Note: Descriptions are shown in the official language in which they were submitted.
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~ E`it ContaLner AG, CH-7000 Chur, Bahnhofstrasse 8 (Switzerland)
~: Production procedure for the manu~acture o~ blanks ?. -- ~. ~
for producing folding cartons as well as e~uipment - . .
for the erecting and welding of same 'U~TRASONIC !
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The invention presented here concerns a process and a-manu~ac~
turing procedure -to erect carton blanks the printed surface o~ :
~`. ` which is coated with a protective varnis~ and join together the. :~.
exea~ed parts facing each other~
The manufacture of folding car~ons from die cut blanks ~oresees
the application of heat sensitive adhesive to those pa~ts ~hi.ch~
are to be j~ined together immediately prior to int~oducin~.the
blan~ into ~he erecting tool thus enabling one part to adhere
to the other. Particularly during continuous ma~u~acture and - :
allowing fQr stoppages and faulty blanks the erecting mecha~ism
inevitably accumulates a considerable amount o~ di~t whlch in ~ 5 . :
turn leads to high maintenance chargesO Should, however, the ad~
hesive be applied to the blank earlier on, then special heating
equ~pment would be necessary to re-activate the adhesive. Final-
ly in the case of synthetic products of weldable material throuyh- -
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out, alternatively ~naterial with a coating of weldable synthetic
material, special hot air jets would ~e re~uired to heat and
soften the appropriate par-ts of the blank which are to be welded
prior to guiding the blank in to the erectiny tool.
Quite apart from the fact ~hat the s~eps outlined abave are
costly, they are also hostile to the environm~nt and what is
more require a considerable amount of energy to heat up the
adhesive or parts of the blank.
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Furthermore the entire surface of the previously p~inted blanks -
is continuously given a coating of protective varnish to pr~tect ~
the blanks against mechanical damage and to improve the sllpping -
~properties during the erecting procedure. A dispersion varnlsh
; is used as protection varnish. -
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The object of thîs invention is to avoid these drawbacks and to
~establish a method including suitable equipment which provldes asimple and energy saving process for welding togPther the indi-
vidually prepared blanks in a way that is also fxiendly to the
environment.
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The solution to this pro~lem lies in the following. At lea~t 1
o t~e ~ sides ~f the blank facing each other to be joined to- ;
gether are coated completely or in part with~a varnish o~ high
solid content which is simultaneously serving as protection~var-
nish, As soon as the blank has reached the point of application
at the consumer's plant it is run through a special erecting unit~
The varnish applied to the blank is activated by the ultrasonic
waYes which heat up the sealing area, thereby making the v~rnish
at least stickily liquid and thereby~weldable~ ~
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~; This method of joining the blank parts by using ultrasonic waves `
is the object of this invention. The dispersion varnish covers
the entire surface of the blank, serving as pro~ection varnish
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for the printed axea and as dispersion varnish for those parts
of the blank which are welded together, all this in a single
operationO No further operations are required. A perfect and
clean weld is achieved. ~here is no surplus Adhesive ~ein~
squeezed out along the edges of the weld which could smudge on
to the carton. What is ~lore, -there is no need to allocate time
for preparato~y work when applying ultrasonic waves, as opposed
to ho~melt and similar adhesives which need time to warm up,
cleaning and other preparatory work.
As far as the actual varnish applied to the blanks is concerned~
the appropriate propor~ion of the ingredients would be appXox~
40~ acrilic resin and approx. 60% solvents which should preferab- ~
ly be watex with an add,ition of ammonia. This varnisll also has ~ ~,
the advantag~ of high viscosity whereby the volume o~ flow mea-
sured with a 4 m~m DIN cup would be approx, 60 - 70 seconds.
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The application of this varnish to the various ~lanks or parts ~ i
thereo~ is for all practical purposes best done by offset printO
The quantity of varnish to be applied should ~e around 7 ~ 8 `'~
grammes/wet weight per sqm.
To assure a s~ooth ~low of the varnish to the printing ma~hine ~-
it ls an adva~tage ~o keep it in a c~ntainer fitted with a cy- ~
lindrical mould lagitator~ and a pump preferably of th~ centri- ;
fug~l variety~
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Ater the bla~ks have received the treatment outlined above
they can be put through an autoplatten or similar machinery for
die cutting in the usual manner and subsequently supplied in '-
the ~lat to the consumer for further processing. To continue ~`
the process nf this invention it is advantageous to use an ap-
pliance which is co-ordinated with the erectin~ tool on to
which at leas~ one ultrasonic unit is mounted to syncllronise
with the tool plunger and pressi~g against the carton flap to
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be welded wher~by ~he pisLon oL the un it slides out ~xertiIIg
the required pressure ~o the carton flaps to be welded and
then immediately returns to its previous position.
If the blanks to be used are in part or throughout coated
with synthetic material then the parts to be welded are hea-
ted by ultrasound at the connecting areas so that they can
be welded intensively, particularly when the head of the ultra~
sonia unit is pressed fir]nly against the carton parts to be
welded, whereby the plunger of the erecting tool inside the car-
ton being formed acts as anvil. If on the other hand the ~lan~s
to be erected are made of uncoated board, then the varnish of
high solid value having been applied to the necessary parts in
the manner described heretofore is react1vated by the ultraso-
nic equipment and thereby made weldable.
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The ef~ect of ultrasonic equipment can be further enhanced ~y
providing projections on the ~arts of $he plunger o~ the çrec-
ting unit which then serve as anvil being immediately opposite
~he ultrasonic units. This would increase the specific area
pressure during the application of the ultrasonic unit. Th~se
pro~ections can have either pointed or blunted tips. They can
also be de~eloped as shaped ribs which penetrate the board of
the blanks which are to be welded, so that the dis~ance to th~
head of the ultrasonic equipment is reduced thereby improVing
the ef~ect of the ultrasound.
~urthermore, it is of advantage if the appliance as outlined in
this invention is equipped with a number of such movabl~ ultra
sonic units which should appropriately operate jointly and in
pairs being positioned opposite one another.
These ultrasonic appliances can also be moved pneumatically,
and it is possible to adapt both the forward and retracting
speed individually accordin~ to the circu~l~tances by fittin~
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rocker arms between the ultrasonic appliances and the
pneumatic power unit.
Therefore, in accordance with the present invention,
there is provided a method for forming cartons from sheet
material blanks having sealing portions. The method comprises:
coating the blanks at sealing portions thereof with a varnish
comprising thermoplastic solids in a liquid vehicle, the
solids being present in sufficient amount to form a thermo-
plastic seal, joining the sealing portions and positioning
between a sonotrode face and back up anvil sealing surface
carrying a plurality of space projections, compressing a
sealing area of overlapped sealing portions with the
projections biting into the portions to effectively deliver
ultrasonic energy near to a seal line reducing the distance
between the anvil s~aling surface and sonotrode to increase
the effect of ultrasonic energy used to form a seal and
heat sealing the portions using the sonotrode to seal the
portions.
In accordance with a second aspect of the invention
there is provided an apparatus for welding the overlapping
portions of folding or rigid cartons formed from flat blanks
coated on at least one side of each pair of overlapping portions
with a varnish containing thermoplastic solids. The apparatus
comprises: an anvil surface with a plurality of discontinuous
projections thereon, a sonotrode wi-th a flat face, and means
for clamping the overlapping portions between the sonotrode
and the anvil surface with sufficient force to compress the
overlapping portions in contact with the projections on the
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anvil surface, thereby reducing the distance between the
sonotrode and the anvil at the welding interface of the
two overlapping portions, increasing the pressure at the
weld/ and forming a mechanical interlock at each weld.
Further details of the procedure according to this
invention and its application are outlined in the following
drawing showing an applied project as an example and the
consequential claims as the outcome of this invention.
The illustrations are:
Fig. 1 Diagram of the equipment with blank fed in
Fig. 2 Illustration according to fig. 1 but
showing the erected blank
Fig. 3 Application of the sonotrodes
Fig. 4 A selector of fig. 3 on a larger scale
Fig. 5 Interval and
Fig. 6 Illustration according to fig. 1 showing
a second blank fed in and the erected
first blank
In fig. 1 the strictly diagramatic ill~stration of
the erecting unit 1 shows a shaping plate 2 which in this case
has a rectangular opening 3. Below the shaping plate 2 there
is a firmly fixed forming well 4 which can be fitted with an
anci]lary base 5, if required as wellas support guides which
have not been particulary illustrated. Above the shaping
plate 2 there is a plunger 6 moving downwards in the direction
of the arrow 7 through the opening 3 of the shaping plate
2 and through the forming well 4.
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On both sides of the forming well 4 are the heads
of the ultrasonic appliance, the sonotrodes 8 and 9,
producing ultrasound. These sonotrodes 8 and 9 move
horizontally in the direction of
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the arrows marke~ l0 .~ionc3 ~lle guidc rods marke~ Jhi~h in
turn are connected to ~he pneulllatic cylinder 12 AS shown in
fig. 1. I~ere it is possi~le, as can be seen in fig. 2, to fit
a swivel-mountecl rocker al-m (rocker disc) 14 between the yuide
rod 11 and the pneur,latic cyl inder 12 whi~h is mounted on a pivot
13 to which the ~uide rod 11 on the one hand and the piston rod
15 of the pneumatic cylLnder 12 on the other are connc-cted.
The operation of this appliance according to the inverltion is as
follows: ~irst of all a blank 16 is put into position between the
pulled up plunger 6 an(3 the shaping ~late 2 as seen in fig. 1
Those par~s of ~he blan~ which are to be welded together by
ultrasound have receiv.d an applica~ion of varnish of high solid
con~ent which has meanwhile hardened. After feeding in this blank
16, made of board in tl~is case, the plunger 6 moves down in the
direction of the arrow 7 taking the blank 16 with it, so that
the flaps 17 are bent upwards as they pass through the opening 3
in the shaping plate 2 therehy skimming the outer frame 18 of the
plunger 6 as per fig. 2. ~or the sake of clarity forming tunnel
4 and ancillary ~ase 5 are left out in fig. 2.
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Once the procedure of .recting the flaps 17 of ~lank 16 is termi~
nated, the pneumatic cyliliders 12 allocated to the sonotrodes 8
and 9 ~o into actlon and push the sonotrodes 8 and 9 in the di-
rection of the arrow 1~ against the flaps 17 of the erected blank
16i the plunger 6 serving as counter support. As the sonotrodes 8
and 9 are positioned ol~posite one another, the pressure exerted
by tha pneumatic cylin(lers 12 is cancelled.
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To increase specifically the area pressure of the flat ends 19
of ~he sonotrodes 8 and 9, the outer frame 18 of the plunger 6
to which projection pins 20 pointing at the ends of the sonotro-
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des 8 and 9 respeci,i~ely J~a~e beel1 fitl:ed, serves as anvil as
can he seen in fig. ~ e inside sur~aces 21 of the b]ank 16
and the parts of the f1aps 17 wl~ich ~re to be welded together
lie flat against these projection pins. lf these projections
have a ribbed surface or projecting points, then these ribs or
points penetrate into the parts of the blank~ pressed against
them, thereby reducing the distance between the pluncJer 6 and
the sonotrode facing it which brings a corresponding increase
of the effect of ultrasound. To achieve a direct ~ontact bet-
ween the end flaps 1g ~)f the sonotrodes 8 and 9 and the side
flaps 17 of the blank, it is possible to cut out sec~ors of
the forming well 4 thr~ gh which the sonotrodes 8 and 9 can
pass. Incidentally the forn1ing well has been omitted from the
diagrams fig. 2 to 5.
As soon as the end flaijs 19 of the sonotrodes 8 and ~ press
against the side Ela~s of the blan~ 17 and thereby against the
projections 20 on the sides of the plunger 6, the ultrasound
turned' out by the sonotrodes 8 and 9 heats up the synthetic ma-
terial of the blank, alt~rnatively the coating of synthetic ma-
terial which has been applied to the blank, thereby welding the
side flaps together. lf the blank 16 is made of board and has a
coating of ~arnish - a~ outlined earlier on - then this is like-
wise h a~ed up by ultrasound and the adjacent flaps are welded
together with this heated varnish of high viscosity.
As per ~ig. 5 the sono~rodes 8 and 9 press against the blank
flaps 17 for a silfficient length of time to weld the synthetic
material and/or to harden the varnish between the blank flaps
17 thereby completing the welded join-t. The ~olded carton 22 i~
thereby produced.
Once this procedure is ~ver, the sonotrodes 8 and 9 are rctrac-
ted in the opposite dilection of the arrows 10 return,in~ to
their starting point - as shown under fig. 1 and 2 - and the
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plunger 6 is pu~l~c~ ~Ip in t~le (~pposi~e direction of ~he arrow
7. The support ~3~ides ~It.tached to th~ forming well 4 which are
not specially illustra~ed, hold the finished carton 22 in po-
sition as sllown in li~. 5. ~hen the plunger 6 has reached its
original raise~ posi~ion, then a new blank 16 is fed on to the
shaping ~late 2, thereL:y enabling a re~etition of the proce-
dure outlined a~ove. ~ ilst moving down again, the plunger 6
erècts the second bl~nk 16 and thereby ejects the previously
completed foldin~ carton 22 downwards. :~.
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Referenc~ ~l'a~le ~;uide)
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1 Erecting unit
2 Shaping plate
3 Opening in 2
4 Eorming well
S Ancillary base
6 Plunger
- 7 Arrow
8 Sonotrode
9 Sonotrode
Arrow
uide rod
12 Pneumatic cylind~r
13 Pivot
14 Rocker arm ~rocker disc~
15 -Piston rod of 12 .
1 b Blank
17 Blank flaps of 16
18 Outer fram~ of 6
1~ End flaps of 8 and 9
Projections on 18
21 Inside surface of 17
22 Folding carton
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