Turbine insert for the head of a dental turbine elbow

A turbine insert for insertion into a head-housing of a turbine elbow for dental use comprising:

• a rotatable axle having two ends and a plurality turbine blades disposed thereon, one of the axle-ends being adapted to receive a dental tool;
• a threaded cap attachable to the head-housing;
• support means for receiving said rotatable axle, the other of the axle-ends being rotatably supported in said threaded cap through said support means;
• and a protective sleeve surrounding said turbine blades, formed with an opening for the passage of compressed air for driving the turbine, and at least partially surrounding and rotatably supporting the dental-tool receiving axle-end through said support means, said threaded cap, said rotatable axle and said support means for said axle being combined into a single unit before insertion into said head housing;
• said threaded cap and said protective sleeve being formed with ring-shaped front ends facing and abutting each other, respectively;
• said support means including first and second supports and said threaded cap being formed with a wall surrounding said axle, and further comprising first and second elastic abutment elements disposed between said first support and said wall, and between said second support and said protective sleeve, respectively;
• each of said abutment elements including an O-shaped ring of elastic material;
• the ring-shaped front ends of said threaded cap and said protective sleeve being formed with inwardly facing ring-shaped projections, respectively, the inwardly facing ring-shaped projection of said protective sleeve being spaced from the ring-shaped front end thereof, said O-shaped rings respectively abutting said inwardly facing ring-shaped projections axially in a direction facing said turbine blades;
• said threaded cap being formed with a second inwardly facing ring-shaped projection spaced from the inwardly facing ring-shaped projection, one of said O-shaped rings abutting against said projection in a direction facing away from said turbine blades;
• said threaded cap including a floor forming said second projection;
• each of said supports having an end facing said turbine blades and being formed with an outwardly facing projection spaced from the turbine-blade facing-end thereof, said O-shaped rings axially abutting said outwardly facing projections, respectively, in a direction facing away from said turbine blades;
• said first and second supports including first and second ball bearing supports having first and second outer rings, respectively, each of said outwardly facing projections being disposed on one of said outer rings, respectively;
• said head-housing including a wall formed with a guidance recess, said turbine elbow including a compressed air supply formed with an orifice, said protective sleeve being formed with an outwardly projecting guidance lip for engaging said guidance recess for forcibly alignment of the protective-sleeve openings with the orifice of said compressed air supply.