Hydraulic plow steering

Claim 2

In an earth working implement having a steering system including a master cylinder and piston interconnected between the front of the implement and the rear of a prime mover, and a slave cylinder and piston pivotally connected between the rear of the implement and a steering wheel, with said cylinders being interconnected by a pair of separate conduits to define a closed hydraulic circuit, said slave cylinder steering the earth working implement in response to hydraulic fluid circulated through said pair of conduits by said master cylinder in response to steering of the prime mover, said earth working implement further including means for lifting the implement relative to the steering wheel, wherein said lifting means includes a second hydraulic circuit through which hydraulic fluid flows under pressure, the improvement of means for purging entrapped air from said master and slave cylinders and from each of said separate conduits comprising a purging conduit connecting each conduit of the steering system to said second hydraulic circuit, and normally closed valve means in each of said purging conduits isolating said second hydraulic circuit from said closed hydraulic circuit, said valve means being openable for flowing hydraulic fluid between the two hydraulic circuits.

Claim 3

In a semi-mounted plow having a steerable furrow wheel and a closed master-slave hydraulic steering system wherein a master cylinder responsive to tractor steering movement is hydraulically connected by a pair of conduits to a slave cylinder located at the furrow wheel to correspondingly actuate the slave cylinder so that the furrow wheel accurately tracks the tractor, said plow further including means for lifting the plow relative to the steerable furrow wheel, and an external hydraulic system having a source of hydraulic fluid under pressure, a sump and a pair of hydraulic conduits interconnecting said sump and said lifting means, the improvement of means for purging entrapped air from hydraulic fluid in the closed master-slave system, including purging conduits interconnecting each of the master-slave system conduits to respective conduits of the external hydraulic system, and manually actuatable valves in said purging conduits, said valves being normally closed and being openable to accommodate circulation of hydraulic fluid from said external system into and through said master-slave hydraulic system and then back to said sump for purging air from said master-slave system.

Claim 4

In a semi-mounted plow having a steerable furrow wheel and a closed master-slave hydraulic steering system wherein a master cylinder responsive to tractor steering movement is hydraulically connected by a pair of conduits to a slave cylinder located at the furrow wheel to correspondingly actuate the slave cylinder so that the furrow wheel accurately tracks the tractor, said plow further including means for lifting the plow relative to the steerable furrow wheel, and an external hydraulic system having a source of hydraulic fluid under pressure, a sump and a pair of hydraulic conduits interconnecting said sump and said lifting means, the improvement of means for purging entrapped air from hydraulic fluid in the closed master-slave system, including purging conduits interconnecting each of the master-slave system conduits to respective conduits of the external hydraulic system, and manually actuatable valves in said purging conduits, said valves being normally closed and being openable to accommodate circulation of hydraulic fluid from said external system into and through said master-slave hydraulic system and then back to said sump for purging air from said master-slave system.

Claim 5

adjusting the steering angle of the wheel relative to the master cylinder and piston by adjusting the slave piston relative to the master piston postion and thereby flowing hydraulic fluid between the slave cylinder and the independent hydraulic source; and

Claim 6

adjusting the steering angle of the wheel relative to the master cylinder and piston by adjusting the slave piston relative to the master piston postion and thereby flowing hydraulic fluid between the slave cylinder and the independent hydraulic source; and

Claim 7

alternately interconnecting each of said master-slave hydraulic conduits to respective conduits of said independent hydraulic circuit;

Claim 8

alternately interconnecting each of said master-slave hydraulic conduits to respective conduits of said independent hydraulic circuit;

Claim 9

A semi-mounted plow, comprising: a generally horizontal frame member pivotally connected to the rear of a prime mover about a generally vertical pivot axis; a wheel steerably mounted to the plow frame member about a generally vertical rotational steering axis; linkage means for raising and lowering the frame relative to the steering wheel; a hydraulic piston and cylinder connected between the frame and linkage means for effecting said raising and lowering, said cylinder connected to a hydraulic power source on said prime mover by a first pair Of hydraulic lines; a master piston and cylinder connected between the forward end of said frame and the rear of said vehicle, said piston being reciprocated within said cylinder in response to angular directional variations between said vehicle and frame; a steering piston and cylinder connected between the rear of said frame and the steering wheel; a second pair of hydraulic lines interconnecting the master cylinder and steering cylinder; hydraulic fluid within said master cylinder, steering cylinder, and second pair of hydraulic lines, said hydraulic fluid reciprocating the steering piston in direct relationship to reciprocation of said master piston to rotate the steering wheel so that the frame follows the same turning arc as the vehicle; a third pair of hydraulic lines, one line of said third pair being connected at its opposed ends to one of the hydraulic lines of said first and second pairs of hydraulic lines, the other line of said third pair being connected at its opposed ends to the other lines of said first and second pairs of hydraulic lines; a valve in each line of said third pair of hydraulic lines, said valves being (1) openable to remove entrapped air from the hydraulic steering system and to replenish any loss of hydraulic fluid and (2) closeable to isolate the hydraulic steering circuit from the hydraulic circuit for raising and lowering the frame.

Claim 10

A semi-mounted plow, comprising: a generally horizontal frame member pivotally connected to the rear of a prime mover about a generally vertical pivot axis; a wheel steerably mounted to the plow frame member about a generally vertical rotational steering axis; linkage means for raising and lowering the frame relative to the steering wheel; a hydraulic piston and cylinder connected between the frame and linkage means for effecting said raising and lowering, said cylinder connected to a hydraulic power source on said prime mover by a first pair Of hydraulic lines; a master piston and cylinder connected between the forward end of said frame and the rear of said vehicle, said piston being reciprocated within said cylinder in response to angular directional variations between said vehicle and frame; a steering piston and cylinder connected between the rear of said frame and the steering wheel; a second pair of hydraulic lines interconnecting the master cylinder and steering cylinder; hydraulic fluid within said master cylinder, steering cylinder, and second pair of hydraulic lines, said hydraulic fluid reciprocating the steering piston in direct relationship to reciprocation of said master piston to rotate the steering wheel so that the frame follows the same turning arc as the vehicle; a third pair of hydraulic lines, one line of said third pair being connected at its opposed ends to one of the hydraulic lines of said first and second pairs of hydraulic lines, the other line of said third pair being connected at its opposed ends to the other lines of said first and second pairs of hydraulic lines; a valve in each line of said third pair of hydraulic lines, said valves being (1) openable to remove entrapped air from the hydraulic steering system and to replenish any loss of hydraulic fluid and (2) closeable to isolate the hydraulic steering circuit from the hydraulic circuit for raising and lowering the frame.

Claim 11

isolating said hydraulic steering system from the independent hydraulic source so that the slave piston is responsive to movement of the master piston.

Claim 12

isolating said hydraulic steering system from the independent hydraulic source so that the slave piston is responsive to movement of the master piston.

Claim 13

alternately flowing hydraulic fluid from said independent hydraulic circuit into and out of each said master-slave hydraulic conduits;

Claim 14

alternately flowing hydraulic fluid from said independent hydraulic circuit into and out of each said master-slave hydraulic conduits;

Claim 15

transferring entrapped air from said master-slave hydraulic system to said independent hydraulic circuit during step 3; and

Claim 16

transferring entrapped air from said master-slave hydraulic system to said independent hydraulic circuit during step 3; and

Claim 17

In a method of purging entrapped air from a master-slave hydraulic steering system on a semi-mounted plow, wherein said master-slave system includes a pair of hydraulic conduits interconnecting a slave cylinder steering a wheel on the plow and a master cylinder responsive to tractor turning movement, comprising the steps of:

Claim 18

In a method of purging entrapped air from a master-slave hydraulic steering system on a semi-mounted plow, wherein said master-slave system includes a pair of hydraulic conduits interconnecting a slave cylinder steering a wheel on the plow and a master cylinder responsive to tractor turning movement, comprising the steps of:

Claim 19

The method defined in claim 4, characterized by repeatedly performing step 3 to remove substantially all of the entrapped air from said master-slave hydraulic system.

Claim 20

flowing the entrapped air to said sump and removing it from the independent hydraulic circuit.

Claim 21

flowing the entrapped air to said sump and removing it from the independent hydraulic circuit.

Claim 22

In a method of adjusting the setting of a steering wheel on a semi-mounted plow, wherein said wheel is steered by a hydraulic system including a pair of hydraulic conduits interconnecting a slave cylinder and piston steering the wheel and a master cylinder and piston responsive to tractor turning movement, the steps of:

Claim 23

In a method of adjusting the setting of a steering wheel on a semi-mounted plow, wherein said wheel is steered by a hydraulic system including a pair of hydraulic conduits interconnecting a slave cylinder and piston steering the wheel and a master cylinder and piston responsive to tractor turning movement, the steps of: