DE3336726A1 - Edge sensing apparatus - Google Patents

Abstract

The invention relates to an edge sensing apparatus for a running web of material with a support on which at least one sensing element is arranged. Known apparatuses of this type have either a mechanical sensor arm which actuates electrical contacts when there is a deviation or an opto-electronic sensing element which scans the edge of the web of material without contact. When the mechanical sensor arm is used, it is difficult to derive exact signals which indicate the movement of the edge in a very small space without convergence. Opto-electronic sensing elements, on the other hand, cannot be used with certain web materials or web edges. According to the invention, this is avoided by providing a digital sensing element and a mechanical sensing element, the digital sensing element plotting the edge indirectly via the mechanical sensing element when the latter is in an operating position and plotting the edge of the web of material directly when the mechanical sensing element is moved from the operating position into a passive position.

Description

The invention relates to an edge sensing device in the preamble

of claim 1 specified type.

Such edge sensing devices have with moving webs indicate whether, how far and in which direction a web edge runs, with it Corrective movements for the material line can be controlled with signals derived therefrom are to lead them in a desired solo career. Well-known edge feeler device actuate functions with mechanical feeler arms with an extension of the feeler arm in addition to its pivot bearing, electrical switching devices or position sensors, to get the signals you want. To gear reduction between the actual To avoid the edge and the movements transmitted to the switching devices, a great structural effort would have to be made, given the limited space in addition to the web is unfavorable. Furthermore, the feeler arm must always have an increased actuation force apply or he then has such a large amount of water that he may have sensitive Web material damaged or not sensitive due to excessive contact pressure works enough. Well-known non-contact sensing elements, e.g. after the opto-electronic In principle, these disadvantages do not have these disadvantages, but they cannot be used for different ones Use materials and web edge configurations, and then not, if no light is reflected, or if too much light passes through, or if the Edge is so discontinuous or thinly frayed that it cannot be optically scanned.

The invention is based on the object of an edge sensing device to create the type mentioned, which is characterized by an extremely compact Construction excels and which is also able to handle the edges of all in practice occurring web materials and also edge courses that were previously difficult to scan to be recorded precisely and sensitively.

The task is he according to the invention by the in the characterizing Part of claim I specified features solved.

With this design of the edge sensing device can all be in Scan web materials occurring in practice. Also so far on opto-electronic Edge configurations that can hardly be scanned can be scanned perfectly. This is achieved in that the mechanical sensing element is not directly the Switching devices or position transducers actively operated, but from the contactless working sensing element is scanned, which is not necessarily in this mode of operation needs to adjust to the material of the web or the shape of the edge, but only on the mechanical feeler. In the case of materials or fabric edges, which anyway perfectly scanned by the non-contact sensing element the mechanical sensing element remains in its passive position. It kicks thus in practice there is no longer a case where this edge sensing device is material-related or for reasons related to the shape of the edges. Because the mechanical antennae no direct actuation of switching devices or position sensors to be carried out but is scanned without contact, it can be built gracefully and small and train very swiveling. The contactless feeler member leaves also train very small, so that overall the edge sensing device a very compact structure is obtained, which is extremely important. the The scanning accuracy and the response behavior are particularly precise and sensitive. The universal usability of this edge sensing device results from the three different modes of operation, which consist in that otherwise optoelectronic edges that cannot be scanned, the mechanical sensing element to the non-contacting one Feeler element replaces the edge to be scanned that can be scanned without contact the material web materials the mechanical sensing element remains in a passive position and the contactless, i.e. opto-electronically working sensing element alone directly the web and web edge scans and that with a clean edge course having, contactlessly difficult to scan material web materials the optical or only electronic guide link not the material web, but only the edge in relation to scans on a reference surface.

A particularly favorable operation of the device is achieved with the features of claim 2 achieved. Have these two alternatives respectively advantages for themselves. In the case of the analog way of working, they are very simple and inexpensive Wise width areas recorded at the web edge. The second alternative, the In practice, digital feeler will often be given priority because it is not susceptible Works flawlessly against dust and dirt and commands very sharp edges granted.

An expedient embodiment of the invention is based on claim 3 emerged. With the ribbon-shaped light source, which comes from a light stick or just a few elongated light emitters is formed, and the band-shaped a.sordinate receivers the result is a broad scanning range, either the location of the mechanical Feeler link or the position of the edge can be determined directly. As the recipient can be activated individually, different, discrete signals can be generated generate, e.g. digitally, with which the control of the web run very much can be carried out precisely and quickly. This also makes the scanning range extreme lay out big.

The feature of claim 4 is particularly useful because infrared transmitting diodes work parailel and have a very high light emission, which leads to a very help precise and sharp-edged delimitation.

For structural reasons, an embodiment is also expedient, as it emerges from claim 5. Several infrared transmitter diodes in this arrangement take up very little space in the web direction. The same applies the recipients, despite this narrow width in the direction of web travel, a large one Can cover the work area. For this reason, for example, the digital one is building Feeler element extremely small in the direction of travel of the web and also needs to be transverse There is only as much space for the material web running direction as there is the width of the work area is equivalent to. An infrared temperature sensitive is preferably used as the receiving element Photo transistor is used, which has a very narrow sensitivity level, in order to exclude stray light as much as possible.

The compact design is also made possible by the features of claim 6 favored, since the light source and the receiver are on the same side of the web and are relatively close together. The acute angle of reflection has made for the small structural unit and in avoiding secondary light and finally for one precise reflection shown at its best.

A long and reliable function of the invention comes from the feature Benefit from claim 7, since the inevitable contamination when scanning webs of material not directly to the light source or the receiver: can. In addition, lets by an appropriate selection of the disc any influence of extraneous light switch off beforehand.

The feature of claim 8 also contributes to this positive effect at, as light reflected from unevenness in the material web or from the environment does not hit the receiver, but is absorbed in the tunnel-shaped tubes.

From a structural and assembly point of view, the feature is also of claim 9 important. This gives the digital sensing element a very compact design shape and can be easily prefabricated as a complete assembly unit and, if necessary, also quickly replace.

For maintenance and repair reasons is also the feature of claim 10 is important because in the event of a defect in the optoelectronic Feeler element whose working components are practically exchanged with one hand movement can be.

Another useful feature emerges from claim 11.

With this surface, the work of the opto-electronic way functioning sensory link can be improved. A reflection surface is used for be provided in the event that the web is not able to the light reflect, e.g. because they are darkly colored or have a restless surface structure Has. In this Fall is what is reflected from the reflection surface Light used to scan the edge of the web. If, on the other hand, the material If the web is able to reflect the light well, the absorption surface helps determine the respective position of the web edge in relation to the recipient.

Another important idea is contained in claim 12. A such one-armed lever requires relatively little space to accommodate it and can be trained so gracefully that it performs a very smooth work cycle.

The feature of claim 13 is also expedient. The scanning flag is located in each case on the edge of the material web, while the cover flap corresponds to the optoelectronic Filing element shows the exact position of the web edge. It is special Advantage that between the movements of the web edge and the movements of the cover flap practically no motion reduction takes place, so that the movements of the web edge can be tapped unaltered by the optoelectronic footer. This will be done before especially when the features of claim 14 are used. As well as both the design and the attachment are simpler in the case of a one-piece part.

The feature of claim 15 is particularly useful because the The reference edge is then the fictitious web edge for the digital sensing element, for example represents that can be scanned cleanly. Especially with frayed edges this reference edge is used to determine the true fixed edge, for example be of great advantage for the subsequent linking of the web.

So that the part of the mechanical sensing element lying on the edge Moving practically parallel to the web of goods is also a feature of the claim 16 important.

Another useful feature is contained in claim 17.

This support bracket becomes the material web under normal working conditions do not touch. Only if the vibrations are too strong or if the material web sags, If, for example, the run of the web is stopped, the bracket supports the web against sagging from, whereby there is also the advantage that the edge sensing device then also determine the exact position of the web edge can, as the material web edge both in the contact area of the mechanical sensing element and must remain in the working area of the optical sensing element.

Another useful feature is contained in claim 18.

Limiting the swivel range of the sensor arm prevents that the feeler arm moves out of the working area of the optical feeler element, whereby these are overloaded with information to be processed separately could.

Structurally, the aforementioned requirement can be particularly simple Realize claim 19.

Another useful embodiment is based on claim 20 emerged. With this design, the pivoting range of the sensor arm is limited in the work area structurally connected to the swivel bearing for the sensor arm, that this can then be pivoted into the passive position and held in this becomes when the optical sensing element works alone. The latching has the advantage that only by the movement of the feeler arm this in the respective positions remains without working with a tool. In the passive position the sensor with the scanning lug and the cover lug are located above the support body the device where it is protected and does not interfere with work and also cannot fall down onto the web by itself.

Structurally, this requirement can be particularly simple according to the claim 21 realize. Such Kugelverrastungen are simple and very effective and leave easily adjust their locking strength.

Another important aspect is contained in claim 22.

This waiting position is intended for those cases in which the web is adjusted or where the cover plate of the optical sensing element is cleaned. The feeler arm remains in the Waiting until he is from Hand swiveled back into its working position or even transferred to the passive position will.

Another, expedient embodiment of the invention is based on the claim 23 emerges. In this case, the sensor arm can be pivoted around another pivot axis, when it is brought into the passive position and locked there than with his Swivel movement in the working position. The pivot bearing for the passive division leaves very easy to train, while the swivel mounting for the working of the sensor is easy and stable to train.

Another, expedient embodiment of the invention is based on the claim 24 emerges. The support bracket used for security is here simultaneously with a entrusted the second function by taking up the plate, which is used in certain web materials or pand courses are only brought. It is particularly advantageous to use the sliding Plate with both a reflective and an absorbing reference surface to prove.

This plate can then be moved particularly easily when the Features of claim 25 are given.

Finally, an important aspect is also contained in claim 26. Thanks to the compact design of the device, which results from the small mechanical There is a sensing element and the optical sensing element, which is also small, can be integrate the device with practically no effort in control devices for the web run, so that the edge is tapped wherever to correct on the Material web is acted upon.

Embodiments of the invention are explained with the aid of the drawings.

Show it Fig. 1 is seen in the direction of web travel first embodiment of an edge sensing device, partially in section; Fig. 2 the edge sensing device of Fig. 1 rotated by 900 and that in the direction of view from the middle of the web to the edge, partly in section; 3 shows a further embodiment an edge sensing device viewed in the direction of travel of the web; Fig. 4 is a plan view to the embodiment of FIG. 3; Fig. 5 shows an enlarged detail of the Sensing device; Fig. 6 shows a horizontal section through the detail of Fig. 5 and Fig. 7 and 8 are schematic representations of two different working principles of the digital feeler.

An edge sensing device 1 according to FIGS. 1 and 2 has an as Housing formed support body 2, on which with a flange 3 an L-shaped curved support bracket 4 is attached. A pivot bearing is located on the support body 2 5. In the support body 2, a space 6 for a digital sensing element 7 is formed covered downward in the direction of the support bracket 4 by a translucent pane 8 is. In the pivot bearing 5, a mechanical sensing element 9 is arranged, which as a one-armed pivotable sensor arm 9a is formed, which is a depending on the lower end Carrying scanning lug 1Q, which is integral with an approximately horizontally extending cover lug 11 is connected. The scanning lug 10 with the covering lug 11 is located in the 1 and 2 shown working position of the mechanical sensing element 9 between the support body 2 and the support bracket 4.

With the edge sensing device 1, the run of an edge 13 becomes a Web 12 scanned, with a view to their lateral movements transversely to the direction of web travel. Signals are derived from these movements can be used to control web guiding devices.

The feeler arm 9a of the mechanical feeler member 9 is in its working position between two positions A-B, indicated by dashed lines, which are the limits of his Indicate work area. Furthermore, the feeler arm 9a of the mechanical feeler member 9 pivot into a waiting position W (indicated by a full circle with a cross), in which it is adjacent to the underside of the support body 2. This waiting position W is used to carry out adjustment work for the web 12 or similar work, in which the edge sensing device 1 does not need to work.

In Fig. 1, the web 12 is shown resting on the support bracket 4. During normal operation, however, the web 12 is at a distance above the support bracket 4 run. The scanning flag 10 then rests on the edge 13 of the web 12 and pivots the feeler arm 9a of the mechanical feeler member 9 as a function of the sideways movements of the edge 13. In the support bracket 9 is also a sliding guide 14 designed for a plate 29, the purpose of which will be explained later. In the swivel bearing 5 and also on the support body 2 is the pivot axis of the feeler arm, indicated by 28 9a of the mechanical sensing element 9 is stored. On the pivot axis 28 is a disk-shaped Element 15 is arranged, which can be rotated relative to the pivot bearing 5. In the element 15, two balls 16, 16a are axially displaceably guided, those on the free face side of the pivot bearing 5 locking pans 17 are assigned such that the balls 16 can engage in different pivot bearings of the element 15 and the element 15 then set in the predetermined rotational positions.

In the pivot axis 28 there is also an extension 18 in the form of a transverse pin arranged, which cooperates with stops 19 in a recess 19a in element 15 in such a way that that he has the two end positions in positions A-B (indicated by dashed lines in Fig. 1) of the feeler arm 9a of the mechanical feeler member 9 is limited.

A nut 20 is screwed into the other end of the pivot bearing 5, which is penetrated by the pivot axis 28 and a pin 21 wearing, at which one end of a torsion spring 22 is anchored, which is at its other end supported on a further transverse pin 23 in the pivot axis 28 and the feeler arm 9a of the mechanical sensing element 9, a force directed clockwise in FIG. 1 which holds it with the scanning flag 10 on the edge 13.

The balls 16, 16a are loaded by springs 24, their bias can be changed by adjusting screws 25.

In the working position of the feeler arm 9a shown in FIGS. 1 and 2 of the mechanical sensing element 9, the balls 16 are in the vertically aligned and diametrically opposite Ra stpfannen 17 in the pivot bearing 5 engaged. The rotational position of the element 15 is thus determined. The feeler arm 9a can pivot only in one area that is formed by the recess 19a Stops 19 for the transverse pin 18 is limited. If, however, the feeler arm 9a (in Fig. 1) is pivoted counterclockwise into the waiting position W, takes the cross pin 18 through the recess 19, the element 15 until the balls snap into the further locking pans 17 offset in the radian measure and the element 15 then set in this position. If, however, the feeler arm 9a (in Fig. 1) clockwise by 180C into a so-called

Is pivoted passive position, the element 15 rotates with until the balls 16, 16a swap their locking pans 17, snap in again and thus the Feeler arm 9a in the passive position pivoted upward over support body 2 determine.

Referring to Figures 3 and 4, there is another embodiment of an edge sensing device 1 'recognizable, which differs from the embodiment described above in that that the feeler arm 9a of the memechanical feeler member 9 with its pivot bearing 27 pivotable about a pivot axis 26 lying vertical to the web plane on the support body 2 is. As a result, the scanning flag 10 moves when the edge moves sideways 13 of the web 12 parallel to the plane of the web. The feeler arm 9a of the mechanical Antennae 9 is, however, a further one, parallel to the direction of travel of the web lying pivot axis 28 mounted in the pivot bearing 27, around which it is approximately 1800 can be swiveled up into the passive position.

In Fig. 4, the digital sensing element 7 is indicated, which is in the support body 2 is located and in a manner explained later by the cover plate 8 either with the mechanical sensing element 9 cooperates indirectly around the edge 3 of the web 12 to be scanned, or when the feeler arm 9a of the mechanical one is in the passive position Sensing member 9 scans the edge 13 directly.

In the support bracket 4, the plate 29 is displaceable in the sliding guide 14 guided, which carries either a reflection surface or an absorption surface 30, the purpose of which will be explained later. The plate 29 can be opened by means of a handle opening 31 from the position shown in FIG. 4 into the working area below the digital Move the feeler element 7 if the feeler arm 9a of the mechanical feeler element 9 has been swiveled up into the passive position. The mobility of the plate 29 is indicated by a double arrow 32.

The structure of the digital sensing element can be seen in detail from FIGS. 5 and 6 7 shows that in the embodiments of the web sensing device 1, 1 'for cooperation with qen mechanical sensing element 9 or for independent work. That digital sensing element 7 works opto-electronically, preferably with infrared light, which consists of one of several infrared lamps 33, which can be diodes Light source is emitted. The infrared lamps 33 are in a housing 38 held in a version 43 ..

You are on connecting lines 34 with a circuit board 35 in Connection which is easily detachably attached in the housing 38 by means of a screw. In the circuit board 35 receivers 36 are also embedded, which are not shown Way to output signals to further lines are connected. In the case 38 tunnel-shaped tubes 39, 40 are provided in which both the lamps 33 and especially the receiver 36 at a significant distance behind the translucent Disc 8 are arranged. These tunnel-shaped tubes 39, 40 have the task of the influence of extraneous light or unevenness in the web at different angles to prevent reflected light from impinging on the receivers 36.

As shown in particular in FIG. 6, the infrared lamps 33 are in one Arranged row, as well as the receivers 36, which in a considerable number may exist. The longitudinal direction of the row is transverse to the direction of travel of the web, see above that there is a wide scanning range. The receivers 36 are either close together close together or are even offset in a zigzag shape from one another, so that they are overlap. Each receiver 36 is able to use a received infrared light beam to emit a signal so that the position of the web or the web edge 13 is as accurate as possible is scanned.

The infrared lamps 33 emit infrared light 41, part of which is reflected and hits the receiver 36 as reflection light 42.

In the housing 38, a trough 44 is also formed, which is adjacent to the fastening part of the support body 2 is located. In the support body 2 are in this embodiment for easy fixing of the edge sensing device 1 bores 45 provided, in the balls 46 loaded by springs 47 protrude. With the holes 45 can Slide the support body onto two mandrels and lock it into place with the balls 46. For maintenance or repair work, the support body can be pulled off again very easily.

With reference to FIGS. 1 to 4, FIG. 5 and those explained below 7 and 8, the operation of the edge sensing device is to be explained: At Presence of a web 12 of a reflective material with a clean, optically perfectly scannable edge 13, the feeler arm 9a of the mechanical feeler member 9 in the passive position panned. The digital feeler feels the edge 13 directly by using the infrared lamps used as infrared transmitting diodes 33 emit parallel light beams 41 and are controlled in such a way that the light beams 41 pulsating in the direction indicated by an arrow R in FIG generated from right to left over the work area (scanning). By doing Part of the work area that is not covered by the web 12 is the emitted Infrared light 41 lost. On the other hand, it is the one who intervenes in the work area Part of the web 12 thrown back as reflection light 42 and from the recipients 36 intercepted, which generate corresponding signals that the exact position of the edge 13 show. The movements of the edge 13 are precisely scanned in this way.

Provided that a clean edge 13 having Web 12 of a material that absorbs light (e.g.

deep black color or a very rough surface), this may be the case digital sensing element 7 no longer work in the manner explained above, since the impinging Infrared light is not reflected. For this purpose, it becomes a reference surface 30 moved with the reflective layer carrying plate 29 into the work area. the Infrared lamps 33 then generate the infrared light 41 pulsating (scanning) in the in Fig. 8 by an arrow R indicated direction. Only from the one with the reflectivity layer bearing reference surface 30, light 42 is reflected back, which 3tp Again the exact position and the movements of the edge 13 are indicated.

In the principle of Fig. 7, the plate 29 can also be below of the work area, it will only be provided with an absorption surface be designed as a reference surface 30 and do not reflect the infrared light 41, so that the edge 13 is imaged with a very high contrast. The easiest way to do this be accomplished by giving plate 29 a reflective surface and has an absorbent surface, each in the correct position positioned below the work area.

If there is now a web 12 made of a material that has an edge course which is no longer suitable for optical scanning because, for example, increased If the thread ends protrude or if it is very jagged or frayed, then will the feeler arm 9a of the mechanical feeler member 9 is pivoted into its working position, in which it then rests against the edge 13 with the scanning flag 10.

The edge structure is unfavorable for the mechanical sensing element 9 irrelevant, since at the speed of the running tooth 12 this edge structure for the mechanical sensing element 9 a perfect edge 13 results. The antennae arm 9a of the mechanical sensing element 9 then shows the respective position of the edge 13, which is scanned by the digital sensing element 7 on the basis of the cover lug 11. It can proceed again so that the cover lug 11 is reflective, if the respective free area is light-absorbing, or that the cover flap 11 Is formed light-absorbing, while a reflective in the exposed area Reference surface 30 is arranged. However, this reference surface 30 must then go so far be below the web 12 so that they do not collide with the scanning flag 10 can. The digital sensing element 7 then scans the edge 13 only indirectly via the cover tab 11 or its reference edge. lEa the cover lug 11 immediately above the The area in which the web 12 is also located, the movements the edge 13 communicated practically unadulterated to the digital sensing element 7, so that no route over- or reduction has to be taken into account, but the recipient feel the exact extent of the edge movement very sensitively.

For simpler applications, the mechanical sensing element 9 also work together with conventional, electrical contacts in the support body 2, in which case the digital sensing element 7 can remain in function.

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Claims (26)

Edge sensing device claims 1. Edge sensing device for a running material web with which movements occurring transversely to the direction of web travel the edge can be tapped and converted into signals, and which a support body having at least one sensing element, characterized in that the sensing element (7) is a non-contact tactile element to which a mechanically tactile Sensing element (9) is arranged next to that the sensing element (7) when in a working position on the web edge (13) located mechanical sensing element (9J the web edge (13) indirectly via the mechanical sensing element (9) takes off, and that the mechanical Feeler element (9) can be moved from the working position into a passive position in which the Sensing element (7J the web edge (13) directly in reflection or in the light barrier principle takes off. 2. Edge sensing device according to claim 1, characterized in that that the non-contact sensing element (7J operate analog or digital of the probe element is. 3. Edge sensing device according to claim 1 or 2, characterized in that that the non-contact sensing element (7) from a ribbon-shaped light source (33) and one of several lined up, individually activatable receivers (36) existing receiver part, the longitudinal direction of the tape being transverse to the direction of travel of the web is aligned. 4. Edge sensing device according to claims 1 to 3, characterized in that that the non-contacting Fiihl member (7) - an infrared light emitting light source (33) contains. 5. Edge sensing device according to claim 4, characterized in that that the light source (33) consists of adjacent infrared lamps, and that the receiver (36) close, preferably zigzag with mutual overlap offset, lying next to each other. 6. Xanten feeler device according to at least one of claims 1 to 5, characterized in that the light source (33, and the receiver (36) approximately lie next to one another in the same plane and so inclined at an angle to one another are that there is an acute angle of reflection between them. 7. Edge sensing device according to at least one of claims 1 to 6, characterized in that the light source (33) and the receiver (36) in one Housing (38) are housed, which is t-permeable through an infrared disc (8) is covered. 8. Edge sensing device according to at least one of claims 1 to 7, characterized in that the light source (33) and the receiver (36) in the housing (38) arranged in tunnel-shaped tubes (39, 40) at a distance behind the disc (8J are. 9. Edge sensing device according to at least one of claims 1 to 8, characterized in that the receiver (36) is embedded in a printed circuit board (35) are to which the in the housing (38) in a Socket held light source (35) is connected to transmit current. 10. Edge sensing device according to claim 9, characterized in that that the circuit board (35) with the light source (33) and the receivers (36) can be removed is set in the housing (38). 11. Edge sensing device according to at least one of claims 1 to 10, characterized in that below the web (12) a reflection or Absorption surface (30) is provided for the light from the light source (33). 12. Ka ntenfühlvorrichtung according to at least one of claims 1 to 11, characterized in that the mechanical sensing element (9J a in the support body (2) pivotably mounted against a spring force effective in a pivoting direction Feeler arm (9a) is in the form of a one-armed lever. 13. Kanzenfüh Ivorrich device according to at least one of claims 1 to 12, characterized in that the feeler arm (9a) has a scanning axis (10) for the web edge (13) and an approximately tangential to the pivot axis (26, 28) lying cover flap (11) carries. 14. Edge sensing device according to at least one of claims 1 to 13, characterized in that the scanning lug (10) is integral with the covering lug (11) is formed and attached to the feeler arm (9a). 15. Edge sensing device according to at least one of claims 1 to 14, characterized in that the cover tab (11) is a reference edge for the has digital sensing element (7). 16. Edge sensing device according to at least one of claims 1 to 15, characterized in that the pivot bearing (5, 27) of the Feeler arm (9a) above the non-contact sensing element (7) and that in the working position of the mechanical sensing element (9) at least the cover tab (11) between the contactless working sensing element (7) and the web (12). 17. Edge sensing device according to at least one of claims 1 to 16, characterized in that on the support body (2) a material web (12) engaging under Support bracket (4) is provided. 18. Edge sensing device according to at least one of claims 1 to 17, characterized in that a limiting device in the pivot bearing (5) (18a) provided for the pivoting range of the feeler arm (9a) in its working position is. 19. edge sensing device according to claim 18, characterized in that that the limiting device (18a) has an extension (18) on a pivot shaft (28) of the sensor arm (9a), which has a stop (19) in both pivoting directions assigned. 20. Edge sensing device according to claims 18 and 19, characterized in that that the stops (19) in a recess / 19al one on the support body (2) around the Pivot axis rotatable element (15) are formed, and that a latching for the element (15) is provided, with which this in a working position of the Sensor arm (9a) defining the rotational position and in a passive position of the sensor arm (9a) defining rotational position can be fixed, in which the feeler arm (9a) over the support body (2) is held pivoted upwards. 21. edge sensing device according to claim 20, characterized in that that the latching consists of at least one spring-loaded ball (16, 16a) in the element (15) and at least one locking socket (17J in the pivot bearing (5)). 22. Edge sensing device according to at least one of claims 1 to 21, characterized in that an additional locking socket (17) in the pivot bearing (5) is provided, which defines a waiting position (W) for the sensor arm (9a), in which it pivots away from the web (12) to the underside of the support body (2) is held. 23. Edge sensing device according to at least one of claims 1 and 12 to 17, characterized in that the pivot bearing (27) with the sensor arm (9a) about a pivot axis (26) on the support body directed approximately vertically to the plane of the material web (2) is pivotable, and that in the pivot bearing (27) the sensor arm (9a) by another and the pivot axis (28) perpendicular to the pivot axis (26) can be pivoted into the passive position is. 24. Edge sensing device according to claim 17, characterized in that that in the support bracket (4J one held in sliding guide (14), a reflective and 1 or plate (29) having an absorbent reference surface (30) is provided is. 25. Edge sensing device according to part 24, characterized in that that the plate (29) has a grip point (31). 26. Edge sensing device according to the preceding claims, characterized characterized in that it is structurally integrated into an edge roller or a strip roller is incorporated in a ßahnführungvorrichtung.