Two gear-pairs with retaining teeth for alternating motion
Numbers give the tooth counts (96, 48, 192, 24, 8) of the gear train
In red chalk, this page works out a transmission built from two pairs of gears fitted with retaining teeth so as to yield an alternating (reciprocating) motion, as the e-Leo caption explains. The figures written beside the wheels—96, 48, 8, 192, 242, 24 and 2—are tooth counts that set the successive gear ratios of the train. Smaller sketches, drawn upside down, show a sphere, a cart and a horse. The chalk is faint, but the principal wheels and their annotations are legible.
On this page
Transmission of two gear-pairs with retaining teeth
Two meshing pairs of toothed wheels sit on a common frame; ratchet-like retaining teeth on the large wheels let the drive advance in one sense and lock in the other, converting continuous input into an alternating output. Weights or buckets are shown hanging from the lower shafts.
Tooth counts and gear ratios
The numbers 96, 48, 8, 192, 242, 24 and 2 are inscribed against the wheels. They record the count of teeth on each wheel, fixing the proportion between the turns of one shaft and the next through the train.