Gear trains, a column-lifting rig, and a beam-loading rule
Wheels, lantern-pinions and crank shafts; oxen raising columns; the mechanics of loading a beam on centre.
The sheet is crowded with drawings of geared mechanisms: wheels turning on square axles, an idle wheel, lantern-pinions and crank shafts whose directions of rotation Leonardo works out letter by letter. Other notes concern a rig using oxen to raise and load columns and a rule that a beam loaded exactly on the centre line of its thickness will not bend. Several columns of figures accompany the drawings.
On this page
Three-wheel train: driven axle, idler and follower
Wheel a turns together with its axle, which is square. Wheel b has no axle of its own but runs idle. Wheel c is turned by wheel b.
Directions of rotation in a threaded gear system
If wheel d turns to the left, wheels a and c, threaded together, turn to the right in their upper part, so the large wheel b turns to the left. The instrument above works the same way from behind, making e turn right, f left and g right.
Rig to raise and load columns, worked by oxen
An apparatus for raising and loading columns is sketched and annotated with teams of oxen and figures (1, 11, 5). It uses animal power to hoist and place heavy shafts on site.
A beam loaded on its centre line does not bend
If a beam is loaded along its straight line so that the centre of the weight lies on the same line as the centre of the beam's whole thickness, it will never be bent, its base being of equal resistance. If the weight's centre is off-centre, the beam's head leans toward it.
Columns of figures
A block of numerals is set out in the lower right corner of the sheet, read with the leaf turned about. They appear to be tallies or computations tied to the mechanisms and loads above.