Harvesters – Cutting and conveying – Reciprocating-cutter type
Reexamination Certificate
1999-05-28
2001-08-14
Will, Thomas B. (Department: 3671)
Harvesters
Cutting and conveying
Reciprocating-cutter type
C056S364000
Reexamination Certificate
active
06272823
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a header for a harvesting machine and in particular to a preformed header frame. When the header is supported above the ground intermediate the ends of the frame, loading of the frame deflects the ends of the frame to a position in which the cutterbar assembly along the frame front edge assumes a substantially straight and horizontal position.
2. Description of the Related Art
To increase harvesting efficiency, harvesting machines, such as combines, have increased in size and capacity over the years. With this increasing capacity, the detachable header used for picking a crop has increased in width as well. A wider header increases efficiency by reducing the number of passes through the field required by the harvesting machine to cover the entire field. However, the increased width of the header has resulted in increased difficulties in maintaining the cutterbar assembly at the front of the header in a straight orientation for proper operation. Headers are typically supported by the harvesting machine at a location in the middle of the header. When the header is suspended above the ground, the ends of the header tend to deflect downward under the load. As headers increase in width, it is harder to prevent this deflection. Deflection of the cutterbar assembly from a straight position will reduce the life of the knife back of the cutterbar assembly and the knife drive motor. In addition, if the ends of the cutterbar assembly are lower than the center portion, the reel will not be at a constant distance from the cutterbar across the entire length of the cutterbar assembly. Proper crop movement over the cutterbar will only occur over part of the header width.
Header manufacturers have taken various approaches to address this problem. One approach is to build a header frame with a main beam having multiple round tubes joined end to end with the center of the beam formed by larger tubes. A number of braces and gussets connect to the main beam to form a truss like structure to reduce the deflection. Another approach is to build a main beam in which lengthwise tube has a second tube placed thereon at a center portion of the longer tube. Gussets extending lengthwise from the ends of the second tube gradually reduce in section height toward the ends of the main beam. The individual pieces are welded together with the intent that the main beam will resist deflection under load. The use of gauge wheels at the outer ends of the header can also help control deflection.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a header having a preformed frame with a single tube main beam in which the ends of the main beam are raised upward and forward of an intermediate portion of the main beam so that when suspended, the deflection in the main beam returns the cutterbar assembly to a substantially straight and horizontal position.
The present invention provides a header frame having a main beam that is constructed of a single piece tube extending from end to end of the header. The single piece tube is preformed by vertically cutting the tube at a location intermediate the two ends. The tube is then bent to raise the ends upward and forward. A cap that covers the top, front and rear walls of the beam is placed over the main beam in the intermediate portion to cover the cut. A gusset plate is placed on the bottom of the single piece tube at the location of the cut. The gusset plate, cap and single piece tube are welded together to form a tube that is preformed. When the header is supported above ground, the deflection brings the cutterbar, not the main beam, to a substantially straight and horizontal position.
In a preferred embodiment, the single piece tube is vertically cut downward from the top surface through the top, front and rear walls. The cut extends partially in the bottom wall, from both the front and rear walls. The single piece tube is then bent upward and forward at the cut. The cap and gusset are shaped to fit the bent, single piece tube and are welded to the tube to maintain the preformed shape of the tube. The preformed shape not only counters the loading of the main beam but also counters the welding and hole punching effects on the beam.
REFERENCES:
patent: 3659405 (1972-05-01), Miller
patent: 4409780 (1983-10-01), Beougher et al.
patent: 4487004 (1984-12-01), Kejr
patent: 6029429 (2000-02-01), Fox et al.
Deere & Company
Petravick Meredith C.
Will Thomas B.
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