Time to continue our exploration of ways of getting power to the wheels with the minimum of operator input without actually using a conventional automatic.
Meet the Hobbs Mecha-matic.
Except that you can’t as I haven’t been able to find a usable picture of either gearbox or its inventor, Howard Hobbs.
Meet his son David instead.
Hobbs senior came up with the Mecha-matic in 1946 having been working on designs for a “gearless” transmission without success.
The Mecha-matic was an epicyclic unit with four forward gears. Just like an ordinary automatic so far but instead of a torque converter it used an automatic clutch for stopping and starting. Gearchanges were carried out by hydraulic brakes and clutches operated by bags (no, me neither) and a secondary clutch locked the unit to give top gear.
Power losses were less than a torque converter ‘box but without the cushioning effect of a hydraulic coupling it was difficult to get the unit to change smoothly and pretty much impossible to keep it changing smoothly as wear took place.
Nonetheless Hobbs got a contract from Ford to supply up to 500 boxes a day for the Mk2 Cortina so he sold 50% of the business to Westinghouse to raise the funds needed to build a factory for the purpose. The factory was duly built but on receiving a batch of pre production transmissions Ford found that the quality wasn’t acceptable and cancelled the order, resulting in plenty of work for each side’s lawyers.
There’s an interesting discussion right here of the issues involved.
There’s a test report just here which is remarkable for being written entirely from Hobbs’ point of view and suggests that the unit nicknamed “jerkomatic” in its day was a marvellous thing.
The Mecha-matic had its moment of glory though. Howard Hobbs’ son David campaigned a Lotus Elite fitted with the gearbox to great effect and found that the fast gearchanges were well worth the jerks. His trick for fast launches was to hold 5,000 rpm in neutral and apply first gear, which did the starting clutch no long term good at all but made for a very quick getaway.
The idea didn’t go away though. Mercedes sell various AMG models with an epicyclic automatic linked to a multi plate automatic clutch. Very little is truly new in this world.