Note: Descriptions are shown in the official language in which they were submitted.
834Z
The present invention relates to apparatus and
methods for manufacturing tampons for the absorption .
of body fluids, particularly vaginal tampons.
Highly absorbent gel material such as modified
celluloses and starches and polyacrylonitrile materials
have been proposed for use in tampons, however it is
difficult to ensure that during manufacture the materials
are located and maintained in the correct position within
the tampon, and also it is difficult to arrange for the
j 10 best utilisation of these materials during conditions
of use. A possible construction of tampon satisfying -
these requirements is in~ofim~.of an annular bag of
thin fluid pervious material enclosing a sleeve shaped
layer of absorbent material.
The present invention aims to provide a method and
apparatus for manufacturing such a tampon.
~ ~cor~ingly the present invention provides a method
of manufacturing a sleeve shaped tampon compD~ing forming
a layer of absorbent material, applying said layer as a
sleeve on to a hollow end portion o~ an elongate mandrel
to a length correpponding to that of the tampon, applying
a fluid pervious layer over said absorbent material
layer so as to completely cover said abeorbent material
layrr and have a portion extending at least said length
beyond the end of said mandrel, and applying a force to the
exterior of said extending portion to cause it to introvert
into the~h~llow end portion of said mandrel, and removing
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the resultant annular bag shaped tampon from said
mandrel.
An external probe or an air jet may be applied as
the external force.
An alternative is to apply a vacuum from within
the hollow to induce an atmospheric force on the
exterior. In neither case however is it necessary
or desirable to attach anything, such as a drawstring,
to the material at th~t stage.
It should be noted that in US Patent 3 712 305 a
method is proposed where a string is applied up the centre
of the mandrel to the interior of the extending layer.
However this requires two string tying stage, and also
makes it impossible to operate a continuously running
system, since the string for each successive tampon has
to be separately fed into thehhollow-mandrel.
A further advantage of not t~ing the extending -~
portion is that after it has been introverted lt can
revert to a substantially cylindrical form parallel to
the overlying layer, and thus a neater finished article
can be produced.
The inventiqn also ~ rovides an apparatus for forming
a tampon comp~aing an elongate mandrel having a hollow
end, means for feeding a layer of absorbent material
onto the hollow end of said mandrel to form a sleeve
having a length corresponding to that of the tampon,
means for feeding a fluid pervious layer over said
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absorbent material layer so as to completely cover said
absorbent material layer and have a portion extending
at least the saoe length beyond the end of said mandrel,
and means for applying a force to the exterior of said
extending portion to cause it to introvert into the
hollow end of sa~d mandrel. Preferably said force
applying means is -aia ~ir jet directed into the hollow
of said mandrel or applies a vacuum within the hollow
mandrel to induce ~tmospheric pressure on the exterior.
The layer of absorbent material may be formed from
a sheet of a composite absorbent, or by sandwiching
absorbent material within a pair of carrier layers.
The layer may then be in single, double, treble or
fourfold form.
An embodiment of the invention will now be described
by way of example with reference to the accompaaying
diagrammatic drawings in which:-
Figure 1 is a schematic diagram of an equipment
for making a sandwich of tissues
inaorporating absorbent gel;
Figure 2 is a pers~ective view showing how the
sandwich and an outer layer are formed
on a mandrel;
Figure 3 is a view of the end of the mandrel
showing formation of the tampon;
Figure 4 is a similar view to Figure 3 at a
different operational stage; and
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Figure 5 is a diagrammatic representation of
the tampon so formed.
Referring to Figure 1 a hopper 1 contains a
suitable highlyaabsorbent milled particulate cross-
linked carboxyalkylated starch derivative gel. A
vibratory fe~der 2 is arranged to feed this gel material
into the nip of a pair of rollers 3, 4 of which the upper
roller 3 is of steel and the lower roller 4 of rubber so
as to accommodate variations in the size or evenness of
the particle layer.
Also feeding into the nip of the rollers 3, 4 are
two layers of tissue carrier material 5, 6 supplied
from supply rolls~ 7, 8 via intermediate feed rollers 9.
In each case a water spray device 10 is provided whieh
wets the tissue carrier webs S and 6 before they reach -
the nip of rollers 3 and 4.
The wetted carrier layers 3, 4 then receive the
layer of particulate gel at the nip of the two rollers
3 and 4 and thereafter feed forward as a composite
2~ sandwich ply through ~ heating chamber 11 which removes
moisture from the tissue carriers and gel, round a
cooling roller 12 and thence to a storage reel 13.
The heating chamber 11 is an enclosure consisting
essentially of an open feedthrough system of rollers 14,
radiant heaters 15, and forced extraction exhaust duct 16.
The material on the storage reel 13 is slit on a
conventional slitting machine into a width to suit the
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tampon dimensions and the required number of layers of
sandwich stock material.
Referring now to Figure 2, this shows the first
part of the system for the production of tampons from
the gel sandwich stock material formed on ~he equipment
described with reference to, and as shown in Figure 1 r
In Figure 2 this sandwich stock material 18 may be
used in one, two, three or four layers which may be
formed using cutting, folding, and direction re-orientation -
systems as required. These methods are well known to
those skilled in the art and for clarity only the single
layer sandwich 17, and the cutting knife 20 are shown in
Figure 2.
The discrete pieces 21 of sandwich material thus
formed are fed by the conveyor 19 to the next stage.
At the next stage a web 22 of a non-woven outer
cover material i8 fed from a sspply ~eel 23 in the
longitudinal feeding direction followed by the sandwich
stock material 17.
The feed speed of the non-woven web 22 is just over
¦ twice the speed of feed tof the stock material 17. Thus,
the discrete pieces 21 are picked up by the web 22 with a
spacing between successive pieces which is slightly
greater than the length of each piece.
A polished shaped guide piece tnot shown) then forces
the web into a sleeve shape on a mandrel 25 with the two
edges of the web 22 overlapping. These webs are heat
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sealed or glued by a roller 24 as the web feeds onto
the mandrel 25. -
Referring now to Figure 3, the mandrel which is a
low surface friction bar having a hollow 26 at its
further end, carries a series of spaced ~ieces of
sandwich stock 21 surrounded by an overlying sleeve
shaped layer of non-woven material 22. The material is
carried along the mandrel by a pair of endless belt
conveyors 27 which each carry spaced rubber grippers 28
located to grip the web at the points where the pieees
of sandwich stock 21 locate.
The material is fed off the end of the mandrel to a
position where a pair of cutter rollers 29 bring knife
edges together to cut the end of the web 22. An air
blast jet 30 is then actuated, and this forces the free
end of the web back into the hollow 26 at the end of
the mandrel (see F~gure 4). The grippers 28 are
continuously feeding the material on, so that the folded
material passes the cutter rollers. Then, when the
position shown in Figure 3 is again reached, the so-formed
tampon (at the extreme right hand position of Figure 3)
is severed.
In an alternative form tnot illustrated) a suction
method i8 employed. In this case the mandrel is hollow
down its whole length (see dotted lines in Figure 4~ and
suction is produced down the hollow to introvert the web
material. In this case a rotary air valve is synchronised
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with the cutter rollers to open immediately after the
cutting of the web. This allows the suctionc-of~a
continuously running fan to be interconnected ~ia a
flexible tube to the hollow mandrel. At the open end
of thehhollow mandrel there is therefore imposed a
suction force on the web. The resultant low pressure
from suction causes the ambient air pressure to
introvert the web.
The so-formed tampon is then fed to further machinery
where the tampon is compressed to a tight cylindrical
form, a string is tied to the end, and is inserted in a
telescopic cardboard applicator.
These latter can all be standard operations, well
known in the art and in consequence have not been
described although it should be not~d that the tucks can
be formed by stationary fingers which cause the web to
tuck in as the sleeve leaves the mandrel. Alternatively
the tucks can be produced after the cutting knife, whilst
the tampon sleeve is gripped only along a narrow width
on the centre line of the machine. Rotating tucking
discs can introduce the tucks at this stage. A further
alternative is to produce the tucks by a combination of
both methods.
Reference is now made to F~gure 5 which diagrammatically
shows a tampon in accordance with the invention, having a
` withdrawal cord 31. In the tampon shown, the sandwich
; is folded into~two layers, and it will be seen that the
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absorbent gel material 32 is well protected, by virtue
of two layers of material, one of tissue 5 or 6 and one
of the non-woven outer 22. Moreover these two layers
of material act as both a capillary path, and a
temporary reservoir until the gel has absorbed the
extant liquid.
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