EXCAVATION HEAD OF DIAMETRICALLY EXPANDING EXCAVATOR FOR CONSTRUCTING FOUNDATION PILE

摘要

PROBLEM TO BE SOLVED: To provide an excavation head of an excavator for constructing a foundation pile, superior in excavation performance, capable of securing the quality of a foot protection expanded bulb, and capable of suppressing an earth removal quantity when pulling up, in the excavator in the form of gradually diametrically expanding an expanding blade by a spline structure.;SOLUTION: This excavation head 1 has a hollow driving shaft 2 and an excavation shaft 3 relatively movably stored in the axial direction inside its shaft. The expanding blade 4 joined by a pin to the driving shaft 2 side is expanded and contracted via a diametrically expanding plate 5 on the excavation shaft 3 side by using these relative movements. A spline is formed of a U-shaped key way 6 on the inner surface side of the driving shaft 2 and a key 7 on the outside surface side of the excavation shaft 3. The key way 6 is formed in a U shape out of a guide part 6a in the vertical direction, a first locking lock part 6b in which the key 7 is engaged in the circumferential direction when normally rotating the driving shaft 2 in the diametrically contracted state of the expanding blade 4, and a second locking lock part 6c in which the key 7 is engaged in the peripheral direction when normally rotating the driving shaft the a diametrically expanding state of the expanding blade 4.;COPYRIGHT: (C)2008,JPO&INPIT