This video shows several spanning devices, which were common in the Holy Roman Empire during the middle ages.
Please note:
All data in the table refers to the shown devices. If the ratio of the windlass or cranequin are increased, they will of course be able to pull even higher weights - but again at the price of the shooting cadence.
To answer some other questions:
Goat foot levers did not appear until the late 15th century and were not common in the HRE.
The wooden push lever was also not used until the end of the 15th century - primarily for sporting crossbows.
In addition to the large winch shown, large spanning stands or large lever spanning devices were also used for stationary use.
For further information about medieval crossbows, spanning divices and other stuff visit: www.historiavivens1300.at/
0:00 Intro
1:38 Hook spanning belt
2:41 Belt and pulley systems
3:45 Windlass
4:49 Cranequin
6:22 Large windlass
7:33 Comparison
8:37 Summary