Information
-
Patent Grant
-
6200055
-
Patent Number
6,200,055
-
Date Filed
Friday, June 18, 199925 years ago
-
Date Issued
Tuesday, March 13, 200124 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Plevy; Arthur L.
- Buchanan Ingersoll PC
-
CPC
-
US Classifications
Field of Search
US
- 401 263
- 401 151
- 401 170
- 401 171
- 401 176
- 401 178
- 401 179
- 401 180
- 401 181
- 417 460
- 417 466
-
International Classifications
-
Abstract
A dispensing device including a pump assembly for pumping out the viscous liquid material stored in the device. The pump has a cylinder and a piston disposed within the cylinder, wherein the cylinder includes a cylinder inlet valve and the piston includes a cylinder outlet valve. Each operation of the pump assembly causes the piston to move in a first direction toward the cylinder inlet valve and in a second direction away from the cylinder inlet valve. The movement of the piston in the first direction causes the cylinder inlet valve to close and the cylinder outlet valve to open. The movement of the piston in the second direction causes the cylinder inlet valve to open and the cylinder outlet valve to close. When the pump assembly is primed with viscous liquid material, movement of the piston in the first direction pumps a predetermined volume of the viscous liquid material from the cylinder through the opened cylinder outlet valve, thereby causing a substantially corresponding predetermined volume of the viscous liquid material to be dispensed by the device. Movement of the piston in the second direction draws a substantially corresponding predetermined volume of the viscous liquid material from the device into the cylinder through the opened inlet valve thereby refilling the cylinder with the viscous material.
Description
FIELD OF THE INVENTION
This invention relates to manually operated dispenser devices, and in particular, to a manually operated dispenser device for metering doses of viscous materials such as nail polish, lipstick, foundation, makeup and the like.
BACKGROUND OF THE INVENTION
There are many known dispenser devices for dispensing viscous material. Such devices have been employed in a variety of applications for discharging many different types of viscous materials. A common application for dispensers of this kind is in the field of cosmetic applicators. Typical cosmetic applicators are pen-like in design and dispense a cosmetic fluid onto an integrally disposed applicator when actuated by the user.
Pen-like fluid dispensing devices for manual user operation, especially those devices used for dispensing cosmetic fluids, must be capable of being fabricated inexpensively from readily available materials. In addition to the importance of minimizing manufacturing costs, it is equally important that such devices be fabricated to close tolerances in order to ensure proper fit and cooperative inter-engagement between both fixed and relatively movable parts, and to provide for reliable operation of the dispenser throughout its intended useful life which is usually until the initial supply of stored fluid is exhausted. In the case of cosmetic fluid dispensers, assuring continued operative reliability is much more difficult. This is because cosmetic fluids such as nail enamels, are relatively caustic to many common construction materials and quickly thicken and harden in the absence of adequate fluid tight seals, makes continued operative reliability much more difficult.
Typical known and commercially available dispenser devices commonly employ relatively complex mechanical designs which use large numbers of mutually engaging parts that must all cooperatively interact in order for the device to operate. Dispenser devices of this type are usually difficult and expensive to manufacture and often exhibit high failure rates as the devices approach the end or latter portion of their intended, useful lives. Moreover, many of these devices are difficult to operate.
Accordingly, there is a need for a dispenser device for dispensing metered doses of viscous material with enhanced reliability and ease of operation.
SUMMARY OF THE INVENTION
A dispensing device comprising a pump assembly for pumping out the viscous liquid material stored in the device. The pump includes a cylinder and a piston disposed within the cylinder, wherein the cylinder has a cylinder inlet valve and the piston has a cylinder outlet valve. Each operation of the pump assembly causes the piston to move in a first direction toward the cylinder inlet valve and in a second direction away from the cylinder inlet valve. The movement of the piston in the first direction causes the cylinder inlet valve to close and the cylinder outlet valve to open. The movement of the piston in the second direction causes the cylinder inlet valve to open and the cylinder outlet valve to close. When the pump assembly is primed with viscous liquid material, movement of the piston in the first direction pumps a predetermined volume of the viscous liquid material from the cylinder through the opened cylinder outlet valve, thereby causing a substantially corresponding predetermined volume of the viscous liquid material to be dispensed by the device. Movement of the piston in the second direction draws a substantially corresponding predetermined volume of the viscous liquid material from the device into the cylinder through the opened inlet valve thereby refilling the cylinder with the viscous material.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages, nature and various additional features of the invention will appear more fully upon consideration of the illustrative embodiments now to be described in detail in connection with accompanying drawings wherein:
FIG. 1
is a sectional view of a device for dispensing metered doses of viscous material according to an embodiment of the invention;
FIG. 2A
is a sectional view of the pump assembly of the device of
FIG. 1
;
FIG. 2B
is a detailed sectional view the pump housing of the pump assembly;
FIG. 3
is a detailed sectional view of the cylinder of the dispensing pump;
FIGS. 4A and 4B
are detailed elevational views of the needle sealing element of the dispensing pump;
FIGS. 5A and 5B
are detailed elevational views of the diaphragm member of the dispensing pump;
FIGS. 6A and 6B
are detailed elevational views of the biasing element of the dispensing pump;
FIG. 7A
is a detailed sectional view of the pump piston of the dispensing pump;
FIGS. 7B and 7C
are detailed elevational views of the pump piston of the dispensing pump;
FIGS. 8A and 8B
are detailed elevational views of the button of the dispensing pump;
FIG. 9A
is a detailed sectional view of the applicator holder of the applicator assembly;
FIG. 9B
is a detailed elevational view of the applicator holder of the applicator assembly;
FIGS. 10A and 10B
are detailed elevational views of the applicator member of the applicator assembly;
FIG. 10C
is a detailed sectional view of the applicator member of the applicator assembly;
FIGS. 11
,
11
B, and
11
C are detailed sectional views of the transfer tube of the applicator assembly;
FIG. 12A
is a detailed sectional view of the passive piston of the reservoir assembly;
FIG. 12B
is a detailed elevational view of the passive piston of the reservoir assembly; and
FIGS. 13A and 13B
are sectional views of the device depicting its operation.
It should be understood that these drawings are for purposes of illustrating the concepts of the invention and are not to scale.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1
shows a sectional view of a device
10
for dispensing metered doses of viscous material according to an embodiment of the invention. The device
10
generally comprises an applicator assembly
16
disposed at a forward end
12
thereof, a reservoir assembly
18
disposed at a rearward end thereof
14
, and a pump assembly
20
disposed between the applicator assembly
16
and the reservoir assembly
18
. The device
10
is typically pen-like in design, however, other embodiments of the device can be configured to be shorter and wider if desired.
FIG. 2A
shows a sectional view of the pump assembly
20
of the device
10
. The pump assembly
20
includes an opened ended, elongated cylindrical pump housing
21
which contains a dispensing pump
22
. As shown in the sectional view of
FIG. 2B
, the pump housing
21
has an axial bore
23
and a side wall aperture
24
that opens into the bore
23
. A button hinge flange
61
is provided just below the forward end of the pump housing aperture
24
. The forward end of the pump housing
21
is conventionally adapted for retaining the applicator assembly
16
therein and the rearward end of the pump housing
21
includes an internal screw thread
25
for threadedly connecting the reservoir assembly
18
. The inner surface of the pump housing
21
includes an annular locating groove
26
and a flange
40
both formed adjacent the forward end of the thread
25
.
Referring again to
FIG. 2A
, the dispensing pump
22
generally comprises a cylinder
27
, a needle sealing element
28
mounted in the cylinder
27
, a pump piston
29
reciprocally disposed in the cylinder
27
, a biasing element
30
positioned in the cylinder
27
between the pump piston
29
and the needle sealing element
28
, a flexible circular diaphragm member
46
disposed between the sealing element
28
and the cylinder
27
and a button
31
for finger operation of the pump
22
.
FIG. 3
shows a detailed sectional view of the cylinder
27
of the dispensing pump
22
. The cylinder
27
has an open forward end
32
and a closed rearward end
33
. The inner surface
34
of the cylinder
27
at its forward end
32
tapers outwardly to allow insertion of the pump piston
29
during assembly of the pump
22
. The closed rearward end
33
of the cylinder
27
includes a centrally located inlet orifice
39
. The inner surface
34
of the cylinder
27
adjacent the closed end
33
thereof includes an annular seating flange
35
for mounting the needle sealing element
28
. The outer surface
36
of the cylinder
27
adjacent the forward open end
32
thereof, has an annular locking bead
37
and a flange
38
which together coact with the pump housing's interior locating groove
26
and flange
40
arrangement to mount the cylinder
27
within the axial bore
23
of the pump housing
21
. When mounted, the rearward end
33
of the cylinder
27
extends beyond the rearward end of the pump housing
21
into the reservoir assembly
18
as shown in FIG.
1
.
FIGS. 4A and 4B
show detailed elevational views of the needle sealing element of the dispensing pump
22
. The needle sealing element
28
includes a base
41
with a plurality of radially extending spokes
42
disposed at the rearward end of the base
41
and a shaft
43
extending from the forward end of the base
41
. The spokes
42
of the needle sealing element
28
rest on the seating flange
35
of the cylinder
27
when the element
28
and the cylinder
27
are assembled. The rearward end of the base
41
further includes a centrally located aperture
45
. The forward end of the shaft
43
includes an enlarged, forwardly tapered sealing member
44
.
FIGS. 5A and 5B
show detailed elevational views of the diaphragm member
46
of the dispensing pump
22
. The diaphragm member
46
includes a unitarily formed centrally located mounting post
47
which is slidably received in the aperture
45
of the needle sealing element base
41
. The mounting post
47
aligns the diaphragm member
46
with the cylinder inlet orifice
39
thus, forming a cylinder inlet valve
48
(
FIG. 2A
) as will be explained further on.
The pump piston
29
of the dispensing pump
22
is shown in detail in the sectional view of FIG.
7
A and the elevational views of
FIGS. 7B and 7C
. The pump piston
29
comprises an elongated tubular member having an outer surface
107
, an inner surface
49
, an open forward end
50
and an outwardly flared rearward end
51
. The inner surface
49
of the pump piston
29
adjacent the rearward end
51
thereof is occluded by a partition member
52
. The partition member
52
includes an outlet orifice
53
with an annular beveled sealing surface
54
on its forward side and an annular recess
57
on its rearward side. The outer surface
107
of the pump piston
29
includes a pair of cam surfaces
55
which are formed on opposite sides thereof. The cam surfaces
55
are disposed at an angle θ measured from the longitudinal axis A of the pump piston
29
, this angle θ typically measuring between about 40 and 50 degrees. The cam surfaces
55
coact with the button
31
positioned within the aperture
24
of the pump housing
21
as will be explained further on in greater detail. The cam surfaces
55
are connected by an arcuate support member
106
that engages the inner surface of the pump housing
21
(
FIG. 2A
) to prevent bending of the pump piston
29
when actuated by the button
31
.
As shown in
FIG. 2A
, the rearward end
51
of the piston
29
fits into the open end
32
of the cylinder
27
, such that the rearward end
51
of the piston
29
sealingly engages the inner surface of the cylinder
27
. Further, the sealing member
44
of the needle sealing element
28
extends through the outlet orifice
53
of the piston
29
thereby defining a cylinder outlet valve
56
.
FIGS. 6A and 6B
show detailed elevational views of the biasing element
30
of the dispensing pump
22
. The biasing element
30
typically comprises a conventional hectically wound coil metal or plastic spring. As shown in
FIG. 2A
, the biasing element
30
is disposed in the cylinder
27
such that the forward end of the spring is seated in the recess
57
defined in the partition member
52
of the pump piston
29
and the rearward end of the spring is seated on the spokes
42
of the needle sealing element
28
. Thus, in a non-dispensing mode (FIG.
1
), the biasing element
30
biases the beveled sealing surface
54
of the pump piston outlet orifice
53
against the sealing member
44
of the needle sealing element
28
thereby closing the cylinder outlet valve
56
(FIG.
2
A).
FIGS. 8A and 8B
show detailed elevational views of the button
31
of the dispensing pump
22
. The button
31
has a upside-down U-shaped cross-section formed by a generally convex top wall
58
and a pair of parallel spaced side walls
59
. Slots
60
are formed in the forward edges of the side walls
59
. The slots
60
permit the button
31
to pivot on the hinge flange
61
of the pump housing aperture
24
while the rearward corners
62
of the button side walls
59
slidingly engage the cam surfaces
55
of the pump piston
29
. A pair of elongated projections
63
are provided on the outer surface of each button side wall
59
. The projections
63
engage the inner surface of the pump housing
21
to prevent the button
31
from being separated from the pump housing
21
.
Referring again to
FIG. 1
, the applicator assembly
16
includes an applicator holder
64
, an applicator member
65
disposed in the holder
64
, a transfer tube
66
inserted in the applicator member
65
, a second flexible circular diaphragm member
89
disposed between the transfer tube
66
and applicator member
65
and a removable closure
67
for sealingly covering the applicator member
68
.
The applicator holder
64
of the applicator assembly
16
is shown in detail in the sectional view of FIG.
9
A and the elevational view of
9
B. The applicator holder
64
has a generally cylindrical an outer surface
69
and a stepped cylindrical inner surface
70
. The outer surface
69
tapers at
72
toward the inner surface
70
at the forward end
71
of the holder
64
. An annular bead
73
for snap-engaging the closure
67
to the applicator assembly
16
, is provided on the outer surface
69
adjacent the tapered outer sealing surface
72
. The outer surface
69
includes two annular barb projections
75
at the rearward end
74
of the holder, for fixing the applicator assembly
16
in the forward end of the pump housing axial bore
23
. A circumferential flange
76
on the outer surface
69
of the holder
64
abuts against the edge of the pump housing
21
to prevent the holder
64
from being pushed into the housing
21
during use.
The applicator member
65
of the applicator assembly
16
is shown in detail in the elevational views of
FIGS. 10A and 10B
, and the sectional view of FIG.
10
C. The applicator member
65
has a generally cylindrical stepped outer surface
77
. The outer surface
77
defines a pair of converging beveled surfaces
78
at the forward end
79
of the member
65
which function as dispensing contact surfaces. The applicator member
65
includes an interior bore
80
that extends forwardly from the rearward end
81
thereof to an annular channel
82
which then branches off into a pair of smaller, concentrically arranged inner and outer annular channels
84
,
85
that communicate with the beveled surfaces
78
. In other embodiments of the device, the applicator member can be conventionally configured as a brush, a ball carrying member, one or more dispensing ports and the like.
The details of the transfer tube
66
of the applicator assembly
16
are shown in the sectional views of
FIGS. 11A
,
11
B, and
11
C. The transfer tube
66
has a forward open end
86
and a rearward open end
87
. Four equally-spaced lugs
88
are formed on the interior at the forward end
86
of the tube
66
. The lugs
88
secure the second diaphragm member
89
(shown in detail in
FIG. 11B
) to the transfer tube
66
by the member's
89
mounting post
90
.
As shown in
FIG. 1
, the forward open end
86
of the transfer tube
66
is fixedly disposed in the bore
80
at the rearward end of the applicator member
65
and the rearward open end
87
extends into the forward open end
50
of the pump piston
29
. The second flexible circular diaphragm member
89
selectively opens and closes the forward open end
86
of the transfer tube
66
as will be explained further on.
Referring still to
FIG. 1
, the removable closure
67
of the applicator assembly
16
includes an outer cap member
100
and an inner cap member
101
. The outer cap member
100
includes annular inner bead
102
which cooperates with the annular outer bead
73
of the applicator holder
64
to snap lock of the closure
67
to the applicator assembly
16
. The inner cap member
101
includes a sealing surface
103
which engages the tapered sealing surface
72
of the applicator holder
64
to prevent leakage of viscous material from the applicator assembly
16
.
Referring still again to
FIG. 1
, the reservoir assembly
18
includes an elongated, open-ended cylindrical reservoir member
91
, a passive piston
92
disposed in the rearward end of the reservoir member
91
, and an end cap
93
fixed in the rearward end of the reservoir member
91
. The forward end of the reservoir includes an external thread
94
which threadedly engages the internal thread
25
at the rearward end of the pump housing
21
to attach the reservoir assembly
18
thereto. In other embodiments of the invention, the reservoir assembly
18
and the pump housing
21
can be a single unitary member.
The details of the passive piston
92
of the reservoir assembly
18
is shown in the sectional view of FIG.
12
A and the elevational view of
12
B. The passive piston
92
includes an outwardly flared cup-like forward end
95
and an outwardly flared cup-like rearward end
96
which both share a common base wall
97
. A cylindrical projection
98
extends rearwardly from within the base wall
97
.
The operation of the device
10
will now be described with reference to
FIGS. 13A and 13B
. The operational description assumes that the device has been primed, i.e., viscous material
105
to be dispensed has been drawn into the cylinder
27
, the transfer tube
66
, and the applicator member
65
from the reservoir assembly
18
.
As shown in
FIG. 13A
, dispensing commences when the button
31
of the dispensing pump
22
is pressed. As the button
31
pivots through the aperture
24
, the rearward corners
62
of the button sidewalls
59
slidably engage the cam surfaces
55
(shown with broken lines) of the pump piston
29
, causing it to move rearwardly further into the cylinder
27
, thereby compressing the biasing element
30
. The cylinder volume reduction caused by the pump piston's
29
rearward movement into the cylinder produces a positive pressure in the cylinder
27
which closes the cylinder inlet valve
48
formed by the diaphragm member
46
and the cylinder inlet orifice
39
. The rearward movement of the pump piston
29
also opens the cylinder outlet valve
56
formed by the needle sealing element
28
and the pump piston outlet orifice
53
. These valving changes forces or meters a certain volume or dose of viscous material
105
contained in the cylinder
27
out the pump piston outlet orifice
53
into the rearward end
87
of the transfer tube
66
. The metered volume of viscous material
105
is generally determined by the rearward stroke distance of the pump piston
29
and the area of the cylinder
27
.
The flow of the metered volume of viscous material
105
causes the entire column of viscous material in the transfer tube
66
and applicator member
65
to flow forwardly. The viscous material flow in the transfer tube
66
opens the second diaphragm member
89
sealing the forward open end
86
of the transfer tube
66
thus, permitting a correspondingly similar volume of viscous material
105
to flow from the transfer tube
66
into the channels
82
,
84
,
85
of applicator member
65
and out onto the member's beveled outer surfaces
78
.
When the pump piston
29
reaches the end of its rearward stroke, viscous material flow ceases and the second diaphragm member
89
automatically reseals the forward open end
86
of the transfer tube
66
. When the button
31
is released as shown in
FIG. 13B
, the biasing force exerted by the biasing element
30
on the pump piston
29
forwardly moves the pump piston
29
to its original shallow position in the cylinder
27
. This forward movement of the pump piston
29
creates a negative pressure or vacuum in the cylinder
27
which opens the cylinder inlet valve
48
. Because rearward end of the cylinder
27
is immersed in the viscous material
105
stored in the reservoir member
91
, the vacuum draws this viscous material
105
into the cylinder
27
, thereby refilling it. As the viscous material
105
in the reservoir member
91
moves forwardly during refilling of the cylinder
27
, it creates a vacuum which moves the passive piston
92
forwardly thus, keeping the rearward end of the cylinder
27
immersed in the viscous material
105
.
While the foregoing invention has been described with reference to the above embodiments, various modifications and changes can be made without departing from the spirit of the invention. Accordingly, all such modifications and changes are considered to be within the scope of the appended claims.
Claims
- 1. A dispensing device comprising:a pump assembly for pumping out the viscous liquid material stored in the device, the pump including a cylinder and a piston disposed within the cylinder, the cylinder having a cylinder inlet valve orifice and the piston having a cylinder outlet valve orifice, wherein each operation of the pump assembly causes the piston to move in a first direction toward the cylinder inlet valve orifice and in a second direction away from the cylinder inlet valve orifice, the movement of the piston in the first direction causing the cylinder inlet valve orifice to be closed and the cylinder outlet valve orifice to be opened, the movement of the piston in the second direction causing the cylinder inlet valve orifice to be opened and the cylinder outlet valve orifice to be closed; wherein, when the pump assembly is primed with viscous liquid material, movement of the piston in the first direction pumps a predetermined volume of the viscous liquid material from the cylinder through the opened cylinder outlet valve orifice, thereby causing a substantially corresponding predetermined volume of the viscous liquid material to be dispensed by the device, and the movement of the piston in the second direction draws a substantially corresponding predetermined volume of the viscous liquid material from the device into the cylinder through the opened inlet valve orifice thereby refilling the cylinder with the viscous material.
- 2. The dispensing device according to claim 1, further comprising a reservoir assembly for storing a viscous liquid material, wherein a portion of the pump assembly becomes partially immersed in the viscous liquid material when the same is stored in the reservoir assembly.
- 3. The dispensing device according to claim 2, wherein the reservoir assembly includes a piston for keeping the portion of the pump assembly partially immersed in the viscous liquid material when the same is stored in the reservoir assembly.
- 4. The dispensing device according to claim 2, wherein the reservoir assembly includes an elongated cylindrical reservoir, the cylinder is disposed within an open end of the reservoir, the cylinder forming the portion of the pump assembly partially immersed in the viscous liquid material when the same is stored in the reservoir.
- 5. The dispensing device according to claim 4, wherein the pump assembly is disposed within a cylindrical housing that is coupled to the reservoir of the reservoir assembly.
- 6. The dispensing device according to claim 5, wherein the button is pivotally mounted to cylindrical housing.
- 7. The dispensing device according to claim 1, further comprising an applicator assembly for dispensing the viscous liquid material pumped by the pump assembly, the applicator assembly in communication with the cylinder outlet valve orifice of the piston.
- 8. The dispensing device according to claim 7, wherein the applicator assembly includes a closure.
- 9. The dispensing device according to claim 7, wherein the applicator assembly includes an applicator and a tube extending from the applicator toward the piston and engaged therewith, the tube for transferring viscous liquid material from the cylinder outlet valve orifice of the piston to an external dispensing surface of the applicator.
- 10. The dispensing device according to claim 9, wherein the tube includes an outlet valve orifice.
- 11. The dispensing device according to claim 10, wherein the outlet valve orifice is opened when the piston moves in the first direction and closed when the piston moves in the second direction.
- 12. The dispensing device according to claim 1, wherein the pump assembly further includes a finger operable button which coacts with the piston to cause the piston to move in the first and second directions.
- 13. The dispensing device according to claim 12, wherein the piston includes a cam surface which is slidably engaged by the button to cause the piston to move in the first and second directions.
- 14. The dispensing device according to claim 12, wherein the button is pivotally mounted to the pump assembly.
- 15. The dispensing device according to claim 14, wherein the piston includes a cam surface which is slidably engaged by a pivoting end of the button, such that as the pivoting end of the button slides along the cam surface in a first direction, the piston to moves in one of the first and second directions, and as the pivoting end of the button slides along the cam surface in a second direction, the piston to moves in the other one of the first and second directions.
- 16. The dispensing device according to claim 1, further comprising a biasing element disposed between the cylinder and the piston for biasing the piston in the second direction.
- 17. A dispensing device comprising:a pump assembly for pumping out the viscous liquid material stored in the device, the pump including a cylinder and a piston disposed within the cylinder, the cylinder having a cylinder inlet valve orifice and the piston having a cylinder outlet valve orifice, wherein each operation of the pump assembly causes the piston to move in a first direction toward the cylinder inlet valve and in a second direction away from the cylinder inlet valve, the movement of the piston in the first direction causing the cylinder inlet valve orifice to close and the cylinder outlet valve orifice to open, the movement of the piston in the second direction causing the cylinder inlet valve orifice to open and the cylinder outlet valve orifice to close; a reservoir assembly for storing a viscous liquid material, the pump assembly having a portion that becomes partially immersed in the viscous liquid material when the same is stored in the reservoir assembly; and an applicator assembly for dispensing the viscous liquid material pumped by the pump assembly, the applicator assembly in communication with the cylinder outlet valve orifice of the piston; wherein, when the pump assembly is primed with viscous liquid material, movement of the piston in the first direction pumps a predetermined volume of the viscous liquid material from the cylinder through the opened cylinder outlet valve orifice, thereby causing a substantially corresponding predetermined volume of the viscous liquid material to be dispensed by the applicator assembly, and the movement of the piston in the second direction draws a substantially corresponding predetermined volume of the viscous liquid material from the reservoir assembly into the cylinder through the opened inlet valve orifice thereby refilling the cylinder with the viscous material.
- 18. The dispensing device according to claim 17, wherein the pump assembly further includes a finger operable button which coacts with the piston to cause the piston to move in the first and second directions.
- 19. The dispensing device according to claim 18, wherein the piston includes a cam surface which is slidably engaged by the button to cause the piston to move in the first and second directions.
- 20. The dispensing device according to claim 18, wherein the button is pivotally mounted to the pump assembly.
- 21. The dispensing device according to claim 20, wherein the piston includes a cam surface which is slidably engaged by a pivoting end of the button, such that as the pivoting end of the button slides along the cam surface in a first direction, the piston to moves in one of the first and second directions, and as the pivoting end of the button slides along the cam surface in a second direction, the piston to moves in the other one of the first and second directions.
US Referenced Citations (14)