Patent ID: 7431402
Filing Date: 2008-10-07
Classification: E21C,E21D

Abstract:
1. A rock boring device comprising: a housing; a shaft mounted within said housing for rotation about a longitudinal shaft rotation axis, said shaft having a driven section and a mounting section, said mounting section including a mounting axis, parallel to and spaced from said shaft rotation axis; rotational drive means connected to said driven section of said shaft, said drive means providing rotational drive to said shaft; and a disc cutter mounted on said mounting section of said shaft and axially aligned with said mounting axis such that rotation of said shaft induces a lateral oscillation of the disc cutter about the shaft rotation axis; a bearing disposed between said disc cutter and said mounting section to provide free axial rotation of the disc cutter with respect to the shaft about the mounting axis; wherein said cutting disc includes a circumferential workface engaging periphery; an inertial reaction mass connected to said housing, said mass being relatively large in proportion to the disc cutter, thereby to stabilize the disc cutter and provide inertial absorption of peak impact forces of the cutter on the workface and effect rock cutting generally radially from said disc cutter periphery.