Hobbs 'Mechamatic' Gearbox

[autogyro]

....... most interesting !

presumably planetary box losses are only competitive with layshaft box losses in direct drive ?
(all-indirect layshaft boxes are indirect only once whatever the ratio, (eg) how are 3-8 speed planetaries ?)

(I know that's not the main point of this activity)

planetaries were established in bicycles 110 years ago, and were much more efficient than since planet bearing balls were deleted
planetaries were established in motorcycles 100 years ago
(but the motoring world chose layshaft boxes)

ALL the gears in a layshaft box excluding perhaps the reverse idler, are thrashing around oil the whole time the vehicle is in motion.
In direct gear a planetary set rotates as one 'smooth' unit.
In direct drive a planetary set only needs lube for its support bearings.
If there were no need for oil for operating clutches etc the support bearings could be sealed and the gear teeth would only need spray lube when under load in each gear, not when locked stationary.
You could even air cool the geartrain internaly and in F1 use the airflow for DF benefits.
Layshaft 'burst' loads are offset which is weak, they are fully balanced in a planetary set.
This means the gear caseing will be a far better design and fewer bearings will be needed.
Like my developments the Hobbs box made use of these and other benefits, its problem was the rubber bags used to apply the clutches and its limitation to low input torque figures.
The motoring world did not completely choose layshaft gearboxes only the European part because of the lack of investment. There are plenty of planetary gearboxes in American automatics.
Both ways were way below the potential for planetary geartrains, even 30 years ago.

[lorimor]

I worked at the Mechamatic plant from Dec. 1963 to Feb. 1967. Originally under the banner of Gresham & Craven, then Westinghouse Hobbs, followed by Eaton Yale & Towne & finally Eaton ENV transmissions. The Mechamatic project was already in limbo when i started. Ford had got cold feet over quality issues, each gearbox required fine tuning on a dynamometer after assly. at our Norfolk st. factory, before delivery. Ford took delivery of the first batch, stripped them down, shuffled the components & re assembled the gearboxes, with obvious consequences.

A 'Flowline' (an early attempt at fully automated production) had been designed & installed by an outside contractor, to fully machine the complex gearbox casings. This was the era before microchips & it never functioned acceptably. Much litigation was flying around & the number of units installed in the plant's garage (commissioned by individuals & Ford dealerships) dwindled to a trickle. By 1965 the dream was over. It was heart breaking to witness tons of gearbox components being weighed in for scrap. The plant was turned around to manufacture gearbox components for the major motor manufactures of the day &, later on, Eaton truck gearbox components.

A good concept, ahead of material & manufacturing capabilities of the day. I suspect it was somewhat under developed when it was put into production. Never the smoothest at gear changing, it was affectionately known as the 'Jerkmatic'. My abiding memory of Norfolk st. stems from a fact finding mission to the Alvis factory in Coventry. I accompanied a works director in one of the company's 'pool' cars, a 1500cc Cortina fitted with a Hobbs Gearbox. A high mileage 'clunker' that was in serious need of some TLC. The aggressive driving style of my chauffeur ensured that every up change of that pre motorway journey felt like a kick up the derriere from a crazed mechanical mule, & his later attempt at extricating the Cortina from a 'boxed in' Alvis car park dilemma, hamstrung by those savage clutches, was classic comedy. Happy days.

[01j]

Hello autogyro,

Do you know where I can find a Hobbs MecahMatic clutch? I've got a car that came with one of these from the factory but about half the cutch is missing. Thanks, 01j.

[Tornado220]

The AP box is/was very different from the modern 'clutch' boxes you mention.
It had brake bands as well as clutches (the original clutch plates and bands were phospher bronze and steel) with seperate servos which were easy to fit different feed piping to, there was also much more room to play with. The geartrain was/is a bevel epicyclic not the conventional spur and was much stronger more compact amd a better planetary concept all together. More costly to make though. The geartrain ran in engine oil with the engine.
There are competition conversions for modern auto gearboxes but modern units now have up to 8 gears anyway and the gains in rpm gaps would be minor. The torque converters are now more intigrated with the powertrain operation with lock up operation and the like. The modified Mini had no fluid link (the torque converter was not used) but used a conventional clutch. This can be achieved on any gearbox and many clutchflite units exist but the work involved in modern units would be great.

Hi Autogyro, I am interested in talking with you about your ideas for the automatic AP unit