Earth working – With wheel substitute – Spaced parallel runners with tool mounted therebetween
Reexamination Certificate
2000-05-24
2001-10-30
Pezzuto, Robert E. (Department: 3671)
Earth working
With wheel substitute
Spaced parallel runners with tool mounted therebetween
C172S445100, C404S118000
Reexamination Certificate
active
06308785
ABSTRACT:
BACKGROUND
The present invention generally relates to towable devices which are used to grade ground surfaces or spread various materials over the ground surface where it is desirable to obtain a particular finished grade of ground surface or to blend additives into the soil. Such grater-spreader devices are used for a variety of purposes, such as applying paving materials, grading land for construction, and preparing land for agricultural purposes. More particularly, the present invention relates to a grader-spreader adapted to being towed by a tractor having a three-point hitch, where the blades of the apparatus readily adjust to a desired width. An additional feature of the present invention is that the angle and elevation of the cutting blades with respect to the ground surface are readily adjustable, thus allowing the operator to obtain a particular finished grade or slope.
It has been long known that devices towable by tractor provide an efficient and economical means of grading a ground surface and for applying various materials to the ground surface. While self-propelled grading and spreading machinery may accomplish the same task as towable devices, self-propelled machines are expensive, require substantial maintenance, and are often complicated to operate. Because towable devices are propelled by an all-purpose tractor, the devices are relatively inexpensive, simple to operate, and require less maintenance than self-propelled grading and spreading devices.
It has also been a long recognized need that towable grader-spreaders should be adaptable to provide service in a variety of different working conditions. If a grader-spreader device is used in a large open field to prepare the ground surface for planting crops, the operator may desire to adjust the device to obtain a virtually flat surface. However, if the device is used to spread asphalt on a roadway, it is often desired to obtain a final surface with sufficient slope to allow rain and spilled materials to rapidly drain off of the roadway surface.
The invention described in U.S. Pat. No. 4,320,988, issued to Seal on Mar. 23, 1982, discloses a towable grader-spreader utilizing a plurality of cutting blades adjustable in depth and angular position. The patent discloses a device which utilizes a plurality of cutting blades which can function as grader blades or as a spreader. The blades of the invention are adjustable both in depth and in angular position, where the respective ends of the blades may be positioned at different cutting depths from each other so as to vary the angle of a cut on a surface. The blades of the invention are positioned by a hydraulic ram adjustment mechanism. The cutting blades are mounted between a pair of side runners. The width of the device is fixed because the side runners are fixedly attached to one another.
The grader-spreader of U.S. Pat. No. 5,191,943 issued to Minor et al. on Mar. 9, 1993, discloses a pair of transversely extending blades rigidly mounted between two side members. While the ends of the blades of the grader-spreader in the '943 patent are vertically adjustable, the width of the device is fixed.
SUMMARY OF THE INVENTION
An adjustable grader-spreader is disclosed which may be towed by a tractor or other vehicle adaptable to a three-point hitch, where the operator, from the operator's seat on the tractor, may make various adjustments to the grader-spreader to accommodate the immediate needs presented by the working conditions. Unlike other prior art devices, the width of the grader-spreader may be either increased or decreased, depending upon the requirements of the particular job requirements. The elevation of the blade edges relative to the work surface may also be adjusted. The adjustments are made through hydraulic and/or electric actuating devices which are commonly known to those skilled in the art.
The grader-spreader disclosed herein includes a blade frame assembly which is configured from a plurality of blade frames with a blade edge fastened at the bottom of each blade frame. The blade frames are slideably connected to one another so that the blade frames have an adjustable overlap. Actuators are connected to the blade frames in such a manner that the operator may remotely change the total width of the grader-spreader from the operator's position in the towing vehicle. In one embodiment, ground engaging skids are attached to either side of the blade frame assembly.
In one embodiment of the grader-spreader, a plurality of front stabilizers and rear stabilizers connect adjacent blade frames, providing the means for slideably connecting the adjacent blade frames. One means of sliding adjacent blade frames with reference to one another is by the use of hydraulic actuating rams. In the preferred embodiment, the blade frame assembly is comprised of a left blade frame, a right blade frame, and a center blade frame.
Elevating means may be used for adjusting the vertical positions of the left and right ground engaging skids thereby adjusting the level and angle of the blade edges with respect to the ground surface. One means of raising or lowering the ground engaging skids is by an electrical motor operating a screw jack connected to each ground engaging skid.
In an alternative embodiment, the ground engaging skids may be replaced by wheels on each side of the grader-spreader. The wheels may be independently raised or lowered with respect to the blade frame assembly by the same type of actuating means used to raise or lower the ground engaging skids.
REFERENCES:
patent: 3704752 (1972-12-01), Piacentino
patent: 4320988 (1982-03-01), Seal
patent: 4630686 (1986-12-01), Ausmus, Jr.
patent: 5191943 (1993-03-01), Minor
patent: 5191944 (1993-03-01), Thorn
patent: 5332331 (1994-07-01), Critz et al.
patent: 5511625 (1996-04-01), Mork
patent: 5599135 (1997-02-01), Delaurenti
Duncan James M.
Pezzuto Robert E.
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