Web tension adjusting device

Abstract

An apparatus for self-adjusting a plurality of web contact pads (20) positioned to uniformly adjust the tension of a sagging web. The apparatus comprises actuators (15) connected to a transverse series of web contact pads (20), wherein each actuator (15) is pneumatically controlled and self-adjustable to provide uniform tension across the width of the web.

Description

Technical Field

[0001] The present disclosure relates generally to apparatus for adjusting web tension and, more particularly, to apparatus for evenly distributing web tension at multiple locations across the web having varying degrees of sag. Background Art

[0002] Many products are manufactured in continuous web form to benefit from the processing efficiencies and capabilities achievable with such methods. Certain manufacturing processes (e.g., fluid bearing molds) rely on uniformly distributed tension in the web. Therefore, if a web has one or more sagging corridors—i.e., areas where one section of the web is longer than an adjacent section of the web—it can create an uneven tension distribution at those locations, which can then directly cause defects in the final product.

[0003] Apparatus for equalizing web tension is known in the art. For example, U.S. Patent No. 2,696,192 (Birchler et al.) discloses an apparatus for equalizing web tension that includes a plurality of adjustable springs and associated "shoes" that press against the web, and U.S. Publication No. 2004 / 0129818 (Sugawara et al.) describes a magnetic belt tension controller that includes a tension sensing and tension adjustment unit configured to contact the surface of the magnetic belt to facilitate adjustment of the thrust force. Summary of the Invention

[0004] The present disclosure relates to an apparatus for self-adjusting a plurality of actuators positioned to uniformly adjust the tension of a loose web. The apparatus comprises a transverse series of actuators, each of which is pneumatically controlled and self-adjusts to provide uniform tension across the width of the web.

[0005] The term "web" is used herein to describe a thin material that is manufactured and / or processed in the form of a continuous, flexible strip. A web may include, for example, plastic, paper, textile, metal, and composites of such materials.

[0006] A further understanding of the features and advantages of the present disclosure will be obtained upon consideration of the detailed description and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is an overall configuration diagram of a web handling system including the web tension adjustment apparatus of the present disclosure.

[0008] Figure 2 is a perspective view of an embodiment of a web tensioning apparatus of the present disclosure.

[0009] Figure 3 yes Figure 2Cross-sectional view of a web tensioning device.

[0010] Figure 4 yes Figure 3 Cross-sectional view of a portion of a piston assembly of a web tensioning apparatus.

[0011] Reference symbols used repeatedly in the specification and drawings are intended to represent the same or similar features or elements of the present disclosure. It should be understood that those skilled in the art can design many other modifications and embodiments that fall within the scope and spirit of the principles of the present disclosure. The accompanying drawings may not be drawn to scale. DETAILED DESCRIPTION

[0012] The present disclosure provides apparatus and methods for uniformly adjusting the tension of a web having varying degrees and locations of sag. Such uniform tension adjustment of the web can allow tension-dependent processes, such as web coating and lamination, to be performed with reduced waste and increased throughput, and using substrates that were previously not possible.

[0013] Figure 1 One embodiment of a web handling system 50 including the web tensioning apparatus 10 of the present disclosure is shown. The web handling system 50 can be suitable for use in a variety of web handling applications, such as, for example, general web transport, web lamination processes, and web coating processes involving both planar and non-planar webs. The web handling system contemplated by the present disclosure generally includes frame members 42, 43, 45 configured to support a plurality of rollers (also referred to herein as "idlers") 44; a tension measuring device 46; and the web tensioning apparatus 10. During the manufacturing process, a web 5 is advanced from a supply drum (not shown) around the rollers 44, which guide the web 5 over the web tensioning apparatus 10 and the tension measuring device 46 to a take-up drum (not shown).

[0014] The web tensioning apparatus 10 is typically comprised of an array of hollow ultra-high molecular weight polyethylene ("UHMWPE") components, referred to herein as "web contact pads," machined with a 3.5 inch radius on the side facing outward. In some preferred embodiments, the starting material for the web contact pads is UHMWPE sheet (obtained from General Polymeric Corporation, Reading, PA, under the trade designation "GENPORE" porous plastic sheet). The web contact pads are secured to an actuator (obtained from Airpot Corp., Norwalk, CT, USA, under the trade designation "AIRPEL" piston cylinder assembly model 2KS160-1.0CP) having a 7 / 16" diameter hole drilled through the center of the actuator head to provide an actuator assembly. Passing through the actuator opposite the sintered plastic component is a gas manifold. The manifold may have, for example, two connections, one for 1 / 4" NPT quick disconnect fittings, and the other is 3 1 / 4" NPT barded fittings so that it can be supplied by a blower or high pressure gas (e.g., air) line. This design allows gas to flow into the manifold, through the actuator, and through the sintered plastic web contact pad.

[0015] Figure 2 One embodiment of a web tensioning apparatus 10 according to the present disclosure is shown. Figure 2 , the web tensioning apparatus 10 includes a gas distribution manifold 11 having at least one of a first gas inlet 12 and a second gas inlet 13. In some embodiments, the first gas inlet 12 can operate at a lower gas pressure than the second gas inlet 13. Adjacent the gas distribution manifold 11 is a piston holder 14 configured to support a plurality of piston assemblies 15 (not shown; see Figure 3 and 4 The piston retainer 14 is adjacent to and attached to the proximal machining connector 16 and the distal edge guard 17. The proximal machining connector 16 is secured by a plurality of connectors 18 to a support plate 19 adjacent to a plurality of web contact pad assemblies, i.e., a combination of the piston assembly 15 and the web contact pad 20.

[0016] Figure 3 Shown Figure 2 A cross-sectional view of a web tension adjustment device 10 is shown. Figure 3, web contact pad 20 includes a top surface wall 20a, side walls 20b, and an inner surface wall 20c surrounding cavity 40. Typically, the thickness of side wall 20b is greater than the distance between top surface wall 20a and inner surface wall 20c. Vertical arrows indicate the direction of pressurized gas flow through first gas inlet 12 toward piston assembly 15 and into contact pad assembly 20. During operation, piston assembly 15 and its associated web contact pad 20 independently move up and down to accommodate changes in web tension as web 5 passes over top surface 20a of web contact pad 20, thereby uniformly adjusting the tension of webs having varying degrees and locations of sag.

[0017] Figure 4 Shown Figure 3 1 is a cross-sectional view of a portion of a piston assembly 15 of a web tensioning apparatus, detailing the arrangement of a washer 36, spacer 26, piston shaft 30, piston head 22, retaining ring 32, and optional cylinder wall 24.

[0018] Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

[0019] Example

[0020] Unless otherwise indicated or readily apparent from the context, all parts, percentages, ratios, etc. in the examples and the remainder of the specification are by weight.

[0021] Material

[0022]

[0023] Sample evaluation

[0024] A first evaluation was performed using a commercial tension equalizing device and a tension measuring device with the web 1 passing through the device in an orientation such that the web traveled approximately 80 degrees on a conventional web line idler, 30 degrees on the tension equalizing device, and then 80 degrees on the shaft tension measuring device. The web 1 was passed through the web line at 15 feet per minute (4.57 m / min) and 1 pli (pounds force per linear inch) (1.75 N / cm). The winding tension was measured and controlled by using two rolls equipped with load cells, applying brakes on the unwinding station of the roll of web 1, and using a clamping pull roll. The web 1 was pulled through the web line at 11.8 scfm (20.1 m / min) on one side. 3hr) and an open line at 100 psi (689 kPa) on the opposite side with unregulated flow. Web 1 shaft tension measurements were collected from the tension measurement device, with the numbers recorded using an OMEGA OM-DAQXL data logger. Two blanks were removed and replaced with OMEGA load cells so that one measured directly in the sag shaft and the other measured the force two units away from the sag shaft. These locations are represented by their cross-web orientation, such as T D@X” , and recorded in Table 1 as Comparative Example C1.

[0025] The second evaluation was performed using a commercial tension equalizing device and a tension measuring device with a web 1 passed through the orientation of the device, the orientation causing the web to travel approximately 80 degrees on a conventional web line idler, 30 degrees on the tension equalizing device, and then 80 degrees on the corridor tension measuring device. The web 1 passed through the web line at 15 feet per minute (4.57 m / min) and 1 pli (pounds of force per linear inch) (1.75 N / cm). Winding tension was measured and controlled by using two rollers equipped with load cells, applying brakes on the unwinding station of the roll of the web 1, and using a clamping traction roll. No air flow was supplied to the tension equalizing device. As the web 1 passed through the above configuration, corridor tension measurements were collected from the tension measuring device, with OMEGA OM-DAQXL data loggers recording the numbers. Two blank components were removed and replaced with OMEGA load cells so that one directly measured the sagging corridor, and the other measured the force of two units away from the sagging corridor. These locations are indicated by their cross-web direction, such as T D@X” , and recorded in Table 1 as Comparative Example C2.

[0026] A third evaluation was conducted using a comparison idler roller and a tension measuring device with the web 1 passing through the device in an orientation such that the web traveled approximately 90 degrees on a conventional web line idler and then 90 degrees on a tension measuring device. The configuration of the tension measuring device was the same as the first evaluation, but the tension equalizing device was removed and replaced with a web tension adjustment device of the present disclosure. The web 1 passed through the web line at 15 feet per minute (4.57 m / min) and 1 pli (pounds-force per linear inch) (1.75 N / cm). The winding tension was measured and controlled by using two rollers equipped with load cells, applying brakes on the unwinding station of the roll of web 1, and using a clamping traction roll. As the web 1 passed through the above configuration, the tunnel tension measurements were collected from the tension measuring device, with the numbers being recorded using an OMEGA OM-DAQXL data logger. Two blank components were removed and replaced with OMEGA load cells so that one measured the sag tunnel directly and the other measured the force of two units away from the sag tunnel. These locations are indicated by their cross-web direction, such as T D@X”, and recorded as Example 1 in Table 1.

[0027] Table 1. Web evaluation results

[0028] Cross-web position Comparative Example C1* Comparative Example C2* Example 1* <![CDATA[T D@1.25” ]]> 1-1.1 0.6-0.7 0.5 <![CDATA[T D@4.25” Location of Songchui Corridor]]> 0.6-0.8 0.3-0.4 0.5

[0029] *Units are in pounds-force.

Claims

1. A web tensioning apparatus comprising a first gas inlet, a plurality of piston assemblies, each piston assembly connected to a web contact pad comprising a sintered plastic material to provide a web contact pad assembly, wherein each web contact pad assembly is independently pneumatically controlled and self-adjusts to provide uniform tension across the width of the web.

2. The web tensioning apparatus of claim 1, wherein the piston assembly comprises a cylinder wall.

3. A web tensioning apparatus according to claim 1 or claim 2, wherein the sintered plastic material comprises ultra high molecular weight polyethylene.

4. The web tensioning apparatus according to any one of claims 1 to 3, comprising 2 to 100 web contact pad assemblies, optionally 3 to 75 web contact pad assemblies, optionally 4 to 50 web contact pad assemblies.

5. The web tensioning apparatus according to any one of claims 1 to 4, further comprising a second gas inlet, wherein the first gas inlet operates at a lower gas pressure than the second gas inlet.

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