Note: Descriptions are shown in the official language in which they were submitted.
FIELD OF THE INVENTION
This invention relates to a method and apparatus
for applying contoured elastic ribbon to disposable garments
and, in particular, to applying contoured elastic ribbon to
leg areas of disposable diapers.
BACKGROUND OF THE INVENTION
Use of elastic to improve the fit of reusable
garments or to provide a seal at desirable locations in
reusable garments is well known. Elastic in such garments
is typically sewn in or confined between garment layers in
ei-ther an elongated or relaxed condition. In most cases,
the elastic is affixed on an individual garment by garment
basis.
In disposable garments, such as disposable
diapers, methods and apparatus have been developed to apply
elastic ribbon at high ~abricating speeds by adhering using
an adhesive o~- in some other manner sealing the elastic
ribbon to continuous webs which are subsequen-tly cut into
individual pieces for final use as elements of finished
disposable garments. Because of the need for high speed and
the consequent complexities of applying elastic to the webs,
the elastic is usually applied along a straight line.
Typical arrangements for applying elastic along a straight
line to a web are those shown in Buell UO S~ Patent
4,081,301 and Sabee U~ S~ Patent 4,227,952. In the case of
the Buell patent, the elastic and web substrate are
continuously run at high speed while adhesive is
intermittently applied to the elastic. The elastic and web
are then brought together so that the elastic is adhered to
the web at spaced apart locations~ The web and elastic are
then cut transversely at approximately the midpoint
locations of the unadhered elastic to provide separate
members for use in completing a disposable diaper. The
arrangement used by Sabee entails the folding of the web
substrate and the continuous application of adhesive to the
elastic ribbon. The web and ribbon are then brought
together and adhered to each other, except at the folded
portions of the web. Thus, when the elastic is cut opposite
the folded portions and the web is strai~htened, a
continuous w~b having straight elas~ic only in what will be
the leg portions of a disposable diaper results. The
continuous web then may be cut transversely midway between
the ends of the elas-tic strips to form separate sections for
use in fabricating finished disposable diapers.
Although elastic that is straight relative to a
curved portion of the body along which the disposable
garment is to fit provides a better fit than if no elastic
whatsoever is used, considerably better results can be
obtained if the elastic can be curved or contoured to follow
the body curvature, for example, the curvature of the thigh
and crotch area of an infant when the diaper is being wornO
~lthough some work has been done in this area, to the
inventors' knowledge, very little of the results of this
work is of any practical importance. One example of a prior
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art approach for applying curved elastic to a disposable
garment is illustrated ln the Bourgeois U. S. Patent
3,828,367~ In Bourgeois, a pair of elastic ribbons are fed
to curved grooves in a roll under which a continuous web
passes. As the roll with the ribbons in its grooves goes
over the web the ribbons are ~ransferred in the contoured
pattern of the grooves to the roll. A problem with a
grooved roll for applying elastlc ribbon to a web is that a
groove which is sufficiently deep to guide the ribbon is too
deep to apply a flat elastic ribbon. Because of the better
distribution of stress of a ~lat tensioned ribbon~ a flat
ribbon is preferred in garment elasticization applications.
Also, a curved groove is unreliable insofar as preventing
roping and C-folding of a flat ribbon is concerned~
It is a principle object of this invention to
contour or curve elastic ribbon while it is continously
moving at high speed and being attached to a web that is
also moving at high speed. It is a further object to
accomplish the aforesaid contoured attachment of the elastic
ribbon in a relatively simple and accurate manner.
SUMMARY OF THE INVENTION
According to the invention f apparatus is provided
for continuously moving a web of material and continuously
moving thin elastic ribbon into engagement with and
attaching it to the continuously moving web. The elastic
ribbon is maintained under tension while being continuously
fed into engagement with a roll which is rotatable about its
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axis and which is provided, by oscillating means, with
oscillatory movement. While the rotating roll is thus
oscillating, the tensioned elastic ribbon is passed around a
portion of the circumference of the roll to thereby impart
an oscillatory movement to the ribbon. The oscillating
ribbon is then fed into engagement with the web and assumes
an undulated pattern on the web due to the oscillating
movement of the ribbon. If it is desired to elasticize the
leg areas of disposakle diapers, dual elasticating systems
as described above may be utilized wi~h the oscillations
being such that the elastic ribhons are simultaneously moved
toward each other and away from each other. The continuous
web may then be cut transversely to ~orm separate blanks for
use in fabricating a finished disposable diaper.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of the invention
will appear when taken in conjunction with the accompanying
drawings, in which:
FIG. 1 is a simplified side elevation view
partially in cross-sectionr showing the web supply, elastic
application and elasticized web takeup stations oE the
apparatus of the invention;
FIG~ lA is a side elevation view showlng the
oscillating roll in an alternate position to that shown in
FIG. l;
FIGa 2 is a plan view of the apparatus FIGo l;
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~ FIG. 3 is a plan view of the elasticized web
fabricated with the use of the apparatus and method of the
invention; and
FIG. 4 is a side elevation view of an alternate
embodiment of the inventionO
DETAILED DESCRIPTION OF THE l~lV~N'l'lON
ReferriIlg generally to ~IGS. 1 and 2~ there is
shown apparatus for applying a paix of elastomeric ribbons 4
along a curved line path to a web 42~ Although both of ~he
ribbons 4 and the apparatus associated with each of them is
shown in FIG. 2, only one of the ribbons and its associated
apparatus will be discussed herein since the ribbons and the
apparatu~ for applying each of the ribbons are substantially
identical. Relative to FIG. 1, ~he elastomeric ribbon 4 is
relatively flatr includes a wide surface 5, and has a width
considerably greater than i~s thickness. The ribbon 4 may ~e
supplied in a carton 6 and, if so, it will typically be
natural rubber festooned within the box in such a manner
that it can be pulled, tangle free, from the carton. The
elastomeric rihbon ~ may also be of a synthetic elastomer
such as*"TUFTANE", a thermoplastic polyurethane manufactured
and sold by the l,ord Corpora-tion. In addition to the
elastomeric ribbon 4 being supplied from a c~rton if it is
natural rubber, the ribbon 4, either in the form of natural
xubber or a synthetic elas-tomer, may be supplied from a reel
on which considerable amounts of the ribbon have been wound
to permit continuous, high speed operation. Since, for the
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purposes of this invention, the use of a ribbon supply reel
is not important, it has not been shown. The nip rolls 8
and 8' pull the ribbon 4 from the carton 6 and move it
around idler roll 10 toward the adhesive application station
12. At the adhesive application station 12, the ribbon 4
passes over roll 14O At, or just subsequent to ~he passing
of the ri~bon 4 over the roll 14, hot melt adhesive 18 from
adhesive applicator 16 is applied to the ribbon 4. The
adhesive applicator 16 is located such that the point of
application of the adhesive 18 is a sufficient distance from
the oscillator roll 20 such that the oscillator roll 20 does
not impart lateral oscillating movement to the ribbon 4 at
the point of application of adhesi~e 18 to it. The roll 14,
insofar as its function relating to the application of the
adhesive 18 to the rlbbon 4 is concerned, acts to maintain
the ribbon 4 on a straight line path while the adhesive is
being applied to the ribbon 4 by the applicator 16.
The ribbon 4, with at least one line of adhesive
18 on a wlde surface 5, continues on to oscillator station
22 where it passes around oscillator roll 20. The
oscillating movement of th~ roll 20 causes the ribbon 4 to
also oscillate as the ribbon passes around the roll 20 and
continues on to the chill roll 32 at ribbon application
station 30. The oscillator roll 20 has an axial shaft 24
about which it freely rotates as the ribbon 4 passes in
engagement around it. The oscillator roll 20 also includes
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an oscillating or reciprocating mechanlsm 26 connected to
one of its ends for moving the roll 20 in an oscillati.ng or
reciprocating manner. In the embodiment of FIGS. 1 and 2,
the oscillating motion is in a direction subskantially
parallel to the axial sha~t 24. The oscillating mechanism
may be of a ~ype well-known in the art and consequently will
not be further described herein.
The o~cillating roll 20 may be disposed such that
its axial shaft 24 is not in a horizontal plane and, in FIG.
lA, an oscillating roll 20' is shown which is disposed
substantially vertically relative ~o the side elevation view
of FIG. lA. Note that the elements of FIG. lA are identical
to those shown in FIG. 1 except for those items having a
~Iprime~ designation~ The roll 20' has an axial shaft 24'
and is connected to an oscillating mechanism 26 which
functions to provide oscillatory movement of the roll 201 in
a direction substantially perpendicular to the axial shaft
24' of the roll 20'. As may be seen in FIGo lA, the xihbon
4 rotates 90 as it approaches the roll 20' from the roll
14~ passes around the roll 20' with the wide su.rface 5 of
the ribbon 4 in contact with the roll 20' and continues on
toward the chill roll 32. As in the embodiment of FIGS. 1
and 2, the oscillating roll 20' imparts oscillatory movement
to the ribbon 4 which results in the ribbon 4 moving into
engagement with the web 42 in an undulated pattern~
Referring again to FIGS. 1 and 2, at the web
supply station 38, a continuous length of web 42 is supplied
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from web supply roll 40~ The web 42 passes around idler
roll 44 ~oward ribbon application station 30. ~t station
30, the web 42 engages the chill roll 32 at point 34 and
thereby becomes somewhat chilled prior to engaging the
ribbon 4 at point 36. After their engagement at point 36~
the web 42 and ribbon 4 continue onward together along the
surface of chill roll 32 between the nip formed by chill
roll 32 and nip roll 48. The web 42 and elas~ic ribbon 4
are thereby firmly compressed together after whlch they
continue around and leave the chill roll 32 due to the
drawing force of the take-up drive rolls 28 and 28'.
As may be appreciated, the oscillatory motion
imparted to the ribbon 4 transversely to its length by the
oscillator roll 20 causes the ribbon 4 to engage the web 42
in an undulated pattern. The ribbon 4 is firmly bonded to
the web 42 ~hile in the undulated pattern due to the force
applied to the ribbon 4 and web 42 between the nip of chill
roll 32 and nip roll 480 The engagement of the web 4~ with
the chill roll 32 between points 34 and 36 along the surface
of the chill roll 32 and the engagement of the ribbon 4 and
the web 42 along the surface of the chill roll 32 between
point 36 and the nip at nip roll 4~ pe.rmit the cooling of
the adhesive 18 to thereby avoid burning of the web 42 when
the ribbon 4 and thereby the hot adhesive 18 are firmly
compressed against the web 42 by the nip roll 48.
Re-turning again to the passing of the ribbon 4
around the oscillating roll 20, the velocity of the chill
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roll 32 and nip roll 48 exceeds the velocity of the nip
rolls 8 and 8' ~o thereby stretch the ribbon 4. The extent
of the stretch may vary butr particularly for purposes of
elastici~ing leg areas of disposable diapers, the stretch
should be about 100%. Moreoverl the stretch of the ribbon 4
as it passes around the xoll 20 and the fric-tion between the
surface of the roll 20 and the ribbon 4 should be sufficient
to ensure that the ribbon 4 will closely follow the
oscillating movements of the roll ~0 and thereby provide the
desired undulated pattern of the ribbon 4 on the web 42~ A
100~ stretch of the ribbon 4 is quite adequate in this
regard.
After the web 42 with the ribbon 4 bonded to it
leaves the chill roll 32~ the composite structure may pass
on to the next step in the fabricating of the disposable
garment or, as shown in FIG. 1, the composite web 4~ and
ribbon 4 are drawn through drive rolls 28 and 28' and are
wound on take-up roll 50. It may be noted that the rolls 28
and 28l are driven at a speed sufficient to maintain the
desired stretch in the ribbon 4 determined by the speed of
the rolls 32 and 48 relative to the speed of the rolls 8 and
8'.
With reference now to the embodiment of the
invention shown i.n FXÇ. 4, those elements which function in
substantially the same manner as the elements in the
embodiment of the invention shown in FIG. lA carry the same
identifying numeralsO The web 42 is supplied and the folds
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46 are formed in the web 42 by apparatus such as that
disclosed in U. S. application Serial Number 340,543, filed
January 18, 1982, assigned to the same assignee as the
present inventionl and incorporated herein by reference. In
FIG. 4, the web 42 is carried and continuously moved on
conveyor means 60 which includes a con-tinuous chain 62 and a
plurality of pairs of rollers 64 and 66. As the web 42 is
carried by the conveyor means 60 in the direction shown in
FIG. 4, the folds 46 are formed and maintained in the web 42
between the rollers 64 and 66 by tucker means 68 having
tucker bars 70 which engage the web 42 and move it
downwardly between the rollers 64 and 66 relative to the
view of FIG. 4.
The elastomeric ribbon 4 in FIG. 4 i5 supplied
from a source and driven toward the adhesive application
station 12 in a manner similar to that shown and described
in FIG. lA. Just subsequent to the passing of the ribbon 4
passes around roll 14, adhesive 18 is applied to it by
adhesive applicator 16 at a position such that the
oscillating motion of the oscillator roll 20' do2s not
appreciably move the ribbon 4 laterally of its length at the
point of application of adhesive 18. Of course, if it is
desired that the adhesive 18 have a somewhat undulated path
on the ribbon 4, the location of the adhesive applicator 16
can be moved so that a certain amount of such adhesive
undulation does occur. The ribbon 4 with the adhesive 18
applied then continues on to the oscillator station 22 where
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the ribbon 4 is oscillated by the oscillator roll 20' and
oscillating mechanism 26 in the same manner as previously
descrihed with reference to FIG. lA. The oscillating ribbon
4 with the adhesive 18 applied then continues from roll ~0'
into engagement with the web 42 where it is cooled by
cooling roll 54 which also functions as a nip roll to firmly
apply the ribbon 4 to the web 42. As described in detail in
~n~ n-pa~t 1,181,375, ~ Led ~an~ 22, 1~85 after applicat~ of ~e
elastic ribbon to the web~ the web i5 severed transversely
to form individual leng-ths for use in completing fabrication
of individual disposable diapers.
An apparatus and method for ~roviding a disposable
garment with elastic contoured to fit the shape o the body
on which the garment is worn and thereby provide a better
fit or seal of the garment against the body has been
described. Moreoverp the benefit of this invention may be
obtained while manufackuring sush elasticized disposable
gaxments at very high production speeds.
It will be understood that the foxegoing
description of the present invention is for purposes of
illustration only and that the invention is susceptible to a
number of modifications or changes none of which entail any
departure from the spirit and scope of the present invention
as defined in the hereto appended claims.
