Patent ID: 8616078

Claim:
A multistage transmission in which a plurality of driving gears (m) and a plurality of driven gears (n) are supported on mutually parallel gear shafts in a constantly meshing state for every speed, one of the driving gears (m) and the driven gears (n) are fixed to one of the gear shaft, and engagement means is provided for each of the other gears, the engagement means being operative to cause an engaging projection ( 31 ) formed on an inside periphery of each of the other gears to engage a radially movable engaging member (R) provided on the other gear shaft ( 12 ) for each of the other gears, due to radially outward protrusion of the engaging member (R), in a manner to fix each of the other gears to the other gear shaft for speed shift: wherein said engaging projection ( 31 ) is formed on an annular inward protrusion ( 30 C) on the inside periphery of each of the other gears (n); an annular plate member ( 35 ) is provided which is positioned close to, and turnably relative to a side surface of the inward protrusion ( 30 C) having the engaging projection ( 31 ) of each of the other gears (n); and a return spring ( 38 ) is interposed between each of the other gears (n) and the annular plate member ( 35 ) to elastically maintain a predetermined relative position thereof; and wherein the annular plate member ( 35 ) is provided on an inside periphery thereof with an abutment projection ( 36 ) having inclined surfaces for abutment with the engaging member (R), said return spring ( 38 ) being operative to cause a portion of the abutment projection ( 36 ) at least other than the inclined surfaces to overlap the engaging projection ( 31 ) as viewed in an axial direction; and each of the inclined surfaces of the abutment projection ( 36 ) comprises a bottom-side inclined surface ( 36 pb ) having an inclination angle allowing engagement with the engaging member (R), and a top-side inclined surface ( 36 ps ) having an inclination angle which does not allow engagement with the engaging member (R) but allows sliding movement of the engaging member (R).