Motor vehicles – Steered by walking attendant
Reexamination Certificate
2002-05-01
2004-06-08
Morris, Lesley D. (Department: 3618)
Motor vehicles
Steered by walking attendant
C180S065100, C280S047260, C280S653000
Reexamination Certificate
active
06745859
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a powered wheel assembly for use in connection with a wheelbarrow. In particular, the invention relates to a powered wheel assembly capable of retrofit to an existing wheelbarrow that permits an operator to selectively operate the wheelbarrow in a powered and non-powered mode of transport.
BACKGROUND OF THE INVENTION
Operators have used wheelbarrows since at least as early as 230 A.D. for transporting articles ranging from dirt to various building materials. More recently, operators have secured engines to wheelbarrows to assist in the transport of heavy materials. Several existing motorized wheelbarrows provide operators with the ability to select varying gears and speeds. These wheelbarrows incorporate complicated clutch systems and gear drives that require frequent maintenance. Furthermore existing motorized wheelbarrows are typically sold as a complete unit that includes a frame, pan, handles, engine, and wheel assembly. Thus, a consumer must purchase an additional wheelbarrow when seeking a motorized alternative. Accordingly, the consumer faces the maintenance costs and storage problems associated with two wheelbarrows, one for powered transport and another for non-powered or manual transport. Moreover, the cost of the complete unit offered for sale is oftentimes prohibitively expensive. Thus, there is a need for a relatively inexpensive motorized wheel assembly that is capable of retrofit to an existing wheelbarrow.
Known motorized wheelbarrows that include an engine and drive train often provide a neutral gearing position wherein the drive train is not engaged with the wheel assembly (i.e., axel, drive sprocket, and wheel). The operator may use the neutral position while manually pushing the wheelbarrow when, for example, the engine runs out of gas or when transporting light loads. Nevertheless, the wheel assembly of the known devices remains operatively connected to the drive train and creates frictional forces that the operator must overcome when manually pushing the wheelbarrow. Accordingly, there is also a need for a motorized wheelbarrow that permits the operator to select between powered assistance for the transport of heavy materials (e.g., rocks) and non-powered assistance for the transport of lightweight articles (e.g., gardening tools and clippings). Specifically there is a need for a motorized wheelbarrow that includes a non-powered mode of transport wherein the wheel is free to rotate independent of the drive train and free from the frictional forces associated therewith.
Variations of motorized wheelbarrows exist to assist the consumer with routine tasks. For example, existing motorized wheelbarrows having a pivotable pan permit operators to easily unload (i.e., dump) the materials under transport. Nevertheless, the pivoting mechanism tends to fail and requires additional maintenance and expense.
U.S. Pat. No. 4,589,508 to Hoover et al. describes a motorized wheelbarrow capable of powered movement in a forward and reverse direction. More specifically, Hoover discloses a friction drive mechanism having a moveable friction wheel mounted on a swing arm and operated by a friction lever to promote forward and rearward travel. Hoover further discloses a pivotable bed. Nevertheless, Hoover fails to provide an assembly that can be easily retrofit on the type of wheelbarrow most commonly used by consumers. For example, Hoover requires structural modification of the wheelbarrow frame to include different kinds of vertical and horizontal supports for securing pans of varying shape to the frame. Further, Hoover fails to provide an apparatus that promotes ease of use. For example, Hoover employs a friction drive lever and throttle lever mounted on both handles of the wheelbarrow, thus requiring an operator to manipulate both handles during operation. Further, Hoover incorporates a hinge and lock mechanism for pivoting the bed. This type of mechanism promotes structural fatigue of the frame at the pivot points. Although the drive train of Hoover provides a neutral selection for manual movement of the wheelbarrow, the wheelbarrow encounters resistance from the drive train because the transmission remains operatively engaged with the wheel. Accordingly, friction caused by the drive train prevents free rotation of the wheel. In other words, the operator must push the wheelbarrow with enough force to overcome resistance inherent with the drive train. Accordingly, the structural modifications necessary for interchanging beds, the difficulty of use in operation, and the lack of a freely rotating wheel render the Hoover apparatus impractical for use during ordinary yard work. In addition, the frictional forces inherent with drive train-even while in neutral-require the user to exert excess force to move the wheelbarrow when, for example, it runs out of gas.
In comparison, the present invention does not require a friction drive lever for gradual drive engagement. Nor does the present invention require structural modification for retrofit on an existing wheelbarrow. Moreover, the freely rotating wheel of the present invention in the non-powered mode requires less force to move the wheelbarrow when pushed manually. The ease with which the present invention can be retrofit provides an economically viable option for consumers requiring a motorized wheelbarrow. Simply stated, the present invention is easier to install, maintain, and operate (i.e., no structural modification, minimal downtime to retrofit, and maintainability of the drive train).
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a powered wheel assembly that is capable of easy retrofit to an existing wheelbarrow.
Yet another object of the invention is the provision of a powered wheel assembly that permits the operator to select between powered assistance for the transport of heavy materials and manual operation for the transport of lightweight articles.
A further object of the invention is the provision of a motorized wheelbarrow that promotes a freely rotating wheel during manual operation of the wheelbarrow.
The invention meets these objectives with a powered wheel assembly that is capable of retrofit on an existing wheelbarrow and that permits an operator to selectively operate the wheelbarrow in a powered and non-powered mode of transport. In particular, the invention is a powered wheel assembly having a frame assembly that is attachable to an existing wheelbarrow, a wheel assembly secured to the frame, and a drive assembly that can selectively operate the wheel assembly to move the wheelbarrow under power.
REFERENCES:
patent: 3791470 (1974-02-01), Baddorf et al.
patent: 4589508 (1986-05-01), Hoover et al.
patent: 5211254 (1993-05-01), Harris, III et al.
patent: 5305843 (1994-04-01), Armstrong
patent: 5350030 (1994-09-01), Mawhinney et al.
patent: D357101 (1995-04-01), Uyehara et al.
patent: 5465801 (1995-11-01), Hoover
patent: 5489000 (1996-02-01), Hillbohm
patent: 5878827 (1999-03-01), Fox
patent: 6173799 (2001-01-01), Miyazaki et al.
Simons Beverly Ann
Simons Roger Larry
Lum L.
Morris Lesley D.
Summa & Allan P.A.
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