[motto]

I'm not familiar with the German 'coffee mill' so cannot compare features, design or function.
On these jacks the square upper section is the oil reservoir and also contains the pump. A square shaft sticks out one side of this section and the handle which is about three feet long slips onto this for pump operation. Below this shaft is the valve for lowering the jack.

David

Correction:- the jack I have is 15 ton not 22.5 as the one in the photograph.