Hand Operated Sprayer With Automatic Container Vent

1. Field of the Invention

A common problem with liquid spraying devices of the hand-operated type is the need for relief of the negative pressure created in the closed container on which the device is used as liquid is pumped. The vacuum created is relieved by venting atmospheric air into the container to displace the liquid dispensed. Various ways to do this have been proposed in the art and, in general, usually involve separate or discrete value means with or without a vent passage, and more often than not, are difficult to construct and are expensive. In addition, prior art devices are often cumbersome to use and operate.

It is also very important that the device not leak when the trigger or actuator is at rest and the container and sprayer are laid on a side or even inverted such as might be the case in normal use in spraying or in shipment where a full container might be supplied with the device when sold.

2. Description of the Prior Art

A number of patents have been issued on trigger-piston type hand sprayers useful for dispensing liquid from containers. For example, a particularly useful, and perhaps the basic, trigger type sprayer is disclosed in U.S. Pat. No. 3,061,202, issued on Oct. 30, 1962 to Tracy B. Tyler wherein venting is provided by means of a separate valve biased in the normally open position. Other patents disclosing similar sprayers also using discrete valve means for venting are U.S. Pat. No. 3,650,473, issued on Mar. 13, 1972 to Carl E. Malone, U.S. Pat. No. 3,685,739, on Aug. 22, 1972 to Vance R. Vanier, and U.S. Pat. No. 3,780,951, on Dec. 25, 1973 to Richard T. Powers. The first mentioned Malone patent vents in a manner similar to the Tyler device while the patent to Powers shows an atmospheric vent through the body of the sprayer where it attaches to the container but has a collar which is screwed down by the operator into an annular slot to close it off and thus prevent leakage of liquid from the container. Second mentioned patent to Vanier utilizes a vent passage which allows atmospheric air to flow through the sparyer's lower body past a resilient, conically-shaped hollow valve into the container.

In U.S. Pat. No. 3,840,157, issued on Oct. 3, 1974 to J. F. Hellenkamp, a trigger operated sprayer is disclosed which differs from the sprayers of the aforementioned patents in that a plunger, or piston is mounted with its axis vertically aligned and movable off a sealing collar to permit venting of a container and is an example of a lever or trigger operated vent device, as is U.S. Pat. No. 3,749,290, issued on July 31, 1973 to L. A. Micalleff, which discloses a deformable diaphragm pump system wherein a venting surface is unseated to permit atmospheric pressure to be applied to the interior of the container. Other patented devices having venting means are U.S. Pat. No. 3,701,478, issued Oct. 31, 1972, U.S. Pat. No. 3,762,647, issued Oct. 2, 1973 and U.S. Pat. No. 3,770,206, issued Nov. 6, 1973 to T. Tada; U.S. Pat. No. 3,768,734, issued Oct. 30, 1974 to I. O. Anderson, Jr., et al.; and U.S. Pat. No. 3,820,721, issued on June 28, 1974 to J. F. Hellenkamp.

The present invention provides a simple, efficient, relatively inexpensive and easy to use venting system and includes an automatic drain back feature in a pleasantly appearing structure which operates during pumping and spraying and without the empolyment of additional parts or component mechanisms.

It is, therefore, an object of the present invention to provide a vent system for a manual, trigger operated sprayer which is simple in construction, efficient in operation, and is easily and economically manufactured.

It is another object of the present invention to provide a manually operated trigger sprayer which employs no separate or discrete mechanisms or other parts for venting the container on which it is mounted, nor additional components operatively associated therewith.

It is still another object of the present invention to provide a manually operated, trigger sprayer of the foregoing type wherein liquid which may leak by a seal element may be drained back into the container rather than being permitted to leak from the sprayer.

Other objects and advantages of the present application will be apparent from the detailed description and drawings which follow.

FIG. 1 is a sectional elevation of a preferred embodiment of the invention showing a trigger operated pump mechanism in its at rest or non-pumping condition;

FIG. 2 is a sectional elevation, similar to FIG. 1 of another embodiment of the invention.

With reference to FIG. 1, a trigger type, manually operated sprayer 10 comprising a housing or component retaining body 10-a having a cylindrical, hollow pump chamber or bore 11 closed at its upper end but in communication through its side wall by means of an exit or outlet passage 12 connected to a chamber 13 in a nozzle 14. Nozzle 14 has an exit orifice or "spray" nozzle opening 15. An inlet passage 16 provides communication between pump chamber or bore 11 and an inlet valve chamber 17 in an intake body portion 17-a. Chamber 17 contains, in sealing relation on a valve seat 19 therein, a ball check 18 in an inlet passage 20. A liquid pick-up, or dip tube 21 is fitted in air-tight relation and extends downwardly from body portion 17-a into a container 23 terminating near the bottom thereof (not shown). A container cap 22 is attached to body 10-a on body portion 17-a and is adapted to be clamped or screwed down onto the threaded neck portion of container 23 in liquid-tight relation therewith. A ring or lip seal 24 is formed on the bottom surface of body portion 17-a and mates with the top surface of container 23.

Slidably positioned for reciprocation in chamber or bore 11 is a plunger assembly 25 comprising a hollow piston 25-a and a carrier piece or holder 25-b. Holder 25-b has a recess 25-c on one end which engages an extension 27-a of an actuating trigger 27 mounted on body 10-a by means of a pivot or pin connector 29. Piston 25-a is fitted into a second recess in holder 25-b in the opposite end thereof, and in the embodiment shown, comprises a pair of spaced apart, annular circumferentially extending seals 30 and 31, the former preferably being a lip sealing angularly, rearwardly extending and sealingly contacting the wall of bore 11, whereas seal 31 preferably has a rounded, substantially circular appearance, also sealingly contacting the wall of bore 11. A compression spring 26 axially biases plunger assembly 25 in a direction away from or out of bore 11, spring 26 being mounted in bore 11 between the closed end thereof at one end and the hollow interior of piston 25-a, the parts described being arranged such that when at rest, as shown in the drawings, spring 26 may be under some slight compression. As is apparent from FIG. 1, when trigger 27 is actuated and pivoted about pin 29, plunger assembly 25 and piston 25-a reciprocate in bore 11 compressing spring 26 to initiate and maintain pumping operation of sprayer 10.

As mentioned above, in its preferred form piston 25-a is provided with spaced apart, peripheral lip seal 30 and annular, circular seal 31 which sealingly engage in sliding relation the inner wall of bore 11. In the at rest or non-pumping position as shown in FIG. 1, seals 30 and 31 are separated by a peripheral space or groove 32 and straddle the opening or entrance 33-a to a vent passage 33 formed in body 10-a in a bottom wall of chamber or bore 11. Passage 33 extends from space or groove 32 to one or more vertical passages 34 (one only shown in the Figures) formed in body portion 17-a and provides fluid communication to the interior of container 23 from space or groove 32 permitting, as will be seen, venting of container 23.

Once again referring to FIG. 1, it should be readily apparent that the present invention includes within its scope and is just as readily operated with a single seal on piston 25-a, which, preferably, would be forward lip seal 30. In this instance in the at rest position shown in FIG. 1 (and FIG. 2), piston 25 may be positioned in chamber 11 so that the seal 30 is in juxtaposition with opening or entrance 33-a of passage 33, by which is meant that seal 30 would normally, when in the at rest position of piston 25 (or 125 of FIG. 2), be in a position proximate to entrance 33-a on either side thereof in or on top of said entrance 33-a. It would, of course, be preferred in a single seal arrangement that seal 30 (or seal 130 of FIG. 2), be juxaposed with entrance 33-a on the trigger 27 side thereof to retain the "no leak" advantage previously referred to and described. However, operationally, the objective of venting would still be achieved with a single seal 30 (or 130) even if said seal is arranged in a normally at rest position in juxtaposition on the opposite side of opening 33-a or on top of said opening. In these latter arrangements, however, some leakage may be expected in some situations such as when sprayer 10 and container 23 is inverted or laid on its side. It is, of course, possible to modify sprayer 10 somewhat to avoid this eventuality in any of several well-known ways (not shown). For example, passage 33 may be formed as a capillary tube of fine diameter whereby liquid leakage which might occur will be insignificant, yet air passage will be uninhibited. Another means for obviating or mitigating against such possible leakage is the use of materials well-known to those skilled in the art in passage 33 which permit gas or air flow but inhibit or prevent liquid flow. Lastly mechanical devices such as check valves (not shown) may be employed in passage 33 or 34 to prevent liquid out flow while still permitting air flow in the opposite direction to vent container 23.

In operation of the FIG. 1 or preferred embodiment of the invention, container 23 is filled with liquid and sprayer 10 is attached by clamping or screwing down cap 22 onto the neck of container 23 with dip tube 21 extending below the liquid surface. A liquid-tight seal is obtained by seal ring 24 on the top surface of container 23 when cap 22 is screwed down or otherwise clamped on the neck thereof. Sprayer 10 is now ready for spraying liquid by grasping container 23 in the hand grip fashion, the fingers gripping trigger 27. Trigger 27 is squeezed forcing plunger assembly 25 and piston 25-a into bore 11 pressurizing the air therein and forcing ball 18 to close against seat 19. Air in chamber or bore 11 flows into exit or discharge conduit 12 and into chamber 13 of nozzle 14 forcing a slidable valve member 35 therein to move leftwardly. Fluid flows around valve member 35 through the radial passages formed between the vertical wall 35-a and ridges 35-b on the end of member 35 and is discharged in a spray through nozzle 14 orifice 15. When trigger 27 is released, piston 25-a and plunger 25 moves oppositely or leftwardly under the force of compressed spring 26, and trigger 27 returns to the "at rest" position shown. This action causes an expansion or increase in volume of chamber 11 and a slight vacuum developes which opens ball check 18 and forces valve member 35 in nozzle 14 to close against a seat 36 in chamber 13. Simultaneously liquid is drawn up into bore 11 through tube 21, chamber 17 and inlet passage 16. Seal 30 on piston 25-a prevents liquid leakage from chamber or bore 11, however should leakage occur liquid will flow back into container 23 through passages 33 and 34 from annular space 32, being prevented from flowing out of sprayer 10 by seal 31. Subsequent squeezing and releasing of trigger 27 repeats the above cycle except liquid is now being pumped and sprayed from container 23.

It is, however, necessary that atmospheric air be allowed to enter container 23 to make up for the volume of liquid drawn therefrom and equalize pressure therein. If venting is not allowed for, a vacuum will develope in container 23 and either liquid spray will cease or container 23 will tend to deform and/or collapse. The provision of vent passage 33 and passage 34 connected thereto in the wall of chamber or bore 11 and body portion 17-a respectively, permits venting communication between the interior of container 23 and the atmosphere to be established. When annular, spaced apart seals 30 and 31 are used on piston 25-a and straddle the entrance 33-a to vent 33, when trigger 27 is squeezed and piston 25-a moves into chamber 11, seal 31 will pass beyond opening or entrance 33-a to passage 33 and container 23 is vented to the atmosphere. It can be seen therefore, that the location of entrance 33-a to passage 33 between seals 30 and 31 in annular space 32, and closely adjacent to seal 31, permits venting of container 23 during the pumping or spraying stroke, yet in the non-pumping or "at rest" position, a positive closure for container 23 is simultaneously also provided.

Referring now to FIG. 2, an additional embodiment is disclosed wherein a one-piece piston and plunger device 125 is shown. Piston or plunger 125 is preferably a single molded piece including the spaced apart, annular, circumferentially extending seals or sealing surfaces 130 and 131 separated by the peripheral, or annular recess 132, and, as shown in FIG. 2, is in the at rest position. In this position, seals 130 and 131 straddle opening or entrance 33-a vent passage 33 as in the preferred, FIG. 1 embodiment. In all other respects as to construction and operation, the FIG. 2 embodiment is identical with the FIG. 1 invention. In addition, while not shown herein, it is evident that seal 130 could also be formed, as by molding and the like, as a lip seal for enhanced sealing quality usually characteristic of this type seal and, due to less friction between seal and wall would provide faster return of the pump and trigger to the at rest position by compressed spring 26.

It should also be understood that a single seal element device, similar to that previously disclosed is applicable to this embodiment and such is fully contemplated. Also piston or plunger 125 can be molded with suitable annular grooves (not shown) in which O-ring type seals or the like, can be installed in place of the shown seal elements 130 and 131 with comparable beneficial results. In addition, the sealing elements associated with the piston can also be located in bore 11 remaining stationary relative to piston 25 when the latter is reciprocated. In short, any number of methods can be employed to provide the necessary sealing between piston and bore in chamber 11 and will occur to the skilled artisan. Similarly, leakage if apparent, can be dealt with in accordance with the known methods, previously described.

It is expected that the invention hereinabove described will be constructed of thermoplastic materials by any of the usual and well-known processes, for example, blow molding, injection molding, casting or the like, depending on materials used and sprayer qualities desired. Examples of suitable materials useful in carrying out the invention include any of the well-known plastics such as polystyrene, polyvinylchloride, polyurethane, the polyolefins, polyamide, polyacetate, polycarbonate, polyester and the many possible mixtures or blends thereof. A preferred material is the polyolefin, polypropylene, which has many desirable qualities including being resilient and is thus particularly useful for sealing elements or devices and for the pistons 25-a and 125. Other suitable materials include natural rubber, synthetic rubber, acrylonitrilebutadiene styrene (ABS) and mixtures of these and other materials. Each material will be selected in accordance with good engineering practice to maximize quality and minimize cost and expense.