WO2020069388A1 - Single-sided ultrasonic welding mechanism and related techniques - Google Patents

Abstract

A system for constructing assembled polymeric fill or pack products that allows fluid flow therethrough includes a first sheet, a second sheet and an ultrasonic welding horn. The first and second sheets have first and second projections extending therefrom at first and second projection angles, respectively. The first projection angle is substantially equal to the second projection angle. The second projection is nestable within the first projection in a nested configuration. The ultrasonic welding horn connected to a tip that has a depression at a distal end with a butt end spaced from the distal end. The depression has sides extending at a tip angle relative to a longitudinal axis of the horn. The depression is configured to mate with the first projection to ultrasonically weld the nested first and second projections and connect the first sheet to the second sheet.

Description

Single-Sided Ultrasonic Welding Mechanism and Related Techniques

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of ET.S. Provisional Patent Application No. 62/738,585, filed September 28, 2018 and titled“Single-Sided ETltrasonic Welding Mechanism and Related Techniques” the entire contents of which are incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] Contact bodies and cooling tower fill assemblies are constructed of a series of sheets that are connected together to provide structural integrity and engagement. The sheets are typically mechanically or adhesively bonded together to form packs, fill or assemblies. US Patent Nos.

6,544,628 (‘“628 patent”), titled“Method of Making Contact Bodies;” 6,640,427, titled“Apparatus for Making Contact Bodies” and 6,877,205, titled“Method of Making Contact Bodies” disclose mechanisms and methods for mechanically connecting sheets or mechanical assembly (“MA”) of sheets to construct contact bodies or packs. The described MA technique involves assembly of contact bodies and also describes the method and equipment utilized to assemble the packs. The pair/pack assembly technique and method adequately assembles fill products and is used extensively by manufacturers internationally both in factories and in the field to assemble fill products. Louver and drift products, however, are generally not constructed using this pair pack assembly method as the sheets in the louver and drift products are typically assembled with edge bonding only, although they are not so limited.

[0003] The pair/pack MA technique enables the assembly of fill packs from thermoformed sheets through a multi-stage manufacturing and assembly process. A portion of the assembly process includes arranging individual sheets into pairs connecting all interior and edge connections formed into the sheets. A subsequent stage is the assembly of these fully assembled pairs into packs by edge bonding a first bonded pair to a second bonded pair, but the interior projection pairs are typically not connected because there is no access to both sides of the interior pairs for MA and prior art bonding techniques require access to both sides of the assembled pairs. Successive stacking and connection of more than three thermoformed sheets with the interior projection pairs connected into a fill pack is generally not feasible due to a lack of access to the underside of the third or top thermoformed sheet on the assembly at the internal connection locations. The structural performance of the resulting MA pair/pack product, although functional, is reduced over a fully assembled pack with each of the projection pairs, including all of the interior pairs, connected. The compressive strength of the MA pack in an unrestrained system is limited by the failure mechanism of the pairs, as assembled pairs buckle like a column due to lack of internal stabilization at the mid- height of the assembled pairs. The lack of access to the underside of the thermoformed sheet at internal connection locations after at least three sheets are stacked is also a limitation for other methods of assembly such as thermal and ultrasonic welding with an anvil.

[0004] Typically, ultrasonic welding requires stabilization of a bottom surface of the material being ultrasonically welded to provide sufficient internal friction to develop and raise the

temperature of the material at the interface of the surfaces to be welded. Ultrasonic welding is an industrial technique whereby high-frequency ultrasonic acoustic vibrations are locally applied to workpieces being held together under pressure to create a solid-state weld. Ultrasonic welding is commonly used for plastics, and especially for joining dissimilar materials. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together, as the materials themselves are vibrated and urged together to form a fastening joint or connection. Both thermal welding and ultrasonic welding typically require pressure to comingle the molecular chains at the interface of the plastic parts that are being joined to achieve sufficient weld strength for structural performance. Two-sided access to inner connections of sheet pairs is generally not available for both two-sided welding techniques and MA, so the two-sided welding and MA processes are impractical for full assembly of packs. It would, therefore, be desirable to design, develop and deploy a system and technique for ultrasonically welding thermoformed sheets from one side of the sheets that make up fill packs. The shortcomings and disadvantages of the prior art techniques and mechanisms are addressed by the preferred system and method of the present invention.

BRIEF SUMMARY OF THE INVENTION

[0005] Briefly stated, the preferred invention is directed to a system for constructing assembled polymeric fill or pack products that allows fluid flow therethrough. The system includes a first sheet, a second sheet and an ultrasonic welding tip. The first and second sheets have first and second projections extending therefrom at first and second projection angles, respectively. The first projection angle is substantially equal to the second projection angle. The second projection is nestable within the first projection in a nested configuration. The ultrasonic welding tip has a depression at a distal end with a butt end spaced from the distal end. The depression has sides extending at a tip angle relative to a longitudinal axis of the tip. The depression is configured to mate with the first projection to ultrasonically weld the nested first and second projections and connect the first sheet to the second sheet.

[0006] In another aspect, the preferred invention is directed to an ultrasonic welding system for connecting first and second sheets having first and second frusta-conical projections. The ultrasonic welding system includes a power supply, a converter in communication with the power supply, a booster in communication with the converter, a controller in communication with the power supply, a horn connected to the booster and a tip connected to the horn. The horn may include an integrally formed tip with a depression extending along a longitudinal axis from a distal end of the horn to a butt end or may be connected to the tip, which is removably attached to the horn, with a depression extending along a longitudinal axis from the distal end of the tip. The controller is configured to introduce an ultrasonic vibration into the horn and subsequently into the tip. The depression on the horn or the tip is configured to engage the first projection when the first and second projections are in a nested configuration to form an ultrasonic weld between the first and second projections to connect the first and second sheets.

[0007] In a further aspect, the preferred invention is directed to an ultrasonic welding system for connecting first and second sheets having first and second edges. The ultrasonic welding system includes a power supply, a converter in communication with the power supply, a booster in communication with the converter, a controller in communication with the power supply, the converter and the booster, and a horn connected to the booster. The horn may include a V-shaped groove extending along a longitudinal axis from a distal end of the horn to a butt end or may be connected to a removable tip with the V-shaped groove extending along a longitudinal axis from the distal end of the tip to the butt end. The controller is configured to introduce an ultrasonic vibration into the horn or into the horn and then into the tip. The groove is configured to engage the first and second edges to form an ultrasonic weld between the first and second edges to connect the first and second sheets.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0008] The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: [0009] Fig. l is a cross-sectional view of an ultrasonic welding tip in accordance with a first preferred embodiment of the present invention, wherein the ultrasonic welding tip is positioned on a first projection and a second projection in a nested configuration;

[0010] Fig. 1 A is a cross-sectional view of an ultrasonic welding tip of Fig. 1, wherein the tip is positioned for welding first and second projections in the nested configuration;

[0011] Fig. 1B is a cross-sectional view of a nested pair or nested first and second projections ultrasonically welded utilizing the ultrasonic welding tip of Fig. 1;

[0012] Fig. 2 is a cross-sectional view of an ultrasonic welding tip in accordance with a second preferred embodiment of the present invention, wherein the ultrasonic welding tip is positioned over first and second projections of first and second contact sheet in a nested configuration;

[0013] Fig. 2A is a cross-sectional view of a nested pair or paired first and second projections ultrasonically welded utilizing the ultrasonic welding tip of Fig. 2;

[0014] Fig. 3 is a cross-sectional view of an ultrasonic welding tip in accordance with a third preferred embodiment of the present invention, wherein the ultrasonic welding tip is positioned over first and second projections of first and second contact sheet in a nested configuration;

[0015] Fig. 3 A is a cross-sectional view of a nested pair or paired first and second projections ultrasonically welded utilizing the ultrasonic welding tip of Fig. 3;

[0016] Fig. 4 is a side elevational view of an ultrasonic welding tip in accordance with a fourth preferred embodiment of the present invention;

[0017] Fig. 4A is a cross-sectional view of an edge of a pair of sheets or first and second sheets connected using the ultrasonic welding tip of Fig. 4;

[0018] Fig. 5 is a side elevational view of an ultrasonic welding tip in accordance with a fifth preferred embodiment of the present invention, wherein the ultrasonic welding tip is positioned on an alignment feature of a sheet to be welded; and

[0019] Fig. 5 A is a bottom plan view of the ultrasonic welding tip of Fig. 5.

DETAILED DESCRIPTION OF THE INVENTION

[0020] Certain terminology is used in the following description for convenience only and is not limiting. ETnless specifically set forth herein, the terms“a”,“an” and“the” are not limited to one element but instead should be read as meaning“at least one”. The words“right,”“left,”“lower,” and“upper” designate directions in the drawings to which reference is made. The words“inwardly” or“distally” and“outwardly” or“proximally” refer to directions toward and away from, respectively, the geometric center or orientation of the ultrasonic welding components and instruments and related parts thereof. The terminology includes the above-listed words, derivatives thereof and words of similar import.

[0021] It should also be understood that the terms“about,”“approximately,”“generally,” “substantially” and like terms, used herein when referring to a dimension or characteristic of a component of the invention, indicate that the described dimension/characteristic is not a strict boundary or parameter and does not exclude minor variations therefrom that are functionally the same or similar, as would be understood by one having ordinary skill in the art. At a minimum, such references that include a numerical parameter would include variations that, using

mathematical and industrial principles accepted in the art (e.g., rounding, measurement or other systematic errors, manufacturing tolerances, etc.), would not vary the least significant digit.

[0022] Ultrasonic welding systems typically include a press, usually with a pneumatic or electric drive, to assemble two parts under pressure between the press and a backstop, nest, anvil or fixture. In operation, parts or a joint that will be connected with ultrasonic welding are placed between the press and the backstop. The press is urged toward the backstop to apply pressure or compressive forces to the parts or joint and ultrasonic vibrations are applied to the press and, thereby, the parts or joint. The pressure and vibrations drive pressurized high frequency vibration into the interfaces, thereby melting or joining the parts or joint together. The ultrasonic welding system may include an ultrasonic stack that includes a converter or piezoelectric transducer, an optional booster and a Sonotrode or horn. The ultrasonic welding system may alternatively also include a tip that is connected to the horn with a feature that facilitates welding the particular component that is contacted by the horn or the tip. All three elements of the ultrasonic welding stack are specifically tuned to resonate at the same ultrasonic frequency, typically fifteen, twenty, thirty, thirty-five or forty kilohertz (15, 20, 30, 35 or 40 kHz), although the stack is not so limited and may be otherwise designed and configured to operate at different frequencies, depending on the material being welded, the environment and related design considerations. The converter preferably converts an electrical signal into a mechanical vibration using the piezoelectric effect. The booster preferably modifies the amplitude of the vibration mechanically. The booster is also used in standard systems to clamp the stack in the press. The horn or Sonotrode preferably takes the shape of the part being welded, modifies the amplitude of the vibration, and mechanically applies the mechanical vibration to the parts or joint that is being welded. Alternatively, the horn or Sonotrode may include a separate tip that takes the shape of the part being welded, modifies the amplitude of the vibration, and mechanically applies the mechanical vibration through the tip to the parts or joint that is being welded. An electronic ultrasonic generator or power supply generates a high power electric signal with a frequency that matches the resonance frequency of the stack. A controller controls the movement of the press and delivery of the ultrasonic energy to the parts or joint that is being welded or joined. Utilization of automation with ultrasonic welding to construct the preferred fill assembly provides a cost advantage where the costs for materials (solvents and resin), assembly labor, and maintaining permits for volatile organic compounds (VOC) emissions are realized.

[0023] Referring to Figs. 1-3, preferred embodiments of the present invention are directed to a single-sided ultrasonic welding mechanism, generally designated 10, for ultrasonically welding relatively thin polymeric sheets 12, 12 A, 12B to each other. The preferred single-sided ultrasonic welding mechanism 10 is configured for ultrasonically welding connection projections 14, 14A, 14B that extend from the sheets 12, 12 A, 12B and are nestable within each other across assembled or adjacent sheets 12, 12A, 12B. The first preferred single-sided ultrasonic welding mechanism 10 includes a controller 16, a power supply 18, a converter 20, a booster 22 a horn or Sonotrode 23 and a tip 24, each of which may be utilized and employed with all of the preferred embodiments of the present invention. The controller 16 is preferably in communication with the power supply 18 and other related components of the system, such as mechanisms to assemble the adjacent sheets 12,

12A, 12B and move the assembled and joined sheets 12, 12A, 12B, to control operation of these components of the preferred invention and may also be in communication with additional components of the system, such as machinery (not shown) that automate stacking and engagement of multiple sheets 12, 12A, 12B to form and assemble fill assemblies or packs (not shown), which are generally described in the‘628 patent.

[0024] The single-sided ultrasonic welding mechanism 10 is not limited to inclusion of each of the controller 16, converter 20, tip 24 and booster 22 and may be designed and configured with various combinations of these components without significantly impacting the basic operation of the welding mechanism 10. In a preferred example, the single-sided ultrasonic welding mechanism 10 may be comprised of a handheld ultrasonic welder with at least the power supply 18 and the horn 23 that is designed to ultrasonically weld nested projections 14, 14A, 14B of assembled sheets 12, 12A, 12B. For example, first and second projections 14 A, 14B of the first and second sheets 12 A, 12B may be nested within each other and ultrasonically welded via approach and operation from a single side of the projections 14A, 14B with the preferred welding mechanism 10. In such a preferred operation, the first or top projection 14A of the nested projections 14, 14A, 14B is directly contacted by a depression or hollow shape 25 that may be formed on the horn 23, but is formed on the tip 24 in the first preferred embodiment, to ultrasonically excite and weld the projections 14, 14 A, 14B. The welding mechanism 10 may utilize the horn 23 or the tip 24 that has a relatively flat or planar distal end (not shown) that contacts the nested projections 14, 14 A, 14B to ultrasonically weld top surfaces or top walls l4a of the nested projections 14, 14A, 14B or areas around a base of the nested projections 14, 14 A, 14B to secure the adjacent sheets 12, 12 A, 12B together. The preferred welding system may also be configured to create welds in the nested projections 14, 14A, 14B at top and/or sidewalls and in the sheets 12, 12A, 12B adjacent the bases of the projections 14, 14A, 14B.

[0025] The preferred single-sided ultrasonic welding mechanism 10 may also be adapted for connecting sheets 12 at locations on the sheets 12 adjacent alignment features or ultrasonic welding and alignment features that are formed into the sheets 12. These features may include thickened portions on the sheets 12 that are in facing engagement in an assembled configuration, alignment pins or other features where the sheets 12 may be ultrasonically welded together. Certain flat locations of the sheets 12 may be joined or connected by adhesive bonding or gluing in prior art operations. Although these glue connection positions generally have aligning features along the bond site, they are flat and in the plane of the successive sheets 12 of the pack assembly. The valley of the top or first sheet 12A is preferably bonded with or to the peak of the bottom or second sheet 12B in a preferred connecting technique. The preferred sheets 12 with the projections 14 may be welded with the flat tip or flat section welding tip (not shown) by placing the flat portion (not shown) of the horn 23 or the flat portion (not shown) of the tip 24 in contact with a top surface l4a of the projection 14 without an anvil or backstop positioned behind the top surface l4a or within the projection 14. The resulting weld of the top surfaces or top walls l4a of the nested first and second projections 14 A, 14B may translate at least partially into a sidewall l4b of the first and second projections 14A, 14B when force is applied and the nested projections 14A, 14B are heated by the ultrasonic resonance applied by the flat section (not shown) of the horn 23 or the tip 24. The sidewall l4b is generally welded adjacent the top surface or top walls l4a of the projections 14A, 14B. The nested projections 14A, 14B may subsequently have a reduction in height as the sidewalls l4b of the projections 14 A, 14B deform under the relatively low force applied to the projections 14, 14 A, 14B and the fill sheets 12, 12 A, 12B. The ability to weld the nested projections 14, 14 A, 14B without an anvil or other backstop at an opposing side of the projections 14, 14 A, 14B relative to the ultrasonic welder, horn 23 or tip 24 was unexpected as previous trials and tests without the backstop or anvil were generally unacceptable. In addition, those having ordinary skill in the art advised an anvil or backstop would be required for ultrasonic welding of two nested projections 14, 14 A, 14B. The projections 14 are described herein and identified generically with the reference numeral“14” and the first and second projections are generally identified by reference numerals“14A” and “14B,” herein, although the projections 14, 14 A, 14B are preferably only limited as being designed and configured for nesting or engaging to align and the sheets 12, 12 A, 12B and to provide a location for ultrasonically welding the sheets 12, 12 A, 12B together to connect the adjacent sheets 12, 12A, 12B for assembly into packs. The specific frusta-cone shape of the projections 14, 14A, 14B shown in Figs. 1-3A is not limiting and the projections 14, 14A, 14B may be otherwise designed and configured for aligning the adjacent sheets 12, 12A, 12B and providing a location for ultrasonically welding the sheets 12, 12A, 12B together to assemble the fill packs. As a non limiting example, the projections 14, 14 A, 14B may be configured as mating sheet stabilization features and the ultrasonic horn 23 or the tip 24 may be designed and configured for welding the sheets 12, 12 A, 12B together around or near these stabilization features.

[0026] The first preferred single-sided ultrasonic welding mechanism 10 includes the ultrasonic horn 23 with a tip 24 removably connected thereto. The tip 24 includes the depression or hollow shape 25 at a distal end that has a similar or substantially the same shape of the projection 14 that captures and engages the sidewall l4b of the top projection 14 or the top comer of nested first and second projections 14 A, 14B in an assembled configuration during an ultrasonic welding operation. The horn 23 may alternatively be integrally formed with the depression 25 thereon (not shown), although the removable tip 24 is preferred to provide flexibility during operation of the welding mechanism 10 by switching from various tips 24 having different depressions 25 or configurations for welding or joining different features on the sheets 12, 12A, 12B or the projections 14, 14A, 14B. The ultrasonic hom 23 may be comprised of a component with a handle for grasping by an operator, a stem for engagement with an automated operating mechanism or may include the removable tip 24 that is engaged with a handle or stem for manipulating the horn 23. The tip 24 and horn 23 are shown in the first preferred embodiment as separate components with the tip 24 being removably mountable to the horn 23 with a threaded stem 24a, but may be configured such that the hom 23 includes the depression 25 or other feature integrally formed thereon for directly contacting the sheets 12, 12A, 12B and/or the projections 14, 14A, 14B for ultrasonically welding the parts together. The preferred tip 24 includes the threaded stem 24a at a proximal end that is mountable to the horn 23. This first preferred tip 24 is able to connect or bond the nested projections 14, 14A,

14B to each other, although under certain conditions and configurations, the first preferred tip 24 also contacts and connects the sheet 12 near the base of the projection 14 at the flat portion of the sheet 12. The primary advantage of the first preferred tip 24 is that the tip 24 generally does not slip from the top of the projection 14 and is retained in contact with the projection 14, particularly the sidewall l4b, throughout the welding cycle. [0027] In the first preferred embodiment, the tip 24 is constructed with a tip angle Q comprised of the angle of sides 25a of the depression 25 relative to a longitudinal axis 26 of the tip 24. In the first preferred embodiment, the tip angle Q is greater than a projection angle D, which is comprised of the angle of sidewalls l4b of the projection 14 relative to the longitudinal axis 26. In this first preferred embodiment, the depression 25 has a smaller tip width WH measured at a butt end 25b of the depression 25 relative to a projection width WP at the top surface l4a of the top wall of the projection 14, 14A, 14B. This configuration of the first preferred depression 25 results in the sides 25a of the depression 25 initially contacting the nested projections 14, 14A, 14B at the intersection of the top surface l4a and the sidewall l4b. The first preferred tip 24, therefore, contacts the upper projection 14 at the top edge and progressively welds from the top edge downward along the sidewall l4b, as the material of the nested projections 14, 14 A, 14B such as the first and second projections 14A, 14B of Fig. 1A, deform when heated by the ultrasonic resonance. The pressure from the first preferred tip 24 is applied first to the top edge of the first or top projection 14A as sides 25a of the tip 24 contact the projection 14A, then progresses toward the base of the nested projections 14A, 14B as the top portion of the sidewalls l4b of the nested projections 14, 14A, 14B deform to conform or deform in the shape of the depression 25. In the first preferred embodiment, the sidewall l4b of the projection 14 extends at the projection angle D relative to a longitudinal axis 26 of the projection 14 of approximately fifteen degrees (15°) and the tip 24 is configured with its sides 25a extending at the tip angle Q of approximately eighteen degrees (18°) relative to the longitudinal axis 26. This first preferred embodiment of the tip 24 and projections 14, 14A, 14B results in a weld at the top edge of the nested projections 14, 14 A, 14B that extends down the sidewalls l4b, but preferably ends short of the base of the sidewalls 14 or short of the flat portions of the sheets 12, 12A, l2b at the base of the sidewalls 14. The first preferred tip 24 provides a relatively consistent weld to connect the nested projections 14, 14 A, 14B and the sheets 12, 12 A, 12B. The positioning near the top surface l4a of the projections 14, 14 A, 14B results in the connection allowing movement between the assembled sheets 12, 12 A, 12B, thereby increasing the deflection of the assembled pack during structural testing. The first preferred depression 25 of the tip 24 is shown in Figs. 1 and 1 A, although the depression 25 is not limited to being formed on the separate, removable tip 24 and may be integrally formed on the horn 23.

[0028] When an assembled pack (not shown) with nested projections 14, 14A, 14B is ultrasonically welded using the first preferred tip 24, the overall compressive deflection of the assembled pack is higher than a mechanically assembled pack, such as a pack connected mechanically in accordance with the teachings described in the‘628 patent. The overall compressive test approximates performance of the fill pack in an installed configuration within a cooling tower or other application. The higher deflection is due to an offset of an ultrasonic weld 15 formed at the sides of the nested projections 14, 14 A, 14B using the first preferred tip 24, relative to a sheet plane 28 defined by flat sections of the first and second sheets 12 A, 12B at the bases of the welded projections 14A, 14B. The first ultrasonic weld 15 formed by the first preferred tip 24 is spaced from the sheet plane 28 along the sidewalls of the projections 14A, 14B, thereby resulting in movement of the sheets 12, 12A, 12B relative to the plurality of ultrasonic welds 15 in the pack and the ability of the ultrasonic welds 15 to move based on a first moment arm M between the ultrasonic weld 15 and the sheet plane 28. The first preferred tip 24 may also include several different horn angles Q such that the ultrasonic weld 15 is positioned near the bottom of the sidewalls l4b nearer to the sheet plane 28. The first preferred tip 24 could also cause“oil canning” where the ultrasonic weld 15, in certain configurations, separates and“pops off’ the at least portions of the top wall or top surface l4a from the sidewalls l4b. The first preferred tip 24, however, typically results in structural ultrasonic welds 15 that connect the sheets 12, 12A, 12B, which may be formed more quickly and efficiently than the mechanical connections described in the‘628 patent.

[0029] Referring to Figs. 2 and 2A, in a second preferred embodiment, the tip 24' and projections 14', 14 A', 14B' are constructed and configured similar to the first preferred tip 24 and projections 14, 14A, 14B and the same reference numerals are utilized to identify the similar or the same features, with a prime symbol (') utilized to distinguish the features of the second preferred embodiment from the first preferred emboidment. In the second preferred embodiment, the tip angle q' and the projection angle D' are constructured to be substantially the same, such that the sides 25a' contact and come into facing engagement with the sidewall l4b' of the first or top projection 14A' in the nested configuration and during ultrasonic welding so that the sidewalls l4b' of the first and second projections 14 A', 14B' are welded and urged downwardly toward the sheet plane 28' in a welded configuration (Fig. 2A). In the second preferred embodiment, relief is provided at the butt end 25b' of the depression 25' such that the projection width Wp' is less than the tip width WH' such that the tops of the projections 14 A', 14B' are not significantly impacted by the second weld 15' or there is limited impact on the top walls or surfaces of the projections 14 A', 14B' by the weld 15'. The second weld 15' of the second preferred embodiment is spaced from the sheet plane 28' by a second moment arm M' that is typically smaller than the first moment arm M of the first preferred embodiment, but is spaced from the sheet plane 28', thereby resulting in deflection of the pack (not shown) assembled utilizing the tip 24' of the second preferred embodiment. Similar to the first preferred embodiment, the depression 25' of the second preferred embodiment may be integrally formed (not shown) in the horn 23 and the removable tip 24' may be eliminated from the assembly of the ultrasonic welding assembly 10'. The second preferred embodiment utilizes substantially the same controller 16, power supply 18, converter 20, booster 22 and horn 23 of the first preferred embodiment.

[0030] Referring to Figs. 1-3, it was desirable for certain applications and configuration to move the ultrasonic weld 15, 15' further downwardly toward the sheet plane 28, 28' in the connection between the nested projections 14 A, 14B, 14 A', 14B' to limit the above-described movements or deflections resulting from the first and second moment arms M, M'. In a third preferred

embodiment, a removable tip 54 having a depression 55 and sides 55a is constructed to operate similarly to the tips 24, 24' of the first and second preferred embodiments and may similarly, alternatively include the depression 55 formed in the horn 23. The depression 55 of the third preferred tip 54 includes a substantially frusta-conical upper section 56 and a fillet section 58 near a distal end of the tip 54. The third preferred tip 54 includes a threaded stem 54A at a proximal end that is mountable to the horn 23 and booster 22 and may alternatively be integrally formed with a handle or stem as part of the horn 23. The fillet section 58 arcs outwardly from the upper section 56 near the distal end of the tip 54 and is sized and configured to contact the sidewall l4b of the projection 14 or the sidewall l4b of the first projection 14A in a nested configuration first above, but near the intersection of the sidewall l4b and the flat portion of the sheet 12 or the first sheet 12A to prevent cutting through the sheets 12, 12A and the sidewall l4b with a sharp edge on the tip 54. Additionally, the tip 54 of the third preferred embodiment is designed, sized and configured with a cavity 60 defined between the top surface l4a of the projection 14 and a butt end 55b of the depression 55 in the tip 54. The cavity 60 reduces the potential for oil canning or tearing of the ultrasonic weld near the intersection with the sheets 12A, 12B during the ultrasonic welding process. The non-contact facilitated by the cavity 60 adjacent the top wall l4a of the projection 14 generally prevents the top surface l4a of the projection 14 or the ultrasonic weld 15" (Fig. 3 A) from being separated from the sheets 12 A, 12B or from holes being created in the material of the projection 14 during the welding process. The tip angle 5Q and the projection angle 5D of the third preferred embodiment are substantially the same as described above with respect to the first preferred embodiment, but are not so limited and may be otherwise designed and configured, based on designer preferences and other related considerations that would be apparent to one having ordinary skill in the art based on a review of the present disclosure.

[0031] The tip 54 of the third preferred embodiment positions the third or final weld 15" closer to the sheet plane 28 in the assembled configuration compared to the first and second preferred tips 24, 24'. Depending on where the third preferred tip 54 contacts the sidewalls l4b of the projections 14, the force applied by the tip 54 on the projections 14 and other factors, the top surface l4a and the resulting weld 15" may be spaced at different distances from the sheet plane 28, although the third preferred tip 54 reduces the height of the projections 14, 14 A, 14B after welding. In the third preferred embodiment, the reduction in height of the projections 14, 14A, 14B is approximately fifty percent (50%). The third weld 15" resulting from the third preferred tip 54 is, therefore, closer to the sheet plane 28 than the first and second ultrasonic welds 15, 15' resulting from the first and second preferred tips 24, 24'. A spacing or third moment arm M" resulting from the third preferred tip 54 is generally smaller than the first and second moment arms M, M' resulting from the first and second preferred tips 24, 24'. The third preferred weld 15", thereby, typically defines a lower profile such that airflow through the assembled fill is augmented and pressure drop is reduced. The third preferred tip 54 contacts the sidewall l4b of the projection 14, 14 A, 14B and reduces the height of the nested projections 14, 14 A, 14B during the welding process approximately to the midpoint or such that the top surface or top wall l4a is approximately half the height of the non-welded projections 14, 14A, 14B. The resulting third weld 15" is, accordingly, close to the sheet plane 28 or bottom of the projection 14 in the assembled and welded configurations, thereby resulting in a larger cross-sectional area of the welded surfaces and reduced or smaller third moment arm M". The cavity 60 between the top surface l4a and the butt end 55b of the depression 55 remains and becomes continuous with the convex sidewall surface to maintain the ability to eliminate oil canning. An artifact of the design and method during welding utilizing the third preferred tip 54 is that a height of the projection 14 after the ultrasonic welding process is reduced during a short weld time (for example, approximately four tenths of a second (0.4 sec) when welding polyvinyl chloride (PVC) material), which also minimizes the air side pressure drop for the application of the sheets 12, 12A, 12B when assembled into packs, because the height of the projection 14 is significantly reduced toward the sheet plane 28 and material of the projection 14 does not extend significantly above the surface of the first sheet 14A to interrupt airflow through the packs.

[0032] Connecting the nested projections 14, 14 A, 14B, 14 A', 14B' utilizing the preferred tips 24, 24', 54 is advantageous for several reasons, including the ability to connect adjacent sheets 12, 12A, 12B, 12A', 12B' from a single side, as only single side access is available after two sheets 12, 12A, 12B, 12A', 12B' are connected and typical assemblies of fill or pack assemblies include at least three (3) and often many more sheets 12, 12 A, 12B, 12 A', 12B' in an assembly or fill pack. The single-sided ultrasonic welding connections of the therm oformed fill sheets 12, 12 A, 12B, 12 A',

12B' stabilize the location of the therm oformed fill sheets 12, 12 A, 12B, 12 A', 12B' relative to each other and produce a fill or pack assembly with significant strength and stability. This preferred design of the sheets 12, 12A, 12B, 12A', 12B', including the nestable projections 14, 14A, 14B,

14 A', 14B', enables the ultrasonic welding equipment to apply force from the sidewalls l4b, l4b' to achieve the weld 15, 15', 15" without the need of an anvil positioned proximate to the bottom of the nested projections 14, 14A, 14B, 14 A', 14B' that are opposite the tips 24, 24', 54 during welding.

The nestable projections 14, 14A, 14B, 14A', 14B' in the sheets 12, 12A, 12B, 12 A', 12B' are preferred features for connecting the sheets 12, 12A, 12B, 12 A', 12B' utilizing the preferred welding tips 24, 24', 54, but are not so limited. The sheets 12, 12 A, 12B, 12 A', 12B' may include nearly any structure that can be welded without an anvil or welded from a single side by the preferred tips 24, 24', 54 or an alternative horn 23 with an integrally formed depression or cavity 25, 25', 60 that interacts with the feature to form a low-profile ultrasonic weld to connect the sheets 12, 12 A, 12B,

12 A', 12B'. An additional benefit to using the nestable projections 14, 14A, 14B, 14 A', 14B' with the sheets 12, 12A, 12B, 12 A', 12B' for ultrasonic welding is that the force applied to the nested projections 14, 14A, 14B, 14 A', 14B' is increased by the slope of the sidewalls l4b, l4b' of the projections 14, 14A, 14B, 14 A', 14B' and sides 25a, 25a', 55a of the depression 25, 25', 55. The deformation of the sidewalls l4b, l4b' at the contact point or area with the depression 25, 25', 55 increases the force applied to the connection during welding. In addition, use of the nestable projection 14, 14A, 14B, 14A', 14B' enables the sheets 12, 12A, 12B, 12 A', 12B' of the fill or pack to be assembled by either MA to crush the nested projections 14, 14A, 14B, 14 A', 14B', as is described in the‘628 patent, or utilizing the herein described ultrasonic welding techniques based on the needs of the customer. Accordingly, additional inventory of alternatively configured sheets 12, 12A, 12B, 12 A', 12B' is typically not required for multiple parts. The same sheets 12, 12A, 12B,

12 A', 12B' with the preferred nestable projections 14, 14A, 14B, 14 A', 14B' may also be adhesively bonded to connect or engage the sheets 12, 12A, 12B, 12 A', 12B' into assembled fill or packs. The preferred ultrasonic welding mechanism 10 is also able to achieve a relatively strong connection at the welds 15, 15', 15" from one side of the sheets 12, 12A, 12B, 12 A', 12B' by contacting the cone and energizing the ultrasonic welder, wherein the MA of the nestable projections 14, 14 A, 14B,

14 A', 14B' typically requires two-sided access to create the mechanical connection or crushing of the nestable projections 14, 14A, 14B, 14A', 14B'.

[0033] The preferred single-sided ultrasonic welding mechanism 10 with the preferred tips 24, 24', 54 and method can be modified to modify the resulting weld 15, 15', 15" by changing the weld duration of the tip 24, 24', 54, pressure applied by the tip 24, 24', 54 to the nested projections 14, 14A, 14B, 14 A', 14B' and additional components and steps. As a non-limiting example, the top surface l4a, l4a' of the nested projections 14, 14A, 14B, 14 A', 14B' may be welded by applying a tip or horn (not shown) with a flat bottom or distal surface to the top surface l4a, l4a' of nested projections 14, 14A, 14B, 14 A', 14B' to weld the top flat surfaces l4a, l4a' together, generally without directly contacting the sidewalls l4b, l4b'. This top surface weld adequately welds or connects the projections 14, 14A, 14B, 14 A', 14B' together, but limits the cross section of material or size of the weld (not shown) which directly impacts the strength of the assembled sheets 12, 12 A, 12B, 12 A', 12B' and the resulting fill or packs. Connecting the sheets 12, 12A, 12B, 12 A', 12B' utilizing this flat bottomed tip or horn and method also allows for more deflection in the assembled product, fill or pack, thereby producing a“spongy” product or a less-stiff product with a lower composite modulus (i.e., strength testing). The larger the bonded surface or weld 15, 15', 15" between the joined or connected projections 14, 14 A, 14B, 14 A', 14B' in the final fill or pack, generally the stronger the weld 15, 15', 15" or ultimate strength of the connection. The closer the weld 15, 15', 15" is positioned relative to the sheet plane 28, 28', generally the less movement in the connection between successive sheets 12, 12 A, 12B, 12 A', 12B' thereby lending itself to a higher modulus or stiffness.

[0034] In another preferred example, the single-sided ultrasonic welding mechanism 10 may be designed and configured to weld the sidewalls l4b, l4b' of the projections 14, 14A, 14B, 14 A', 14B'. Welding the sidewalls l4b, l4b', such as with the tip 24' of the second preferred embodiment, provides more weld contact area and may increase the weld strength while reducing the movement at the connection by reducing the second moment arm M'. In the second preferred embodiment the tip 24' is designed for a close tolerance between the projection angle D' and the tip angle q', wherein the projection and tip angles D', q' are substantially the same. Since the projection angle D' of the sidewalls l4b' of the projections 14', 14 A', 14B' are configured at an approximate ten to fifteen degree (10-15°) angle, the second preferred tip 24' that contacts the sidewall l4b' of the projection 14, 14 A' without contacting the top surface l4a' is designed and configured to self-align with the sidewall l4b' and provide increased pressure of the contact surface between the sides 25a' of the depression 25' and the sidewall l4b' of the projections 14, 14A' for the same applied vertical force over a vertical motion resulting in a substantially horizontal weld interface.

[0035] In an alternative preferred method, the horn or tip and projections may be designed and configured such that the single-sided ultrasonic weld results in welding both the top surfaces l4a and sidewalls l4b of the nested projections 14, 14A, 14B together, such as in the first preferred tip 24 with the greater tip angle Q than the projection angle D, wherein the sides 25a contact the intersection between the top wall or surface l4a and the sidewall l4b of the projection 14, 14 A. The resulting weld 15 of the sidewalls l4b and the top surfaces l4a of the projections 14, 14A, 14B has limited increase in strength over welding mostly the sidewalls l4b' of the projections 14', 14 A',

14B', such as in the second preferred embodiment. The increased surface or area of the weld 15, 15' would generally not increase the perimeter length of the weld 15, 15' exposed to tensile forces and, therefore, may be essentially equal for the two configurations. The difference would be in the elongation of the connection before final failure, which may happen long after the peak force is achieved. The perimeter of the weld 15, 15' where the high stress is developed at the interface between the sheets 12, 12A, 12B, 12 A', 12B' would generally be the determining factor for the ultimate strength of the weld 15, 15'. The concept of welding the top surfaces l4a and sidewalls l4b in the first preferred embodiment may be difficult due to variations in manufacturing that would cause the tip 24 with the depression 25 to not always be in contact simultaneously with both the sidewalls l4b and the top surface l4a of the projection 14, 14A. Under conditions where the tip 24 does simultaneously contact the sidewalls l4b and top surfaces l4a of the projection 14, 14A with the sides 25a of the depression 25, the potential for“oil canning” related to bum through of the material if the sheet 12, 12 A, 12B at the side-top interface may be a concern, although the projections 14, 14A, 14B, the tip 24 and method may be developed to define the weld 15 along both the sidewalls l4b and the top surfaces l4a of the projections 14, 14A, 14B. Several different gauges of material for the sheets 12, 12A, 12B, 12 A', 12B' are produced for typical fill, pack and assembled sheet products, which may require different designs for these various gauges to limit the variation in the weld performance, thereby increasing the capital investment in ultrasonic welding tips 24, 24', 54.

[0036] In another preferred configuration and method for a weld design utilizing the preferred single-sided ultrasonic welding mechanism 10 for connecting the sheets 12, 12A, 12B, 12 A', 12B' is to design and deploy a horn or tip 23, 24 that contacts or engages at least some of the projection 14, 14A, 14B, 14 A', 14B' to provide alignment and some weld surface area, but also to weld at an intersection of the projection 14, 14 A, 14B, 14 A', 14B' and the sheet 12, 12 A, 12B, 12 A', 12B' or at the base of the projection 14, 14A, 14B, 14 A', 14B' around the projection 14, 14A, 14B, 14 A', 14B' so as to increase weld surface area and reduce the potential for increased movement or deflection at the weld by attaching some of the sheets 12, 12A, 12B, 12 A', 12B' at or along the sheet plane 28,

28'. This variety of weld is an artifact of the pressure applied and the interference between the projection 14, 14A, 14B, 14 A', 14B' and the horn 23 or tip 24, 24', 54, as well as relates to the design and configuration of the projections 14, 14A, 14B, 14 A', 14B' relative to the hom 23 or tip 24, 24', 54. Additional pressure or reduced interference between the horn 23 or tip 24, 24', 54 and the nested projections 14, 14A, 14B, 14 A', 14B' preferably causes contact of the base or distal surface of the horn 23 or tip 24, 24', 54 with the base or bottom portion of the projection 14, 14 A, 14B, 14 A', 14B', providing some degree of welding as this area is also stabilized by the projection 14, 14 A, 14B, 14 A', 14B'.

[0037] Another preferred aspect of ultrasonically welded design is the orientation of the weld which would also affect the results, configuration and performance of the welded sheets 12, 12A, 12B, 12 A', 12B'. In a non-limiting preferred example, a flat weld in the sheet plane 28 of the sheets 12, 12 A, 12B, 12 A', 12B' would concentrate stress at the interface of the sheets 12, 12 A, 12B, 12 A', 12B' when forces are applied pulling apart the sheets 12, 12A, 12B, 12 A', 12B'; however, a weld between the sidewalls l4b, Mb' of the projections 14, 14A, 14B, 14 A', MB' would orient the weld generally perpendicular to the sheet plane 28, 28' thereby leading to shear in the projection 14, 14 A, 14B, 14 A', MB', not tensile stress at the weld perimeter of the interface. The projections 14, 14A, 14B, 14 A', MB' would mechanically deform to change the orientation of the weld to begin to peel at the perimeter of the weld to then act similarly to the relatively flat weld described in alternative embodiments described above.

[0038] Ultrasonic welding of thicker injection molded parts may utilize an energy director (not shown), which is a rib or feature molded into one of the parts being joined to define a repeatable contact area for ultrasonic welding between the parts. The energy director may be comprised of a v- shaped cross-sectional feature that is included between the mating surfaces of the parts being ultrasonically welded, generally protruding from the part in the direction of contact with the horn 23 or tip 24, 24', 54. The energy director is designed and configured to concentrate the ultrasonic energy to rapidly soften and melt the small amount of material of the energy director to form a weld between the parts. The energy director can be applied in the design of the projections 14, 14A, 14B, MA', MB' of the sheets 12, 12A, 12B, 12 A', 12B' used to automate the welding process. In a non limiting preferred example, if the horn 23 or tip 24, 24', 54 contacts the top surface Ma or an intersection of the top surface Ma and the sidewall Mb of the projections 14, 14 A, 14B first during use due to a more obtuse tip angle Q of the sides 25a of the depression 25 in comparison to the projection angle D of the projections 14, 14A, 14B, the energy is concentrated at a point of first contact and progresses down the projection 14, 14 A, 14B as pressure and melting of the top surfaces Ma and top portions of the sidewalls Mb causes reduction to a height of the projections 14, 14A,

14B because of the softened material of the projection 14, 14 A, 14B and progressive contact occurs between the tip 24 and the nested projections 14, 14 A, 14B. The general limit of the weld 15 formed by this method would depend upon the difference in the projection angles D of the projection 14, 14A, 14B, the tip angle Q of the tip 24, the length of time for forming the weld 15 and additional related factors related to the method and the single-sided ultrasonic welding mechanism 10. The longer the contact time between the tip 24 and the projections 14, 14 A, 14B, the higher the temperature of the preferred polymeric material being welded, thereby lending itself to the degradation of the material being welded, such as the preferred PVC material or an also preferred polypropylene (PP) material. Although other materials may be utilized for the sheets 12, 12A, 12B, 12 A', 12B' and the projections 14, 14A, 14B, 14 A', 14B' and for single-sided welding and meet the requirements for connecting the sheets 12, 12A, 12B, 12 A', 12B' and joining the fill, packs and sheet assemblies, the PVC is relatively susceptible to degradation due to elevated temperatures generated during ultrasonic welding. In addition, chlorine molecules of the PVC may cleave from the polymer backbone at higher temperatures. The chlorine molecule of the PVC may combine with water vapor in the air to form hydrogen chloride (HC1) which is considered corrosive and a hazardous material in certain environments and concentrations.

[0039] In the preferred embodiments, the sheets 12, 12A, 12B, 12 A', 12B' with the projections 14, 14A, 14B, 14 A', 14B' are designed and configured for connection via MA, as is described in the ‘628 patent, and via the welding techniques described herein utilizing the single-sided ultrasonic welding mechanism 10 and techniques of the preferred embodiments. The sheets 12, 12A, 12B,

12 A', 12B' can, therefore, be assembled via mechanically crushing or deforming the nested projections 14, 14A, 14B, 14 A', 14B' and/or by welding the nested projections 14, 14A, 14B, 14 A', 14B' together, typically without modifying the design or configuration of the projections 14, 14 A, 14B, 14A', 14B' or the sheets 12, 12A, 12B, 12 A', 12B'. In all of the methods for joining the sheets 12, 12A, 12B, 12 A', 12B', the nestable projections 14, 14A, 14B, 14A', 14B' stabilize the section of plastic sheets 12, 12A, 12B, 12 A', 12B' relative to each other to facilitate welding or mechanical joining and facilitate the welding and mechanical assemblies, as would be apparent to one having ordinary skill in the art based on a review of the present disclosure.

[0040] Typically, for MA of thermoformed sheets 12, 12A, 12B, 12 A', 12B', the projections 14, 14A, 14B, 14 A', 14B' are staggered or offset down a length of the sheets 12, 12A, 12B, 12 A', 12B' to limit the peak force required to crush the projections 14, 14A, 14B, 14 A', 14B', that is, the number of projections 14, 14 A, 14B, 14 A', 14B' contacted by the mechanical wheel described in the‘628 patent across a width of the sheets 12, 12A, 12B, 12 A', 12B' is reduced to enable manual turning of the crank to mechanically assemble the fill, packs or sheet assemblies. With an offset edge and internal projections 14, 14A, 14B, 14A', 14B', a thermoforming tool (not shown) can be modified to have inserts (not shown) that can adjust to align the nested or assembled projections 14, 14A, 14B, 14A', 14B' across the sheets 12, 12A, 12B, 12 A', 12B' to facilitate ultrasonic welding utilizing the preferred single-sided ultrasonic welding mechanism 10. The offset of the projections 14, 14A,

14B, 14 A', 14B' allows for sequential crushing of the nested projections 14, 14A, 14B, 14 A', 14B' to minimize the peak force required by the assembly machine for assembly. The alignment across the width of the sheets 12, 12A, 12B, 12 A', 12B' would be desired for automation of the ultrasonic welding mechanism 10 to eliminate“dry firing” of the tip 24, 24', 54 where all of the tips 24, 24', 54 are not simultaneously in contact with the sheets 12, 12A, 12B, 12 A', 12B', such as where multiple tips 24, 24', 54 simultaneously engage nested projections 14, 14A, 14B, 14 A', 14B' to assemble sheets 12, 12 A, 12B, 12 A', 12B' and certain of the tips 24, 24', 54 are not in engagement with nested projections 14, 14A, 14B, 14 A', 14B', such as for connecting sheets 12, 12A, 12B, 12 A', 12B' having a smaller size than the capacity of an automated bank or collection of tips 24, 24', 54. This dry firing can reduce the life of or damage the tips 24, 24', 54, thereby causing stress cracks to form in the tips 24, 24', 54 from unused vibrational energy. If the positioning or offset of the projections 14, 14A, 14B, 14A', 14B' is not addressed in the thermoform tool or mechanism design with the insert to shift the offset to an aligned position across the width of the sheet 12, 12 A, 12B, 12 A', 12B', the welding could be accomplished sequentially across the width one column at a time or be

programmed to offset each successive row of projections 14, 14A, 14B, 14 A', 14B' in the control scheme for the product assembly. This design and operation would preferably include a change in machine design that enables the offset to be addressed by moving the tips 24, 24', 54 down the length of the sheet 12, 12A, 12B, 12 A', 12B' to ensure that the entire length of the tips 24, 24', 54 is in contact with the sheet 12, 12A, 12B, 12 A', 12B' or projection 14, 14A, 14B, 14 A', 14B'. The typical design of the thermoformed sheet 12, 12 A, 12B, 12 A', 12B' contains more edge projections 14, 14A, 14B, 14A', 14B' than internal projections 14, 14A, 14B, 14A', 14B', that is, the period of the corrugations begins and ends based on the edge geometry and the internal projections 14, 14 A, 14B, 14 A', 14B' usually differs in that the last projection 14, 14A, 14B, 14 A', 14B' is not generally present. The number of edge projections 14, 14A, 14B, 14 A', 14B' (N) is typically greater that the number of internal projections 14, 14A, 14B, 14A', 14B' on a sheet 12, 12A, 12B, 12 A', 12B' by one (N-l). If the offset or lack of feature remains, the index length of the interior projection welding tips 24, 24', 54 would either cause the projections 14, 14 A, 14B, 14 A', 14B' not to be welded fully down the length of the sheet 12, 12A, 12B, 12 A', 12B' ( e.g ., skipped projections) or the tip 24, 24', 54 would hang off the end of the sheet 12, 12A, 12B, 12 A', 12B' for the final weld sequence. By not contacting the tip 24, 24', 54 to the sheet 12, 12A, 12B, 12 A', 12B' or projections 14, 14A, 14B,

14 A', 14B' in full, the unused vibrational energy could damage the tip 24, 24', 54 through fatigue failure and is not preferred, although a certain amount of unused tip 24, 24', 54 firing may be tolerated without significantly impacting the function and operation of the single-sided ultrasonic welding mechanism 10. One preferred tip 24, 24', 54 in the sequence of tips 24, 24', 54 that may be utilized with an automated assembly mechanism and may have a different design than other tips 24, 24', 54 to interact with specifically designed projections 14, 14A, 14B, 14 A', 14B'. The tips 24, 24', 54 may be specifically designed for the particular nested projections 14, 14A, 14B, 14 A', 14B' that are being welded with the tips 24, 24', 54 such that numerous differently designed tips 24, 24', 54 are utilized with the preferred single-sided ultrasonic welding mechanism 10 and several different designs may be utilized with a particular automated assembly mechanism to assembly multiple sheets 12, 12A, 12B, 12 A', 12B' into fill, pack or otherwise assembled sheets 12, 12A, 12B, 12 A', 12B'.

[0041] The preferred single-sided ultrasonic welding mechanism 10 may be utilized to connect the sheets 12, 12A, 12B, 12 A', 12B' that have a configuration that is the same or substantially the same as the contact sheets described in the‘628 patent that are mechanically crushed or

mechanically assembled to secure the sheets 12, 12A, 12B, 12 A', 12B' together. The sheets of the ‘628 patent, which may be comprised as the sheets 12, 12A, 12B, 12 A', 12B', are designed to a specific corrugation or flute period to limit an investment in MA equipment for the potentially infinite number of flute periods, the preferred sheets 12, 12 A, 12B, 12 A', 12B' are preferably similarly designed to take advantage of the same concept for ultrasonic welding utilizing the single- sided ultrasonic welding mechanism 10. The preferred ultrasonic tips 24, 24', 54 are designed to align with the flute cycle and concentrate the projections 14, 14A, 14B, 14 A', 14B' on the sheets 12, 12A, 12B, 12 A', 12B' down the length of the tips 24, 24', 54, as opposed to potential large spacing of the projections 14, 14A, 14B, 14 A', 14B' across a width of the sheets 12, 12A, 12B, 12 A', 12B'. Utilizing the preferred single-sided ultrasonic welding mechanism 10 with automation, weld cycle times for connecting the first sheet 12A, 12 A' to the second sheet 12B, 12B' can be reduced due to a reduction in motion and indexing required to weld all the available nested projections 14, 14 A, 14B, 14 A', 14B' through automation. A preferred tip 24, 24', 54 that hits more nested projections 14,

14 A, 14B, 14 A', 14B' will have fewer movement cycles to weld or connect the same number of nested projections 14, 14A, 14B, 14 A', 14B'. The tips 24, 24', 54 may be comprised of composite tips 24, 24', 54 designed to function across a width of the sheets 12, 12 A, 12B, 12 A', 12B', which could increase the cost of the welding equipment because of the increased number of weld positions and thus assembly cycle times. Each product family defined by the same flute cycle would, therefore, preferably use the same bar tip 24, 24', 54 design to assemble multiple products, thereby limiting the capital investment in ultrasonic equipment. Essentially, the products are then preferably designed around the configuration of the tips 24, 24', 54 and the single-sided ultrasonic welding mechanism 10 to reduce investment in machinery for assembly.

[0042] The ability to have a single thermoforming tool that produces the preferred sheets 12,

12 A, 12B, 12 A', 12B' that facilitate mechanical and ultrasonic welding of the projections 14, 14 A, 14B, 14 A', 14B' to engage or connect the sheets 12, 12A, 12B, 12 A', 12B' is that the sheets 12, 12A, 12B, 12 A', 12B' are able to service the market with either connection method, depending upon which is preferred by the customer and/or which has the lower cost based on site specific information such as availability of power or shipping costs. In addition, products would be able to be produced in materials such as polypropylene that can generally not be solvent bonded, thereby enabling alternative materials to be used in manufacture of the sheets 12, 12A, 12B, 12 A', 12B' used for pack assembly.

[0043] Referring to Figs. 4-4A, the MA and gluing of fill products and pack assemblies does not always result in ideal connections between the successive sheets 12, 12A, 12B, 12 A', 12B' of the assembly. Repairs are required from time to time for both mechanically assembled projections 14, 14A, 14B, 14 A', 14B' and gluing or adhesive bonding of the nested projections 14, 14A, 14B, 14 A', 14B' in the manufacturing process. A current repair method to correct improperly connected projections 14, 14A, 14B, 14 A', 14B' is to apply a solvent and filler-based material or glue with a “fast food ketchup dispenser”-type bottle. The solvent evaporates and diffuses through both the sheets 12, 12A, 12B, 12 A', 12B' being repaired and the resin present in the mixture. This method of repair is relatively messy and requires an environmental permit for Volatile Organic Compound (VOC) emissions. It is desirable to eliminate glue and solvent from the factory environment to facilitate“green” manufacturing and to eliminate the cost of the environmental permits. A fill pack repair tool that does not utilize solvent is, therefore, desirable. Thermal welding of the edges of fill packs to repair the packs and assembled sheets 12, 12A, 12B, 12 A', 12B' and improve product quality can be used; however, the dwell time for the heat to conduct from the resistive heating element in the tip through the material to the interface is not conducive to a rapid paced

manufacturing environment. Ultrasonic welding in accordance with the preferred single-sided ultrasonic welding mechanism 10 and related methods can typically be achieved at a faster rate. It would be desirable to conduct ultrasonic welding for repair of fill packs or assembled sheets 12,

12 A, 12B, 12 A', 12B' without the anvil utilized for two-sided ultrasonic welding to decrease the cycle time for each repair location on the cooling tower fill pack or sheet assemblies. [0044] An ultrasonic tip 74 in accordance with a fourth preferred embodiment with a V-shaped groove 75 cut into a distal end of the tip 74 in line with a longitudinal axis 76 of the tip 74 can be used to apply pressure to both sides of a defect in a connection of the sheets 12, 12 A, 12B, 12 A',

12B' to ultrasonically weld and connect the sheets 12, 12 A, 12B, 12 A', 12B'. The pressure applied to a sheet edge 78 of two adjacent sheets 12, 12A, 12B, 12 A', 12B' is generated by having the V- shaped groove or slot 75 that begins at a wide opening 75a, preferably at twice the maximum gauge desired to be repaired to a smaller butt end 75b of the slot or groove 75 that is preferably the dimension at a single sheet 12, 12A, 12B, 12 A', 12B' of the minimum gauge that may be desired to be repaired. The fourth preferred tip 74, which may be utilized with the ultrasonic welding mechanism 10 of the first preferred embodiment includes a threaded stem 74A at a proximal end that is removably mountable to the horn 23. The opening 75 may alternatively be integrally formed on the horn 23 and include an integrally formed handle on the horn 23 or may be otherwise configured. The V-slot groove 75 of the tip 74 is applied to the connection retaining both sheets 12, 12A, 12B, 12 A', 12B' within the groove 75 so far as the sheets 12, 12A, 12B, 12 A', 12B' will enter the opening 75a based on a nominal, preferably non-destructive, force applied to the tip 74 by a handle, such as a handheld ultrasonic welder (not shown). The welder is preferably activated to drive the horn 23 and the tip 74 and the sheet edge 78 of the sheets 12, 12A, 12B, 12 A', 12B' are connected between the opposing sides of the V-shaped groove 75. The repair tip 74 can be incorporated into an automated machine that welds a plurality of sheets 12, 12 A, 12B, 12 A', 12B' into a full pack or sheet assembly, but uses this technology to weld the sheet edges 78 of the pack. This repair tip 74 can be used in a continuous welding process to provide pressure to both sides of adjacent sheet 12, 12A, 12B, 12 A', 12B' that are desired to be sealed or connected, thereby creating a repair weld 79. The tip 74 is moved down the edges of the adjacent sheet 12, 12A, 12B, 12 A',

12B' with relatively constant pressure and force can be applied inwardly on the sheet edges 78, either manually or automatically based on known welder setpoints and welding speeds down the edges 78 of the sheets 12, 12A, 12B, 12 A', 12B'. The repair tip 74 may also be utilized in combination with MA of nested projections 14 and ultrasonic welding of nested projections 14,

14A, 14B, 14A', 14B' to construct the fill or assembled sheets 12, 12A, 12B, 12 A', 12B'. The opening 75a preferably defines an opening gap 80 that accommodates receipt of the thickness of the sheets 12, 12A, 12B, 12 A', 12B' therein with the groove 75 being open at its sides. The opening gap 80 is preferably greater than double a thickness of the first sheet 12A, 12 A' so that the sheets 12,

12 A, 12B, 12 A', 12B' may be accepted into the groove 75 during operation of the tip 74 of the fourth preferred embodiment. The groove 80 also preferably defines a groove angle W relative to the longitudinal axis 76 between the butt end and the opening 75a. The groove angle W is preferably in the range of approximately two to ten degrees (2-10°) in the fourth preferred embodiment, but is not so limited. The butt end of the groove 75 preferably has a butt height 82 that is approximately equal to a thickness of the first sheet 12A, 12 A', but is not so limited and may be larger or smaller, as long as the groove 75 is designed and configured to produce the repair weld 79 that connects the first and second sheets 12A, 12B, 12 A', 12B' at the sheet edge 78.

[0045] Referring to Figs. 5 and 5A, an ultrasonic welding tip 524 in accordance with a fifth preferred embodiment of the present invention has similar features and functionality compared to the welding tips 24, 24' of the first and second preferred embodiments and similar reference numerals are utilized to identify the similar features with a“5” prefix utilized to distinguish the features of the fifth preferred tip 524 from the first and second preferred tips 24, 24'. The fifth preferred tip 524 includes a threaded stem 524a and a distal end 524c with an X-shaped groove 524b formed in the distal end 524c. The X-shaped groove 524b mates with a first alignment feature 514 on a first sheet 512 to ultrasonically weld the first alignment feature 514 to a mating second alignment feature nested into the first alignment feature 514 on a second sheet (not shown). The first alignment feature 514 and the second alignment features of the fifth preferred embodiment is comprised of an X-shaped projection that extends from the first and second sheets 512, but is not so limited. The first and second alignment features 514 may be comprised of nearly any feature that is designed and configured to align and stabilize the first sheet relative to the second sheet and can be ultrasonically welded to secure the first sheet to the second sheet 512. For example, the first and second alignment features 514 may be comprised of X-shaped depressions in the nested sheets 512, dome-shaped dimples formed in the sheets 512 or nearly any shape or feature in the sheets 512 that may be engaged to align the first and second sheets 512 and may be welded together utilizing an ultrasonic horn or tip. The first and second alignment features 514 are preferably spaced from edges of the sheets 512 such that they are considered inner alignment features.

[0046] It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the present disclosure.

Claims

CLAIMS We claim:

1. A system for defining assembled polymeric fill or pack products allowing fluid and air flow therethrough, the system comprising:

a first sheet having a first projection extending therefrom, the first projection extending from the first sheet at a first projection angle;

a second sheet having a second projection extending therefrom, the second projection extending from the second sheet at a second projection angle, the first projection angle being substantially equal to the second projection angle, the second projection being nestable within the first projection in a nested configuration; and

an ultrasonic welding tip having a depression at a distal end with a butt end spaced from the distal end, the depression having sides extending at a tip angle relative to a longitudinal axis of the tip, the depression configured to mate with the first projection to ultrasonically weld the nested first and second projections and connect the first sheet to the second sheet.

2. The system of claim 1, wherein the projection angle is approximately fifteen degrees and the tip angle is approximately eighteen degrees.

3. The system of claim 1, wherein the depression has an upper section and a fillet section.

4. The system of claim 3, wherein the upper section has a frusta-conical shape.

5. The system of claim 1, wherein the tip, the first projection and the second projection are configured to define a cavity between a first top surface of the first projection and the butt end of the depression.

6. The system of claim 1, wherein the tip, the first projection and the second projection are configured such that the butt end of the depression is in engagement with a first top surface of the first projection when the tip is ultrasonically welding the first projection to the second projection.

7. The system of claim 1, wherein the first and second sheets are constructed of a polyvinyl chloride material.

8. The system of claim 1, wherein the first sheet is constructed of a polyvinyl chloride material and the second sheet is constructed of a second polymeric material.

9. The system of claim 8, wherein the second polymeric material is a polypropylene material.

10. The system of claim 1, wherein the first and second sheets are constructed of a polypropylene material

11. The system of claim 1, wherein the first and second sheets define a sheet plane in the nested configuration, the first and second projections and the depression configured such that a weld connecting the first sheet to the second sheet is positioned one of on and adjacent to the sheet plane.

12. The system of claim 1, wherein the tip is integrally formed on an ultrasonic horn.

13. An ultrasonic welding system for connecting first and second sheets having first and second frusta-conical projections, the ultrasonic welding system comprising:

a power supply;

a converter in communication with the power supply;

a booster in communication with the converter;

a controller in communication with the power supply, the converter and the booster; and a horn connected to the booster; and

a tip connected to the horn, the tip including a depression extending along a longitudinal axis from a distal end of the tip to a butt end, the controller configured to introduce an ultrasonic vibration into the horn and the tip, the depression configured to engage the first projection when the first and second projections are in a nested configuration to form an ultrasonic weld between the first and second projections to connect the first and second sheets.

14. The ultrasonic welding system of claim 13, wherein the depression includes sides, the sides defining a tip angle, the tip angle being approximately eighteen degrees.

15. The ultrasonic welding system of claim 13, wherein the depression includes an upper section and a fillet section, the fillet section positioned proximate the distal end of the tip.

16. The ultrasonic welding system of claim 13, wherein the tip is constructed of a metallic material.

17. The ultrasonic welding system of claim 13, wherein the butt end extends substantially perpendicular to the longitudinal axis.

18. The ultrasonic welding system of claim 13, wherein the tip includes a threaded stem at a proximal end, the threaded stem removably connectable to the horn.

19. An ultrasonic welding system for connecting first and second sheets having first and second edges, the ultrasonic welding system comprising:

a power supply;

a converter in communication with the power supply;

a booster in communication with the converter;

a controller in communication with the power supply, the converter and the booster;

a horn connected to the booster; and

a tip connected to the horn, the tip including a V-shaped groove extending along a longitudinal axis from a distal end of the tip to a butt end, the controller configured to introduce an ultrasonic vibration into the horn and the tip, the groove configured to engage the first and second edges to form an ultrasonic weld between the first and second edges to connect the first and second sheets.

20. The ultrasonic welding system of claim 19, wherein the groove includes a wide opening at the distal end.

21. The ultrasonic welding system of claim 20, wherein the wide opening has an opening gap, the opening gap greater than double a thickness of the first sheet.

22. The ultrasonic welding system of claim 19, wherein the V-shaped groove is open at sides of the tip.

23. The ultrasonic welding system of claim 19, wherein the V-shaped groove defines a groove angle, the groove angle being approximately two to ten degrees.

24. The ultrasonic welding system of claim 19, wherein the butt end has a butt height, the butt height being approximately equal to a thickness of the first sheet.

25. A system for defining assembled polymeric fill or pack products allowing fluid and air flow therethrough, the system comprising:

a first sheet having a first alignment feature thereon, the first alignment feature spaced from first edges of the first sheet; a second sheet having a second alignment feature thereon, the second alignment feature spaced from second edges of the second sheet, the first alignment feature spaced from second edges of the second sheet in an assembled configuration, the first alignment feature in engagement with the second alignment feature in the assembled configuration; and

an ultrasonic welding horn having a tip designed and configured to engage the first alignment feature in a welding configuration with the tip contacting the first alignment feature to ultrasonically weld the engaged first and second alignment features and connect the first sheet to the second sheet in the assembled configuration.

26. The system of claim 25, wherein the first alignment feature is a first projection and the second alignment feature is a second projection.

27. The system of claim 26, wherein the first and second projections have a frusta-conical shape.

28. The system of claim 25, wherein the first and second sheets are constructed of a PVC material.

29. The system of claim 25, wherein the tip includes a depression.