Note: Descriptions are shown in the official language in which they were submitted.
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Sheet transfer cylinders having movable suction heads to
engage the trailing edge of a sheet are commonly used in rotary
printing machines which can make a change to multi-color from
perfector printing. Such printing machines are generally des-
ignated as perfector printing machines and consist of two
print units and a sheet transfer arrangement which is situated
between the printing units with at least one sheet transfer
cylinder having movable suction heads. Movement of the suction
heads is commonly used for two primary purposes: first, to
provide means for adjusting for differing length sheets; and
secondl% to provide a reciprocating movement during rotation of
the cylinder to stretch and smooth the sheet being transferred.
As is known, the reciprocating movement of the suction heads is
of extreme importance in perfector printing for the sheet is
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`~ gripped at the trailing edge by the subsequent transfer cylinder.
Movement of the suction heads for sheet sizing during
, both multi-color and perfector printing have been accomplished
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heretofor in a variety of fashions such as independent gearing
arrange~ents and/or a number of internal adjustments. An
example of the latter method is seen in U. S. Patent 2,757,610
wherein internal positioning means securing each pair of suction
heads to the cylinder drive shaft were released and then re-
secured after rotating the suction heads to the new position.
These prior arrangement suffered from a variety of draw backs,
for example; cost, complexity, maintenance, and lack of efficiency.
By means of the present invention which includes a hollow
shaft for driving the sheet transfer cylinder and a control
shaft disposed co-axially therewithin, externally accessible
means are provided for simultaneously moving all suction heads
for sheet sizing thereby overcoming or, in the very least greatly
alleviating the deficiencies of the prior adjusting arrangements
mentioned hereinabove.
Accordingly, it is one primary object of the invention
herein to provide a superior externally accessible arrangement
to facilitate movement of the suction heads for sheet sizing.
Sheet transfer cylinders, particularly for use in perfec-
tor printing, are advantageously provided with a means to imparta reciprocating movement to the suction heads during rotation of
the cylinder to stretch and smooth the sheet being tranferred.
Such arrangements heretofor have generally been approached on
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the basis of either guiding the suction heads on a tangent to
the periphery of the transfer cylinder, for example as-
illustrated in U. S. Patent No. 3,096,088 or on the basis of
pivotably mounting the suction heads in the area between the
periphery of the cylinder and the axis of the sheet transfer
cylinder about an axis parallel to the axis of the transfer
cylinder, such as is illustrated U. S. Patent No. 3,430,946.
The reciprocating movement of each suctinn head is made
with the first mentioned species by means of the vacuu~ developed
in the suction head after it contacts the sheet and by a return
spring which opposes this vacuum. These suction heads not only
hold the trailing edge of the sheet on the transfer cylinder,
but also stretch and smooth the sheet when it is delivered in a
~rinkled condition. When pulling and stretching the sheet on
the outer surface of the transfer cylinder, it is important that
all suction heads move away from all related grippers at the same
time and that they travel the same distance for evenly stretching
the entire sheet on the transfer cylinder. Small deviations
in the resiliency or spring characteristics of the inner return
springs in the suction heads can cause one or more of the suction
heads to move sooner than the other suction heads and/or can
cause the suction heads to move different distances opposite to
` the grippers. The result of both is that the sheet may be
unevenly pulled over the periphery of the cylinder. Also,by
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using the same vacuum source for creating the suction for the
suction heads and for causing the reciprocating movement,
certain disadvantages are unavoidable. For example, with
especially thin papers, such as tissue, the vacuum required for
the movement of the suction heads can be so great that the suction
on the tissue which is in contact with the suction head may be
excessive thereby causing d~mage to the tissue paper.
For these reasons, the second species was developed where
the sheet transfer cylinder is divided into individual sheet
support discs, and the suction heads are arranged between these
discs. The suction heads are mounted on a common pivot shaft
arranged in the sheet transfer cylinder and there is an auto-
matic pivot mechanism provided for the pivotable rotation of the
common shaft. Further, a special valving mechanism provides
vacuum and air to the suctian heads. These mechanisms are quite
expensive and space consuming. Furthermore, with transfer cylind-
ers that have several gripper units and therefore, several suction
head units, all this must be separately provided for each suction
head units.
With both species of sheet transfer cylinders discussed
above the suction heads are not moved precisely along the
cylinder periphery but are more or less approaching it. This is
true for the both the straight line guidance of the suction heads
as disclosed in U. S. Patent No.3,096,088 and for the pivotable
suction heads that pivot about an axis that is parallel
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to and between the suction heads and the cylinder axis as dis-
closed in U. S. Patent No. 3,430,096. Accordingly, the sheet
does not lie smoothly on the transfer cylinder in the area of
the suction heads and, therefore, cannot be completely stretched
and smoothed when transferred to the next following cylinder as
is desirable with perfector printing.
By means of the present invention which includes a sheet
transfer cylinder having suction heads carried to pivot about
the longitudinal axis of the transfer cylinder, the hereinabove
mentioned problems of reciprocating suction heads for sheet
tensioning are overcome or, in the very least, greatly eleviated.
With the arrangement of this invention, the suction heads are
moved through an arc which coincides precisely with the peripher-
ary of the sheet transfer cylinder. This eliminates all the
descri~ed disadvantages caused by the paths of movement of the
prior art suction heads when they deviate from the cylindrical
surface.
Accordingly, it is a further primary object of the inven-
tion herein to provide an improved sheet transfer cylinder which
includes heads thereon which are reciprocable for sheet tensioning
through an arc which coincides precisely with the peripherary
of the sheet transfer cylinder.
The invention herein utilizes a cam-cam roller arrangement
in providing the reciprocal movement of the suction heads for
sheet tensioning. The cam-cam roller cooperation is adjustable
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by externally accessible means. Accordingly, the amount of
reciprocal movement is readily selectively adju~table. Further-
more, when running in the multi-color printing mode it is often
the case that the reciprocal movement of the suction head is
not desired. In these latter instances, the externally accessible
means provide an efficient arrangement for disengaging the cam-
cam roller cooperation. Accordingly, it is still a further object
of this invention to provide a readily accessible means for
adjusting the amount of reciprocation of the suction heads for
sheet tensioning.
These and other objects and advantages of the present
invention will become more readily apparent upon a reading of the
following description and drawings in which:
Fig. 1 is a longitudinal cross-sectional view of a sheet
transfer cylinder constructed in accordance with the principles
of the present invention having two gripper units (one shown)
and two suction heads (one shown) for a perfector printing
machine;
Fig. 2 is a developed cross-sectional view of a portion
of the mechanism for controlling the pivotable movement of the
of the suction devices of the sheet transfer cylinder illustrated
in Fig. 1;
Fig. 3 is a schematic end view of the sheet transfer
cylinder taken through the direction of the Arrow A in Fig. 1
illustrating the position of the adjustments elements of the suction
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devices in perfector printing for the shortest sheet length;
Fig. 4 is a cross-sectinnal view, partially schematic,
of the sheet transfer cylinder taken along line B-B of Fig. 1,
illustrating the position of the suction devices on the sheet
transfer cylinder in perfector printing for the shortest sheet
length:
Fig. S is a schematic end view of the sheet transfer
cylinder taken in the direction of Arrow A in Fig. 1, illustra-
ting the adjustment to the suction devices in perfector printing
for greatest sheet length;
Fig. 6 is a cross-sectional view, partially schematic,
of the sheet transfer cylinder taken along line B-B of ~ig. 1,
illustrating the position of the suction devices on the sheet
transfer cylinder in perfector printing for greatest sheet length;
< 15 Fig. 7 is a schematic end view of the sheet transfer
cylinder taken in the direction of Arrow A in Fig. 1, illu~trating
the adjustment to the suction devices in multi-color printing for
the shortest sheet length;
Fig. 8 is a cross sectional view, partially schematic, of
~ 20 the sheet transfer cylinder taken along line B-B of Fig. 1,
! illustration the position of the suction devices in multi-color printing for the shortest sheet length;
Figs. 9 and 10 are views similar to Figs. 7 and 8, respect-
ively, illustrating the adjustment and the position of the suction
devices in multi-color printing for the greatest sheet length; and
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Fig. 11 is a schematic plan view, partially in section,
of the sheet transfer arrangement of the present invention
disposed between two print works.
As best illustrated in Fig. 1, a sheet transfer cylinder
10 of the present invention comprises: an elongated hollow
cylindrical power shaft 12 which is rotatably mounted by respective
end bearings 13 and 14 in lateral frames 15 of a suitable
machine frame; a plurality of sheet support discs 11 which are
longitudinally spaced along the shaft 12, coaxial therewith
and supported thereby adjacent respective outer peripherial
portions of shaft 12; a plurality of spaced suction segments 16
coaxially received with respect to shaft 12 longitudinally
intermediate adjacent pairs of discs 11; and an elongated
cylindrical control shaft 32 which is coaxially received within
hollow shaft 12 and rotatable with respect thereto.
. The suction segments 16 and 16a ~16a being used to identify
the longitudinal end suction segments) are suitably rotatably
supported with respect to shaft 12, such as by bearings 17:
Each suction segment 16 and 16a supports a suitable suction
head 18 (one of which is shown in Fig. 1) which are operable
in a known manner to support the tail end of a sheet during the
passage thereof around the sheet transfer cylinder 10. Suitable
means are provided to provide blow air or suction at suction
heads 18; for example, known air channels 19 and valves 20 are
provided in suction plates 21 of each suction segment 16 or 16a
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which may be rendered selectively operable to connect with a
suction air source, a blow air source or may be switched off.
In the latter instance the end suction segments 16a may be
switched off if desired when transfering relatively narrow sheet
widths.
Sheet transfer cylinder 10 additionally includes suitable
grippers 27 thereon which are operable in a known manner
to grip the head end of a sheet being transferred by transfer
cylinder 10. In the particular embodiment illustrated, grippers
27 are rendered operative in a known manner, for example through
the utilization of gripper actùating cams 22 and 23 which actuate
a cam roller 24, gripper crank 25 and gripper shat 26. Gripper
ca~ns 22 and 23 are suitably supported by bearing cover 28 and
are secured thereto by fastening means such as screws 29.
Control shaft 32 includes thereon longitudinally spaced
latch arms 33 which extend radially outwardly therefrom through
adjacent peripherial slots 34 to connect with respective end
suction segments 16a. Latch arms 33 are structured to move -
arcuately~ along slots 34 upon rotation of control shaft 32.
As shown, slots 34 extend over about 90 of the circumference
of shaft 12 to provide the required angular adjustment for the
desired sheet length as will be fully apparent from the following
description. Latch arms 33 are connected at the radially outward
ends thereof to respective suction segments 16a by rectangular
end portions 35 that are positioned in corresponding notches of
suction segments 16a.
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TheErimary drive train for sheet transfer cylinder 10
may be provided in any suitable manner, for example by a gear
36 which is secured by the screws 37 onto hollow shaft 12. Co-
axial with gear 36 is a further gear 38 releasably connected
thereto for driving the drive gear of the next following transfer
cylinder 39 (third transfer cylinder in Fig. 11). As illustrated
in Fig. 11, an impression cylinder 40 of the first print works
carries a drive gear 41. A first transfer cylinder 42 has a
drive gear 43. The middle transfer cylinder 10 has a drive gear
36 meshing with the gear 43 of the first transfer cylinder 42.
Gear 38 is coaxial with gear 36 of middle transfer cylinder 10
and meshes with gear 44 of transfer cylinder 39. A second - -
impression cylinder 45 with drive gear 46 meshed with gear 44
follows and thereafter, the following cylinder 47 of the seaond
print works has a drive gear 48 meshed with gear 46. Drive
gear 36 for sheet transfer cylinder 10 and gear 38 for the
following transfer cylinder 39 are connectable to each other in
different relative angular positions by index bolts 49, clamp
ring 50 and clamp screws 51 (one of which is shown). The
operation and specific structure of the driving arrangement
briefly discussed hereinaboue is known in the art and a detailed
description is not deemed necessary for an understanding of this
invention. For purposes of this description, the disclosure of
U. S. Patent No. 3,772,990 is incorporated herein for a more
complete description of the structure and operation of such a
driving arrangement.
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All suction segments 16 and 16a are firmly connected with
each other by an alongated suction tube 52 extending continuously
therebetween along an axis which is parallel to the longitudinal
axis of shaft 12 and radially outwardly spaced therefrom. Thus when
such segments 16a are rotated by means of rotation of control shaft
32, segments 16 are simultaneously rotated therewith an equal amount.
The inner space 53 of suction tube 52 is connected with a suction
or blow air conduit 56 through a suitable rotary spool valve having
rotary and stationary portions 54 and 55, respectively. A bear-
ing 57 is positioned radially intermediate valve portion 55 and the
adjacent peripherial portion of shaft 12. The suction tube 52
communicates with suction heads 18 via channels $9 and valves 20
of suction plates 21. It is to be noted that the structure and -
supporting arrangement of suction segments 16 and 16a will at all
times, during the rotative movement thereof, result in suction heads
18 being coincident with the adjacent outer periphery of transfer
cylinder 10 regardless of the particular orientation thereof with
respect to such periphery.
The mechanism for clockwise or counter-clockwise rotation of
control shaft 32 and suction heads 18 relative to the longitudinal
axis of shaft 12 is illustrated in Figs. 3, 5, 7 and 9. This
mechanism provides means for both rotation of shaft 32 for movement
of suction heads 18 for sheet sizing as well as means for providing
a predetermined acruately reciprocating movement of suction heads
18 for sheet tensioning prior to transfer. In instances of both
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rotation for sizing and arcuately reciprocating movement, the control
shaft 32 is rendered rotatable adjacent a readily accessible ex-
terior portion of sheet transfer cylinder 10.
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The mechanism includes an elongated lever 58 which is pivotably
carried at a longitudinally intermediate portion
thereof by cylindrical pin or axel 59 which extends outwardly
from external gear 38. One end of lever 58 supports a cam
follower or roller 60 which cooperates with a cam 61 and which is
suitably supported by a cam holder 62. The cam 61-cam roller 60
arrangement provides for the arcuately reciprocating movement
of suction heads 18. The other end of the lever 58 is articulatedly
linked through bolt 63 with rod 65. The rod 65 is biased by
compression spring 64 toward the cam surface of cams 61. Spring
64 is disposed around the rod 65 intermediate a stop 66 and
an enlarged free end of rod 65. The lever 58 is also pivotably
connected at the end thereof adjacent cam roller 60 to one end of
an intermediate connection arm or link 67 that at the opposite
end thereof is pivotably connected with a lever arm 68. The lever
arm 68 is releasably connected to a control lever arm 69 which
is securely fastened to control shaft 32. This releasable
connection is made by lock screw 70 which is positioned in a
peripherial slot 71 of control lever arm 69. Lock screw 70 may
be selectively released~f~ repositioning within peripherial slot
71 to adjustfor different angular positions of control arm 69
for sheet sizing. The relative position of lever arm 68 with
respect to the control lever arm 69 is indicated by a scale 72
on lever arm 69 and indicator 73 on lever 68.
The relationship of the cam 61-cam roller 60 for providing
the reciprocating movement of suction heads 18 for the tensioning
of the s}eet being transferred is controlled by an externally
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accessible screw 74. The location and adjustment of screw 74
cooperates within an eccentric 75 in such a manner that, as
illustrated in Figs. 3 and 5, the cam 61-cam roller 60 are
cooperable to ~rovide such reciprocating movement of suction
heads 18, and, as illustrated in Figs. 7 and 9, eccentric 75
engages link arm 67 to cause cam roller 60 to move radially
- inwardly a distance such that there will be no cooperation be-tween cam roller 60 and cam 61, and, hence, no reciprocating
movement of suction heads 18. Thus, the Figs.3 and 5 relationship
of the linkage structure illustrates an arrangement which pro-
vides for sheet tensioning during perfector printing and Figs.
7 and 9 illustrate such a relationship wherein the suction heads
18 will not reciprocate, such as may be desired during multi-
color printing. Furthermore, if desired, the eccentric 75 may
be suitably adjusted, by means of screw 74,to vary the amount of
reciprocation of suction heads 18 from the maximum amount, as
is illustrated in Figs. 3 and 5, to a lesser amount.
In Figs. 4, 6, 8 and 10, the sheet is represented on
sheet transfer cylinder 10 with a heavy line 76. The adjust-
ment of both print works to each other for the format sheet length
adjustment in perfector printing is made in a known manner;
;~ for exampl~ as described and illustrated in U. S. Patent 3,772,990.
This adjustment is shown by the position of indicator 77 affixed
to hollow shaft 12 relative to scale 78 which is affixed to gear
; 25 38.for each sheet length. When adjusting the machine for
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perfector printing for the shortest sheet length (Figs. 3 and
4) and also for the greatest sheet length (Figs. 5 and 6),
indicator 73 shows on scale 72 at maximum-plus. In perfector
printing the adjustment for format sheet length is as described
in U. S. Patent No. 3,772,990 and is shown between indicators
77 on scale 78. Hence, during perfector printing, indicators
77 on scale 78 is adjusted to minus (Fig. 3) for the smallest
format sheet length and for the greatest sheet length is adjusted
to plus.
For multi-color printing for the smallest format sheet
- length (Figs. 7 and 8), indicator 73 on scale 72 is set for
minus. For the greatest format sheet length (Figs. 9 and 10),
indicators 73 is set for plus. In setting and resetting in-
` dicators 73, lock screw 70 is loosened and control shaft 32 is
turned an appropriate amount -in the desired direction to change
the arcuate spacing of suction heads 18 with respect to the grippers
27. Generally in either the greatest or shortest format sheet
length in multi-color printing, indicator 77 on scale 78 is set
for plus. A format sheet length sheet adjustment for multi-
color printing is naturally not required when the suction heads
are used. The adjustment between indicators 73 and scale 72
accordingly brings about the format sheet length adjustment for
multi-color printing.
The invention herein is broadly directed to a sheet
transfer cylinder for a rotary printing machine having an
improved means for smoothing a sheet during perfector printing
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as well as for rapid change over from perfector printing to
multi-color printing and ad~usting to different length sheets.
Accordingly, it is understood that various modifications may be
made byone skilled in the art with respect to the embodiments
S described herein without departing from the scope of the
invention.
Having described an embodiment of the invention
as is presently preferred, it is understood that the scope of
the invetion herein is not restricted by such description and
that such scope is only defined by the claims set forth herein-
after.
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