Note: Descriptions are shown in the official language in which they were submitted.
:IL045597
FIELD O~_T~E INVENTION
This invention is concerned with improvements in or
relating to dispensers for flowable materials~
BAC~GROUND AND PRIOR ART
- Dispensing devices for pastey materials are kno~Jn, in
which the pastey material is contained in a resilient bag
located within a housing, one end of the bag communicating with '~
an outlet in the housing and the other end of the bag being
connected to a rotatable member so that it can be twisted to
extrude the material from the outlet. Since the bag tries to
shorten on twis-ting, various compensa-ting de~ices have been
proposed to allow the twisted end of -the bag to move axially -~
while transmitting the rotation of the rotatable member.
However, it is important that the twisting should start from
the end remote from the outlet and progress steadily along the
bag~ so that substantially no material is retained in the
twisted portion. For ext~uding very viscous substances such as
mastic, or to obtain a liquid spray, high pressures have -to be
developed, and it has been found to be particularly important
to control the twisting of the bag~ especially in the early
stages, if efficient~ expulsion of material and sufficiently
high pressures are to be obtained.
~rench Specification 1161905 shows a freely hinged
buckle connecti~g the end of the bag to the rotatable end member,
so that the buckle, which is initially flat against the end
member, is li~ted by the bag as it twists. HoweYer~ in this
arrangement the tw~sting~end o~ the bag is largely unrestrained, ~ -
particularly in the inltial stages9 so that the twisting will
~ tend to become irregular and off-centreO
~ 30 U~S.~Specification 1491860 shows alte~lative! ~ ~
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compensatin~ devices. One uses a helical spring connecting
the end of the bag with the end of the housing. The other has
the tail of the bag held in a small aperture in a resi~ient
disc at the end of the housing so that it can pull through the
aperture as it is twisted. However9 the use of a resiliently
extendable compensating member such as a spring has been found
to be unsatisfactory, since the spring, if sufficiently
extendable, does not maintain sufficient axial tension on the
bag to adequately control ~ts twisting, and moreover tend.s to
absorb too much energy during rotation and prevents the
development of high pressures. m e resilient disc arrangement ~ -
for its part does not hold the end of the bag sufficiently `
firmly to transmit the high rotational forces and maintain
sufficient axial tension on the bag to achieve high pressures
w~thin the bag.
U.S. Specification 2203313 describes a compensating
de~ice oomprising a springy plate to the centre of which the
tail of the resilient bag is attached. The plate is lntPrnally ~ -
slotted so that the centre portion can be resiliently drawn
upwards by the bag as it shortens during twisting. This suffers
from the same disadvantage as the spring as described above, and
further cannot transmit high torque to produce high pressure in
the bag without risk of distortion or fracture of the plate at ~;
one of its many wsak points.
SUM~A~Y OF THE INVENTION
e present invention rests in the surprising discove~y ~
~that~to obtain high pressures in the bag any undue resilience ~ ~ -
in the system should be avoided. More~specifically, although
lt might be expected that a~rubber or other resilient bag would~
30 ~ perform best in llowing pr~ssure to be built up and in storing
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the twist energy, in fact it has been found that a bag of non-
stretchable material produces much better results. Moreover,
it is important that the compensating device should not only
be able to transmit high torque, but also it should fulfil two ~ ~
~-~ further requirement~ Firstly, it should have sufficient ~ -;
resistance to axial extension to keep the t~isted tail of the
- bag siraight and ensure that the twisting progresses steadily
and efficiently from that end of the bag. Secondly, when it
does allow the tail of the bag to advance axially, it should ~ ~
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do so in an essentially non-resilient manner, so as not to
absorb the applied torque, nor apply increasing axial tension -~
on the bag as it rises further up the housing, as would happen
with a spring device.
~or the bag material, polyester ~ilm has been found -to ~r
prov~dc +ho d2sir~d ~.~ h tcns~lr n^n-stret~h qualities, although
other materials are no doubt suitable and still others will be
developed in future. ~;
For the compensating device, two particular forms have
been found suitable, both of them being modifications o~ the
arrangements shown in U.S. Specification 149~860, although they }
were not in fact devoloped from them. In one form, the end of
the bag is formed into a flat tail which is firmly gripped in a
~- rlgid slot, so that although it can be pulled through the slot
by-the application of suf~icient~force, the rigid slot does not
yield, as~would a slotted rubber disc9 and thus the grip is ~
maintained e~ually effecti~ely under high toFque, and the high ~-
torque can be effectively applied. In the other form the tail
o~ the bag is~secured through a spiral member which c~an expand
axlally ln an essentlally non-res1lient fashion/ but which -~
~0 exerts considerable resistanCe to such expansion. This
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resistance can be due to the thickness of the material of the
spiral, e.g. a thick steel wire, or it may be due to the shear
resis~ance of a plate having a spiral~line of weakening from
which the spiral is gradually torn. The spiral device can
transmit high torque in the direction of the spiral without
great risk of undue distortion or fracture.
~ A particular advantage of the present invention :is
thai it enables sufficient presæure to be built up in the bag ~
to provide an effectlve fine spray of a liquid, comparab:Le ,~ -
with an aerosol s~ray. A preferred embodiment of the invention
therefore employs a manually operated valve in the outlet
passage and a spray nozzle at the end of the passage.
BRIEF DESCRIPTION OF THE DRAWINGS
ND DESCRIPTION OF SPECIFIC EMBODIMENTS ~
In order that the invention may be more clearly ` ~ ,
understood, various embodlments will now be described with
reference to the accompanying drawings, wherein:
Fig. 1 shows a cross-sectional view of a first
embodiment~ of dispenser; ;
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` - Figs 2 and 3 show perspective views of two different
forms of compensating device for the dispenser;
Fig. 4 sho~s a cross-seotional view of a second
embodiment of dispenser;
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Fig. 5 shows a cross-sectional view of a third
embodiment of dispenser;
Fig. 6 shows a cross-sectional view of a four~
embodiment of dispenser;
; Fig. 7 shows an exploded perspective view of the bottom
portion of the embodiment of Fig. 6;
Fig. 8 shows a cross-sectional view of a fi~th
embodiment of dispenser; and
Fig. 9 shows an exploded perspective view of an
alternative bottom arrangement of the dispenser of Figs. 6 and ,
8.
Referring to the drawings, and ~irstly to Fig. 1; the
dispenser comprises a strong flex7 bl~ ~ag-' Ir~ ocntain~r 1û
carrying a liquid, for example a water-based insecticide,
which is to be dispensed as a spray. The bag is suitably made
polypropylene or (Trade Mark)
from/"~elinex"/polyethylene terephthalate sheet material. m e
container is l~cated within a rigid tubular housing 2, suitably ~-
of plastics material. A dispensing component 11 o~ moulded
plastics material is provided with an annular groove 12 which
receives the rim of~the housing at one end thereof, the mouth
of the bag 10 being turned outwardly over the rim of the
housing and trapped between the housing and the dispensing
component. The dispensing component is provided with an outlet ~ ;
passage 14 for the liquid, which has a conical inner end 16
opening into the housing. A valve 18 in the outlet passage 14 ~ ~ -
is controlled by a spring-loaded plunger 20. A nozzle ~elemen-t
2~ is fitted at the outer end of the passage 14.
The lower end of the housing 2 carries a rotatable end
cap 32 which is held captive by a flange 30 of the end lt:ap
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entering a groove 29 of the housing. Ratchet teeth 31 are ~ ~
provided on the outer surface of the lower end portion of the ~ - housing, and complementary ratchet teeth ~3 are provided on
the inner surface of the end cap; The ratchet teeth
resilientl~ interengage, and are preferably sa~1-toothed in
cross-section so that they allow the cap to be rotated in one
direction but resist rotation in the opposite direction. The
end cap is connected with the lower end of the bag 10 by means
of a compensating element 40 which is hooked onto a lug 38 of
~0 the en~ cap and onto a ring 42 attached to the lower end of ~
the bag by means of a loop ~ormed in the lower end o~ the bag
~0 which ~s gripped and sealed by a crimping clip 44.
In operation, the end cap is rotated to twist the lower
end portion/of the bag and thereby compress the liquid which is
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released as a spray from the nozzle 21 when the Plunger 2~ i5
depressed.
m e compensating device 40 is of the form shown ln Fig. -
2, and comprises a length of wire~hooked at its ends 23,25 and
twisted into the form of a coil 27. The material of the wire
is permanently deformable so that the hooked ends can be drawn
apart as continued use of the dispensing device causes the lower
end of the bag to rise to within the housing. Ho~ever, the wi~e
material must provide resistance to the axial movement of the
bag and be capable of transmitting the rotation of the end cap/ ~ ~ -
lower end of the containerO 12 or 14~ swg. mild steel wire is
generally adequate for this purpose, but thinner wire, such as
1~ s~g. may be appropriate for smalIer packsO
; Fig. 3 shows an alternativé form of compensating ,
device/,wherein the end cap 32 ha-s an end wall, suitably of
~30 plastics or metal, which~is providéd with a centr~lly
dlsposed loop~35 hrough ~h~ch the lower end portion ~ t
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~ 1045597
of the bag is passed and secured. The er~ wall is scored at ~;
39 to define a spirally shaped tear line. As the end cap is
rotated, the rotation is transmitted to the end of the bag~
and axial tension is applied by the bag to the end cap, which
offers a degree of resistance to the tearing of the score line, ~ -
but under sufficient force the end cap gradually tears along the 't
score line to provide a tear out strip in the form of a coil.
This is substantially equivalent to the device shown in Fig. 2.
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HoweYer, the coil 27 thus produced will take the form of a flat
10 ribbon of metal or plastics material which has a greater ~ 3
ability to transmit rotational force but has minimum resilience
in the axial direction.
Re~erring to Fig. 4; the dispensing device comprises
~ a bag-like container 10, for example containing a pastey
- substance such as pre-mixed mustard. It is located within a
rigid tubular housing 2 of plastics m~terial, which has a
substantially cylindrical tubular portion 1~ which merges into -
a narrower neck portion 15 providing an outlet to the housing.
The neck portion has an out~ardly directed annular rib 17 at
Z0 its extremity. The upper mouth of the bag 10 is turned over
the flange ~7 and held in place by engagement in a co-operating
annular rebate 19 of a dispensing component 11. An outlet
passage 14 for the contents is provided in the nozzle
componentO When not~in use,~the outIet orifice can be closed
by an appropriately shaped plug 27. ~
The lower end of the housing i9 provided with a
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rotatable cap 32, which is essentially similar to that of Fig.
1, except that instead of the two sets of co-operating ratchet ~`
~teeth, teeth 34 are formed on the inner cylindrical surface of
~30 the end cap to operate in the manner of a ratchet with pips 36
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spaced at regular intervals around the outer surface of the
housing. The lower end of the bag 10 is connected to the end
cap by means of a compensating member 40 which is essentially
similar to that shown in Fig. 10 '-.' l~ `
In this embodiment, the end cap can be rotated in
either direction, the teeth and pips merely providing a
resistance to rotation. After the required amount of material ~ r
has been expelled, the end cap can be rotated a little in the
reverse direction before replacing the plug so as to relieve
any undue pressure in the container and prevent -the plug from ~
being forced off. ; ¦
~ The embodiment shown in Fig~ 5 consists essentially of ; f
a combination o~ two of the dispensers of Fig. 4. A single `
housing 2 has two separate dispensing components 11 ~upplied
by separate bag-like containers 10 within the housing. The
lower ends of the two bags are closed and jointly connected
to a single compensating device 40 which links them to a sLngle
rotatable end cap 32. The two bags contain separate materials
which it is desired to dispense simultaneously and in equal
~20 proportions. l'ypically, this may be a two-part adhesive
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composition. me dispensing components are arranged so that
tbe two materials are dLspensed~to~ards each other. In this :
embodiment, the neck of each bag 10 is shown as being sealed
~to the inside surface of the neck portion 15 of the housing, ~`
instead o~ being turned over~the flange 170 . .
~ m e embodiment~sho~n in FigsO 6 and 7 is essentIally~ ;
; similar to that of ~igo 4~, except for the compensating
arrangemen~ at ~he~lower~end of the contalner bag. In this ~ - ;
~ : case, the lower end~portion o ~the bag 10 is twisted in the~
;;~30 ~region 41, and its extremity is formed in the shape of a flat
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portion
tai~ 43 which can be sealed by a crimped metal tie 45 which
also provides an end stop. The tail portion extends through ~`
a trangular hole 47 in a transverse w~ll 49 of the end cap, ~ -
and is trapped therein by a wedge 51. The hole 47 is provided
with a re-entrant groove 53 intended to receive the tail
portion 43, and the wedge 51 is provided wi-th retaining
shoulders 55. me hole 47 and the wedge 51 are shaped so as to
interfit in such a way that the tail po~tion 43 is frictionally
gripped between the wedge 51 and the groove 5~ to a desired
extentc The end cap extends be~ow ~he transverse wall 49~ and
is provided with a groove 57 to receive an end plate 59 which
portion
retains the ~ail/43 and hides it from view. Initially, with `~
the bag filled with the material to be dispensed, as much as ~L
possible of the tail portion 43 is contained in the space
between the trans~erse wall 49 and the plate 59. Rotation of ~ ~
the end cap causes the tail of the bag to be twisted, since ~ ;
the tail is prevented by the wedge 51 from rotating rela-tive -
to the end cap. The continued twisting of the lower end of the
container thereby causes the contents to be expelled when the
plug 27 is removed. After the requir~damount has been
dispensed the end cap will be rotated a little in the reverse
direction and the plug replaced. The frictional grip exerted
on the tail portion 43 by the wedge is arranged to be such as
- to still permit the tail portion to be pulled by the bag
through the wall 49, thus compensating for the shortening of -
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the bag as it is twisted.
Fig. 8 shows a modification to the embodiment o:E Fig. 6
similar to the embodiment of Fig. 5, in which there are t~lo
containers in the-housing, each supp~ying separate material to
a respective d~pensing component. The lower ends of the t~lo
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containers are twisted together and taken as a single tail
through the transverse wall 35.
Fig. 9 shows a modification to the end cap arrangement,
suitable for the embodiments of Figso 6 to 8~ In this i-
modificat~on, the end cap 32 is moulded from plastics ma-terial, -~
and is mounted to the housing 2 in the manner already described ,-~
It is provided with diametrically opposed perforated lugs 50 ~`
which receive end portions of a split pin 520 The tail portion
43 of the container is threaded through the split pin during -
assembly, and is frictionally gripped between the legs 54 of
the split pin. An end cover 56 is arranged to fit over the
end cap 32 to hide the -tail portion from view. As in the
previous embodiment, when the end cap is rotated so as to twist
the lower end portion of -the container, axial -tension is built
up~ which pulls the tail portion between the leg portions 54 *
of the split pin, which exert a ~rictional grip transmitting
the rotational movement to the container and opposing to ~ -
limited extent the movement o~ the tail portion between them.
As an al~ernative to the arrangements illustrated
above? the rotatable member may be provided at the dispensing `
end, the dispensing outlet being Frovided in the rotatable
member which is connected to the flexible container, the other
end of the container being connected through a compensating
element: to the other end of the housing. Howe~er, if the
pressure in the container causes it to bear upon the sides o~ -
the houslng, then the ro-tatable member should be at the end ~
of the housing remote from the outlet. . .
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~ The valved outlet arrangement o~ Fig. ~ can be app:lied ~
to other embodiments, even to dispensing pastey or viscous ~ ~;
materials, althougb n spray nozzle would not be used. In the
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tw~ bag embodiments valves in the two outlets could be operated ,~ -
simultaneously by a single plunger. One bag could contain a `~
liquid and the other a gas or highly volat:ile liquid, so that .
the two jets impinge on each other, the gas or vaporised
liquid Jet servlng to atomise the other liquid jet.
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