That term is regularly used but it is Might be somewhat inappropriate, since it is a brand name for a different style electro-mechanical horn (ah oo gah horn).
From what I've read since finding that site I linked above, a Klaxon horn is any horn that uses a motor-driven toothed wheel that ratchets against a metal stud attached to a diaphragm.
Also... "Even after the Klaxon design was replaced" with the electromagnetic design "the term 'Klaxon' was still used to mean an automotive horn." ...not sure how long this went on for tho.
