Note: Descriptions are shown in the official language in which they were submitted.
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HOLLOW GAS~ET WELDER
Backaround of ~he Invention
Field of the Invention
This invention relates generally to gasket welders and
more particularly to a gasket welder wherein a vacuum is
applied to the outer surface of the gasket, thereby
allowing the gasket to retain its original shape while
being welded to another gasket.
Description of the Prior Art
In various industries, there has always been the need
to weld two plastic parts together to form a single article
of manufacture. When the two thin walled parts to be
joined are flexible, there is the problem of maintaining
the profile of the parts, especially if they are hollow,
while they are being welded.
In the door and window industry, this problem has
recently become more acute. With the higher demand for
lncreased performance, it has been necessary to upgrade the
quality of weatherstripplng available. One type of
weatherstripping commonly used for doors and windows is a
TPE ~thermal plastic elastomer) weatherstrip which has a
hollow portion. In addition, a variety of weatherstrip
materials are utilized, such as PVC. The hollow portion i8
advantageous for many purposes, but it does raise the
problem of how to effectively join two pieces of
weatherstripping having the hollow profile. -During the
manufacturing process, when the two weatherstrips are
joined, quite often the weatherstripping is deformed during
the manufacturing operation and a less than perfect joint
is formed. This creates a potential for air or water
leakage around the improperly formed joint.
Many different welding machines have been used to join
such weatherstrips having a hollow, flexible construction.
One such machine is the DS four-point seal welding machine
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ADS-4 by Dieter Schuster GmbH. Such a weldinq machine is
able to weld four corners of a frame at one time, thereby
providing for a completed gasket in one operation.
However, such a welding machine does not allow for the
consistent high quality welding of a gasket having a thin
wall, flexible or hollow construction.
The present invention provides for a new jig which may
be used with such welding machines to overcome the problems
associated with the prior art and provide for a means of
maintaining the profile of the weatherstripping material
while it is being welded.
Summarv of the Invention
The invention is a jig for holding and positioning
flexible hollow articles. The jig includes a platen having
a bottom surface and a die having a top surface. When the
bottom surface i9 positioned proximate the top surface,
they form a cavity sized and configured to accept a
flexible hollow article. Either the platen or die has
formed therein a passageway which is in fluid communication
with the cavity. The passageway allows for a vacuum to be
applied to the outsLde surface of the article while in the
cavity, whereby the shape of the hollow article is
maintained.
~he invention is also a jig for holding and
cooperatively positioning a first flexible hollow article
or connecting to a second flexible hollow article. The
~ig has an upper platen assembly having first and second
platens each with a bottom surface and a lower die assembly
having first and second die, each having an upper surface.
The first and second die each have a cavity formed therein.
The cavity of the first die is sized and configured to
accept a irst 1exible hollow article and the cavity of
the second die is sized and configured to accept a second
flexible hollow article. The top surfaces, when positioned
proximate the bottom surfaces, hold the articles in the
cavities in position for manipulation and to cooperatively
connect the articles to each other. Either the first
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platen or first die has formed therein a passageway which
is in fluid communication with the cavity of the first die,
whereby a vacuum may be applied to the outside surface of
the articles while in the cavity, whereby the shape of the
hollow articles are maintained. The invention may also
include a welding machine which incorporates the jig.
Still further, the invention is a method for
cooperatively connecting a first flexible hollow article to
a second flexible hollow article. The method includes the
steps of placing a first flexible hollow article in a jig
and also placing a second flexible hollow article in the
jig. The jig is then positioned to place the first and
second articles in a working position and applying a
vacuum, through a passageway in the jig, to the articles to
maintain the profiles of the articles while the articles
are being cooperatively connected to each other.
Brief Description of the Drawinqs
Fig. 1 is a perspective view of a hollow gasket welder
embodying the present invention;
Fig. 2 is an enlarged perspective view of one of the
dies util~zed in the welder shown in Fig. 1.
Fig. 3 is a top plan view of a portion of the die
shown in Fig. 2.
Fiq. 4 ig a cross-sectional view taken generally along
the lines 4-4 of Fig. 3;
Figs. 5a through 5e are diagrammatical representations
of various steps that are taken throughout the welding
process.
Detailed Description of the Invention
Referring to the drawings, wherein like numbers
represent like parts throughout the several views, t~ere is
generally disclosed at 10 a hollow gasket welder. The
gasket welder 10, with the exception of the modified jig
assembly and vacuum means, is well known ln the art. A
brief description of the gasket welder will be given for
the purposes of better understanding the present invention.
However, it is understood that such gasket welders, with
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the exception of the modified jig assembly and vacuum
means, are well known in the art. As stated in the
description of the prior art, the Dieter Schuster GmbH
welder is one such example. The welder 10 has a base 11 on
which a stationary tabletop 12 is mounted by a plurality of
bolts 13 or other suitable means. Support blocks 14 are
mounted on the base 11 and rods 15 are cooperatively
connected thereto by suitably mounting them in apertures in
the mounting block 14. 8earings 16 are mounted on the rods
15 and a moveable tabletop 17 is mounted on the bearings.
An air cylinder 90 is mounted in support block 90a. The
air cylinder 90 is cooperatively connected by means not
shown, but well known in the art, to tabletop 17 so that
activation of the air cylinder 90 causes movement of the
tabletop 17. A guard plate 18 is mounted to the stationary
tabletop 12 and has an opening in which the moveable
tabletop 17 is configured to move laterally therein. A
first vertical support member assembly 19 is cooperatively
connected to the moveable tabletop 17 and a second vertical
support member assembly 20 is cooperatively connected to
the stationary tabletop 12. A first vertical pneumatic
cylinder 21 is cooperatively mounted to the first vertical
support member assembly 19 by appropriate means and a
second vertical pneumatic cylinder 22 is appropriately
mounted to the second vertical support assembly 20 by
appropriate means. Pneumatic control lines 21a and 21b are
cooperatively connected at one end to the pneumatic
cylinder 21 and to a pneumatic source at their other end.
Similarly, pneumatic lines 22a and 22b are cooperatively
connected to the second pneumatic cylinder 22 at one end
and to the pneumatic source at their other end. A first
support arm 23 is cooperatively connected to the first
pneumatic cylinder 21 and a second support arm 24 is
cooperatively connected to the second pneumatic cylinder
22. The movement of the cylinders 15, 21 and 22 are
appropriately controlled by a control panel 25 having
display gauges 26. As shown diagrammatically in Figs. 5a
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through 5e, the welder 10 also has a heating element 27 and
a stop element 28. The elements 27 and 28 are hidden from
view when viewed in Fig. 1. However, as previously
indicated, the welder, as described in the foregoing
paragraphs, is well known in the art.
An upper platen assembly 29 includes a first platen 30
and a second platen 31. The platens 30 an 31 are separate
and both have rectangular cross sections. The first platen
30a has a bottom surface 50 and the second platen 31 has a
bottom surface 51. A lower die assembly includes a first
die 32 and a second die 33. The dies 32 and 33 are also
rectangular in cross section. The die 32 has a top surface
52 and the second die 33 has a top surface 53. The first
platen has an inside surface 56 and the sécond platen has
an inside surface 54. The first die 32 has an inside
surface 57 and the second die 33 has an inside surface 55.
As more clearly shown in Fig. 2, a plurality of
cavities 40 through 43 are formed in the first die 32. The
cavities are at a 45 degree angle to the longitudinal axis
of the die. Similar cavities are formed in the die 33 and
are also at a 45 angle to the longitudinal a~is of die 33.
Therefore,~ as will be more fully described hereafter, the
cavities, when brought together, will form a 90 angle.
The configuration of the cavities 40 through 43 will depend
upon the shape of the article to be welded. The cavities
are formed to support the outer proile of the article.
Articles 60, 61, 62 and 63 all have the configuration as
clearly shown in Figs. 2 and 4. The articles are all
similar and accordingly a detailed description of only
article 60 will be given. The article 60 has two top
planar surfaces 60a and 60b, with the surface 60b being
slightly lower than the surface 60a. The top surface 60b
forms a portion of the flange section of the article 60
which comprises a solid material. The top surface 60a has
a cavity formed underneath it and a lower surface 60c,
thereby forming a hollow portion of the article. The
article 60, and the other articles 61 through 63 may of
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course take on any suitable shape or configuration.
However, the article 60, as shown, is that of a
weatherstrip used in a door sold by Andersen Corporation,
Bayport, Minnesota. Article 60 is referred to in this
S specification as a hollow article because of the cavity
formed between the surfaces 60a and 60c. The welding of
such hollow articles gives rise to special problems in the
industry. These special problems are caused because of the
deflection between the surfaces 60a and 60c during welding.
It is understood that when the term hollow article is used,
this may also refer to an article which is a solid, but
which have outer surfaces which are easily deformed or
compressed during the welding operation.
The foregoing description of the upper platen assembly
and lower die assembly as presently described is also well
known in the art. It is of course understood that the
cavities formed in the dies 32 and 33 take the shape of the
outer profile of the article to be welded. It is well
known in the art to adjust this configuration to match that
of the article.
With the foregoing still describing what is well known
in the art, it has been found that such a welder does not
adeguately weld flexible plastic articles to each other.
The pressures exerted during welding cause the surface 60a
and 60c to deflect, thereby giving an improper weld to the
matching article in the second die. To overcome this
problem, applicant has developed a means of applying vacuum
to the article being welded, thereby maintaining the shape
of the article during the welding process. Longitudinal
passageways, in the shape of cylindrical bores, are formed
in the first and second platens and first and second dies.
In the first platen 30, a longitudinal bore 30a is formed;
in the second platen 31 a longitudinal bore 31a is formed;
in the first die 32 a longitudinal bore 32a is formed; and
in the second die 33, a longitudinal bore 33 is formed.
The bores extend the entire length of the platens and dies.
At the front end of the platens and dies, as can be seen in
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Fig. 1, a suitable cap or plug is secured into the
respective bores so that there will be no air leakage.
Alternately, it is understood that the bores could simply
not extend outside of the platens and dies so that a cap or
plug would not be necessary to maintain the airtight
connection. The other end of the bores are cooperatively
connected to a vacuum source. A suitable fitting 77 is
cooperatively connected to the bore 30a and a fitting 78 is
cooperatively connected to the bore 32a. A hose 75 is
cooperatively connected to the fitting 78 and a hose 77 is
cooperatively connected to the fitting 77. The hoses 75
and 76 are then joined by means of a T which has a
connection to a hose 74. The hose 74 is connected at its
other end to a vacuum pump 70. Similarly, a hose 72 is
cooperatively to the vacuum pump 70 by suitable fitting and
the hose 71 is cooperatively connected to a T which is
split off and is cooperatively connected by suitable
fittings to a first hose 72 and a second hose 73. The
first hose 72 is cooperatively connected by a suitable
fitting to the bore 31a and the second hose 73 is
cooperatively connected by a suitable fitting to the bore
33a. The pump may be any suitable vacuum pump such as the
pump made by Gast, model 0522/V3/G18DX.
Secondary passageways are formed in the first die 32
such that the bore 32a is in fluid communication with each
of the cavities 40 through 43. Secondary passageway 32b
fluidly connects the passageway 32a to the cavity 40:
passageway 32c fluidly connects the passageway 32a to the
cavity 41; secondary passageway 32d fluidly connects
passageway 32a to the cavity 32; and, secondary passageway
32e fluidly connects the passageway 32a to the cavity 43.
The secondary passageways 32b through 32e are positioned
proximate the edges of the cavities next to the sidewall
57. The secondary passageways may simply be formed by
drilling a hole from the cavity into the bore 32a. In
order to bring the secondary passageways closer to the
inner wall 57, the secondary passageways may be placed at
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an angle such that the connection to the passageway 32a is
further in than the connection to the cavities.
Similarly, the passageway 30a in the first platen 30
is fluidly connected to the cavities 40 through 43. As
shown in Figs. 3 and 4, a secondary passageway 30e is
fluidly connected between the bore 30a and the cavity 43.
Similar secondary passageways are also cooperatively
connecting the passageway 30a to the respective cavities 40
through 42.
~he second platen 31 and the second die 33 are mirror
images of the first platen 30 and the first die 32. Four
similar cavities are formed in the second die 33 which are
the mirror images of the cavities formed in the first die
32. ~he cavities in the second die 33 would, the same as
the cavities in the first die 33, correspond to the outer
profile of the article to be welded. The passageway 31a is
placed in fluid communication with the cavities by means of
secondary passages, the same as in the first die.
Similarly, the bore 32a is placed in fluid communication
with the cavities by means of secondary passageways,
similar to the first platen 30.
While the cavities have been described as being formed
in the dies 32 and 33, it is also understood that a portion
of the cavities may be formed in the platens 30 and 31 if
desired. In addition, while the jig of the present
invention has been described as having a top platen and a
bottom die as separate pieces, it is understood that they
could be formed as one piece. However, this would not be
preferred in that it would be necessary to slide the
article to be welded through the hole formed in the ~ig and
it would not be possible to separate the two to have easier
insertion of the article.
In operation, the platens 30 and 31 are spaced apart
from the dies 32 and 33 so that their surfaces are not in
contact. The vertical movement of the upper platen
assembly 29 is controlled by the activation of the
pneumatic cylinders 19 and 22. The position of the platen
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and dies in this first step is shown in Fig. 5a. ~ext~ as
shown in 5b, the stop 28 is raised to its up position. The
articles 60 through 63 to be welded are then inserted into
the cavities 40 through 43 in die 32 and into the
respective cavities of die 3i. For clarity's sake, the
articles are not shown in Figs. 5a through 5d. As
previously described, the cavities in the second die 33 are
also not shown, but are mirror images of the cavities 40
through 43. When the articles are inserted into the
cavities, they are inserted until they come up against the
stop 28. This is also shown in Fig. 3 how the articles
contact the stop 28. During this process, the vacuum pump
70 is on and is drawing a vacuum. ~owever, because the
platens are away from the dies, there is an abundance of
air which can flow into the secondary passages and
accordingly does not affect the insertion of the articles
into the cavities. When the articles have been inserted
the cavities and against the stop 28, the cylinders 19 and
22 are activated, causing the platens 30 and 31 to go
downward such that their top surfaces 50 and 51 contact the
bottom surfaces 52 and 53 of the dies 32 and 33. This is
shown in Fig. 5c. Now, with the platens against the dies,
the vacuum which is being drawn through the passages 30a,
31a, 32a and 33a take effect through the secondary
passageways and create a sucking action on the article in
their respective cavities. This is shown in Fig. 4 where
the vacuum being drawn through secondary passages 30e
maintains the profile of the article 63 by sucking on the
top surface 63a and the vacuum being pulled through
secondary passageway 32e pulls on the bottom portion 63c,
thereby maintaining the profile of the article 63.
Next, as shown in Fig. 5d, the stop element 28 is
lowered and the stop element 28 is lowered and the heating
element 27 is moved into position between the platen and
dies. The heating element is slightly narrower than the
stop element 28. This is shown in Fig. 3 in that the
heating element is shown in a dashed line and is spaced
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apart from the edge of the article 63. The vacuums through
the secondary passageways continue to pull on the articles
in the cavities, keeping their profile.
~hen, as shown in Fig. 5e, the heating element 27 is
removed and the first platen and first die are moved inward
toward the second platen and second die by movement of the
moveable tabletop 17. $his movement is controlled by the
movement of the air cylinder of the pneumatic cylinders 90.
~he articles being held in the cavities 40 through 43 then~
contact the articles being held in the respective cavities
of the second die 33. When they come in contact, they have
been sufficiently heated by the element 27 such that they
are now welded together to form a single article. The dies
32 and 33 are shown as having four cavities each. It is
understood that this could also be used with a single
cavity in each die if only two articles were to be welded.
However, the use of four cavities in each die is
advantageous when creating a gasket for a door or window.
By properly placing the four weatherstrips of the door into
the dies, a single, unitary rectangular gasket is formed.
Other combinations of cavities may also be used. The use
of such multiple cavity dies to form a single rectangular
gasket is also well known in the art.
Other modifications of the invention will be apparent
to those skilled in the art in light of the foregoing
description. This description is intended to provide
specific examples of individual embodiments which clearly
disclo3e the present invention. Accordingly, the invention
is not limited to these embodiments or the use of elements
having specific configurations and shapes as present
herein. All alternative modifications and variations of
the present invention which follow in the spirit and broad
scope of the appended claims are included.
