Harvesters – Motorized harvester – Having motor on ground-supported carrier
Reexamination Certificate
2000-06-19
2002-12-10
Pezzuto, Robert E. (Department: 3671)
Harvesters
Motorized harvester
Having motor on ground-supported carrier
C056S010800, C056S014700
Reexamination Certificate
active
06490849
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to lawn mowers, and the more particularly to self-propelled, walk-behind commercial type lawn mowers having a platform attached to the rear of the mower for accommodating a standing operator.
Most current lawn mowers designed for commercial use are either dedicated walk-behind lawn mowers or conventional riding lawn mowers. Commercial type riding lawn mowers are generally quite large, heavy and difficult to maneuver around obstacles, such as trees and shrubs and the like. An example of such a riding lawn mower is shown in U.S. Pat. No. 4,809,796 to Yamaoka et al. Riding lawn mowers are also quite expensive to purchase and maintain. The substantial cost of purchasing and maintaining riding mowers has led lawn mower service companies to rely more heavily on the use of lower cost, mid-size, walk-behind rotary mowers.
The walk-behind mowers are generally smaller, more maneuverable, and less expensive than riding mowers. Being self-powered, these mowers are capable of cutting large areas of grass. The walk-behind mowers are also relatively simple to operate, and inexpensive to purchase and maintain compared to riding lawn mowers. In addition, these mowers are generally safer and more useful in mowing steep hills. Furthermore, they are small enough to be easily stored and transported by commercial lawn mower service companies. One example of a self-powered, walk-behind mower is shown in U.S. Pat. No. 4,920,733 to Berrios.
However, a major disadvantage of walk-behind mowers is that they require the operator to walk the entire area of grass being cut. This may account for up to eight or more hours walking per day, which can be a very exhausting experience over the period of a full work day, even if the mower is self-powered.
Because walk-behind mowers are still fairly heavy and cumbersome pieces of equipment to maneuver, various types of attachments have been designed to reduce the amount of walking required by operators. These attachments, commonly known as sulkies, allow an operator to ride behind the mower in a reasonably comfortable standing or seated position during prolonged operation of the mower. A sulky is typically a wheeled attachment having a standing platform or a seat that is removably attached to the back end of the mower. Patents showing a sulky attached to a self-propelled, walk-behind lawn mower include U.S. Pat. Nos. 5,004,251 to Velke et al; 5,388,850 to Simone; and 5,413,364 to Hafendorfer. In using a stand-up sulky, the operator stands on a platform, while in using a sit-down sulky, the operator sits in an upright position on a seat that is customarily mounted at the rear of the sulky, with the operator's feet resting on a platform.
The use of sulky attachments for walk-behind mowers has not been entirely satisfactory because they often restrict maneuverability of the mower. The sulky adds considerable length to the mower, making it difficult to maneuver around obstacles, such as trees and shrubs and the like. In addition, the sulky does not permit easy reverse movement of the mower because it pivots around the attachment point on the mower, and can easily jack-knife.
There have also been a number attempts to design a lawn mower having a standing platform attached to the rear of the mower for supporting a standing operator. Examples of patents disclosing these types of mowers include U.S. Pat. Nos. 4,878,339 to Marier et al.; 5,507,138 to Wright, et al, 5,653,466 to Berrios; 5,809,756 to Scag et al.; and 6,059,055 to Velke, et al. All of these patents show a standing platform attached to the rear of the mower behind or at the rear wheel axle. The position of the platform on the mower as shown in the prior art creates a generally unstable and unsafe operating condition for a standing operator. An operator standing on the platform moves the center of gravity toward the rear of the mower making it very unstable to operate especially on hills.
Most prior art lawn mowers having a platform for supporting standing operators have the platform attached to the mower either behind the rear wheel axle or substantially on the rear wheel axle. This location has many inherent problems. The center of gravity of the mower with an operator standing on the platform is typically only a few inches in front of the rear wheels and about three feet above the ground, resulting in the mower being vulnerable to tipping backward. This limits the maximum pitch angle of a slope that may be safely mowed before the front of the mower tips back causing a dangerous condition.
Accordingly, there is a need for an improved walk-behind lawn mower having a standing platform attached to the rear of the mower and positioned so that the center of gravity is located toward the center of the mower to provide a safer, more stable operating condition while being operated by an operator standing on the platform.
SUMMARY OF THE INVENTION
Therefore, in view of the problems associated with the above types of lawn mowers, it is an object of the present invention to provide a lawn mower having a platform attached to the rear of the mower for accommodating a standing operator, with the platform positioned in front of the rear wheel axles so that the center of gravity of the mower is toward the center of the mower near the engine. Positioning the center of the platform in front of the rear wheel axles greatly improves the stability and safety of the mower, especially on hilly terrain.
These and other objects are met by the lawn mower of the present invention. The lawn mower comprises a frame and a mower deck with an engine mounted thereon. The engine provides power to a plurality of cutting blades mounted within the mower deck and to a pair of rear drive wheels. The frame includes a substantially horizontal front portion supporting the mower deck and engine, and a substantially vertical rear portion. Operator controls are mounted to an operator console extending outwardly from the upper end of the rear portion of the frame.
The mower further comprises a platform positioned between the rear drive wheels and in front of a vertical plane created by the rotational axis of the rear wheels.
In some embodiments, a seat assembly is removably attached to the frame so that an operator can sit down or lean against the seat while operating the mower. The seat assembly includes an attachment mechanism designed to be removably attached to the rear frame of the mower. The seat is preferably a bicycle or bolster-type seat positioned at or near a vertical plane created by the rotational axis of the rear wheels, and substantially above the platform. The seat may also be used to relieve the body weight from fatiguing legs and feet of an operator.
The present invention provides many advantages over lawn mowers of the prior art. In particular, the operator will be less frightened, not having to walk all day long while mowing. In addition, the mower can be operated at higher ground speeds, since it not limited to an operator's walking speed. The present invention also moves the center of gravity forward several inches from prior art standing operator machines, thus allowing an operator to mow up steeper hills, and while accelerating, with improved stability and safety. The chances of tipping the mower are substantially reduced. Another advantage is that the centrifugal force occurring during turns causes the operator to feel a force toward the mower, rather than away, as was the case with prior standing operator mowers, giving the operator a more secure feeling. An additional benefit is eliminating the need to add forward ballast to the front of the mower to move the center of gravity forward, as demonstrated in prior art machines. This reduction of ballast has the further advantage of reducing tire forces on the ground, thus reducing tire marks on a freshly mowed lawn. Another benefit is that when the operator wishes to relive fatigue from standing, he or she can add a seat assembly on which to sit or lean during operation. An additional advantage is that any
Bland Mark C.
Scag Dane T.
Baxter William K.
Godfrey & Kahn S.C.
Great Dane Power Equipment, Inc.
Kovács Árpád F
Pezzuto Robert E.
LandOfFree
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