Variable mechanical advantage shift lever

A shift lever assembly of the first class lever type for axially moving a shift rail of a synchronized positive clutch transmission of the type comprising synchronized positive clutches wherein the axial movement of said synchronized positive clutches from a fully disengaged axial position to a fully engaged axial position comprises a first segment of axial movement wherein the axially movable positive clutch member is moved into engagement with the blocking means and the frictional synchronizing clutches are initially engaged, a second segment of axial movement wherein the frictional synchronizing clutches are fully engaged to bring the positive clutch members into substantially synchronous rotation and a third segment of axial movement occurring after substantial synchronization of the positive clutch members wherein the axially movable clutch member moves past the blocking means into positive engagement with the other positive clutch member, said second segment of positive clutch member axial movement requiring a substantially higher axial force than is required during said first and third segments of axial movement of said positive clutch member, said assembly comprising;

• a substantially rigid section having a first end adapted for selective pivotal movement and a second end, said rigid section pivotably mounted at a fixed pivot point intermediate said first and second rigid section ends, said first rigid section end spaced from said pivot point by a fixed distance defining a first lever portion having a fixed lever length;
• a relatively resiliently deflectable section extending from said second rigid second end away from said pivot point, said resiliently deflectable section in the nondeflected position thereof engageable with a shift block member on said shift rail at a first contact point more distant from said pivot point than said rigid portion second end to define a second lever portion having a first effective lever length measured from said pivot point, said resiliently deflectable portion in the nondeflected position thereof preventing engagement of said shift block member with said rigid section second end, said resiliently deflectable portion resiliently deflectable to allow said rigid section second end to engage said shift block member at a second contact point closer to said pivot point than said first contact point to define a second lever portion having a second effective lever length shorter than said first effective lever length.

A shift lever system of the first class lever type for axially moving a shift rail of a synchronized positive clutch transmission of the type comprising synchronized positive clutch assemblies wherein the axial movement of said synchronzied positive clutches from a fully disengaged axial position to a fully engaged axial position to a fully engaged axial position comprises a first segment of axial movement wherein the axially movable positive clutch member is moved into engagement with the blocking means and the frictional synchronizing clutches are initially engaged, a second segment of axial movement wherein the frictional synchronizing clutches are fully engaged to bring the positive clutch members into substantially synchronous rotation and a third segment of axial movement occurring after substantial synchronization of the positive clutch members wherein the axially movable clutch member moved past the blocking means into positive engagement with the other positive clutch member, said second segment of positive clutch axial movement requiring a substantially higher axial force than required during said first and third segments of axial movement of said positive clutch member, said system comprising;

• a first class lever having a first fixed length lever portion extending from a selectively moved end to a substantially fixed pivot point and a second variable effective length lever portion engagable with a shift block member on said shift rail, said second lever portion engagable with said shift block member at a first and at a second contact point, said first point more distant from said pivot point than said second point, and
• resiliently deflectable means associated with one of said second lever portion and said shift block member for causing said second lever portion to resiliently engage said shift block member at said first point and preventing said second lever portion from engaging said shift block member at said second point when said resistance to axial movement is less than the axial force required in the second segment of axial movement of said positive clutch member, said resilient means resiliently deflectable to allow said second lever portion to solidly contact said shift block member at said second point when said resistance to axial movement is substantially equal to the axial force required in the second segment of axial movement of said positive clutch member.