Note: Descriptions are shown in the official language in which they were submitted.
WO 96128257 PCTIIB96I00391
1
A PUMP MADE OF PLASTIC FOR DISPENSING PRODUCTS FROM
CONTAINERS
The invention concerns an all plastic pump particularly suitable
for
dispensing liquid or thick substances from containers.
s As it is known, dispensing pumps are widely used for dosing
and dispensing
liquid or creamy substances, such as soaps, cosmetic creams,
detergents
and similar. Said pumps are applied to the container which
holds said
substances.
The majority of the pumps used at present are made of both
plastic
to materials and metal, the latter being mostly used for the
return spring of the
piston which forms the pump.
The presence of such metal materials entails some problems
for recycling.
In fact, should the pump be completely made of plastic materials,
even
differing from each other but being mutually compatible,
it is possible to
is entirely recover the material the pump is made of, by shredding
the pump
directly. On the other hand, the presence of materials which
are
heterogeneous in relation to each other and, in particular,
the presence of
metal materials, prevents such a direct shredding and requires,
for an
eventual recycling of the plastic material, a previous separation
of the metal
2o parts. The difficulty and the costs related to such a sorting
operation imply
that the dispensing pumps, once they are no longer useful,
are eliminated
as a waste, with the inconvenience of wasting plastic material
which
could be recovered and of increasing the amount of non-degradable
materials present among the waste.
2s Pumps are also known which, rather than using a spring made
of metal
material, use a bellows, as an elastic element made of plastic
material
obtained by a blow moulding process.
Said bellows element consists of a plurality of essentially
toroidal
elements, placed one on the other, so that the profile of
the bellows, in a
3o cross-section, presents itself as a series of expansions
and contractions
o arranged on horizontal planes and essentially parallel in
relation to each
other.
Said type of profile can only be realized by blow moulding,
because it is
impossible to remove the snapping tool from the bellows after
the moulding,
ss and, therefore, its realization with the injection moulding
process is not
WO 96128257 ~ ~ ~ ~ ' ' ~. PCT/1896/00391
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possible. The possibility for the bellows to be realized by injection moulding
process rather than by blow moulding, would yield a number of
advantages, one of which is the reduction of the production costs, since
injection moulding is quicker than blow moulding.
s Apart for this fact, the moulding of the bellows by injection would permit
to
obtain a thicker profile in the bending points which undergo a greater stress
and, therefore, it would permit to realize a bellows having a higher
mechanical
resistance.
The realization of a bellows made of plastic material is known from the
to Belgian patent 718118. Said patent describes a bellows used in the field of
distribution valves for the protection of the sliding elements of the valves
themselves. The bellows realized according to the dictates of the
mentioned patent presents its lateral surface in the shape of a spiral, so as
to obtain the bellows by injection moulding since the spiral profile permits
is the removal of the snapping tool.
The bellows of this type present one profile of the spiral in their
longitudinal
section, which is not essentially symmetrical in relation to the plane of
inclination of the spiral itself, so that they have a limited resistance when
they
undergo a pressing force because of the action of an axial stress which turns
2o into a smaller build-up of elastic power and, therefore, into a weaker
elastic
return when they are released.
It easy to understand that such a fact consitutes a negative factor for the
use of said bellows in the range of the pumps for dosing elements, wherein
it is necessary to have forces presenting a rather consistent elastic return,
as since the piston of the pump, once it has gone back to its resting position
after the dispensing action has been completed, must suck back the liquid
in order to prearrange the pump for the next dispensing operation.
The present invention proposes to overcome such limitations.
In particular, one of the purposes of the invention is to realize a pump made
so of plastic for dispensing liquid or creamy substances from containers,
wherein the elastic element, which ensures the return of the piston into its ,
resting position, is an elastic bellows presenting a higher elastic
coefficient
against the axial pressure, as compared to elastic bellows belonging to the
known technique and equivalent with it.
3s Another purpose is for the elastic bellows which realizes said pump
CA 02189997 1999-06-03
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to be complete with a higher elastic return as compared with equivalent
bellows belonging to
the known technique.
Further purpose of the invention is to realize the elastic return of the
bellow without
using materials different from those ones used for making the bellow.
In accordance with an embodiment of the present invention there is provided a
pump
for dispensing liquids adapted to be connected to a container for such
liquids, comprising: a
cylindrical chamber having a feed hole in flow communication with the
container when
connected thereto for receiving the liquid to be dispensed through the feed
hole; at least one
piston axially slidable within the cylindrical chamber between dispensing and
rest positions and
including a tubular chamber therein; valve means located within the
cylindrical chamber and
movable with respect to the piston between open and closed positions for
allowing dispensing
of liquids as the piston moves from the rest position to the dispensing
position; at least one
elastic bellows coupled to the piston and having walls in the shape of a
spiral having turns and
corresponding contraction areas for returning, by elastic recovery, the piston
to the rest
position once dispensing has occurred, wherein the elastic bellows includes an
integral spring
arranged in correspondence with the contraction areas of the spiral the turns
having a thickness
for producing a stiffening rib in an external surface of the spiral, the walls
of the spiral forming
a surface of the bellows having an outwardly convex profile.
In accordance with another embodiment of the present invention there is
provided a
dosing pump for dispensing liquid adapted to be connected to a container for
such liquid,
comprising: a dispensing element; a cylindrical chamber in flow communication
with the
dispensing element and having an inlet for receiving the liquid to be
dispensed from the
container when connected thereto; a piston slidably mounted within the
cylindrical chamber
having a stroke for motion between a rest position and a dispensing position
at corresponding
opposite rest and dispensing ends of the stroke; valve means coaxially located
with respect to
the cylindrical chamber, and movable with respect to the piston between open
and closed
positions, and including a first valve element in communication with the inlet
operative to close
when the piston is urged in a direction towards the dispensing position to
block liquid flow into
said cylindrical chamber, and to open when piston is urged in a direction
towards the rest
position for allowing liquid flow through the inlet and into the chamber, and
a second valve
CA 02189997 1999-06-03
-3a-
element located between the cylindrical chamber and the dispensing element and
operative
between open and closed positions for allowing liquid flow from the
cylindrical chamber to the
dispensing element when the piston is urged in the direction of the dispensing
position, and
operative to block liquid flow to the dispensing element when the piston is
released; an elastic
element for urging the piston to its rest position from the dispensing
position, wherein the
elastic element includes a plastic bellows formed by injection molding and
having a sidewall
in the form of a spiral shaped side surface, the sidewall of the spiral formed
with contracted
areas including an integral spring portion and an outwardly convex curved
profile extending
from the contracted areas.
According to one preferred embodiment, the spiral which forms the lateral
surface of
the bellows presents, in its longitudinal section, the walls having a
symmetrical profile in
relation to the axis of inclination of the spiral itself.
According to one embodiment, the bellows presents a cylindrical profile.
According to another embodiment, the bellows presents a profile in the shape
of a
truncated-cone.
Advantageously, the presence of the spring realized in a single piece with the
bellows,
yields a higher elasticity to the bellows itself and also gives it a greater
mechanical resistance.
Moreover, with advantage, the manufacturing of the spiral which forms the
lateral
surface of the bellows, which is symmetrical in relation to the axis of
inclination of the spiral
itself, permits to obtain a considerable elastic recovery of the bellows
whenever the pump is
released after the dosing.
With as much advantage, the spiral profile allows the realization of the
bellows
W 0 96128257 ~ PC'TIIB96100391
by injection moulding and permits to increase the thickness of the spiral in
correspondence with the bending areas where there is a greater stress.
Further scope of applicability of the present invention will become apparent
from the detailed description given hereinafter.
s However, it should be understood that the detailed description and specific
example, while indicating preferred embodiments of the invention, are
given by way of illustration only, since various changes and modifications
within the spirit and scope of the invention will become apparent to those
skilled in the art from this detailed description and from the drawings,
to wherein:
- Fig. 1 shows in a perspective view the pump according to the invention;
- Fig. 2 shows a longitudinal section of the pump according to the invention;
- Fig. 3 shows the suction pump of Fig. 2 during the dispensing phase;
- Fig. 4 shows in a cross-section the bellows of the pump according to
is the invention, presenting a cone-shaped profile;
- Fig. 5 shows a no-cutaway lateral view of the bellows of Fig. 4;
- Fig. 6 shows in a cross-section a different embodiment of the bellows
belonging to the pump according to the invention and realized with a
cylindrical profile;
zo - Fig. 7 shows a no-cutaway lateral view of the bellows of Fig. 6;
- Fig. 8 shows in a cross-section the enlarged profile of the spiral which
forms the lateral surface of the bellows belonging to the pump according to
the invention.
The pump according to the invention is represented in Fig. 1, wherein is
25 indicated as a whole with 1, and it can be observed that it comprises a
cylindrical collar 11, to the lower part of which a cylindrical chamber 13 is
connected, while an elastic bellows 40 is attached to its upper part. The
cylindrical chamber 13 is inserted into the neck of a container, not
represented in the drawing, which contains the product to be dispensed and
so the cylindrical collar 11 is tightened on the neck of the container itself.
A
dispensing element 10, provided with a dispensing inner channel 21, is
connected to the upper part of the elastic bellows 40, as can also be observed
in Fig. 2, and permits the dispensing of the product held in the container.
In Fig. 2 it can be observed that the dispensing element 10 is connected to
3s the tubular body 121 of a first piston 12 which slides inside said
cylindrical
~R'O 96128257 ~ 18 9 9 9 "~. PCT/IB96/00391
chamber 13 communicating with the container to which the
pump is
connected through a feeding hole 14 drilled at the bottom
130 of said
a cylindrical chamber 13.
Inside said tubular body 121 a tubular chamber 160 is defined.
a s Stem 16 of a second piston 120 slides within said tubular
chamber, said
stem 16 being provided with first valvular elements consisting
of a ball 22
suited to intercept duct 122 which sets into communication
said tubular
chamber 160 with said cylindrical chamber 13 and with second
valvular
elements consisting of a bevel 18 realized in the terminal
part of said second
to piston 120.
Again in Fig. 2 it can be observed that on the opposite side
of said duct 122
realized in said tubular body 121, there are third valvular
means consisting
of a ball 20 which intercepts the communication of said tubular
chamber
160 with the dispensing channel 21 obtained in the dispensing
element 10.
is Finally, it can be observed that said dispensing element
is mechanically
connected to said collar 11 by means of the interposition
of said elastic
bellows 40 which presents a first extremity 41 attached to
said dispensing
element 10 and a second extremity 42, opposite to the previous
one,
connected to said collar 11. Said bellows permits the mutual
elastic
2o movement of said dispensing element 10 and of said collar
11.
When the dispensing element 10 is pressed downward, it also
drags
downward the tubular body 121 to which it is connected, together
with the
first piston 12 which slides inside the cylindrical chamber
13. When said
first piston 12 descends, it pushes downward said second
piston 120, so
2s that said second valvular elements 18 intercept the feeding
hole 14.
When the dispensing element 10 is released, the elastic recovery
of bellows
40 makes the first piston 12 slide upwards again, thus creating
inside the
cylindrical chamber 13 a depression and, therefore, a lifting
of the second
piston 120 because of the pressure of the liquid coming up
from the
so container following direction 140 and which, through the
feeding hole 14
and the holes 15 drilled in the second piston 120, fills
the cylindrical chamber
13.
At this point, by pressing downward again the dispensing
element, the first
piston 12 descends together with the second piston 120, whose
second
ss valvular elements 18 intercept again the feeding hole 14.
The descent of the
R'O 96128257 , PCTI1896/00391
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first piston 12 compresses the liquid present in the chamber 13 which, as can
be observed in Fig. 3, flows following direction 131 from the cylindrical
chamber 13 into the tubular chamber 160 through duct 122, which is no
longer obstructed by ball 22. The pression of the liquid inside said tubular
s chamber 160 lifts said first valvular means 20 and enters into the
dispensing
channel 21 from which it pours out.
Once the dispensing has been completed, the released of the dispensing
element 10 permits the dispensing element 10 itself to slide back up into its
resting position because of the action of the elastic recovery of bellows 40,
to thereby causing again the refill of the cylindrical chamber 13 with the
liquid
coming from the container.
The pump 1 is thus ready to perform a new dispensing action as soon as
the dispensing element 10 is pressed downwards again.
It is important to observe that the elastic bellows 40 described and
is represented in the Figures 1, 2 and 3, is also represented in the Figures 4
and 5. It presents a tapered profile and its lateral surface, indicated as a
whole with 50, has the shape of a spiral. More specifically, said spiral
shape permits the realization of bellows 40 through injection moulding,
since the spiral shape allows by rotation the extraction of the snapping tool
20 once the bellows has been moulded.
As can be observed in the detail represented in Fig. 8, the elastic bellows
40 incorporates spring 63 which is obtained in a single piece together with
the bellows and its turns are located in correspondence with the contraction
areas of the spiral 80 which forms the lateral surtace 50 of the bellows.
as In particular, the spiral 80 presents, in its longitudinal section, an
essentially symmetrical profile in relation to its axis 70 which is slanted in
relation to the longitudinal axis 400 of bellows 40. The presence of such a
spring 63, together with the essentially symmetrical profile of each spiral
80,
is such as to allow the greatest build-up of elastic power during the
so pressing action. Said elastic power is released when the bellows
elastically
return into its resting position, once the axial force which has caused the
pressing stops.
During the return of the dispensing element 10 into its resting position, this
considerable amount of built-up elastic power permits a great suction of
ss liquid which is transferred from the container into the cylindrical chamber
13
~18999'~
'WO 96/28257 PCT/1896100391
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by means of the action of the first piston 12.
The possibility for the bellows to build-up and then release another
amount of elastic power is further increased since, as can be observed in
Fig. 8, the walls 60 of spiral 80 also present curved profiles 62 having an
s outward convexity, which make each spiral essentially acquire the shape of
Belleville washers thus permitting a good axial force after the pressing
action.
Therefore, with such a configuration of the elastic bellows 40, it is possible
to
obtain elastic returns having values which can be compared with those
to obtained by using metal springs, with the advantage of achieving, at the
same time, the possibility of a complete and immediate recovery and
recycling of the material which composes the pump.
In a different embodiment, as can be observed in the Figs. 6 and 7, the
bellows according to the invention, indicated as a whole with 500, can also
is be obtained with a cylindrical profile, yet maintaining the spiral 510
which
forms its lateral surtace 600, the symmetrical profile in relation to the axis
of
inclination 700 of the spiral and the same structure which incorporates the
spring.
A different embodiment of the pump according to the invention is represented
2o in the Figs. 9 and 10 wherein it can be observed that said pump, indicated
as
a whole with 300, foresees a different embodiment of the pistons with which
it is complete. In fact, it can be observed that, when the dispensing element
100 is pressed downwards, it also drags a first piston 320 connected with it,
which presents internally a cylindrical chamber 321 and slides inside a
zs cylindrical chamber 330 by means of the interposition of a second piston
360. Said first piston 320, during its downstroke, also drags the second
piston 360 by means of the projections 421, so as to obstruct passage 240
by means of the valvular element consisting of ball 180.
When the dispensing element 100 is released, as a consequence of the
3o elastic return of bellows 800, the first piston 320 and the second piston
360
also slide upwards. This creates a depression inside the cylindrical chamber
330. Said depression generates a suction of liquid from the container below
which flows through passage 240 no longer obstructed by the valvular
element 180 and which refills the cylindrical chamber 330.
3s By pressing down again dispenser 100 the liquid contained in the
cylindrical
R'O 96128257 PCTlIB96/00391
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chamber 330 is compressed and enters following direction 331 into the
first piston 320 through opening 322 obtained in the first piston 320 which
acts as a valvutar element by co-operating with said second piston 360. The
liquid then flows outwards through dispenser 100.
s In this different embodiment, too, bellows 800 presents its lateral surface
in the shape of a spiral so that it can be manufactured by injection
moulding. Moreover, each of the folds which form the lateral surface of said
bellows presents in a longitudinal cross-section a symmetrical profile in
relation to the axis of inclination of the fold itself, so as to create a
strong
io elastic return and, as a consequence, a great depression within chamber
330 when bellows 400 goes back to its resting position.
On the basis of what has been described, it is easy to understand that the
pump according to the invention together with the described elastic bellows,
reaches all the proposed purposes and also permits to obtain all the
is mentioned advantages.
It is obvious that the pump according to the invention can also be
manufactured with different shapes and dimensions concerning, for
instance, the dispensing element or the collar for its applicatiori on the
container. The latter can also acquire any shape or dimension and can be
2o used for more or less thick liquids.
All mentioned variations and others are to be considered as belonging to
the scope of the present invention.
3s
