CHEMICAL DISCHARGE PORT CHANGE-OVER DEVICE FOR STIRRING HEAD

摘要

PROBLEM TO BE SOLVED: To provide a chemical discharge port change-over device for a stirring head to automatically change discharge of chemical from a specified discharge port in accordance with vertical motion of a drilling rod. SOLUTION: A head main body 1 of a stirring head has a chemical supply passage 6 in the inside axial direction and has an upper part discharge port 7 branched from this chemical supply passage and to open to a side surface of the head main body and a lower part discharge port to open to a lower end of the head main body, and a change-over mechanism 10 to change a passage over to the upper part discharge port or to the lower part discharge port is furnished on a branch part of the chemical supply passage on the stirring head connected to a lower end of a drilling rod and to stir a drilling ground. Additionally, this change-over mechanism is furnished with an elevating member 17 externally fitted on the head main body free to integrally rotate with it and provided free to slide in the vertical direction and a change-over valve member 11 to open the lower part discharge port by closing the upper part discharge port at the time when this elevating member relatively rises against the head main body and to close the lower part discharge port by opening the upper part discharge port at the time when it drops, and the elevating member is devised to elevate by earth pressure in accordance with elevation of the head main body.