CA1128413A - Automatic high-speed wrapping machine - Google Patents

Abstract

AUTOMATIC HIGH-SPEED WRAPPING MACHINE

ABSTRACT
An automatic high-speed wrapping machine for wrapping packages in heat sealable thermoplastic film is disclosed wherein the film seal at the side and ends of the packages is made at a high rate of speed as the packages travel through the machine.
The packages travel continuously in a straight line through the machine and are delivered at the input end of the machine by a flighted infeed conveyor into a film inverting head where the packages are surrounded by the film, thence to the side sealing mechanism which forms a seal while severing the selvage from the packages, then into an end sealing mechanism where both ends of the packages are sealed and the film web connecting succeeding packages is severed. The machine produces packages which have a sealed film wrap around the entire package which is then in con-dition for subsequent shrinking of the film if desired to pro-vide a package having a tight film overwrap.

Description

1~28~

Thls is a division of copending Canadian Pat~nt Appli-cation Serial No. 312,860, filed on October 6, 1978 and assigned to the present assignee.
B~CKGROUND OF T~IE INVENTION
This invention relates to automatic package wrapping apparatus and in particular to apparatus which wraps the product in heat sealable thermoplastic film and seals the edges of the film to totally encase a product within the film where the package moves continuously at a high rate of speed through the machine.
The prior art discloses apparatus for wrapping packages in thermoplastic film in which the packages move intermittently as does the plastic film in which they are to be wrapped. The intermittent movement of the packages through the apparatus occurs because it is necessary to stop the packages during the sealing operation where the sealer is stationary. Some of these ; machines are known as L-sealers because they form "trim seals"
in the shape of an "L" utilizing a web of centerfolded film.
The "trim seals" were formed by clamping the top and bottom webs of the folded-film between a padded bottom jaw and a top jaw containing a narrow heating element which formed a neat weld bead (i.e., ~'trim seal") of melted film while severing the film containing the product from the adjacent portion of the film. Thus one of the valuable features of L-sealers is that the packages they make are neat and attractive having neat "trim seals" on three sides and clear film on the fourth side and top and bottom.
More recent machines have utilized a continuous longi-tudinal sealer and an end sealer which moves at approximately the velocity of the packages as they travel through the machine so that it is not necessary to stop the packages while performing the end sealing operation. Such prior art machines have generally been of three types. One type had a continuous ultrasonic side .

ji/ ' ~ .

~12B4.1~3 sealer and a complex series oE multiple flighted end sealing jaws which were spaced for a particular product. This type required substantial set-up time for change in length of product to be wrapped. A second machine of this type, while making packages similar to those produced on an L-sealer worked by drawing film off a roll under tension, folding it around the product, drawing it past a hot knife side sealing mechanism under continuous tension by means of a conveyor belt and an overhead pressure belt located downstream of the sealing mechanism, and then formed the end seal with a moving end sealer. A disadvantage of this type of machine is that it is not capable of making satisfactory seals on all commercially available heat sealable thermoplastic ~ilms.
A further disadvantage involves the overhead pressure belt which precludes its use on fragile or delicate products.
A third type had an overlapped longitudinal seal on the top or bottom of the packages wrapped. Since the overlap not only ran along the bottom of the packages but also ran halfway up both ends the packages lacked the neat appearance and hence the sales appeal of the trim sealed packages as made on the L-sealers.
Since many of the products so wrapped are sold in self-service retail stores, the appearance of the package has an important effect on the sales of the product. An additional disadvantage of the overlapped seal is that the width of the web of film must be precisely correct, requiring an exact width film for each size of product.
An important disadvantage of all three types of machines is that the film must be under continual tension in order to track properly over to the forming heads on such machines, necissitating means for gripping the packages and/or the film to draw the film into the machine and over the head such as vacuum conveyor belts, pressure belts, and moving flighted end sealing mechanisms.

ij'/ .

`I f-, ,~ j, llZ8~3 l It is a primary ol)~c~ o~ this invention to provicle ~n auto-! matic hi~h-speed wra~pill~ n~ac}~ine in wllic:h the flow of packacJes tllrouqll the maclline is con(:inuous without need to stop while ¦ forming trim seals at one side and botll ends oL the packages.
It is a urther ob~ec~ to provicle a machi~ hich is capai)le j of handling both high and 1O~A~ profile packages and packages of variable length and width ~ith only relatively simplc adjustments when the package size is changed.
It is a further object to provide reliability and quality ~ in the packaginq of products.
; It is a further object to provide a machine ~hich is designed to resist jamming and to continue to function even though a pack-age or packages may be improperly located when end sealing is attempted so that the malfunction may be corrected without shut-lS ting down the assembly line.
It is a further object of this invention to provide a machine which is safe for operators and which does not crush packages in ` the case of the aforementioned malfunction.

i Another object is to provide a simple means of sealing ~he ?Q I free edges of a folded web of film together to form a tu~e surrounding products operable continuously without havin~ to stop the travel of the product.
It is a further object of this invention to provicle trim seals on three sides of the packages and clear (i.e., not over-lapped) film on the fourth side and top and bottom of the packageso that the final appearance of the package is identical to that produced on an L-sealer.

:~L28~
It is a feat~re of the machine that it can utilize all ~nown commercially use~ heat sealable thermop:Lastic films and achieve reliable end and side seals with the des:irable trim seal appearance.
~ nother feat~re of the invention is to provide a machine with film flow through the mac:hine sufficiently tension free so that film and product will flow withou-t any need for pressure gripping conveyors which can damage delicate products.
It is a feature of the machine to provide an infeed conveyor mechanism which has positive feed of the packages into the machine thereby causing the packages to be equally spaced thereby increasing the quality of the sealed packages.
Generally, the present invention provides an automatic film wrapping machine for wrapping products in heat sealabl~
thermoplastic film in which the flow of products through the machine is substantially continuous and in a straight line. The machine includes a film inverting head which receives packages at its input Erom an infeed conveyor and folded film from film supplying means. The inverting head inverts the film and envelops the packages in the film while the film is substantially tension free. A side sealing means is provided for continuously heat sealing the free edges of the folded film in proximity to the package, severing excess selvage from the package and drawing the film over the inverting head. ~eans is provided for removing the selvage of the film after the film has been sealed. An end sealing mechanism having sealing jaws receives at one end the side sealed packages and includes means for closing the sealing jaws on that portion of the film between the packages to simultaneously seal the ends of the packages and sever the film between successive packages at the seal. The sealing jaws move at approximately the same velocity and direc-tion as the film where the jaws are closed and in the opposite ws/ "~

8~13 direction to the film aEter the seal is made and the jaws are opened. The end seal mechanism has means to deliver the sealed packages to the output of the machine.
Other objects ancl features of this invention will become apparent from -the following description of the preEerred embodiment of -the invention when read in conjunc-tion with the figures in which:
Fig. 1 is a perspective view from the rear of the high-speed film wrapping machine of this invention with guards removea to expose the details.
Fig. 2 is a top view of the machine of Fig. 1 showing the packages as they travel through the machine and in addition showing a film folding mechanism.
Fig. 3 is a perspective view of the packages of Fig.

2 showing the state of the film sealing procedure of correspond-ing packages.

ws/'3-: . .

~ r~ ~
284:~3 Ficl. 4 is a s;de vic~l, part1nlly in cross-section, of ¦~the inf~ed conv~yor.
ll Fig. 5 is a p~rtial cut--away view of the chain drive of' I,ti~e infeed conveyor.
' Fig. 6 is a perC.pective vie~ of the side sealing mecha-¦¦nisnt.
Fiy. 7 is a cross-sectional view of the jaw portion of the side sealing mechanism.
FiCt. 8 is a perspective view of the end sealer mechanisn .
Fig. 9 is a schematic of the power kransmission mecha-nism of the entire machine.

DETAILED DESCRIPTION OF PREFERRED EMBO~IMENT

A perspective view of the automatic high-speed film packaging machine generally designated 10 of this invention is show~ in Fig. 1. Fig. l-shows sections of the machine generally designated including an infeed conveyor 20, a film dispenser 30, an inverting head section 40, a side sealer 50, an end sealer 60, and a control panel 80. Products to be wrapped in film enter the machine 10 via inreed conveyor 20. The conveyor 20 delivers the spaced-apart proclucts to the inverting head 40 section where a folded film from a roll of film in dispenser 30 surrounds the product. The folded film enveloping the product is sealed at its ¦loose edges by the side sealer 50 to form a tube of film enclosinct¦
~he spaced produc-ts. The selvage at the sealed edge is severed an~

¦removed. l`he Eilm between the products is sealed and severed at the end soaler 60 to proOuce individual seal~d packaqes ~ the product.

I ~ -7-!¦

~z~
The machine wraps a product in a flexible plas-tic film in which the t:ravel of the product througll the machine is in a straig}lt line and is ess~ntially continuous. The Eilm 31 is s~lpplied to the machine 10 as a folded web a-t right an~les to the direction 21 of Elow oE tlle product P (shown in Figs. ~ and

3) through the machine. The film 31 is provided to inverting head 40 where -the film is redirected and turned inside out to provide a film -travelin~ in the same dircction as the pac~ages delivered by the inEeed conveyor 20. A de-tailed description of the inverting head ana the manner in which it changes the direction of the film feed is contained in U.S. Patent No.
3,583,888 gran-ted to Shanklin ~esearch Corporation on June 8, lCJ71 .
The infeed conveyor 20 pushes products into the inverting head ~0 to cause then to be enclosed by the folded film supplied by film dispenser 30 on the top, bottom, and one side of the product with the other side of the product adjacent to the edges of the folded film. The product thus enclosed in the web of film travels with the film pas-t a side sealing mechanism 50 in Fig. 1 which seals the two free edges of the folded film together to ~orm a continuous tube of film which envelops the succession of products which are being fed in-to the machine by infeed conveyor 20. The side sealer also severs the excess width of film from the -tube and this selvage is removed by a vacuum source. As the product progresses further through -the machine 10, an end sealincJ mechanism, denoted gener-ally by the numeral 60, seals the trailing edge of each pacXage while simultaneously sealing the leading edge of the succeeding package in the machine and it also severs one packacJe from the other while the packacJes are traveling without stopping throu~Jh the maclline. The 8`
ws/ .

-. ~Z8~

end seal mech~nism ~n is so de~-iicJIled that it travels a short dis~ance witll ~he packac3e at su~stantiaLly the same velocity ¦ as the package while thc seal is being made. ~fter the seal ~las been made, the sealing ~lechanism releases from the ilm and returl-to its original positioll to repeat the transverse seal for the next package. The wrapped package may then be convcyed through a shrink tunnel 70, shown in phantom view in Fig; 1, if shrinkin~
¦¦ of the film around the package is desired.
i Because the package being wrapped in the film proceeds I through the machine 10 at a substantially uniform velocity, the machine is capable of operating at film web speeds as high as 120 feet per minute although 60 to 100 feet per minute is a more typical speed. The machine is capable of wrapping in excess of one package per s~cond. ~
Fig. 2 shows a top view of a packaging machine 10 which is essentially the same as that shown in perspective in Fig. 1.
The major component parts 20-70 of the machine 10 are shown in schematic form in Fi~. 2. In addition, packages Pl-P8 are shown as they pass through the machine.
The film feed mechanism 30' of the Fig. 2 differs from the fi~m feed 30 of Fig. 1 in that film feed 30' utilizes a roll of unfolded film 32 which is folded on folding mechanism 33 to produce a folded web 31 corresponding to that contained on the roll 34 of Fig. 1. In all other respects, the machines represent-ed in Figs. 1 and 2 are identical. Suitable film folding mecha-nisms are well known to those skilled in the art.

_g_ . 3 si~o~/s t~le var~ous staqes o~ ~/rappin~l of successive pctck~ge~ with the plastic film 31 as the packages pro-l ceed -throuJh the machille. Packac~e 16 is shown in Fi~s. 2 and 3 ilas ~ein~ par~ially cover~d ~y the ~olded film 31 as it passes into¦

i the invertinq hea~l 41. Package PS i.s shown exiting the side sealer S0 wi~h the selvage 32 of the film being separated from the side seale1 package PS and beill~ collectcd by vacuum hose 541.
The side seal 33 completes the tube envelope of relatively loose plastic filTn around packages P4 PS with a trim seal.
¦ The end sealin~ mechanism 60 produces a trim seal 34 ¦¦bet~een the packages P3 and P4 The end sealing mechanism also ! severs tlle plastic along the seal 34 so that packaye P3 is not only totally enclosed by the sealed film 35 but is also separated from thepackage P4 at the seal 34. The package Pl is shown as it exits from a heat shrink oven 70 where the loose fi~ting film envelope 35 around packaqe P3.can ~e shrunk to form a tight fittincJ ~ilm cover 36. .
~ he component parts and the assembl~ in combination of the continuous high-speed wrapping ntachille 10 of Fig. 1 will ~1 be discussed in detail.

r~

. ~ 3 INI`E~D CONV~Y~R

~ s stated carlicr, products are fed into the machine 10 by all ; n~cecl ConVeyor 20 of FiCJ. 1 W]liCh iS shown in more detail in the Eront side view of r~ig. 4. The infeed conveyor 20 com-prises a pair oE -transversely spaced, longitudinally~oEfset chain belts 25, 25', each in a vertical plane, which extend longitudi-nally along the conveyor. The chain belts 25, 25' are supported by driving pulleys 29, 29' and longitudinally separated idler pulleys 2~, 29~, respectively. The longitudinally ex-tend;ng upper portion of thebelts is supported by a longitudinal plate 202 in proximity to and under the longitudinally-extending slot 241 in the support surface 24. Plates 26 are positioned between the chain belts 25, 25' and are pivotally connected to the belts at ttto longitudinally separated points, one pivot connecti~on to each belt. The plates have detachably-connected vertical lugs 23 which project through the slot 241. A switch 231 is mounted on the conveyor in a position such that the lugs 23 may actuate the switch. The produc-t stacking feed 22 of conventional design may be u~ed with the conveyor 10 although other product feeds, well known in the art, are frequently used.
The products P which are to be wrapped in machine 10 are stacked above the infeed conveyor 20, as shown in Fig. 4.
The stac~incJ device 22 holds the products P so that they are transversely centered with respect to their subsequent line o travel through the machine and with respect -to the slot 241 of con~eyor 20.

. . .

... ;'~1. '`` -2k~413 l~ A power so~lrcc (not shown in F:icJ. ~ and to be disc~lssed ¦1 ]atcr] po~..els l:he drivc~ pul.ley 29' wllicll moves t:he chain belt 25' ¦ in ~he clire~t;.on 21. 'l`he pla~e 26 caUses the belt 2S to ~ove Ij at the speed o ~clt 25'. The lu~s 23 attached to the plates 26 ¦¦ are noved alollg the slot 2~1 in table 2~ in di.rectioll 21 and push ~l out the lowcrmost package P in the stacker 22. The lugs 23 o~plates 26 pUC;h on the trailin~J end of the packa~e P advancinc~
, the ~ac~age into the inverting head ~0 portion of the machine at i a predetermined spacing and a predetermined rate. As the lugs push the product along the top plate 2~ of the conveyor, the front and rear side guides 242 and 243, respectively, keep the packa~e centered on the lu~ 23.
Important features of the infeed conveyor 20 of this invention are that the lllgs 23 disen~a~e smoothly from~the pack-age as the package leaves the infeed conveyor lug 23 near the inverting head and that the lugs can get very close to the invert-ing head. In order to accomplish this, the lugs 23 maintain a ¦ vertical position near head 40 as tlley are brou9ht down from the , surface 2~ at the end 201 of the infeed conveyor 20. If only a single sproc~et and chain were usecl, the lu~s would s~ling forward and ~o~n. Therefore, in this invention two para-llel chains-are us ~c to provide a conveyor system where the lugs 23 always maintain a vertical postion.
¦ The plates 26 are positioned between the chains 25,.25' .
¦ with pivot point 27 of the plate 26 pivotally connected by a ¦ pin on chain 25 and the other pivot point 28 bein~ pivotal].y connectecl ~y a pin on cha.in 25' as shown in Fig. 5. The d.is-~allCe between the pivot points 27, 28 is equal to the ;ongituclincl:

Z~3 i! sepcll-c~tioll oE the c~nters of the sprocketed pulleys 29 and 29'(als( ¦29,~ a!lcl 29'~) aroul~ hi~l~ the c~lains 25, 25' travel. rulleys 29, 29' (and ~ulleys ?9~ allCI 29'A) havc their cellters in the same ~ ri-,.ontal plalle. ~hell thesc conditions are met, pla~es 26 will assu~le a horizontal pos;tion at all times as they travel aloncJ
llthc infeed conveyor t~ith the chains 25, 25' thereby maintaining ¦Ithe lugs vertical.
¦ The spacing bet~reen the lugs 23 inust, of course, be ¦greater than the longitudillal dimension of the package P, thus i!for large pac~ages there will be plates 26 to which no lug is ¦attached. Since the lug spacinq can only be placed at intervals lldetermined by the spacing oE the plates 26, it is necessary to vary the speed of the conveyor chains 25, 25' in order to feed the~ -¦packacJes into tlle inverting head with the desired spacing between ~ipackages. The spacing between the packages is controll~d by using j a speed variator 101 between the main drive system of 102 of the ~ machine 10 and the infeed conveyor 20. In the preferred en~odi-1~ ment of the invention, the speed variator 101 is a commercially i~ available variable speed transmission for varying the speed o~ the, ¦l ineed conveyor drive shaft 108 which is in turn connected to a ¦¦ drive (not sho~m) ~hich drives the sprocket pulley 29' of the infeed conveyor. Thus, if the speed of the infeed conveyor lugs 23 is increased, the spacillg between the packa~es as they exit the l inverting head 41 is decreased.
plate 202 securect to the top 2~ i5 spaced from and under the lonc~itudinal slot 2~1 to allow the plates 26 to rest on i tl~c p] a Le Z O Z and provid e s tab i l i ty c~ f 1 U3 9 2 3 ~h i l e tl~ e packa ~os -13- `
li I

? ~2~q4:~

¦~alC bO;ng PU~I1L~ 0D~J the top/collveyor 20 ~ torquc limiter ¦ clutch 10~ is provided between the OUtp~lt of thc speed varia-tor lOI and the in~e~cl conveyor drive sha~t 108. The torque limiter ~clutcll 109 Ca~lSeS tlle drive to slip in the evell~ tha~ the l.ugs 23 ~lexperience a force cJreat~r than -that normally to be expected in ¦Ipushin~ the packacJes along the table 2~ as when a jam-up occ-~rs ¦at head 40.
l Also shown on the infeed conveyor 20 in Fig. 4 i5 a ; ¦limit switcll 231 ~lhich can be moved longitudinally along the conveyor 0 and secured in a desired position by fastenlng to . stationary plate 232. The switch 231 is activated by the luys 23 as .hey return dowll the conveyor 20 to trigger the hole p~mch mechanism 37 shown in Fig. 1 or to sequence any other machine operation with the lug 23 movement.
Since -the inverting head is at an angle of ~ with respect to the direction 21 of product flow, the end 201 of conveyor table 2~ is caused to be at a 45 an~le as shown in Fig. 5. The angled end allows the slot 241 and table 24 to term-ina-te very near the inverting head 41. . .
Lug 23 is preferably secured to the.leading~edge of plate 26 which is nearest the inverter 40. This feature allows the lu~ 23 to approach very closely to inverting head 41 since it may ex-tend to the end of the slot 241 in top plate 24 of conveyor 20 and there~ore lug 23 acts as a positive force in inserting nearly the entire product into the film 31 at invertin~ head ~1.
'I'his ~eature results in the products bein~ evenly spaced in the film tube 3:l w}len exitillg the inverting head with a resultant iMprovemen-t in thc ~uality of the sealed packages at-the output of the machine 10.

4~L3 ,~,. . ~ .
I .
FII~I INV~R'l~ R

Thc fil~l inverter ~lO of this invention compr ses an inverting he~d 4L, a tri~nglllarl~ sllaE~ed table 42, and a fixcd bed 19 suppoltincJ a movable post 43 to which tlle head 41 is attached. The filminvertlng head ~0 inverts the film in the same manner as described in ~. S. Patent No. 3,583,8~8, for the automatic L-sealer. I~owever, because the machine of this inventio does not use an L-sealer, the film inver-ter 40 has been substan-tially modified.
~ s previously stated, the produc-t P is centered ~Jith respect to the inEeed conveyor slot 241 by means of guides 242 and 2~3. It is Xnown from the teaching of the patent referred to above, that the fold in the web of film 31 which occurs at the end 401 of the inverting head 41 should be close to thè edge of a product as the product enters the inverting head regardless of the product width. 'rherefore, the end 401 must be moved laterally wit respect to the slot 2~1 dependen-t upon the width of the package to satisfy this objective. It is also desired that the lugs 23 push the produc-t fully into the inverting head 40 independent of the width of tlle package.
In order to satisfy these objectives simultaneously, the inverting head 41 must be aligned with and moved in direction 45 at an angle of substantiall~ ~S with respect to the cdirection 21 of the packac~e flow. Il~he inverting head bed 44 whic}l supports head 41 has a slot ~8 at this 45 angle. ~ost 43 slides into this slot 48 moving invei^ting head 41 in direction 45. The lower arm 46 of -the head 41 moves alollg the edge ~7 of the table~42 whicl is also at the ~5 anqle.

':' . .. ' ,. .

1~ 3 The fold in film web 31 should be provided at inverting head end 401 substantially at right angles to the direction 21 of package flow for optimum operation of the inverting head.
Roll of film 34 is located in proper axial position by adjustable stops, not shown, so the fold of the film is in position for proper tracking over the inverting head 41. Since inverting head 41 is moved at a 45 angle to adjust for product width, film roll 34 will have to be shifted axially to malntain the alignment for adjusted positions of the inverting head 41. Where a center folder is usèd as in Fig. 2, the mechanism 30' also is moved along support rails on a base 300 to maintain the same relation-ship of the film with respect to the inverting head.
As the package emerges from the inverting head 41, there is film over it and between it and the tabie 42 so that the package will be carried across table 42 by the film onto the side seal conveyor 51 of the side sealer 50.

~ ~ .
FIL~ DISPENSER
. .
The wrapping machine 10 of this invention uses folded film 31 from a roll 34 as in Fig. 1 or from a roll 32 of flat film which is folded in the film dispenser 30' as in Fig. 2 to form a folded film 31. The film dispenser 30 comprises a roll 34 of film supported on two rollers 308, 309, a motor 39, a dancer roll 38, a hole punch 37, and another dancer roll 307.
A powered film unwind system is used in which a slight tension on the film web 31 raises dancer roll 38 to activate a - switch 301 which starts a motor 39 which drives roller 308 which turns the roll of film 34 (or flat film 32) in a direction to provide film to the machine. The motor 39 must at all times provide film in excess ii/

,.
: , i of the Illa~ill)UIll si)eecl of the ~r.ocl~lcts on the .infe~d conveyor 20 ;.n orcler to insu~e rllilli.n~lm terlsi.c)ll o~ ~he f;.lm as ;.t passes over thc I iJl`JCXti.llg hcad '~ is ap~al^ent, however, tha~ the drive mo~or ¦ may be dispe]lsc(l with i.f the roller 308 is clutclled into the main ¦l drive of the macl-lille, and the danccr roll 38 is used to control ¦¦ the clutch.
¦ The holc punch 37 ShOWII in Figs. 1, 2, and ~ comprises a cylinder 305 whicll has a thi.ck sponge rubber pad 306 to stop the I film 31 while a hole is being per~orated. The other cylinder 303 has a thinner rubber.pad 30~ mounted to a ball punch and a round die ~hich punches the hole in the film. Another dancer roll 307 is placed between the hole punch 37 and the inverting head 41 because the flow oE film at the inverting head 41 is continuous hereas the film flo~ is momentarily stopped at the hole punch 37.
The change from momentary stops in film flow to con~in~ous film ~low is absorbed ~y vertical motion of the dancer roll 307. As stated earlier, the hole punch cylinder 303 and the film stop cylinder 305 can be triggered by the adjustable position limit ~ switch 231 on the infeed conveyor 20 in which case a hole i.s located where wanted on each package. ~lternatively, the hole punch 37 may be triggered from a cam on one of the driving shafts of the machine so that a hole will be placed peri.odically along the film. The mode of operation that is used ~ill depend upon the type and size o~ package to be run and how much air should be vented out of it.
. .

~, L2~L3 SID~ SE~ LC1l~NISM

The side seal mecha1~ism 50 is shown in rela~ion to ~ilc ~ot:}ler portions of the packac~inc3 rnachir1e lO in I~ig. l and in detail in r~igS~ G and 7.
'rhe side seal mechanism 50 comprises a conveyor bclt 51 and a sidc sealer 52. The hei(3ht of side sealer 52 is adjustable with respect to belt 51 and both are attached to a frame which is movable laterally on rails 53 with respect to the line of ~ravel o~ the product down the machine. The side sealer 52 comprises !-two pairs of belts 56, 56', with idler pulleys 55, 55', and drive ¦pulleys 54, 54', whose drive is coupled to that of the conveyor belt 5l, a pair of jaws 58, 58', a heating element 521 along the edge of one of the jaws, sets of belt-pressure rollers 57, 57' on each jaw, an air cylinder 522 for moving one jaw into contact ~ith the other, and a pair of angled rollers 531 at the film input to said ja~s.
i As the packaye P6 of Fi~s. 2 and 3 leaves the inver~ing ¦head 4l, it is transferred to the conveyor belt 51 of the side seal mechanism 50. Since the packac3e always runs down the center line of the machine, it is necessary to adjust the side sealer 52 -toward or a~ay from the center of the machine in order to accom-moda-te narrower or wider packages. In order to accomplish this, the side sealer 50 is mounted on two parallel rails 53 fixed to the frame (not shown~ of the machine lO which rails run trans-versely to the direction of packac~e flow. Sealer 50 is moved away ~from or to~lard the center of the machine by convcs1tional means as by turnin~3 a crank attached to a scre~l (both not sho~n). The side sealer 52 produces a seal 33 at the free edcJes 310 of the film at the desired distance ~rom the edge of the packa3e.
. ' ' .
I

i~ 3 . I I

~ S sllo~n i.~ ia. I and in l;'.i~. 9, po~r is tr~nsmittcd t(~
the side seal~ Col~V(~yo~- 51 a~cl tl~e ~idc s~al~l- 5~ from th~ m.lin clrivc In~challi~;in 10~ to sha~t 103 t O shaL s 100 which has a key ~a~.
SII~t 100 is rotat:ahly mouIlte(l ~.o the Ina(Ilille 1rame. A sproc~
is rota~a~y secured by a bearillcJ (llOt shown) to a conveyor Ibelt 51 SUppoLt ~ram~ (not shown). Sprocket 104 haviI~ a captured ! ~ey slides alon~ the key way in shaft 100 as the conveyor 51 and ~side sealer 5~ ~re ntoved transversely. There~ore, as the shaft lOq jrotates the sprocket 10~ wi].l rotate no matter what its posi.tion a~;ially on the shaft. Thus -the sproc~et lO4 maintains a constant s~atial relationshi~ with respect to roll lOS which it drives by chain 104'. I~oll lO5 drives the conveyor belt 51 and the si.de sealer 52. Since the side sealer 52 is capable of being moved vertically with re~pect to conveyor belt 51 a spring tensioned idler pulley 5~1 is provided as a slack take~llp for theS~side seal drive chain 542 between the shaft of roller 105 and side seal belt drive gears 540.
Referrin~ to Fig. 6 a pair of laterally spaced V belts~

! 56 run between each drive pulley 5~ and a corresponding idler pulley 55. The upper and lower dri~re ~ulleys 5~ 54' ~and idler pulleys 55, 55l) respecti.vely rnay be vertically separated by a fixed distarlce su~ficient to cause the belts 56 56' not to be in contact when the machine is on "stand-by" (no product running).
The loose ends 310 of -the film 31 which encases the package PZ is inserted between the top pair of belts 56 and the bottom pair f bel.s 56'. Wherl a side seal is to be made, the belt 56 is movecl into pres.sure contact with belt 56' by idler rollers 57 attached to the up~er jclw 53 (film ends 310 interven.ing). Belts 56' are supported to resi.st the press-lre contact by idler rollers 57' jaw 58'. The upper jaw 58 has a hot seal wire 521 which runs along its lower edgss in a longitudinal direction. When the . , _ g_ "

Imachine is on st.<lnd-l)y, t)~e ~Ipper ja~ 58 is in its uppermost ¦~pos;tion ~1hcre ~he hot sc~l t~ire 52l is rellloved from the rec~ion bett~eel1 tlle elLs SG~ and 56~ wevcr, when ~he macl1iii~e lO is operatinc3 and a side seal 33 is being nlade, air pressure in the cy.1inder 522 acts to drivc the top jaw S8 down so that the upper rollers 57 pUS]1 the upper bel~-s 56 into pressure contac~ with the lo~er belts 56' and at the same time, the hot seal wire 521 moves between the belts 56 where it is placed in contact with the film 31 to produce the side seal 33 on the film surrounding pac~age P4.
Two guide rods 52~ keep the upper jaw 58 in alignment. A spring 525 on each guide rod 524 provides an upward force on the llpper jaw 58 when the air cylinder 522 is not enerqized to assure that the jaw 58 is in its uppermost position.
For simplicity, the precedin~ description of the sealin operation has for the most part avoided referring to t ~ fact that the upper belt 56 and its associated pulleys 54, 55, and 57 exis~
on both sides of the upper jaw 58. Where the description requires more specific identification of the ele~ents, -the elements on the side of the jaw farthest from the product being sealed-~carry the suffix A and those nearest carry the suffix B. The sanhe comment applies to the elements of the lower jaw 58'. It will also be seen that the jaws could be reversed so that the ].ower jaw could contain the heating element and could be removable from the seal re~ion.
The seal wire 521 run.5 along most of the len~th of the jaw 58 from the infeed end 526 to the discharge end 527. ~s the ilm has been sealed in -the sealer 52 and is emerging at the end 527, a vacuum llose 54l attached to a vacuuTn source 542~pulls the selvage 32 a~ay from the seal 33 before the selvage 32 has an opportunity to become reattached to the seal 33. Other means of removing selv~ge are known in the art ancl can be used.

-20- x, .1 . , 1.

2~4~l3 .

Since the package is being covered witll centerfolded IFilln, it is desiral~le to make the seal a~ the center of the heicJilt ¦!of the pao~a-Je. 'i`his is accolnplished by raising or lowerinc3 t:he~ ~
¦~sealer 52 by tu~ lC3 a cran~ 528 which with conventiona~ scre~ I
¦'mea]ls causes tlle sealcr 52 to ride up or down on a pair of parallel rails (not shown) ~hich ~re moulltecl to the con~reyor belt framc of ¦~the side sealer mechanism S0.
¦; ~nother ~eature of the sido sealer 52 is a set of Sprinc ¦,loacled 530 rubber guide rolls 531 located at the entrance 526 to the sealcr 52. The Eilm edc3es 310 to be sealed are engac3~d-hy ¦the rolls 531 prior to passing betweell the V belts 56, 56'. The Irolls 531 are mountecl on an arm 532 which is adjus-tabl~ connected ¦to the sealer 52 by a fastener 533. The rolls531 can then have I!their axes of rota-tion set transverse to the direction 21 of the ¦!flow of film in ~Jhich case a relatively loose wrap arou~d the ¦package is obtained; or if desired, the axis may be ang'~ed slightly off transverse to produce a pull on the film toward the sealer 50 ¦as the belts 56, 56' pull the film in the longitudinal direction i21, in which case the film will be pulled more tightly around the package. ~-The lower jaw 58' is sligh-tly recessed as by tapering at its input end 526' in order to facilitate entry of the film into the region bet~een the jaws since the -taper provides a ~ap jlbetween the upper jaw 58 and the lower jaw 58' into which the film I!is carried by belts 56. While in this tapered region, the film is ~in proximity with the hot seal wire 521 thereby permitting the fil~
to he prehea~ed and softened prior to its entry into the region where tlle wire 521 and the lower jaw 58' are in contact ~ithout the preheatincJ regioll, the ullsoftened Eilm wou]d be clamped b~tweell the ~ire 521 and th~ lower jaw 58' resultinc3 in a drag in the film¦

.

L2~ 3 . I I
Iwith t:he po~sil)i.li.t:y o~ tcaring t~le filln. Tl~at portion of the ¦~ide scal j~/s in ~llicl~ the wire ~; in intirnate con~act Wit'l the llo~er jat-J provi.~es ~he pressure ~e`tWeell the wi.ce and t:~ lower ¦Ija~ for severill~3 the fi]m aro~ ct tlle packacJe from the selva~ and , also provides a dwell -ti~e with the film .in i.nti.mate contact with ¦
¦ the }-eatilly wire which iS clesira~le ~or proper ~ormation of the ¦triTn seal weld bead.
:tt is seen that the above-described side sealer 52 in eonjunction with the vacuum source 542 produces a seal 33 at one edc,e of the package, and at the same time, severs and removes the l selvage trim 32. The products P4, P5 at this sta~e are spaced from eaeh other in a plastic film tube and are ready for the next step ¦
~o~ end sealing and separation from eaeh other.

END SEAL ~lECHANISM ~..

The end seal ~.echanism 60, shown in Fig. 1 and in more detail in Figs. 8 and 9 comprises a carriage 63 having bushings 63 which support it on horizontal shafts 633. On one side, carriage ¦
63 earries a vertical shaft 684' whereas on the other ~ide, car- ¦
riage 63 earries vertical support 685. The upper 632 and lo~er 631 jaws extend between bushinc3s 684 on shaft 684' and rest ¦
against supports 685. Each end of the upper jaw 632 is pivotally !
connec~ed.to spring loaded eonneetinc3 rod 652 which is pivotally eonneeted to an end of a roeker arm 650. Eaeh end of the lower ja~l 631 is pivotally eonneeted to eonneeting rod 651 whieh is pivotally eonneeted to the other end of roeker arm 650. The rocker arms 650 are rotatably connected to frame 683 and are rotated by erank 65~. Crank 654 is connected to crank 655 drivell~by a single revolution elutch 657 po~ered by motor 10~. -.
I -22- ~`' !l ~
CarJ-iacJe 63 is al.so conl~ctecl by pllSh rod 639, cranks 6~8, 635 allcl rod G37 to cLank 63~ driven by si.ncJ].e revolution cl~ltch 659 l~o~erecl ]>y mot:ol 106 to produce ]~ack alld f orth movemcr of ~h; carl-ia-Je.
~ rhc elld seal mecllanism 60 has ~wo cont.inuouC; conveyor belts 61 that r~n from an i.nfeed roll. 62 located in proximity to the belt Sl at the discharge roller 105 of the side seali}lcJ mecha nism 50. The belts 61 extcnd throu~Jll the end seallncJ carriacJe 63 to the end or discharcJe roll 6~. Each end seal conveyor belt 61 passes over several suupor-t rolls 65 and also drops down over a roll 66, under a bottom roll 67, and then over a roll 68 to forrn a U bet~een the infeed roll 62 and the discharc~e roll 64.
The top of the "U is at the same level as the belt 61 as it passes over the end rollers 62,64. The xolls 66-68 are supported by the carriage 63. The depth of the "U' 6~ is suffi-cient to allow the lower jaw 631 of the end sealer ca~-riage 63 to move down below the table surface formed by the belt 61. Belt 61 after it passes over the discharge roll 61, drops do~n to a roll 64]., passes under an idler roll 621, and then back to the in~eed roll 62 thereby completing the belt loop. Since there is not mucl belt ~7rap on ~he discharqe roll 64, both the discharge rol]. 64 an~
its associated return roll 6~1 are driven by chains 642, 642', respectively, throu~h approp~iate sprockets attached to the rolls Chain 642' is driven by shaft 643 which is driven by chain 644 which is connec-ted to speed reducer 102. Under normal conditions the speed of the end seal conveyor belts 61 is the same as the speed of the side seal conveyor belt 51 and the side seal bel.ts 5G .
In the operati.on of the end sealer, the end sealin~ carr ri.acJe 63, supported by bushings 63' on horizonta]. sha~t 633, move~
loncJitudillally in the cdirection 21 at appro~imately the same spee~ .
I

!l ~

Z~41~
as the package ln o~der to obtain time to rnake the end seal 34, shown in Fig. 3, without having to stop the movement of the package through the machine 10. As the carriage 63 moves up-stream in the direction of arrow 21 or downstream topposite to direction 21) the overall length oi the belt 61 does not change, but the location of the "U" 69 formed by the three rolls 66, 67, and 68 on the carriage 63 changes. Thus, ehe carriage 63 can be moved back and forth withouL changing the length of the belt 61 thereby eliminating the need for spring-loaded take~up rolls, etc.
The back and forth motion of the carriage 63 is obtained from a crank 634 located at the base of the machine which is connected by a connecting rod 637 to a crank 635 on an idler shaft 636. The idler shaft 636 acts as a form of bell crank with two cranks 638, one at each side of the machine.
By using two cranks 638, the end seal carriage 63 stays perfectly aligned during its entire travel back and forth during the sealing operation. The cranks 638 are connected to the end seal carriage 63 by pivoted push rods 639. One complete revolu-tion of the crank 634 causes the carriage 63 to move back and forth along the direction 21 to complete one cycle.
The end seal jaws 631, 632 are caused to come together and to open in synchronism with the longitudinal back and forth motion of the carriage. The jaws are brought together during the forward motion of the carriage 63 and at closure the jaws move at about the same velocity as the film surrounded packages. After completion of the sealing which occurs during the closing of the jaws, the jaws open sufficiently to clear the next succeeding package and travel back toward the inpuL roller 62 where they remain open and stationary until signaled to move in the forward ij/

1~2E~4~L3 direction and to close for the next sealing operation.
- The top end seal jaw 632 has an electrically heated wire 600 which runs along its bottom edge 601. The bottom edge comprises a layer of electrically and thermally insulating material which is capable of withstanding the temperature of the hot wire. The lower end seal jaw 631 has on its upper edge 602 a tetrafluorethylene fiberglass cloth backed with a silicone rubber pad and a sponge rubber pad. Springs 603 load a film clamp 604 on the upper jaw. ThP edges of clamp 604 (an inverted elongated U-shaped clamp) extend below and on both sides of the hot wire until the jaws are fully closed. The clamp 604 also helps to remove some tension from the film while the seal is being made. In order to make a seal, the top jaw 632 moves downward and the bottom jaw 631 moves upward until the two jaws meet at the center line of the packages. The motion of the jaws 631, 632 is accomplished by connectlng them to a rocker arm 650 by connecting rods 651 and 652, respectively. Each end of the jaws 631, 632 are so connected. The rocker arm 650 is connected by a shaft to a crank 654 located near the center of the shaft 653. The crank is in turn driven by a crank 655 to which it is connected by a rod 656. The shaft 653 connected to the two rocker arms 650 ensures that at all times the jaws move parallel to one another and that the sealing pressure is the same at both ends of the jaws. The crank 655 is driven at a speed about twice that of the crank 634 which provides the forward and backward motion of the sealing carriage 63.
The crank 634 is driven by chain 658 through a single revolution clutch 659. A single revolution clutch is one where after being energized the clutch will execute a single revolu-tion at which point it is automatically deenergized. Such clutches are available commercially. Chain 658 is driven by the iil ' ~ r~ ~
j, ll~B4~13 plain driv~ motor mechanism 102. Chain 65~ in t.urn providcs the !power to chain 6~0 by pulley 663 Oll shaft 661. Chain 660 provides !power to the crank 655 throuyll the clutcll 657 b~ a sprocket 66~
¦approximately half the diameter of the sprocket 663 on shaft 661.
¦ The single revolution clutch 659 is ener~ized to make a mechanical connection between the crank 63~1 and its corresponding ¦drive pulley 663 in response to an elec~rical signal ~rom either photocell 665 (or 666). An ener~izing electrical signal is pro duced by thc photocell 665 (666) when the liyht beam 667 (668) ~from light source 669 (670) ceases to be interrupted as at t~e end of the package. The photocell-light source combination 665, 669 is preferred for flat packages such as phonograph records;
hereas the photocell-light source combination 666, 670 is pre-¦ferred for packages of substantial height. Either one but not hotil of the pho~ocell-light combinations is used for a particular ~ackage run. As stated previously, the signal from the photocell 665 ~666) energizes the clutch 659. This clutch remains energized un~il automatically turned off by one complete revolution of the !cl utch .
¦ Switch 672 is controlled by cam 674 to -turn on single ¦revolution clutch 657 and to reset the photocell 665 (666) in readiness for the production of another energizing signal fro~
l the next package. When energized, clutch 657 rotates pulley 655 I nd cam 673 through a single revolution. Cam 673 closes switch 671 during the single revolution there~y applying a higher heating voltage to heating ~ire 600 using conventional circuitry.
Crank 655 will complete the closing and openin~ of the jaws 631 and 632 in the time that it requires for the seal I . ' ' "'' . .

. ~ 3 ¦assembly G3 to move from its rest position tv its farthest forwarcl position. It shoul(l be noted that the jaws ~re closed at a time when the crank 655 procluces ~he cJrea~est extellsion of the arm 656.
This provides a dwell time since the crank has the least effcct on i the motion of the arm 656 at: this ~ime. 'rhe c].osing o~ the jaws 631, 632 also occurs at a time when the harmonic motion of the carriaye 63 is at a point in its travel where the velocity of the carriage 63 is most constant, when the crank 634 i~ in a point in its rotation where the connecting rod 637 is approximately perpen-dicular to the crank arm 634. Constant speed could be obtained, if desired, by means of a cam.
The velocity of the jaws coming together is quite great as the toggle crank 654 starts its motion, but as the jaws meet, th~ top jaw 632 is on the bottom portion of the arc of the tocJgle ¦650 and the bottom jaw is at the top portion of the arc of the toggle 650, resulting in a decreased veloclty as the jaws approach one another so that the jaws close relatively gently and a continuation of the arc results in increased prcssure on the jaws by compression of sprincJ 682 located in connec-tinq r~ 652 and pro-duces a dwell time for the seal to be made.
Tlle jaws 631, 632 are opened and closed by connecting rods 651, 652, respectively. The connecting rod 652 betw~en the roc~er àrm 650 and the top jaw 632 comprises an inner sha~t 680 and an outer shaft 681 in which the inner shaft slides. These t~Jo shafts 680, 681 are connect~d by a lony spring 6~2 in such a way that afterthe jaws 631, 632 come together,further motion of the rocker arm 650 further compress~s the spriny 682.
~he compression can be adjusted to give whatever seal pressure 11 2 84 ~3 is req~lirecl. It should be notecl that the lonq travel of th~ upper jaw 632 obtainable with the long comL)ression spring prevcl~ts bind-ing of the end sealer in the evel~t tha'- ~ packac~e should l~ecomc entrapped in the end seal jaws. In the latter case, the sprincJ fi8 will mer~ly compress sufficiently to permit the mechanism to continue to operate without closing the jaws. This pressure is liyht enough so that a fairly s-tiff packaye will not b~ crushed by the jaws.
In order that the end seal be made near the center line of the package, the jaws 631, 632 are caused to be moved as~a unit in the same direction to cause the distance above the belt 61 at which they meet to be at tlle approximate center line of the pack-age being sealed. In order to accomplish this jaw movement, drive shaft 653, its bearings 691, and bearing !~upport plates692 are moved relative to the channeled housing 683 as shown in Fiq. 8.
As shaft 653 is moved up or down, the eonnectiny rods 651, 652 eause the jaws 632, 631, respectively, to also move up or do~Yn.
Locking elamps 698 seeure plates 6~2 to housing 683 at the desired height. The bearings 691 attached to plates 692 are moved in unisc n by individual screwdrives 693 which are in turn ro-tated by a common chain 694 attached to a sprocketed height control wheel 695.
Thus, rotation of the wheel 695 causes the screws to raise the shaft 653 for a high pro~ile package or to lower t for a low profile pae~age. The seal jaws 631, 632 are guided on one side of the carriage 63 by bushinys 684 on vertical shaft 684'. On th~
other side of the earriage, the jaws are guided by two pieces of vertically e~tendiny rectangular steel bars 685. The -top and bottom jaws have pads 685' of low Eriction bearing s~lrfaces boltec I , .

''` ~

iL312i~ 3 ~to them at the points o~ contac~ with ~:he ertica] supports 685.
The vertical s~lppor~s 685 are used rathcr than bus~ cJs in orcler to accommodate the expansion of the jaw~ withollt the binding which would occur i~ bushin(~s were usecl on bot}~ ~nds o~ ~he jaw5 since the jaws become hot as seals are being made.
The end seal drive assembly sho~n in ~igs. 1 and 9 has previously been briefly described in conjunction with clescribing ~the end seal operation and comprises a variable speed ~otor 106 driving a gear box 102 with an output provided with an overload prot~ction clutch-pu].ley 107. The power from clutch 107 is-pro-vided through chain belt bS8 to the pulley 663. When the machine 10 is running, the input drive pulleys 6~3, G64 to both single revolution clutches 659, Ç57, respectively, turn con~inuously.
It will be apparent to those skilled in the art that smoother operation of the jaw closing and more constant velocity ¦of the carriage could be obtained if a cam mechanism were utilized ¦rather than cranks where the increased complexity is justified.

SEAL WIRE HEAT CONTROL

The side seal film heating wire 521 and the end seal heating wire 600 have low heat input for idling conditions and a high heat input for the condition where thc machine is rullning pxoduct and seals are being made.
In the case of the side sealer 52, the idle heat settin occurs when the jaws 58, 58' are open and the machine is in its stand-by condition. High hea~ input ~o the wire 521 is estab-lished by a switch unit 522' when the pneumatic cylinder 522 ~is actuated to close thc jaws whell thc mc~chine is runninCJ. The ¦circuitry to accomplish the elcctrical switchincJ ~ill be clear to those skillcd in the art from the presellt disclosure.
In the case of the end seal mechanism 60, tlle end seal jaw lleatillg elemen~ 600 is under the low heat idling condition at all ~imes exeept w~leil the jaws are beincJ closed when making seal. The initiation of the high heat condition is by cam-controlled limit switch 671 when cam 673 is rotated by the single revolution clutch 657 of the end seal jaw Mecllanism as expl~ined earliPr .

CONCLUS I ON

It is apparent from the forecJoing description of the machine 10, where reference is made to control of pneumatie c~linders actuating certain devices such as the side sealer and the hole puncher, a photoelectric cell controlling the energizatior of a magnetic clutch, eontrol of the heat of heating elements 600 and 521, the motor controlled feed of the ~ilm ~nd the like can be asser~led from control mechanisms ~nown to those skilled in tile art. Such control mechanisms may be contained within the control box 80-shown in Fig. 1. Since the functions of these various valves, switches, clutches, etc., have been yiven in detail, it is believed that those skilled in the art will not need a detailed description of the electrical and pneumatic circuitry ~hereby these elements are interconnected to practice this invention.
~ lso, a phol:ocell 665 (666) has ~een used to trigger the initiation of the encl sealer ~0 in the prefcrred embodiment b~-cause it has been found that this form of control is the most conven~ent when packages arc- to be wrapped whicll change in lenc~tl . ' ' '.
~ -30-!!
:` :

~2~

from run to run. In the event of a single product machine, however, such as machines wrapping long-playing records, it should be understood that the end seal mechanism 60 may be directly linked to the main drive of the machine and synchronized with the inflow of the records to the machine without requiring photocell initiation of the end sealer.
Also, a belt infeed conveyor without flights could be hand fed with any length product provided that the spacing of products was accomplished manually. This would be particularly useful for long products such as shelving and door trim. In this type of machine, the infeed conveyor belt would always run at the same speed as the side sealer belt thereby eliminating the need for a speed variator between the main drive of the machine and the infeed conveyor. For non-high speed uses, the machine can be used with an intermittent feed by stopping thé conveyors and end seal motion during the end saal operation thereby eliminating the need for carriage 63 to be moveable. If suffi-cient time is available for the end sealing cycle, jaws 631, 632 could be operated by simpler means such as air cylinders.
It is evident that those skilled in the art, once given the benefit of the foregoing disclosure, may make numerous Dther uses and modifications of, and departures from the specific embodiments described herein without departing from the inventive concepts. As previously stated, the upper and lower sealing jaws may be reversed as to function with the heating element on the lower jaw instead of the upper as described. Hence the use of such terms as "upper" and "lower" in the claims is not to be con-strued as a limitation to the orientation shown in the drawings.
Consequently, the invention is to be construed as embracing each and every novel combination of features present in, or possessed by, the apparatus and techniques herein disclosed and limited solely by the scope and spirit of the appended claims.

iil .

Claims (6)

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

1. An automatic film wrapping machine for wrapping products in heat sealable thermoplastic film in which -the flow of products through the machine is substantially continuous and in a straight line comprising:
a film inverting head, an infeed conveyor for providing packages to the input of said inverting head, means for providing folded film to said inverting head, said inverting head inverting said film and enveloping said packages in said film while said film is substantially tension free, a side sealing means for continuously heat sealing the free edges of said folded film in proximity to said package, severing excess selvage from the package and drawing said film over said inverting head, means for removing the selvage of the film after said film has been sealed, an end sealing mechanism having sealing jaws, means for providing said side sealed packages to said end-sealing mechanism, means for closing the sealing jaws of said end sealing mechanism on that portion of the film between the packages to simultaneously seal the ends of said packages and sever the film between successive packages at the seal, said sealing jaws moving at approximately the same velocity and direction as said film where said jaws are closed, said sealing jaws moving in the opposite direction to said film after said seal is made and said jaws are opened, said end sealing mechanism having means to deliver said sealed packages to the output of said machine.

2. Apparatus according to claim 1 wherein:
said inverting head extends at substantially an angle of 45°
with respect to the londitudinal direction of travel of said product -through the machine and including:
means for movably supporting said inverting head on a fixed bed to allow movement of said support means and said inverting head in -the direction of the ex-tension of the inverting head to adjust for different product widths.

3. An automatic film wrapping machine for wrapping products in heat sealable thermoplastic film in which the flow of products through the machine is substantially continuous and in a straight line comprising:
an infeed conveyor for feeding said product into said machine at a continuous velocity and spacing, a folded film inverter, a film supply for providing folded plastic film to said inverter, a side sealer, .
said product being inserted in-to said inverter by said conveyor and surrounded by said film in said invertor while continu-ing to travel at said continuous flow, said inverter providing the edges of said film at one side of said draped product to said side sealer, said side sealer adapted to receive said film covered products from said inverter and sealing said edges while said product is running at a continuous velocity to form a tube of film containing said products with substantially uniform spacing and severing excess selvage from said tube of film, an end sealer, said side sealer providing said film covered products to said end sealer, (Claim 3 cont'd) said end sealer providing a seal transverse to said tube of uniformly spaced products while said products are travelling through said end sealer at a substantially continuous velocity, said end sealer severing the film tube between adjacent products lo provide individually sealed packages at the output of said end sealer, said end sealer comprising:
an end sealer conveyor belt having a horizontal table portion, said end sealer conveyor belt being adjacent to and adapted to receive said side-sealed film products from said side sealer conveyor belt, means for moving said end sealer conveyor belt in a londitudinal direction, an upper and lower sealing jaw, a rocker arm having a centrally-located pivot point, a rod pivotally connected at one of its ends to one end of said rocker arm and to said lower sealing jaw at its other end, a spring-loaded extensible rod pivotally connected at one of its ends to the other end of said rocker arm and to the upper sealing jaw at its other end, a first crank connected to said rocker arm, means including a first single-revolution clutch having its output shaft connected to drive said first crank, said first clutch having an input shaft connected to a first drive pulley, said upper and lower jaws being guided by a carriage, said carriage being supported on longitudinally extending horizontal rods, means for moving said carriage back and forth in said longi-tudinal direction, (Claim 3 cont'd) a second crank being connected to said moving means, means including a second single-revolution clutch having its output shaft connected to drive said second crank, a motor, said first and second clutches having input shafts connected to said motor to rotate in response to rotation of said motor, means for providing an electric signal in response to a package on said end seal conveyor belt, said second clutch being responsive to said electric signal to connect its output shaft to its input shaft to rotate said output shaft through one revolution, a switch connected to said second clutch output shaft to energize said first clutch upon initiation of rotation of said second shaft, said energized first clutch connecting its output shaft to its input shaft for one revolution of the output shaft, the input and output shafts of said first clutch rotating substantially at twice the rate of the input and output shafts of said second clutch;
said first clutch output shaft single-revolution causing said upper and lower jaws to close and then open by moving said first crank through a single oscillatory motion and return to their original positions, said second clutch output shaft coupled through said crank to said carriage during its first half revolution causing said carriage to move forward at substantially the velocity of said end seal conveyor belt when said jaws are closed, said carriage comprising rollers to provide a "U"-shaped depression in said end seal conveyor belt in which said lower end seal jaw may Move vertically, said depression moving longitudinally with said lower end seal jaw, said carriage moving to its most forward position from its rest position while said jaws are being closed and opened, said second clutch output shaft during the second half of its revolution causing said carriage to return to its rest position while said jaws are in their open and rest position, said upper jaw having a heating element along the lowermost edge to cause said film to seal when said jaws are closed, said upper and lower jaws being adjustable to close at the height of the elevation center line of the package.

4. The film wrapping machine of claim 3 wherein said end sealer spring-loaded extensible rod is capable of being addi-tionally compressed when said upper and lower jaws are closed, said additional compression being sufficient to allow said jaws to close on said package without jamming.

5. An automatic film wrapping machine for wrapping products in heat sealable thermoplastic film in which the flow of products through the machine is substantially continuous and in a straight line comprising:
an infeed conveyor for feeding said product into said machine at a continuous velocity and spacing, a film inverter comprising:
a fixed bed, an inverting head extending at substantially an angle of 45°
with respect to the longitudinal direction of travel of said product through the machine, means for movably supporting said inverting head on said fixed bed to allow movement of said support means and said inverting head in the direction of the extension of the inverting head to adjust for different product widths, a film supply for providing folded plastic film to said inverter, a side sealer, (Claim 5 cont'd) said product being inverted into said inverter by said infeed conveyor and surrounded by said film by said inverter while continuing to travel at a continuous flow, said inverter providing said surrounded products to said side sealer, with the free edges of said film at one side of said surrounded product, said side sealer being adapted to receive said film covered products from said inverter and to seal said free edges while said product is running at a continuous velocity to form a tube of film containing said products with sub-stantially uniform spacing and sever excess selvage from the package and drawing said film over said inverting head, means for removing the selvage of the film after said film has been sealed, an end sealer having sealing jaws, said side sealer providing said film covered products to said end sealer, said end sealer providing a seal transverse to said tube of uniformly spaced products while said products are travel-ling through said end sealer at a substantially continuous velocity, said end sealer severing the film tube between adjacent products to provide individually sealed packages as the output of said end sealer means for closing the sealing jaws of said end sealing mechanism on that portion of the film between the packages to simultaneously seal the ends of said packages and sever the film between successive packages at the seal, said sealing jaws moving at approximately the same velocity and direction as said film where said jaws are closed, said sealing jaws moving in the opposite direction to said film after said seal is made and said jaws are opened, said end sealing mechanism having means to deliver said sealed packages to the output of said machine.

6. An automatic film wrapping machine for wrapping products in heat sealable thermoplastic film in which the flow of products through the machine is substantially continuous and in a straight line comprising:
an infeed conveyor for producting product input to said machine comprising:
a table having a longitudinal slot extending to at least one end, and an end edge at 45° to said slot, a pair of chain belts, a plurality of pulleys arranged to support each chain belt in a vertical plane, each belt extending longitudinally along and under said table and vertically at the table end, each belt being transversely spaced from said slot on different sides of said slot, the upper portions of said belts being in proximity to and extending longitudinally under said table, a plurality of horizontal plates each pivotally connected to each chain belt, said pivot connections having a longitud-inal displacement on each plate which is the same as the longitudinal displacement of corresponding points on said chain belts, a plurality of lugs, each removably and transversely connected to a different plate and projecting vertically upward through said table slot, means for driving at least one pulley of a chain belt to cause said belts to rotate in said vertical planes about said pulleys, to cause said plates and lugs to move along said slot to the end of said slot.
said slot terminating at said end edge of said table, said lugs maintaining their vertical projection at the slot termination at the table end as said plates move vertically to cause said lugs to retract below said table, (Claim 6 cont'd) a folded film inverter, a film supply for providing folded thermoplastic film to said inverter, a side sealer, said product being inserted into said inverter by said conveyor, said inverter inverting said film and enveloping said products in said film while said film is substantially tension free and while said products continue to travel at said continuous flow, said inverter providing said surrounded products to said side sealer the free edges of said film at one side of said surrounded product, said side sealer adapted to receive said film surrounded products from said inverter and to heat seal said free edges in proximity of said product while said product is running at a substantially continuous velocity to form a tube of film containing said products with substantially uniform spacing, said side sealer severing excess salvage from said products and drawing said film of said inverter, an end sealer having sealing jaws, said side sealer providing said film surrounded products to said end sealer, said end sealer including:
means for closing the sealing jaws of said end sealing mechanism on that portion of the film between the packages to simultaneously seal the ends of said packages and sever the film between successive packages at the seal, said sealing jaws moving at approximately the same velocity and direction as said film where said jaws are closed, said sealing jaws moving in the opposite direction to said film after said seal is made and said jaws are opened, said end sealing mechanism having means to deliver said sealed packages to the output of said machine.