This invention relates to the art of handheld fluid dispensers and, more particularly, to improvements in the pump drive unit of a battery operated, handheld fluid dispenser.
A battery operated, motorized fluid dispenser of the character to which the present invention is directed is shown, for example, in U.S. Pat. No. 5,716,007 to Nottingham, et al. which is assigned to the same assignee as the present invention and which is hereby incorporated herein by reference. In the latter dispenser, an electric motor is selectively connected to a battery source by a push button or trigger operated switch and, when energized, the motor operates a pump mechanism by which fluid in a supply container associated with the dispenser is pumped through a discharge opening.
While the battery operated dispenser in the Nottingham, et al. patent operates satisfactorily, component parts in the pumping mechanism are subjected to forces and frictional interengagement which causes undesirable wear of the parts, undesirable loading of the electric motor, and undesirably fast drainage of the batteries. More particularly in this respect, the pump driving arrangement includes an electric motor having an output shaft coaxial with the pump and carrying a cam which is cooperable with an aligned cam follower on the movable component of the pump such that rotation of the motor output shaft is translated into axial displacement of the follower and pump element in a cylinder portion of the pump. Each of the aligned cam and cam follower has a planar cam surface inclined at the same angle relative to the drive shaft and pump axes and coaxial therewith. The cam follower associated with the pump element is restrained against rotation relative to the motor shaft and pump axes, whereby the cam face on the cam component mounted on the motor shaft rotates relative to the cam face of the cam follower between full facial engagement therewith when the pump element is at one end of the stroke thereof and engagement of the radially outer edges of the axially outer ends of the cam and follower components when the pump element is at the other end of the stroke thereof. The interengaging relationship between the cam faces during relative rotation therebetween radially loads the drive motor shaft and the cam follower and pump element, and radially loads the interengaging portions of the cam faces during relative rotation therebetween. Such loading of the cam faces not only promotes wear therebetween but uneven wear. Moreover, radial loading of the cam follower urges the latter against the cylinder portion of the pump and, together with radial loading of the motor shaft, imposes loads on the motor which in turn causes undesirably high drainage of the batteries. All of these undesirable loading characteristics impose frictional interengagement between the parts which undesirably affects performance of the drive unit and pump element. Moreover, maintenance and/or part replacement resulting from wearing of the component parts and battery drainage is undesirably high.
In accordance with the present invention, battery operated fluid dispensers are provided with an improved pump drive unit by which the foregoing and other disadvantages are minimized or overcome. More particularly, in a pump drive unit according to the invention, the aligned cam and cam follower respectively associated with the electric motor and the pump element each have dual cam surfaces or faces cooperatively interengaging to achieve pump element displacement through the full stroke of the pump in a manner which provides balanced radial or lateral thrust forces on opposite sides of the motor shaft, cam follower and pump element. This relationship advantageously reduces not only the amount of wear between the cam components but the uneven wear thereof experienced with single cam face components. Moreover, balanced loading of the motor shaft, follower and pump element reduces undesirable loading of the electric motor and thus battery drain, thus providing a longer life for the drive system, improved battery life, and improved performance of the pump element.
Another improvement in accordance with the invention resides in providing rollers on laterally opposite sides of the cam follower which ride in corresponding slots in the cam follower support. The rollers and slots interengage to preclude rotation of the cam follower relative to its support, and the interengagement between the slots and rollers advantageously reduces friction between the component parts during axial movement of the cam follower.
It is accordingly and outstanding object of the present invention to provide improvements in connection with the pump and pump drive unit of a battery operated fluid dispenser.
Another object is the provision of a fluid dispenser pump drive unit comprising driving and driven cam components structured for thrust forces therebetween during operation of the pump to be balanced.
A further object is the provision of a pump drive unit of the foregoing character which provides for a more uniform wearing of the interengaging cam surfaces than achieved with cam drive arrangements heretofore provided.
Yet another object is the provision of a pump drive unit of the foregoing character providing improved performance of the pump during the operation of the pump.
Yet a further object is the provision of a pump drive unit of the foregoing character which reduces loading of the electric motor, thus increasing the life thereof and reducing battery drainage so as to improve battery life.
Still another object is the provision of a pump drive unit of the foregoing character which results in improved performance of the pump element during operation thereof.
The foregoing objects, and others, will in part be obvious and in part pointed out more fully hereinafter in conjunction with the written description of preferred embodiments of the invention illustrated in the accompanying drawings in which:
Referring now in greater detail to the drawings, wherein the showings are for the purpose of illustrating preferred embodiments of the invention only, and not for the purpose of limiting the invention,
As best seen in
Wall 34 includes an outlet opening 58 coaxial with axis 28, and the axially outer end of discharge tube portion 30 of body member 26 receives and supports a nozzle component 60 having a discharge outlet 62 coaxial with axis 28 and through which fluid from container 16 is pumped as will become apparent hereinafter. A discharge control valve element 64 is reciprocally supported in discharge tube portion 30 and has an inner end 66 adapted to move axially relative to opening 58 between engaged and disengaged positions relative to the axially outer edge of the opening which provides a valve seat for valve element 64. A spinner element 68 abuts against the inner side of nozzle member 60 and has an outer end coaxial with axis 28 and provided in a well-known manner with an axially inwardly extending recess 70 and ports 72 opening laterally thereinto so as to impart a swirling motion to fluid pumped through outlet tube portion 30 and thence through discharge opening 62. A biasing spring 74 is disposed between valve element 64 and spinner element 68 and, preferably, is integral therewith. Accordingly, it will appreciated that displacement of valve element 64 to the left from its position shown in
Body member 26 further includes an inlet conduit 76 integral with and extending downwardly therefrom, and an inlet opening 78 in the pump cylinder wall which communicates the interior of tube 76 with pump chamber 56. The lower end of inlet tube 76 receives the upper end of a dip tube 80 which extends downwardly into supply container 16 for delivering fluid from the container to the pump chamber during operation of the sprayer. The axially inner end of pump diaphragm wall 40 overlies inlet opening 78 and provides a check valve which permits fluid to enter pump chamber 56 from supply container 16 during the suction stroke of the pump and precludes the flow of fluid in pump chamber 56 through inlet opening 78 during the discharge stroke of the pump.
As mentioned hereinabove, axially inner end 48 of diaphragm actuator 46 interengages with the re-entrant portion of pump diaphragm 38 such that movable end 42 of the pump diaphragm is axially displaceable with the actuator member. As will be appreciated from
Pump drive unit 14 comprises an electric motor 94 having a rotatable output shaft 96 which is coaxial with axis 28 when the pump drive unit including housing 24 is mounted on supply container 16 in operative relationship with pumping unit 12. The outer end of shaft 96 is provided with a cam member 98 which is suitably secured to shaft 96 for rotation therewith. As will be described in greater detail hereinafter, cam 98 and cam follower 82 have cam faces interengaging to axially displace cam follower 82 and thus diaphragm end 42 in response to rotation of cam 98. Cam member 98 further includes a circular projection 102 coaxial with axis 28. Projection 102 extends axially outwardly from cam 98 and is axially slidably and rotatably received in bore 92 in cam member 82 for the purpose set forth hereinafter.
As will be appreciated from
In accordance with the present invention, and as best seen in
While considerable emphasis has been placed herein on the structures and structural interrelationships between the component parts of the preferred embodiments of the invention, it will be appreciated that other embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the invention. In particular in this respect, it will be appreciated that the pump member can be provided other than by the preferred diaphragm component and, for example, could be in the form of a reciprocable piston, and axially collapsible bellows member, or the like. Further, while the cam and cam follower components are disclosed as having dual cam faces to obtain balanced lateral forces therebetween, it will be appreciated that the components can provide this balanced force relationship with three, four or more interengaging faces and with cam face configurations other than those disclosed and, for example, with sinusoidal cam faces. The foregoing and other modifications of the preferred embodiment as well as other embodiments of the invention will be obvious or suggested to those skilled in the art, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.
This application claims priority from U.S. Provisional Patent Application Ser. No. 60/465,438 filed Apr. 28, 2003.
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Number | Date | Country | |
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20040211792 A1 | Oct 2004 | US |
Number | Date | Country | |
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60465438 | Apr 2003 | US |