US3243844A

US3243844A - Longitudinal web stretching machine

Info

Publication number: US3243844A
Application number: US363249A
Authority: US
Inventors: Nash John Crandon
Original assignee: Marshall and Williams Corp
Current assignee: Marshall and Williams Corp
Priority date: 1964-04-28
Filing date: 1964-04-28
Publication date: 1966-04-05
Anticipated expiration: 1983-04-05
Also published as: DE1460691A1; GB1013980A

Description

April 5, 1966 J. c. NASH 3,243,844

LONGI'IUDINAL WEB STRETGHING MACHINE Filed April 28, 1964 7 Sheets-Sheet 1 INVENTOR JOHN CRANDON NASH MM 5 M 36mm AT TOR N EY April 1966 J. c. NASH 3,243,844

LONGITUDINAL WEB STRETCHING MACHINE Filed April 28, 1964 '7 Sheets-Sheet 2 INVENTOR.

\ JOHN CRANDON NASH ATTORNEY April 5, 1966 Filed April 28, 1964 LONGITUDINAL WEB STRETGHING MACHINE 7 Sheets-Sheet 3 Q Q Ma gg m \QI Q INVENTOR. \Q Q JOHN CRANDON NASH ATTOR N EY April 1966 J. c. NASH 3,243,844

LONGITUDINAL WEB STRETCHING MACHINE Filed April 28, 1964 7 Sheets-Sheet 4 ATTORNEY April 1966 J. c. NASH} 3,243,844

LONGITUDINAL WEB STRE'I'GHING MACHINE Filed April 28, 1964 7 Sheets-Sheet 5 I 4 ll \n INVENTOR- F168 JOHN CRANDON NASH m Mun ATTORNEY 7 Sheets-Sheet 6 .iwmymuw ATTO R N EY April 5, 1966 J. c. NASH LONGITUDINAL WEB STRETCHING MACHINE Filed April 28, 1964 JOHN CRANDON NASH Jung FIG. IO

FIGIZ April 5, 1966 J. c. NASH 3,243,844

LONGITUDINAL WEB STRETCHING MACHINE Filed April 28, 1964 7 Sheets-Sheet 7 JOHN CRANDON NASH B1 ATTORNEY United States Patent 3,243,844 LONGIIUDINAL WEB STRETCHING MACHENE John Crandon Nash, Providence, 12.1., assignor to Marshall and Williams Corporation, Providence, ELL, a corporation of Rhode Island Filed Apr. 28, 1964, Ser. No. 363,249

17 Claims. (Cl. 18-1) The present application is a continuation-impart of United States patent application Serial No. 230,491 filed October 15, 1962, for a Longitudinal Web Stretching Machine, now United States Patent No. 3,208,100 dated September 28, 19 65.

This invention relates to apparatus for stretching webs and films and more particularly it relates to a machine for longitudinally stretching plastic film in a plastic or heat softened state to increase the film length and reduce the film thickness.

An object of the present invention is to provide a machine with apparatus for heating a continuous web of plastic film to a predetermined temperature at the marginal line of stretch tension and to provide draw rolls for longitudinally stretching the continuous web as it passes from feed rolls to draw rolls.

Another object of the present invention is to provide a machine, for longitudinally stretching a running web of plastic film, between a set of feed rolls and a set of draw rolls. The draw rolls being rotated at varying relative speeds, in relation to the feed rolls at varying selected relative distances from the feed rolls. The surface temperatures varying on the set of feed rolls and the draw rolls.

Other objects of the present invention will become apparent in part and be pointed out in part in the following specification and claims.

The present application is an improvement over my co-pending application Serial No. 230,491 filed October 15, 1962,'for a. Longitudinal Nob Stretching Machine.

With the advent of increased use of plastic film for a variety of articles there has developed a need to longitudinally stretch a web of plastic film to provide a web of desired width and thickness. Efforts have been made to initially manufacture a web of desired width and thickness. Such efforts have not been commercially successful. It has been found that the successful stretching of a plastic web requires four physical conditions:

(1) The heating of the plastic web or film to a proper degree to heat soften or plastercise the film to a proper consisting;

(2) A predetermined stretch ratio of the film must be provided for;

( 3) A predetermined stretch rate must be provided for;

(4) The heat softened film must be set after stretching.

These four conditions are provided for in the present longitudinal web stretching machine. (1) The film to be stretched is heated to a proper degree by a set of feed rolls. A heating lamp is provided to add additional heat when necessary at the marginal line of initial stretching. (2) The stretch ratio of the plastic film is provided for by the difference in linear speeds between the feed rolls and the draw rolls. (3) The stretch rate of the plastic film is determined by the linear distance between the two points of tangency on adjacent draw rolls of the two separate sets of rolls, namely feed roll and draw roll. This linear distance is variable through the adjustment feature of pivoting the draw rolls toward and away from the feed rolls. (4) The plastercised stretched film is set by the surface temperature of the second set of draw rolls. In addition, the adjustable feature facilitates the initial threading of the web around both sets of draw rolls.

Referring to the drawings in which similar characters of reference indicate corresponding parts:

FIGURE 1 is a perspective view of the new and im proved longitudinal web stretching machine as viewed from the front left corner of the machine.

FIGURE 2 is a front elevational view of the machine.

FIGURE 3 is a plan view of the machine.

FIGURE 4 is a vertical cross sectional view through the machine, taken on line 44 of FIGURE 2, looking in the direction of the arrows.

FIGURE 5 is a view similar to FIGURE 4 showing the set of draw rolls pivoted the maximum distance away from the cooperating set of feed rolls.

FIGURE 6 is a left side elevational view as viewed in FIGURE 1.

FIGURE 7 is a vertical cross sectional view, partially broken away, taken along line 77 of FIGURE 6, showing the construction of the gage control mechanism.

FIGURE 8 is a cross sectional view taken on line 8-8 of FIG. 7.

FIGURE 9 is a fragmentary cross sectional view, taken on line 99 of FIGURE 6.

FIGURE 10 is a side elevational view of a detail showing of a side frame of the machine.

FIGURE 11 is a side elevational view of a detail showing of a pivotal arm.

FIGURE 12 is a fragmentary schematic perspective view taken generally upon line 4-4 in FIGURE 2, looking in the direction of the arrows from the rear left corner of the machine.

FIGURE 13 is a vertical cross sectional view through the machine taken along line 13-13 of FIG. 2, looking in the direction of the arrows.

FIGURE 14 is a fragmentary schematic perspective view, illustrating the construction for adjusting the auxiliary heating means.

According to the invention the new and improved longitudinal web stretching machine consists of a frame having left side vertical wall 11 and an opposite and parallel right side vertical wall 12.

Spacing brackets

15, 16 and 17 are welded on opposite ends, respectivelypto left and right side vertical Walls 11 and 12. A plate 18 may be welded to spacing brackets 15 and 1-6.

An angle iron 19 may be'welded to right side vertical wall 12 and to spacing

brackets

15, 16. A similar angle iron 20 may be welded to left side vertical wall 11 and to spacing

brackets

15, 16.

FIGURE 10 represents in detail, right side vertical wall 12, provided with drive shaft bearing supports 21, 2 2; bearing support 23 slotted at 24, hearing support 25 slotted at 26 and a notch consisting of a bottom 27, a backstop 23 and a front stop 29. Left side vertical wall 11 is identical in construction to right side vertical wall 12. When reference is made hereinafter'to left side vertical wall 11, the sufiix A will be added to the reference numerals appearing in FIGURE 10.

FIGURE 11 represents in detail a right side pivoted arm 31) provided with a bearing support 31, a bearing support 32 slotted at 33, and a bearing support 34 slotted at 35. Left side pivoted arm 36 is identical in construction to right side pivoted arm 31 When reference is made hereinafter to left side pivoted arm 36, the suffix A will be added to the reference numerals appearing in FIGURE 11.

Bearings 42, 43 are fixed in bearing supports 21, 22, respectively, in right side vertical Wall 12. Similarly, hearings 42A, 43A are fixed in bearing supports 21A, 22A, respectively, in left side vertical *wall 11'. Drive

shafts

44, 45 are rotatively mounted on opposite ends, respectively, in

bearings

42, 42A and 43, 43A.

A suitable bearing (not shown) is fixed in bearing support 31. Similarly, a further bearing (not shown) is Patented Apr. 5, 1966 fixed in bearing support 31A. Right side pivoted arm 39 is pivotally mounted upon drive shaft 44 through the bearing in bearing support 31. Left side pivoted arm 36 is pivotally mounted upon drive shaft 44 through a bearing in bearing support 31A.

A stop rod 47 is fixed on opposite ends, respectively, to left and right side pivoted

arms

36, 30 and is adapted to abut back stop 23 and front stop 29. In this manner right and left side pivoted

arms

30, 36 are limited in their pivotal movement.

A double acting air cylinder 50, Model PDSCB3CR 50, five inch stroke, three inch bore, manufactured by Bellows Valvair Company, Akron, Ohio, is provided to pivot

arms

30, 36.

A bracket 48 is fixed on opposite ends, respectively, to right and left side pivoted

arms

30, 36. A power unit, in the form of an air cylinder 50 is fastened on one end to spacing bracket 15 and on the other end to bracket 48 to pivotally actuate and control the pivotal movement of right and left side pivoted

ams

30, 36. A pair of spacer bars 49 and 51 (see FIGURES 1, 4, 5 and 12) are connected at their opposite ends to

arms

30 and 36 and serve to connect and provide rigidity to the upper end of these pivot arms.

A set of feed rolls and a set of draw rolls are provided for stretching the web. The stretching operation takes place between adjacent rolls of the opposite sets of rolls.

The sets of draw rolls may constitute one roll in each set because the stretch ratio and stretch rate are determined by the relationship between these two rolls. However, for purposes of supplying sufiicient heat to the web and to prevent slippage of the web on the draw rolls, two, three or more rolls may constitute a set of draw rolls. For purposes of illustration two rolls are shown as constituting a set of draw rolls.

Four calendar rolls, here referenced as 37, 38, 40 and 41 are provided for accommodating the web to be processed on the machine. Each of these draw rolls preferably takes the form of the draw roll shown and described in United States Patent No. 2,498,662, or in United States Patent No. 1,651,502 or in United States Patent No. 3,120,867 dated February 11, 1964, by John Crandon Nash. Briefly, these

rolls

37, 38, 40 and 41 in clude internal compartments or chambers indicated at 37A, 38A, 40A, and 41A, respectively which are adapted to communicate with a source of fluid. This fluid, which is heated to a predetermined temperature, acts to heat the surface of each of the rolls thereby serving to heat the web passing around the rolls. Obviously, while the rolls are referred to as being heated, they or any of them, could be cooled or otherwise surface temperature controlled to the end that a desired temperature environment for a web being handled on the machine can be achieved.

To consider, now, the particular mounting of the calendar rolls, it will be observed from the drawing (FIGS. 4 and 5, for example), that these rolls are actually constituted .as two individual sets. Thus, a set of draw rolls 37, 38 is seen to be supported between the pivoted

arms

30, 36. Draw roll 37 is rotatably supported at its left hand side (see FIGS. 1 and 9) on a stub shaft 68, which said shaft may be formed integrally with this draw roll to extend therefrom. As best seen in FIG. 9 stub shaft 60 projects through and rotates on bearing 61 seated in bearing support 34A. A drive gear 69 is connected to stub shaft 60 by engagement with a key 70. This gear 69 being disposed on the outer end of shaft 69. The opposite end of draw roll 37 is provided with a projecting hollow shaft 72 which is rotatable in a bearing 74 carried within bearing support 34 (see FIGS. 3 and 11). The outer end of hollow shaft 72 has a rotary fluid coupling 76 mounted thereon to thereby provide a connection to a suitable source of fluid. Said fluid is permitted to flow through hollow shaft 72 and into the compartment 37A within draw roll 37 to thereby heat this roll as in accordance with the structure of the patents and patent application earlier cited.

In like manner as just described in connection with calendar or draw roll 37, the companion draw roll 38 of this set is supported at its left hand end on a stub shaft 78 carried in suitable hearings in left side pivoted arm 36. The outer end of shaft 78, which projects beyond the outside of arm 36 has a sprocket 80 thereon and keyed thereto so that said sprocket 80 may drive shaft 78. A gear 82 is also affixed tightly on shaft 78 in order that this gear will rotate positively with said shaft 78. The opposite end of draw roll 38 is supported on a hollow shaft 84 rotatable in a suitable bearing 86 carried in bearing support 32 of right side pivoted arm 30. The outer end of hollow shaft 84 has a fluid coupling 88 attached thereto and arranged to receive a fluid from a suitable source whereby this fluid may be conducted through hollow shaft 84 and into compartment 38A of draw roll 38. In this fashion draw roll 38 is heated.

Advantageously, a guide roll and companion nip roll or pinch roll are provided to operate cooperatively with movement of a web being carried around the diameter of draw rolls 37, 38. Accordingly, a first shaft 94 is supported for rotation in suitable bearings carried in bearing supports projecting rearwardly from the rear edges of

pivot arms

30, 36. One of these bearings is shown at 95 in FIG. 6, and in this same view the bearing support therefore may be seen at 96 carried on pivot arm 36. It will be appreciated that an identical bearing for this shaft 94 will be provided at in bearing support 96A in opposite pivot arm 30 (see FIG. 4). A guide roll 97 is secured onto shaft 94 as by a press fit to be rotatable therewith in response to frictional contact of a web being drawn thereacross. As seen in FIGS, 4, 5 and 12 guide roll 97 is situated rearwardly of draw rolls 37, 38 and approximately midway between the respective axes of these two draw rolls. Thus, guide roll 97 serves to guide the web partially around draw roll 37 (see FIGS. 4 and 5) and further serves to keep the web flat and wrinkle free as the web advances.

A companion pinch roll 98 is provided to operate in conjunction with rotation of draw roll 38. To this end a shaft 99 is rotatably mounted at its opposite ends in the outer ends of a pair of bell crank levers 100 and 100A; one of which is seen at 106 in FIGS. 4 and 5 and the opposite one of which is shown at 100A in FIG. 13.

Lever 108 is rockably supported upon a post 101 projecting outwardly from the interior wall of right side piv oted arm 30. Similarly, lever 1418A is rockably supported upon a post 101A fastened in and projecting from the interior wall of left side pivoted arm 36. A hydraulic cylinder 102 is connected to a leg 104 which, in turn, is fastened to frame bar 48 at the right hand side of the machine. A like arrangement for shaft 99 consisting of hydraulic cylinder 102A connected to a leg 104A (see FIGURE 13) provided for the distal end of shaft 99, i.e., the shaft end adjacent left side pivot arm 36 (see FIG. 13).

Pinch roll 98 is formed as an elongated cylinder, preferably of a heat-resistant frictional material press-fitted onto shaft 99 for rotation therewith. Upon actuation by hydraulic cylinder 102, pinch roll 98 can be rocked about post 101 from its inoperative position as shown in FIG. 5 to its operative position as seen in FIG. 4 wherein it presses against draw roll 38. Thus, pinch roll 98 can rotate by frictional contact with draw roll 38 to prevent the web from slipping on the draw roll and to keep the web flat.

Gear 82 has been stated as afiixed to shaft 78 for rotation therewith. This gear 82, which forms part of a gear train, acts as the driver for rotating draw roll 37 in con-- cert with rotation of draw roll 38. Thus, with reference: to FIGS. 1, 2 and 6 a pair of gears 39 and 90 are mountedv for rotation on the outer ends of

stub shafts

91 and 92; respectively, said

stub shafts

91, 92 being emhfiddfid. in;

the wall of pivot arm 36.

Gears

89 and 90 are mounted so as to enmesh with each other. Moreover, gear 89 intermeshes with gear 69 on shaft 60. In a similar manner gear 98 intermeshes with gear 82 on shaft 78.

To the end that simultaneous, positive movement may be imparted to draw

rolls

37 and 38, a relatively small diameter driver sprocket 103 is secured to drive shaft 44 for rotation therewith. An endless chain 118 passes about sprocket 108 and is engaged with sprocket 80. Thus, as drive shaft 44 is operated its power is transmitted by chain 110 to sprocket 88 whereupon draw roll 38 and its companion roll 37 are rotated. An idler sprocket 112 is rotatably mounted on a stub shaft 114 projecting outwardly from an arm 116. This arm 116 is adjustable on a post 118 extending out from the side of pivoted arm 36. Idler sprocket 112 engages chain 110 between

sprockets

80 and 108 and by suitable positioning of arm 116, this idler sprocket 112 is operable to adjust tension in chain 110.

Rolls

40 and 41 constitute a set of feed rolls operable cooperatively with the earlier described set of draw rolls, i.e., draw rolls 37, 38, in order to achieve controlled stretching of a continuous web. This set of feed rolls are fixed in position for rotation as opposed to draw

rolls

37, 38 which are pivotable about a horizontal axis.

To consider firstly the mounting for feed roll 40, this roll is supported at its left-hand end on a stub shaft 120 (see FIG. 1) which may be formed integrally with the roll, the stub shaft projecting from the roll 40 and extending through the side 11 of the machine. A suitable bearing, not illustrated, is provided in the side wall 11 from rotation of stub shaft 120. The outer end of shaft 120 has a gear 122 secured thereon as by key means (not shown). The opposite end of feed roll 49 is provided with a centerless shaft 124 (see FIGURE 3) which passes through and is rotatable on a bearing 126 pressed into the side 12 of the machine. A-fluid coupling 128 is attached to the outer end of centerless shaft 124 and provides a means for introduction of a fluid into the chamber 40A of calendar or feed roll 40.

The mounting for feed roll 41 is generally similar to that just described for feed roll 40. Feed roll 41 is carried at its left hand end on a stub shaft 130 (see FIGURES l and 2) formed integrally with the end flange of the draw roll. wall 11, through bearing 131, and has a sprocket 132 aflixed thereon as by being keyed thereto. A gear 134 is also keyed to shaft 130, this gear lying intermediate sprocket 132 and the outside of wall 11. The opposite end of feed roll 41 has a centerless shaft 136 connected thereon and extending outwardly beyond wall 12, passing through a bearing 138 in said wall 12. The outer end of centerless shaft 136 has a fluid coupling 140. In accordance with the present invention temperature controlling fluid may be admitted through fluid coupling 140, passing through centerless shaft 136 and into chamber 41A to thereby adjust the surface temperature of feed roll 41.

As in the case of the set of draw rolls 37, 38, earlier described, the feed rolls 40, 41 are provided with a cooperating guide roll and pinch roll. To this end a guide roll 142 is supported on a shaft 144. The opposite ends of shaft 144 are journalled in suitable bearings in. the walls 11 and 12 of the machine. The bearing 146 for shaft 144 in wall 11 is seen in FIG. 1. As is readily apparent in FIGS. 4 and 5 guide roll 142 acts to rotate by frictional contact with the web and to direct the web into the machine in a flat condition whereby the web is guided to feed roll 41.

A second or auixliary guide roller 148 is preferably arranged downstream, or beyond guide roller 142 to thereby assist in moving the web to feed roll 41. This further guide roller 148 is carried on an elongated shaft 158, the opposite ends of said shaft being carried in suitable bearings 152 (FIG. 1) in opposite side walls 11, 12 of the Stub shaft 130 projects beyond the outer side of machine. As is readily evident in FIGS. 4 and 5 auxiliary guide roller 148 receives the web from guide roller 142 for delivery to feed roll 41. As with guide roll 142, guide roll 148 is freely rotatable under the frictional drag of the web being drawn thereover.

A pinch roll 154 is supported at the forward end of the machine on an elongated shaft 156. In turn, the opposite ends of shaft 156 are rotatably supported in the inner ends of a pair of hell crank

levers

158, 158A, the lever 158 adjacent the right side of the machine being illustrated in FIGS. 4 and 5. The bell crank lever 158A, located adjacent the left side of the machine is shown in FIG. 13. Bell crank lever 158 is rockable on a stud 160 embedded in right side vertical wall 12 of the machine. Bell crank lever 158A is rockable on a stud 160A fastened in left side vertical wall 11. The outer or lower end of each bell crank

lever

158, 158A has a

rod

162, 162A, respectively, connected therewith. The distal end of each

rod

162, 162A is connected with a respective

hydraulic cylinder

164, 164A, for controlling the movement of pinch roll 154. By the actuation of

hydraulic cylinders

164, 164A, pinch roll 154 maybe rocked against the surface of draw roll 41 and, similarly, may be rocked away from engagement therewith. The inner end of each

hydraulic cylinder

164, 164A is suitably connected to the walls 12, 11, respectively, of the machine by brackets 166, 166A and pivot pins 167, 167A, respectively. The cylinders are therefore free to rock in conjunction with their operation of pinch roll 154. i

In order that the web may be pressed tightly onto the surface of a feed roll 40 a further pinch roll 174] is supported in opposite bell crank levers connected in walls 11, 12 of the machine much in the same manner as just described with pinch roll 154. Pinch roll 170 is mounted for rotation on a shaft 172, the opposite ends of this shaft being supported for rotation is one end of a pair of hell crank

levers

176, 176A. In FIGS. 4 and 5 there is shown the bell crank lever 176 adjacent wall 12 for mounting shaft 172 and in FIG. 13 bell crank 176A is shown adjacent wall 11 for supporting the opposite end of shaft 172. Bell crank levers 176, 176A are supported medially on

Posts

178, 178A for rockable movement thereabout.

Posts

178 and 178A are fastened, respectively, in right and left side vertical walls 12 and 11. The end of the

levers

176, 176A opposite from shaft 172 are connected to

rods

180, 180A, respectively, which joins with respective

hydraulic cylinders

182, 182A. Upon actuation of

hydraulic cylinders

182, 182A, pinch roll 170' may be rocked against the periphery of feed roll 40 to press the web thereagai-nst and may also be rocked away from this feed roll as when the web is being initially wrapped about the roll. The lower ends of

hydraulic cylinders

182, 182A are pinned at 183, 183A, to

opposite brackets

184, 184A which are, in turn fastened to right and left side vertical walls 12, 11, respectively.

The drive for feed rolls 40, 41 is received from a sprocket 186 affixed for rotation on the outer end of drive shaft 45. As best seen in FIG. 6 an endless chain 188 is passed around sprocket 186 and sprocket 132 to connect these two components together for operation. A pair of idler gears 19%), 192 are supported on respective stub shafts 194, 196'r'nounted in and projecting outwardly from the left side vertical wall 11 of the machine.

Gears

190 and 192 are enmeshed with each other. Further gear 191 is enmeshed with gear 122 on stub shaft 120 while gear 192 is enmeshed with gear 134 on stub shaft 136. In consequence thereof power is transmitted from drive shaft 45 through chain 188 to rotate feed rolls 4% 41.

A small idler sprocket 198 is positioned in the path of chain 188-for tensioning the chain. Idler sprocket 198 is held for rotation on a short shaft 200 located at one end of an arm 282. The opposite end of arm 202 is clamped onto a post 204 fixed in wall 11, so that the arm may be rocked thereabout to a suitable location after which the arm 202 is clamped to the post by bolt 206. In this way idler gear can be rocked into the path of chain 188 to be rotated thereby and to tension the chain.

The present invention includes (see FIGURES 1, 2, 3, 4, 5, 6, 7, 12 and 13) an advantageous arrangement permitting the set of

draw roll

37, 38 to be micrometer ad justed relative to the set of feed rolls 40, 41 so that the stretch distance may be accurately determined.

To this end a pair of oppositely disposed square shaped

brackets

210 and 212 are provided at the front of the machine. Square shaped bracket 210 is provided with a square shaped hollow bore 212C and a forwardly projecting arm 212D having a pair of

ears

212E, 212F. A U-shaped bracket 225 is fastened to left side vertical wall 11 as by means of welding. Trunnions 237 and 238 integrally formed in square shaped bracket 210 are pivotally mounted in U-shaped bracket 225 in bearings provided for that purpose. Square shaped bracket 212 is similarly constructed and is provided with a pair of cars 2126 and 2121-1. A U-shaped bracket 227 is fastened to right side vertical wall 12 as by means of welding. Said cars 212E, F, G, H, have aligned bores therethrough to receive opposite end sections of a cross-shaft 214. Advantageously, cross-shaft 214 has a pair of universal joints therein at 215 and 216 to insure alignment and thus free rotational movement of this shaft. A bevel gear 218 is secured onto the diameter of cross-shaft 214 within the confines of bracket 210. In like manner, a further bevel gear 220 is affixed on the outer section of cross-shaft 214 within the channel of bracket 212. A hand-wheel 222 having appropriate graduations marked on the periphery thereof is keyed onto the outer end of cross-shaft 214 adjacent wall 11. An indicator 223 (see FIGURE 6) is attached to a bracket 225 fastened to wall 11 to provide a convenient pointing means cooperable with movement of hand-wheel 222.

The square shaped hollow bores 212C accommodate threaded shafts 228, 230. Thus square shaped

brackets

210 and 212 have shafts 228, 230, respectively, projecting therethrough to accommodate

bevel gears

232, 234 and fastened thereon, respectively. Bevel gear 232 meshes with bevel gear 218. Bevel gear 234 meshes with bevel gear 220. It will, thus, be evident that rotation of crossshaft 214, as by hand wheel 222, will be effective to rotate shafts 228 and 230.

In FIG. 7 there is depicted the details of one of the square shaped

brackets

210 or 212 and its companion shaft 228 or 239. It will be understood that since the construction of each member and its related components is identicaL'reference can be directed to the features of the single structure of FIG. 7 to describe both square shaped

bracket

210, 212 related components. Square shaped hollow bore 212C accommodates opposite aligned plain bearings 239, 240 therein as by a press fit. Shaft 228 is rotatable on bearings 239, 240. The outer half, approximately, of shaft 228 is threaded as indicated at 242, and is surrounded by a relatively large diameter tube 241, said tube being connected at one of its ends to square shaped bracket 210. The threaded portion of shaft 228 serves to receive a large nut 244 in threaded engagement therewith. Nut 244 is fitted within and is slidable longitudinally of tube 241. A fiber collar 244C is slidably mounted within tube 241 and normally abuts nut 244. The rearward end of a hollow row 246 is pinned at 247 to yoke 248. Said yoke 248, in turn, projects rearwardly and is connected to the side of pivot arm 36 by a crosspin 251 It will, therefore, be seen that rotation of crossshaft 214 will impart simultaneous rotation to shafts 228 r and 239. In consequence thereof, rotation of shafts 228,

230 causes nuts 244 engaged with these shafts to move longitudinally thereof.

Actuation of air cylinder 50 will move pivot

arms

30, 36 about shaft 44 and thereby move arm 36, for example, and yoke 248 attached to hollow rod 246. In this manner hollow rod 246 is slidable Within tube 241 so that the end of tube 241 will rest against fiber washer 244C. Ro tation of hand wheel 222 will rotate shaft 228 through cross-shaft 214 and bevel gears 218, 232 and thereby position nut 244 in selected position within tube 241. Air cylinder 50 through hollow rod 246 will force fiber collar 244C against nut 244 to position pivoted

arms

30, 36 in selected position as dictated by the position of nut 244. Consequently, draw rolls 37, 38 are moved as

pivot arms

30, 36 are rocked until the precise distance is established between the draw roll 38 and feed roll 40. Draw rolls 37, 38 constitute a set of feed rolls, and draw rolls 40, 41, constitute a set of feed rolls.

The distance, known as the stretching zone, determines the rate at which the web will be stretched. Thus, the apparatus of the present invention affords a quick and accurate means for establishing the stretch distance, which in turn, contributes to high quality production from the machine.

A calibrated scale 350 (see FIGURES 6 and 7) is fastened to yoke 248 by means of rivets 351. An indicating bar 352 constructed so as to allow calibrated scale 350 to slide therethrough, is fastened to tube 241 as by means of welding. In this manner, the pivotal movement of

arms

30, 36 as dictated by air cylinder 50, may be calibrated.

The power means for the present invention (see FIG- URES 2 and 3) includes an electric motor 250 bolted to a base 251. Motor 250 is provided with a power shaft 252 onto which is operatively connected to a pulley 254. A variable speed mechanism 256 is also bolted onto base 251 and is connected to motor 250 through a driving belt 258, this belt being wrapped about pulley 254 and passing around a pulley 260 on the variable speed mechanism 256. Motor 250 is a variable speed motor of any conventional type or a conventional electric motor with a variable speed drive having control means which varies the rotational speed of shaft 252.

Variable speed mechanism 256 may be a positively variable speed mechanism such as that disclosed in United States patent application Serial No. 197,016 filed May 23, 1962, by John Crandon Nash or it may be any other variable speed transmission. As illustrated, variable speed mechanism 256 is provided with a speed control device or variator 262 which is disclosed in United States Patent 2,469,653 dated May 10, 1949. Variator 262 is provided with a shaft 264 operably connected with a pulley 266 and a shaft 267 having a pulley 268. Variable speed mechanism 256 is provided with a shaft 269 having a pulley 270. A belt 272 operatively connects pulleys 268 and 270. A further belt 274 operatively connects pulley 260 with pulley 266. Variable speed mechanism is also provided with a shaft 276 and two output shafts 278, 280. Output shaft 278 is connected through flexible coupling 282 with drive shaft 44. Likewise, shaft 280 is connected by means of flexible coupling 284 with drive shaft 45.

Shaft 264 of variator 262 is rotated at the preselected speed of shaft 276. The variator 262 will operate to change the relative speed of shaft 267 so that this shaft will rotate at a speed relative to that of shaft 264. This adjustment may be achieved by manual means not herein illustrated but which are common to variable speed control devices of the type herein contemplated. In this manner feed rolls 40, 41, which serve primarily to heat the web, are driven at preferably a slower speed than draw rolls 37, 38. To this end feed rolls 40, 41 are rotated from drive shaft 45 which is connected with output shaft 230. This output shaft 280 is rotated at a reduced speed relative to the speed of output shaft 278 through variator 262 in order that fed rolls 4%, 41 may rotate at a similar reduced speed. In contrast thereto, draw rolls 37, 38 which serve primarily to stretch the web, are rotated at a speed somewhat faster than feed rolls 40, 41 since the drive shaft 278 for these feed rolls is rotating at a relative fast speed as contrasted with that of output shaft 280. The difference in speed between the feed rolls 37, 38 as compared to that of draw rolls 40, 41 varies the pull or tension in the web stretched between them, thus providing the stretch ratio for the web. This pull or tension is also varied by the variation in stretch distance, that is to say, the distance as established between the points of tangency where the web contacts roll 38 and feed roll 40. This distance or dimension provides the stretch ratio for the web. Moreover, this distance is set or established by pivoting

arms

30, 36 to thereby generate or rock draw rolls 38, 37 about the horizontal axis of shaft 44 and, thus, achieve movement of these draw rolls relative to feed

rolls

40, 41.

The present invention includes auxiliary heating means in the event it is necessary or desirable to introduce a momentary application of heat to the web as stretch as applied. To this end a radiant heater 290 of any conventional type as, for example, the radiant heater manufactured by the Edwin LWiegand Company, Pittsburgh, Pennsylvania, catalog number RADD-3224, Chromalox Radiant Heater may be utilized. The heater 290 is so positioned as to heat the web at the line of tangency of feed roll 40 where the web is delivered therefrom toward draw roll 38. It is, of course, at this point that stretch is first applied to the web. Heater 290 is of sufiicient length to be coterminous with'fee-d roll 40. Said heater is supported by a pair of arms, one of which is shown at 292 (see FIGS. 4 and 5). A like arm is located at the opposite side of the machine for holding the opposite end of the heater 290. bracket 294 is fastened to wall 12 of the machine and a like bracket (not shown) is connected to wall 11. Arm 292 is pivotally connected to bracket 294 by stud 296 Thus, the heater 290 may be pivoted to the desired distance relative to the web running ofi feed roll 40. V

The operation of the present invention is thought to be moreor less apparent from the foregoing description. However, it will serveto summarize the operation of the machine in its operation of stretching a web of plastic film. As best seen in FIGS. 4 and 5 the web W is drawn from a suitable supply source and directed over guide roller 142 and over secondary guide roller 148. Since these rollers are freely rotatable the web may be drawn around the periphery of feed roll 41, pinch roller 154, at this time, being separatedfrom feed roll 41 to admit the web W therebetween. As seen in FIGS. 4 and 5 the web W is wrapped part way around the periphery of feed roll 41, passing therearound in a clockwise direction, after which the web W is directed upwardly and counterclockwise around feed roll 40. The web W then spans a zone z which is the stretch distance for the film and, as earlier stated,'is the distance feed roll 38 is set apart from draw roll'40. The web then passes clockwise partially around draw roll 38 whereafter the web is directed upwardly passing around draw roll 37 in a counterclockwise direction. The web W is fed off draw roll 37 to a suitable take-up.

The stretch distance or zone z is established to conform to the rate of stretch desired for the web W. This distance is set by rotating handwheel 222 which, in turn, rotates cross-shaft 214 to turn shafts 228, 230 as preyiously explained for shaft 228. In consequence thereof, draw rolls 37, 38 are positioned relative to a feed rolls 40, 41. Heated fluid is introduced into

chambers

40A, 41A through

fluid couplings

128, 140, respectively, and

centerless shafts

124, 136, respectively. In this manner heat is transferred to the surface of a feed rolls 40, 41 to heat and thereby heat soften or plasticise the plastic web W. The particular temperature of the fluid to be introduced to the

chambers

37A, 38A of respective draw rolls 37, 38 will, of course, depend on the treatment to be given the web. The fluid may be a coolant to cold set the stretch in the web or, on the other hand, may be heated fluid to heat set the web.

Variator 2 6 2 is adjusted to establish a relative rate of 'rotati on'between feed rolls 37, 38 as compared with draw rolls 40, 41. The difference in speed will determine the it) stretch ratio and, for this purpose, draw rolls 37, 38 will, obviously, be driven somewhat faster than feed rolls 40, 41.

With the machine so arranged as described above,

hydraulic cylinders

164, 132 and 102 areactuated to urge their respective nip or pinch rolls 154, and 98 against the associated rolls. These pinch rolls act to prevent the web W from slipping as great tension is placed thereon during longitudinal stretching. The pinch rolls, together with the various guide rollers, further, servesto keep the web flat and to remove wrinkles which might otherwise be presented in the web during processing. Thus, the web may be moved through the machine and be longitudinally stretched. Additionally, the web may be further heated by radiant heater 290 if desired.

FIGURE 14 illustrates a bracket construction which provides adjustable means for positioning radiant heater 2% toward and away from feed roll 40 in the stretching zone of the web.

Right side vertical wall 12 provided with bearing support 23 is provided with a plate 300. Bolts 301 secure plate 300 to wall 12 above the bearing support 23 for feed roll 40. Similarly, plate 302 is fastened to left side vertical wall 11. Bracket 294C is fastened to plate 300 by means of bolts 303. Similarly, bracket 294D is fastened to plate 302. An arm 292C provided with an elongated slot 304 is pivotally connected to bracket 294C by means of a stud 296C. A wing nut 305 rotatively mounted upon stud 296C frictionally holds arm 292C in selected or adjusted position in relation to bracket 294C. Similarly, arm 292D provided with elongated slot 304A is piyotally connected to bracket 294D by means of stud 296D. Wing nut 305A rotatively mounted upon stud 296D frictionally holds arm 292Dv in adjusted position in relation to bracket 294D.

Radiant heater 29.0 is provided on opposite ends with

brackets

307 and 307A. A stud 310 fixed to bracket 307 is slidably mounted in elongated slot 304. A wing nut 311 rotatively mounted upon stud 310 frictionally holds bracket 307 in selected or adjusted position in elongated slot 304. Similarly, a stud 310A fixed to bracket 307A is slidably mounted in elongated slot 304A. A wing nut 311A rotatively mounted upon stud 310A frictionally holds bracket 307A in adjusted position in elongated sl ot 304A.

In this manner radiant heater 290 is adjustable in parallel

elongated slots

304, 304A so as to be movable within the stretch zone and toward and away from feed roll 40. These two separate adjustments of the heater, toward and away from feed roll 40 in an up and down direction through studs 296C and 296D and toward and away from feed roll 40 through the elongated slpts allows for a positioning of the auxiliary heat in a position complimentary to the surface heat of feed roll 40.

The length of time a plastic web is held in a heat softened or plastercized condition is critical to the proper stretching of the plastic web. Where auxiliary heat is necessary to heat soften a plastic web, it must be applied at a critical location in relation to the principal heating means, such as feed roll 40.

' When two or more feed rolls 40 and 41 are used to heat and guide the web to the second set of draw rolls 37, 38, it has been found advantageous with certain types of plastic film to provide the top roll of the set, in this instance feed roll 40, with a slightly greater surface speed in this instance feed roll 41. This increased surface speed provides a take up of the web when the nature of Web material is such as to cause the web material to expand when subjected to the heat of the roll 41. The take up eliminates wrinkles in the web due to the heat expansion of the web material. Some web materials shrink when subjected to heat. The occasion may then arise when the surface speed may be reduced.

Feed roll 40 may be provided with an increase surface speed in a number of ways.

Gear train

134, 192, 190,

3 i 122 may be arranged so as to rotate shaft 120 at a preselected increased speed; or the outside diameter of feed roll 40 may be made slightly larger than the outside diameter of feed roll 41; or sprocket 132 may be removed from shaft 130 and be attached to shaft 129 to initially drive feed roll 4% with the

gear train

134, 192, 190, 122 arranged to drive feed roll 41 at a preselected relative speed to the speed of feed roll 49.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the claims.

What is claimed is:

1. A longitudinal web stretching machine comprising, draw roll means, feed roll means, said draw and feed roll means being arranged to have a continuous web pass there-between, means for rotating said draw and feed roll means to advance the web passing therebetween, and means for pivoting said draw roll means relative to said feed roll means to thereby vary the distance between said draw and feed roll means.

2. A longitudinal web stretching machine comprising draw roll means, feed roll means, said draw and said feed roll means being arranged to have a continuous web pass thereabout, drive means for rotating said draw and said feed roll means to advance the web passing thereabout, speed adjusting means operably cooperatively with said drive means to rotate said feed roll means at a different speed from said draw roll means, and means for pivoting said draw roll means relative to feed roll means to thereby very the distance between said draw and said feed roll means.

3. A longitudinal web stretching machine comprising draw roll means, feed roll means, said draw and said feed roll means being arranged to have a continuous web pass thereabout, means for adjusting the distance between said draw and said feed roll means by pivoting said second draw roll means relative to said feed roll means, and stop means for limiting the pivoting movement of said draw roll means.

4. A longitudinal web stretching machine comprising, draw roll means, feed roll means, said draw and said feed roll means being arranged to have a web of temperature sensitive material pass thereabout, means for rotating said draw and said feed roll means, means for controlling the temperature of said draw and said feed roll means to thereby control the temperature of said web passing thereabout, and means for pivoting said draw roll means relative to said feed roll means to thereby vary the distance between saiddraw and said feed roll means, said web being stretchable as it advances between said feed and said draw roll means with temperature of the web being reduced by contact with said draw roll means.

5. A longitudinal web stretching machine comprising, draw roll means, feed roll means, said draw and said feed roll means being arranged to have a web of temperature sensitive material pass thereabout, means for rotating said draw and said feed roll means, said draw roll means rotating at a speed relatively faster than said feed roll means, means for introducing a heated fluid to said feed roll means to thereby heat said feed roll means, and means for pivoting said draw roll means relative to said feed roll means to thereby vary the distance between said feed and said draw roll means, said web being stretchable as it passes from said feed to said second draw roll means and heated by said feed roll means and cool set by said draw roll means.

6. A longitudinal web stretching machine comprising a frame, a set of feed rolls rotatably supported in said frame, pivot means supported on said frame, a set of draw rolls rotatably mounted on said pivot means, drive means for rotating said-feed roller and said draw rolls independently of each other and at different selected speeds, means for heating at least said set of feed rolls, control means for pivoting said second set of draw rolls, a preselected distance from said set of feed rolls to thereby define a stretch zone for a web of material advancing from said set of feed rolls to said set of draw rolls, and pinch roll means to limit the slippage of saidweb as it is stretched in said stretch zone.

7. A longitudinal web stretching machine comprising a frame, a set of feed rolls, rotatably supported in said frame, pivot means supported on said frame, a set of draw rolls rotatably mounted on said pivot means, drive means for rotating said feed and said draw rolls independently of each other and at different selected speeds, means for heating at least said feed rolls, control means for pivoting said draw rolls, a preselected distance from said feed rolls to thereby define a stretch zone for a web of material advancing from said feed rolls to said draw rolls, auxiliary heating means operable to heat said web as it advances through said stretch zone, and pinch roll means to limit the slippage of said stretch zone.

8. A longitudinal web stretching machine comprising, a frame, a set of feed rolls rotatably supported in said frame, pivot means supported on said frame, a set of draw rolls rotatably mounted on said pivot means, drive means for rotating said set of feed and said set of draw rolls to thereby advance a thermoplastic web around said feed and draw rolls and through said machine, speed varying means associated with said drive means for rotating said set of draw rolls relatively faster then said set of feed rolls, control means for pivoting said set of draw rolls a preselected distance from said set of feed rolls to thereby define a stretch zone for the web advancing around said set of feed and set of draw rolls, fluid coupling means for introducing fluid into said set of feed and said set of draw rolls to thereby regulate the temperature of each of said sets of feed and draw rolls, at least said first set of feed rolls being heated to a temperature to heat soften said web whereby said web can be permanently stretched as it passes through said stretch zone under tension introduced by said set of draw rolls rotating relatively faster than said set of feed rolls, said set of draw rolls being at a temperature to cold set said heat softened web beyond the stretch zone and pinch roll means for limiting the slippage of said web as it is stretched in said stretch zone.

9. A longitudinal web stretching machine comprising a frame, a set of feed rolls rotatably supported in said frame, vpivot means supported on said frame, a set of draw rolls rotatably mounted on said pivot means, drive means for rotating said set of feed and said set of draw rolls to thereby advance a theromoplastic web around said feed and draw rolls and through said machine, speed varying means associated with said drive means for rotating said set of draw rolls relatively faster than said set of feed rolls, a linkage connected to said pivot means, a cross-shaft operably connected with said linkage, said cross-shaft being rotatable for moving said linkage to pivot said set of draw rolls a preselected distancefrom said set of feed rolls to thereby define a stretch zone for the web advancing around said set of feed and said set of draw rolls, a fiuid coupling for introducing a heating fluid into said set of feed rolls, said set of feed rolls being heated to a temperature to heat soften said Web whereby said Web can be permanently stretched as it passes through said stretch zone under tension introduced as said set of draw rolls rotates faster than said set of feed rolls, a fluid coupling for introducing a fluid into said set of draw rolls, to temperature control said set of draw rolls and thereby set the web in said stretched condition.

10. The combination as set forth in claim 9, including auxiliary heating means for heating said web as it passes through said stretch zone.

11. A longitudinal web stretching machine comprising, a feed and a draw roll means arranged to have a continuous web pass therebetween and to further provide a stretching zone for a web, means for pivotally adjusting said draw roll means in relation to said feed roll means to vary the distance between said feed roll means and said draw roll means and thereby provide a stretching zone for a web and the rate at which a web may be stretched, means for introducing a heated fiuid to said feed roll means to thereby heat said feed roll means to heat soften a web, means for introducing a cooling fluid to said draw roll means to thereby cool said draw roll means to set a Web, and means for rotating said feed roll means and said draw roll means at diiferent relative speeds to provide a ratio of stretch for a web, the ratio at which a web may be stretched and the rate of stretch combining to vary the width of a web between said feed rolljmeans and said draw roll means.

12. The combination as set forth in claim 11, including auxiliary heating means located in the stretching zone at said feed roll means for adding heat to a web.

13. A longitudinal web stretching machine comprising a frame, a set of feed rolls, ro-tatably supported in said frame, pivot means supported on said frame, a set of draw rolls rotatably mounted on said pivot means, drive means for rotating said set of feed rolls and said set of draw rolls independently of each other and at different selected speeds, means for heating said set of feed rolls, control means for pivoting said set of draw rolls a pre-selected distance from said set of feed rolls to thereby define a stretch zone for a web of material advancing from said set of feed rolls to said set of draw rolls, auxiliary heating means, and means for adjusting said auxiliary heating means to vary the position of said auxiliary heating means toward and away from said set of feed rolls and to vary the position of said auxiliary heating means within said stretch zone and thereby the intensity of said auxiliary heating means upon a web of material advancing from said set of feed rolls to said set of draw rolls.

14. A longitudinal web stretching machine comprising a frame, a set of feed rolls rotatably supported in said frame, pivot means supported on said frame, a set of draw rolls rotatably mounted on said pivot means, drive means for rotating said set of feed rolls and said set of draw rolls to thereby advance a thermoplastic web around said feed and draw rolls and through said machine, speed varying means associated with said drive means for rotating said set of draw rolls relatively faster than said set of feed rolls, a linkage connected to said pivot means, a cross-shaft operably connected with said linkage, said cross-shaft being rotatable for moving said linkage to pivot said set of feed rolls a preselected distance from said set of feed rolls to thereby define a stretch zone for the web advancing around said set of feed rolls and said set of draw rolls, a fluid coupling for introducing a heating fluid into said set of feed rolls, said set of feed rolls being heated to a temperature to heat soften said web whereby said web can be permanently stretched as it passes through said stretch zone under tension introduced as said set of draw rolls rotates faster than said set of feed rolls, a fluid coupling for introducing a fluid into said set of draw rolls, to temperature control said set of draw rolls and thereby set the web in said stretched condition, and pinch roll means for limiting the slippage of the web passing around said set of feed and set of draw rolls.

15. A longitudinal web stretching machine comprising a frame, a set of calender rolls rotatably supported in said frame, a pair of arms, means pivoting said pair of arms to said frame, a second set of calender rolls rotatably mounted on said pair of arms, drive means for rotating said first set of calender rolls and said second set of calender rolls independently of each other and at different relative speeds to provide a ratio of stretch for a web, a linkage, means connecting said linkage to said pair of arms, a cross shaft rotatably mounted in said frame, a hand wheel provided with graduations fixed to said cross shaft, an elongated square shaped member fixed to the said frame, a nut slidably mounted in said elongated square shaped member, a threaded shaft rotatably mounted in said square shaped nut, a first drive means connecting said cross shaft and said threaded shaft and a second drive means connecting said square Shaped nut and said linkage, whereby rotations of said hand w-heel moves saidpai-r of arms about said means pivoting said pair of arms to pivot said second set of calender rolls a preselected distance from said first set of calender rolls to thereby define a stretch zone and the rate at which a web may be stretched.

16. A longitudinal web stretching machine comprising a frame, a set of two or more feed rolls rotatably supported in said frame, one of said set of two or more feed rolls being termed a top roll, pivot means supported in said frame, a set of two or more draw rolls rotatably mounted on said pivot means, drive means for rotating said set of feed rolls and said set of draw rolls independently of each other and at different selected speeds, means for heating said set of two or more feed rolls, control means for pivoting said set of two or more draw rolls a pre-selected distance from said set of two or more feed rolls to thereby define a stretch zone for a web of material advancing from said top roll to said set of two or more draw rolls, and means for increasing the surface speed of said top roll in relation to the rest of the feed rolls in said set of two or more feed rolls.

17. A longitudinal web stretching machine comprising a frame, a set of two feed rolls comprising a top roll and a companion roll rotatably supported in said frame, pivot means supported in said frame, a set of two draw rolls rotatably mounted on said pivot means, drive means for rotating said set of feed rolls and said set of draw rolls independently of each other and at different selected speeds,vmeans for heating said set of two feed rolls, means for pivoting said set of two draw rolls a preselected distance from said top roll to thereby define a stretch zone for a Web of material advancing from said top roll to said set of two draw rolls, the outside diameter of said top roll being larger than the outside diameter of said companion roll to provide a relatively greater surface speed between said top roll and said companion roll.

References Cited by the Examiner UNITED STATES PATENTS 2,547,736 3/1951 Blake.

2,547,763 3/1951 Land et a1.

2,745,134 5/1956 Collins l81 2,895,165 7/1959 Fry 181 WILLIAM J. STEPHENSON, Primary Examiner.

Claims

1. A LONGITUDINAL WEB STRETCHING MACHINE COMPRISING, DRAW ROLL MEANS, FEED ROLL MEANS, SAID DRAW AND FEED ROLL MEANS BEING ARRANGED TO HAVE A CONTINUOUS WEB PASS THEREBETWEEN, MEANS FOR ROTATING SAID DRAW AND FEED ROLL MEANS TO ADVANCE THE WEB PASSING THEREBETWEEN, AND MEANS FOR PIVOTING SAID DRAW ROLL MEANS RELATIVE TO SAID FEED ROLL MEANS TO THEREBY VARY THE DISTANCE BETWEEN SAID DRAW AND FEED ROLL MEANS.