DISKETTE LINERS

SPECIFICATION

Technical Field

This invention generally relates to an apparatus and method for efficiently producing a high volume of cut products, and more particularly, for producing continuous rolls of liners for use in making floppy magnetic disks.

Background Art In conventional manufacturing equipment for producing products from sheets of paper, fiber, fabric, and the like, it is highly advantageous to have a manufacturing process that is substantially continuous and automated in order to produce a high output of products at efficient speeds. A particular example is the manufacturing of liners for floppy magnetic disks. Heretofore, such liners have been produced by cutting out individual liner units from a continuous sheet of nonwoven fibrous material, as shown, for example, in U.S. Patent 4,681,004 issued to Waldner on July 21, 1987. The volume of output can be improved, as shown in U.S. Patent 4,773,293 issued to izuta et al. on September 27, 1988, by cutting the liner units through two sheets stacked on top of each other. The separated liner units are then assembled with other required components into floppy disks. However, it is found that the above-described conventional production of liners and assembly of floppy disks has the disadvantage that the separated liner units require complex handling once they are cut from the sheet so that the speed and efficiency of production of the liners is limited by the requirements of the downstream assembly of floppy disks. It has therefore been desired to have the liners produced in continuous roll form, so that they can be supplied as inputs to separate assembly lines for the floppy disks. The

production of cut products in continuous roll form entails the technical problems of obtaining complete incremental cuts of the products in a strip, supporting the strip of cut products so that it does not tear during processing, ensuring that the product units can be separated accurately later despite errors in cutting or processing, and winding up the strip of cut products in a continuous roll without distortion, creasing or tearing.

Disclosure of Invention

An apparatus of the invention for manu acturing cut¬ out products in continuous roll form, comprises: a first input roll feed for supplying a continuous web of material from which the products are to be made; a second input roll feed for supplying a transport web for supporting the continuous web of product material thereon in parallel therewith along a machine directic-n; an input pair of feed rollers for incrementally advancing the two webs together to a cutting station;- he cutting station having a die cutter for cutting through he product and transport webs to form cut product units in successive increments and respective connecting portions between increments for keeping the products units joined together in a continuous strip; scrap removal means for separating the transport web and cuttings from the strip of cut products; a finished-product guide for transporting the strip αf cut products, to a windup station; and the windup station having a spool on which the cut product strip is wound as an output product roll.

In the preferred form of the invention, the product web and transport web are unwound from the roll feed under constant tension, and dancer bars are provided to provide take-up lengths for the webs to accomodate the incremental advancing of the webs to the cutting station. A plastic film unwinding sheet is wound with the continuous strip of cut products to facilitate unwinding of the product roll without tearing. An optical-servo web guide system maintains center- line tracking of the webs. The input webs can have a width which is a multiple of the width of the product units so that

multiple strips of products can be cut simultaneously therefrom. The multiple output strips are separated and wound at separate winding stations. For the particular application of the invention to floppy disk liners, the production line includes static eliminators and an ionized air blower.

Another aspect of the invention comprises the continuous strip having connecting portions provided with indented cutouts formed on respective lateral edges of the connecting portions in a direction transverse to the machine direction. The die cutter of the cutting station includes a trailing blade portion which overcuts the indented cutouts in one cut direction, and a leading blade portion which overcuts the indented cutouts in another cut direction intersecting that of a preceding cut of the trailing blade portion, in order to complete cuts despite slight variations in registration. The invention encompasses the methods for forming continuous roll product related to the above-described apparatus.

Other objects, features, and advantages of the present invention are explained in the following detailed description of the best mode of carrying out the invention, considered with reference to the accompanying drawings.

Brief Description of Drawings Figure 1 is a schematic diagram on a preferred embodiment of a continuous roll product production line in accordance with the principles of the invention.

Figure 2A is a schematic diagram of an incremental cut performed by a die cutter at the cutting station of the production line of Figure 1, and Figure 2B shows a successive cut performed so as to overlap slightly with the previous cut.

Figure 3 shows a detail of the intersection of the previous and successive cuts of Figures 2A and 2B which allows for slight variation in registration of the cuts.

Best Mode for Carrying Out the Invention

The invention is applicable generally to an apparatus and related method for manufacturing cut-out

products from a continuous web in continuous roll form, and specifically to the manufacture of continuous roll liners for use in making floppy magnetic disks. Decribed herein is a preferred embodiment of the invention as applied to the manufacture of continuous roll liners in which a wide input sheet is used to form a plurality of liner output rolls in tandem. The principles of the invention can be applied equally as well to other applications in which discrete product units are cut from a continuous web and wound up as one or more output product roll(s) for use in further manufacturing or assembly processes.

Referring to Figure 1, an apparatus for producing continuous roll liner includes a first input roll feed 10 for supplying a continuous web of non-woven product material, a second input roll feed 11 for supplying a transport web for supporting the product web, a first dancer bar 12 for the product web, a second dancer bar 13 for the transport web, a web guide system 14 for the product web, a web guide 15 for the transport web, a pair of input feed rollers 16 for incrementally advancing the two webs together, a cutting station 17 having a die cutter, a pair of output feed rollers 18, a scrap'rewind 19a for removing the transport web scrap, a scrap remover 19b for removing the edge cuttings and other scrap, and output windup spools 20a, 20b, and 20c. In the example of continuous roll liner production, the product web is an 11.875 inch wide web of non-woven fabric suitable _; for the liner material. The liner web is unwound under substantially constant tension, e.g. about 300 grams, provided by the dancer bar 12. The dancer bar uses a take-up length bf liner web to accomodate the incremental advances of the liner web to the cutting station 17 in order to avoid having to stop and start the liner input roll feed 10.

_ The liner web is guided to the input feed rollers 16 by means of an optical-servo guide system using a guide sensor 14a for center-line tracking. An ionizing statis eliminator 22 and a cold-stream humidifier 23 conditions the non-woven fabric. eb before it enters the nip of the input feed rollers 16 to aid in downstream scrap removal, as is known in the

industry .

Concurrently, 50 lb. kraft paper, also 11.875 inch wide, is unwound under constant tension, e.g. 450 grams, by means of the dancer bar 13. The paper acts as a transport medium which minimizes wrinkling and facilitates the die cutting process by insuring complete penetration through the fabric. The paper is edge guided into the input feed rollers 16 by a convex surface web guide having a radius of curvature selectedto maintain web rigidity and prevent web climbing on the guide.

The liner and kraft paper webs ^" are brought together in parallel at the input feed rollers 16 and fed therethrough along a machine direction. Pneumatic loading can be used to provide the requisite force to insure proper traction. The input feed rollers 16 are electronically indexed to advance the webs by an incremental amount. In the case of liners units having a length in the machine direction of 3.425 inches, an index length of two full pitches, i.e. 6.850 inches is nominally selected. The input feed rollers are driven by high resolution stepper motors controlled and adjusted through a computer unit.

In this example, the liner and kraft paper have a width selected to accomodate the cutting of three separate strips of liner units side by side. Each strip consists of a series of liner units in the machine direction. The liner units each have the shape, as shown in Figures 2A and 2B, of a circular disk 31 with a central hole 31 and connecting portions 32a, 32b on each side in the machine direction. The boundary between adjacent liner units is marked by a pair of indented cutouts 33, 34 on each lateral edge of the adjacent connecting portions in a cross direction transverse to the machine direction. During subsequent floppy disk assembly, each liner unit is separated from the strip along a transverse cut marked by the indented cutouts. With each incremental advance of the two webs by the index length, the die cutter at cutting station 17 is pressed down to cut through the liner and kraft paper webs against a hardened steel anvil. The die cutter is preferably a 20 ton

press and has a steel rule die 17b with three sets of blades, having a blade outline for each strip as shown in Fig. 2A, and six cavities, (three strips with two liner units each) for cutting the central holes 31. A scrap manifold 17a is housed in the_reciprocating head of the cutter for removal of the circular scrap which is blown upwards through the head by air nozzles located in the anvil. The scraps are evacuated out through vacuum ducting. Air to the anvil nozzles is supplied by the air nozzle assembly 24 indicated in Figure 1. The head travel is limited by internal stops that determine the depth of the head Movement. The head is then returned up to allow the next index length of the webs to be advanced.

Du_?ing the cutting process, slight variations in the guiding of t_te w_bs to the cutting station and registration of the webs with the cutting head may occur. Such variations can result in a slight offset from one incremental strike of the cutter blades to the next. In order to ensure that the cut¬ out -liner strips' are completely severed from the liner web from one cutter strike to the next, the invention provides for the indented cutouts to be located at the boundary between successive cuts, and a leading and trailing blade configuration which has a predetermined amount of overcutting to accomodate anticipated variations of up to .030 inch. As shown more clearly in Figures 2B and 3, the cut at the corner of the indented coutout by a trailing blade portion on a previous strike overlappingly intersects the cut of a leading blade portion on a successive strike, e.g. by about .035 inch in the machine direction and .031 inch in the corss direction. Thus, a complete cut of the corners of the indented cutouts will be made despite variations of up to .030 inch in either direction.

After each indexed cut, the output feed rollers 18 draw the three cut product strips out of the die in synchronization with advancing of the webs by the input feed rollers 16. A" differential index can be provided between input and output rollers to control the tension on the cut product strip.; by ^' computer control.

The three liner product strips are separated from

the kraft paper web by the scrap rewind 19a applying a constant torque. The kraft paper cannot be reused, and is either scrapped or sold as salvage. The liner scrap (edge trims) is evacuated through the scrap removal plenum 19b and ducted to a central scrap location. The remaining liner strips are then indexed by way of the finished product feed rollers 25 which are operated in synchronization with the input and output feed rollers. The product is anti-static treated by the ionized air blower 26 and static eliminator 27. Adhesive tape can be spliced onto the liner units if desired by a splicing table (indicated by numeral 28) .

The finished product strips are then separated and wound on respective spools 20a, 20b, 20c. In order to allow continuous winding on the spools, the strips are run under constant tension by respective dancer rolls 29a, 29b, 29c. The rewinding speed of the spools can be electronically varied depending on the height of the dancer bars. This arrangement provides uniform tensioning through the spools, thereby eliminating dimensional distortions due to stretching and product creases from internal buckling. The strips may be interleaved with polyethylene films dispensed under uniform tension from rolls 21a, 21b, 21c along with the liner strips. The interleaved films are provided to facilitate and prevent tearing of the strips during unwinding. A typical die press station can be operated at the rate of about 60 strokes per minute. With six product units (three strips with two pitches each) cut per stroke, 360 units can be formed per minute. For a typical non-woven fabric roll of the 11.875 inch width, three spools of continuous roll liners are formed each containing about 9000 liner units.

Industrial Applicability

From the foregoing description, it will be recognized by those skilled in the art that the present invention is capable of use in industry to provide a continuous roll of product units, or multiple rolls in tandem, cut from a continuous sheet or web. The invention ensures that the cut product strips are not distorted or torn and have

complete cuts formed at their incrementally indexed boundaries-. The use of the variable control dancer loops ensures uniform tensioning and improved tracking. The synchronized input, output, and finished product feed roller system-, allows the webs and output strips to be indexed smoothly, and continuously through direct nip rollers controlled with programmable acceleration, duration, and deceleration profiles. This system is not influenced by web texture or slippage. The cut product strips are wound continuously through variable speed rewind controlled by dancer loops, thereby ensuring a uniform tensioning.

Numerous modifications and variations are of course possible given the above disclosure of the principles and mode of carrying out the invention. It is intended that all such modifications and variations be considered as within the spirit and scope of the invention, as defined in the following claims..