The first *diesel* engine that I know of which used them (UK market) was the awful Ford York, particularly awful because the timing drive was unreliable, which must have been circa 1970, they had been used for timing drives in petrol engines for some years prior to that but my guess is still within the 1960's for timing drives.
The book was published in 1954, the solution to the problem was around the late
The book shows loads of applications including a Homelite chain saw, a Skil wood planer, sewing machine, drill press. typewriter (Royal) cheque cancelling machine (Cummins Business Machine Co) and also many larger applications including a 7" wide belt from a 128hp motor, so the belts were pretty much developed by the mid 1950's.
The book is "Timing Belt Drive Engineering Handbook", by Richard Y. Case who is given as the inventor of the belt, McGraw-Hill, 1954.
US Patents 2507852 and 2397312
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