Synchronized gearboxes having at least one non-synchronized speed

Claim 1

In a gearbox comprising a case and the following elements mounted in the case: a first shaft, a second shaft, at least one set of synchronized gears comprising a first gear rotatably mounted on said first shaft and a second gear integral with said second shaft, a first movable gear engaging means combined with said first gear and comprising a synchronizer for synchronizing the rotation of said first gear with the rotation of said first shaft and coupling means for coupling said first gear with said first shaft to rotate with said first shaft, first shifting means combined with said first gear engaging means for shifting said first gear engaging means between a neutral position, a first position in which first position said synchronizer is rendered operative and a second position in which second position said coupling means is rendered operative, said second position being beyond said first position relative to said neutral position, an unsynchronized second set of gears comprising a third gear integral with said first shaft and a fourth gear integral with said second shaft, a second gear engaging means cooperative with said second set of gears and comprising a rotatable gear pinion capable of being shifted to an operative position of engagement between said third and fourth gears, and second shifting means combined with said second gear engaging means for shifting said gear pinion to said operative position; the improvement comprising intermediate means movably mounted on said first shifting means, selector means capable of cooperating simultaneously with said second shifting means and said intermediate means, releasable means for fixing said intermediate means to said first shifting means, said selector means being capable of shifting said first shifting means through the agency of said intermediate means a sufficient extent to cause said first gear engaging means to move from said neutral to said first position substantially before said selector means has shifted said gear pinion to said operative position through the agency of said second shifting means, and means for releasing said releasable means when said first gear engaging means have reached said first position and thereby precluding further movement of said first gear engaging means while said selector means continues to shift said gear pinion into said operative position through the agency of said second shifting means, said selector means being capable of cooperating solely with said first shifting means to the exclusion of said intermedite means and said second shifting means when it is desired to engage said first set of gears.