Abstract:
A continuous, extended spray pump which has two opposing and coaxial chambers. The upper chamber is fitted with an upper and middle piston urged upwardly by a spring, and the lower chamber is fitted with an opposing piston urged upwardly by a spring. A port connects the space between the two upper pistons with the external atmosphere, and a one-way check valve controls the liquid flow between the upper and lower chambers.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to finger operated spray pumps. In particular this invention relates to a spray pump that upon repeated actuation will produce a continuous discharge. 
     2. Description of the Prior Art 
     Many conventional spray pumps produce a spray which varies in pressure and volume in proportion to the force applied by the finger of the user actuating the pump. If the force applied by the finger is relatively small, the spray will not be highly atomized. 
     To achieve rapid atomization and the production of a high degree of atomization of the spray, double cylinder-double piston pumps, sometimes known as accumulative pressure pumps, have been developed. Such pumps usually have a dual-diameter pump chamber or body, generally the upper portion being a larger diameter than the lower portion. Separate pistons are provided in each of the different diameter portions, which pistons move together on downstroke and produce accumulation of pressure in the two chambers resulting in disengagement of the outlet valve whereby fluid is expressed through the atomizer nozzle at an instantaneously high pressure to produce fine atomization from the start of the spray until the end thereof. Accumulative pressure pumps having interconnected, different diameter pump chambers or bodies are shown in U.S. Pat. Nos. Re. 28,366; 3,746,260; 3,761,022; 3,796,375; 3,865,313; 3,907,206; 3,908,870; 3,921,861; 3,923,250; 3,940,030; 4,017,031; and 4,051,983. 
     In many applications it is desired to have a finger operated spray pump which will produce a continuous, extended spray even after the finger is removed from the pump in addition to the rapid and high atomization characteristic of accumulative pressure pumps. Furthermore, in some applications it is desirable to have a spray pump which will produce a continuous spray of relatively constant pressure as the spray button is repeatedly depressed and released, even though the button is not being fully depressed. 
     U.S. Pat. No. 3,761,022, issued to Kondo, is directed to an accumulative pressure finger operated spray pump. However, the Kondo pump does not have a continuous extended spray because when Kondo&#39;s plunger is no longer in its extreme innermost position, the outlet orifice no longer communicates with the pressurized liquid. 
     THE INVENTION 
     In accordance with the present invention there is provided a continuous, extended spray pump which has two opposing and coaxial chambers. The upper chamber is fitted with an upper and middle piston urged upwardly by a spring, and the lower chamber is fitted with an opposing piston urged upwardly by a spring. A port connects the space between the two upper pistons with the external atmosphere, and a one-way check valve controls the liquid flow between the upper and lower chambers. 
     A prime advantage of the present invention is that upon repeated actuation the pump will produce an extended, continuous, highly atomized discharge. Another important advantage is that any leakage that may occur will flow from the bottom of the pump into the fluid container. The discharge remains relatively uniform and does not vary substantially with the pressure exerted on the actuator or the timing between depression of the actuator. The spray pump will continue to spray after the finger is removed from the actuator. 
     The above advantages and other advantages will become apparent in the following drawings and description of the preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partly cross-sectional, partly cut-away, elevational view of the pump of the present invention prior to actuation; 
     FIG. 2 is a partly cross-sectional, partly cut-away, elevational view of the pump of the present invention as the actuator is being depressed; 
     FIG. 3 is a partly cross-sectional, partly cut-away, elevational view of the pump of the present invention as the actuator is being released; 
     FIG. 4 is a partly cross-sectional, partly cut-away, elevational view of the pump of the present invention as the actuator continues to discharge after the actuator has been released and is fully extended; 
     FIG. 5 is a top plan view of the middle piston of the present invention; 
     FIG. 6 is an elevational view of the middle piston of the present invention; 
     FIG. 7 is a top view of the one-way check valve of the present invention; 
     FIG. 8 is an elevational view of the one-way check valve of the present invention; 
     FIG. 9 is a top plan view of the inner cylindrical housing of the present invention; and, 
     FIG. 10 is an elevational view of the inner cylindrical housing of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, in FIG. 1 is shown a preferred embodiment of the continuous, extended spray pump of the present invention prior to actuation. The pump is contained in a generally cylindrical outer housing 10. At the upper end of housing 10 is inserted an inner cylindrical housing generally indicated by the numeral 12. Inner housing 12 is shown in greater detail in FIGS. 9 and 10. Located in the side of housing 12 is an orifice 14 through which liquid can flow. 
     Ports 18 are located in the lower end of housing 12 and extend through the base thereof. Located adjacent to ports 18 in the interior of housing 12 are nibs 20 having upper beveled edges 22. At the lower end of the interior of housing 12 is an inlet channel 24 which contains ball check valve 26. Ball check valve 26 is held in the inlet by a series of flexible tabs 28 which allow the ball to be forced into the inlet. A dip tube 30 is inserted into the cylindrical lower end 32 of housing 12 and extends through hole 33 in the bottom of housing 10 to a liquid reservoir or container (not shown). 
     Located immediately beneath housing 12 is a one-way check valve generally indicated by the numeral 34 which can best be seen in FIGS. 7 and 8. One-way check valve 34 has a flexible lower lip 36 which flexes as shown in FIG. 2 to allow liquids under pressure in the interior of housing 12 to flow through ports 18. Flexible lip 36 is aligned to seal the bottom of ports 18 in inner housing 12 on the upstroke of the actuator as shown in FIG. 3. 
     Also located in the bottom of valve 34 is circular hole 35 shown in FIG. 7. The lower end 32 of inner cylindrical housing 12 is fitted into hole 35 as shown in FIG. 1. 
     A recess 46 in check valve 34 allows liquid to flow upwards therethrough to orifice 14. A circular lip 48 surrounds the upper outside of check valve 34 to provide a liquid seal against the interior of housing 10. 
     Located immediately beneath check valve 34 is a bottom piston generally indicated by the numeral 50. Bottom piston 50 has a hollow cylindrical passage 52 in the center thereof which forms a sliding seal with the lower end 32 of housing 12. The upper outer wall 54 of bottom piston 50 forms a sliding seal with the inner wall of housing 10. A circular shoulder 56 strikes the bottom edge of check valve 34 to limit the upper movement of bottom piston 50. The lower end of outer housing 10 fits loosely about dip tube 30 and does not form a seal with the lower end 32 of inner housing 12 so that air may be free to flow in and out of hole 33 in the lower end of outer housing 10 as lower piston 50 travels upwardly and downwardly. Also, any leakage that may occur will flow out of hole 33 into the liquid container (not shown). 
     Bottom piston 50 is biased upwardly by spring 58 which strikes the bottom 53 of bottom piston 50 and the bottom of housing 10. A series of nibs 60 located in the bottom interior of housing 10 limits the downward movement of bottom piston 50 when the lower shoulders 62 of bottom piston 50 strikes the nibs. 
     Located in the upper end of housing 12 are upper piston 64, shown in FIGS. 1-4, and a middle piston generally indicated by the numeral 66, shown in FIGS. 1-6. Upper piston 64 is an inverted cup-shaped piston having outer walls 69 which form a sliding seal with the interior of housing 12. Integrally molded with piston 64 is hollow stem 70 having an inner cylindrical discharge channel 72 through which liquid can flow. A typical button actuator or nozzle 73 is attached to the upper end of stem 70. 
     Immediately beneath and partly contained in upper piston 64 is middle piston 66. If desired, upper piston 64 and middle piston 66 can be molded as one piece or they may be molded as two pieces and rigidly fastened together by gluing or the like. Middle piston 66 is biased upwardly by spring 74 which presses against the bottom 76 of the interior of housing 12. Middle piston 66 has an outer wall 78 which forms a sliding seal with the interior wall of housing 12. As can be seen in FIG. 4, orifice 14 is positioned so that liquids can flow therethrough into the interior of inner housing 12 even when middle piston 66 is in the uppermost, or undepressed, position. 
     A recess 80 is formed in the bottom of middle piston 66 to snuggly receive spring 74. A stem 82 projects upwardly from middle piston 66 and has three channels 84 formed therein. Channels 84 align with channel 72 and stem 70 to permit liquids to flow upwardly from the interior of housing 12 into channel 72. 
     To operate the pump of the present invention, the button 73 on top of stem 70 is depressed by the finger of the operator, as shown in FIG. 2, and causes the upper piston 64 and middle piston 66 to move downwardly. Middle piston 66 forces air out of the interior of housing 12 beneath piston 66 outwardly through ports 18 causing lip 36 to flex downwardly and air to flow out of housing 12. Air passing around check valve 34 moves lower piston 50 downward slightly and flows upwardly through slot 46 and through orifice 14. From orifice 14 air flows upwardly through the interior of housing 12 through channels 84 and outwardly through channel 72 to the dispensing button 73. The remaining pressurized air in housing 12 beneath middle piston 66 is vented when the side wall 78 of middle piston 66 strikes the top of nibs 20 in inner housing 12 and is deflected allowing the air to flow past side wall 78 and through channels 84 and 72. 
     The pump is primed on the return stroke, as shown in FIG. 3, as check valve 34 seals ports 18 in housing 12 and ball check valve 26 floats upwardly to allow fluids to travel up dip tube 30. Once primed, on the next down stroke, as shown in FIG. 2, liquid is forced through ports 18 and around check valve 34 into the interior of housing 10 beneath check valve 34 thus forcing lower piston 50 downward against the pressure of spring 58. Fluids flow upwardly when piston 50 is moved downwardly through orifice 14 into the interior of housing 12. Liquids continue to flow upwardly through channels 84 and channel 72 and out through the nozzle on stem 70 to the atmosphere. Short, light strokes are sufficient to keep liquids flowing. As shown in FIG. 4, liquids will continue to flow as long as lower piston 62 is depressed beneath check valve 34 even when the finger is removed since orifice 14 is not sealed by middle piston 66 even in the released position. The terminal orifice of the discharge button is chosen to have a lower flow rate than the flow of liquid into the chamber beneath check valve 34 so that a portion of the liquid is discharged and the remainder causes the lower piston to be displaced downward. 
     On the up stroke, shown in FIG. 3, of the upper and middle pistons, liquid is pulled up the dip tube 30 past ball check valve 26 to refill the upper chamber. Liquid in the portion of housing 10 beneath check valve 34 is prevented from entering the interior of housing 10 beneath lower piston 66 by check valve 34 and continues to flow through orifice 14 and channels 84 and 72 to the dispensing button because pressure is being applied to the liquid by spring 58 which forces piston 50 upwardly. If the discharge orifice is chosen appropriately, repeated depressions of stem 70 will maintain the liquid in housing 10 beneath check valve 34 under pressure at all times producing a continuous, extended spray discharge. If the pump, after priming, is actuated only once it will act as an extended spray pump discharging until the lower chamber is empty. 
     Check valve 34 may be held in place on the bottom of inner housing 12 by any desired conventional means. For example, circular lip 48 may be force-fitted against the inside wall of outer housing 10 to hold the check valve 34 in place. 
     The pump of the present invention may be fastened to any container desired. When fastened to a container, air must be allowed to enter the container as fluids are pumped therefrom. Air can be permitted to enter the container by loosely fitting the pump onto the container, or by any other means known in the art. 
     Although the preferred embodiments of the present invention have been disclosed and described in detail above, it should be understood that the invention is in no sense limited thereby and its scope is to be determined by that of the following claims.