Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
2001-09-04
2004-08-17
Boehler, Anne Marie (Department: 3611)
Land vehicles
Wheeled
Articulated vehicle
C056S014900, C172S074000, C172S248000, C180S053100
Reexamination Certificate
active
06776432
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a towed implement that is towed and mechanically powered by a towing vehicle. In particular, this invention relates to an adapter assembly carried by the drawbar of a towing vehicle for connection to a towed implement having a pull-through swivel gearbox assembly.
BACKGROUND OF THE INVENTION
Pull type implements have been used in farming operations for decades. For example, the agricultural implement may be a mower designed to cut and process hay or other crops. The implement may also be configured as a forage harvester, hay recovery implement, baler, sprayer, or ground breaking implement. Typically, the implement is towed and powered by a towing vehicle such as a tractor. A power-take-off shaft (PTO) of the tractor typically provides mechanical power to the implement.
The implement is typically connected to the tractor by a pivoting draft tongue. In many implements, a hydraulic swing cylinder interconnects the implement frame and the draft tongue. The hydraulic cylinder controls the pivotal movement of the draft tongue. The pivoting tongue may be positioned so that the implement is directly behind the tractor or to the left or right side of the tractor. As previously indicated, the implement is mechanically powered by the PTO on the tractor. Hydraulic pressure for the implement is provided by the hydraulic system of the towing vehicle.
There are two common methods of attaching the draft tongue of the implement to the towing vehicle. One is to connect the draft tongue directly to the drawbar of the towing vehicle. A simple hitch pin can be used to drop through a hole in the draft tongue and into a hole in the towing vehicle drawbar. The implement tongue may also have a ball joint to allow freedom of rotation about the vertical (yaw) axis, the horizontal (pitch) axis and the fore and aft (roll) axis or the hitch pin joint may be loose enough to allow the rotation needed.
The other method of attaching the draft tongue of an implement to a towing vehicle is to use a swivel hitch on the implement. A swivel hitch involves a set of gearboxes, one above the other, with a connecting drive shaft between them. The gearboxes can swivel relative to each other. The relative swivelling motion becomes the vertical (yaw) axis of rotation.
Typically, the swivel hitch has a frame member that pivots on the same yaw axis as the swivel gearboxes and connects to the three point hitch assembly on the towing vehicle. The upper gearbox Is fixed to the draft tongue. The lower gearbox and swivel hitch frame pivot relative to the upper gearbox and follow the tractor as it turns.
The advantage of the swivel hitch over the standard pinned connection is that the yaw axis is further behind the towing vehicle, allowing for much sharper turns. With a pinned drawbar connection, the hitch point is close to the tractor. Thus the tractor can not turn sharply because the rear tire will engage the draft tongue of the implement.
There are two types of swivel hitch designs common in the industry. One is a pull-through design wherein the gearboxes are connected structurally to transmit load from the swivel hitch frame to the draft tongue. The other design involves a swivel hitch frame that is connected structurally to the draft tongue so that the implement does not transmit any structural load through the gearboxes.
The advantage of the pull-through design is that it is a much simpler design and does not require a device to guide the lower gearbox to follow the tractor, since the swivel hitch frame is connected directly to the lower gearbox.
Preferably a trunnion assembly is also located adjacent the gearbox assembly on the draft tongue of the implement. The trunnion assembly allows the implement to rotate or tilt about the fore and aft longitudinal roll axis.
One major drawback to any swivel hitch is that many tractors are not equipped with a three-point hitch system. Also, some operators find the lower links of a three-point hitch cumbersome to hook up.
For these reasons, a mechanism to adapt a tractor drawbar for connection to the swivel hitch of a pivoting draft tongue is desired.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a drawbar hitch adapter assembly that allows a mechanically powered implement having a pull-through gearbox assembly to connect to the drawbar of a tractor.
Thus, one embodiment of the invention includes an adapter assembly for a towing vehicle having a drawbar hitch for connecting a towed implement having a pull-through swivel gearbox assembly to the towing vehicle. The adapter assembly includes a drawbar extension portion having a horizontal cross pin, a clamp assembly to secure the drawbar extension portion to the drawbar, an adapter frame portion having an open hook to engage the cross pin and a trunnion assembly to couple the adapter frame portion to the swivel hitch assembly.
The adapter assembly may further include a pivotally mounted pawl on the adapter frame to rotate from an open position to a closed position to secure the open hook in the closed position.
The adapter assembly may also include a flat vertical surface on the hook for contact by the cross pin when the tow vehicle is moved into a hitching position with the towed implement so as to indicate an alignment position of the cross pin relative to the hook.
REFERENCES:
patent: 4714123 (1987-12-01), Ermacora et al.
patent: 5158500 (1992-10-01), McLean
patent: 5186483 (1993-02-01), Sheppard
patent: 5339907 (1994-08-01), Roth
patent: 5531283 (1996-07-01), Austin et al.
patent: 5647604 (1997-07-01), Russell
patent: RE35835 (1998-07-01), Eidam et al.
patent: 6203049 (2001-03-01), Gibson
patent: 6328327 (2001-12-01), Ligouy
Sales Literature for New Holland DISCBINE Disc Mower-Conditioners, published Sep. 14, 1999, printed in U.S.A.
Harkcom Melanie W.
Stiefvater Thomas L.
Young Terry A.
Boehler Anne Marie
New Holland North America Inc.
Stader John William
Webb Collin A.
LandOfFree
Drawbar adapter for pull-through swivel hitch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Drawbar adapter for pull-through swivel hitch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drawbar adapter for pull-through swivel hitch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3354289