U.S. patent application number 09/740636 was filed with the patent office on 2001-07-05 for device for aligning sheets laterally.
Invention is credited to Butterfass, Hans, Mohringer, Markus, Roper, Markus.
Application Number | 20010006274 09/740636 |
Document ID | / |
Family ID | 7933138 |
Filed Date | 2001-07-05 |
United States Patent
Application |
20010006274 |
Kind Code |
A1 |
Butterfass, Hans ; et
al. |
July 5, 2001 |
Device for aligning sheets laterally
Abstract
A device for aligning sheets laterally on a feed table of a
sheet-processing machine, having a side stop, includes a suction
pull nozzle movable transversely to a sheet transport direction and
being formed with a plurality of suction openings, the suction
openings being distributed so that the number of suction openings
arranged in the sheet transport direction becomes greater in a
transverse direction towards the side stop.
Inventors: |
Butterfass, Hans;
(Heidelberg, DE) ; Mohringer, Markus; (Mannheim,
DE) ; Roper, Markus; (Schriesheim, DE) |
Correspondence
Address: |
Lerner and Greenberg, P.A.
P.O. Box 2480
Hollywood
FL
33022-2480
US
|
Family ID: |
7933138 |
Appl. No.: |
09/740636 |
Filed: |
December 18, 2000 |
Current U.S.
Class: |
271/250 |
Current CPC
Class: |
B65H 2406/36 20130101;
B65H 9/105 20130101 |
Class at
Publication: |
271/250 |
International
Class: |
B65H 009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 1999 |
DE |
199 61 048.7 |
Claims
We claim:
1. A device for aligning sheets laterally on a feed table of a
sheet-processing machine, having a side stop, comprising a suction
pull nozzle movable transversely to a sheet transport direction and
being formed with a plurality of suction openings, said suction
openings being distributed so that the number of suction openings
arranged in said sheet transport direction becomes greater in a
transverse direction towards the side stop.
2. The aligning device according to claim 1, wherein said suction
openings are formed as suction bores.
3. The aligning device according to claim 2, wherein said suction
bores have greater diameters in said direction towards the side
stop than towards a center of the feed table.
4. The aligning device according to claim 2, wherein said suction
openings are distributed in the form of a triangle.
5. The aligning device according to claim 2, wherein said suction
openings are distributed in the form of a semicircle.
6. The aligning device according to claim 1, including a suction
chamber for supplying vacuum to said suction bores, said suction
chamber being divided into two subchambers in said transverse
direction, said suction chamber being constructed so as to be
disconnectable.
7. The aligning device according to claim 1, including a slide
operatable in an infinitely variable manner in said transverse
direction for closing said suction bores.
8. A device for aligning sheets laterally on a feed table of a
sheet-processing machine, having a suction pull nozzle movable
transversely to a sheet transport direction and having a plurality
of suction openings, comprising a side stop formed with a slope
extending in a direction of a sheet lateral edge.
9. The aligning device according to claim 8, wherein an imaginary
extension of said slope forms an acute angle with a transport plane
of said feed table.
10. A device for aligning sheets laterally on a feed table of a
sheet-processing machine, having a side stop and a suction pull
nozzle movable transversely to a sheet transport direction, and
being formed with a plurality of suction openings, comprising a
run-on slope formed on the side stop, said run-on slope being
oriented counter to the sheet transport direction.
11. The aligning device according to claim 10, wherein said run-on
slope forms an acute angle with a sheet guide plane.
12. The aligning device according to claim 10, wherein said run-on
slope is constructed so as to extend below a sheet guide plane.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a device for aligning sheets
laterally, in particular, in the feeder of a sheet-processing
machine.
[0003] In order to feed a sheet with proper alignment to a
sheet-processing machine, for example, a printing machine, it is
necessary to align the sheet in the circumferential direction at
so-called front guides or lays and to align it laterally at
so-called side stops. For this purpose, the sheet is conveyed
against the front guides by a suitable transporter, and is drawn
against the side stops by a so-called side pulling device.
[0004] The German Patent 972 459, for example, discloses the use of
a suction pull rail, which sucks the sheet from below by a suction
nozzle and conveys the sheet against a side stop. To prevent the
sheet from escaping upwardly when it impacts the side stop, a
hold-down plate is provided in order to hold the sheet down on the
feed table.
[0005] Such hold-down plates, however, have the disadvantage that a
sheet which is aligned in the leading region thereof as it is
conveyed into the sheet-processing machine must also be conveyed
through, under the down-holder at the trailing end thereof.
Extremely small skewed sheet positions or skewed sections lead to
sheet warping at the side stops and the down-holder, respectively.
If a sheet is drawn into the printing unit in a warped condition,
however, this has a detrimental effect upon the feed register and
upon ghosting caused by the feeder.
SUMMARY OF THE INVENTION
[0006] It is accordingly an object of the invention to provide a
device for aligning sheets laterally which manages without a
down-holder in the region of the side stops.
[0007] With the foregoing and other objects in view, there is
provided, in accordance with one aspect of the invention, a device
for aligning sheets laterally on a feed table of a sheet-processing
machine, having a side stop, comprising a suction pull nozzle
movable transversely to a sheet transport direction and being
formed with a plurality of suction openings, the suction openings
being distributed so that the number of suction openings arranged
in the sheet transport direction becomes greater in a transverse
direction towards the side stop.
[0008] In accordance with another feature of the invention, the
suction openings are formed as suction bores.
[0009] In accordance with a further feature of the invention, the
suction bores have greater diameters in the direction towards the
side stop than towards a center of the feed table.
[0010] In accordance with an added feature of the invention, the
suction openings are distributed in the form of a triangle.
[0011] In accordance with an additional feature of the invention,
the suction openings are distributed in the form of a
semicircle.
[0012] In accordance with yet another feature of the invention, the
aligning device includes a suction chamber for supplying vacuum to
the suction bores, the suction chamber being divided into two
subchambers in the transverse direction, the suction chamber being
constructed so as to be disconnectable.
[0013] In accordance with yet a further feature of the invention,
the aligning device includes a slide operatable in an infinitely
variable manner in the transverse direction for closing the suction
bores.
[0014] In accordance with another aspect of the invention, there is
provided a device for aligning sheets laterally on a feed table of
a sheet-processing machine, having a suction pull nozzle movable
transversely to a sheet transport direction and having a plurality
of suction openings, comprising a side stop formed with a slope
extending in a direction of a sheet lateral edge.
[0015] In accordance with an added feature of the invention, an
imaginary extension of the slope forms an acute angle with a
transport plane of the feed table.
[0016] In accordance with a third aspect of the invention, there is
provided a device for aligning sheets laterally on a feed table of
a sheet-processing machine, having a side stop and a suction pull
nozzle movable transversely to a sheet transport direction, and
being formed with a plurality of suction openings, comprising a
run-on slope formed on the side stop, the run-on slope being
oriented counter to the sheet transport direction.
[0017] In accordance with another feature of the invention, the
run-on slope forms an acute angle with a sheet guide plane.
[0018] In accordance with a concomitant feature of the invention,
the run-on slope is constructed so as to extend below a sheet guide
plane.
[0019] A particular advantage of the invention is that a suction
force acting on the sheet through the suction nozzle is distributed
over suction openings in such a way that the number of suction
openings in the sheet transport direction is higher than in the
transverse direction, or is at least equally high. The sheet to be
transported is thereby held securely by the suction nozzle, with a
small total holding force, in particular in the edge region of the
sheet. Due to this measure, the sheet is able to execute a relative
movement with respect to the suction nozzle the instant the side
edge of the sheet contacts the side stop, so that the edge is not
damaged. The distribution of the suction force in accordance with
the invention, a greater suction force being provided in the edge
region of the sheet, causes the edge of the sheet not to wander
upwardly, even when it strikes the side stop. Therefore,
down-holders in the region of the side stops can be dispensed
with.
[0020] Dispensing with down-holders makes it possible for the sheet
that is transported away to slide over the side stops in order to
relieve stress. Run-on slopes advantageously arranged on the side
stops assist this measure.
[0021] Moreover, a further run-on slope directed counter to the
sheet transport direction is provided on the side stop, and makes
it possible for a laterally, negatively offset oncoming sheet not
to be caught or remain hanging on the side stop but to slide over
the latter. In order to rule out the possibility of the side stop
being a stumbling block, the run-on slope is formed to-extend below
the sheet guide plane.
[0022] Other features which are considered as characteristic for
the invention are set forth in the appended claims.
[0023] Although the invention is illustrated and described herein
as embodied in a device for aligning sheets laterally, it is
nevertheless not intended to be limited to the details shown, since
various modifications and structural changes may be made therein
without departing from the spirit of the invention and within the
scope and range of equivalents of the claims.
[0024] The construction and method of operation of the invention,
however, together with additional objects and advantages thereof
will be best understood from the following description of specific
embodiments when read in connection with the accompanying drawings,
wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a diagrammatic side elevational view of a
sheet-fed rotary printing machine incorporating a device for
aligning sheets laterally in accordance with the invention;
[0026] FIG. 2 is an enlarged cross-sectional view of FIG. 1,
showing the device for aligning sheets laterally in greater
detail;
[0027] FIG. 3 is a view like that of FIG. 2 showing another
embodiment of the device for aligning sheets laterally in
accordance with the invention, which has a suction chamber that is
divided, in contrast with the construction of FIG. 2;
[0028] FIG. 4 is a view like those of FIGS. 2 and 3 showing a third
embodiment of the device for aligning sheets laterally, which has a
slide;
[0029] FIG. 5 is a top plan view of a side stop having a suction
pull nozzle according to the invention;
[0030] FIGS. 6 to 8 are views like that of FIG. 5 showing further
embodiments of the suction pull nozzle;
[0031] FIG. 9 is a front, top and side perspective view of a side
or lateral stop according to the invention;
[0032] FIG. 10 is an end elevational view of FIG. 9 showing the
side or lateral stop, as viewed in the sheet transport
direction;
[0033] FIG. 11 is a side elevational view of FIG. 9 showing the
side or lateral stop in greater detail; and
[0034] FIG. 12 is a plan view of the sheet guide plane and the side
step disposed at the lefthand side of the figure.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] Referring now to the drawings and, first, particularly to
FIG. 1 thereof, there is shown therein, a rotary printing machine,
for example, a printing machine 1 for processing sheets 7, having a
feeder 2, at least one printing unit 3 and/or 4 and a delivery 6.
The sheets 7 are taken from a sheet pile 8 and, in separated or
overlapped relationship, are fed over a feed table 9 to the
printing units 3 and 4, which include, in a conventional manner,
plate cylinders 11 and 12, respectively, each of which has a device
13, 14 for fastening flexible printing plates thereon. Furthermore,
each plate cylinder 11, 12 has assigned thereto a respective device
16, 17 for changing printing plates semi-automatically or fully
automatically.
[0036] The sheet pile 8 lies on a controllingly liftable stacking
plate 10. The sheets 7 are taken from the top of the sheet pile 8
by a so-called suction head 18, which, among other parts, has a
number of lifting and dragging suckers 19 and 21 for separating or
singling the sheets 7. In addition, blowing or blast devices 22 are
provided for loosening the upper sheet layers, as are sensing
elements 23 for tracking the sheet pile 8. In order to align the
sheet pile 8, in particular, the upper sheets 7 of the sheet pile
8, a number of lateral and rear stops are provided.
[0037] The sheet 7 is fed over the feed table 9 to front alignment
devices in the form of so-called front guides or lays 26 and
aligned in circumferential direction at the front guides 26. A side
pulling device 25 has, among other parts, a suction pull nozzle 27
which is movable transversely to the sheet transport direction.
[0038] After the circumferential alignment is performed, the sheet
7 is subjected at a leading region thereof to suction by the
suction pull nozzle 27 disposed in the feed table 9, and is moved
in a pull channel 60 towards a lefthand or righthand side stop 28.
The movement of the suction pull nozzle 27 in the exemplary
embodiment according to FIG. 3 is performed by a respective control
roller 29, 30, which is in contact, during operation, with a
control contour of a respective axially aligned control cam 31, 32.
The control cams 31, 32, respectively, are seated on a control
shaft 33, 34 which is driven at the cycle speed rate of the
sheet-processing machine. The control shafts 33 and 34 can also be
formed as one common shaft.
[0039] The suction pull nozzle 27 is supplied with vacuum via a
suction connection, for example, via a respective control groove
36, 37 formed in the respective cyclically driven control shaft 33,
34.
[0040] The suction nozzle 27 has a number of suction bores 38,
which are arranged distributed in a movable pull plate 39 so that a
suction area Fs that acts upon the sheet 7 becomes larger in the
direction of the respective side or lateral stop 28.
[0041] According to the invention, for example, as shown in FIG. 5,
the number of bores 38 of equally large size which are arranged on
the pull plate 39 in the sheet transport direction B is equal to or
greater than the number of bores 38 of equally large size which are
arranged on the pull plate 39 in the transverse direction A. From
this, the ratio of the number of equally large bores 38 in the pull
plate 39 is B/A.gtoreq.1.
[0042] In a second embodiment, according to FIG. 6, the suction
area Fs is increased towards the edge region of the sheet 7, for
example, by making the bore diameters D in the pull plate 39
greater towards the side or lateral stop 28 than towards the center
of the feed table 9.
[0043] In a third embodiment, according to FIG. 7, the number of
equally large bores 38 in the pull plate 39 are greater towards the
side or lateral stop 28 than towards the center of the feed table
9. This can be achieved, for example, by a triangular pull plate 39
or a triangular distribution of the bores 38 in the pull plate
39.
[0044] In a fourth embodiment, according to FIG. 8, there is a
distribution of bores 38 of equal size in the pull plate 39
corresponding to a semicircular area, so that the number of the
equally large bores 38 is greater towards the side or lateral stop
28 than towards the center of the feed table 9.
[0045] In a further embodiment, as shown in FIG. 3, the suction
pull nozzle 27 is provided with two suction chambers 43 and 44
arranged transversely with respect to the sheet transport direction
B, i.e., in the lateral pulling direction A (in this regard, note
FIGS. 5 and 6). Depending upon the thickness of the printing
material, in particular when processing thick sheets, both suction
chambers 43 and 44 can be activated. When processing thin printing
materials, respectively, only the suction chamber 43 arranged
closer to the side or lateral stop 28 is activated, as a result of
which, the distribution of the holding force in the side region of
the sheet is greatest, with respect to the total holding force.
[0046] In a further embodiment, as shown in FIG. 4, for example, a
proposal is made to use a slide 46 arranged between the suction
openings and the respective suction chambers 43 and 44, the slide
46 being displaceable continuously in the direction of the side
stop 28 depending upon the thickness of the printing material to be
processed, so that during the processing of thin printing
materials, only the suction openings 38 which act upon the sheet 7
in the side region are effective and, during the processing of
thick printing materials, correspondingly more suction openings 38
are effective. The slide 46 is arranged to be adjustable via a
setting motor 47 and is set automatically by the control system 48
of the printing machine depending upon the thickness of the
printing material to be processed.
[0047] A surface of the pull plate 39 lies in a plane with the feed
table 9 and, during the side pulling operation, slides underneath
the side stop 28. The side stop 28 has a stop face 41 disposed
vertically with respect to the sheet guide plane 50. This face 41
extends upwardly from the sheet guide plane 50 and ends there in a
slope 42, an imaginary extension of which forms an acute angle with
the sheet guide plane 50. The slope 42 assists in the relief of
stress in the sheet as the latter is conveyed away, it being
possible for the sheet to slide over the side stops 28 during the
process.
[0048] A further, so-called run-on slope 49 on the side stop 28 is
arranged counter to the sheet transport direction. The run-on slope
49 extends beneath the sheet guide plane 50, as shown in FIG. 11,
in order that no stumbling block be presented to the sheets
conveyed up to the front guides. The run-on slope 49 encloses an
acute angle .beta. with the sheet guide plane 50.
[0049] The task of the run-on slope 49 is to permit sheets which
arrive with a lateral offset to slide over the side stop 28. This
measure prevents the oncoming sheet from being caught on the side
stop 28 and, as a result, being skewed on the sheet guide plane 50
which, in the least favorable case, can lead to an interruption in
the sheet feed.
[0050] Provision is made for sheets conveyed to the front guides
with a negative lateral offset to be detected by a non-illustrated
feed monitoring device, and for a signal to be given to the
delivery 6 which, for example, ensures that a tab be fired into the
delivery pile at an appropriate point, so that the sheet which has
been slid over the side stop 28 without being aligned can be
removed.
* * * * *