Note: Descriptions are shown in the official language in which they were submitted.
F-6137-L(PAC)
1
Plastic Reclosable Fastener with Structure for Retain~xor
Slider in Closed Position
The present invention relates to a fastener struc4~re for a
thermoplastic bag. The invention particularly relates to fastener
structures of the type known as zippers.,
A conventional metal zipper has a tab on its slider. Folding dorPm the
tab locks the zipper so it will not unzip. Such a featm-e has not
hitherto bean provided on a plastic zipper, even though plastic
zippers with sliders are well known in the art.
Plastic zippers have profiles and include a pair of male and female
fastener el~errts in the form of reclosable interlocking rib and
groove elf with a slider for opening and closing the rib and
groove elements. In the manufacture of a thermoplastic film bag, a
pair of these male and female fastener elements extend alorx3 the mouth
of the bag, the male and female elements being adapted to be secured
in any suitable manner to the flexible walls of the thermoplastic film
bag. The elements may be 1 marginal portions of sucks walls or
they may be extruded separately and thereafter attached to the walls
along the mouth of the bag. A method of continuously providing such a
fastener on the thermoplastic film is disclosed in US A-3462332. In
US-A-3259951 there is disclosed an example of a thermoplastic bag
where the fastener elements are extruded separately and thereafter
attarh~i to the walls along the moaxth of the bag. This patent also
discloses a slider and flexible closure strips adapted to be joined by
such slider to form an airtight clue.
The sliders for opening or closing the reclosable fastea~xs are
adapted to be assembled with the zipper by an endwise assembly or by a
relative transverse manoeuvre. An example of a fastener with an
endwise assembly of the slider is disclosed in US-A-3259951. In s
instances the sliders are formed of multiple parts and assembled on
the zipper. The assembly may be si~lified if the slider is formed of
F-6137-L(PAC)
2
one part and the sides are foldable into position when assembled on
the zipper.
It is an object of the present invention to provide a fastener
structure for a thermoplastic bag, in which the fastener structure can
be aa~l closed by a slider and wherein ooaperatirig latching
structure is provided to provide the feel of a secure closure when the
slider has reached the closed position on the zipper.
According to one aspect of the invention there is provided a fastera~x
structure for a thermoplastic bag, ccs~rising a pair of flexible
plastic strips having separable fastener means extending along the
length thereof o~prising r~losable interlocking male axed female
profile elements on the respective strips, said male and female
elements having o~nplimentary cross sectional shapes such that they
are closed by pressing the elements together, a straddling slider on
said strips for closing the reclosable male arx3 female el~ents, and
latrhirxg means for retaining said slider in closed position when said
slider reaches the closed end of its travel along said plastic strips,
said latchiryg means ccm~rising a ooopexatirig detent structure on said
slider and at least one of said plastic strips, said detent structure
being spaced from said male and female interloc7ti.ng elements and beaaxg
ettgageable when said slider is at the closed end of its travel on said
plastic strips.
Preferably said cooperating detent structure comprises notched
structure on said slider and cooperating protrusion stru~e on said
at least one plastic strip.
nesirably a pair of said notched structures are provided on said
slider for fixating with protrusion structures on both of said
plastic stxips.
It is preferred that the slider is made of plastic.
F-6137-I~(PAC) 3 2~~~~~~
Acc~rdirag to another aspect of the irnrention there is provided a
thermoplastic bag prising a pair of facing sidewalk defining an
open mouth at one end of the bag, and a fastener structure as
described above disp~ed along the mouth for c~ening and closing said
mouth.
Reference is naa made to the aco~panying drawings, in which:
Fig. 1 is a fractional perspective view of a plastic bag with a
fastener structure according to the present invention;
Fig. 2 is an elevational view of the fastener structure shown in Fig.
1; and
Fig. 3 is a sectional view taken along the lines 3-3 in Fig. 2.
Referring to Fig. 1, there is illustrated fastener structure
comprising a plastic slider 10 and a profiled plastic reclosable
fastener 11. The slider 10 and fastener 11 are particularly suited for
thermoplastic bags and the like and the slider l0 has been illustrated
in Figs. 1 and 2 assembled on the fastener 11 at the top edge or mouth
of a thermoplastic bag B. The bag B may be made frcan any suitable
thermoplastic film such for example as polyethylene or polypropyler~
or equivalent material.
The bag B is formed by a pair of flexible plastic sheets 12 and 13
joined at the botto;n and having a top edge, with a pair of flexible
plastic strips 14 and 15 having separable plastic means extending
along the length thereof prising reclcsable interlocking male and
female profile elements zn the form of rib and groove elements 16 and
17 on the respective strips to form the fastener 11. The strips 14 and
15 may be extruded separately and attached to the respective sides of
the bag mouth or the strips 14 and 15 may be extruded airtegral with
the sides of the bag myth. The strips 14 and 15 incl~ie profiled
tracks 18 and 19 extending along the length thereof para11e1 to the
rib and groove elements 16 and 17 and the rob and groove el~er~ts, 16,
F-6137-L(PAC)
4
17 have cxettplementary cross-sectional shapes such that they are closed
by pressing the elements together with the slider 10.
The Gross-sectional shapes of the intexlockir~g male and female
elements having the rib and groove profiles 16 and 17 may be of any
type but preferably are of the type disclosed in Wm-91/13564.
As may be seen in Fig. 1 the slider 10 straddles the fastener 11 at
the top of the bag B and is adapted for opening ar closing the
reclosable fastener element 16 or 17 of the fastener 11. The slider 10
is formed from a single piece of moulded plastic c~prising a
separator finger 9, Fig. 2, and interlocking ocmiplementary structure
moving along the fastennx 11. The slider 10 may be moulded from any
suitable plastic such for example as nylon, polypropylene,
polystyrene, Delrin or ABS.
In the preferred embodiment the ccmiplementary structure comprises an
inverted U-shaped member includi~ a transverse supported member or
body 20 fr~n which the separator finger 9 depends. The body 20 is
itself U-shaped and includes two integral spac~l d 1
ependiryg egs 20a
and 20b (not shown). the finger 9 is positioned betw~n the legs 20a,
20b. The body 20 is adapted to move along the top edges of the tacks
18 and 19 with the legs 20a, 20b straddling these elements and the
finger 9 positioned betw~n the tracks 18 and 19. The body 20 also
includes a pair of hinged °°wings°° or side walls
21 or 22 that can he
folded down into their final position.
The wings 21 and 22 are hinged to the main slider body 20 by means of
hinge structure located at the opposite ends of the legs 20a and 20b.
The wings 21 and 22 have central openings into which the legs 20a, 20b
esctend arxi the wings 21 and 22 are folded down into their final
position as shown in Fig. 1. When the sidewalk 21 and 22 are in the
folded position as shoam in Fig. 1 a compression-type latGhirr~
m~hanism (not shoran) locks the sidewalls 21 and 22 in folded position
with the depending legs 20a and 20b. In this assembled position, the
shoulders 21c and 22c on the sidewalls 21 and 22 are positioned
F-6137-L(PAC)
beneath the bottcan of the fastener elements 16 and 17 to prevent the
slider 10 from being lifted off the fastener 11. The foldable
depPxxling sidewalk 21 and 22 extend from an opening end l0a of the
slider 10 to a closing end lOb.
The sidewalk 21 and 22 and the depending legs 20a and 20b are spaced
wider apart at the ~ end l0a of the slider 10 to permit the
separation of the rib aryl groove elements 16 and 17 by the finger 9
engaging the tracks 18 and 19 arxi are spaced sufficiently close
together at the closing end 10b of the slider to press the rib and
groove elements 16 and 17 into interlocking relationship as the slider
is mov~l in a fastener closing direction from the position in Fig.
1 to the closed position in Fig. 2.
As may be seen in Figs. 1-3 the extruded stxips 14 and 15 have been
provided with protrusions 14p and 15p which exterr3 outwardly fr~n the
surface of the strips 14 and 15. The protrusions 14p and 15p are
shaped to be received within the corresponotches or indentations
21n and 22n formed in the lacer portions of the sidewalls 21 and 22 of
the slider 10. As may be seen in Figs. 1 arr3 3 the notches 21n and 22n
are formed in the oppose vertical surfaces of the shoulders 21c and
22c.
The ends of the notches 21n and 22n are flared at the opening end 10a
of the slider 10, Fig. 3, to provide a funnel shaped caning to permit
the protrusions 14p and 15p to enter the notches 21n and 22n as the
slider 10 moves to the closed end of the fastener 11, Figs. 2 and 3.
The protrusions 14p and 15p are spaced with respect to the closed end
of the fastener 11 so that when the slider 10 reaches the end of its
travel on the fastener 11 in the closir~g direction, the protrusions
14p and 15p will be received in the notches or ~tior~s 21n and
22n. This gives the user of the bag assurance that the bag is closed
with certainty. If the fastener 11 is not provided with end stops the
cooperating protrusions and notches will serve to keep the slider frc~n
going past the closed end of the fastener and caning off of the bag.
~~~a~~~~
F-6137--L (PAC)
6
The apposite ends of the fastexier 12 may be p~rov~id~ with end stc~s 30
formed frc~n the material at the bite ends of the faster~x 11 and
pratnxde frcan the fastener a distance adequate to engage the slider 10
to prevent the slider frcera going past the respective ends of the
fastener and c~i.ng off of the bag. When the fastener 11 is provided
with end stops 30 the protrusions 14p and 15p are spaced with r
to the closed end stc~ 30 of the fastener 11 so that rahen the slider
reaches the end of its travel on the fastener 11 in the closing
direction, the protrusions 14p and 15p will be received in the notches
or indentations 21n or 22n.
While one type of cooperating detent structure has been described and
illustrated in respect to the slider and the plastic strips, it is to
be understood that other cooperating detent structure may be utilised
for performing the same function, namely providing the user of the bag
with the feel of a secure closure. The protrusions and indentations
disclherein for providing the cooperating detent structure may be
positioned at other locations than those shoran.
