Two screw-lifting devices with numbered ratios
Vertical threaded screws and racks studied for mechanical advantage
Two carefully drawn lifting mechanisms stand side by side, each built around a vertical threaded screw working within a framed rack, mounted on a base plank. A small funnel-like body is sketched at the lower left, and faint construction lines and further untranscribed notes underlie the page. The two devices are annotated with short number sequences (1–1–2/3 and 6–18) that record the proportions of the gearing.
On this page
First threaded-screw device
The first mechanism is a vertical screw enclosed in a rectangular frame with two boxed racks, standing on a plank base. It is annotated with the number sequence 1 – 1 – 2/3, recording the proportions of its parts.
Second device with 6–18 ratio
The second mechanism, likewise a vertical screw in a frame with a lever arm at its foot, is marked with the numbers 6 – 18. The figures set out the ratio governing the lifting action.