DE2804012A1 - Bendable plastics drinking straw - is bent by axially compressing it to form transverse, annular, corrugations - Google Patents

Abstract

Plastics drinking straws which have corrugations lying in a plane perpendicular to the longitudinal axis of the drinking straw, comprise thin-walled plastics tubes. Corrugation is effected by simply axially compressing the tube thus giving rise to annular, highly uniform and evenly distributed, pleats. These corrugations, are opt. restricted to limited sections along the length of the straw. They can be thermally fixed by radiant heat or by contacting with a heated medium e.g. air.

Description

Designation: drinking straw ribbing process | File number: P 28 04 012.2 DESCRIPTION Title: Trinkhalmverrippungsverfshren Field of application: The invention relates to a method for producing ring-like ribs in the wall of thinner walls Plastic pipes to enable the pipes to kink, especially for the Use as a drinking straw.

Purpose: The ribbing applied in a 10 to 20 mm long zone allows the drinking straw to bend in this zone in such a way that the zone does the job of a pipe elbow.

The thus designed drinking straw has a more comfortable drinking from glass and Bottle and also an appealing visual impression.

State of the art with sites: Such drinking straws were found already on the market in the Federal Republic of Germany in 1974, but are from does not produce a domestic drinking straw manufacturer, but imports it. In and There is no registered process for producing straw ribbing abroad.

It is known that such plastic tubes are extruded (Plastics science for engineers, C.-M. von Meysenbug, 4th edition, Carl Hanser Verlag Munich, 1973 pages 82 to 85).

It is also known that these thermoplastic pipes by Vaguumformwrg (Kunststoffkunde für Ingenieure, C.-M, von Meysenbug, 4th edition, Carl Hanser Verlag Munich 1973 pages 97 to 98) and by cold forming, e.g.

Flanging, according to the processing of thin metal sheets Designation: straw ribbing process | Reference number: P 28 04 012.2 (specialist knowledge for metalworking Berufe, Europa-Behrmittel O.ll.G.Wuppertal-Barmen, Verlag Willing and Co. 33rd edition, Pages 189 to 190), deformed or

can be profiled.

Criticism of the prior art: the application of these methods to Production of the straw ribbing is very difficult, expensive and requires a lot of experience. For these reasons, the previous attempts to produce ribbed drinking straws have been unsuccessful domestically.

Task: The invention is based on the task of providing a simple, uncomplicated process for the industrial production of ribbed drinking straws create.

Solution: This object is achieved according to the invention in that the Ribbing by simply pushing the ax together axially, by means of a mandrel on the inside supported drinking straw without having to do anything else.

Another embodiment of the invention: the drinking straw shaped in this way maintains the folding function of the folds (which has the consequence that the drinking straw Bend into the shape of a pipe elbow almost any number of times in the area of the ribs or pull it apart) only by briefly thermally fixing the ribs.

Achievable Advantages: The advantages achieved with the invention exist especially in the fact that the straw ribbing method works safely, can be worked with significantly simpler factory eyes and the operation of Designation: drinking straw ribbing process file number: P 28 04 012.2 Pushing together the resulting ribbing, the prior art Appropriate procedure before packaging and transport is required falls as unproductive work step, since pushing together is already the main work step is.

Description of operations: Operation 1) Folding the first ring: The drinking straw is pushed onto a steel mandrel (Figure 1), the mandrel diameter and the inner diameter of the drinking straw should be dimensioned so that it can be pushed open of the drinking straw on the thorn with IIand is just possible. The closed one two-part clamping jaws ensures that the drinking straw is fixed and immovable to the Mandrel is pressed. The two-part clamping jaw has a 6.5 mm hole at the end a conical surface to influence the shape of the first ring, the two Parts of the clamping jaws are centered with cylindrical pins.

They are pressed together with the force F1. The two rubber jaws are compressed with the force F2, this causes the axial force component (Frictional force) Fr = F2 @ µ rubber-plastic is greater than the frictional force Fr 2 F2 a Plastic steel, due to the high coefficient of friction of rubber. µ = Mü = coefficient of friction as a result the application of the force F3 causes the rubber cheeks to axially over the drinking straw Move the bolt, which results in the formation (folding) of the first ring has (Figure 2) step 2) folding the remaining rings (e.g. nine more rings ), The two-part elbow jaw is now removed and a support ring is attached to its cell brought in front of the first ring (first fold). The support ring consists of only one Part, its hole may be up to 0.1mm larger than the outer diameter of the drinking straw. This has the consequence that the axial force F4 over the first fold in the drinking Designation: Drinking straw ribbing process file number: P 28 04 012.2 halm is initiated, this is necessary for the proper production of the further rings (folds). The rubber jaws remain in the same place as in step 1), unchanged and with the same clamping force (Figure 3 and Figure 4). The steel mandrel remains stand relative to the rubber jaws in this operation, this fact is for the process, however, is meaningless.

Work step 3) Fixing the rings (folds): So that the in work step 2) The folds that have arisen can be opened and folded almost as often as required Thickness (wall thickness) of the plastic material in the radii of the rings (folds ) be thinner than the rest of the wall thickness. The radii of the rings (folds) work thus similar to hinges. After work step 2), the support ring and rubber jaws are made removed, but the steel spike is still left in the drinking straw. For fixation If the drinking straw with the spike is placed a few cm apart (e.g.

2 cm) brought over a tea light (or candle) and while the drinking straw rotates, leave it there for a few seconds. In industrial manufacturing one would z.I3.

an electric heater, which completely covers the drinking straw in the fold area use it, in this case the drinking straw would not need to rotate.

The heating is caused by briefly becoming doughy (melting ) the plastic material of the radii of the rings (folds) that first as above required, the wall thickness of the material of the radii is reduced (reduced ) and secondly, it is fixed in the folded state. Set both points also presupposes that the tensions formed during the folding have been relieved ( Figure 5).

When pulling apart (pulling in axial direction) the drinking straw unfold all folds, due to the hinge effect there are also only a few Tensions Designation: Trinkhalmverrippungsveria @ ren file number: P 28 04 012.2 available. The highest tensions are during the folding of the bucket fold present, therefore the two less stressed states (unfolded , folded-t) stable states. A third stable state arises a, if the drinking straw is bent in the fold area (e.g. for practical drinking) becomes and the fold area becomes the pipe elbow. In this case the rings ( Folds) only folded in on part of the periphery of the drinking straw.

The fixation can also be done with a thinner mandrel diameter than the required for fixation of the Ihtrchmesser, or can be done without a mandrel.

Figure 6 shows the pulled apart drinking straw.

Materials used: drinking straw: polypropylene mandrel, clamping jaws, Support ring: St 37 was used in the tests.

Giimmibacken: In the trials of Jurde Buna S, with a Shore I hardness used by about 60.

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Claims (1)

Patent claim: The legal protection should focus on the method of manufacture of the ribbed drinking straws refer to the following two points: 1) By simple axial pushing together of a thin-walled plastic tube is formed With a suitable introduction of force, the ribbing described as a result of the formation of ring-like folds, which develop with great ease or regularity train in their dimensions 2) {so these folds ground the ribs thermally fixed (by the rays of a Narmeauelle or by one of the rays or the Xärmenuelle itself heated medium eg. Air) opens and closes the old one, therefore, pulling the ribs apart and pushing them together almost arbitrarily often possible. There are three stable layers in which the drinking straw is located or the ribbing does not move into another position by itself (without contact from the outside ) emotional. These layers are: 1) pushed together (folds closed) 2) pulled apart (Folds unfolded) whereby the case can be partially pulled apart here is 3) bending the ribbing (some of the folds or all of the folds are only on a small part of the circumference of the drinking straw, the rest of the larger part Part remains unfolded. The ribbing then has the function of a pipe bend