CA1134329A - Bulk material handler and feeder - Google Patents

Abstract

BULK MATERIAL HANDLER AND FEEDER
ABSTRACT
A bulk material feeder has two rollers, at least the lower of which is driven. Strip material is threaded around the side of the upper roller toward the direction of feed, between the rollers, around the said of the lower roller opposite the direction of feed and to downstream machinery spaced from the feeder. Roller spacing is greater than material thickness precluding compression of the material. Feed is produced by fric-tion between the roller and material only. Feed rate is greater than usage thereby producing a depending loop between the feeder and the downstream machinery.
In one embodiment, increasing loop size decreases material and roller contact, causing relative slippage and a discontinuance of feed. In another embodiment, both rollers are driven and loop size is limited by a photoelectric device and associated control circuitry.

Description

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Description Bulk Material Handler and Feeder :, .
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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-2-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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~.~3~3~9 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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3~3~9 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 3~3;~ ~

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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-8- ~' 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 '', :

~L~39;~9 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 : ..
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 : ' . .. . - .. , . ,, , . ,. :;

~3~3Z9t 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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Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. 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 verti-cally spaced along said frame, said rollers being sepa-rated 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 lower roller being frictionally engaged to feed said strip material toward said support.

2. The handler of claim 1 further including means to simultaneously rotate said upper roller.

3. The handler of claim 2 wherein said lower roller is rotated faster than said upper roller.

4. The handler of claim 1 wherein said strip material is driven toward said support at a higher rate than said strip material is removed from said support for said subsequent processing operations thereby pro-ducing a depending loop of material between said lower roller and said support.

5. The handler of claim 4 further including means for rotating said upper roller, and said lower roller is rotated faster than said upper roller.

6. The handler of claim 5 further including means for detecting when said loop depends a predeter-mined distance and means for discontinuing material feed when said loop has depended said predetermined distance.

7. The handler of claim 6 wherein said detection means includes a photoelectric device located below the level of said support and responsive to an energy beam directed along the path of said strip from a point below the level of said support, said device including means for stopping rotation of said rollers when said beam is prevented by said loop from reaching said device.

8. The handler of claim 4 further including means for reducing said frictional engagement and dis-continuing material feed when said loop depends a predetermined distance.

9. The handler of claim 8 wherein said means for reducing engagement includes maintaining said loop free in a hanging state between said lower roller and said support whereby increasing dependency and size of said loop reduces the arc of contact between said strip material and said lower roller thereby reducing said frictional engagement to a point where slippage between said lower roller and said material results in stopping the feed of material by said lower roller.

10. The handler of claim 1 wherein an out-wardly projecting arm extends from said frame for initially receiving said strip material and directing said material to said upper roller.

11, The handler of claim 1 wherein means are provided for detecting either a break in the strip of material or the end of the strip of material and stopping the rotation of the roller when tripped by said break or by said end.

12. The handler of claim 1 wherein said upper roller is freely rotatable on said frame.