CA2002894C - High speed contact sealer - Google Patents

Abstract

Apparatus for the high speed manufacture of elongated tubular film products from lengths of flexible, flat films. Film is unspooled, passed over a forming collar, and onto a tube. On the tube, the film has a circular cross-section, with overlapped edges. A
sizing ring correctly sizes the overlap. The film is immediately fed into a heating unit, where a closed-loop band contacts the overlap and heats the film to form a sealed seam. The film is advanced through the heating unit by boggie mounted drive belts. From the heating unit, the film is advanced into accumulation adjacent a casing brake.

Description

200289~

HIGH SPEED CONTACT SEALER

BACKGROUND OF THE INVENTION
This invention relates to apparatus for the manufacture of elongated tubular film products from length of flexible, flat films, and more particularly, to a high speed contact sealer.
Consumer products such as meat products and especially sausage are formed in elongated, closed end tubes known as chubs. Chubs and similar containers have been formed serially from filled, elongated tubes of film. The elongated tubes of film have been formed by machinery from rolled lengths of flexible, flat film. Such machinery of the past has been valuable, but limited in high speed capacity.
Known machines for manufacturing closed film product from flat film include intermittent heating units such that flat film ls formed over a formlng shoulder lnto rolled film having an overlapping seam, which rolled film ls then paused in its movement. With the fllm paused, a heatlng bar ls brought to bear against the seam of the film. The heating bar seals the seam. After such heating, the film is advanced to a distance such that a next section of unsealed film is available for heating again.

SUMMARY OF INVENTION
In a principal aspect, the present invention constltutes improved apparatus for the manufacture of a length of closed fllm product form a length of flexlble, flat fllm comprlslng, in combination: (a) a support frame; (b) a form member supported at one end by the frame and extendlng as a cantllever beam, generally horlzontally, and deflnlng an axls;
~c) a fllm form collar surroundlng the form member, sald fllm form collar constructed to fold the sldes of a flat strlp of fllm one over the other to thereby deflne a seam of a closed fllm product, surrounding the form member; (d) means mounted on the frame, for transportlng the closed fllm product axially on the form member, sald means for transportlng comprlslng flrst and second transport members posltloned on opposlte sldes of the form member and contlnuously frlctlonally engageable wlth film on the member and movable to transport the film therewith axially on the form member, and sald means for transportlng further comprlslng means for synchronously driving the first and second transporting means; and (e) heat seal means mounted on the frame and lncluding a solid, closed loop, movlng band posltlonable over the seam to engage the seam for heat and pressure transfer to the fllm, sald heat seal means further comprlslng means for drlvlng the movable band ln synchronlzation wlth the flrst and second transport means for slmultaneous movement of the seam wlth the film on the form member; (f) means for posltlonlng the closed loop, movable band over the seam to engage the seam; the flrst and second transport members belng posltloned axlally ln posltlons substantlally axially centered on the closed loop, moving band of the heat seal means.

- 2a -A principal obiect of the invention ls an apparatus capable of speed not previously achieved and including 500 feet per mlnute of product.
These and other objects, aspects and advantages of the invention will be described in relation to the preferred embodiments of the lnventlon, under the heading Detailed Descriptlon Of The Preferred Embodlments, as follows.

BRIEF DESCRIPTION OF THE DRAWINGS
In the followlng Detailed Descriptlon of the Preferred Embodlments, two preferred embodlments of the inventlon are described. These two embodiments are depicted in the accompanylng drawlng, the flgures of whlch are each as follows FIG. 1 is a side elevation view of the apparatus of the first preferred embodiment;
FIG. 2 ls a plan vlew of the apparatus of the flrst preferred embodiment;
FIG. 3 ls an exlt-end elevatlon view of the apparatus of the first preferred embodiment;

~ zoo~

FIG. 4 ia a schematic, perspective view of the apparatus of the rirst preferred embodiment;
FIG. 5 is a view of the product formed from the film handled by the apparatus of the fir~t preferred s embodiment;
FIG. 6 i8 a cross-section of the product of FIG.
5, excluding contents, ~howing the ~eam sealed by the apparatus;
FIG. 7 is an exploded per~pective view of a form-tube-to-fill-tube ~olnt of the apparatus of the rirst preferred embodiment;
FIG. 8 i8 a cross-section Or a film tension regulator of the ~irst pre~erred embodiment, the cross-section being taken along line 8-8 in Figure 9;
FIG. 9 i8 a perspective view of the film tension regulator of the first preferred embodiment;
FIG. 10 is a collection Or three schematics view of a flag and an eye mark employed in the first preferred embodiment to synchronize the first preferred embodiment with a rotary stuffing machine used in a~sociation with the ~irst preferred embodiment, with the flag and mark in condition Or ~ynchronization at the top of Figure 10, with the flag and mark in condition reguiring less drag from the film tension regulator of Figure~ 8 and 9 in the middle of Figure 10, and with the flag and mark in condition requiring more drag at the bottom of Figure 10;
FIG. 11 is a partial perspective view of the ~ore tube, heat ~ealing unit and transport mechanism of the first preferred embodiment;
FIG. 12 is a partial perspective view of the heat sealing unit, transport mechanism, and film advancing mechanism of the first preferred embodiment;

Z00~8~

FIG. 13 ia a ~ide elevation view, similar to Flgur- 1, of the ~ d and more preferred embodiment ot the invention;
FIG. 14 i8 a broken, partially cross-sectioned view of the ~upport ~tructure of the heat sealing unit of the ~econd preferred embodiment;
FIG. 15 1~ a partial, ~ldo elevation view of a spring-loaded bearing bloc~ of the heat sealing unit of the second preferred embodiment;
FIG. 16 i8 a cross-sectional view of film about the form tube of the s~:~n~ preferred embodiment;
FIG. 17 i8 an exploded perspective view of a form-tube-to-fill-tube ~oint of the ~econd preferred embodiment of the invention, similar to Figure 7;
FIG. 18 i8 a cross-section of a film tension regulator of the ~econ~ preferred embodiment, similar to Figure 9;
FIG. 19 is a side elevation view of an inner ring of the film tension regulator of the second preferred embodiment;
FIG. 20 is an end elevation view of the inner ring of Figure 19;
FIG. 21 i~ a cro~s-section view of a closed-loop belt of the film advancing mechanism of the second preferred embodiment of the invention, depicting the ~hape of the preferred shirring finger of the belt;
FIG. 22 is a perspective, detail view of an idler roller ad~ustment of the first and second pr-ferred embodiments, and a dot scanner of the second preferred embodiment of the invention;
FIG. 23 i5 a perspective, detail view of a plate-locating pin and toggle clamp as~ociated with a plate 26 of the first preferred embodiment and the second preferred embodiment;

20028~4 FIG. 24 is a broken, end view of a film loading and ad~ustment mechanism of the second preferred embodiment; and FIG. 25 is a broken, side view of the mechanism of Flgure 24.

DETATT~n n~-CCRIPTION OF THE ~ ~KK~U EMBODIMENT
Referring to Figure 1, the first preferred embodiment of the invention i~ one form of an improved apparatus 10 for the manufacture of a length of closed film product from a length of flexible, flat film 13.
The apparatus comprises, in combination, (a) a support frame 12, (b) a form member 14 supported at one end by the frame 12 and extending as a cantilever beam, generally horizontally, and defining an axis 15; (c) a film form collar 16 ~urrounding a section of the form member 14, said film form collar 16 constructed to fold the sides of the flat strip of film 13 one over the other around the form member 14; (d) a transport mechanism 18, mounted on the frame 12, for transporting the closed film product axially along the form member 14; and (e) a h-at seal mechanism 20 mounted on the frame 12 and positionable over the seam to engage the seam for heat and pressure transfer to the film 13 and simultaneous movement of the seam with the film 13 on the form member 14.
A chuck 21 holds in cantilever fashion, and in cG.._entric fashion, a meat product di~charge horn 23 and opposite thereto, the form member 14 in the form of a forming tube. The chuck 21 includes a quick release mechani~m 24 for rapid opening of the chuck, and ther~by, change~ of the horn 23, the forming tube 14, or both.
Ad~acent the chuck 21, the film form collar, or "forming" collar 16 is held by a plate 26 and forms Z00~8~

fl-xible, flat film 13 around the form member 14. The forming collar 16 i8 arranged horizontally to receive flexible, flat film 13 and form the film 13 so that the film 13 exits the collar wrapped about the form member 14, horizontally. The formed film 11 (see FIG.
6) i9 in the shape of a continuous cylinder, with one longitudinal side of the film overlapped over the other side of the film to define a seam 17.
The plate 26 i~ accurately machined and nests on a set of locator pins mounted on plate supporting brackets 29, such as pin 27 in Figure 23. The locator pins are located about the brackets to abut points along the periphery of the plate and provide for concentric alignment of the forming collar or "~houlder" 16 with the forming tube 14. The locator pin~ are ne~ting pin~ and the plate nest~ again~t the pin~. B~cause of the ne~ting, the plate automatically and naturally comes to rest in a concentric position.
Release features are as~ociated with the plate 26 which support the forming collar 16. The release features allow for quick changes of the forming collar 16 to adapt to films of different size~. Toggle clamps 28 (~ee FIG. 2 and FIG. 23) mounted on the plate supporting brack-t provide the quick release of the collar 16.
An idler roller 30 below the plate 26 allows the ad~ustment of film tension on the forming shoulder 16.
Uniform tension and forming is maintained. Tension is a matter of the stiffnQss of the particular film in use. The idler roller 30 is located vertically beneath the form fill shoulder 16 on ad~usting brackets such as bracket 31 (cee FIG. 22) on the plate supporting brackets 29 of the support frame.
Ad~ustment is vertical, through manual loosening of bracket fasteners such as machine bolts, manual Z0028~4 v-rtical positioning of the ad~usting brackets and manual re-tightening of the fasteners. The ad~u~ting brackets ars keyed to maintain vertical alignment so that the axis of the idler roller 30 is always parallel to the incoming surfaco of the forming shoulder 16.
After film 13 passes through the forming shoulder or collar 16, lt continue~ on the form fill tube in the region of contact heat sealing. A pair of drive belts 40, 42 (FIG. 4) are positioned on opposite sides of the tube along the longitudinal axis of the tube. The drive belt~ draw the film forward along the forming tube. The belts propel the film forward by maintaining pre6sure contact on two ad~acent surfaces on opposite sides of the film along the forming tube.
Floatable carriage arrangements such as 43 having spring pressure maintain pressure uniformly along the length based upon initial pressure pre~et in the device.
The belts 40, 42 are not heated. The film is engaged by friction of the rubber belt material against the film. The belts are of ~light sponge nature to conform to the shape of the forming tube. Opposed drive belts are considered necessary to prevent film skewing and improve film uniformity of tension. The belts are driven through a drive shaft from below through gear boxes and pulleys. A single mechanical drive shaft drives both belts through the gear boxes and drive pullefs. Single drive synchronizes the b-lts. The belts are timing belts which prevent slippage and continue complete control over the longitudinal speed of the film as it pA~eE through the region of the forming tube.
A heating unit 50 include~ a continuous closed-loop band wrapped about two spaced pulleys 52, 54. The lower surface of the belt, when placed in contact with ~002894 th- seam of the film, transfers heat to the seam, thereby ~ealing the seam. The belt, two-spaced drive pulley~ and heating unit therebetween are mounted above the form filled tube in the heat sealing region. The mounting i8 pivotal and provides for plaeement of the lower surface Or the belt on the seam through pivoting of the heating unit downward, and retraction of the unit upward, under machine control.
A polytetrafluoroethylene (PTFE, trademark TeflonR) cover 60 (FIG. 7) i8 placed on the form filled tube beneath the film in the heat sealing area. The PTFE cover surrounds the entire cireumference of the form filled tube. The PTFE cover extends along the form filled tube a length equal to the complete length of the heat sealing unit.
Beneath the PTFE cover i8 a silicon padding 70.
The pad provides for slight deformation of the film under the pressure of the heat sealing unit. The pressure and slight deformity creates an area of surface contact, as opposed to line contact, of the heat sealing belt against the film seam. The heat sealing belt is flat. The belt would normally come in line eontact with the rounded tub~, but for the pad 70.
Line contact would result. The silicon, spongy material is in a ~trip along the forming tube and does not extend eireumferentially fully about the tube. The deformation of the silicon strip converts the otherwise line eontaet of the flat heat sealing belt against the round tube to surface contact of the flat belt to a flattened portion of the silieon pad and PTFE cover about the tube. In addition to providing surface eontaet of the tape against the film, the silicon pres~ure pad distributes pressure and eliminates non-uniformitiec of mechanical component~.

Z002(~
g The closed-loop heat sealing belt i8 heated.
Ths belt moves in synchronization with the drive belts.
A ~-t of heaters are contained within the framework of the heating unit. The heaters extend the entire length of the framework, and are electric resistance heaters.
The entire ma~s of the framework is heated. The mass, in turn, through contact with the belt, heats the belt.
Heat is transferred from the belt to the film.
The belt is a ~tainless steel band, PTFE coated on the outside. The thickness of the belt and the radius of the pulley~ of the heating unit are interdependent, for maximum life of the belt, due to the criticality of pulling stress, bending stress and temperature effect~. The following eguation yields pulley diameter if belt thickness i~ pre-selected, or yield~ belt thickness if the pulley diameter is pre-chosen.

/3 1-5 ~33btHD/V~aX) (1 - v~)(Dmin) 20 which Tf - temperature factor Sy - yield ~tress of the belt material at room temperature, p~i t - thickness of metal belt, inch Hp - horsepower to drive metal belt Vmax ~ maximum liner velocity of belt ft/min E - modulus of elasticity psi Dmin ~ smallest pulley diameter inch b - width of metal belt v - poisson's ratio This equation offers 106 - 107 cycle life time for most metal belt materials and the fatigue life of 200289~

the belt is guite suitable for the application of the eontaet sealer.
The preferred heat sealing unit with a sealing ability up to 500 feet/minute needs approximately 1/5 driving horse power, and belt width of .25" for general packaging. With ~ueh parameters, the equation simplifies as follows:

Sy- Tf/3 - t (1 ~ V~)(Dmin) For 301 high speed yield stainless steel, the following parameters have the following values:

Sy ~ 260 k~i Tf - .86 v - .3 E - 26 x 106 psi The material of the metal belt ean be changed to others such as 17-7 pH stainless steel, beryllium copper, 304 cold rolled stainless steel and the like, but for 301 high speed yield stainless steel, the relationship of pulley diameter and belt thickness is as follows:

Sy- Tf/3 - 74533 ' 90t78 + 28.57 x 106t Dmin ' 28 57 x 106t2 inch 200Z89~

D I A . I~CIl ~1. S ' 30~ ~l/CI~ Y~-0 Sr~NL~SS sr~L/
.0- /
.S
3.0

2.S' 2.0~

2 3 4 5 c 7 o~ 9 /o BEL T T~lC~ SS /~ I~IL .

The flexible, flat film 13, when heat sealed, absorb~ heat energy at a specific rate dependent upon its materials. The film also requires a specific amount of pres6urQ during fusing, also dependent upon its materials. From these properties and from the setting of a desired film speed, the length of the heating unit i~ determined. The length of the heat seal unit of the preferred embodiment is approximately twenty inches, and the speed capability of the unit, as intended, is approximately 500 feet per minute.
In contrast with prior art devices, the heat sealing unit of the invention and especially the preferred embodiment transfers heat to the film continuously, continuously sealing the seam of the film. Intermittent operation is not required, and is avoided .
The pressure by which the closed-loop tape is brought to bear against the film and the underlying PTFE coating and silicon strip is determined by a pneumatic cylinder. The pressure applied by the cylinder is adjustable. Once a specific film is placed ~ Z00289~

for operation in th- machine, a constant pressure is maintained. Ad~ustment is made only from film to film.
The amount of force to be brought to bear against the film is directly determined by the film type, and is available as a recommendation of the film manufacturer.
The pulleys of the heating unit are driven by a drive arrangement on the discharge end of the heating unit. A timing belt is driven by the same driving mechanism as drives the drive belts. The heat sealing unit and the drive belts are synchronistically driven for uniformity of speed of the drive belts and the heat sealing tape. The heat sealing unit and the drive belts are independently clutched, to provide for setup of the machinery. In setup, the drive belts are placed and film propelled along the forming tube. The heat sealing unit is then brought to bear.
The film 13 has a tendency to shrink under heating. The pressure of the heat sealing tape against the seam prevents shrinkage in the area of the seam.
The film draws tightly about the tube. The forming tube i8 sized to accommodate the shrinkage.
Because of the length of the heating unit and the fact that it is heated, the heating unit has a tendency to eYp~n~ longitudinally during operation.
Accommodation of expansion is provided in the mounting of the heat sealing unit at its input end.
Accommodation is provided by a mounting which allows the heat sealing unit and the mounting member attached thereto to slide longitudinally along a cooperating mounting member. Binding and buckling is prevented.
Mounting of a bracket attached to the heat sealing unit along a longitudinally aligned pin is one possible form of such a mounting.

Z002~39~

As most preforrQd, the heating unit includes four embedded heaters. Heated material coats the interface between the heaters and the heating unit mass, to prevent oxidation and maintain the level of heat energy reguired to sufficiently heat the heat unit. All four heaters are provided electricity through one circuit and temperature is controlled through one thermocouplQ. Thermal mass of the heater i8 chosen for thermal inertia such that control variations in the apparatus are compensated as to the seal of the seam by the thermal inertia of the heating unit. Sealing i~ maintained despite such control variations. Additionally, in sQtup, the he~ting unit is preheated. When first brought to bear against the fllm the heating unit loses heat energy. The inertia of the heating unit allows the control circuitry of the heating unit to add heat energy to the heating unit sufficient to compensate for the initially lost heat energy before so much heat energy i5 lost that the seal of the seam i~ also lo~t.
A collar 80 interposes a fill pipe 90 and the form tube. The fill pipe extend~ coaxially from the form tube. The collar is split for placement about the fill tube. The collar centers the fill tube with the form tube. A plurality of openings are spaced circumfarentially about the collar, and provide air passage from the atmosphere to within the form tube.
Air pressure is equalized on both sides of the collar to prevent a vacuum effect inhibiting forward motion of the film as it leaves the form tube.
A casing brake mechanism (not shown) is adjacent the remote end of the fill tube.
Between the heat sealing region of the form tube and the casing brake, and along the fill tube, a film advancing mechanism 100 includes two opposed, closed-~ 2002894 loop belts 102, 104 having shirring fingers such as 108 foroed thereon. The transport mechanism (i.e., the b-lt~ 40, 42) advances closed, sealed film from the heat sealing region, and a~sures no back flow of film into the heat sealing region. The ~hirring fingers are flexible, and in positions of interference with the fill tube. The shirring fingers sweep film along the fill tube and allow the film to accumulate ad~acent the casing brake for allowing the seal area to cool. The two belts of the advancing r~ch~n~sm are synchronously driven with the drive unit of the apparatus and the heat sealing unit thereof. The shirring fingers, or paddle blades, extend outwardly relative to the belts, and are paired from belt to belt to be slightly staggQred in relationship to each other as they advance film along the fill tube. The belt~ are driven about pulleys, the outer periphery of which are textured for positive driving contact against the belts. Slippage is prevented. A random stagger of the shirring fingers is sufficient. The belts and pulleys Or the advancing mechanism are po~itioned closely ad~acent the heat sealing unit.
A supply of flat film 13 i8 rolled on a mandrel 110 (FIG. 4) below the heat sealing unit. The mandrel or spool upon which the roll is placed is not driven, but is braked to allow for the prevention o~ overspin upon termination of machine operation. All driving of th- film is under power of the driving units adjacent the heat sealing unit. The mandrel is expandable to lock the film roll to the mandrel shaft. Gross lateral alignment of the film on the shaft is provided by the manual placement and locking of the film on the shaft.
The film passes from the mandrel over an idler bar for tension, then to an ad~ustable roller, which provides for ad~ustment of tension of the film. The film as rolled i8 not neeessarily uniformly tensioned, and ad~ustment for tension for uniformity is desirable.
Laek of uniformity will skew the film. The ad~ustable roller is a skewing roller, ad~ustable vertically about a pivot to ad~ust tension laterally. The film continues over another fixed roller and then upward into the tensioning roller previously mentioned in assoeiation with the forming eollar.
The earriage assembly 120 (see FIGS. 1, 2) for the drive belts 40, 42 is aligned about the axis of the form tube. An ad~u~ting nut allows eentering of the carriage assembly relative to the axis. A hand crank which rotates opposed lead serews then provides movement of both drive units simultaneously inward and outward relative to the form tube. Ad~ustment of tension of the belt on the film against the form tube is provided. Thus, both centering and drive pressure ad~ustmQnt are provided.
The apparatus of the invention is employed with a rotary platform maehine including a plurality of clippers which rotate past the elosed, tubular film exiting the apparatus of the invention, and form chubs from the film and pumped internal material.
Registration and tensioning of film with the elippers is provided by a film tension regulator as in Figures 8 and 9. The distanee between elippers is set slightly longer than the desired length of the elosed film, the l-ngth preferably being indieated by registration marks 202 (Figure 11) at regular intervals on the film.
Outside the filling horn i9 a PTFE ring 204 (Figure 8).
The outside diameter of the ring 204 i5 always less than the fin~shed tube diameter (85 to 98 percent).
About the outside circumference of the Teflon ring is a housing eontaining an O-ring 206 in a eaptive area.
About the out~ide of the captive area i~ an enlarged, annular chamber. Air supplies are connected to the chamber at several locations. The inside diameter of the O-ring and ad~acent housing assembly inner, annular edge i~ alway~ larger than 100 percent of finished tube diameter. As the film passes through the space between the ring 204 and the o-ring, a sensing circuit determines when film i~ not on registration with the clipper. An air pre~sure is supplied to the chamber behind the 0-ring through a pneumatic circuit, pressurizing the outside of the O-ring and displacing it inwardly toward the film and ring. A compressive force is applied to the film by pinching it to the ring. By controlling the time of the compressive force, stretch of the film is controlled. A feedback circuit of the machinQ including a sen~or 210 (Figure 8) and a sensor on the rotary machine (not shown) monitors the position of the clippere in space relative to the flow of film into the rotary machine. If an indicator mark on the film "reads" as it passes the tensioning devico in synchronization with a flag on the machine, then the film and clippers are in correct relation~hip. The flag on the machine is indicated by "CNT Flag" in Figure 10. A correct case is indicated at the top. A case of clipper lateness relative to the film iB indicated in the middle of the figure. A case of clippers being early is indicated at the bottom.
With a late clipper, tension on the film is reduced.
With an early clipper, tension is increased.
Referring to Figure 13, the second and more preferred embodiment of the invention is another form of an improved apparatus 210 for the manufacture of a length of closed film product from a length of flexible, flat film 13. As with the first preferred apparatu~ 10, the apparatus 210 includes a support frame 12, a form member 14; defining an axis 15, a form eollar 16, and a transport meehanism 18. The frame 12, m~iber 14, eollar 16 and mechAn~sm 18 of the apparatus 210 are substantially identieal to like numbered eomponents of the apparatus 10.
The apparatus 210 differs from the apparatus 10 in sQveral partieular~. First, a film loading and ad~ustment mechanism 130 provide~ ~or advantageous loading and ad~ustment o~ the film spool. A loc~ing hub (not shown) is loeated on a mandrel 110 for loeking the film spool on the mandrel. The hub includes three eccentric member~ spaeed equally about the hub which extend outward radially from the hub a~ the spool rotates, to contact the spool core and wedge lock it into position. Referring to Figures 24 and 25, a cantilevered loading and adjustment support bracket 132 extends horizontally from the frame 12, transversely to the form tube axis 15. The bracket 132 supports a similarly extending film guide assembly 133, including a pair of horizontally spaced guide arms such as arm 134 mounted along a film guide sleeve 135. The guide arms are ad~ustably movable along the sleeve for increasing and decreasing the distance between the arms, to accommodate wider and narrower film spools.
The guide arms are also releasably swung upward (not shown), away from the film spool for ease of mounting of the spool on the mandrel 110. The sleeve is laterally movable a]ong the assembly for ad~usting the lateral or transvarse loeation of the eenterline of spools.
The guide arms are ad~ustably movable and releasably ~wung by manual release of split, clamping ends 136 of the arms via handwheels 137, whieh drive clamping screws such as screw 138; manual movement of the arms; and manual re-tightening of the split clamping ends via the handwheels. The sleeve 135 is lat-rally movable under action of internal screw thread~ mating with external threads on a rotatable, laterally fixed rod 139. Rotation of the rod 139 via a handwheel 140 cause~ lateral movement of the sleeve.
Film guide roller~ 141 on cantilevered ends of the arms ride the edge~ of the film core, after the film spool is placed and the arms located about the spool.
A variety of film paths are available in threading of the film on the apparatus 210.
Additional roller~ are mounted by bracket beneath the carriage assembly 120 for greater variation of threading. Additionally, a pivotable film fQstoon 142 includes rollers mounted on cantilevered festoon arms 144. The motion of the festoon i~ damped by a pneumatic damper 146. As the apparatus 210 begin~
operation, the fe~toon rises to accommodate a lag in the speed of the ~pool relative to the speQd of the film under action of the tran~port mechAnism. As speeds match between the fllm at the transport mechanism and exiting the spool, the festoon lowers.
Referring to Figure 16, the forming tube 227 of the second preferred embodiment has an outer diameter slightly undersized (exaggerated in Figure 16 for clarity) relative to the diameter to which the film is to be formed. Opposed flats are located on the forming tube 227, for improved contact by the drive belts of the transport mech~nism. The flats are PTFE
coated. In an arc adjacent the band of the heating unit, the forming tube is not undersized.
As the film moves onto the forming tube, after leaving the forming collar, the film edges overlap a greater distance than ultimately desired. To size the film, the film is passed over a sizing ring, of ceramic, which has the diameter desired for the film.
The sizing ring is juxtaposed immediately adjacent the 2()02894 eontact point of the band of the heating unit, such that immediately upon sizing of the fiim, the film overlap is under pressure of the band, and bogins to seal.
In tho aroa of the heat soal meehanism 220 of the seeond preferred apparatu~ 210, and referring to Figures 13 and 14, the heating unit 50 i~ mounted via a slide mechA~ism 212 for linear, vertieal movement betwoen po~itions of operation and retraction. When in operation, the heating unit has its closed-loop band in contact with the seam of film pa~sing along the form ~ilm tube. Vertical slidQ guide rods such as 214 extend from a plate 215 through a guido block 216. The rods are slidable in th- bIock 216 and fastened to the plate 215. The plate 215 is fixed to the hoating unit 250, the guide block 216 i8 rixed to a mounting bracket 213 to the frame 12, and under action of a vertically acting slide cylinder 217, the rods, plate and heating unit are driven vertieally upward and downward under command of the apparatus control while~ the guide block 216 remains stationary. An end stop ad~ustment 218 provides for ad~ustment of tho torminal downward position of tho hoating unit 250, to accommodate variou~ film thickne~ses. The ond stop ad~ustment is comprised of a threaded column faatened to the plate 215, pA~e~ loosely through an ad~ustment bloek 219 on the guide bloek 216, and mounted by a pair of v-rtically ad~ustable locking nuts. A pin-and-slot parallol ad~ustmQnt between the heating unit 250 and slide mQchanism 212 provides for parallel ad~ustment of the heating unit 250 relative to the form member 14.
In the heating unit 250, as in the heating unit 50 of the apparatus 10, a continuous closed-loop band or belt is wrapped about two spaced pulleys 52, 54. In the unit 250, phenolic disks are mounted to the baek~idQs of the pullQys to insulatQ the pulley drive m-chanism from h~at of the band transmittQd to the pull-y~. Th- drive pulley 221, ~hown in Figure 12, i8 a glass reinforeed LQxanR pulley which insulatQs from h~at of the band transferred along th~ drive shaft.
RefQrring to Figure 15, thQ idler pulley 54 in the unit 250 is mounted to a spring-loaded bearing block 223. The bloek spring-biases the idler pulley 54 to tighten the closQd-loop band, and is movable by spring tQnsion, and by band tQnsion against 6pring ten~ion, to maintain con~tant band ten~ion while the band undergoQs temperature variations.
The hQating unit 250 includQs a central, stainlQss st~el bloek 225, aa in Figure 15.
Electrieal rQsistanee h~aters are loeated within the bloek 225, and brought into eontaet with the block by heat ~ink compound. The exterior of the block 225 includes lateral heat shields, and a peripheral band contaet faee whieh i~ nickel plated, PTFE impregnated, and polishQd. The band is also PTFE eo~ted for eontact with thQ band eontaet face. This combination of matQrials provide~ for a lubricated contact of the band with th~ band eontaet faee.
ThQ band eontaet faee has a width not greater than the width of the band eontaet faee, and the face i- di~tane~d from the eQntral portion of the bloek 225 bu a narrow-noekQd faee ~upport seetion. If film blllows, at the sides of the moving band, the film doQs not eontaet the bloek 225 due to the narrow-necked fae~ support sQetion. This absenee of contact avoids random heating and tearing of the film.
Ad~aeent the forming tube to fill tube union, the forming tube is cutaway, as at loeation 229 in Figure 17. The cutaway foreshortens the forming tube relative to the heating unit, which has been found to 2C~2~9~

obvlate drag of the fllm on the formlng tube, and ellmlnatlng skewlng of the fllm.
Static electrlclty between the lnner surface of the movlng fllm and the PTFE coated formlng tube ls ellmlnated as follows. Copper, conductlve staples are located along the formlng tube, wlth crowns of the staples exposed along the exterlor of the formlng tube. The legs of the staples extend through the TeflonR coatlng, lnto contact wlth the metal tube ltself. The tube ls grounded to the frame of the machlnery.
Standard englneerlng technlques are applled to other sources of statlc electrlclty.
As ln Flgures 18-20, the PTFE rlng 324 of the fllm tenslon regulator of the second preferred embodlment lncludes a ramped portlon 326. The portlon 326 provldes for a smooth transltlon of fllm off the flll tube and over the PTFE rlng.
The fllm tenslon regulator of each embodlment of the lnventlon accompllshes reglstratlon of the fllm exltlng the embodlment wlth a rotary platform machlne. A representatlve rotary platform machlne ls dlsclosed ln U.S. Patent No.
4,821,485.
Speeds of the selected embodlment of the lnventlon and the accompanylng rotary machlne are matched by a controller whlch takes lnput from a sensor 328 and a sensor on the rotary platform machlne. The sensor 328 recognlzes an eye mark on the fllm as the eye mark passes the sensor. A slgnal ls sent as each eye mark passes, and the controller malntalns a count of the slgnals. The sensor of the rotary .- f~
~ 61368-855 .

2002g~4 - 21a -platform machine ls also statlonary, and recognlzes flags on the machlne as they pass. A slgnal ls sent and a count malntained. The two counts are compared, and any '- -' li ,~

dlrr-rence cau~-- an increase or decrea6e in speed of th- lnvented device Thus, the rotary machine is the ma~ter, and the invented device is the slave Two prererred ~mbodiments of the invention are now described To particularly point out and distinctly claim the sub~ect matter regarded as invention, the ~ollowing claims conclude this specification

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. Improved apparatus for the manufacture of a length of closed film product form a length of flexible, flat film comprising, in combination:
(a) a support frame;
(b) a form member supported at one end by the frame and extending as a cantilever beam, generally horizontally, and defining an axis;
(c) a film form collar surrounding the form member, said film form collar constructed to fold the sides of a flat strip of film one over the other to thereby define a seam of a closed film product, surrounding the form member;
(d) means mounted on the frame, for transporting the closed film product axially on the form member, said means for transporting comprising first and second transport members positioned on opposite sides of the form member and continuously frictionally engageable with film on the member and movable to transport the film therewith axially on the form member, and said means for transporting further comprising means for synchronously driving the first and second transporting means; and (e) heat seal means mounted on the frame and including a solid, closed loop, moving band positionable over the seam to engage the seam for heat and pressure transfer to the film, said heat seal means further comprising means for driving the movable band in synchronization with the first and second transport means for simultaneous movement of the seam with the film on the form member;
(f) means for positioning the closed loop, movable band over the seam to engage the seam; the first and second transport members being positioned axially in positions substantially axially centered on the closed loop, moving band of the heat seal means.

2. Improved apparatus for the manufacture of a length of closed film product from a length of flexible, flat film, as in claim 1, in combination with the means for engaging the formed film at the discharge end of the form member for removing the film from the form member.

3. Improved apparatus for the manufacture of a length of closed film product from a length of flexible, flat film, as in claim 1, in combination with a film closure device.

4. Improved apparatus for the manufacture of a length closed film product from a length of flexible, flat film as in claim 1, in combination with a closure device and means for advancing formed film through the closure device.

5. Improved apparatus for the manufacture of a length of closed film product from a length of flexible, flat film as in claim 1, in combination with a closure device and means for advancing formed film through the closure device and further with film restraining means.

6. Improved apparatus for the manufacture of a length of closed film product from a length of flexible, flat film as in claim 1, in combination with a generally concentric product fill tube extending axially in the form member.

7. Improved apparatus for the manufacture of a length of closed film product from a length of flexible, flat film as in claim 1, in which a cantilever mounted chuck with release capability cantilever mounts the form member.

8. Improved apparatus for the manufacture of a length of closed film product from a length of flexible, flat film, as in claim 1, further comprising a spacer collar, the spacer collar providing air flow into the form member.

9. Improved apparatus for the manufacture of a length of closed film product from a length of flexible, flat film, as in claim 1, in which the form member is PTFE coated.

10. Improved apparatus for the manufacture of a length of closed film product from a length of flexible, flat film, as in claim 1, in which the form member includes an axial strip of compressible material at an elongated sealing junction.