I acquired this from the estate of a Rolls Royce owner and ephemera collector who was a long time member of The Rolls Royce Owners Club, he must have been one of the most advanced collectors of Rolls Royce in the entire world. His estate had an incredibly large collection.  

William Tapley – Creator of the Original Decelerometer

Tapley Instrumentation, which Bowmonk purchased in 2006, can trace its roots back to a Mr William Tapley, creator of the Tapley Meter – the original and iconic decelerometer. Tapley designed many measuring devices, with his first instrument being created in the 1900’s, for which he was granted patent number 21,517 in 1910 in Great Britain.

One of Tapley’s products was the Tapley Gradient Meter.

What we now recognise as the iconic Tapley Meter, used to measure a vehicle’s deceleration, soon followed, with Tapley being granted a patent in the USA in 1929.

Tapley was a constant innovator, and a later USA patent application, granted in 1938, reveals improvements to the design of his instruments to overcome magnetic interference from nearby ironwork. The patent application also refers to Tapley’s original 1910 instrument.

So synonymous was the Tapley Meter with brake testing that in the USA the act of testing a car’s brakes was often referred to as a “Tapley Test”.