Gear 11 is keyed to shaft 1. Gears 4, 5 and 6 can be shifted along square guide a of shaft 2. Gears 12, 8, 9 and 10 are keyed to intermediate shaft 3. Three different transmission ratios can be obtained by shift ing gear 4 into engagement with gear 8, or gear 5 with gear 9, or gear 6 with gear 10. Thus i₁₂=(z₁₂/z₁₁)(z₄/z₈), i₁₂=(z₁₂/z₁₁)(z₅/z₉) and i₁₂=(z₁₂/z₁₁)(z₆/z₁₀). Tumbler gear arm 14 turns freely about the axis of shaft 3 and carries tumbler gear 7, which is keyed to intermediate shaft 13 and in constant engagement with gear 10. By turning handle b of arm 14, tumbler gear 7 can be brought into engagement with gear 6. Then the transmission ratio is i₁₂=-(z₁₂/z₁₁)(z₆/z₁₀) so that shaft 2 is reversed. When gear 4 is shifted to the left so that its clutch member engages that of gear 11, the transmission ratio is i₁₂=1. When driving shaft 1 rotates, driven shaft 2 can have any of four forward speeds, or one reverse speed.
$2858$CxG,SR$