An adapter assembly (200) to selectively interconnect a surgical charging unit (300) that is configured to perform a function and a surgical device (100) that is configured to drive the charging unit, including the charging unit, at least , an axially translatable drive member (374), and the surgical device including at least three rotatable cylindrical drive bodies (118, 120, 122), the adapter assembly comprising: a housing (202) configured and adapted to the operative connection with the surgical device； an outer tube (206) having a proximal end portion supported by the housing and a distal end portion configured and adapted for operative connection to the loading unit； a plurality of force / rotation transmission / conversion assemblies (240, 250, 260) arranged inside the housing and outer tube, wherein each of the force / rotation transmission / conversion assemblies includes: an element rotation receiving proximal (212, 214, 216) that can be connected to a respective one of the at least three rotary drive shafts of the surgical device； and a distal force transmission element (248, 252, 266), each of the distal force transmission elements being connected to each of the proximal rotation receiving elements, respectively； wherein at least one distal force transmission element (248, 252, 266) can be connected to at least the only axially translatable drive element of the load unit, in which one rotation at least one of the proximal rotation receiving elements becomes an axial translation of the respective distal force transmission element； wherein at least one of the plurality of force transmission / rotation / rotation assemblies converts and transmits a rotation of the respective one of the at least three rotary drive shafts of the surgical device into at least one axial translation, of the only axially movable drive element of the load unit； characterized in that each of the proximal rotation receiving elements is arranged in a common plane with each other.Un co
