Irrigation pipe gate

Claim 1

A GATE STRUCTURE FOR CONTROLLING FLOW THROUGH AN OPENING IN THE WALL OF A PIPE COMPRISING AN OPEN ENDED TUBULAR BODY HAVING AN INNER END INSERTABLE IN SAID OPENING AND AN OUTER END, THE INNER END OF SAID BODY HAVING SUBSTANTIALLY THE SAME OUTLINE AS SAID OPENING, SAID BODY HAVING AN EXTERNAL WALL SURFACE PORTION WHICH IS TAPERED IN THE DIRECTION AWAY FROM SAID INNER END TOWARD THE OUTER END, A RESILIENTLY RADIALLY EXPANSIBLE SLEEVE SURROUNDING SAID BODY BETWEEN SAID OUTER END AND SAID TAPERED PORTION AND HAVING A PROJECTED INSIDE CROSS SECTIONAL AREA, WHEN UNSTRESSED, LESS THAN THE PROJECTED OUTSIDE CROSS SECTIONAL AREA OF THE LARGEST END OF SAID TAPERED PORTION, THRUST MEANS INTERCONNECTING SAID SLEEVE AND BODY AND OPERABLE TO DISPLACE SAID SLEEVE RELATIVE SAID TAPERED PORTION TOWARD SAID INNER END AND TO RADIALLY EXPAND SAID SLEEVE AND TIGHTLY ENGAGE IT BETWEEN THE EDGE OF SAID OPENING AND SAID TAPERED PORTION, A CLOSURE PLATE COVERING THE INNER END OPENING OF SAID BODY, AND MEANS OPERABLE FROM SAID OUTER END OF SAID BODY TO PIVOT SAID CLOSURE PLATE BETWEEN COVERED AND UNCOVERED POSITIONS WITH RESPECT TO SAID INNER END OPENING.