Patent ID: 9222356
Filing Date: 2015-12-29
Classification: E21D

Abstract:
1. A drill bit exchange device for a shield tunneling machine in which a drill bit disposed at a front of a cutter head is exchanged during drilling from a working space formed in the cutter head, the drill bit exchange device comprising: a housing attached to the front of the cutter head, the housing having a tunneling aperture extending through a front surface of the housing wherein the drill bit may selectively extend through the tunneling aperture; a valve body disposed in a valve-housing chamber that is formed in the housing so as to communicate with the tunneling aperture, the valve body being pivotable about a pivot axis inclined at a predetermined angle with respect to an axis perpendicular to the front surface of the housing; a bit-housing hole that is formed in the valve body so as to selectively communicate with the tunneling aperture, the drill bit being detachably housed in the bit-housing hole; and an exchange seal recess formed in a front of the valve-housing chamber, the exchange seal recess being separated from the tunneling aperture by a predetermined angle with respect to the pivot axis, wherein the valve body is substantially cylindrical and includes a seal body that is formed along a front outer edge of the valve body so as to seal the tunneling aperture, an opening for the bit-housing hole formed on a part of the seal body, and a portion of the seal body around the opening being contoured to define a drilling recess, wherein a drilling end of the drill bit is received in the drilling recess, wherein the drill bit exchange device further comprises an exchange seal member that seals a clearance between the housing and the valve body around the exchange seal recess, and wherein the valve body is rotatable about the pivot axis so as to move the drill bit in the drilling recess to the exchange seal recess, thereby allowing the drill bit to be removed from the bit-housing hole and exchanged.