Hello Peter,
If you mean the forward-facing dropouts for the Tour de France, Juy 51, etc., they aren't listed in the 1952 Brown Brothers catalogue, but they are in the 1956 catalogue. I don't have any catyalogues in between the two dates. The fitting instructions in the 1950 Fonteyn catalogue don't mention ends with an integral gear hanger; they only refer to the fixing plate. This tends to confirm that they may not have been available, in England at least, until after 1952, but that they certainly were by 1956.
They were no longer listed in the 1960 Brown Bros. catalogue.
I'm afraid I can't get any more specific.
Neil Foddering Weymouth, England
>From: "Peter Brown" <peterg.brown@ntlworld.com>
>To: <classicrendezvous@bikelist.org>
>Subject: [CR]Dating Simplex vertical dropouts
>Date: Fri, 28 Apr 2006 10:02:20 +0100
>
>Is anyone able to tell me please when Simplex vertical dropouts with
>integral gear hanger were introduced, and possibly also when they went out
>of production.
>
>
>
>Peter Brown, Lincolnshire, England