Patent Application
20150345996
1. Field
The present specification generally relates to apparatuses and methods for measuring an angle between a web of material and a conveyance direction.
2. Technical Background
Thin, flexible glass webs can be used in various applications, including so-called “e-paper,” color filters, photovoltaic cells, displays, OLED lighting, and touch sensors. The glass for such substrates can be quite thin, typically less than about 0.3 mm. The processing of the substrates can be performed on an individual glass sheet basis, or most efficiently, by conveying the substrate as a long glass web, which can be wound on a roll or spool. Such methods include conveying newly formed glass webs to a glass manufacturing apparatus, processing the glass web, and then winding the glass web onto a take-up roll. Alternatively, the glass web can be singulated into discrete components or sheets instead of the final winding onto a take-up roll.
One drawback to processing glass webs and winding the glass webs on a take up roll is the brittleness of the thin glass web. Specifically, mechanical contact of the glass web during handling can lead to damage, including scratches, chipping, and fracture. The problems may be exacerbated if the web is misaligned during processing and winding, resulting in the glass webs being discarded, thereby increasing manufacturing costs and reducing production yields.
Accordingly, there is a need for apparatuses and methods to determine angular misalignment as the glass webs are conveyed through the manufacturing operations.
In one embodiment, an angle measurement device for measuring an angle between a web of material and a conveyance direction includes a mounting bracket, a shaft rotatably coupled to the mounting bracket such that the shaft is rotatable with respect to the mounting bracket, a caster portion coupled to a first end of the shaft and positioned to contact a surface of the web of material being drawn over a web conveyance pathway, where the caster portion is spaced apart from an axis of rotation of the shaft, and an angular displacement sensor coupled to the mounting bracket and positioned to detect an angular orientation of the shaft with respect to the mounting bracket, where the angular displacement sensor outputs a signal indicative of the angular orientation of the shaft with respect to the mounting bracket.
In another embodiment, a method for measuring an angle between a web of material and a conveyance direction of the web of material includes directing the web of material in the conveyance direction on a web conveyance pathway, contacting a surface of the web of material with a caster portion of an angle measurement device, where the caster portion is connected to a shaft that is rotatably coupled to a mounting bracket of the angle measurement device, the caster portion is spaced apart from an axis of rotation of the shaft, and contact between the caster portion and the web of material rotates the shaft with respect to the mounting bracket, detecting an angular orientation of the shaft with respect to the mounting bracket about the axis of rotation of the shaft, and determining an angle between the web of material and the conveyance direction based on the angular orientation of the shaft with respect to the mounting bracket.
In yet another embodiment, an angle measurement device for measuring an angle between a web of material and a conveyance direction includes a mounting bracket, a shaft rotatably coupled to the mounting bracket such that the shaft is rotatable with respect to the mounting bracket, a coupling member portion coupled to a first end of the shaft, where the coupling member portion includes a hinge, a caster portion coupled to the coupling member portion and positioned to contact a surface of the web of material being drawn over a web conveyance pathway, where the caster portion is spaced apart from an axis of rotation of the shaft, the caster portion pivots with respect to the mounting bracket about an axis of rotation of the hinge, and the caster portion is rotatable about an axis of rotation perpendicular to the axis of rotation of the shaft, and an angular displacement sensor coupled to the mounting bracket and positioned to detect an angular orientation of the shaft with respect to the mounting bracket, where the angular displacement sensor outputs a signal indicative of the angular orientation of the shaft with respect to the mounting bracket.
Additional features and advantages of the embodiments will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.
Reference will now be made in detail to embodiments of apparatuses and methods for measuring an angle between a web of material and a conveyance direction as the web of material is conveyed through various manufacturing operations. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.
The phrase “communicatively coupled” is used herein to describe the interconnectivity of various components of the angle measurement device and means that the components are connected either through wires, optical fibers, or wirelessly such that electrical, optical, and/or electromagnetic signals may be exchanged between the components.
While glass is generally known as a brittle material, inflexible and prone to scratching, chipping and fracture, glass having a thin cross section can in fact be quite flexible. Glass in long thin sheets or webs can be wound and un-wound from rolls, much like paper or plastic film. However, even though glass can be made flexible, it retains its brittle characteristic, and can be damaged by contact.
Maintaining lateral alignment of the glass web as the glass web travels through glass manufacturing equipment may be complicated by misalignment of components of the glass manufacturing equipment. Further, instabilities, perturbations, vibrations, and transient effects that may exist in manufacturing environments or in processing and handling equipment may cause intermittent or extended misalignment of the glass web in the lateral direction to occur. In extreme cases, lateral misalignment of the glass web may lead to fracture.
For example, alignment (or misalignment) between the glass web and glass manufacturing equipment may affect the quality of the processes carried out by the glass manufacturing equipment. In particular, some glass webs are processed by continuously separating thickened edge beads from the glass web. During the bead removal process, the thickened edge beads are separated from the glass web, and the thickened edge beads are conveyed down alternate paths than the glass web. The thickened beads impart stress on the glass web at the points where the glass web is separated from the thickened edge beads. The relative angles between the glass web and the separated thickened edge beads affects the stress at the separation points, and misalignment of the glass web entering the bead separation process can increase the stress at the separation points, potentially causing web breakage. Further, misalignment between the glass web and the bead removal process may prevent the edge beads from being accurately removed from the glass web, potentially resulting in significant manufacturing losses as portions of the glass may be discarded.
The apparatuses and methods described herein provide for measuring an angle between a web of material and a conveyance direction as the web is fed through manufacturing and processing equipment. By measuring the angle between the web of material and the conveyance direction, misalignment of the web of material may be identified so that the misalignment of the web of material may be corrected.
Referring now to
In the embodiment of the web conveying apparatus 100 depicted in
While
In embodiments, the web conveying apparatus 100 may optionally include a conveyance mechanism which provides a tractor force to the glass web. For example, in the embodiment of the web conveying apparatus 100 depicted in
In the embodiments described herein, the conveyance mechanism of the web conveying apparatus 100 is utilized to draw the glass web 102 in a conveyance direction 107 on a web conveyance pathway 10. As the glass web 102 is drawn in the conveyance direction 107, an angle between the glass web 102 and the conveyance direction 107 is measured by an angle measurement device 101.
Still referring to
As depicted in
The shaft 112 of the angle measurement device 101 is rotatably coupled to the mounting bracket 110, such that the shaft may rotate with respect to the mounting bracket 110 about an axis of rotation 115 of the shaft 112. In embodiments, the shaft 112 may be coupled to the mounting bracket 110 by the angular displacement sensor 114, as will be described in greater detail herein. Alternatively or additionally, the shaft 112 may be coupled to the mounting bracket by a bearing assembly (not depicted) so that the shaft 112 freely rotates with respect to the mounting bracket 110. The axis of rotation 115 of the shaft 112 may be generally perpendicular to the web conveyance pathway 10.
In embodiments, the angle measurement device 101 includes a trailing arm assembly 116 coupled to the shaft 112. The trailing arm assembly 116 includes a caster portion 111, an arm portion 125, and a coupling member portion 118. The arm portion 125 is coupled to the caster portion 111 and the coupling member portion 118. The coupling member portion 118 is coupled to the shaft 112. The arm portion 125 spaces the caster portion 111 apart from the axis of rotation 115 of the shaft 112, as schematically depicted in
Referring to
The hinge 119 of the coupling member portion 118 allows the caster portion 111 to pivot with respect to the mounting bracket 110 about the axis of rotation 120 of the hinge 119 and, in particular, allows the caster portion 111 to move with respect to the mounting bracket in the +/−Z-direction of the coordinate axis depicted on
Still referring to
In embodiments, the rotating element of the caster portion 111 is a wheel 122, which has an outer circumference 123. The wheel 122 of the caster portion 111 may be rotatable with respect to the trailing arm assembly 116 about the axis of rotation 121 of the caster portion 111. The outer circumference 123 of the wheel 122 of the caster portion 111 may be positioned to contact the top surface 104 of the glass web 102. As described above, because the wheel 122 of the caster portion 111 is rotatable with respect to the trailing arm assembly 116, reaction forces as a result of the contact between the top surface 104 of the glass web 102 and the outer circumference 123 of the wheel 122 of the caster portion 111 may be minimized, which in turn minimizes damage to the glass web 102.
Alternatively, the caster portion 111 may comprise a ball or sphere (not depicted) or a similar rotating element positioned to contact the top surface 104 of the glass web 102. In yet another alternative embodiment, the caster portion 111 may comprise a stationary element, such as a stylus coupled to the arm portion 125. The stylus may be positioned to contact the top surface 104 of the glass web 102. The stylus may be formed from a soft and/or flexible material so that contact between the stylus and the top surface 104 of the glass web 102 does not damage the glass web 102.
Still referring to the embodiment of the angle measurement device 101 depicted in
In one embodiment, the coupling member portion 118 may further comprise a biasing member 126 coupled to the hinge 119. The biasing member 126 biases the caster portion 111 and the arm portion 125 in the +Z-direction toward the mounting bracket 110, as depicted in
As used herein, the term “apparent mass” is used to describe a mass corresponding to an observed force imparted by an object as a result of gravity. For example, in embodiments where the coupling member portion 118 includes a hinge 119, a mass of the caster portion 111 and the arm portion will impart a force on the top surface 104 of the glass web 102. In embodiments of the coupling member portion 118 which further include a biasing member 126, the biasing member 126 at least partially counteracts the effect of gravity on the caster portion 111, reducing the force imparted on the top surface 104 of the glass web 102. The reduced force corresponds to a reduced apparent mass, i.e., the mass that would be expected corresponding to the observed force imparted on the top surface 104 if no biasing member were present. In embodiments, the biasing member 126 biases the arm portion 125 and the caster portion 111 in the +Z-direction such that the apparent mass of the caster portion 111 is less than the actual mass of the caster portion 111. In embodiments not including a biasing member 126, the apparent mass of the caster portion 111 is equivalent to the actual mass of the caster portion 111.
In embodiments, an apparent mass of the caster portion 111 may be less than or equal to about 20 grams. In other embodiments, an apparent mass of the caster portion may be less than or equal to about 15 grams. By limiting the apparent mass of the caster portion 111, the force imparted on the top surface 104 of the glass web in the +/−Z-direction as a result of gravity may be similarly limited, thereby reducing damage to the top surface 104 of the glass web 102.
Still referring to
In embodiments, the angular displacement sensor 114 of the angle measurement device 101 may be communicatively coupled to a control unit (not depicted) and configured to output electronic signals to the control unit indicative of the angular orientation of the shaft 112 with respect to the mounting bracket 110. The control unit may include software and/or hardware to receive the electronic signals from the angular displacement sensor 114 and determine the angular orientation of the shaft 112 with respect to the mounting bracket 110.
Turning now to
Referring to
In embodiments, the angular displacement sensor 114 detects the angular orientation of the shaft 112 with respect to the mounting bracket 110, and outputs an electronic signal indicating the angular orientation of the shaft 112 with respect to the mounting bracket 110. The electronic signals from the angular displacement sensor 114 may be used to adjust the position of the glass web 102 as described in co-pending U.S. patent application Ser. No. ______ (Attorney Docket No. 24922 PA), which is assigned to Corning, Inc.
Referring now to
The thickened edge bead 133b may have a centerline 144 that evenly bisects the thickened edge bead 133b in a width direction of the thickened edge bead 133b. Similarly, the thickened edge bead 133c may have a centerline 145 that evenly bisects the thickened edge bead 133c in the width direction. As the thickened edge bead 133b is drawn over the web conveyance pathway 10b which is different than the web conveyance pathway 10a of the glass web 102, an angle between the centerline 144 of the thickened edge bead 133b and the centerline 143 of the glass web 102 may create stress at the separation point 108. Specifically, as the angle between the centerline 144 of the thickened edge bead 133b and the centerline 143 of the glass web 102 increases, the stress at the separation point 108 increases. Similarly, as the thickened edge bead 133c is drawn over the web conveyance pathway 10c, an angle between the centerline 145 of the thickened edge bead 133c and the centerline 143 of the glass web 102 may create stress at the separation point 109. As the angle between the centerline 145 of the thickened edge bead 133c and the centerline 143 of the glass web 102 increases, stress at the separation point 109 increases. High stress at the separation points 108 and 109 may lead to uncontrolled separation of the thickened edge beads 133b and 133c from the glass web 102 and fracture of the glass web 102.
To measure the angle between the centerline 144 of the thickened edge bead 133b and the centerline 143 of the glass web 102, a first angle measurement device 101a may be positioned to contact the top surface 104 of the glass web 102, and a second angle measurement device 101b may be positioned to contact a top surface of the thickened edge bead 133b. Similarly, to measure the angle between the centerline 145 of the thickened edge bead 133c and the centerline 143 of the glass web 102, the first angle measurement device 101a may be positioned to contact the top surface 104 of the glass web 102, and a third angle measurement device 101c may be positioned to contact a top surface of the thickened edge bead 133c. By measuring the angle between the centerlines 144 and 145 of the thickened edge beads 133b and 133c and the centerline 143 of the glass web 102, angular positions of the centerlines that may cause high stress at the separation points 108 and 109 may be identified and corrected.
Referring now to
The delivery vessel 225 supplies the molten glass 226 through a downcomer 230 into the FDM 241. The FDM 241 comprises an inlet 232, a forming vessel 235, and a pull roll assembly 240. As shown in
While a fusion draw machine as described herein may be utilized to form the glass web 102, other processes and methods of forming a glass web are contemplated. For example and without limitation, the glass web 102 may also be formed using a “redraw” process or using a glass float method. In the “redraw” process, heat may be applied to a surface of a “preform” glass sheet (not depicted). As the surface of the “preform” glass sheet is heated, the “preform” glass sheet may be drawn to reduce a thickness of the “preform” glass sheet to form the glass web 102. In the glass float glass method, molten glass may be “floated” over a bed of molten metal (not depicted). As the molten glass floats over the molten metal, the molten glass spreads across the molten metal to form a glass ribbon (not depicted), where the glass ribbon has a substantially uniform thickness. The glass ribbon may then be cooled to form the glass web 102.
Referring back to
Accordingly, as the glass web 102 exits the pull roll assembly 240 in the conveyance direction 107, the glass web 102 is brought into contact with the angle measurement device 101. The angle measurement device 101 determines an angle between the glass web 102 and the conveyance direction 107, as described above.
By sensing the angle between the glass web and the conveyance direction with an angle measurement device, the angle measurement device is able to sense the angular alignment of the glass web with the web conveyance pathway. Steering the glass web so that the glass web is angularly aligned with the web conveyance pathway may reduce web breakage and generally improve the alignment of the web with respect to glass processing apparatuses, such as coaters, bead removal machines, and the like. The angle measurement device may detect an angle between the glass web and the conveyance direction, or an angle between a separated thickened edge bead and the glass web which may not be detected by an edge sensor alone. Because an edge sensor only detects the position of an edge of the glass web at a single point, an edge sensor may fail to detect angular misalignment between the glass web and glass processing machine.
It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.
This application claims the benefit of priority under 35 U.S.C. §120 of U.S. Application Ser. No. 62/004,446, filed on May 29, 2014, the content of which is relied upon and incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62004446 | May 2014 | US |
