Folding drum in a folding machine for a rotary press

Abstract: The known folding drum in a folding machine for a rotary press of the type that a web to be cut on the folding drum is guided and held by means of a plurality of bands aligned in the axial direction of the folding drum in parallel to one another as striding over a gap of the folding drum and tip end portions of a folding blade are projected to the outside of the folding drum through the gaps between the respective bands, is improved. The respective bands are divided into groups each consisting of at least two bands (27a,27b), band mount portions for each group are formed integrally, and the band mount portions are mounted to the folding drum via adjusting devices for the respective groups so that expansions in the circumferential direction of the bands can be adjusted. Preferably, the adjusting device is composed of an adjusting plate (40) engaged with an adjusting rack (26) to which the bands are mounted and an adjusting shaft (41), and the adjusting plate is mounted to the adjusting shaft at an eccentric position.

Description: BACKGROUND OF THE INVENTION: Field of the Invention: The present invention relates to a folding drum in a folding machine for a rotary press, and more particularly to improvements in a folding drum in a folding machine for a rotary press of the type that a web to be cut on the folding drum is guided and held by means of a plurality of bands aligned in the axial direction of the folding drum in parallel to one another as striding over a gap of the folding drum and tip end portions of a folding blade are projected to the outside of the folding drum through the gaps between the adjacent bands. Description of the Prior Art: One example of the folding drum in a folding machine for a rotary press of the above-mentioned type will be described with reference to Figs. 3 and 4. In these figures, reference numeral 1 designates a folding drum, numeral 2 designates a folding blade, numeral 3 designates a pair of folding rollers, numeral 4 designates a needle device, numerals 5 and 6 designate covers, numeral 7 designates a needle receiving rack made of rubber, numeral 8 designates a holder, numeral 9 designates bands, numeral 10 designates a fixed bracket, numeral 11 designates a slide bracket on the folding drum side which can be moved by means of a screw 13, numeral 12 designates a pin, numerals 14, 15, 16, 17, 18 and 19 designate bolts, and a cut web is folded up by means of a folding blade 2 of the folding drum 1 and a pair of folding rollers 3. Within the folding drum 1 is formed a vacancy 1c for supporting the folding blade 2 so as to be projectable to the outside of the folding drum 1, this vacancy 1c opens at the outer circumferential surface of the folding drum 1, and this opening portion of the vacancy 1c is called "folding drum gap 1b". At this folding drum gap 1b are disposed bands 9 as aligned at an appropriate interval in the axial direction of the folding drum 1 in four or five parallel raws, on end portions in the circumferential direction of the respective bands 9 are mounted to the folding drum 1 via a fixed bracket 10, and the other end portions in the circumferential direction of the respective bands are connected to a slide bracket 11 (a slide bracket that is movable by means of a screw 13) via pins 12. The tip end portions of the folding drum 2 project to the outside of the folding drum 1 through the intervals between these bands 9. DE-A-3 821 442 discloses a folding drum having bands and circumferential adjusting devices for the same. In the case of the folding drum in a folding machine for a rotary press in the prior art shown in Figs. 3 and 4 and described above, though a web to be cut on the folding drum 1 is guided and held by means of a plurality of bands 9 aligned in the axial direction of the folding drum 1 and disposed so as to stride over the folding drum gap 1b, a folded binder would flutter due to airflows in the folding drum gap 1b and in the gaps between the bands 9, hence faults such as end folding are liable to occur, and there was a problem that these faults resulted in unacceptable folded binders. SUMMARY OF THE INVENTION: It is therefore one object of the present invention to provide an improved folding drum in a folding machine for a rotary press which can produce folded binders of good quality, which can perform a high-speed printing operation, and which can shorten a printing time. According to one feature of the present invention, in a folding drum of a folding machine for a rotary press of the type that a web to be cut on the folding drum is guided and held by means of a plurality of bands aligned in the axial direction of the folding drum in parallel to one another as striding over a gap of the folding drum and tip end portions of a folding blade are projected to the outside of the folding drum through the gaps between the respective bands, the respective bands are divided into groups each consisting of at least two bands, band mount portions for each group are formed integrally, and the band mount portions are mounted to the folding drum via adjusting devices for the respective groups so that expansions in the circumferential direction of the bands can be adjusted. Preferably, the adjusting device consists of an adjusting plate engaged with an adjusting rack to which the bands are mounted and an adjusting shaft, and the adjusting plate is mounted to the adjusting shaft at an eccentric position. As featured above, in the folding drum of a folding machine for a rotary press according to the present invention, bands aligned in a plurality of rows are divided into groups each consisting of at least two bands, band mount portions for each group are formed integrally, the band mount portions are mounted to the folding drum via adjusting devices for the respective groups, and adjustment is effected by the respective adjusting devices in such manner that expansions in the circumferential direction of the respective bands may be equalized. Consequently, the gaps between the respective bands can be made narrow, hence upon folding a web, waving of the web at the folding drum gap is eliminated, it becomes possible to fold up smoothly, and folded binders of good quality can be produced. This operation is especially effective in the case where a rotational speed of a folding drum is high, thus a high-speed printing operation becomes possible, and a printing time can be shortened. The above-mentioned and other objects, features and advantages of the present invention will become more apparent by reference to the following description of one preferred embodiment of the invention taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS: In the accompanying drawings: Fig. 1 is a plan view showing one preferred embodiment of a folding drum in a folding machine for a rotary press according to the present invention; Fig. 2 is a vertical cross-section side view of the same taken along line II-II in Fig. 1 as viewed in the direction of arrows; Fig. 3 is a plan view showing one example of a folding drum in a folding machine for a rotary press in the prior art, taken along line III-III in Fig. 4 as viewed in the direction of arrows; and Fig. 4 is a vertical cross-section side view of the same. DESCRIPTION OF THE PREFERRED EMBODIMENT: Now the folding drum in a folding machine for a rotary press according to the present invention will be described in greater detail in connection to one preferred embodiment illustrated in Figs. 1 and 2. In these figures, reference numeral 1 designates a folding drum, numeral 2 designates a folding blade, numeral 7 designates a needle receiving rack made of rubber, numeral 21b designates a vacancy, numerals 22, 23 and 28 designate covers, numeral 24 designates a holder, numeral 25 designates a fixed bracket, numeral 26 designates an adjusting rack, numeral 27 designates a plurality of aligned bands mounted to the adjusting rack 26, numerals 30, 35 and 36 designate bolts, numeral 40 designates an adjusting plate disposed so as to engage with a circular hole in the adjusting rack 26, numeral 41 designates an adjusting shaft, and numeral 42 designates an adjusting device consisting of the adjusting plate 40 and the adjusting shaft 41. The above-mentioned plurality of (six in the illustrated embodiment) aligned bands 27 are divided into groups each consisting of at least two bands 27a and 27b, band mount portions for each group are formed integrally, said band mount portions are mounted to the folding drum 1 via adjusting devices 42 for the respective groups so as to be movable in the circumferential direction of the folding drum 1, and adjustment is effected by the respective adjusting devices 42 so that expansions in the circumferential direction of the respective bands 27 may be equalized. In more particular, the adjusting plate 40 is secured to the adjusting shaft 41 at its eccentric position deviated by a distance e from its center, said adjusting shaft 41 is mounted to the adjusting rack 26, and so, by rotating the adjusting plate 40 the adjusting rack 26 is moved and adjustment is effected in such manner that expansions of the respective bands 27 may be equalized. In the figures, reference numeral 28 designates covers for covering the respective adjusting devices 42. Next, description will be made in detail on the operation of the folding drum in a folding machine for a rotary press shown in Figs. 1 and 2. When a multi-layer cut web is folded up by projecting a folding blade 2 towards the web, a folded binder would flutter due to airflows in the folding drum gap 21b and in the gaps between the bands 27, hence faults such as end folding or the like are liable to occur, and these faults resulted in unacceptable folded binders. In addition, if the intervals between the tip end portions of the folding blade 2 projecting through the gaps between the bands 27 are too large, or a total width of the projecting portions of the folding blade 2 is narrow with respect to the width of the web, then poor folding such as scratches or no good folding lines would be generated. In the case where these problems are dealt with by narrowing the gaps between the bands 27, together with increase of the gaps between projections of the folding blade 2, the total width of the projections is decreased, and so, the problem relating to quality cannot be resolved. However, in the folding drum according to the present invention, a plurality of aligned bands 27 are divided into groups each consisting of at least two bands 27a and 27b, band mount portions for each group are formed integrally, said band mount portions are mounted to the folding drum 1 via adjusting devices 42 for the respective groups so as to be movable in the circumferential direction, and adjustment is effected by the respective adjusting devices 42 so that expansions in the circumferential direction of the respective bands 27 may be equalized. Consequently, the gaps between the respective bands 27 can be made narrow, hence upon folding up the web, waving of the web at the folding drum gap 21b is eliminated, it becomes possible to fold up smoothly, and folded binders of good quality can be produced. This operation is especially effective in the case where a rotational speed of a folding drum is high, hence a high-speed printing operation becomes possible, and a printing time can be shortened. As will be obvious from the detailed description of the preferred embodiment of the present invention above, according to the present invention, owing to the fact that in a folding drum of a folding machine for a rotary press, a plurality of aligned bands are divided into groups each consisting of at least two bands, band mount portions for each group are formed integrally, said band mount portions are mounted to the folding drum via adjusting devices for the respective groups so as to be movable in the circumferential direction, and adjustment is effected by the respective adjusting devices so that expansions in the circumferential direction of the respective bands may be equalized; the gaps between the respective bands can be made narrow, hence upon folding up the web, waving or fluttering of the web at the folding drum gap is eliminated, it becomes possible to fold up smoothly, and folded binders of good quality can be produced. This operation is especially effective in the case where a rotational speed of a folding drum is high, hence a high-speed printing operation becomes possible, and a printing time can be shortened. While a principle of the present invention has been described above in connection to one preferred embodiment of the invention, it is intended that all matter contained in the above description and illustrated in the accompanying drawings shall be interpreted to be illustrative and not as a limitation to the scope of the invention.

Claims: A folding drum in a folding machine for a rotary press, in which a web to be cut on the folding drum is guided and held by means of a plurality of bands aligned in the axial direction of the folding drum in parallel to one another as striding over a gap of the folding drum, and tip end portions of a folding blade are projected to the outside of the folding drum through the gaps between the respective bands; characterized in that said respective bands are divided into groups each consisting of at least two bands, band mount portions for each group are formed integrally, and said band mount portions are mounted to the folding drum via adjusting devices for the respective groups so that expansions in the circumferential direction of the bands can be adjusted. A folding drum in a folding machine for a rotary press as claimed in Claim 1, characterized in that said adjusting device consists of an adjusting plate engaged with an adjusting rack to which said bands are mounted and an adjusting shaft, and said adjusting plate is mounted to said adjusting shaft at an eccentric position.

Inventors: HIRAHARA HIDEFUMI C O MIHARA M, KUBOTA SATORU C O MIHARA MACHI, HIRAHARA, HIDEFUMI, C/O MIHARA MACHINERY WORKS OF, KUBOTA, SATORU, C/O MIHARA MACHINERY WORKS OF
Applicants: MITSUBISHI HEAVY IND LTD, MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1990
Main classification: B41F13
IPC codes: B41F13, B65H45