U.S. patent number 3,893,664 [Application Number 05/381,352] was granted by the patent office on 1975-07-08 for stock feeder for printing press.
Invention is credited to Elmer R. Thomsen.
United States Patent |
3,893,664 |
Thomsen |
July 8, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Stock feeder for printing press
Abstract
A stock feeder for an offset printing press has vacuum suckers
arranged below a stack of stock, like envelopes, with the suckers
being swung curvilinearly into and out of engagement with the
lowermost envelope in the stack in order to feed it from the stack
into the press. The suckers have an initial twisting motion after
they grip the lowermost envelope before lowering it from the stack,
and thereby separating it from the stack without disturbing the
next uppermost envelope. As the edge only of the envelope is
twisted downward and yet does not lower the body of the envelope,
two purposes are accomplished. First, the vacuum between the first
and second sheet is broken and second, the edge of the envelope has
been released from resting on the inwardly turned leaf springs. As
the suckers start their downward motion, a pressure roll swings
toward the envelope and contacts the envelope on the upper side
when the suckers have moved downward about three-fourths of their
travel and at which point the suction or vacuum from the vacuum
pump of the press is released. The pressure roller then continues
rearward toward the rubber feed roll until it clamps the envelope
against the feed roll so as to positively advance it into a set of
pull-out rolls and thence into the press.
Inventors: |
Thomsen; Elmer R. (Portland,
OR) |
Family
ID: |
23504684 |
Appl.
No.: |
05/381,352 |
Filed: |
July 20, 1973 |
Current U.S.
Class: |
271/100;
271/104 |
Current CPC
Class: |
B65H
3/0866 (20130101) |
Current International
Class: |
B65H
3/08 (20060101); B65H 003/08 () |
Field of
Search: |
;271/100,99,102,101,104,20,23 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Schacher; Richard A.
Assistant Examiner: Stoner, Jr.; Bruce H.
Attorney, Agent or Firm: Connors; Edward F.
Claims
What is claimed is:
1. A feeder for flexible sheet material comprising: a hopper means
for receiving and supporting a plurality of flexible sheets in a
stack; a vacuum gripping means movably disposed under said stack
and adapted to engage a marginal edge portion of the lowermost
sheet in the stack; means for initially moving said gripping means
in a twisting motion while it is engaged with the lowermost sheet
so as to twist the engaged sheet off of the stack and thereby
separate such sheet from the next uppermost sheet in the stack and
consequently break the vacuum between such sheets; means after
cessation of the operation of the foregoing means and consequent
completion of the twisting action for moving said gripping means
downwardly away from the stack with the sheet held thereby and thus
lowering the sheet from the stack; means for engaging the edge
portion of the next lowermost sheet in the stack and thus assisting
in the separation of the sheets and also retaining the stack
properly within the hopper means as the engaged sheet is lowered
from the stack; a conveying means to which the sheet is delivered
by the gripping means for conveying the sheet from the feeder;
means for returning the gripping means upwardly back into
engagement with the next lowermost sheet in the stack, said
gripping means including a sucker rod constituting a manifold and
having a plurality of suction cups constituting suckers mounted
therein in communication therewith; means connecting the sucker rod
to a vacuum source; said means for moving the gripping means
downwardly from the stack including a pair of arms mounted for
vertical swinging movement, and a rod supporting and actuating said
arms and said sucker rod being carried by the arms, said sucker rod
being rotatably journaled in the arms and said means for initially
moving the gripping means in a twisting motion including a
constraining linkage connected to the sucker rod and to a fixed
point so as to cause the sucker rod to rotate counterclockwise as
the arms first attempt to move it down away from the stack and
spring means connected to said arms to prevent the sucker rod from
lowering until the twisting action is completed and constituting
the means for returning the gripping means to its raised position
with the suction cups engaging the next lower most sheet in the
stack.
2. A feeder for flexible sheet material comprising; a hopper means
for receiving and supporting a plurality of flexible sheets in a
stack; a vacuum gripping means movably disposed under said stack
and adapted to engage a marginal edge portion of the lowermost
sheet in the stack; means for initially moving said gripping means
in a twisting motion while it is engaged with the lowermost sheet
so as to twist the engaged sheet off of the stack and thereby
separate such sheet from the next uppermost sheet in the stack and
consequently break the vacuum between such sheets; means after
cessation of the operation of the foregoing means and consequent
completion of the twisting action for moving said gripping means
downwardly away from the stack with the sheet held thereby and thus
lowering the sheet from the stack; means for engaging the edge
portion of the next lowermost sheet in the stack and thus assisting
in the separation of the sheets and also retaining the stack
properly within the hopper means as the engaged sheet is lowered
from the stack; a conveying means to which the sheet is delivered
by the gripping means for conveying the sheet from the feeder;
means for returning the gripping means upwardly back into
engagement with the next lowermost sheet in the stack, said
gripping means including a sucker rod constituting a manifold and
having a plurality of suction cups constituting suckers mounted
therein in communication therewith; means connecting the sucker rod
to a vacuum source; said means for moving the gripping means
downwardly from the stack including a pair of arms mounted for
vertical swinging movement and a rod supporting and actuating said
arms and said sucker rod being carried by the arms and including
means engaging the supporting rod for the arms of the gripping
means for adjusting the effective height of the gripping means
relative to the stack.
3. For use with a printing press having a vacuum means and having a
feed linkage, a feeder for feeding stock to the press comprising;
hopper means for supporting the stock in a stack; vacuum gripping
means movably disposed under said stack and having means connecting
it to the source of vacuum on the printing press with said gripping
means being adapted to engage a marginal edge portion of the
lowermost sheet of stock in the stock; means actuated by the
printing press feed linkage for moving said gripping means
downwardly away from the stack with the gripping means geing in
communication with the vacuum means on the press and with the sheet
held thereby so as to lower the sheet from the stack; means
responsive to said foregoing moving means for initially twisting
said gripping means in a revolving motion while it is engaged with
the lowermost sheet so as to twist the engaged sheet off of the
stack and thereby separate such sheet from the next uppermost sheet
in the stack and consequently break the vacuum between such sheets
prior to the downward movement of said gripping means which
downward movement is initiated and carried out only upon completion
of the initial twisting action; a conveying means to which the
sheet is delivered by the gripping means for conveying the sheet
from the feeder to the printing press, said conveying means being
actuated by the printing press in timed relation with the operation
of the press; means for moving the gripping means upwardly back
into engagement with the next lowermost sheet in the stack after
the removed sheet is delivered to the conveying means; said
conveying means including a feed roll driven by the press and onto
which the sheet is lowered by the gripping means and a pressure
roll adapted to clampingly hold the sheet against the feed roll and
means for moving said pressure roll into and out of clamping
relation with the feed roll in timed relation with the movement of
the gripping means; said last means including a rotatable rod,
means connecting the pressure roll to said rod in spaced parallel
and adjustable relation therewith, means actuated by the press
linkage for rotating the rod in one direction to hold the pressure
roll out of engagement with the feed roll and spring means
connected between a fixed point and the rotatable rod and operative
upon the deactivation of said foregoing means to swing the pressure
roll into clamping relation with the feed roll.
4. The invention of claim 3 wherein said means for moving said
gripping means downwardly away from the stack includes a rotating
rod having a bell crank, a reciprocating cam means driven by the
press feed linkage and adapted to engage the crank for rotating the
rod, a pair of arms carried by the rod and on which the gripping
means is mounted, said gripping means including a sucker rod having
a plurality of suckers, said sucker rod being rotatably journaled
in the arms and said means for initially moving said gripping means
in a twisting motion including a restraining linkage pivotally
connected between the rod and a fixed point, said linkage reacting
to the downward movement of the arms to effect an initial twisting
motion of the sucker rod.
5. The invention of claim 4 including means engaging the rod
carrying the arms for the sucker rod for raising and lowering the
effective height of the sucker rod in relation to the stack.
6. The invention of claim 4 wherein said reciprocating cam means is
provided with means for delaying the rise of the sucker rod which
means may be selectively employed in the instance of feeding longer
sheets so as to permit such sheets to be clear of the conveying
means before the spring means returns the sucker rod to its raised
position.
7. The invention of claim 3 wherein a reciprocating cam means is
driven by the press feed linkage, said conveying means including a
feed roll on which the removed sheet is placed by the gripping
means, a pressure roll, means mounting the pressure roll for bodily
movement relative to the feed roll, means connecting the pressure
roll to the cam means so it can be held thereby out of engagement
with the feed roll and spring means connected between a fixed point
and the mounting means for the pressure roll for moving it into
engagement of the feed roll after the removed sheet has been
delivered thereto by the gripping means, a rotatable rod having a
bell crank engaged by the cam means so as to rotate the rod, a pair
of arms carried by the rod and supporting the gripping means, said
arms being swung downwardly by the cam means to move the gripping
means downwardly and said twisting means including restraining
means pivotally connected between the gripping means and a fixed
point and reacting to the initial downward movement of the arms to
effect the initial twisting action of the gripping means and said
means for moving the gripping means upwardly back into engagement
with the stack including springs connected between the arms and a
fixed point, said springs also functioning to prevent the gripping
means from lowering until the twisting motion is concluded.
8. A feeder for flexible sheet material comprising; a hopper means
for receiving and supporting a plurality of flexible sheets in a
stack; a vacuum gripping means movably disposed under said stack
and adapted to engage a marginal edge portion of the lowermost
sheet in the stack; means for initially moving said gripping means
in a twisting motion while it is engaged with the lowermost sheet
so as to twist the engaged sheet off of the stack and thereby
separate such sheet from the next uppermost sheet in the stack and
consequently break the vacuum between such sheets; means after
cessation of the operation of the foregoing means and consequent
completion of the twisting action for moving said gripping means
downwardly away from the stack with the sheet held thereby and thus
lowering the sheet from the stack; means for engaging the edge
portion of the next lowermost sheet in the stack and thus assisting
in the separation of the sheets and also retaining the stack
properly within the hopper means as the engaged sheet is lowered
from the stack; a conveying means to which the sheet is delivered
by the gripping means for conveying the sheet from the feeder;
means for returning the gripping means upwardly back into
engagement with the next lowermost sheet in the stack; said
conveying means including a rotating feeed roll on which the sheet
is deposited by the gripping means, a pressure roll operable to
clamp the sheet against the feed roll, a pair of rotating pull-out
rolls into the nip of which the sheet is fed by the feed roll,
means operating in consort and timed relation with the means for
moving the gripping means for moving the pressure roll into and out
of sheet clamping relation with the feed roll, said last means
including spring means connected to the pressure roll for swinging
the pressure roll into sheet clamping relation with the feed roll,
said means for moving the gripping means downwardly including a cam
slide mechanism driven in a rectilinearly reciprocating path, said
pressure roll having a crank means, a roller carried by the crank
means and engaged by the cam slide mechanism to hold the pressure
roll away from the feed roll in opposition to the action of the
spring means until the gripping means has been moved to its
lowermost position with the removed sheet, said rod for the arms of
the gripping means having the arms pivotally connected thereto and
said rod having a crank end, a roller on the crank end engaged by
the cam slide mechanism which swings the arms downwardly while
maintaining the pressure roll in its position out of contact with
the feed roll until the gripping means delivers the removed sheet
to the feed roll.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally appertains to improvements in
apparatus for removing flexible sheets in consecutive order from a
stack and especially to new and novel improvements in apparatus for
feeding individual sheets from the bottom of a stack of such sheets
to a sheet handling machine.
The present invention relates to new and novel improvements in
feeders for feeding stock to an offset printing press or letter
press.
2. State of the Prior Art
Since the feeder of the present invention has been developed for
use with printing presses for feeding stock, like envelopes, to the
press such environment will be retained in relation to the
description of the background of the feeder.
In normal operation in feeding stock in the Multilith press, the
stock is placed in the feeder at the rear end of the press. The top
sheet is then lifted by suckers or vacuum cups and brought forward
into feed rolls and then fed to the printing cylinder by tapes. It
is obvious that the primary drawback of such feeding arrangement is
that it is necessary to stop the press in order to replenish the
stock, which is placed in the stock hopper of the feeder from the
top.
In view of this drawback, there have been many attempts to feed the
stock from the bottom of the stack by engaging the lowermost sheet
in the stack with a suction means and gripping the sheet to pull it
downwardly away from the stack.
One example of an apparatus for feeding individual sheets from the
bottom of a stack of such sheets to a sheet handling machine is
shown in U.S. Pat. No. 3,093,371, issued June 11, 1963. In such
patent, a suction means is disposed beneath the stack of sheets and
is swung curvilinearly into and out of engagement with the
lowermost sheet in the stack. In its initial engagement with the
lowermost sheet, the suction means grasps the sheet and draws the
latter straight downwardly as the suction means commences its
downward swinging movement away from the stack. A rod arrangement
cooperates with the suction means to move in and out of supporting
relation with the stack in consort with the engagement of the
lowermost sheet in the stack by the suction means. And in such
manner, an attempt is made to prevent the next uppermost sheet in
the stack from being pulled downwardly by the suction means as it
moves the lowermost sheet down away from the stack.
In U.S. Pat. No. 3,172,655, issued Mar. 9, 1965, a suction nozzle
is mounted for swinging movement on a horizontally transverse axis
below a stack of sheets and is moved upwardly to grip the lowermost
sheet. Cooperating with the suction nozzle in its downward swinging
movement away from the stack is a blank separator having a
laterally projecting tongue provided with an opening for
discharging an air jet. When the suction nozzle moves downwardly
carrying the engaged marginal edge portion of the lowermost sheet
away from the stack, the tongue moves inwardly between the engaged
sheet and the next uppermost sheet and discharges an air jet
between the sheet so as to prevent the next uppermost sheet from
being pulled downwardly by the suction nozzle.
In U.S. Pat. No. 3,071,369, issued Jan. 1, 1963, a suction cup is
disposed below a stack of flexible sheets and is actuated by a cam
means so as to be moved in a substantially direct up and down
movement toward and away from the stack. In such patent, there is a
rapid initial retracting movement of the suction cup due to a
bellows arrangement in cooperation with the cam means. Such is
intended to effect a quick jerking downward movement of the suction
cup and thereby realize an efficient removal of only one sheet from
the stack.
In U.S. Pat. No. 3,658,319, issued Apr. 25, 1972, an arrangement of
rocking side suckers and a central sucker is provided wherein the
central sucker operates to engage the lowermost sheet while, at the
same time, a blower nozzle forces air between the gripped sheet and
the next uppermost sheet to assist in forming a gap between the
engaged sheet and the next sheet thereabove. A separator tongue
then is swung into the gap between the engaged sheet and the next
sheet thereabove and the side suckers operate with a time delay
relative to the start of suction of the central sucker and engage
the engaged sheet to complete the downward pulling movement of the
sheet away from the stack.
In the various feeders, as disclosed in the above patents which are
exemplary of the prior art, the sheet that is engaged by the
suction means is pulled directly downwardly as the suction means
swings away from the stack or moves downwardly from the stack.
Whether the suction means swings curvilinearly or moves in a
substantially rectilinear path beneath the stack and regardless of
any mechanical means provided to operate in sonsort with the
downwardly moving suction means, there is still no reliable
arrangement provided whereby it can be assured that only one sheet
will be removed at a time. In all such patented devices, there
exists the possibility of two sheets being removed from the stack
at the same time. This is true even where there are attempts to
provide mechanical separators between the engaged sheet and the
next sheet or to provide air means for blowing between the sheets
so as to separate the sheet engaged by the suction means and the
next sheet thereabove in the stack.
None of the known bottom feeders operate with such degree of
reliability that the possibility of double feeding is obviated. And
yet, this malfunctioning is the most troublesome one, especially in
feeding stock to a printing press.
SUMMARY OF THE INVENTION
An important feature of the present invention resides in the
provision of a unique system of suckers in a sheet feeder mechanism
whereby the removal of one sheet at a time is positively ensured.
Thus, it is a primary object of the present invention to provide a
very novel and unique method and apparatus of sheet separation in a
feeder. In accordance with the present invention, the suckers
contact the lowermost sheet in a stack, but before they start a
downward motion in gripping the sheet and pulling the sheet away
from the stack, the gripped edge of the sheet is twisted downward
while at the same time, because of the twisting action, it is
pulled off leaf springs or the like which support or carry the
leading edge of the pile or stack.
It has been found in prior practice, regardless of various
mechanical arrangements such as disclosed in the aforesaid patents,
that double sheet feeding does occur. This is especially true in
feeding heavy stock, such as card stock, wherein the cards lie
close together and as the first card is pulled away it also pulls
the second card downwardly because of the vacuum action between the
first and second cards. Such dougle sheet feeding is overcome by
the present invention wherein the suckers in contacting the
lowermost sheet have a revolving motion before lowering. Because of
such revolving motion, the suckers twist the edge of the sheet and
thereby separate the edge of the engaged sheet from the next sheet
thereabove.
Because the sheet is merely twisted and then pulled downward off
the leaf spring carriers, heavy material such as card stock,
booklets, etc. can be fed.
If the stock had to be moved rearward and off a solid ledge, a
buckle in the sheet would have to occur. Stiff and heavy material
could not then be fed. In this invention the sheet does not buckle
and therefore very heavy material can be fed.
The suckers are in the form of suction cups provided on a hollow
manifold rod arranged transversely of the stack and rotatably
journaled at its ends in a pair of supporting arms, which are
pivoted on a parallel shaft that has one of its outer ends provided
with a bell crank having a cam roller which is engaged by a cam on
a reciprocating slide. The sucker manifold is retained in a raised
position by spring means and is moved downwardly, against the
urgement of the spring means, by the positive action of the cam in
engaging the roller and rotating the crank to cause the arms to
swing downwardly away from the stack. Prior to the downward
movement of the arms, the manifold rod is rotated. Thus, as the
suction cups contact the sheet, just before they start the downward
motion under the impetus of the supporting arms, the initial
downward movement of the arms is reacted to and resisted by the
restraining lever to cause the manifold to commence a rotary
counter-clockwise motion. The manifold is moved rearward while in
its rotating action to prevent the sheet from being pulled forward.
If the manifold merely rotated on its journals without moving
rearward, the sheet would then be pulled forward because the
suckers would be compelled to move forward. Because of the motion
of the manifold, the axis or joint of pivot is actually center of
the top of the suckers. Such rotary motion will cause the suction
cups engaging the leading edge of the engaged sheet to twist sudh
edge downwardly away from the next sheet thereabove.
The manifold or suction rod is connected by a flexible tube to the
conventional vacuum tube of the printing press which has a valve
means that controls the timing of the supply of vacuum to the
manifold rod. Such a press is well-known in the art; for example,
the A. B. Dick offset press manufactured by the A. B. Dick Co. of
Chicago, Illinois and the Chief 15 and Itek presses manufactured by
American Type Founders of Louisville, Kentucky.
The operation of the suckers is timed so that the vacuum sucks the
sheet at the high point of the suckers in relation to the stack and
is released just before the suckers are at the low point in regard
to their downward movement below the stack of sheets.
The cam carrying slide is mounted on the feeder frame alongside the
stock hopper for forward and rearward sliding movement under the
control of a feeder linkage from the printing press. Such slide
also carries another cam which is adapted to engage a roller
provided on the end of a bell crank for a pressure roll which
operates in coordinated relation with the suckers and in
cooperation with a feed roll. The feed roll is rotated through a
gearing in relation with the operating mechanism of the press so
that it is rotated in time relation therewith with the normal
pull-out rolls of the feeder.
The pressure roll is retained in a normally inoperative position
out of engagement with the sheet and away from its relation with
the feed roll by means of a cam which compels the pressure roll
forward and away from the feed roll. The pressure roll is returned
to the feed roll by means of a spring. As the cam moves forward,
the roller of the bell crank drops off the cam and permits the
pressure roller to move rearward by spring action to contact the
feed roll.
When the slide is in its rearward position, the sucker rod will
rise and the suckers will contact the lowermost sheet with the bell
crank being in high position. With the suckers at the high point,
they are in contact with the lowermost sheet. At this point, the
vacuum is engaged in the valve of the press and the slide is in its
most rearward position. As the slide is pulled forward by the lever
actuating mechanism from the press, the suckers carrying the sheet
are pulled downward toward the rubber feed roller. Before the
suckers move downwardly, they are rotated counter-clockwise so as
to twist the edge of the engaged sheet away from the stack and
thereby break the suction between the engaged sheet and the next
uppermost sheet. The suckers have a revolving motion before
lowering so as to separate the edge of the engaged sheet from the
next above sheet. Since the sheets are separated at the edge, the
vacuum which normally exists between the superimposed sheet is
broken and atmospheric air enters between the sheets.
As the suckers carrying the sheet are pulled downwardly by the
action of the arms being swung by the cam rod which is rotated
under the positive action of the engaged bell crank that is being
swung downwardly by the forwardly reciprocating cam slide, the
engaged sheet is moved down toward the feed roll. Before the sheet
contacts the feed roll, the pressure roll is moved, under the
spring urgement, into a position above the sheet and then, as the
sheet contacts the feed roll, the pressure roll squeezes the sheet
against the feed roll and causes the sheet to be impelled towards
the normal pull-out rolls. The suckers remain in a down position
because the cam slide is still in positive engagement with the
roller on the bell crank and holds them down until the sheet has
cleared.
When the sheet has traveled about seven inches, the pressure roll
then lifts off the sheet because the cam slide starts its rearward
action and engages the roller on the bell crank of the pressure
roll and cause the bell crank to be swung downwardly. At this same
time, the roller on the bell crank for the suction rod is free to
move upwardly under the spring urgement into a notched-out portion
in the cam slide provided in advance of the cam segment thereon
that is adapted to engage the bell crank roller. Thus, the suckers
are swung upwardly to contact the next sheet to be engaged.
Such coordinated movements of the suckers and the pressure roll are
effected by the cam slide which has cam segments that engage the
rollers on the bell cranks for each of the components, namely, the
sucker rod and the pressure roll.
Another important object of the present invention is to provide
means for retaining forward edge portions of the sheets in the
stack as the lowermost sheet is being separated therefrom.
Depending upon the nature of the sheet material, that is with
respect to its weight, softness or evenness, various mechanical
means may be provided and the provision thereof constitutes another
feature of the present invention.
Such means engages the leading edge of the stock being carried and
comprises the inwardly turned lower ends of leaf springs which are
vertically mounted at the front of the stock hopper and have their
lower inwardly turned ends disposed in the open space at the bottom
of the hopper through which open space the suckers are adapted to
move in engaging the front edge portion of the sheets in the
stack.
In another instance, needle screws are moved inwardly to contact
the leading edge of the lowermost sheet in the stack and such is
very helpful in running card stock especially.
In other instances, the springs may be used alone by backing out
the needle screw so that they do not contact the stock. And in
other circumstances, the springs may be put out of use by turning
them outwardly of the hopper so that they are not in vertical
position to have their lower ends engage the stock.
With some types of stock, both the springs and the needle screws
may be simultaneously used.
Another important object of the present invention is to provide
means for controlling the height of the suckers. The purpose of
this is that because of the type of stock, or paper or sheet
material or the condition thereof, it is desirable to lower or
raise the suckers for better contact with the sheet.
To realize such adjustment, an offset rod is journalled between the
walls of the hopper rearwardly and below the pivoted ends of the
supporting arms for the sucker tube. Such offset rod has eccentric
ends and the rod is pivoted to a threaded adjustment rod which is
attached to a cross bar between the sides of the hopper frame at
the rear thereof. By adjusting the threaded screw, the offset rod
is rotated which will, due to its eccentric journalling, raise and
lower it below the pivoted ends of the arms. Such ends are pivoted
to blocks fixed on the cam rod and the arms have cut-outs whereby
they can be bodily moved on their pivots relative to the anchoring
blocks to which they are pivoted and by means of which they are
attached to the actuating rod for effecting an upward and downward
swinging movement of the sucker rod.
Another important object of the present invention is to provide
means for delaying the rise of the suckers under the impetus of the
cam slide. This is especially useful depending upon the length of
the stock, as for example in feeding long envelopes.
The rise of the suckers is delayed by effecting a delay in the rise
in the bell crank and this is carried out by means of a pair of
cooperating levers which are adapted to be hooked together and
which are under spring urgement in being retained in their hooked
together relation but which can be spread apart as the cam slide
moves forwardly. One of the levers has a cam edge that is in
advance of the cam segment that is provided to contact the roller
on the bell crank for the sucker rod and, therefore, the initial
contact of such lever effects a delay in the real contact of the
cam slide with the roller on the bell crank, whereby the rise of
the sucker rod is delayed.
Another important object of the present invention is to provide a
simple, compact and very practical feeder mechanism for feeding
flexible sheet material in a true one by one fashion regardless of
the nature thereof and irrespective of the apparatus to which such
material is fed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the feeder of the present
invention.
FIG. 2 is a top plan view thereof.
FIG. 3 is a longitudinal vertical sectional view taken
substantially on line 3--3 of FIG. 2 and showing the suckers their
highest positions and in engagement with the lowermost sheet in the
stack.
FIG. 4 is a view similar to FIG. 3 showing the suckers on their way
down and the pressure roller in a position about to engage the
pulled down sheet.
FIG. 5 is a view similar to FIGS. 3 and 4 but showing the suckers
in their lowermost position and showing the pressure roll engaged
with the sheet and holding the sheet onto the feed roll with the
sheet being advanced by the feed roll to the pull-out rolls that
are driven by the press.
FIG. 6 is a side elevational view, similar to FIG. 1, but showing
the suckers in a down position and the pressure roll engaging the
sheet and holding the sheet on the feed roll.
FIG. 7 is an exploded perspective view of the suckers, the pressure
roll and the adjustment rod for varying the effective height of the
suckers.
FIG. 8 is a side elevational view, similar to FIGS. 1 and 6, and
showing the suckers beginning the downard stroke.
FIGS. 9, 10 and 11 are pictorial and somewhat diagrammatic views,
showing the action of the suckers in effecting a rearward twist of
the engaged sheet with the suckers effecting an initial rotating
action before they start their downward swinging movement away from
the stack so as to realize the rearward twist of the sheet and,
consequently, the effective separation of the engaged sheet from
the stack so as to break the vacuum existing between the engaged
sheet and the next uppermost sheet in the stack.
FIG. 12 is a fragmentary perspective showing of the restraining
leverage arrangement between the sucker rod which is rotatably
journalled in the outer ends of the pivoted supporting and
actuating arms and the frame of the feeder.
DESCRIPTION OF THE PREFERRED EMBODIMENT
For exemplary purposes, the sheet feeder 10 is shown in the
accompanying drawings in structural and operational association
with an offset printing press 12, such as one of the conventional
presses described in the foregoing. Since such press is
conventional and well-known in the art, the press is only
fragmentarily shown in FIG. 2. The frame 14 of the feeder 10 is
attached to the press by having its side plates 16 and 18 mounted
on the press frame in a position, as shown in FIG. 6. For this
purpose, the transversely spaced and parallel side plates 16 and 18
are provided with apertured mounting feet 20 that are adapted to be
anchored by bolts on the press frame.
The press 12 is provided with a feeder operating linkage 20a, as
shown in FIG. 6, and such feeder linkage, which is standard
equipment on the press, is adapted to actuate the operating
mechanism of the feeder 10, as will be described. The feeder 10 is
positioned at the feed or front end of the press and has its outlet
end 22 disposed above the conventional feed tapes 24 of the press
which tapes carrying the sheets fed from the feeder under the
conventional sheet riders and into the printing cylinders of the
press, as will be well appreciated by those skilled in the art.
The feeder 10 is provided with a bottom plate 26 that is mounted
between the side plates and which provides the bottom of a supply
hopper 28 within which the sheets of stock, such as the illustrated
envelopes 30, are disposed. The envelopes are piled in a stack
within the hopper and are fed from underneath the pile or stack in
one by one consecutive fashion. The hopper is composed of a front
plate 32 and a complementary upstanding rear plate 34. The rear
plate 34 is adjustable forwardly and rearwardly between the side
plates and by mounting adjustment means on the bottom plate 26.
The hopper further includes side plates 36 which are positioned
between the front and back plates 32 and 34, respectively, and
which can be moved apart or together so as to accommodate stock of
various widths. As shown in FIG. 2, the hopper side plates 36 are
slidably mounted in a slot 38 in the bottom plate 26 between the
frame plates 16 and 18 by virtue of slide blocks 40 that carry
thumb screws 42 for locking the plates in set positions along the
extent of the cross-bar 38.
As shown in FIGS. 3-5, the bottom plate 26 of the hopper 28
terminates rearwardly of the front plate 32 so that a feeding space
44 is provided. The front terminating edge 46 of the bottom plate
is inclined downwardly to provide a pull-off surface for the
envelopes to slide on as they are being pulled downwardly from the
stack.
A sucker rod 48, which is in the form of a hollow manifold, is
provided with suckers 50, which are in the form of vacuum cups, and
which are spaced along the extent of the sucker rod that is adapted
to be operatively movable within the feeding space 44. The sucker
rod is connected by a flexible tube 52 to the normal vacuum system
of the printing press 12, which, as will be understood by those
skilled in the art, has a valve means that is operated in time
relation with the movements of the sucker rod in relation to the
stack of envelopes.
As shown more particularly in FIG. 7 the sucker rod 48 has its end
portions 54 rotatably journaled in the forward ends 56 of operating
arms 58 which support the sucker rod and which move the same in a
curvilinear path of movement relative to the overhead stack of
envelopes. The arms 58 are provided with enlarged rear mounting
ends 60 that are pivoted by pivot pins 62 in clevises 64 which
integrally depend from blocks 66. The blocks 66 are sleeved onto an
actuating rod 68 and are held in fixed positions by set screws
70.
The actuating rod 68 is provided at one end with a bell crank 72
that has a cam roller 74 provided thereon. The bell crank 72 with
the cam roller 74 is disposed exteriorly of the side plate 18 and
is adapted to be engaged by a cam segment 76 provided on a slide
plate 78 that is slidably mounted on the outer face of the frame
side plate 18 for reciprocating backward and forward movement under
the actuation of the press linkage 20a, as shown in FIG. 6, for
example.
The end portion 54a of the sucker rod projects beyond the adjacent
mounting and supporting arm 58 and is fixed to a link 78a by a pin
79. The link 78a is pivoted to a link 80, as shown in FIGS. 7 and
12. The link 80 is attached by a pivot pin 82 to an anchoring
sleeve 84 which is fixed to the frame side plate 18 and projects
inwardly therefrom. The links 78a and 80 constitute a restraining
linkage which secures the sucker rod 48 to the frame in a manner so
as to effect the initial rearward revolving or rotating motion of
the sucker rod before the sucker rod is moved downwardly under the
actuation of the arms 58 in the manner as shown in FIGS. 3-5.
The downward swinging movement of the sucker rod is controlled by
the arms 58 under the action of the bell crank 72 and the cam
segment 76 of the slide plate 78. The operating and supporting arms
58 for the sucker rod are also provided with spring biasing means
which is in the form of coil springs 86 that are anchored to
depending lugs 88 on the rear end portion 60 of each of the arms 58
and to a cross bar 88a on the frame.
The end of coil springs 86a are fixed to depending pins 90 on a
cross rod 92 and to the frame bar 88a. The rod 92 is rotatably
journaled transversely between the side plates 16 and 18 of the
feeder frame and swingably supports a pressure roll 94. The
pressure roll 94 is provided at its ends with mounting sleeves 96
that receive threaded adjustment rods 98 which are positioned
through vertical openings in the rod 92 and are held in adjusted
fixed positions thereby by locking nuts 99. In this fashion, the
height of the pressure roll 94 can be adjusted. And more
particularly, the position of the pressure roll in relation to a
feed roll 100 can be controlled.
As shown in FIGS. 3-5, the feed roll 100, which is preferably
formed from rubber, is rotatably journaled between the side plates
16 and 18 of the feeder frame 14 and is positioned below and
slightly rearwardly of the feeding space 44 from the hopper 28. The
pressure roll 94 is adapted to cooperate therewith in holding a
sheet thereagainst after the sheet has been lowered from the stack
by the sucker rod 48. The feed roll is rotated in a
counterclockwise direction by a gearing 102 which also drives a
pair of pull-out rolls 104 in a counterclockwise direction and at
the same rate of rotation as the feed roll 100, as shown in FIGS.
3-5.
The pull-out rolls 104 are disposed in cooperating relation one
above the other and are adapted to receive therebetween the
pulled-off sheet which is given its initial forward impetus
relative to the nip between the pull-out rolls by the feed roll 100
with the pressure roll serving to hold the sheet onto the feed roll
so that it is frictionally engaged with and moved forward by the
feed roll 100 as can be appreciated from a consideration of FIG.
5.
The gear means 102 assures a proper rotation between the feed roll
100 and the pull-out rolls 104 which advance the sheet to the tapes
24 of the printing press. The gearing 102 is driven by gearing from
the printing press so as to assure the proper rotary speed between
the pull-out rolls and the sheet riders and printing cylinders of
the press with the sheets being fed onto the types and under the
sheet riders and then into the printing cylinders, as will be well
understood by those skilled in the art.
The pressure roll 94 is swung into a sheet clamping relation with
the feed roll 100 by the action of the spring means 86a and is
retained in a position away from the feed roll, as shown in FIG. 3,
by the action of the slide mechanism 78 which operates on a roller
106 that is provided on a bell crank 108 which is disposed
exteriorly of the frame plate 18 and which is connected by a pin
110 with one end of the pressure roll supporting rod 92. The center
gear in the gearing 102 between the gears for the pull-out rolls
104 and the feed roll 100 is rotatably journaled on one end of the
rod 92 internally at the inner face of the frame plate 16, as shown
in FIGS. 2 and 7.
Depending upon the particular type of stock, such as the nature of
the material, for example, the softness, unevenness, or the like,
various methods are provided for sheet separation and for
retention, in this regard, of the forward edges of the lowermost
envelope in the stack as the pulled out envelope is being lowered
from the stack by the suckers 50.
As best shown in FIGS. 3-5, the leading edge of the bottom envelope
30b in the stack after the preceding envelope 30a has been pulled
down from the stack by the suckers 50 is retained by various means.
Thus, spring bars 112, like flat clock springs, are vertically
oriented on the outside of the front wall 32 of the hopper means
and are held in vertical positions thereon by pins 114. The free
lower end portions project downwardly below the end of the front
wall and are inturned towards the stack so that the inturned end
portions 116 can engage and retain the leading edge of the
bottommost sheet 30b in the stack 30.
In some instances, additional retainers and separators will be
desired and, for this reason, needle screws 118 are adjustably
supported in threaded bores in a cross bar 120 fixed between the
frame plates 16 and 18 and are rotatable therein so that their
needle points 122 can be positioned beneath the leading edge of the
bottom envelope 30b in the stack 30, as shown in FIGS. 3-5.
The springs 112 and needle screws 118 may be conjointly employed
depending upon the nature of the stock. In such instance, the
springs will be left in the vertical positions, as shown in FIGS.
3-5, and the needle screws will be rotated until their inner
pointed ends 122 just touch the stock.
The spring bars 112 are disposed adjacent the ends of the front
plate and they may be put out of use by swinging them upwardly and
outwardly so that they will not be in operative positions. Then,
only the needle screws 118 will be used.
Accordingly, it can be seen that there are three means of sheet
separation for supporting the leading edge of the bottom sheet of
the stock. Such supporting means serves as means to help to
separate the sheets since it works in conjunction with the suckers
50 to hold the next succeeding sheet 30b in the stack as the
bottommost sheet 30a is being pulled therefrom by the downwardly
moving suckers 50.
Means is provided for adjusting the effective or working height of
the suckers 50. As shown in FIGS. 2, 3 and 7, an offset rod 124 is
provided with eccentric ends 126 which are rotatably journaled in
the frame side plates 16 and 18 with the offset rod underlying the
rear end portions 60 of the mounting arms. The end portions 60 are
provided with slots 128 that accommodate the supporting blocks 66
with the end portions 60 being free to be moved about the pivots 62
relative to the blocks 66 by virtue of the slots 128. Such movement
is effected by rotating the offset rod 124. For this purpose, an
adjustment rod 130 is pivotally attached, as at 131, to the offset
rod and the adjustment rod extends rearwardly and is provided with
a threaded end portion 132 that extends through a bore 134 in a bar
136 which is fixed between the frame side plates 16 and 18. A
knurled knob 138 is threaded onto the end portion 132 and bears
against the cross bar 136. The adjustment rod 130 has a fixed
collar 140 against which one end of a coil spring 142 coiled about
the rod bears with the other end of the spring bearing against the
cross bar 136. As can be appreciated, manual rotation of the knob
138 will cause the adjustment rod 130 to be moved axially
longitudinally of the feeder frame and will result in an effective
clockwise or counterclockwise rotary movement of the offset rod
124. By virtue of the eccentric mounting of such offset rod 124, it
will rise up against or move down from the end portions 60 of the
sucker rod supporting arms 58 and cause the arms to be moved up or
down in respect to their supporting blocks 66 on the supporting and
operating rod 68. This will cause the sucker rod to be moved to
higher or lower effective heights. Such action will be governed by
the type of stock or the condition thereof, for example. The
necessity to lower or raise the suckers 50 is dictated by the need
for better contact thereof with the sheets of stock in the
stack.
As shown in FIGS. 1, 6 and 8, the slide plate 78 is provided with
longitudinally extending slots 144 and 146 which form trackways
that slide on guide pins 148 and 150 that are fastened to the
exterior of the side plate 18 of the feeder frame. The slide plate
78 is provided with the cam segment 76 that engages the roller 74
of the crank lever 72 and which effects the downward swinging
movement of the arms 58 that produces the downward swinging action
of the sucker rod 48 that is shown in its downward movements in
detail in FIGS. 3-5. The slide plate also has a cam member 152 that
acts on the roller 106 for the bell crank 108 of the pressure roll
94.
For a better understanding of the operation of the feeder,
attention is first directed to FIGS. 1, 6 and 8 which show the
sequence of events in relation to the slide plate and the bell
cranks 72 and 108 for the sucker rod 48 and for the pressure roll
94.
With reference to FIG. 8, it will be noted that the slide plate 78
is starting forward and that the suckers 50 are in their upper
position and are beginning the downward stroke with the cam segment
76 engaging the upper roller 74 and causing the crank lever 72 to
be swung downwardly in a counterclockwise direction. Continuing to
FIG. 6, it can be seen that the sucker rod 48 is in its down
position and would be held in such position because the cam segment
76 is seated over the roller 74 on the bell crank 72 which would
hold the sucker rod 48 in a down position. In FIG. 1, the sucker
rod is shown in its uppermost position to which it has been urged
by the spring means 86 since the cam segment 76 has moved
rearwardly to permit the crank lever 72 to ride up to its uppermost
position.
The cam segment 152 has an upwardly and rearwardly inclined rear
edge 154 and a straight bottom edge 156. The bottom edge acts on
the roller 106 to hold the pressure roll 94 in its inoperative
position, as shown in FIG. 3. As the slide plate 78 moves forwardly
the roller 106 is allowed to travel up the inclined cam face 154
and this permits the springs 86a to be active to swing the pressure
roll into engagement with the feed roll 100, as shown in FIGS. 4
and 5.
When the slide plate 78 moves rearwardly the cam segment 152 will
act on the roller 106 to cause the pressure roll to be swung back
to its inoperative position, as shown in FIG. 3. And, as the slide
plate 78 moves rearwardly, the roller 74 for the bell crank 72 of
the sucker rod actuating mechanism will be allowed to move upwardly
under the action of the springs 86 and thus will allow the sucker
rod 48 to move to its uppermost position where the suckers 50 will
engage the underside of the front edge portion of the lowermost
envelope in the stack, as shown in FIG. 3.
Thus, when the slide plate 78 is in its forward position toward the
delivery end of the feeder 10, the suckers 50 are down and the
pressure roll 94 is against the rubber feed roll 100, as shown in
FIG. 5. As the slide plate 78 is reciprocated rearwardly by the
operating linkage 20a from the printing press, the suckers 50 will
rise and will contact the underside of the lowermost envelope 30a
in the stack, as shown in FIG. 3. With the suckers 50 in the high
position, they contact the underside of the front edge portion of
the envelope 30a. At this point, the vacuum is engaged in the
printing press valve and the slide plate 78 is in its most rearward
position.
As the slide plate is pulled forwardly on the guide pins 148 and
150 by the press operating linkage 20a, the cam segment 76 will
engage the roller 74 and, through the crank lever 72 and the rod 68
and the arms 58, will start the suckers 50 in their down position.
As the arms 58 start downwardly to swing the sucker rod 48 in the
downward curvilinear movement, the initial downward swinging action
of the arms 58 will result in a constraining or restraining action
on the sucker rod produced by the links 78 and 80 and this will
cause the sucker rod 48 to effect a rearward revolving motion. Such
rearward revolving motion will produce a twisting action and will
effect an initial twisting of the front edge of the envelope or
sheet 30a as shown in FIG. 10.
It must be understood that when the cam roll 74 is in the highest
position, the shaft 68 has rotated clockwise, causing the clevices
64 to arrive at their most forward position. In this position a gap
is created between block 66 and gap of arm 58. The suckers are now
in their most forward position. As the cam roll is forced down by
the cam 76, the clevices are rotated clockwise, pulling the arms 58
rearward until the gap closes.
The arms 58 and sucker rod are prevented from moving downward
because of the resistance of the spring 86. Clearing this action,
the sucker rod has moved rearward while the suckers have remained
in the original position except for having rotated 23.degree. in a
twisting motion. Then the gap having closed, the arms must move
downward because of the continuing rotary action of the rod 68 and
clevices 64.
The initial rotational motion of the sucker rod 48 will rotate or
twist the leading edge of the envelope 30a in such a fashion that
the edge will separate from the envelope 30b immediately above it
in the stack, as shown in FIGS. 3 and 10. The envelope 30a remains
otherwise in its original position without being pulled forward. As
the sucker rod 48 rotates and at the same time moves backward, the
normal vacuum between the envelopes 30a and 30b is broken and when
the sucker rod has moved back about a quarter of an inch, the
timing is such that the arms 58 will then start the downward motion
of the sucker rod 48, as shown in FIGS. 4 and 11.
As the sucker rod 48 moves downwardly to the position of FIG. 4,
the slide plate 78 has moved forwardly to the extent that the
roller 106 is now free to roll up the edge 154 so as to enable the
pressure roll 94, under the spring action 86A, to start moving
toward the feed roll 100, as shown in FIG. 4.
The extreme forward movement of the slide plate 78 will permit the
pressure roll 94 to move to its final position, as shown in FIG. 5,
wherein it will hold the envelope 30a against the feed roll l00.
The feed roll 100 will frictionally move the envelope 30a forwardly
to the nip between the pullout rolls 104 and the pull1out rolls
will grasp the sheet and feed it onto the pullout 24 and to the
printing press cylinders.
With regard to the slide plate 78 in its action on the roller 74 of
the sucker rod assembly, it is sometimes desirable to delay the
rise of the suckers 50. This may be desirable in the instance of
feeding long envelopes or long sheets of types of stock. To effect
such delay a slide arm 158 is disposed on the outer face of the
slide 78 and is mounted by slots 161 on pins 160 for horizontal
sliding movement. The arm has a front free end with a vertical cam
edge 162 that is disposed in advance of the cam segment 76, as
shown clearly in FIG. 8. A catch 164 is pivoted on a pin 166 above
the arm 158 and the catch and the arm have interlocking hook ends
168 and 170. A spring 172 is connected between the arm and the
catch and serves to urge the hook ends into interlocking
engagement, as shown in FIG. 8.
When the slide plate starts its forward movement, the cam edge 162
of the arm will first engage the roller 74 but this will not result
in a downward movement of the roller because the arm 158 will slide
rearward with the spring 172 giving way to the crank lever 70 and
permitting the ends 168 and 170 to break away and thus elongate the
arm. In this respect, the arm 158 will slide rearwardly since the
pins 160 are mounted in the slots in the arm, as shown in FIG. 8.
Thus, the arm can slide rearwardly to the position shown in FIG. 1
with the catch and the arm in the open position. When the slide
plate has moved to its rearward position, the spring 162 will be
active to cause the two parts to be interlocked again, as shown in
FIG. 6.
A locking lever 176 is pivoted as at 178 and is adapted to swing
down and to engage the spring retaining pin 174 on the arm for the
purpose of holding the arm in an open position, as shown in FIG. 1.
When held in such position, the catch and the arm will be in a
spread apart position, as shown in FIG. 1 and the arm will be
inactive. Thus, such mechanism can be rendered inactive when
running short envelopes or similar short stock.
In FIG. 1 of the drawings, the cam or slide plate 78 has moved
rearward to nearly its maximum, with the slide arm 158 in its most
forward position. With the slide arm in this position, the raise of
the suckers has been delayed so the longer sheet may clear before
the suckers raise. Now as the cam plate 78 moves rearward to its
extreme position, the roller 74 raises slightly higher and
therefore raises the arm and disengages the lock as shown in FIG.
2. In this position the suckers have raised to their highest
level.
Now as the cam plate 78 moves forward, the roller 74 contacts the
arm 158, holding it in this position as the cam plate moves. The
bevel of the cam on the cam plate contacts the roller, forcing it
downward and therefore lowering the sucker bar. When the roller 74
has reached its lowest point and having forced the arm 158
rearward, as shown in FIG. 1, the slide then moves forward by the
spring action to again lock in position with the catch 164. The arm
158 can move forward as its lower surface is slightly higher than
the surface of the slide or cam plate 74.
While the preferred embodiment of the present invention has been
illustrated in the accompanying drawings and described herein, it
can be appreciated that other means can be provided for effecting
the movement of the sucker rod and for realizing the coordinated
movements of the sucker rod and the pressure roll.
In this respect, while the invention has been described and
illustrated in connection with feeding envelopes to an offset
printing press, it is obvious that this is merely one environment
for the feeder. For the feeder can be utilized in other
environments where sheet material is fed to a sheet handling
machine, regardless of the nature of the material or the type and
nature of the machine or mechanism.
Thus, the foregoing description and the accomapanying drawings are
merely exemplary of one form of and one environment for the present
invention which is only limited by the scope and spirit of the
appended claims.
* * * * *