Plastic reclosable fastener with structure for restraining slider in closed position and for facilitating reopening fastener

A plastic reclosable fastener with slider for opening and closing the reclosable fastener on plastic-film bags and the like is disclosed. The plastic reclosable fastener and slider include a provision for restraining the slider in closed position and thereby maintaining the male and female elements of the fastener in interlocking relation to avoid inadvertent opening of the elements of the fastener when the slider reaches the fully closed position at the end of its travel along the fastener. The ends of the flanges of the fastener that are created by the slider-restraining notch are provided with diverging structure to facilitate re-entry of the slider separator structure between the flanges when the slider is moved toward the opposite end of the fastener to open the male and female elements of the fastener.

BACKGROUND OF THE INVENTION 
The present invention relates to improvements in plastic reclosable 
fasteners with sliders for opening and closing the reclosable fasteners on 
plastic-film bags and the like and particularly to detent structure for 
restraining the slider in closed position when the slider reaches the 
fully closed position at the end of its travel along the reclosable 
fastener and for facilitating reopening of the fastener. 
Plastic zippers with sliders are well known in the art. The plastic zippers 
have a pair of male and female fastener elements in the form of reclosable 
interlocking rib and groove elements with a slider having separator 
structure for opening and closing the rib and groove elements. In the 
manufacture of plastic-film bags, a pair of these male and female fastener 
elements extend along the mouth of the bags and these male and female 
elements are secured in any suitable manner to the flexible walls of the 
bags. These elements may be integral marginal portions of such walls or 
they may be extruded separately and thereafter attached to the walls along 
the mouth of the bag. It frequently is desirable that the plastic-film 
bags be leakproof. One example of a plastic-film bag having a slider and 
flexible closure strips adapted to be joined by such slider to form an 
air-tight closure is disclosed in U.S. Pat. No. 3,259,951--Zimmermann. 
Another example of a plastic-film bag with a leakproof zipper and slider 
is disclosed in U.S. Pat. No. 5,020,194--Herrington et al. For leakproof 
plastic-film bags it also is desirable that the bags include structure for 
retaining the slider in closed position. Examples of this type 
construction are disclosed in U.S. Pat. No. 5,067,208--Herrington et al 
and U.S. Pat. No. 5,189,764--Herrington et al. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a plastic-film bag with 
a zipper that is operated by a slider wherein cooperating restraining 
structure is provided on the zipper and the slider to restrain the slider 
in closed position when the slider reaches the fully closed position at 
the end of its travel along the zipper and to facilitate reopening of the 
zipper when the slider is moved toward the opposite end of the zipper. 
The present invention relates to a plastic reclosable fastener with slider 
particularly suited for plastic-film bags and the like for closing or 
opening the reclosable fastener or zipper and for restraining the slider 
in closed position when the slider reaches the fully closed position at 
the end of its travel along the fastener. The reclosable fastener 
comprises a pair of flexible plastic strips having separable fastener 
means extending along the length thereof comprising reclosable 
interlocking male and female profile elements on the respective strips. 
The strips include flanges extending along the length thereof parallel to 
the male and female elements. A straddling slider is positioned on the 
strips for moving along the fastener in straddling relation to open or 
close the reclosable interlocking male and female elements. The slider 
comprises an inverted substantially U-shaped plastic member for moving 
along the top edges of the fastener with depending sidewalls that 
comprises the two legs of the U maintaining the flanges and the male and 
female elements therebetween and a support member that comprises the base 
of the U. The sidewalls extend 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 male and female elements and being spaced 
sufficiently close together at the closing end to press the male and 
female elements into interlocking relationship as the slider is moved in a 
fastener-closing direction. The slider includes separator structure 
depending from the support member and inserted between the flanges to open 
the male and female elements. The separator structure is located at the 
opening end of the slider. Restraining means is provided for restraining 
the slider in closed position and thereby maintaining the male and female 
elements in interlocking relation when the slider reaches the fully closed 
position at the end of its travel along the fastener comprising notched 
structure at the end of the flanges adapted to receive the separator 
structure when the reclosable fastener is in closed condition. The ends of 
the notched flanges are deformed so as to diverge outwardly. The separator 
structure is engageable with the diverging ends of the notched flanges 
when the slider is at the fully closed position at the end of its travel 
on the fastener thereby restraining the separator structure from moving 
out of the notched structure to a position between the flanges and thus 
preventing inadvertent opening of the male and female elements of the 
fastener. The separator structure is constructed and arranged so as to 
spread the diverging ends of the notched flanges and thereby facilitate 
reentry of the separator structure between the flanges when the slider is 
moved toward the opposite end of the fastener so as to open the male and 
female elements of the fastener. In the preferred form of the invention 
the separator structure is of cylindrical shape. 
Other objects and advantages of the invention will become apparent from the 
following detailed description of the invention taken in conjunction with 
the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 3 there is illustrated a plastic slider 10 and a 
profiled plastic reclosable fastener or zipper 11 embodying the present 
invention. The slider 10 and zipper 11 are particularly suited for 
plastic-film bags and the like and the slider 10 has been illustrated in 
FIGS. 1 and 3 assembled on the zipper 11 at the top edge or mouth of the 
plastic-film bag B. The bag B may be made from any suitable plastic-film 
such for example as polyethylene, polypropylene or similar material. The 
bag B is formed by a pair of flexible plastic sheets 12 and 13 joined at 
the bottom and having a top edge or mouth, with a pair of flexible plastic 
strips 14 and 15 having separable plastic means extending along the length 
thereof comprising reclosable interlocking male and female profile 
elements in the form of rib and groove elements 16 and 17, FIG. 3, on the 
respective strips to form the zipper 11. The strips 14 and 15 may be 
extruded separately and attached to the separate sides of the bag mouth or 
the strips 14 and 15 may be extruded integral with the sides of the bag 
mouth. The strips 14 and 15 include flanges 18 and 19 extending along the 
length thereof parallel to the rib and groove elements 16 and 17 and the 
rib and groove elements 16 and 17 have complementary cross-sectional 
shapes such that they may be closed by pressing the elements together by 
means of the slider 10. The cross-sectional shapes of the interlocking 
male and female elements having the rib and groove profiles 16 and 17 may 
be of any suitable type. One example of a suitable type is disclosed in 
the aforesaid U.S. Pat. No. 5,067,208. 
It is to be understood that the present invention is not limited to the 
shapes of the rib and groove profiles illustrated herein and that other 
shapes may be utilized in connection with the present invention. It also 
is to be understood that the present invention is not limited to the 
particular construction of the slider 10 disclosed herein except as 
defined in the appended claims and that other zipper sliders may be 
utilized in connection with the present invention and particularly the 
manner of assembly of the sliders with the zipper. 
As may be seen in FIGS. 1 and 3 the slider 10 straddles the zipper 11 at 
the top of the bag B and is adapted for opening or closing the reclosable 
fastener elements 16 or 17, shown in FIG. 3, of the zipper 11. For 
purposes of explanation, the slider 10 has been illustrated in simplified 
form and only the structure which particularly relates to the present 
invention will be described in detail. In general, the slider 10 may be of 
similar construction to the slider disclosed in the aforesaid U.S. Pat. 
No. 5,067,208 except for the construction of the separator finger 9 as 
hereinafter described in detail. The slider 10 preferably is formed from a 
single piece of molded plastic comprising a substantially U-shaped plastic 
member for supporting the separator finger 9 and moving it along the 
zipper 11. The slider 10 may be molded from any suitable plastic such for 
example as nylon, polypropylene, polyethylene, polystyrene, Delrin, or 
ABS. 
Referring to FIG. 1, it will be seen that the slider 10 comprises an 
inverted U-shaped member including a transverse support member 20 from 
which the separator finger 9 depends. The slider includes two depending 
sidewalls 21 and 22. The separator finger 9 preferably is cylindrical in 
shape and is positioned between the sidewalls 21 and 22. The slider is 
adapted to move along the top edges of the strips 14 and 15 with the 
sidewalls 20 and 21 straddling the fastener elements 16 and 17 and the 
separator finger 9 positioned between the flanges 18 and 19 as shown in 
FIG. 3. As may be seen in FIG. 3 the bottoms of the sidewalls 21 and 22 
are provided with inwardly extending shoulders 21a and 22a which are 
positioned beneath the bottom of the fastener elements 16 and 17 of the 
zipper 11 to prevent the slider 10 from being lifted off the zipper 11. 
The depending sidewalls 21 and 22 extend from an opening end 10a of the 
slider 10 to a closing end 10b. It will be noted that the finger 9 is 
supported by support member 20 at the opening end 10a of the slider 10. 
The sidewalls 21 and 22 are spaced wider apart at the opening end 10a of 
the slider to permit the separation of the rib and groove fastener 
elements 16 and 17 by the finger 9 engaging the tracks 18 and 19 and are 
spaced sufficiently close together at the closing end 10b of the slider to 
press the rib and groove fastener elements 16 and 17 into interlocking 
relationship as the slider is moved in a fastener-closing direction from 
the position shown in FIG. 3 to the fully closed position shown in FIG. 1. 
In accordance with the present invention there is provided means for 
restraining the slider 10 in closed position and maintaining the male and 
female elements of the zipper in interlocking relation when the slider 10 
reaches the fully closed position at the end of its travel along the 
strips 14 and 15 as shown in FIG. 1. It will be noted in FIGS. 1 and 2 
that the flanges 18 and 19 are provided with notched structure adapted to 
receive the separator finger 9 when the reclosable fastener 11 is in 
closed condition. The ends of the flanges 18 and 19 created by the 
structure are deformed at 18a, 19a so that the ends of the flanges 18a and 
19a diverge outwardly. This is clearly shown in FIGS. 1 and 2. It also 
will be seen in FIGS. 1 and 2 that the separator finger 9 is engageable 
with the diverging ends 18a, 19a of the flanges 18 and 19 created by the 
notched structure when the slider 10 is at the fully closed position at 
the end of its travel on the flanges 18 and 19 thereby resisting movement 
of the separator finger 9 out of the notched structure to a position 
between the flanges 18 and 19 and thus resisting inadvertent opening of 
the male and female elements of the fastener 11. It will be noted in FIGS. 
1 and 2 that the separator finger 9 is cylindrical in shape and thus when 
the slider 10 is moved to the closed end of its travel as shown in FIGS. 1 
and 2 there is no separator structure engaging the flanges 18 and 19. This 
permits the fastener to be completely closed. In the aforesaid U.S. Pat. 
No. 5,067,208 the separator finger disclosed therein includes a 
cylindrical portion and also a narrower portion which remains between the 
flanges of the zipper when the separator finger of the slider is within 
the notch at the end of the zipper. In that patent the engagement of the 
narrow section of the separator finger with the flanges facilitates 
re-entry of the cylindrical portion of the finger back between the flanges 
of the zipper during opening. In the present invention the narrow portion 
of the separator finger has been eliminated and the separator finger 9 
shown herein in FIGS. 1 and 2 engages the diverging ends 18a, 19a of the 
flanges 18 and 19 at the notch structure and thereby facilitates re-entry 
of the separator finger 9 between the flanges 18 and 19 when the separator 
finger 9 is moved toward the opposite end of the tracks to open the male 
and female elements of the fastener 11 as shown in FIGS. 3 and 4. 
While a preferred embodiment of the invention has been described and 
illustrated, it is to be understood that further modifications thereof may 
be made within the scope of the appended claims without departing from the 
spirit of the invention.