US2871013A - Web guide - Google Patents

Description

Jan. 27, 1959 F. J. MARKEY WEB GUIDE Filed April 3, 1956 2,871,013 Patented Jan. 27, 1959 WEB GUIDE Frank J. Markey, Hammond, Ind., assignor to GPE Controls, Inc., Chicago, 111., a corporation of Illinois Application April 3, 1956, Serial No. 575,808 12 Claims. (Cl. 271-26 The present invention relates to detection of the lateral positions of the edges of longitudinally traveling webs, and to web guiding, wherein the transverse position of a longitudinally traveling web is maintained in preselected relation to apparatus to or from which the web is being fed, by relative transverse shifting of the apparatus and web to correct departures from the correct, preselected transverse positional relation.

. More particularly, the invention relates to that general type of web edge position detecting and indicating, and web guiding, in situations wherein the web is of varying width. Heretofore quite satisfactory apparatus has been developed for use with webs of regular or only slightly varying widths operating by detection of the lateral position of a single web edge. In situations wherein the web width may vary to any substantial extent, such a single edge-detectingdevice may be wholly unsatisfactory. The

present invention is based on the concept of detecting and indicating the position of the transverse center line of the web,and, in guiding, it is extended to embrace maintenance of the web center line in a preselected path by automatically shifting the web, or, in case the web is being fed to or from apparatus that performs some operation upon it, relatively shifting the apparatus and web, to correct variance of the web center line from its preselected path or to correct variance from the proper transverse positional relation between theweb and apparatus.

This mode of operation is accomplished by continuously detecting the lateral positions of both of the web edges, and developing detector signals the magnitudes of which vary continuously and proportionally with distances of lateral change in the positions of the web edges, By this type of detection and signal development, the magnitudes of the detector signals afiord continuous indication of the distances by which the different web edges are spaced from a preselected reference point between and from which the detectorsare symmetrically spaced. Consequently it has capacity for detecting asymmetric spacing of the two web edges fromthe reference point, whether it be caused by lateral shift of the web, or by change of the position of one or both web edges without lateral shift of the web as a whole, the latter being a consequence of an asymmetric variation in the web width. On the other hand, if a change in web width is symmetrical, the magnitudes of the detector signals will change equally. This type of detection affords the possibility of direct and continuous automatic comparison of the detector signal magnitudes, and from them developing a resultant signal of which the magnitude represents degree of. unequal spacings of the different web edges from the intermediate reference point, or variance from theweb. centerline from its preselected path, and consequently the signal may be used either for indicating purposes alone, or as a control signal to actuate servo mechanism arranged to reestablish the web center line in its correct path. 7. t

Heretofore, certain web guiding equipment has embodied paired webedge detectors respectively disposed variation of web edge lateral positionrepresenting signals,

comparison of which serves to indicate presence and degree of variance of the two web edges from symmetric spacing from an intermediate reference point in a preselected location.

. In the accompanying drawings:

Fig. 1 is a somewhat schematic plan of a web guiding system embodying the invention.

Fig. 2 is an enlarged section on line 22 of Fig. 1.

In the arrangement shown in Fig. 1, the apparatus to which a web 6 is fed longitudinally, from a supply roll 7, and which apparatus performs an operation on the web, is shown as a slitter 8, comprising. one or more rotary knives such as shown at 9 mounted on a power shaft 10 in suitable number and spacing to perform the required division of web 6. Shaft 10 is mounted on stationary bearing assemblies 11. In the arrangement shown, roll 7 is supported on a suitable carriage 13arranged for adjusting movement in directions extended transverse to the web 6, for example by elongate slots 14 wherein station ary guide pins 15 are slidably engaged. A power unit 16 is provided for moving base 13 and roll-,7, forthe purpose of transversely positioning web 6, that is, for transverse adjustmentwof its path to apparatus 8, unit 16 being shown as a hydraulic piston and cylinder assembly. Operation of unit 16 is controlled by. a hydraulic relay regulator 17, having a control element that is movable from a neutral position wherein unit 16 is maintained out of operation, in opposite directions respectively to operate unit 16 in reverse directions, thereby to accomplish adjustment in opposite directional senses of the transverse relation between the feed path of web 6 and apparatus 8.

Regulator 17 is shown as a conventional jet pipe device of which the movable control element 18 comprises a pipe that is pivoted for swinging about an axis 19, and that has an end orifice at 24) for discharging at high velocity an axial stream or jet of pressurized liquid delivered to it through a supply connection 21. According to the angular position of the jet pipe, its discharge orifice registers more or less with the different ones of a pair of receiver ports 22 that are closely spaced in the directions of its swing path, and which respectively are connected to the different ends of the cylinder 23 of power unit 16. In the neutral position of member 18, discharge orifice 20 is in equal registration with ports 22, so that equal pressures are developed in the respective ends of the cylinder 23, but upon swinging of member 18 from its neutral position, unequal registration of the discharge orifice with the different ports 22 results in development of a pressure differential. acrossthe piston 24 of the power unit 16,- resulting in operation of unit 16 to shift. carriage 13 and roll 7, thereby transversely shifting web 6 and accomplishing the relative adjustment of the web path and apparatus 8.

r Web 6 is shown exaggeratedly as having irregularly varying width, due to irregular edges 25, 26. The present invention is directed primarily to the problem of maintaining the center line, indicated at; 27, of such a web in a preselected path having a preselected transverse positional relation to apparatus such as slitter 8. Inherently apparatus embodying the inventionwill operate to correct the transverse shifting that normally occurs in web feeding, irrespective of regularity or irregularity of Web-width, such as maybe caused, for example, by telescopic formation of the supply roll, lateral inequality in tension, and so on.

In accordance with the invention, a pair of web edge lateral position detectors 29, 30 aremounted in fixed tinuously and proportionally in response to variation in the-lateral positions of the web edges 25, 26 which respectivelythe detectors'are positioned to sense. Preferably the detectors 20, 30 are of the type shown in Fig. 2, comprising a delivery structure 34 and a receiver structure 35, which are spaced apart inopposed, facing relation to provide between them-a throat 36 for passage ofthe marginal portion of the web. Structure 34'is provided with a nozzle slot 37 for discharge of a sheet-like jet of air thelength-of which-is extended transverse to the' web edge that it senses, and structure 35 with a receiver slot 38 registered with nozzle slot 37 across throat 36, for reception of so much of the air jet as is unintercepted by the marginal portion ofthe web, whereby the magnitudeofpressure developed in an internal chamber 39 of receiver structure 37 varies as a function of the lateral position ofthewebedge and continuously corresponds to that position. That pressure magnitude, which is used asa signal, also represents the spacing of the web edge from any preselected reference point spaced from the detector transversely of the web andinwardfrorn the location of the detector, and consequently-may be considered as indicating'the 'spacing of the web edge from a reference line that-has been selectedas the correct path to be followed by'the center line of the web as it travels to the apparatus. Since detectors 29, 30 respectively are disposed to sense the lateral positions-of the ditferent web edges 26, 27, or,

as indicated, the-distances that those different web edgesare spaced from a line preselected as the correct path for the web center line, comparison of the positions or distances-represented by the signals developedby the respective detectors will indicate existence, sense and magnitude of differences in those spacings. In accordance-with the invention, these spacing distances are automatically and continuously compared, and from them is developed an indicating or control signal that continuously and proportionally corresponds to the relationship of the distances spacing the different web edges from the preselected center line path.

Conveniently a translating device may be arranged to perform this comparison function and to set the control element 18 in correspondance to the resultant. The fluid pressure signal detecting system described above particularly' lends itself to this type of arrangement. In the illustrated system, the translator device comprises a force balance assembly, generally. designated 41. It comprises a pair of expansible chamber devices, shown as diaphragm assemblies 42, 43, the chambers of the different ones of which are connected respectively to the receiver structure signal pressure chambers 39 of detectors 29, 30 by signal pipes 4-4. The diaphragms d5, d6 of assemblies 42, 43 are mechanically linked to control element 18 to exert oppositely thereon the forces developed by the diaphragms, which forces correspond to the signal pressures developed by the detectors 29, 3t and respectively exerted in the chambers of assemblies 42, 43. Centering springs 47 maybe provided.

It is unavoidable in a system of the kind disclosed that response of two detector-translator systems, such as 29, d2, 45- and 3t), 43, 46 will be different, that is, output force changes by the two-systems in response to" equal lnteral changes in web edge'positio'ns will be of ditferent magnitudes. One of the principal advantages of a jet pipe regulator, particularly in web guide applications, is extreme sensitivity to signal force variations, and rapidity of response of the power unit. These two factors necessitate, in the system of Fig. 1, provision of readily adjustable means for compensating response differences of the two detector-translator systems that detect and compare the positions of the two web edges, to provide indication of difierences in their spacings from an intermediate reference point, and development of a. signal the magnitude and sense of which correspond" respectively todegree and direction of displacements of the web center line from a preselected path having a definite transverse positional relation to apparatus to or from which the Web is being fed.

Such means is shown in the form of a so-called ratioslider assembly 51. This assembly comprises a lever 52 interposed in the linkage mechanism for transferring force to regulator control element 18 from one of the, translators, here diaphragm 45, lever 52 being pivoted for swinging about an axis parallel to axis 19. A slider 53' for transferring force from lever 52 to control element 18 is adjustable along the lengths of members 18,. 52, so that the effective lever arms through which are oppositely exerted and compared, the forces exerted by diaphragms 4-5, 46, may be inversely varied. Thereby the ratios of response in degree angular movement of control element 18 to distances of lateralshift of the difierent web edges 25, 26, may be adjusted and equal ized, to overcome the noted unavoidable response differ ences' of systems 29, 42, 45 and 30, 43,. 46. Diaphragms 45, 46 are connected respectively to lever 52 and to control element 18 by thrust links 54. I,

It will now be seen that, with ratio slider member 5-3.

so positioned that equal forces are oppositely exerted: on member 18 while equal lengths of the detector re-- ceiver ports 33' are exposed to jet streams delivered from the nozzle slots 37, and with marginal portions of a web.

6* traveling through the detector throats 38, any departure of the web edges, from symmetrical spacing. fromthe preselected web center line path, from which the detectors are symmetrically spaced, and whether causedby lateral shift of the web asa whole or by variation in the webaction will continue until the web center line has been registered with its preselected path, at which time the receiver port slots 38 will be equally masked, resulting in return of member 18 to its neutral position and termination, of relay operation.

I claim: 7

1. Meansv for detecting andindicating the lateral position of the center line of a longitudinally traveling webthe lateral positions of the edges of which may shift either incorresponding directions as a consequence of lateral movement of the web or relative to each other as a consequence of varying web width, said means comprising a first we-b edge detector arranged for sensing the lateral position of a first one of the edges of said web and. developing a first signal the magnitude of which varies continuously and proportionally with degree of change in the lateral position of said first web edge, a second web edge detector arranged laterally opposite said first" detector' for sensing the lateral position of the otheredge of said web and developing a second signal the magnitude of which varies continuously and proportionally with degree of change in the lateral-position of said other edge, and summarizer means coupled with both said detectors and arranged to'compare the magnitudes of said first and second signals andto produce a third signal the magnitude of which continuously and proportionally varies with the difference between the magnitudes of said first and second signals. a

2. Means for detecting and indicating the lateral position of the center line of a longitudinally traveling web the lateral positions of the edges of which may shift either in corresponding directions as a consequence of lateral movement of the web, or relative to each other as a consequence of varying web width, said means comprising a pair of fixed web edge lateral position detectors spaced apart across the path of the web, each of said detectors being arranged to sense the position of a different one of said web edges and to develop a signal the magnitude of which continuously and proportionally varieswith degree of change in the lateral position of the web edges the position of which it is arranged to sense, andsummarizer means coupled to both said detectors and arranged to compare the magnitudes of said signals in senses such that changes in the magnitudes of the different signals corresponding to shifts of the different web edges in opposite directions are opposed to each other and changes in their magnitudes corresponding to shifts of both web edges in the same direc-,

tion aid each other, and said summarizer means being arranged to produce a final signal the magnitude of which continuously and proportionally varies with the difference between the magnitudes of the flIStIlZWO said signals. 3. Means according to claim 2, wherein said detectors are of pneumatic type, arranged to produce signal pressures that comprise said first and second signals, and wherein said summarizer means comprise an expansible chamber assembly including movable wall structure subjected to said signal pressures, and an output member movable by said wallstructure to a position corresponding to the difference in magnitudes of said signal pressures.

4. Means according to claim 2, wherein said detectors are of pneumatic type, arranged to produce signal pressures that comprise said first and second signals, and arranged to vary the magnitudes of the different said signal pressures in the same senses in response to shift of the respective web edges in opposite directions and to vary the magnitudes of the different said pressures in opposite senses in response to shift of the respective web edges in the same directions, and wherein said summarize means comprise an expansible chamber assembly including movable wall structure subjected to said signal pressures and an output member connected thereto and positionable thereby in correspondence to the difference in magnitudes of said signal pressures.

5. Means according to claim 2, wherein said detectors are of pneumatic type, arranged to produce signal pressures that comprise said first and second signals, and

arranged to vary the magnitudes of the different saidsignal pressures in the same senses in response to shift of the respective web edges in opposite directions and to vary the magnitudes of the different said pressures in opposite senses in response to shift of the respective web edges in the same directions, and wherein said summarizer means comprise a pair of expansible chamber devices each connected with a ditferent one of said detectors for exertion within it of the signal pressure developed by that detector, each said device having a movable wall partly enclosing its said chamber, a movable member, and a mechanical transmission system connecting said member to each said wall for positioning the member in correspondence to the difference in magnitudes of the different said signal pressures.

6. Means according to claim 2, wherein said detectors are of pneumatic type, arranged to produce signal pressures that comprise said first and secondsignals, and arranged to vary the magnitudes of the different said signal pressures in the same senses in responsp to shift of the respective web edges in opposite directions and to vary the magnitudes of the different said signal pressures inopposite senses in response to shift of the respective web edges in the same directions, and wherein said surnmarizer means comprise a pair of expansible chamber devices each having a chamber connected with a different one of said detectors for exertion in the chamber of the signal pressure developed by that detector, and a movable wall partly enclosing said chamber, said movable walls ot the different expansible chamber devices being arranged in spaced opposition, a movable member positioned between said movable walls, mechanical linkages connecting the diiferent said walls to said member for positioning the latter in correspondence to the difference in magnitudes of said signal pressures, and at least one of said linkages including an adjustable relative motion mechanism providing for adjustment to compensate differences in the characteristics of responses of the respective expansible chamber devices toequal shifts of the said respective web edges.

7. In a system for delivering a longitudinally traveling web to apparatus for performing an operation thereon and including mechanism for relatively shifting the apparatus and web in directions extended transverse to the latter; means for maintaining the center line of the web in a preselected path that has a preselected transverse positional relation to the apparatus, comprising a pair of web edge position detectors disposed in fixed relation to said apparatus and spaced across the web path in symmetrical spacing from said-center line path and in dispositions for respectively detecting the lateral positions of the diiferent web edges, each said detector being arranged to develop a detector signal the magnitude of which varies continuously and proportionally in response to changes in the spacing from said center line tudes indicative of different spacings of said web edges from said center line path to accomplish relative shifting of said apparatus and web in a sense to eliminate the difference in said spacings.

8. Means in a system for delivering a longitudinally traveling web to apparatus for performing an operation thereon and including mechanism for relatively shifting the apparatus and web in directions transverse to the latter, and said mechanism having a control element that is movable in opposite directions from a neutral position wherein said mechanism is maintained idle, respectively to actuate said mechanism to relatively shift said weband apparatus in opposite directional senses; said means being arranged to maintain the center line of the web in a definite path having a preselected transverse positional relation to said apparatus, and comprising a pair of web edge position detectors disposed in fixed positional relation to said apparatus and in symmetrical spacing relative to said center line path, the different said detectors being disposed to sense the lateral positions of the different edges of the web and each being arranged to develop a detector signal the magnitude of which varies continuously and proportionally in correspondence to changes in spacing from said center line path of the Web edge the position of which it detects, a translator device coupled to both said detectors, connected with said control element and responsive to both said detector signals to maintain said element in its neutral position while magnitudes of said signals correspond to equal spacings of the web edges from said center line path, and upon said signal magnitudes becoming indicative of difference in said spacings to move said control element in the direction to actuate 9. Meansaceording to claim 8-, wherein said detectors are arranged to develop fluid psessure detector signals and said translator device comprises a force balance assembly having a pair of expansible chambers respectively coupled to the diiferent said detectors for developing forces of magnitudes corresponding to said signals, movable wall structure partly enclosing said chambers, and linkage mechanically connecting said movable wall structure to said control element.

10. Means-according to claim 9, wherein said control element is elongate and pivoted for swinging movement, andsaid linkage includes an adjustable force-distance selecting connection betweensaid element and the. wall structure enclosing one of said chambers.

ll. Means according to claim 8, wherein said detectors are arranged to develop fluid pressure detector signals both of which vary in the same one sense in-response to increase of spacings of the web edges from said center line path and in the same opposite sense in response to decrease in said spacings, and said translator device comprises a pair of expansible chamber assemblies respectively coupled to the diiferent saiddetectors for translating the different detector signals to forces of corresponding magnitudes, and said means including linkage con necting the movable walls of said assemblies with said control element for opposite exertion thereon of the forces developed by the different said assemblies.

12. Means according. to claim 8, wherein said detectors are arranged'to develop fluid pressure detector signals both of which vary in the same one sense in response to'increase of spacings of the diflferent web edges from said center line path and in the same opposite. sense inresponse to. decrease. in said spacings, said control element comprises a member that is pivoted for swinging, said translator comprises a pair of expansible motor assemblies respectively coupled to the diifererit said detectors fortranslating said detector signals to forces of correspondingmagnitudes, said linkage comprises a link age mechanically connecting the-movable wall of one said assembly to said control element for exerting thereon and in one of its directions of swing the force developed References Cited in-the file of this patent UNITED STATES PATENTS 2,539,131 Gundersen et a1. Jan. 23, 1951 2,666,639 Frommer Ian. 19,. 1954 2,726,858 Cherigie Dec. 13, 1955 2,735,630 Ziebolz Feb. 21, 1956

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