US3599849A

US3599849A - Web registry control apparatus

Info

Publication number: US3599849A
Application number: US844260A
Authority: US
Inventors: John G Callan
Original assignee: Knox Inc
Current assignee: Knox Inc
Priority date: 1969-07-24
Filing date: 1969-07-24
Publication date: 1971-08-17
Anticipated expiration: 1988-08-17

Abstract

A detector (including, e.g., a U-shaped sensing head) for sensing departures of a portion of a travelling web, such as its edge, and initiating corrective action by adjusting equipment, wherein presence of the web within a detector nul zone indicative of a desired web edge position deflects a fluid jet at the web side of the nul zone which would otherwise operate adjusting equipment in one direction (e.g., which in turn operates the adjusting equipment), by being received in a passage on the opposite side of a web to produce a fluid jet therein for operating the adjusting equipment; and wandering of the web edge beyond the far side of the nul zone interrupts a jet deflecting means (e.g., another jet) which, unless interrupted, prevents a jet at the far side of the nul zone from operating adjusting equipment in the opposite direction. Sensing jets are used to operate directly fluid-operated valves controlling the webadjustment equipment.

Description

United States Patent Primary Examiner-Richard A. Schacher Assistant Examiner-Gene A. Church Attorney- Edgar H. Kent Sharon, Mass. 844,260

[21] Appl. No.

.mwm m w nd e w hmn e o i ffl ao n e gmw i euou m m a m f 000 m iet .m mm," n 3.1 c w m e d b e A flg :nd Te C At. news T SMh n w AhS m 9 k 7 o .m l ca 7hw .x w m u o JAKS de m dw. tS na FPA NH 247 [ii equipment, wherein presence of the web within a detector nul zone indicative ofa desired web edge position deflects a fluid jet at the web side of the nu! zone which would otherwise [54] WEB REGISTRY CONTROL APPARATUS 7 Claims Drawing Figs operate ad usting equipment In one direction (erg, which in turn operates the adjusting equipment), by being received in a passage on the opposite side of a web to produce a fluid jet therein for operating the adjusting equipment; and wandering of the web edge beyond the far side of the nu] zone interrupts Fieldoisearchuilllil..illiimlrlum"WM";

l C L n I ll] 2 0 555 ill a jet deflecting means (eg, another jet) which, unless interrupted. prevents a jet at the far side of the nul zone from [56] References Cited UNITED STATES PATENTS 4/1966 Jacobsen...'...............

operating adjusting equipment in the opposite direction.

226/22 (UX) Sensing jets are used to operate directly fluidoperated valves controlling the web-adjustment equipment.

3,504,834 4/1970 Guest ........t..t.t....

PATENTED AUG] 7 I9?! SHEET 1 OF 2 PATENTEU AUG] nan 3,599, 49

SHEET 2 I]? 2 FIG 2 55 FIG 4 55 FIG 5 55 WEB REGISTRY CONTROL APPARATUS This invention relates to apparatus for controlling registry of a moving web with equipment such as feed rolls operating on the web and, more particularly, to apparatus for detecting a lack of desired registry and for producing the requisite correctional action of adjustment equipment.

In control systems of the type to which the invention relates a detector is employed for sensing departures of a portion of a web, such as its edge, in a direction transverse to that of web movement. In some applications a web may move over a feed roll at a rate of hundreds, or even several thousands, of feet per minute and the position of the edge of the web may, if corrective action is not taken, deviate substantially from the desired registry with the roll. Many existing detectors have a relatively slow response time, must be located at a greater distance than is desirable from adjusting equipment, and tend to overcorrect for web departure. Others, which are more sophisticated and provide correction proportional to web departure, are correspondingly more complicated, bulky, and expensive.

It is an object of the present invention to provide a detector having an extremely short response time with apparatus that is simple, compact, reliable, and inexpensive.

Another object of the invention is to provide such a detector which continuously senses the position of the edge of the web, and wherein wandering of the web edge in either direction beyond a nul zone representing a desired position causes a fluid control jet to initiate corrective action by the adjusting equipment to return the edge to registry with the nul zone. A still further object of the invention is to provide such a detector wherein the adjusting equipment is operated by a fluid motor controlled by a valve operated oppositely and directly by said control jets.

The invention features in one aspect such a detector wherein the presence of the web edge in the nul zone deflects a fluid jet at the web side of the nul zone which would otherwise cause corrective action of the adjusting equipment and wherein wandering of the web edge beyond the far side of the nul zone interrupts a jet deflecting means which, unless interrupted, prevents a jet at the far side of the nul zone from causing corrective action of the adjusting equipment, this jet deflecting means being preferably another jet. Also, the invention features the use of sensing jets to operate directly a valve or valves controlling the web direction adjustment equipment, enabling extremely fast adjustment.

In preferred embodiments the detector has structure defining spaced upper and lower detector portions and an end portion defining a sensing gap at an edge of the web, the gap containing a nul zone and at either side thereof jets and receivers therefor defining operating zones of actuation of the webdirection correcting equipment.

Other objects, features, and advantages will appear from the following description of a preferred embodiment of the invention, taken together with the attached drawings thereof, in which:

FIG. 1 is a perspective view, partially in section, of a web, roller assembly, and a web-adjusting assembly with a sensing head constructed in accordance with the invention;

FIG. 2 is a bottom view, partially broken away, of the sensing head of FIG. 1;

FIG. 3 is an end view of the sensing head;

FIG. 4 is a sectional view of the sensing head, taken along line 44 of FIG. 3;

FIG. 5 is a different sectional view of the sensing head, taken along line 5-5 of FIG. 3;

FIG. 6 is a sectional view of the control valve for the webadjusting assembly of FIG. I with the valve in its intermediate closed position, and the piston shown schematically below; and

FIG. 7 is a sectional view of the control valve of FIG. 6 in one of its two open positions, also with the piston shown schematically.

FIG. 1 shows a web-guiding assembly 10 for controlling the lateral movement of web 12 having an edge 13, including a frame 15, pivotally secured by pivot block 16 and pivot pin 18 on support 19, and pairs of

pivot blocks

20, 21, for rotatably supporting web-guiding

rollers

22, 23. Frame 15 is connected to piston rod 24 through bracket 25 and rod clcvis 26, including pivot pin 27. Piston rod 24 is secured to and actuated by piston head 28, contained in actuating cylinder 30, which is pivotally secured through swivel joint 31 and pin 32 to bracket 33 on support 16, and which includes a first pressure chamber 34 and a second pressure chamber 36. A first air conduit 38 communicates with first pressure chamber 34 and a second air conduit 40 communicates with second pressure chamber 36.

Conduits

38 and 40 extend to three-position monostable valve 42, which is responsive, in a manner later described, to direct air under pressure through conduit 38 into chamber 34, while chamber 36 is opened to exhaust through conduit 40 or into chamber 36 through conduit 40 while chamber 34 is opened to exhaust through conduit 38, and thus to control the movement of piston head 28 and the axial movement of rod 24 secured thereto. Valve 42 is connected through conduit 44 to a control pressure (eg 10 to l5 p.s.i.) air supply source (not shown) which acts upon the valve and through conduit 45 to a system pressure (typically, p.s.i.) air supply source (not shown) which operates the piston head 28, both

conduit

44 and 45 extending through plate 46 to the positions shown in FIG. 6. Exhaust cylinders (e.g., sintered metal) 47 and 48 are respectively arranged to allow air to exhaust slowly from one of

chambers

34 and 36 when pressure is applied to the opposite chamber; the rate of exhaust from outlets 47, 48 (and therefore also the rate of movement of piston head 28) is controlled, e.g., by adjusting

screws

50 and 52.

Sensing head 55 is mounted on stationary support 56 and has a generally U-shaped cross section defined by upper and

lower portions

57, 58 and end portion 59, which enclose a sensing gap 60, through which the edge 13 of web 12 continually passes.

Control hoses

61 and 62 respectively connect

output ports

64 and 66 on sensing head 55 with

control ports

67 and 68 on valve 42, and

input hoses

70, 71, and 72 respectively connect an input air pressure supply (not shown) to

input ports

74, 76, and 78 on head 55, this supply being sufficient to produce, minimally a pressure of 1 inches of water through

lines

61, 62 to valve 42.

Referring to FIGS. 2-5, input port 74, disposed in upper portion 57, communicates with tubular inlet conduit 88, whereas output port 66, disposed in lower portion 58, communicates with tubular outlet conduit 90, both conduits extending parallel to the longitudinal axes of

portions

57, 58. Tubular nozzle 92, having orifice 94 and with longitudinal axis 96 extending transverse to the longitudinal axis of conduit 88, communicates with conduit 88, and directs a jet of air across sensing gap 60. A rectangular slot 98, defining an orifice 100, communicates, through tubular receiving inlet 102, which also lies on axis 96, with tubular conduit 90. These ports and conduits define one sensing zone of sensing head 55.

Input port 76 communicates with tubular inlet conduit I04, and therethrough with tubular nozzle 106, having a longitudinal axis 108 extending transverse to the longitudinal axis of conduit 104. Nozzle 106 is arranged to direct a jet of air radially across tubular hole 110, which is cut through lower portion 58 and is axially directed at sensing gap 60, at tubular receiving inlet 112, coaxial with nozzle 106, and communicating through tubular outlet conduit 114, with output port 64. Input port 78 communicates, through tubular inlet conduit 116, with nozzle 118, which is coaxial with tube 110, and is arranged to direct a jet of air across gap 60 into tube 110 to deflect the radial jet of air thereacross from nozzle 106 to inlet 112. These nozzles and ports define a second sensing zone.

Axes

96 and 108, in the embodiment shown, are parallel and about 0.25 inch apart, their forming nozzles being about 0.070 inch each in diameter.

Referring now to FIGS. 6 and 7, control valve has a substantially cylindrical central chamber 122, which is separated, respectively, from control inlets 124a and 124b, located at opposite ends of valve 42, by

disclike neoprene diaphragms

126a, 126b and restricted flow passages 128a, 128b. Control pressure conduit 44 communicates with chamber 122 through

passages

130a, 130b, and with

control pressure exhausts

132a, 132b, through restricted flow passages 128a, 128b, respectively.

Diaphragms

1260, 126b are arranged to deform inwardly and thereby close restricted

flow passages

1280, 128b, respectively, when the air pressure through control inlets 124a, 124b, respectively, is at least 1% inches water (0.05 p.s.i.).

Valve spool 134, of circular cross section, is slidably disposed for axial movement within chamber 122 and is centered by springs 136a, 136b, in the absence of external forces. Spool 134 has a central shaft 137, carrying cylindrical end portions 138a, 138b, which form a sliding seal between chamber 122 and

passages

1300, 130b, respectively.

Exhausts

47 and 48 are connected into chamber 122 through passages 140 and 142, respectively. Output (piston control)

ports

38 and 40 and system pressure inlet conduit 45 are connected into chamber 122 through

passages

144, 146, and 148 respectively. Spool 134 has two cylindrical lands 150 and 152, separated to define an annular space 154, which is sealed, by lands 150, 152, from passages 140, 142, respectively, and from

passages

144, 146, respectively, and open to inlet conduit 45, when spool 134 is centered as shown in FIG. 6. when spool 134 has moved longitudinally, space 154 permits passage 148 and hence inlet 45 to communicate with one of passage 144 or passage 146 depending upon whether spool 134 has moved to the left or to the right, whereas the other of passage 144 or passage 146 is allowed, by displacement of lands 150, 152, to communicate with one of

exhausts

47 and 48. (In FIG. 7, spool 134 is shown moved to the left of its FIG. 6 position.)

In operation, air is supplied to input

ports

74, 76, and 78 of sensing head 55 to produce air jets from

nozzles

92, 106, and 118, respectively. A first sensing zone, extending across gap 60, is defined by nozzle 92 and outlet orifice 102 (FIG. 5, on axis 96) whereas a second sensing mite, also extending across gap 60, is defined by nozzle 118 and tubular hole 110 (on axis 108, FIG. 2).

When web edge 13 is disposed in the nul zone between

axes

96 and 108 it interrupts the jet of air from nozzle 92 into gap 60; hence, the jet does not enter inlet 100, and there is no output at port 66 and hence no pressure through control port 68 on membrane 126b. Since the web does not, however, lie between nozzle 118 and tube 110, the jet flowing from nozzle 118 will divert the jet from nozzle 106 to receiving inlet 112, and hence there is no output at port 64 and no pressure through conduit 67 on membrane 1260. Control valve 42 will be centered in its closed position (FIG. 6) and the position of piston head 28 and, therefore, the orientation of frame 15, will be constant. However, if the web edge 12 begins to move out of the nu] zone away from axis 108 (out of sensing head 55), it will eventually allow the jet from nozzle 92 to enter orifice 102 and port 66, bending diaphragm 126b to close passage 1286. Control pressure from port 44 will therefore be diverted through passage 130b against cylindrical portion 138b, driv ing spool 134 to the left (FIG. 7). System air pressure will now be directed from port 45 through passage 148 into space 154 and passage l-i-l through conduit 38 into pressure chamber 34. At the same time pressure chamber 36 is exhausted through conduit 40, passages 146 and 142, and exhaust 48. Piston head 28 is therefore driven into chamber 36 and pulls piston rod 24 and bracket 25 to rotate frame 15 clockwise about pin 18. This causes an immediate adjustment of web edge 13 back into the nul zone of the sensing head, which again diverts the jet of air from nozzle 92, hence relieving pressure on diaphragm 126b, closing the valve and stopping rotation of frame 15. However, guide roller 22 will also divert the direction of movement of the web itself relative to the frame and edge 13 will continue to move into the sensing head until the diversion jet flowing from nozzle 118 into tube 110 is interrupted. This allows the jet from nozzle 106 to flow into inlet 112 and through port 64, bending diaphragm 126a to close passage 128a and drive spool 134 to the right. The pressure in chamber 36 is thereby increased, while chamber 34 is exhausted, and piston head 28 is driven toward cylinder 34, pushing piston rod 26 and sliding block 20 to rotate frame 15 back toward a neutral position, in the direction shown in FIG. 1, and web edge 13 back into the nul zone. The diversion jet will then be reopened, and stop further rotation of frame 15. An initial movement of web 13 into the sensing head (toward end portion 59), of course, initiates an opposite series of adjustments.

The jet of air from nozzle 92 widens and forms a cone as it crosses gap 60. Slot 98 is provided, having a cross-sectional area greater than the maximum cross-sectional area of the cone, for receiving the entire jet from nozzle 92, and hence preventing portion of it from deflecting along sensing head portion 58. [n the absence of slot 98, a part of this jet would be deflected along portion 58 and would prevent at least part of the diversion jet from nozzle 118 from entering tube 110, thus occasionally causing an output at port 64, even though no web material is interposed between nozzle 118 and hole 110.

The low pressure 1% inches 11,0 minimum) required to deform membranes 1260, 126k and thereby to close passages 128a and 12% and operate valve 42, together with the comparatively high system pressure (approximately p.s.i.) which is available to create a differential in pressure between

chambers

34 and 36 and thereby to adjust frame 15, results in a detecting system which is highly sensitive to movement of the web edge departing from proper registry with the

rollers

22, 23 of frame 15 and yet has an extremely low response time (approximately 20 milliseconds) in making adjustment. The width of the nul zone may be varied considerably depending upon operational requirements and since the system described responds so quickly to lateral movement of the web edge it is especially adapted to use where only a minimal departure from registry can be tolerated. Furthermore, since, in contradistinction to many existing detectors, lateral movement of edge 13 is minimal and, therefore, no lateral movement of sensing head 55 is required, head 55 may be located adjacent the adjustment equipment and even have valve 42 mounted upon it to provide extremely close coupling between head 55 and valve 42. As will be apparent to those skilled in the art, valve 42, as well as head 55, may be operated by other fluids than air. When other fluids are employed, the fluids which are exhausted through

exhausts

47 and 48,

output ports

64 and 66, and passages 132a and 1112b are recirculated for reuse.

Alternative methods of constructing the second zone, defined by

nozzles

106 and 118, and inlet 112 are also readily apparent. For example, for relatively thick webs a mechanical sensor could be used to detect these web movements, with an attached slide for interrupting a jet directed through the gap in a two-part system similar to that of the first sensing zone (nozzle 92 to inlet 98), so long as the web is in the nul zone. Move ment of the web out of the nul zone toward the second sensing zone would cause a hole through the slide to move into alignment with the jet, resulting in passage of the jet across the gap, its receipt by a proper inlet, and the transmission of a signal of the control valve.

Other embodiments will occur to those skilled in the art and are within the following claims.

What 1 claim is:

1. A detector for controlling the operation of a device for regulating registry of a travelling web with equipment operating thereon, said detector comprising web edge position sensing means having first and second operating zones and an intermediate nul zone,

first fluid jet discharging and receiving passages disposed adjacent said first operating zone,

second fluid jet discharging and receiving passages,

disposed adjacent said second operating zone, and

jet deflecting means disposed in said second operating zone,

said jet receiving passages communicating with said device and being arranged to operate said device when either of said fluid jet receiving passages receives a jet,

said first discharging passage being arranged to discharge a first jet across said first operating zone and into said first jet receiving passage in the absence of web interposed between said first passages,

said second jet discharging passage being arranged to discharge a second jet into said second jet receiving passage in the presence of web in said second zone,

said jet deflecting means constructed and arranged to divert said second jet from discharging into said second jet receiving passage in the absence of web in said second operating zone.

2. A detector according to claim 1 comprising structure defining spaced upper and lower detector portions and an end portion, said upper and lower portions defining a sensing gap at an edge of said web containing a nul zone, said fluid jet discharging and receiving passages being arranged to locate said first and second operating zones in said sensing gap on either side ofsaid nul zone,

3. A detector according to claim 2 wherein said jet deflecting means comprises a third fluid jet discharging passage disposed adjacent said second operating zone, arranged to discharge a third jet across said second operating zone into said second jet to divert said second jet from discharging into said second jet receiving passage in the absence of web interposed in said second operating zone 4. A detector according to claim 3 wherein said first jet discharging passage and said first jet receiving passage are disposed, respectively, in opposite ones of said upper and lower detector portions, and

said third fluid jet discharging passage is disposed in an opposite one of said upper and lower detector portions from said second fluid jet receiving and discharging passages.

5. A detector according to claim 4 wherein said first jet receiving passage includes an inlet jet slot of cross-sectional area sufficient to receive said first fluid jet across its entire cross-sectional area, whereby portions of said first jet are prevented from deflecting ofl said detector portion and diverting said third jet from said second jet.

6. A detector according to claim 4 wherein said first jet discharging passage and said third jet discharging passage are located in said upper detector portion.

7. Apparatus for controlling the operation of a device for regulating the registry of a travelling web with equipment operating thereon, said apparatus comprising a sensing device responsive to the movement of said web by more than a predetermined amount in first and second directions, said sensing device being arranged to produce a first fluid stream when said web has moved more than said predetermined amount in one direction and to produce a second fluid stream when said web has moved more than said predetermined amount in said second direction, and a three position valve directly controlled by said first and second fluid streams and arranged to energize said equipment to return said web in the opposite direction from said web movement, said valve having a closed position when said web is in registry with said equipment and first and second open positions respectively corresponding to said first and second directions of web movement, said valve being actuated between said closed position and one of said first and second open positions by said first and second fluid streams, respectively, and being arranged to energize said equipment to move said web in said opposite direction from said web movement when said valve is in one of said open positions.

Claims

1. A detector for controlling the operation of a device for regulating registry of a travelling web with equipment operating thereon, said detector comprising web edge position sensing means having first and second operating zones and an intermediate nul zone, first fluid jet discharging and receiving passages disposed adjacent said first operating zone, second fluid jet discharging and receiving passages, disposed adjacent said second operating zone, and jet deflecting means disposed in said second operating zone, said jet receiving passages communicating with said device and being arranged to operate said device when either of said fluid jet receiving passages receives a jet, said first discharging passage being arranged to discharge a first jet across said first operating zone and into said first jet receiving passage in the absence of web interposed between said first passages, said second jet discharging passage being arranged to discharge a second jet into said second jet receiving passage in the presence of web in said second zone, said jet deflecting means constructed and arranged to divert said second jet from discharging into said second jet receiving passage in the absence of web in said second operating zone.

2. A detector according to claim 1 comprising structure defining spaced upper and lower detector portions and an end portion, said upper and lower portions defining a sensing gap at an edge of said web containing a nul zone, said fluid jet discharging and receiving passages being arranged to locate said first and second operating zones in said sensing gap on either side of said nul zone.

3. A detector according to claim 2 wherein said jet deflecting means comprises a third fluid jet discharging passage disposed adjacent said second operating zone, arranged to discharge a third jet across said second operating zone into said second jet to divert said second jet from discharging into said second jet receiving passage in the absence of web interposed in said second operating zone.

4. A detector according to claim 3 wherein said first jet discharging passage and said first jet receiving passage are disposed, respectively, in opposite ones of said upper and lower detector portions, and said third fluid jet discharging passage is disposed in an opposite one of said upper and lower detector portions from said second fluid jet receiving and discharging passages.

5. A detector according to claim 4 wherein said first jet receiving passage includes an inlet jet slot of cross-sectional area sufficient to receive said first fluid jet across its entire cross-sectional area, whereby portions of said first jet are prevented from deflecting off said detector portion and diverting said third jet from said second jet.