Hi, Tom & CR---
Humber used that signature twin-bladed fork design, called the "Duplex," for many years, mainly on roadsters (some with rod brakes) for which they were primarily known. I believe the Duplex fork was in use at least as early as the '20s and kept into the '50s on roadster and "sports" models.
Here is a photo of a 1954 Humber Royal roadster, with the Duplex forks---
http://www.mvvcc.org.uk/
By the early to mid-fifties their lightweight models (really "sports" machines) such as the Beeston Tourist and the Clipper (both of which were popular with the Cyclists' Touring Club members) were using standard single-blade forks of Reynolds 531.
The claimed mechanical advantages of the Duplex forks (again, primarily for roadsters) were ruggedness and comfort. They certainly are rugged and also eye-catching. Whether or not they deliver additional comfort...well, you'd have to ask an owner. In addition to the Duplex fork, Humber pioneered various cross-frame designs, again primarily for roadsters and "sports" machines.
Humber Cycles, "The Aristocrat of all Bicycles," had a rich history as one of the grand old firms, dating back to 1869 as Humber & Company Limited, founded by Thomas Humber at Beeston, Nottinghamshire. They were later acquired by Joseph Horton of Birmingham and moved their works to Wolverhampton. Around 1900 new works were built at Stoke in Coventry and production moved there.
They were also famous for their motorcars.
They were one of the first firms gobbled up by Raleigh, in 1932, and eventually production was moved to Nottingham. They continued manufacturing under Raleigh ownership until the '70s.
I saw the auction listing which you site and, though it is an interesting frame, I am not convinced that it is a genuine "lightweight," as it is more likely from a roadster or "sports" machine, the latter being used more for touring and all around cycling rather than pure racing. You'll see very few (if any) Humbers appearing in the racing annals of the golden lightweight era of the '30s through '50s. The Duplex-forked Humbers are quite nice and, of course, interesting, and easily found in Britain (a couple on Ebay UK right now), but not so often here in the States, where they are prized by gentlemen and gentlelady cyclists who ride in the Lake Pepin 3-Speed Tour.
There is what I am told an excellent book on the history of Humber Cycles, which I occasionally see on Ebay UK.
Hope this bit o' information helps.
Cheerio,
Peter Jourdain
Whitewater, Wisconsin USA
> From: Thomas Adams <thomasthomasa@yahoo.com>
\r?\n> Subject: [CR] Humber frame with 4 barrelled fork
\r?\n> To: classicrendezvous@bikelist.org
\r?\n> Date: Tuesday, April 6, 2010, 10:06 PM
\r?\n> Here's one I haven't seen before, a
\r?\n> Humber frame with a different fork design. Nothing for
\r?\n> Humber on the CR GB pages. Archives are down, so I
\r?\n> apologize if these were discussed before. How long were
\r?\n> these on the market? Did they work, or give any
\r?\n> advantage?
\r?\n>
\r?\n> http://ebay.com/
\r?\n>
\r?\n> or ebay item: 160420791805
\r?\n>
\r?\n>
\r?\n> Tom Adams
\r?\n> Manhattan, KS, USA