Note: Descriptions are shown in the official language in which they were submitted.
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A ROLLER NORMAL FORCE APPLICATOR FOR BOTTOM ARTICLE FEEDER
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The invention relates to a feeder for serially feeding the bottom
article, such as a sheet of paper, an envelope or a magazine, from a stack of
S such unseparated articles. Specifically, the invention relates to a normal force
applicator, which utilizes a roller, which roller presses on the leading area ofonly a few of the bottom articles in a stack of articles ensuring a reliable feed to
an article separator. The article separator may be, for example, a conventional
friction retard device using a friction retard pad. The individual article thus
10 separated feeds articles to the next processing station.
There are numerous applications in which a bottom feeder to feed
articles serially from an unseparated stack of articles can be used, for example,
to feed sheets of paper serially to a printer or copier or to feed envelopes to a
printer or labeler. Obviously, many more examples could be given. One aspect
15 common to all bottom feeders is the difficulty experienced in reliably driving
and feeding but one article from the set of stacked articles. The reliability ofbottom feeders can be affected by variations in the height of the stack of
articles. For example, where only a few lightweight articles, such as sheets of
thin paper, are in the stack, there may not be enough weight, that is, normal
20 force, on the stack to make the feeder work properly. To alleviate such
problems, a normal force applicator can be used.
Conventional normal force applicators are designed to press down on
the top of the stack of articles to hold the stack down and to provide sufficient
engagement force between the bottommost article of the stack of articles and
25 the bottom feeder. The normal force applicators can be a weighted or spring-
loaded plate1 bail bar or the like. One problem with such normal force
applicators is that they must be removed or lifted out of the way before more
articles can be added to the top of the stack. Also, where the stack is relatively
large, a larger force may be required where the force is applied through the
30 entire stack to ensure proper feeder operation. The invention as claimed is
intended to provide a remedy. It solves the problem of how to provide a reliableserial bottom feeder for articles, which feeder also allows for the convenient
addition of further articles to the top of the stack.
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An aspect of the invention is as follows:
An apparatus for assisting bottom feeding an
article from a stack of articles to a separator, which
comprises:
an input tray for holding a stack of articles,
said input tray having a slot formed therein;
a driven feed belt positioned to protrude through
said slot in said input tray in feeding relationship to
a stack of articles on said input tray;
a normal force applicator roller positioned in
spaced relationship to said driven feed belt to form a
rolling nip therewith, article guide means for guiding
the bottom articles in the stack of articles to said nip
formed by said normal force applicator roller and said
driven feed belt;
means for urging said normal force applicator
roller toward said driven feed belt, said means being of
strength sufficient to allow more than one article to pass
into said rolling nip under the influence of a moving
driven feed belt;
separator means positioned in spaced relationship
to said driven feed belt and positioned to receive articles
passing through said rolling nip, said separator means
being designed to allow the passage of only one article
at a time therethrough.
One way of carrying out the invention is described
in detail below with reference to drawings, which illustrate
only one specific embodiment, in which:
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Figure 1 is an end view looking into the normal force applicator from
the direction of article input.
Figure 2 is a side-sectional view of the normal force applicator of
this invention taken along lines 2-2 of Figure 1 and in addition shows a typical5 friction retard separator.
Figure 3 is a partial side sectional view of the normal force appli-
cator of this invention, which shows how the normal force applicator interacts
with the stack of articles to be fed, the feed belt and the friction retard
assembly.
Figure 4 is a top view of the frame for the normal force applicator of
this invention.
Figure 5 is a top view of the friction retard pad support frame for use
with the present invention.
Referring now to the Figures, an input tray 1 is provided on which a
stack of articles 3 (see Figure 3) is provided. The stack of articles 3 may be, for
example, a stack of paper or envelopes or any suitable article that it is desired
to feed serially to a work station. Protruding through a slot 9 in the input tray 1
in feeding relationship to the stack of articles 3 is driven feed belt 5. Drivenfeed belt 5 is driven in the direction shown by the arrows (see Figures 2 and 3) by
driven feed belt pulleys 7. The means for driving driven feed belt pulleys 7 is not
shown although obviously one of the driven feed belt pulleys 7 could be, for
example, mounted on the shaft of a motor; or, as another example, the driven
feed belt 5 could be driven by frictional contact with a third pulley, and pulleys 7
would not be driven.
The normal force applicator generally designated as 11 includes a
roller support frame 13, which is connected by bolts 15 to base 17. Roller
support frame 13 has formed therein slot 19 (see Figure 4) and aperture 21, bothof which traverse the complete height of roller support frame 13 as shown in
Figure 2. Slot 19 acts as a guide for normal force applicator roller support 23,which is mounted for slidable movement in the space defined by slot 19 and base
17 when it is attached to base 17, Normal force applicator roller support 23 hasformed thereon roller support arms 25 (see Figure 1) between which normal force
applicator roller 27 is mounted for rotation. Normal force applicator roller
support 23 is urged downwardly against driven feed belt 5 by normal force
applicator spring 29 to form a rolling nip 2~ therewith. Normal force applicatorspring 29 in this instance is attached to pin 31 in slot 33 on normal force
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applicator roller support 23 and to pin 35 in slot 37 on roller support frame 13.
Also attached to base 17 is separator generally designated as 16, which in this
instance comprises friction retard pad support frame 39 (see Figure 5). Frictionretard pad support frame 39 has a depression or slot 41 and an aperture 43
formed therein. Friction retard pad support frame 39 is bolted by bolt means
(not shown) to base 17. Friction retard pad support 45 is mounted for sliding
motion in the space formed by slot 41 when it is attached to base 17. Attached
to the bottom of friction retard pad support 45 is friction retard pad 47.
Friction retard pad 47 is urged downward into contact with driven feed belt 5 byfriction retard pad spring 49, which is held in aperture 43 of friction retard pad
support 39 by shoulder 51.
In operation a stack of articles 3 is placed in input tray 1. Article
guide means 53 (see Figure 3) is positioned such that none of the articles can rest
above a centerline 55 of the normal force applicator roller drawn parallel to the
direction of feed of the articles. This encourages the articles to be drawn intothe rolling nip 28 formed between normal force applicator roller 27 and driven
feed belt 5. When it is desired to feed an article, the driven feed belt 5 is driven
by means (not shown) in the direction of travel of the fed articles as shown by
arrow 59 (see Figure 3). The movement of driven feed belt 5 in the direction
shown by the arrow 57 (see Figure 3) causes normal force applicator roller 27 toturn in the direction shown by arrow 61 ~see Pigure 3). Normal force applicator
spring 29 urges normal force applicator roller 27 downward against the top of the
articles present (usually two or three) in the rolling nip 28 formed by normal
force applicator roller 27 and driven feed belt 5. The normal force applicator
spring 29 is adjusted so that it will allow a few articles to be brought into nip 28
under the influence of a moving feed belt 5. The coefficient of friction betweendriven belt 5 and the bottom article of the stack of articles 3 and the rolling
motion of normal force applicator roller 27 causes two or more articles from thestack of articles 3 to be drawn into the rolling nip 28 formed between normal
force applicator roller 27 and driven feed belt 5. Since normal force applicatorroller 27 is pressed against only a few of the bottom articles in the stack of
articles 3, very little force is required to ensure feed of an article, even an
article whose leading edge may not lie flat. Similarly, since normal force
applicator roller 27 applies a force to only a few of the bottom articles in a
stack of articles 3, the top of the stack of articles 3 is unencumbered allowingthe addition of more articles to the stack of articles 3 even while the feeder is
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operating. The a~ticles in the stack of articles 3, which are moved into the
rolling nip 28 formed between normal force applicator roller 27 and driven feed
belt 5 by the movement of driven feed belt 5, are then brought into contact withfriction retard pad 47. The coefficient of friction between driven feed belt 5
5 and the bottom article of the stack of articles 3 is chosen to be higher than the
coefficient of friction between friction retard pad 47 and the same article so
that the article can be moved between the friction retard pad 47 and driven feedbelt 5 when driven feed belt 5 is operating. The friction retard pad 47 applies
sufficient force to block the feed of the article next above the bottom article
10 causing the friction retard pad 47 to act as an article separator.
Other types of separators may also be used with the present normal
force applicator concept. It has been found that the present normal force
applicator will operate reliably feeding ordinary sheets of paper or envelopes
with no adjustments being required. Also, typically only 100 to 150 grams of
15 force are required for a normal force applicator roller measuring about 1/4 inch
in diameter and about 3/8 inch in length.
Although specific embodiments and components have been described,
it will be understood by those skilled in the art that various changes in the form
and details may be made therein without departing from the spirit and scope of
20 the invention. All such changes in form and detail should be considered as
encompassed by the following claims.
