Method and apparatus for forming slider end stops on zipper

• US 20040172802A1
• Filed: 03/19/2004
• Published: 09/09/2004
• Est. Priority Date: 05/17/2002
• Status: Active Grant

• Current Assignee: Donald L. Crevier
• Original Assignee: Donald L. Crevier
• Inventors: Crevier, Donald L.
• Granted Patent: US 6,968,604 B2
• Time in Patent Office: Days
• US Class Current: 29/408
• CPC Class Codes: B29C 2793/009 after shaping
• CPC Class Codes: B29C 65/08 using ultrasonic vibrations non-plastics element to plastics elements B29C65/645
• CPC Class Codes: B29C 65/18 using heated tools
• CPC Class Codes: B29C 65/72 by combined operations or combined techniques, e.g. welding and stitching
• CPC Class Codes: B29C 66/0242 Heating, or preheating, e.g. drying B29C66/3464 takes precedence
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/1222 comprising at least a lapped joint-segment
• CPC Class Codes: B29C 66/1224 comprising at least a butt joint-segment
• CPC Class Codes: B29C 66/306 Applying a mark during joining
• CPC Class Codes: B29C 66/326 Shaping the burr, e.g. by the joining tool
• CPC Class Codes: B29C 66/3452 Making complete joints by combining partial joints
• CPC Class Codes: B29C 66/348 Avoiding melting or weakening of the zone directly next to the joint area, e.g. by cooling
• CPC Class Codes: B29C 66/4312 for making flat seams in tubular or hollow articles, e.g. transversal seams
• CPC Class Codes: B29C 66/4322 by joining a single sheet to itself B29C66/4332 takes precedence
• CPC Class Codes: B29C 66/474 said single elements being substantially non-flat
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/81425 being stepped, e.g. comprising a shoulder
• CPC Class Codes: B29C 66/81431 comprising a single cavity, e.g. a groove
• CPC Class Codes: B29C 66/81433 being toothed, i.e. comprising several teeth or pins comprising a single tooth B29C66/81429, or being patterned
• CPC Class Codes: B29C 66/8322 : Joining or pressing tools reciprocating along one axis
• CPC Class Codes: B29K 2023/06 : PE, i.e. polyethylene
• CPC Class Codes: B29K 2023/0625 : LLDPE, i.e. linear low density polyethylene
• CPC Class Codes: B29K 2023/0633 : LDPE, i.e. low density polyethylene
• CPC Class Codes: B29K 2023/065 : HDPE, i.e. high density polyethylene
• CPC Class Codes: B29K 2023/12 : PP, i.e. polypropylene
• CPC Class Codes: B29K 2025/06 : PS, i.e. polystyrene
• CPC Class Codes: B29K 2027/06 : PVC, i.e. polyvinylchloride
• CPC Class Codes: B29K 2027/08 : PVDC, i.e. polyvinylidene chloride
• CPC Class Codes: B29K 2055/02 : ABS polymers, i.e. acrylonitrile-butadiene-styrene polymers
• CPC Class Codes: B29K 2059/00 : Use of polyacetals , e.g. POM, i.e. polyoxymethylene or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2061/00 : Use of condensation polymers of aldehydes or ketones or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2067/006 : PBT, i.e. polybutylene terephthalate
• CPC Class Codes: B29K 2069/00 : Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2077/00 : Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• CPC Class Codes: B29L 2005/00 : Elements of slide fasteners
• CPC Class Codes: B29L 2031/7129 : open
• CPC Class Codes: B31B 70/8131 : Making bags having interengaging closure elements
• CPC Class Codes: B65D 33/259 : End stops
• CPC Class Codes: Y10T 156/1343 : Cutting indefinite length web after assembly with discrete article
• CPC Class Codes: Y10T 29/49782 : of a slide fastener
• CPC Class Codes: Y10T 29/49785 : of interlocking element
• CPC Class Codes: Y10T 29/5101 : Slide fastener or slide fastener element
• CPC Class Codes: Y10T 29/53291 : Slide fastener
• CPC Class Codes: Y10T 29/53296 : Means to assemble stop onto stringer

Abstract

A method and a system for forming slider end stops on a zipper tape that comprises first and second interlockable zipper parts. The method comprises the following steps: (a) transmitting sufficient ultrasonic wave energy into first and second areas of the zipper tape to cause the first and second interlocked zipper parts to deform and fuse in the first and second areas, the first and second areas being separated by a gap; and (b) applying sufficient heat and pressure onto a third area of the zipper tape to cause the interlocked zipper parts to deform and fuse in the third area, at least part of the third area being located between the first and second areas in the gap. The first and second areas do not impinge upon the zipper rails. The third area does impinge upon the zipper rails. Thus the zipper rails are deformed in the third area, but not in adjacent areas located below and contiguous with the first and second areas. The zipper tape and packaging film are cut along a midline of the third area to sever each package from the continuous web.

Claims

1. An ultrasonic welding assembly comprising a horn and an anvil, wherein said horn comprises two prongs separated by a gap, each of said prongs comprising an end surface confronting said anvil, each of said end surfaces having at least a portion that is flat, said flat portions being generally coplanar.

2. The assembly as recited in claim 1, wherein each of said prongs further comprises a respective rail projecting forward of said respective end surface, said rail being shaped to serve as a dam for flowing thermoplastic material.

3. The assembly as recited in claim 2, wherein each of said prongs further comprises an energy director designed to direct ultrasonic energy into a mass of thermoplastic material and deflect flowing thermoplastic material of said mass toward said dam.

4. A method for forming slider end stops on a zipper tape that comprises first and second interlockable zipper parts, comprising the following steps:

(a) transmitting sufficient ultrasonic wave energy into first and second areas of said zipper tape to cause said first and second interlocked zipper parts to deform and fuse in said first and second areas, said first and second areas being separated by a gap; and

(b) applying sufficient heat and pressure onto a third area of said zipper tape to cause said interlocked zipper parts to deform and fuse in said third area, at least part of said third area being located between said first and second areas in said gap.

5. The method as recited in claim 4, further comprising the step of joining said zipper tape to opposing walls of packaging film material prior to said step (a).

6. The method as recited in claim 4, further comprising the step of mounting a slider to a portion of said zipper tape.

7. The method as recited in claim 5, further comprising the step of:

(c) applying sufficient heat and pressure onto a fourth area to form a seal that extends generally transverse to a lengthwise direction of said zipper tape, wherein said fourth area encompasses a portion of said zipper tape and opposed packaging film, said third and fourth areas are contiguous, and steps (b) and (c) are performed concurrently in one operation.

8. The method as recited in claim 4, wherein rails of said interlocked zipper parts overlap said third area but not said first and second areas, said rails being deformed in said third area.

9. The method as recited in claim 4, further comprising the step of cutting said zipper tape and said packaging film material along a line that passes through said third and fourth areas, but not said first and second areas.

10. The method as recited in claim 9, wherein said cutting line substantially bisects said third and fourth areas.

11. A system for forming slider end stops on a zipper tape that comprises first and second interlockable zipper parts, comprising:

an ultrasonic welding apparatus configured to transmit sufficient ultrasonic wave energy into first and second areas of said zipper tape to cause said first and second interlocked zipper parts to deform and fuse in said first and second areas, said first and second areas being separated by a gap; and

a conduction heat sealing apparatus configured to apply sufficient heat and pressure onto a third area of said zipper tape to cause said interlocked zipper parts to deform and fuse in said third area, at least part of said third area being located between said first and second areas in said gap.

12. The system as recited in claim 11, wherein said conduction heat sealing apparatus is also configured to apply sufficient heat and pressure onto a fourth area to form a seal that extends generally transverse to a lengthwise direction of said zipper tape, wherein said third and fourth areas are contiguous.

13. The system as recited in claim 12, further comprising means for cutting said zipper tape along a line that passes through said third and fourth areas, but not said first and second areas.

14. The system as recited in claim 13, wherein said cutting line substantially bisects said third and fourth areas.

15. The system as recited in claim 11, wherein said ultrasonic welding apparatus comprises a horn and an anvil, said horn comprising two prongs separated by a gap, each of said prongs comprising an end surface confronting said anvil, each of said end surfaces having at least a portion that is flat, said flat portions being generally coplanar.

16. The system as recited in claim 11, wherein said conduction heat sealing apparatus comprises a pair of mutually aligned and opposing sealing bars situated on opposing sides of said zipper tape.

17. The system as recited in claim 12, wherein a center of said ultrasonic welding apparatus and a center of said conduction heat sealing apparatus are separated by a distance equal to a width of a package.

18. The system as recited in claim 13, wherein a center of said ultrasonic welding apparatus, a center of said conduction heat sealing apparatus and said cutting means are spaced at increments equal to a width of a package.

19. A method for forming slider end stops, comprising the following steps:

advancing a web of packaging film material having a zipper tape joined thereto to a first station;

at said first station, ultrasonically stomping said zipper tape in first and second areas, said first and second areas being separated by a gap;

advancing said web by one package width in a lengthwise direction of said zipper tape so that said gap is in register with a second station; and

at said second station, conduction heat sealing in a third area that lies at least partly in said gap between said first and second areas and includes a contiguous strip that extends generally transverse to said lengthwise direction, a portion of said zipper tape within said third area being deformed and portions of said packaging film material within said third area being joined to form a seal having a predetermined width.

20. The method as recited in claim 19, further comprising the steps of:

advancing said web by one package width in said lengthwise direction so that said third area is in register with a cutting instrument at a third station; and

at said third station, cutting said zipper tape and said packaging film material along a straight line intersecting and dividing said third area to separate a package.

21. The method as recited in claim 19, further comprising the step of joining said zipper tape to opposing walls of said packaging film material prior to said first advancing step.

22. The method as recited in claim 19, further comprising the step of mounting a slider to a portion of said zipper tape.

23. The method as recited in claim 19, wherein said zipper comprises first and second rails, said rails being deformed during said conduction heat sealing step, but not during said ultrasonic stomping step.

24. An apparatus for forming packages having slider-operated zippers, comprising first and second stations having respective registration points spaced at a distance equal to one or more package widths along a machine direction, wherein:

said first station comprises an ultrasonic welding apparatus configured to ultrasonically stomp a zipper tape in first and second areas spaced in said machine direction, said first and second areas being separated by a gap; and

said second station comprises conduction heat sealing apparatus configured to heat seal packaging film material in a third area that lies at least partly in said gap between said first and second areas and includes a contiguous strip that extends generally transverse to said machine direction, a portion of said zipper tape within said third area being deformed and portions of said packaging film material within said third area being joined to form a seal having a predetermined width.

25. The apparatus as recited in claim 24, further comprising a third station having a registration point spaced at a distance equal to one or more package widths along said machine direction from said registration point of said second station, wherein said third station comprises a cutting device for cutting said zipper tape and said packaging film material along a straight line intersecting and dividing said third area to separate a package.

26. The apparatus as recited in claim 24, wherein said ultrasonic welding apparatus comprises a horn and an anvil, said horn comprising two prongs separated by a gap, each of said prongs comprising an end surface confronting said anvil, each of said end surfaces having at least a portion that is flat, said flat portions being generally coplanar.

27. The apparatus as recited in claim 24, wherein said conduction heat sealing apparatus comprises a pair of mutually aligned and opposing sealing bars situated on opposing sides of said zipper tape and said packaging film material.