Patent Application
20060181011
Field of the Invention
The invention pertains to a transport belt, in particular a suction belt, for conveying sheets. The transport belt can be driven, deflected over at least two rollers, and guided over a conveyor table.
A transport belt of that type is described, for example, in German published patent application DE 44 13 286 A1. There, a deflection roller is arranged in the overlap region of the sheet to be aligned on front lays. The transport belt, when deflected, tends to turn up slightly at its margins or edges which are fabricated within exact tolerance limits. As a result, markings are left behind on the undersides of the sheets. In particular in the case of sheets which are coated or already printed on the underside, these markings from the transport belt have a negative impact in terms of quality, and in the worst case they result in rejects.
It is accordingly an object of the invention to provide a transport belt with a structure that overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which provides for a transport belt wherein the tendency to cause markings on the sheet is avoided, or at least reduced.
With the foregoing and other objects in view there is provided, in accordance with the invention, an improved transport belt for conveying sheets, such as an endless suction belt, configured to be driven, deflected over at least two rollers, and guided over a conveyor table. The improvement is found in the fact that the transport belt has lateral edges, or margins, formed with an edge structure.
In accordance with an added feature of the invention, the edge structure is a roughness with a laterally extending amplitude of RZ>1 millimeter.
The edge structure may have a shape described as zigzag, sinusoidal, square wave, sawtooth, and/or meandering.
With the above and other objects in view there is also provided, in accordance with the invention, a conveying table for conveying sheets to a sheet-processing machine, comprising:
a suction box;
at least two deflection rollers; and
an endless transport belt guided over said suction box and deflected about said deflection rollers, said transport belt being a suction belt with lateral edges formed with an edge structure.
It is a particular advantage of the invention that the edges of the transport belts have a high roughness or substantially a defined edge structure in a region facing the belt. As a result of this measure, marking of the transport belts on the underside of the sheets is avoided. In particular, the edges of the transport belts can be formed in the shape of a zigzag, sinusoidally, irregularly, in the shape of prongs, in the shape of sawteeth or in the shape of a meander. Alternatively, it is proposed to render the edges safe by means of a chamfer or rounding.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a Transport Belt Forms, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
Referring now to the figures of the drawing in detail and first, particularly, to
The sheet stack 8 rests on a pile board or stack board 10 which can be raised under control. The removal of the sheets 7 is carried out from the top side of the sheet stack 8 by means of a so-called suction head 18 which, inter alia, has a number of lifting and dragging suckers 19, 21 for separating the sheets 7. Furthermore, blowing devices 22 for loosening the upper layers of sheets and sensors 23 for tracking the stack are provided. In order to align the sheet stack 8, in particular the upper sheets 7 on the sheet stack 8, a number of lateral and rear stops 24 is provided.
The sheets 7 arriving in the front region, facing the press, are aligned in the transport direction by means of front lays 26 and transversely with respect to the sheet transport direction by way of side lays, i.e., lateral aligning means 27. In this case, a relative movement between sheet and transport belts 29 arises, which can lead to the above-mentioned, undesirable markings. Such relative movements can also arise, for example, if the sheets are moved more quickly by another transport apparatus that is provided than by the transport belt 29.
The feed table 9 in the exemplary embodiment according to
In a further alternative embodiment, the edges 34, 36 of the transport belt 29 may be provided with a chamfer 37, as illustrated in
This application claims the priority, under 35 U.S.C. § 119, of German patent application No. 10 2004 046 293.3, filed Sep. 24, 2004; the entire disclosure of the prior application is herewith incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2004 046 293.3 | Sep 2004 | DE | national |
