Thanks
The device comes from the 12th century. Apparently thereīs a counterweighted version called a Sambucca (probably due to the amount of spirits anyone had to drink before actually getting into the bucket)
As far as I can tell, the front bucket can be lowered to ground level, then someone would climb in, the arm would be raised and they would swop to the other immobile bucket then the process would be repeated to fill the front bucket. That, ot two people would go up in the front bucket and one would swop over.
With the front arm fully raised the device would be trundeled up to the wall, the front bucket would then be lowered so the archer/crossbowman could shoot down onto the wall or into any courtyards etc behind. The Archer/crossbowman in the rear bucket would give covering fire whilst the front one reloaded and visa versa.
Alone this device would probably be pretty ineffective but if there were a couple or more of them to increase the rate of fire along with a tower with other archers and such devices as catapults etc to keep up a hail of missiles then I suppose it could be effective in overcoming the relative protection of the parapets.
I was going to add a ladder to the fixed bucket. Logically that would have been the quickest way to man the device but as I havent seen any pics with a ladder, not that there are that many pics anyway, I decided against.
I reckon anyone would have had to be completely crazy to go up in the fixed bucket and start staring mad to go in the front one..what if the rope broke!!!