Herringbone Gear

The double helical planetary train shown by Gary was being made by a charity and sold at the Midland expo a few years ago. I bought one, and it was fasinating, UNTIL I left it on the dashboard one day and it melted into a solid lump ! This brought home one of the short comings of some types of 3D printing materials. Noel

If you want to see double helical (Herringbone ) gears in operation, go the The WaterWorks Museum in Hereford and look atb trhe big National gas engine.

The next dayb thastbthe engine will be operating is Sunday August 13th

Howard

The brine pump at the Lion Salt Works has double herringbone gears, probably cast, but the engine is not well displayed, difficult to get a close look

The single or double ('herringbone' helical gear was a natural progression from 'Stepped Gears' : a set of relatively narrow spur wheels bolted together to make the full width, with each rotated slightly past its neighbour.

At the other end of the scale was the 'Knuckle Tooth' or 'Hollows and Rounds'. These profiles are simply semicircles meeting each other on their diameters. Simple and cheap to make, they were used only for slow, rough work like manual winches, because the teeth do not roll on each other but slide with a lot of friction and alternating velocities.

Herringbone gears are also used on the Anderton boat lift in Cheshire, you can see them (just) here.

Links to http://s0.geograph.org.uk/geophotos/05/00/89/5008920_d21b9ad9.jpg

Rob

Not now they're not. When originally built it had a humongous hydraulic ram under each caisson, but they went rusty, so were replaced with the gears and counterweights as per Rob's link. However the new structure holding that lot up is now itself past its best, so at the latest rebuild it went back to long hydraulic ram under the caisson. My daughter-in-law's father has a summer job driving and maintain it. They counterweight gubbins is still in place, but no ropes (or weights)

Thanks Duncan, didn't realise that

Rob

Another gem from my brother, who is currently jollying around the country:

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http://www.watchetconservationsociety.co.uk/pdfs/StoatesMillInterpretationBoard.pdf

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MichaelG.

Edited By Michael Gilligan on 13/07/2023 09:23:10