US3731570A

US3731570A - Trim tensioning limiter

Info

Publication number: US3731570A
Application number: US00185961A
Authority: US
Inventors: S Nelson
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1971-10-04
Filing date: 1971-10-04
Publication date: 1973-05-08
Anticipated expiration: 1990-05-08

Abstract

Apparatus for conveying continuous web edge trim under tension, with means for severing such trim when it is subjected to longitudinal tensions above a predetermined value to thereby prevent the travel of excessive tensions back to locations at which web trimming is being effected.

Description

UNITED STATES PATENTS United States Patent [1 1 1111 3,731,570 Nelson 1 1 May 8, 1973 [54] TRIM TENSIONING LIMITER 2,609,875 9 1952 Zuck ..83/579 1,419,302 6/1922 Pape ...83/370 X Inventori Seddon Nelson, Frederwksburg, 1,397,911 11/1931 Tossi'zza ..83/370 Va. 1,369,853 3/1921 Tetetleni ..83/579 [73] Ass1gnee: FMC Corporation, Ph1lade1ph1a, Pa. Primary Examiner Andrew R. Juhasz [22] Filed: Oct. 4, 1971 Assistant Examiner-Leon Gilden Att Th R.OM 11 11 1. 21 Appl. No.: 185,961 omas a eye a [57] ABSTRACT [52] U.S.CI. ..83/370, 83/359,83/579, Apparatus for conveying continuous web g trim 83/923 under tension, with means for severing such trim when [51] Int. Cl. ..B26d 5/38 it is ubjected to longitudinal tensions above a [58] Field Of Search ..83/370, 359, 923, predetermined value to thereby prevent the travel of 83/112,161,579 excessive tensions back to locations at which web trimming is being effected. [56] References Cited 11) Claims, 6 Drawing Figures PAIENIED M 191s SHEET 1 OF 2 PATENTEB HAY 81975 SHEET 2 OF 2 TRIM TENSIONING LIMITER The present invention is directed to conveying, under tension, edge trim slit from continuous webs, and particularly to an apparatus for isolating the locations of web slitting from excessive tensions applied to the trim itself.

In typical web slitting operations, edge trim removed from individual webs by each of a number of separate slitters is combined together continuously and concomitantly with its formation and is conveyed to a suitable collection station. Conveyance of such combined mass of web edge trim is generally achieved by delivering air under pressure through a header into which open ducts leading from each of the separate web slitters. At the respective slitters the individual ducts themselves are bifurcated to provide branches having venturi suction inlets which are positioned at the locations of web slitting to receive edge trim immediately after it is formed.

Excessive tension applied to edge trim is transmitted back to slitting locations at which such trim is formed and generally results in at least a break in the continuity of the trim itself. As a more concrete example, web slitters supplying edge trim to a common discharge header are often operated at different speeds, with the speed of each slitter being dictated, for example, by the particular type or characteristics of the web being slit or its roll formation. Under such operating conditions, edge trim formed by the separate web slitters will travel toward and into the discharge header at different rates. It has been discovered that within the discharge header itself the more rapidly advancing edge trim tends to bundle or warp itself about the slower traveling edge trim. This bundling of edge trim may accelerate the slower moving trim. However, a more serious consequence is that the bundled trim acts as a plug which assumes an intermittent movement as it is propelled by the air flowing through the discharge header. The erratic pulsating movement of the bundled trim is transmitted to trailing portions of the edge trim and, much too often, subjects the slower moving edge trim to such tensions as to rupture the same at locations of web slitting.

Once such break occurs at a web slitting site, the edge trim which continues to be formed at such location tends to wrap itself about the different pull and idler rolls of the slitter and/or cause the slit web to break, and/or be trapped inbetween overlying layers of slit web during its winding into rolls. Correction of these difficulties can be achieved only by stopping operation of the slitter to removed edge trim from slitter rolls and/or splice ruptured web ends. Such clean-up measures, however, are costly, often resulting in damage to the slitter rolls, waste of materials and, if

web splicing is necessary, providing an inferior end.

product. Accordingly, a primary object of this invention is to provide a generally new or improved and more satisfactory apparatus for conveying edge trim from a web slitter.

Another object is the provision of improved apparatus for more efficiently removing edge trim from web slitters which are operated at different speeds.

Still another object is to provide an apparatus for conveying edge trim from a web splitter under longitudinal tension, with the web slitter itself being isolated from excessive tensions which may be applied to edge trim during its conveyance.

A further object is the provision of an apparatus in which edge trim slit from a continuous web is subjected to longitudinal tension to convey the same and is automatically severed when the longitudinal tension applied thereto exceeds a predetermined level.

A still further object of this invention is to provide apparatus for use in a system in which web edge trim is conveyed under longitudinal tension simultaneously from a plurality of web slitters operating at different speeds, with such apparatus automatically regulating the degree of tension exerted upon the edge trim at individual locations of web slitting.

These and other objects of the invention are achieved by an apparatus for conveying continuous edge trim away from a web slitter under longitudinal tension applied thereto, with the web slitter being isolated from such tensions exerted on the edge trim as might cause the continuous trim to break at a location of slitting.

As in conventional trim removal systems, web edge trim is advanced to and beyond the apparatus of the present invention through a duct which, together with other similar ducts from other individual web slitters, opens into a common header. A fluid, such as air, is caused to flow through this common header, creating a suction effect at the inlets of the individual ducts, and conveying the edge trim which is within such header to a suitable collection site. Preferably, each of the individual ducts of such trim removal system is equipped with the apparatus of the present invention. However, for the sake of clarity and simplicity the apparatus of the present invention is hereafter described as incorporated into only one of such ducts.

More particularly, the apparatus includes a cylinder which is disposed along the path of trim advancement through a duct and about the periphery of which the trim is adapted to be looped. This cylinder is supported for rotation about its longitudinal axis under torque applied thereto by the tensioned trim as it is advanced over the cylinder periphery. Included also in the apparatus are means for resisting cylinder rotation when the tension on the edge trim beyond the cylinder exerts thereon a torque less than a predetermined value. Operatively connected with the cylinder is a cutting blade which is projected across the path of and severs the web edge trim looped about the cylinder periphery when the cylinder is rotated under a torque at least equal to a predetermined value.

A baffle within the trim-conveying duct, together with adjacent walls of such duct, cooperate with the cylinder to define a helical passage about its periphery whereby edge trim is looped about the cylinder periphery during its advancement through the duct.

The cutting blade employed in; the apparatus of the present invention is supported within the cylinder for pivotal movement about an axis substantially parallel to that of the cylinder. A slot, extending substantially parallel to the cylinder axis, opens along the cylinder periphery and it is through this slot that the cutting blade is projected when the cylinder is rotated. Blade projection is preferably achieved by a plate cam which is fixed to the cylinder at substantially right angles to its axis and includes a cam surface for urging the bladeabout its pivot axis when the cylinder is turned.

Cylinder rotation, and thus blade projection, is effected when the tension exerted on the web edge trim beyond the cylinder; that is, downstream from the cylinder, subjects such cylinder to a torque at least equal to a predetermined value. Upon projection of the cutting blade, the edge trim looped about the cylinder periphery is severed. The web edge trim and slitter located upstream from the cylinder are thereby isolated from tensions which may well have caused such trim to break at locations of web slitting. Since severance of the edge trim, as described, occurs on the cylinder itself, no difficulties are experienced by the newlyformed leading end of the edge trim in lacing itself through the portion of the duct beyond the cylinder.

With the apparatus of the present invention, tensions exerted on the advancing edge trim which normally have no significant affect on web slitting operations are permitted to travel back to the web slitting locations. Such tensions may apply torques to the cylinder which will tend to rotate the same. Under these conditions, however, cylinder rotation is resisted by a counteracting moment as provided by a tension spring or weight acting on the free end of a lever arm which is fixed to the cylinder itself.

The apparatus of the present invention is adapted for use with a variety of flexible web materials, as for example, films formed of thermoplastic materials, cellulose films, such as paper and cellophane, fabrics, etc.

In the drawing,

FIG. 1 is a,perspective view diagrammatically illustrating the useof the apparatus of the present invention during web slitting operations;

FIG. 2 is a side view of the apparatus of the present invention, with a portion thereof removed;

FIG. 3 is a vertical section taken through the apparatus shown in FIG. 2 substantially along the lines III-' --III;

FIG. 4 is a perspective view of the apparatus shown in FIG. 2;

FIG. 5 is a view similar to FIG. 4 with portions of the apparatus being removed to show the interior construction thereof; and

FIG. 6 is broken plan view of the apparatus shown in FIG. 2. v

Illustrated in FIG. 1 is a typical web slitting operation wherein a continuous web 11 is drawn from a mill or supply roll, passed over

spaced guide rolls

13 and 15, and, during such passage, slit by fixed blade, such as indicated at 17, to remove

irregular edge portions

19 and 21. Concomitantly with the edge slitting, the web 11 may also be slit into a number of separate webs, as shown at 23 and 25, which are transferred by a roll 27 to

cores

29 and 31 and wound into rolls.

The

edge portions

19 and 21 trimmed from web 11 are laced over a guide roll 33 and passed into branches 35 of a duct 37 which opens into a header 39. Air is caused to flow through the header 39, as indicated at 41, creating a venturi effect at the entrances of the branches 35 of the duct 37 which assists in drawing the

edge trim

19 and 21 therein. Edge trim from other web slitters, not shown, is also delivered into the header 39 by separate ducts 43 and, together with the edge trim from the duct 37, is conveyed through such header to a suitable collection station.

As best seen in FIGS. 2 and 4, the duct 37 includes inlet and

outlet sections

45 and 47 which are arranged with adjacent ends thereof in side-by-side relationship along the length of a cylinder 49. The duct section 45 is generally rectangular in cross-section and includes a pair of

opposing walls

51 and 53 which are disposed in converging relationship adjacent to the cylinder 49 to insure smooth edge trim delivery yet minimize fabrication costs. An arcuate wall 55 extends from the wall 51, in spaced and generally concentric relationship with the cylinder 49, and is fixed at 57 the wall 53, as by welding. A much shorter arcuate wall 59 projects from the wall 53 with its free end 61 located adjacent to and along a plane extending generally tangent tothe periphery of the cylinder 49.

The duct section 47 is also of rectangular cross-section and includes opposing

walls

63 and 65 An arcuate wall 67 extends from the wall 63, in spaced and concentric relationship with the cylinder 49, and is fixed to the opposing wall 65. The wall 65, on the other hand, extends beyond the arcuate wall 67 and terminates with a lip 69 which is flexed toward the periphery of the cylinder 49, as best shown in FIG. 2.

As best seen in FIG. 3, opposing walls 71 and 73 of the duct section 45 terminate substantially along a plane passing through the axis of the cylinder 49, while ends of corresponding walls 75 and 77 of the duct section 47 are spaced from such plane. The

arcuate walls

55 and 67 are of like radius and are connected to each other at 79 and, to the duct section walls 75 and 71, respectively, at 81 and 83. The

arcuate walls

55 and 67 may, of course, be made from a single piece of materi-' al. Projecting from the

arcuate walls

55 and 67 are flanges 85 to which are secured end plates .87 and 89.

Fixed within and at substantially right angles to the axis of the cylinder 49 are a pair of plates 91 which, in turn, are keyedv at 93 to a shaft 95. As shown in FIG. 6, the ends of the shaft 95 extend through suitable openings in the

end plates

87 and 89 which will permit such shaft to rotate freely; that is, with no binding thereof. I

Portions of the plates 91 have been removed or cut away as indicated at 97 to provide abutment and camming surfaces 99 and 101, respectively. Extending through these cut-away portions 97 of the plates 91 is a shaft 103 which, like the cylinder shaft 95, is supported by the

end plates

87 and 89 for free rotary movement. A lever arm 105 is keyed at 107 to the cylinder shaft 95 and is urged in a counterclockwise direction, as viewed in FIG. 2. by a tension spring 109. The force exerted by the spring 109 serves to maintain the cylinder 49 in a position in which the abutment surfaces 99 of the plates 91 rest against the shaft 103.

Welded or otherwise fixed to the shaft 103 is a plate 111 to which is secured a cuttingblade 113. The cylinder 49 is sloted at to permit the cutting blade 113 to be projected from within the cylinder and beyond its periphery. As will be more apparent hereafter, projection of the blade 113 is achieved by rotating the cylinder clockwise, as viewed in FIGS. 2, 4 and 5, whereby the camming surfaces 101 on the plates 91 urge the blade 113 about the axis of the shaft 103 and ultimately into a position as shown by broken lines in FIG. 2.

As heretofore mentioned, the

edge trim

19 and 21 from the web 11 is combined within the duct 37 as indicated at 117 in FIG. 5 and, after passage through the duct inlet sections 45 and over the arcuate wall 59, is laced helically about the periphery of the cylinder 49 and into the duct outlet section 47.

Helical passage of the edge trim 117 about that portion of the cylinder 49 which is aligned with the inlet section 45 is encouraged by a baffle 119, the

end portions

121 and 123 of which bear against the wall 71 of the duct inlet section 45 and the end plate 87, respectively. The outer periphery of the baffle 119 engages with the inside surface of the arcuate wall 55, while its inner periphery is spaced from the periphery of the cylinder 49 to avoid binding with the cylinder during its rotation As best seen in FIG. 2 the inner periphery of that portion of the baffle 119 which extends between the cylinder slot 115 and the wall 71 of the duct inlet section 45 is substantially concentric with the shaft 103 to facilitate the projection of the blade 113 during clockwise rotation of the cylinder. Any tendency for the edge trim 117 to wedge in between the end wall 89 and the end of the cylinder adjacent thereto is minimized by a collar 125 which is fixed to such end wall and encircles the cylinder 49. The inner surface of the collar 125. is spaced from the cylinder periphery to permit the cylinder to rotate without binding.

As heretofore mentioned, the apparatus of the present invention is intended to isolate a web slitter from tensions which, when applied to the edge trim being conveyed, ordinarily cause such edge trim to break at one or more locations of web slitting. Such excessive tensions may arise beyond or downstream from the cylinder 49 as a result of bundling of trim within the header 39, as previously described. In the absence of excessive tensions, the mass of continuous edge trim travels smoothly through the header 39 and the cylinder 49 will assume a position as illustrated in FIGS. 2--5, wherein the abutment surfaces 99 of the plates 91 are engaged with the shaft 103 and the blade 1 13 is fully retracted within such cylinder.

When tensioned beyond the cylinder 49, the edge trim 117 applies to such cylinder a torque which tends to rotate the same in a clockwise direction, as viewed in FIGS. 1, 2, 4 and 5. Cylinder rotation is resisted by the force applied by the spring 109 and obviously, its tension force must be such as to counterbalance that torq'ue, less than a predetermined value, to which the cylinder 49 may be subjected. Once the countermoment provided by the spring 109 is overcome, the cylinder 49 together with its shaft 95 rotates clockwise, urging the camming surfaces 101 of the plates 91 against the blade 113 andcausing such blade to project beyond the cylinder periphery and through the edge trim 117 which is in the path of such blade. The camming surfaces 101 are shaped to effect projection of the blade 113 during rotation of the cylinder 49 through an arc of about 60. Before this occurs, the ten sion applied to the edge trim 117 beyond the cylinder 49 will be reduced by friction between the trim and cylinder, thus isolating the slitter from such smaller tension peaks without severing of the edge trim 117.

Once severed, the edge trim l 17 beyond the cylinder 49, moves freely through the duct section 47 and header 39, the cylinder 49 returns to its position as shown in FIGS. 2-5 with the blade 1 13 being retracted, and the newly formed leading end of the edge trim l 17 laces itself through the duct outlet section 47.

It is to be understood that changes and variations may be made without departing from the spirit and scope of the present invention as defined in the appended claims. I I

Iclaim:

1. Apparatus for conveying edge trim from a web slitterincluding means for advancing continuous web edge trim under longitudinal tension concomitantly as it is slit from a web, a cylinder disposed along a path of trim advancement and about the periphery of which such trim is adapted to be looped, means supporting said cylinder for rotation about. its longitudinal axis under torque applied by the tensioned edge trim as it is advanced thereover, means for resisting rotation of said cylinder when the tension on the edge trim beyond said cylinder exerts on such cylinder a torque of less than a predetermined value, a cutting blade, and means car ried by said cylinder for projecting said cutting blade across the path of and severing the web edge trim looped about the cylinder periphery when said cylinder is rotated under a torque at least equal to such predetermined value.

2. Apparatus as defined in claim 1 wherein said cylinder includes a slot opening along its periphery and extending substantially parallel to the cylinder axis, and pivot means for supporting said cutting blade within said cylinder for movement about an axis substantially parallel to said cylinder. 1

3. Apparatus as defined in claim 2 wherein said blade projecting means includes a cam fixed within said cylinder for urging said cutting blade about its pivot axis when said cylinder is rotatedto thereby project the cutting edge of said blade beyond the periphery" of said cylinder. r

4. Apparatus as defined in claim 3 wherein said cam is a plate positioned within and fixed to said cylinder at substantially right angles to its axis of rotation, said plate having a surface which is adapted to rest against the cutting blade pivot means in the absence of torque application to said cylinder, and a cam ming surface which engages with said cutting blade ata location spaced from its pivot axis when said cylinder is rotated.

5. Apparatus as defined in claim 1 wherein said mean for resisting cylinder rotation includes a'lever arm fixed at one end to rotate with said cylinder, and'a spring extending between a fixed structure and the free end of said lever arm for applying a force to saidcylinder which is slightly less than and counter to the torque of predetermined value. j

6. Apparatus as defined in claim 3 wherein said means for resisting cylinder rotation includes a lever arm fixed at one end to rotate with said cylinder,and a 9. Apparatus as defined in claim 3 wherein said cam is shaped to effect projection of said cutting blade during a rotation of the cylinder through an angle of about 60.

10. Apparatus as defined in claim 5 wherein said cam is shaped to effect projection of said cutting blade during a rotation of the cylinder through an angle of about 60.

Claims

1. Apparatus for conveying edge trim from a web slitter including means for advancing continuous web edge trim under longitudinal tension concomitantly as it is slit from a web, a cylinder disposed along a path of trim advancement and about the periphery of which such trim is adapted to be looped, means supporting said cylinder for rotation about its longitudinal axis under torque applied by the tensioned edge trim as it is advanced thereover, means for resisting rotation of said cylinder when the tension on the edge trim beyond said cylinder exerts on such cylinder a torque of less than a predetermined value, a cutting blade, and means carried by said cylinder for projecting said cutting blade across the path of and severing the web edge trim looped about the cylinder periphery when said cylinder is rotated under a torque at least equal to such predetermined value.

2. Apparatus as defined in claim 1 wherein said cylinder includes a slot opening along its periphery and extending substantially parallel to the cylinder axis, and pivot means for supporting said cutting blade within said cylinder for movement about an axis substantially parallel to said cylinder.

3. Apparatus as defined in claim 2 wherein said blade projecting means includes a cam fixed within said cylinder for urging said cutting blade about its pivot axis when said cylinder is rotated to thereby project the cutting edge of said blade beyond the periphery of said cylinder.

4. Apparatus as defined in claim 3 wherein said cam is a plate positioned within and fixed to said cylinder at substantially right angles to its axis of rotation, said plate having a surface which is adapted to rest against the cutting blade pivot means in the absence of torque application to said cylinder, and a camming surface which engages with said cutting blade at a location spaced from its pivot axis when said cylinder is rotated.

5. Apparatus as defined in claim 1 wherein said mean for resisting cylinder rotation includes a lever arm fixed at one end to rotate with said cylinder, and a spring extending betweeN a fixed structure and the free end of said lever arm for applying a force to said cylinder which is slightly less than and counter to the torque of predetermined value.

6. Apparatus as defined in claim 3 wherein said means for resisting cylinder rotation includes a lever arm fixed at one end to rotate with said cylinder, and a spring extending between a fixed structure and the free end of said lever arm for applying a force to said cylinder which is slightly less than and counter to the torque of predetermined value.

7. Apparatus as defined in claim 3 wherein said web edge trim advancing means includes walls defining a duct within and across which said cylinder is disposed, a fixed baffle within said duct cooperating with walls of said duct and the periphery of said cylinder to define a helical passage extending about said cylinder and means for delivering a fluid under pressure through said duct.

8. Apparatus as defined in claim 7 wherein said cam is a plate positioned within and fixed to said cylinder at substantially right angles to its axis of rotation, said plate having a surface which is adapted to rest against the cutting blade pivot means in the absence of torque application to said cylinder, and a camming surface which engages with said cutting blade at a location spaced from its pivot axis when said cylinder is rotated.

9. Apparatus as defined in claim 3 wherein said cam is shaped to effect projection of said cutting blade during a rotation of the cylinder through an angle of about 60*.

10. Apparatus as defined in claim 5 wherein said cam is shaped to effect projection of said cutting blade during a rotation of the cylinder through an angle of about 60*.