Found this maybe you’ve seen it already. There’s a few photos there too.
Practical Machinist.
https://www.practicalmachinist.com/vb/antique-machinery-and-history/ot-crawler-tractors-196276/index16.html
believe this to be an “Orolo” track unit, or a copy of one. “Roadless – The Story of Roadless Traction from Tracks to Tractors” by Stuart Gibbard has this to say about the “Orolo” track unit.
“One of Roadless‘s first and most commercially viable ventures was the introduction of the Orolo track units. Originally designed for the British Admiralty to transport a 6 in. naval gun over soft ground, the Orolo unit consisted of a self-contained bogie with rigid girder tracks running around two or three rollers. The track was designed to be self-locking so that it would form a predetermined radius to give it the same performance as an extremely large diameter wheel with very low rolling resistance.
The Orolo units were available in several different sizes, and could be used in place of the wheel in a variety of applications, including bullock and mule wagons for Africa, India and South America, log carriers and lifeboat carriages – and the Roadless drawing books even show details of an Excelsior washing machine so equipped in 1932, but for what purpose is not known.
When the Orolo unit was first conceived, a scaled-down version was tested on Philip Johnson‘s garden wheelbarrow. So successful was this unit, that Roadless decided to put the tracked wheelbarrow into production. A couple of hundred were made towards the end of 1927, and it became a popular addition to the company‘s early product line. At the other end of the scale were the D8 Oro1o track units, introduced in 1929 and capable of carrying 12 tons per pair. The company eventually built units during the Second World War which would carry 20 tons on each track-bogie. The Orolo track units remained in production until well into the 1960s.”
I can’t help but notice that at least two of the gentlemen at the John Allen & Sons (Oxford) Ltd. stand at the Royal Show are wearing spats.
The pub model(?)…
…and the export model(?). (Manufactured in 1929 by Khasia Sillimanite Company in India).
You can see one of the original patent documents for this type of track <here>.
G2 Orolo brought out in 1930 with rubber jointed tracks.
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