Baths – closets – sinks – and spittoons – Obstruction remover – Force cup
Reexamination Certificate
1996-07-10
2002-04-23
Fetsuga, Robert M. (Department: 3751)
Baths, closets, sinks, and spittoons
Obstruction remover
Force cup
Reexamination Certificate
active
06374427
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to drain-clearing devices and more particularly to improved drain plungers.
2. Prior Art
Various types of devices have been used in the past to clear water and sewage drains of clogs. One well-known type utilizes a spirally coiled “snake” which is fed down the drain hole and rotated to force obstructions from the drain. Such devices have been known to damage drain pipes and are not used unless severe clogging occurs, and then only usually by professionals.
Another type of drain-clearing device comprises an inverted, relatively stiff, thick rubber cup to the top of which is connected a wood or metal vertical handle. Although such a device is effective in many instances to clear certain types of drains, it has a serious drawback, in that the cup is initially very difficult to compress or collapse and then suddenly rapidly compresses, causing a very forceful surge in the drain, sometimes forcing drain pipe connections apart and causing drain pipe leaks. Moreover, the cup is not well adapted for use with various types of drains.
More exotically shaped drain plungers are exemplified by U.S. Pat. Nos. 2,188,960 and 2,844,826. In most cases, commercially available drain plungers and similar devices have poor sealing power with the surface surrounding the drain hole and therefore such plungers are unable to provide the necessary controlled compressive and suction force needed to clear clogged drains.
A toilet drain plunger of an improved type is set forth in U.S. Pat. No. 4,745,641 to Tash, inventor of the present claimed plunger. The reference Tash plunger incorporates a durable bottom ring seal, which is relatively inflexible, and is designed to engage the bottom surface defining the bottom drain hole in a toilet bowl, the lower end of the plunger fitting into that hole, while an upper annular shoulder of the plunger bottom portion engages the upper surface defining that drain hole. Drain unclogging is effected by both the compression and suction portions of the plunger compression-suction cycle. Although that plunger is desirably designed for unclogging toilet drains, it is less efficient on other types of drains, including sink drains and the like surrounded by flat surfaces.
SUMMARY OF THE INVENTION
The improved drain plunger of the present invention satisfies all the foregoing needs. Thus, a drain plunger is provided which is compact, simple, inexpensive, easy to use and highly efficient. It seals readily to a variety of surfaces defining drain holes of differing sizes and shapes and imparts a powerful but controlled suction to the drains after readily sealing the drain holes so as to enable rapid clearance of drains of obstructions. Compression of the plunger is easily carried out without damaging the drain plumbing and with relatively little effort.
The plunger is substantially as set forth in the ABSTRACT OF THE DISCLOSURE. Thus, an improved drain plunger is provided which preferably is formed in a single molding operation of a mixture of plastics having differing degrees of resilience, flexibility, elastic memory and rigidity. For example, the plunger can comprise a generally upstanding elongated stiff handle of high density polyethylene or other plastic and a lower bellows portion with integral bottom sealing rim, the bellows portion comprising a mixture of low density polyethylene plastic and ethylene-vinyl acetate copolymer, wherein the mixture is varied progressively to import an improved compressibility and drain sealability to the bellows of the plunger.
The bellows of the plunger is generally frusto-conical and comprises a narrow diameter top sealed to the lower end of the handle and annular sidewalls depending downwardly and outwardly to define a central space and the bottom sealing rim which has a diameter substantially larger than that of the top. The sidewalls comprise a plurality of generally horizontal, interconnected vertically stacked pleats which easily collapse on each other during compression of the bellows.
The lower rim of the plunger is of special configuration and integral with the lowermost pleat of the sidewalls of the bellows. Thus, the rim comprises a downwardly and inwardly directed wall, the inner margin of which defines the central opening in the plunger bottom. The inner margin of the rim is forced sightly inwardly and upwardly during compression of the bellows against a drain hole-bearing surface to create a good seal. When the handle of the plunger is pulled up after compression of the bellows against the drain hole surface, the inner margin of the sealing rim moves downwardly and slightly outwardly to increase very strongly its engagement with such surface, greatly improving the sealing effect of the rim and thus greatly improving the suction effect exerted by the plunger for more rapid and efficient drain clearance. This is a vast improvement over prior art plungers utilizing lower rims which are relatively inflexible and/or which largely depend on a compressive action to effect clogging of drains.
The present device substantially differs in shape, sealing mode and operation from the plunger of the Tash patent described above. Thus, the present claimed plunger employs a bellows which is frusto-conical with a narrow diameter top and wide diameter bottom so as to fit a wide range of configurations and sizes of drain holes. Moreover, the bellows, including the lower rim, is formed of material which, during such formation, is varied in content in order to progressively increase the flexibility of the bellows from its top to bottom for easier operation of the bellows. In addition, the lower rim of the bellows curves inwardly and upwardly and changes shape and direction during compression of the bellows and when decompression of the bellows is begun to increase suction on the drain hole. This results in improved suction and more rapid, non-damaging clearance of drain clogs. The main declogging occurs during the strong suction provided by the plunger, rather than depending on alternating compression and suction for results.
REFERENCES:
patent: 1152981 (1915-09-01), Schacht
patent: 1154055 (1915-09-01), Reeves
patent: 2846698 (1958-08-01), Tomlinson
patent: 4745641 (1988-05-01), Tash
Fetsuga Robert M.
Lyon & Harr
Watson Mark A.
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