Note: Descriptions are shown in the official language in which they were submitted.
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Description
Bulk Material Handler and Feeder
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Technical Field
This invention relates to machines which
positively and variably feed material from bulk
storage to downstream processing machinery.
Background Art
Many machines or machine processes utilize
bulk material in the form of strips wound in a coil
or stored in a container as a starting point ox
operations which result in a finished product. SUch
machinery is commonly used in conjunction with an
apparatus which feeds material from its storage
configuration into the downstream machine or machines.
This feed apparatus must be capable of positively
feeding material to downstream machinery, adapting
to variable material requirements, and should not
unduly stress the material as it is being fed.
EY~isting feed apparatus usually includes
at least one set of two rollers which rotate in
opposite directions and compress the material to be
fed therebetween in order to provide a positive drive~
Ater exiting these rollers, the material falls into
a loop before entering subseque~t machinery. The ~-
feed rate is controlled by means of a so called
machanical "dancer" which consists of two or more '~;
limit switches positioned to i~tercept the material
loop. Operation of these limit switches pro~ides
signals which control the operation of a drive motor ~`
connected to the rollers~ On-off operation of the
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drive motor results in a relatively constant loop size
and variable material feed.
This type of machinery has not proven entirely
satisfactory since the rollers induce undesirable com-
pression forces in the material, may subject the
material to tension between pairs of rollers, and may .
cause material breakage if the material is momentarily .
not free to feed from storage. Also, such machinery is
often unduly large and cumbersome and is relatively
unsafe in that an operator, or the like, can come into
contact with the moving material and, since it is
tacky, i~ can catch the clothing or parts of the
operator and pull the clothing and/or the operator into ;~
the machine.
The present invention is directed to over-
coming one or more the the problems as set forth above.
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Disclosure of Invention
The present invention provides a handler for
directing and feeding strip material toward a support
horizontally spaced from said handler for subsequent
processing operations comprising a frame; upper and
lower rollers mounted on and vertically spaced along
said frame, said rollers being separated one from the
other a distance greater than the thickness of said
strip material; and means for rotating said lower
roller; said strip material being threaded around the
upper roller in a direction toward said support,
between said rollers, around said lower roller in a
direction away from said support, and to said support;
said strip material and said Iower roller being fric-
tionally engaged to feed said strip material towardsaid support.
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/ Brief Description of Drawings
Fig. l is a front elevation of an embodiment
of the present invention.
Fig. 2 is a side elevation of the embodiment
of the invention shown in Fig. l; and
FigO 3 is a side elevation of another embodi-
ment of the present invention.
Best Mode for Carrying Out the Invention
10Referring to the drawings, and particularly
Figs. l and 2, a bulk material handler and feeder lO is
illustrated which includes a primary drive roller 12
and a secondary roller 14 mounted in a vertically
spaced arrangement on a frame 16. The ends of the
15rollers 12 and 14 include sprockets 18 and 20 driven
through a chain 22 by a motor 24 and drive sprocket 26.
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The chain 22 is so arranged around the sprockets 18
and 20 so as to drive the rollers 12 and 14 in
opposite directions.
The rame 16 further includes an outwardly
projecting arm 28 which pro~ects over a storage con
tainer 30 and terminates .in a guide roller 32.
Bulk material 34 in the form of a strip
is fed over the ro].ler 32, between upstanding center-
ing rollers 36, and around the drive rollers 12 and
14. The material 34 is wrapped counterclockwise
(as viewed in Fig. 2) partially around the primary
roller 12, threaded between the two rollers 12 and
14, and is wrapped clockwise partially around the
lower secondary roller 14.
The strip of material 34 is then fed to
the entrance 38 of a subse~uent processing machine
(not shown) located downstream of the material feeder
10. Loca.ted within the downstream machine is means
to draw the material 34 into the entrance 38 at a `~
particular usage rate. SUch means to draw the
material 34 may be compression rollers gripping
both sides of the material 34.
It is contemplated in this invention that
the usage rate of the downstream machine be known,
and that the speed of the motor 24 and tooth ratio
between the drive sprocket 26 and the roller sprockets
18 and 20 be such that material 34 is fed from the ~
material handler 10 at a greater rate than is used `.
by the downstream machinery~ In addition, the
sprocket tooth ratio of the rollers 12 and 14 is
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such that the secondary roller 14 rotates at a higher
speed than the primary roller 12.
The higher rotational speed of the secondary
roller 14 causes the roller 14 to slip relative to the
material 34, but because there is ~rictional drag be-
t~een the material 34 and the roller 14, there will be
a slight tension on the material located between the two
rollers 12 and 14~ ThiS tension and the tension caused
by the weight of material 34 ramaining in the storage
container 30 will ensure substantial contact between the
material 34 and the primary roller 12 which, in turn, ;
ensures that the material 34 will be fed at a rate e~ual
to the surface velocity of the primary roller 12.
Since material 34 is fed by the bulk handler
10 at a rate faster than it is drawn into the entrance
38, a constant oversupply of material 34 results. This :.
oversupply manifests itself as a hanging loop 40 between
the handler 10 and the entrance 38. TO prevent the
material 34 from simply unwinding off the handler 10
due to the feed differential, a photoelectric device 42
is provided which is used in conjunction with a reflect-
or 44 attached under the entxance 38. The photoelectric "~
device 42 operates by emitting a beam of visible or
infrared energy, depicted by the dotted line 46, which
is directed toward the reflector 44 and reflected backto a sensor 48 loca.ted in the device 42. A suitable
control circuit (not shown) is connected between the
photoelectric device 42 and the motor 24 and operates
to permit the motox 24 to run so long as the beam 46 is .
reflected and sensed by the sensor 48. If the beam 46
is bloclced and prevented from returning to the sensor 48,
the control circuit operates to shut off the motor a4 .
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In this fashion the size of the hanging loop 40
may be maintained at a relatively constant size. As
shown in Fig. 2, as the loop 40 increases in size, it
eventually hangs a distance suf~icient to block the beam
5 46, as illustrated by double phantom lines 40A. As ex- :
plained above, when the beam 46 is broken, the motor 24
will stop and material feed will be discontinued. As
material 34 is drawn into the entrance 38, the loop 40
decreases in size until it reaches approximately the ~;:
position shown by the solid lines 40B. At this point,
the beam 46 is no longer blocked and the photoelectric
device 42 and its associated control circuit w.ill oper-
ate to a.gain start the motor 24. A suitable time delay
is incorporated into the control circuit to allow the
15 loop 40 to vary over a relatively large range thus pre- :
venting continual on-off operation of the motor 24.
At any time that the demand for material into
the entrance 38 is terminated, the loop will move or sa~ :
to the position shown by 40A which will interrupt the
beam 46, will shut down the drive, and will sta.y in that
position until a supply of material is again requixed.
Therefore, as long as the material is continuous (i.e. ~.
not severed or terminated) there will be an automatic
start up of operations when there is a. demand for materi~
al. The feeder is capable of operating a.t optimum
designed speed down to zero speed.
As the material 34 reaches the end of its lengt~
or if the strip of material 34 breaks, it is desirable
that operating personnel be appraised of the situation so
that the material 34 may be replaced and a relatively
constant supply may be fed to the entrance 38O To pro- ;
vide such an alarm and to turn off the bulk handler 10,
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a trip wire 50 is provided which is connected to a
limit switch 52. When the end of the material 34 passes
the upper roller 12, the end will fall free between the ',
two rollers 12 and 14 and fall toward the bottom of the ,'
frame 16. During its fall, the material 34 intercepts
the trip wire 50 which pulls on a switch arm 54 and
actuates the switch 52. Operation of the switch 52 ~'
provides an electrical signal to an appropriate con-
trol circuit which sounds an alarm and stops the motor 24.
A similar bulk material handler lO is
illustrated in Fig. 3 which includes structure
similar to that found in Figs. l and 2 and labeled
identically. The differences be~ween the machine
shown in Fig. 3 and that shown in Figs. l and 2 are
that the upper roller 12' is free running in Fig. 3,
i.e. not driven by the motor 24 and chain 22, and ~'
that the photoelectr`ic device 42 and reflector 44 are ;,
eliminated. The material handler lO of Fig. 3 is
further provided with a chain tensioning sprocket 56.
In the material handler 10 of Fig. 3, the
material 34 is threaded as previously but material
feed rate and the size of the hanging loop 40 is
controlled by the lower roller 14 alone; the upper
roller 12' being free rolling and merely a material
~upport and guide. Control over material feed is
accomplished by variation o~ the contact a,rc length
between the lower roller 14 and the material 34. AS
in the machine of Fig. 1, the material is fed from ;~
the handler 10 at a rate greater than can be utilized
by the downstream machine. Therefore, the size of the
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han~in~ loop 40 will tend to increase as discussed above.
AS the size of ~he loop 40 increases and approaches the
configuration labeled 40A, angular contact between the
material 34 and the rollex 14 will decrease, thus de- ~ -
creasing the length of the material 34 in contact with
the roller 14 and consequently decreasing the frictional
force generated between the material 34 and the roller
14.
When the hanging loop 40 increases approxi- ;
mately to the representation labeled 40A, angular con-
tact between the material 34 and the roller 14 will be
so small that frictional forces between the material 34
and the roller 14 will not be sufficient to overcome
the weight of material hanging ~rom the guide roller 32.
At this point, material feed will stop even though the
drive roller 14 continues to rotate. The drive roller
14 will simply slip relative to the material 34. In
addition to or rather than depending on the weight of
material in the container 30 to provide resistance
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to material feed, the upper roller 12' may be provided
with a frictional brake (not shown) to accomplish the
same purpose.
~ s material is ~rawn into the entrance 38,
the size o~ the hanging loop 40 will decrease and con-
se~uently, angular contact between the material 34 andthe roller 14 will increase. ~t some point between
the two e~tremes labeled 40A and 40B in Fig. 3, this
angular contact will be such that sufficient friction
is generated between the roller 14 and the material 34
to overcome the weight of material hanging from the
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guide roller 32 and its adhesion to layers under itself.
At this point, positive material feed will recommence. :
The configuration of the material 34 between the handler :
10 and the entrance 38 is shown by extreme conditions
5 40A and 40B, and it should be apparent that the hanging :~
loop 40 will not actually vary between these two extremes.
So long as material demand is constant, the hanging loop
40 will reach an equilibrium position at which slippage
between the material 34 and the roller 14 is constant
and the feed rate from the handler 10 is equal to
material usage.
Industrial Applicability
As will be appreciated from the drawings and
foregoing description, a bulk material feed apparatus
is provided which takes up little more space than the
material storage container itself, and, once the drive
is started, the apparatus automa.tically feeds material
when such material is necessary for the operation of
subsequent machinery, is capable of feeding materia].
at a variable rate, and discontinues feeding material
and sounds an alarm when either a break in the stock
or the end of the stock is reached. In addition, the
feed apparatus induces no compression forces in the
material and except ~or a very small tension force
necessary to maintain frictiona.l contact between the
dr~.ver rollers and the material, does not subject the
material tc tensile stresses.
Since the material feed apparatus depends for
its operation on frictional engagement between the
drive rollers and the material, it is contemplated that
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the drive xollers be constructed o~ a material which will
effectively frictionally engage the type of material be-
ing fed~ For example, if the bulk material is rubber or
some other soft composition, the rollers may be made of
S metal or include a metal surface. However, in order to
provide the desired frictional contact in the event
metallic strips are to be ed, the rollers should be
made of, or surfaced with, a softer composition such as
rubber.
An inspection of Figs. 2 and 3 will reveal that
angular contact between the rollers and the material
may be varied by changing the vertical and/or horizontal
spacing between the upper ana lower rollers. SUch ad-
justmants will provide optimal frictional enga~ement
between the material to be fed and the drive rollers.
Other aspects, objects and advantages of
this invention can be obtained from a study of the
drawlngs, the disclosure, and the appended claims.
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