Fluid sprinkling – spraying – and diffusing – Fountains or drinking tubes and straws – Ornamental
Reexamination Certificate
1998-01-05
2001-03-27
Morris, Lesley D. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Fountains or drinking tubes and straws
Ornamental
C417S411000, C415S169100
Reexamination Certificate
active
06206298
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a miniature DC powered water pump and to waterfall or water fountain displays employing such a pump.
BACKGROUND OF THE INVENTION
A waterfall display typically employs a submersible water pump to circulate water from a lower reservoir to an elevated surface from which the water cascades back toward the lower reservoir, thereby creating a simulated waterfall. Examples of such waterfall displays are disclosed in U.S. Pat. Nos. 3,901,439, 5,326,032 and 5,571,409. Such a waterfall display tends to be bulky and heavy because the pump is typically a submersible alternate-current (AC) powered pump that is large and unwieldy and requires a large reservoir for submersion therein. Submersible AC powered pumps are typically bulky and costly to manufacture because, due to their high operating voltage, they must meet stringent electrical shielding and/or insulation requirements to protect users and the pumps in an aqueous operating environment. The associated AC power cord also detracts from the aesthetics of the display as it is difficult to hide and route. Furthermore, the power cord, because of its limited length, restricts where the display may be located. As a result, the display can often not be placed at a desired location.
Accordingly, there is a need for small, low-cost battery or direct-current (DC) powered water pumps which have none of the aforementioned disadvantages. However, such DC powered water pumps must be energy efficient so as not to require users to frequently replace or recharge the batteries powering the motors. One way to increase the efficiency of a water pump is to reduce friction encountered by the rotating shaft of the motor. Because the motor must also be in a water tight chamber, a seal or gasket must be used to isolate the motor from the water. Such a gasket is mounted tightly about the shaft to isolate the motor from the aqueous environment in which the pump operates. The gasket must be dimensioned to apply sufficient sealing force against the motor shaft so as to prevent water from passing between the shaft and the gasket to reach the motor. However, such a tightly fitting gasket is a source of a considerable frictional load on the motor.
U.S. Pat. No. 4,021,150 discloses a battery powered water pump with a fluid flow directing device for directing fluid admitted through an inlet port to flow away from the motor shaft bearing toward the impeller of the pump. The fluid flow directing device consists of a conical section or a propeller mounted onto the motor shaft. However, in this device, all of the water being pumped flows past the motor shaft from the motor housing, thereby increasing the likelihood that water will leak into the motor housing to damage the motor.
SUMMARY OF THE INVENTION
The present invention is directed to a cascade waterfall or water fountain display with a compact, energy-efficient, low cost DC powered water pump. An electronic controller controls the operation of the water pump and is also used to generate visual and sound effects. Multiple water pumps may be used to vary the intensity of the simulated waterfall or to create several distinct water flowing paths.
The waterworks display includes a cascade structure having a top reservoir, and a base reservoir disposed proximate the base for containing water. A water pump is used to pump the water to the top of the cascade waterworks structure from which the water cascades by gravity to the base reservoir.
The water pump is comprised of a DC motor with a motor shaft, a motor housing in which the motor is mounted, and a gasket used to loosely seal the motor within the motor housing. The gasket has an aperture therein through which the motor's shaft passes. The gasket's aperture is sized so that the shaft of the motor passes therethrough with little, if any contact. An impeller is mounted to the motor's shaft for rotation within a pumping chamber. The pumping chamber has a plurality of holes through which water enters, and an outlet through which water is pumped by the impeller to the top of the waterworks structure. The pumping chamber is loosely fit about the shaft of the motor and allows some water to pass out of the pumping chamber around the motor's shaft to a pressure-relief chamber. The pressure relief chamber, which is located between the pumping chamber and the motor, has a water outlet port through which any water that has entered the pressure-relief chamber exits the water pump. As a result, pressurized water is less likely to enter the sealed cavity of motor housing through the aperture of the gasket, and thus the likelihood is reduced that water will come into contact with the motor to damage it. Consequently, the seal between the aperture in the gasket need not tightly fit the shaft of the motor, but may instead be a loose fit, thereby reducing friction and resistance to the operation of the motor. In addition, by not providing a water-tight seal between pumping chamber and the shaft of the motor, friction opposing rotation of the shaft is reduced.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for the purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.
REFERENCES:
patent: 3901439 (1975-08-01), Willis
patent: 4021150 (1977-05-01), Mabuchi
patent: 4352149 (1982-09-01), Stetler
patent: 5167368 (1992-12-01), Nash
patent: 5288018 (1994-02-01), Chikazumi
patent: 5326032 (1994-07-01), Quillin
patent: 5480590 (1996-01-01), Neshat et al.
patent: 5571409 (1996-11-01), Scarborough
Cohen & Pontani, Lieberman & Pavane
Morris Lesley D.
T.L. Products Promoting Co., Ltd.
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