Gripper cylinder in a folding apparatus

A gripper cylinder for a folding apparatus, the gripper cylinder having a cylinder shaft on which a cylinder body is mounted and at least two gripper stations mounted to the cylinder body. The gripper stations include grippers and corresponding gripper bases. An adjustment mechanism is provided for adjusting the distance between each gripper and its corresponding gripper base to correspond to the thickness of a product to be gripped. The gripper mechanism is operative to simultaneously adjust all of the gripper stations.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a gripper cylinder for a folding apparatus with 
adjusting means for adjusting the distance between the grippers and the 
gripper bases corresponding to the thickness of the products to be 
gripped. 
2. Description of the Prior Art 
A gripper cylinder is part of a folding apparatus for cutting and folding a 
paper web and is known, e.g., from EP 0 531 648 A1. The folding apparatus 
described in this reference has a gripper cylinder and folding blade 
cylinder. In order to grip products of different thickness with a gripper 
cylinder of this type, the springing action of the gripper must be 
utilized. Sometimes, it is also attempted to adjust the supports with 
which the grippers cooperate, i.e. the gripper bases, individually at 
every gripping station. Further, the grippers are also adjusted 
individually for different product thicknesses by means of adjusting 
screws. This construction, however, has the disadvantage of being rather 
costly. Also, under certain circumstances, marks may appear on the 
products when spring-loaded grippers press too heavily against the paper. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present innovation to improve a gripper 
cylinder so that the distances between the grippers and the gripper bases 
are adapted to the product thickness in a simple manner so that products 
can be transported further without damage or marks regardless of their 
thickness. 
Pursuant to this object, and others which will become apparent hereafter, 
one aspect of the present invention resides in a gripper cylinder having a 
cylinder body mounted on a cylinder shaft. At least two gripper stations 
are mounted on the cylinder body and include grippers with corresponding 
gripper bases. Adjusting means are provided for adjusting the distance 
between each gripper and its corresponding gripper base so that the 
distance corresponds to the thickness of the product to be gripped. The 
adjusting means is operative to simultaneously adjust all the gripper 
stations. 
Pursuant to a further embodiment of the invention the adjusting means is 
operative to adjust the gripper bases. 
In still another embodiment the gripper bases are formed by rollers which 
have a periphery formed by a plurality of surfaces at different distances 
from the center of the roller. It is also possible for the rollers to be 
supported eccentrically on the cylinder body. The outer surface of the 
rollers can also have a non-circular cross-section, such as an elliptical 
cross-section. 
Still an additional embodiment of the invention has means for moving the 
gripper disks. The moving means includes a rotatable disk provided on at 
least one end of the cylinder body, which disk is rotatable by helical 
gear wheels. The rotation of the disk causes the rollers which form the 
gripper bases to rotate. 
In yet another embodiment the disk can be adjusted manually by utilizing a 
threaded spindle which is connected to the disk and further connected to a 
member fixed to the shaft of the cylinder. Thus, rotation of the spindle 
causes the disk to be moved relative to the fixed member. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of the disclosure. For a better understanding of the invention, its 
operating advantages, and specific objects attained by its use, reference 
should be had to the drawing and descriptive matter in which there are 
illustrated and described preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
As shown in FIG. 1, a gripper cylinder has a cylinder body 1 as a support 
or base for gripper stations 2, the illustrated gripper cylinder having 
three gripper stations, for example. When the gripper cylinder is 
constructed as a gripper cylinder and folding-blade cylinder, it also has 
another cylinder body which supports the folding blades. Each gripper 
station 2 has one or more grippers 3 (compare FIG. 2a) which press the 
products against the gripper base. In a first embodiment of the invention, 
the gripper bases are constructed as rotatably supported rollers 4 (FIG. 
1, 2a-c). Every roller 4 has, at its circumference, surfaces 40, 41, 42, . 
. . (FIGS. 2a-c) at different distances from the center axis of the roller 
4. A different one of the surfaces 40, 41, 42, . . . can be selected by 
rotating the roller 4. Accordingly, the distance between the surface 40, 
41, 42, . . . and the gripper 3 can be suitably adapted to the product 
thickness. 
The rollers 4 are rotated by means of a disk 6 which is arranged on the 
cylinder shaft 5 (FIG. 1) so as to be rotatable. The disk 6 is connected 
with an element 7 which is arranged on the roller 4 in a stationary 
manner. This element 7 and the disk 6 are preferably constructed as 
toothed wheels. The disk 6 itself is adjusted relative to the cylinder 
body 1 and the shaft 5 by means of opposed helical toothed gear wheels 8. 
Instead of individual surfaces 40, 41, 42, . . . , the roller 4 can also 
have a continuous surface with an elliptical cross section or an 
eccentrically supported surface with a circular cross section. The roller 
4 as shown in FIG. 2c also advantageously has resilient, e.g., rubber, 
inserts 9 on its surfaces 40, 41, 42, . . . or on its continuous surface. 
In another embodiment of the invention, continuously adjustable gripper 
bases 10 (FIGS. 3, 4) constructed as blocks are provided instead of the 
rollers 4. This gripper base 10 is arranged in a slide guide or 
straight-edge guide 11 that extends radially to the center of the 
cylinder. Toothed segments 12 are arranged at the end sides of the 
cylinder body 1 for adjusting the gripper base 10 in the direction of 
arrow A. These toothed segments 12 mesh with toothed wheels 14 arranged at 
both sides on a shaft 13 supported in the interior of the gripper base 10. 
One of the toothed wheels 14 is connected with a lever 15 in a stationary 
manner on one end of the cylinder. This lever 15 is in turn articulated at 
a movable lever 16. The lever 16 is movably connected with the disk 6 
which is arranged so as to be rotatable on the cylinder shaft 5. The 
levers 15, 16 and accordingly the toothed wheel 14 are adjusted by 
rotating the disk 6 in the direction of arrow B. 
In a further embodiment of the invention, the gripper base 10 (FIG. 5) is 
supported in the straight-edge guide 11 at the end sides of the gripper 
cylinder respectively via two levers 17, 18 at articulation points a, b, 
c. The levers 17, 18 are connected with another lever 180 at articulation 
point b, this lever 180 being movably connected with a disk 19 or 20 (FIG. 
6) which is rotatably arranged on the cylinder shaft 5. The disks 19, 20 
are either rigidly connected with one another via a connecting member 21 
so that the rotating movement transmitted via the helical toothed wheels 8 
is adjusted parallel to the axis, or the disks 19, 20 (FIG. 7) are 
adjustable separately, e.g., via opposed helical toothed gear wheels 8'. 
This enables an additional one-sided adjustment which is especially 
necessary when the products to be gripped have different thicknesses at 
the two end sides, e.g., as a result of a folded spine. 
Instead of adjusting a roller 4 which serves as gripper base 10 or 
adjusting the gripper base 10, it is also possible to adjust the grippers 
3 either by themselves or in combination with the rollers 4 or the gripper 
bases 10 so as to adapt their spacing to the products. For this purpose, 
the grippers 3, together with the gripper spindle 22 (FIG. 8) to which 
they are fastened, are rotatably supported in a support 23 in an eccentric 
manner. A lever 24 is secured to the support 23 at one side of the 
cylinder. Another lever 25 is rotatably supported at the lever 24, and is 
secured to a disk 26 (FIG. 9) which is rotatably supported on the cylinder 
shaft 5. The disk 26 is adjusted in turn by means of the toothed wheels 8, 
e.g., by an angle .beta. (FIG. 8). This enables a maximum adjustment of 
the position of the gripper 3 by a distance d. 
As is shown in FIG. 10 with reference to the disk 26, the disk 6, 19 or 26 
can also be adjusted manually relative to the cylinder shaft 5 by means of 
a threaded spindle 27 which is rotatably arranged in the disk 26 and a 
segment 28 which is arranged on the cylinder shaft 5 in a stationary 
manner. The adjustment of the disk 26 is effected by rotating the threaded 
spindle 27 at a handle 29. 
As a result of the invention, the distances between the grippers 3 and the 
gripper bases 10 can be adjusted centrally at the gripper stations 2 of a 
gripper cylinder in that the gripper bases 10 are adjusted in a radial 
direction via levers 15 to 18 and a disk 19, 26 arranged laterally to the 
cylinder and by means of the opposed helical toothed wheels 8. Otherwise, 
the grippers 3 are adjusted via an eccentric bearing 22, 23. 
The invention is not limited by the embodiments described above which are 
presented as examples only but can be modified in various ways within the 
scope of protection defined by the appended patent claims.