Patent ID: 7597024

Claim:
A gear-shifting device for a manual transmission in which an operational force applied at a change-lever for a shift operation is transmitted selectively to actuate a synchro-sleeve for a gear shift; wherein: said gear-shifting device comprises a shift arm, which is rotatable in correspondence to said shift operation of said change-lever, and a shift piece, which is in contact with said shift arm and is capable of shifting in response to said rotation of said shift arm; said shift arm having heteromorphous cams at a contacting part thereof, wherein said cams are in contact with said shift piece and wherein said heteromorphous cams have at least two different cam profiles which contact a same surface of said shift piece; and while said shift arm is rotating in correspondence to said shift operation, a distance between said contacting part and a rotational axis of said shift arm varies to change a leverage effective between said change-lever and said contacting part.