Not sure of proper name ... But I am referring the the segmented round spring washer thingy's that are used to retain shafts. Often used of pushchairs, etc.
As per this pic:
Nearest description I can think of is 'Push-on shaft retainer'
Simple Q ... is there a particular knack of method to remove these without breaking them ?
I usually end up trying to pry up the 'gripping tongues' and ease out with a screwdriver, but often end up damaging the darn things.
They obvioulsy work by having a hole smaller than shaft diameter ... so assume trying to use a set of 3 leg pullers on outer edge, would either kink the outside edge or turn thing inside out and probably snap it.