Retrofit of a Form-Fill-Seal Machine Heat Station with an Advanced Ultrasonic Welding Kit

Abstract

Advanced ultrasonic welding components of Applicant's U.S. Pat. No. 8,376,016 are readily incorporated into new form-fill-seal machines, but owners of existing machines utilizing heat-seal stations were unsuccessful at swapping the sealing packages. Retrofit kits to a replace heat sealing stations with an advanced ultrasonic sonotrode and anvil comprise: a housing; a linear rail fixed thereto; first and second bearing carriages being slidable upon the rail; and first and second fluidic muscles. Each of the fluidic muscles is mounted with a first end fixed to a respective housing wall, and a second end fixed to a respective bearing carriage, permitting actuation of each carriage through pressurization/depressurization of the muscles. The advanced anvil and sonotrode may be secured to respective carriages. In-line arrangements of anvil/sonotrode, bearing carriages, the first fluidic and second fluidic muscles provides a narrow profile, permitting side-by-side kit installations for retrofits accomplishing duplex sealing on a horizontal machine.

Claims

1. An ultrasonic scaling station, for use in supporting an anvil and sonotrode of an ultrasonic welding stack of a form-fill-seal machine, said ultrasonic sealing station comprising: a housing; a linear rail with a portion of said linear rail fixedly secured to a portion of said housing; a first bearing carriage slidably received upon said linear rail; a second bearing carriage slidably received upon said linear rail; a first fluidic muscle; a second fluidic muscle; wherein said first fluidic muscle is configured with a first end secured to a portion of said housing and with a second end secured to said first bearing carriage; said first bearing carriage configured to fixedly secure an anvil thereto; wherein said second fluidic muscle is configured with a first end secured to a portion of said housing and with a second end secured to said second bearing carriage; said second bearing carriage configured to fixedly secure a sonotrode thereto; wherein said first and second fluidic muscles are configured to be pressurized to cause convergent translation of said first and second bearing carriages, said convergent translation being calibrated, to cause engagement between a surface of the anvil and a surface of the sonotrode.

2. The ultrasonic sealing station according to claim 1 wherein said first and second fluidic muscles are configured to be depressurized to cause reverse-translation and divergence of said first and second bearing carriages, to cause disengagement of the surface of the anvil from the surface of the sonotrode.

3. The ultrasonic sealing station according to claim 2 wherein said first fluidic muscle and said second fluidic muscle are substantially the same size, and are configured to provide a substantially equal amount of said convergent translation for said first bearing carriage and for said second bearing carriage.

4. The ultrasonic sealing station according to claim 3 wherein said first and second fluidic muscles are secured to said housing to form a narrow profile, with said first and second fluidic muscles disposed in-line with respect to said linear rail.

5. A method of retrofitting one or more heat sealing elements of a form-fill-seal machine, with a sonotrode and anvil, said method comprising: removal of said one or more heat sealing elements and associated support brackets: providing a retrofit kit, said retrofit kit comprising: a housing; a linear rail with a portion fixedly secured to a portion of said housing; a first bearing carriage slidably received upon said linear rail; a second bearing carriage slidably received upon said lineal rail; a first fluidic muscle; a second fluidic muscle; a first mounting member fixedly secured to said first bearing carriage to be slidable relative to said housing; said first fluidic muscle configured with a first end secured to a portion of said housing and with a second end secured to said first mounting member; said first mounting member configured to fixedly secure an anvil thereto; a second mounting member fixedly secured to said second bearing carriage to be slidable relative to said housing; said second fluidic muscle configured with a first end secured to a portion of said housing and with a second end secured to said second mounting member; said second mounting member configured to fixedly secure a sonotrode thereto; an anvil secured to said first mounting member; sonotrode secured to said second mounting member; wherein said first and second fluidic muscles are configured to be pressurized to cause corresponding translation of said first and second mounting members relative to said housing, to cause convergent translation of said first and second mounting members; drilling mounting holes in a frame of the machine; and installing said retrofit kit in the frame of the machine by securing said housing of said retrofit kit to the frame using a fastening means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a perspective view of a first embodiment of the main components of an advanced ultrasonic welding retrofit kit of the current invention, with a housing side panel removed to expose the fluid mechanical muscles therein.

[0017] FIG. 2 is a perspective view of the retrofit kit of FIG. 1, with the housing panel shown installed to enclose the fluid mechanical muscles.

[0018] FIG. 3 is an enlarged side view of a second embodiment of the retrofit kit of the current invention.

[0019] FIG. 3A is a further enlarged view of the retrofit kit of FIG. 3.

[0020] FIG. 4 is an end view of the retrofit kit of FIG. 3.

[0021] FIG. 5 is a perspective view of the retrofit kit of FIG. 3.

[0022] FIG. 6 is the perspective vi the retrofit kit of FIG. 5, being reduced in size and shown with an optional horizontal machine spacer, and with an optional rotary machine column assembly that may be configured with a fixed static height, or an adjustable height in the vertical direction.

[0023] FIG. 7 is an exploded view of the parts comprising the retrofit kit, as seen in FIG. 6.

[0024] FIG. 8 is a front view of a rotary form-fill-seal machine capable of being retrofitted with the advanced ultrasonic welding retrofit kit of FIG. 6.

[0025] FIG. 9 is a top view of the rotary form-fill-seal machine of FIG. 8.

[0026] FIG. 10A is a side view of a prior art ultrasonic welding machine.

[0027] FIG. 10B is a front view of the prior art ultrasonic welding machine of FIG. 10A.

[0028] FIG. 11 is a detail view of an anvil that is usable with the present invention, along with leveling feet and a mounting base that is securable to the housing herein.

[0029] FIG. 12 is an exploded view of the anvil, leveling feet, and base of FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

[0030] 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, was 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 as 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.

[0031] FIG. 1 shows a perspective view of a first embodiment of the retrofit kit 10 of the present invention, which elegantly overcame these obstacles, being shown with a housing side panel 23 removed to expose the actuation portion of the invention.

[0032] 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.

[0033] 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 Mt. Prospect, Ill. (see www.festo.com).

[0034] Fluidic muscles are commonly utilized in pairsone 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.

[0035] In the simplest possible embodiment, a single fluidic muscle may be used to replicate the linear motion provided by the press 190 in a typical prior art ultrasonic welding machine 100, represented in FIGS. 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.

[0036] A first embodiment of the present invention is shown by the retrofit kit 10 in FIG. 1 (with a side panel 23 of the housing removed), and is also shown in FIG. 2. The retrofit kit 10, 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 base 20, a first end wall 21, a second end wall 22, a first side wall 23, and a second side wail 24. The housing may also comprise a mid-wall 26. Many of these components are common to a later discussed embodiment, for which an exploded view is shown in FIG. 7, so reference thereto may be advantageous. The housing side panels 23 and 24 may be used to enclose and protect the fluidic muscles, along with the base 20 and end walls 21 and 22, and in addition, an optional cover (not shown) may be used for those reasons as well. Also, side panels 23 and 24 may serve to add structural rigidity to the housing; however the panels 23 and 24 are not required for supporting the functionality of the mechanism, as will be seen hereinafter.

[0037] The base 20 may have a first opening 20A and a second opening 20B, both of which may be slotted openings. A first mounting member 30 may have a portion being disposed part-way through the first opening 20A in base 20. In one embodiment, first mounting member 30 may preferably be L-shaped, and may have one leg 31 of the L protruding up through the opening 20A in base 20, and the other leg 32 allay be disposed so as to generally parallel the base 20 of the housing. The first mounting member 30 may therefore be slidable within the slotted opening 20A of the base 20 of the housing. A second mounting member 40 may be similarly constructed with first and second legs 41 and 42, and be correspondingly disposed so as to be slidable within the second opening 20B in the base. The ends of the second legs 32 and 42 of the L-shaped mounting members may face each other within the kit assembly.

[0038] The second legs 32 and 42 of the L-shaped mounting members 30 and 40 may 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 rail 50 may be secured to the bottom of base 20, and may have bearing carriages 51, 52, 53, and 54 being slidable thereon, as seen in FIG. 1. Depending upon the linear rail selected, and the method utilized for attachment to the housing base 20, it is possible for the second leg 32 of the L-shaped mounting member 30 to attach directly to the bearing carriages 51 and 52, with the second leg 42 of the L-shaped mounting member 40 attaching directly to the bearing carriages 53 and 54.

[0039] Alternatively, and as may be seen in FIG. 8, a split linear rail 50A and 50B may be used, with pairs of bear cart 51A, 51B, 52A 52B, 53A, 53B, 54A, and 54B being slidable upon the rail pair 50A/50B, and with carriages 51A, 52B, 52A, and 52B being secured to a mounting block 61, and with carriages 53A, 53B, 54A, and 54B being secured to a mounting block 62. As seen in FIG. 1, the opening formed between the split rails 50A/50B and bearing carriage pairs may serve to permit attachment of the second leg 32 of the first L-shaped member 30 to mounting block 61, and permit attachment of the second leg 42 of the second L-shaped member 40 to mounting block 62. (Noteattachment 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 the linear split rails 50A/50B selected to span the slotted openings 20A and 20B in base 20, the first mounting member 30 may thereby be slidable with respect to the first end of the housing, being proximate to the housing end wall 21, within slotted opening 20A. The second mounting member 40 may thereby be slidable with respect to the second end of the housing, being proximate to the housing end wall 22, within slotted opening 20B.

[0040] An advanced anvil 12, which incorporates the features disclosed in co-pending application Ser. No. 12/925,652, may be secured to the mounting block 61. In a preferred embodiment, an angled gusset assembly 64 may first be secured to the mounting block 61, and then the anvil 12 may be secured to the gusset assembly 64. 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 plate 65 may be located between the gusset assembly 64 and the anvil 12, and leveling feet may be positioned between the base plate 65 and the anvil 12.

[0041] An advanced sonotrode 13, which incorporates features disclosed in co-pending application Ser. No. 12/925,652, may form part of a stack that also includes a booster 14 and a converter 15. The stack may be secured to the mounting block 62 using upper and lower clamp blocks 65U/65L that secure the booster, and upper and lower clamp blocks 66U/66L that secure the converter. The upper clamp blocks 65U and 66U may each be fixedly secured to the mounting block 62, and the lower clamp blocks 65L and 66L may each be releasably secured to the corresponding upper clamp blocks using set screws 67, to releasably secure the stack to the mounting block 62.

[0042] One embodiment of the leveling feet, base, and anvil is shown in an exploded view in FIG. 12. In the embodiment of FIG. 12, leveling feet 66A, 66B, 66C, 66D, 66E, 66F, and 66G are shown prior to being threadably engaged within corresponding threaded holes in the anvil 12, after which the anvil and mounting feet may be secured to the base and to the gusset assembly 64 using screws 68, as seen in FIG. 11 and FIG. 3. The degree to which each of the mounting feet 66A-66G are threadably engaged therein may be adjustedinward and outwardin order to provide carefully controlled and adequate support across the length of the anvil 13, 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 sonotrode 13. 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.

[0043] With this arrangement of FIG. 1, a first fluidic muscle 16 may have a first end 16A being fixed to the second end wall 22 of the housing, and a second end 16B of fluidic muscle 16 may be fixed to the first leg 31 of L-shaped mounting member 30. A second fluidic muscle 17 may have a first end 17A being fixed to the housing mid-wall 26 of the housing, and a second end 17B of fluidic muscle 17 may be fixed to the first leg 41 of L-shaped mounting member 40. The fluidic muscles 16 and 17 may preferably be attached as described to also be disposed in-line, relative to the linear rail 50 and to the anvil 12 and the stack with sonotrode 13. This in-line arrangement creates an assembly that possesses a very narrow, though elongated shape, which facilitates installation of the retrofit kit 10 into a space constrained envelope currently occupied by the heat seal station of certain form-fill-seal machines (see generally FIGS. 3 and 4, which illustrate installation of a second retrofit kit embodiment 10A of the present invention onto such a machine).

[0044] With the retrofit kit 10 being assembled as described above, and with pneumatic/hydraulic tubes being appropriately installed to port pressure to the fluidic muscles 16 and 17, pressurizing of the first and second fluidic muscles may cause translation of the first muscle mounting member 30 and translation of the second muscle mounting member 40, 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 anvil 12 with a surface of the sonotrode 13. 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 muscles 16 and 17 may cause reverse-translation of the first and second muscle mounting members 30 and 40 relative to the linear rail pair 50A/50B to cause disengagement of (or separation between) the engaging surface of the anvil 12 and the engaging surface of said sonotrode 13, after an appropriate weld time has elapsed.

[0045] The translation of the two mounting members 30 and 40 need not be simultaneous, but it is important that the engaging surface of the anvil 12 and the engaging surface of the sonotrode 13 meet at a prescribed mid-plane, where the pouch is positioned. As seen in FIG. 7, a mechanical stop 55 may 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 stop 55. The horn side will thereafter come into contact with the anvil in the middle, as set by the adjustable mechanical stop 55. Without the adjustments provided by the mechanical stop 55, 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 muscles 16 and 17 may require some additional adjustment to the arrangement to coordinate the arrival times of the anvil 12 and sonotrode 13 at 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.

[0046] A second embodiment 10A of the retrofit kit of the current invention is shown mounted to a horizontal form-fill-seal machine in FIGS. 3 and 4. This installation of the kit 10A is shown enlarged in FIG. 3A, and has its component parts shown in the exploded view of FIG. 7. The kit 10A may make use of two identical fluidic muscles 18 and 19, and may therefore be capable of simultaneous and equal translation amounts for both the anvil 12 and sonotrode 13, largely eliminating the need for adjustments due to different travel distances or times. In FIG. 3, it may be seen that the engaging surface of the anvil 12 and the corresponding engaging surface of the sonotrode 13 may 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 muscle 19 for translation of the sonotrode 13 on the slidably mounted block 62, as the fluidic muscle 18 for translation of the anvil 12 on the slidably mounted block 61, may also result in equal speeds of translation.

[0047] Inline positioning of the same fluidic muscles 18/19 may be accomplished, as seen in FIGS. 3A and 7 for this second embodiment, by providing a clearance hole 36 in the first mounting member 35 to permit sliding of the first mounting member relative to the fluidic muscle 19 without any contact occurring therebetween, and by providing a clearance hole 46 in the second mounting member 45 to permit sliding of the second mounting member 45 relative to the fluidic muscle 18 without any contact occurring therebetween. Many other aspects of retrofit kit 10A may otherwise be similarly constructed to retrofit kit 10. The first end 18A of the fluidic muscle 18 may be secured to the housing, albeit by passing through the oversized orifice 46 in the second mounting member 45, and possibly being with the use of an extended end fitting 18Ei on the fluidic muscle, with the fitting having a threaded portion thereon to which a nut 95 may torqued to secure it to the housing end wall 22. The second end 18B of the fluidic muscle 18 may also have an extended end fitting 18Eii with a threaded portion thereon to which a nut 95 may be torqued to secure it to the first mounting member 35. Also, the first end 19A of the second fluidic muscle 19 may be secured to the housing, albeit by passing through an oversized orifice 36 in said first mounting member 35, and possibly being with the use of extended end fitting 19Ei on the fluidic muscle, with the fitting having a threaded portion thereon to which a nut 95 may torqued to secure it to the housing end wall 21. The second end 19B of the fluidic muscle 19 may also have an extended end fitting 19Eii with a threaded portion thereon to which a nut 95 may be torqued to secure it to the first mounting member 45.

[0048] 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 kit 10 or kit 10A 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 assembly 80 (FIGS. 3, 3A, 6, and 7) 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 in FIGS. 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 assembly 90.

[0049] Each of the kits, as well as the horizontal machine spacer assembly 80 or the rotary machine column assembly 90, may require drilling of mounting holes into the frame of the machine that is to be retrofitted. As seen in FIG. 5, these holes may be located in one of the housing end walls 21/22 as 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.

[0050] 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.