Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
FIELD OF TH~_INVENTION
This invention relates to a device for assuring
better lamination of film material. When webs of film material
are fed to laminating rolls without the use of the present inven-
tion, they generally have different amounts of stretch thereon.
Thus, when the laminated material relaxes, it may result in too
much curl or warping. The present invention uses the concept
that the width or thickness of the web is proportionately re-
lated to the amount of stretch thereon and, therefore, a vhoto-
electric scanner is used for measuring the width of the web and
imparting a signal to a pneumatically controlled dancer arm.
DESCRIPTION OF THE PRIOR ART
Photoelectric sensing devices are shown in United
States Patent No. 2,088,984 to Tandel. The position of the web
is measured rather than the thickness thereof.
In the past, load cells and dancer arms have been
used to control the tension on a web being fed as disclosed in
United States Patent No. 2,753,128, as well as in Japanese Patent ¦
No. 44-12163 and British Patent No. 1,371,760.
The United States Patent Mo. 2,627,296 to Secrest
discloses an apparatus includ means for adjusting the tension in
~1 a web of fabric.
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In United States Patent No. 3,239,161 to Dutro et al
there is disclosed a drive control mechanism which dispenses an
elongated web of material with the spped and tension thereof being
adjustable.
United States Patent No. 3,510,374 to ~alker discloses
a control apparatus for sensing a property of a moving web and
adjusting the moving web so that the desired property is uniform
throughout the web.
In United States Patent No. 3,107,679 to Pawlowski,
there is disclosed an automatic tension control device which
utilizes either pneumatic or electrical circuitry to maintain the
tension in a web of material substantially constant.
The United States Patent No. 3,762,125 to Prena dis- I
closes a device for controlling the lamination of one material
onto another material which utilizes a photocell 50, which is
responsive to indicia 48 on the film "F" which sends the infor- ¦
mation to a control box 34 of a clu,tch 39, which controls the
stretch rolls 38a and 38b to thereby keep the two webs lined
up with one another.
United States Patent No. 4,347,993 to Leonard dis-
closes a tension monitoring and controlling means which includes
a controller responsive to outputs of the tension sensing trans-
ducer thereof a reference tension selector for controlling
~j torque applied to the tension control roll to thereby control
¦ the web tension.
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The present invention has for its concept the use of a
photo-electric scanner for scanning the width or thickness of a
web of material to provide an input into a pneumatic actuator for
a dancer arm to adjust the tension on a web of film material. The
position of the dancer arm is in turn sensed by a sensor and
computer which provides a signal to a motor operating an endless
belt engaqing the web of material to resist pulling of the web
from a supply roll. Thus, the stretch in the web of film material
can be equalized with that of the predetermined stretch in another
web of film material when both are fed to laminating webs so that
there will be no warping of the laminated product.
The present invention therefore provides a device for
testinq and adjusting the amount of stretch in a first web of
material for corresponding the amount of stretch in said first
material to that of the predetermined stretch in a second web of
material comprising a pair of laminating rolls, feed means for
feeding said first and second webs of material to said laminating
rolls, a supply roll for said first material, unwind means for
applying an initial tension on said first web of material,
scanning means for scanning the width of said first web of
material, a dancer arm having an idler roll about which said first
web is entrained, control means for loading said clancer arm upon
signal from said scanning means, and sensor and computing means
connected to said control means and said unwind means for applying
initial tension on said first web of material and said control
means to adjust the tension on said first web of material so that
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said material has a stretch equal to the predetermined stretch on
said second web of material.
This invention also provides a device for testing and
adjusting the amount of stretch in a first web of material for
corresponding the amount of stretch in said first material to that
of the predetermined stretch in a second web of material
comprising a pair of laminating rolls, feed means for feeding said
first and second webs of material to said laminating rolls, a
supply roll for said first material, unwind means for applying an
initial tension on said first web of material, scanning means for
scanning the width of said first web of material, a dancer arm
having an idler roll about which said first web is entrained, a
pneumatic cylinder having a piston therein, said piston being
connected to said dancer arm, compressor means actuated by said
scanning means for actuating said piston to load said dancer arm,
and sensor and computing means connected to said control means and
said unwind means for applying intitial tension on said first web
of material to vary said unwind means and said control means to
adjust the tension on said first web of material so that said
material has a stretch equal to the predetermined stretch on said
second web of material.
By way of illustration but not limitation, an embodiment
of this invention will be hereinafter described, with reference to
the drawing, in which the Figure is a schematic diagram of an
embodiment of this device for adjusting the stretch in a web of
film material.
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DETAILED DESCRIPTION OF TH~ INVE~TION
With continuing reference to the accompanying drawing,
there are provided a pair of laminating rolls 10 and 12 between
which two webs 14 and 16 of film material are drawn for lamina-
tion thereof.
The amount of stretch on the material 16 is predeter-
mined by measurement or other means. The device according to the
present invention is for equalizing the stretch in material 14
with the stretch in the material 16 utilizing the fact that the
amount of stretch will be proportionate to the width of the film
material 14.
The material 14 is drawn from a supply roll 18 by
driven feed rolls or by the laminating roll nip. Initially, the
tension on material 14 is controlled by a dancer arm 32 loaded
by a pneumat:ic controlled piston 46. The speed of the endless
belt 26 driven by motor 28 is used to maintain the dancer arm in
an operating range.
The material 14 is passed by roll 20 and then passes
about an idler roll 30 on a dancer arm 32 pivotally mounted as atl
j~ 34. The material 14 is then passed by rolls 22 and 24 and pulled
by the laminating rolls 10 and 12.
A photoelectric scanner 40, including a photo-elec- !
tric cell and signalling means, is positioned to measure the width
of the material 14 after passing about the idler roll 30 and is
electrically operatively connected to a pneumatic actuator 42,
including a pr~ssure regulat ~4 aonneated to an air or pneu~ati~
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cylinder 46 for controlling the force of a piston 48. Thus, the
signal from the scanner 40 determines the load on the dancer arm
and hence the tension on the material 14 and the amount of stretch
thereof.
There is a rotational sensor or potentiometer 50 for
providing an electrical signal based on the rotational position
of the dancer arm so as to provide a signal to a computer 52 or
micro-processor associated with the motor 28.
Thus, the speed of the endless belt 26 is controlled
by motor 28 dependent on the signal from the rotational poten-
tiometer 56 to control initial stretch on material 14 so that the
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stretch on the material 14 will be the same as the stretch on
i, material 16 being fed to laminating rolls 10 and 12.
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