Dental handpiece reduction gear

In a dental handpiece comprising a rear socket and a front socket removably connected to said rear socket, a removable modular reduction gear comprising two easily interfitting sections, namely:

• a first section removably received in said rear socket and comprising a first bearing, a central input shaft rotatably supported by said bearing, means for retaining said input shaft against movement longitudinally of said bearing, means at the rear end of said shaft for rotationally driving said shaft in either direction of rotation, and a sun pinion on the front end of said input shaft,
• a second section removably received in said front socket and comprising a second bearing abutting a shoulder in said front socket, a central output shaft rotatably supported by said second bearing, a coupling member on the forward end of said output shaft and abutting the front end of said second bearing, a planet gear carrier fixed on the rear end of said output shaft and abutting the rear end of said second bearing, whereby said output shaft is retained by said coupling member and said planet gear carrier against movement longitudinally of said second bearing, and a plurality of freely rotatable planet gears carried by said planet gear carrier, and
• an intermediate sleeve received in said front socket and having an internal ring gear opposite ends of which are abutted by said first and second bearings to hold said sleeve against rotary and axial movement in position for engagement of said internal ring gear by said planet pinions which mesh with said internal ring gear and with said sun pinion on said input shaft when said front socket is connected to said rear socket with said first and second sections of said modular reduction gear interfitting,
• said first and second sections being removable from said rear socket and front socket respectively when said front socket is disconnected from said rear socket.