Motorized surgical handpiece

A motorized surgical handpiece for driving a surgical tool to perform a cutting operation on anatomical tissue at a surgical site, said handpiece comprising

• a housing enclosing an interior and including a forward end wall having an opening therethrough and a rearward end wall having a passage therethrough in longitudinal alignment with said opening;
• a motor disposed in said interior between said forward end wall and said rearward end wall;
• an output shaft disposed in said interior for being driven in rotation by said motor, said output shaft having a longitudinal bore extending entirely therethrough for receiving a shank of a surgical tool to be rotatably driven by said output shaft to cut anatomical tissue at a surgical site, a forward end portion extending through said opening to a forward shaft end disposed exteriorly of said housing, and a rearward end portion extending to a rearward shaft end disposed in said interior, said bore being in longitudinal alignment with said passage;
• a forward labyrinth seal comprising a forward labyrinth seal stator component formed by said forward end wall, a forward labyrinth seal rotor component attached on said forward end portion of said output shaft for rotation in said opening with there being a labyrinthine clearance between said forward labyrinth seal rotor component and said forward labyrinth seal stator component;
• a rearward labyrinth seal comprising a rearward labyrinth seal stator component disposed in said interior and having an opening therethrough longitudinally aligned with said passage, a rearward labyrinth seal rotor component attached on said rearward end portion of said output shaft for rotation in said opening of said rearward labyrinth seal stator component with there being a labyrinthine clearance between said rearward labyrinth seal rotor component and said rearward labyrinth seal stator component;
• a forward air supply passage in said forward labyrinth seal stator component for supplying pressurized air to said clearance of said forward labyrinth seal to flow in a direction away from said front end of said motor;
• a rearward air supply passage in said rearward labyrinth seal stator component for supplying pressurized air to said clearance of said rearward labyrinth seal to flow in a direction away from said back end of said motor;
• a tool retention device in said housing to the rear of said rearward labyrinth seal for releasably lockingly engaging the shank of the surgical tool;
• and
• a continuous lumen extending longitudinally through said housing, said lumen comprising said bore and said passage through said rearward end wall.

A motorized surgical handpiece for driving a surgical tool to perform a cutting operation on anatomical tissue at a surgical site, said handpiece comprising

• a housing comprising a body having a central longitudinal axis, an interior, a forward end closed by a forward end wall, and an open rearward end, and an end cap secured to said rearward end to enclose said interior, said end cap having a rearward end wall and a forward extension extending forwardly from said rearward end wall into said interior, said forward end wall having an opening therethrough coaxial with said central longitudinal axis establishing communication between said interior and the environment exterior to said housing, said end cap having an opening therethrough establishing communication between said interior and the environment exterior to said housing, said opening through said end cap including a bore extending from the environment exterior to said housing through said rearward end wall into said forward extension coaxial with said central longitudinal axis and a window extending from said bore to said interior;
• a motor disposed in said interior and having a front end and a back end, said front end being adjacent said forward end wall;
• an output shaft in said interior coaxial with said central longitudinal axis for being rotatably driven by said motor, said output shaft having an internal surface defining a through bore through said output shaft coaxial with said central longitudinal axis for receiving a shank of a surgical tool therethrough with a close fit, a forward end portion extending forwardly beyond said front end of said motor through said opening in said forward end wall to a forward shaft end located exteriorly of said housing, a rearward end portion extending rearwardly beyond said back end of said motor to a rearward shaft end located in said interior, said forward end portion having a configuration adjacent said forward shaft end for direct driving engagement with the shank of the surgical tool by which the surgical tool is rotatably driven by said output shaft to perform a cutting operation on anatomical tissue at a surgical site;
• a forward labyrinth seal comprising a forward labyrinth seal stator component formed by said forward end wall, a forward labyrinth seal rotor component disposed on said forward end portion of said output shaft for rotation with said output shaft in said opening in said forward end wall with there being a labyrinthine clearance between said forward labyrinth seal rotor component and said forward labyrinth seal stator component, said forward labyrinth seal rotor component having a through passage receiving said forward end portion to extend coaxially entirely through said through passage, said clearance being in communication with said interior and with the environment exterior to said housing;
• a rearward labyrinth seal comprising a rearward labyrinth seal stator component disposed in said interior adjacent said back end of said motor, said rearward labyrinth seal stator component having an opening therethrough coaxial with said central longitudinal axis, and a rearward labyrinth seal rotor component disposed on said rearward end portion of said output shaft for rotation with said output shaft in said opening of said rearward labyrinth seal stator component with there being a labyrinthine clearance between said rearward labyrinth seal rotor component and said rearward labyrinth seal stator component, said rearward labyrinth seal rotor component having a through passage receiving said rearward end portion to extend coaxially into said through passage of said rearward labyrinth seal rotor component, said clearance of said rearward labyrinth seal being in communication with said opening through said end cap;
• an air supply conduit supported to extend exteriorly along said housing for receiving pressurized air from a pressurized air source;
• a forward air supply passage in said forward labyrinth seal stator component extending from said clearance of said forward labyrinth seal to said air supply conduit to supply pressurized air from said air supply conduit to said clearance of said forward labyrinth seal during the cutting operation and during cleaning of said handpiece to prevent the entry of foreign substances into said interior from the environment exterior to said handpiece;
• a rearward air supply passage in said rearward labyrinth seal stator component extending from said clearance of said rearward labyrinth seal to said air supply conduit to supply pressurized air from said air supply conduit to said clearance of said rearward labyrinth seal during the cutting operation and during cleaning of said handpiece to prevent the entry of foreign substances into said interior from the environment exterior to said handpiece;
• a tool retention device comprising a slide mounted for sliding movement in said window along a diametric axis perpendicular to said central longitudinal axis, a bearing assembly carried by said slide including a bearing having an internal bearing surface defining a bearing passage through said bearing in communication with said through bore of said output shaft and said bore of said end cap for receiving the shank of the surgical tool therethrough, a spring mechanism biasing said slide in said window in an offset direction along said diametric axis where said internal bearing surface is inwardly offset from said internal surface of said output shaft in said offset direction to prevent longitudinal movement of the shank of the surgical tool and thereby lock the surgical tool to said handpiece, and an operating member disposed exteriorly of said housing for moving said slide along said diametric axis in a direction opposite said offset direction to align said internal bearing surface with said internal surface of said output shaft to permit longitudinal movement of the shank of the surgical tool and thereby release the surgical tool for removal from said handpiece;
• and
• a continuous lumen through said housing comprising said through bore of said output shaft, said bearing passage and said bore of said end cap, said lumen providing communication entirely through said housing when the surgical tool is removed from said handpiece for insertion of a brush entirely through said lumen for cleaning.