Can anyone tell me the correct name for the fastener that's commonly
used to hold the wheels onto an axle of kids toys, or push chairs. It
looks like a domed metal cap with a captive star washer inside that
pushes onto the end of the axle and the "teeth" on the star washer
grip the end of the axle to stop the cap from coming off.

If I can find the proper name I might then be able to google to find a
source for them.

Thanks
David.