Side wheel roll leveling device

In a rollable sidewheel irrigating device of the type having an axle horizontally disposed and attached to two vertically disposed circular supports, an irrigation conduit connected to a source of irrigating fluid and extending perpendicularly from said axle, a gravity-biased sprinkler conduit rotatably connected to said irrigation conduit, and a sprinkler head connected to said sprinkler conduit and biased by the force of gravity to a position perpendicular with the ground, the improvement comprising:

• fluid pressure activated means, disposed between said irrigation and sprinkler conduits, for permitting rotative movement of said sprinkler conduit relative to said irrigation conduit as said device is rolled into position prior to the entry of irrigating fluid into said device, and for locking said sprinkler conduit relative to said irrigation conduit for preventing said rotative movement when irrigating fluid of sufficient pressure enters said device, thereby maintaining said perpendicular orientation of said sprinkler head relative to the ground, wherein said fluid pressure activated means comprises:
• (a) means for permitting sufficiently free rotative movement of said sprinkler conduit prior to the entry of irrigating fluid to the device such that the force of gravity on the sprinkler conduit and sprinkler head is alone sufficient to maintain said perpendicular orientation of said head, whereby an additional counterweight on the sprinkler conduit or head is not required;
• and
• (b) means for locking said sprinkler conduit relative to said irrigation conduit after irrigating fluid enters the device with a locking force sufficiently large such that the locking force by itself resists any forces arising from operation of the sprinkler head tending to rotate the sprinkler conduit relative to the irrigation conduit.