Patent Application
20070114247
The present invention generally relates to pump mechanisms. More particularly, the present invention relates to pump mechanisms that are employed in dispensers, most often wall-mounted dispensers for soap and other hand-treatment products.
Wall-mounted dispensers for fluid or flowable products are well known in the art. These generally consist of a wall-mounted cabinet with a chamber for receipt of refills containing the flowable product. A dispenser base is mounted on a wall or counter top and a cover is usually hinged to the dispenser base to provide access to the interior. The dispenser base includes various types of receptacles or shelves designed to support and position a cartridge, bag or box that contains the product to be dispensed. These cartridges, bags, boxes, etc., are replaceable so that the dispenser can be refilled when the product supply is exhausted.
These cartridges or refills take various shapes and forms in the prior art. Perhaps the most common currently used are combination bag and pump arrangements that include a collapsible bag containing the flowable product, and a pump mechanism affixed to the bag and communicating with the flowable product. The bag may be retained in a box, as known. The bag or bag-and-box, as the case may be, is simply placed inside the dispenser when needed, and the flowable product is dispensed from the bag, through the pump, generally by utilization of a hand-operated lever that appropriately contacts and compresses the necessary pump mechanisms and forces the flowable material out of a nozzle of the pump.
Of particular interest in this invention are dome pumps. In these pumps, an inlet and an outlet, both with appropriate valve mechanisms, communicate with a pump body, and a flexible dome extends over the body to retain the flowable product. When pressure is applied to the flexible dome causing the flexible dome to collapse, the inlet valve is closed and the outlet valve is opened, allowing product to be forced out of the outlet. As pressure is removed from the flexible dome, the outlet valve closes and the inlet valve opens to allow additional product to be drawn from the product source into the interior volume of the dome. Examples of dome pumps can be found in U.S. Pat. Nos. 3,486,663; 3,820,689; 3,987,938; 4,168,020; 5,207,355; 5,505,341; and 6,216,916. The prior art contains many other variations on this general theme.
The valves in the prior art dome pumps are often spring-biased ball valves, and it will be appreciated that such valve constructs involve multiple parts and manufacturing steps. Thus, some in the art have begun to construct valves from the dome itself. For example, the dome-type pump in U.S. Pat. Nos. 3,820,689 and 5,505,341 extend the dome to create both an inlet sealing flap that seals off the inlet port communicating with the interior of the dome and an outlet sealing flap that seals off the outlet port. As these prior art references show, there is need in the art for dome-type pump constructs that improve upon and reduce the complexity of the prior art designs by beneficially employing the dome portion (or compressible portion) as a valve.
Notably, the flexible dome portion of the dome pumps are often constructed from silicone. This is because silicone rubber is appropriately flexible and resilient, having a tendency to return to a molded shape, and tends not to swell or degrade in contact with various fluids, thus retaining its flexibility. Silicone rubber is also readily made translucent, which has been found to be beneficial in dispenser arts employing dome pumps, as in U.S. Pat. No. 6,216,916. However, the silicone is unduly expensive, and a need exists for pumps that need not employ silicone.
Thus, there exists a need in the art for a pump that employs less expensive materials than the silicone typically employed; that is easy to manufacture, and reduces the necessary number of parts employed by employing the compressible portion thereof as a valve.
This invention generally provides what is termed herein a “bellows pump,” because the main element that is manipulated to operate the pump (the compressible portion) includes structure similar to that of a camera bellows. The bellows pump includes a pump body having a base wall defined by a base wall perimeter. An inlet aperture is provided in the base wall, offset from the base wall perimeter, and an outlet aperture is also provided in the base wall, offset from the base wall perimeter. A bellows member is secured to the pump body and includes an open end defined by a sealing flange that is sealed to the base wall, with the inlet aperture and the outlet aperture being positioned within the open end. The bellows member further includes a sealing web extending inwardly from all points of the sealing flange to a first hinge, and a dosing web extending outwardly from the first hinge at one end thereof to a bellows cap at the other end thereof, the bellows cap creating a closed end opposite the open end. The sealing web, the dosing web and the bellows cap define a dose volume between the base wall of the pump body and the bellows cap, wherein pressing on the bellows cap toward the base wall collapses the bellows member such that the sealing web covers the inlet aperture but does not cover the outlet aperture, thereby expelling at least a portion of the contents of the dose volume out the outlet aperture.
In particularly preferred embodiments, the bellows member is formed of material other than silicone. Suitable materials have been found to be thermoplastic rubbers, ethylene-propylene-diene monomers (EPDMs), polyisoprenes, butyl rubbers, low density polyethylenes, and thermoplastic polyesters. A particular useful thermoplastic polyester is Hytrel™ (DuPont).
In particularly preferred embodiments, the pump body includes an outlet fitment and an inlet fitment and a spout fits over the outlet fitment and carries a valve that is retained by a valve retaining ring. A bellows retaining ring engages the bellows member and the pump body to seal the sealing flange to the base wall of the pump body. The pump body is formed in one piece, as is the bellows member, and the pump body, the bellows member, the bellows retaining ring, the spout, the valve and the valve retaining ring create the complete bellows pump. The bellows member may even be formed with the bellows retaining ring as one piece.
For a complete understanding of the objects, techniques and structure of the invention, reference should be made to the following detailed description and accompanying drawings wherein:
With reference to
It will be appreciated that this specific construction providing inlet fitment 22 and outlet fitment 26, at substantially right angles, as shown in the figures, readily allows for the substitution of bellows pump 10 into combination bag and pump arrangements and dispensers employing the same. By way of representative example, a bellows pump in accordance with this invention may be employed in bag and pump arrangements and dispensers such as those shown in U.S. Pat. No. 6,216,916. Particularly, inlet fitment 22 may communicate with a bag that retains flowable product, and outlet fitment 26 may communicate with portions of dispensers made to employ such combination bag and pump arrangements. Flange 27 (
Bellows member 30 fits over base wall 14 and serves as the actual pump mechanism. That is, the compression and expansion of bellows member 30 results in the dispensing of a dose of product and the loading of a new dose into the internal volume of bellows member 30. As seen in
Referring now to
Sealing web 34 extends inwardly from all points of sealing flange 40 to first hinge 44. Dosing web 36 extends outwardly from first hinge 44 at a first end 45 thereof and joins with bellows cap 32 at a second end 46 to create a closed end opposite open end 38. Thus, when bellows member 30 is sealed to base wall 14 at sealing flange 40, bellows cap 32, sealing web 34, dosing web 36 and base wall 14 define a dose volume V. Bellows member 30 is preferably formed from a single, blow molded or injection molded piece, and, as mentioned, might be molded as one piece with bellows retaining ring 42.
In
With reference to
Although it will be appreciated that appropriate valving could be employed in outlet fitment 26 to permit for only the dispensing of product P from dose volume V and prohibit the pulling of product P through outlet fitment 26 into dose volume V, the preferred embodiment of the present invention employs valve mechanisms in a separate spout element, namely spout 50. As seen in
Pump body 12, including inlet fitment 22 and outlet fitment 26, is preferably formed from lightweight, rigid materials. Many plastics are suitable, such as polypropylene, polyethylene, acetal or acrylonitrile butadiene styrene (ABS). Spout 50 is also preferably formed from such materials.
Bellows member 30 is preferably formed from resilient, flexible materials, particularly those capable of returning the bellows member from its compressed state to its rest state thousands of times, without seriously compromising the integrity of the bellows member. Preferably, the entire bellows member 30 is formed from the same material to simplify manufacturing, but it is contemplated that certain portions might be formed from one material while other portions are formed from different materials. Silicone rubber may be employed for bellows member 30, but is preferably avoided due to costs. Broadly, elastomeric rubbers are preferred.
In some embodiments, bellows member 30 is formed from materials selected from the group consisting of polyvinly chloride (PVC), thermoplastic rubbers, EPDMs, polyisoprenes, butyl rubbers, and low density polyethylenes (LDPEs) and thermoplastic polyesters. A particular useful thermoplastic polyester is Hytrel™ (DuPont).
When sealing flange 40 is to be secured by bellows retaining ring 42, sealing flange 40 is preferably made of readily compressible elastomeric material. The EPDM, polyisoprene and butyl rubber materials would be suitable. Trefsin™ (a thermoplastic rubber from Advanced Elastomer Systems, grade number 3271-65W308) is particularly useful because it is resistant to soaps.
If sealing flange 40 is ultrasonically welded to base wall 14, low density polyethylene could be employed for sealing flange 40 and the remainder of bellows member 30. Engage™, a LDPE from DuPont Dow Elastomers, ethylene-octene copolymer, is suitable, and is transparent, flexible and durable.
Having illustrated and described the principles of this invention in a preferred embodiment thereof, it should be readily apparent to those skilled in the art that the invention can be modified in arrangement and detail without departing from such principles. Accordingly, for an appreciation of the true scope of the invention, reference should be made to the accompanying claims.
