Paper sheet folding device

A paper sheet folding apparatus includes three rotatably mounted folding rollers which cooperate in pairs to provide two folds in a single paper sheet or a packet of paper sheets. A first paper support member on one side of the rollers cooperates with a delivery roller to flex paper into one of the pairs of rollers to provide a first fold in the paper. A second paper support member on the opposite side of the rollers receives the folded paper and cooperates with the first pair of rollers to flex the paper into the second pair of rollers to provide a second fold in the paper. The second pair of rollers then discharges the paper from the apparatus.

BACKGROUND OF THE INVENTION AND PRIOR ART 
The present invention relates to a paper sheet folding device and more 
particularly to such a device adapted to fold a packet of several paper 
sheets at one time. 
A typical construction of such a paper sheet folding device of the prior 
art is disclosed, for example, by Japanese Utility Model Registration No. 
1592186 (Utility Model Publication No. 59-29007). This device comprises a 
paper feeder mechanism, a folding plate provided with an adjustably 
movable stopper and a pair of folding rollers. The paper sheet is fed by 
the paper feeder mechanism to the folding plate in such manner that the 
forward end thereof comes in contact with the stopper of said folding 
plate to be flexed, then the flexed portion of the paper sheet is grasped 
between the folding rollers to fold the paper sheet. 
The device of the prior art as has been described above cannot be used to 
fold a packet of paper sheets because its paper feeder mechanism is not 
adapted to feed the packet of several paper sheets at once and also 
because a folding deviation tends to occur between each pair of adjacent 
paper sheets within each packet when the latter is folded at once. This 
deviation occurs since a location along which each paper sheet is folded 
depends upon factors such as the degree of paper sheet flexure and the 
timing of the paper sheet being grasped by the folding rollers. Thus, this 
device is certainly suitable for continuously handling a plurality of 
paper sheets having the same size one by one, but inconvenient when it is 
desired to fold a packet of paper sheets at once into a predetermined 
size, as when several letter sheets are folded to be inserted into each 
envelope. Accordingly, it has been a usual practice to manually fold each 
packet of letter sheets for insertion into each envelope. However, such a 
manual operation is extremely troublesome and inconvenient in that the 
size of each sheet after being folded cannot be uniform within each 
packet. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to overcome the above-mentioned 
disadvantages of the prior art by the provision of an improved paper sheet 
folding device permitting a packet of several paper sheets to be 
effectively folded at one time into a predetermined size. 
To achieve the object as set forth above, the device constructed in 
accordance with the present invention comprises a support member, a pair 
of folding rollers, delivery means, and a member to drive the delivery 
means. The support member includes an element adapted to position a paper 
sheet or a packet of paper sheets along one end. The folding rollers are 
disposed so that they are closely adjacent to one side of the paper sheet 
or the packet of paper sheets at a position of the fold to be formed. The 
delivery means is disposed on the opposite side to the folding rollers, 
i.e., closely adjacent to the packet on the other side thereof so that 
said delivery means is movable towards the folding rollers. The driving 
member is adapted to drive the delivery means towards a position adjacent 
a line along which the pair of folding rollers come in contact with each 
other. 
With the paper sheet folding device constructed in accordance with the 
present invention as briefly described above, the delivery means is 
actuated to forcibly flex a paper sheet or a packet of paper sheet towards 
the contact line of both folding rollers a portion of the paper sheet or 
packet thus flexed is grasped between the folding rollers so as to fold 
the paper sheet or the packet of paper sheets.

DESCRIPTION OF PREFERRED EMBODIMENT 
Referring to FIG. 1, a support member or folding plate 10 is shown 
consisting of a pair of partitions which define therebetween a thin and 
planar space used to set a paper sheet or a packet of paper sheets. This 
support member 10 is divided into an upper portion and a lower portion at 
a position corresponding to a line along which the packet is folded in a 
manner as will be described later. The division is achieved by a pair of 
openings 12, 14 extending through the associated partitions and defined by 
respective pairs of edges extending perpendicularly to a plane of the 
drawing (longitudinally of folding rollers as will be described later). 
The partitions defining the upper portion of the support member 10 are 
upwardly flared to form an inlet 16 of paper sheets and downwardly 
converged to form an inclined planar region 18. The partitions defining 
the lower portion of the support member 10 are upwardly flared to form a 
guide region 20 and downwardly converged to form an inclined planar region 
22 in alignment with said inclined planar region 18. The lower inclined 
planar region 22 is provided with a threaded stopper 24 which is 
adjustably and slidably fixed in a known manner at a desired position so 
that the forward end of the paper sheet or the packet bears against the 
stopper 24 and thereby the paper sheet or the packet is aligned and 
positioned. This stopper 24 includes a sheet detector element 26 using a 
microswitch or a photosensor. 
Adjacent the opening 12, there are provided outside the support member 10 a 
pair of folding rollers, i.e., a driven roller 30 and a follower roller 
32, which are mounted on axes extending longitudinally of the opening 12, 
respectively, and rotatably driven by drive means associated with said 
axes as will be described later. Adjacent the other opening 14, there is 
provided outside the support member 10 a small roller serving as delivery 
means 34 mounted on a free axis also extending longitudinally of the 
openings 12, 14 for movement towards the folding rollers 30, 32 and 
adapted to be driven by a driving device associated with said axis in the 
direction of said movement. On the side of the folding rollers 30, 32 
opposite to the support member 10, there is provided a downwardly inclined 
folding plate 36 of the arrangement as previously mentioned in connection 
with the prior art and this folding plate 36 also includes a threaded 
stopper 38 which is adapted to be adjustably and slidably fixed at a 
desired position in a known manner. A pair of folding rollers associated 
with the folding plate 36 comprise said driven roller 30 and a follower 
roller 40 operatively associated therewith. 
Referring to FIG. 2, an output shaft of an electric motor (not shown) 
carries a gear 52 coupled via a reduction gear train to a gear 64a which 
is integral with the driven roller 30. The reduction gear train comprises 
a large gear 56 coupled via a timing belt 54 to the output gear 52, a 
small gear 58 coaxial and integral with said large gear 56, and another 
large gear 62 which is coupled via another timing belt 60 to said small 
gear 58 and coaxially integral with said gear 64a. The gear 64a is engaged 
with a gear 66a integral with the follower roller 32, on one side, and 
with a gear 68a integral with the follower roller 40, on the other side. 
The gears 66a, 68a are biased by spring members 70a, 72a, respectively, 
towards the gear 64a. A slot 76a is formed in a housing wall adjacent the 
drive mechanism to support a shaft 74 for the delivery means or small 
roller 34. The slot 76a spans both openings 12, 14 of said support member 
10 as seen in the side view, permitting an operative movement of the shaft 
74 and, therefore, the small roller 34. Adjacent the slot 76a, there is 
provided a lever 80a adapted to rock around its lower shaft 78 which is 
integral with said lever 80a. The lever 80a is driven in a manner as will 
be described later so that said lever 80a may drive the shaft 74 for the 
small roller 34 using a cutaway 82a formed in its upper portion. The lever 
80a is normally biased leftwards as seen in the drawing under an action of 
a spring 86a suspended between a spring hanger 84a mounted on the housing 
wall and an upper end of the lever 80a. 
Referring to FIG. 3, also on this side, a gear 64b integral with the driven 
roller 30 is engaged with gears 66b, 68b which are integral with the 
follower rollers 32, 40, respectively. The gears 66b, 68b are biased 
respectively by springs 70b, 72b into engagement with said gear 64b so as 
to assure a reliable operation of the folder. A slot 76b is formed in the 
housing wall to support the shaft 74 for the small roller 34. A lever 80b 
is provided adjacent this slot 76b. The lever 80b is adapted to rock 
around an integral lower shaft 78. The lever 80b also includes a cutaway 
82b adapted to bear against the shaft 74 under a biasing effect of a 
spring 86b suspended between a spring hanger 84b mounted on the housing 
wall and an upper end of said lever 80b. In regard to these aspects, the 
arrangement of the drive mechanism on this side is in symmetrical 
relationship with that on the side as shown by FIG. 2. 
A small gear 88 is coaxially integral with the gear 64b which is, in turn, 
integral with the driven roller 30. The gear 88 is engaged with a large 
gear 90 located adjacent the center on this side. A cam 92 is coaxially 
integral with the large gear 90 and engaged with a roller 94 projecting 
from the lever 80b. The cam 92 is shown to be in engagement with the 
roller 94 in the largest diameter region (x) of said cam, urging the lever 
80b to its limit position on the right hand in the figure. Therefore, the 
shaft 74 and the small roller 34 are moved from the driven roller 30 under 
the influence of gravity of said small roller 34. When the cam 92 is 
engaged in its smallest diameter region (y) with the roller 94, the lever 
80b is released and rotated leftwards in the drawing under the action of 
the spring 86b and the small roller 34 is urged by the shaft 74 against 
the driven roller 30. While the cam 92 is engaged in its intermediate 
diameter region (z) with the roller 94, the lever 80b is maintained at a 
position slightly rightward with respect to the position at which the 
lever 80b is maintained when the cam 92 is engaged in its smallest 
diameter region (y) with the roller 94. During engagement of the 
intermediate diameter region (z), the small roller 34 is maintained freely 
spaced from the driven roller 30 under the influence of gravity of said 
small roller 34. 
On the opposite side of the lever 80b to the cam 92, there is provided a 
microswitch 96 including a switch pin (not shown) projecting towards the 
lever 80b. The drive motor (not shown) continues to operate independently 
of the position of the microswitch 96 so long as said paper sheet sensor 
element 26 senses the presence of paper sheets. While the element 26 
senses the absence of paper sheets, the drive motor continues to operate 
so long as the switch pin of the microswitch is kept projecting and is 
deenergized upon retraction of said switch pin. 
To perform actual operation of paper sheet folding with the triple folder 
constructed as has been described above, both the stoppers 24, 38 may be 
position-adjusted, if desired, according to the sheet size and the folding 
format in the initial state of the folder. (The respective figures 
correspond to this initial state) Thereafter, a single paper sheet or a 
packet of paper sheets may be introduced through the inlet 16 into the 
support member 10. When the paper sheets bear at their forward ends 
against the stopper 24 and are thereby properly positioned, the sheet 
sensor element 26 senses the presence of the paper sheets, actuating the 
drive motor. Simultaneously, the cam 92 is rotated counterclockwise in the 
drawing to release the lever 80b and, in consequence, said lever 80b and 
the lever 80a are rotated under the effect of the associated springs 86b, 
86a so as to move the shaft 74 for the small roller 34 leftwards in the 
drawing along the slots 76a, 76b. 
Such operation as mentioned above causes, in the central portion of the 
folder, the small roller 34 to move from the opening 14 to the opening 12 
of the support member 10 to forcibly flex the paper sheet or the packet of 
paper sheets within the support member 10 from the rear side of the packet 
towards the pair of folding rollers 30, 32. As a result, a flexed portion 
of the paper sheet or the packet is grasped between the folding rollers 
30, 32 and fed towards the folding plate 36 while the paper sheet or the 
packet is folded between said folding rollers. The upper and lower edges 
of the opening 12 serve as guide elements for effective flexure of the 
paper sheet or the packet. The small roller 34 continues to be rotated 
with the packet held between said small roller 34 and the roller 30 under 
the effect of the springs 86a, 86b, so long as the cam 92 is engaged at 
its smallest diameter region (y) with the roller 94. 
The cam 92 continuously rotates to be engaged at its intermediate diameter 
region (z) with the roller 94 and during such transition the paper sheet 
or the packet of paper sheets has been folded on the side of the folding 
plate 36 in the manner as previously mentioned in connection with the 
paper sheet folding apparatus of prior art. More specifically, the paper 
sheet or the packet of paper sheets introduced into the folding plate 36 
bears at its forward end corresponding to the fold which has been formed 
by the rollers 30, 32 against the stopper 38 provided within the folding 
plate 36. The rollers 30, 32 continue to feed the paper so as to flex the 
paper in the vicinity of the folding rollers 30, 40, and a flexed portion 
of the paper sheet or the packet of paper sheets is grasped between these 
folding rollers 30, 40 to form another fold. Finally, the paper sheet or 
the packet of paper sheets is folded in a desired threefold configuration 
and discharged out of the system. Even when the packet of paper sheets is 
being folded, the occurrence of the folding deviation is negligible, 
since, within the folding plate 36, the packet of paper sheets has already 
been folded on the precedent stage and the fold formed on this precedent 
stage constrains the packet against any significant relative displacement 
of the paper sheets. 
The cam 92 is rotated as the above-mentioned folding process progresses, 
and comes in engagement at its largest diameter region (x) with the roller 
94 again as the paper sheet or the packet of paper sheets is discharged 
out of the system. Thereupon, the lever 80b is rotated to the right and 
back to its initial position as shown in the drawing. In this position, 
the rear side of the lever 80b depresses the switch pin of the microswitch 
96 to deenergize the drive motor. 
Although the support member 10 as well as the folding plate 36 have been 
illustrated to include the respective stoppers 24, 38 in the 
above-mentioned, embodiment, the triple-folder exclusively used to fold 
paper sheet(s) of a fixed size into a predetermined form would require 
neither of these stoppers. The delivery means adapted to forcibly flex 
paper sheet(s) has been illustrated in the form of a small roller, but 
this delivery means may also be in the form of blade-like means having a 
thin edge along its forward end. Furthermore, the starting of the drive 
motor may be achieved not by the paper sheet sensor element 26 but by 
manipulating a separate switch button. In this case, the switch button 
continues to be depressed until rotation of the lever 80b releases the 
switch pin of the microswitch 96 to project and thereby automatically 
actuate the drive motor. 
With the paper sheet folding apparatus according to the present invention, 
the delivery means forcibly flexes paper sheet(s) perpendicularly to the 
plane of paper sheet(s) to start the folding process, so that even a 
packet of several paper sheets can be correctly folded without any 
significant folding deviation.