US 3310224 A
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Description (OCR text may contain errors)
arch 21, 1967 K. LAGUERRE 3,310,224
BAG AND CLOSURE MEANS THEREFOR Original Filed Feb. 4, 1964 FIG.2
HIS ATTORNEY FIG. 3
United States Patent 3,310,224 BAG AND CLOSURE MEANS THEREFOR Leon Ker Laguerre, Rue Lemoine, Boulogne-sur-Seine, France Continuation of application Ser. No. 342,493, Feb. 4, 1964. This application Apr. 20, 1966, Ser. No. 544,039 4 Claims. (Cl. 22954) This invention relates to a bag, and more particularly is concerned with a plastic bag and a combination handle and closure means therefor.
Various types of bags are known in the art, including numerous kinds made of thermoplastic material. Many of the bags of the prior art include a combination handle and closure means for the bag which makes it possible to provide a tight closure thereof so that its contents cannot readily be lost nor can dirt or moisture readily enter the bag.
It is also well known in the art to provide bags whose main body portion is formed of a thin film of thermoplastic material such as the more common vinyl plastics. The prior art further teaches the use of a combination handle and closure means for such a thin-film plastic bag which is welded or cemented or otherwise fastened to the .thin film. It is also common to fabricate the handle and closure means from a vinyl plastic having a substantially heavier gauge than that of the thin film used for the main portion of the bag since this provides greater strength and provides a desirable rigidity to the mouth of the bag, thereby making it more convenient to open the bag and to maintain it open for obtaining access to the bags interior.
In addition to the foregoing, it is also known in the art to provide a combination handle and closure means which consists essentially of two generally congruent strips of a semi-rigid material such as a fairly heavygauge plastic which are welded or heat-sealed to the mouth of the bag. To open the bag, it is then only necessary to grasp the two handle portions with ones right and left hands, respectively, and separate the two handle portions.
Quite often, a securing or locking means is employed which tends to hold the two oppositely disposed handle portions together, thereby effectively maintaining a tight closure of the mouth of the bag. form, such a fastening means may comprise a small protuberance on one member which frictionally engages an indentation or recess in the opposite member as is, for example, shown in the patent of Harrah, No. 2,978,769. To open a bag which is provided with such a closure means, it is again only necessary to separate the two handle portions, but now, obviously, somewhat more force is required to accomplish this because the fasteners must first be unsnapped.
Extensive experience has shown, however, that the type of bag construction described thus far has several disadvantages. If the just-described fastening means is to be effective to maintain the top of the bag tightly closed under normal conditions, it is then also necessary that a fairly considerable force must be exerted on the two members comprising the handle and closure means in order to unsnap the fasteners and open the mouth of the bag. It has been found that when this is done, the natural muscular action of the user results in an abrupt and sudden further spreading of the mouth of the bag when the fasteners release, with the resulting application of large forces at the extreme ends of the two closure strips. These forces are naturally applied to the side walls of the thin-film main bag portion and easily result in tearing this member. Previous attempts to solve this problem have comprised inserting a rivet or other fastening means through the two strips at their respective extreme ends so that such rivets, instead of the thin plastic In its most practical 3,310,224 Patented Mar. 21, 1967 ICC film, will bear these forces. Of course, the use of such rivets or equivalent fastening means is not entirely satisfactory because of the increased cost of manufacture of each bag and the lessening of the bags attractiveness and eye appeal.
Accordingly, it is a feature of this invention to provide a plastic bag or container whose main body or bag portion is formed of a thin film of thermoplastic material having front and rear bag walls, together with a combination closure and handle means which comprise a unitary element rather than the two-piece element used heretofore. The unitary element is preferably formed of a thermoplastic material such as the common vinyl plastic but is considerably heavier in gauge than that used to form the main bag portion so that the unitary element has a very much higher tensile strength than the bag walls. The act of opening the bags mouth causes the resulting forces to be borne fully by the unitary handle and closure means which can readily withstand the stress because of its high tensile strength, and no forces are applied to the thin-film main bag portion so that its tearing is prevented.
The unitary closure means is constructed so as to comprise two substantially congruent strips each having a length substantially equalling the width of the front and rear bag walls at the mouth of said bag. These two strips normally overlie each other and are joined at their extreme ends by means which is integral with both the strips, and holds the strips closely adjacent each other and parallel to each other at their ends. Because of the parallel relationship of the ends of the strips and because of the resilience of the material which forms the unitary closure means, any attempt to open the mouth of the bag by separating the two strips at their mid-por tions results in curvature of the strips over substantially their entire length, but with substantially less curvature taking place near the ends.
The effect is similar to that of a cantilever construction in which each strip is quite tightly held at its end portion and deflection forces are applied to it at a point remote from the end; with such construction, there is substantial deflection over the length of the member but a minimal amount at the anchored end. In the bag and closure means construction of the present invention, this results in a substantially uniform distribution of forces over the length of each of the strips included in the unitary closure means when the bag mouth is opened, and prevents a concentration of forces at the respective ends which, even though the material is flexible and not brittle, would otherwise result in substantial flexure taking place at such ends so that rupture would quickly occur there.
Another advantage of the described construction of the unitary closure means is that the maintenance of the ends in substantially parallel relationship by the means which joins the two strips cooperates with the flexibility of the material included in the unitary closure means to cause the mouth of the bag to have automatic closing characteristics. Thus, if the forces tending to open the mouth of the bag are removed when the mouth has been opened, there is an immediate tendency for the two strips to move toward each other so that the mouth tends to remain normally closed.
It will be recalled from the preceding discussion that the preferred fastening means is of the frictional engagement snap-action type which requires nearly precise alignment of the two opposing handle portions of the unitary closure means to align accurately the mating portions of the snap fasteners before they can be snapped together. When the main bag element itself is of a thin-film plastic, it does not have sufiicient rigidity to accomplish this exact alignment automatically when the two opposing handle portions are brought together. Thus, the means by which exact alignment is obtained must reside in the construction of the unitary closure meansi'tself, More specifically, the formation of this unitary closure means so as to comprise two generally flat, overlying strips, joined at their respective ends by means which tends to hold them parallel, together with the resilience of the material used, tends to bring the mating portions of the snap fasteners into automatic and precise alignment whenever the two strips are brought together.
The foregoing advantages of the unitary closure means of the present invention are the result of a combination of factors employed in its construction and in the selection of the material as set forth above. It will be readily apparent that all these advantages could not possibly be obtained, for example, by the use of heavy cardboard, fabric, or the like, in the manufacture of the unitary closure means. For one thing, such materials cannot withstand the frequent fiexure that is required without rupture, nor do they have the necessary resilience which results in the automatic closure feature of the novel bag of this invention.
Referring to the drawings:
FIGURE 1 is a perspective View of the bag of the present invention including a unitary closure means;
FIGURE 2 is a perspective view of only the closure means of the invention; and
FIGURE 3 is a cross-sectional vie-w taken through the closure means of FIGURE 1 and showing in detail the fastening means for the open end of the bag.
In FIGURE 2, the handle and closure means 3 is shown as being of unitary construction, formed essentially of an endless loop of material having sharp creases or 180 bends at the ends 12 and 13 so that the opposite strips 1 and 2 thereof overlie each other. The sharp bends at 12, 13, are preferably formed in the member 3 while it is in a plastic state so that a definite set is taken as the material cools, whereby the 180 bends are permanently formed in the material.
To facilitate the manufacture and also to provide handle elements which lie precisely on top of each other when the bag is closed, the member 3 is formed so that the strips 1 and 2 thereof are essentially congruent. The central portions 4 and 5 are provided with apertures 6 and 7 therein which are in register and thus permit the insertion of the fingers of the person carrying the bag, thereby forming a handle.
As shown in greater detail in FIGURE 3, the fastening means may comprise projections or protuberances 8 and 10 on one member 2 which fit into recesses 9 and 11, respectively, in member 1, upon the application of force tending to draw the two strips 1 and 2 together.
FIGURE 3 further illustrates how the thin-film thermoplastic bag member 14 is fastened to the handle 3. This may be accomplished in any well-known manner such as by the use of cement, heating, or the like.
Both FIGURES 1 and 2 illustrate the shape assumed by the bag, especially the mouth end thereof, when one has unsnapped the two fasteners comprising the elements 811 and forcibly separated the strips 1 and 2 at their mid portions. Because of the sharp crease or fold permanently formed in the unitary closure means 3 at each of the ends 12 and 13 which tends to maintain the corresponding ends of strips 1 and 2 closely parallel near their end portions, and also because of the substantial resilience of the material, there is a tendency for the strips 1 and 2 to curve over substantially their entire length. However, it will be noted in both FIGURES l and 2 that there is substantially less curvature of these members occurring near their ends. In other words, deformation and the resulting stress which occur when the mouth of the bag is open tend to be distributed along the lengths of strips 1 and 2 which instead of being concentrated in the end portions 12 and 13 which would otherwise fail prematurely because of the relatively large amount of flexure taking place there each time the mouth of the bag is opened and closed.
By reason of the joining means employed to hold the strips 1 and 2 closely adjacent each other and closely parallel to each other at their respective ends and also by reason of the materials resilience, there is, in addition, a natural tendency for the strips 1 and 2 to be drawn together to thereby close the mouth of the bag when the strips are no longer forcibly separated as by pulling apart at its handle portions 4 and 5.
In addition to this automatic closure feature of the mouth of the bag, it will be readily apparent that there will always be exact alignment of snap fastener elements 8, 9 on the one hand, and 10, 11 on the other hand, to thereby facilitate engagement of these fasteners and a locking of the mouth of the bag. Consequently, fastener elements 8, 9 on the one hand, and 10, 11, on the other, are brought respectively opposite each other so that one need only exert pressure in the region of the closure elements 8, 9, 10 and 11 to snap together the opposing por tions 1 and 2 and thereby tightly close the bag.
The foregoing features are all in addition to that whereby the stresses resulting from opening of the mouth of the bag are prevented from being applied to the thin-film bag member 14 but are instead all borne by the unitary closure means 3.
It is fully appreciated that the prior art teaches the concept of having a bag which comprises a combination closure and handle means which is of a continuous loop construction. This type construction is shown, for example, in the patent to Verlin, No. 2,722,367. However, this patent teaches only that the upper loop material should be of paper stock, cardboard, or resin-impregnated fabric. Such materials do not have the property of being able to assume a sharp crease at the ends, and yet capa ble of being subjected to frequent fiexure as the bag is opened and closed many times, all without breaking or rupture of the closure member. In this connection, it should be noted that the prior art construction, if attempted to be adapted to the present invention, would be such that fieXure of member 3 would always occur at the respective ends 12 and 13, whereby rupture of the material at the folds must necessarily occur only after short usage. However, according to the presentinvention, opening and closure of the bags mouth tends to cause flexure along the length of members 1 and 2 and, not for the most part, in the immediate vicinity of the ends 12 and 13. Consequently, the stresses are very much more distributed and not concentrated in two small areas, i.e. the end portions 12 and 13. Also of significance is the fact that the prior art constructions using cardboard or the like would not provide the automatic closing feature described above.
Having described an improved plastic bag and particularly a novel handle and closure means therefor, it is to be understood that various modifications and alterations may be made to the specific form sho'wn without departing fro-m the scope of the invention.
What I claim is:
1. In a bag having front and back walls formed of a thin-film material the improvement Which comprises: unitary closure means attached to the walls of the bag in the plane of said walls at the mouth of the bag and having a total length substantially equal to the perimeter of the bag at its mouth; said closure means being formed of a resilient, elastic, non-brittle material, having a tensile strength substantially greater than that of the walls of said bag; said closure means comprising two generally congruent strips normally overlying each other and having registering finger openings therein to form a carrying handle for said bag; at least one fastener means comprising first and second functionally engaging elements respectively located on facing surfaces of said strips when in register for securing together said strips at a point between their adjoining ends; means joining said two strips at each end comprising an end portion which is integral with both said strips and normally maintaining the adjoining ends of said strips in parallel relationship; said resilience of said material together with said parallel relationship of the corresponding ends of said strips cooperating to maintain said strips normally closely parallel over their length thereby tending to maintain the mouth of said bag closed and automatically bringing said first and second engaging elements into alignment to thereby facilitate their engagement; said joining means together with said flexibility of said strips cooperating to cause said two strips to curve along substantially their entire length when said bag is opened but to curve substantially less near the respective ends of said strips Wherefor the resulting forces are distributed substantially along the length of said strips instead of being concentrated at the respective ends thereof.
2. The invention as defined in claim 1 in which said thin-film material and also the material of said closure means is of a thermoplastic material.
3. Closure means for a bag adapted to be attached to the front and back walls of said bag and comprising, a unitary member comprising two elongated closure strips each having a length substantially equalling the width of said front and back walls at the mouth of said bag, said strips having generally similar configuration and normally 25 spectively engaging elements on facing surfaces of said two strips when in registration, joining means comprising a part of said unitary member for joining said two strips in parallel relationship at each end, said unitary member being formed of a flexible resilient material, said joining means cooperating with the resilience of said unitary member to maintain said strips normally in close parallel relationship over their entire length thereby to tend to maintain the mouth of said bag closed, said overlying relationship of said strips and said joining means cooperating to bring said strips into exact regstration upon the closure of the mouth of said bag to thereby facilitate the engagement of said fastener means.
4. The closure means of claim 3 in which said unitary member is formed of a thermoplastic material.
References Cited by the Examiner UNITED STATES PATENTS 2,722,367 11/1955 Verlin 2 2.954
FOREIGN PATENTS 1,209,370 9/1959 France.
JOSEPH R. LECLAIR, Primary Examiner.
R. PESHOCK, Assistant Examiner.