Method And Apparatus For Registering Two Separate Webs Of Wrapping Material

Abstract

A packaging machine adapted to maintain plural webs in registry with a product, including electric eyes disposed in sensing relationship to each web. An infeed conveyor supplies the product. A cam and switch responds to the position of the product relative to the webs one or all of which may be stretchable, and a web brake control system is responsive to signals from the electric eyes and the cam to brake one or all of the webs in order to maintain the webs in registry with one another and the product. The method of maintaining webs of film in registry is also disclosed.

Description

BACKGROUND OF THE INVENTION

This invention pertains to a method and apparatus for registering two or more separate webs of wrapping material, and more particularly, to webs of wrapping material films, one or more of which may be tensionable, such as cellophanes, laminates of cellophanes, polypropylene laminates, polyester laminates, polyvinyl chloride films, and the like.

PRIOR ART

In the continuous manufacture of packages of the type having a pair of webs forming the package, difficulty has been encountered in forming a package in which the webs are in registry with each other, and with the product.

In machines of this general type, a continuous composite ribbon is manufactured by combining two continuous webs or strips of the appropriate configuration which are secured to each other after which the continuous ribbon is cut into individual packages or containers. The two webs require careful and continuous sensing of the relative positions of the webs in order to prevent misalignment or lack or registration of web to web or product to webs. Either or both of the webs are provided with imprinting or embossing and the product is sandwiched between the two webs. Due to fluctuations in the physical properties of the web material as influenced by its composition, structure and surrounding atmospheric and temperature conditions, and due to variations in some of the products, it is extremely difficult to synchronize the movement of the printed webs relative to each other so as to assure that the indicia will, at all times, remain in proper position with regard to individual packages.

When the imprinted web or webs move out of registry, subsequent cutting of the continuous strip into individual packets of dispensing containers results in a mutilation of the imprinted message which seriously detracts from the appearance, informative nature, saleability, and usability of the package.

Because of this problem, a prior art solution has been to form the continuous strip from two webs wherein the imprinted or embossed indicia has a spacing frequency of greater than two per length of the final package to assure that at least one complete message or design is incorporated somewhere on each package. In the majority of instances this is not a satisfactory solution as it seriously detracts from the package appearance. Alternatively, the continuous strip may be formed of two unprinted webs, and the individual packages cut therefrom are thereafter subjected to a second operation in which an imprinted or embossed overlay web or label is placed attached to the face of each individual package. The latter practice is extremely costly, tedious, time consuming and substantially detracts from the efficiency and economy of packaging.

SUMMARY

It is, accordingly, a principal object of the present invention to overcome the foregoing and other deficiencies and disadvantages of the prior expedients and to provide a novel method and apparatus for registering two separate webs of wrapping material and accurately controlling the registration of imprinted or embossed indicia on one or both of the webs relative to the resultant package.

Another object of the present invention is to provide a new method and apparatus for registering two or more separate webs of wrapping materials for accurately controlling the registration of imprinted or embossed indicia on each of the webs relative to the resultant product.

A further object of the invention is to provide a new method and apparatus to effect registering of one of two webs to the product and the registration of the two webs with each other.

Still another object of the present invention is to provide a method and apparatus for registering two or more separate webs of wrapping material incorporating sensing means, i.e., electric eyes, responsive to the position of each of the webs, a cam registration system responsive to the position of the product, and a braking system for each of the webs responsive to signals from the electric eyes and cam switch.

Many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which preferred structural embodiments incorporating the principles of the present invention are shown by way of illustrative example.

On the drawings:

FIG. 1 is a perspective view of a packaging apparatus to which the present invention is applicable;

FIG. 2 is a schematic elevational view of the packaging apparatus of FIG. 1;

FIG. 3 is a fragmental side elevation view of the packaging apparatus shown in FIGS. 1 and 2;

FIG. 4 is a partial sectional view taken along the line IV-IV of FIG. 3;

FIG. 5 is an end view of the packaging apparatus of FIGS. 1 and 3 with the supply rolls removed;

FIG. 6 is a block diagram of the control circuitry for use with the present invention;

FIG. 7 is a schematic diagram of the circuitry represented by block WEB BRAKE CONTROL of FIG. 6; and

FIGS. 8 and 9 are some alternative embodiments of web brake control circuits having reference to FIG. 7.

AS SHOWN ON THE DRAWINGS

The principles of this invention are particularly useful when embodied in an apparatus 10 (FIG. 1) for registering two separate webs of wrapping material. The apparatus 10 includes a frame 12 which supports a motor 14, FIG. 3.

As can be seen best in the diagrammatic view of FIG. 2, the frame 12 supports a pair of upper and lower supply rolls 16 and 18, respectively, either or both of which supply webs of stretchable or tensionable wrapping material 20, 22, respectively, to the apparatus. The upper and lower control for braking each of the webs is identical and the subsequent description will be with respect to the upper brake system. The web of film 20 is supplied by supply roll 16 to a set of drag pinch rolls, including a drag pinch roll 26a, and a rubber roller 28a, which are geared together and to an electric drag brake 30a. The web is then pulled over a series of rollers 32a, 33a, 34a, and 35a, by a pair of jaws 62. Between the rollers 33a and 34a, the web 20 passes a suitable sensing means which may be pneumatic, fluidic, etc., but is here shown as an electric eye 36a. Corresponding reference numbers 26b and 28b through 36b have been applied to the identical elements associated with the web 22.

The electric eye scanners 36a and 36b are adjustable in line with the web travel, so that they respond in phase to printed spots passing the scanners on each web 20 and 22, respectively.

The lower web 22 passes over a series of rollers 38, 40 and 42. The web 22 engages a product 44 to be packaged at the roller position 40 where the web 22 assumes a generally horizontal travel path toward meeting with the web 20. The product 44 is supplied over an infeed conveyor 46 which at one end drives a chain 52. The chain 52 drivingly engages a sprocket gear on the roller 38 and a sprocket gear on a cam 48. The cam 48 engages and periodically operates the actuator of a cam switch 50 to indicate the position of the product 44. The cam 48 and switch 50 rotate in a one-to-one (1:1) relationship with the product 44 and the package to be produced therefrom. The switch 50 determines the amount of correction time available for the braking of each of the webs by the drag brakes 30a and 30b. This is accomplished by a web brake control 54 that receives signals from the electric eyes 36a and 36b and supplies braking signals to the drag brakes 30a and 30b. The webs 20 and 22 are joined with the product therebetween at a pair of heat sealing jaws 60 which are disposed on opposite sides of the webs 20 and 22 to provide marginal heat seals. The joined web then advances through the pulling jaws 62 for further processing by the packaging apparatus.

The electrical control circuitry for the double web registration drive and control elements includes a master feed control 100 that includes on-off switches for the power supply 102, seam sealer 104, end sealer 106, main drive motor 110, gas flush control 112, die release mechanism 114, film feed control 116 and the web brake control 54. The elements shown in block diagram form in FIG. 6 form no part of the invention with the exception of the web brake control 54 for a pair of relatively movable webs.

The web brake control 54 is shown in detail in FIG. 7. Power is supplied over a pair of input lines 140, 142 through an on-off switch 144. Connected between the power supply leads 140, 142 is an upper electric eye circuit 150 including an upper electric eye 152 which corresponds to the electric eye 36a placed in proximity to the upper web FIG. 2. The electric eye 152 is in series with a normally closed contact CR1 and a brake relay coil CR1. In parallel with the upper electric eye 152 and normally closed contact CR1 is a switch blade 154 of the one-to-one timer cam switch 50 and a normally open contact CR1. Across the supply leads 140, 142 is a series circuit including a switch 160, a normally closed contact CR3, a switch blade 162a, and a relay coil CR2. The switch blade 162a is part of a ganged switch 162.

The lower eye control 170 includes across the power supply leads 140, 142 a switch 172 in series with a normally closed contact CR2, a switch blade 162b of the ganged switch 162 and a relay CR3. In parallel with the switch 172 is a switch blade 174 of a two-to-one timer cam (not shown), a normally open contact CR3, and the lower electric eye 178 which corresponds with the electric eye 36b placed in proximity to the lower web in FIG. 2. Connected to the lower electric eye 178 is a local circuit including a normally closed contact CR1, which is the initiating contact.

The supply leads 140, 142 are connected through a voltage-dropping resistor 180 to a full-wave rectifier 182. The direct current output of the full-wave rectifier 182 is taken across a pair of direct current supply leads 184 and 186. The supply leads 184 and 186 are connected through a series of parallel potentiometers to energize the upper and lower brake solenoids.

The upper brake solenoid 190 has a pair of parallel potentiometers 192 and 194 connected between the direct current supply leads 184 and 186. The center tap 196 of the potentiometer 192 is connected to a normally closed contact CR2, and the parallel connection of the upper brake 190, a capacitor 198 and an indicator light 200 to the positive direct current supply lead 184. The center tap 204 of the potentiometer 194 is connected to a normally open contact CR2, which is connected to the parallel circuit, including the upper brake coil 190, the capacitor 198, and the indicator light 200. The center tap 196 supplies a nominal working voltage to the brake coil 190 through the normally closed contact CR2.

The lower brake coil 210 is energized through a circuit including a pair of potentiometers 212 and 214 connected to the direct current supply leads 184 and 186. The center tap 216 of the potentiometer 212 is connected through a normally closed contact CR3 to the lower brake coil 210, which is in parallel with a capacitor 218 and an indicator light 220. The center tap 224 of the potentiometer 214 is connected through a normally open contact CR3 to the parallel circuit including the lower brake 210, capacitor 218, and the indicator light 220.

In operation, the two electric eyes 152 and 178 scan the upper and lower webs as indicated by the electric eyes 36a and 36b of FIG. 2. The drag brakes 30a and 30b are set to allow the lower web 22 to have the least tension and thereby advance relative to the upper web 20.

With the switch 144 closed by the operator to energize the web brake control circuitry 54, the electric eyes 152 and 178 are energized and switch blades 154 and 174 are closed. The full-wave rectifier 182 supplies direct current across the direct current supply leads 184 and 186.

Assuming the lower web 22 is ahead, then the lower electric eye 178 will fire first, This closes a circuit from the supply lead 140 to the supply lead 142 and energizes the relay coil CR3. The normally open contact CR3 to form a holding circuit around the switch 172 and the lower electric eye 178 and energize the lower brake coil 210 through the potentiometer 214 over the higher degree of energization as set by nominal voltage provided through the potentiometer 212, the center top 216, and the normally closed contact CR3.

The relay CR3 will energize the lower web brake coil 210 to energize the lower brake 30b. This will add tension to the lower web 22 and cause the lower web to stretch and correct its position relative to the upper web 20. Normally, the correction is for less than one-sixty-fourth inch. The actuation of brake 30b and 2:1 cam-operating switch 174 prevents the upper brake 30a from being actuated for at least two cycles. The braking system is self-correcting. The lower brake 30b will hold until two bags are complete at which time the cam actuated switch blade 174 will open to reset the circuit.

When the switch blade 174 is opened by the two-to-one timer cam 48, the normally open contacts CR3 are opened and the lower brake operating coil 210 is energized at a nominal working voltage as determined by the setting of the center tap 216 in circuit with the normally closed contact CR3.

Assuming the upper web 20 is ahead, the electric eye 152 will fire and close the circuit to the relay coil CR1. The normally open contact CR1 will close and the relay coil CR1 will continue to be energized through the switchblade 154 and normally closed contact CR1 in parallel with the upper electric eye 152. The lower electric eye 178 will be deenergized by the opening of a normally closed initiating contact CR1 and no braking action will occur. The upper or lower brake coils, 190 and 210, may be manually energized by closing the switches 160 and 172, respectively.

Summarizing, the registration of each of the webs is with respect to the product 44. When one electric eye 36a or 36b, FIG. 2, indicates that one of the webs 20 or 22 has crept ahead of the other, or is out of phase with the other web, the eye that is scanning the web that is moved ahead calls for a correction to be made by the brake control 54. The correction is made by the electric brake 30a or 30b acting on the drag pinch rolls 26a or 26b. A nominal and adjustable working voltage is applied to each drag brake 30a and 30b. When an electric eye 36a or 36b calls for a correction, an additional correcting voltage is applied to the drag brake involved to apply additional tension to that web, so that it stretches and comes back into registration with the other web. This system is designed to correct tension for at least one package cycle as determined by the cam 48 and the switch 50 relative to the upper web 20 or two package cycles relative to the lower web 22.

An alternative embodiment of the web brake control 54 utilizes time delay relays, FIG. 8. The one-to-one timer cam switch blade 154 of the one-to-one timer cam-operated switch 50 is connected to the supply lead 142 and through the normally open contacts CR1' and CR2' to the upper electric eye 152 and lower electric eye 178, respectively.

In series with the upper electric eye 152 is a normally closed contact CR2' and a relay coil CR1'. In series with the lower electric eye 178 is a normally closed contact CR1' and a relay coil CR2'.

Between the supply leads 140 and 142 are a pair of time delay circuits including, respectively, a pair of normally open contacts CR1' and CR2', each of which are in series with a time delay relay TD1 and TD2, respectively.

Between the DC supply leads 184 and 186 are the potentiometers 192 and 194. The parallel circuit including the upper brake coil 190, the capacitor 198, and indicator lamp 200 are connected to the center taps 196 or 204 by a time delay contact TD1.

Similarly, the lower brake coil 210 is connected to either of the center taps 216 or 224 through a time delay switch contact TD2.

In operation, the electric eyes 152 and 178 scan the upper and lower webs 20 and 22, respectively. As in the embodiment of FIG. 7, the operator closes the switch 144 to initiate operation. This energizes the upper electric eye 152 and lower electric eye 178. The switchblade 154 is closed at this point in the operation. The rectifier 182 supplies direct current across the direct current supply lead 184 and 186.

Assuming the upper web 20 has advanced relative to the lower web 22, the upper electric eye 152 closes to complete the circuit to energize the relay coil CR1', the normally open contacts CR1' close, time delay relay coil TD1 is energized, and the upper brake coil 190 is energized through the potentiometer 194, the center tap 204, the relay contact TD1 to the direct current positive supply lead 184.

Contacts on the relay CR1' will simultaneously lock out the signal from the lower electric eye 178 and energize the coil of the time delay relay TD1.

When the switchblade 154 is opened by the one-to-one cam 48, this opens the circuit to the relay coil CR1' to deenergize the relay coil and cause the opening of the normally open contacts CR1' in series with the time delay relay coil TD1. After a predetermined time, the time delay contact TD1 opens the circuit from the center tap 204 and closes the circuit from the center tap 196 to thereby effect the nominal energization of the lower brake coil 190.

The two adjustable time delay relays contacts TD1 and TD2 delay opening after the coil TD1 and TD2 is deenergized. They are set to open some time after a bag has been completed. Therefore, if the upper web 20 remains ahead of the lower web 22, the upper brake 30a will not deenergize with each bag, but will remain energized continuously.

In this embodiment there is constant adjustment of the upper web 20 or lower web 22. This is because of the impossibility of maintaining identical tension on the webs resulting in creeping of the webs relative to each other. When the electric eye 152, for example, fires, it causes braking of the web 20 for a predetermined time. At the end of this predetermined time either electric eye may fire.

A third embodiment of the web brake control circuitry includes a lockout feature for the signal from the lower electric eye 178, FIG. 9. The center tap 196 is connected through a normally closed contact CR1' to the parallel circuit including the upper brake energizing coil 190, the capacitor 198, and the indicator light 200. The center tap 204 is connected through the normally open contact CR1' to the parallel upper brake coil circuit. The parallel circuit, including the lower brake coil 210, the capacitor 218, and the indicator lamp 220 is similarly connected to the pair of potentiometers 212 and 214 through the center taps 216 and 224 and the normally closed contact CR2' and normally open contact CR2', respectively.

As in the embodiments of FIGS. 7 and 8, closure of the switch 144, FIG. 9, causes the energization of the upper and lower electric eyes 152 and 178 respectively. The two-to-one cam switch actuated blade 174' is closed and the rectifier 182 is supplying direct current energization across the direct current supply leads 184 and 186. Assuming the upper web 20 is ahead, the upper electric eye 152 closes to cause the energization of the relay coil CR1'. A holding circuit is formed around the upper electric eye 152 by the switch blade 174' and normally opened contact CR1'. The upper brake coil 190 is energized from the potentiometer 194, center tap 204, through the normally open contact CR1.

This condition will continue until two bags are complete, at which time the two-to-one cam actuated switch blade 174' will be opened to reset the circuit and allow the two electric eyes to choose again as to which will be the first to be fired.

The webs 20 and 22 may be printed with different repeats. That is, the indicia supplied for the electric eyes 36a and 36b, FIG. 2 would be at shorter intervals with respect to one of the webs. In this system, the web with the longer repeats would be adjusted to a nominal working web tension, and the second web with the shorter repeats would be corrected by intermittent additional tension, or continuous variable tension from the electric eye system to keep it stretched and in registration with the first web.

This system is especially designed for films that are stretchable such as cellophanes, laminates of cellophanes, polypropylene laminates, polyvinyl chloride (Mylar) and other materials used for packaging.

Although minor modifications might be suggested by those versed in the art, it should be understood we wish to embody within the scope of the patent warranted hereon all such embodiments as reasonably and properly come within the scope of our contribution to the art.

Claims

We claim:

1. A method of maintaining indicia-carrying webs of film in registry comprising the steps of:

supplying webs independently from separate rolls;

passing each web through its own set of drag pinch rolls under the control of a respective brake;

normally applying a nominal working voltage to each brake;

sensing the relative positions of the indicia on the webs by individual electrical sensing systems;

actuating a timing cam in coordination with the position of a product to be packaged in the webs;

detecting relative disposition of the indicia on the webs respectively responsive to signal of the sensing systems; and

causing operation of the brake of the drag pinch rolls for the one web on which the indicia are in overrun out of register relation to the other web, comprising supplying an over voltage to the brake associated with said one web responsive to the timing cam and said electrical sensing, whereby a correcting tension is selectively applied by the drag pinch rolls to said one web.

2. A method of maintaining a pair of webs in registry comprising the steps of:

supplying the webs independently by separate rolls;

passing each web through its own set of drag pinch rolls;

gearing the individual sets of drag pinch rolls together; braking each set of drag pinch rolls;

sensing the position of the webs individually;

actuating a timing cam in coordination with the position of a product to be packaged in the webs to indicate a cycle of packaging operation;

correcting the position of the webs when any lack of registration is sensed in any web by braking the drag pinch roll for the overrunning web; and

maintaining the braking for a predetermined time after the packaging cycle.

3. A method according to claim 2, wherein the webs are selected from the group consisting of cellophanes, laminates of cellophanes, polypropylene laminates, polyester laminates, polyvinyl chloride laminates, polyethylenes, and the like.

4. Apparatus for registering corunning webs of material having means thereon which must be maintained substantially in registry with one another and with product supplied at uniform intervals therebetween comprising a means for feeding separate webs and running the webs together with the product therebetween; means for feeding product at uniform intervals between the webs; timing means synchronized with said feeding means; a respective set of drag pinch rollers through which the webs are run, each said set having selectively operable controlling brake means; and means correlated with said timing means for sensing the relative position of said means on the webs and, upon sensing relatively misalignment of said means, operating the brake means of whichever of the pinch rollers of the web that is more advanced and causing said pinch rollers to tension the more advanced web relative to the trailing web to correct the misalignment.

5. A plural web packaging machine for a product comprising:

means to supply plural webs;

means disposed in sensing relationship to each web; conveyor means for supplying the product;

cam means correlated with the position of the product relative to the webs;

brake means for each of the webs;

brake control means responsive to signals from the sensing means and the cam means to actuate the brake means for each of the webs for at least a packaging cycle to tension either of the webs whereby the webs are maintained in registry with one another and the product.

6. A packaging machine according to claim 5, wherein at least one of the webs has indicia thereon which must be in registry with a product to be packaged and at least one of the webs is tensionable and the brake means act to stretch the stretchable web relative to the other web on sensing of a misalignment by said sensing means relative to the product, to assure a package with the indicia and the product in proper registry.

7. A packaging machine according to claim 5, wherein the webs are selected from the group consisting of cellophanes, laminates of cellophanes, polypropylene laminates, polyester laminates, polyvinyl chloride laminates, polyethylenes, and the like.

8. Apparatus for registering two separate webs of wrapping material for a product to be formed into a package comprising:

supply means for each of the webs;

drag pinch roll means for each of the webs;

electric brake means for each of the drag pinch roll means;

drag brake means for each of the supply means;

electric eye means disposed in sensing relationship to each of the webs;

cam and switch means correlated with the position of the product relative to the webs;

time correction means responsive to the electric eye means and the cam and switch means whereby the electric brake means acting on the drag pinch roll means for either web is automatically selectively actuated.

9. Packaging apparatus as recited in claim 8, wherein a nominal working voltage is applied to at least one of said drag brake means for normal tensioning.

10. Packaging apparatus as recited in claim 9, wherein said brake means receive supplemental correcting voltage over the nominal working voltage from said time correction means to apply additional tension to the associated web, so that said web is tensioned and comes back into registration with the other web.

11. A packaging apparatus as recited in claim 10, where said supplemental voltage is applied for at least a packaging cycle.

12. A packaging apparatus as recited in claim 10, wherein the supplemental voltage is applied for several cycles of the packaging machine until the web has been pulled back into registration.

13. A web-packaging machine for a product comprising:

means to supply a pair of webs;

sensing means disposed in sensing relationship to each web;

conveyor means for supplying the product;

timing cam means responsive to the position of the product relative to the webs;

brake means for each of the webs; and brake control means responsive to signals from the sensing means and the cam means to actuate the brake means for each of the webs for at least a packaging cycle to tension one or both of the webs whereby the webs are maintained in registry with one another and the product.

14. A packaging machine as recited in claim 13, wherein the brake control means include a time delay relay to maintain the actuation of the brake means for a predetermined time after completion of a packaging cycle.

15. An apparatus for registering two separate webs of wrapping material for a product to be formed into a package comprising:

supply means for each of the webs;

drag pinch roll means for each of the webs;

electric brake means for each of the drag pinch roll means;

sensing means disposed in sensing relationship to said webs;

cam and switch means coordinated with the position of the product relative to the webs to determine a packaging cycle; and

relay means responsive to said sensing means to energize one of the electric brake means and lock out the signal from the other brake means for at least one packaging cycle.

16. Apparatus according to claim 15, wherein a nominal working voltage is applied to each of said brake means for normal operating tension.

17. Apparatus according to claim 16, wherein an additional correcting voltage over the nominal working voltage from said relay means is applied to the brake means associated with any web sensed by the sensing means as overrunning the other web whereby to apply additional tension to that web, so that the overrunning web is tensioned to come back into registration with said other web.

18. A packaging apparatus according to claim 15, wherein said cam is a two-to-one cam to provide energization of the brake means for at least two packaging cycles.