Note: Descriptions are shown in the official language in which they were submitted.
570S9
Background of the Inven ion
Textured foil of the type to which this i~ention
applies is used in packaging of commodities and appears
most often in the make-up of retail packages. An example
of this type of foil is found in packages designed for
marketing of cigarettes. The metallic part of the foil
forms an excellent vapor barrier and is desired for this
purpose as well as for wrapping and adding attractiveness
to the appearance o~ a pack of cigarettes. In the
operation of cigarette packaging machinery it is usual
to advance a foil-paper laminate into the equipment
at a rate sufficient to supply each pack of cigarettes
with the amount of foil necessary to make up a given
package. The foil component is combined cooperatively
- with other components to make up a complete cigarette
; 15 pack containing a standard number of cigarettes. The
pzckage is overwrapped and sealed to make it air tight
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then placed in a carton.
The prior art devices for processing the foil
to emboss it comprise texturing rolls which are of co-
operating complementary male and female die members
arranged to rotate into register for forming bosses in
the foil at the nip of the forming rolls. In one such
device, the pair of rolls consist of one roll made with
rigid male forming plugs. This is caused to run in
compressive contact along a nip line against a roll ¦~
surface with a resilient polyurethane covering. The foil
is pressed into the yieldable surface of the polyurethane
covered roll by the male forming bosses to form bosses
in the foil.
These above methods are widely used in cigarette
making and packaging machinery, but an inherent problem
associated with the feeding of the textured oil is
caused by the tendency of the textured foil made by
former methods to curl and cause it to be difficult to
~~ 35 guide through automatic machinery. Tendency to curl
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requires that more highly engineered ~uide and control
features be provided than for a foil which lies flat.
A flat foil will advance a greater distance through
packaging machinery wit]-out the need for excessive guiding
and controlling apparatus specially made for the express
purpose of keeping the foil flat while it is manipulated
in automatic handling. -
Summary of the Invention
It is an object of the present invention to pro-
vide a method for embossing a sheet of foil to producea textured sheet relatively free of an inherent tendency
to curl.
It is a further object of the present invention
to provide apparatus for implementing the above method
of this invention.
The present invention achieves the production of
relatively cur~free textured foil by embossing the foil
while localizing the effects of lateral dimensional
deformation in the foil to the immediate surface area
of each individual boss. By this is meant that in
drawing the foil to produce an individual boss, the
surrounding perimeter about the base of the boss is
held in place, stabilized dimensionally, and is maintained
so while the final drawing of the boss takes place.
A male die in contact with the foil presses against the
foil to drive and draw it into a complementary rigid I`
walled female die to ~orm the boss. A yieldable ~aterial
is made to interlie the opposite surface of the foil and
the surface of the female portion of the forming dic.
The yieldable material deforms uniformly along with the
- foil being drawn to provide a cushioned surface mating
area between the surface of the foil and the walls of the
female die.
The compressive characteristics of the yieldable
material are such as to distribute the compressive forces
~, uniformly over the stressed area of the foil under contact
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for drawing it into conformity with the general form of
the walls of the individual female die cavities. Thus
the foil is relatively unimpeded in its freedom to deform
yet is resiliently and forgivingly supported in the
- desired final configuration between the forming members.
In this manner only that area o foil which is included
within the perimeter of each boss is apt to be affected
in lateral dimension while being drawn to form a
particular boss. A minimum of curling is thus imparted
to the rest of the sheet of foil as embossing action
proceeds. Since the drawing action for each boss is
localized, an uneven lateral distention of the bulk
of the sheet of foil is held to a minimum.
Brief Description o the Drawin~s
Figure 1 is a side view in elevation showing
a pair of embossing rolls and web and foil feed bobbins.
Figure 2 is a side view in elevation showing
the embossing rolls of Figure 1 and a feed bobbin of
prelaminated foil.
Figure 3 is a view in elevation showing an
enlarged detail of the embossing rolls of Figures 1 and 2.
Pigure 4 is an enlargement of a single pair
of embossing dies with foil in place.
Description of the Preferred Embodiments
Referring now more particularly to the drawings
and specifically to Figures 1-4 thereof, the apparatus
of Figure 1 includes rotatable supply rolls or coils
10 and 12 commonly referred to as bobbins in cigarette
manufacturing nomenclature. Roll 12 carries a supply of
a metallic foil 1~, such as aluminum foil, in strip
form of a width suitable to a pre-selected use~ and roll
10 carries a supply of resilient or deformable buffer
material 20, such as paper or plastic sheet material.
The metallic foil may be o a range in thickness of
3~ from .0001" to .030" and of a surface quality preselected
to produce a desired effect after embossing. The
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thickness of the buffer material 20 may vary in thickness
of up to ten times the thickness of the foil as is found
to be best by experiment -for a particular foil thickness,
W~.ile the present invention will be described
5as being applied to embossing of metallic foil, and
particularly for cigarette packaging, it will be under-
stood that the material to be embossed may be used for 'I
any purpose and may be made of any-ferrous or nonferrous
metal or combinations thereof. Plastic or paper materials Z
10to which a metallic coating has been applied may also
be used. It is also contemplated that the present
invention may be practiced in connection with the use of
heat applied directly to the foil by suitable means such
as infrarea, hot air or other heating means,not shown,
15to facilitate and enhance embossing action. Heat may be
applied directly to the material as stat'ed above or by
heating of the embossing rolls 14 and 16 in some
convent'ional fashion of heating, not shown herein.
' The foil material 18 to be embossed is shown
20as coiled in Figure 1 on roll 12 from which it is fed
layered with the resilient buffer material 20 from roll
10 intct~enip of a pair of tangential embossing die-
rollers 14 and 16, the impression roller 14, and the
embossing'roller 16. Both rollers are made of relatively
25hard material. The r:ollers 14 and 16 are driven by
suitable means, not shown, to rotate in the direction
of'the arrows shown' in the drawings. The foil 18 and
; the buffer material 20 pass between the rollers 14 and 16
to pressure-form the foil 18. Take-up r'ollersl24 and 22
30receive and store the embossed foil 28 and the spent
buffer material 26 respectively.
As best seen in Figure 3 and 4, the foil 18 is
- extruded or drawn into the female cavity 30 of the female
impression roller 14 by the raised boss portion 32 of ~,
the male embossing roll 16.
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The depressed portions are made of the con-
- ~Eiguration designed to result in the particular decorative
and structural effect intended for a particular purpose.
Particular care is taken in preparing the
embossing rolls to guarentee that a non-curling foil
is produced at their nip. In order to achieve this, it
is critical that very accurate register is had between
the individual bosses and their complementary female
recesses.
The embossing rolls are made of different
diameters with the male projections on the smaller roll.
The use of a roll o~ smaller diameter to carry the male
die portions is found to achieve improved results over
rolls having equal diameters.
In preparing a pair of rolls, first a steel
roll, preferably the smaller roll, is machined or etched
with the desired pattern as represented in multiple
arrangements of male bosses which protrude from the
; surface uniformly about the periphery of- the roll 16.
The smaller roll is then hardened and tempered. A
second roll 14 of larger diameter is prepared with a
uniformly ground smooth surface. lhe rolls are then
mounted with their axes in a common plane and means, not
shown, are provided for causing the two rolls to meet
at the nip under pressure. The two rolls are rotated
under controlled pressure contact until the pattern of
male protrusions on the smaller roll is duplicated in
complementary re~cesses impressed in the surface of the
larger roll. I
In order to guarantee continued perfect register, I
règistration constancy zones, not shown, which act like
gear drive teeth are provided about the roll peripheries
for a short distance inwardly from the ends of the rolls.
3S These consist of areas of repetitively duplicated bosses
. and recesses which provide the equivalent of a gear
toothed drive and which resemble an embossing pattern
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but which are individually much larger than the bosses
and recesses of the embossing pattern. They act as a
very fine toothed drive mechanism in which back-lash is
practically eliminated, and driving noise and vibration
are held to a minimum.
Extreme care is exercised in transferring the
patterns on the embossing and driving male roll to the
surface of the female roll. -The relative diameters of
the rolls are calculated to insure that the circumferences
of the separate rolls are such that the male and female
portions match evenly with no gaps or improper matching
and registration of any set of recesses
In practice, the foil laminate is fed into the
nip of the rolls at high speed and is driven through
while receiving the desired impression of the pattern
as designed. As stated above,a suitable set of apparatus
of conventional design for applying spring pressure, not
shown, is provided for maintaining adjustably a range of
desired pressures for urging the rolls into contact at
the nip.
Referring now to Pigure 3, it will be seen that
the laminate 18 is advanced in the direction of the arrow
to interlie the bosses and recesses of the nip of the
rolls 14 and 16 The inner wall of the recess 30 is
shown as receiving the yieldable portion 20 of the
laminate 34 which is compressed within the nip provided
: at the line of greatest proximity of the boss 32.
The progressive action of positive perimeter
clamping and subsequent drawing of the foil while bein~
advanced through the nip between the circumferentially
disposed lands of the rolls between the recesses> together
with the localized drawing actian on the foil by the
constantly reducing separation of the dies as rotation
; proceeds, limits the deformation of the foil area to the
. 35 local area of the individual bosses.
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As stated, this yieldable clamping and drawing
action results in localized deformation of the foil.
In effect this establishes the raised pattern without
substantially aberrating the uniformity of over-all
lateral displacement of the sheet of foil area-wise
during the drawing of the individual bosses therein.
The foil is thus protected against undue non-uniform
stress area-wise and physical damage at each boss by
presence of the yieldable layer 20 which cushions and
protects the foil against harsh compressive massaging of
a damaging sort.
In this fashion, a relatively curl-free sheet
is produced which can more accurately and conveniently
be fed through package forming machinery with a minimum
of problems which normally are associated with curling o~
the foil.
~ In Figure 1 of the drawings, there is shown
an alternative method of foil embossing wherein the
foil and yieldable material can feed separately into the
rolls to meet at the nip and therea~ter separate to
produce a sheet of embossed foil in similar fashion to
the method of the present invention last above described.
Having described the preferred mode of carrying
out my invention and bearing in mind that this description
is to be considered for illustrative purposes without
limiting the scope of my invention to the disclosure
made berelD,
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