English Tech/Engineering Mechanics / Mech Engineering crankless press

What can possibly M/B (written this way, with a slash) mean in these terms:

M/B Location Device Ass'y
M/B Stopper Ass'y
M/B Drive Ass'y
M/B Cover Ass'y
M/B In L/S Ass'y
M/B In Stopper
M/B Clamp @ Lifting Ass'y
M/B Rail Ass'y

The text is an operator's manual for a crankless press (metal forming) in Korean English full of non-typical abbreviations, acronyms, and most unusual exppresssions you could ever imagine. I managed to decipher what they meant in most cases but am sick of guessing.
I will not be able to ask the Korean company since the translation was ordered by a Polish customer to an agency who commissioned it to me. The manual does not provide any clue as to what M/B might perform because it is used in a list of drawings which are not included themselves.

I will greatly appreciate any smart prompt.