Rotary cutting apparatus

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 and drivingly connected to said motor;
• a distal rotary shaft that is coaxial with said axis, said distal rotary shaft being rotated about said axis by said proximal rotary shaft and axially movable relative to said proximal shaft;
• and
• a cylindrical housing coaxial with said axis, said cylindrical housing that rotatably houses said distal rotary shaft for no relative axial movement between said cylindrical housing 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 of said rotary shaft assembly;
• a second rack that is fixedly mounted on said body and has a column of teeth arranged along the axis opposite to said 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.

A rotary cutting apparatus comprising:

• a body;
• a motor mounted on said body;
• a rotary shaft assembly having an axis of rotation and a distal end adapted to hold a cutting tool coaxial with said axis, said rotary shaft assembly being mounted on said body such that said rotary shaft assembly is movable along 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 coaxial with said axis, said proximal rotary shaft being drivingly connected to said motor to be rotated about said axis and movable along said axis;
• a distal rotary shaft that is coaxial with said proximal rotary shaft and adapted to hold said cutting tool, said distal rotary shaft being rotated about said axis by said proximal rotary shaft and axially movable relative to said proximal rotary shaft;
• and
• a cylindrical housing that rotatably houses said distal rotary shaft or no relative axial movement between said cylindrical housing 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,
• wherein rotation of said pinion causes axial movement of said rotary shaft assembly in its entirety between said retracted position and said extended position.

A rotary cutting apparatus comprising:

• a base for fastening said rotary cutting apparatus at a desired position;
• and,
• a body that is mounted on said base such that said body is movable along an axis relative to said base,
• wherein said body comprises:
• a motor that is mounted on said body;
• a rotary shaft assembly that rotates around said axis and is 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 coaxial with said axis, said proximal rotary shaft being drivingly connected to said motor to be rotated about said axis;
• a distal rotary shaft that is coaxial with said proximal rotary shaft and adapted to hold said cutting tool, said distal rotary shaft being rotated about said axis by said proximal rotary shaft and axially movable relative to said proximal rotary shaft;
• and
• a cylindrical housing that rotatably houses said distal rotary shaft for no relative axial movement between the cylindrical housing 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 of said rotary shaft assembly;
• a second rack that is fixedly mounted on said base 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 base and said pinion and further relative axial movement between the pinion and said cylindrical housing.