Abstract:
Disclosed is a rotary apparatus suitable for processing and working a web or sheet of materials such as plastic films, non-woven substrates, metal foils, paper, diaper cores and the like. Such apparatus includes counter-rotating anvil and tool rolls through which the web or sheet of material to be worked is fed. The tool roll includes at least one processing tool for working the web or sheet of material. The force of the tool on the web or sheet being worked is regulated by a force applied to the processing tool or the anvil surface of the anvil roll by a force-transmitting chamber which includes a fluid. The force applied is adjusted by altering the pressure of the fluid within the force-transmitting chamber.

Description:
FIELD OF THE INVENTION 
     This invention relates to an apparatus for processing and working continuous webs or discrete sheets of materials, including, for example, plastic films, non-woven substrates, metal foils, paper, absorbent pads, and the like. More particularly, the invention relates to a force-adjustable rotary apparatus for cutting, embossing, bonding, printing, etc., such webs or sheets of materials. 
     BACKGROUND OF THE INVENTION 
     Rotary web or sheet converting devices and setups are known, especially, for use in high speed applications for cutting, embossing, bonding and other process operations for working continuous webs or discrete sheets of materials. Such devices and setups usually involve the use of oppositely rotating rolls, one of which may carry one or more processing tools, and another roll which may serve as an anvil against which the material is worked by the processing tool. As the rolls rotate, when the tool and the anvil meet to work the web or sheet of material, the force applied between the tool and the anvil is an important factor affecting quality and efficiency of the operation. This is because the force affects the wear of the tool and, therefore, the frequency of downtime of apparatus for changing or repositioning the tool. The amount of force that the tool exerts on the web or sheet depends upon the engagement of the tool against the anvil surface. Very small differences in the engagement may result in substantial changes in the amount of the force, and this, in turn, may affect the longevity of the tool. The accuracy of the engagement may become even more important for relatively large tools when even a very small misalignment of the tool in relation to the anvil may subject a part of the tool to excessive forces, which in turn may result in accelerated wear of that part of the tool. Thus, because the amount of force between the tool and the anvil in a conventional rotary apparatus depends upon engagement of the tool against the anvil, a conventional rotary apparatus requires precise positioning of the tool in relation to the anvil. 
     Further, due to the required accuracy of the positioning of the tool, a conventional rotary apparatus generally involves substantial setup time to manually position the tool relative to the anvil. The manual setup may require a complete shutdown of the machine which, in turn, results in significant downtime and inefficiency. 
     Still further, during working of the material, as the tool gradually wears and deteriorates, the quality of the working may also deteriorate. Usually, the quality can be recaptured by increasing the force between the tool and the anvil. For conventional rotary apparatus, this means changing the engagement of the tool in relation to the anvil by repositioning the tool radially toward the anvil. Because a conventional rotary apparatus does not have the capability of changing the force during rotation, the change in force may require that the machine be shutdown, thus resulting in significant downtime. Therefore, in order to extend the time between shutdowns, the tool is usually adjusted to provide a larger than immediately needed increment of engagement. However, the drawback of this procedure is the generally reduced overall tool longevity due to more accelerated wear of the tool as the larger increments of engagement result in higher forces between the tool and the anvil. 
     Yet another drawback of a conventional rotary apparatus is that the apparatus generally requires different engagement between the tool and the anvil at lower rotational speeds than at higher rotational speeds, i.e., less clearance or more compression or interference between the tool and the anvil at lower rotational speeds than at higher rotational speeds. Because conventional rotary apparatus does not have the capability of changing the engagement of the tool during rotation of the tool, the tools are usually set for engagements suitable for lower rotational speeds to ensure satisfactory working of the material during machine startup. Working at higher rotational speeds (i.e., at production speeds after machine startup) with engagements suitable for lower rotational speeds may result in excessive forces between the tool and the anvil during higher rotational speeds. The effect may be accelerated wear of the tool at production speeds. 
     Thus, a conventional rotary apparatus exhibits a number of drawbacks which lead to operational deficiencies due to the initial setup time required, the frequency and duration of downtime necessary to maintain the proper operation, and the reduced longevity of the tool. 
     Accordingly, it may be desirable to provide a rotary apparatus which overcomes certain of the drawbacks exhibited by conventional rotary apparatus. Specifically, it may be desirable to provide a rotary apparatus which permits precise adjustment of the force between the tool and the anvil with minimal or no downtime. Further, it may be desirable to provide a rotary apparatus which employs a fluid pressure means for ready and quick adjustment of the force between the tool and the anvil with minimal or no downtime. Even further, it may be desirable to provide a rotary apparatus which enables one to reduce the time needed for changing the tool. 
     SUMMARY OF THE INVENTION 
     In order to overcome the drawbacks of current rotary apparatuses, the present invention provides a rotary apparatus suitable for processing and working a web or sheet of material such as plastic films, non-woven substrates, metal foils, paper, diaper cores and the like. Such an apparatus preferably includes a) a frame; b) an anvil roll (or similar component carrying an anvil surface) which is rotatably mounted on the frame; c) a tool roll (or similar component capable of carrying a tool) which is also rotatably mounted on the frame opposite the anvil roll; and d) drive means for rotating the anvil roll and the tool roll in opposite directions in a manner suitable for feeding the web or sheet of material being worked between the anvil roll and the tool roll. The tool roll has at least one processing tool associated with it. Such a tool is suitable for working the web or sheet of material which is positioned between the anvil roll and the tool roll. The apparatus also includes at least one chamber which includes a fluid and which is in force-transmitting communication with either the processing tool or with the anvil surface of the anvil roll or both such that a change in the fluid pressure (hydraulic or pneumatic) within the chamber serves to alter the force that is applied by the processing tool to the web or sheet of material being worked. Preferably the apparatus also includes means for changing and adjusting the pressure of the fluid within the chamber. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the present invention, it is believed that the invention will be better understood from the following figures taken in conjunction with accompanying description in which like parts are given the same reference numeral. 
     FIG. 1 is a simplified cross sectional view of a rotary apparatus embodying the essential features of this invention. 
     FIG. 1A is a magnified view of one of the radial clearances shown in FIG.  1 . 
     FIG. 2 is a simplified front view of the rotary apparatus. 
     FIG. 3 is a simplified cross sectional view of a tool roll embodying an air cylinder. 
     FIG. 4 is a simplified cross sectional view of a tool roll embodying a die cutter. 
     FIG. 5 is a simplified cross sectional view of a tool roll employing an embossing tool. 
     FIG. 6 is a simplified cross sectional view of an anvil roll employing an airbag. 
     FIG. 7 is a simplified side view of a rotary apparatus employing an airbag outside a tool roll. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     This invention relates to an apparatus for cutting, embossing, bonding, and the like, webs or sheets of materials. The apparatus of the present invention may be useful for the processing of any material which has sufficient structural integrity to be processed as a continuous web or a discreet sheet, such as plastic films, non-woven substrates, metal foils, foams, rubbers, and other materials, either separately or in a combination, in a single or multiple-layer forms. However, for the purpose of simplicity the invention will be described in terms of preferred and alternative embodiments as shown in the drawings. 
     Referring now to the drawings, FIGS. 1 and 2 illustrate one preferred embodiment of the present invention, wherein a rotary cutter  2  is used to cut a web of material  6 . The rotary cutter  2  comprises a pair of generally parallel, counter-rotating rolls  5 , both of which are mounted on a frame  13 . The counter-rotating rolls  5  may be positioned vertically, horizontally, inclined, or in any other position. One of the rolls includes a tool roll  10  and the other roll includes an anvil roll  20 . Drive means cause the tool roll  10  or anvil roll  20  to rotate in opposite directions from each other. In FIG. 1, for example, if the tool roll  10  rotates in a counterclockwise direction, then the anvil roll  20  rotates in a clockwise direction. The tool roll  10  also includes a knife assembly  24  operatively associated with an airbag  30 . 
     The tool roll  10  may include one or more knife assemblies  24 . Further, the tool roll  10  may be a circular roll or any other shaped roll, or any other mechanism or device which can be adapted to hold the knife assembly  24  or other tool in a position to work the web of material  6 , being fed between the tool roll  10  and anvil roll  20 . In a preferred embodiment, as shown in FIGS. 1 and 2, the knife assembly  24  works the web of material  6  against the anvil roll  20 . Either the tool roll  10 , the anvil roll  20  or both may be rotatably supported within the frame  13  by any means including, for example, bearings  11 . The frame  13  may be any conventional frame or any other means for holding the tool roll  10  and anvil roll  20  in a desired position. The anvil roll  20  may include one or more anvils  35  located around the periphery of the anvil roll  20  which generally correspond with the knife  25  during rotation so as to provide a desired anvil surface  36  against which the knife  25  can cut the web of material  6 . The anvil roll  20  may be a circular roll or any other shaped roll, or any other mechanism or device which may be adapted to hold the anvil  35  in position to interact with the knife  25 . Alternatively, the anvil roll itself may provide the desired anvil surface  36  against which the knife  25  can cut the web of material  6 , such that no anvil is necessary. 
     Also as shown in FIG. 1, the knife assembly  24  may include a knife  25 ; a knife-chuck  26  for nesting the knife  25  in a preferred position; and plates  27  for securing the knife  25  in position. However, the knife  25  could be held by any other means which may be adapted so as to hold the knife  25  in a position to cut the web of material  6 . In one preferred embodiment, the knife  25  may comprise a square-shaped tool having four cutting edges  25   a . However, the knife  25  may have any number of cutting edges, and the knife  25  may be of any form and size so as to provide sufficient cutting means for the web of material  6  and the like. For example, the knife  25  can be a rectangular blade having one or two cutting edges, or have a triangle or hexagonal shape, etc. Also, the knife  25  may be made from any suitable material, such as a tool steel, ceramics, composite materials, etc. In a preferred embodiment, as shown in FIG. 1, the knife assembly  24  may be joined to the airbag  30  through a spacer  28  and a mounting plate  29 . In a preferred embodiment, the mounting plate  29  may include dove-tail sides  29   a  and  29   b  for engaging with the dove-tail holders  33  and  34 . The dove-tail holders  33  and  34  are attached to the tool roll  10  and provide radial clearance  33   a  and  34   a  for the dove-tail sides  29   a  and  29   b , preferably of about 0.002″ and 0.005″, respectively. The mounting plate  29  provides not only a desired relative position of the knife assembly  24  and the airbag  30  in relation to the tool roll  10 , but also ensures that the cutting force which occurs between the knife  25  and the anvil  35  is transmitted from the airbag  30 . (As used herein, the term “cutting force” refers to the force which occurs between the knife and the anvil when material is cut.) It should be noted that any other mounting arrangement of the knife  25  and the airbag  30  may be suitable to provide a desired position of the knife  25  in relation to the tool roll  10  and a transmission of the cutting force from the knife  25  to the airbag  30 . The spacer  28  serves to provide a desired engagement or interference between the knife  25  and the anvil  35 . The spacer  28  may be machined to a desired thickness, preferably after assembling the knife assembly  24 . (As used herein, the term “interference” refers to the interference or radial compression between the knife  25  and its corresponding anvil  35  due to the overlapping rotational trajectories  17  and  18  of the knife  25  and the anvil  35 , respectively.) However, other mounting arrangements for achieving a desired relative position between the knife  25  and the anvil  35  may be suitable, for example, use of a shim stock, etc. 
     In a preferred embodiment, the airbag  30  includes an expandable vessel  31  which is enclosed from the sides by a front plate  32   a  and a back plate  32   b . The plates  32   a  and  32   b  can move generally parallel to each other upon the inflation or deflation of the vessel  31 . The airbag  30  may be of any size, shape, or form so as to provide the desired force between the knife  25  and the anvil  35 . One suitable airbag  30  is an Airstroke Actuator, Model No. W01-358-7731, available from Firestone Corp. 
     The airbag  30  may serve to adjust the cutting force between the cutting knife  25  and the anvil  35  by changing the air pressure in the air bag  30 . Accordingly, the present invention may also include means for changing or regulating the pressure within the air bag  30 . In contrast to the prior-art rotary cutters, in which the cutting force can only be adjusted by changing the interference between the knife and anvil, the rotary cutter of the present invention allows adjustment of the cutting force without changing the interference between the cutter and the anvil. The interference can be set once, for example, via the spacer  28 , to ensure a complete contact between the knife and the anvil, and the cutting force can be then changed without readjusting the knife  25  and without stopping the rotary cutter  2 . The cutting force can be changed by increasing or decreasing the air pressure in the air bag  30 . Similarly, after the rotary cutter  2  starts up and accelerates to a target production speed, the air pressure in the airbag  30  can be adjusted to any desired level. Also, the air pressure can be increased, without stopping the rotary cutter  2 , when the knife edge  25   a  becomes dull and a higher cutting force is needed to maintain the desired quality of the cut. The increase of the air pressure may be minimal, but sufficient enough to maintain the quality of the cut. After the knife edge  25   a  deteriorates further, the air pressure in the airbag  30  can be increased further, and again, incrementally enough to maintain the desired quality of the cut. 
     In a preferred embodiment, a drive means for rotating the cutter  2  is operatively associated with the tool roll  10  and the anvil roll  20  to affect predetermined synchronized counter-rotation of the rolls. It should be noted that the drive means may be operatively associated with either one of the rolls, or both. Also, the tool roll  10  and/or anvil roll  20  may be driven by the web of material  6  if the web of material  6  has sufficient integrity for rotating the rolls  10  and/or  20 . 
     It should be also noted that the number of the tool rolls  10  or the number of the anvil rolls  20  operatively associated with each other does not affect the present invention. Any number of tool rolls and any number of anvil rolls operatively associated in various combinations, can be used. 
     It should be also noted that as an alternative to the air bag  30 , any other fluid-pressure chamber containing a fluid and which is capable of changing a pressure of the contained fluid and transmitting that change in pressure into a force extending outside the device can be used as the chamber in the present invention. The chamber may comprise, for instance, pneumatic or hydraulic devices utilizing any fluid, for example, gases, oils, and other fluids, or combinations thereof As an example of an alternative embodiment, FIG. 3 illustrates the use of an air cylinder  60  positioned in the tool roll  10  in place of the airbag  30 . 
     Means for changing the pressure of the fluid in the chamber can include any known device or conventional arrangement wherein the amount of fluid in the chamber can be changed or temperature and pressure conditions within the chamber can be changed. One suitable pressure regulating device can be, for example, a hand regulator valve Model R08-200-RGMA, available from Norgren Co. 
     It should be further noted that as an alternative to the knife  25 , any other processing tool affecting the web of material  6  can be used in the present invention, For example, the tool roll  10  may employ a die cutter  70 , as shown in FIG. 4, for performing area cuts from the web of material  6 . Further, the tool roll  10  may employ an embossing tool  80 , as shown in FIG. 5, for embossing the web of material  6 . Still further, the tool roll  10  may employ a printing tool or a bonding tool, such as, for example, a heat bonding, ultra-sound bonding, etc. Even further, the tool roll  10  may employ any combination of the tool alternatives described above. 
     As an alternative to locating the air bag  30  in the tool roll  10 , the air bag  30  or any other fluid-pressure device as described above for use as the chamber may be located in the anvil roll  20  and associated with an anvil  35  to affect the force between the anvil  35  and the knife  25  or any other alternative tool as described above. FIG. 6 shows the air bag  30  which is located in an anvil roll  90  and is attached to the anvil  35 . 
     In an alternative embodiment, the air bag  30  or any other fluid-pressure device as described above for use as the chamber may be located outside the tool roll  10  and/or the anvil roll  20 . For example, FIG. 7 illustrates the airbag  30  located outside the anvil roll  10 . In this case, the anvil roll  10  is slidably positioned in a frame  95  via a slide  96  or any other means that would allow radial movement of the tool roll  10  in relation to the anvil roll  20 . This enables one to adjust the force between the tool roll  10  and the anvil roll  20  for working the web of material  6  by adjusting the air pressure of the airbag  30  without stopping the machine. 
     While particular embodiments and or individual features of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Further, it should be apparent that all combinations of such embodiments and features are possible and can result in preferred executions of the invention. Therefore, the appended claims are intended to cover all such changes and modifications that are within the scope of this invention.