U.S. patent number 3,766,703 [Application Number 05/086,778] was granted by the patent office on 1973-10-23 for process and apparatus for the shape-retaining closure of at least one extremity of a tubular package, especially tampons for feminine hygiene and product produced thereby.
This patent grant is currently assigned to Dr. Carl Hahn KG. Invention is credited to Wolfgang Johst, Stefan Simon, Justus Wolff.
United States Patent |
3,766,703 |
Simon , et al. |
October 23, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
PROCESS AND APPARATUS FOR THE SHAPE-RETAINING CLOSURE OF AT LEAST
ONE EXTREMITY OF A TUBULAR PACKAGE, ESPECIALLY TAMPONS FOR FEMININE
HYGIENE AND PRODUCT PRODUCED THEREBY
Abstract
Process and apparatus for twist closing one end of a tubular
wrapper containing a tampon with a rounded head directed toward the
end of the wrapper being closed and excess tubular wrapper material
extending past the rounded head thereof including axially rotatable
gripper means adapted to grip the marginal portions of the excess
tubular material; means for maintaining the tampon and wrapper
therearound in a substantially stationary condition; means for
rotating the gripper means, gripping the excess tubular material,
relative to the remainder of the tampon and wrapper thereon to form
a twisted end closure and a rosette of twisted excess wrapper
material with a periphery directed away from the twist-closed
tampon; smoothing means including a depression containing member
directed toward the rosette; means for engaging the rosette end of
the twist-closed tampon with the depression including means for
folding the periphery of excess wrapped upon itself toward said
rosette; and means for pressing said rosette toward the rounded end
of said tampon.
Inventors: |
Simon; Stefan
(Moedling/Niederosterreich, DT), Wolff; Justus
(Wuppertal-Elberfeld, DT), Johst; Wolfgang
(Gevelsberg, DT) |
Assignee: |
Dr. Carl Hahn KG (Duesseldorf,
DT)
|
Family
ID: |
5750176 |
Appl.
No.: |
05/086,778 |
Filed: |
December 22, 1970 |
Foreign Application Priority Data
|
|
|
|
|
Nov 5, 1969 [DT] |
|
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P 19 55 600.4 |
|
Current U.S.
Class: |
53/483; 53/370;
53/217 |
Current CPC
Class: |
B65B
51/00 (20130101) |
Current International
Class: |
B65B
51/00 (20060101); B65b 007/12 () |
Field of
Search: |
;53/181,370,3,38,42,217
;19/144.5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Custer, Jr.; Granville Y.
Assistant Examiner: Desmond; E. F.
Claims
What is claimed is:
1. Process of forming an end closure on a tubular wrapped article,
comprising an article having a rear end and a forwardly directed
head with a sleeve of substantially tear resistant material thereon
and folded over the rear end thereof, which sleeve extends
forwardly beyond the article head, which process comprises grasping
the forwardly extending portion of said sleeve, independently
grasping the article and that portion of the sleeve in contact
therewith; twisting the forwardly extending portion of the sleeve
relative to that portion of the sleeve in contact with the article
to form a twisted closure, to conform a part of the forwardly
extended portion of the sleeve to the shape of the head of the
article, to form a rosette forward of the twisted closure and to
maintain the forwardmost periphery of said sleeve in a position
generally normal to the plane of said rosette and reflexing the
outer portion of said rosette toward said article about said
twisted closure after formation thereof.
2. A process according to claim 1 wherein said article is a
tampon.
3. A process as claimed in claim 2, including axially moving the
center of said rosette toward said tampon during said twisting
whereby radially stretching said rosette.
4. A process as claimed in claim 2, including pressing a central
portion of said reflexed rosette together with said twisted closure
toward and against the head of said tampon.
5. A process as claimed in claim 2, wherein said tampon and the
sleeve in contact therewith are maintained substantially immobile
during said twisting.
6. A process as claimed in claim 4, including folding said
forwardmost peripheral portion in the outer portions of said
pressed rosette about said twisted closure, smoothing such together
and heating such whereby to cause shape retention thereof.
7. A process as claimed in claim 2, wherein said forwardly
extending portion of said sleeve has a length of about 90 to 140
percent of the maximum sleeve diameter.
8. An apparatus for forming a sleeve enclosed tampon which
comprises means for receiving a tampon having a sleeve of wrapping
material therearound which sleeve projects forwardly of said tampon
out of said receiving means; means for gripping the forwardly
projecting portion of said sleeve; and means for twisting said
forwardly projected portion relative to the remainder of said
sleeve in contact with said tampon, said means for gripping
comprising a rotatable assembly including centrally disposed
mandrel means, which mandrel means has a smaller diameter than the
inside diameter of said sleeve; pivotable gripper member radially
disposed with respect to said mandrel and operative therewith to
grip and hold said forwardly projected portion of said sleeve
therebetween; means to rotate said rotatable assembly, a control
means associated with said gripper member adapted to move such into
and out of gripping contact with said mandrel and means for
reflexing the outer portions of the so-formed rosette toward said
tampon about the twisted closure after formation thereof.
9. An apparatus as claimed in claim 8, wherein the end of said
mandrel directed toward said tampon has a recess which
substantially corresponds to the shape of the head of said
tampon.
10. An apparatus as claimed in claim 8, wherein said control means
is concentric to the peripheral surface of said mandrel.
11. An apparatus as claimed in claim 8, including means for varying
the gripping force between said mandrel and said gripper member
whereby as the resistance to twisting increases with increased
twisting of said projected sleeve portion, which results from the
leverage ratio between the radius of the twisted closure and the
radius of the mandrel, the projected portion of said sleeve gripped
between said mandrel and said gripper means is axially partially
withdrawn from said gripping toward said tampon.
12. An apparatus as claimed in claim 8, including means for
advancing said gripping means toward said tampon at a rate
proportional to the amount the forwardly projecting portion of the
sleeve shortens by reason of said twisting.
13. An apparatus as claimed in claim 8, wherein said mandrel has
longitudinal grooves on the periphery thereof.
14. An apparatus as claimed in claim 13, wherein the number of said
longitudinal grooves corresponds to the radius of said sleeve in
millimeters.
15. An apparatus as claimed in claim 8, wherein the end of said
mandrel directed toward said tampon head has a circular raised
ridge thereon of a diameter smaller than the diameter of said
mandrel end and concentric with the periphery of said mandrel.
16. An apparatus as claimed in claim 15, wherein the central
portion of said mandrel and said mandrel end, is axially
spring-loaded and is thereby adapted to be forced axially into said
mandrel away from said tampon head.
17. An apparatus as claimed in claim 16, wherein said spring loaded
central portion is rotatable within said mandrel.
18. An apparatus as claimed in claim 16, wherein said spring loaded
central portion is cup-shaped with a peripheral outwardly directed
flange bearing up on a peripheral sleeve portion of said mandrel
under said spring loading.
19. An apparatus as claimed in claim 16, including a spring within
said mandrel surrounding a guide stud projecting therein toward
said spring loaded central portion which stud has a peripheral
shoulder against which said spring bears.
20. An apparatus as claimed in claim 16, wherein said mandrel
comprises sleeve means, supporting means in said sleeve means, said
central portion, a compression spring disposed within said sleeve
between said supporting means and said central portion, ball and
socket mounting means in said supporting means and stud means
engaged to said ball means within said spring means.
21. An apparatus as claimed in claim 20, wherein said central
portion has a circular cone recess in the tampon directed end
thereof.
22. An apparatus as claimed in claim 21, including a raised
circular ridge on said tampon directed end about and forming a part
of said cone recess.
23. An apparatus as claimed in claim 22, wherein said tampon
directed end is champfered from said ridge to the periphery
thereof.
24. An apparatus as claimed in claim 8, wherein said control means
comprises a cylinder partially coaxially surrounding said twisting
means and cam control means engaging said cylinder in an axially
movable relationship.
25. An apparatus as claimed in claim 24, including gripper members
pivotably mounted in engaging relation to the periphery of said
mandrel and lever arm means extending from said gripper members
engaging said cylinder which members and arms are disposed
equiangularly about the periphery of said mandrel.
26. An apparatus as claimed in claim 8, further including smoothing
means spaced from said twisting means.
27. An apparatus as claimed in claim 26, wherein said smoothing
means includes a smoother shaft disposed substantially parallel to
said twisting means, a heatable smoothing head on said smoother
shaft directed toward said tampon and means for moving the twisted
closure of said tampon against said smoothing head.
28. An apparatus as claimed in claim 27, wherein said smoothing
head is recessed substantially corresponding to the shape of said
tampon head.
29. An apparatus as claimed in claim 26, including common means for
simultaneously axially reciprocating both said twisting means and
said smoothing means.
30. An apparatus as claimed in claim 26, including a common drive
means for turning both said twisting means and said smoothing
means.
31. An apparatus as claimed in claim 26, including rotatable
indexing wheel means containing a receiving means for tampon and
sleeve prior to twisting such, means for turning said wheel in a
plane substantially perpendicular to the axis of said twisting
means and the axis of said smoothing means and means for bringing
said receiving means into operative engagement sequentially with
said twisting means and said smoothing means.
32. An apparatus as claimed in claim 31, having a plurality of said
receiving means disposed equiangularly about the periphery of said
indexing wheel.
33. An apparatus as claimed in claim 32, including tampon gripper
means associated with each receiving means and with the tampon and
sleeve therein and cam means associated with and engaged to said
tampon gripper means operative to move said tampon gripper means
into and out of engagement with the tampons in said receiver
means.
34. An apparatus as claimed in claim 33, wherein said cam is so
constructed and arranged as to cause said tampon gripper means to
engage and hold said tampon and sleeve substantially stationary
when such is engaged with said twisting means and so as to cause
said tampon gripper means to permit only axial movement of said
tampon and sleeve thereon which is engaged with said smoothing
means.
Description
This invention relates to tampons. It more particularly refers to
tubular enclosures for tampons and still more specifically to end
closures therefor.
It is known to use tubular wrapping material for encasing a tampon.
It is known to use a tubular wrapper of pliable, tear-resistant
material, such as cellophane, or other plastic films, to envelope a
tampon. One end of these tubular wraps, the rear end, suitably has
a folded closure.
Difficulties have been encountered however in forming a suitable
closure for the rounded head end of a tampon, particularly a tampon
which is relatively elastic and has a tendency to expand and in
which the tubular wrapper extends and projects an open extremity
thereof beyond the rounded head of the tampon.
The invention is addressed to the problem of creating a closure of
the open extremity of a tubular wrapper for elastic products having
a tendency to expand axially and at the extremities, and in some
cases in all axial directions, preferably tampons of pressed fiber
material for feminine hygiene, the end closure must, due to its
special folding geometry, be tight and stable in shape. Such
products require a prescribed shaping of the wrapping material as
it is turned in or twisted, in order to prevent unsightly wrinkles
that might emboss the product, and to insure that the closure will
provide the best possible seal.
Accordingly, one aspect of this invention resides in a process of
forming a twisted end closure of a tubular wrapping sleeve
containing a tampon with its rounded head directed toward an open
end of the wrapping sleeve from which the end closure is to be
made, which process comprises holding the tampon and the sleeve
directly in contact therewith in a relatively fixed position;
gripping the open end of the tubular material, which extends out
from the tampon head a given predetermined amount, with a rotatable
and axially movable, relative to the tampon and sleeve thereon,
gripping means; rotating the gripping means and that portion of the
tubular material gripped thereby relative to the tampon and to the
remainder of the tubular sleeve material in contact with the
tampon, whereby to twist the open end of the tubular material into
a twist closure close about the tampon head, to form a rosette of
the remaining tubular material on the side of the twist closure
away from the tampon head and to form a periphery of untwisted
tubular material extending away from the tampon and the twist
closure; engaging the untwisted periphery of the tubular material,
rosette and twist closure with an axially displaceable, possibly
heating, smoothing means having a recess which substantially
matches the tampon head; axially moving the smoothing means toward
the tampon whereby inwardly folding the periphery of tubular
material and the rosette toward the tampon head while crushing the
twist closure; and fixing such in said position.
The projecting open extremity of the sleeve-like tubular wrapper is
seized at the inside and outside of its outer margin with the
substantial retention of its diameter, and is then shaped by a
rotation coaxial to the long axis of the wrapper into a twisted
constriction, while its outer extremity is shaped into a flat
rosette. By shaping the outer extremity of the wrapper into a flat
rosette a certain self-locking effect is achieved in regard to the
twisted constriction because the folds that develop are pressed
against one another and crimped together to a certain extent. In
this manner an unintentional undesired rotation of the rosette by
unwinding to cause an opening of the twisted constriction is
prevented. On the other hand, the flat rosette offers a good grip
for the easy opening and removal of the product by the ultimate
user without damage thereto. This advantage is particularly
important in the case of a menstruation tampon that is provided
with a round head end, for example.
This invention provides that, as the resistance which the twisted
constriction, as it forms, offers to the further twisting of the
extremity of the wrapper increases, the wrapper extremity is drawn
toward the tampon, approximately coaxially to the constriction, and
at the same time the bottom of the rosette that is forming is
stretched radially from the constriction.
A further aspect of this invention consists in re-flexing the flat
bottom of the rosette as formed, prior to the end of the twisting
process, so that it extends partially back over the constriction
toward the tampon's rounded head. This substantially improves the
cross-shrinkage of the creases that form in the bottom of the
rosette and the self-locking action produced thereby.
Depending on the wrapping material used and on the dimensions of
the product, a further improvement can be achieved according to
this invention, by pressing a central portion of the reflexed
rosette bottom, whose diameter is smaller in size than that of the
tubular wrapper together with the twisted constriction, against the
product in the wrapper, that is the tampon. The wrapper periphery
is shortened by further turning of the gripped outer margin of the
wrapper in relation to the outer margin of the center portion of
the rosette bottom which is pressed against the product, for the
purpose of forming a cylindrically projecting margin on the
rosette. In this manner only the margin of the rosette bottom that
is outside of the pressed center portion of the rosette bottom that
is outside of the pressed center portion is subjected to tensile
stress, and at the same time, the constriction is protected.
During the twisting of the open end of the wrapper, it is desirable
to hold the wrapper and the tampon contained therein securely
against rotation and axial displacement.
Another important improvement according to this invention can be
achieved if the cylindrical, projecting margin of the rosette is
folded down onto the outer surface of the rosette bottom facing
away from the constriction, and is smoothed together with the
rosette bottom and the twisted constriction against the portion of
the wrapper than envelopes the extremity of the product in a
tightly form-fitting manner. This can be done with the application
of heat in order to fix the end closure shape to the shape of the
tampon head. When the rosette is smoothed against the corresponding
extremity of the product, it is desirable to hold the wrapper and
product so that they will not rotate, but to give them a slight
axial displacement. In this manner slight differences in the length
of the product can be accommodated.
It is advantageous to use a wrapper whose open extremity projects
beyond the corresponding extremity of the product by a length
corresponding to about 90 to 140 percent of the greatest diameter
of the tubular wrapper.
The invention furthermore provides for an apparatus for the
performance of the above-named process, which is characterized in
that an axially reciprocatable and rotatable twisting device is
composed of at least one clamping member and a mandrel whose end
face configuration and recess is made to match the shape of the
extremity of the product that it faces, and whose cross-sectional
dimensions are somewhat smaller than the greatest diameter of the
tubular wrapper. The clamping member is designed to be movable by
means of a controlling device in relation to the peripheral surface
of the mandrel disposed coaxially to the axis of rotation of the
twisting device.
For adaptation to the thickness of the wrapping material and to the
forces required for the production of the twisted constriction,
provision can furthermore be made so that the clamping force of the
clamping member is variable and is of such magnitude that, with the
increase of the resistance of the tubular wrapper resulting from
the leverage ratio between the radius of the twisted constriction
and the radius of the mandrel, the open extremity of the wrapper
can be partially withdrawn axially from the position in which it is
clamped.
An additional measure that is important in the packaging of mass
goods is that, during the rotating movement of the twisting device,
its positively controlled axial advancing movement in the direction
of the product in the tubular wrapper is of a magnitude that is
proportional to the shortening of the projecting end of the wrapper
brought about by the formation of the twisted constriction.
This measure is of substantial assistance in assuring that the
twisted constriction is always formed under uniform tension of the
wrapping material with its adjoining flat rosette.
Since a uniform folding geometry is important to the twisted
constriction closure of the invention, it is possible according to
a further embodiment of the invention to provide the periphery of
the head end of the mandrel with grooves extending in its
lengthwise direction. In this manner, creases are formed in the
tampon and wrapper where the grooves are located on the mandrel. It
is particularly advantageous and preferred if the number of grooves
corresponds to the number of millimeters in the radius of the
tubular wrapper.
A still further improvement can be achieved if a pressing means in
the form of an annular ridge, whose diameter is smaller than that
of the entire end face of the mandrel, projects axially from the
said end face. In this manner it can be brought about that during
or after the formation of the twisted constriction, the wrapping
material extending from the mandrel to the twisted constriction is
relieved of tension since only the wrapping material that is
outside of the annular ridge is subjected to the forming action in
the final phase of the production of the twist closure with the
flat rosette.
It is desirable for a larger, central portion of the end face of
the mandrel to form a pressing member which is desposed so that it
can be pushed coaxially back into the mandrel sleeve against the
action of a compression spring to a limited degree and is freely
rotatable in relation to the mandrel sleeve. This makes it possible
to compensate for tolerable differences in the position of the
product within the tubular wrapper so that the quality of the
twisted closure with its flat rosette will always be uniform
regardless reasonable variations in the length of the open end of
the tubular wrapper projecting beyond the corresponding end of the
product.
In this embodiment, the recessed portion of the pressing member
normally projects from the mandrel sleeve, and it has an annular
shoulder that is urged by the compression spring against an
internal annular shoulder on the mandrel sleeve. One end of the
said compression spring bears against the pressing member and the
other end encompasses a guiding stud inside of the mandrel and
bears against an annular shoulder on the said stud. This guiding
stud is preferably guided axially and freely rotatably within the
mandrel sleeve. It is urged by the compression spring against a
ball engaging its center, which ball partially protrudes from a
central recess provided in the corresponding end of the
mandrel.
When the pressing member is in the normal position, its end face
and the end face of the mandrel sleeve together form the mantle
surface of an obtuse circular cone, a champfer. Advantageously, the
pressing ridge mentioned above is formed by the line at which the
circular conical surface of the pressing member meets an obtuse
circular conical recess in the end face of the pressing member. The
circular conical surface on the extremity of the mandrel thus aids
the slipping of the wrapping material from the mandrel and at the
same time makes it possible to form the pressing ridge in a simple
manner.
In a further development of the invention, it is desirable to
construct the controlling means for the twist closure and rosette
forming means in the form of a control cylinder which coaxially
partially envelops the twisting device and is axially displaceable
with respect to the twisting shaft under the control of a cam. The
lever arms of a plurality of grippers are held in engagement with
an annular shoulder on the control cylinder by the action of
springs, while the pivot points of the said lever arms are arrayed
at equal circumferential distances in a common plane normal to the
twister shaft on a portion of the twister shaft.
A smoother shaft can be and preferably is mounted at a distance
from and parallel to the twister shaft on the same overall machine
frame. The said smoother shaft has a heatable smoothing station on
the indexing wheel for smoothing and folding down the tubular
wrapper. This arrangement makes it possible to provide a common
advancing apparatus both for the control cylinder for the twisting
shaft and for the smoothing head, by means of which the axial
reciprocation of these members towards and away from the wrapper
can be derived. Furthermore, it is possible in this manner to
provide a common rotatory drive for the twister shaft and a
smoother shaft.
The delivery of the tubular wrappers containing the product can be
accomplished by means of an indexing wheel which is rotatably
mounted in a plane perpendicular to the twister shaft and to the
smoothing shaft. The indexing wheel is provided with receivers for
the tampons and wrappers thereon at equal intervals on its
periphery, one receiver being provided at each index position of
the indexing wheel: one in a position in which the tubular wrappers
are fed in, one coaxial with the mandrel of the twisting device,
and one coaxial with the smoothing shaft.
It is at the same time desirable to associate with each receiver a
gripping plunger which is adjustably joined to a cam follower, each
gripping plunger being movable radially outward by a stationary cam
into the receiver against the force of a spring, when the indexing
wheel is rotated. In this manner, each wrapper with the product it
contains can be held substantially in the desired position during
the twisting and smoothing processes. It is desirable to design the
cam in such a manner that, during the twisting process, the wrapper
that is in the twisting station and the product which it contains
are not either axially or radially movable in the receiver or
twistable, of the indexing wheel, and the one that is in the
smoothing station is movable only axially.
Understanding of this invention will be facilitated by reference to
the accompanying drawing in which:
FIG. 1 is a partially sectioned elevation of the apparatus hereof,
which has an indexing wheel bearing receivers for tubular
wrappers.
FIG. 2 is a side view with parts in section of the indexing wheel
of FIG. 1 with its drive means and the indication of a twisting
device.
FIG. 3 shows a schematic view of the twisting device of this
invention with the grippers thereof opened and a tubular wrapper
placed coaxially opposite them partially in section.
FIG. 4 shows the twisting device partially in section of FIG. 3 in
an advanced position in which the grippers and mandrel are about to
engage the open end of the tubular wrapper.
FIG. 5 shows the twisting device partially in section of FIG. 4
with the tubular wrapper engaged by the grippers and mandrel.
FIG. 6 shows the twisting device partially in section of FIG. 5
advanced in the process to where a twisted rosette has been made
from the end of the tubular wrapper.
FIG. 7 shows the twisting device partially in section FIG. 6 after
the pressing motion of the mandrel in the direction of the tubular
wrapper and after the opening of the grippers.
FIG. 8 shows a smoothing head partially in section opposite a
package bearing a twisted rosette, in its starting position after
leaving the operation shown in FIG. 7.
FIG. 9 shows the smoothing head partially in section of FIG. 8
before the beginning of the smoothing of the twisted rosette.
FIG. 10 shows the smoothing head partially in section of FIG. 9
with the twisted rosette smoothed against the packaged product.
FIG. 11 shows the indexing wheel of FIGS. 1 and 2 partially in
section in a partially cut-away view.
FIG. 12 is a vertical section taken along line XII--XII of FIG. 11
looking in the direction of the arrows.
FIG. 13 is a longitudinal cross-section of another embodiment of a
mandrel according to this invention.
The drawings represent an apparatus for the shape-retaining closure
of the open extremity 15a of a tubular wrapper 15 of formable,
tear-resistant material, such as cellophane, enveloping a product
in the form of a tampon 16 for feminine hygiene. The open extremity
15a of the tubular wrapper extends beyond the head end of the
tampon for a length amounting to about 90 to 140 percent of the
greatest diameter of the tubular wrapper. The tubular wrapper is
already closed at its rear end, at 15b (FIG. 3), by folds made
perpendicularly to its long axis. The tampon consists of a fiber
batting which is wound on itself and is compressed radially to the
desired final diameter of the tampon. The head end 16a of the
tampon is rounded. The tampon is provided with longitudinal
indentations 16b, 16c, 16d, 16e, preferably located at equal
intervals around its circumference (FIG. 11). At the rear end the
tampon is equipped with a recess 16f in whose plane at right angles
to the long axis of the tampon a removing string 17 is lodged in
the form of a flat spiral.
The margin of the open extremity, 15a of the tubular wrapper 15 is
gripped inside and outside by a twisting means 18 while
substantially retaining its diameter, and then it is formed, by
rotation coaxial to the long axis of the wrapper, into a
constriction 15e, and at its outer extremity, into a flat rosette
15c (FIGS. 1, 6, and 7). While the twisted rosette 15c is being
released by the twisting means 18, the latter presses the rosette
in the direction of the rounded head 16a of the tampon, as shown in
FIGS. 6 and 7. By this action, as shown in FIG. 6, the at first
flat bottom 15d of the twisted rosette is reflexed over the twisted
neck 15e. During the twisting of the open end of the tubular
wrapper, the latter and the tampon it contains are fixedly held
unrotatably and axially undisplaceably in position. Then the outer
extremity of the tubular wrapper, which forms the twisted rosette
15c, is smoothed against the rounded head 16a preferably with the
application of heat, and is fitted to the shape of the rounded head
(FIGS. 8 to 10). The outer, approximately cylindrical margin 15f
(FIGS. 8 and 9) of the twisted rosette 15c is folded inwardly upon
itself (FIG. 10) approximately concentrically with the long axis of
the tubular wrapper when the rosette is being smoothed against the
rounded head of the tampon. The tubular wrapper 15 with the tampon
is held during this latter operation so that it will not rotate,
but is displaced axially to a slight extent, so that the absorbent
fiber material of the tampon will preserve its prescribed density
in the area of its rounded head. The tension with which the wrapper
is applied to the tampon after the twisting of its open extremity
can be controlled to a great extent by the number of rotations of
the twisting device, so that the quality of the tampon is preserved
even when the open end of the tubular wrapper is twisted.
The tubular wrappers 15 with the tampons 16 are delivered to a
twisting station 19 and a smoothing station 20 (FIG. 2) by means of
an indexing wheel 21 which is provided with receivers 21a which are
positioned with their axis parallel to the axis of rotation of the
indexing wheel and are spaced at equal intervals about the circular
wheel. The receivers 21a are provided with apertures 21b (FIG. 1)
whose cross-section corresponds approximately to the cross-section
of the tubular wrappers with the tampons contained therein. On the
side of the receivers directed away from the twisting device 18,
there is provided a stop plate 22 spaced a short distance from the
indexing wheel, in a plane parallel to the latter. This stop plate
22 must be provided at least at the twisting station and at a
feeding station 23 (FIG. 2) in which a tubular wrapper 15 with
tampon 16 therein is fed to the indexing wheel by means of a feed
wheel 24 (shown partially cut away in the drawing) via axial
insertion thereof into an appropriate receiver 21a.
The indexing wheel 21 is stepwisedly advanced one position at a
time, corresponding to the number of receivers 21a, through a drive
means 25, preferably a chain drive which is driven from a cam 26,
preferably a Maltese cross cam, which cam 26 is itself driven by a
motor means 28 through a suitable conventional driving means 27,
such as an endless belt.
A mandrel 29 (FIG. 1) of the twisting device 18 is positioned
coaxially to and at a distance from the receiver 21a that is
situated at the twisting station 19 (FIG. 2). The mandrel has a
diameter that is slightly less than the inside diameter of the open
extremity 15a of the tubular wrapper 15. The end of the mandrel 29
directed toward the receiver 21a has an arcuate socket-like recess
29a which substantially matches the rounded head 16a of the tampon
16.
The peripheral surface of the receiver directed end of mandrel 29
has grooves 29b, (shown in FIG. 1 but omitted from the other
Figures for purposes of clarity and simplicity) extending
longitudinally thereon from the receiver directed end thereof. It
is preferred to relate the number of grooves 29b to the radius of
the tubular wrapper 15; for example, six grooves 29b are provided
in a mandrel used in conjunction with a tubular wrapper having a
radius of 6 mm, eight grooves 29b are provided in a mandrel used in
connection with a tubular wrapper having a radius of 8 mm, etc.
One particular embodiment of a mandrel 29 which has been found to
be especially well suited to this invention is shown in FIG. 13.
This mandrel has a spring-loaded 82 central portion 81 containing a
conical recess 81e. The tampon directed end of the central portion
81 has a pressing ridge 81b which is formed between the recess 81e
and a champfer 81c about the periphery of the mandrel. The mandrel
central portion 81 is in turn surrounded by a mandrel sleeve 80
whose tampon directed end is champfered to correspond to and mate
with the champfer 81c. The mandrel central portion 81 and the
mandrel sleeve 80 have abutting surfaces 80a and 81d which bear
against each other by reason of the spring loading on the mandrel
central portion. A compression spring 82 is provided within the
mandrel bearing upon the surface 81a of the mandrel central portion
directed away from the tampon and bearing upon a tampon directed
annular surface 83a of a guiding stud 83 mounted within a recess in
the mandrel. The guiding stud forms a core or shaft within the
coils of the compression spring 82 and is itself compression
mounted to the mandrel through a ball 84 which sits in a recess 80b
in the tampon directed end of the mandrel. A blind hole 83c in the
stud 83 serves to mount the ball 84 such that the stud 83 if freely
rotatable.
The mandrel 29 is shown in FIG. 1 and is housed in a control
cylinder 37 which is coaxially fastened at its rear extremity to a
cylindrical member 30 which is itself coaxially affixed to one end
of a shaft means 31 through a nut 32 (FIG. 1). Recesses 33 extend
radially from the mandrel 29 at equal peripheral intervals. There
are disposed in such recesses 33, in a plane normal to the shaft
31, fulcrum pins 34 on which outer wrapper grippers 35 are
pivotably mounted. These grippers are mounted to pivot in generally
radial planes.
The wrapper grippers 35 have lever arms 35a extending radially
outward by therefrom approximately in the plane of the fulcrum pins
34. The gripper edges directed towards the tubular wrapper are
urged against an inner annular shoulder 37a of the control cylinder
37 by the pressure of springs 36. The wrapper grippers 35 are
pressed against the tubular wrapper 15 and mandrel 29 with a
constant pressure determined by the characteristic of the springs
36. When a wrapper 15 is held by the mandrel, there is a slight gap
between the gripper lever arms 35a and the control cylinder
shoulder 37a during the twisting process.
The shaft which provides the twisting operation of this apparatus,
shaft 31, is provided at its end opposite to the mandrel containing
end, with an axially non-displaceable but freely rotatable collar
38 which has two diametrically opposite pins, one of which can be
seen in FIG. 1 and is identified as 39. These pins are engaged by
the forked ends of lever means 40 rotatable about an axle 79, which
lever means is provided with a cam follower 41 which, under the
action of a tension spring 42, rolls on a cam 43. The twister shaft
31 is positioned within a sprocket wheel 54 with the hub 31a
disposed rotatably but axially non-displaceably within a frame 44.
The twister shaft 31 is axially displaceable within hub 31a and
sprocket wheel 54.
The frame 44 has apertures 46 therein through which guide rods 45
and 45a extend freely. These guide rods join the control cylinder
37 to plate 47 disposed on the side of the frame directed away from
the index wheel 21. The plate 47 is longer than the space between
the guide rods 45 and 45a and extends past such rods into the
vicinity of a shaft 63 to which it is also attached. There are
provided at the end of the plate 47 near the shaft 63 two
diametrically opposed pins 48 (only one is shown in FIG. 1) which
engage a forked operating lever 49 which is pivotable about an axle
50. The operating lever 49 is biased by a tension spring 54 to
bring a cam follower 52 into engagement with a rotatable cam 53
whereby to move the plate in such a manner that the rods 45 and 45a
and the shaft 63 move axially.
The twister shaft sprocket 54 is connected by a chain 55 to another
sprocket 56 attached to a pinion 57 which meshes with a toothed
segment 58. The toothed segment 58 is pivotable about an axle 59 on
which a lever 60 is fastened, which by means of a cam follower 61
follows a cam 62.
The sprocket 56 and the pinion 57 are disposed in the frame 44 so
as to be rotatable but axially non-displaceable. The shaft 63,
which is mounted in the frame 44 and is axially displaceable within
pinion 57 through the bore of the sprocket 56, is provided with a
smoothing head 64 on its index wheel directed end.
The smoothing head 64 as shown in FIGS. 1 and 8 through 10 has, at
its tampon divided end, a shaft 64a terminated by a forming member
65, which can be heated by an electrical resistance heating element
66, contained in the shaft 64a. The heating element 66 is connected
by electrical conductors 67, 67a, inside of the hollow shaft 63 to
slip rings 68, 68a affixed to the shaft 63 which are in turn
connected through conventional carbon brushes 69, 69a, to a
direct-current source of electricity. The forming member 65 is
provided in its tampon directed end face with an arcuate recess
65a, which is somewhat larger in diameter than the end of the
tubular wrapper 15 which it faces, and is of substantially the same
shape as the tampon end to which it is directed. The movement of
the operating lever 49 thus makes it possible, by means of the
plate 47, to produce a common axial movement of the control
cylinder 37 and the smoothing head 64, controlled by the cyclic
movement of the cam 53.
As shown in FIGS. 11 and 12, radially extending tampon grippers 70
are associated with each receiver 21a in the indexing wheel 21, and
are operatively engaged in each case with a cam follower 71 in such
a manner as to be adjustable in length. This adjustment is
performed by means of a screw-threaded joining means 72 between the
gripper and the cam follower. An adjusting nut 73 is affixed
rotationally to the cam follower and is biased by a compression
spring 74. The other end of the compression spring 74 bears upon an
external annular support collar 21b of the indexing wheel. The
adjusting nut 73 can be locked in its rotational position by a set
screw 75 which conventionally engages the recesses 75a provided on
the external periphery of the adjusting nut 73. An internally
threaded shank 70a of the tampon gripper 70 passes through the
annular support 21b into engagement with the adjusting nut 73 and
each cam follower 71 passes through an aperture in an inner annular
support 21c and into engagement with a stationary cam 77 which is
affixed to the machine housing coaxially to a drive shaft 78. In
the upper portion of FIG. 12, the cam follower 71 is urged radially
outward by the cam 77 against the action of the compression spring
74, in such a manner that the tampon gripper 70 engages in a
longitudinal embossed groove 16d in the tampon 16 while
simultaneously deforming the wrapper 15 to conform to this groove.
The face of the tampon gripper 70 is wedge-shaped to match the
cross-sectional shape of the embossed groove 16d. The shape of the
cam 77 is so designed that during the twisting procedure at
twisting station 19 (FIG. 2 ) the tubular wrapper with the tampon
therein can be moved neither radially nor axially, and at the
smoothing station 20 it can be moved only radially.
The operation of the above-described apparatus is substantially as
follows:
At the beginning of an operation or a complete segment of a
continuous operation, the action of the cam 43 pivots the lever 40
about axle 79 and thereby advances the mandrel 29 with the wrapper
grippers 35 axially towards the open extremity 15a of the tubular
wrapper 15. Since at this moment the control cylinder 37 is
stationary, the wrapper grippers 35 are opened against the action
of compression springs 36 by this advancing movement. The control
cylinder 37 remains in its starting position until the open
grippers have reached the position shown in FIG. 3 at a given
predetermined distance from the open end 15a of the tubular wrapper
15.
Then the control cylinder 37 is advanced toward the index wheel 21
by the action of the cam 53 on the operating lever 49 through the
cam follower 52 to the plate 47 initiates. The control cylinder 37
advances at a rate which is substantially the same as the rate of
advance of the twister shaft 31 by reason of the action of the cam
43 as aforesaid. As a result, after an initial movement of the
twisting means 18, it and the control cylinder 37 are advanced
together towards the tubular wrapper. The movement of the twister
shaft and twisting device by cam 43 is concluded as soon as the
mandrel 29 has been introduced to a predetermined depth about 3 mm,
into the open end of the wrapper 15 (FIG. 4). Then the control
cylinder is further advanced by the action of the cam 53 until the
wrapper grippers 35 apply their gripping surfaces to and grip the
outer margin of the open end 15a of the wrapper 15 and clamp such
against the cylindrical periphery of the mandrel 29 (see FIG.
5).
The cam 62 then immediately initiates the rotatory movement of the
twister shaft 31 and twisting device through the lever 60, toothed
segment 58, pinion 57 and chain 55. During this rotation the open
end 15a of the tubular wrapper 15 is closed by twisting (see FIG.
6). In order to compensate for the amount by which the open end of
the tubular wrapper is shortened by the twisting process, the
twister shaft 31 and twister are advanced together with the control
cylinder 37 during the twisting process in a positive manner
according to the design of the cams 43 and 53, so that the
extremity of the wrapper 15a which is gripped between the mandrel
29 and the gripping surfaces of the wrapper grippers 35 cannot
escape therefrom (FIG. 6). The control cylinder 37 is held in the
position which it has by this time assumed by the cam 53, while the
cam 43, by means of the twister shaft 31, moves the mandrel 29 and
wrapper grippers 35 a little further towards the tubular wrapped
and now closed tampon 16. In this manner the wrapper grippers 35
are opened against the action of the compression springs 36, while
at the same time the slight forward movement of mandrel 29 reflexes
the twisted rosette 15c that has formed by the twisting, bending
its bottom 15d towards the rounded head 16a of the tampon (FIG.
7).
The twister shaft 31 together with the mandrel 29 and the wrapper
grippers 35 are then moved back along with the control cylinder 37
to the starting position shown in FIG. 1. The control cylinder 37
comes to a stop shortly before the twister shaft 31 with the
cylindrical member 30 and mandrel 29, so that the wrapper grippers
35 close again. After this the indexing wheel 21 advances one step,
whereupon the next twisting process can begin. The tampon
containing wrapper 16a, now provided with the twisted rosette and
closure 15c transferred from the twisting station 19 to the
smoothing station 20 (FIGS. 1, 2, 8 and 9). In this smoothing
station 20 the smoothing head 64 is pressed, by the action of the
cam 53, in synchronization with the movement of the control
cylinder 37, against the twisted rosette 15c, and is simultaneously
rotated; as a result, the cylindrical outer margin 15f of the
twisted rosette is folded inwardly, and the rosette together with
the twisted constriction 15e is smoothed into a form-fitting
configuration around the head 16a of the tampon as a result of the
heating action (FIG. 10).
Another twisting process of another wrapped tampon is being carried
out in the twisting station 19 at the same time as this described
smoothing operation is being carried out.
The operation of the mandrel 29 in the embodiment shown in FIG. 13
differs from that described above with respect to a mandrel with a
non-spring loaded central portion in that, as soon as the pressing
ridge 81b presses the bottom of the rosette 15d (FIG. 6) against
that portion of the material covering the rounded head 16a of the
tampon, the folding geometry is created again radially outside of
this pressing ridge 81b. Since the radius of the pressing ridge 81b
is substantially greater than that of the twisted constriction, the
leverage ratio that is operative in the twisting action is
diminished, so that the pulling of the rosette from the mandrel is
accelerated. At the same time the folds that are formed are secured
against one another by the pressing ridge in the shape in which
they are formed, so that a mutual interlocking of the folds is also
achieved in the area of the pressing ridge. It is particularly
important that, after the rosette bottom has been secured by the
pressing ridge 81b, the continued twisting forces no longer affect
the interlocking of the folds running into the twisted
constriction, so that the axial advancement of the mandrel secures
them together in the folding geometry which they already have, or
they are firmly interlocked with one another by the reflexing of
the rosette bottom. At the same time, the embodiment of the mandrel
shown in FIG. 13 makes possible compensation for differences in the
length of the open open extremity 15a of the tubular wrapper
projecting beyond the head of the tampon caused by acceptable
variations in manufacturing.
It can be seen that in this manner a shape-retaining and stable
twisted closure adapted to the deformability or delicacy of the
product can be achieved, along with a pressing and smoothing
action. Under certain circumstances the heating of the smoothing
head can be dispensed with.
* * * * *