The present invention relates generally to the field of lawn mower decks that are attached to tractors. More particularly, the present invention relates to an adjustable height lawn mower deck for a tractor having a three point hitch.
Owners of agricultural tractors are commonly able to mow grass by attaching a lawn mower deck under the tractor. Typical lawn mower decks include a height adjustment mechanism that allows the tractor operator to adjust the height of the lawn mower deck, and thereby adjust the length of cut of the grass. Many such height adjustment mechanisms are operable while the operator is sitting on the tractor and typically include a handle within a linear track having detents that correspond to different cut heights. The linear movement of the handle causes such height adjustment mechanisms to be susceptible to unintended and undesired changes to the cut height setting due to vibration of the tractor as it rides over uneven surfaces or inadvertent operator contact with the handle. Other existing height adjustment mechanisms are foot pedal actuated, wherein an operator selects a desired height of cut by pressing on a pedal attached to a bar within a linear track having detents that correspond to different cut heights.
Various attempts have been made to prevent such unintended changes to the cut height setting, including revised detent designs, adjustment mechanisms using cams to adjust height, and rotary detent systems. Some of these systems involve the use of tools and other systems have foregone adjustment by the operator from the operator's seat entirely, instead employing a system that solves the problem of unintended adjustment, but necessitates leaving the operator's seat and removing and replacing a pin from a bracket to set the height of cut.
As such, there is a need for a mower deck height adjustment mechanism that is not susceptible to unintended and undesired changes to the cut height, and may be adjusted by the operator from the operator's seat without the use of tools.
The present invention relates to an adjustment mechanism for adjusting the height of cut of a lawn mower attachment for a tractor having a three point hitch. The lawn mower deck is removably attached to the tractor by a height adjustment linkage. The height adjustment linkage includes a rockshaft bracket removably attached to a rockshaft arm of the three point hitch. The height adjustment linkage also includes a height bar that is selectively engaged with a rotatable cam. The rotatable cam is connected to a camshaft passing through a hole in an adjustment plate and having an adjustment dial at a first end. The adjustment dial is mounted to the tractor, preferably within reaching distance of the tractor operator when seated in an operator's seat. The rotatable cam has a plurality of bearing surfaces, each of which correspond to a different height of cut. The height bar is engaged with one of the plurality of bearing surfaces when the rockshaft arms are in a lowered position and disengaged when the rockshaft arms are in a raised position. The adjustment plate is mounted to the tractor and includes a plurality of holes that align the bearing surfaces with the height bar when a locking pin attached to the adjustment dial is engaged with one of the plurality of holes.
It will be understood by those skilled in the art that one or more aspects of this invention can meet certain objectives, while one or more other aspects can lead to certain other objectives. Other objects, features, benefits and advantages of the present invention will be apparent in this summary and descriptions of the disclosed embodiment, and will be readily apparent to those skilled in the art. Such objects, features, benefits and advantages will be apparent from the above as taken in conjunction with the accompanying figures and all reasonable inferences to be drawn therefrom.
The present invention relates to a lawn mower deck attachment for a tractor, wherein the height of cut may be adjusted by a tractor operator using a dial height selector.
To adjust the height of cut, an operator first raises the tractor's rockshaft arms, which in turn raise three point hitch arms 116, which engage the adjustable linkage 106 causing the height adjustment pin 112 to raise off of the tow bar 114, thereby allowing the pin to be removed and replaced in a new hole 110. Thus, in order perform the height of cut adjustment using the prior art height adjustable lawn mower deck attachment 100, the tractor operator must raise the rockshaft arms so the height adjustment pin 112 is disengaged from the tow bar 114, exit the seat of the tractor and walk to the location of the adjustment mechanism 108, remove the height adjustment pin from the adjustment mechanism, adjust the position of the adjustment mechanism, replace the height adjustment pin, return to the seat of the tractor, and finally lower the rockshaft arms so that the height adjustment pin re-engages the tow bar. This is a cumbersome process that is time consuming, may require tools, and may also be physically strenuous.
Turning now to
The adjustable linkage 206 includes a rockshaft bracket 208 that is removably attached to one of the rockshaft arms 210 of the tractor's three point hitch by two plates 209 and a plurality of nuts 211 and bolts 213. Of course, any other suitable attachment means may be used without departing from the invention. The adjustable linkage 206 translates movement of the rockshaft arm 210 to selectively engage a height bar 212 with a dial adjuster 300, which allows an operator to adjust the height of cut of the mower deck attachment 200 without tools and without leaving the seat of the tractor.
During normal operation of the lawn mower deck attachment 200, the operator positions the rockshaft arm 210 in a lowered position, which causes height bar 212 to engage dial adjuster 300 and thereby set the height of cut. The movement of the rockshaft arm 210 is typically controlled by the tractor operator while sitting in the seat of the tractor. Similarly, the dial adjuster 300 is installed on the tractor 20 so that it may also be operated by the operator while sitting in the seat of the tractor. Of course, the dial adjuster 300 may be located in any suitable location without departing from the invention, but placing the dial within reaching distance of the operator is the preferred location.
Turning now to
The dial adjuster 300 further includes a plate 306 having a plurality of holes 308 that are indexed to a particular bearing surface 304 and a pin 310 attached to a collar 312 that selectively engages one of the holes to set the cut height. In the embodiment shown, the collar 312 is spring loaded to prevent the pin 310 from inadvertently disengaging the hole 308. A spring 314 is captured between the collar 312 and a dial 316, which is fixed to a camshaft 318. A set screw 315 secures the dial 316 to the collar 316, but any other suitable means may alternatively be used. The camshaft 318 is attached to the cam 302 and rotates the cam when the dial 316 is rotated by the tractor operator. To disengage the pin 310 from the hole 308, the operator simply pulls up on the collar, thereby allowing the dial to freely rotate. Alternatively, the collar 312 and dial 316 may be combined as a single component, the dial including the pin 310, so that an operator would simply lift the dial itself, which would disengage the pin 310 from the hole 308, thereby allowing the dial to freely rotate. In such an alternative embodiment, a spring attached to the crankshaft 318 may bias the dial 316 toward the plate 306. The dial 316 may or may not be biased toward the plate 306 by a spring or any other suitable means without departing from the invention.
Although the invention has been herein described in what is perceived to be the most practical and preferred embodiments, it is to be understood that the invention is not intended to be limited to the specific embodiments set forth above. Rather, it is recognized that modifications may be made by one of skill in the art of the invention without departing from the spirit or intent of the invention and, therefore, the invention is to be taken as including all reasonable equivalents to the subject matter of the appended claims and the description of the invention herein.
This application is based on and claims priority to U.S. Provisional Patent Application No. 61/898,645 filed on Nov. 1, 2013, which is incorporated herein by reference in its entirety for all purposes.
Number | Date | Country | |
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61898645 | Nov 2013 | US |