CA1160320A - Laminated edge control device - Google Patents

Abstract

LAMINATED EDGE CONTROL DEVICE

ABSTRACT OF THE DISCLOSURE
An edge control apparatus for trimming the excess plastic film that projects laterally from the edge of a backing material in a calendering operation, comprising a cutting tool, at least two signal producing sensing devices positioned on each side of the tool and mounted on a moveable support containing the cutting tool such that the edge of the backing can be accurately tracked after lamination but just prior to the laminating material traversing the cutting tool. The disclosed apparatus allows for improved accuracy in tracking the edge of the backing material and, therefore, provides a more accurate means for removing the projecting plastic film for reuse without removing the backing material.

Description

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L~MI _ ED EDGE CONT~OL DEVIC
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In the process of forming laminates oE a thexmo-plastic film, as for example, polyvinyl chloride and a fabric backing, some of the film will generally project beyond the edges of the backing. It is desirable to trim the excess film from the bac~ing for subsequent recyling and reuse. In such operations, excess material cut from the backing cannot be recycled for subsequent use if backing material is included therein.
There has been disclosed in the prior art, web edge control devices, for use in calendering operations, which utilize photoelectric cells to guide a cutting knife relative to the edge of a backing or webbed material.
United States Patent No. 3,753,381, for instance, dis-closes a method of cutting or grooving corregated paper-board material which comprise; positioning two photocells on each side of a corregated web and ahead of a cutting tool wi-th one cell on each side focused on the edge of the web and the other cell focused on a stationary light background adjacent to the edge of the web. If/ therefore, the web shifts laterally, the photocells on either side of the web will focus on the light background or on the web. Additionally, -the photocells of the disclosed invention are positioned on a laterally moving carriage which electronically connects $o another laterally moving carriage containing the cutting tool by potentiometers which provide for moving one carriage to a position corresponding to the other carriage when the two positions are not the same.

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United States Patent No~ 4,070,9 discloses an apparatus for s~uaring or trimming the edges of the uncured cover of an industrial belt such that an ade~uate but not excessive amount of the cover material is removed from the belt.
This is accomplished in the disclosure by positioning a photocell on either side of the belt edge to track ~he edye of ~he uncovered carcas r and positioning a pair of trimming blades such that they are laterally displaced by mechanical drive means responsive to signals obtained from the photocells.
The disclosed lateral spacing of the cutting knife is limited to one-half the algebraic sum of the lateral deviation of the edges of the carcas sensed by the photocells~
~ inally, British Patent No. 681,000 discloses trimming the edges of a continuous length of material by removing excess plastic composition projecting laterally of the backing material. The disclosed invention.utilizes a cutting knife disposed on each edge of the coated matérial~
The edge of the uncoated backing material is allowea to traverse a signal-producing device ~such as a photocelL) which tracks the lateral position of ~he edge and.relays information by means of a moving recording medium to the cutting knife, which is caused to move laterally to a position adjacent the edge of the material after the coa~ing has been applied.

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,' In none of the above cited art: is there disclosed a process whereby the edge of the mate.rial is photoelectrically sensed after the coating was applied (after lamination is completed) and just prio.r to traversing the cutting tool such that a substantial time lag does not develop between tne sensing ~nd the cutting of the.desired edge of the material. Neither is there disclosed, positioning the signal producing deyice on the same unit as the la-terally moving cutting tool such that both are displaced as a unit.
Finally,.the Prior Art fails to disclose utilizing more than one signal producing sensing device to trac~ the edge of the laminated material such that both devices are sited on the moving laminated edge of the material just prior to the edge traversing the cutting tool.
SUMMARY OF ~E ILWENTION
The instant edge control device-was de~igned pri-marilytO remove the excess filr.. of a plastic laminate, laterally projecting from a backing material during a calendering operation, without remo~ing the fahric. It is desirable, for economic reasons to trim off.as much of the excess film as possible, cut it into small pieces, and recycle for reuse.
In furtherance of this objective, it is desirable to precisely determine -the edge of the material being trimmed,. and to eliminate any appreciable time lag between the sensing of the edge and the time at which the edge traverses the cutting tool.

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-6~32~ c The time lag is a feature present in known prior art devices. The invention in its broadest aspect i5 an apparatus or device for trimming edge of a continuous length of material which comprises: a support; a cutting tool mounted on said support; at least two signal pro~
ducing sensing devices mounted on the support; one on each ' side of the cutting plane of the cutting tool, the support I with the cutting tool and the sensing devices being mounted I on a moveable carriage; the sensing devices, being positioned i to sense the edge,of the material just prior to its j traversing the cutting tool, and to produce a signal cor-!: responding to the position of the sensed edge; and means for I laterally displacing the moveable carriage to position the ' cu~ting tool adjacent the edge o~ the material as sensed by f the sensing device.
} More precisely, the invention comprehends an edge trim control device for trimming plastic film ~ ,projecting laterally from a backing material in a calen-¦ dering operation, which apparatus comprises a support ,~containing a cutting tool and positioned on a mo~eable carriage; at least two photoelectric cells positioned one on each side o the cutting plane of the cutting tool and - mounted on the support such that an edge,of the backing material after lamination lies between them and is optically sensed just prior to the laminate tr~e~sing ~he cutting tool, t~

C-55~5 J~ " ~ ' ` ( ~ 3Z~ ~ -~ 5 -photoelectric cells being adapted to each produce a signal corresponding to the position of the sensed edge and means for laterally displacing the moveable carriage to position the cutting tool adjacent the edye as sensed hy the photoelectric cells.
Fuxther objects and features of the invention ~isclosed herein will become apparent from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 isan illustration of one embodiment of the edge control device; and FIG. 2 is a schematic view of the apparatus of FIG. 1 further illustrating the circuit controlling the function of the apparatus.
DETAILED DESCRIPTION OF THE INVENTION
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Referring now to FIG. 1, which presents one embodiment of the invention, there is presented calender roll 5 and laminat-ng roll 6 through the nip 7 of which the laminate 8, comprised of a vin~l film 9 superimposed ., on a fabric backing 10, passes in the direction indicated by the arrow 11. The edge control device 12 in this embodiment is positioned at one edge of the fabric laminate such that a cutting edge 13 of the fabric backing lies between two photoelectric cells 14 and 15. The cutting edge 13 in this specification refers to the edge of the fabric beyond which the plastic projects. Although, photoelectric cells are the signal producing de~ices used in this embodiment it should be xecognized that other signal producing means can be substituted as the methoa for accurately tracking the edge of the Eahr:ic bc~cki.ng.

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The photoelectric cells 14 an~ lS of the embodiment of the invention shown in FIG. 1 are mounted on a support 16 in which a cutting tool 17 is positioned. ~he photocells are positioned one on each side o the cutting plane of the cutting tool 17. The cutting plane should be understood to refer to the path between the photocells that would be cut if the line of cut of the cutting tool was uniformly extended. Any suitable cutting means may be utilized. The tool 17, in this instance is an air actuated cutting knife commercially available from the Cameron-~aldron Division of Midland Ross and is positioned in this embodiment in a caster type mount 18, comprised o~
a dovetailed steel axle mount 19, riding on a vertical steel shaft (not shown) within the support 16. This novel caster mount method of positioning the tool 17 allows for the lateral motion of the tool without wrinkling or jamming ~he continuously moving plastic laminate due to its ability to shift at the angle of cut. The knife used should, of course, be suited to the materials being cut and the surface on which they are cut. A wooden or plastic knife would be appropriate on a calender roll t~hereas in cold laminating a steel knife would be suitable. A laser which generates a light beam capable of cutting the projecting plastic from the edge of the fabric can be used as the cutting tool.
The support 16, as shown is screwably mounted on plate 20 which in this instance is an aluminum plate that is in -turn bolted to a moveable carriage 22 capable of moving the support 16 containing the cutting tools and the photoelectric sensing devices 14 and 15 in response to the lateral shift of the cutting edge of the fabric backing as detected by the photocells.

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The moveable carriage 22 can utilize any drive means capable of laterally shifting the carriage in proportion to a control signal. In the embodiment shown a Velmex Unislide motor assembly 23 of which the carriage 22 is a part~ is utilized for this purpose.
The assembly 23, commercially obtainable from Velmex, Inc., Bloomfield, New Jersey, contains a lead screw 24 for postioning the carriage. The screw is sleeveably positioned through an adjustable split nut 26 which is secured to the carriage and extend therefrom. The lead screw 24 is adjustably clampe~ within the split nut 26 by an adjustable lead screw nut 28. Other features of the assembly 23 which are not shown are limit switches, control rods and adjustable columns for limiting the range of mo~ement of the carriage.
The functioning-iof the edge control device 12 can be best described with reference to FIG. 2. The outer photoelectric cell 14 and the inner photoelectric cell 15 each combine a light source and a photocell lphotodetector~ mounted parallel to one another, in a single unit. These signal producing sensing devices are utilized in conjunction with a control unit 30 containing potentiometers 31 which set the operable thresh~ld of reflected light~r each-photocell, and with other control - circuits 33 ~nd 34)which process the signal received from each photocell through amp~sfier 34 tha~ compares the separate signals, and where necessary, transmits a signal to a thyristor or.triac-drive 35 that operates~;the reversible DC motor 36 to laterally shift the moveable carriage proportional to, and in the direction of ~he sensed lateral shifting of the cutting edge 13 of the fabric backing.
In addition to the potentiometers 31, the control unit 30 houses; control modules 32 which recei~e the signals transmitted by the photocells 14 and 15 and wh.ich * Trademark ~6(~32~ ( powers the light emitting diodes of the pho-tocells; optical isolaters 33 which allow the control modules 32 to operate at true ground, isolated from the following thyristor circuit 35; an amplifier or logic circuit 34 which co~pares the received signals, and where there are operative variations produces a signal propor~ional to the lateral shifting of the cutting edge 13 of the backing;
and a triac-drive 35 ~th~ristor) which in response to the signal received from the amplifier 34 operates the reversible DC mOtQr 36, a.part o~ the motor assembly 23.
The device 12 therefore operates as follows:
The potentiometers are.adjusted to set the threshold of reflected.light which would induce an output signal in the photocells. Each sensor is adjusted so tha-t its operative threshold lies between the level of -the light reflec-ted ~rom the fabric (designatea-off) and that reflected by the bare plastic.~designated-on).
The device 12 functions as shown in the following table and is fully described below with reference to FIG. 2 an~ the Table.
TABLE
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, PHOTOE~ECTRIC CELLS ¦ LOGIC CIRCUIT ~ -- .- - SEM5ED POSITIO~.i-- CORRECTIVE
OUTER ~ INNER I ~F ~UTT~NG EDGE ~TION~OF--CAPRIAGE
.... __ .. _...... .. ~
On Off On Cutting Edge None Off Of~ Both Sensors Move carriage to-.- ; ~ighte~ on Fabric wards plastic . (outside) See FIG~ ~
On On Both sensors Move carriage to-Sighted on plastic wards fabric . (inside) See FIG. 2 When the knife 17 is in the cor:rec-t position w.i-th respect to the fabric cuttiny edcJe, th~ photoelecl:r:ic cells 1~ ~nd 15 would b~ s:i~hted r~5pectively on the inne~ edye 37 o~ the ~ab.r;ic ~abric), ancl on the o~lte;r ~clye 38 o.~ the E~bric C~SSG5 ' ' J `\~ .

` ` ( ~ 3'~0 ~ -(plastic). In this position, the outer photodetector 14 will be on and the inner photodetector 15 will be off and -the logic circuit receiving and comparing the signals received from both photocells will not, in accordance ~i-th its logic circuitry, ~eed a corresponding signal to the thyristor to cause the motor to al-ter the position o the knife ancl photocells. When, however, as sho~n in the abo~e Table, both the inside and outside sensors transmit signals indicating that both are sighted on the fahric (of~), the position of the fabric cutting edge 13 will be outside.
In such instances, the logic circuit will transmit a signal to the thyristor which will cause the DC motor to make the necessary corrective motions by moving the leaa screw 25 which will position the carriage 22 by moving it out towards the projecting plastic until both photocells will again be properly citea on the inner 37 an~ outer 38 edge (cutting edge 13) of the ~abric backing, an~
accordingly the knife will be again correctly positioned at the cutting edge of the backing.
When the position of the laminate is such that both photodetectors are focused on the plastic film--both detectors on--the siynal received by the respective control modules 32 and transmitted to the logic circuit 34 will cause a correcting signal to be ed to the thyristor 35 thereby operating the motor 36 to move the carriage 22, by means of the lead screw 25 r inwardly (towards the fabric backing) until the photoaeteetors are again correctly positioned to focus.on.the inner 37 and outer 38 edge (cutting edge 13) of the fabric backing.
Any deviation from the correct cuttin~ position will therefoxe cause the photocel:ls to be both on or both off.
The photoelectric cells utilized in this e~bodi~
ment are capable o detectinc~ the edqe of a white-on-white laminate with a resolution of better than 1~32" tO.~8 cm).
In the embod.iment -the photocells 1~ and lS and -the con-trol rnodules 32 containinq internally loca-ted pcotentiometers ( ~ 3'~

were commercially obtained from Frost Controls, Inc., Cumberland, R.I. The control modules 32 were moc~ified in the embodiment shown to locate the potentiometers 31 externally of the control modules as sho~ in FIG~ 2 to allow for more facility in making potentiometric adjustments.
.The response of the electrical signals and the motor to the amount of reflected light detected is rapid when compared to the speed with which the laminated material continuously moves past the cutting tool. Of course, the response feed of the signals can be varied by built-in time delays. It is also possible to de-termine the position of the edge of a backing materîal within a laminate using photodetectors, by means other than by measuring reflectivity. The edge, for instance, can be distinguished using photodetectors.by means of photo-electrically counting the fibers of the differing materials, or by measuring the light returning to the..
detectors after scattering,or by measuring the difference in the reflec~ance of polariz~ light caused by the differing materials. It should be evident, therefore~
-that the disclosed-invention contemplates a device in - which the materials comprising the laminate can be varied - at will,since the detection of the cutting edge requires only-some--measurable.differences in the response . received by the photoelectric cells due to the differences in the materials comprising the laminate.
I When the edge control device is functioning,the I knife.is desirabLy positioned so that the blacle moves radially towards the roll when air pressure is appl:ied~ ~ soleno:icl air valve (not shown) iS u5ed in -thi.s embodiment to apply air pressure to the knife when energi2ed, and releases pressure .

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~ 6(33~ ( from the knife when de-energized. When the edye control device is functioning, air is continuously applied to the knie by means of an "on/off" switch located on a front panel (not shown) of the controller unit which applies power in the solenoid valve in the "off" position. Various switches and adjustmen-t means can also be provided for the embodiment shown (on the panel) for operatiny the edge control device in an automatic or manual mode, as for instance, a main power.switch which makes AC power available ~or -the operation of the edge control device, the air l'on/off"
switch, mentioned above which supplies power to the solenoid valve for activating or deactivating the cutting tool, a controller "on/off" switch which supplies power to the photoelectric control modules and to the thyristor or motor control circuit; an auto-manual switch which allows for the selection of the automatic o~ manu~l operative control as desired; a stop "left-right" momentary toggle switch which powers the DC motor to move the carriage left or right as desired when the cutting device is manually operated; a pair of "on/off" switches whi~h are the adjustment switch for the potentiometersr and .'therefore, preset the threshold of reflected light which turns the sensors on; and left-right indicator lights which visually indicates direction of movemen~
of the carriage, and can be used to adjust the potentiometers when the device is manually operated (they indicate direction of motion as controlled by the photoelectric sensors).
One skilled in the art will appreciate tha-t the above mentioned easily accessible switches and adjustment , , , . ~, ` ~ 32~

- 12 - , means in the embodiment shown for.operating the dev.ice are primarily provided for the purpose of illustrating the invention, and should not be considered requisite features of the disclosed inventionO It wi].1 also be apparent,to those skilled in the art t,hat various changes and modifications may be made herein without departing from the spirit and scope of the invention.

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Claims (8)

WHAT IS CLAIMED IS:

1. An edge control device for trimming an edge of a continuous length of material which comprises: a support;
a cutting tool mounted on said support; at least two signal producing sensing devices mounted on the support one on each side of the cutting tool's cutting plane, the support with the cutting tool and the sensing devices being mounted on a moveable carriage; the sensing devices, being positioned to sense the edge of the material just prior to its traversing the cutting tool and to produce signals cor-responding to the position of the sensed edge; and means for laterally displacing the moveable carriage to position the cutting tool adjacent the edge of the material as sensed by the sensing device.

2. The device of Claim 1 wherein the cutting tool is a laser.

3. The device of Claim 1 wherein the sensing devices are photoelectric sensors.

4. An edge control device for trimming plastic film projecting laterally from a backing material in a calendering operation which comprises; a support containing a cutting tool and positioned on a moveable carriage; at least two photoelectric cells positioned one on each side of the cutting tool's cutting plane.and mounted on the support such that an edge of the backing material after lamination lies between them and is optically sensed just prior to the laminate traversing the cutting-tool, the photoelectric cells being adapted to produce a signal corresponding to the position of the sensed edge; and means for laterally displacing the moveable carriage to position the cutting tool adjacent the edge as sensed.

5. The means for laterally displacing the carriage of Claim 1 or Claim 4 which comprises a lead-screw driven by a reversible DC motor.

6. The edge control device of Claim 1 or Claim 4 wherein the cutting tool is positioned in a caster mount.

7. The device of Claim 4 wherein the edge is optically sensed by the difference in the reflec-tivity of the backing material and the plastic film.

8. The device of Claim 1 or Claim 4 wherein the cutting tool is a knife.