Sheet-material associating – Associating or disassociating – Signature associating
Reexamination Certificate
2000-12-01
2003-04-15
Eickholt, Eugene H. (Department: 2854)
Sheet-material associating
Associating or disassociating
Signature associating
C493S424000
Reexamination Certificate
active
06547232
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to printing presses and more particularly to a folder of a printing press.
2. Background Information
Web printing presses print a continuous web of material, such as paper. In a folder of the printing press, the continuous web then is cut into signatures in a cutting unit and folded.
One way to fold the resulting signatures is using a rotary blade folder, which includes a folding cylinder with tucker blades which provide a fold to the signature. The fold is forced by the tucker blade toward two rotating fold rolls, which grip the signature along the fold at a nip, set the fold and deliver the folded product, for example, to a fan unit.
Chapter 6 (pages 136 to 154) of the book “Newspaper Presses” by William Braasch describes the two basic kinds of rotary blade folders: 2 to 1 folders and 3 to 2 folders. In a 2 to 1 rotary blade folder, two sets of tucker blades are spaced 180 degrees apart on the folding cylinder. A signature is held by pins spaced 90 degrees ahead of a tucker blade set and when the signature midpoint reaches the fold rollers, the tucker blade pushes the signature at the midpoint into the fold rollers so as to form the fold. Thus in a 2 to 1 folder, two sets of pins spaced 180 degrees apart are present, for holding edges of the products to be folded. In a 3 to 2 folder, three sets of pins spaced 120 degrees apart are present. Sets of tucker blades operate at a midpoint of a signature to produce a fold by pushing the midpoint into a pair of fold rollers.
In order to increase a page count of a product, folders in a printing press utilize a method of collecting sheets to form a larger product. To accomplish the collection of sheets, a tucker blade is silenced so that it does not perform a tucking operation into nip rollers and the pin holding the lead edge of the signature is not retracted. The silencing, which occurs in collect mode, permits the product to remain on a folding cylinder so that the folder is supplemented with additional sheets as a result of the folding cylinder rotating another revolution. When two sheets are collected by the cylinder, the two sheets may then be released by the pin and folded by the tucking blade. The collect mode is in contrast to the straight mode during which no folding blades are silent and no products are permitted to remain on the cylinder, so that each pin retracts every revolution. The switch from collect mode to straight mode or vice versa is called a changeover.
One way to move the pins on the rotary blade folder is with a rotating box cam.
FIG. 1
shows the straight mode in a prior art three-to-two rotary blade folder
10
with a rotating box cam
20
for moving the pins. The cam makes a ½ rotation for every one third revolution of the pins and the cam followers. Pins
1
,
2
and
3
are connected to and activated by cam followers
11
,
12
and
13
, respectively, and thus rotate together about the axis of the folder, although the cam followers
11
,
12
,
13
generally lag the pins
1
,
2
,
3
a few degrees due to the structure of the connection. The cam follower
11
,
12
,
13
and rotating cam
20
movement is displayed underneath the folder
10
for clarity. When a cam follower
11
,
12
or
13
meets one of two raised sections
21
or
22
in the rotating box cam, the respective pin
1
,
2
or
3
is retracted. Thus in section A of
FIG. 1
, pin
3
is retracted when cam follower
13
meets raised section
21
. Signature
100
thus is released by pin
3
, is tucked and folded by folding rolls
30
. In section B, when raised section
22
(traveling faster than follower
12
) and follower
12
meet, pin
2
is retracted as a next signature
101
is released, tucked and folded. In section C, pin
1
is retracted when follower
21
meets raised section
21
. Next signature
102
is thus released by pin
1
. In section D, pin
3
is again retracted, this time raised section
22
reaching follower
13
. The cam followers may include two parallel rollers running in associated grooves slightly offset from one another.
To switch over to a collect mode, an operator disengages one of the tucking blades, stops the machine and physically removes one of the raised cam sections
21
,
22
and replaces it with a non-raised section. Because the box cam and the cam follower are moving, it has generally not been possible to permit automatic switching between the collect and straight modes.
FIG. 2
shows a prior art collect mode with section
22
raised section removed and replaced by a non-raised section
23
. In Section I of
FIG. 2
, pin
2
does not retract as a signature
104
passes by the folding rollers
30
, because cam follower
12
is met by non-raised section
23
which does not actuate the pin
2
. One of the tucking blades, which has be deactivated by another mechanism, also does not tuck. Thus signature
104
remains on the folder
10
, as a signature
105
previously did. As shown in Section II, signature
105
thus is joined by a new second signature
106
, as cam follower
11
reaches raised section
21
. Pin
1
thus releases the lead edge of signatures
105
and
106
. The two signatures
105
,
106
, properly collected, then are tucked by the activated tucking blade, and folded by folding rolls
30
. As shown in Section III, signature
107
remains held by pin
3
on folder
30
since non-raised section
23
passes by cam follower
13
. Signature
104
is joined by a new signature
108
, which together then are folded when the signatures
104
and
108
are tucked. Pin
2
at the same time retracts as cam follower
12
and raised section
21
meet in Section IV. The collect action thus continues in this fashion.
The switch-over from a straight to a collect run using the box cam as shown in
FIGS. 1 and 2
however is time-consuming and complicated. An operator manually switches the components, e.g. replaces raised section
22
with non-raised section
23
. Moreover, if the parts do not fit properly or are misplaced, valuable time can be lost.
U.S. Pat. No. 5,797,319 purports to disclose a drive device for a folder in a printing press having a folding blade mounted to a folding blade shaft. A drive gear drives a folding blade shaft gear. The drive device also includes a plunger having an intermediate gear between the gear of the folding blade shaft and the drive gear, and a device for moving the plunger between a first longitudinal position and a second longitudinal position. In the first longitudinal position, the intermediate gear meshes with the folding blade shaft gear, whereas in the second longitudinal position, the intermediate gear is out of register with the drive gear. The drive device may also include a cam and an indexing ring operable in response to axial movement of the plunger. During the outward movement of the plunger caused by a helical spring, the cam race is contacted by the pin causing the cam index to rotate. Rotation of the cam permits further outward axial translation of the plunger, because the pin slidably engages different portions of the cam race as the pin continues to rotate. A first stop in the cam race corresponds to the plunger being in the first longitudinal position, and a second stop in the cam race corresponds to the plunger being in the second longitudinal position.
The device of the '319 patent does not address the problem of prevent pins from retracting during a changeover, but rather only seems to address the tucking motion. Moreover, the device requires a complex arrangement of parts.
Commonly-assigned U.S. Pat. No. 6,093,139 (which is not necessarily prior art to the present application) purports to disclose a product cutting device for flat material. A first and second cam follower assigned to a respective first and second cam move a lever and a further lever about a first and second pivot axis. By the first cam, a product seizing element is moved upon the surface of a cylinder in a direction opposite to the direction of rotation. A further lever assigned to
Herda Philippe Francois
Miescher Christian Heinz
Davidson Davidson & Kappel LLC
Eickholt Eugene H.
Heidelberger Druckmaschinen AG
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