| 摘要 |
<p>The invention relates to an edge sensor for scanning the edge of a web of material, having a pivotable sensor arm which is connected to a switching device which can be actuated for the emission of at least one signal when the sensor arm is deflected. In known mechanical edge sensors, the sensor arm actuates electrical contacts or pilot valves through which signals are then generated. This is disadvantageous in that the sensor arm must exert a certain amount of force if the switching devices are to be actuated and in addition there is reduction or exaggeration of the stroke or force between the region in which the sensor arm rests against the edge and the region in which it actuates the switching device, unless the sensor arm is extended a very long way beyond its pivoting axis, which is also unfavourable. According to the invention, this is avoided by making the sensor arm support a metal element and giving the switching device an electrical proximity initiator which is arranged next to the path of motion of the element and works with the element in a contact-free manner.</p> |
