Note: Descriptions are shown in the official language in which they were submitted.
1
This is a division of Patent Application Serial
No. 456,851 filed July 3, 1984.
The g>resent invention relates to a method for
producing a fibrous material product from a mat of glass
fibers arrana~ed in laminations extending at least
substantially parallel to opposite major surfaces of the
mat.
It is well known to those skilled in the art that
a mat of glas:~ fibers produced by attenuating the glass
fibers from spinners in a forming section and depositing
the thus-attenuated glass fibers onto a conveyor exhibits
a laminar structure, in that the thus-deposited glass
fibers tend to assume an orientation in the mat in which
the glass fibers form layers or laminations extending
generally parallel to the opposite major surfaces of the
mat.
It has for a long time been recognized that a
glass fiber m<~t fo~.-med in this way has a considerably
greater compression strength parallel to its laminations,
i.e. parallel to the majority of the glass fibers in the
mat, than in a direction at right angles to the
laminations.
For this reason, glass fiber mats have in the past
been pleated to rearranged the glass fiber laminations so
that the latter come to extend across the thickness of the
mat. Such pleating is effected by passing a glass fiber
mat between successive pairs of upper and lower conveyors
driven at successively slower speeds, so that the mat is
folded in a corrugated shape, the corrugations being
compressed. Thus, a glass fiber mat pleated in this manner
exhibits, in side view, glass fiber laminations which have
been bent into a corrugated shape and pressed together.
United States Patent 2,409,066, issued October 8, 1946 to
Edward R. Powe:ll et al and United States Patent 2,500,690
issued March 14, 1950 to George M. Lannan describe prior
art pleating processes.
i3~4~~z
2
However, it is a disadvantage of a pleated glass
fiber mat that such a mat exhibits an undesirably low bending
strength, since the mat tends to break apart between the
adjacent pleat.>-or corrugations when subjected to a bending
moment.
It has also been proposed, for example in
United States Patent 3,012,923, issued December 12, 1961 to
G. Slayter and Canadian Patent 909,130, issued September 5,
1972 to Gullfiber AB, to cut a laminar glass fiber mat into
sections, which are then rearranged and adhered together so
that the lamination, extend across the thickness of the
resulting product.
The present inventors have now found that a mat of
glass fibers containing glass fiber laminations can be
processed, without pleating the mat and without cutting the
mat into sections, so as to deform and rearrange the
laminations to provide a product in which at least the major
portion of the :laminations extend across the thickness of the
mat instead of parallel to the opposite major surfaces of the
mat.
More particularly, the present invention provides a
method of producing a non-pleated reoriented glass fiber
fibrous material having improved bending strength comprising
the steps of: advancing a mat of glass fibers arranged in
laminations extending at least substantially parallel to
opposite major surfaces of said mat; impregnating said mat
with a heat-curable bonding substance; passing said mat along
a gap extending between successive pairs of driven elongate
conveyor means which engage the opposite major surfaces of
said mat to control the advance of said mat along said gap;
driving said pairs of' conveyor means at progressively slower
speeds along said gap while deforming said laminations of said
mat in at least two separate stages into a non-pleated
reorientation :in which at least a major portion of said
laminations extend across the thickness of said mat; and
subsequently heating said mat to cure said bonding substance.
~34~~5~
- 2a -
A:nother aspect of the invention provides a method
of producing a fibrous material product comprising the steps
of: forming a mat of glass fibers arranged in laminations
extending air least substantially parallel to opposite major
surfaces of the mat; impregnating said mat with a heat-
curable binder; passing said advancing mat along a gap
extending between successive pair of driven elongate
conveyor means which engage opposite major surfaces of the
mat to control the advance of the mat along said gap;
driving said pair of conveyor means at progressively slower
speeds at positions spaced apart along said mat so that the
laminations of said mat are deformed, in at least two
successive stages, from their initial orientation into a
reorientation in which at least a major portion of said
laminations extend across the thickness of the mat; and
subsequentl!T heating the mat to cure said binder.
A further aspect of the invention provides a
method for t:he continuous formation of felts from fibers of
a glass mats:rial <:oated with a binder composition which are
distributed onto a receiving member retaining the fibers,
comprising i~he steps of progressively passing a fiber felt
between at least three pairs of conveyors having speeds
controlled i=o allow at least two longitudinal compressions
of the fiber felt, the passage from a first pair to a second
pair of conveyors effecting a first longitudinal
compression,, and the passage from the second pair to a third
pair of conveyors effecting a second longitudinal
compression of the felt.
Its has been found, in practice, that due to the
lengths of t:he glass fibers, the deformation of the glass
3
fiber laminations cannot be effected satisfactorily in a
single stage, since excessive pleating of the glass fiber
mat occurs, but that such excessive pleating can be
avoided by initiating the deformation of the laminations
at one stage and then completing the deformation in one or
more subsequeni~ stages.
Preferably, endless belts are used as the
conveyors, the endless belts being arranged in pairs with
each successive pair being driven at a speed slower than
the preceding pair. Also, each successive pair of the
conveyors may be spaced apart by a greater or lesser
distance than the preceding pair, in order to allow
control of the thickness of the mat as it passes from each
pair of conveyors to the next pair.
To counteract pleating of the mat, suitable
guide means, for example guide rollers or stationary guide
members, are preferably positioned between successive ones
of the lower and in some instances the upper endless belt
conveyors for contacting and guiding the major surfaces of
the mat as t:he mat passes between the successive
conveyors.
As the laminar glass fiber mat passes between
the conveyors, the conveyors engage and grip the opposite
major surfaces of the glass fiber mat and, due to the
progressively slower speeds of the conveyors, the
laminations within the thickness of the glass fiber mat
are forced forwardly, relative to the opposite major
surfaces of they mat, and thus bend and "bunch-up", so that
these laminations no longer extend parallel to the
opposite major surfaces of the glass fiber mat but form a
knit of reoriented laminations between opposite major
surfaces thereof.
The invention will be more readily understood
from the following description of preferred embodiments
thereof given , by way of example, with reference to the
accompanying drawings, in which:-
Figure 1 shows a diagrammatic side view of a
4
pro-production lines embodying the present invention for
processing a laminar glass fiber mat;
Figure 2 shows a broken-away view in side
elevation of a pair of the conveyor belts of Figure 1 with
a modified guide member therebetween;
Figure 3 shows a broken-away view in side
elevation of two successive pairs of conveyors and
illustrates tike def-_ormation of the fiber laminations as
the glass fiber mat passes from one pair of the conveyors
to the succeeding pair. of conveyors;
Figure 4 shows a more detailed plan view of a
production linE~ for ;processing a laminar glass fiber mat;
Figure 5 shows a more detailed side elevational
view of the production line of Figure 4;
Figure 6 shows a more detailed plan view of a
conveyor assembly for supporting an upper one of said
pairs of conve5ror belts;
Figure 7 is a side elevational view of the
conveyor assembly of Figure 6;
Figure 8 is a cross-sectional view of a track
sub-assembly for guiding the movement of the conveyor
belts supported by t:he conveyor assembly of Figures 6 and
7:
Figure 9 is a more detailed plan view of an
upper support frame for supporting the conveyor assembly
of Figure 6;
Figure 10 is a side elevational view of the
support frame of Figure 9;
Figure 11 is a partially sectional, elevational
view of a lift screw sub-assembly provided on the support
frame of FigurE~ 9;
Figm_-a 12 is a perspective, schematical view of
the drive assembly for the production line shown in Figure
4;
Figure 13 shows a broken-away view in side
elevation of a pair of conveyors and illustrates another
type of deformation of the fiber laminations as the glass
fiber mat passes between the pair of conveyors;
-- _...
Figure 14 shows an expanded view of an endless
conveyor of a sorts suitable for use in processing a
laminar glass fiber mat to avoid the deformations
illustrated in Figure 13;
5 Figure 15 shows a side view of a modified mat
processing conveyor arrangement in which the endless belts
of Figures 1 to 3 are replaced by an arrangement of
rollers;
Figure lEi shows a plan view of the roller
arrangement of Figure 15; and
Figure 17 is a cross-sectional view of a section
of crimped glass fiber mat.
Referring firstly to Figure 1, the production
line illustrated therein has an infeed conveyor indicated
generally by reference numeral 10 for receiving a laminar
glass f fiber mat from a forming section, which is of the
type well known in the art and which, therefore, is not
illustrated in the present drawings.
From the forming conveyor, the glass fiber mat,
indicated by reference numeral 12, is advanced between
three successive pairs of endless conveyor belts,
indicated by reference numerals 14a, 14b, 15a, 15b and
16a, 16b, which are driven by a suitable motor and drive
transmission (not chown) and which engage and grip the
opposite major surfaces of the glass fiber mat 12.
As can be seen from Figure 1, the conveyor belts
15a and 15b are spaced apart from one another by a
distance which is greater than the spacing of the conveyor
belts 14a and :14b from one another, and the conveyor belts
16a and 16b, in turn, are spaced apart from one another by
a distance which is greater than the spacing between the
conveyor belts 15a .and 15b. Thus, the pairs of conveyor
belts are spaced apart by progressively increasing
distances in succession along the path of advance of the
glass fiber belt 12.
This arrangement of spacings is particularly
suited to the crimping of relatively thick mat and is
therefore described for purposes of illustration only. As
6
will be discus~~ed more fully below, different arrangements
of spacings arcs contemplated, including a smaller spacing
between conveyor belts 16a and 16b relative to belts 15a
and 15b when crimping relatively thin product.
Beyond the conveyor belts 16a and 16b, a further
pair of spaced apart conveyor belts 17a and 17b, are
provided for feeding the glass fiber mat 12 through means
for heating such as a curing oven indicated generally by
reference numeral 20.
The spacing between conveyor belts 17a and 17b
will vary depending upon product thickness and will
therefore typically approximate the spacing between
conveyor belts 16a a:nd 16b.
Beyond the conveyor belts 17a and 17b, a
conveyor 22 is provided for conveying the processed and
cured glass fiber mat to a cutting section (not shown), at
which the main is cut into sections for wrapping and
packaging at a suitable packaging station. The cutting
section and the packing station are of conventional
construction and operation and, therefore, not illustrated
herein.
In operation of this apparatus, the conveyor
belts 14a and 14b are driven at the same speed as the
conveyor 10.
The conveyor belts 15a and 15b are driven at a
speed slower than the conveyor belts 14a and 14b, and the
conveyor belts 16a and 16b, in turn, are driven at a speed
which is slowcsr than that of the conveyor belts 15a and
15b. The conveyor belts 16a, 16b, 17a, 17b and 22 are
driven at the came seed.
As t:he glass fiber mat 12 passes from the
conveyor belts 14a and 14b to the conveyor belts 15a and
15b, and due to the slower speed of the latter, the glass
fiber mat, across the thickness thereof between opposite
surface layers of the mat, is bunched-up due to the speed
differential between the conveyor belts 15a, 15b, on one
hand, and the conveyor belts 14a, 14b, on the other hand.
Consequently, the laminations of glass fiber in the glass
,.-
7
fiber mat 12, which as mentioned above are initially
parallel to the oppo:~ite major surfaces of the glass fiber
mat 12, are bunched-up more or less vertically and, thus,
a major portion of these laminations are deformed from
their. initial, parallel, generally planar orientation to a
reorientation i.n which they are bent so as to be inclined
from the longitudinal horizontal center plane of the glass
fiber mat 12.
Due to the relatively long lengths of glass
fibers, it is Eound, in practice, that it is not feasible
to effect the comp:Lete deformation and reorientation of
the glass fiber laminations in one stage at the transition
between the conveyors 14a and 14b, on one hand, and the
conveyors 1-'ia and 15b, on the other hand, since
excessively :rapid deformation of these glass fiber
laminations has a tendency to produce pleating of the
glass fiber mat: 12 .
The refore, the deformation of the glass fiber
laminations is completed in a subsequent, second stage, at
the transition between the conveyor belts 15a and 15b, on
the one hand, and the conveyor belts 16a and 16b, on the
other hand.
It has been found that, using a mat such as the
mat 12 which comprises laminations formed from glass
fibers, which are relatively long fibers, the deformation
and reorientation of a major portion of the laminations
should be effected in at least two separate successive
stages. However, it is to be understood that the
invention is not restricted to a method or apparatus in
which the glass fiber lamination deformation is effected
in only two such stages but that this deformation may be
carried out in three or more stages, depending upon the
initial and final thicknesses of the glass fiber mat.
For example, it has been found that, starting
with a glass fiber mat 12 having a thickness of one inch,
the thickness of the mat is preferably increased to
approximately two inches at the first stage, and is
subsequently increased to three inches at the third stage.
,...
8
It will be understood, however, that these figures are
given by way of example only, and that the thicknesses of
the glass fiber mat before and after each stage in the
deformation of the glass fiber laminations may vary
considerably, depending upon the initial thickness of the
glass fiber mat and the relative speeds of the conveyors
employed to deform the laminations of the glass fiber mat.
It has been determined empirically that a board
like product of good commercial quality is obtained when
the crimping ratio between conveyor belts 14a and 14b, on
the one hand and conveyor belts 16a and 16b on the other
hand, falls within the range from 3.0:1 to 4.0:1 and is
preferably 3.5:.1. By crimping ratio, what is meant is the
ratio of the number of incoming linear feet of laminar
glass fiber mat to the number of outgoing linear feet of
crimped product. Thus, for an overall crimping ratio of
3.5:1, one linear foot of crimped product will result from
the input of 3.5 linear feet of undeformed laminar glass
fiber mat.
In one embodiment constructed by the applicant
to be described in greater detail below, the crimping
ratio between conveyor belts 14a and 14b, on the one hand,
and conveyor b.=_lts 15a and 15b on the other hand is fixed
at 1.5:1. The relative speed of conveyor belts 15a and
15b, on the one hand, and conveyor belts 16a and 16b, on
the other hand, is then adjusted to produce a crimping
ratio therebetween of 2.33:1 resulting in an overall
crimping ratio of 3.5:1.
As will be appreciated, the difference between
the relative speeds, of the successive pairs of conveyor
belts closely approximates the crimping ratio
therebetween. Thus, for a crimping ratio of 1.5:1,
conveyor belts 14a and 14b travel at substantially 1 1/2
times the speed of conveyor belts 15a and 15b.
Although an overall crimping ratio of 3.5:1
appears optimal, ratios may be as high as 6.0:1 or as low
as 1.1:1 for more flexible products depending upon the
initial and final values of glass fiber mat thickness, the
~34p~5~
9
amount of crimping actually required and product
constraints.
The conveyor belts 14a-16b are made long enough
to grip the glass fiber mat sufficiently to ensure that
the laminations are deformed in the above-described
manner.
In order to ensure that only a small gap exists
between successive conveyor belts, e.g., between the
conveyor belts 14a and 15a and between the conveyor belts
14b and 15b, a.nd thus to provide improved control of the
deformation of the laminations and to avoid pleating of
the glass fiber mat at the gaps between successive
conveyor belt's, ro:Llers 24 on which the conveyor belts
14a-16b are provided should be of the smallest possible
diameter.
In addition, rotatable guide rollers 26 are
provided in thE~ gaps between the successive conveyor belts
for contacting and guiding the opposite major surfaces of
the glass fibE~r mat as the glass fiber mat passes these
gaps.
From the conveyor belts 16a and 16b, the mat is
guided by skid plates 28 or perhaps other means such as
rollers between the conveyor belts 17a and 17b, which pass
the mat throu<~h the curing oven 20, at which a suitable
binder, initially impregnated into the glass fiber mat 12
by spraying from spray heads 30 located above the conveyor
10, is heated and cured to bind the glass fibers together
in a manner we:Ll known to those skilled in the art.
Figure 2 shows a stationary guide 32 inserted
into the gap between successive conveyor belts, e.g.
conveyor belts 14a and 15a, for engaging and guiding the
lower major surface of the glass fiber mat, in place of
the corresponding freely rotatable roller 26 of Figure 1,
and it will be appreciated that each of the rollers 26 in
Figure 1 may bc~ replaced by a stationary guide such as the
stationary guide 32 of Figure 2.
Figure 3 illustrates the deformation of the
laminations of the glass fiber mat at the first stage,
"~--
~~40'~5~
i , a . between the conveyor belts 14a and 14b and the
conveyor belts 15a and 15b. As can be seen from Figure 3,
as the glass fiber mat approaches this first deformation
stage, the glass fiber laminations, indicated by reference
5 numeral 34, are initially generally planar, horizontal
laminations, parallel to the upper and lower major
surfaces of the glass fiber mat 12.
As the mat approaches and passes through the gap
between two pairs of conveyor belts and travels along the
10 gap between the conveyor belts 15a and 15b, these
laminations become increasingly deformed and are
reoriented into a pattern of crimps, as indicated by
reference numeral 36, wherein at least a major portion of
the laminations extend across the thickness of the mat.
Figures 4 and 5 are more detailed elevational
and plan views of a production line as constructed by the
applicant for crimping laminar glass fiber mats. Where
appropriate, hike reference numerals used in the preceding
figures have been used to identify like elements.
The production line as shown consists of an
infeed ramp conveyor 10 for delivering glass fiber mat
from the forming section (not shown) to the production
line consisting of t:he three successive pairs of conveyor
means such as belt conveyors 14a, 14b, 15a, 15b, 16a and
16b. The conveyor belts themselves which will be more
fully described below with reference to Figure 14 may be
generally seen in Figure 14 to comprise a plurality of
transversely extending, closely spaced metal slats or
flight bars 100 of rectangular cross-sectional
configuration provided between endless drive chains 101.
Each of the upper conveyor belts 14b, 15b and
16b is supported for rotation about conveyor assemblies,
also simply called conveyors 214b, 215b and 216b
respectively. In the embodiment as shown, each upper
conveyor includes in place of rollers 24 shafts 123 having
sprockets 124 provided adjacent opposite ends thereof.
Sprockets 124 engage drive chains 101 to rotate the
conveyor belts.
11
The construction of each of the upper conveyors
is quite similar and the construction of upper conveyor
214b only will therefore be described in greater detail.
With reference to Figure 6 and 7, conveyor 214b
consists of a framework including frame members 218 and
219. Frame member, 219 will sometimes be referred to
simply as frames and in the embodiment shown may be in the
form of lengths of channel-shaped beams. Welded or
otherwise aff;Lxed onto the outer surface of each frame
member 218 towards the outer ends thereof are pillow-block
mounts 220. Each pillow-block mount supports a pillow-
block 221 into which is rotatably received a respective
end of shaft 123. The shaft 123 shown to the right in
Figure 6 is actually the drive shaft for this conveyor and
includes a drive sprocket 125 (Figure 7) at one end. The
shaf t shown to the lef t in the drawing is an idler shaf t
and of course both shafts include sprockets 124 thereon to
engage drive chains :101 to rotate the conveyor belt.
The drive and idler shafts may each include a
roller 128 at a midpoint along their respective lengths to
lend additional support to the conveyor belt.
Intermediate aupport for shafts 123 themselves may be
provided by means of bushed plates or brackets 127.
The conveyor is provided with suitable means for
adjusting and maintaining the tension in conveyor belt
14b. These means may include a tensioner indicated
generally at 135. Tensioners of this sort are well known
in the art and will. not therefore be described in great
detail although the' tensioner will be generally seen to
include a take-up shaft 138 having sprockets 124 provided
at the ends thereof, take-up mounts 139 which support the
ends of the take-up shaft for. vertical movement and
rotatable jack screws 140 for adjusting the elevation of
the take-up shaft to maintain proper tension in conveyor
belt 14b.
A track a:>sembly to guide the movements and to
prevent undue flopping of conveyor belt 14b as it passes
....
12
beneath the underside of conveyor 214b is suspended from
the undersides of frame elements 219.
With reference to Figures 7 and 8, the track
assembly 141 consists of upper and lower track elements
142 and 143 uniformly spaced from one another except at
their ends which diverge somewhat by means of an outward
thinning of each element. The lower track 143 in
particular is supported by two or more L-shaped track
supports 144 attaclhed to frame elements 219 such as by
means of machine screws 145 or the like. With particular
reference to Figure 8, lower track element 143 is attached
to the track :supports 144 by means of threaded fasteners
146 and the upper track element 142 is attached to the
lower flanges of the outer frame elements 219 by means of
a threaded fastener 147, a lock washer 148 and a bevelled
washer 149.
The gap 1~i0 between the upper and lower tracks
is sized to closely accommodate drive chain 101 to
maintain a generally planar motion by constraints on its
upward and downward clearances.
To <:ontrol the gaps between the pairs of
conveyor belts, each of conveyors 214b, 215b and 216b is
vertically adjustable relative to lower belts 14a, 15a and
16a. Upper conveyor 214b is mounted for up and down
movement on an upper support frame 114b and upper
conveyors 215b and 216b are similarly mounted for up and
down movement on upper support frames 115b and 116b,
respectively. As t:he construction of each of the upper
support frames is substantially identical, it will once
again be sufficient to describe upper support frame 114b
only and it will be understood that this description will
apply to the two other upper support frames as well.
With reference to Figures 9 and 10, upper
support frame 114b consists of an essentially rectangular
framework of Elements including uprights 118, horizontal
frame members 105 and end members 106 and 107. As can be
seen most clearly from the view of Figure 5, upper support
frame 114b rests ai~op and is connected to corresponding
.-,.
13
lower support frame :114a by means of threaded fasteners or
the like.
A number of different means of moving the upper
conveyors in an up and down fashion will occur to those
skilled in the art but in the embodiment shown, an air
motor 160 is used to drive screw lift assemblies 165
provided at each o:f the upper corners of upper support
frame 114b. P,s will be described below, each screw lift
assembly includes a, threaded lift screw which engages a
respective corner of conveyor 214b to raise and lower the
conveyor as required.
As wall be seen most clearly from Figures 9 and
10, air motor 160 is attached to and supported by a gear
box 161 bolted to end member 106 for rotating a drive
shaft 162 extending upwardly from the gear box and which
has a drive sprocket 163 provided at its upper end as
shown. A first take-up sprocket 166 supported by a take-
up support mount l6Eia is located on the same side of end
member 106 as gear box 161 and a second take-up sprocket
167 supported by a econd take-up sprocket mount 167a is
located on the other side of end member 106 to be opposite
gear box 161. At least one of take-up sprockets 166 or
167 is adjustable in the longitudinal direction of end
member 106 for adjusting the tension in a lift screw drive
chain 102.
The acrew lift assemblies will now be described
with reference to Figure 11 which is a view looking in the
direction of arrow F3 shown in Figure 9. Each screw lift
assembly is of the same construction and the following
description wil_1 be understood to apply to each.
Generally, an L-shaped corner bracket 169 is
bolted or otherwise affixed to the corner defined by frame
element 105 and end member 106. The bracket includes a
bushed flange 7_70 through which one end of a threaded lift
screw 164 is journal.led to extend upwardly for connection
to a toothed sprocket 171. A grease nipple 170g is
provided for l~ibricating this joint. The lower end of the
lift screw 164 is rE~ceived into a bearing cup 173 and is
-. ~~4D7~,2
14
secured therein by means of a pin 174. An L-shaped bottom
bracket 175 is bolted to upright frame member 118 to
support the bearing cup.
Lift screw drive chain 102 encircles each of the
drive and idler sprockets as best seen in Figure 9 so that
each lift screw is rotated simultaneously and at the same
speed to avoid differential adjustments to the elevations
of the corners of conveyor 214b.
To effect. the raising and lowering of the
conveyor, the lift screws pass through correspondingly
threaded slug nuts 121 (see also Figure 6) provided at the
outer ends of conveyor frame members 218. The slug nuts
are nonrotatably fixed in position and are supported in
part by gussets 121a so that rotation of the lift screws
is translated into up and down movements of the conveyor
depending upon the direction in which the lift screws are
turned. Cam rollers 119 provided adjacent each slug nut
are positioned to engage the inner surfaces of upright
frame members 118 anal serve to stabilize the conveyor and
to guide its tip and down movements. Each cam roller is
journalled into a cam roller bracket 119b bolted to
conveyor frame members 219 preferably in a manner
permitting of some lateral adjustments to the positioning
of the cam rol7Ler relative to upright 118.
Lower conveyor belts 14a, 15a and 16a are
supported by lower support frames 114a, 115a and 116a
respectively.. Each of these lower support frames
generally comprises a rectangular framework of structural
members as shown and are essentially similar to one
another. As with the upper support frames, each lower
support frame includes at the upper opposite ends thereof
pillow block mounts 220 to which are mounted pillow blocks
221. Shafts 123 including toothed drive sprockets 124
adjacent the ends thereof are journalled into the pillow
blocks and as with the upper conveyor assemblies, the
toothed sproclkets 124 engage drive chains 101 to rotate
the conveyor belts.
~~4fl7~2
For belt tensioning purposes, lower frame 115a
includes a take-up shaft 109 supported for vertical
adjustments by take--up mount 108 and an idler shaft 110.
Similarly, lower support frame 114a includes a take-up
5 shaft 112 supported for vertical adjustments by take-up
mounts 111 and an idler shaft 113.
The take-up mechanism for lower support frame
116a is modified somewhat relative to the others in view
of the fact that the' length of lower conveyor belt 16a is
10 required to be variable. As mentioned above, a further
pair of conveyor belts 17a and 17b are provided beyond
conveyor belt 16a for feeding the glass fiber mat 12
through curing ov en 20. The temperature in the curing
oven is sufficiently elevated to result in significant
15 thermal expansion in the lengths of belts 17a and 17b by
as much as 12 inches., and the left-most shaft 123 as seen
in Figure 5 must therefore be free to float back and forth
to accommodate this expansion. Accordingly, whereas shaft
123 shown to the right on lower support frame 116a is
secured in the usual manner by means of pillow block
mounts 220 anc3 pillow blocks 221, the ends of shaft 123
shown to the lcsft on lower support frame 116a are received
into bearings slidat~ly supported by tracks (not shown) to
allow some freedom for back and forth movement of the
shaft. The ends of the shaft supporting the adjacent end
of belt 17a ar~~ similarly supported in the same tracks and
are connected to the' ends of left-most shaft 123 by means
of spacers (also not. shown), to maintain constant spacing
between belt: 16a and 17a. The resulting change of
distance between each of shafts 123 of lower support frame
116a due to the push/pull of thermal expansion is
accommodated by means of a take-up mechanism including two
idler shafts 131 and 132 (as will be described below,
shaft 132 is actually a drive shaft for conveyor belt 16a)
journalled into bearings mounted onto side plates 135 and
a take-up shaft 133. Take-up shaft 133 is journalled into
the ends of arms 1.79 which are pivotable about pivot
points 181. Take-up shaft 133 is weight-loaded to
16
maintain tension in drive chain 101 as left-most shaft 123
is moved to the right due to thermal expansion of belt
17a.
In the embodiment shown, the gaps between
respective pairs of upper and lower conveyor belts may be
adjusted within. the range of 1 inch to 24 inches. Gaps of
less than 1 inch are possible for thinner products.
Lower' conveyor belts 15a and 16a are mounted in
horizontal alignment with one another. Lower conveyor
belt 14a is supported by lower support frame 114a to be
horizontally a_Ligned with lower conveyor belt 15a but is
additionally pivotable about its associated shaft 123
closest to infeed conveyor 10. The pivoting movements of
lower conveyor belt: 14a are controlled by a hydraulic
piston and cylinder assembly 130.
Typically, the glass fiber mat delivered from
the forming station at the commencement of a run is not of
suitable qualii~y and is usually discarded. To this end,
lower conveyor belt :14a is pivoted in the counterclockwise
direction by piston and cylinder assembly 130 at the
commencement oi= the run whereupon the glass mat leader is
dumped beneath lower conveyor belt 15a. When pivoted like
this, conveyor 14a is run at double speed when down to
tear pieces from t:he mat on conveyor 10. When steady
state conditions are reached, conveyor belt 14a is pivoted
upwards to its horizontal operating position and its speed
is reduced to normal.
The successive pairs of conveyor belts are
arranged on their respective frames to minimize the
spacing therebetween which in the embodiment constructed
by the applicant is in the 1 inch range. It is also
important to choose sprockets 124 of the minimum possible
diameter to further minimize the size of the gaps between
successive belts. Sprocket sizes may vary in the 6 inch
to 10 inch range depending on conveyor belt sizing
requirements w:Lth 8 inches being preferred.
Rotatable guide rollers 26 are provided in the
spaces between lower successive conveyor belts for guiding
17
the lower major surface of the glass fiber mat over and
past the spacings. Similar guide rollers are not provided
in the spacings between successive ones of the upper
conveyor belta however in view of the typically unequal
vertical elevations of the upper conveyors when crimping
is occurring, and also as it has been found that the guide
rollers over a period of time become tacky due to
accretion of the bonding agent applied to the glass fibers
and develop a tendency to lift the mat up into the
spacing. This can develop to the point where the
conveyors became physically jammed and stall the drive
mechanism.
In the embodiment constructed by the applicant,
guide rollers 26 are driven at the same rotational speed
as the successive conveyor belt.
Conveyor belts 14a and 14b and 15a and 15b are
driven by thE~ same prime mover used to drive infeed
conveyor 10. With reference to Figures 4 and 5, a first
prime mover 1!~0 such as an electric motor drives infeed
conveyor 10 via a suitable gear reducer 151, a jack shaft
152 and interconnecting drive chain 153.
With particular reference to Figure 4, jack
shaft 152 includes a take-off sprocket 155 which connects
with a speed-u:p clutch 158 by means of chain 156. Speed-
up clutch 158 is engaged to rotate conveyor belt 14a at
double speed when the latter is in its downwardly pivoted
position. Speed-up clutch 158 rotates a drive shaft 170
on lower support frame 114b by means of a drive chain 157,
and as will be described below, drive shaft 170 is
connected to shafts 123 of support frames 114a and 114b to
rotate conveyor belts 14a and 14b at the same speed as
infeed conveyor 10.
Connected to speed-up clutch 158 by means of a
chain 169 is a. slow down clutch 159 which drives a drive
shaft 170 for conveyor belts 15a and 15b via a drive chain
174. As will become increasingly clear, the drive
mechanism for each pair of conveyor belts is somewhat
similar and like reference numerals have therefore been
18
used to denote like elements on the frames supporting the
belts .
Slow down clutch is continuously engaged to
rotate conveyor belts 15a and 15b at approximately two-
s thirds the speed of conveyor belts 14a and 14b to produce
a crimping ratio of 1.5:1 therebetween.
At this point, it will be convenient to refer to
Figure 12 which schematically shows the drive mechanism
for the present assembly line and wherein unnecessary
elements have been deleted for greater clarity.
As will be~ seen, drive shaft 170 on lower frame
114a includes at its end a toothed sprocket 176 connected
to speed-up clutch 158 by means of chain 157. A second
sprocket 172 on shaft 170 is aligned with a sprocket 173
provided at the end of drive shaft 123 of lower support
frame 114a to drive conveyor belt 14a by means of a roller
chain 175. The rotation of upper conveyor belt 14b is
accomplished b:~ means of a third sprocket 177 provided on
shaft 170 to align with a roller sprocket 178 journalled
into pillow blocks 1.78p supported on uprfight 118 of upper
support frame 114b. The mounting of roller sprocket 178
is best seen in the views of Figures 9 and 10. A roller
chain 180 interconnects sprockets 177 and 178 to form a
continuous running :Loop which engages the drive sprocket
125 provided at the end of drive shaft 123 of upper
conveyor 214b. A pair of idler sprockets 186 connected to
upper conveyor 214b bias roller chain 180 against drive
sprocket 125. Idler sprockets 186 are mounted onto an
idler plate 190 most clearly illustrated in the views of
Figures 6 and '7.
With reference to these figures, the idler plate
is bolted or otherwise affixed to pillow block mount 220
adjacent drive sprocket 125. The idler plate is apertured
at opposite ends for insertion of idler shafts 191 which
support idler sprockets 186. An elongated semi-circular
recess 192 is formed into the idler plate between the two
idler shafts 191 to provide clearance around the end of
shaft 123. A:~ will be obvious, idler plate 190 and the
~,.," °
.~34~75~
19
idler sprockets connected to it move up and down with
upper conveyor 214b.
As mentioned, the drive for conveyor belts 15a
and 15b is sut~stantially the same as that just described
for conveyor belts 14a and 14b and need not therefore be
further described other than with respect to a further
sprocket 188 provided at the end of associated drive shaft
170 for rotating roller 26. Roller 26 includes at its
adjacent end a sprocket 189 connected to sprocket 188 on
shaft 170 by means of a roller chain 187. The sprockets
188 and 189 are sized so that roller 26 is driven at the
same speed as 7_ower conveyor belt 15a.
Conveyor belts 16a and 16b are provided with
their own second prime mover 220 so that their rotational
speeds may be independently varied. Prime mover 220
includes motor 221 and speed reducer 222 connected via
drive chain 223 to .a drive sprocket 224 mounted on drive
shaft 170. Thereafter, the remainder of the drive
mechanism is much true same as that already described with
respect to conveyor belts 14a and 14b and 15a and 15b with
the result that likes reference numerals have been used to
denote like elements. The one difference that will be
noted in the drive of lower conveyor belt 16a is that the
second sprocket 172 on drive shaft 170 rotates the shaft
132 rather than shaft 123 of lower conveyor belt 16a.
Shafts 132 and 170 are connected by means of a roller
chain 175a and a sprocket 173a provided on shaft 132.
The purpose of independently controlling the
speed of conveyor belts 16a and 16b is to adjust the
crimping ratio between conveyor belts 15a and 15b on the
one hand and conveyor belts 16a and 16b on the other hand.
A number of different means of driving the
conveyor belts will occur to those skilled in the art and
as will therefore be appreciated, the foregoing
description of the drive means is merely exemplary and
other drive means may be adopted without departing from
the scope of the present invention.
r
.:~ ~5
The relative lengths of the conveyor belts may
for crimping purposes be the same or they may be of
different lengths as shown in the drawings. There must of
course be sufficient length for the conveyors to
5 adequately engage th~~ opposite major surfaces of the glass
fiber mat to cause the bunching up of the fibers. In the
embodiment constructed by the applicant, conveyor belts
14a and 14b are approximately four feet in length,
conveyor belts 15a and 15b are approximately nine feet in
10 length and conveyor belts 16a and 16b are approximately
five feet in lE~ngth .
In operation, unsuitable mat is initially dumped
beneath conveyor 15a. Upper conveyor belts 14b and 15b
are adjusted to provide the required gap relative to their.
15 lower counterparts d~=_pending upon product type and desired
thickness and t:o prevent pleating.
In practice, it has been found that the majority
of crimping oc~~urs between conveyor belts 15a and 15b, on
the one hand and conveyor belts 16a and 16b on the other
20 hand, the crimping actually occurring towards the
downstream end of conveyor belts 15a and 15b.
As might be appreciated, the occurrence of
pleating is more oa= a problem when crimping relatively
thin product.
Guide rollers 26 provided in the spacings
between the lower conveyor belts assist in preventing
pleating. Pleating is further suppressed and prevented by
actually adjusting the gap between the pairs of conveyor
belts during the commence of the run. This is done by the
assembly line operator who observes the mat as it proceeds
through the conveyors and is crimped and who then adjusts
the gaps as require<i to prevent pleating. Typically, it
is the gap between conveyor belts 15a and 15b which is
most frequently adjusted as the gap between conveyor belts
16a and 16b is set with reference to the desired thickness
of the end pro~tuct .
When crimping relatively thick mat, the gap
between conve~~or belts 15a and 15b is usually narrowed
... ~~Q~Sz
21
relative to the' gap between conveyor belts 16a and 16b and
may in fact become narrower than the latter as shown in
Figure 1. When crimping relatively thin mat, which is the
more difficult to process, the gap between belts 15a and
15b is widened relative to the gap between conveyor belts
16a and 16b. In al.l events, the relative widths of the
gaps between successive pairs of conveyor belts are
adjusted on they basis of the operator's observations until
pleating is eliminated and are then maintained, subject to
any required minor adjustments, for the balance of the
production run.
From conveyor belts 16a and 16b, the crimped
product is delivered to the curing oven for heating and
curing of the binder to bind the glass fibers together in
the known mannE~r .
It i.s int:ended that the production line as
described herein may form part of and be integrated into
an ordinary production line. When not in use for crimping
product, the upper conveyor belts 14b, 15b and 16b are
simply raised out of: the way and the lower belts are run
at a uniform speed to convey glass fiber mat in the
ordinary way to the curing oven.
It has been observed that crimping occurs
predominantly :in the intermediate portion of the thickness
of the mat betsoeen opposite major surfaces of the mat. At
the opposite major surfaces themselves, the laminations
are less deformed and may even remain substantially
parallel to thE~ opposite major surfaces. It is desired to
minimize the size of: these outer laminar areas to further
increase the ccampressive strength of the product.
Conventional conveyor belts consist of closely
spaced transversely extending cylindrical rods. With
reference to Figure 13, these rods, identified by
reference numeral 2T0, have gaps 271 therebetween. It is
believed that as the glass fiber mat passes between the
conveyors, pori~ions of the opposite major surfaces thereof
are squeezed into gaps 271 to form nodes 272.
-._.
22
As the mat proceeds through the gap, these nodes
are folded over to create what appear to be laminar layers
of fibers at the opposite major surfaces of the mat.
Figure 14 illustrates an endless conveyor belt
for minimizing the formation of nodes. As shown, the
cylindrical rods 270 are replaced by flight bars 100 of
rectangular cross-sectional shape. This construction
obviously minimizes the size of the gaps between the bars
and thereby inhibits the formation of nodes . It has been
found that us~~ of belts of this construction causes or
results in sub:~tantial reductions to the thickness of the
laminar boundary layers at the opposite major surfaces of
the mat.
While the conveyors employed for effecting the
deformation oi_ the glass fiber laminations in Figures 1
and 4 are of a type provided in the form of endless
conveyor belts, it is alternatively possible to employ
driven conveyor rollers for this purpose and Figures 15
and 16 illustrate one suitable form of roller arrangement.
The roller arrangement disclosed in Figures 15
and 16 and indicated generally by reference numeral 40 is
provided between an infeed pair. of conveyor belts 42a and
42b and the caring oven conveyor belts 17a and 17b, and
comprises pairs of upper rollers 44 and corresponding
lower rollers 46 arranged in sets on shafts 48. Each
shaft 48 of thE~ upper sets of rollers 44 is driven at the
same speed as t:he sh<~f t 48 of the lower sets of rollers 46
immediately below it, and each of the succeeding shafts 48
is driven at a speed slower than that of the preceding
shaft 48. Since thE~re are nine pairs of shafts 48, this
roller arrangement provides eight stages, i.e. one stage
between each pair of: shafts 48, at which the glass fiber
laminations are progressively deformed until at least a
major portion therE~of extends in the direction of the
thickness of the glass f fiber mat .
The deformation of the glass fiber laminations
in the above-described manner produces a product which, as
will be apparent from the above discussion, exhibits an
.~3~ p7~2
23
improved compression strength in a direction perpendicular
to its opposite major surfaces. A sample of the crimped
product is illu.strate~d in Figure 17 and as will be seen, a
majority of i~he glass fibre laminations have been
reoriented relative to the opposite major surfaces of the
mat.
The product is therefore particularly suitable
as roof insulation board.
However, the present invention may also be
employed with advantage for other glass fiber products
requiring enhanced compression strength, for example pipe
insulation. It has also been found that wall insulation
batts manufactured by the present method and apparatus
have the advantage of exhibiting improved recovery of
their thicknes~~ when released from a compressed, packaged
state and can therefore be more compactly packaged, with a
consequential reduction of their space requirement for
storage and transportation.
The present invention is not restricted to the
details or features of the above-described embodiments
thereof but may be varied within the scope of the
following claims.
