Method of transferring mat from a forming surface station to a bonding station

A fiber glass mat making process is described which utilizes an improved method of transferring unbonded mat from a mat forming chain to a bonding station on a continuous basis. The system involves passing the unbonded mat from a continuous conveyor surface to a roll which has on its surface a draped conveyor chain rotating around the roll but driven by the roll on which it is draped. By permitting the draped chain to hang freely below the roll and to rotate with the roll stray strands falling between the conveyor surface and the roll are returned on the draped chain to the feed end of the bonding station. Means are also provided to maintain the draped chain centered to insure that mat is delivered to the bonding station in a straight line from the conveyor surface.

BACKGROUND OF THE INVENTION 
In a process described in U.S. Pat. No. 3,883,333, continuous glass fiber 
strand mat is made on a forming conveyor and is fed to a mechanical 
needler which imparts mechanical integrity to the mat by rapidly 
penetrating the mat with barbed needles to thereby bond the glass strands. 
In the system shown in the above patent, two conveyors are employed, one 
on which mat is first formed and a second one which moves the mat through 
the needling machine. Occasionally, the mat being transferred from the 
forming chain to the needling machine falls between the main conveyor roll 
and the drive roll of the second conveyor which causes the mat to tear or 
become fouled on the conveyor roll on the second conveyor. If the fouling 
is particularly bad, this necessitates considerable downtime to move the 
needler drive roll so that the glass can be cut off of the main conveyor 
roll or the second conveyor rolls so that the process can be restarted. 
Further, considerable difficulty has been encountered in keeping the 
unbonded mat transferred from the main conveyor to the needler conveyor in 
a straight line and the mat material if it is fed into the needler in an 
off-center or non-straight mode causes excessive waste out of the needler 
due to the fact that most needled mat is edge trimmed to a precise width. 
In an attempt to solve the problem of mat transfer, a system was proposed 
to utilize a grooved roll rather than a second conveyor to transfer mat to 
the needling device. The grooves in the roll were provided with fingers to 
lift the mat as it passed over the roll surface to assist in the transfer. 
This system failed in that glass strands tended to stick to the fingers 
and wrap around the needler feed roll causing more wraps than were 
experienced with the double conveyor belt system of the aforementioned 
patent. 
Thus, a need still existed to provide an efficient method of transferring 
continuous strand mat from a forming conveyor to a bonding operation, such 
as a needling machine, which would minimize roll wraps at the transfer 
point and which would also provide a system that minimizes the downtime 
for the machinery should a roll wrap occur. There was also a need to 
provide system for conveying the mat from the mat forming conveyor to the 
bonding station in a straight path to minimize waste caused by 
misalignment. 
The Invention 
In accordance with the present invention a method is provided which permits 
continuous strand mat formed on a conveyor to be passed to a bonding 
station such as a needling machine with a minimum amount of difficulty. 
Thus the system is such that roll wraps between the main mat forming 
conveyor and the needling device for example, are kept to a minimum, while 
at the same time, the mat entering the needling device is kept in a 
straight line. Further, the simplicity of the method permits a roll wrap, 
should it occur, to be corrected quickly and efficiently, substantially 
reducing the downtime experienced with a double conveyor system such as 
described in the aforementioned U.S. Pat. No. 3,883,333. 
The Present Invention 
In accordance with the invention, unbonded continuous strand mat which has 
been formed on a continuous belt conveyor is moved along the conveyor to 
the end thereof and is transferred to a conveyor chain surface which rides 
on a single roll. The chain surface is part of an endless belt that is 
draped over the single roll and forms a loop below the roll. The chain is 
of a weight such that the pressure it exerts on the surface of the roll is 
sufficient to cause the chain to rotate with the roll in continuous 
movement when the roll is rotated. The ends of the chain drape are 
maintained in a straight line alignment on the roll surface by forcing the 
chain as it rotates between two guides located below and on both sides of 
the rotating roll over which the chain is rotating continuously. 
The roll over which the chain is riding has a roller above it to apply some 
pressure to the continuous strand mat passing between the chain and the 
pressure roll. The chain draped roll is positively driven and can be 
varied in speed so that in conjunction with the pressure roll associated 
with it the conveying speed of the chain draped roll can exceed the main 
conveyor speed to provide at the point of transfer of the mat drafting of 
the mat coming off the main conveyor to control its density as will be 
described more fully hereinafter. 
It has been found that the chain drape permits loose strands falling 
between the main conveyor and the draped roller to be picked up by the 
drape chain and they return to the chain surface rather than passing onto 
and fouling the main conveyor chain. Further, if a wrap does occur, the 
roller with the chain drape can be moved if necessary to permit the mat to 
be cut without the difficulty that this involves using a second conveyor.

As shown in FIG. 1, a plurality of fibrous strands 11a, 11b, 11c, and 11d, 
are fed to a conveyor, generally indicated as 12, which has an endless 
belt 13 which is continuously moved around rollers 14 and 15. A pressure 
roll 17 is placed on the mat 16 above the roller 15. The roller 15 in the 
main conveyor drive roll and pressure roll 17 is interconnected (not 
shown) to roll 15 to provide equal speed of both rolls 15 and 17. The mat 
16 is passed between a second set of rolls as it leaves the belt 13. This 
set of rolls has a drive roll 19 and a free-wheeling pressure roll 20, 
aligned in parallel with each other. The pressure roll 20 engages mat 16 
as it passes underneath it and applies pressure to mat 16 as it rides 
across the surface of a belt 22 which is draped across most of the width 
of the roll 19. The mat 16 after leaving the surface of belt 22 enters the 
needler 25 which is reciprocated continuously in an up and down fashion as 
indicated by the arrows on the drawing. The needles 26 are barbed and in 
penetrating the mat 16 in its passage through the needler 25 cause the 
strands in the mat 16 to move and entangle each other resulting in a 
mechanical bonding of the mat 16 in the needler 25. The mat 16 as it 
leaves the needler is passed between a free-wheeling pressure roll 27 and 
over a drive roll 28 and around a tension roll 29 which is also 
free-wheeling. The mat is then passed to a collection station (not shown) 
for packaging. 
As shown in FIG. 2, roller 19 has an endless belt 22 draped around it. In 
the preferred embodiment this belt takes the form of a stainless steel 
mesh. The roller is driven off of shaft 19a which is connected to a belt 
and pulley arrangement associated with a suitable motor, not shown, but 
which is conventional in the conveyor art. Guide brackets 30 and 31 are 
placed near both ends of the roll 19 and below it to maintain the endless 
belt 22 centered on roll 19 to insure the mat 16 moves into the needler 25 
in a straight path from the conveyor 12 and across roller 19 and its 
associated belt 22. 
In the practice of the invention, strand mat may be prepared by feeding 
strands to the surface of the mat in the manner described in U.S. Pat. No. 
3,883,333, which is incorporated herein by reference. Thus, to provide a 
glass mat, for example, fiber glass strands formed from a plurality of 
molten glass sources, known in the art as bushings, are traversed across 
the width of the conveyor surface to lay down the strands one above the 
other to establish a given density of mat on the conveyor surface. If a 
mat of synthetic fibers is being formed, the fibers from a spinnerette are 
fed in similar fashion as they emerge from the spinnerette. If desired 
strands can be traversed from packages of strands already formed by 
feeding the strands from the package and traversing them across the 
conveyor surface in a similar manner to the way strands are pulled from a 
bushing or spinnerette. 
The endless belt 13 of the conveyor shown herein is preferably constructed 
of stainless steel mesh with the mesh opening being sized so that the 
strands ride on the surface thereof and penetration of strand into the 
openings of the mesh is minimized. Similarly the drape belt 22 is 
constructed of stainless steel mesh with the openings being small enough 
to prevent strand from entering them but open enough to permit cleaning 
with fluid spraying of accumulated dirt sizing or binder material normally 
present on strands used to manufacture mat products. Thus, both the main 
conveyor belt and the drape belt can be readily cleaned and serviced while 
providing a continuous surface for mat formation and transfer without 
becoming fouled by entrapped strands. 
In a typical operation of the instant invention as shown in FIG. 1, a mat 
was formed by traversing a plurality of fiber glass strands from glass 
fiber forming packages across the width of conveyor 12 using a trasversing 
mesh as shown in U.S. Pat. No. 3,883,333 to provide a mat having a density 
of about 6 oz. per square foot on the endless belt 13. The endless belt 13 
was a wire mesh chain having a wire mesh density of 42 links per square 
foot by 38 links per square foot. Drive roll 15 driven to provide a speed 
of 8.4.sup..+-. 0.2 feet per minute. The distance between roll 15 and roll 
19 was 4.5 inches and roll 19 was positioned slightly below roll 15 to 
provide an inclined path for the mat 16 passing from conveyor 13 to the 
chain drape 22. Pressure roll 17 was an 81/2 inch diameter hollow steel 
roll. Feed roll 19 was a 61/2 inch diameter steel roll having a chain 
belt, identical in mesh configuration to the belt 13 draped over its 
surface of roll 19 to a point below the main conveyor chain 13. Pressure 
roll 17 was a solid steel roll 7 inches in diameter. Roll 19 and roll 28 
at the exit of the needler were positively driven by motors, not shown, to 
provide speed to the mat 16 passing through needler 25 of 14.4 ft. per 
minute. During several hours of operation of this unit, the glass mat 
successfully transferred without wraps on a continuous basis from the 
conveyor belt 13 through needler 25 with ease. Strands that tended to drop 
between the conveyor belt and the chain drape were observed to be caught 
on the surface of chain 22 and were pulled back onto the nip point between 
rolls 20 and 19 and moved through the needler. While the bonding operation 
is shown as a needler, it can of course be a chamber where resin is 
applied to bond the mat. 
While the invention has been described with reference to certain specific 
embodiments thereof it is not intended to be limited thereby except 
insofar as appears in the accompanying claims.