high pants monkey
All major components
Clockwise from top centre: outer planet cage with external freewheel attached; cover for pawls; hub shell; three-prong dog clutch, with ball race ring to left and clutch housing above; axle with push-rod (top) and cross-pin in situ - you can see two of the four splines on the axle that engage with the slots in the base of the clutch housing. The cross-pin passes through an eye at one end of a spring-loaded indicator rod; when the push-rod is operated, the clutch housing slides along the axle. The default (gear lever full forward, wire slack) locks both sun pinions to give direct drive. The next position - lever in the middle - frees one sun pinion but holds the other, to give the lower gear, while the final position - lever hard back - reverses this to give the high gear.
All major components
Clockwise from top centre: outer planet cage with external freewheel attached; cover for pawls; hub shell; three-prong dog clutch, with ball race ring to left and clutch housing above; axle with push-rod (top) and cross-pin in situ - you can see two of the four splines on the axle that engage with the slots in the base of the clutch housing. The cross-pin passes through an eye at one end of a spring-loaded indicator rod; when the push-rod is operated, the clutch housing slides along the axle. The default (gear lever full forward, wire slack) locks both sun pinions to give direct drive. The next position - lever in the middle - frees one sun pinion but holds the other, to give the lower gear, while the final position - lever hard back - reverses this to give the high gear.