Advancing material of indeterminate length – With material-responsive control means – To position material laterally
Patent
1989-06-16
1994-07-12
Stodola, Daniel P.
Advancing material of indeterminate length
With material-responsive control means
To position material laterally
25022726, 25022724, 250548, 226 20, 226 45, B65H 2302, G02B 514
Patent
active
053280725
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a process for locating the edges of moving webs, such as paper webs, dryer felts, wire screens, textiles, foils and similar, where a light signal of a photoelectric relay is emitted from a signal output arranged in the area of the web edge, toward the web edge, and the reflected or unreflected light signal is received by a signal input and converted by the photoelectric relay to an on/off signal which is used for display and as a control variable for the position of the web edge.
In the control of revolving machines of any kind where web type materials are being moved, monitoring the web edges with regard to tracking is indispensable in order to avoid damage to either the machine or to the web itself. Examples are paper webs, dryer felts in paper machines, wire screens, textiles, foils and similar. Basically the same applies to the measurement of coil diameters on winders, unwinders and coilers, where all of the measures required for actual value acquisition in all areas of this type need to take place without contact, since even the slightest contact forces are harmful to the measuring object.
In many cases, however, for instance on the wires and dryer felts of paper machines, mechanical scanners are used in practice which upon contact with the web edge effect an electronic or pneumatic control. Very popular, this procedure may easily cause damage to the measured material through friction on the web edges, especially in the case of high-speed machines.
In a prior process of the initially cited type, though, the actual value is captured optically and without contacting the measured material, but there are two photoelectric relays used here which through pistons control a guidance device. The disadvantage of this prior procedure is that locating a web edge requires already two photoelectric relays between which the actual value for the web edge position is located. Consequently, also the locating of the web edge is comparatively inaccurate. Additionally, this type of actual value acquisition for the web edge requires a guidance system that is pulsed through magnetic valves and has a comparatively complex structure. In this prior process, the actual value is determined by meeting the condition that one photoelectric relay is covered whereas the other is exposed. Naturally, this condition entails also startup problems, since this condition is met also when the web edge is being approached from outside.
Based on this prior art, the problem underlying the invention is to propose a process of the initially mentioned type and a device for the application of the process where an actual value acquisition is possible that works continuously without contact and optically.
This problem is inventionally solved essentially in that the locating of the web edge is performed continuously in that the signal output and the signal input orbit jointly and constantly on a path which intersects the web edge twice, and in that from the input/output signals obtained in each revolution the respective position of the web edge is determined.
It is obvious that this procedure enables a continuous monitoring of the web edge position which involves no contact whatsoever. To be understood as an orbital trajectory is one--irrespective of whether it is rectilinear or curving--which is self-contained. This continuous actual value acquisition of the web edge makes it possible to design the control section with conventional rules. At the same time it is also possible, e.g., to perform a noncontact measurement of coil diameters on winders and unwinders, so that a travel control for the edge sensor is achievable in a simple manner.
Another advantage is that the process can be performed with a single photoelectric relay and, as will yet be explained in detail farther down in conjunction with the inventional device, enables a distinctly rugged design.
In a preferred embodiment of the invention, the signal output and signal input are being moved along a circular path which intersects the web edge.
In modified embodiments, in
REFERENCES:
patent: 3501642 (1970-03-01), Wastesson
patent: 3606119 (1971-09-01), Callan
patent: 4021031 (1977-05-01), Meihofer et al.
patent: 4384686 (1983-05-01), Wiley et al.
patent: 4409477 (1983-10-01), Carl
patent: 4469941 (1984-09-01), Palmer
patent: 4472052 (1984-09-01), Lofgren
patent: 4720629 (1988-01-01), Parker
patent: 4848632 (1989-07-01), Mack et al.
Lieberg Helmut
Ruessmann Gerd
Bowen Paul
J.M. Voith & GmbH
Stodola Daniel P.
LandOfFree
Device for locating the edges of moving webs does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for locating the edges of moving webs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for locating the edges of moving webs will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-390909