Plastic Reclosable Fastener With Structure for Restraining Slider in Closed Position and for Facilitating Reopening Fastener

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.

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.

FIG. 1 is a fractional perspective view of a plastic-film bag with a plastic reclosable fastener and slider constructed in accordance with the present invention with the slider in its fully closed position at the end of fastener.

FIG. 2 is a sectional view taken along the lines 2--2 in FIG. 1.

FIG. 3 is a fractional perspective View of the present invention similar to FIG. 1 and showing the slider moved to a partially open position on the reclosable fastener.

FIG. 4 is a sectional view taken along the lines 4--4 in FIG. 3.

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.