Fluid reaction surfaces (i.e. – impellers) – Support mounting – carrier or fairing structure
Reexamination Certificate
1999-02-19
2001-05-01
Look, Edward K. (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Support mounting, carrier or fairing structure
C416S062000, C416S235000, C411S188000, C411S429000, C411S908000
Reexamination Certificate
active
06224340
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an improved system for securing a fan to a drive shaft. In particular, the system is useful for securing fans in blower/vacuum systems used for vacuuming or blowing debris, such as leaves and grass clippings, from a lawn or other ground surface.
2. Background of Related Art
Although applicable in a variety of environments, the securing system of the invention is especially useful for securing a fan to an armature shaft in a blower or blower/vacuum. Various systems are known in the art for securing a fan to a drive shaft within the blower/vacuum environment. In such environments, a fan is mounted to a drive shaft for rotation. In the vacuum configuration, spaced fan blades allow a range of debris to pass through them to an outlet and generally to a collection apparatus. In the blower configuration, a discharge tube may be connected to the outlet to discharge exhaust air.
A known system is shown in
FIG. 2. A
centrally aligned mounting boss includes interior bores and which receive the end of a drive shaft to form an interference fit. An additional known configuration involves providing a standard nut at the end of the armature shaft. Difficulties encountered with these and other known configurations include the awkward shape of the fan creating balancing difficulties within the mold, slipping of the armature within the interior fan bores, and loosening of the standard nut. Additionally, the use of a standard nut requires relatively costly insulation between the armature and the armature shaft in order to double insulate the touchable parts.
Plastic parts tend to creep over time and as a result of moisture and temperature variations. Accordingly, prior art systems, which involve tightening an ordinary plastic nut are often inadequate because the nut tends to loosen.
SUMMARY OF THE INVENTION
Objects of the invention include the provision of a fan securing system that provides a securely mounted fan, an insulating barrier that prevents the operator from touching the armature shaft, and a fan shape that balances well within a mold.
These and other objects are achieved by providing a fan securing system for securing a fan onto an armature shaft. The securing system comprises a nut having a central aperture through a first surface. The first surface includes a series of ramps spaced around the central aperture. Internally molded threads within the central aperture engage the armature shaft. A first fan surface portion comprises a central aperture through which the armature shaft passes and a series of interruptions configured to interlock with the series of ramps on the nut. The interruptions may comprise recesses or mating ramps.
The objects are further achieved by providing a blower/vacuum for selective operation in blower mode and suction mode, the blower/vacuum comprising an armature shaft and a fan mounted on the armature shaft through a central aperture. The fan comprises a first fan surface portion having a series of interruptions. A nut having a central aperture through a first surface is provided. The aperture has internally molded threads that engage the armature shaft. A series of ramps is spaced around the central aperture. The ramps are configured to interlock with interruptions on the first fan surface portion.
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Black & Decker Inc.
Gambhir Ajay
Look Edward K.
McDowell Liam
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