Note: Descriptions are shown in the official language in which they were submitted.
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_
28413
. 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.
-15-
':' . .. ' ,. .
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
- 16 -
ii/
,.
: ,
4113
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 -18-
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_ "
13
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
-23-
!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
- 24 -
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
- 25 -
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
-26-
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
-27-
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.
- 31 -
iil .
