Note: Descriptions are shown in the official language in which they were submitted.
CA 02550052 1998-02-04
v
SYSTEM FOR FABRICATING MUNTIN BARS
FROM SHEET IyIATERIAL
Field of the Invention
The present invention relates to the fabrication of insulating glass units fox
windows, and more particularly to a system for fabricating muntin bars used in
the
construction of insulating glass units.
1o Back;eround Art
Windows constructed from multiple glass panes utilized "muntins" or
"muntin bars" to secure the edges of the individual glass panes within the
window
sash. In many windows, muntins formed distinctive grid patterns which became
associated with architectural styles of buildings containing the windows.
~.5 Modern windows formed by insulating glass units utilize single glass
lights
separated by an insulating dead air space. Where a particular architectural
"look"
is desired, a grid of muntin bars is fixed in the dead air space between the
glass
lights to simulate a multipane window. Typical muntin bars for insulating
glass
units are formed fxom~ decoratively coated interfitted metal tubes. The gxids
are
2 o anchored to the insulating glass unit periphery.
Constructing muntin bar grids for insulating glass units has been a labor
intensive process. As a consequence, manufacturing such units, and thus
windows
formed by the units, has been costly and inefficient. Some efforts to
mechanize
the manufacture of muntin grids have been made. For example, machines for
25 notching lengths of preformed tubular muntin bar stock at predetermined
locations have been proposed. The muntin bar stock is cut into lengths fox use
in
forming a grid for a given size insulating glass unit. The cut muntin bar
stock is
then fed into the notching machine and notches are formed at predetermined
locations along each length. The grids are assembled by hand by interfitting
the
o respective muntin bars at the notches.
The muntin bar stock is produced by roll forming decoratively coated slieet
material such as aluminum or steel, in a known manner. Various sizes of the
sheet material are used to fortri different size muntin bar stock. The roll
forming
CA 02550052 1998-02-04
1
machine has a series of rolls configured to form sheet material into elongated
tubular muntin bar stock. A window manufacturer purchases the muntin bar stock
sizes) needed to produce insulating glass units and, as described above, cuts
the
stock into lengths that are notched and assembled into grids for incorporation
into
the insulating glass units.
Conventional muntin bar constructions suffer from several drawbacks with
respect to cost and efficiency. For example, insulating glass unit
manufacturers
are required to purchase and maintain an inventory of tubular muntin bar
stock.
In some instances, several different muntin bar stock sizes and colors are
1 o inventoried to produce grids for various insulating glass units. This
necessitates
dedicated muntin bar stock storage space and increases costs associated with
inventory. In addition, the muntin bar stock must be cut into lengths the size
of
which depends on the size of the insulating glass units being manufactured.
While
dedicated machinery may be used to cut the stock, a machine operator is still
required to perform at least some hand measurements in order to produce
correctly cut-to-length muntin bars. Moreover, cutting the muntin bar stock
frequently results in unusable scrap.
The cut-to-length muntin bars are then fed to a notching device to form
notches that will be located at the muntin bar intersections. Although some
2 o machinery may be specialized to notch the bars for forming grids, a number
of
hand measurements typically must be made so as to produce correctly sized
muntin bars with properly located notches. As a result, conventional
construction
of muntin bars and muntin bar grids requires the operator to perform a series
of
complicated measuring and fabricating steps, thereby increasing the difficulty
and
2 5 cost associated with such construction. The handling and notching
procedures
may also adversely affect the appearance of the muntin bar by damaging the
muntin bar finish and denting or creasing the bar.
The present invention provides a new and improved system for fabricating
muntin bars which is so constructed and arranged that stock sheet material is
3 o quickly and efficiently formed into individual muntin bars that include
notches, or
other structure, to permit the bars to be subsequently attached to form a
grid,
without requiring significant handling or mentation on the part of the
individual
2
CA 02550052 1998-02-04
i
'c
fabricating the muntin bars. The invention provides a method and apparatus
for,
continuously producing notched muntin bars from stock material; thus, a
manufacturer is able to store coils of stock material rather than a supply of
precut
tubular muntin stock. Also, production of the muntiri bars is automatically
controlled to allow muntin bars to be custom formed for specific orders.
Summary of the Invention
A preferred method of making a muntin bar includes steps of providing a
supply of sheet material in the form of thin ribbon stock having a finished
surface,
1 o feeding the ribbon stock to a first forming station comprising a punching
mechanism, and punching the ribbon stock at a precisely predetermined
location.
The ribbon stock is delivered from the first forming station to a second
forming
station comprising a succession of forming rolls and is passed through a
succession
of forming roll nips to produce a tube having a desired cross-sectional shape.
The
tube is delivered from the second forming station to a third forming station
comprising a severing apparatus and is severed at a precisely predetermined
location. In preferred embodiments, after severing, a muntin bar handling
station
comprising a conveyor moves the muntin bar to a desired location. A preferred
apparatus for making muntin bars comprises a ribbon stock supply station and
2 0 first, second and third forming stations that process the stock into
notched muntin
bars.
Brief Description of the Drawings
Other features and advantages of the invention will become.apparent from
2 5 the following detailed description of preferred embodiments thereof taken
in
conjunction with the accompanying drawings, wherein:
Figure 1 is a perspective view of an insulating glass unit including a muntin
bar grid constructed according to the invention;
Figure 2 is an enlarged perspective view of a portion of the muntin bar grid
3 0 of the insulating glass unit of Figure 1;
Figure 3 is a plan view of a portion of stock material partially processed
according to the invention;
3
CA 02550052 1998-02-04
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Figure 4 is an elevation view schematically illustrating forming the stock
material of Figure 3 into a muntin bar;
Figure 5 is a front elevation view of a muntin bar production line
constructed according to a preferred embodiment of the invention;
Figure 6 is a plan view of the production line of Figure 5;
Figure 7 is an enlarged front elevation view of a stock supply station
forming part of the production line of Figure 5;
Figures 8A-8C are, respectively, an enlarged rear elevation view, end
elevation view, and plan view of a first forming station forming part of the
production line of Figure S;
Figure 8D is an enlarged elevation view of a portion of the first forming
station of Figures 8A-8C;
Figure 9 is an enlarged front elevation view of a second forming station
forming part of the production line of Figure 5;
Figure 10 is a plan view of the forming station of Figure 9 seen
approximately from the plane indicated by the line 10-10 in Figure 9;
Figures 11A-11C are, respectively, an enlarged front elevation view, end
elevation, and plan of a third forming station forming part of the production
line
of Figure 5;
2 0 Figures 12A-12C are, respectively, an enlaxged end elevation view, a rear
elevation view, and a plan view of a muntin bar handling station forming part
of
the production line of Figure 5, the handling station including an optional
adhesive applicator;
Figures 13 is an enlarged front elevation view of a second forming station
2 5 constructed according to an alternative embodiment of the invention;
Figure 14 is a plan view of the forming station of Figure 13 seen
approximately from the plane indicated by the line 13-13 in Figure 13;
Figure 15 is an enlarged rear elevation view of the forming station of
Figure 13;
3 o Figure 16 is an enlarged front elevation view of a stock supply station
constructed according to an alternative embodiment of the invention;
4
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Figure 17 is a plan view of the stock supply station of Figure 16 seen
approximately from the plane indicated by the line 17-17 in Figure 16; and
Figures 18A-18C are, respectively, an enlarged front elevation view, end
elevation view, and plan view of a mechanism constructed according to an
alternative embodiment of the invention fox forming a muntin bar from a tube
that has not been notched.
Detailed Description of Preferred Embodiments
Figure 1 shows an insulating glass unit indicated generally by the reference
to numeral 10 comprising a spacer assembly 12 sandwiched between glass sheets,
or
lites, 14. The spacer assembly 12 includes a frame assembly 16 hermetically
joined
to the glass lites by a sealant 18 to form a closed dead air space 20 between
the
lites. The unit 10 is illustrated in Figure 1 in condition for assembly into a
window or door frame (not shown).
A mundn bar grid indicated at G is disposed between the glass lites to
provide the unit 10 with the appearance of a mufti-pane window. As seen in
Figure 2, the illustrated grid G is comprised of muntin bars M having mating
notches 190 interfitted at an intersection I to form a lap joint. The bars are
preferably, though not necessarily, secured together by a suitable adhesive
2 o indicated at A. The ends of the muntin bars M are secured to the interior
of the
spacer frame 16 by suitable fasteners as is known in the art. Muntin bars
formed
according to the invention may have any desired cross sectional configuration.
In
the illustrated embodiment, muntin bars M have a rectangular cross sectional
configuration formed by major side faces, or panels, 186a, 186b and edge, or
end,
panels 184, 188.
Figure 3 shows a length of stock material S suitable for being formed into a
muntin bar M according to the invention. The stock material S, the opposite
major surfaces of which may be coated or otherwise treated to produce a
decorative color or pattern, is preferably in the form of thin metal ribbon
stock,
3 o for example, aluminum or steel. According to the invention, the ribbon
stock S is
fed lengthwise through a muntin bar production line including a series of
forming
stations that transform the stock into the notched muntin bar M. The ribbon
5
CA 02550052 1998-02-04
stock S includes opposite edges 180a, 180b that, along with fold lines 182a,
182b
define edge panels 184a, 184b. When formed, the ribbon stock edges 180a, 180b
abut so that edge panels 184a, 184b combine to form the end panel 184. The
fold
lines 182a, 182b, along with fold lines 182c, 182d, define the major panels
186a,
186b. The fold lines 182c, 182d define the end panel 188. The notch 190, shown
in phantom, preferably extends inward from the edge 180a of the ribbon stock
as
illustrated in Figure 3.
Figure 4 illustrates steps in the formation Of tile lnuntill bar M as the
ribbon stock S is progressively folded along the fold lines discussed above.
At the
l0 beginning of the folding process the ribbon stock S is a planar sheet. At
the
conclusion of the folding process, the ribbon stock S has been folded into a
tube
which, in the preferred and illustrated embodiment, has a rectangular cross
section.
With reference to Figures 5 and 6, a muntin bar production line
constructed according to a preferred embodiment of the invention is shown in
somewhat schematic fashion and indicated generally by the reference numeral
100.
The production line 100 comprises a stock supply station 102 from which ribbon
stock S is fed to a first forming station 104, a second forming station 110 to
which
stock from the station 104 is fed and formed into a tube, and a third forming
2o station 112 that severs the tube to form an individual muntin bar. A muntin
bar
handling station, indicated at 114, moves the severed muntin bar to a desired
location. A scheduler/motion controller unit 120 (Figure 6) is preprogrammed
to
control the various stations of the production line 100 in order to govern
muntin
bar size, the stock feeding speeds in the line, activation of the forming
stations,
2 5 and other parameters involved in production.
The Stock Supply Station 102
The stock supply station 102, shown somewhat schematically in Figure 7,
comprises a stock support 106 for the coiled ribbon stock S and a loop feed
sensor
3 0 108. Although coiled ribbon stock is shown, a supply of flat sheets of the
stock
could be used as well. The coiled ribbon stock 121 is painted or otherwise
finished on the side that forms the exterior of the muntin bar and thus must
not
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CA 02550052 1998-02-04
, ' ~ , .
v
be scratched, marred or otherwise damaged during production of the muntin
bars.
The ribbon stock is uncoiled from the support 106 and fed to the loop feed
sensor
108. The ribbon stock support 106 comprises a vertical support column 122
extending upwardly from a base to a stub axle assembly 123 that supports the
coiled stock. The projecting end of the axle assembly 123 that receives the
coil of
stock is provided with a device, e.g., an expandable mandrel (not shown), for
securely clamping the coil. A drive motor and transmission assembly (not
shown)
drives the axle assembly 123 to feed stock from the station 102. The clamping
device is preferably adjustable to receive coils having different widths
depending
1 o upon the size of the muntin bars to be produced by the production line
100.
The loop feed sensor 108 coacts with the controller unit 120 to control the
supply station 102 drive motor to prevent paying out excessive stock while
assuring
a sufficiently high feeding rate through the production line 100. The sensor
108
comprises a stand 150 positioned adjacent the stock support 106, an arcuate
stock
guide 152 for receiving the stock from the support 106, and a loop signal
processing unit 153. Stock fed to the sensor 108 from the support 106 passes
over
the guide 152, droops in a catenary loop 154 and passes over a similarly
configured areuate stack guide 164 (which forms part of a first forming
station,
described below) upon exiting the sensor 108. The depth of the loop 154 is
2 o maintained between predetermined levels by the signal processing unit 153.
The
unit 153 includes an ultrasonic loop detector (not shown) which directs a beam
of
ultrasound against the lowermost segment of the stock loop. The loop detector
detects the loop location from reflected ultrasonic waves and generates a loop
location signal that is transmitted to the controller unit 120.
2 5 If desired, the ribbon stock support 106 may be constructed to permit the
stock to be uncoiled in two different directions, thereby allowing either
surface of
the stock to form the exterior of the muntin bar. For example, the opposite
surfaces of ribbon stock used to form muntin bars sometimes are coated or
painted different colors (or have different patterns). 'The appearance of the
3 o muntin bar formed from such stock depends on the orientation of the stock
when
it is folded into a tubular muntin bar. In Figure 7, the coil of ribbon stock
121 is
rotated to supply the loop feed sensor 108, with the surface of the stock
facing
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CA 02550052 1998-02-04
,
7
upward forming the exterior of the subsequently formed muntin bar. If it is
desired to form a muntin bar in which the exterior is formed by the opposite
surface of the stock, the coil may be removed from the support 106, rotated
180°
about vertical column 122, and then replaced. The coil 121 then is rotated,
with
the opposite surface of the stock now facing upward so as to form the exterior
of
the subsequently formed muntin bar. The station 102 may include suitable
rollers
or other stock guides (not shown) to guide the stock when it is fed in the
opposite
direction from that shown.
1 o The First Forming Station 104
The first forming station 104 is preferably in the form of a material
removal station that receives ribbon stock from the loop sensor 108 and
performs
a precise punching operation on the stock. While the preferred and illustrated
forming tool is a punch unit that forms a notch in the ribbon stock to
facilitate
attachment of the bars to form a grid, it should be recognized that the muntin
attaching or engaging structure could be formed by tools that perform other
processes, for example, drilling, milling, routing, laser cutting, plasma
cutting, etc.,
processes.
In the preferred embodiment, as seen in Figures 8A-8D, the station 104
comprises a supporting framework 160 fixed to the factory floor adjacent the
loop
sensor, and a farming tool in the form of a punch unit 162 carried by the
framework 160. The framework 160 includes a lower section that supports an
upper section on which is mounted a stock guide 164 preferably including a
plurality of rollers. The stock guide 164 supports the stock as it passes from
the
2 5 loop feed sensor 108 onto a ribbon travel path P extending through the
stations
102, 104, 110, 112 and 114. The stock guide 164 is supported by a bracket 166
fixed to the framework 160.
The preferred punch unit 162 comprises a notching assembly 170 and an
actuator assembly, or ram assembly, 172. The notching assembly 170 comprises a
3 o die, or anvil, 174 disposed beneath the stock travel path P. A keeper
plate 174a is
spaced above the upper surface of the die 174 a slight distance and the stock
is
received between the die and keeper plate. A punch, or hammer, 175 is disposed
8
CA 02550052 1998-02-04
above the stock travel path P and is movable toward and away from the die 174
by°
the ram assembly 172. The keeper plate 174a has a recess or open area
configured to, receive the punch 175. The punch 175 includes a portion 175a
having a sharpened edge to punch through the stock,' the edge preferably
having a
slightly chiseled shape; for example, the cutting edge may be offset
21/a° with
respect to horizontal.
A pair of upper and lower punch unit entry guides 176a, 176b are disposed
at the inlet end of the punch unit and are spaced apart to receive the stock.
The
guides 176a, 176b preferably are made of plastic to permit smooth sliding of
the
1 o stock. The lower guide 176b preferably is disposed such that its upper
surface is
located a small distance, e.g., .01", above the upper surface of die 174. An
exit
wear plate 179 is disposed at the outlet end of the punch unit and its upper
surface also preferably is spaced a small distance above the die 174. As a
result,
the stock extends through the punch unit and is supported by the entry guides
176a, 176b and the wear plate 179 so as to be spaced slightly above the die
174 to
prevent damage to the stock finish as it slides through the punch unit. As
such,
the stock, in effect, floats between the die 174 and the punch 175. In
addition,
the lateral edge of the stock opposite the portion punched engages a guide
wheel
178 that includes a V-shaped groove which receives and supports the stock. See
2 o Figures 8A-8D.
The ram assembly 172 is securely mounted atop the framework 160 and
connected to a source of high pressure operating air via suitable conduits
(not
shown). The ram assembly 172 is operated from the controller 120 which outputs
a control signal to a suitable or conventional ram controlling valve
arrangement
2 5 (not shown) when the stock has been positioned appropriately for punching.
The
controller 120 stops the rolling mill to stop the stock feed when the area of
the
stock to be notched is located between the die 174 and the keeper plate 174a.
The ram assembly 172 is actuated and the puncli 175 is driven downward through
the keeper plate and the stock. Upon completion of punching, stock feed
3 0 resumes. When the next location for removing material from the stock
passing
through the line 100 is reached, the stock feed is stopped again and the
punching ,
unit 162 is actuated.
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CA 02550052 1998-02-04
The Second Formin~,Station 110
The second forming station 110 is preferably in the form of a rolling mill
comprising a series of rolls for forming the ribbon stock received from first
forming station 104 into a tube. Figure 4 illustrates schematically the
preferred
manner in which the stock S is folded from its planar configuration by a
series of
steps to form a tube having a desired cross sectional configuration. In the
preferred embodiment, the tube has a rectangular cross section; however, it
will be
recognized that the tube may be various shapes. Thus, different roll
configurations or sizes may be used to vary the shape, height or width of the
l0 finished muntin bar (along with any desired modifications to the process
carried
out by the first forming station 104).
As seen in Figure 4, in the preferred embodiment, the edge panels 184a,
184b are progressively bent upward from the major panels 186a, 186b. The major
panels 186a, 186b then are progressively bent upward toward each other until
the
edges 180a, 180b abut, with the edge panels 184a and 184b combining to form
the
end panel 184. The finished configuration of the tube thus is closed about its
periphery.
In the preferred embodiment, as seen best in Figures 9 and 10, the second
forming station 110 comprises a support frame 200, roll assemblies 201-212
carried
2 0 by the frame, and a drive transmission system for driving the roll
assemblies.
The support frame 200 comprises a base 220 fixed to the factory floor and
a roll supporting assembly 222 mounted atop the base. The base 220 is
positioned
in line with the stock travel path P immediately adjacent the first forming
station
104. Similarly, the roll supporting assembly 222 extends along opposite sides
of
the stock travel path P with the stock travel path P extending centrally
therethrough. The base section 220 comprises legs 224 and support rails 226
extending along opposite lateral sides of the rolling mill at the upper and
lower
ends of the legs 224. The roll supporting assembly 222 supports the roll
assemblies 201-212.
3 o The roll supporting assembly 222 comprises a lower support beam 240 and
an upper support beam 244 each extending along substantially the entire length
of
the rolling mill beneath the roll assemblies 201-212. A series of spaced apart
CA 02550052 1998-02-04
j
vertical. upwardly extending stanchions 242 are fixed to the beams 240 and
244,
one pair of vertically aligned mill rolls being received between each
successive pair
of the stanchions 242. 'The upper support bar 244 is illustrated as being
fixed to
the stanchions by heavy machine screws, but nuts and bolts could also be used.
Each pair of rolls extends between a respective pair of stanchions 242 so that
the
stanchions provide support against relative roll movement in the direction of
the
stock travel path P. The stanchions 242 also secure the rolls together for
assuring
adequate engagement pressure between the rolls and stock passing through the
roll nips.
1 o In the preferred embodiment, each roll assembly 201-212 is formed by a
pair of vertically aligned upper and lower rolls that define a single "pass"
of the
rolling mill. Each roll assembly 201-212 comprises a bearing housing 260,
upper
and lower roll shafts 262, 263 extending through a bearing in the housing 260,
and
upper and lower stock forming rolls 264, 265 respectively disposed on the
inwardly
projecting ends of the shafts 262, 263. The bearing housings 260 are captured
between, adjacent stanchions 242. Drive pulleys or sprockets 266, 267 are
respectively disposed on the ends of shafts 262, 263 disposed at the rear of
the
rolling mill (Figure 10) and project laterally outwardly from the support
unit.
One or more guide rolls, indicated in phantom at 268, may be provided
2 o adjacent the forming rolls of one or more passes of the rolling mill to
ensure the
ribbon stock is moved through the roll nips without bending or kinking. The
guide rolls preferably are disposed between selected adjacent passes of the
rolling
mill to support the stock as it extends between the passes. The guide rolls
may be
disposed in pairs, i.e., one roll on each side of the stock travel path P
between
adjacent passes of the mill to engage both sides of the stock, or a single
guide roll
may be provided between adjacent passes to engage only one side (preferably
the
side that is notched) of the stock. It should be recognized that whether the
use of
guide rolls 268 is desirable or necessary will depend upon various factors
such as
the width of the stock, the thickness of the stock, and the type and strength
of the
3 o stock material. Thus, the guide rolls may be useful in some applications
but not
others.
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CA 02550052 1998-02-04
The upper support beam 244 of the roll supporting assembly carries a nut
and screw adjustment mechanism 270 associated with the upper roll of each roll
assembly 201-212 for adjustably changing the position of the upper roll. The
lower roll 265 of each roll assembly is fixed in position on the lower support
beam
240. The mechanism 270 comprises a screw 272 threaded into the upper roll
bearing housing 260 and a lock nut 273 engaging the screw. The nut 273 is
rotated to move its associated screw 272 and positively adjust the position of
the
bearing housing 260 and the upper roll 264 relative to its corresponding lower
roll
265. The adjustment mechanisms 270 enable the upper roll in each roll pair to
be
1o moved toward or away from the lower roll which also increases or decreases
the
pressure that the rolls exert on the stock.
The rolling mill is provided with a drive transmission system for rotating
the rolls. The preferred and illustrated drive transmission system comprises a
motor driven chain and sprocket assembly; however, it will be appreciated that
other drive systems may be used, e.g., a system employing gears, belts, etc.
The drive transmission system includes a motor 213 fixed to the support
rail 226 of base 220 by any suitable means. The motor 213 is preferably an
elec-
tric servomotor driven from the controller unit 120. As such, the motor speed
can
be continuously varied through a wide range of speeds without appreciable
torque
2 o variations. The motor 213 is preferably disposed on' its side with its
output shaft
extending horizontally and laterally relative to the stock travel path P. The
motor
213 is coupled to the roll assemblies 201-212 so that the roll assemblies are
positively driven whenever the servomotor is operated.
Referring to Figure 9, the motor output shaft drives a sprocket 214 which
2 5 in turn drives a chain 215 to rotate a sprocket fixed to a shaft 216
disposed
beneath the inlet end of the rolling mill. A secondary drive chain 217 is
reeved
around another sprocket fixed to the shaft 216 and also around the sprockets
266,
267 of the rolls in each assembly 201-212 (as well as a pair of idler
sprockets 218,
219). One or more of the sprockets may be adjustably mounted to the frame to
3 o adjust the tension in the chains 214, 217, for example, by brackets that
are slidable
along the frame and fixed at a desired position.
12
CA 02550052 1998-02-04
Accordingly, whenever motor 213 is driven, the rolls 264, 265 of each roll
assembly are positively driven in unison. The rolls in each assembly 201-212
are
driven so as to have the same surface speed. In addition, the speed of the
rolls
increases by a slight amount progressing from assembly 201 to assembly 212
which
serves to slightly tension the stock being pulled through the rolling mill.
The forming rolls 264, 265 of roll assemblies 201-212 are configured to
progressively form the ribbon stock from its planar configuration into a tube
which, in the illustrated embodiment, has a rectangular cross section. The
first
three passes of the rolling mill, i.e., roll assemblies 201-203, bend the edge
panels
184 upward about fold lines 182a (Figures 3 and 4). The roll assemblies 204-
212
then progressively bend the major panels 186a, 186b upward until the edges
180a,
180b meet to form a tube closed about its periphery. The tube formed by the
second forming station 110 has one or more notches 190 precisely located at
predetermined locations. It should be appreciated that the number of forming
roll
assemblies and the configuration of the forming rolls may be varied from that
. shown in the drawings, for example, in order to produce tubes having
different
configurations.
The Third Forming Station 112
2 0 The third forming station 112 preferably is in the form of a severing
station
that severs the tube exiting the forming station 110 into an individual muntin
bar.
In the preferred embodiment, as seen in Figures 11A-11C, the station 112
comprises a frame 302 that is fixed to the factory floor adjacent the forming
station 110 and supports a platform 304. The platform 304 is disposed
alongside
2 5 the forming station 110 at a height that permits the tube exiting the
station 110 to
slide above the upper surface of the platform 304. The platform includes a
slot
306 through which a cutting device passes in order to cut the tube as the tube
rests at a height so as to not contact the platform (in order to prevent
damaging
the finish).
3 o In the illustrated embodiment, the cutting device is a circular saw blade
308
attached to a sprocket that is rotated by a belt 310 driven by a sprocket 312
connected to the output shaft of a motor 314. It should be recognized that
other
13
CA 02550052 1998-02-04
s
. i
cutting devices and/or drive mechanisms could be utilized to sever the tube
formed
by the station 1I0. The particular characteristics of the saw blade, e.g., the
material forming the blade, the size of the blade, the number and shape of the
cutting teeth, etc., may vary depending upon the size of the tube and the
material
forming the tube. For example, one type of blade may be used to sever steel
bars
and a different blade used to sever aluminum bars.
The saw blade 308, belt 310, sprocket 312 and motor 314 are mounted to a
plate or arm 316 that is pivoted at one end 318 to a bracket fixed to the
underside
of the platform 304. The opposite end 320 of the arm 316 is attached to a
z0 pneumatic actuator 322 that is secured to the frame 302. Upon receiving an
appropriate control signal from the controller 120, the actuator 322 raises
the arm
316 with respect to the platform 304 such that the rotating saw blade 308
passes
through the slot 306 in the platform and into cutting engagement with the tube
T.
After cutting the tube T, the actuator 322 lowers the arm 316 and saw blade
308
so that the tube formed by station 110 can slide along the platform 304. As
indicated schematically in the Figures, a valve is provided to control the
actuator
322 in order to control the speed at which the saw blade is moved into the
tube.
The valve controls operation of the pneumatic actuator upon receiving command
signals from the controller 120.
2 o A rod 324 is fixed to the platform 304 and the arm 316 to limit movement
of the arm in the downward direction. In the illustrated embodiment, the rod
324
has a nut 326 threaded on its end to abut the arm 316 in its lowered position.
Another nut preferably is provided on the rod 324 to abut the arm in its
raised
position. It should be recognized that mechanisms other than that illustrated
could be used to limit movement of the arm 316.
A clamping mechanism 330 is provided on the upper surface of the
platform 304 to hold the tube in position to be cut by the saw blade 308. The
mechanism 330 comprises a fixed clamp member 332 and a movable clamp
member 334. An actuator 336 is secured at an end 338 to the platform and
3 o attached at an opposite end 340 to the movable clamp 334. The clamp
members
332, 334 have slots or grooves passing through a portion of their height and
the
saw blade 308 passes through such grooves upon being raised by the actuator
322.
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CA 02550052 1998-02-04
1
:..w~
The tube exits the station 110 and slides next to (preferably without
contacting)
the fixed clamp member 332: When the tube has moved along the stock travel
path such that the area of the tube to be cut is located above the slot 306 in
the
platform 304, the actuator 322 moves the saw blade 308 upward to sever the
tube
to form a muntin bar having a desired length. The slots are preferably formed
in
the middle area of the clamp members 332, 334 so that the tube is supported on
both sides of the cut made by the saw blade 308.
The Muntin Bar Handlin,.g, Station 114
to The invention includes a muntin bar handling station fox receiving the
muntin bar exiting the third forming station 112 and moving the bar away from
the stock travel path P. This permits subsequently formed muntin bars to exit
the
third forming station and also may serve to sort and move the muntin bars to a
desired area (not shown).
z 5 In the preferred embodiment, as seen in Figures 12A-12C, the muntin bar
handling station is indicated generally by reference numeral 114 and comprises
a
conveyor to move the muntin bars away from the stock travel path P. The
illustrated conveyor comprises a frame 310 with posts 312 and rails 3I4
supporting
a plurality of conveyor belts 316 that extend across the upper portion of the
2 o conveyor frame, the belts 316 being reeved around sprockets or pulleys 318
rotatably mounted to the frame. A motor 320 drives a gearbox 322 and a drive
belt 326 that rotates a drive shaft 324, which in turn rotates the sprockets
318 to
drive the conveyor belts 316. The conveyor belts 316 carry grasping elements
of
some form to engage the muntin bar. In the preferred embodiment, the elements
25 are hooks 328 extending from the surface of the belts 316. As the belts are
driven
in a direction transverse to the stock travel path, the hooks 328 pick up a
muntin
bar that has been severed at the station 112 and carry it away from the stock
travel path P. It should be recognized that devices other than that
illustrated may
be used for handling the muntin bars exiting station 112.
3 o The muntin bar handling station 114 may be provided with an optional
adhesive applicator for applying a suitable adhesive material to the notches
in the
individual muntin bars. An adhesive applicator indicated by reference numeral
CA 02550052 1998-02-04
y.
330 is shown schematically and preferably comprises a track or guide 332 and
an
applicator head movably mounted on the track. The applicator 332 is moved
along the track to overlie the notches formed in the individual muntin bars
being
carried by the conveyor belts 316 and is activated to deposit adhesive in the
notches. Any suitable means fox moving the adhesive applicator along the track
may be used, for example, a rack and pinion drive, a belt drive, a lead screw
assembly, etc.
The Controller Unit 120
1 o In the preferred embodiment of the invention, the controller unit 120
comprises a personal computer having a display monitor, an operator accessible
keyboard, and a central processing unit (CPU) which governs operation of the
production line 100. The CPU includes a programmable microprocessor that
executes a control program containing a schedule of operations to be performed
to produce a batch of individual muntin bars suitable for subsequent assembly
into
a grid. The microprocessor controls feeding the stock from supply station 102,
and processing of the stock at stations 104, 110, 112 and 114. Figure 6 shows
schematically a link or line of communication between each of the various
stations
and the controller 120. The control program thus dictates the production
2 0 schedule of the muntin bars manufactured by the production line 100.
Accordingly, when the muntin bars for a given size insulating glass unit,
such as the unit 10 of Figure l, are to be produced, the ribbon stock is fed
from
supply station 102 and a signal is generated by the loop feed sensor 108 and
transmitted to the controller unit 120. The controller unit 120 speeds up,
slows or
2 5 stops the supply station motor depending on the condition of the stock
loop at the
sensor 108. However, once the production line 100 is in operation, feed of
stock
through the production line generally is governed by the controller stopping
or
activating the rolling mill.
The stock passes through the first forming station 104 with the controller
3 0 120 monitoring the feed rate of stock. The controller 120 stops the
rolling mill
during activation of the punching unit 162. The punching unit 162 is provided
with a sensor (not shown) that detects when the punch 175 has been raised to
its
16
CA 02550052 1998-02-04
y
upper position, and a sensor (not shown) that detects when the punch 175 has
been lowered to its lower position. After the unit receives a punch command
from the controller 120, the sensors detect whether the punch has reached its
lower position and then raised to its upper position. If so, the rolling mill
is
activated to resume feeding the stock through the production line. If not, the
rolling mill is not activated.
After the stock has been punched as detected by the sensors, operation of
the rolling mill resumes and the notched stock passes through the mill and is
formed into a tube. The tube exits through the nip between the rolls of the
final
1o roll assembly 212 (i.e., the final pass of the rolling mill) and engages a
sensor, e.g.,
rotary encoder 300. The encoder 300 has a roller with a frictional outer
surface
and is rotated upon being contacted by the tube exiting the rolling mill. A
pair of
V-shaped rollers are preferably disposed above the encoder roller so that
substantially equal pressure is applied to the top and bottom of the tube
exiting
the station 110.
The encoder 300 generates a signal that is transmitted to the controller 120
indicating the position of the tube passing through the rolling mill, as well
as the
position of the ribbon stock passing through the punching unit. This
information
is used to control movement of the stock through the production line 100 to
2 o ensure that the notches are properly located in' the stock, and that the
third
forming station 112 cuts the tube at correct locations to produce individual
muntin
bars having a correct length. The encoder 300 transmits a signal that
correctly
indicates the position of stock in the line even if slippage in the line
occurs, due to
the encoder signal being generated by physical contact with the tube.
2 5 The controller 120 controls the third forming station 112 to sever the
tube
into an appropriately sized individual muntin bar. When the tube is in
position at
the station 112, the saw is moved upward through the slot 306 in the platform
304
and severs the tube. A first sensor (not shown) is located beneath the
conveyor
belt adjacent the station 112 and detects whether the severed muntin bar is in
a
3 o payout position, a position where the bar needs to be removed from station
112 by
the conveyor. If the bar is in such a payout position, the controller stops
the
rolling mill to prevent a tube being formed and fed to the station 112 before
the
17
CA 02550052 1998-02-04
severed muntin bar has.been removed by the conveyor. A second sensor (not
shown) is mounted beneath the conveyor belt adjacent the station 112 and
detects
whether the conveyor belts are in a position so that the hooks 328 will engage
the
severed bar upon actuation of the conveyor. If the belts are not in proper
position, the rolling mill is stopped and not activated until the belts have
been
moved to a muntin bar engaging position. A third sensor (not shown) is mounted
beneath the conveyor belt adjacent the end of the conveyor disposed away from
the stock travel path P and detects whether the conveyor is fully loaded with
muntin bars. I~ such condition is detected, the rolling mill is stopped until
at least
1o some of the muntin bars are removed from the conveyor belts. The conveyor
may
be operated to perform various functions, for example, carrying the muntin
bars to
another location (not shown) where they are assembled into a grid for use in
an
insulating glass unit, or carrying the muntin bars to one of different storage
locations where they are stored according to their size, color or finish, etc.
If the production line is provided with an adhesive applicator for applying
adhesive to the notches in the muntin bars, the controller 120 is used to
control
movement of the applicator head along the track as well as activation of the
head
to deposit adhesive in the notches.
The controller 120 may carry out a computer integrated manufacturing
2 o scheme that automatically produces muntin bars according to pre-programmed
or
custom programmed production schedules.
Alternative Embodiments
Referring to Figures I3-15, an alternative embodiment of the second
forming station 110 is shown and includes an adjustment mechanism for
adjusting
the roll assemblies to enable the station 110 to roll form different width
ribbon
stock. The rolling mill of this illustrated embodiment includes ten roll
assemblies
201-2I0; however, it should be recognized that it may include twelve
assemblies as
in the previous embodiment, or any other number of assemblies depending upon
3 o the particular application. The portion of the rolling mill comprising
roll
assemblies 201-203 in this embodiment is separate from the portion comprising
roll assemblies 204-210. The roll assemblies 201-203 in this embodiment
comprise
18
CA 02550052 1998-02-04
1, , side-by-side roll assemblies 202a-203a and 201b-203b that are movable
toward and
away from each other.
The base portion of the rolling mill frame may be viewed as comprising a
section 220 which extends beneath roll assemblies 204-210, and a section 230
which extends beneath roll assemblies 201-203 and comprises legs 234 and
support
rails 236. Similarly, the roll supporting frame assembly may be viewed as
comprising a section 222 which extends beneath roll assemblies 204-210, and a.
section 232 which extends beneath roll assemblies 201-203. The construction of
the rolling mill section comprising roll assemblies 204-210 is as described
above in
1o connection with the preferred embodiment.
The roll supporting frame section 232 extending beneath roll assemblies
201-203 comprises two roll supporting portions disposed side-by-side in
essentially
parallel fashion. These two roll.supporting portions include lower support
beams
250a, 250b and upper support beams 254a, 254b, with two series of spaced apart
vertical stanchions 252a, 252b respectively disposed therebetween. Each roll
assembly 201-203 includes two side-by-side pairs of vertically aligned rolls,
one
pair received between the stanchions in each series. The roll pairs of the
respective roll assemblies 201-203 comprise bearing housings 260a, 260b, upper
and lower roll shafts 262a, 262b extending through a corresponding bearing
2 0 housing, upper stock forming rolls 264a, 264b on the inwardly projecting
ends of
the upper roll shafts, and lower stock forming rolls 265a; 265b on the
inwardly
projecting ends of the lower roll shafts. A drive pulley 266a is disposed on
the
outboard ends of each shaft 262a, while a drive pulley 266b is disposed on the
outboard ends of each shaft 262b. The bearing housings 260a, 260b are provided
2 5 with a roll position adjustment mechanism, constructed in accordance with
the
mechanism 270 described above.
The two side-by-side portions of roll supporting frame section 232 are
movable toward and away from each other to vary the spacing between the
adjacent roll pairs of each roll assembly 201-203. In particular, the roll
pairs 201a-
3 0 203a carried by beam 250a, stanchions 252a and support bar 254a and the
roll
pairs 201b-203b carried by beam 250b, stanchions 252b and support bar 254b are
movable in a lateral direction toward or away from each other. The roll
19
~ CA 02550052 1998-02-04
a
' 1
L ..v' ,
supporting assembly 232 is provided with transverse beam-like trackways 238
extending between the rails 236 at locations spaced apart along the stock
travel
path P to facilitate lateral adjustment of roll assemblies 201-203. A network
of
stiffening elements (not shown) interconnects the rails 236, trackways 238 and
legs
234.
An actuating assembly, indicated at 275, is provided to move the roll
assemblies 201a-203a toward or away from 201b-203b. The assembly 275 includes
a base 276 that carries spaced apart linear bearings 277 which slide along the
trackways 238 so that the beams 250a and 250b move laterally toward and away
to from the stock travel path P. The actuating assembly 275 comprises a
jackscrew
280 having right and left hand threaded sections extending between lateral
sides of
the roll supporting frame section 232, and a drive transmission 282 attached
to the
jackscrew. The jackscrew is mounted in bearings fixed to the rails 236 with
its axis
of rotation extending laterally across the rolling mill. The lower support
beams
250a, 250b disposed on opposite sides of the stock travel path P are
respectively
threaded onto the right and left hand jackscrew threads. As such, when the
. jackscrew 280 is rotated, e.g., by hand crank 282, the beams and their roll
pairs
are moved laterally toward each other, while jackscrew rotation in the
opposite
direction moves the roll pairs away from each other. The beams 250a, 250b move
2 o along the trackways 238 with the aid of the linear bearings 277 during
their
position adjustment: The drive transmission 282 is preferably a hand crank
although other drive mechanisms may be used.
The second forming station embodiment of Figures 13-15 includes a drive
transmission assembly which is similar to that described above in connection
with
2 5 the first embodiment. However, in this embodiment separate drive
transmission
assemblies are provided for driving the roll pairs of assemblies 201a-203a and
201b-203b. As seen in Figure 15, which shows the rear of the rolling mill, the
main drive transmission assembly comprises a motor 213 disposed on the rear
side
of the rolling mill, and a sprocket 214 rotated by the motor. A main drive
chain
3 0 215 passes around the sprocket 214, a pair of drive sprockets 216, and an
idler
sprocket disposed intermediate the sprockets 216. The sprockets 216 axe
attached
CA 02550052 1998-02-04
to a pair of shafts extending across the rolling mill'which rotate upon
actuation of
the motor 213.
Figure 15 also shows the drive fox the roll assemblies 201b-203b, which
comprises a secondary drive chain 217b that passes around two sprockets 216b
respectively fixed inwardly on the two shafts on which the sprockets 216 are
fixed.
The drive chain 217b also passes around a paix of idler sprockets 218b, as
well as
the sprockets 266b, 267b carried by the upper and lower rolls of each roll
assembly 201b-203b. Thus, rotation of the sprockets 216 via motor 213 and main
drive chain 215 rotates secondary drive chain 217b via sprockets 216b to
rotate the
1o rolls 264b, 265b of each assembly 201b-203b.
Referring to the front side of the rolling mill as seen in Figure 13, which
shows the drive for the roll assemblies 201a-203a, another secondary drive
chain
217a passes around two sprockets 216a respectively fixed to the two shafts on
which sprockets 216b are fixed. The drive chain 217a also passes around a pair
of
idler sprockets 218a, as well as the sprockets 266a, 267a carried by the upper
and
. lower rolls of each roll assembly 201a-203a. Thus, rotation of the sprockets
216
via motor 213 and main drive chain 215 also rotates secondary drive chain 217a
via sprockets 216a to rotate the rolls 264a, 265a of each assembly 201a-203.
The rolls of roll assemblies 204-212 are driven upon actuation of the motor
2 0 213 via another secondary drive chain 217c (Figure 15). The drive train
217c
passes around one of the sprockets 216b (the one disposed under roll assembly
204) and idler sprocket 219, and the sprockets 266, 267 of roll assemblies 204-
210.
As such, upon actuation of motor 213 the drive chain 217c rotates the rolls
264,
265 of assemblies 204-210 in unison with the rolls of assemblies 201-203. It
should
2 5 be noted that while the embodiment of Figures 13-15 is illustrated as
including ten
roll assemblies, it could include more or less than ten.
In the embodiment with an adjustable rolling mill the rolls of roll
assemblies 201-203 are movable laterally toward or away from each other to
accommodate different width ribbon stock. The size of the edge panels 184a,
3 0 184b (and central panel 188) typically are the same for different size
muntin bars.
In other words, referring to Figure 2, it is the dimension of major panels
186a,
186b that varies between different width muntin bars. Accordingly, adjusting
the
21
CA 02550052 1998-02-04
. .c
' ' '
position of the roll assemblies 201-203 accommodates different size ribbon
stock
by varying the distance between the fold lines 182a and 182c, and 182b and
1$2d
of the stock (Figures 3 and 4).
The first forming station 104 preferably is designed to remove material
from the midpoint of the ribbon stock regardless of the distance from the
midpoint of the stock to the edges 180a or 180b. Thus, the same mechanism,
e.g.
punching unit 162, removes the correct amount of material for different widths
of
sheet stock in the embodiment of Figures 13-15.
Figures 16 and 17 show an alternative construction for a ribbon stock
to support 106a that may be used in lieu of the support 106 discussed above in
connection with the supply station 102. The support 106a comprises a caster
mounted support dolly 130 having a vertical support column 132 anchored to it
and extending upwardly to a coil support unit. The coil support unit comprises
a
support housing 136 mounted on the column 132 by a bearing (not shown) which
enables the housing to be rotated relative to the column and dolly about a
vertical
axis 138 extending through the column in order to adjust the position of the
coil.
A coil-supporting stub axle assembly 140 projects from the housing 136 to
support
each coil of stock material.
Each axle assembly 140 is provided with an expandable mandrel 142 at its
2 o projecting end on which the coil is received. A drive motor 144 drives
each aide
assembly 140 to feed stock from the station 102. A drive transmission (not
shown) within the housing 136 couples the motor to its driven axle. The
expandable mandrel 142 is adjustable to receive coils having different widths
depending upon the size of the muntin bars being produced by the production
line
100. The housing 136 is rotated about the bearing axis 138 to place one coil
in
reserve and position a second coil for feeding the production line. A suitable
latching mechanism may be provided to lock the housing 136 in place when a
coil
has been positioned for supplying stock to the line. When stock from the one
coil
is required for production, the latching mechanism is operated to free the
housing
3 0 136 for rotation about the axis 138 to bring the one coil into position
for feeding
the line. The latching mechanism is then operated to lock the housing in
place.
The motor 144 is an electrically powered A.C. motor (power lines axe not
22
CA 02550052 1998-02-04
.. . .
illustrated) which positively drives and brakes the axle assembly under
control of
the controller unit 120. 'The dolly 130 engages a floor mounted stop bracket
I47
when positioned fox feeding stock so that the feed coil is positively
positioned
during muntin bar production.
During the time stock is payed off of one coil for producing muntin bars,
the other coil may be replaced, if desired, to provide another width of stock
material which can be held in reserve until needed. Alternatively, the support
106
may be used to feed stock for producing only one size muntin bar, the second
coil
serving as a reserve supply of stock to reduce system downtime upon reaching
the
l0 end of the first coil.
As described above, the invention is preferably used to form muntin bars
from ribbon stock that is notched while in its planar condition and then
formed
into a tube that is severed to form an individual muntin bar. However, it also
is
possible to modify the invention to form muntin bars from ribbon stock that is
first formed into a tube and then notched.
In this embodiment of the invention, the first forming station I04 is
omitted and the ribbon stock is fed from the loop feed sensor 108 into the
second
forming station 110. The third forming station preferably is modified as
illustrated
in Figures 18A-IBC. The station, indicated by reference numeral 412, includes
a
2 0 punch unit 420 constructed to form a notch in the tube that exits the
third forming
station 110. As described above with respect to the first forming station 104,
alternative mechanisms may be used to notch or otherwise process the tube to
include muntin bar engaging structure, for example, broaching, swedging,
routing,
shearing, etc., processes.
2 5 The modified forming station 412 includes a platform 414 and a severing
mechanism indicated generally by reference numeral 416 which is constructed in
accordance with the above description of forming station 112. The punch unit
420
includes a ram assembly 422 that drives a member 424 attached to a punch 426.
The punch 426 has a sharpened chisel-shaped edge configured to drive through
3 o the tube T to remove a portion of the tube and form a notch 190 such as
that
described above in connection with Figure 2. The punch unit comprises a punch
23
. CA 02550052 1998-02-04
guide block 428 that is provided with a vertical punch bore 430 through which
the
punch 426 passes.
A tube receiving recess 432 if formed in the punch guide block 428 and
extends horizontally across the face of the block and intersects the punch
bore
430. When the tube T is inserted into the recess 432 it extends into the punch
bore 430 a depth of about one-half the thickness of the tube. A clamp member
434 is movable upon actuation of a cylinder 436 to clamp the tube within the
recess 432 during the punching operation.
The ram assembly 422 receives command signals from the controller 120 so
30 that when the portion of the tube T to be notched is located in the recess
432 and
beneath the punch 426, the rolling mill is stopped and the ram assembly 422 is
activated to drive the punch down through the tube T.
While the invention has been described in detail with respect to the
preferred embodiments thereof, those skilled in the art will appreciate that
many
changes and modifications may be made thereto without departing from the
spirit
or scope of the invention as defined in the claims.
24
