BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
FIG. 1 is a simplified 3D diagram of a glue applicator in the working position;
FIG. 2 is the glue applicator of FIG. 1 in the disconnected position;
FIGS. 3
a-3d are detailed views of a doctor blade drive at various angles of rotation;
FIGS. 4
a-4d are detailed views of a variant of a doctor blade drive at various angles of rotation; and
FIGS. 5
a-5d are detailed views of yet another variant of a doctor blade drive at various angles of rotation.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a glue applicator 1 of an adhesive binder for gluing the spines 20 of book blocks 21. For the sake of clarity, the book block 21 is transparent, and its edges are shown in dash-dot line. The glue applicator 1 consists essentially of a tank 3 containing the adhesive 8 and glue applicator rolls 6 rotatably supported in the tank, the rolls being immersed in the adhesive 8. The glue applicator rolls 6 are driven by a drive (not shown) and rotate in the same direction as the book block 21, which is being conducted past them in the transport direction 22. The adhesive 8 adhering to the surface of the glue applicator rolls 6 is formed into a homogeneous glue film by doctor blades 5 in correspondence with the distance “s” between the blades 5 and the glue applicator rolls 6, where the thickness of the glue film corresponds to the distance “s”. Areas at the beginning and end of the book block 21 should remain free of adhesive 8. This is achieved by moving the doctor blade 5 toward the glue applicator roll 6, as a result of which the distance “s” is reduced. In these areas, it is no longer possible for there to be any contact between the surface of the glue film and the book block spine 20, and the transfer of adhesive 8 to the book block spine 20 is avoided. After the glue has been applied, a roll 7, a so-called “spinner”, which is driven in the direction opposite the transport direction 22, smoothes out the glue film on the spine 20, carries away excess glue 8, and returns it to the tank 3. The doctor blades 5 are attached to shafts 4, which are supported pivotably in the bearings 9 in the tank 3. The doctor blades 5 are adjusted by actuating elements 10 mounted on the shafts 4. These actuating elements are driven positively by cam disk 14. The cam disks 14 are driven by motors 2 and are mounted permanently in the machine stand 15. It is advantageous for the actuating element 10 to have two rotatably supported guide rolls 11, 12, the first guide roll 11 resting on the radial 18, the second guide roll resting on the radial cam 19, which acts in a manner complementary to the radial cam 18. Depending on the variant of the cam disk 14, the actuating element 10 is designed with one or two levers 13. It can be advisable to use different glue applicators 1 to process different adhesives 8. The glue applicators 1 can be moved into and out of the machine as complete units in the direction of the axes of the glue applicator rolls 6. The doctor blade drives are disconnected preferably at the point where the guide rolls 11, 12 meet the radial cams 18, 19. For this purpose, the radial cams 18, 19 have feed sections 23, which, when the glue applicator 1 is moved into the machine, prevents contact between the guide rolls 11, 12 and the radial cams. The cam disk 14 must be at the appropriate angle during this operation, and the blades must be closed, i.e., the distance “s” is 0. This situation is illustrated in FIG. 3a, FIG. 4a, and FIG. 5a. Then the cam disks 14 are rotated—in the exemplary embodiment shown here, in the counterclockwise direction—in such a way that the beginnings of the working sections 24 are facing the guide rolls 11, 12. The guide rolls 11, 12 are thus now in contact with the radial cams 18, 19, and the distance “s” between the blades 5 and the glue applicator rolls 6 is still 0. This situation is shown in FIG. 3b, FIG. 4b, and FIG. 5b. This angular position of the cam disks 14 corresponds to the beginning of the working stroke. In FIG. 3d, FIG. 4d, and FIG. 5d, the cam disks 14 are shown in the end position, and the distance “s” has reached its maximum. By rotating the cam disks 14 within the working sections 24, it is therefore possible to adjust the distance “s”, where each angular position of the cam disks 14 corresponds to an associated distance “s” between the doctor blades and the glue applicator rolls. This situation is shown in FIG. 3c, FIG. 4c, and FIG. 5c. The cam disks 14 are driven by controlled motors 2. The angular positions and rpm's of the cam disks 14 to be achieved are calculated by a control device 17 connected to the motors 2, and the motors are controlled accordingly via the lines 16.
The design of the cam disk 14 with the essential features of the claims allows several variants.
The variant cam disk 14 in FIGS. 3a-3d has outside curves 25 for both the radial cam 18 and the complementary radial cam 19. Each of the variant cam disks 14 according to FIGS. 4a-4d and FIGS. 5a-5d has an outside curve 25 and an inside curve 26. Another variant cam disk 14 (not shown) has two inside curves 26. It is also conceivable that the radial cams 18, 19 could be located on a cam drum, the axes of the shafts 4 and of the cam drums being perpendicular to each other.
While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
Patent Application
20080003080
