Watts sun and planner gear.

Just out of curiosity, has Watt's sun and planet mechanism ever been used for anything other than its original purpose, of doubling the speed of a beam engine crankshaft?

I thought it was invented as an answer to the problem of using a crank which had already been patented by a.n. other who’s name escapes me at the moment.

But I stand to be corrected on this.

Edited By V8Eng on 25/05/2020 20:18:14

I did not think it doubled up the speed as the two gears were the same size. Epicyclic gear often has 2:1 and was used on some 4-stroke engines with a steam engine type eccentric rather than usual 2:1 spur gears.and cam

I've made a couple, one for the Robinson X-type which actually used them and another for an engine of my own design.

Ploughing engines also had epicyclic gears in the coiling gear.

Edited By JasonB on 25/05/2020 20:23:36

Dragging out old memories James Pickard rings a bell - I too will be happy to be corrected if I have misremembered

Nick

Sun and planet doubles the flywheel speed, honest. Think of it as follows:

consider the gear attached to the con rod to be loose
turn the crank one rev, the loose gear will roll around the gear on the crankshaft and do one turn around the crankpin
in reality it can't turn, it's fastened to the con rod, so rotate it back around the crankpin one turn to where t should be.
the crankshaft will do another rev, so it has now done 2 revs

As others say it was a dodge to get round patent, but driving the flywheel at double speed made it have the same effect as quadrupling the flywheel mass, as the energy stored increases as speed squared

And I don't reckon Jason's gears are epicyclic anyway, there is no sun gear.

Edited By duncan webster on 25/05/2020 20:52:02

There's a nice illustration of the gear in Wikipedia, using Meccano. For a 1:1 gear ratio, the sun and flywheel rotate twice for every circuit of the planet.

I was very pleased with myself, when I managed a Meccano version of the gear, having just see it in the Science Museum when I was twelve. I was just wondering if it had been used on treadle mahines or hand operated water pumps, or something. It seems too good to have had a single use.

Maurice.

Seeing this posting I thought I would post some pictures of odd gear sets that I photographed in a Renault Museum in paris

Edited By Nimble on 26/05/2020 03:05:29

Edited By Nimble on 26/05/2020 03:06:46

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