One-piece hinged snap-on cap

DESCRIPTION

The present invention relates to a spring-shaped flap of a single piece of plastic, with a bottom and a cap, so that both pieces have a wrapping wall respectively. In the closed position of the lid, these wrapping walls overlap vertically in a congruent manner. The lower part is joined with the end by means of at least one laminar hinge and two strap flanges arranged on both sides of the laminar hinge, which are stretched in the closed position of the lid.

Solution proposals have been made known in which the elastic elements or the hinge pieces of a spring hinge are set in an adjacent position where possible, in DEC-589 647 and DE-A 30 26 436. The US follows -A 3 964 609 the elastic element is constructed even separately, being introduced in a recess parallel to the outer wall of the container.

A spring flap of the aforementioned type is known, for example by EPA-0 147 423. The strap flanges of the known solution are normally fixed to molten projections of a piece that overlap the outer envelope surface and are they place in a plane that cuts like a secant the plastic lid. These covers have given the best results for their operation, consistency and closing power. They have been blamed on the market especially for its static appearance, as well as the ability to handle the lids at filling stations. Outgoing strap flanges are occasionally cause for clogging in transport routes.

A solution to the double problem mentioned is that presented in EP-A-056 469. In this case, instead of the strapping flanges, there are intermediate elements arranged laterally in the articulation of the laminar hinge, which as such circumstance and by its constitution have thick walls, and are joined by laminar hinges to the bottom and to the otapáon finish. The precise force for the spring effect is not obtained in this case from the longitudinal dilatation of the intermediate elements, but from the power of recovery of the intermediate elements, in a bulged manner. The tensile forces that occur when opening and closing the lid run through the laminar hinge with which the intermediate elements join the auction and the bottom. The laminar hinge that forms the axis of rotation is highlighted when the lid is opened. Although the crushing of a laminar hinge does not present difficulties, the efforts of traction on a laminar hinge represent a great risk. If the traction efforts run exactly in the direction of vertical development to the axis of the laminar hinge, as required by EP-A-056 469, the correct action of the force mentioned above is not guaranteed. The result is that on the sides of the laminar hinge there is an overdilatacioán with notching effect and the laminar flaps are broken.

The thickness of the material in the area of ​​a laminar hinge is only 0.1-0.2 mm. This forces during the injection process an orientation of the direction of macromolecules in the area of ​​the lamellar hinge. In areas where macromolecules have a direction of direction, they bear only reduced forces transversely to the sense of development, as they occur in the version according to the present invention. On the contrary the thickness of material in a strap flange of about 0.5 - 0.8 mm, is 4 to 5 times greater. In this case, an orientation of the macromolecules is not given during the injection process. The sense of action of the forces on the strapping flanges is therefore invaluable. In addition, the size of the openings of the injection mold through which the material from the lower part always passes to the finish determines the injection rate.

Based on the previous knowledge, the applicant has achieved after complicated measurements and experiences, and the purpose has been raised, of constructing a plastic flap of the type mentioned at the beginning, with which to avoid the problems of the aforementioned watermelon.

This problem is solved by the invention with a plastic spring hinged lid, of the characteristics set forth in the significant part of claim 1.

The drawings show an example of the realization of the object of the invention, which is explained according to the following description:

Figure 1 is a view of the spring-like flapper lid at approximately natural size, on a tube viewed from the front;

Figure 2 is a side view and

Figure 3 is a view behind.

Figure 4 is a view of the same cap on a larger scale in the open full injection position, in side view and

Figure 5 is a top view, so that the auction can be seen from the inside.

Figure 6 shows a vertical section through the axis of rotation of the spring hinge along the line BB of Figure 5 and

Figure 7, a partial section along the CC line of Figure 5.

Figure 8, a- d shows several ways of sectioning the strapping flanges.

In the drawing, the lower part of the spring flap lid of a piece with -1- and the upper part attached to that with -2 is designated. The spring hinge is integrated into a lid in the form shown. But it is clear that the spring hinge according to the invention can also be integrated into a block that includes the characteristics of the main concept of claim 1. In this case, one-piece molded plastic boxes and boxes are especially included. The exemplary embodiment represented according to the principle follows the invention is a cover in which the cover part -1- is secured to a tube T. The upper part -2 is in this case a cap or cap. The two parts -1- and -2- of the lid are joined together by means of a conventional laminar hinge -3, which protrudes slightly from the surrounding contour wall. The enveloping wall -4 of the lower part -1- and the enveloping wall -5 of the end and of the upper part -2- overlap vertically. In front of the laminar flap has been arranged in the

017 801 upper and lower parts a recess -8- that facilitates the opening of the lid. To the left and right of the laminar hinge -3 only the two strapping flanges -6- can be seen initially. They have been integrated into the enveloping surfaces -4- and -5- so that only the lateral limitations -7- are appreciated. The outer surfaces of the strapping flanges -6- align without slight deviations with the wrapping surfaces of the upper and lower parts -1-, -2-.

In Fig. 4, the same example of embodiment of the spring hinge in the lid is shown according to Figs. 1-3, in the fully open position and on a larger scale. The lower part -1- has a cover surface -9- that rises above the plane of separation E of the upper and lower parts -1-, -2- and has a cionic peak -10- that runs upwards. The strap flanges -6- are distended in this position, and form an arc. As in this case the strapping flanges are located on the periphery of the bulging enveloping surfaces, the strapping flanges are arched in the area near the laminar hinge, more intensely than the areas far away from the lamellar hinge. That is why he saw the strap flange in side view with a double rope. Also in the view following Figure 5, which shows a detail of the cover according to Figure 4, it can be seen that the radius of the strap flanges -6- curved in this position of the hinge is smaller near the laminar flap -3-. This is depicted in detail in Figure 7, with a section along the CC line in Figure 5.

In this representation, figure 5 follows, in which the upper part or the top is shown below and inside, and the lower part above, the alveoli -11- in which the strapping flanges are housed are also appreciated. The alveoli of the top and the upper part -2- do not cross the surrounding wall -5-, but leave a minimum wall thickness necessary, so that in the closed position of the cover, the upper and lower parts overlap in all the contour of the enveloping walls. This is of great importance, because as is well known, the pliastic pieces are very esthetically loaded. As a result, the dust particles, if the lid is not perfectly closed, are magnetically attracted to the interior through possible indentations, resulting in a perceptible fouling.

The surfaces of the base of the alveoli -11 can run parallel or inclined with respect to the plane of separation E. Naturally then the strapping flanges -6-, as far as they move away from the axis of rotation, specifically the laminar hinge -3-, both Long would be. Consequently, the bases of the alveoli run from the far end to the laminar hinge and from the lower to the upper end and closer to the laminar hinge. In Figure 6, a cut through the lid open vertically to the laminar hinge, the bases of the alveoli are marked with dots, although in this view, they are naturally invisible.

An essential characteristic between the strapping flanges such as those used in this invention, and the intermediate elements following the current technical level, is that the strapping flanges -6-, from the point of support in the alveoli -11- and in their entire length has at least approximately the same sectional surface. Certainly the flanges can be rounded or thickened at the top, to prevent a notching effect. But in the area that leads to the necessary elastic longitudinal expansion, the sectional surface remains the same, except for inaccuracies.

The section form of the strapping flanges -6 can be very variable. This is shown in the examples in figures 8a - d. Then the outer surface can be adapted exactly to the contour of the surrounding wall, but the inner surface has to be straight (Figure 8a).

But next to the purely rectangular shape, as can be seen in Figure 6, a convex shape on all sides would also be possible, for example, an ellipse as in Figure 8b. If the flanges are configured in the form of u as in figure 8c, an energetic spring effect of the hinge is obtained. The subdivision of the flanges is strapped into several partial flanges as indicated in Figure 8d, allowing a better adaptation of the spring hinge following the invention to relatively complex configuration forms of the mutually joined parts by means of the hinge. If the spring hinge follows the invention, it is made in the form of a square or polygonal box or boat, my laminar hinges can be provided in the straight part, all of them located on a straight line. Then the hinge can be used in multiple ways according to the invention.

017 801