Patent ID: 8573089

Claim:
A speed change operation apparatus for a stepless speed changer device, configured to increase a rotational output in response to increase in rotational displacement of a trunnion shaft from a neutral position to an operational position, the speed change operation apparatus comprising: an operational tool whose operational displacement causes rotational displacement of a trunnion shaft between a neutral position and an operational position; a pivotal body operably coupled with the trunnion shaft to be pivotally displaced in response to an operational displacement of said operational tool; a positioning body operably coupled with said pivotal body to be pivotally displaced in response to pivotal displacement of said pivotal body, wherein said pivotal body and said positioning body are operably coupled with each other via a cam mechanism, comprising a cam and a cam follower, so as to cause a pivotal displacement of the positioning body in response to a pivotal displacement of said pivotal body; a main urging mechanism for providing an urging force to said pivotal body via said positioning body, said urging force returning said pivotal body from the operational position to the neutral position; and an auxiliary urging mechanism for providing an auxiliary urging force to said pivotal body, said auxiliary urging force returning said pivotal body from the operational position to the neutral position; wherein a main moment of force provided to the trunnion shaft by the main urging mechanism at the neutral position of the trunnion shaft is stronger than a main moment of force provided to the trunnion shaft by the main urging mechanism at the operational position of the trunnion shaft; and wherein an auxiliary moment of force provided to the trunnion shaft by the auxiliary urging mechanism at the neutral position of the trunnion shaft is weaker than an auxiliary moment of force provided to the trunnion shaft by the auxiliary urging mechanism at the operational position of the trunnion shaft.