BRIEF DESCRIPTION OF THE DRAWING
The characteristics of preferred embodiments of the present invention are described in greater detail below with reference to the accompanying drawing in which:
FIG. 1 is a sectional representation of a first embodiment of an inventive roll bending device;
FIG. 1
a shows a detail of the roll bending processing zone in FIG. 1;
FIG. 2 is a sectional representation of a second embodiment of a roll bending device;
FIG. 2
a shows a detail of the roll bending processing zone in FIG. 2, and
FIG. 3 shows a roll bending device according to FIG. 1, in which the arrangement of the rotary tools is reversed.
DETAILED DESCRIPTION
FIG. 1 shows a roll bending device 6.1 for producing hinge-like bending lines 3a,b that border the spine region 2 in a cover sheet 1, for e.g., printed products such as books and brochures. The cover sheet 1 is respectively bent inward referred to its inner and its outer side 1a and 1b along bending lines 3a,b such that the spine region 2 is realized with a U-shaped cross section and the cover sheet 1 can be advantageously attached to a glued book block spine in a flawless fashion during the additional processing that is not illustrated in greater detail.
FIG. 2 shows an alternative roll bending device 6.2 that makes it possible to realize the cover sheet 1 with a box-shaped contour in the spine region 2, namely by bordering the spine region 2 with bending lines 4a,b that are respectively bent in a Z-shaped fashion. FIG. 3 shows a roll bending device 6.3 that is reversed in comparison with the variation shown in FIG. 1 and serves for realizing outwardly bent bending lines 5a,b that preferably form hinges of the front and the rear cover and are positioned at a defined distance from the spine region 2.
The disclosed roll bending devices 6.1 to 6.3 respectively consist of left and right pairs 7a,b of roll bending tools that are respectively realized and arranged in a mirror-inverted fashion, wherein these pairs of roll bending tools are spaced apart by the spine width B in the embodiments shown in FIGS. 1 and 2. Each pair 7a and b of roll bending tools features an upper tool 7.1 and a lower tool 7.2. The tools 7.1 and 7.2 are rotatively driven in opposite directions, wherein their rotational axes 10a and b are spaced apart from one another by an axial distance A.
In the roll bending device 6.1 according to FIG. 1, the upper tool 7.1 has a first rotary tool member 8.1 with a circumferentially projecting ring 12, the circumferential tool edge 12a of which is rounded with a defined radius 12b. The lower tool 7.2 has a second rotary tool member 9.1 with a conical outside surface 11a that is inclined toward the rotational axis 10b and features a projection 11a of triangular cross section.
The tool edge 12a of the first rotary tool member 8.1 cooperates with the inclined, conical outside forming surface 11a of the second rotary tool member 9.1, whereby the continuously transported cover sheet 1 lying therebetween is deformed in accordance with the roll bending principle. In this context, “conical” should be understood as exemplified by the inclined, substantially frustoconical surface 11a observable as, e.g., the left rotary tool 9.1 is viewed along the rotational axis 10b from the spine region 2.
In this embodiment, the inclination a of the outside forming surface 11a relative to the rotational axis 10b amounts to approximately 67.5°, but it should be noted in this context that the tools may be realized with any angle α between 30° and 90°.
The detail shown in FIG. 1a elucidates how the cover sheet 1 is compressed by the tool edge 12a in the bending line 3b cooperatively working against the confronting tool surface 11a, wherein a chamfer of sorts is produced in the cover sheet 1 due to the inclined outside forming surface 11a that acts as a counter bearing. The tool edge 12a projects substantially radially relative to axis 10a into confronting relationship with the inclined forming surface 11a either transversely (FIG. 1a) or substantially in parallel (FIG. 2a). These edges or inclined surfaces can have a curvature.
As mentioned above, FIG. 3 shows a roll bending device 6.3 that is reversed in comparison with the embodiment shown in FIG. 1. In this case, the rotary tool member 8.3 that serves as the upper tool 7.1 has the inclined outside forming surface 11a while the rotary tool member 9.3 used as the lower tool 7.2 features the tool edge 12a.
In the second embodiment of the roll bending device 6.2 shown in FIG. 2, rotary tool members 8.2 and 9.2 that are essentially realized identically are used as upper and lower tools 7.1 and 7.2. The rotary tool members 8.2 and 9.2 respectively feature a projection 11 of triangular cross section analogous to that described above with reference to the rotary tool members 9.1 and 8.3. The two outside forming surfaces 11a are inclined in a complementary fashion such that the rotary tool members 8.2 and 9.2 with their outside surfaces 11a can be adjusted relative to one another. In this context, see the detail illustrated in FIG. 2a.
The revolving projecting edge of one rotary tool member 8.2 or 9.2 respectively cooperates with the outside forming surface 11a of the other rotary tool member 9.2 or 8.2 in the form of a radiused tool edge 11b in this case. The cover sheet 2 is bent inward once along the bending line 4a or 4b and bent outward again once directly adjacent thereto such that a bending point of essentially Z-shaped cross section is produced.
In the embodiment shown in FIG. 2, the right pair 7b of roll bending tools is arranged stationarily while the left pair 7a of roll bending tools can be adjusted with respect to the spine width B as symbolically indicated with the reference symbol VB.
Another adjustment VA can be realized by varying the axial distance A between the two tools 7.1 and 7.2. This adjustment makes it possible to vary the working position of the tool edge 12a on the outside forming surface 11a. In the second embodiment of the roll bending device 6.2 shown in FIG. 2, this makes it possible to vary the distance between the two oppositely directed chamfers in the bending line 4a,b or its compressed surface in the cover sheet, respectively. In this context, see FIG. 2a.
In addition, it is possible to realize an adjustment VD of each pair 7a and b of roll bending tools in order to adjust the processing distance of the tool edge 12a (or 11b) relative to the corresponding outside forming surface 11a in the sense of a basic setting. This also makes it possible, in principle, to realize a defined adjustment of the cover sheet thickness.
However, an adjustment VD of the processing distance as well as an adjustment VA of the axial distance A is not required during the normal operation of an inventive roll bending device 6.1 to 6.3 of this type. Various cover sheet materials and thicknesses can be processed with one and the same adjustment of the pairs 7a and b of roll bending tools. Bending lines 3a,b, 4a,b or 5a,b of adequate quality are produced in all instances, wherein these bending lines are characterized in that they bend easily and feature no torn surfaces.
In order to carefully process the cover sheet 1, the ring 12 and therefore the tool edge 12a may consist of an elastic material. However, it was determined that hard tool edges 12a and outside surfaces 11 are advantageous with respect to producing high-quality bending lines 3a,b, 4a,b or 5a,b in a multitude of different sheet materials.
Patent Application
20080020917
