Bank's cash machine staff (4)
I believe the answer is:
cane
'staff' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for cane that I've seen before include "Stem of palm" , "Beat; sugar producer" , "Slender stem of bamboo etc" , "e.g. Bamboo stem" , "Hollow stem of wood" .)