EP1240640B1 - Method for production of drawn seals - Google Patents

Description

The present invention relates to a method for manufacturing of pull-through seals according to the preamble of claim 1.

Traditionally, pull seals are made of plastic manufactured by spraying. For this purpose, forms in usually metal molds, manufactured, in which subsequently the plastic in liquid form under high pressure is injected and the pull-through seal in one operation is made in one piece.

Such a pull-through seal has a base body in construction with attached closure body and a protruding from the base body tongue leading away, Tip inserted through the closure body when in use can be. The tongue usually points Restraint in the form of knobs or teeth, which is the passage of the tongue through the closure body allow in one direction. In the opposite But direction is by arranged in the closure body Blocking agents that act on the tongue restraint act, a retraction of the tongue impossible. such Pull-through seals are so-called one-way means, i.e. you can usually only used once and the Closure can only be released by destruction.

The size in particular depends on the area of application the tongue and the type of closure body selected.

The problem now arises that when one is required long tongue the appropriate tool, respectively. the corresponding Form relatively large must, which on the one hand leads to high costs and on the other hand to problems regarding the complete and homogeneous Filling the form can lead, which in turn is expensive Manufacturing process conditional, which too an increase in the cost of manufacture and thus of the product to lead.

The object of the present invention was now to a process for the production of pull-through seals To find plastic that allows practically any To produce dimensions of tongues without additional effort.

According to the invention, this object is achieved by the method described in claim 1 defined procedures solved.

Preferred embodiments of the method according to the invention result from the further claims 2 to 8.

By making the tongue of the pull-through seal in the Extrusion processes can advantageously be practically any Dimensions, especially in length, can be achieved. Next in terms of strength after profiling and lengthen the tongue body higher Strength values than with conventional spraying produced sealing tongues achieved. Instead of manufacturing of many different molds for each one needed Dimensioning can be done with a single extrusion tool and the use of a standardized body practically all requirements for the pull-through seals a smaller one compared to the conventional method Effort to be covered.

Another advantage is the possibility of using it of polyethylene as plastic for the manufacture of the Pull-through seal, since the strength is achieved through the stretching process is increased by aligning the plastic molecules and practically the same values as with conventional pull-through seals made from polyamide at a much lower cost.

Fig. 1 schematisch die Prozessdarstellung der erfindungsgemässen Herstellungsverfahrens für eine Durchziehplombe;

Fig. 2 der Querschnitt des Profilstranges der Zunge nach dem Extrudieren;

Fig. 3 der Querschnitt des Profilstranges der zunge nach der Profilierung mittels eins Profilrades;

Fig. 4 der Querschnitt des Profilstranges der Zunge nach dem Streckvorgang; und

Fig. 5 die Aufsicht auf eine erfindungsgemäss hergestellte Durchziehplombe.

An embodiment of the present invention is explained in more detail below with reference to figures. Show it

1 schematically shows the process of the manufacturing method according to the invention for a pull-through seal;

2 shows the cross section of the profile strand of the tongue after extrusion.

Figure 3 shows the cross section of the profile strand of the tongue after profiling by means of a profile wheel.

Figure 4 shows the cross section of the profile strand of the tongue after the stretching process. and

5 shows the top view of a pull-through seal produced according to the invention.

The production process according to the invention is shown schematically in FIG a pull-through seal 1 made of plastic. In a first process group, the tongue of the Pull seal made by preferably a trapezoidal Profile 2 is extruded, which immediately after the extrusion is profiled. The cross section of the profile strand 2 is shown in FIG. 2.

The profiling is preferably carried out via a profiled Wheel 3, which is preferably on the short top of the extruded profile strand 2 is pressed on in a rolling manner. In order to a rack-shaped profile strand 4 is generated, as shown in Figure 3. The profile surveys 4 ' preferably have a regular distance A.

These two process steps can advantageously be continuous unlike the conventional one Pressure spraying process in molds, each for each piece must be done individually. This means, the extrusion process allows tongues of any length be produced by the profile strand 4 subsequently is cut to the required length.

This profile strand 4 then becomes a stretching process 5 supplied, which the length of the profile strand 4th preferably doubled. Again, this can be advantageous done continuously, or alternatively for those already Profile pieces cut to the required dimension can be applied individually. The stretching process 5 the profiled profile strand 4 leads on the one hand to a Alignment of the plastic molecules, which increases the strength. This can advantageously be polyethylene as a plastic be used, which is cheaper than that Polyamide conventionally used in the pressure spray process, but practically the same strength values due to the stretching how the polyamide achieved. This will be preferred by stretching the profile at a temperature of 60 ° C reached. Another of these procedures lies in that the material practically without tensile load Elongation breaks when the breaking limit is reached, which is an invisible Manipulation of the pull-through seal practically impossible.

On the other hand, especially the stretching tapered sections 4 '' of the profiled extruded section 4 stretched and thus created an end profile shape 6, which ideal with the resilient retaining means of the closure body the pull seal fit together. In Figure 4 the View of a section of such an end profile shape 6 shown, in which the profile elevations 6 'now preferably twice the distance 2A or more in comparison have with the profiled profile strand 4. So that will pulling through the closure body in one direction allows while retreating to the opposite Direction by engaging the restraint against the Profile edges of the tongue is impossible, like this for Pull-through seals are known.

The cut to the required length, finished profiled tongues 7 are now on the base body 8 of the pull-through seal 1 on the provided accordingly Spot sprayed. This makes it stable and tamper-proof Connection created. Another advantage this method enables the use of different colored material for the base body 8 and the tongue 7, what additional creative freedom with the Production of pull seals 1 results.

The base body 8 can, for example, in a conventional manner be produced by pressure spraying and thereby either in one piece with a closure body 9 be equipped, or this will be in an additional Process step similar to the tongue 7 also separately on the Base body sprayed on. This latter process step in turn preferably enables an increased design Freedom in the design of pull-through seals 1 by the closure body 9, for example, in several parts and especially not only from one material but from one Composition of different materials can exist. So can in particular a closure body 9 with a metal insert be used, which has an increased tensile strength and Tamper-evident. In Figure 5 is the supervision shown on a pull-through seal 1 produced in this way.

A pull-through seal 1 produced in this way has a very large high security against manipulation, since after manipulation, such as cutting the tongue 7, this Manipulation does not simply undo or invisible can be made. If preferably polyethylene is used an interface cannot simply pass through invisible bonding can be connected again. When using the material simply melts from heat and can not simply welded as a stable connection.

The manufacturing process presented can thus be universal for the production of pull seals 1 with different Tongue lengths and, if necessary, different closure bodies 9 are used and require only a minimal Number of tools. It is particularly advantageous that not for each different length of tongue required an own, special injection mold has to be manufactured and thus the procedure is based on the cost-effective and economical production of small quantities in special sizes suitable or designs. In addition, a cheaper one Plastic like polyethylene with undiminished Strength values of the pull-through seal 1 are used, than this in conventional injection molding due to the use of polyamide.

Claims (8)

1. A method for the production of drawn seals (1) made of plastic material with a base body (8) having a sealing body (9) and a tongue (7) projecting from the base body (8), characterized in that the tongue (7) is manufactured by extrusion and subsequent profiling and following lengthening in longitudinal direction of the tongue profile, and in that thereafter the finished tongue profile (7) is connected to the base body (8) by injection molding.
2. The method according to claim 1, wherein the tongue (7) is extruded with a rectangular or trapezoidally-shaped cross section (2).
3. The method according to claim 1 or 2, wherein the extruder profile (2) is profiled, preferably only on one side, directly after the extrusion by means of a profiled wheel (3).
4. The method according to one of the claims 1 to 3, wherein the profiled tongue profile (4) is lengthened by the factor two or greater in its length.
5. The method according to one of the claims 1 to 4, wherein the profiled tongue profile (4) is cooled off prior to the lengthening (5) to under the heat distortion temperature, preferably to approximately 60°C.
6. The method according to one of the claims 1 to 5, wherein the sealing body (9) is injection molded onto the base body (8).
7. The method according to claim 6, wherein a multi-part sealing body (9), preferably made of various materials, is injection molded.
8. The method according to one of the claims 1 to 7, wherein polyethylene is used as the material.

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