail loop.
Another trolley and rail system comprises a main
rail, subsidiary rail loops, and a switch adjacent each
subsidiary loop, free traveling trolleys which ride on
the rails, pushers for the trolley. Each switch
comprises a pair of pivoting fingers having their pivot
axis on the main rail. When both pivoting fingers are
closed, a trolley is guided over the switch along the
main rail and, when one pivoting finger is opened, a
trolley is guided toward or received from the subsidiary
loop.
In both types of trolley and rail systems
described above, a computer is utilized to control the
routing of the trolleys to the subsidiary loops and does
so in part by controlling the switching mechanisms
associated with them. To perform a proper switching
operation, the movement of the switch must be timed with
the arrival of the designated trolley, and the computer
estimates the position of the trolley primarily from the
location of its pusher. With either type of switch
described above, and with other types of switches, there
are discontinuities in either the main rail or the
subsidiary loop at all times which discontinuities make
it possible for a trolley to inadvertently fall off the
rail network.
To compound the problem, it is sometimes
advantageous to locate subsidiary loops used for storage
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several feet above the floor to conserve workspace so
that the space beneath the storage loops can be used for
worX stations, other storage sites, walk-ways, or other
purposes in which case at least one portion of the rail
network slopes upwardly and at least one portion slopes
downwardly. Also, such automated transport systems may
occupy two floors of a factory in which case at least one
portion of the rail network slopes upwardly and at least
one portion slopes downwardly to link the two floors. If
a free traveling, unrestricted trolley rides on such a
downwardly sloping portion of a rail network, the trolley
rolls ahead of its pusher and descends along the sloping
rail portion to the rear of the next pusher, typically
3-5 feet downstream. If the downwardly sloping rail
portion is located just upstream of a switch scheduled to
divert the trolley, and the pusher does not catch up to
the trolley before reaching the switch, the trolley may
roll past the switching mechanism before the computer
directs the switch to move to the subsidiary loop and
hence avoid the switching operation. Also, it is
possible in the patent pending system for the trolley
immediately in front of the errant trolley to be sched-
uled to divert to the subsidiary loop and for the errant
trolley to fall off the rail through the gap left when
the switching mechanism attempts to switch t~e trolley in
front, or for the errant trolley to be inadvertently
switched later on to an unscheduled work station or
storage site or to jam the system.
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There ~re other ~actors besides the downward
slope of a rail portion which cause a trolley to advance
ahead of its pusher and potentially cause problems of the
types described above. For example, an air draft from an
open door or window may act upon garments suspended from
the trolley as a wind acts on a sail, a person may
inadvertently brush against a trolley or the associated
workpieces, or an operator loading a trolley onto the
rail may inadvertently push the trolley forward.
Accordingly, a general aim of the present
invention is to improve a transport system of the type
having free traveling carriers, a guide for the carriers,
and pushers for the carriers so that the carriers cannot
advance much ahead of their associated pushers when urged
in that direction by gravity or other external force.
A more specific aim of the invention is to
provide such an improvement which is simple in
construction and use and does not appreciably interfere
with the routing of carriers through the system.
Other aims and advantages of the invention will
become apparent from the following detailed description
and accompanying drawings.
The invention resides in a restricting means for
a transport system of the type having a plurality of free
traveling carriers, a guide for the carriers, and means
for propelling the carriers along the guide. According
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to one feature of the invention, the propelling means
includes an endless, moving chain and pushers which
extend from the chain and drive the carriers, and the
restricting means comprises a plurality of bracXets which
extend downwardly from the chain, one in front of each
pusher defining a carrier pocket for containing a
carrier. According to another feature of the invention,
each of the brackets is pivotally mounted on the chain
within limits defining a loading position to admit a
carrier into the carrier pocket and a blocking position
to prevent the carrier from escaping from the pocket.
According to another feature of the invention,
each restricting bracket is releasably secured to the
chain.
Fig. 1 is a top view of a automated transport
system which utilizes the invention.
Fig. 2 is a perspective view of a section of the
automated transport system of Fig. 1.
Fig. 3 is a side view of another section of the
automated transport system of Fig. 1.
Fig~ 4 is a rear sectional view of a trolley, a
propulsion track, a restricting bracket and a pusher of
the automated transport system of Fig. 1.
Fig. 5 is a side view of a restricting bracket
of the automated transport system of Fig. 1.
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Fig. 6 is a top view of the bracket of Fig. 5.
Fig. 7 is an end view of the bracket of Fig. 5.
Fig. 8 is a side view of a section of a chain
within a propulsion track of the automated transport
system of Fig. 1 and shows the restricting bracket of
Fig. 5.
Fig. 9 is a top view of Fig. 8.
Fig. 10 is a side view of a downwardly sloping
portion of a rail network of the automated transport
system of Fig. 1.
Turning now to the drawings, Fig. 1 illustrates
a automated transport system generally designated 5 which
utilizes the invention. The system includes a master
computer 8, a propulsion track 10 having pushers 15,15
extending downwardly therefrom, a motorized drive unit 3
for the propulsion track 10, a main rail 12 situated
beneath the propulsion track 10, free traveling trolleys
14,14 riding on the rail 12 and propelled by the pushers
15,15, and subsidiary loops 16,16, 32,32, 17 and 19
located along the main rail some of which are paired.
Each of the subsidiary loops 16,16 and 32,32 leads to and
from a work station 33 or 35 and the subsidiary loops 17
and 19 are used for storage. The automated transport
system further includes three position switches 25,25 for
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routing the trolleys between the main rail and each pair
of subsidiary loops or directly between the subsidiary
loops of a given pair, and two position switches 27,27
for routing the trolleys between the main rail and each
unpaired subsidiary loop or a diversion rail 31. The
system of Fig. 1 includes a total of nine subsidiary
loops but can easily be modified to include more or fewer
loops if desired.
Fig. 2 illustrates a section of the automated
transport system 5 of Fig. 1, and shows the main rail 12,
the propulsion track 10 situated above the main rail and
a pair of subsidiary loops 16 and 32. One of the
trolleys 14, specifically identified as 14a, rides on the
main rail 12 and is propelled by one of the pushers 15
specifically identified as 15a. Pusher 15a is one o~ a
series of identical pushers uniformly spaced along and
extended downwardly from the track 10. The pusher l5a
itself is driven by an endless, moving chain (Figs. 8 and
9) located within the overhead propulsion track 10, and
in Fig. 1, the pusher is shown moving trolley 14a toward
the subsidiary loop 16. A series of restricting brackets
70,70 also extend downwardly from the track 10,one in
front of each of the pushers 15,15. The subsidiary loop
16 includes a looping rail 28, a stop 38, and an elevator
54, and the oppositely-disposed subsidiary loop 32 is a
mirror image of the loop 16.
The main rail 10, subsidiary loop 16, and
subsidiary loop 32 each have a gap laterally aligned with
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one another, and the switch 25 includes a straight
section of rail 24 and an actuator apparatus 18
controlled by the computer 8. The main rail 12, the rail
section 24, and the looping rails 28 and 30 preferably
are made of piping. Actuator apparatus 18 is responsible
for moving the rail section 24 laterally between a first
position ~as shown) briAging the gap in subsidiary loop
16, a second position bridging the gap 29 in main rail
12, and a third position bridging a gap (not shown) in
subsidiary loop 32.
To transfer a trolley from the main rail to the
subsidiary loop 16, the rail section 24 is initially
positioned in the gap of the main rail and one of the
pushers 15 pushes a trolley from the main rail 12 onto
the rail section 24. Then, the computer directs the
actuator 18 to move the rail section 24 toward the gap in
the subsidiary loop 28. While the trolley is on the rail
section 24, the pusher 15 continues to engage the trolley
because the pusher is wide and when the rail section
reaches the gap in the subsidiary loop 16, the pusher
pushes the trolley onto an entrance portion 36 of the
looping rail 28. Then, the actuator 18 returns the rail
section 24 to the main rail 12 so that other trolleys can
proceed down the main rail or be switched by the rail
station.
The looping pipe 28 of the subsidiary loop 16
slopes downwardly from its entrance 36 so that a trolley
rolls along it by gravity. About midway along the
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looping rail 28 is the stop 38 which includes an upper
gate and a lower gate (neither gate shown). The stop 38
is shown backing up trolleys 14b-d at its upper gate,
trolley 14b being first in line. There the trolley 14b
waits until an operator 42 is ready for it and presses a
button on control box 50 to open the upstream gate of
stop 38 and allow it to roll to the downstream gate
located at the base of the stop 38 adjacent the operator
as has done trolley 14e previously.
In Fig. 2, the operator 42 is shown sewing a
workpiece 46 carried by the trolley 14e with sewing
machine 45, and when done with all the workpieces
suspended from the trolley, he or she may push a button
on control box 50 to cause the downstream gate of stop 38
to open and allow trolley 14e to roll by gravity toward
the elevator 54.
At the base of elevator 54 is another stop (not
shown) to collect trolleys while they wait their turn to
be reloaded onto the main rail 12. When the master
computer senses an absence of trolleys on the rail
section 24 and on a portion of the main rail 12 just
upstream of the rail section 24, the computer directs
actuator 18 to move rail section 24 to subsidiary loop 16
and activates the elevator stop and elevator 54 to admit
a trolley into an elevator car, which car comprises a
slotted track section 57 for receiving the trolley.
Then, the computer directs the elevator to elevate the
trolley as it has done to the trolley 14 indicated as f
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shown in Fig. l, and after the trolley reaches the top of
the elevator 54, the next arriving pusher pushes the
trolley from the slotted track section 57 onto the rail
section 24.
In one mode of operation, after the rail section
24 receives the trolley, the computer directs actuator 18
to draw the rail section 24 back into line with main rail
12 and after a few more moments of being pushed, the
trolley returns to the main rail 12 and proceeds
downstream, usually to another subsidiary loop and an
associated work station.
Fig. 3 illustrates that the subsidiary loops 17
and 19 are substantially elevated relative to the
subsidiary loop 16 and the associated work station, for
example, eight feet higher than the subsidiary loop 16.
This is done to conserve work space: the storage loops
and the stored trolleys and work pieces 50 are elevated
enough to allow people to walk or work underneath, to
allow other workpieces or equipment to be positioned
underneath, or to allow other functions to be performed
underneath. A downwardly sloping portion 90 of the rail
12 leads from the subsidiary loop 19 to the subsidiary
loop 16.
Fig. 4 shows a rear view of the trolley 14
indicated as n, a pusher 15 indicated as c which engages
it, and the restricting bracket 70. The trolley 14n has
two wheels 144 and 146 which ride on one of the rails of
the system 5. The wheels attach to the inside of an
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upper hook-shaped portion 141 of the trolley and straddle
the rail upon which they ride to provide balance. At the
top of trolley 14n is a T-shaped crown portion 66 which
is the portion of the trolley actually engagea by the
pusher 15c. The pusher 15c has an inverted T-shape and
extends downwardly from the inside of the propulsion
track 10 behind the trolley 14n (relative to the
direction of trolley movement on the main rail), and
within the track, an endless, moving chain 150 attaches
to the pusher 15c and drives it. Similarly, the
restricting bracket 70 is attached to and driven by the
chain 150, which bracket is situated în front of the
trolley 14n.
Focusing now on the invention, Figs. 5, 6 and 7
illustrate the restricting bracket 70 which is formed
from metal or plastic and comprises a stem portion 72, a
neck portion 74, a throat portion 79, and a curved head
portion 76 having a back portion 82 and a pivot recess
78. By way of example, the bracket 70 is made of cast
aluminum and has the following dimensions:
A = .25 (all dimensions in inches unless
otherwise indicated)
B = 3.25
C = 2.59
D = 0.2
E = 1.625
F = .220
G = .913
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H = .310 (Diameter)
I = 1.0
J = .332 (Diameter)
K = 30 Degrees
L = .563 (Radius)
M = .312
N = 1.625
0 = 9 Degrees
P = .188
Q = .563
R = .125 (Radius)
Also, the vertical distance between the chain lS0 and the
rails 12 and 24 is such that when the bracket is
suspended from the chain, it reaches just below the crown
portion lS0 of a trolley 14 which it restricts.
Figs. 8 and 9 show the chain 150 of the propul-
sion track 10 and the restricting brackets 70,70. The
chain includes links 170,170 and 172,172, the link 170
being connected to the link 172 via a horizontal pin 176
and a vertical pin 178 to allow relative vertical and
horizontal pivoting as required to follow the course of
the main track 10. The chain 150 further includes
vertical wheels 180,180 mounted on axles 80,80 and
horizontal wheels 182,182 mounted on axles 184,184 which
wheels guide the chain within the main track 10. The
bracket 70 releasably attaches by a snap fit to the
horizontal axle 80 of the chain with the pivot recess 78
engulfing the axle at the throat 79 and the bracket 70
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pivoting on the axle. Because of the de~ign and
dimensions of the bracket 70 described above, the bracket
70 balances it~elf in the orientation shown in Fig. 8
with the bracket ~tem portion 72 angled at approximately
45 degree~ relative to a horizontal plane.
In the illu~trated embodiment, one of the
brackets 70,70 is installed in front of each associated
pusher, and by way of example, the separation distance is
approximately eight inches. This space defines a trolley
pocket 86 and allows plenty of room to house one trolley,
yet is short enough to allow the computer to keep
reasonably apprised of the trolley's whereabouts.
The bracket 70 may pivot rearwardly (counter-
clockwise) to a trolley loading position where the stem
portion 72 is oriented approximately horizontal and abuts
the link 88 of the chain 150, and may pivot forwardly
(clockwise) to a trolley ~locking position where the stem
portion is oriented approximately vertical and the back
portion 82 of the head portion 66 abuts a spacer 84. To
load a trolley into the trolley pocXet 86, the trolley
may be inserted directly over a portion of the rail
within the pocket or inserted on a portion of the rail in
front of the associated restricting bracket 70 and either
held in place until the bracket 70 overtakes the trolley
and pivots upwardly to the trolley loading position to
admit it into the pocket, or slid rearwardly until it
contacts the bracket, forces it to pivot upwardly, and
enters thc pocket. Alternately, the trolley may be left
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on the rail to await the arrival of the next bracket 70
in which case, when the bracket 70 reaches the trolley,
the bracXet pivots upwardly to admit it, the inertia of
the trolley being large enough to cause the bracXet to
admit it instead of pushing it ahead. The 45 degree
balancing orientation of the bracket facilitates the
admissior. of a trolley into the trolley pocket from a
position initially forward of the bracket as described
above.
Fig. 10 shows the downwardly sloping portion 90
of the rail 12 leading to the subsidiary loop 16
indicated as s and illustrates one role of the
restricting brackets 70,70. The trolley 14 indicated as
o rides on the sloping rail portion 90 and has rolled
ahead of the associated pusher 15 indicated as o by
gravity to the bracket 70 indicated as o, which bracket
has pivoted slightly forward due to the slope of the rail
portion 90 and the weight of the trolley 14-o to its
trolley blocking position. If not for the bracket 70-o
it would roll all the way to the rear of the pusher 15
indicated as p. The trolley 14 indicated as q is shown
riding on the beginning of a horizontal portion 92 of the
rail 12 but previously rode on the sloping portion 90.
At which previous time, the trolley 14-q forwardly
advanced to the rear of the restricting bracket 70
indicated as q and when th`e trolley 14-q reached the
beginning of the horizontal portion 92, as shown, its
momentum maintained it somewhat ahead of the pusher 15
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indicated as q. Afterwards, the trolley 14-q will
gradually recede from the bracket 70-q as its momentum
dissipates until it is re-engaged by the pusher 15-q,
just as the pusher 15 indicated as r has caught up and
re-engaged the trolley 14 indicated as r.
To conserve work space, the subsidiary loop 16
indicated as s and the associated work station 33 are
located near the base of the sloping rail 90.
Assuming that the trolley 14-r is programmed to
enter the loop 16-s, shortly after the pusher 15-r passes
over the upstream end of the rail section 24 of the
switch 27, the computer directs the actuator apparatus 18
to transfer the rail section 24 to the gap in the
subsidiary loop 16-s. The distance from the pusher 15-r
to the bracket 70 indicated as r plus the distance that
the pusher advances while the trolley is laterally
transferred is less than the length of the rail section
24, so the trolley will remain on the rail section 24
during switching and not forwardly advance beyond the
rail section regardless of where the trolley is located
within the trolley pocket 86.
Note that if the restricting bracket 70-r was
not installed, the trolley 14-r may have rolled much
further ahead of the pusher 15-r and onto the rail
section 24 much before the arrival of the pusher 15-r,
and unless stopped by corrugations 71 on.the rail
section, bypass the switching operation altogether. ~lso
without the bracket 70-q, the trolley 14-q may have
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rolled all the way to the rear of the pusher lS-r and
when the rail section 24 moves laterally to attempt to
switch the trolley 14-r, the trolley 14-q may fall off
the main rail through the gap left by the rail section 24
or jam or be switched by the switch 27.
After the trolley 14-r circulates around the
looping rail 28 of the subsidiary loop 16-s, it is
carried upwardly by the elevator 54, met by the rail
section 24, and pushed by the next pusher onto the rail
section 24 to be carried toward the main rail. Since the
bracket 70 associated with the pusher is forward of the
pusher, when the rail section 24 arrives in line with the
main rail, the trolley is received within the respective
trolley pocket 86 and can proceed downstream, or be
laterally transferred to the subsidiary loop 18 as
directed by the computer.
It is possible, although unlikely, that when a
trolley is first engaged by the pusher 15 at the top of
the elevator, it is bumped forward of the pusher along
the rail section 24 or rolls forward by gravity on the
rail section 24 due to an inadvertent slope. The
corrugations 21 on the rail section 24 stop the trolley
before it falls off the rail section. IE the trolley 14
rolls eight inches ahead of the pusher when the rail
section 24 arrives in line with the main rail, the
trolley will strike the bracket 70 broadside. However,
due to the slope of the stem 72 of the bracket 70, the
bracket will usually pivot upwardly and eventually admit
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the trolley. It is also possible for the trolley to
pause when it strikes the bracket, tipping slightly on
the rail section 24, until the bracket 70 advances
forward of it due to the forward movement of the chain
150 and then enter the trolley pocket. If the trolley
rolls further than 8 inches ahead of the pusher it will
be located ahead of the restricting bracket, but will
soon be automatically engulfed by it, the corrugations 71
ensuring that the bracket 70 overtakes it.
By the foregoing, a restricting bracket for a
automated transport system has been disclosed embodying
the present invention. However, numerous modifications
and substitutions may be made without deviating from the
scope of the invention. For example, if desired, the
bracket 70 may be manufactured integral with the chain so
that it is not readily attachable or detachable from it.
Also, if desired, the tip of the stem 72 of the bracket
70 may be widened as an inverted T-shape in the event
that the bracket 70 is utilized with a trolley which has
a vertically narrow top instead of the wide, T-shaped
crown 66. It is also possible to put bevels in the side
edges of the stem 72 of the bracket 70 so that in the
event a trollev strikes the stem 72 broadside, the bevels
will facilitate the upward pivoting of the bracket 70 to
admit the trolley into the pocket 86. Also, the
restricting bracket 70,70 can be used in a rail network
having sloped portions which interconnect two floors.
Therefore, the invention has been disclosed by way of
illustration and not by limitation.
