This patent is for a much more mature and refined design than Alex Shuttleworth and William Hill’s 1931 patent of the TriVelox system (UK Patent # 382104). The crude plate shoving the freewheel block from side to side has been replaced by a precision engineered sliding pin moved by a rod inside a hollow axle, much like the mechanism for moving the clutch in a Sturmey-Archer three speed hub gear.
The inventors are listed as Valentine Page and the Triumph Company Limited. Val Page was the chief designer at Triumph at the time, and is one of the heroic figures in the tragicomedy that is the story of the British motorcycle industry. Mere mention of the words ‘Ariel Red Hunter’ or ‘BSA Gold Star’ is enough to bring a tear to the misty eyes of a certain genus of motorcycle geek. Poor souls, they should get out more (unlike us derailleur nerds). There is no mention of the word ‘TriVelox’ here - the company involved is clearly Triumph, with TriVelox existing only as a Triumph brand.