Multiple plow hitch

Claim 2

Hitch structure for connecting a pair of towed plows in echelon with each plow including a frame adjustably mounted on wheels for vertical movement, means acting between the frame and wheels to vertically move the frame on the wheels between raised transport and lowered working positions, and forwardly extending draft structure having a rear portion pivotally connected to the frame so that its forward portion can remain in a substantially constant vertical position with respect to the ground surface as the frame is moved between its raised and lowered positions, the hitch structure including a hitch tube having its forward end operatively connected to the forward end of the draft structure for the front plow and extending rearwardly to a rear end adjacent the rear portion of the forward plow, means on the rear end of the hitch tube for connection with the forward end of the draft structure for the rear plow, support means connected between a rear portion of the forward plow and a rear portion of the hitch tube for maintaining the rear portion of the hitch tube spaced from the ground surface and the forward plow, and the support means including means maintaining the rear portion of the hitch tube in a fixed vertical position with respect to the ground surface irrespective of vertical movement of the rear portion of the forward plow with respect to the ground surface.

Claim 3

The hitch structure set forth in claim 1 wherein the support means includes a first bracket secured to the hitch tube adjacent the rear end thereof, a second bracket secured to the forward plow adjacent the rear end thereof, and a pair of rigid upper and lower links each having its opposite ends pivotally connected to the first and second bracket.

Claim 4

The hitch structure set forth in claim 2 wherein the means for maintaining the rear portIon of the hitch tube in a fixed vertical position with respect to the ground surface includes extensible and retractable hydraulic cylinder means anchored between the second bracket and one of the links.

Claim 5

The combination of first and second drawn plows arranged in echelon and each including a frame adjustably supported on a forward wheel, rear furrow wheel means, and a land wheel, means for raising and lowering the frame on the wheels between raised transport and lowered working positions, and forwardly extending draft structure, the draft structure having a pivotal connection with the frame whereby, upon vertical movement of the frame the forward end of the draft structure can maintain a constant vertical position with respect to the group surface, and hitch means interconnecting the plows including a hitch tube having its forward end operatively connected to the forward end of the draft structure for the forward plow and its rear end connected to the forward end of the draft structure for the rear plow, support means connected between the hitch tube and the frame of the forward plow maintaining the rear portion of the hitch tube spaced from the ground surface and the forward plow, and the support means including means maintaining the rear portion of the hitch tube in a fixed vertical position with respect to the ground surface irrespective of vertical movement of the rear portion of the frame of the forward plow with respect to the ground surface.

Claim 6

The combination of first and second drawn plows arranged in echelon and each including a frame adjustably supported on a forward wheel, rear furrow wheel means, and a land wheel, means for raising and lowering the frame on the wheels between raised transport and lowered working positions, and forwardly extending draft structure, the draft structure having a pivotal connection with the frame whereby, upon vertical movement of the frame the forward end of the draft structure can maintain a constant vertical position with respect to the group surface, and hitch means interconnecting the plows including a hitch tube having its forward end operatively connected to the forward end of the draft structure for the forward plow and its rear end connected to the forward end of the draft structure for the rear plow, support means connected between the hitch tube and the frame of the forward plow maintaining the rear portion of the hitch tube spaced from the ground surface and the forward plow, and the support means including means maintaining the rear portion of the hitch tube in a fixed vertical position with respect to the ground surface irrespective of vertical movement of the rear portion of the frame of the forward plow with respect to the ground surface.

Claim 7

The combination set forth in claim 4 wherein the support means includes link means having an inner end pivotally connected to a rear portion of frame of the forward plow and an outer end pivotally connected to the hitch tube adjacent the rear end thereof, and the means maintaining the rear portion of the hitch tube in a fixed vertical position includes means operatively connected between the link means and the frame of the forward plow and responsive to upward movement of the frame of the forward plow to move the outer end of the link means downwardly with respect to the frame a corresponding amount and to downward movement of the frame of the forward plow to move the outer end of the link means upwardly with respect to the frame a corresponding amount.

Claim 8

The combination set forth in claim 4 wherein extensible and retractable hydraulic cylinder means is operatively connected between the frame and rear furrow wheel means of the forward plow to raise and lower the frame of the forward plow on its rear furrow wheel means, the means connected between the frame of the forward plow and the link means includes an extensible and retractable hydraulic cylinder means having one end pivotally connected to the frame and another end pivotally connected to the link means, and wherein fluid line means interconnects the cylinder means connected between the frame and link means in series with the cylinder means connected between the frame and rear furrow wheel means.

Claim 9

The combination set forth in claim 6 wherein each of the hydraulic cylinder means includes a cylinder having an anchor and a rod end and a piston and rod assembly slidably mounted therein with the rod projecting from the rod end of the cylinder, the anchor end of the cylinder of the cylinder means for the furrow wheel means is pivotally connected to the frame and the rod thereof is pivotally connected to the furrow wheel means so that upon extension and retraction the frame is raised and lowered, respectively, on the furrow wheel means, the anchor end of the cylinder of the cylinder means connected between the frame and link means is pivotally connected to the frame above the pivotal connection between the frame and link means and the rod thereof is pivotally connected to the link means so that upon extension and retraction the rear portion of the hitch tube is lowered and raised, respectively, with respect to the frame of the forward plow, and the fluid line means interconnects the rod end of the cylinder for the furrow wheel means with the anchor end of the cylinder For the hitch tube.

Claim 10

The combination set forth in claim 7 wherein the effective cross-sectional area of the rod end of cylinder for the furrow wheel means is equal to the effective cross-sectional area of the anchor end of the cylinder for the hitch tube.

Claim 11

The combination set forth in claim 8 wherein each of the cylinders is provided with a bypass circuit means which affords free flow of fluid through the cylinders when they are fully extended whereby the cylinder means will be synchronized each time the frame is fully raised on the rear furrow wheel means.

Claim 12

The combination set forth in claim 7 wherein a first bracket is secured to the frame of the forward plow, a second bracket is secured to the rear portion of the hitch tube, and the link means includes a pair of upper and lower links having their ends pivotally connected to the first and second brackets whereby the brackets and links form a four-bar linkage.

Claim 13

For use with a tractor having a drawbar and a hydraulic system with at least two independently operable remote functions, first and second drawn plows arranged in echelon and each including a frame adjustably mounted on wheel means and having a plurality of extensible and retractable hydraulic cylinder means operatively connected between the frame and wheel means to raise and lower the frame on the wheel means between raised transport and lowered working positions, forwardly extending draft structure pivotally connected to the frame, fluid line means connecting the hydraulic cylinders on each plow in series and including means for connection with one of the remote functions on the tractor whereby the two plows can be raised and lowered independently, means on the forward end of the draft structure of the first plow for connection with the tractor drawbar, and means connecting the plows in echelon including an elongated hitch tube having its forward and rear ends connected to the forward ends of the draft structure for the first and second plows respectively, and support means for the rear end of the hitch tube including link means having an inner end pivotally connected to the frame of the first plow and an outer end pivotally connected to the hitch tube, an additional extensible and retractable hydraulic cylinder means operatively connected between the frame of the first plow and the link means to lower and raise the hitch tube relative to the frame of the first plow, and additional fluid line means connecting the additional hydraulic cylinder means in series with the serially connected cylinder means for raising and lowering the first plow, whereby, when the frame of the first plow is raised or lowered on the wheel means, the rear end of the hitch tube is moved relative to the frame of the first plow a corresponding amount in the opposite direction and is thereby maintained at a substantially constant height.

Claim 14

For use with a tractor having a drawbar and a hydraulic system with at least two independently operable remote functions, first and second drawn plows arranged in echelon and each including a frame adjustably mounted on wheel means and having a plurality of extensible and retractable hydraulic cylinder means operatively connected between the frame and wheel means to raise and lower the frame on the wheel means between raised transport and lowered working positions, forwardly extending draft structure pivotally connected to the frame, fluid line means connecting the hydraulic cylinders on each plow in series and including means for connection with one of the remote functions on the tractor whereby the two plows can be raised and lowered independently, means on the forward end of the draft structure of the first plow for connection with the tractor drawbar, and means connecting the plows in echelon including an elongated hitch tube having its forward and rear ends connected to the forward ends of the draft structure for the first and second plows respectively, and support means for the rear end of the hitch tube including link means having an inner end pivotally connected to the frame of the first plow and an outer end pivotally connected to the hitch tube, an additional extensible and retractable hydraulic cylinder means operatively connected between the frame of the first plow and the link means to lower and raise the hitch tube relative to the frame of the first plow, and additional fluid line means connecting the additional hydraulic cylinder means in series with the serially connected cylinder means for raising and lowering the first plow, whereby, when the frame of the first plow is raised or lowered on the wheel means, the rear end of the hitch tube is moved relative to the frame of the first plow a corresponding amount in the opposite direction and is thereby maintained at a substantially constant height.

Claim 15

The invention set forth in claim 11 wherein the effective cross-sectional area of each cylinder means is equal to the effective cross-sectional area of the cylinder means to which it is connected by the fluid line means so that the cylinder means on each plow are simultaneously moved through equal distances.

Claim 16

The invention set forth in claim 12 wherein each cylinder means is provided with a bypass circuit means which provides free flow of fluid through the cylinder means when their respective frame is fully raised to thereby synchronize the cylinder means each time their respective frame is fully raised.