Device for cutting stacked product in sheet form

The invention relates to a device for cutting stacked product (25) in sheet form having a table (12), the surface of which has an operating area, above which there is a cutting blade (2) and a pressing beam (3), behind it a feed area to receive the product to be cut and in front of it an output area to receive the cut product, and having a forward feed apparatus for the product to be cut. In order to avoid strenuous mechanical and ergonomically harmful work when turning the product to be cut, in particular in conjunction with the edge trimming of the product, it is proposed according to the invention to provide in the region of the feed area a gripper system (29) for turning the product to be cut in the plane of the table surface.

The invention relates to a device for cutting stacked product in sheet form 
having a table, the surface of which has an operating area, above which 
there is a cutting blade and a pressing beam, behind it a feed area to 
receive the product to be cut and in front of it an output area to receive 
the cut product, and having a forward feed apparatus for the product to be 
cut. 
A device of this type is known, for example, from German 
Offenlegungsschrift 3,101,911. In the latter, during edge trimming the 
stack is customarily pulled onto the output area after an edge cut by the 
operator present in the region of the output area, is turned by 90.degree. 
there, is pushed back onto the feed area and there is placed in a defined 
position below the cutting blade by means of the forward feed apparatus so 
that the next edge cut can take place, following which appropriate edge 
cuts are made until, finally, all the edges of the stack have been 
trimmed. An operating mode of this type requires strenuous manual work, 
the sequence of movements being extremely unfavourable from an ergonomic 
viewpoint since the operator has to pull the heavy product towards him and 
then turn it outside the usual arm reach envelope, that is to say with the 
trunk bent forwards. This applies not only for the edge cuts described but 
in general when it is necessary for the product to be cut to be turned 
within the region of the feed area. 
The object of the present invention is to develop a device of the type 
mentioned to the extent that strenuous manual and ergonomically harmful 
work is avoided when turning the product to be cut, in particular in 
conjunction with the edge trimming of the product. 
The object is achieved in that a gripper system is provided in the region 
of the feed area for turning the product to be cut in the plane of the 
table surface. The gripper system enables any work arising in the region 
of the feed area to be carried out fully automatically. For example, by 
means of the gripper system the product to be cut can be turned in 
conjunction with edge trimming, moreover the product to be cut can be 
pulled back in the direction of the forward feed unit and also advanced in 
the direction of the cutting blade by means of the gripper system, which 
results in the ordered positioning of the stack to be cut being simplified 
substantially. In this case, an air jet system can additionally be 
provided in the table, in particular in the region of the feed area, to 
reduce the displacement forces. 
The gripper system itself should expediently have at least one pair of 
gripper tongs which is displaceable parallel and perpendicular to the 
table surface, with the gripping plane oriented parallel to the table 
surface. The gripper tongs thus grip the stack to be cut laterally, when 
using two pairs of gripper tongs they can grip the stack on one side or on 
opposite sides. 
According to a particular embodiment of the invention, provision is made 
for the device to have a first support projecting over the feed area, the 
free end of which support receives a second support which can be swivelled 
parallel to the table surface and which, in turn, receives the gripper 
tongs in a manner so as to be displaceable perpendicular to the table 
surface. The first support expediently extends approximately to the centre 
of the feed area so that the second support only has to be slightly longer 
than half the length of the longitudinal extent of the feed area. In this 
context, it is considered to be advantageous if the second support is 
constructed so as to be variable in length, by which means the 
displacement times of the forward feed apparatus of the product to be cut 
can be reduced since the second support can position the stack nearer to 
the cutting blade during the turning of the stack and during a 
superimposed retraction movement of the support and a following movement 
of the forward feed apparatus. 
In guides in the region of its free end, the second support should receive 
a gripper support which is perpendicular to said second support, is 
displaceable parallel to the table surface and in which a lifting element 
is mounted, to which lifting element the gripper tongs are connected. Due 
to the displaceable mounting of the gripper support, the gripper tongs can 
grip the stack to be cut at different intervals from the operating area, 
in particular at the centre of the stack side to be gripped. In addition, 
it is considered to be advantageous if two pairs of gripper tongs are 
connected to the gripper support, which gripper tongs are spaced apart and 
do not grip the stack in the centre of the stack side, but further towards 
the outside. The lifting element assigned to the respective gripper tongs 
for lowering and raising the gripper tongs should advantageously be 
constructed as a lifting cylinder which is charged pneumatically or 
hydraulically. In addition, it is, of course, also possible to displace 
the gripper tongs by means of a spindle or the like. 
A preferred embodiment of the invention provides for the projecting support 
to be stationary. According to a further embodiment, provision is made for 
the projecting support to be displaceable parallel to the longitudinal 
extension of the cutting blade and the pressing beam. The projecting 
support can, for example, be connected to a stand receiving the cutting 
blade and the pressing beam. However, it is also possible instead for the 
projecting support to be connected to a stand arranged behind or next to 
the output area. Particularly in that case when the support is arranged 
behind the output area, the pair or pairs of gripper tongs can take over 
the function of the forward feed apparatus. Moreover, the first and the 
second supports can form a knuckle joint, to the free end of which that 
gripper support is preferably connected which has the two pairs of gripper 
tongs which are displaceable perpendicular to the table surface. The 
gripper system thus not only receives the function of turning the stack, 
but also of advancing it, and it is even possible to transfer the product 
to be cut from peripheral equipment to the device by means of the gripper 
system. If the grippers have mobility relative to one another, the gripper 
system can additionally receive the function of a swivelling saddle which 
balances out the angular position tolerances of the stack. 
Each pair of gripper tongs expediently has a lower gripper jaw which is 
stationary in relation to the gripper tongs and an upper gripper jaw which 
is displaceable in relation to said gripper tongs perpendicular to the 
table surface by means of a lifting element, in particular a lifting 
cylinder. In order to ensure that the product to be cut can be gripped 
securely by means of the gripper tongs, the table should have in the feed 
area a trough to receive the lower gripper jaw. Beside this or 
additionally the table can have in the feed area lifting cylinders mounted 
in said feed area, the piston rods of which can be extended from the table 
and, with an appropriate positioning of the stack to be cut, thus lift 
said stack in the edge region so that the lower gripper jaw can be moved 
below the stack. 
A particular embodiment of the invention finally provides for the table to 
be fitted with at least one lateral stop, which can be lowered or folded 
below the table surface, for aligning the product to be cut. It is thus 
possible even to turn such stacks on the feed area of the device, the 
diagonal dimension of which stacks is greater than the width of the feed 
area and consequently, during turning, protrude over the lateral boundary 
of the feed area in the region of their corner. 
Further features of the invention are illustrated in the description of the 
figures and in the subclaims, it being noted that all the individual 
features and all the combinations of individual features are essential to 
the invention.

The device described in the figures refers to a paper-cutting machine 
forming one structural unit. As described with regard to the first 
embodiment according to FIGS. 1 to 4, this has in a known manner a table 
12, the surface of which has an operating area 12a, above which there is a 
cutting blade 2 and a pressing beam 3, behind that a feed area 12b to 
receive the product 25 or 25' to be cut and in front an output area 12c to 
receive the cut product (not shown in detail). Serving for the 
displacement of the product to be cut is a spindle-driven forward feed 
saddle 13 which can be displaced in the longitudinal extension of the 
table 12 over the feed area 12b. Additionally, the figures show the 
machine stand 11 of the paper-cutting machine, the portal 11a of which is 
arranged above the table 12 and receives on its underside the cutting 
blade 2 and the pressing beam 3. Reference numeral 4 denotes an electric 
motor flanged onto the machine stand 11 for driving the paper-cutting 
machine 1. 
As can be seen from the illustration of FIGS. 1 to 3, a gripper system 29 
is connected to the portal 11a. In detail, a projecting first support 14 
is flanged onto the portal 11a on the side facing the feed area 12b. Said 
support extends perpendicular to the portal 11a in the plane of symmetry 5 
of the table 12 almost up to the table centre. The free end of the support 
14 is fitted with brackets 14 which are arranged parallel to each other 
and are penetrated by a bolt 6 oriented perpendicular to the feed area 
12b. A second support 15 can be swivelled about the bolt 6 between the 
brackets 14, which support can be retained via retaining means (not shown 
in detail) in a first position shown in FIGS. 1 to 3 parallel to the 
portal 11a and in a second position swivelled away from the portal 11a at 
a right-angle to said first position (double arrow A in FIG. 1). The 
support 15 is of two-part construction, a first tubular support element 
15a is connected to the free end of the support 14 and fitted with guide 
rollers 15b for a further support element 15c which is displaceable in the 
longitudinal direction of the support element 15a. Engaging on the support 
14 and on the support element 15a is a pneumatically driven swivel 
cylinder 7, by means of which the support element 15a can be swivelled 
from the position at right-angles to the support 14 into the extended 
position. Arranged between the support element 15a and the support element 
15c is a pneumatically acting cylinder 16 which serves for extending and 
retracting the support element 15c. The structural dimensions relating to 
the second support 15c are such that it is possible to retract it as far 
as possible, but on the other hand also to extend it so far that it 
projects over the lateral edge 12d of the table 12, and extends, on the 
other hand, up to the forward feed saddle 13 in the extended position. 
The support element 15c has in the region of its free end upper and lower 
guides 18 extending perpendicular to the longitudinal extension of said 
support element and parallel to the feed area 12b, in which guides a 
gripper support plate 17 is displaceably mounted. The displacement of the 
gripper support plate 17 takes place via a further pneumatic cylinder 8 
which, on the one hand, engages on the support element 15c and, on the 
other hand, on a bearing ring 9 of the gripper support plate 17. The 
length of the guides 18 is dimensioned such that the gripper support 
plates 17--in relation to the illustration of FIG. 1--can be moved between 
a position adjacent to the portal 11a and a position symmetrical to the 
centre of the feed area. Connected to the gripper support plate 17 are two 
spaced-apart gripper receptacles 10. Each has a receptacle extending 
perpendicular to the feed area 12b, which receptacle is penetrated by a 
guide rod 21 which, in turn, receives at its lower end a pair of gripper 
tongs 22. Mounted, furthermore, in each gripper receptacle 10 is a 
pneumatic lifting cylinder 19 which engages on the gripper tongs 22. The 
gripper tongs 22 have a lower gripper jaw 22a which is fixedly connected 
to the lower end of the guide rod 21 and the piston rod 19a of the lifting 
cylinder 19. An upper pair of gripper tongs 22b is provided with two 
boreholes (not shown in detail) which are penetrated in a guiding manner 
by the guide rod 21 and the piston rod 19a, a further pneumatic lifting 
cylinder 20, connected to the guide rod 21 above the upper gripper jaw 
22b, engages with its piston rod 20a on the upper gripper jaw 22b . Thus 
the lifting cylinder 20 permits the upper gripper jaw 22b to move in 
relation to the relatively stationary lower gripper jaw 22a and thus to 
grip and release the product 25 to be cut. 
It can additionally be seen from FIGS. 1 and 2 that the paper-cutting 
machine 1 has in the region of the left lateral edge 12d of the feed area 
12b a lowerable lateral ruler 23. Mounted below the table 12 adjacent to 
this lateral ruler 23 are several lifting cylinders 24 each at the same 
distance from the lateral edge 12d, the piston rods 24a of which lifting 
cylinders penetrate passage boreholes (not denoted in detail) in the feed 
area 12b of the table 12 and, when the piston rods 24a are extended, as is 
shown in particular in FIG. 2, project beyond the surface of the table 12. 
The device described thus far operates as follows: after edge trimming of 
the narrow edge 25a of the product 25 to be cut, the narrow edge 25a is 
situated in the cutting plane 27 of the blade and the longitudinal edge 
25b of the product 25 to be cut rests against the lateral ruler 23. The 
forward feed saddle 13 is moved into the retracted end position shown in 
FIG. 1, then the piston rods 24a of the lifting cylinders 24 are extended 
to the extent that the product 25 to be cut can be gripped from below by 
means of the lower gripper jaw 22a. Firstly the two grippers 22 are moved 
so far downwards until the lower gripper jaw 22 is on the same level as 
the gap between the product 25 to be cut and the table 12. The upper 
gripper jaw 22b has been moved away from the lower gripper jaw 22a to 
correspond to the stack thickness. Then the support element 15c is 
retracted so far into the support element 15a until both pairs of gripper 
tongs 22 completely enclose the stack 25 to be cut. Depending on the 
length of the stack to be cut, it may be necessary to displace the 
grippers along the guides 18 prior to introduction into the stack so that 
it is ensured that the gripper tongs 22 are positioned symmetrically to 
the assigned axis of symmetry of the stack 25 to be cut. After closing the 
gripper tongs 22 by lowering the gripper jaw 22b onto the stack 25, the 
piston rods 24a of the lifting cylinders 24 are retracted. In order to 
provide the required swivelling space for the product 25 to be cut, the 
support element 15c is then partially retracted into the support element 
15a so that the stack 25 comes to rest approximately symmetrically to the 
longitudinal axis of the table. Then the retaining mechanism situated in 
the region of the bolt 6 is released and the support 15 is swivelled by 
90.degree., air jets (not explained in detail) arranged in the table in 
the region of the feed area thereby reducing the friction between the 
stack and the table. In this position, the support 15 forms a straight 
line with the support 14, in which line the two supports 14 and 15 are 
again engaged with each other. During the swivel movement of the support 
15, the extension of the support element 15c out of the support element 
15a and the moving of the gripper support plate 17 in the guides 18 
already expediently take place so that the product to be cut comes to rest 
adjacent to the lateral edge 12d of the table on completion of the swivel 
movement and the longitudinal side 25c is positioned on the feed area 12b 
at a slight distance from the cutting plane 27 of the blade. The lowerable 
lateral ruler 23 is then again transferred into the extended position 
shown in FIGS. 2 and 3 and the now turned stack 25' of the product to be 
cut is placed by slight moving of the gripper support plate 17 in the 
guides completely against the lateral stop. After release, the gripper 
tongs 22 are moved out of the stack 25' and the support 15 is again 
swivelled into the position shown in FIG. 1. By means of the forward feed 
saddle 13, the product 25' to be cut can then be advanced under the 
cutting blade 2 up to the desired cutting plane. After pressing down by 
the pressing beam 3, the cut then takes place. The next edge trimming 
follows in the sequence of operation described. The structure described 
above of the device according to the invention not only permits turning, 
in particular by a right-angle, of the product 25 or 25' to be cut, but 
the gripper system can also take over the function of the forward feed 
saddle. Namely, in the extended position of supports 14 and 15, the 
gripper tongs 22 grip the product 25 or 25' to be cut at the rear edge and 
the product to be cut can thus be advanced by retraction of the support 
element 15c in to the support element 15a, or withdrawn in the case of an 
opposite movement. Moreover, it is, of course, possible in an appropriate 
constructional development of the device not only to swivel the support 15 
by an angle of 90.degree. out of the position shown in FIG. 1, but also by 
an angle of 180.degree. so that further edge trimming can be undertaken 
without the gripper tongs 22 having to be released. 
FIG. 4 shows a slight modification of the paper-cutting machine described 
thus far in FIGS. 1 to 3. In the latter, the support 14 is mounted so as 
to be displaceable parallel to the longitudinal extension of the cutting 
blade 2 and pressing beam 3 in guides 26 extending over the entire length 
of the portal 11a. The support 14 is displaced by means of a pneumatic 
cylinder which is not visible in this view. The displaceability of the 
support allows, for example, a stack to be removed from peripheral 
equipment or discharged to such equipment. 
FIGS. 5 and 6 show principle illustrations of further embodiments of a 
paper-cutting machine 1 having a table subdivided correspondingly into 
operating area 12a, feed area 12b and output area 12c as well as the 
cutting plane 27 of the blade. Provided parallel to the cutting plane 27 
of the blade behind the table is a guide 28, in which a similar gripper 
system 29 is displaceable. A base plate 30 of the gripper system is 
displaceable in the guide 28, a first support 31 directed towards the 
cutting plane 27 of the blade is connected fixedly to said base plate. In 
accordance with the function of supports 14 and 15 according to the first 
embodiment, a second support 32 is mounted displaceably in the support 31. 
The free end of the support 32 receives a gripper support plate 33 which 
can be swivelled about an axle 34 orientated perpendicular to the feed 
area 12b. The power means to move the base plate 30, to extend the support 
32 and to swivel the gripper support plate 33 are not explained in the 
figures. The gripper support plate 33 corresponds in its structure and its 
function to the gripper support plate 17 according to the embodiment 
described previously, two pairs of gripper tongs being mounted in said 
gripper support plate so as to be displaceable parallel to the plane of 
the feed area 12b and perpendicular to the latter corresponding to the 
embodiment mentioned. In the embodiment described in FIG. 5, after 
gripping the turning of the product 25 to be cut takes place by a 
superimposition of the displacing movement of the base plate 30 with the 
extension or retraction movement of the support 32 and the swivel movement 
of the gripper support plate 33. I shows the product 25 to be cut which 
has been gripped laterally with the support 32 extended and the gripper 
support plate 33 lying flush with the support 32. II shows an intermediate 
position with partially retracted support 32 and gripper support plate 33 
swivelled by an angle of 45.degree. in relation to the extended starting 
situation. III shows the product 25' to be cut turned by 90.degree. with 
the support 32 largely retracted and the gripper support plate 33 
swivelled by 90.degree.. The retraction movement of the support 32 and the 
swivel movement of the gripper support plate 33 between operating 
conditions I and III is superimposed by a displacing movement of the base 
plate 30. After reaching the turned position, the product 25' to be cut 
can be placed by defined movement of the base plate 30 and the support 32 
against the assigned lateral ruler 23 next to the cutting plane 27 of the 
blade. The defined forward feed of the product 25' to be cut to the 
separation point can then take place after the gripper system 29 has been 
moved out of the region of the forward feed saddle 13 by the latter. As 
described concerning the previous embodiment, the gripper system 29 can 
replace the forward feed saddle 13 and thus serve for the displacement of 
the product to be cut, by the swivellable mounting of the gripper support 
plate 33 the latter can additionally execute the functions of a swivelling 
saddle. 
FIG. 6 explains with reference to a further embodiment that the telescopic 
supports 31 and 32 described concerning the embodiment according to FIG. 5 
can also be replaced by a two-part knuckle joint 35. For example, a lever 
part 35a can be swivelled about an axle 36 of the displaceable base plate 
30, which axle is oriented perpendicular to the table 12 and arranged 
behind the feed area 12b. With the end of the lever part 35a facing away 
from the axle 36, a lever part 35b can be swivelled about an axle 37 
arranged parallel to the axle 36, the end of the level part 35b facing 
said axle in turn receives the gripper support plate 33 which can be 
swivelled about an axle 34 arranged parallel to the axle 37. In accordance 
with the embodiment according to FIG. 5, the gripper support plate 33 in 
turn receives two pairs of gripper tongs which are displaceable in the 
plane of the table and perpendicular thereto. The power means for 
swivelling the knuckle joint 35 in total and additionally the lever parts 
35a and 35b as well as the gripper support plate 33 are not explained in 
the drawing of FIG. 6. I shows the product 25 to be cut which is gripped 
at the side with knuckle joint 35 extended. II shows the stack to be cut 
in a partially turned position, in which the knuckle joint 35 is partially 
bent and the gripper support plate 33 is swivelled out of the starting 
position by an angle of 45.degree.. III shows a further bent knuckle joint 
35 with the gripper support plate 33 swivelled by 90.degree. out of the 
starting position and thus the product 25' to be cut turned by 90.degree.. 
During the turning of the product to be cut, the swivel movement of the 
gripper support plate 33 and the knuckle joint 35 can be superimposed by a 
displacement movement of the base plate 30 in order to place the product 
25' to be cut against a lateral stop again. Within the framework of this 
embodiment it is conceivable to construct the lever parts 35a/35b so as 
to be variable in length, the variation in length in turn taking place via 
power means. 
FIG. 7 shows a variant of a gripper system constructed as a clamping beam 
40. The clamping beam 40 has a first beam part 40a which is attached to 
the gripper support plates 17 and 33 described above and in which a 
further beam part 40b is mounted so as to be displaceable in the 
longitudinal direction via adjustment means (not shown in detail). Two 
downwardly directed brackets 38 of the clamping beam 40 are provided with 
the gripper tongs 22 described above. The two pairs of gripper tongs 22 
are directed towards each other and thus permit gripping on both sides of 
the product 25 to be cut. FIG. 7 shows, on the right, a lifting cylinder 
24 with an extended piston rod 24a and, on the left, the feed area 12b of 
the table 12 is fitted instead for another variant with a trough region 39 
into which the lower gripper jaw 22a can be inserted so that separate 
lifting of the product 25 to be cut in the gripper region is not required.