A system is proposed for transmitting energy and/or data between a vehicle body and a removable part, a first core half having a pin and a pin ring which extend into a second core half to thus improve an inductive coupling. The first and second core halves are elements of an inductive transformer, and in each case have windings to transmit the energy and data, respectively. So that the pin does not protrude when a movable part is removed from a vehicle, in a further development, a ring is provided with bore holes and an annular spring which ensure that all primary-side transformer parts terminate flush with the vehicle floor. The improved inductive coupling makes it possible for the core halves to be made predominantly of an iron material.