DIN 1481 heavy-duty spring pin
A spring pin is a hollow cylinder which has a longitudinal slit from one end to the other. It has a diameter greater than the nominal diameter of the circular slot where it is to be fitted. When the spring pin is introduced in the hole it is compressed and retained due to the elastic force which it exerts on the walls of the slot. The longitudinal slit narrows but stays slightly open.
HRc 43÷49 (HV 422-560)