Earth working – Mast type hitch
Reexamination Certificate
1999-11-24
2002-02-19
Pezzuto, Robert E. (Department: 3671)
Earth working
Mast type hitch
C172S272000
Reexamination Certificate
active
06347671
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to turf maintenance equipment, and ore particularly to an improved system for attaching an “operating unit” (e.g., a cutting reel) to a traction vehicle.
BACKGROUND OF THE INVENTION
Although the present invention can be applied to a wide variety of turf maintenance equipment, it is particularly well suited for use with multi-purpose turf maintenance machines used primarily as power turf mowers. Although many types of power turf mowers are known, such equipment may generally be classified according to the type of cutting unit it employs. A rotary cutting unit usually includes one or more rigid, generally straight, steel blades rotated within a housing (“deck”) about a vertical axis to strike and sever the grass or other vegetation at a predetermined height above the ground. A reel cutting unit, on the other hand, typically includes a reel having several curved blades rotated about a horizontal axis. The curved blades of the reel work in conjunction with a fixed blade, or “bedknife,” to shear the grass in a scissorslike manner.
While rotary cutting units are suitable for many purposes, it is generally perceived that reel cutting units provide a higher quality cut. The present invention relates primarily though not exclusively to reel-type turf mowers, and the remainder of the discussion will focus accordingly.
Power turf mowing equipment may also be categorized based on the method used to propel the cutting units. Generally, there are walk-behind, riding, and towed turf mowers. The present invention relates primarily to riding turf mowers and, more specifically, those riding turf mowers with three reel-type cutting units, generally referred to as “triplex mowers.”
Triplex mowers typically include a traction vehicle supported by a plurality of wheels, including one or more traction (i.e., powered) wheels; a prime mover supported by the vehicle frame and connected through a transmission to the traction wheel(s); and three cutting units powered by the prime mover, two cutting units mounted generally ahead of the front wheel(s) and laterally offset about the longitudinal or fore-and-aft axis of the traction vehicle, and one cutting unit mounted generally between the front and rear wheels and laterally centered between the front cutting units. Typically, the two forward cutting units of a triplex mower, being laterally and symmetrically offset, leave an uncut section therebetween during operation. Being centered between the front cutting units, the rear cutting unit then spans the uncut section and overlaps the mowed path of both forward cutting units. Consistent mowing across the full span of the mower is thus obtained.
Triplex mowers further include a system designed to attach the cutting units to the vehicle. In addition to securing the cutting units to the traction vehicle, the attachment system also permits lifting of the cutting units from their lowered, working position to their raised, transport position. In the working position, the attachment system preferably permits the cutting units to “float” relative to the traction vehicle. That is, the cutting units are independently and separately supported so that they can follow the contours and undulations of the ground irrespective of the motion of the traction vehicle. In the transport position, the front cutting units are typically raised such that the outer ends are pivoted upwardly (and sometimes inwardly) to reduce the overall width of the mower (the rear cutting unit is typically lifted only vertically). In this configuration, the mower is more easily maneuvered between obstacles; e.g., trees and fences. Movement of the front cutting units between the working and transport positions is often accomplished through simple pivotal motion. That is, each front cutting unit pivots about a horizontal or “wing” axis which is parallel to the vehicle longitudinal axis and near the inboard end of the cutting unit. By properly locating the wing axis, the preferred range of motion (i.e., movement between working and transport positions) is obtained.
In addition to mechanically securing the implement or “operating unit” to the traction vehicle, the attachment system preferably provides drive power to the implement. Two different types of drive systems are commonly utilized with triplex mowers. The first implement drive system uses a hydraulic motor to drive each independent reel. The hydraulic motor is usually mounted to one of the reel ends and connected by a series of flexible hoses to a pump located on the traction vehicle frame. This drive system is advantageous in that the flexible hose attachment can easily accommodate the range of cutting unit motion required during operation and during movement between the working and transport positions. However, providing separate hydraulic motors for each reel is costly. For this reason, some triplex mowers utilize a belt drive system. Belt drive systems employ a driven pulley located on each reel that is connected by a flexible drive belt to a driving pulley located on the traction vehicle. While more economical, belt drive systems require an attachment system that provides the necessary belt tension when the cutting units are in the working position yet does not interfere with movement of the cutting units during operation (i.e., floating) or during movement to the transport position. The present invention is primarily, though not exclusively, directed to a triplex mower having a belt drive system for supplying power to the cutting reels.
While the attachment system of the present invention could be used with a dedicated, single-purpose turf mower, it is preferably used in conjunction with a multi-purpose turf machine. Such multi-purpose turf machines, by definition, must accommodate other implements or “operating units” (e.g., blowers, rotary brooms, snow throwers and dozer blades) in addition to reel cutting units. Some of these other implements or “operating units” generally require the ability to be either vertically lifted or “pitched” (about a transverse horizontal axis running generally perpendicular to the vehicle's fore-and-aft longitudinal centerline) rather than pivoted about a longitudinal horizontal axis, or “wing axis.” For example, in order to effectively transport a snow thrower or dozer blade, it must be vertically elevated from its working position, rather than pivoted about a “wing axis” as reel cutting units typically require. It is therefore beneficial for an attachment system of a multipurpose turf machine to include the capability to either lift (or pitch) a given implement, or pivot it about a wing axis, or both.
Many different types of attachment systems that provide this dual motion (i.e., lift or pitching motion on the one hand, and a “wing” type motion on the other hand) have been tried over the years. With many attachment systems, one actuating device (e.g., hydraulic cylinder) is used to provide the lifting or pitching motion, while another actuating device is used to provide the wing type motion. While such attachment systems have proven to be adequate, the use of multiple actuating devices can add considerable cost and complexity to the mower. Thus, an attachment system that can accomplish the desired operating unit motion more economically and with less complexity is highly desirable. Ideally, the attachment system can provide this dual motion with only one actuating device (e.g., hydraulic cylinder).
Another preferred feature of an operating unit attachment system is the ability to permit implements to be quickly and easily attached and removed from the traction vehicle. Failure of the attachment system to permit easy attachment significantly reduces versatility of the machine. Although such quick-attach systems are known, many are generally perceived to sacrifice quality of cut (when turf cutting units are installed) in favor of ease of attachment.
Thus, there are several challenges associated with attaching an operating unit (e.g., a reel type cutting unit) to a multi-purpose turf maintenance vehicle.
Dutsch Pedro
Hauer Eckhard
Lindstrom Kris
Oehler Wolfgang
Stiller Daniel G.
Miller James W.
Pezzuto Robert E.
The Toro Company
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