Ben - Davleco Industries got their start during WW2, as with many Australian manufacturers. The company was started by a Mr W. G. Davies. The company kept a low profile in the 1940's and I can't even find when the company was originally registered. The first mention I found was Davleco advertising for a requirement or a lathe with a 15' bed in 1949.
They got a Govt Supply contract for "jigs" in 1951, but their roller product line didn't receive much advertising until the early 1950's.
They were a favourite supplier to councils, and produced a lot of equipment over the decades from the mid-1940's to the late 1970's, until poor economic conditions for manufacturing, such as high inflation, large wage and salary increases, a major reduction in import tariffs, and strong competition saw Davleco fall into liquidation.
They merged with Braemar Industries in 1974, but the merger was obviously a major blunder, as Braemar-Davleco then started losing lots of money, with over $500,000 loss reported in 1976.
I'm not sure what happened to the company. I understand they were claiming that they had organised a takeover by Vulcan Industries around 1977, when they were being put into liquidation by Tricontinental Corporation, but I can find nothing that came from that claim. It appears that Davleco's assets were sold, but the company shell survived.
Davleco was suspended from the Melbourne Stock Exchange in 1979 for failing to supply annual company records, but it must have been re-instated some time later, as I found a notice that Davleco had changed its name to Victor Petroleum in 1980, and the company was going into mining and oil and gas. Victor Petroleum was delisted in 1987, so it looks like they achieved little.
In the late 1960's, they were going great guns, even arranging sales to the U.S. Of course, in the late 1960's and early 1970's, the USD$/AUD$ exchange rate was quite favourable.
https://nla.gov.au/nla.obj-96433429...bj-964428937#page/n14/mode/1up/search/Davleco
Davleco even went into a Joint Venture in the late 1960's with an American gent by the name of Mr W. J. Weller, who was formerly sales engineer for the George J Meyer Manufacturing company.
Davleco and Weller formed Meyer-Davleco Pty Ltd, a subsidiary company of Davleco and they talked about Meyer-Davleco producing bottling equipment. The subsidiary operation seems to have folded with no indication they ever produced anything.
https://nla.gov.au/nla.obj-96532914...bj-965348688#page/n16/mode/1up/search/Davleco
The Morawa Historical Society can provide you with a copy of the operating instructions for the 72" Davleco roller. See under the "Rollers" heading.
http://members.iinet.net.au/~caladenia_new@westnet.com.au/miscman.html
There's a full list of the Davleco Roller range on Page 31 of this Feb/March 1975 Hire & Rental News publication.
https://www.hireandrentalnews.com.au/wp-content/uploads/magazine-archives/no1/025 Hire - Feb-Mar 1975.pdf
Roller Parts Australia can supply belts and a centrifugal clutch assembly, but these parts are quite likely to be readily available from the likes of bearing suppliers or industrial product suppliers.
https://www.rollerparts.com.au/
Most rollers are pretty simple and basic, the areas to keep an eye on are the rubber isolator pads, and the vibratory mechanism bearings. The vibratory action is hard on the drive bearings, and they must be well greased.
Otherwise, belts and pulleys and pulley bearings, and engine maintenance are the regular things to keep up.
Here's a bloke who has a neat old ride-on Davleco in good operating condition.