Note: Descriptions are shown in the official language in which they were submitted.
CA 02507914 2005-05-19
Title
FRANGIBLE PISTON PUMP
Scope of the Invention
[0001] This invention relates to piston pumps for fluid dispensers and more
particularly to a piston pump in which a piston is frangible so as to be
broken and render
the pump inoperative.
Background of the Invention
[0002] Fluid dispensers are known in which fluid in a reservoir container or
bottle is
to be dispensed from the bottle out of an outlet from the bottle via a pump
mechanism
secured in the outlet of the bottle. Such pump mechanisms are known in which a
piston
is coaxially slidable into a piston chamber forming member to dispense fluid
from the
bottle. Many known piston mechanisms provide an arrangement in which the
piston can
manually be removed from the piston chamber forming member and the bottle can
then
be refilled.
[0003] Unauthorized refilling of bottles can provide problems as to warranties
and
ensuring product quality and that product may be dispensed within a suitable
product life.
[0004] Known pump mechanisms include those disclosed in U.S. Patent No.
5,676,277 to Ophardt issued October 14, 1997 and U.S. Patent No. 6,601,736 to
Ophardt
issued August S, 2003, the disclosures of which are incorporated herein by
reference.
Summary of the Invention
[0005] To at least partially overcome these disadvantages of previously known
devices the present invention provides a piston pump with a reciprocally
movable piston
with an inner portion of the piston being engaged within a piston chamber
forming body
such that when forces are applied to the piston attempting to withdraw it from
the body
an inner portion of the piston breaks off from the remainder of the piston
rendering the
piston pump inoperable.
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[0006] An object of the present invention is to provide an improved piston
pump with
a frangible piston.
[0007] Another object is to provide a dispensing apparatus including a
container and
piston pump which is resistant to unauthorized refilling.
[0008] The present invention provides in the context of a dispensing apparatus
including a fluid containing container and a piston pump for dispensing fluid
from an
outlet of the container, a piston which is movable between retracted and
extended
positions to dispense fluids, which piston has a piston inner portion
connected to a piston
outer portion by a weaken strength, frangible intermediate portion which is
broken to
sever the piston inner portion from the piston outer portion on axially
directed forces
being applied to the piston second portion greater than the forces required
for normal
operation of the pump. In the event that the piston is attempted to be removed
from a
piston chamber forming member in which the piston is axially slidable, catch
element on
the piston inner portion engage catch elements on the piston chamber forming
member
such that axially outwardly applied force come to bear on the frangible
intermediate
portion breaking the same and severing the piston inner portion from the
piston outer
portion. The severed piston inner portion preferably remains in the piston
chamber
forming member preferably blocking fluid flow therethrough in one or both
directions,
preferably inwardly. Reciprocal movement of the piston forming element from
which the
piston inner portion has been detached is inoperative to pump fluid.
[0009] In one aspect the present invention provides a pump for dispensing
fluids
comprising: a piston-chamber forming member having a chamber about a chamber
axis,
the chamber having a chamber wall, an inner end, an open outer end, an outlet
and an
inlet, a piston forming element received in the piston-chamber forming member
axially
slidable inwardly and outwardly therein between an extended position and a
retracted
position in cyclical operation of the pump to draw fluid into the chamber via
the inlet and
dispense fluid via the outlet, the piston forming element having: an outer
portion
extending outwardly from the chamber through the open outer end, an inner
portion in
the chamber inwardly from the outer portion, an intermediate portion coupling
the outer
portion to the inner portion, and a piston catch member inwardly from the
intermediate
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portion, the intermediate portion being frangible and breaking to sever the
inner portion
from the outer portion when an axially outwardly directed breaking force is
applied to the
outer portion, the breaking force being greater than axially outwardly forces
required to
slide the piston forming element from the retracted position to the extended
position, a
chamber catch member carned by the a piston-chamber forming member engaging
the
piston catch member when the piston forming element is slid outwardly relative
the
piston-chamber forming member at least as far as the extended position and
preventing
outward movement of the piston catch member past the chamber catch member
under
axially outwardly directed forces applied to the outer portion which are equal
to or
greater than the breaking force, wherein when the inner portion is severed
from the outer
portion the pump is rendered inoperative and does not dispense fluid on
axially sliding of
the piston forming element inwardly and outwardly between the extended
position and
the retracted position.
Detailed Description of the Drawings
[0010] Further aspects and advantages of the present invention will become
apparent
from the following disclosure taken together with accompanying drawings in
which:
[0011] Figure 1 is a schematic cross-sectional side view through a dispenser
in
accordance with a first embodiment of this invention;
(0012] Figure 2 is an enlarged cross-sectional side view of the pump mechanism
shown in Figure 1 with the piston in a fully retracted position;
[0013] Figure 3 is a cross-sectional view the same as Figure 2 however with
the
piston in a fully extended position;
[0014] Figure 4 is a cross-sectional side view of the piston of Figure 2
showing the
piston as severed;
[0015] Figure 5 is a pictorial view of the pump assembly of Figure 2;
(0016] Figure 6 is a side perspective view of the piston of Figure 2;
[0017] Figure 7 is an enlarged pictorial view of the inner end of the piston
shown in
Figure 6;
[0018] Figure 8 is a cross-sectional side view along Section line 8-8' in
Figure 7;
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[0019] Figure 9 is an enlarged cross-sectional side view of a pump mechanism
similar to that shown in Figure 2 but of a second embodiment of the present
invention;
and
[0020] Figure 10 is a cross-sectional side view along Section 9-9' in Figure
9.
Detailed Description of the Drawings
[0021] Reference is made to Figure 1 which illustrates a dispenser generally
indicated
as 70 having a housing indicated as 78 to receive and support a removable
bottle
subassembly comprising a pump assembly 10 and a fluid container 26. Housing 78
is
shown with a back plate 80 for mounting the housing to a building wall 82. A
bottom
support plate 84 extends forwardly from the back plate to receive and support
the pump
assembly 10 and container 26 as with a support shelf 85 being received in an
annular
groove 21 about the body 18 of the pump assembly 12. A cover member 85 is
hinged to
an upper forward extension 87 of the back plate 80 so as to permit replacement
of the
subassembly of the pump assembly 10 and the bottle 26.
[0022] The housing 78 carries at a lower, forward portion thereof an actuating
lever
88 journalled for pivoting about a horizontal axis at 90. An upper end of the
lever 88
carnes a hook 94 to engage an engagement flange of a piston 16 of the pump
assembly
12 and couples the lever 88 to the piston 16, such that movement of the lower
handle end
96 of the lever from the position shown in solid lines to the position shown
in dashed
lines, in the direction indicated by arrow 98 slides the piston inwardly in a
return,
pumping stroke as indicated by arrow 100. On release of the lower handle end
96, spring
102 biases the upper portion of the lever 88 downwardly so that the lever 88
draws piston
16 outwardly to a fully withdrawn position as seen in dashed lines in Figure
1. Lever 88
and its inner hook 94 are adapted to permit manual coupling and uncoupling of
the hook
94 to the piston 16 as is necessary to remove and replace the bottle
subassembly
comprising the pump assembly 10 and the container 26.
[0023] In use of the dispenser 70, once exhausted, the empty container 26
together
with its attached pump assembly 10 are removed and a new bottle subassembly of
the
pump assembly 10 and the container 26 are inserted into the housing.
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[0024] The pump assembly 10 is best shown in Figure 2 as comprising a piston
chamber forming body 12 and a piston 16. The body 12 is generally cylindrical
in cross-
section and symmetrical about its central axis 13. The body 12 has an outer
cylindrical
hub portion 20 which provides an annular generally cylindrical plug portion 21
to which
an annular rim 27 of the container 26 is to be fixedly secured against removal
as for
example by sonic welding, gluing or by being received in a snap-fit.
[0025] The hub portion 20 also carries the radially outwardly directed annular
groove
22 to receive the support shelf 85.
[0026] The body 12 defines a stepped chamber therein as a first chamber 30
having a
cylindrical sidewall 32 and being open at an open axially inner end 34 and
open at an
axially outer end 36. The sidewall of the inner chamber 30 provides a
cylindrical interior
surface other than proximate the outer end 36 where an annular catch flange 38
extends
radially inwardly.
[0027] An outer chamber 40 is also provided having a sidewall 42, and an open
axially outer end 44 serving as an inlet to the outer chamber 40. The outer
end 36 of the
inner chamber 30 opens outwardly into an inner end and inlet to the outer
chamber 40.
[0028] The sidewall 42 of the outer chamber is cylindrical. The diameter of
the inner
chamber 30 is less than the diameter of the outer chamber 40.
(0029] The piston 16 is coaxially received within the body 12. The piston 16
is
generally cylindrical in cross-section about the axis 13. The piston 16 is
preferably a
unitary element formed entirely of plastic preferably by injection molding.
The piston 16
has a hollow stem 50 extending along the central longitudinal axis of the
piston 16.
[0030] A circular resilient flexing first disc 52 is located at the innermost
end of the
piston 16 and extends axially therefrom. The first disc 52 is sized to
circumferentially
abut the cylindrical sidewall 32 of the inner chamber 30 substantially
preventing fluid
flow axially outwardly therebetween. The first disc 52 has an elastically
deformably
edge portion near the sidewall 32 which is adapted to be deformed away from
the
sidewall 32 so as to permit fluid to flow axially outwardly past the disc 52.
[0031] A circular resilient second flexing disc 54 is located on the stem 50
axially
outwardly from the first flexing disc 52. The second disc is in the second
chamber 40
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and is sized to circumferentially abut the cylindrical sidewall 42 of the
outer chamber 40
so as to substantially prevent fluid flow inwardly therepast. The second disc
54 has an
elastically deformable edge portion which extends radially and axially
outwardly.
[0032) A third disc 56 is located on the stem 50 axially outwardly of the
second disc
54. The third disc 56 is also in the second chamber 40 and is sized to
circumferentially
abut the cylindrical sidewall 42 of the second chamber 40 substantially
prevent fluid flow
outwardly therepast.
[0033] The piston stem 50 has a hollow central passage 58 extending along the
axis
of the piston 60 from a closed inner end 59 to an open outlet 61 at the outer
end of the
piston 16. An inlet 62 is provided through the stem SO providing via a short
radial
passageway from between the second disc 54 and third disc 50, communication to
the
central passageway 58.
[0034) The pump mechanism 10 is operative to dispense fluid from the interior
of the
container 26 out the outlet 61 in a cycle of normal operation in which the
piston 16 is
moved relative to the body 12 from the retracted position shown in Figure 2 to
the
extended position shown in Figure 3 and to then return to the retracted
position shown in
Figure 2. In moving in an extension stroke from the retracted position of
Figure 2 to the
extended position of Figure 3, fluid from the container 26 is drawn through
the inner
chamber 30 into the outer chamber 40 by reason of the volume in the chambers
between
the first disc 52 and the second disc 54 increasing, creating a vacuum to draw
fluid from
the container 26 outwardly past the first disc 52. In moving from the extended
position
of Figure 3 to the retracted position of Figure 2, fluid between the first
disc 52 and second
disc 54 is pressurized and urged outwardly past the deflecting second disc 54
to between
the second disc 54 and the third disc 56 and hence via the outlet 62 into the
passageway
58 and out of the outlet 61.
[0035] Outward of the third disc 56, the stem 50 carnes a four axially
extending outer
webs 64 which are circumferentially spaced and serve to engage the sidewall 42
of the
outer chamber 40 and assist in maintaining the piston 16 axially centred in
the outer
chamber 40. Axially outwardly of the web 64, the stem carnes an engagement
flange 66
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adapted for engagement by the hook 94 of the lever 88 shown in Figure 1 to
move the
piston 16 between the extended and retracted positions.
[0036] Inwardly of the second disc 54, the stem 50 carnes four axially
extending
inner webs 68 which extend radially from the stem 50 to engage the radially
inner
periphery of the annular catch flange 38 and assist in maintaining the piston
16 axially
centred in the inner chamber 30. In the embodiment illustrated, both the outer
webs 64
and the inner webs 68 are provided as four webs, pairs of which are
diametrically
opposed.
[0037) The inner webs 68 each end at axially inward end 69 from which a strut
member 71 extends axially to connect each of the four inner webs 68 to a
corresponding
piston catch member 72 which extends from an inner portion of the stem 50
radially
outwardly past the webs 68 and into sliding engagement with the sidewall 32 of
the first
chamber 30. Each of the piston catch members 72 presents an axially outwardly
directed
piston catch shoulder 73. The annular catch flange 38 of the first chamber 30
presents an
axially inwardly directed chamber catch shoulder. On sliding of the piston 16
to the
extended position illustrated in Figure 3 the piston catch shoulder 73 and the
chamber
catch shoulder engage to prevent movement of the piston catch shoulder 73
outwardly
passed the chamber catch shoulder. The piston catch shoulder 73 has a radially
innermost edge which is radially inward of a radially outermost edge of piston
catch
shoulder.
[0038] With the piston 16 in the extended position as illustrated in Figure 3,
if axially
directed forces are applied to the piston, the engagement between the piston
catch
member 72 and the chamber catch flange 38 resists further outward movement of
the
piston 16 with the axially directed forces being transferred from the
engagement flange
66 through the piston 16 to the piston catch member 72 via the four strut
members 71.
[0039] With the piston member 16 formed as an integral member formed from
plastic
as by injection moulding, the strut members 71, when subjected to axially
outwardly
directed forces greater than a breaking force will break such that each of the
four inner
webs 68 will become severed from its corresponding piston catch member 72. In
this
regard, the strut members 71 form a frangible intermediate portion of the
piston which is
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intermediate an inner portion 100 including the piston catch member 72 and the
first disc
52 and an outer piston portion 102 including, amongst other things, the inner
webs 68,
second disc 54, third disc 56, outer webs 54 and engagement flange 66.
[0040] Reference is made to Figure 8 which illustrates a cross-sectional side
view
along section line 8-8' in Figure 7, showing the cross-section through each of
the four
strut members 71 as cross thatched circles since each of the strut-like
members are
conical. Figure 8 shows the cross-sectional area represented by the webs 68,
which is
many times greater than the sum of the cross-sectional areas of the strut
members 71.
[0041] In the preferred embodiment illustrated, the sum of the cross-sectional
areas of
the strut members 71 are substantially less than the sum of the cross-
sectional area
through any other portion of the stem 50 axially outwardly of the strut
members 71.
Accordingly, on the application of the axially outwardly directed forces to
the piston 16
as on the engagement flange 66 axially outwardly from the strut members 71,
such forces
are applied across the strut members 71. When the piston catch members 72 are
prevented from outward movement, applying to the engagement flange 66 a force
sufficient will break the frangible strut members 71 and result in severing of
the outer
portion 102 of the piston from its inner portion 100.
[0042] Reference is made to Figure 4 which illustrates a condition of the pump
assembly 10 when the outer portion 102 of the piston 16 has been severed from
the inner
portion 100. The inner portion 100 is shown as including the piston catch
member 72
and the first disc 52 which remain received within the inner chamber 30 and
effective
serve to restrict fluid flow inwardly therepast.
[0043] The outer portion 102 of the piston 16 is free to be removed outwardly
out the
open outer end 44 of the outer chamber 40. Reciprocal movement of the outer
portion
102 of the piston 16 within the body 12 will not result in pumping of fluid
from the
container 26.
[0044] In operation of the preferred embodiment, in the normal stroke of
operation,
the piston 16 may be moved between a retracted position and an extended
position. The
extended position need not be a position as illustrated in Figure 3 in which
the piston
catch member 72 engages the chamber catch flange 38. Preferably, in a full
stroke of the
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piston 16 as controlled by the lever 88, the piston 16 will reach an extended
position
which is axially inwardly from the fully extended position and thus ensuring
that in
normal operation of the piston pump, by movement of the lever 88, the piston
catch
member 72 will not come to engage the annular catch flange 38.
[0045] In normal operation of the pump with movement of the piston 16 between
a
retracted position and an extended position, axially forces are applied to the
outer portion
102 of the piston pump. In normal operation such forces include normal axially
outwardly directed forces to move the piston from a retracted to an extended
position in
normal pumping which are less than an axially outwardly directed breaking
force which,
when applied to the piston 16, will rupture the strut members 71. To state
this another
way, the breaking force which is applied to the frangible strut members 71 is
greater than
the axially outwardly directed forces required to slide the piston 16 from the
retracted to
the extended position and movement of the pump 16 to normally operate the pump
assembly 10.
[0046] The strut members 71 may have different forms. Preferably as shown, the
strut members 71 extend normal to the axis 13 and each strut member is of a
similar
cross-sectional area and shape.
[0047] In the preferred embodiment, for assembly of the pump assembly 10, the
piston catch members 72 are adapted to be moved inwardly into the inner
chamber 30
past the annular catch flange 38. In this regard, the annular catch flange 38
of the first
chamber 30 carnes an outwardly directed surface which is tapered to extend
axially
inwardly and radially inwardly so as to provide a bevelled cam surface adapted
to engage
an upper camming surface on the inner side of the piston catch members 72.
Engagement
of the cam surfaces with the camming surfaces assists in deflecting the piston
catch
members 72 inwardly and/or the annular catch flange 38 outwardly such that the
piston
catch members 72 may pass upwardly into the inner chamber 30 in assembly.
Similarly,
the first disc 52 on the piston inner portion 100 are adapted to pass inwardly
past the
chamber catch flange 38.
[0048] Reference is made to Figure 9 which illustrates a second embodiment of
a
pump mechanism in accordance with the present invention. In Figure 10, similar
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reference numerals are used to the reference numerals in the first embodiment
to illustrate
similar elements.
[0049] In Figure 9 the body 12 is shown to be modified to eliminate the second
chamber 30 and to provide an equivalent radially inwardly extending annular
flange 38
on the wall 42 of the chamber 40. The piston 16, however, has been modified to
eliminate the inner disc 52 of the first embodiment and, as well, portions of
the stem SO
inward of the piston catch member 72. In replacement of the inner disc 52, a
one-way
valve 104 is provided across the inner end of the inner chamber 30. The piston
catch
members 72 are formed as a top portion of the webs 68 without frangible
members
therebetween. Rather, as best seen in cross-section in Figure 10, the sidewall
of the stem
SO intermediate the second disc 54 and the third disc 56 has been reduced so
as to provide
enlarged openings 62 bridged by a plurality of strut members 63 of reduced
cross-section
and therefore reduced strength such that they are frangible. In the embodiment
of Figure
9, the inner portion of the pump which is to remain after severing within the
body 12
comprises that portion inward from the frangible strut members 63 and
therefore includes
the second disc 54 and the inner web 68 carrying the piston catch member 72.
The outer
portion which becomes severed includes the third disc 56, the web 64 and the
engagement flange 66.
[0050] Figure 1 illustrates the first embodiment of the invention used with a
collapsible container 26, however, the first embodiment may be used with rigid
containers as with various venting mechanisms whether through the container
wall or
through the pump mechanism. The frangible piston of the preferred embodiments
may
be used in a wide range of pumps having chambers in which the piston is
slidable.
[0051] Many modifications and variations of the invention will now occur to
persons
skilled in the art. For a definition of the invention reference is made to the
following
claims.
