U.S. patent number 3,844,551 [Application Number 05/401,413] was granted by the patent office on 1974-10-29 for sheet shuttle feed.
This patent grant is currently assigned to Bell and Howell Company. Invention is credited to Wilbur J. Morrison.
United States Patent |
3,844,551 |
Morrison |
October 29, 1974 |
SHEET SHUTTLE FEED
Abstract
A vacuum-type sheet feeding device is described which comprises
a reciprocating shuttle plate having a gated vacuum groove. In
operation, as suction is applied to the groove and a sheet to be
fed is thereby sucked into the groove, the vacuum gate, which
closes off one end of the vacuum groove, yields to allow the sheet
to move into the groove. The sheet feeding apparatus also includes
a sheet magazine which comprises a separating ledge for supporting
a bottom front corner of a sheet stack, a sucker cup for pulling
the bottom sheet (the sheet to be fed) off of the separating ledge,
and adjustable lifters for supporting the rear corners of the stack
at different heights. In addition, the sheet feeding apparatus
includes a throat-knife mechanism which comprises a narrow throat
knife mounted on a pivoted throat-knife bracket. If the pivoted
throat-knife bracket is in an active position, the throat knife
protrudes downwardly in front of the shuttle-plate grove when the
shuttle plate is under a sheet stack, and adjacent to the
shuttle-plate groove when the shuttle plate is feeding.
Inventors: |
Morrison; Wilbur J. (Nazareth,
PA) |
Assignee: |
Bell and Howell Company
(Phillipsburg, NJ)
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Family
ID: |
26969710 |
Appl.
No.: |
05/401,413 |
Filed: |
September 27, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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296556 |
Oct 11, 1972 |
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Current U.S.
Class: |
271/99; 271/104;
271/106; 271/132; 271/165 |
Current CPC
Class: |
B65H
3/12 (20130101); B65H 3/0883 (20130101); B65H
3/085 (20130101); B65H 3/56 (20130101) |
Current International
Class: |
B65H
3/56 (20060101); B65H 3/08 (20060101); B65H
3/12 (20060101); B65h 003/08 () |
Field of
Search: |
;271/99,102,106,132,133,134,165,166,14,104 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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473,406 |
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Oct 1937 |
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GB |
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435,327 |
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Oct 1967 |
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CH |
|
Primary Examiner: Blunk; Evon C.
Assistant Examiner: Stoner, Jr.; Bruce H.
Attorney, Agent or Firm: Griffin, Branigan and Butler
Parent Case Text
This is a continuation-in-part application of U.S. Pat. application
Ser. No. 296,556, filed Oct. 11, 1972 now abandoned, and entitled
"Sheet Shuttle Feed."
Claims
The embodiments of the invention in which an exclusive property or
privilege are claimed are defined as follows:
1. A vacuum-type sheet feeding device for feeding the bottom sheet
from a stack of flat sheets, said device comprising:
a movable shuttle plate having a surface on which said stack rests,
for gripping said bottom sheet and pulling said bottom sheet out of
said sheet stack, said movable shuttle plate having motion in a
direction substantially parallel to the plane of said flat sheets,
said surface defining an elongated narrow groove therein which is
elongated in a direction parallel to said direction of said
shuttle-plate motion, and said narrow groove terminating at a back
end thereof so that said back end is closed off and said groove
extending to an edge of said shuttle plate at a front end thereof
so that said front end is open;
a gate mounted on said shuttle plate for closing off said groove
near said front end, but for yielding to allow said bottom sheet to
be sucked into said groove; and
a pneumatic-suction means for creating a pneumatic suction in said
groove to suck the bottom sheet into said groove;
wherein said bottom sheet which is sucked into said groove is
thereby adhered to said shuttle plate so that it moves with said
shuttle plate.
2. A vacuum-type sheet feeding device as claimed in claim 1 wherein
said gate comprises two independently swinging half gates.
3. A vacuum-type sheet feeding device as claimed in claim 1 wherein
is further included;
a magazine for holding said sheet stack said magazine including a
ledge for supporting one corner of said sheet stack; and
a separating means for disengaging the corner of the bottom sheet
of said sheet stack from said ledge.
4. A vacuum-type sheet feeding device as claimed in claim 3 wherein
said separating means comprises a reciprocating sucker cup which
pneumatically grips the bottom sheet of said sheet stack and pulls
said sheet off said ledge.
5. A vacuum-type sheet feeding device as claimed in claim 1 wherein
is further included:
a magazine for holding said sheet stack; and
adjustable lifters for providing supports for each of the rear
corners of said sheet stack and for allowing vertical adjustment of
said supports.
6. A vacuum-type sheet feeding device as claimed in claim 5
wherein:
said adjustable lifter comprise vertically oriented rods with said
supports positioned at the lower ends of said rods and with handles
located at the upper ends of said rods; and
said rods are clamp-knob mounted to a stationary frame.
7. A vacuum-type sheet feeding device as claimed in claim 5 wherein
is further included:
a magazine for holding said sheet stack, said magazine including a
ledge for supporting one corner of said sheet stack; and
a separating means for disengaging the corner of the bottom sheet
of said sheet stack from said ledge.
8. A vacuum-type sheet feeding device as claimed in claim 7 wherein
said separating means comprises a reciprocating sucker cup which
pneumatically grips the bottom sheet of said sheet stack and pulls
said sheet off said ledge.
9. A vacuum-type sheet feeding device as claimed in claim 1 wherein
a throat knife is positionable in front of said shuttle plate when
said shuttle plate is under said sheet stack so that as said
shuttle plate feeds said bottom sheet of said sheet stack, said
elongated narrow groove is immediately adjacent to said throat
knife and passes under said throat knife.
10. A vacuum-type sheet feeding device as claimed in claim 9
wherein said throat knife is elongated and an end tip thereof faces
said groove, with the width of said throat knife being less than
the width of said elongated narrow groove.
11. A vacuum-type sheet feeding device as claimed in claim 10
wherein said gate comprises two independently swinging half
gates.
12. A vacuum-type sheet feeding device as claimed in claim 10
wherein a mounting means is included for said throat knife which
allows selective movement of said throat knife to said active
position and out of said active position.
13. A vacuum-type sheet feeding device as claimed in claim 12
wherein is further included:
a magazine for holding said sheet stack, said magazine including a
ledge for supporting one corner of said sheet stack; and
a separating means for disengaging the corner of the bottom sheet
of said sheet stack from said ledge.
14. A vacuum-type sheet feeding device as claimed in claim 10
wherein is further included:
a magazine for holding said sheet stack, said magazine including a
ledge for supporting one corner of said sheet stack; and
a separating means for disengaging the corner of the bottom sheet
of said sheet stack from said ledge.
15. A vacuum-type sheet feeding device as claimed in claim 10
wherein said throat knife is positioned such that said throat-knife
end-tip protrudes into said elongated narrow groove when said
shuttle plate feeds said bottom sheet, and said gate has an
indentation formed at the top thereof to allow said gate to pass
beneath said throat knife.
Description
BACKGROUND OF THE INVENTION
This invention relates broadly to the art of sheet feeding devices
and more particularly to vacuum-type sheet feeding devices.
Some vacuum-type sheet feeding devices comprise reciprocating
shuttle plates positioned at the bottoms of sheet stacks. The cycle
of operation for these shuttle plates is normally as follows: A
suction is applied through the shuttle plate to the bottom sheet in
the sheet stack, thereby adhering the bottom sheet to the shuttle
plate. The shuttle plate then moves forwardly carrying the bottom
sheet with it and delivers this sheet to rollers or other gripping
means. At this point, the suction is turned off and the shuttle
plate returns to its position under the sheet stack.
In some such systems, knives or other blocking structures are used
to restrain other sheets in the sheet stack from moving with the
shuttle plate; and in some such systems the sheet stack rests on
one or more ledges from which the bottom sheet is pulled prior to
being fed forwardly by the shuttle plate.
One difficulty with some prior-art vacuum-type sheet feeding
devices is that suctions, or partial vacuums, applied by shuttle
plates, bleed through bottom sheets and cause second-from-bottom
sheets to adhere to the bottom sheets. When this happens, two
sheets are fed forwardly by the shuttle plates. Thus, it is an
object of this invention to provide a shuttle plate for a
vacuum-type sheet feeding device which substantially avoids this
bleed-through problem and thereby reduces the number of "double
feeds."
It is possible to reduce "double feeds" by reducing the amount of
suction applied to the bottom sheets; however, such a method also
reduces the strength with which the shuttle plate holds the bottom
sheet while moving it forwardly. Therefore, it is also an object of
this invention to provide a vacuum-type sheet feeding device which
reduces the possibility of a "double feed" but yet does not reduce
the strength with which the shuttle plate holds the bottom sheet
while feeding it.
In systems which employ blocking structures in front of shuttle
plates to prevent other sheets from following the bottom sheet
there is a difficulty in that the position of the blocking
structure is somewhat critical. That is, if it is too high, it may
allow the second from bottom sheet to follow the bottom sheet and
if it is too low it may prevent a thick bottom sheet from being
fed. This problem is magnified when very thin sheets are being fed.
Thus, it is an object of this invention to provide a
shutte-plate-sheet-feeding device which employs a throat knife the
position of which is not unduly critical.
With regard to feeding envelopes, it is sometimes difficult to
separate a bottom envelope, for some types of envelopes, by means
of a ledge and a pneumatic puller because the envelopes adjacent to
the bottom envelope tend to follow it off the ledge. This causes
double feeds. On the other hand, it is also sometimes difficult to
separate some other types of envelopes with a throat knife because
loose envelope edges and windows tend to catch on the knife. Thus,
it is an object of this invention to provide a vacuum-type sheet
feeding device which combines both types of sheet separating
mechanisms so as to retain their respective advantages while
reducing their disadvantages.
Yet another problem with some prior-art vacuum-type sheet feeding
devices is that they do not always function properly when sheet
stacks are warped. The reason for this is that if the sheet stacks
have warped shapes the bottom sheets may not make good contact with
the tops of the shuttle plates. Thus, it is yet another object of
this invention to provide a vacuum-type sheet feeding device which
can compensate for warped sheet stacks.
SUMMARY OF THE INVENTION
According to principles of this invention, a vacuum groove in the
top of a shuttle plate is closed at one end by means of a
vacuum-groove gate. However, the vacuum-groove gate allows sheets
to be pulled down into the groove when suction is applied within
the groove.
The vacuum-groove gate comprises two pivotable half gates biased
upwardly, toward the top of the shuttle plate. As a sheet is pulled
into the vacuum groove the half gates yield downwardly.
The above described shuttle plate is combined with a sheet-stack
magazine having a ledge for supporting a forward corner of a sheet
stack. When the bottom sheet of the sheet stack is to be fed, a
sucker cup moves downwardly pulling the bottom sheet off of the
ledge. At this point the shuttle plate feeds the bottom sheet
forwardly.
Further, the sheet feeding apparatus includes a throat-knife
mechanism which comprises a narrow throat knife mounted on a
pivotal throat-knife bracket. If the pivotal throat-knife bracket
is in an active position, the throat knife protrudes downwardly in
front of the shuttle plate when it is under a sheet stack, and
adjacent the shuttle-plate groove when the shuttle plate is
feeding. The throat knife can be pivoted to an inactive
position.
The magazine further includes two adjustable lifters, each being
located at respective rear corners of the sheet stack. When the
sheet stack is warped, one or both of the lifters can be raised or
lowered to thereby compensate for the warpage and cause the bottom
sheet of the sheet stack to make good contact with the top of the
shuttle plate. The adjustable lifters have handles extending
upwardly with which they can easily be gripped by an operator and
thereby raised or lowered. The adjustable lifters are clamped in
position by hand-tightened knobs once they are set in proper
positions.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features and advantages of the
invention will be apparent from the following more particular
description of a preferred embodiment of the invention, as
illustrated in the accompanying drawings in which reference
characters refer to the same parts throughout the different views.
The drawings are not necessarily to scale, emphasis instead being
placed upon illustrating the principles of the invention in a clear
manner.
FIG. 1 is an isometric view of a vacuum-type sheet feeding device
employing principles of this invention;
FIG. 2 is a front view of the device depicted in FIG. 1;
FIG. 3 is a side view of the device depicted in FIG. 1;
FIG. 4 is a secional view of the shuttle plate employed in the
device of FIG. 1 taken on line 4--4 of FIG. 1; and
FIG. 5 is a front view of portions of the device of FIG. 1;
FIG. 6 is a simplified isometric view of the shuttle plate of FIG.
1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, a vacuum-type sheet feeding device
comprises a sheet-stack magazine 10 which includes front guides 11
and 12, a separating ledge 14, side guides 15, a rear guide 17 and
adjustable lifters 16 and 18. The arrangement of the side and rear
guides 15 and 17 is somewhat simplified herein for the purposes of
clarity because they are not a significant part of this invention.
Also, an overall frame which interconnects the guides as well as
other elements of the device described herein are not depicted in
the drawings in order to more clearly depict the important features
of the invention.
A suction-separating apparatus includes a shuttle plate 19, having
a suction groove 20 therein, and a sucker cup 22.
As can be seen in FIGS. 1, 2 and 3, the magazine holds a sheet
stack 24. In this regard, the left-hand forward corner of the sheet
stack 24 is supported by the separating ledge 14, the rear right
and left-hand corners of the sheet stack 24 are supported by hooks
25 of the adjustable lifters 16 and 18, and the forward center
portion of the sheet stack 24 is supported by the top surface of
the shuttle plate 19.
The front guides 11 and 12 are positioned in front of the sheet
stack 24, the side guides 15 are positioned at the sides of the
sheet stack 24, and the rear guide 17 is positioned at the rear of
the sheet stack 24 between the adjustable lifters 16 and 18 and the
rear of the sheet stack. Thus, the sheet stack is guided on all
sides.
It should be noted that the top surface of the shuttle plate 19 is
positioned below the bottom end of the forward guide 12 by a
distance a.
The top surface of separating ledge 14 is even with the top surface
of shuttle plate 19.
With reference to FIGS. 4 and 5, the suction groove 20 of the
shuttle plate 19 is tapered upwardly to the top surface of the
shuttle plate 19 at the right-hand end thereof (FIG. 4) and extends
to the edge of the shuttle plate at the left-hand end thereof. The
suction groove 20 has a perforate false bottom 26 which encloses a
suction distributing space 28. The suction distributing space 28
communicates with a suction source (not shown) via a suction groove
line 30 and a suction groove valve 32.
The left-hand end of the suction groove (FIG. 4), which extends to
the edge of the suction plate 19, is covered by a suction groove
gate 34 which comprises two pivotable half-gates 36. The pivotable
half-gates 36 are pivotally attached to the forward end of the
shuttle plate by pins 38 (FIG. 5). The pivotable half-gates 36 are
biased upwardly by cantilevered piano-wire springs 40 (FIGS. 4 and
5) which also serve as stops to limit the upward travel of the half
gates. Tapers 41 on the tops of the half-gates 36 permit sufficient
clearance to allow the two half-gates 36 to swing freely downward
around the pins 38.
The shuttle plate 19 has forwardly and rearwardly reciprocating
movement as shown by an arrow 42 (FIGS. 1 and 3). The sucker cup 22
has up and down reciprocating movement as indicated by an arrow 44
in FIGS. 1 and 3.
The sucker cup 22 is connected via a sucker cup valve 46 (FIG. 2)
to a suction source (not shown).
It can be seen in FIGS. 1 and 3 that the adjustable lifters 16 and
18 are vertically adjustable with respect to each other and frame
members 45 so that the rear left and right-hand corners of the
sheet stack 24 can be set at different height levels. In this
regard, the adjustable lifters 16 and 18 are vertically movable in
vertical bores in frame members 45 and may be clamped in position
on the frame members 45 with hand-tightened knobs 47 (FIG. 3)
having a threaded shaft 48, once the lifters have been positioned.
The threaded shafts 48 screw into the frame members 45 and extend
through to the frame-member bores. It should also be noted that the
adjustable lifters 16 and 18 have handles which extend upwardly
thereby enabling an operator to easily lift or lower the adjustors.
In addition, the lifters can also be positioned laterally so that
they can be placed in an appropriate lateral position for various
widths. In this regard, the frame members 45 are mounted for
individual lateral movement on a slotted beam 51, for example.
FIG. 6 depicts the upper surface of the shuttle plate 19 on which
are formed saw-toothed frictional elements 49. These elements are
exaggerated in FIG. 6 for purpose of illustration. The frictional
elements 49 enhance the grip with which the shuttle plate 19 grips
sheets.
A throat-knife mechanism 50 includes a protruding throat knife 52,
a throat-knife bracket 54, a throat-knife-bracket pivot member 56,
and a clamping screw 58. It should be noted that the throat-knife
bracket 54 has a slot 60 therein which registers with the clamping
screw 58. The clamping screw 58 screws into the front guide 11 so
that its head 62 can be made to clamp the throat-knife bracket 54
to the front guide 11. The throat knife 52 is attached to the
throat-knife bracket and can, therefore, be rotated to an active
position as depicted in solid lines in FIGS. 1, 2 and 5 or to an
inactive position as depicted in dashed lines in FIG. 1. The tapers
41 on the tops of the half-gates 36 form an indentation at the tops
of the half-gates 36 which allows the throat knife 52 to be set
below the top surface of the shuttle plate 19 (the paper rest
level). Otherwise, the throat knife 52 could not very well be
placed below the half gates 36 because it would hit them on a
return stroke of the shuttle plate 19. In the preferred embodiment,
the throat knife 52 is no wider than the suction groove 20.
In operation, when a bottom sheet 64 of the sheet stack 24 is to be
separated from the stack, the sucker cup 22 moves upwardly and the
sucker-cup valve 46 opens; thus, the sucker cup 22 grips the
left-hand front corner of the bottom sheet 64 of the stack 24. At
this point, the sucker cup 22 moves downwardly carrying this corner
of the bottom sheet 50 with it. Thus, the bottom sheet 64 is pulled
off the ledge 14. Next, the sucker cup valve 46 closes so that the
sucker cup 22 releases the bottom sheet 64. This procedure provides
a first separation between the bottom sheet 64 and the
next-to-the-bottom sheet 66.
Simultaneously therewith, the suction groove valve 32 opens thereby
causing suction in the suction distributing space 28 of the suction
groove 20. This suction is distributed throughout the suction
groove 20 as shown in FIG. 5. As the bottom sheet 64 enters the
suction groove 20 the pivotal half gates 36 yield downwardly. The
suction groove 20 is deep relative to its width. It is difficult
for the next-to-bottom sheet 66 to follow the bottom sheet 64 into
the suction groove 20 under the influence of bleed-through vacuum
because the narrowness of the groove makes the beam strength of the
paper across this gap higher than if the groover were wider.
Therefore, the bottom sheet 64 is tightly gripped by the shuttle
plate 19, but the next-to-bottom sheet 66 is not. Thus, a second
separation between these two sheets is accomplished.
At this point, the shuttle plate 19 moves forwardly carrying the
bottom sheet 64 with it. The frictional elements 49 aid the shuttle
plate 19 in gripping the bottom sheet 64 as it moves forwardly. As
the shuttle plate moves forwardly carrying the bottom sheet 64
which is pulled down into the suction groove 20, the throat knife
52, when it is in the active (solid line) position, blocks the
movement of sheets trying to follow the bottom sheet 64. Thus,
still a third method of separation is provided. Eventually, the
bottom sheet 64 is transferred to a gripping mechanism and the
suction groove valve 32 closes thereby causing the shuttle plate to
release its grip on the bottom sheet 50. The shuttle plate then
returns to its position under the sheet stack 24 and the cycle is
repeated.
Should warpage of the sheet stack 24 be such that it is difficult
for the shuttle plate 19 to grip the bottom sheet, the shape of the
sheet stack can be adequately adjusted by lifting or lowering one
or both of the adjustable lifters 16 and 18.
It should be appreciated by those skilled in the art that the
yieldable suction-groove gate 34, including the pivotable half
gates 36, seal off the end of the suction groove 20, so that
adequate suction reaches the bottom sheet 64, but yet allows the
bottom sheet to be pulled down into the groove. At the same time,
the deep, narrow suction groove 20, although applying great suction
force to a bottom sheet, makes it difficult for a next-to-bottom
sheet to follow the bottom sheet into the groove. In this regard,
when the bottom sheet is pulled into the groove, a space or passage
opens up between the bottom sheet and the next-to-bottom sheet
which allows atmospheric air to rush in and neutralize any vacuum
bleed between these two sheets.
In addition, the vacuum groove is deep so that depression of a
sheet into this groove by suction forms a detent between the sheet
and the groove which provides better than average traction for
moving the sheet from beneath a sheet stack.
It should also be appreciated that this device provides three means
of separating the bottom sheet from the next-to-bottom sheet so
that the chance of having double feeds is reduced. In this regard,
with some types of envelopes, envelopes tend to follow the bottom
envelope off the separating ledge 14; however, the suction groove
20 and the throat knife 52 provide backup mechanisms by separating
such following envelopes from the bottom envelope when it is fed by
the shuttle plate 19.
It should also be noted that when envelopes have loose seams or
windows which tend to catch the throat knife 52 the throat knife
can be moved to an inactive position as shown in dashed lines in
FIG. 1. In this respect, however, with reference to FIG. 5, when
the bottom sheet 64 is pulled down into the groove 20, a relatively
large space separates the throat knife 52 from the bottom sheet 64.
Because of this, windows and loose seams do not catch on the throat
knife 52 as often as is the case for most blocking-structure-type
sheet separators. This feature also makes the vertical position of
the throat knife less critical since a separating slot must not be
one sheet width wide. Also, this feature allows the throat knife 52
to be set below the paper-rest level so that it more effectively
blocks sheets not sucked into the groove. Further, in this
connection, because the throat knife 52 is no wider than the
suction groove 20 (and is preferrably somewhat narrower) it does
not contact arched portions of the bottom envelope 64 which flare
up on each side of the groove. Further, the narrow throat knife
does not block the bottom envelope in areas where it is not
controllably pulled down into the suction groove.
It can be appreciated by those skilled in the art, that the
vacuum-type sheet feeding device disclosed herein is more efficient
than many prior-art sheet feeding devices.
While this invention has been particularly shown and described with
reference to a preferred embodiment, it will be understood by those
skilled in the art that various changes in form and detail may be
made therein without departing from the spirit and scope of the
invention. For example, various arrangements of valves could be
used with this invention. In addition, various magazine structures
could also be employed.
* * * * *