Step-by-step irrigator

In a step-by-step irrigator, of the type comprising a column, a propelling tube rotatable relative to said column, a torsional brake between said column and said tube, said propelling tube including a laterally extending portion for directing a jet of water along an outward path relative to said column, an impulse arm assembly having a nose, deflector means on said nose, means mounting said impulse arm assembly on said propelling tube for periodic swinging movement between a first position in which a stop on said arm engages a stop on said tube and said deflector means at the nose is in the path of the water jet, and a second position in which the deflector means is spaced from the water jet path, said deflector means being of the type in which the rotational thrust exerted on the tube increases with increased water pressure, and return means for returning the arm toward said first position, a rapid return deflector disposed at the end of a lever lying below the laterally extending portion of the propelling tube, which rises into and lowers below the jet under the action of a mechanism for reversing the rotational direction of motion of the tube, the improvements comprising, in combination, means for automatically adjusting the braking of the rotation of the rotatable tube to increase the braking in response to increased pressure of the water at the propelling tube, and means for adjusting the period of swing of the swinging mobile nose, said deflector means comprising double acting deflector means for swinging the arm in response to impingement thereon by the water jet to move said arm toward said second position, and to arrest said swing during the return movement toward said first position when the stop on said arm is close to colliding with the stop on said propelling tube.