U.S. patent application number 10/209013 was filed with the patent office on 2002-12-12 for tube shoulder and method for its manufacture.
This patent application is currently assigned to FOBOHA GmbH. Invention is credited to Armbruster, Rainer.
Application Number | 20020185778 10/209013 |
Document ID | / |
Family ID | 8237579 |
Filed Date | 2002-12-12 |
United States Patent
Application |
20020185778 |
Kind Code |
A1 |
Armbruster, Rainer |
December 12, 2002 |
Tube shoulder and method for its manufacture
Abstract
A multilayer tube shoulder and method for manufacture wherein a
first material component is injected into a cavity (22) and then
removed from the cavity on a support (12) while in a partly-plastic
state. Thereafter, following insertion of the first material
component into a second cavity (23), a second material component is
injected around the first material component, and thereby leads to
a positive connection between the first and second material
components.
Inventors: |
Armbruster, Rainer;
(Wolfach, DE) |
Correspondence
Address: |
RANKIN, HILL, PORTER & CLARK, LLP
700 HUNTINGTON BUILDING
925 EUCLID AVENUE, SUITE 700
CLEVELAND
OH
44115-1405
US
|
Assignee: |
FOBOHA GmbH
Haslach
DE
|
Family ID: |
8237579 |
Appl. No.: |
10/209013 |
Filed: |
July 31, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10209013 |
Jul 31, 2002 |
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09505815 |
Feb 17, 2000 |
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6464921 |
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Current U.S.
Class: |
264/255 ;
264/250; 425/112; 425/126.1; 425/575; 425/588 |
Current CPC
Class: |
B29L 2009/00 20130101;
B29L 2023/20 20130101; B65D 35/12 20130101; B29C 45/16 20130101;
B29C 45/1615 20130101 |
Class at
Publication: |
264/255 ;
264/250; 425/112; 425/126.1; 425/588; 425/575 |
International
Class: |
B29C 045/16 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 1999 |
EP |
99103183.2 |
Claims
What is claimed is:
1. A mold (10) for manufacturing a multi-layer tube shoulder,
wherein said mold defines a first cavity and a second cavity, and
said multi-layer tube shoulder is formed by the steps of: injecting
a first material component into a first cavity (22); using a
support (12) to remove said first material component from said
first cavity in a partially plastic state; inserting said partially
plastic first material component into a second cavity (23), said
second cavity having, after receipt of said first material
component, a free space extending such that at least one face (4,5)
of said first material component is exposed; injecting a second
material component into said second cavity and onto said first
material component, said at least one face being engaged by said
second material component and serving as a mechanical stop for the
first material component with respect to the second material
component, so that there is a positive connection between the first
and second material; wherein said mold comprises a base body (11)
and a core (12.1, 12.2), wherein at least one of the base body (11)
and the core (12.1, 12.2) are closed with a media selected from the
group consisting of gaseous and liquid media.
2. A tube shoulder, said tube shoulder being made according to the
following steps: said multi-layer tube shoulder is formed by the
steps of: injecting a first material component into a first cavity
(22); using a support (12) to remove said first material component
from said first cavity in a partially plastic state; inserting said
partially plastic first material component into a second cavity
(23), said second cavity having, after receipt of said first
material component, a free space extending such that at least one
face (4,5) of said first material component is exposed; injecting a
second material component into said second cavity and onto said
first material component, said at least one face being engaged by
said second material component and serving as a mechanical stop for
the first material component with respect to the second material
component, so that there is a positive connection between the first
and second material; and wherein said at least one face (4, 5) of a
barrier layer (3) serves as a mechanical stop for an outer layer
(2) and thereby provides a positive connection between the barrier
layer (3) and the outer layer (2).
3. The tube shoulder according to claim 2, wherein said at least
one face (4, 5) is annular.
4. The tube shoulder according to claim 4, wherein an outlet port
(6) has a non-circular cross-section so as to impress a pattern on
the filled material passing through said outlet port, said pattern
corresponding to the non-circular cross-section of said outlet
port.
5. The tube shoulder according to claim 4, wherein the barrier
layer (3) is a first color and the outer layer is a second color,
said first color being different than said second color.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a multilayer tube shoulder
for a tube and to a method for the manufacture of such tube
shoulders according to the preambles of the independent claims.
[0002] The prior art discloses numerous tube shoulders for tubes.
Currently, such tube shoulders are almost exclusively made from
thermoplastic material by injection molding and are then welded to
the tubular tube body in a further operation.
[0003] Certain plastics, such as polyethylene (PE), have a
considerable permeability for oxygen, carbon dioxide and
odorous/aromatizing substances. In the case of tube shoulders made
from these materials, undesired substances diffuse or pass out of
the tube into the environment or pass from the environment into the
tube, which is prejudicial to the substance introduced into the
tube. In order to prevent this harmful permeability, tube shoulders
generally have a two-layer structure, comprising an outer, shaping
layer and an inner barrier layer.
[0004] The material generally used for the shaping layer is
polyethylene (PE), while the barrier layer material is polyethylene
rerephthalate (PET). The fact that these materials do not adhere to
one another constitutes one of the main problems in the rational,
economic manufacture of tube shoulders.
[0005] The use of multilayer tube shoulders of PE and PET has been
adopted. Thus, the prior art discloses numerous attempts to
rationally and economically manufacture known, multilayer tube
shoulders. U.S. Pat. No. 4,185,757 discloses one such attempt.
However, none of the known solutions is completely satisfactory.
Since tube shoulders are mass produced articles, the price is
mainly determined by two factors: cost/material consumption and
cycle time for manufacture. The tube shoulders known from the prior
art on the one hand have an excessive material consumption, which
has a negative effect on the consumption of resources, and
therefore costs and environmental compatibility. On the other hand
they cannot be manufactured rationally, because they require long
cycle times. In fact, certain tube shoulders even require several
injection molds and several operations, which amounts to a poor
utilization of the machines and molds.
[0006] The problem of non-mutually adhering materials has in the
prior art led to inefficient or even impracticable solutions. As
e.g. in U.S. Pat. No. 4,185,757, these are based on filigree
undercuts and keys or wedges, which are intended to bring about a
positive connection between the inner barrier layer and the outer,
shaping layer of a tube shoulder. These undercuts and keys e.g.
comprise mutually corresponding grooves and ribs, which are
generally made at right angles to the symmetry axis of the tube
shoulder and are so constructed that they must be forcibly
demolded.
[0007] Another multilayer tube shoulder is described in European
patent application EP-130 239. This application teaches a
multilayer tube shoulder having an inner barrier layer adhering by
friction to an outer, shaping layer. This arrangement is
unsatisfactory for various reasons. Firstly, the two layers must be
combined in a separate operation. Secondly, there is no reliable
hold between the two parts. Thirdly, the parts require increased
manufacturing precision, which, inter alia, takes into account the
differing shrinkage behavior of the materials.
[0008] The parts of the above-described tube shoulders can
generally only be further processed after complete cooling. It is
also necessary to manually join the individual parts in a separate
operation. Thus, the prior art arrangements lead to the
manufacturing process for the corresponding tube shoulders being
directly and completely decelerated.
SUMMARY OF THE INVENTION
[0009] The present invention is directed toward a tube shoulder and
method for making a tube shoulder that avoids the disadvantages
discussed in conjunction with the aforementioned prior art. On the
one hand, by means of the present invention, drastic material
reductions are possible and, on the other hand, the manufacturing
time is greatly reduced and optimized, leading to a better
utilization of the invested resources.
[0010] Unlike in the prior art, which is generally based on a
forced demolding (removal from the mold) of cooled parts, in the
present invention there is no need to wait until the material of
the first component has cooled. Instead, further processing takes
place when the first part is in the uncured state. Accordingly, the
present method provides considerable time saving while greatly
reducing material consumption because the layers of the tube
shoulder disclosed here, unlike with the conventional tube
shoulders, are made significantly thinner.
[0011] In further accordance with the present invention, further
processing the first component of the tube shoulder can be done
before the material has completely cured. Therefore, the present
production-optimized design of the tube shoulder does not, unlike
the known designs, constrain the production cycles. Undercuts or
filigree keys, which are difficult to remove from the mold or which
must even be forcibly de-molded, are not needed in the present
ivnetion. Rather, the inventive design utilizes generously
dimensioned contact faces between the individual parts of the tube
shoulder that are arranged so that no forced de-molding is
necessary and, therefore, leads to a very simple construction of
the injection mold. The design is also optimized such that material
shrinkage has no negative effect on manufacturing precision.
[0012] The present invention makes it possible, for the first time,
for a first material component to be injected in a first cavity of
an injection mold and to remove said first material component,
before the material has cured or completely hardened, from the
first cavity. Then, after release, a second component of another
material is injected around the first material, either in a second
cavity of the first injection mold or a second injection mold, so
as to obtain a strong mechanical connection between the first and
second material components.
[0013] The first material component in the first cavity is injected
on a support, which is designed to transport or convey partly
plastic material. Following injection of the first phase, the
support with the partly plastic material of the first component is
removed from the first cavity and introduced into the second
cavity. The material of the second component is injected and
positively joined to the first component. Prior to the injection of
the material of the second component, there is a release of the
material of the first component. This is a mechanical process
wherein, by means of a slider or a functionally equivalent element,
a certain area or surface of the first material component is freed,
so that the material of the second component in this area engages
in undercutting manner around the material of the first component
following the second injection process. As a result of the thus
formed mechanical stop, a positive connection is obtained between
the first material component and the second material component.
This release preferably takes place in a very large-area
manner.
[0014] Compared with the prior art the invention has two vital
advantages. On the one hand the material consumption of a two-layer
tube shoulder is massively reduced and, on the other hand, the
cycle time during manufacture is drastically decreased.
[0015] The present invention is also suitable for integrally
joining a tube body to the tube shoulder in a first step. This tube
body can be supplied as an extraneous part from the outside to the
processing operation. This additional step advantageously takes
place in a further cavity or is combined with one of the steps in
which the first or second material component is produced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The invention is described in greater detail hereinafter
relative to a preferred embodiment and the attached drawings,
wherein show:
[0017] FIG. 1 diagrammatically shows a preferred embodiment of a
tube shoulder in a perspective sectional view.
[0018] FIG. 2 diagrammatically shows a sequence of a tube shoulder
manufacturing process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] FIG. 1 shows a preferred embodiment of a tube shoulder 1 in
a perspective sectional view. The tube shoulder 1 comprises an
outer layer 2 and an inner barrier layer 3. Preferably the outer
layer 2 is of polyethylene (PE) and the barrier layer 3 of
polyethylene terephthalate (PET). The outer layer 2 is primarily
used for shaping the tube shoulder 1 and the barrier layer 3 serves
to seal the tube shoulder 1. The two materials of the outer layer 2
and barrier layer 3 will typically not melt, fuse, or bond with one
another. In order, despite this, to bring about a mechanical
connection, the outer layer 2 engages, or extends around, the
barrier layer 3, here at a lower face 4 and an upper face 5, so
that a large-area, positive connection is formed between the outer
layer 2 and the barrier layer 3. The inner layer is essentially
captured by the outer layer. The use of the method described
relative to FIG. 2 is made possible by the represented embodiment
of the tube shoulder 1 as a result of the inventive construction,
which deliberately avoids small undercuts and the like.
[0020] As a result of the inventive construction of the tube
shoulder 1, in which all the mechanical connections between the
outer layer 2 and barrier layer 3 are in large-area form, it is
possible to release the barrier layer in a mold 10 while the
material of said barrier layer 3 is still partly plastic. With
filigree or difficultly demoldable undercuts (e.g. undercuts which
must be forcibly demolded) this is not possible. The presently
disclosed invention is therefore based on a design of tube
shoulders permitting an optimum, large-area and unforced demolding,
without undercuts. The individual steps of the manufacturing
process are diagrammatically represented in FIGS. 2a) and 2b).
[0021] FIG. 2a) diagrammatically shows a sectional representation
through an injection mold 10 for the manufacture of the tube
shoulder 1 shown in FIG. 1. The injection mold 10 here comprises a
base body 11, which has two openings 20 and 21. Two, here
identical, rotationally symmetrical cores 12.1 and 12.2 and two
identical, annular release elements 14.1 and 14.2 engage from below
and in sealing manner in the openings 20 and 21, so as to form a
first cavity 22 and a second cavity 23. The first cavity 22
corresponds to the negative of a barrier layer 3 according to FIG.
1. The second cavity 23 corresponds to the negative of a barrier
layer 3 and an outer layer 2.
[0022] By means of a first runner or port 25 molten plastic of a
first material component, preferably PET, is injected into the
first cavity 22, so as to form a barrier layer 3 according to
[0023] FIG. 1. Before the plastic material of the barrier layer 3
has cured, the core 12, release element 14 and partly plastic
barrier layer 3 are drawn out of the opening 20. This process is
illustrated by an arrow 30.
[0024] As shown in FIG. 2b), subsequently the release element 14 is
so displaced (arrow 37), that there is a release of a lower surface
4 of the barrier layer 3. The core 12, release element 14 and
barrier layer 3 are subsequently sealingly inserted into the second
opening 21 of the injection mold 10 (FIG. 2a). This is
diagrammatically represented by an arrow 31. By means of a second
runner or port 26, a second material component is injected around
the released barrier layer 3 formed by the first material component
that a strong, mechanical connection is formed. At least one face,
preferably an annular face 4, 5 (cf. FIG. 1), serves as a
mechanical stop. The second material component forms an outer layer
2 according to FIG. 1.
[0025] The entire sequence is represented here in a highly
diagrammatic manner and is, in practice, advantageously
incorporated into a reversing mold with typically two cavities 20
and two cores 14.1 and 14.2. The two cores 14.1 and 14.2 are
simultaneously used. As a result of the tube shoulder design
according to the invention and the resulting unforced release of
the first material component in a partly plastic state, compared
with conventional tube shoulders, it is possible to achieve a
massive reduction of cycle times and material consumption. Also,
the barrier layer can be made very thin, because the core 14 acts
as a shaping support, thereby saving material costs.
[0026] At the end of a manufacturing cycle the release element 14
additionally serves as an ejection aid for the finished tube
shoulder 1.
[0027] To achieve a better sealing of the cavities 22 and 23, the
faces of the release elements 14.1, 14.2 and the cavities 22, 23,
which are in functional combination with one another, are
advantageously conically constructed.
[0028] Optionally, the core 14 and mold 1 may be cooled to further
control and speed the manufacturing process. Advantageously gas or
liquid cooling systems are used.
[0029] For aesthetic reasons it is possible to use differently
colored or transparent plastics, in order to achieve special
optical effects. This can, for example, be advantageous if the
barrier layer 3 is so positioned in the vicinity of an outlet port
6 (cf. FIG. 1) that it is visible from the outside for the user.
The outlet port 6 can also have a non-circular cross-section, so
that a pattern can be impressed on the filled material passing
out.
* * * * *