CA2193078C

CA2193078C - Integrated end stops for zipper slider

Info

Publication number: CA2193078C
Application number: CA002193078A
Authority: CA
Inventors: Kevin P. Morgan
Original assignee: Tenneco Plastics Co
Current assignee: Pactiv LLC
Priority date: 1994-06-20
Filing date: 1995-05-04
Publication date: 2001-08-07
Anticipated expiration: 2015-05-04
Also published as: EP0771159A1; DE69523599D1; JP2937482B2; JPH10503672A; DK0771159T3; CA2193078A1; AU2469695A; ES2168365T3; PT771159E; US5442837A; TW303620U; AU678717B2; EP0771159A4; EP0771159B1; DE69523599T2; WO1995035048A1; ATE207714T1

Abstract

A leakproof plastic zipper with integrated end stops for a zipper slider particularly suited for thermoplastic bags.
An increased flange height above the interlocking elements of the zipper and an increased plow depth on the separator of the slider extending down between the flanges provide a means of stopping the travel of the slider past the ends of the zipper. The separator structure depending from the slider has a configuration in vertical cross-section corresponding to an inverted T, the horizontal portion of the T having the ends thereof adapted to be received in window structure in the flanges above the interlocking elements and adjacent one of the integrated end stops.

Description

2 1 93078 W0 9s~3s048 ~ r~n END 3TOP8 FO~ ZIPPER 8LIDER
The present invention relates to i _ u~. ~ in plastic re~~losAhle fastener6 or zippers with sliders for 5 opening and clo5ing the zippers on plastic-film bags and the like. More particularly, the invention relates to a provision of a leakproof plastic zipper with integrated end stops for the ~ipper slider at the ends of the plastic zipper to seal the ends of the zipper and to provide stops to retain the slider on the 10 zipper .
Plastic reclosable fasteners or zippers with sliders are well known in the art. The plastic zippers include a pair of male and ~emale fastener Pl~ L:. in the form of r~ sAhle interlocking rib and groove profile elements for ~ou~eL~tion 15 with the slider for openiDg and closing the rib and groove Pl' L5. In the manufacture of plastic-film bags, a pair of these male and female profile elements eYtend along the mouth of the bag and are secured in any suitable manner to the flF-YihlP walls of the plastic-film bag. These zipper Pl Ls 20 may be integral marginal portions of such walls or they may be ~xLLuded separately and thereafter attached to the walls along the mouth of the bag.
Various aLL~.ny~ c have been utilized heretofore to provide a leakproof plastic zipper and to prevent the slider 25 from sliding off the end of the zipper. ûne aLLCI~I, L is disclosed in US-A-3259951. In this patent, opposing interlocking or mating strips are pP~np~tly joined or sealed to each other at the ends with a separate stop member sealed between these members to stop the longitudinal ~ .. L of the 30 slider therealong. The strips are notched at one end to receive the separating member of the slider.
Another leakproof zipper with slider is ti;qCl~qP~ in ~75-A-5020194. In this patent, the zipper ~LLuul.uLe is slit or notched locally at the end where the slider goes when the zipper 35 is closed to allow the rib and groove Pl ~ Ls to interlock fully making a leakproof closure.
In US-A-5088971 and US-A-5131121 there is disclosed end ~.

Wos~3sO48 ~ ,4 stops that are created from e.xisting material of the profile rib and groove elements at~the opposite ends of the zipper, and that ~Lu~Lude LLal-~v~L~ely from the zipper a distance ~d~yl~Le to engage the sides of the slider and thus prevent - ~ L of the 5 slider past the respective ends of the bag.
In IJS-A-5161286 end clamps are located at the opposite ends of the zipper. A pair of end clamp members is connected together by a fleYible str~ap which extends over the top of the zipper and by a rivet that extends through the pair of end clamp 10 members and the sidewalls of the bag below the profile rib and groove elements of the zipper to secure the end clamp members to the bag.
In ~iS-A-5067208 the plastic reclosable ~astener and slider include end clamp members and a provision for restraining the 15 slider in closed position a~d maintaining the male and female elements of the fastener in interlocking relation when the slider reaches the closed end o its travel along the tracks of the slider Fused plastic end clips for zippers are disclosed in 20 PCT/US94/06417. Tubular plastic end stops for a plastic zipper are disclosed in IJS-A-5405478 . These applications were pllhl i ChQd after the priority date of the present application.
It would be desirable to provide a leakproof plastic zipper with integrated end stops for the zi~per slider wherein the 25 volume of material available at the ends of the rib and groove elements is not only adequate f or f orming integrated end stops without the need for end clamp members but is also adequate to include window structure for receiving the se~dLeltUL finger on the slider thus allowing tlle interlocking elements to close 30 completely beneath the slider and create a leakproof seal. It would also be ~D~ir~h~Q to have the window create a "detent"
effect in the closed position to maintain the slider in the closed position.
It is an obj ect of the present invention to provide an 35 i ~ /ed leakproof plastic zipper with integrated end stops for the zipper slider.
According to the present invFntion there is provided a 2 ~ 93078 w0 95/35048 r~

leakproof plastic zipper with integrated end stops for a zipper slider particularly suit~d for t-h. , lACtiC bags and the. like comprising a pair of fl~Y;hlo plastic 8trips having separable rastener means oYton~in~ along the length thereof comprising 5 ro~ln~hle interlocking rib and groove profile ol~ ~S on the respective strips, 5aid strips each ;n~ n~ profiled flange ~iLLu-LuL~ ~Yto~ n~ along the length thereof r~Allol to the rib and groove ol ~ , a straddling slider on said strips ~or closing or opening the r~ C;-hl e rib and groove ~
10 comprising an inverted U-shaped plastic member having a back for moving along the top edges of the f lange structure with ~r~n~;n~ side walls projecting therefrom for maintaining said flange ~LLUU~UL~ and said rib and groove o~ therebetween, said slider ;n-~ n~ separator ,,LLuuLuL,a ~oron~;n~ from said 15 back and inserted between said flange ,LLu~LuLe to open said rib and groove Pl L~., said sidewalls eYtending from an opening end of the slider to a closi.ng end, the ~;t' 11 = being spaced - wider apart at the opening end to permit separation of the rib ~md groove P~ L~ and being spaced suffic.i-~ntly close together 20 at the closing end to press the rib and groove elements into interlocking relationship ~5 the slider is moved in a zipper closing direction, said ~lange ~LLU- LUL~ and said rib and groove elements being vertically sealed together at both ends of said pair of strips to ~-; nt~; n the zipper closed at said ends and 25 to provide integrated end stops for the zipper slider, and a window structure in said flange aLLu-_LuL~ beneath the top thereof and above said rib a~d groove ~I~ and adjacent one o~ said end stops, said window structure being dimensioned to receive said separator structure at the opening end of said 30 slider whereby when said sli.der is moved in the zipper closing direction, said interlocking rib and groove ~1 L:. are closed tllLvuylluuL the lengt~ of said strips by said closing end of said ~lider and said separator ~LLUULUL~ at said opening end of said slider ic received in sai.d window ~LLU~_LUL~ and thus is 35 ineffective on said flange structure to maintain open said interlocking rib and groove ~ thereby to prevent leakage through said zipper.
~, _ . ~

Woss/3so48 2 1 9 3 0 7 8 P~ . I4 Preferably, 5aid sc~a~aLuL ~tL-u~ LUL~ ~or~n~l;n~ from said back of said slider has a conf iguration in vertical cross-section Cv,~ 1n~J 5ubstantially to an inYerted T, the horizontal portion of said T having the ends thereof adapted to 5 be received in said window :, LL U~: LUL .2.
Desirably, the horizontal portion of the T is shaped to aid in release of the T 5haped portion of said slider from said window structure when 5aid 51ider i5 moved in the zipper opening direction .
Preferably the vertical portion of the T has a thir~n~-qq less than the normal spacing ~etween said flanges when said interlocking rib and groove elements of the zipper are closed.
Reference is now made to the F~ nying drawings, in which:
Fig. 1 is a fractional perspective view of a leakproof plastic zipper with an integrated end stop for a zipper slider mounted on a thermoplastic bag, according to the present invention;
Fig. 2 is a sectional view taken along the lines 2-2 in 2 0 Fig . l;
Fig. 3 is a fr~t~tionAl perspective view similar to Fig. 1 showing the slider at the closed end of the zipper adjacent the integrated end stop;
Fig . 4 is a 5~-f j ~nA 1 view taken along the lines 4-4 in 25 Fig. 3; and Fig. 5 is a sectional view taken along the lines 5-5 in Fig. 3 showing the separator structure that is inserted in the window in the zipper f langes .
Re~erring to Fig. 1, there is illustrated a plastic slider 30 10 and a profiled plastic reclosable fastener or zipper 11 according to the present invention. The slider 10 and zipper 11 are particularly suited for fh~ Aqtic bags and the like and the slider 10 has been illustrated in Fig5. 1 - 4 A~ ed on the zipper 11 at the top end or mouth of a thermoplastic bag 35 B. The bag B may be made from any suitable thermoplastic film such for example as polyethylene or polypropylene or eSIuivalent material .
=
~ `- - !

2~ 93078 W0 9jl3s048 t-~ 4 The bag B is formed by a p2ir o~ f 3 exible plastic sheets 12 and 13, Fig. 2, joined at the bottom and having a top edge, with a pair of f lexible pla8tic strips 14 and 15 having ~eparable plastic means extending along the length thereof 5 comprising re~ Ahle interlocking male ~md female profile ~1 Ls in the form of rib and groove ~ s 16 and 17 on the respective strips to form the zipper ll. The strips 14 and 15 may be ~,LL uded separately,and attached to the respective sides of the bag mouth or the strips i4 and 15 may be extruded 10 integral with the sides of the bag mouth.
The strips 14 and 15 include profiled flanges or tracks 18 and 19 extending along the ] ength thereof parallel to the rib and groove elements 16 and 17. The profiled flanges 18 and 19 have Dub:,L~ ial depth the purpose o~ which will be ci;ccllcsecl 15 below . The rib and groove prof iles 16, 17 may be of the type disclosed in US-A-5007143.
As may be seen in Figs. 1-4, the slider 10 straddles the zipper 11 at the top of the bag B and is adapted for opening or closing the ret-lOGAhl~ fastener ~ 16 and 17 of the ~ipper 20 11. The slider 10 may be formed from a 8ingle piece of moulded plastic comprising a 5~ 1La~UL DLt U~.~UL~ 9 and interlocking compl L~ly ~LU~_LU' : for moving along the zipper 11. The separator ~Lt U-:LUL ~ 9 cc,~ L~.tes with the zipper 11 in such a manner as to provide a self-locking feature for the slider and5 a leakproof bag as hereinafter to be described in more detail.
The slider 10 may be of similar construction to the slider disclosed in US-A-5067208 e~cept for the cul-~LLu~:~ion of the separator ~LLU-,LU1~ 9. The slider 10 may be moulded from any suitable plastic such, for example, as nylon, polypropylene,0 poly ,~y L ~=I.e, Delrin or ABS.
The Dlider 10 comprises an inverted U-shaped plastic member having a back 20 for moving along the top edgec of the ~lange DLLu~uLe 18 and 19 with d~r~nfling side walls ~~ and 22 projecting therefrom for maintaining the flange structure 18 and 35 19 and the rib and groove elements 16 and 17 th~ bet _en. The 51fl' '=llG 21 and 22 preferably are pivoted at their upper ends to the back member 20 and ~t their lower ends have inwardly .

W0 gs/3s048 ~ 2 1 9 3 0 7 8 r ~u ;. . /4 extending ch~ ARrs 21a and 22a to maintain the slider 10 on the zipper. This is best seen in Fig. 2. As shown in Fig. 1, the sidewalls 21 and 22 extend from an opening end lOa of the slider to a closing end lOb with the sidewalls 21 and 22 being spaced 5 wider apart at the opening end lOa to permit 5eparation of the rib and groove element5 16 and 17 and being spaced sufficiently close together at the closing end lOb to pre5s the rib and groove ~ ' 16 and 17 into interlocking r~lati~-nh;r as the slider 10 i8 moved in a zipper closing direction. The slider 10 10 in~ A~ separator 5tructure 9 d~p~nAing from the back 20 and inserted between the flange 5tructure 18 and 19 to open the rib and groove elements.
The separator 9 has a conf iguration in vertical cross-section ~uLL~ A;n~ substantially to an inverted T, ;nr~ A;n~
15 ~ vertical portion 9a and a llorizontal portion 9b. It will be seen that the vertical dimension of the vertical portion 9~ of the separator is sufficiently great so as to support the horizontal portion 9b at a substantial distance below the top of the flanges 18 and 19. The purpose of this will hereinafter 20 be pointed out. Also it will be noted that the ~h;r~n-.-:c of the vertical portion 9a is sufficiently thin U~LUUYIIUU~ its length 50 as not to 5pread the spacing between the flanges 18 and 19 which would cause an opening of the interlocking rib and groove elements 16 and 17. The only portion of the separator structure i5 9 which is effective to spread the flanges 18 and 19 and thereby cause opening of the rib and grQove elements 16 and 17 is the horizontal portion 9b.
As may be seen in Fig. 1 the portion 9b of the separator at the opening end lOa of the ~lider is sufficiently wide so a5 30 to spread the flanges 18 and 19 and thereby in turn open the rib and y-roove elements 16 and 11. It will be noted that the section along which Fig. 2 is taken in Fig. 1 is at a location int~ --;ate the end5 of the horizontal portion 9b of the separator. At this section as shown in Fig. 2, the width of the 35 portion gb is sufficiently narrow to permit the flanges 18 and 19 to be moved close together and thus close the interlocking elements 16 and 17. As may be seen in Fig. 1 the end of the ~w0 95135048 2 1 9 3 0 7 8 . r ~ 4 zipper to the left or the slider lo is still maintalned open by the horizontal portion 9b of the separator.
As pointed out above, the flange DLLu~ ~ur~ 18, 19, on the strips 14, 15, has a substantial depth as shown in Fig. 1.
5 The purpose of this is two fold. The first is to provide sufficient area to form a window ~LLU~,LU~: 18a and l9a therein for receiving the horizontal portion 9b of the s~aLatc,L. The second is to provide suf f icient plastic material so that when the flanges 18 and 19 and the rib and groove el~ ~ 16 and 17 10 are vertically sealed together at the ends of the pair of strips, the zipper 11 will be r-;nt~inPcl closed at those ends nnd will provide integrated end stops 23 for the zlpper slider.
It will be understood that the flange structure and rib and groove elements at the opposite ends of the strips, not shown, 15 are also vertically sealed together to provide an integrated end stop at the opposite end of the zipper for the slider. The win;iow structure 18a and l9a is framed within the flange str ~ture 18 and 19 and is located beneath the top thereof and above the rib and groove elements 16 and 1~ adjacent the e~d 20 stop 23. The window ~I~LU~,~UL_ 18a, l9a is f~ir -1-n~d ta receive the separator portion 9b at the opening end i Oa of the slider 10, Fig. 3, whereby when t le slider 10 is moved in the zipper closing direction, the interlocking rib and groo~e pl ~s 16 and 17 are closed Llllu~ u~ the length of to 25 strips 14 and 15 by the closing end lOb of the slider and the separator portion 9b at the opening end of the slider is received in the window structure 18a, l9a. This is best shown in Figs. 3-5. It will be seen that the S~:~aLa-UL portion 9b, since it extends into the windows 18a, l9a, is now ineffective 30 cn the flange structure 18 and 19 to maintain open the interlocking rib and groove elements 16 and 17 thereby preventing leakage through the zip~er.
Referring to Fig. 5 it will be seen that the &eparator portion gb is positioned at the end of the zipper in the windows 35 18a, l9a of the flanges 18 and 19. ~hus the slider 10 is in the fully closed position for the zipper _1. In order to aid ill the release of the separator ~LLU-,LUL.' 9 from the window ~LLU~,~ULe ;
_ _ _ _ _ _ _ _ _ _ _ _ . . . .. , . _ . ... . . . .. ..

~ WO g5J35048 2 1 q 3 0 7 8 r~ /4 18a, l9a, the forward end of the portion 9b i5 shaped at 9c as by a curve or chamf er to aid in separating the f langes 18 and 19 as the slider 10 is moved in an opening direction on the zipper. Thus the window ,.~lu~;LuLe 18a, l9a creates a "detente"
5 effect on the slider when in the closed position.
In US-A-5067208 and US-A-5161286 additional end clamps or clips were ~t;~;70~1 at the ends of the zipper to ensure that the bag was leakproof. In those applications, each flange was about 0.060" (1.5 mm) high and they were located a~ove each of the 10 interlocking elements. The interlocking ~l L:. were opened with a separator finger on the slider extending about 0.050"
(1.3 mm~ down between the flanges.
In the present invention the height of each flange 18, 19 is increased up to 0.500" (12.7 mm) and the depth of the slider 15 separator structure 9 is increased up to 0.500" ~12.7 mm) and is f lared out at the bottom 9b to be received in the window structure 18a, l9a in the flanges. By increasing the height of the flanges 18, 19, there is adequate plastic material in them to form integrated end stop seals 23 at the ends of the zipper.
20 These end seals 23 are sufficiently strong to provide a leakproof closure at the ends of the zipper without requiring additional end clips or clamps as rii~ C~fl in tJS-A-5067208 and US-A-5161286. The use of windows 18a, l9a in the flanges, as distinguished from a notch or slit as ~ cl~s~A in US-A-5067208 and US-A-5020194, maintains the integrity of the flange structure adjacent the end seals and aids in ensuring the leakproof closure of the zipper. The side seal flanges 23 and the extended separator structure 9 provide an end stop to the slider 10 at both ends of the bag.
The present invention has various advantages over the prior art. For example in manufacture, the cost of the extra plastic end straps is eliminated, several of the heat sealing operations are eliminated, and the station for applying the plastic end straps is eliminated. Registration is less critical during the 35 ~ ~ L of the bag web through the bag making machine and the appearance of the finished bag i8 also; ~ v~:d.
While a preferred F~ oAi L of the invention has been Wo 9s~048 P~ 4 ~ 2193078 described and illu5trated, it is to be understood that ~urther modif ications thereof may be made within the scope of the ClA~

.

Claims

1. A leakproof plastic zipper with integrated end stops for a zipper slider particularly suited for thermoplastic bags and the like comprising a pair of flexible plastic strips having separable fastener means extending along the length thereof comprising reclosable interlocking rib and groove profile elements on the respective strips, said strips each including profiled flange structure extending along the length thereof parallel to the rib and groove elements, a straddling slider on said strips for closing or opening the reclosable rib and groove elements comprising an inverted U-shaped plastic member having a back for moving along the top edges of the flange structure with depending side walls projecting therefrom for maintaining said flange structure and said rib and groove elements therebetween, said slider including separator structure depending from said back and inserted between said flange structure to open said rib and groove elements, said sidewalls extending from an opening end of the slider to a closing end, the sidewalls being spaced wider apart at the opening end to permit separation of the rib and groove elements and being spaced sufficiently close together at the closing end to press the rib and groove elements into interlocking relationship as the slider is moved in a zipper closing direction, said flange structure and said rib and groove elements being vertically sealed together at both ends of said pair of strips to maintain the zipper closed at said ends and to provide integrated end stops for the zipper slider, and a window structure in said flange structure beneath the top thereof and above said rib and groove elements and adjacent one of said end stops, said window structure being dimensioned to receive said separator structure at the opening end of said slider whereby when said slider is moved in the zipper closing direction, said interlocking rib and groove elements are closed throughout the length of said strips by said closing end of said slider and said separator structure at said opening end of said slider is received in said window structure and thus is ineffective on said flange structure to maintain open said interlocking rib and groove elements thereby to prevent leakage through said zipper.

2. A leakproof plastic zipper according to claim 1, wherein said separator structure depending from said back of said slider has a configuration in vertical cross-section corresponding substantially to an inverted T, the horizontal portion of said T having the ends thereof adapted to be received in said window structure.

3. A leakproof plastic zipper according to claim 2, wherein said horizontal portion of said T is shaped to aid in release of said T shaped portion of said slider from said window structure when said slider is moved in the zipper opening direction.

4. A leakproof plastic zipper according to claim 2 or 3, wherein the vertical portion of said T has a thickness less than the normal spacing between said flanges when said interlocking rib and groove elements of the zipper are closed.