Patent ID: 7001117
Filing Date: 2006-02-21
Classification: B23B,B23Q,B25H,Y10T

Abstract:
1. A rotary cutting apparatus comprising: a body; a motor mounted on said body; a rotary shaft assembly having an axis and adapted to hold a cutting tool coaxial with said axis; and, a feed mechanism for moving said cutting tool along said axis between an extended position and a retracted position, wherein said rotary shaft assembly comprises: a proximal rotary shaft that is mounted coaxially with said axis on said body for rotation about said axis, said proximal rotary shaft being drivingly connected to said motor; an intermediate rotary shaft that is connected coaxially and telescopically to said proximal rotary shaft for axial movement between them but for no relative rotation therebetween, whereby said intermediate rotary shaft rotates together with said proximal rotary shaft; a distal rotary shaft that is connected coaxially and telescopically to said intermediate rotary shaft for axial movement between them but no relative rotation therebetween, whereby said distal rotary shaft rotates together with said intermediate rotary shaft; and, a cylindrical housing that rotatably houses said distal rotary shaft for no relative axial movement between said cylindrical house and said distal rotary shaft such that said cylindrical housing moves axially together with said distal rotary shaft, and further wherein said feed mechanism comprises: a first rack that is fixedly mounted on said cylindrical housing and has a column of teeth arranged along said axis; a second rack that is fixedly mounted on said body and has a column of teeth arranged along said axis opposite to the teeth of said first rack; and a pinion that is positioned in engagement with the teeth of both said first and second racks, said pinion being axially movable relative to each of said first and second racks, whereby rotation of said pinion causes relative axial movement between said body and said pinion and further relative axial movement between the pinion and said cylindrical housing.