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Description  |
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FIELD OF THE INVENTION
The present invention relates generally to an apparatus for cutting and
folding a web of material, and more particularly to a folder in a rotary
offset printing press.
BACKGROUND OF THE INVENTION
Known folders in rotary offset printing presses convert a continuous web of
printed paper into a series of books or pamphlets folded according to
various types of folds. These machines usually make two folds: the first
fold is a cylinder fold or tabloid fold, and the second fold may be either
a parallel fold or delta fold. The second fold is typically made so that
point holes formed on the web appear on the inside of the final product.
The web is generally already folded in half before entering the folder by
a device called a former. The former continuously folds the web in the
longitudinal direction so that a fold parallel to the edges of the web
width is created.
Because of various customer demands, it is necessary that folders be able
to make both second parallel folds and delta folds. Therefore, such
folders must be able to assume two different configurations which are
necessary for making both types of folds.
These folders are comprised of a cutting cylinder, a transfer cylinder, a
first-fold cylinder, and a second-fold cylinder. The cutting cylinder has
a cutting blade which engages with a cutting counterpart on the transfer
cylinder for cutting the web into signatures. The transfer cylinder is
equipped with pairs of spur bars and engaging blades which cooperate with
first-fold jaws on the first-fold cylinder for forming a first fold in the
signature. The first-fold cylinder is equipped with pairs of first-fold
jaws and second fold jaws which cooperate with pairs of grippers and
engaging blades disposed on the second-fold cylinder for forming a second
fold in the signature.
The spacing between each of the respective pairs of elements of the
respective cylinders determines the type of fold that is created.
Therefore, in order to change the type of fold made, the spacing between
the respective elements must be altered. This change can translate into
angular displacements of between 10.degree. and 20.degree. to convert the
folder from a configuration which forms second parallel folds to one that
forms delta folds.
These angular displacements are far greater than the angular displacement
that these cylinders are generally capable of when each of the cylinders
is produced in two imbricated independent parts movable relative to one
another and equipped with respective driving gears. In fact, such a form
of construction is often employed to make it possible to adjust the lap
length by introducing a slight angular offset (typically only a few
degrees) between the respective driving gears, these gears moreover being
coupled to one another two-by-two in order to preserve coincidence between
the elements which must cooperate with one another during the passage of
the paper web between two adjacent cylinders. To adjust the lap length, a
single double-helical pinion is used which is driven by each respective
pair of gears of the relevant cylinder during the normal operation of the
folder. One portion of this pinion meshes with one of the gears, and the
other portion meshes with the other gear. The operator effects a slight
axial translational movement of this double.helical pinion, the axis of
which remains parallel to that of the relevant Cylinder, thereby making it
possible to obtain a slight angular displacement in the desired direction
between the associated pair of gears. However, such a relative angular
adjustment can only be used for displacements of a few degrees.
Therefore, this technique for adjusting the lap length is virtually
impractical for the purpose of obtaining angular displacements of the
magnitude of 10 to 20.degree.. To obtain angular displacements of 10 to
20.degree., a translational movement of a length ten to twenty times
greater than that which the double.helical pinion is capable, may be
necessary. Although that solution is theoretically possible, it is
typically not used in practice, because the lateral bulk of the folder is
considerably increased.
This explains why, in conventional folders, the removal of the various
groups of elements on the relevant cylinders is carried out manually. In
fact, an operator usually has to remove all the first-fold engaging blades
from the transfer cylinder in order to readjust them in relation to the
spur bars, all the second-fold jaws of the first-fold cylinder in order to
readjust them in relation to the first-fold jaws, and all the second fold
engaging blades of the second-fold cylinder in order to readjust them in
relation to the grippers. These operations are complicated, involve the
use of various tools and cause a rather lengthy operational shutdown of
the press.
Various other solutions have also been proposed for modifying the
configuration of a universal folder for the purpose of obtaining either a
second parallel fold or a delta fold., For example, some use one or more
specialized cylinders for the delta fold and other specialized cylinders
for the second parallel fold. Although this may avoid the individual
operations of removing and refitting the elements of these cylinders, it
nevertheless still involves shutting down the machine and manually
substituting the specialized Cylinders. This solution is incomplete, since
operator intervention is still necessary, a relative long shut down is
still required, and specialized cylinders are required.
Another proposed solution involves rotating the various parts of the
cylinders by means of complex drives, e.g., "harmonic drives". However,
this solution is costly and complex.
Therefore, all of these solutions are either difficult to put into
practice, requiring manual intervention inside the machine, or are costly
and complex.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to provide a universal folder, the
structure of which can easily be modified to change folding formats, that
is automatic, requires minimal machine down time, and that is simple and
cost effective.
Another object of the present invention is to provide a folder, having a
structure which makes it possible to easily vary to a large extent the
position in which the various folds are formed.
A further object of the present invention is to maintain all the gears
constituting the cinematic chain of the folder in intimate contact and to
prevent the takeup of the gear backlash during the acceleration or
deceleration of the printing press.
The present invention provides an apparatus for cutting and folding a web
of material, comprising: a transfer cylinder having at least one spur bar
and at least one associated engaging blade disposed thereon; a first-fold
cylinder adjacent to the transfer cylinder having at least one first-fold
jaw and at least one associated second fold jaw disposed thereon; and a
second-fold cylinder adjacent to the first-fold cylinder having at least
one gripper and at least one associated engaging blade disposed thereon,
the transfer, first-fold and second-fold cylinders each being defined by
two imbricated independent parts, an inner part and an outer part,
moveable relative to one another, each independent part having an
associated drive gear, the drive gears of the respective cylinders being
coupled to one another two-by-two so that coincidence between the
cylinders is preserved, the drive gears of the transfer cylinder being
connected to one another by a first pair of coupling gears coaxial
relative to one another and interconnected by a first disengageable
coupling for disengaging the first pair of coupling gears when changing
the apparatus from one folding mode to another so that the inner and outer
parts of the transfer cylinder can rotate relative to one another, and the
drive gears of the first-fold cylinder being connected to one another by a
second pair of coupling gears coaxial relative to one another and
interconnected by a second disengageable coupling for disengaging the
second pair of coupling gears when changing the apparatus from one folding
mode to another so that the inner and outer parts of the transfer cylinder
can rotate relative to one another.
The present invention further provides an adjustment means, connected to
the drive gear of the inner part of the transfer cylinder and to the drive
gear of the outer part of the second-fold cylinder, for varying the
angular displacement between the pairs of elements of the respective
cylinders when the first and second disengageable couplings are in a
disengaged position so as to convert the apparatus from one folding mode
to another.
Other characteristics and advantages of the present invention will become
apparent from the following description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1a-c are a diagrammatic view illustrating the steps in forming a
first cylinder fold and a second parallel fold on a copy (Prior Art);
FIGS. 2a-c are a diagrammatic view illustrating the steps in forming a
delta fold on a copy (Prior Art);
FIG. 3 is a view of a known folder configuration which forms a second
parallel fold (Prior Art);
FIG. 4 is a view of a known folder configuration which forms a delta fold
(Prior Art);
FIG. 5 is a perspective view of an axial section of a transfer cylinder
(Prior Art);
FIG. 6 is a diagrammatic view illustrating, in elevation, gears of a folder
according to the present invention;
FIG. 7 is a schematic view of the folder according to the present
invention;
FIG. 8 is a partial view illustrating a particular embodiment of a
disengageable coupling of the folder according to the present invention;
FIGS. 8a and 8b are two laid-out sectional views illustrating a claw of the
disengageable coupling in FIG. 8 in he engaged position (8a) for one of
the two configurations of the folder and in the disengaged intermediate
position (8b) during a change of the configuration;
FIG. 9 is a sectional view of a particular embodiment of an adjustment
means which varies the angular displacement between the pairs of elements
of the relevant cylinders; and
FIG. 10 is a partially cut away perspective view illustrating the closed
loop of gears of the present invention according to the embodiment of FIG.
7.
DETAILED DESCRIPTION
FIGS. 1 and 2 illustrate the successive steps in the formation of a
parallel fold and a delta fold, respectively. In FIG. 1 a printed copy
receives a first cylinder fold and a second parallel fold. At A) is shown
a copy E, such as is obtained after the cutting of the web as it passes
between a cutting cylinder and a transfer cylinder of the folder, the copy
having a cutting length c. The copy E has marks r, represented by dots,
which correspond to the holes created by spurs on the transfer cylinder
which secure the copy to the surface of the transfer cylinder. The copy E
can be either a single web or a double web already folded by a former, in
which case one of the longitudinal edges corresponds to the fold made by
the former. At B), the copy E has undergone a folding in the middle of its
length to c/2 by passing between the transfer cylinder and a first-fold
cylinder of the folder. At C), the copy E has once again undergone a
mid-length folding, thus reducing its length to c/4, by passing between
the first-fold cylinder and a second-fold cylinder of the folder. This
second fold is called the "second parallel fold". The folds are made so
that the holes r end up on the inside of the finished product.
Similarly, FIG. 2 illustrates the formation of a delta fold from a copy E,
as described in connection with FIG. 1, and having a cutting length c,
after a passage of the web between the cutting cylinder and the transfer
cylinder, as illustrated at A). At B), the copy E has undergone a folding
similar to the first fold described in connection with FIG. 1, but this
first fold is made over the first third of the length of the copy to c/3,
after passage between the transfer cylinder and the first-fold cylinder.
The length of the copy is then 2c/3. In order to carry out this folding,
it is necessary to modify the configuration of the transfer cylinder in
relation to that used for the first folding carried out according to FIG.
1. The configuration of the first-fold cylinder likewise has to be adapted
accordingly, as will be described below. At C), the copy has undergone a
second folding, again to c/3, but this time with respect to the other part
of the cut web: this results in a second fold, called a delta fold, and
the copy has a length of c/3. Since this delta fold is obtained by the
passage of the cut web between the first-fold cylinder and the second-fold
cylinder of the folder, it will therefore be appreciated that the
configuration of these cylinders also has to be modified in relation to
that for making a second parallel fold corresponding to FIG. 1.
A conventional folder is illustrated in FIG. 3. This folder comprises a
triangle 1, which forms a longitudinal fold in the continuously travelling
web of material 4. Such a former is well known to those skilled in the art
and is not part of the present invention. The web 4 is fed into the folder
by two pairs of draw rollers 2, 2' and 3, 3' having elastomeric surfaces
pressed against one another.
The web 4 first passes between a cutting cylinder 5 and a transfer cylinder
6. A cutting blade 7 disposed along one of the generatrices of the cutting
cylinder 5 cooperates with rubber blade counterparts 8, 8' and 8',
disposed on the periphery of the transfer cylinder 6. Preferably, the
circumference of the cutting cylinder 5 is equal to the length c of the
copy, so that exactly one copy is cut per rotation of the cutting
cylinder.
The circumference of the transfer cylinder 6 is preferably equal to two or
three times the length c of the copy (three times in FIG. 3). The transfer
cylinder 6 has spur bars 9, 9' and 9', defined by a plurality of small
needles projecting through the cylinder which penetrate into the paper web
immediately before the web is cut by the cutting blade/cutting counterpart
pair. Thus, the paper web 4, passing between the cutting cylinder 5 and
the transfer cylinder 6, is cut by the cutting blade 7 which penetrates
into the associated cutting counterpart 8, 8' or 8", thereby producing
separate copies retained on the transfer cylinder 6 by the associated
spurs 9, 9' and 9".
The transfer cylinder 6 also has engaging blades 10, 10' and 10" disposed
on its periphery at a location corresponding to half the length of each of
the copies, i.e., c/2, for introducing the copies into associated jaws 11,
11' and 11" disposed on a first-fold cylinder 12. The transfer cylinder 6
is thus equipped with pairs of spur bars and engaging blades, each pair of
elements taking the place of the preceding one for every rotation of
120.degree.. The spacing between the space bars and the engaging blades of
the transfer cylinder 6 is equal to a length of c/2, which corresponds to
an angular displacement of 60.degree..
The web 4 next passes between the transfer cylinder 6 and a first-fold
cylinder 12 which is defined by first-fold jaws 11, 11' and 11" intended
for cooperating with the engaging blades 10, 10' and 10" on the transfer
cylinder 6, and second-fold jaws 15, 15' and 15" intended for cooperating
with engaging blades 18 and 18' provided on a second-fold cylinder 16. In
the embodiment illustrated in FIG. 3, the first fold jaws 11, 11' and 11",
are each defined by a stationary part 13 which is integral with the
first-fold cylinder 12 and against which a blade 14 (know as a "tucking
blade") oscillates. The structure of the second-fold jaws 15, 15' and 15"
is preferably identical to that of the first-fold jaws 11, 11', and 11".
The first-fold cylinder 12 is therefore equipped with pairs of first-fold
jaws and of second-fold jaws. The spacing between the first-fold jaws and
the second-fold jaws, is equal to a length of c/4, which corresponds to an
angular displacement of 30.degree..
The second fold cylinder 16 adjacent to, and parallel to, the first-fold
cylinder 12 cooperates with the first-fold cylinder and comprises grippers
17 and 17' which cooperate with the first-fold jaws 11, 11', and 11" of
the first-fold cylinder 12. When a first fold jaw passes through the
centerline between the first-fold cylinder 12 and the second-fold cylinder
16, this jaw opens, simultaneously the corresponding gripper of the
second-fold cylinder 16 closes and grasps the copy already folded once. To
form the second fold, the second fold cylinder 16 likewise includes
engaging blades 18 and 18' which cooperate with the second-fold jaws of
the first-fold cylinder 12 when these two elements pass through the
centerline of the cylinders, while the associated gripper, by opening,
releases the first fold of the copy. The spacing between the grippers and
the engaging blades on the second fold cylinder is equal to a length of
c/4, which corresponds to an angular displacement of 45.degree..
Thus, the cutting cylinder 5/transfer cylinder 6 pair cut the copies and
wind them around the transfer cylinder 6, where they are retained at their
heads by the spurs 9, 9' and 9". The transfer cylinder 6/first-fold
cylinder 12 pair subsequently form the first fold of the copy and retain
this folded copy in the first fold jaws 11, 11' and 11" of the first-fold
cylinder. The process of forming the second fold then takes place as
follows: The head of the copy (first fold) is held at the start of the
cycle in the associated first-fold jaw of the first-fold cylinder 12, and
the relevant gripper of the second-fold cylinder 16 grasps it as it passes
through the centerline. Rotation subsequently continues, and the
associated engaging blade of the second-fold cylinder 16 then engages the
copy into a second fold jaw of the first-fold cylinder 12, this jaw
closing during the passage of these two elements through the centerline,
while the gripper, by opening, releases the first fold of the copy. At the
end of the cycle, there is a copy which has received two folds parallel to
one another and perpendicular to the direction of travel of the paper web
and which is clamped by means of its second fold in the associated
second-fold jaw of the first-fold cylinder 12.
A set of strippers 19 protruding into grooves formed in the first-fold
cylinder 12 extract the copies and direct them into a slowly rotating star
wheel or fan 20 which deposits them onto a conveyor belt 21 so that the
copies overlap one another.
Therefore, when a second parallel fold is to be made, the folder is
arranged such that the pairs of elements of the transfer cylinder, of the
first-fold cylinder and of the second-fold cylinder have a spacing equal
to c/2, c/4 and c/4, respectively, which corresponds to angular
displacements of 60.degree., 30.degree. and 45.degree..
If a delta fold is desired, then it is necessary to modify the
configuration of the folder. This entails changing the angular
displacements between the pairs of elements of the transfer, first-fold
and second-fold cylinders. FIG. 4 illustrates a configuration of the
folder for forming delta folds. The spacings between the pairs of elements
of the transfer cylinder 6, of the first-fold cylinder 12, and of the
second-fold cylinder 16 become c/3, c/3 and c/3, respectively, which
correspond to angular displacements of 40.degree., 40.degree. and
60.degree..
In order to change from one configuration of the folder to another, changes
in angular displacements between the respective pairs of elements of each
of the cylinders are significant. With respect to the transfer cylinder 6,
the spacing between each spur bar and each corresponding engaging blade
must change from c/2 to c/3, which corresponds to an angular change from
60.degree. to 40.degree., a difference of 20.degree.. With respect to the
first-fold cylinder 12, the spacing between each first-fold jaw and each
corresponding second-fold jaw must change from c/4 to c/3, which
corresponds to an angular change from 30.degree. to 40.degree., a
difference of 10.degree.. Finally, with respect to the second-fold
cylinder 16, the spacing between each gripper and each corresponding
engaging blade must change from c/4 to c/3, which corresponds to an
angular change from 45.degree. to 60.degree., a difference of 15.degree..
FIG. 5 illustrates the structure of the transfer cylinder 6. This figure
shows only one spur bar 9 and one engaging blade 10. To allow the relative
displacement of the elements of the same type (spur bars or engaging
blades) three by three, the transfer cylinder is formed into two
imbricated independent parts, an inner part and an outer part, movable
relative to one another and equipped with respective driving gears,
according to the technique already adopted in known folders for obtaining
an adjustment of the "lap length". This structure makes it possible to
obtain a displacement of the three engaging blades 10, 10' and 10"
relative to the three spur bars 9, 9' and 9".
The inner part is defined 50 and 50' welded to a shaft 51. The flanges 50
and 50' are connected to one another by three longitudinal plates (of
which only one designated by 53 is illustrated) welded at 120.degree., in
order to form part of the periphery of the transfer cylinder. The spur
bars 9 are pivoted on the flanges 50 and 50'.
The outer part is defined by two flanges 54 and 54' mounted rotatably on
the shaft 51. The flanges 54 and 54' are connected to one another by three
longitudinal plates, of which only one designated by 55 is illustrated.
The engaging blades 10 are mounted on these longitudinal plates. The
flange 54 is extended externally and axially by a tubular extension 56,
itself mounted rotatably on the shaft 51. A gear 52 is keyed onto one end
of the shaft 51 and a gear 57 is keyed onto the tubular extension 56. The
gear 52 directly drives the inner part carrying the spurs, while the gear
57 directly drives the outer part carrying the engaging blades. The
driving gears 52 and 57 are preferably of the helical type, one having a
left-handed helix and the other a right-handed helix, for reasons which
will be explained below.
The first-fold cylinder 12 is constructed in the same way as the transfer
cylinder 6 illustrated in FIG. 5, with the first-fold jaws 11, 11' and 11"
being disposed on the inner part and the second-fold jaws 15, 15' and 15"
being disposed on the outer part.
The second fold cylinder 16 is also constructed in a similar manner with
the grippers 17 and 17' being disposed on the inner part and the engaging
blades 18 and 18' being disposed on the outer part. However, since the
second-fold cylinder 16 has a symmetry of the order of two rather than of
the order three, only two sets of longitudinal plates are needed to
connect the respective flanges of the inner parts and outer parts.
Therefore, FIG. 5 which illustrates the particular structure of the
transfer cylinder 6, also serves for describing the structure of the
first-fold cylinder 12 and the second-fold cylinder 16. The respective
driving gears, which can be seen in FIG. 7, are gears 65 and 66 for the
first-fold cylinder 12 and gears 74 and 75 for the second-fold cylinder
16.
The structure of the means for modifying the configuration of the folder
for the purpose of obtaining either a second parallel fold or a delta
fold, which constitutes part of the present invention, will now be
described in detail with reference to FIGS. 6 to 10.
FIG. 7, which is a planar view of a known folder incorporating the present
invention and of which the line in FIG. 6 corresponds to the sequence A,
B, C, D, M, L, R, illustrates, in section, the various cylinders of the
folder, their shafts, connecting gears and the cams controlling the
shafts. There can thus be seen the cutting cylinder 5 with its cutting
blade 7, the transfer cylinder 6, the inner part of which carries the spur
bars 9, 9' and 9" and the outer part of which carries the engaging blades
10, 10' and 10", the first-fold cylinder 12, the inner part of which
carries the first-fold jaws 11, 11' and 11" and the outer part of which
carries the second fold jaws 15, 15' and 15" and the second-fold Cylinder
16, the inner part of which carries the grippers 17 and 17' and the outer
part of which carries the engaging blades 18 and 18'.
FIG. 7 also shows an assembly of the various gears associated with each
cylinder, these gears having, as appropriate, a left-handed helix
(designated by the letter G) or a right-handed helix (designated by the
letter D). There can thus be seen the gear 76 keyed on the shaft of the
cutting cylinder 5, the coaxial gears 52 and 57 associated with the two
parts of the transfer cylinder 6, the coaxial gears 66 and 65 associated
with the two parts of the transfer cylinder 12, and finally the gears 74
and 75 associated with the two parts of the second-fold cylinder 16.
The present invention provides that, the driving gears 52, 57 of the two
independent parts of the transfer cylinder 6 and the driving gears 66, 65
of the two independent parts of the first-fold cylinder 12 are connected
to one another by respective pairs of gears 59, and 68, 67 coaxial
relative to one another and interconnected by disengageable couplings.
During normal operation, the corresponding couplings are in the engaged
position and the respective pairs of gears 59, 58 and 68, 67 form an
assembly integral in terms of rotation. In this case, the folder is driven
by a pinion 77 which in turn is driven by a Cardan transmission 78
connected to an electric motor which drives the printing press. The pinion
77 meshes with the gear 52 connected to the inner part of the transfer
cylinder 6. The gear 52 drives both the gear 76, which in turn drives the
cutting cylinder 5, and the pair of gears 59, 58, which in turn drive the
gear 57 of the transfer cylinder 6, thus ensuring the drive of the
transfer cylinder. The gear 57 then drives the gear 66, which in turn
drives the engaged pair of gears 68, 67, which in turn drive the gear 65,
thus ensuring the drive of the first-fold cylinder 12. The gears 66 and 65
mesh with the gears 74 and 75, respectively, and thus ensure the drive of
the second fold cylinder 16.
By disengaging the coupling of the gears of each respective pair 59, 58 and
68, 67, it is possible to temporarily disconnect the coupling connections
between the pairs of gears 52, 57 or 66, 65 of the transfer cylinder 6 or
of the first-fold cylinder 12, respectively, thus allowing a perfect
angular adjustment of the pairs of relevant elements of each of the three
relevant cylinders for the purpose of modifying the configuration of the
folder to obtain either a second parallel fold or a delta fold. The
disengagement is preferably accomplished by associated actuation means.
There are, of course, a plurality of means which can be used for
disengaging the coupling between each respective pair of gears 59, 58 and
68, 67. Such a disengageable coupling could be provided by, for example,
an associated indexed magnetic denture clutch.
FIG. 7 shows a disengageable coupling provided by a claw 60 for the pair of
gears 59, 58 and a claw 69 for the pair of gears 68, 67, each claw having
two fixed positions limited by two abutments and corresponding to one or
the other of the configurations of the folder for the purpose of obtaining
either a second parallel fold or a delta fold. Thus, each respective pair
of gears 59, 58 and 68, 67 constitutes an actual fold-adjusting device.
The claws 60 and 69 can be controlled manually by an operating wheel or by
a pneumatic or hydraulic air cylinder or by an electromagnet or by any
other control means. FIG. 7 shows means of control by a double-acting air
cylinder 61 and an associated linkage 62 for the claw 60 and a
double-acting jack 70 and an associated linkage 72 for the claw 69.
The structure of these disengageable couplings can be more clearly
understood by reference to FIG. 8 which illustrates the means associated
with the pair of gears 59, 58 associated with the transfer cylinder 6.
Identical means are used for the other pair of gears 68, 67 associated
with the first-fold cylinder 12.
FIG. 8 shows an associated shaft 163 which is fastened to the frame of the
folder and on which a sleeve 102 is rotatably mounted by a roller bearing
103. The gear 58 is securely mounted on the sleeve 102. In contrast, the
gear 59 is rotatably mounted on the sleeve 102 with a bronze ring 104 and
a stop ring 105, respectively, ensuring the rotation and translational
immobilization of the gear on the sleeve.
A collar 101, keyed freely on the sleeve 102 by mean of an associated key
114, constitutes the movable element of the Claw 60. The collar 101
comprises a plurality of plunger pistons 107 subjected to the action of
associated springs 115, the free end of the pistons bearing against a
washer 106 fastened to the upper part of the sleeve 102. The collar 101
can thus occupy two axial positions, a low position corresponding to an
engaged position of the claw 60, and a high position in abutment against
the bearing washer 106 corresponding to a disengaged position of the claw.
The air cylinder 61 and the associated linkage lever 62 cooperate to
displace the collar 101 between these two axial positions.
FIG. 8a is a laid-out view of the interlocked position illustrated in FIG.
8 which shows a finger 108 projecting below the collar 101 which can
penetrate either into a notch 109 or into a notch 110 of the gear 59. Each
notch corresponds to the relative angular positions between the collar 101
and the gear 59, and hence between the gears 58 and 59. Each notch also
corresponds to the respective configurations of the folder for the purpose
of obtaining either a second parallel fold or a delta fold.
When the air cylinder 61 is actuated to disengage the coupling obtained by
the claw 60, the collar 101 is in abutment against the associated washer
106 and the finger 108 is released from the notch 109, so that the finger
can pass over an intermediate surface 111 between the notches 109 and 110,
while at the same time remaining below the peripheral surface 112 of the
gear 59, as illustrated in FIG. 8b. Thus, the finger 108 of the collar 101
has an angular displacement limited by its two end abutment positions in
line with the two notches 109 and 110. The passage from one notch to the
other when the claw 60 is disengaged is obtained by associated adjustment
means which will be described later.
FIG. 8 further shows a device for additional adjustment corresponding to a
fine adjustment of the "lap length" of the copy. The shaft 163 terminates
at threaded end 63, onto which is screwed an adjusting wheel 64, the axial
position of which is ensured by a locking counternut 113. An
angular-contact ballbearing 100 defined by an outer ring and inner ring is
provided between the wheel 64 and the sleeve 102, the outer ring of the
bearing is clamped between the washer 106 and the sleeve 102, and the
inner ring is integral with the wheel 64.
By releasing the counternut 113, it becomes possible to rotate the wheel 64
in one direction or the other which axially displaces the sleeve 102, and
therefore the gears 58 and 59 connected to it. Since the gears 58 and 59
are helical in opposite directions (gear 58 is a left-handed helix and
gear 59 is a right-handed helix), this axial movement of the sleeve 102 in
relation to the shaft 163 gives rise to a relative rotational movement
between the gearwheels 52 and 57 and consequently a relative movement
between the engaging blades and the spur bars of the transfer cylinder 6.
The rotation of the wheel 64 can be carried out either by hand or by means
of an associated motor allowing remote adjustment.
A device with the same structure and the same mode of operation as the one
which has just been described with respect to the transfer cylinder 6 with
reference to FIG. 8, is used for adjusting the projecting lap of the
second fold in the region of the first-fold cylinder 12. FIG. 7 shows the
wheel 73 which is similar to the wheel 64. By rotating the wheel 73, it is
possible to displace the two helical gears 68, 67 axially and to execute a
relative rotational movement between the gears 66 and 65, thus displacing
the first-fold jaws relative to the second-fold jaws on the first-fold
cylinder 12.
The overall translational movement of one or the other respective pair of
gears 59,, 58 or 68, 67 executed for such an adjustment of the lap length
results in angular displacements of only a few degrees, and hence can only
be used to make fine adjustments.
The structure of the adjustment means, which makes it possible to vary the
angular displacement between the pairs of elements of the transfer
cylinder 6, the first-fold cylinder 12 and the second-fold cylinder 16, so
as to convert the folder from a second fold mode to a delta fold mold,
also constitutes part of the present invention and will now be described.
According to a preferred embodiment illustrated in FIG. 7, this adjustment
means comprises a reversible screw/nut system 80, the screw of which
carries one gear 87 and the nut of which carries another gear 86, and an
associated air cylinder 90 making it possible to bring these two
concentric gears 87, 86 towards or away from one another, in order to
generate a torque between them in one direction or the other according to
the desired configuration. The gear 86 is connected to the gear 52 which
is connected to the inner part of the transfer cylinder 6, whereas the
gear 87 is connected to the gear 75 which is connected to the outer part
of the second-fold cylinder 16, in order to form a closed loop.
The reversible screw/nut system is connected to the gears 52 and 75 by
means of intermediate gears 81 and 79 pivoted on the frame of the folder,
as shown in FIG. 7. The gear 79 meshes with the gear 75 of the second-fold
cylinder 16 and the gear 81 meshes with the gear 52 of the transfer
cylinder 6, the latter meshing connection being represented
diagrammatically in FIG. 7 by a dot-and-dash line 200. The exact structure
of the reversible screw/nut system 80 is better illustrated in FIG. 9
which will now be described.
The reversible screw/nut system 80 is a torque-generating device for
modifying the configuration of the folder for the purpose of obtaining the
desired second fold, which comprises a hollow shaft 95 mounted rotatably
on the frame of the folder by means of two bearings 82 and 83. The shaft
95, forming the screw of the reversible screw/nut system 80, carries over
a particular length a high-pitch helical ramp 84, onto which is screwed a
bronze nut 85 forming the nut of the reversible screw/nut system. The gear
87 is keyed to the shaft 95, whereas the gear 86, coaxial with the shaft,
is integral with the nut 85. Screwing the nut 85 on the shaft 95 toward or
away from the frame of the folder produces relative rotation of the gears
86 and 87, thereby making it possible to exert a torque in one direction
or the other so as to rotate one part of the meshing loop in relation to
the other part after the opening of the loop in the region of one or the
other of the two claws.
The nut 85 is screwed on the shaft 95. A central rod 88 passes
concentrically inside the shaft 95, the rod having at one end a
ballbearing 89 for connecting it to the nut 85 and gear 86 assembly, and
at its other end a connection to the rod of an actuating air cylinder 90,
the cylinder of which is connected to the frame of the folder, as shown in
FIG. 9. When the air cylinder 90 exerts a push or pull on the rod 88, the
rod forces the gear 86, via the bearing 89, to slide rotatably on the
shaft 95. If the gear 86 has a left-handed helix and the helical ramp 84
is right-handed, as shown in FIG. 9, the rotational effects are added and
the longitudinal sliding of the gear 86 corresponds to the exertion of a
torque between the gears 86 and 87, the intensity and direction of this
torque depends respectively on the force generated by the air cylinder 90
and on its direction of action, i.e., in the direction of the arrow 125 or
in the opposite direction.
The torque generated at the meshings of the loop is added to the load
moment of the folder when the air cylinder 90 pushes on the system in the
direction of the arrow 125. This, therefore, makes it possible, by feeding
the air cylinder 90 during the operation of the folder, to apply a force,
the effect of which is to cancel any anti-backlash existing in the driving
direction of the gear train. The shaft 95 of the reversible screw/nut
system 80 can thus be subjected to a permanent tractive force, in order to
perform an additional anti-backlash-compensating function during the
continuous operation of the folder. This tractive force can be produced by
means of the air cylinder 90 of the reversible screw/nut system 80, as
just described, but can also be produced by another means, for example, a
compression spring (not shown) bearing on the frame of the folder. In the
latter case, the air cylinder 90 is only used for modification of the
configuration of the folder for the purpose of obtaining either a second
parallel fold or a delta fold.
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