Printing – Rolling contact machines – Rotary
Reexamination Certificate
2003-06-06
2004-05-18
Hirshfeld, Andrew H. (Department: 2854)
Printing
Rolling contact machines
Rotary
C101S248000, C101S483000, C101S228000, C101S183000, C101S479000, C399S016000
Reexamination Certificate
active
06736062
ABSTRACT:
BACKGROUND INFORMATION
The present invention relates to a conveyor system for a sheet of printing material in a printing material processing machine, including a running member which can be moved through the machine along a transport path using a drive, and further including a number of encoders which are arranged along the transport path and used to sense the position of the running member. Moreover, the present invention relates to a method for generating a drive signal of a conveyor system, including a running member, for a sheet of printing material in a printing material processing machine, by evaluating signals of a number of encoders which are distributed along a transport path of the running member.
In printing material processing machines, such as printing units, printing presses, print finishing machines (folding apparatuses, gatherer-stitchers, adhesive binders, or similar), or the like, the movement of a sheet of printing material, typically on a section of a transport path of conveying elements, can be accomplished using a conveyor system controlled in open or closed loop. The conveying elements include holding means or fixing means for holding a sheet of printing material at least during an interval of time. When moving elements, so-called “running members” on a long, in particular, closed transport path in a circuit, it is first of all required to use a suitable drive, such as a flexible drive, a rack-and-pinion drive, a linear motor, or the like; secondly, it is required to feed back the positional information to the controller for closed-loop operation.
In the case that a linear motor is used, energy supply to the conveyor system is typically provided by synchronous motors of which the secondary member is moved, that is, forms the running member. It is also possible to use a plurality of secondary members or running members. The static member includes the primary member, which is suitably segmented to be able to drive a plurality of running members on one path. In order to sense the position of the running member, that is, for signal acquisition purposes, diverse configurations of suitable encoder arrangements for generating a signal by detection and suitable detection objects have already been proposed.
To acquire the positional information of the conveyor system, different principles are available whose scale members and encoders (i.e., also sensors) can be designed and arranged differently. In the prior art, there are length measuring systems which are based on optical, magnetostrictive, electrostatic, or inductive and/or resistance principles. In principle, the measuring systems differ from each other in their measurement method, which can either be an implicitly absolute or an incremental one. A common shortcoming of known measuring systems is the limited length of their measuring path for high-accuracy position sensing at high speed. In other words, it turns out to be very difficult to achieve high position resolution at high speeds over a long section of the transport path for a running member in a transport system.
A conveyor system for conveying material in sheet form or sheets of printing material in a rotary printing press is disclosed, for example, in German Patent Application No. 197 22 376 A1. This conveyor system includes two guide rails running parallel to each other, in each of which one associated propulsion element is guided in a play-free manner, the propulsion element forming the running member of an electric linear drive. For example, according to German Patent Application No. 197 22 376 A1, the two propulsion elements are designed as link chains having at least two individual links of magnetizable material and connected by a cross-member to which are mounted grippers for holding the sheet. The propulsion elements are driven by drive stations that are located outside the guide rails and have coils which form the stator of the linear drive and which are spaced apart at distances substantially smaller than or equal to the length of the propulsion devices.
SUMMARY OF THE INVENTION
German Patent Application No. DE 101 62 448 A1 describes a device for sensing the position of a running member in a conveyor system of a printing material processing machine. A number of encoders which, in particular, can be evenly spaced apart from each other, are arranged along a position coordinate line of a (preferably closed) transport path. The conveyor system drive is preferably a linear motor; the running member has a scale member or a position mark. The scale member or the position mark can be linear in shape or punctiform. Preferred embodiments of the measuring system are optical encoders or magnetic field detectors. The encoders are arranged such that at certain positions of the running member, at least two neighboring encoders deliver non-vanishing signals. This arrangement can also be referred to as overlapping arrangement.
An object of the present invention is to provide a conveyor system for a sheet of printing material in a printing material processing machine such that the driving of the conveyor system is guaranteed with high quality.
According to the present invention, a conveyor system for a sheet of printing material in a printing material processing machine includes a running member which can be moved through the printing material processing machine along a transport path using a drive (drive control and driving element), as well as a number of encoders which are arranged along the transport path, preferably in an overlapping arrangement, and used to sense the position of the running member. The printing material is capable of being held on the running member at least along a section of the transport path or path of the running member. The encoders are connected to an evaluation unit for progressive sampling of the encoder signals. In the evaluation unit, an active encoder and a passive encoder can be specified at least for an interval of time so that in a signal processor unit of the evaluation unit a drive signal, in particular, an incremental signal, can be or is generated on the basis of a change in amplitude of the signal of the active encoder and a change in amplitude of the signal of the passive encoder. For different time intervals, the active and passive encoders can be different. The transport path of the running member is preferably closed. In said time interval, the change in amplitude of the active encoder can be used during a first period of time and the change in amplitude of the passive encoder can be used during a second period of time for generating the drive signal. Preferred encoders are so-called “sine/cosine encoders”, that is, encoders having two encoders signals which are shifted in phase relative to each other.
According to the present invention, a method for generating a drive signal of a conveyor system, including a running member, for a sheet of printing material in a printing material processing machine is based on the evaluation of signals of a number of encoders which are distributed along a transport path the running member and which, in particular, can be evenly spaced apart from each other: The encoders are sampled progressively. Out of the number of encoders, an active encoder and a passive encoder are specified at least for an interval of time. A drive signal is generated on the basis of a change in amplitude of the signal of the active encoder and a change in amplitude of the signal of the passive encoder.
In different time intervals, it is possible to specify different active and passive encoders of the number of encoders. In particular, a so-called “handover” from a first active and a first passive encoder in a first time interval to a second active and a second passive encoder in a second time interval can take place. These handovers can be continued between further time intervals in a corresponding manner for further encoders. The generation of a drive signal is based on the change in amplitude of a signal of one of the number of encoders that has been determined to be the active encoder for a time int
Frank Hendrik
Maier Stefan
Raquet Daniel
Davidson Davidson & Kappel LLC
Hamdan Wasseem H.
Heidelberger Druckmaschinen AG
Hirshfeld Andrew H.
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