Power steering apparatus for towing

Claim 2

In combination: a. a vehicle power steering system comprising i. dirigible wheel means, ii. a horizontally swinging tow bar, iii. means connecting said tow bar and said wheel means for conjoint movement, iv. hydraulic motor means mechanically connected to said tow bar, v. a pump hydraulically connected to said motor means, vi. steering control valve means for selectively controlling the flow of fluid from said pump to said motor means, and b. selectively actuable hydraulic means connected to said system for permitting in one position thereof fluid forced by said motor means when said wheel means are steered by said tow bar and said pump is inactive to flow from one side of said motor means to the other side thereof and to and from a reservoir.

Claim 3

The combination of claim 1, wherein said hydraulic motor means comprises a cylinder and piston.

Claim 4

The combination of claim 2, said hydraulic motor means having a single piston rod extending from said piston and outwardly of said cylinder.

Claim 5

The combination of claim 1, wherein said hydraulic means comprises a valve, conduits connecting said valve with said hydraulic motor, and a conduit connecting said valve with said reservoir.

Claim 6

The combination of claim 4, said valve comprising means in a closed position thereof to prevent the flow of fluid in the conduits connected thereto and to said hydraulic motor.

Claim 7

The combination of claim 5, said last mentioned means in an open position thereof providing communication therethrough.

Claim 8

The combination of claim 5, said last mentioned means in an open position thereof providing restricted communication therethrough.

Claim 9

The combination of claim 4, said valve comprising a housing, a spool in said housing having a pair of spaced land means for closing communication between the interior of said housing and a said conduit connected to said hydraulic motor in the closed position of said valve.

Claim 10

The combination of claim 8, and restricted passage means in said spool providing restricted flow therethrough.

Claim 11

The combination of claim 8, wherein said pair of land means each closes communication between the interior of said housing and a said conduit connected to said hydraulic motor in the closed position of said valve.

Claim 12

A hydraulic power steering system for a vehicle to be operated in a power steering mode and in a towing mode, wherein dirigibly mounted steering wheels are connected by tie rods to a tow bar pivotal about a substantially vertical axis, a hydraulic steering motor is connected to said tow bar, and a motor-driven pump supplies hydraulic fluid to said hydraulic steering motor through a steering valve, the improvement comprising: a. valve means and conduit means, b. said conduit means hydraulically communicating said valve means with said steering motor for transmitting fluid between said valve means and said fluid motor upon movement of the latter in the towing mode, said conduit means further hydraulically communicating said valve means and a reservoir, c. said valve means comprising means in one position for blocking flow in said conduit means to said motor and in a second position for permitting flow therethrough to and from said steering motor and said reservoir.

Claim 13

A hydraulic power steering system for a vehicle to be operated in a power steering mode and in a towing mode, wherein dirigibly mounted steering wheels are connected by tie rods to a tow bar pivotal about a substantially vertical axis, a hydraulic steering motor is connected to said tow bar, and a motor-driven pump supplies hydraulic fluid to said hydraulic steering motor through a steering valve, the improvement comprising: a. valve means and conduit means, b. said conduit means hydraulically communicating said valve means with said steering motor for transmitting fluid between said valve means and said fluid motor upon movement of the latter in the towing mode, said conduit means further hydraulically communicating said valve means and a reservoir, c. said valve means comprising means in one position for blocking flow in said conduit means to said motor and in a second position for permitting flow therethrough to and from said steering motor and said reservoir.

Claim 14

The apparatus of claim 11, said valve means comprising a spool and spaced land means for blocking flow in said conduit means in the one position of said valve.

Claim 15

The apparatus of claim 12, said steering motor comprising a cylinder, a piston and a piston rod extending from one side thereof, a first said conduit communicating said valve housing with the side of said motor having said piston rod, and passage means extending through said land means for blocking flow in said first conduit, said passage Means providing communication through said land means for communicating both sides of said steering motor with said reservoir in the second position of said valve means.