Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS AND METHOD FOR SEALING INSULATED GLASS UNITS
FIELD OF THE INVENTION
The present invention relates to the fabrication of insulated glass ("IG~)
units. In
particular, the present invention relates to an apparatus and method of
sealing a
spacer between a pair of spaced apart substrates.
BACKGROUND OF THE INVENTION
In the conventional manufacture of sealed insulated units comprising an
assembly
of two spaced apart parallel sheets of substrate (usually glass) and a
bondable
and/or curable spacer therebetween, assembled units are positioned in a press
and
io the entire unit is heated to melt andlor cure the spacer allowing the
spacer to bond
to the substrates. Heating of the entire unit causes problems since it
increases the
temperature of the entire unit including the air between the substrates. In
addition,
if the entire unit is being heated in the vertical position, a "chimney"effect
occurs
whereby the upper zone of the unit may become overheated relative to the lower
zone with problems resulting.
For example, in US 5,567,258, an IG unit containing an aluminum spacer,
aluminum
tape corner keys and a thermoset resin sealant is placed within a tunnel
having
microwave generators on each side. The unit passes through the tunnel and the
entire IG unit is subjected to microwave energy to bond the spacer to the
substrates.
2 0 Conventional presses ensure that the spacer is firmly bonded to the
substrates. The
entire spacer however, is heated which can result in softening of the spacer
and
changes in the shape of the spacer.
US # 4,683,154 discloses a window panel held in a spaced apart manner by glass
beads and sealed by welded glass obtained by welding the bead spacers together
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with a laser beam while positioned in a vacuum furnace. The laser welding
occurs
while the IG unit is in the furnace and is directed around the perimeter of
the IG unit
by a combination of rotating the IG unit and aiming the laser with mirrors.
Drawbacks of the conventional art include higher energy consumption, higher
heat
dissipation requirement, increased fabrication time and overheating of the IG
assembly and spacer. It is an object of the present invention to overcome the
disadvantages of the prior art by using localized zonal heating or other
energy
source to heat or otherwise induce an efFect (e.g. for curing) within the
spacer of the
IG assembly in the zones) of the assembly where the spacer is positioned
between
Zo the substrates.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided an improved
apparatus
to seal a spacer between a pair of spaced apart substrates, wherein thermal or
other
energy is applied locally to selected zones of the assembly where the spacer
contacts the substrates.
According to another aspect of the present invention, there is provided in the
above
type of apparatus a press adapted to provide sealing between a pair of spaced
part
substrates (conveniently glass) and a bondable spacer, including heat sources
adapted to move with glass substrates, specifically movably positioned to heat
the
2 o edges of the glass substrates or IG unit.
According to another aspect of the present invention, there is provided in the
above
type of apparatus a vertical press adapted to provide sealing between a pair
of
spaced apart glass substrates in generally vertical orientation and a bondable
spacer, including guide roller means.
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According to yet another aspect of the present invention, multiple localized
energy
applicator heads, preferably one per side of the IG unit are employed.
In a still further aspect of the present invention, there is provided in the
above type
of apparatus a vertical glass press adapted to provide sealing between a pair
of
spaced apart glass substrates and a bondable spacer, having at least one
heating
means synchronized to travel a desired distance with the leading edge of a
glass
substrate. The apparatus may further include a second heating means
synchronized
to travel a desired distance with the trailing edge of a glass substrate.
According to another aspect of the invention, there is provided in the above
type of
so apparatus a glass press adapted to provide sealing between a pair of spaced
apart
glass substrates and a bondable spacer, comprising a plurality of spaced-apart
compression means such as rollers or ball bearings between which a glass
assembly
is adapted to pass whereby said rollers apply compressive force to the spaced
apart
glass substrates, means for advancing a glass assembly to and through said
apparatus, a plurality of spaced apart heating means adapted to provide
localized
heating to said spacer in selected areas of said glass assembly where said
spacer
is located and without providing direct heat to the balance of said glass
assembly.
According to a further aspect of the invention, there is provided in the above
type of
apparatus a preferred heating means comprising two pairs of spaced-apart
heating
2o assemblies, at least one pair of said spaced apart heating assemblies
comprising
at least one adjustable heater adapted to move in a generally parallel
direction
relative to the other heater of said one pair.
According to a still further aspect of the invention there is provided in the
above type
of apparatus wherein said heating assembly includes a first pair of spaced
apart
heaters, one of said heaters being mounted in a fixed relationship to said
press and
the other of said heaters of said one pair being movable in a generally
parallel
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relationship to said fixed heater, and means for effecting movement of said
one
movable heater.
According to an aspect of the present invention there is provided in the above
type
of apparatus wherein the other of said pair of heaters comprises at least one
movable heater movable in a second direction relative to the direction of
movement
of said first pair of heaters, and means for effecting movement of the movable
heater
of said second pair of heaters.
In another aspect of the present invention there is provided a method of
sealing an
insulated assembly having a pair of spaced apart substrates and a spacer
io therebetween, comprising;
(a) providing an insulated assembly,
(b) providing an energy source,
(c) selectively applying energy to selected zones of said assembly where
said spacer is located without providing direct energy to the balance
of the assembly.
In still another aspect of the present invention there is provided a method of
sealing
an insulated assembly having a pair of spaced apart substrates and a spacer
therebetween, comprising selectively applying energy to selected zones of said
assembly where said spacer is located without providing direct energy to the
balance
2 0 of the assembly.
According to a further aspect of the present invention there is provided in
the above
type of apparatus wherein there is provided two pairs of heater assemblies
each pair
being mounted in an angular relationship to the other pair of heaters, each
heater
means comprising an individual heater adapted to direct a heat source to a
selected
portion of a glass assembly containing a spacer element.
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According to another aspect of the present invention there is provided a
method of
bonding a spacer to a pair of spaced apart glass substrates in which the
spacer is
positioned between the substrates; the method includes the steps of providing
a
glass assembly having a spacer between a pair of spaced apart glass substrates
and in which the glass substrates of the assembly are loosely bonded by said
spacer, providing a plurality of heat sources of an elongated relatively
narrow width
compared to the overall surface area of the glass assembly, positioning said
plurality
of heat sources in operative relationship to a glass surface beneath which the
elongated spacer is located and selectively applying heat to said spacer along
an
io elongated narrow strip of the glass assembly whereby the spacer is
preferentially
heated relative to other areas of the glass assembly.
In accordance with one aspect of the present invention, there is provided in
the
above type of apparatus a vertical press adapted to provide sealing between a
pair
of substrates and a bondable spacer material, having heat means adapted to
provide
heat to a specific area of a substrate to bond a material enclosed within said
pair of
substrates.
In accordance with another aspect of the present invention, there is provided
in an
apparatus for sealing a spacer between a pair of opposed glass substrates to
form
an insulated glass unit, the improvement comprising compression means for
2 o compressing said glass substrates against said spacer, wherein said
compression
means comprises a pair of spaced-apart cooperating compression elements, at
least
one of said compression elements comprising an elongated compression component
having a converging throat section, an intermediate compression segment, and a
diverging exit section, said intermediate compression segment having a width
less
than the width of said throat section and said exit section.
In accordance with another aspect of the present invention there is provided a
method of sealing a spacer between a pair of opposed glass substrates to form
an
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insulated glass unit, comprising the steps of providing an insulated assembly,
providing compression means, providing heating means, progressively increasing
compression on said assembly followed by decompression of said assembly,
applying heat to said assembly.
Having thus generally described the invention, reference will now be made
to the accompanying drawings illustrating preferred embodiments and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front view of the apparatus in accordance with the present
Zo invention;
Figure 2 is a top view of the compression rollers of the apparatus illustrated
in Figure 1;
Figure 3 is an end view of the apparatus illustrated in Figure 1;
Figures 4A to 4G inclusive diagrammatically illustrate the various sequential
steps and associated apparatus for the heat sealing of an IG unit;
Figure 5 is a perspective view of a portion of another apparatus with certain
components removed in accordance with the present invention;
Figure 6 is a perspective view of the apparatus of Figure 5 with the vertical
heating and pressing assemblies shown;
2o Figure 7 is a partially exploded view of a vertical heating and pressing
assembly of Figure 6;
Figure 8 is a partially exploded view of the rails of the vertical station of
the
apparatus of Figure 6;
Figure 9 is a partially exploded perspective view of a horizontal heating and
pressing assembly of the apparatus of Figure 6;
Figure 10 is a perspective view of the conveyor system of the apparatus of
Figure 6;
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Figure 11 is a side view of the clamping system of the vertical heating and
pressing assemblies of Figure 6; and
Figure 12 is an end view from the exit end of the horizontal heating and
pressing assembly of Figure 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The terms "height" and "width" and "vertical" and "horizontal" when used
herein in
reference to the IG assemblies refers to the IG assembly positioned generally
vertically. The term "thickness" refers to the transverse axis across the
substrates.
"Left" and "right" are in reference to a viewer at the leading edge of the
apparatus
Zo viewing the assembly along the axis of travel of the IG assembly being
treated. 1G
assembly includes assemblies having substrates of glass or other suitable
material
such as plastic or aluminum.
Referring to Figures 1 to 3, the press apparatus includes an energy applying
station
in the form of a heating station indicated generally by H and a pressing
station
indicated generally by P. The press apparatus is designed to be part of a
conventional continuous production line process for the manufacture of IG
units but
alternatively may be used as a stand-alone unit as well. Advancing means in
the
form of a conveyor 12 mounted in a base 10 links stations H and P.
An IG unit 15 to be treated is conveyed by the conveyor 12 sequentially to
stations
2 o H and P in a nearly vertical position with the substrates 13 of the IG
unit 15 being
generally vertical with respect to the conveying surface 125 of the conveyor
12. It
will be understood, however, by those skilled in the art that the present
invention
may be used to treat units conveyed to the press apparatus in the horizontal
position.
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The conveying surface 125 is inclined preferably approximately 5 degrees with
respect to the horizontal such that the IG unit 15 to be treated tilts to one
side of the
conveyor 12. The conveyor 12 may be controlled by suitable timing means to
move
an IG unit 15 as desired between the stations H and P.
The heating station H includes upper and lower assemblies indicated generally
by
110 and 112. The lower assembly 112 is mounted on the base 10 and houses lower
left and right horizontal heater housings 32L and 32R and guide roller 132.
The
housings 32L and 32R further house a plurality of linearly mounted heater
means 28.
The horizontal heater housings 32L and 32R are movably housed within the
Zo assembly 112 by suitable means such that the separation between the
housings
32L and 32R can be altered to accommodate IG units 15 of various thicknesses.
The
horizontal position of the lower assembly 112 is fixed but can be made
adjustable by
suitable means if needed.
The upper assembly 110 is mounted to support 113 which includes height
adjustment means to adjust the spacing between the upper and lower assemblies
110 and 112, thus permitting the press apparatus to accommodate IG assemblies
of various sizes. The upper assembly 112 includes left and right spaced apart
upper
horizontal heater housings 30L and 30R and a single guide roller 130. The
housings
30L and 30R further house a plurality of linearly mounted heater means 28. The
2o horizontal heater housings 30L and 30R are movably housed within the
assembly
110 by suitable means such that the separation between the housings 30L and
30R
can be altered to accommodate IG units 15 of various thicknesses.
Guide roller 130 is movable with the housing 30L. The guide rollers 130 and
132
support the IG assembly while in the station H. Additional guide rollers may
be used
if needed.
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The heating station H further includes left and right leading and trailing
vertical
heater housings 40L, 40 R and 50L, 50R respectively. The vertical heater
housings
40L, 40R and 50L, 50R are tilted by an amount equivalent with the incline of
the
conveying surface 125 and each further house a plurality of linearly mounted
heater
means 28. The heater means 28 are any suitable means such as electric, gas
known in the art e.g. heat lamps and the housings 30L,30R, 32L,32R, 40L,40R
and
50L,50R are constructed of suitably heat resistant materials such as aluminum.
Means are provided to selectively activate and deactivate the heater means 28
when
desired.
1o Leading vertical housings 40L,40R are movably mounted on the base 10 to
move
with the leading edge of the IG unit 15 between a home position, when an IG
unit 15
first enters station H, and an end position at the end of the heating cycle.
Trailing
vertical housings 50L,50R move between like positions with the trailing edge
of the
IG unit 15. The travel distance of the vertical housings 40L,40R and 50L,50R
with
the IG unit is determined by the desired heating time and can be varied as
will be
appreciated by those skilled in the art.
The housings 30L, 30R, 32L, 32R, 40L,40R and 50L,50R are designed to focus
heat
from the heater means 28 on the zones of the IG assembly where the spacer 11
is
positioned and to reduce or eliminate heating of the balance of the IG
assembly.
2 o The area of the heated zone corresponds approximately with the area of
contact of
the spacer 11 with the substrate 13.
The pressing station P includes pressing means in the form of two converging
press
belts 60 having a wider separation at the beginning of the station P than at
the end
to provide a progressively decreasing passage channel through which an IG unit
15
will pass. The starting and ending separation of the belts 60 will be
commensurate
with the thickness of the IG unit 15 and the belts 60 can be optionally
mounted on
the base 10 such that the separation between the belts is adjustable manually
or
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automatically to accommodate various thicknesses of IG units 15. Other
suitable
pressing means may be used such as a series of compression rollers of
progressively decreasing separation, and presses of the "butterfly" type. The
press
belts 60 are tilted according to the incline of the conveying surtace 125 such
that an
IG unit 15 will pass along generally the same plane from station H to station
P.
Figures 4A through 4G show the press apparatus in operation. Referring to
Figure
4A, an IG unit 15 is advanced by the conveyor 12 to the station H. If the
press
apparatus is part of an automatic line, the IG unit is advanced to the station
H from
a previous station on the line such as an automatic spacer application
station. The
to horizontal heater housings 30L,30R and 32L, 32R are positioned such that
the
spacer segments 11 along the upper and lower edges of the IG unit 15 will be
adjacent the horizontal heater means 28 in housings 30L,30R and 32L, 32R which
are activated in the housings 30 and 32 as the IG unit 15 is advanced to the
position
shown in Figure 4B. Vertical housings 40L,40R and 50L,50R are in the home
positions out of the path of the advancing IG unit.
As shown in Figure 4B, the IG unit 15 is resting on the conveyor 12 tilted to
one side
of the conveyor 12 and supported laterally by the guide rollers 130 and 132.
Leading vertical housings 40L,40R are in the home position adjacent the spacer
11
along the leading edge of the IG unit 15. Trailing vertical housings 50L,50R
are in
2 o the home position adjacent leading vertical housings 40L and 40R. The
energy
generating means 28 in housings 30L,30R, 32L,32R and 40L,40R are activated to
heat the adjacent spacer 11.
As shown in Figure 4C, leading vertical housings 40L,40R are in the end
position
having traveled with the leading edge of the IG unit 15 and upon reaching the
end
position, have been deactivated to prevent heating of the IG unit 15 in zones
without
spacer 11 as it advances past the housings 40L,40R. The heater means 28 in
housings 30L,30R and 32L,32R are still activated.
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As shown in Figure 4D, the leading edge of the IG unit 15 has advanced beyond
the
leading vertical housing 40L,40R and into the station P. The trailing edge of
the IG
unit 15 has cleared the housings 30L,30R and 32L,32R and the energy generating
means 28 therein have been deactivated. The trailing edge of the IG unit is
now
adjacent the home position of the trailing vertical housings 50L,50R and the
heater
means 28 therein are activated.
As shown in Figure 4E, the trailing vertical housing is in the end position
having
traveled with the trailing edge of the IG unit 15 as it advanced and upon
reaching the
end position, has been deactivated. Almost the entire length of the IG unit 15
is now
Zo with station P where the IG unit 15 is being progressively pressed together
to bond
the spacer 11 to the substrates 13 to form a sealed the IG unit.
As shown in Figure 4F, the IG unit 15 has cleared the station P and a
subsequent
IG unit 15 is advancing into the station H.
As shown in Figure 4G, the vertical housings 40L,40R and 50L,50R have returned
to their respective home positions and the heating means in housings 30 and 32
are
activated to recommence the cycle.
Referring to Figures 5 to 12 in another embodiment of the present invention,
the
press apparatus includes a vertical energy applying and pressing station shown
generally as 200 and a horizontal energy applying and pressing station shown
2 o generally as 210.
Vertical Station 200
An IG unit to be sealed advances on conveyor 220 to the vertical station 200.
The
vertical station includes two vertical heating and pressing assemblies 230 and
232.
The assembly 230 is the trailing edge assembly, while the assembly 232 is the
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leading edge assembly. The heating and pressing assemblies 230 and 232 are
each supported and guided by upper and lower rails 240 by means of upper and
lower blocks 250 which slide along the top edge of each rail 240. The rails
240 are
shown in greater detail in Figure 8. The rail 240 has an inside edge 260 which
is
tapered in profile. The surface 260 is furthest from the outer edge 280 in the
mid
section of the rail 240 and closest to outer edge 280 at the end sections. The
taper
is achieved by slots 300 which permits the surface 260 to be tapered toward
the
outer edge 280.
Referring to Figure 7, each vertical heating and pressing assembly 230 and 232
Zo includes a set of guide rollers 310 mounted on a support 320 for guiding
the IG
assembly. The support 320 is attached to main plate 340 with spacer blocks
360.
The main plate 340 includes a pressing surface 380 which contacts the glass of
the
IG unit. The pressing surface 380 is a heat resistant material such as
phenolic fiber.
Heating elements 402 are mounted between the support 320 and main plate 340.
The heating element 400 can be the energy generating means 28 as previously
described.
The assemblies 230 and 232 are shown in their respective home positions in
Figure
6. The assemblies 230 and 232 are mounted on the rails 240 such that the
pressing
surfaces 380 are opposed to each other.
2o The separation of the surfaces 380 must be sufficient to permit the width
of the
assembly to pass therebetween without being significantly pressed. The
assemblies
230 and 232 move along the rails between their home position and the other end
of
the rails near the horizontal station 210. As the assemblies 230 and 232 move
toward the other end of the rails, the separation between the pressing
surfaces 380
progressively dea-eases until the mid section of the rails 240 is reached,
after which
point the separation increases until the separation is once again such that
there is
no significant pressure on the IG unit. The movement of the assemblies 230 and
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232 are timed with the conveyor 220 such that the assemblies 230 and 232
advance
together with an advancing IG unit. The timing means for the conveyor and
assemblies 230 and 232 is shown in Figure 10. Timing belts 400 and 410 rotate
around pulleys 420 on a middle pulley assembly 430.
The conveyor 220 likewise rotates around pulley 440 of middle pulley assembly
430
and guided by guide assembly 442. The belts 400 and 220 are at their other
ends,
turn around pulleys 460 of the front pulley assembly 480. Both belts 400 and
220
are driven by belt 500 rotating around drive pulley 510. Belt 500 is driven by
motor
520 at its other end. Motion is transferred from the motor 520 via belt 500 to
drive
1o pulley 510 and corresponding pulley 420, and then to belt 400 via timing
belt 410.
Conventional motion sensors (not shown) sense the position of an incoming IG
unit
and in turn control grippers 530 which clamp the advancing IG unit to advance
it
toward the horizontal station 210. The clamping operation performed by the
four
grippers 530 is synchronized to grip the IG unit such that it is advanced
together with
the assemblies 230 and 232.
Each gripper 530 has an upper clamp 532 and lower clamp 534 which are actuated
by air cylinders 536. A gripper 530 is connected to each assembly 230 and 232.
With the belt 400 running, the assemblies 230 and 232 are advanced by
actuating
the cylinder 536 of upper clamp 532 to press upper clamp 532 against anvil
538.
20 Similarly, lower clamp 534 is actuated to return the assemblies 230 and 232
to the
home position.
Referring to Figure 6, in operation, an IG unit to be sealed such as that
described
previously as IG unit 15 is advanced by conveying means 220 to the assemblies
230
and 232 shown in the home position. The IG unit passes through the separation
between the pressing surfaces 380 of first the trailing assembly 230 and then
the
leading assembly 232, at which point the upper clamps 532 of the grippers 530
of
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the leading assembly 232 are actuated to clamp the assembly 232 to the belt
400.
The assembly 232 now moves with the belt 400 and in turn is synchronized with
the
advancing movement of the IG unit being carried by conveyor belt 220. The
assembly 232 is timed by conventional sensors (now shown) to be clamped to
belt
400 when the spacer 11 is adjacent the heating element 402.
As the assembly 232 advances toward horizontal station 210, the separation
between the pressing surfaces 380 of the assembly 232 diminishes which in turn
progressively increases the pressure being applied to the substrates 13 to
press
them together. The heating element 402 is activated at this time to heat the
to substrates 13 adjacent the area where the vertical sections of the spacer
11 are
located as the spacer 11 is being squeezed by the substrates 13. This heats
the
outer surfaces of the spacer 11 which contacts the substrates 13. Heating
continues
until the maximum pressing force is achieved around the mid point position of
the
rails 240 at which time the heating element 402 is switched off. As the IG
unit 15
advances beyond the midpoint of station 200, the separation of the pressing
surfaces 380 increases until the substrates 13 are no longer being pressed
together.
While the leading assembly 232 is advancing, the trailing edge of the IG unit
15 will
be moving though the trailing assembly 230. Once sensors (not shown) indicate
that
the trailing edge of the IG unit is passing through the trailing assembly 230,
the
2 o upper clamps 532 of the grippers 530 of the trailing assembly 230 are
actuated to
clamp the assembly 230 to the belt 400. The trailing assembly 230 then moves
with
the trailing edge of the IG unit 15 in the same manner as that described above
with
respect to the leading edge. The trailing vertical segments of the spacer 11
are also
similarly pressed and heated.
It will be appreciated that the heating element 402 can be switched on at
various
points during the advancing of the assemblies 230 and 232 to achieve various
heating and pressing sequences, such as initial pressing of the substrates 13
and
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spacer 11 followed by simultaneous pressing and heating as described above. An
alternative sequence is to begin heating immediately followed by pressing. It
has
been found that simultaneously pressing together of the substrates against the
spacer and heating yields a good bond between the spacer and the substrates.
It will also be appreciated that the principles embodied in the vertical
station can also
be employed to seal horizontal sections of spacer between substrates.
Horizontal Station 210
As the IG unit being sealed exits the vertical pressing station, it enters the
horizontal
pressing and heating station 210. The station 210 includes upper and lower
1o horizontal heating and pressing assemblies 600 and 610.
Referring to Figure 9, the upper assembly 600 includes two horizontal support
plates
620 and 622, below which are attached a linear array of pressing rollers 630
for
guiding IG units. The plate 620 is fixed while the plate 622 is movable
towards and
away from the plate 620 to accommodate different thicknesses of IG units. A
heating element 650 is mounted on each plate 620 and 622.
The assembly 600 includes opposed arrays of pressing rollers 630. The
separation
of the guide rollers 630 is greatest at the entry end of the assembly 610
shown
generally at 660, and tapers to a narrower separation at the exit end shown
generally at 670. The heating elements 650 follow the same tapering path as
the
2 o pressing rollers 630. The heating elements 650 heat the substrates 13 near
the top
edge of the IG unit adjacent the location of the spacer. Energy is transferred
through
the substrates 13 to heat the outer surfaces of the spacer 11 where it
contacts the
substrates 13.
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At the entry end 660, the separation of the pressing rollers 630 permits
passage of
the top section of an IG unit without significantly pressing it together. As
an IG unit
proceeds towards the exit end 670, it is progressively pressed together by the
pressing rollers 630.
The lower heating and pressing assembly 610 is identical to the upper assembly
600
except it is mounted inverted with respect to assembly 600. The pressing
rollers 630
are above the plates 620 and 622 and the heating elements (not shown) are
below
the rollers 630.
The separation between the assemblies 600 and 610 can be adjusted to
to accommodate different sizes of IG units by raising or lowering the upper
assembly
600 by motor 680 and other suitable means. The pressing rollers 630 on the
assemblies 600 and 610 are inclined downwardly by approximately 3°
toward the exit
end 670. This imparts downward pressure on an IG unit to press it onto the
conveyor 220 to advance it. The conveyor belt 220 passes below the lower
assembly 610.
In operation, as suitable conventional motion sensors (not shown) detect the
IG unit
15 entering the station 210, the heating element 620 in each assembly 600 and
610
is activated to heat the substrates 13 adjacent to the upper and lower
horizontal
sections of the spacer 11. As the IG unit 15 advances towards the exit end
670,
2o significant pressure begins to be applied to the substrates 13 around the
midpoint
of the station 210. From the mid point, simultaneous heating and pressing
occurs.
It will be understood that the heating elements 650 can be varied to adjust
the
amount of heating as well as to vary the timing of the heating with respect to
the
pressing.
After the IG unit 15 exits the station 210, the sensors and heating element
650 reset
for the next IG units to be processed.
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As will be understood, various modifications to the present invention can be
made
including arranging the heater means in a "picture frame" type assembly
whereby the
entire spacer is heated at one time, or alternatively, using a heater means
which
travels around the periphery of the IG unit to heat the spacer. A platinum
press can
also be employed with suitable modifications.
