Harvesters – Motorized harvester – Having motor on ground-supported carrier
Reexamination Certificate
2000-09-01
2003-03-11
Will, Thomas B. (Department: 3671)
Harvesters
Motorized harvester
Having motor on ground-supported carrier
C056S015200, C056SDIG002
Reexamination Certificate
active
06530200
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a lawn mower having a mower unit vertically movable to adjust a grass cutting height.
2. Description of the Related Art
In a typical conventional mechanism for raising and lowering a mower unit, the mower unit is attached to a vehicle body through a raising and lowering link mechanism which is vertically movable by a control lever (see U.S. Pat. Nos. 5,678,648 and 5,410,923).
However, where the above construction is employed, the control lever and other levers are disposed laterally of a driver's seat to be obstructive to the driver boarding or alighting from a driving platform. In addition, a great operating force is required to raise the mower unit with the control lever. To reduce this burden, gas springs or a gear mechanism must be employed for balance, which tends to render the mechanism considerably complicated.
SUMMARY OF THE INVENTION
The object of this invention is to provide a lawn mower having a mower unit raising and lowering function, in which a control lever for raising and lowering a mower unit is not obstructive to the driver boarding or alighting from the mower, a reduced burden falls on the driver in raising and lowering the mower unit, and a good vehicle body balance is maintained.
The above object is fulfilled, according to this invention, by a lawn mower comprising a vehicle body, front wheels disposed in front positions of the vehicle body, rear wheels disposed in rear positions of the vehicle body, a mower unit suspended from the vehicle body between the front wheels and the rear wheels, a driver's seat disposed on the vehicle body above the mower unit, and an actuator disposed above the mower unit and below the driver's seat for raising and lowering the mower unit.
In this construction, an actuator is employed to the burden falling on the driver in raising and lowering the mower unit. Further, this lift actuator disposed between the driver's seat and the mower unit is not obstructive to the driver boarding or alighting from the mower. This mower has an excellent body balance since the mower unit is disposed between the front and rear wheels, and the actuator is disposed above the mower unit. The actuator disposed between the front and rear wheels can receive a reaction from an upward movement of the mower unit in a stable way.
In a different lawn mower constructed to fulfill the above object, a hydraulic lift cylinder is used as the lift actuator, with a hydraulic pump disposed below the driver's seat and adjacent the hydraulic cylinder for supplying a hydraulic pressure to the hydraulic cylinder, and an engine disposed rearwardly of the driver's seat for driving the hydraulic pump.
This construction provides additional advantages of shortening the length of piping from the hydraulic cylinder to the hydraulic pump, and smoothening drive transmission from the engine or gearbox to the hydraulic pump.
In a preferred embodiment of this invention, the vehicle body includes a pair of right and left plate frames extending in a traveling direction, the actuator being disposed substantially between the plate frames. This construction allows the actuator to receive the reaction with increased stability.
As a preferred embodiment, the actuator may be operable by a control switch disposed on a steeling lever. It is then possible to dispense with a control post or lever dedicated to the control of the lift actuator.
Other features and advantages of this invention will be apparent from the following description of the embodiment to be taken with reference to the drawings.
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patent: 4998948 (1991-03-01), Osterling
patent: 5381648 (1995-01-01), Seegert et al.
patent: 5410923 (1995-05-01), Yamashita et al.
patent: 5475971 (1995-12-01), Good et al.
patent: 5483789 (1996-01-01), Gummerson
patent: 5678648 (1997-10-01), Imanishi et al.
patent: 5913802 (1999-06-01), Mullet et al.
patent: 6032441 (2000-03-01), Gust et al.
patent: 6076341 (2000-06-01), Gummerson
patent: 6122903 (2000-09-01), Hayashi et al.
patent: 6293077 (2001-09-01), Plas et al.
Komorida Takeshi
Minoura Akira
Samejima Kazuo
Kubota Corporation
Petravick Meredith C.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
Will Thomas B.
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