Allcock sold two versions of jointed floats in the late Sixties. I believe the idea was that lying flat on the surface, the upper section would sit bolt upright before going under with a bite.
One was called the Tru-Bite
A bit on them here:
viewtopic.php?f=10&t=24162&hilit=hinged+float
TBH those illustrated look better made then those by Allcock!
There were some lovely fluted floats sold by Tom Watson about that time too, I think they were made by the shop foreman who gets a mention in Tom's catalogues. Tricky painting those black and white stripes on those ones.