Dispenser device for dispensing metered doses of viscous material

Information

  • Patent Grant
  • 6200055
  • Patent Number
    6,200,055
  • Date Filed
    Friday, June 18, 1999
    25 years ago
  • Date Issued
    Tuesday, March 13, 2001
    24 years ago
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.
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