Patent ID: 8403916

Claim:
A medical instrument for use on a patient, comprising: a housing forming an external body of said instrument for manipulation by a user, said housing having a proximal end and a distal end, a tool mount at said distal end of said housing, said tool mount defining a mounting bore having a proximal end and a distal end; a motor having a drive shaft rotatable about a drive axis; a drive magnet fixed to said drive shaft of said motor such that rotation of said drive shaft rotates said drive magnet about said drive axis, wherein said motor, said drive shaft and said drive magnet are hermetically sealed within said housing; and at least one replaceable tool assembly detachably coupled relative to said drive magnet at said mounting bore of said tool mount, said mounting bore located outside said hermetic seal, said tool assembly formed as a separable unit from said housing and said tool mount, said tool assembly including, a tool holder releasably received in a proximal direction through said distal end of said mounting bore during coupling of said tool holder to said tool mount, and in a distal direction out of said distal end of said mounting bore during decoupling of said tool holder from said tool mount, an elongate tool shaft having a tool shaft axis and proximal and distal ends, said tool shaft extending through said tool holder and rotatable about the tool shaft axis, a tool magnet having a tool magnet axis about which said tool magnet rotates and a diameter, said tool magnet fixed to said proximal end of said tool shaft and movable relative to said tool holder, said tool magnet magnetized with opposite polarity on opposite sides of said diameter, and a medical tool for interacting with a patient, said medical tool fixed to said distal end of said tool shaft such that said tool magnet axis, said tool shaft and said medical tool are coaxially arranged along said tool shaft axis, wherein rotation of said drive magnet by said motor induces, via magnetic forces between said drive magnet and said tool magnet, movement of said tool, and when said drive magnet is rotated, said tool holder remains stationary within said mounting bore of said tool mount.