US3752024A

US3752024A - Cutting mechanism for rotary knife cutting machines

Info

Publication number: US3752024A
Application number: US00237431A
Authority: US
Inventors: D Judelson
Original assignee: JUDELSHON Inc OSCAR I
Current assignee: JUDELSHON Inc OSCAR I; OSCAR I JUDELSHON INC US
Priority date: 1960-08-22
Filing date: 1962-11-06
Publication date: 1973-08-14
Anticipated expiration: 1990-08-14

Abstract

The present invention relates to rotary knife cutting machines which sever a roll of material wound on a core into plural narrower rolls by utilizing two rotary knives that are opposed to each other on opposite sides of the work-piece axis and by having knife feeding means that advances one of the knives into the workpiece by a fixed merement ahead of the other knife all during the working cut.

Description

United States Patent [191 Judelson CUTTING MECHANISM FOR ROTY KNIFE CUTTING MACHINES [75] Inventor: David N. Judelson, New York. NY.

[73] Assignee: Oscar I. .ludelshon Inc., New York,

221 Filedz Nov.6,1962

21 App1.No.:237,431

[62] Continuation of Ser. No. sosrT/iu tnj 'l'ci'i ai.

[52] US. Cl. 82/86 R, 82/53 R [51] Int. Cl B23b 3/04, B23b 5/14, 1323b 37/00 [58] Field of Search 82/46, 86, 101

[56] References Cited UNITED STATES PATENTS 2,457,310 Judelson 80/86 Aug. 1, 1973 2,015,877 10/1935 Thompson 82/46 X 1,098,167 5/1914 Potten 82/98 X 1,372,127 3/1921 Faunce 82/92 Primary Examiner-Harrison L. l-linson Attorney-Amster and Rothstein [5 7] ABSTRACT The present invention relates to rotary knife cutting machines which sever a roll of material wound on a core into plural narrower rolls by utilizing two rotary knives that are opposed to each other on opposite sides of the work-piece axis and by having knife feeding means that advances one of the' knives into the workpiece by a fixed merement ahead of the other knife all during the working cut.

9 Claims, 3 Drawing Figures Patented Aug. 14, 1973 3,752,024

mmvroa DAVID M Juousow 9/ F IG. 2

Afro/avers CUTTING MECHANISM FOR ROTARY ENTEE CUTTING MACHINES This is a continuation of U.S. Pat. application Ser. No. 50,917 filed on Aug. 22, 1960 Pat. No. 3,700,402 and entitled Cutting Mechanism for Rotary Knife Cutting Machines."

The present invention relates generally to rotary knife cutting machines which are adapted to sever a roll of material wound on a core into plural strips, and in particular to mechanisms for cutting relatively dense rolls of material, such as relatively thin polyethylene and like thin films of plastic, which when wound into a roll exhibits a high order of hardness.

In a typical rotary knife cutting machine, such as disclosed in U.S. Pat. No. 2,457,310 of Dec. 28, 1948 and in pending application Ser. No. 722,301 filed Mar. l8, 1958, both said patent and application being assigned to the assignee of the present invention, there is disclosed a rotary knife cutting machine which enables the automatic or manual cutting of a roll of material into a number of strips of a prescribed width. A typical machine includes a frame upon which is supported a stationary shaft which receives the roll of material wound on a core and usually enclosed within a paper wrap.

-The roll of material is rotated about the longitudinal shaft axis by means of a chuck which engages one end of the roll and is driven from an appropriate variable high speed drive. A high speed rotary knife is mounted on a knife carrier and is movable toward and away from the stationary supporting shaft. The carrier in turn is mounted on the movable carriage which has an indexing mechanism selectively engageable with the frame of the machine such that the carriage may be moved stepwise through a prescribed and adjustable traversing stroke for moving the carrier and the rotary knife into successive indexed cutting positions along the length of the machine toward the chucked end of the roll of material. After each stepwise advance of the carriage, the knife carrier is actuated, either automatically or manually, to move the rotary knife inwardly toward the stathrough the roll of material and its core to sever the same into tapes or ribbons.

Such rotary knife cutting machines maybe employed to cut relative dense rolls of material, such as of thin polyethylene film and the like, by employing a twostage operation. After a roll is placed upon the stationary shaft and turned at the prescribed speed, the first stage involves employing a rotary sawing blade to cut through the material and through the core. Rolls cut with such sawing blade have successive end cut faces defining opposite sides of the strips or ribbons, which are rough and irregular. Often, unless caution is exercised, there is a tendency for such rough end faces of the strips or ribbons to fuse due to the heat developed incident to the action of the sawing blade as it penetrates radially inwardly through the roll towards the core in its cutting stroke. After this initial rough cutting or sawing, the second stage involves the taking of a trim cut with a trimming blade to provide relatively smooth cut end faces defining opposite sides of the strips or ribbons. Here again care must be taken to rotate the trimming knife and to penetrate at a rate such as to avoid the tendency to fuse the cut end faces of the roll. Necessarily such two-stage operation is time-consuming, comparatively expensive, and wasteful of material.

It has been suggested that the two stages may be achieved concurrently in a rotary knife cutting machine by arranging the sawing and trimming knives or blades at approximately l8(Y circumferentially of the roll of material such that the sawing and trimming may occur simultaneously. One suggested system involves the mounting of the trimming knife or blade which includes two bevelled trimming edges having a pneumatic control and to similarly mount the sawing knife or blade on an independently pivoted arm with an independent pneumatic control. The sawing blade is arranged radially outwardly in relation to the trimming blade and the blades advance simultaneously through the cutting stroke toward the core such that the sawing blade lags throughout the cutting stroke. As the trimming blade moves forwardly and penetrates the roll of material, a reaction force is developed by the roll of material; and periodically the trimming blade will tend to stop in its forward motion due to such reaction force.

Concurrently, the lagging sawing blade cuts away the material removed initially by the trimming blade; and once the accumulation of cut material is removed, the operation may go. forwardly with the trimming blade making a further forward penetration into the roll of material. This proposed system is inherently fraught with difficulty since it requires for its operation the development of a reaction force or back pressure on the trimming blade which reaction force or back pressure causes the development of heat with the attendant risk of fusing the cut edges of the plastic material. Further,

it is difficult to establish optimum cutting conditions with any degree of flexibility as is required to handle various types of plastic materials and rolls of varying density and diameter.

Broadly, it is an object of the present invention to provide an improved cutting mechanism which obvi ates one or more of the aforesaid difficulties. Specifically, it is within the contemplation of the present invention to provide a cutting system for relatively dense rolls of plastic and like materials in which sawing and trimming operations occur simultaneously, with the trim taken from the roll by the trimming blade being thrown into the cut made by the sawing blade such that the trimmed material is comminutedand the cut is kept relatively free of clogging.

It is a further object of the present invention to establish individual speeds of rotation for the sawing and trimming knives or blades such as to permit the establishment of optimum cutting conditions for varying types of materials, roll densities and roll diameters.

In accordance with an illustrative embodiment demonstrating objects and features of the present inven- I tion, there is provided a cutting mechanism for cutting a roll of material into a plurality of tapes which comprises a supporting frame, a rotary sawing blade or knife having a sawing edge, and a rotary trimming blade or knife having a trimming edge. The blades are disposed substantially in a common cutting plane at right angles to the longitudinal axis of the roll of mate rial and its supporting shaft. Carrier means mount the blades on the supported frame for movement through a cutting stroke in the common cutting plane from a retracted position spaced from the longitudinal axis of 'the roll of material to an advanced position contiguous thereto. The sawing edge is disposed radially inwardly of the trimming edge by a fixed increment such that the sawing edge leads the trimming edge as the roll of material is cut. Provision is made for turning the blades at desired sawing and trimming speeds which advantageously may be made independent of each other, with the sawing blade preferably being turned at a lower rate of speed to develop a relatively low order of heat incident to the initial rough cutting action. As the sawing proceeds, the trimmed material taken from the opposite rough cut faces of the saw cut are thrown into such saw cut wherein the trimmed material is comminuted thereby keeping the cut relatively free of clogging and permitting the uniform advance of the blades through the forward cutting stroke.

The above brief description, as well as other objects and features and advantages of the present invention will be more fully appreciated by reference to thefollowing detailed description of a presently preferred, but nonetheless illustrative embodiment according to the present invention, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a fragmentary plan view of a typical rotary knife cutting machine embodying cutting mechanisms in accordance with the present invention;

FIG. 2 is a sectional view taken substantially along the line 2-2 of FIG. 1 in the direction of the arrows, and on a somewhat large scale, showing details of the cutting mechanism; and,

FIG. 3 is a sectional view taken substantially along the line 33 of FIG. 2 in the direction of the arrows, with parts broken away to show the concurrent sawing and trimming action achieved in accordance with the present invention.

Referring now specifically to the drawings, abrief description will be set forth of portions of a typical rotary knife cutting machine, generally designated by the reference numeral 10, to illustrate the environment for a cutting mechanism in accordance with the present invention. For further details of a manual machine suitable for the practice of the present invention, reference may be made to US. Pat. No. 2,457,310; and for details of an automatic machine, reference may be made to said pending US. Pat. application, Ser. No. 722,301. The machine includes a frame or support having an upright standard 12 at one end thereof from which projects the longitudinally extending stationary supporting shaft 14 which has a flat 14a on one side and which receives the roll of material R wound on a core C, as of cardboard, (see FIG. 2). The roll R is adapted to be cut into plural strips or ribbons S on a manual or automatic basis. One end of the roll of material R is brought into abutment with a chuck 16 which is of the type including a number of roll-penetrating elements which may be engaged into the outer periphery of the roll R for fixing the same, with one end thereof against the adjacent end face of the chuck plate 20. For a detailed description of an improved chuck 16 which may be employed in the present machine, reference may be made to U.S. Pat. No. 2,938,733 of May 31, 1960, assigned to the assignee herein. As seen in FIG. 1, the chuck I6 is rotated about the stationary roll-supporting shaft 14 at the prescribed roll turning speed by a variable speed drive motor 22 which is mounted on an appropriate support provided by the machine frame. The drive shaft 220 of the motor 22 is coupled to the chuck 16 by a belt and pulley coupling, including the pulley 24 on the motor shaft 220, the pulley 26 on the chuck 16 and the belt 28 trained over the

pulleys

24, 26. The belt and pulley coupling is arranged to achieve the required speed reduction between the motor shaft 22a and the chuck 16.

Mounted on the machine frame is the improved cutter assembly of the present invention, generally designated by the reference numeral 30, which includes a knife carriage or mount 32 which is movable along the machine frame in a path parallel to the longitudinal axis of the roll-supporting shaft 14 and on

appropriate guide rail

34, 36 extending through the

bearings

38, 40, 42 and 44 on the knife carriage 32. The knife carriage 32 is moved longitudinally of the machine frame through successive longitudinal traversing incuments or strokes to bring the high speed rotary sawing and trimming knives into successive positions incutting planes at right angles to the roll-supporting shaft 14, either manually or automatically, as described in US. Pat. No. 2,457,310 and said copending application Ser. No. 722,301.

Disposed within a common cutting plane and extending at right angles to the roll-supporting shaft 14, which cutting plane may be progressively advanced along the length of the roll R, are a rotary sawing blade or knife 46 and a rotary trimming blade or knife 48. As seen best in FIG. 2, the sawing knife 46 is below the roll R and the trimming knife 48 is above the roll R. The respective knives are circumferentially spaced at approximately relative to each other. The sawing knife 46 is provided with circumferential or peripheral sawing teeth 50 of an appropriate configuration to take a relatively rough sawing cut SC through the roll of material, as shown in FIG. 3; while the trimming blade 48 is provided with a V-shaped circumferential or peripheral notch 52 defining bevelled trimming edges 52a, 52b, which meet at an apex 54 inwardly of the outer periphery of the knife 48. As best seen in the enlarged showing of FIG. 3, the trimming knife 48 is of a greater width than the sawing knife 46, with median lines through the

knives

46, 48 being arranged symmetrically about a common plane and with the

outer faces

48a, 48b, of the trimming knife 48 being respectively disposed outwardly of the adjacent outer faced 46a, 46b of the sawing knife 46 for making a wider trimming cut TC. The sawing edge 50- of the sawing knife or blade 46 is disposed radially inwardly of the bevelled trimming surfaces 52a, 52b of the trimming knife 48 such that as the

knives

46, 48, concurrently penetrate the roll of material R with a fixed interval or increment therebetween, the leading sawing knife {36 makes the narrow sawing cut or groove SC which is followed up by the somewhat wider and symmetrical disposed trimming cut TC. With this arrangement, there is substantially no tendency for the sawing cut SC to clog up due to the accumulation of sawings from the roll R in that such accumulation is chewed up or comminuted by the action of the trimming knife 48.

In order to mount the rotary sawing and trimming

knifes

46, 48 on the knife carriage 32, there is provided a pair of upstanding mounting

plates

58, 60 which extend at right angles to the guide rails 34, 36 And are welded or otherwise secured to the knife carriage 32. Extending transversely of the

upstanding mounting plates

58, 60 are lower and upper mounting

studs

62, 64 which are joumaled in the mounting

plates

58, 60 and provide respective pivotal mounts for the sawing knife carrier 66 and the trimming knife carrier 68. Since the

knife carriers

66, 68 are disposed one above the other in a common vertical cutting plane, the trimming knife carrier 68 is only visable when the machine is view from above as shown in FIG. 1. The sawing knife carrier 66 includes a mounting bearing 70 on the end thereof remote from the sawing knife 46 which bearing 70 is journaled about the axis provided by the lower mounting stud 62. At its end remote from the mounting bearing 70, the knife carrier 66 is provided with a knife-supporting bearing 72 (see the dotted line shown in FIG. 2) through which extends the sawing knife shaft 74 'which is fixed at one end to the sawing knife 46 and is driven from its other end, as will subsequently be described. In a similar fashion the trimming knife carrier 68 is provided with a mounting bearing 76 at the end thereof remote from the trimming knife 68 which mounting bearing 76 is journaled on the upper mounting stud 64. At its end remote from the mounting bearing 76, the trimming knife carrier 68 is provided with a knife-supporting bearing 78 (seen in FIG. 1) through which extends the trimming knife shaft 80 which is fixed at one end to the trimming knife 48 and is driven from its opposite end, as will subsequently be described.

The sawing and trimming

knives

46, 48 are moved through their forward or cutting stroke in the cutting cycle of the machine and in the required radial rela-' tionship by the provision of a driven gear sector 82 on the sawing knife carrier 66 which is in meshing engagement with a follower gear sector 84 on the trimming knife carrier 68. By appropriate initial positioning of the

knives

46, 48 and selection of the intermeshing relationship between driven gear sector 82 and the follower gear sector 84, it is possible to arrange the sawing knife 46 to lead the trimming knife 48 by a prescribed fixed increment over the entire operative portion or stroke in the cutting cycle. In this illustrative arrangement, the driven gear sector 82 is turned to bring about the in unison advance of the

knives

46, 48 by a manual arrangement which includes a driving gear 86 which is journaled on a gear stud 88 extending between the upstanding mounting plates 56, 58, which driving gear 86 is turned by an actuating shaft 90 through a hand wheel 92. Although a manual arrangement is shown for moving the

knives

46, 48 through the cutting stroke, it will be appreciated that it is within the contemplation of the invention to actuate the

knives

46, 48 by other appropriate manual arrangements, as well as by the automatic mechanism disclosed in said copending US. Pat. application, Ser. No.722,301.

Independent drives are provided for the respective sawing and trimming

knives

46, 48 such that desired knife speeds may be established in accordance withthe type of material being cut. The trimming knife drive includes a variable speed drive motor 94 which is mounted on the knife carriage 32. A belt and pulley coupling is arranged between the motor shaft 94a and the knife shaft 80. Specifically, the upper mounting stud 64 is projected outwardly of the mounting plate 60 to serve as a pulley shaft on which there is fixed an intermediate driven pulley 96. The driven pulley 96 is coupled to a drive pulley 98 on the motor shaft 94a by a belt 100. The driven pulley 96 in turn is fixed to a further intermediate pulley 102 which is coupled by a belt 104 to a knife pulley 106 fixed to the knife shaft 80. In a similar fashion an independent drive is provided for the sawing knife 46 which includes a drive motor 108 having its motor shaft 108a coupled by driving pulley 110 and a belt 112 to an intermediate pulley 114 on the lower mounting stud 62 which serves as a pulley shaft. The intermediate pulley 114 is connected to a further intermediate pulley 116 which in turn is connected by a belt 118 to a knife pulley 120 fixed to the knife shaft 74 (see FIG. 4).

In order to facilitate a more thorough understanding of the present invention, reference will now be made to a typical sequence of cutting in accordance with the present invention:

After the machine operator places the roll of material R on the machine and engages the same with the chuck 16, the machine is placed in operation. The knife carriage 32 is indexed to the'appropriate position longitudinally of the machine to orient the coplanar sawing and trimming

knives

46, 48 to take a cut transversely through the roll R towards the core C thereof. Such indexing may be in accordance with the principles of issued patents assigned to the assignee of the present invention or in accordance with the teachings of said copending U.S. Pat. application Ser. No. 722,301. Thereupon the sawing and trimming

knives

46, 48 are moved inwardly through their cutting strokes, with the sawing edge Slll of the sawing knife 46 leading the bevelled surfaces 52a, 52b of the trimming edge 52 of the trimming knife 48. The cutting progresses until such as the sawing edge penetrates through the core C and approaches the flat 14a on the roll-supporting shaft 14. It will be appreciated that only one flat is required on the roll-supporting shaft 14 opposite the point of penetration of the sawing knife 46 in that the lagging relationship of the trimming knife 48 precludes the possibility of contact with the shaft. During the cutting operation, which progresses at a substantially uniform rate as established by the motion-imparted to the

carriers

66, 68, the sawing knife 46 takes the rough cut SC, followed by the fine cut TC of the trimming knife 48, with clogging being effectively precluded due to the comminuting action of the trimming knife 48. At the end of the cut, the

knives

46, 48 are retracted to a clearance position relative to the roll, the knife carriage is indexed, and the operation .is repeated.

A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accord- I ingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with;the spirit and scope of the invention herein.

What I claim is:

1. A cutting mechanism for cutting a roll of material into plural tapes comprising a support, a rotary sawing blade having a sawing edge, a rotary trimming blade having a trimming edge, said blades being disposed substantially in a common plane at right angles to the longitudinal axis of said roll and substantially in opposed relation to each other, carrier means mounting said blades on said support for movement through a cutting stroke in said common plane from a retracted position spaced from said longitudinal axis to an advanced position contiguous thereto, said sawing edge being disposed radially inwardly of said trimming edge by a fixed increment such that said roll of material is first cut by said sawing blade and then trimmed by said trimming blade during said cutting stroke, and means operatively connected to said sawing blade and to said trimming blade for rotating said blades.

2. A cutting mechanism according to claim 1 wherein said trimming blade is of a greater width than said sawing blade.

3. A cutting mechanism for a cutting machine including a support, a shaft on said support adapted to receive a roll of material and a chuck for rotating said roll of material comprising a rotary sawing blade having a sawing edge, a rotary trimming blade having a trimming edge, said blades being disposed substantially in a common cutting plane at right angles to the longitudinal axis of said stationary shaft and substantially in opposed relation to each other, carrier means mounting said blades on said support for movement through a cutting stroke in said common cutting plane from a retracted position spaced from said stationary shaft to an advanced position contiguous to said shaft, said sawing edge being disposed radially inwardly of said trimming edge such that said roll of material is first cut by said sawing blade and then trimmed by said trimming blade during said cutting stroke, saw-rotating means operatively connected to said sawing blade, and trim-rotating means operatively connected to said trimming blade.

4. in a cutting machine, a support, a stationary shaft on said support adapted to receive a roll of material, a chuck for rotating said roll of material, and cutting mechanisms for cutting said roll of material into plural tapes, the improvement comprising said cutting mechanisms-including a rotary sawing blade having a sawing edge, a rotary trimming blade having a trimming edge, said blades being disposed substantially in a common cutting plane at right angles to the axis of said stationary shaft and substantially in opposed relation to each other, carrier means mounting said blades on said support for movement through a cutting stroke in said common cutting plane from a retracted position spaced from said stationary shaft to an advanced position contiguous to said shaft, said sawing edge being disposed radially inwardly of said trimming edge by a fixed increment such that said roll of material is first cut by said sawing blade and then trimmed by said trimming blade during said cutting stroke, and means operatively connected to said sawing blade and to said trimming blade for rotating said blades.

5. In a rotary knife cutting machine, a frame including a knife mount, roll-supporting and turning means on said frame including a shaft adapted to receive and support a roll of material which is to be cut into a plurality of tapes while turning about the shaft axis, a sawing knife carrier mounted on said knife mount for movement toward and away from said shaft, a rotary sawing knife having a sawing edge mounted on said sawing knife carrier for rotation about a sawing axis parallel to said shaft axis, a trimming knife carrier mounted on said knife mount for movement toward and away from said shaft, a rotary trimming knife having a trimming edge mounted on said trimming knife carrier for rotation about a trimming axis parallel to said shaft axis, said sawing and trimming knives being disposed in opposed relation to each other and in a common cutting plane extending at right angles to said shaft axis, said sawing edge being disposed radially inwardly of said trimming edge by a fixed increment such that said roll of material is first cut by said sawing knife and then trimmed by said trimming knife during movement of said knives toward said shaft, means operatively connected to said sawing and trimming knife carriers for moving said sawing and trimming knives toward said shaft during a cutting stroke while maintaining said fixed increment between said sawing and trimming edges, and means operatively connected to said knives for rotating said knives.

6. In a rotary knife cutting machine according to claim 5, said trimming knife being of a greater width than said sawing knife such as to trim adjacent faces of said roll of material after cutting said said sawing knife.

7. In a rotary knife cutting machine, a frame, rollsupporting and turning means on said frame including a stationary shaft adapted to receive and support a roll of material which is to be cut into a plurality of tapes while turning about the shaft axis, a knife carriage, means mounting said knife carriage on said frame for longitudinal traverse along a path parallel to said shaft axis, a sawing knife carrier mounted on said knife carriage for movement toward and away from said stationary shaft, a rotary sawing knife having a sawing edge mounted on said sawing knife carrier for rotation about a sawing axis parallel to said shaft axis, a trimming knife carrier mounted on said knife carriage for movement toward and away from said stationary shaft, a rotary trimming knife having a trimming edge mounted on said trimming knife carrier for rotation about a trimming axis parallel to said shaft axis, said sawing and trimming knives being disposed in a common cutting plane extending at right angles to said shaft axis, said sawing edge being disposed radially inwardly of said trimming edge such that said roll of material is first cut by said sawing knife and then trimmed by said trimming knife during movement of said knives toward said stationary shaft, means operatively connected to said sawing and trimming knife carrier for moving said sawing and trimming knives toward and away from said stationary shaft during a cutting cycle while maintaining the radial relationship between said sawing and trimming edges, means operatively connected to said sawing knife for rotating said knife at a sawing speed, and separate means operatively connected to said trimming knife for rotating said trimming knife at a trimming speed.

8. A cutting mechanism for use in a rotary knife cutting machine including a frame, roll-supporting and turning means on said frame including a stationary shaft adapted to receive and support a roll of material which is to be cut into a plurality of tapes while turning about the shaft axis, a knife carriage and means mounting said knife carriage on said frame for longitudinal traverse along a path parallel to said shaft axis, said cutting mechanism including a sawing knife carrier adapted to be pivotally mounted on said knife carriage for movement toward and away from said stationary shaft, a rotary sawing knife having a sawing edge rotatably mounted on said sawing knife carrier for rotation about a sawing axis parallel to said shaft axis, a trimming knife carrier adapted to be pivotally mounted on said knife carriage for movement toward and away from said stationary shaft, a rotary trimming knife having a trimming edge rotatably mounted on said trimming knife carrier for rotation about a trimming axis parallel to said shaft axis, said sawing and trimming knives being disposed in opposed relation to each other in a substantially common plane extending at right angles to said shaft axis, said sawing edge being disposed radially inwardly of said trimming edge by a fixed increment and being of a lesser width then said trimming edge such that said roll of material is first cut by said blades on said support for movement through a cutting stroke in said common plane from a retracted position spaced from said longitudinal axis to an advanced position contiguous thereto, said sawing edge being disposed radially inwardly of said trimming edge by a fixed increment such that said roll of material is first cut by said sawing blade and then trimmed by said trimming blade during said cutting stroke, and power means for driving one of said blades.

l 8 IF i

Claims

4. In a cutting machine, a support, a stationary shaft on said support adapted to receive a roll of material, a chuck for rotating said roll of material, and cutting mechanisms for cutting said roll of material into plural tapes, the improvement comprising said cutting mechanisms including a rotary sawing blade having a sawing edge, a rotary trimming blade having a trimming edge, said blades being disposed substantially in a common cutting plane at right angles to the axis of said stationary shaft and substantialLy in opposed relation to each other, carrier means mounting said blades on said support for movement through a cutting stroke in said common cutting plane from a retracted position spaced from said stationary shaft to an advanced position contiguous to said shaft, said sawing edge being disposed radially inwardly of said trimming edge by a fixed increment such that said roll of material is first cut by said sawing blade and then trimmed by said trimming blade during said cutting stroke, and means operatively connected to said sawing blade and to said trimming blade for rotating said blades.

7. In a rotary knife cutting machine, a frame, roll-supporting and turning means on said frame including a stationary shaft adapted to receive and support a roll of material which is to be cut into a plurality of tapes while turning about the shaft axis, a knife carriage, means mounting said knife carriage on said frame for longitudinal traverse along a path parallel to said shaft axis, a sawing knife carrier mounted on said knife carriage for movement toward and away from said stationary shaft, a rotary sawing knife having a sawing edge mounted on said sawing knife carrier for rotation about a sawing axis parallel to said shaft axis, a trimming knife carrier mounted on said knife carriage for movement toward and away from said stationary shaft, a rotary trimming knife having a trimming edge mounted on said trimming knife carrier for rotation about a trimming axis parallel to said shaft axis, said sawing and trimming knives being disposed in a common cutting plane extending at right angles to said shaft axis, said sawing edge being disposed radially inwardly of said trimming edge such that said roll of material is first cut by said sawing knife and then trimmed by said trimming knife during movement of said knives toward said stationary shaft, means operatively connected to said sawing and trimming knife carrier for moving said sawing and trimming knives toward and away from said stationary shaft during a cutting cycle while maintaining the radial relationship between said sawing and trimming edges, means operatively connected to said sawing knife for rotating said knife at a sawing speed, and separate means operatively connected to said trimming knife for rotating said trimming knife at a trimming speed.

8. A cutting mechanism for use in a rotary knife cutting machine including a frame, roll-supporting and turning means on said frame including a stationary shaft adapted to receive and support a roll of material which is to be cut into a plurality of tapes while turning about the shaft axis, a knife carriage and means mounting said knife carriage on said frame for longitudinal traverse along a path parallel to said shaft axis, said cutting mechanism including a sawing knife carrier adapted to be pivotally mounted on said knife carriage for movement toward and away from said stationary shaft, a rotary sawing knife having a sawing edge rotatably mounted on said sawing knife carrier for rotation about a sawing axis parallel to said shaft axis, a trimming knife carrier adapted to be pivotally mounted on said knife carriage for movement toward and away from said stationary shaft, a rotary trimming knife having a trimming edge rotatably mounted on said trimming knife carrier for rotation about a trimming axis parallel to said shaft axis, said sawing and trimming knives being disposed in opposed relation to each other in a substantially common plane extending at right angles to said shaft axis, said sawing edge being disposed radially inwardly of said trimming edge by a fixed increment and being of a lesser width then said trimming edge such that said roll of material is first cut by said sawing knife and then trimmed by said trimming knife during movement of said knives toward said stationary shaft, and means for rotating said knives.

9. A cutting mechanism for cutting a roll of material into plural tapes comprising; a support, a rotary sawing blade having a sawing edge, a rotary trimming blade having a trimming edge, said blades being disposed substantially in a common plane at right angles to the longitudinal axis of said roll and substantially in opposed relation to each other, carrier means mounting said blades on said support for movement through a cutting stroke in said common plane from a retracted position spaced from said longitudinal axis to an advanced position contiguous thereto, said sawing edge being disposed radially inwardly of said trimming edge by a fixed increment such that said roll of material is first cut by said sawing blade and then trimmed by said trimming blade during said cutting stroke, and power means for driving one of said blades.