Note: Descriptions are shown in the official language in which they were submitted.
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PLUG CONNECTOR FOR RETAINING HOLLOW SECTIONS
FIELD OF THE INVENTION
This invention relates to plug connectors as inserts for retaining hollow
sections,
especially for perimeter spacer frames or bar sections of window insulating
glass panels, and
to process of manufacturing said connectors; and to spacer frames having said
connectors
retained within said window.
BACKGROUND OF THE INVENTION
Windows with multiple pane glazings are used in buildings where improved
temperature and noise insulation are desired. Part of the assembly of the
multiple glazing
window is a spacer frame around the full perimeter within the window frame
which holds the
panes apart and parallel to each other, at a fixed gap. Sealant is applied to
form a single
multi-pane unit.
Generally, the spacer frame is a hollow, rectangular section spacer tube, made
of
extruded or roll formed aluminum. The spacer is generally filled with
desiccant material to
absorb any moisture that is captured during the manufacturing process and,
thus, to prevent
internal fogging of the window at low temperatures. It is critical that
flatness of the spacer
tube be maintained precisely when the multi-pane glazing unit is sealed to
provide an
effectively sealed unit.
In the manufacturing process and in the performance of the window, it is an
advantage to have the initial free ends of the spacer tube subsequently
connected and retained
to each other to provide a fully continuous peripheral frame. So-called "plug-
in", preferably,
linear connectors are used to provide this connection. One version of a linear
connector is
U-shaped in cross-section formed sheet metal article that fits into each
abutting hollow end of
the spacer tube. In one type of plug connector described in United States
Patent No.
6,862,859 B2 to Max Kronenburg - issued March 8, 2005, lateral retaining barbs
are formed
in the outer periphery of the U`legs and retain the connector to the spacer
frame ends.
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Although the lateral retaining barbs are effective retaining devices, they,
typically,
functionally compromise the spacer tube into which they are inserted in that
the lateral
retaining barbs cause outward deformation of the spacer tube, with a resulting
local increase
in thickness of the tube. This disadvantage is made worse by the fact that
this outward
deflection acts on the planes of the spacer tube which, typically, carry vent
perforations and
extrusion or roll forming seams. In consequence, in order to effectively seal
the multi-pane
glazing, the spacer tube strength and, therefore, its cost must be increased
to reduce the
degree of local deformation and/or the amount of sealant increased to
accommodate the
deformation at increased cost.
Further drawbacks to the use of such lateral retaining barbed connectors is
particularly
seen in the manufacturing process and in the performance of the sealed window
unit. This is
in consequence that the linear connection plugs are required to have a certain
bending and
torsional stiffness. Forming the retaining barbs from the periphery of the
plug connector
compromises both of these physical characteristics. These must be compensated
for by
increasing the thickness of the sheet metal used in the forming of the
connector.
It will be understood by the person skilled in the art that the spacer tube
must be made
of very uniform overall lateral dimension to ensure efficient sealing against
each of the
window glazings. Sealing is critical to prevent moisture seeping in and
causing internal
fogging. The more uniform the lateral spacer dimension is kept, the less
sealant is required to
ensure a full seal. Further, window spacer tubes are manufactured, typically,
with ventilation
perforations punched in the inner surface and with a longitudinal seam along
the center of the
outer surface. These features makes the spacer tube weak in the lateral
direction.
Most existing connectors have retaining barbs that act laterally on the spacer
tube,
which in combination with the weakness of the spacer tube in the lateral
direction, results in
outward lateral deflection of the spacer tube. There are also existing
connectors which act
vertically in the centre of the spacer tube. This results in an inward lateral
deflection of the
spacer tube side walls. Both of these unsatisfactory situations must be
addressed by
increasing the amount and, accordingly, cost of sealant used.
United States Patent No. 5,560,731 - issued October 1, 1996 to Max Kronenberg
discloses U-shaped plug connectors optionally having a center web with
retaining elements
formed as resilient, bent-out lugs which claw into the inside, walls of the
hollow frame
section to oppose the extraction of the connector. The essential resilient
character of the
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retaining elements is to compensate for the inside tolerances and provide a
firm fit with the
hollow sections. USP 5,560,731 is silent on the location of the retaining
elements in the
center web. Further, alternative connectors having no center web retaining
elements or with
also side web retaining elements are described. USP 5,560,731 is silent on the
desirability of
having no centrally located retaining elements on the central web as to
prevent side pressures
on the side webs.
There is, therefore, a need for an improved connector that does not suffer
from the
aforesaid disadvantages.
SUMMARY OF THE INVENTION
The present invention provides plug connectors that act in the non-critical
vertical
direction, intermittently at the corners with the solid side walls of the
spacer tube, or
immediately adjacent thereto in the center web. Deflections of the spacer tube
are, thus,
advantageously, only in the vertical direction and of a very small magnitude.
Lateral
deflections are eliminated, and the multiple window glazings can be
efficiently sealed with a
minimum of sealant.
The connectors according to the present invention do not have the retaining
elements
on the side walls and, thus, are so oriented as to not act in the critical
direction on the spacer
tube side walls. The absence of side pressure on the critical side walls
results in the retention
of flatness for pane sealing. It also provides for reduced buckling by
retention of alignment
of spacer ends from uninterrupted external profile maintenance. The connectors
provide a
lower cost method for keeping dimensional control and offer a positive lock
behind the pairs
of longitudinally arranged perforations in those spacers having such features.
Further, the manufacturing functionality of the connector according to the
invention is
improved over that for connectors having retaining means formed out of the
side wall lower
edge.
It is an object of the present invention to provide a connector for retaining
hollow
sections that does not functionally compromise the sections without the need
for enhanced
section thickness or amount of sealant.
In a further object, the invention provides multi-space perimeter spacer
frames
retained with said connectors.
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In yet a further object, the invention provides a method of manufacturing said
connectors.
Accordingly, in one aspect the invention provides a plug connector for hollow
sections for spacer frames or bar sections of insulating glass panes, said
connectors
comprising a longitudinal middle web and two parallel side walls joined to
said middle web
to provide a pair of parallel longitudinal corners, and a plurality of
retaining means
intermittently spaced at or immediately adjacent said corners in said middle
web;
said retaining means comprising
(i) first retaining elements so shaped as to allow entry and retention of a
first desired
portion of said connector into a first portion of a hollow section in a first
direction but prevent
withdrawal of said first desired portion from said first portion of said
hollow section in the
reverse direction to said first direction and
(ii) second retaining elements so-shaped as to allow entry and retention of a
second
desired portion of said connector into a second portion of a hollow section in
said reverse
direction but prevent withdrawal of said second desired portion from said
second portion of
said hollow section in said first direction.
Preferably, a connector as hereinabove defined has each of said first and
second
retaining elements comprising an inclined place portion and retaining edge
portion.
Preferably, the inclined plane portion and retaining edge portion comprise a
non-
resilient body.
Preferably the retaining elements are located at intermittent portions of the
aforesaid
corners.
In alternative embodiments, a connector as hereinabove defined has the
retaining
elements located at a distance selected from 0.5mm to 3mm from the corners.
Most preferably, a connector as hereinabove defined has said web integrally
formed
with said side walls.
Preferably, a connector as hereinabove defined is wherein each of said side
walls has
a hollow section stop to limit entry of said insert into said hollow section.
Connectors according to the invention in the form of linear embodiments within
and
for joining two hollow sections are preferred. Corner connectors according to
the invention
for use in corners formed by the joining of two hollow sections to form a
corner are also
readily manufactured and used.
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Connectors formed of any suitable materials may be used. Preferred material is
steel.
In a further aspect, the invention provides a spacer frame assembly comprising
(a) a spacer frame having an inner wall having an inner surface defining a
rectangle
and an opposing outer wall spaced from said inner wall by a pair of side
walls, and wherein
said inner and outer walls and said side walls define a hollow section; and
(b) a plug connector as hereinabove defined within said spacer frame.
The middle web is preferably in abutment adjacent the inner spacer wall, but
the
connector reverse position may be used wherein the middle web is in abutment
with the outer
spacer wall.
In preferred embodiments the assembly as hereinabove defined has said inner
spacer
frame wall provided with at least a pair of parallel longitudinal series of
perforations.
In preferred embodiments the connectors of the present invention are formed of
a
material and so shaped as to minimize the amount of resilient flexibility
experienced by the
retaining elements.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be better understood, preferred embodiments
will now
be described by way of example only with reference to the accompanying
drawings, wherein
Fig. 1 is a perspective diagrammatic view of a linear plug connector according
to the
invention;
Fig. 2 is an enlarged view of a retaining element shown in Fig. 1;
Fig. 3 is a diagrammatic perspective view of a linear connector located within
hollow
sections of spacer frames according to the invention;
Fig. 4 is a diagrammatic perspective view of a part of an enlarged linear
connector,
within a hollow section, in part, according to the invention;
Fig. 5 is a diagrammatic perspective view of a corner connector according to
the
invention;
Fig. 6 is a diagrammatic perspective view of a corner connector, located
within a
hollow section of spacer frame according to the invention;
and wherein the same numerals denote like parts.
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Fig. 1 shows generally as 10 steel linear connector having a longitudinal
middle web
12 and parallel side walls 14, 16 integrally formed with web 12 to provide
parallel
longitudinal corners 18, 20, respectively.
Intermittent along middle web 12 at a first portion 23 at corners 18, 20 is a
first series
of retaining elements 22 and a second series 24 at a second portion 25 of
connector 10. Each
of retaining elements 22, 24 has an inclined face portion 26, 28,
respectively.
Each side wall 14, 16 has an insertion stop 30, 32, respectively, to prevent
insertion of
connector 10 past its mid-point 34 inside spacer frame 46.
Connector 10 has a plurality of stiffening ribs 38, 40, 42 and 44 suitably
located, one
adjacent each end and at central portions.
Figs. 5 and 6 illustrate corner connectors according to the invention within
and
without hollow frame sections, respectively.
In operation, with reference also to Fig. 3, when first portion 23 is inserted
into
hollow section 46 in direction A, inner wall 48 of section 46 rides over, with
deformation,
over elements 22 adjacent corners 18, 20 until stop 30 reaches side walls of
section 46.
Connector 10 is held in abutment by retaining elements 22 acting on inner wall
of section 46.
When second portion 25 of connector 10 is inserted into hollow section 50 in
direction B, inner wall 52 of section 50 rides over, with deformation, over
elements 24
adjacent corners 18, 20 until stop 32 reaches side walls of section 50 to
retain connector 10 in
abutment with section 50.
Retaining elements 22, 24 are located adjacent corners 18, 20.
In the above embodiments, with reference also to Figs. 4 and 6 retaining
elements 22
and 24 of center web 12 adjacent corners 18,20 abut inner walls 48, 52 of
hollow sections at a
distance of about 2-3 mm laterally across inner walls 48, 52 and absent from
the area "C"
between perforation series 54, 56.
The linear connector is preferably manufactured from a coil of flat steel by
it being
fed to a series of stamping dies where the shape is created by cutting off the
unwanted
material around the perimeter of the connector. A narrow feeder strip is left
to keep the
connector joined to the one ahead, and the one behind. A second station is
also a cutting
station, which punches out material to create the interior cut-outs. At a
third station, a press
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bends the areas of the retaining features, the insertion stops and the lead-in
bevels to their
final angles. At a next station, a press bends the walls to their final
orientation and forms the
stiffening ribs in the upper web of the connector. At a final station, the
part is fully separated
from the steel coil by trimming off the feeder strip.
Although this disclosure has described and illustrated certain preferred
embodiments
of the invention, it is to be understood that the invention is not restricted
to those particular
embodiments. Rather, the invention includes all embodiments which are
functional or
mechanical equivalence of the specific embodiments and features that have been
described
and illustrated.
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