Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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A Rnife Folder
Description
The present invention refers to paper processing devices in
general and in particular to a knife folder for folding a
sheet material that can, for example, be printed paper.
Knife folders are known from the field of technology. In
such knife folders a sheet feed belt is arranged e.g. hori-
zontally. In side-by-side relation with the sheet feed belt,
a pair of rollers is arranged in such a way that the axes of
rotation of both rollers are located in one plane which ex-
tends parallel to the surface of the sheet feed belt. The
distance of the plane in which the axes of rotation of the
pair of rollers are located is chosen such that a sheet ma-
terial transported by the sheet feed belt is pushed from the
sheet feed belt evenly over the pair of rollers. Normally, a
folding knife is located centrally above the pair of rol-
lers; said folding knife is secured to a lever and it is
adapted to be moved cyclically to a folding position by
means of said lever and a cam disc arrangement. When the
folding knife occupies the folding position, a folding edge,
which is formed at the lower end of said folding knife, is
oriented such that a small distance exists between the plane
defined by the axes of rotation of the pair of rollers and
the folding edge of the folding knife. In addition, the
folding edge is essentially at the same distance from both
axes of rotation. On the side located opposite the sheet
feed belt relative to the pair of rollers, a horizontally
displaceable stop for the sheet material is provided.
In a known knife folder of this kind, the sheet feed belt
transports the sheet material into the folding area. The
horizontal movement of the sheet material is limited by the
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stop for the sheet material, the position of the stop de-
termining the position of the fold on the sheet material.
When the sheet material has reached the folding position,
the folding knife is moved towards the sheet material sub-
stantially at right angles thereto. The folding edge of the
folding knife comes into contact with the sheet material and
presses the contact area, which exists between said sheet
material and said folding edge and which is substantially
linear, between the pair of rollers. This has the effect
that areas of the sheet material which are separated by the
contact area are raised relative to said contact area. The
contact area of the sheet material and of the folding edge
now approaches the plane defined by the axes of rotation of
the two rollers of the pair of rollers.
The combined effect of the two rollers, one of said rollers
being a driven transport roller and the other an idl:ing
counterpressure roller, has the effect that, as soon as the
two rollers take hold of the sheet material in the contact
area, they advance said sheet material in the direction pre-
determined by the direction of movement of the folding knife
into the folding position. The engagement between the pair
of rollers and the sheet material causes the sheet material
to be folded at the point of the contact area due to the
pressure which the pressing roller applies to the transport
roller.
The folding effect existing due to the combined effect of
the transport roller and of the pressing roller takes place
essentially only at the moment at which the contact area of
the sheet material and of the folding knife is located pre-
cisely in the plane defined by the axes of rotation. In view
of the elasticity of the sheet material, the paper fold is
hardly improved still further when the contact area of the
sheet material and of the folding knife is located below the
plane defined by the axes of rotation of the pair of rollers
and when the sheet-material areas bordering on said contact
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area run through said pair of rollers.
When the sheet material has passed the pair of rollers com-
pletely, its direction of movement must be changed by a re-
routing means so as to move said sheet material back into
the plane of a paper processing line comprising the sheet
feed belt and the knife folder as component parts.
For further processing by the paper processing line, it may
be important which side of the sheet material printed e.g.
on one side thereof rests on a sheet-material conveyor belt
and which side faces away from said sheet-material conveyor
belt. If the folded sheet material is inserted e.g. in en-
velopes or the like, the sheet material must first be in-
troduced in the envelope such that the address is directed
downwards, whereupon, after closing of the envelope, said
envelope will have to be turned e.g. for subsequent frank-
ing. There are, however, also cases of use where the sheet
material must have an inverse orientation after folding. In
known knife folders the position of the folded sheet materi-
al in the paper processing line after the knife folder is
determined by the rerouting device and the general conveying
direction of the paper processing line, unless a further de-
vice is provided for a necessary turning of the sheet mate-
rial; such a further device would, however, increase the
investment and the costs.
DE-Al-2 146 013 discloses a means for longitudinally foldig
sheets of paper. A sheet of paper is supplied to a rotating
folding knife in a first direction with the aid of a paper
feed means, the main surfaces of said folding knife extend-
ing also parallel to the first direction and at right angles
to the plane defined by the sheet material supplied. A sheet
that has been prefolded by the combined effect of the fold-
ing knife and an annular groove in a prefolding cylinder is
pushed between two spherical rollers whose axis of rotation
is arranged in a second direction which is perpendicular to
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the first one. These spherical rollers convey the folded
sheet in the first direction to a pair of belts which im-
proves the fold of the sheet of paper.
FR-A-2461671 discloses a folder comprising rotating fold:ing
knives by means of which a sheet material is first prefolded
at right angles to its direction of transport, whereby the
prefolded sheet is engaged by pairs of clamping rollers
which rotate at an oblique angle to the feed direction and
is then drawn away by the rotating folding knives. Also the
pairs of clamping rollers permit only a very brief pressing
together of the fold at the location of their points of con-
tact. The movement of the material to be folded is here
again deflected from a horizontal direction to a conveying
direction that is directed downwards at an oblique angle so
that also this type of folder is difficult to integrate in
paper processing lines.
It is the object of the present invention to provide a knife
folder used for folding a sheet material and permitting, on
the basis of a reduced expenditure, a higher flexibility in
the further processing of the folded sheet material.
This object is achieved by a knife folder for folding a
sheet material according to patent claim 1.
The present invention is based on the finding that, for ob-
taining a fold, it is only necessary that the sheet material
is pressed together as long as possible in comparatively
small areas bordering directly on the fold; in contrast to
the prior art, it is not necessary that the areas located on
both sides of the fold are engaged in their entirety, the
fold itself being, however, pressed only very briefly.
According to the present invention it is also possible to
avoid the necessity of changing the processing plane of the
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sheet material, since the direction of movement of the paper
given by the knife folder according to the present invention
does not correspond to the direction of movement of the
folding knife, but is substantially perpendicular thereto.
Rerouting devices and the like are therefore not necessary
for returning the sheet behind the knife folder into the
processing plane in which it was supplied to said knife
folder. Furthermore, according to one embodiment of the
knife folder according to the present invention, the sheet-
material stream is rerouted at right angles by means of the
knife folder device alone, such rerouting being often advan-
tageous for a paper processing line.
Since the knife folder according to the present invention
causes the sheet material to leave said knife folder in an
upright position and substantially at right angles to the
direction of movement of the folding knife, the position of
the sheet material in the paper processing line behind the
knife folder is freely selectable by turning devices hav:ing
a simple structural design.
In the following, a preferred embodiment of the present :in-
vention will be described in more detail making reference to
the drawings enclosed, in which:
Fig. 1 shows a sectional side view of the knife folder ac-
cording to the present invention, the folding knife
being not at the folding position.
Fig. 2 shows a sectional side view of the knife folder ac-
cording to the present invention, the folding knife
being at the folding position.
Fig. 3 shows a front view of the knife folder according to
the present invention along line A - A' of Fig. 1.
Fig. 1, 2 and 3 show a knife folder 10. A feed means 12
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comprises a drive cylinder 14, an idling cylinder 16" a
transport belt 18 arranged between said drive cylinder 14
and said idling cylinder 16, and pressing cylinders 20a,
20b, 20c.
A lever arrangement 22 is secured to the feed means 12 such
that it is adapted to be rotated about a lever tilting axis.
The lever arrangement 22 is delimited by runners 26a, 26b on
a side located opposite to the pressing cylinders 20 rel-
ative to the lever tilting axis 24, said runners being in
engagement with respective cam discs 28a, 28b.
On a side of the lever arrangement 22 located opposite said
combination of said cam discs 28a, 28b and said runners 26a,
26b relative to the lever tilting axis 24, lever arms 30a,
30b are formed, which are fixedly interconnected by means of
a folding knife holder 32.
Furthermore, a folding knife 34 is connected to the folding
knife holder 32. On the side of the folding knife 34 located
opposite the folding knife holder 32 a folding edge 36 is
formed. The folding knife 34 is provided with recesses 38a,
38b, 38c, 38d, 38e on the side of said folding edge 36, said
recesses being uniformly spaced in the longitudinal direc-
tion of the folding knife 34, which is also referred to as
knife direction.
Below the folding knife 34 there is a folding area 40 which
is defined by a recess in the support 42 for a sheet materi-
al 44 to be folded. The sheet material 44 can be non-folded
or it may e.g. already have a first fold 46. The position of
a second fold 48 (Fig. 2) on said sheet material 44, which
is produced by the knife folder 10 according to the present
invention, is determined by the distance between a stop 50
and a contact line 52 of the folding edge 36 and the sheet
material 44, said stop 50 being attached to the support 42
such that it is horizontally displaceable relative thereto
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according to the embodiment described.
According to the preferred embodiment, a plurality of trans-
port rollers 54a - 54g and a plurality of pressing rollers
are provided on the side of the support 42 located opposite
the sheet material 44. The respective transport rollers 54a
- 54g and the respective pressing rollers 56a - 56g are ro-
tatably supported in a roller support means 58. Transport
roller drive means 60a - 60g are arranged for rotating each
of the transport rollers 54a - 54g about respective axes of
transport roller rotation 62a - 62g. The pressing rollers
56a - 56g are supported such that they are each rotatable
about respective axes of pressing roller rotation 64a - 64g
relative to said transport rollers 54a - 54g. In accordance
with the preferred embodiment of the present invention, the
axes of transport roller rotation 62a - 62g and the axes of
pressing roller rotation 64a - 64g extend all parallel to
one another and at right angles to the roller support means
58 as well as to the support 42. Respective opposed trans-
port rollers 54a - 54g and pressing rollers 56a - 56g define
a pair of conveying rollers, each pressing roller 56a - 56g
being pressed onto the associated transport roller 54a - 54g
of the pair of conveying rollers by a pressing device 66
comprising a spring in accordance with the present embodi-
ment. Each pressing roller of each pair of conveying rollers
can therefore be displaced at right angles to its respective
axis of rotation.
In the case of the embodiment described, the transport rol-
lers 54a - 54g and the pressing rollers 56a - 56g each have
approximately the shape of a truncated cone. As can be seen
from Fig. 1 and Fig. 2, the rollers are composed of a cylin-
drical base which tapers conically towards the folding
knife. This conical taper continues at the respective edges
of the recess in the support 42. This results in a V-shaped
profile of the folding area 40. In other words, this
V-shaped profile of the folding area 40 is defined by the
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cooperation of a pair of conveying rollers, said V-shaped
profile being continued by the recess in said support 42.
As can be seen in Fig. 3, the recesses 38a - 38e, which are
provided in the folding knife 34, are each centered relative
to the axes of transport roller rotation 62a - 62g in the
knife direction. Cylindrical pressure rollers 68a, 68b, 68c,
68d (68c, 68d not shown) are arranged in pairs in side-by-
side relation with the respective outermost pair of convey-
ing rollers 54a, 56a and 54g, 56g. The way in which the cy-
lindrical pressure rollers, which are arranged in pairs, are
oriented relative to one another corresponds to the orienta-
tion of the pairs of conveying rollers. Each of the cylin-
drical pressure rollers 68a, 68b is rotated about a respec-
tive axis of rotation 72a, 72b of said cylindrical pressure
rollers by a drive means 70a, 70b for said cylindrical pres-
sure rollers. The cylindrical pressure rollers 68c, 68d,
which are not shown, are pretensioned towards the respective
cylindrical pressure rollers 68a, 68b.
In the following, the mode of operation of a preferred em-
bodiment of the knife folder 10 according to the present in-
vention will be explained in detail.
When the sheet material 44, which can be folded (e.g. the
first fold 46) or non-folded, has been transported with the
aid of the feed means 12 over the folding area 40 in such a
way that said sheet material 44 is in contact with the stop
50, the folding operation takes place.
Fig. 1 shows the condition of a preferred embodiment of the
knife folder 10 according to the present invention immedi-
ately before the folding operation begins. The lever ar-
rangement 22 and the folding knife 34 connected thereto via
the folding-knife holder 32 are located at their position of
maximum deflection relative to the support 42. This maximum
deflection is given by the size of a cam provided at a spe-
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cific peripheral section of the cam discs 28a, 28b. A joint
rotation of the cam discs 28a, 28b causes the runners 2~a,
26b to rotate as well, in the opposite direction of rota-
tion, and this has the effect that the fixedly connected
lever arms 30, 3Ob, which are rotatably supported about the
lever tilting axis 24, descend into the folding area 40.
This has the effect that the folding edge 36 of the folding
knife 34 comes into contact with the sheet material 44 along
the contact line 52. When the rotation of the cam discs 28a,
28b continues, the folding edge presses the sheet material
deeper an deeper into the folding area, whereby the areas of
the sheet material located outside of the folding area are
raised to a V-shape, as can be seen from Fig. 2.
When the cam disc 28a, 28b rotates still further, the sheet
will be pressed between the respective pairs of conveying
rollers 54a, 56a - 54g, 56g by the folding knife 34, as can
be seen in Fig. 2. The recesses 38a - 38e prevent the fold-
ing knife 34 from being engaged by the pairs of conveying
rollers at this position, which is referred to as folding
position. The areas of the folding edge 36 located between
said recesses 38a - 38e cause the paper to be pressed be-
tween the pairs of conveying rollers against the biasing
force exerted by the respective pressing devices (not
shown). The sheet material 44 to be folded is now fixedly
engaged by the individual pairs of conveying rollers due to
the biasing force exerted by the individual pressing de-
vices. Hence, the lever arrangement 22 can be raised again
without disengaging the sheet material from the pair of con-
veying rollers. The folding knife 34 is thus removed from
the folding area 40, whereupon a new folding cycle can
begin.
Depending on the direction of rotation of the transport rol-
ler drive means 60a - 60g, the sheet material, which has
been engaged by the pairs of conveying rollers and raised to
a V-shape, can, in relation to Fig. 1, laterally be removed
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-- 10 --
from the folding area in the direction of the cylindrical
pressure roller 68a or in the direction of the cylindrical
pressure roller 68b. Due to this lateral removal from the
folding area 40, the second fold 48, which was so to speak
only prepared at the contact lines of the individual trans-
port rollers 54a - 54g and the individual pressing rollers
56a - 56g at the moment at which the folding knife 34 was
removed from the folding area 40, is fully executed by the
individual pairs of conveying rollers. For improving the
quality of the now fully executed second fold 48 still fur-
ther, the sheet runs through the pair of cylindrical pres-
sure rollers 68a, 68b, which is arranged on the side at
which the folded sheet material 44 is transported away from
the folding area.
For further processing the folded sheet material 44 in a
paper processing line - the knife folder 10 according to
the present invention being part of such a paper processing
line -- it turns out to be advantageous that the sheet oc-
cupies a raised, substantially vertical position, whereby
said sheet can be laid, with the aid of simple means, on its
first e.g. printed side or on its second e.g. non-printed
side, as demanded by subsequent sheet material processing.
Summarizing, it can be stated that the knife folder 10 ac-
cording to the present invention carries out in a single de-
vice not only the folding function but also the deflection
at right angles and the raising of the sheet material.
Deviating from the embodiment shown, a plurality of differ-
ent modifications of the knife folder 10 according to the
present invention exists.
It is, for example, possible to omit the feed means 12,
since the sheet material 44 can be fed directly into the
knife folder 10 by a device preceding the knife folder 10 in
the paper processing line. In this case, it will be neces-
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sary to fix the lever arrangement 22 in some other way and
to synchronize it with the sheet material feed rate.
Furthermore, it is not necessary that the knife folder is
oriented essentially horizontally. It can, for example, also
be inclined in a certain manner, in accordance with the re-
quirements of a specific case of use.
The folding knife 34 need not be suspended from the lever
arrangement 22, but it can be suspended in some other way
independently of the feed means 12 and it can hit the sheet
material 44 at an arbitrary angle which is not parallel to
said sheet material. In addition, it is of secondary im-
portance to the present invention whether the recesses ex-
tend from the folding edge 36 to the folding knife holder
32, or whether they are not provided at all, as long as the
surfaces of the transport rollers 54a - 54g or of the pres-
sing rollers 56a - 56g are of such a nature that the sheet
material 44 remains in engagement with the pair of conveying
rollers when the folding knife 34 is moved away from the
folding area 40.
Although a plurality of pairs of conveying rollers is shown,
one pair of conveying rollers in combination with cylin-
drical pressure rollers 68a, 68b will suffice to produce a
continuous fold of the sheet material 44. It is also pos-
sible to omit the cylindrical pressure rollers 68a, 68b be-
cause the continuous fold is already produced by the pairs
of conveying rollers. In addition, it is not necessary that
the sheet material feed means is implemented in the form of
pairs of conveying rollers, since it is also possible to
provide a continuous, elastic conveyor belt whose surface,
which comes into contact with the sheet material 44, can be
implemented such that it remains in engagement with the
sheet material 44 when the folding knife 34 is removed from
the folding area 40. The described reduction of size of the
diameter of the transport rollers 54a - 54g and of the pres-
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sing rollers 56a - 56g existing in the direction of the sup-
port 42 need not be linear, but the cross-section can also
be sph.erical, parabolic or it can be reduced continuously in
some other way.
Finally, neither the support 42 nor the stop 50, which have
been described with regard to a preferred embodiment of the
knife folder 10, are absolutely necessary, since the sheet
material 44 can also be placed at a specific position di-
rectly above the pairs of conveying rollers by means of a
defined kinetic energy which the sheet material received
from the feed means.
