Pedestal mounted ultrasonic welding device

The sonotrode and anvil of co-pending application Ser. No. 12/925,652, for advanced ultrasonic welding of work pieces, are readily incorporated into new form-fill-seal machines, but existing machines with heat-seal stations pose difficult problems for swapping of the sealing packages. Kits enabling heat station replacement, with the further improved sonotrode and anvil disclosed herein, comprise: a housing; a linear rail fixed thereto; anvil and sonotrode support members; and a parallel gripper. Each of the anvil and sonotrode support members is slidably attached to the rail(s) and are also connected to a respective piston of the gripper, permitting actuation of each through cycling of the gripper pistons. The improved sonotrode/anvil combination each comprise a corresponding plurality of energy directors arranged into a three-dimensional grid pattern to produce a narrower weld region, but one exhibiting greater durability, thereby permitting use of less packaging material, and which may also weld a company logo into the workpieces.

FIELD OF THE INVENTION

The present invention relates to improvements in form-fill-seal machines, and more particularly to apparatus which are capable of being retrofit onto such machines to improve the machine's productivity through replacement of old-technology heat-sealing elements using a kit comprising an advanced ultrasonic welding stack and anvil.

BACKGROUND OF THE INVENTION

The packaging of food and other products with a sheet of flexible plastic film through an automated process using a machine is typically achieved by butting and sealing the plastic film to form a pouch. There are numerous examples of such machines, which are referred to within the industry as form-fill-seal machines (“FFS machines”), and which may be further subdivided into categories as being either horizontal, vertical, or rotary form-fill-seal machines. An example of a horizontal form-fill-seal machine is shown by U.S. Pat. No. 5,826,403 to Haley; an example of a vertical form-fill-seal machine is shown by U.S. Pat. No. 4,117,647 to Rossi; while an example of a rotary form-fill-seal machine is shown by U.S. Pat. No. 6,212,859 to Bielik.

For a substantial period of time, these form-fill-seal machines utilized heat elements, such as the “heated fin wheels” of the Haley device, to seal the package bottom and its side seam to create a pouch, and after filling that pouch with product, a final heat element would seal the top open end of the pouch to form the package. An early marriage of ultrasonic welding principles for sealing of plastic films with a packaging machine is shown by the 1981 U.S. Pat. No. 4,288,965 to James, for a “Form-Fill-Seal Packaging Method and Apparatus.” Ultrasonic welding has since become the preferred method of sealing, because, among other reasons, ultrasonic weld times are less than one second in duration, the process lacks the potential for damage to the packaging material or product from an excessive application of heat, for which traditional heating elements are susceptible, and because the ultrasonic welding process is much better suited to seal through contaminants and product, which the heat sealing process accomplishes poorly, if at all.

Our above-noted co-pending U.S. patent application Ser. No. 12/925,652 for “Sonotrode and Anvil Energy Director Grids for Narrow/Complex Ultrasonic Welds of Improved Durability,” furthers this divide. The technology disclosed therein makes even more advantageous the use of ultrasonic welding over heating elements, as it reduces the necessary material, by allowing for a narrower weld, while also simultaneously producing welds of improved durability, which is highly desirable particularly for the packaging of liquid, semi-liquid, and even for the packaging of solids or semi solid products. Of course, the process could still be used to produce wider welds, where they may be desired, for example for aesthetic purposes, rather than for being needed to produce a stronger, more durable seal.

However, while that patent-pending technology may easily be incorporated into newly designed form-fill-seal packaging machines, consumers who either recently or long ago purchased machines that seal through the direct application of heat have been at an impasse. The owner's of those machines do not wish or simply cannot afford the expense of a new array of packaging machines, nor can they afford to not produce packaging with the durability that their competitors will soon be utilizing through the use of machines incorporating this new apparatus. The problem has one added dimension of complexity.

The different types of packaging machines may dictate forming the pouch in different stages and at different locations within the machine. In addition, it is common to have at least one or even multiple heat seal stations just for the final top end sealing of multiple product-filled pouches. Therefore, it is highly desirable to incorporate our patent-pending ultrasonic welding technology onto existing machines, but attempts to accomplish such a retro-fit by package machine operators has been unsuccessful, because of the space-constrained volume allocated to the replacement unit. The current invention discloses an adaptable retrofit kit and method for successfully accomplishing retrofitting of the heat station for different kinds of form-fill-seal machines.

OBJECTS OF THE INVENTION

It is an object of the invention to provide a means of retrofitting the heat station of a form-fill-seal machine with advanced ultrasonic welding equipment.

It is another object of the invention to provide a means of retrofitting a space-constrained volume of a form-fill-seal or pre-made pouch type machine with a kit comprising advanced ultrasonic welding equipment.

It is a further object of the invention to provide a versatile retrofit kit for replacing a heat station with a kit comprising advanced ultrasonic welding, for either a horizontal or a rotary type of form-fill-seal or pre-made pouch type machine.

It is another object of the invention to provide a retrofit kit for advanced ultrasonic weld sealing of two or more product pouches simultaneously.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings.

SUMMARY OF THE INVENTION

Advanced ultrasonic welding components of our co-pending application Ser. No. 12/925,652 are readily incorporated into the design of new form-fill-seal machines, but the owners of older machines, which utilize heat-seal stations, were unsuccessful at devising suitable apparatus and methods for retrofit of the sealing equipment. A retrofit that adeptly replaces the older heat sealing station of either horizontal or rotary form-fill-seal machines, with an advanced ultrasonic sonotrode and anvil of our co-pending application, may comprise the following kit: a housing; a linear rail fixed to the housing; at least first and second bearing carriages being slidable upon the rail; and first and second fluidic muscles. Each of the fluidic muscles may be mounted with a first end being fixed to a respective housing wall, and a second end being fixed to a respective bearing carriage. Attachment to the respective bearing carriage may be through attachment of each muscle to a respective mounting member that may be fixed to respective mounting blocks, which are then fixed to the bearing carriages. The advanced anvil and sonotrode may be secured to respective carriages.

Actuation of each carriage may be through the pressurization of the fluidic muscles, which in turn causes cyclic expansion of the chamber of each muscle, which is accompanied by linear contraction along its length. The contraction of each fluidic muscle causes simultaneous converging translation of the first and second mounting members relative to the linear rail, to cause engagement of a surface of the anvil with a surface of the sonotrode. Synchronizing the electrical power for the stack to correspond to this period of engagement, permits sealing of pouches, which move along a conveyor or a rotary dial, while they are positioned between the anvil and sonotrode. Depressurization of the fluidic muscles causes reverse translation and disengagement of the anvil from the sonotrode, after which the conveyor or rotary dial may advance to cause exiting of the sealed pouch, and positioning of another unsealed pouch between the anvil/sonotrode combination.

Specially configured in-line arrangements of the anvil/sonotrode, the bearing carriages, the first fluidic muscle, and the second fluidic muscle, serve to provide a very narrow profile, which permits side-by-side kit installations for a retrofit that accomplishes duplex, triplex, or more sealing of pouches on a horizontal machine.

DETAILED DESCRIPTION OF THE INVENTION

Initial attempts by package machine operators to retrofit existing form-fill-seal machines with the ultrasonic welding technology of our co-pending application Ser. No. 12/925,652, were unsuccessful. The volume that could be occupied by the retrofit apparatus was extremely constrained. This constraint was exacerbated by the scenario where a duplex or triplex sealing operation was required at the heat station. A single large horn and anvil being moved to engage each other using conventional actuators were too slow to achieve satisfactory results or outside the realm of single width ultrasonic horn technology. Using two different pairs of horn/anvil combinations was unsatisfactory because of the difficulty in calibrating synchronous engagement of the pairs while the forces generated were too small, and resort to a servo-motor was considered for synchronization, but found to be overly expensive for the application, as it would diminish its marketability.

FIG. 1shows a perspective view of a first embodiment of the retrofit kit10of the present invention, which elegantly overcame these obstacles, being shown with a housing side panel23removed to expose the actuation portion of the invention.

The device utilizes a pair of fluidic mechanical muscles in a specially created dual linear mechanism for simultaneous actuation of both the anvil and the horn/booster/converter stack. Today's “Fluidic Muscle,” as it is commonly termed (along with pneumatic artificial muscle), is in part the progeny of an invention by Richard Gaylord. Gaylord, in 1955, received U.S. Pat. No. 2,844,126 for a “Fluid Actuated Motor System and Stroking Device.” In general, a fluidic muscle may be constructed by wrapping a synthetic or natural rubber tube with a woven sheath. This forms an expansible chamber. When a pressurized fluid is applied to the chamber of the fluidic muscle, the chamber expands radially and is accompanied by a corresponding contraction in its length, resulting in linear motion. Metallic or plastic fittings may be secured at both ends to transmit the resultant motion.

The retraction strength of the muscle may be determined by the total strength of the individual fibers forming the woven sheath, while its exertion distance may be determined according to the tightness of the weave, where a looser weave may allow greater bulging, resulting in further twisting of the individual fibers in the weave. Fluidic muscles for use with the current invention may be obtained from the Festo Corporation, located in Mt. Prospect, Ill. (see www.festo.com).

Fluidic muscles are commonly utilized in pairs—one agonist and one antagonist, where the antagonist acts in opposition to the motion of the agonist, thereby mimicking the functioning of muscles within the human body (e.g., an extensor muscle that opens a joint and a flexor muscle to act in opposition to close the joint). However, in this invention, the fluidic muscles operate in a different mode.

In the simplest possible embodiment, a single fluidic muscle may be used to replicate the linear motion provided by the press190in a typical prior art ultrasonic welding machine100, represented inFIGS. 13A and 13B. However, in practice, this is not very conducive to the successful retrofitting of many form-fill-seal machines, particularly for a horizontal type machine. In such machines, because the pouch(s) may translate along a conveyor towards a heat station (see e.g., packaging machine 5 in FIG. 1 of U.S. Pat. No. 5,826,403 to Haley), where one or more heating elements may converge upon the pouch(s) to seal it, it is highly desirable to impart motion to both the anvil and the sonotrode. This dual motion may be set so as to have the sonotrode and anvil generally converge at the mid-plane of the opening to thereat apply pressure and vibration energy necessary for localized heating and melting of the plastic film to seal the opening.

A first embodiment of the present invention is shown by the retrofit kit10inFIG. 1(with a side panel23of the housing removed), and is also shown inFIG. 2. The retrofit kit10, which may be used in the replacement of one or more heat sealing elements of either a horizontal or a rotary form-fill-seal machine, may include a housing having a base20, a first end wall21, a second end wall22, a first side wall23, and a second side wall24. The housing may also comprise a mid-wall26. Many of these components are common to a later discussed embodiment, for which an exploded view is shown inFIG. 7, so reference thereto may be advantageous. The housing side panels23and24may be used to enclose and protect the fluidic muscles, along with the base20and end walls21and22, and in addition, an optional cover (not shown) may be used for those reasons as well. Also, side panels23and24may serve to add structural rigidity to the housing; however, the panels23and24are not required for supporting the functionality of the mechanism, as will be seen hereinafter.

The base20may have a first opening20A and a second opening20B, both of which may be slotted openings. A first mounting member30may have a portion being disposed part-way through the first opening20A in base20. In one embodiment, first mounting member30may preferably be “L”-shaped, and may have one leg31of the “L” protruding up through the opening20A in base20, and the other leg32may be disposed so as to generally parallel the base20of the housing. The first mounting member30may therefore be slidable within the slotted opening20A of the base20of the housing. A second mounting member40may be similarly constructed with first and second legs41and42, and be correspondingly disposed so as to be slidable within the second opening20B in the base. The ends of the second legs32and42of the “L”-shaped mounting members may face each other within the kit assembly.

The second legs32and42of the “L”-shaped mounting members30and40may each be attached to at least one respective bearing carriage, which may be slidable upon a linear rail. In a preferred embodiment, a linear rail with four bearing carriages being slidable thereon may be used. Linear rails and bearing carriages are commercially available, and may be obtained from PBC Linear, in Roscoe, Ill. (see www.pbclinear.com/Pages/Linear-Components, the disclosures of which are incorporated herein by reference). A linear rail50may be secured to the bottom of base20, and may have bearing carriages51,52,53, and54being slidable thereon, as seen inFIG. 1. Depending upon the linear rail selected, and the method utilized for attachment to the housing base20, it is possible for the second leg32of the “L”-shaped mounting member30to attach directly to the bearing carriages51and52, with the second leg42of the “L”-shaped mounting member40attaching directly to the bearing carriages53and54.

Alternatively, and as may be seen inFIG. 8, a split linear rail50A and50B may be used, with pairs of bearing carriages51A, SIB,52A,52B,53A,53B,54A, and54B being slidable upon the rail pair50A/50B, and with carriages51A,51B,52A, and52B being secured to a mounting block61, and with carriages53A,53B,54A, and54B being secured to a mounting block62. As seen inFIG. 1, the opening formed between the split rails50A/50B and bearing carriage pairs may serve to permit attachment of the second leg32of the first “L”-shaped member30to mounting block61, and permit attachment of the second leg42of the second “L”-shaped member40to mounting block62. (Note—attachment of any of the housing components or other parts described herein may be accomplished using a suitable adhesive or any mechanical fasteners know in the art to be appropriate for the materials used, which may be wood, metal, or plastic). With the length of the linear split rails50A/50B selected to span the slotted openings20A and20B in base20, the first mounting member30may thereby be slidable with respect to the first end of the housing, being proximate to the housing end wall21, within slotted opening20A. The second mounting member40may thereby be slidable with respect to the second end of the housing, being proximate to the housing end wall22, within slotted opening20B.

An advanced anvil12, which incorporates the features disclosed in co-pending application Ser. No. 12/925,652, may be secured to the mounting block61. In a preferred embodiment, an angled gusset assembly64may first be secured to the mounting block61, and then the anvil12may be secured to the gusset assembly64. To accommodate the build-up of tolerances and to generally permit adjustments to the precise static positioning of the anvil, the importance of which is discussed hereinafter, a base plate65may be located between the gusset assembly64and the anvil12, and leveling feet may be positioned between the base plate65and the anvil12.

An advanced sonotrode13, which incorporates features disclosed in co-pending application Ser. No. 12/925,652, may form part of a stack that also includes a booster14and a converter15. The stack may be secured to the mounting block62using upper and lower clamp blocks65U/65L that secure the booster, and upper and lower clamp blocks66U/66L that secure the converter. The upper clamp blocks65U and66U may each be fixedly secured to the mounting block62, and the lower clamp blocks65L and66L may each be releasably secured to the corresponding upper clamp blocks using set screws67, to releasably secure the stack to the mounting block62.

One embodiment of the leveling feet, base, and anvil is shown in an exploded view inFIG. 12. In the embodiment ofFIG. 12, leveling feet66A,66B,66C,66D,66E,66F, and66G are shown prior to being threadably engaged within corresponding threaded holes in the anvil12, after which the anvil and leveling feet may be secured to the base and to the gusset assembly64using screws68, as seen inFIG. 11andFIG. 3. The degree to which each of the leveling feet66A-66G are threadably engaged therein may be adjusted—inward and outward—in order to provide carefully controlled and adequate support across the length of the anvil13, so that its series of energy director grids, as described in co-pending application Ser. No. 12/925,652, may properly engage the corresponding series of energy director grids of the advanced sonotrode13. A contact sheet may be utilized between the energy director grids of the sonotrode and the anvil, during their engagement, which is discussed hereinafter, to determine if the engagement is proper, with adjustments to the leveling feet being made to achieve uniform contact therebetween.

With this arrangement ofFIG. 1, a first fluidic muscle16may have a first end16A being fixed to the second end wall22of the housing, and a second end16B of fluidic muscle16may be fixed to the first leg31of “L”-shaped mounting member30. A second fluidic muscle17may have a first end17A being fixed to the housing mid-wall26of the housing, and a second end17B of fluidic muscle17may be fixed to the first leg41of “L”-shaped mounting member40. The fluidic muscles16and17may preferably be attached as described to also be disposed in-line, relative to the linear rail50and to the anvil12and the stack with sonotrode13. This in-line arrangement creates an assembly that possesses a very narrow, though elongated shape, which facilitates installation of the retrofit kit10into a space constrained envelope currently occupied by the heat seal station of certain form-fill-seal machines (see generallyFIGS. 3 and 4, which illustrate installation of a second retrofit kit embodiment10A of the present invention onto such a machine).

With the retrofit kit10being assembled as described above, and with pneumatic/hydraulic tubes being appropriately installed to port pressure to the fluidic muscles16and17, pressurizing of the first and second fluidic muscles may cause translation of the first muscle mounting member30and translation of the second muscle mounting member40, with the translation being generally simultaneous and being relative to the linear rail, and with it causing convergence of the two mounting member so as to cause engagement of a surface of the anvil12with a surface of the sonotrode13. A controller may be used to sequence porting of pneumatic/hydraulic pressure to the fluidic muscles and corresponding depressurizing, with the pulsing of electric power to the stack to cause the mechanical vibrations that creates friction between the “work piece” materials (the sides of the open end of the pouch) to generate heat to melt the contact area therebetween. Depressurizing of the first and second fluidic muscles16and17may cause reverse-translation of the first and second muscle mounting members30and40relative to the linear rail pair50A/50B to cause disengagement of (or separation between) the engaging surface of the anvil12and the engaging surface of said sonotrode13, after an appropriate weld time has elapsed.

The translation of the two mounting members30and40need not be simultaneous, but it is important that the engaging surface of the anvil12and the engaging surface of the sonotrode13meet at a prescribed “mid-plane,” where the pouch is positioned. (Note that the respective engaging surfaces of the anvil12and sonotrode13may not be planar, such as when using the energy director grids of the Applicant's co-pending application Ser. No. 12/925,652, in which case the “mid-plane” may be construed to be found by generally using the plane formed at the most extreme portion of the plateau surfaces therein, or the plateau surface itself when it is formed to be planar). As seen inFIG. 7, a mechanical stop55may be used to institute a travel limiting set point so that when the fluidic muscles are activated, the anvil and sonotrode will suitably mesh in the middle. Typically the anvil side reaches the mid-plane first, since there is less mass to move, and it's travel will thereat be limited by contact with the mechanical stop55. The horn side will soon thereafter come into contact with the anvil in the middle, as set by the adjustable mechanical stop55. Without the adjustments provided by the mechanical stop55, any differential in reaching the pouch may otherwise serve to cause deflection of the pouch, resulting in a distorted weld line, and an aesthetically unappealing package. Having two different sized fluidic muscles16and17may require some additional adjustment to the arrangement to coordinate the arrival times of the anvil12and sonotrode13at the plane where the pouch is to be sealed. If the first and second fluidic muscles are the same size, certain efficiencies may be obtained.

A second embodiment10A of the retrofit kit of the current invention is shown mounted to a horizontal form-fill-seal machine inFIGS. 3 and 4. This installation of the kit10A is shown enlarged inFIG. 3A, and has its component parts shown in the exploded view ofFIG. 7. The kit10A may make use of two identical fluidic muscles18and19, and may therefore be capable of simultaneous and equal translation amounts for both the anvil12and sonotrode13, largely eliminating the need for adjustments due to different travel distances or times. InFIG. 3, it may be seen that the engaging surface of the anvil12and the corresponding engaging surface of the sonotrode13may each be located, prior to pressurization of the fluidic muscles and the associated translation, approximately 0.5 inches away from the mid-plane at which the pouch to be sealed may ideally be positioned. Utilizing the same fluidic muscle19for translation of the sonotrode13on the slidably mounted block62, as the fluidic muscle18for translation of the anvil12on the slidably mounted block61, may also result in equal speeds of translation.

Inline positioning of the same fluidic muscles18/19may be accomplished, as seen inFIGS. 3A and 7for this second embodiment, by providing a clearance hole36in the first mounting member35to permit sliding of the first mounting member relative to the fluidic muscle19without any contact occurring therebetween, and by providing a clearance hole46in the second mounting member45to permit sliding of the second mounting member45relative to the fluidic muscle18without any contact occurring therebetween. Many other aspects of retrofit kit10A may otherwise be similarly constructed to retrofit kit10. The first end18A of the fluidic muscle18may be secured to the housing, albeit by passing through the oversized orifice46in the second mounting member45, and possibly being with the use of an extended end fitting18Ei on the fluidic muscle, with the fitting having a threaded portion thereon to which a nut95may torqued to secure it to the housing end wall22. The second end18B of the fluidic muscle18may also have an extended end fitting18Eii with a threaded portion thereon to which a nut95may be torqued to secure it to the first mounting member35. Also, the first end19A of the second fluidic muscle19may be secured to the housing, albeit by passing through an oversized orifice36in said first mounting member35, and possibly being with the use of extended end fitting19Ei on the fluidic muscle, with the fitting having a threaded portion thereon to which a nut95may torqued to secure it to the housing end wall21. The second end19B of the fluidic muscle19may also have an extended end fitting19Eii with a threaded portion thereon to which a nut95may be torqued to secure it to the first mounting member45.

Retrofit of the advanced technology ultrasonic anvil and sonotrode onto existing form-fill-seal machines may require the removal of one or more heat sealing stations and any associated support brackets originally used to secure the heat station to a frame of the machine. The retrofit kit10or kit10A may be supplied for installation thereon. Because of differences in the frame and other features of certain machines produced by various manufacturers, a horizontal machine spacer assembly80(FIGS. 3,3A,6, and7) may be needed to properly position the kit so that the anvil and sonotrode are both properly displaced on opposite sides of the theoretical pouch mid-plane, as the pouches advance along the conveyor. Also, for a rotary form-fill-seal machine, such as the one shown inFIGS. 8 and 9, proper installation of the kit may also require support of the outward radially located end of the kit, through the use of a rotary machine column assembly90.

Each of the kits, as well as the horizontal machine spacer assembly80or the rotary machine column assembly90, may require drilling of mounting holes into the frame of the machine that is to be retrofitted. As seen inFIG. 5, these holes may be located in one of the housing end walls21122as pilot holes, which may then be used as a template for drilling common full size holes in both the kit and the machine's frame. Thereafter, the kit may be secured to the frame of either a horizontal or a rotary form-fill-seal machine using any suitable fastening means known to one skilled in the art, including, but not limited to, nuts, lock washers, and bolts.

A third embodiment disclosed herein may be the pedestal-mounted ultrasonic welding device assembly200that is shown in the three views ofFIGS. 13-15, and in the perspective view ofFIG. 16. The pedestal-mounted ultrasonic welding device assembly200may include the welding device201(FIG. 16A), the pedestal202(FIG. 16B), and cradle brackets203to connect to and support the welding device from the pedestal. The ultrasonic welding device201may generally be constructed similar to the hereinabove disclosed device for retrofit kit10or10A. However, welding device201may preferably be constructed to even further optimize its compactness, with a goal of readily permitting the unit to be utilized for replacement of the heat station or other sealing devices of an original equipment manufacturer (OEM), by meeting the envelope requirements of both the equipment previously placed in service and also the equipment that is being manufactured today.

Ultrasonic welding device201, unlike the hereinabove disclosed device for retrofit kit10or10A that used fluidic muscles, may instead utilize an off-the-shelf gripper—a pneumatic device that actuates the horn and anvil, to cause clamp-up upon the work pieces to be welded. The parallel gripper270, model DHPS manufactured by Festo, is shown inFIGS. 18A and 18B, and may be utilized herein (see, www.festo.com/cms/nl-be_be/9767.htm, and U.S. Pat. No. 6,199,848 to Bellandi, with the disclosures of each being incorporated herein by reference). As seen inFIGS. 18 and 20, the gripper270may be secured to the housing271, which may be a casting, and the gripper may be secured using suitable mechanical fasteners and may also include the use of mounting plate274. The anvil support member272—the equivalent of the corresponding mounting member discussed hereinabove—may be fixedly secured to bearing carriages251A,251B,252A, and252B, and may thereby be driven to slide relative to the linear rails250A/250B by its connection with one of the pistons of the gripper270. Similarly, the stack support member273, which supports the component parts of the stack—the sonotrode213, booster214, and converter215—may be fixedly secured to the bearing carriages253A,253B,254A, and254B, and may thereby be driven to slide relative to the linear rails250A/250B by its connection with the other piston of the gripper270. It should be noted that the anvil support member272and the stack support member273, each of which may be formed in a casting process for this embodiment, may each alternatively be configured to slidably mount directly to the linear rails250A/250B without requiring the use the separate bearing carriages (251A,251B,252A . . . ). In addition, a single central rail, as opposed to the pair of rails linear rails250A/250B, may also be successfully used, except that the use dual linear rails may offer added stability for movement of the advanced anvil and sonotrode.

FIG. 17shows three different versions of the pedestal mounted ultrasonic welding device of the present invention, including two versions—the one on the left-hand side (200Bi) and one on the right-hand side (200Bii)—which have the cradle brackets mounted to the exterior of the cover of the device, and ultrasonic welding device200being shown in the center of the figure, in which the cradle brackets203may instead mount to the housing271beneath the interior of the cover220. This arrangement for device200, along with other changes, results in an overall width of less than 200 mm for the device, as seen inFIG. 14, to thereby meet the space requirements of many OEMs, and which also permits removal of the cover220(FIG. 19A), without first requiring removal of the cradle brackets203. A removable access panel225may be releasably secured to cover220, as seen inFIGS. 19A and 19B, to permit quick access to flow controls and grease fittings, and may be used in conjunction with a nitrile food-grade gasket226to support wash-down of the device). A shallow height actuator in the pedestal203presently results in an overall height of the assembly of 679 mm (FIG. 13), while still permitting column height adjustments of 50 mm, and the present overall length of 540 mm provides for good clearance from the inner dial plate of more models of different OEM equipment (e.g., more clearance on the anvil side near the table dial).

The perspective view ofFIG. 19shows the advanced ultrasonic welding device201with the cover220removed to expose the open and close sensors245. The open and close sensors may provide input to a microprocessor, indicating the position of the sonotrode—being either distal from the anvil (open) prior to the beginning of a cycle, or engaging the anvil (closed). The close sensor allows for programming in a delay time if needed to build up proper forces for welding, and/or to also coordinate the timing of the vibrations to occur during the point at which the work pieces are engaged between the sonotrode and anvil. In addition, one or more pouch presence sensors may also be used, because cycling the device and applying ultrasonic energy without a work piece or work pieces being positioned between the horn and anvil can severely damage the equipment. Therefore, pouch presence sensors ensure that the ultrasonic horn and anvil never fire directly against each other.

It is fairly common for such ultrasonic welding machines to be cleaned in a wash-down environment that may include the use of caustics, which had in the past been accommodated by anodizing the structural components to increase their corrosion resistance. However, the oxide layer created by the anodizing process tends to wear off quickly. Therefore, many of the structural components of the ultrasonic welding device assembly200(the castings used for the first and sonotrode and anvil support members, etc.—seeFIG. 20) receive a food-grade ceramic reinforced Teflon® coating, which enables use of the device in a wash-down environment that includes caustics. The linear rails50A and50B of embodiments10and10A have been replaced on device200with a pair of stainless steel rods250A/250B and matching stainless steel bearing rails (250A,250B,251A, . . . ), to also better facilitate the exposure in the wash-down environment.

The advanced anvil212, the engagement surface of which may include the energy director grids described in co-pending application Ser. No. 12/925,652, may generally be reduced in overall height, as seen inFIG. 21. The height reduction accommodates the gripping of pouches, within the original equipment, at a position higher up on the pouch to nearly eliminate any “fold over” conditions (e.g., when a pouch is not guided properly into the weld station it can catch an edge and fold over and not be sealed properly or at all). The converter and booster are modified to be one contiguous assembly that will have an ingress Protection/International Protection rating of IP67 (6—generally indicating dust-tight, and 7 generally indicating durability for at least 30 minutes when immersed in one meter of water).

FIG. 21is an enlarged detail view of the anvil212, leveling feet266A/266D/266F, and mounting base plate265of the pedestal-mounted advanced ultrasonic welding device200. Adjustments using the leveling feet may be understood through an examination ofFIGS. 22A-22F.FIG. 22Ashows the leveling foot266F having been threadably received within an internally threaded hole in the anvil212. The other leveling feet (266A-266E and266G) may similarly be threadably received within corresponding threaded holes in the anvil212. The anvil212with leveling feet secured thereto may next be placed over the mounting base plate265to generally align the leveling feet with the corresponding holes in the base plate, as seen inFIG. 22B. A holding screw268may then be used to secure the anvil to the mounting base plate265at each of the leveling feet locations.

With the anvil212so installed upon the ultrasonic welding device201, as seen inFIG. 21, proper uniformity of the depth of engagement of the sonotrode213with the anvil212, to produce the narrow ultrasonic weld having improved durability and integrity, may next be assured through adjustments to the leveling feet. To ascertain what adjustments may be necessary, a pressure sensitive film may be positioned in the plane where the work pieces would normally be acted upon during the welding process, while a single stroke of the sonotrode and anvil may be manually indexed, to thereby make an impression upon the film. The film that may desirably be utilized is available from Sensor Products, Inc., in Madison, N.J. After mannually indexing the anvil and sonotrode, an examination of the film will reveal the resultant grid pattern impression from the engagement of the energy director grids of the sonotrode and anvil, which should be uniform in both the top to bottom (short) direction, as well as in the left to right (lengthwise) direction. If the impression is not uniform, the depth of engagement may be adjusted locally, by adjusting the nearest leveling foot. For example,FIG. 22Gshows the impression made on a piece of film, in which there generally a uniform pattern, except for a region in the bottom right corner, in which the was an insufficient amount of contact, resulting in little to no impression being made in that region. An adjustment for such a regional non-uniformity is shown inFIGS. 22C-22F. The holding screw268in the corner corresponding to the insufficient contact may be loosened, for example by being loosened one-quarter of a turn (FIGS. 22C-22D), then the leveling foot may be used to raise (or alternatively lower) the anvil locally by being rotated with the application of a wrench upon the flats of the hex portion of the leveling foot (FIGS. 22E-22F). In this case, the leveling foot is backed away from the anvil to cause greater engagement between the anvil and sonotrode at that position. The holding screw268may next be re-tightened; with the verification process repeated using another piece of pressure sensitive film, until optimum results have been obtained, such as the uniform pattern illustrated inFIG. 22H.

As seen inFIG. 21, two of the holding screws268may be loosened/tightened from the front side of the anvil, and, as seen inFIG. 22, three of the holding screws268may be loosened/tightened from the back side of the anvil—an arrangement that resulted from the size reduction in the anvil to meet the space requirements of certain OEM equipment. Also, adjustments to the leveling feet are more conveniently made by staggering the positioning of the leveling feet across the mounting plate, which nonetheless provides sufficient support for the anvil, while providing better wrench access to rotate the hex portion of the feet.

On the ultrasonic welding device201, a narrower jaw opening is facilitated by the addition of pouch guides235and236(seeFIGS. 23-24). The pouch guides help to assure clearance of the pouches with the anvil/sonotrode during the relative motion therebetween. The anvil pouch guide235may be mounted directly to the anvil support member, while pouch guide236, which is configured to assure clearance of the film with the sonotrode212, may be fixedly mounted to the cradle bracket203. Using pouch guides235and236permits use of the narrower jaw opening, which serves to reduce the stroke of the sonotrode down to a minimum, which improves the speed at which the ultrasonic welding device201may operate. If the “jaws” of the device (engagement surfaces of the sonotrode and anvil) were opened wider, it would consequently take longer to close them for each sealing cycle.

A further improvement may also be made to the advanced anvil and sonotrode that are found in our co-pending application Ser. No. 12/925,652, the details of which are briefly reiterated here in order to more aptly describe the improvement thereto.FIGS. 25-27show three views of the improved sonotrode213, which may have an engagement surface278. As with the invention of the co-pending application, the sonotrode and the corresponding anvil herein may each also comprise a plurality of specially constructed energy directors279that may be arranged into a coordinated three-dimensional grid pattern, being coordinated between the sonotrode and anvil. The coordinated pattern may selectively increase the total surface area of the anvil that may be capable of distributing vibrations in a three-dimensional pattern of vibration-transmissive contact with the sonotrode, and which may also cause a discrete amount of deformation of the work pieces during the sonotrode-to-anvil engagement (FIG. 31). The deformation may preferably be limited to a small amount, and therefore be limited to maintaining the work pieces within the elastic range of the material. The increase in surface area of contact may depend upon the width of the plateau surfaces used, as described hereinafter. The three-dimensional contact pattern may be understood by an examination ofFIG. 28andFIG. 29.

The energy directors279of the sonotrode213may be regularly spaced apart from each other, as seen inFIG. 28. The energy directors279may preferably be spaced apart in a first direction that may parallel the weld line, and may similarly be spaced apart in a second direction being generally away from, or orthogonal to, the weld line, to form the grid pattern. Each of the energy directors279may comprise a plateau surface280that may be formed by a first angled side surface281, a second angled side surface282, a third angled side surface283, and a fourth angled side surface284, where the plateau surfaces280may each comprise a rectangular-shape that may be oriented at a 45 degree angle to the weld line. At the meeting of adjacent side surfaces281and282of the adjacent plateau surfaces280, there may be a valley bottom or trough287that may be oriented at a minus 45 degree angle with respect to the weld line, and at the meeting of the adjacent side surfaces283and284of adjacent plateau surface280, there may be a trough288that may be oriented at a plus 45 degree angle with respect to the weld line. The trough may be a line formed by the intersection of two planar surface, or it may be a radiused surface.

The rectangular-shaped plateau surface280lends itself very well to a repetitive pattern of engagement between the sonotrode and anvil, described hereinafter; however, other geometric plateau shapes may also be utilized, which would naturally alter the side-surface arrangement. Also, the rectangular-shaped plateau surfaces80may each be generally flat, although contoured plateau surfaces80A may alternatively be utilized.

As seen inFIG. 29, the energy directors279of the sonotrode213may have a span therebetween of 0.020 inches, and may have a depth of 0.006 inches from the plateau surface280to the troughs287/288, which may be formed using a conventional machining process or through the use of a wire EDM process. The angled side surfaces may each be at an angle θ, which may be different for various configurations, but in the first embodiment, angled side surfaces281,282,283, and284may be oriented such that the angle θ is a 45 degree angle, which, when resolved geometrically, would result in the width of the plateau surfaces280being 0.008 inches. Since the dimensions of the energy directors279may not necessarily be very large with respect to the material thicknesses being welded, the amount of deformation, discussed earlier, may similarly not be very large, and thus does not generally pose an issue as to tearing of the material of the work pieces.

The anvil may have corresponding energy directors, and may similarly include plateau surfaces, as well as the associated side surfaces. The improved sonotrode213and anvil212may be constructed to have engagement therebetween of energy directors which include a greater surface area of contact created by the corresponding side surfaces, than the traditional flat surfaced sonotrode contacting a flat surfaced anvil. This increased surface area of contact, which may be seen inFIG. 30just prior to engagement of the sonotrode and the anvil with the work pieces, and inFIG. 31by the direct contact and the anvil with the sonotrode without any work pieces therebetween, may cause minor deformation immediately prior to application of ultrasonic vibrations, which results in a more durable seal from such ultrasonic welding of two work pieces. Also, the plateau surfaces may preferably transition at the boundaries of the sonotrode and anvil, as seen inFIG. 30A. The transitions may include a corner radius preferably being in the range of 0.030-0.046 inches. Furthermore, the plateau surfaces may also taper down toward those radiused corners, beginning at an offset of approximately 0.062 from the edge, and having an angle of taper preferably in the range of one to two degrees.

The engagement surfaces of these energy director grids for both the sonotrode and anvil are preferably coated with a food-grade ceramic reinforced Teflon® coating, to prevent sticking of the thin plastic film thereto, as a result of the heating/melting that occurs during the ultrasonic welding process, particularly where a fold over condition has occurred. Since those values for the configuration of the energy directors represent final dimensions after coating, the machined dimensions of those parts are correspondingly smaller to account for the thickness of the coating.

The alignment of the anvil and sonotrode, being advantageous for thinner work pieces to dramatically improve weld durability, may utilize such alignment between the energy director grids where the side surfaces of the sonotrode plateaus interlock with the side surfaces of the anvil plateaus (FIG. 31) in a repeating 3-dimensional pattern, which may cause minor elastic deformation of the work pieces prior to or during ultrasonic welding. When the work pieces are inserted between the sonotrode and anvil (FIG. 30), and pressure is applied between the anvil and sonotrode, along with suitable vibrations provided by the design of the particular sonotrode, a three-dimensional weld results. The three-dimensional weld exhibits significantly improved durability over that of conventional ultrasonic welds. Depending on the length of the plateau surface utilized on both the anvil and sonotrode, the surface area of contact may be increased considerably. Where a relatively small plateau surface is used, perhaps even somewhat smaller than the one illustrated inFIGS. 29and31, the surface area of contact may be significantly increased, and may therefore serve to further reduce the weld times and may also serve to further improve the weld quality/durability.

An improvement to the above described sonotrode and anvil with grids of energy directors thereon, is shown initially within by the engagement surface of the sonotrode that is seen inFIG. 27. The grid pattern may be selectively interrupted to locally produce a smooth weld that resembles the logo of the company marketing the particular product to be sealed within the pouch. It should be noted that the use herein of the term “logo” is meant to convey any graphic representation or symbol of a company's name, product, trademark, abbreviation, etc., or any other design or information for which it is desirable to have visibly highlighted.

FIG. 32shows an enlarged detail view of the logo of FIG.27—the name “rinco” and an adjacent symbol. The “rinco” logo may be produced using one of several different approaches. In a first approach, the anvil may have energy directors distributed across its entire engagement surface, without interruption, while the sonotrode may have a plurality of logo surfaces machined into the energy directors of its engagement surface to thereby spell out “rinco.” Instead, the logo surfaces, which may preferably be flat, may be machined into the engagement surface of the sonotrode, while the anvil may have energy directors distributed across its entire engagement surface. With either of these approaches, the weld of increased durability produced by engagement between the energy directors may result in a textured seal surface on both sides of the joined work pieces, except for the region of the work pieces that were proximate to the logo surfaces, where the thin film may still be smooth on each of the two sides. However, with either of these two approaches, despite the fact that the work pieces are not engaged locally within the region that results in the spelling of the logo “rinco” and are generally not sealed thereat, there may sometimes nonetheless be some transmission of vibrations and a correspondingly small amount of melting therein to produce within the logo what is termed “witness marks,” These marks may be eliminated by machining the logo surfaces down to a sufficient depth on both the sonotrode and the anvil, so that no contact occurs with the work pieces fro either side, so no melting occurs in the region of the logo, and consequently no witness marks appear. Since no sealing of any significance occurs in the pouch in the region of the logo, the energy directors should generally extend at least 2-3 rum beyond the periphery of the logo, to produce a welded joining of the thin film work pieces having sufficient integrity to prevent leakage.

Another alternative approach includes deliberately sealing of the work pieces by the logo surfaces. The section cut taken through the letter “r” of that name “rinco” inFIG. 32, is used to illustrate the logo surface depth, and changes to the corresponding grids of energy directors, as seen inFIG. 33. Both the sonotrode213and the anvil212may have a corresponding logo surface-213Lr and212Lr—that may be used to produce the letter “r,” where each logo surface may transition into adjacent energy directors used to produce the more durable weld. In one embodiment of these sonotrode and anvil logo surfaces that produce sealing, they may be configured, as seen inFIG. 33, to be nominally positioned so that when the sonotrode and the anvil are in direct contact (no work pieces between them), they are positioned between both the plateau surfaces of the sonotrode and the plateau surfaces of the anvil. The distance between the flat logo surfaces of the sonotrode and the flat logo surfaces of the anvil, as seen inFIG. 33, may be such that when the sonotrode engages the anvil, they each make minimal contact with the thin film work pieces to cause melting and sealing that forms the “rinco” outline. This may result, when used in the welding process for the joining of two work pieces, in the logo “rinco” being inset within the peaks of the textured seal surface. In a second embodiment of this alternative approach, the logo surfaces of the sonotrode and the logo surfaces of the anvil may be configured, as seen inFIG. 34, to be nominally positioned so that when the sonotrode213′ and the anvil212′ are in direct contact, they are beyond both the plateau surfaces of the sonotrode and the plateau surfaces of the anvil. So when the sonotrode engages the anvil during the welding process, the logo surfaces on the sonotrode213minimally deform the work pieces and push them into contact with the logo surfaces of the horn212, thereby causing melting and sealing to form the “rinco” outline. However, in this embodiment, it may result in the “rinco” logo being raised slightly above the peaks on one side of the textured seal surface that was formed by the energy directors.

The examples and descriptions provided merely illustrate a preferred embodiment of the present invention. Those skilled in the art and having the benefit of the present disclosure will appreciate that further embodiments may be implemented with various changes within the scope of the present invention. Other modifications, substitutions, omissions and changes may be made in the design, size, materials used or proportions, operating conditions, assembly sequence, or arrangement or positioning of elements and members of the preferred embodiment without departing from the spirit of this invention.