Note: Descriptions are shown in the official language in which they were submitted.
CA 02310993 2006-08-30
System for Fabricating Contour Muntin Bars From Sheet Material
10
Field Of The Invention
The present invention relates to the fabrication of insulating glass units
for windows, and more particularly to a system for fabricating muntin bars
used in the construction of insulating glass units.
Background 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
that are associated with architectural styles of buildings containing the
windows.
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 from decoratively coated
interfitted metal tubes. The grids are 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
CA 02310993 2000-06-08
have been made. For example, machines for notching lengths of preformed
tubular muntin bar stock
at predetermined locations have been proposed. The muntin bar stock is cut
into lengths for use in
forming a grid for a given size insulating glass unit. The cut rriuntin 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 respective muntin bars at the
notches.
The muntin bar stock is produced by roll forming decoratively coated sheet
material such as
aluminum or steel, in a known manner. Various sizes of the sheet material are
used to form different
size muntin bar stock. The roll forming 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
effciency. 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 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
2o cut-to-Ieno h 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 machinery may be
specialized to notch the
bars for forming rids, the muntin bars typically must be manually handled 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 fabricating
steps, thereby increasing the
di~culty and cost associated with such construction. The handling and notching
procedures may also
result in damage to the muntin bar finish and denting, or creasing.
The present invention provides a new and improved system for fabricating
muntin bars which
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is so constructed and arranged that muntin bars are quickly and eff ciently
formed from sheet material,
notched or otherwise formed to permit subsequent attachment in a grid, and
then cut to length
without requiring significant handling or mentation on the part of the
individual fabricating the muntin
bars. The invention provides a method and apparatus for continuously producing
notched muntin
bars from sheet stock; thus, a manufacturer is able to store coils of sheet
material rather than a supply
of precut tubular muntin stock. Also, production of the muntin bars is
automatically controlled to
allow muntin bars to be custom formed for specific orders.
Summary of the Invention
The present invention concerns method and apparatus for making a contoured
muntin bar.
A strip of sheet material having a finished surface on at least one side is
unwound from a supply and
fed along a strip travel path to a punch station. At the punch station a
ribbon punching mechanism
punches the ribbon at a precisely predetermined locations along the ribbon to
form one of a plurality
notch patterns that define a portion of a contoured muntin bar.
Downstream from the punch station the ribbon is fed through a forming station
having a
succession of forming rolls that bend the ribbon and form a'generally closed
cross-sectional tube. The
rolls bend the strip in stages to produce a muntin bar tube having a contoured
shape with raised sides
that provide an attractive appearance to the muntin grid made from the
contoured muntin bars.
The closed cross-section tube is routed from the forming station to a cutting
station. At the
cutting station an endmost muntin bar is cut from the tube at a precisely
predetermined location by
cutting the tube along a cut line that is defined by the notch patterns.
Sensors monitor the progress
of the fabrication of muntin bars and communicate the sensed status to a
programmable controller
which co-ordinates all processing steps.
A second of the notch patterns creates a mitred end to the muntin bars. In
response to sensing
a notch pattern for forming a mitred bar end, the controller initiates the
clamping an end of the muntin
tube prior to severing an endmost muntin bar. After the severing step, the
severed muntin bar is
moved away from the muntin tube to which it was previously attached to widen a
gap between the
severed muntin bar and the muntin tube. The mitred ends of the severed muntin
bar and the muntin
bar tube that are spaced apart by the gap are then finished by moving a high
speed router bit specially
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configured to shape the ends through this widened gap.
After an endmost bar is severed the process has produced a tubular muntin bar
made up of
an elongated tube having two mitred ends, two flat ends'or one mitered end and
one flat end. The
mitred ends include muntin bar portions that fit over mid portions of other
muntin bars to form a part
of a grid. The flat ends form outer bounds of a completed muntin bar grid for
contacting a window
spacer frame.
The cross section of a completed muntin bar defines a perimeter that encloses
an area
having the general shape of a cross. The cross-shaped area defined by the
perimeter of the
formed muntin bar has two relatively narrow top and bottom legs and two
relatively wide side
to legs. The length of the top and bottom legs is the same and the length of
the two side legs is the
same. The width of each leg tapers down along its length. A seam is formed at
the end of one of
the legs where two edges of the material used to form the tube meet. No
welding of the seam is
required after severing of the muntin bar. The severed bar can immediately be
assembled into an
attractive ready to install muntin bar grid.
1 s Practice of the invention results in faster production of contoured muntin
bars when
compared to prior art production speeds. Using the apparatus and method of the
disclosed
invention, one person can make and assemble 1000 grid units during an eight
hour shift compared
to approximately 200 units when using fabrication techniques of the prior art.
The cost per foot
of muntin bar produced is also lower. The cost in making the contoured muntin
bars using the
2o invention is less than half the cost of making them with prior art
apparatuses and the quality is
better. More specifically, the invention produces higher quality, virtually
seamless bars with
precision cuts where the bar engages the window spacer frame and miters the
muntin bars where
they engage cross bars of the grid. The invention facilitates "just in time"
manufacturing since the
bars that make up a grid can be programmed into a controller and produced by
the operator as
2S other grids are being made. The controller optimizes the use of materials.
The controller makes
muntin bars for each grid in turn and then begins producing muntin bars for a
subsequent grid
based on a program of jobs programmed by the iser. Excess payout of strip
material is avoided
and practice of the invention has reduced scrap material by at Ieast 10
percent.
These and other objects, advantages and features of the invention will become
better
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understood from the detailed description of a preferred embodiment of the
invention which is
described in greater detail in conjunction with the accompanying drawings.
Brief Description of the Drawings
Other features and advantages of the invention will become apparent from 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 in accordance with the invention;
1o Figure 2A is an enlarged perspective view of an intersecting portion of the
muntin bar grid
of the insulating glass unit of Figure 1;
Figure 2B is an enlarged perspective view of the intersecting portion shown in
Figure 2A with
one bar disengaged from a transversely extending bar to show an
interconnecting clip;
Figure 3 is a perspective view of a portion of sheet or stock material
partially processed
15 according to the invention;
Figure 4 is an elevation view schematically illustrating different roll stages
during roll forming
of the stock material of Figure 3 into a contoured tubular muntin bar;
Figure 5A is an elevation view showing a muntin bar production line
constructed according
to the invention;
20 Figure SB is a plan view of the muntin bar production line of Figure SA;
Figure 6 is a schematic depiction of a completed muntin bar grid showing the
locations for
mitred and flat muntin bar ends of the muntin bars forming the grid;
Figure 7 is a perspective view of a control unit that co-ordinates the
fabrication steps
performed along the production line as the muntin bars are fabricated;
25 Figure 8 is a perspective view of a muntin bar having a mitred end;
Figures 9A and 9D are a series of plan views showing steps of severing of a
muntin bar from
an end of a strip of stock material and then finishing a mitred end of said
severed muntin bar;
Figure 10 is a perspective view of a rower bit used to perform a finishing
step on mitred
muntin bar ends;
CA 02310993 2000-06-08
Figure 11 is a perspective view of a punching station that notches the sheet
material; Figure
12 is a perspective, exploded view of a sever/finish station of the production
line;
Figure 13 is a perspective view of the sever/finish station;
Figure 14 is a perspective view of a tubular muntin bar showing a manner in
notch patterns
are detected prior to severing an endmost muntin bar;
Figure 15 is a perspective view of a sequence of multiple roll assemblies that
make up a
muntin bar forming station;
Figures 16A, 16B, and 16C show conforming roller surfaces of three
representative roller
assemblies; and
Figures 17A and 17B are elevation and plan views of a portion of a drive
transmission for the
roller assemblies that make up a second forming station.
Detailed Description of Preferred Embodiments
Figure 1 shows an insulating glass unit indicated generally by the reference
numeral 10
comprising a spacer assembly 12 sandwiched between glass sheets, or lights,
14. The spacer
assembly I2 includes a frame assembly 16 hermetically joined to the glass
lights by a sealant 18 to
form a closed dead air space 20 between the lights. The unit 10 is illustrated
in Figure 1 in
condition for assembly into a window or door frame (not shown).
A muntin bar grid G is disposed between the glass lights to provide the unit
10 with the
appearance of a multi-pane window. Depending on the size of the glass sheet
mounted in the
spacer assembly the grid G can subdivide the glass sheet into different number
of segments or
panes. The light illustrated in Figure 1 has been divided into four different
panes, but many other
configurations of muntin bar grids for dividing the lights into other numbers
of panes is possible.
The muntin bars depicted in Figures 1, 2A, and 2B are contoured muntin bars.
Such a
muntin bar presents a more appealing appearance than the rectangular cross
section muntin bar
disclosed in parent application serial number 08/797,031. As seen in the views
of Figures 2A and
2B an interior region of the bars is hollow and the sheet material used to
construct the muntin bar
.. ~s
is bent as described below to be symmetric on opposed sides of transverse axes
A1, A2 that
intersect four generally flat surfaces S 1 and S4. The two surfaces designated
S 1, S3 in Figure 2A
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are side surfaces and the two surfaces designated S2, S4 are top and bottom
surfaces.
Interconnecting the planar surfaces S 1, S2 are two beveled surfaces B 1, B2.
Figure 2A illustrates a grid G for dividing the light into four panes. As'seen
in Figure 2B a
first elongated muntin bar 22 extends across a width of the window. Attached
to a middle region
23 of the bar 22 are two shorter transversely extending bars 24, 26. The two
shorter bars 24, 26
are connected to the elongated muntin bar 22 by means of a muntin clip 26
(preferably
constructed from plastic) that extends through the middle region 23 of the bar
22. When the clip
is attached to the muntin bar 22, it extends beyond the two sides S2, S4 of
the bar 22 so that the
two transverse muntin bars 24, 26 can be attached to the clip. During
fabrication of the grid G
from its constituent muntin bars 22, 24, 26 one end of the clip 28 is inserted
into one of two
elongated side slots 30 in the bar 22 and is pushed through the elongated bar
22 so that the end of
the clip first inserted into the bar 22 exits a similar slot 30 formed in an
opposite side surface S2
of the bar 22. For the clip to extend through the slots 30 a flexible tab 32
that normally extends
downwardly (as seen in Figure 2B) is flexed away from its normal configuration
so that the clip
28 can be pushed through the muntin bar 22. When the clip has been pushed
through the bar the
tab 32 snaps back to its unflexed position and overlies the surface S2 to
prevent the clip from
sliding back into the bar 22. Additional details of the clip 28 are disclosed
in co-pending United
State patent application serial number 09/233,834 filed January 20, 1999
entitled "Muntin Grid
Joiner" which is assigned to the assignee of the present invention and which
is incorporated herein
by reference.
Flat ends F of the muntin bars that make up the grid G are secured to the
interior of the
spacer frame assembly 16 by suitable fasteners as are known in the art.
Opposite ends of the
muntin bar 22 are cut by a saw as described below to present a planar end E
that uniformly abuts
a generally flat surface of the spacer frame assembly 16. While both ends of
the bar 22 are
uniformly cut to define generally planar abutting ends, the two shorter
transverse muntin bars 24,
26 each have one flat end E for abutting a spacer frame and an inwardly facing
mitred end that
overlies the center section 23 of the bar 22 in the region of the slot 30.
Figure 3 shows a~length of stock mater-ialsS that is to be formed into a
muntin bar
according to the invention. One side of the stock material S may be coated or
otherwise treated
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to include a decorative color or pattern. The stock material S is in the form
of thin ribbon stock
material and may comprise, for example, aluminum or steel. According to the
invention, the
ribbon stock material S is fed lengthwise through a muntin bar production line
100 including a
series of forming stations and is formed into a muntin bar such as those
depicted in Figures 2A
and 2B.
A first forming station (described in more detail below) forms one of three
dif'-rerent notch
patterns P 1 & P3 at precise locations along the length of the stock material
S. The choice of the
particular notch pattern depends on the type of muntin bar being formed.
Downstream from the
first forming station, a second forming station bends the notched sheet
material into a tubular
1o muntin bar. Figure 4 schematically illustrates the preferred manner in
which the stock material S
is formed into a contour muntin bar. The stock material S is folded from its
flat configuration in a
series of steps to form a muntin bar having a desired contoured cross-
sectional configuration. The
finished configuration of the illustrated tubular muntin bar comprises a
tubular member closed
about its periphery. A third forming station severs the tubular muntin bar at
a desired
predetermined location. To form properly finished mitred ends on muntin bars
that engage the
sides of other muntin bars, the third forming station also finishes the mitred
end (or ends) of the
bar so that the bar can overlap the side portion of a transversely extending
bar such as the muntin
bar 22 in Figures 2A and 2B.
Figures SA and SB depict a muntin bar production line 100 constructed
according to a
preferred embodiment of the invention. The production line 100 comprises a
stock supply station
102 from which stock sheet material is fed to a first forming station 104. At
a second forming
station 110 downstream from the first station 104 the sheet is formed into an
elongated tubular
muntin bar. At a third forminig station 112 an endmost tubular muntin bar is
separated from the
muntin bar tube to form an individual muntin bar. Each severed end bar is
moved away from the
2~ severing station by an end station conveyor.
A scheduler/motion controller unit 120 (Figure 7) is preprogrammed to co-
ordinate and 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, and
other parameters involved
in production. Most preferably the controller unit 120 includes a programmable
controller having
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CA 02310993 2000-06-08
a central processing unit that presents a user interface to allow the forming
steps performed by the
production line 100 to be changed during set up of the line 100.
The production line 100 that operates under control of the controller unit 120
produces
sequences of muntin bars that make up a grid. The grid G' of Figure 6 is one
such grid. This grid
is made up of eleven different muntin bars having different lengths and
different end
configurations which are used in a particular window size. When a different
size window and
hence different length and width spacer frame is needed, the user need merely
enter dimensions of
the frame into the controller unit 120 and indicate the number of panes that
the grid needs to
define and the newly specified grid is produced by the production line. The
last muntin bar of the
previous grid G' and the first muntin bar of the newly specified grid can be
produced one after the
other without inconvenience of extended machine setup or production of scrap
produce between
jobs.
Units can be different from unit to unit in configuration, size, offset and
color. In
addition, some units will contain muntin bars having multiple colors and stock
sizes. Multiple
orders for all required units are inputted into the controller. The controller
schedules the order in
which the muntin bars will be made to maximize efficiency. The software in the
controller filters
the muntin bars required for each grid by a common stock inventory type. The
controller 120
makes all the muntin bars for a selected stock or inventory type for a
particular grid, groups them
and moves on to the next grid needing muntin bars made of the selected stock
or inventory type,
2o until all scheduled muntin bars of a particular inventory type are made.
The next roll of ribbon
stock or inventory type is loaded into the machine and all the scheduled
muntin bars for that stock
or inventory type are made and grouped. For example, if 1.5" stock with white
finish is loaded in
the machine, the controller will make and group the muntin bars for all
scheduled jrids that are
made from 1.5" stock and are white before routing orders for muntin bars made
from a different
stock or inventory type. These convenience features are not available during
muntin bar
fabrication processes used in the prior art.
The Stock Su olv Station 102
The stock supply station 102 comprises a support 106 for coiled ribbon stock
121 and a
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loop feed sensor 108. The ribbon stock S typically has a finished surface that
forms the exterior
of the muntin bar and thus should not be scratched, marred or otherwise
damaged during
production of the muntin bars. The 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 to a coil support unit and a stub axle assembly 123 which
supports the coiled
stock. The axle assembly 123 is provided with a coil clampinS reel structure
(not shown) at its
projecting end on which the coil is received. A drive motor and transmission
assembly (not
shown) drives the axle assembly 123 to feed stock from the support 102. The
clampinj reel
structure is adjustable to receive coils having different widths depending
upon the size of the
1o muntin bars to be produced by the production line 100.
The loop feed sensor 108 coacts with the controller unit 120 to control the
motor of
supply station 102 to prevent paying out excessive stock yet assuring a
sufficiently high feeding
rate through the production line 100. The loop sensor 108 comprises a stand
150 positioned
adjacent the stock support 106, a first arcuate stock guide 1 ~2 for receiving
the stock from the
support 106, and a loop signal processing unit 153. Stock fed to the sensor
108 from the support
102 passes over the guide 152, droops in a catenary loop 154 and passes over
a~second arcuate
stock guide 164 (which forms part of a first forming station, described below)
upon exiting the
loop sensor 108. The depth of the loop 154 is maintained between predetermined
levels by the
unit 153. The unit 153 includes an ultrasonic loop detector 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 sends a signal to the controller unit 120
which in turn
controllably activates the motor that drives the axle assembly 123.
The First Forming Station 104
The first forming station 104 is preferably in the form of a material removal
station that
receives stock from the loop sensor 108 and performs a precise punching
operation on the stock
as it is held in position. In the preferred embodiment, the forming station
104 comprises a
~3
supporting framework 160 fixed adjacent the loop sensor, and first and second
stock punching
units 162, 163 carried by the framework 160. The preferred forming station 104
can removes
CA 02310993 2000-06-08
material from the strip S to form one of the three notch patterns P 1 & P3 of
Figure 3. In figure 3,
the designation P2 is a notch pattern that produces a flat muntin bar end F
that abuts the spacer
frame, the designation P3 is a notch pattern that produces a >mitered end 1~1
meaning a muntin
bar end that fits over a side of a transverse muntin bar and is attached by
means of a joiner clip 28,
and the designation P1 is for a notch pattern that produces an elongated slot
30 to accommodate
a clip 28 at an appropriate position along the side of the muntin bar.
The framework 160 has an arcuate stock guide 164 that directs the stock from
the sensor
108 through a ribbon path of travel P extending through the stations of the
production line 100.
The first punching unit 162 (Figure 11) has a notching assembly 168 mounted
for up and down
movement and is driven by a first ram assembly 172. The second punching unit
163 has a
notching assembly 170 that is also mounted for up and down movement and is
driven by a second
ram assembly 173. The notching assembly 168 is positioned over a lower die, or
anvil, 175
disposed beneath the stock travel path P and includes first and second upper
punches, or
hammers, 176, 177 disposed above the travel path. The hammers 176, 177 have
sharpened edges
to punch through the stock. The stock passes through an opening 169 in the
anvil 175 as it enters
the punching unit 162. The controller 120 stops the stock feed when the
location for a notch is
properly located between the dies. The anvil clamps the strip material S.
The two hammers 176, 177 and the anvil 175 that backs these hammers are
mounted to a
2o slide 180 that is moved back and forth transverse to the direction of
movement of the stock S so
that the controller 120 can punch an appropriate one of the notch patterns. A
suitable drive such
as an air actuated cylinder coupled to a pressure source P1 moves the slide
and attached hammers
176, 177 to cause the appropriate hammer to be positioned relative to the
stock material S when
the ram 172 is actuated. The hammer 176 has two narrow punches that create the
pattern P2.
The hammer 177 forms the pattern P 1. The second notching assembly 170 has a
single die and
anvil pair 178, 179 that are brought together by actuation of the second ram
assembly 173 to
punch the pattern P3. _i
s
The ram assemblies 172, 173 are securely mounted atop the framework 160 and
connected to a source P 1 of high pressure operating air via suitable conduits
(not shown). The
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ram assemblies 172, 173 are operated from the controller 120 which outputs a
control signal to a
suitable conventional ram controlling valve arrangement (not shown) when the
stock has been
positioned appropriately for punching. The stock is fed to the station 104,
stopped at a location
which properly positions the stock relative to the punching units 162, 163 and
an appropriate one
of the two ram assemblies is operated under control of controller 120 to cause
the punching unit
to remove the desired portion of the stock. Upon completion of punching, stock
feed 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 an appropriate one of the two
punching units 162,
163 is actuated.
A servomotor 180 attached to the framework 160 feeds the strips to a second
loop sensor
182. The depth to which strip S droops in this sensor 182 is monitored by a
sensor and so long as
the strip is within a specified range the servomotor 180 is de-energized. As
the strip is fed
through the second forming station 110 the strip is taken up until its level
triggers the sensor
causing the control unit 120 to activate the motor 180.
The Second Forming Station 110
The second forming station 110 is preferably in the form of a rolling mill
that roll forms
the stocks received from the first forming station 104 into a tubular muntin
bar T. In the
preferred embodiment of the invention, the second forming station 110
comprises a support frame
2o structure 200 and sixteen sequentially mounted roll assemblies 202 & 217
(Figure 15) carried by
the frame structure 200. The roll assemblies each include top and bottom rolls
(the first assembly
of Figure 16A has rollers 202a, 202b for example) that are driven by a drive
transmission system
(Figures 17A and 17B) for simultaneously driving all sixteen roll assemblies.
The support frame structure 200 comprises a base 220 positioned in line with
the stock
path of travel P immediately adjacent the first forming station 104. A roll
supporting frame
assembly extends along opposite sides of the stock path of travel P with the
stock path of travel P
extending centrally therethrough. The roll supporting frame section supports
the roll assemblies
202 - 217.
Each roll assembly is supported by a lower support beam 240 and an upper
support beam
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244 that extend along substantially the entire length of the rolling mill
beneath roll assemblies 202
- 2I 7. A series of spaced apart vertical upwardly extending stanchions 242
are fixed to the beams
240 and 244, one pair of vertically aligned roll pairs are supported between
each successive pair
of the stanchions 242. Each pair of rolls extends between a respective pair of
stanchions 242 so
that the stanchions provide support against relative movement in the direction
of the 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 formed by an
assembly.
In the preferred embodiment of the invention, each roll assembly 202 - 217 is
formed by
pairs of vertically aligned upper and lower rolls that define a single "pass"
of the rolling mill.
Each roll assembly 202-217 comprises a bearing housing , upper and lower roll
shafts extending
through a bearing in the housing , and upper and lower stock forming rolls
respectively disposed
on the inwardly projecting ends of the shafts . One or more guide rolls are
provided adjacent the
forming rolls to ensure the ribbon stock is moved through the roll nips
without bending or
kinking. The bearing housings are captured between adjacent stanchions 242.
Drive pulleys or
sprockets for rotating the rolls are disposed on the opposite ends of shafts
and project laterally
outwardly from the support unit.
The upper support beam 244 carries a nut and screw force adjuster combination
245
associated with the upper roll of each roll assembly 202-217 for adjustably
changing the gap
between the two rolls of a roll assembly. The adjuster comprises a screw
threaded into the upper
roll bearing housing and lock nuts for locking the screw in adjusted
positions. The adjusting
screw is thus rotated to positively adjust the position of each upper roll
relative to its
corresponding lower roll, the lower support beam 240 fixedly supporting the
lower roll of each
roll assembly. The force adjusters enable the rolls in each pair to be moved
toward or away from
each other to increase or decrease the force with which the roll assemblies
engage the stock
passing between them.
A drive transmission system (Figure 17A) comprises a motor 223 fixed to the
base and is
preferably an electric servomotor energized by the controller unit 120. The
motor speed can be
continuously varied through a wide range of speeds without appreciable torque
variations. The
motor 223 is preferably disposed on its side with its output shaft extending
horizontally and
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laterally relative to the stock path of travel P and connected to a drive
sprocket 224. The drive
sprocket 224 is coupled to the roll assemblies 202-217 so that the roll
assemblies are positively
driven whenever the servomotor is operated. The sprocket 224 drives a sprocket
attached to the
bottom roller 217b of the last stage which drives a chain 227 reeved around a
pair of drive
sprockets connected to the top rollers 217a, 216a. A drive chain 228 couples
adjacent pairs of
top rolls 216a, ... 202a. The drive chain is reeved around the drive sprockets
of each top roll of
each of the roll assemblies 202-217. The bottom rolls 216b ... 202b are
interconnected by idler
sprockets 229. Accordingly, whenever the motor 223 is driven, the rolls of
each roll assembly are
positively driven in unison.
to The forming rolls of the roll assemblies 202-217 are configured to
progressively form the
ribbon stock from a flat sheet S into a tubular muntin bar T. Successive
stages of the rolling mill
bend the sheet S into a tubular bar T as seen in Figure 4. The first roll
assembly 202 is shown in
greater detail in Figure 16A. The rolls 202a, 202b bend the planar sheet S to
produce a center
plateau 232 bounded by two valleys 234, 236. The rolls 202a, 202b also produce
two outer
segments 238, 240 angled with respect to the two valleys 234, 236. At the
extreme edges of the
sheet S the rolls 202a, 202b form upwardly bent lip segments 239.
As the strip S passes through the next three subsequent stages (roll
assemblies 203, 204,
205), the outer lips 239 are further bent until after the stage defined by the
roll assembly 205 the
lips 239 form an angle'a' with respect to the outer segments 238, 240 as seen
in Figure 4. In the
2o completed tubular muntin bar T the two lips on opposite sides of the strip
are bent toward each
until they touch and form a seam 242. The tubular muntin bar T formed by the
station 110 has
notch patterns P1, P2, P3 punched at precisely located positions along the
length of the tubular
muntin bar.
The angle 'a' between the segments 23 8, 240 and the extreme end portion or
lip 239 stays
the same until the fifteenth stage where the lip 239 is again bent inward to
form the seam 242
along a line of engagement of the two lips 239. Figure 16B shows the seventh
stage (roll
assembly 208) illustrating that the rollers 208a, 208b do not engage and
therefore do not further
bend the lips 239 as the strip passes through the rollers 208a, 208b.
Experience with the roll
forming station indicates this process of delaying the last bending until the
next to last roll
14
CA 02310993 2000-06-08
assembly reduces the build up of stress within the tube T. This in turn tends
to reduce splitting
open of the seam and the muntin bar end where the bar is sever ed from the
tube T. The fifteenth
and sixteenth roll assemblies 216, 217 are the same shape. The second roll
assembly 217
straightens the completely bent tubular muntin bar prior to severing
individual muntin bars from
the strip.
Figure 16C shows the cross section 400 of a completed muntin bar. The cross
section 400
defines a perimeter that encloses an area having the general shape of a cross.
The cross-shaped
area defined by the perimeter of the formed muntin bar has tu~o relatively
narrow top and bottom
legs 402, 404 and two relatively wide side legs 406, 408. The ends 410, 412 of
the top and
to bottom legs are generally parallel to one another and the ends 414, 416 of
the two side legs are
generally parallel to each other. The length of the top and bottom legs 402,
404 is the same and
the length of the two side legs 406, 408 is the same. The width of each leg
tapers down along its
length, so that the angle formed by the side of one of the top or bottom legs
and the side of one of
the side legs is an obtuse angle. A seam is formed at the end of one of the
legs where two edges
of the material used to form the tube meet. In the exemplary embodiment the
seam of the muntin
bar is in the center of the top leg.
The Third Forming Station 112
The third forming station 112 is a muntin bar severing and finishing station
that severs an
2o endmost tubular contoured muntin bar as it exits the forming station 110
and delivers it to a convey
at the end station. In the case of a mitred end defined by the notch pattern
P3 the station 112 also
performs a finishing step to allow the mitred end to accurately overlap and
engage the elongated
muntin bar (22 in Figure 2A) with it mates. In the preferred embodiment, the
third forming station
112 is fixed to the end of the frame 200 that supports the roll assemblies. A
saw that performs a
severing step is attached to a vertical slide 306 attached to the framework
302. Up and down
movement of the slide 306 causes the saw to move in and out of the path of the
strip to sever an
endmost muntin bar from the elongated tube T of connected muntin bars formed
in the second
s
forming station 110.
Three optical sensors 308, 309, 310 (Figure 14) that are mounted to monitor
movement of
CA 02310993 2000-06-08
the tubular muntin bar T at the third forming station. Output from the sensors
allow the controller
120 to determine a type of notch pattern (P1, P2 or P3) that was formed in the
strip S prior to
bending of the strip into the tube T. Two sensors 308, 309 look across the
tube T and one sensor
310 senses the tube from above the path of tube movement.
Turning to the schematic depiction ofFigure 14, one sees that the notch
pattern P1 produces
two narrow slots 312 on opposite sides of the tube T that disrupt the surfaces
S 1, S3. Light from the
sensor 308 striking the slot 312, for example does not bounce off the surface
S 1 but instead passes
through the tube T to a sensor receiver (not shown) on an opposite side of the
tube T. The receiver
sends and appropriate signal to the controller 120.
to If the sensor 310 senses a notch along the surface S? it can either be a
side slot 30 to
accommodate a clip or it can be the notch for a mitred end. In either event, a
receiver beneath the
tube T will pick up a signal from the sensor transmitter. To distinguish
between a slot and a mitred
end, the output from the sensor 309 is used. When this slot 30 is sensed, the
computer 120 does not
activate the saw and the slot 30 is allowed to pass through a severing region
of the third forming
station.
During operation of the sensors 308-310, the controller 120 waits until a
signal is received
from either sensor 308 or sensor 310. Assume the sensor 310 is activated. If
the sensor 309 is not
also activated a slot 30 from the pattern P 1 has been sensed and wo cut is
performed. If a signal
sensor 310 is received and also from sensor 309 through a mitred end pattern
P3 has been sensed.
2o A signal from only sensor 308 means a cut only pattern P2 has been sensed.
When one of the two narrow registration slots 312 which define the position of
the flat end
F of the muntin bar are sensed, the controller 120 clamps the muntin bar tube
T in place and moves
the saw up from its home position through the region of the muntin bar strip T
to sever the endmost
muntin bar. A downstream clamp 314 includes first and second moveable clamp
members 316, 318
having clamping surfaces facing inwardly to clamp the muntin bar tube T
downstream of the severing
region. A second, upstream clamp 320 includes first and second moveable clamp
members (only one
is depicted in Figure 12) having clamping surfaces facing inwardly clamp the
muntin bar tube T
3
upstream of the severing region. Both clamps are actuated to clamp the tube T
prior to severing.
A mitred end notch pattern P3 (sensed by the sensors 309, 310) is interpreted
by the controller
16
CA 02310993 2000-06-08
120 as requiring first a severing of the strip S through a midpoint of the
semicircular notches 330,
332 and secondly a finishing of the two mitred bar ends. ,One of these mitred
ends is the upstream
end of the separated muntin bar and a second mitred end is the downstream end
of a sood to be
severed muntin bar still attached to the tube T. As in the case of a fiat end
F, when forming two
facing mitred ends M, the tube T is first clamped on either side of the
severing region and then the
saw is moved up from its home position to sever the endmost muntin bar.
To perform the finishing step, as the saw is retracted away from the severing
region, the still
clamped and now severed muntin bar is shifted an appropriate distance 'X' in
the direction of bar
movement. This brings the two oppositely facing severed ends of the tube a
distance D apart. To
1o accomplish this side shifting of the severed muntin bar the two downstream
clamp members 312, 314
are mounted for movement along the travel path of the tube T. After the
severing of an endmost
muntin bar, the clamp members are shifted downstream by a clamp drive 340 to
widen the gap
between the mitred ends Ml, M2. The controller 120 then causes an
appropriately configured router
bit 350 (Figure 10) rotating at a high rate of speed to pass between the two
mitred ends M1, M2.
By shaving o$'portions of specific regions 3~2, 353, 354 ofthe mitred ends M,
the completed muntin
bar will overlie the transverse muntin bar at the region of the clip. ~If the
finishing step is not
performed, the mitred end would only fit over but not properly seat against
the surfaces S2, B 1, B2
of the transverse muntin bar 22. The sequence of severing a clamped end of the
tube T, shifting a
severed bar downstream and moving a router bit 3~0 between the two mitred ends
Ml, M2 is
depicted in the sequence of Figures 9A - 9D. The perspective assembly view of
Figure 12 and the
exploded perspective view of Figure 13 more completely depict components of
the third forming
station 112. The saw is preferably mounted to the platform 306 so as to be
movable into cutting
engagement with the tubular muntin bar tube T upon receiving an appropriate
control signal from the
controller 120. As depicted in the drawings, a suitable actuator for moving
the saw includes the
combination of a servo motor 360 and a ball screw linear actuator 362 coupled
to the platform 306.
The linear actuator moves three inter-connected brackets 364, 366, 363. The
third of these brackets
368 supports the saw for up and down movement relative to the travel path of
the tube T. The
bracket 368 also supports a motor mount 370 which in turn supports a motor 372
having an output
shaft 3?4 and attached pulley 376. Reeved over the pulley 376 is a belt which
engages a second
17
CA 02310993 2000-06-08
pulley 378. The second pulley 378 is attached to a shaft 380 that extends
through a bearing housing
382. On an opposite side of the housing 382 the shaft 380 supports a circular
saw blade 383 for
rotation. The housing 382 is attached to the bracket 368 so that the motor
moves in unison with the
saw.
In its home position the router is spaced above the tube T. By raising the
saw, the controller
severs the muntin bar. By lowering the router bit 350 the controller fnishes
the mitred ends M of the
muntin bars. The router bit is supported by a shaft 384 that extends from a
high speed (23,000 rpm)
motor 386. The motor 386 is attached to a router mount 388 coupled to the
bracket 366 and also
moves up and down with the saw blade.
1o The severing and routing steps create a good deal of scrap material in the
region of the
clamps. A saw blade shroud 390 is attached to the bracket for up and down
movement with the saw
blade to impede debris from flying away from the blade region. A router bit
shroud 392 is attached
to the motor 386 and includes a cylindrical extension having a source of
suction (not shown) that
removes debris from the region of the router bit 350 as the mitred ends are
finished.
The End Station 113
The production tine has a conveyor C that carries the muntin bars away from
the stock path
of travel P. The illustrated conveyor -comprises a frame with posts 412 and
rails 414 supporting a
plurality of conveyor belts 416 that extend across the upper portion of the
conveyor frame, the belts
2o being reeved around sprockets or pulleys 418 rotatably mounted to the
frame. A motor 420 drives
a gearbox and drive belts to rotate a drive shaft 424, which in turn rotates
the sprockets to drive the
conveyor belts 416. The conveyor belts 416 preferably engage the individual
muntin bars and convey
the bars transversely away from the path of travel P.
The conveyor C moves muntin bars away from the path of travel of the muntin
bars in batches
or groupings. All the bars depicted in Figure 6, for example, are produced
serially and come off the
conveyor in a direction generally perpendicular to the direction of movement
as they are being
punched, cut, shaped etc.
The Controller Unit 120
18
CA 02310993 2000-06-08
In the preferred embodiment of the invention, the controller unit 120 (Figure
7) comprises
a personal computer having a display monitor 121, an operator accessible
keyboard 122, and a central
processing unit (CPU) which governs operation of the productioh line 100. The
CPU includes a
programmable microprocessor that executes a control program containing a
schedule of operations
to be perforTned to produce a batch of individual muntin bars suitable for
subsequent assembly into
a grid such as the grid G of Figure 2A or the grid G' of Figur° 6. The
microprocessor commands
control feeding the stock from supply station 102, and processing of the stock
at stations 104, 110,
112 and 114. These stations are coupled by a link or line of communication
between each of the
various stations and the controller 120. The control program thus dictates the
production 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 1, are to be
produced, the stock is fed
from supply station 102 and a signal is output from the loop feed sensor 108
to the controller unit
120. The controller unit 120 speeds up, slows or stops the supply station
motor to control the feed
rate of stock to the production line 100.
The stock is fed to the first forming station 104 with the controller 120
monitoring the feed
rate of stock and stopping the feed during activation of the two punching
units 162, 163. The stock
feed resumes and the notched stock is fed to the second forming station 110
where it passes through
the rolling mill and is formed into a tubular muntin bar T. -
The controller 120 controls the third forming station 112 to sever the tubular
muntin bar into
appropriately sized individual muntin bars, the sensors 308, 309, 310 transmit
data to the controller
120 regarding the flow of stock through the line as discussed above. The
sensors 308, 309, 310
transmit a signal that correctly indicates position of stock in the line even
if slippage occurs, due to
the encoder signal being generated by optical sensing of the tubular member.
Additionally, if desired,
the controller 120 may govern operation of the conveyor C in removing the
finished muntin bars from
the stock path of travel P, for example, by conveying the muntin bars to
another location (not shown)
where they are assembled into a grid for use in an insulating glass unit such
as that shown in Figure
1. The conveyor C is activated independently of the drive system for moving
the strip and tubular
bars to the severing station. This allows the controller 120 to maintain
movement of the bars that
make up a completed grid G and provide a spacing between completed grids. When
the last bar of
19
CA 02310993 2000-06-08
a particular stock type to a particular grid is completed, the controller 120
maintains movement of
that endmost bar away (in a transverse direction) from the severing and
finishing station while
suspending movement ofthe first muntin bar of the.ne:ct grid. ~ spacing
between the multiple muntin
bars for a particular grid results. This spacing allows the operator to
identify those bars that make
up a completed grid so that they can be grasped by the operator and either
assembled immediately
into a grid or placed aside for assembly at a separate location.
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 scope of the invention as defined in
the claims.
s
