Back in the 1940s and into the 50s the tractor manufacturers rarely manufactured the blades or loaders themselves and these were made by companies like Baker, Heil, Garwood, La Plant, Bucyrus Erie and Drott in The States and Bray, Blaw-Knox and others here in the UK.
I believe the first Drott loaders were fitted to Allis Chalmers and later to Cletrac and International.
Drott developed the "BULLCLAM" which was the forerunner of the "4 in 1 bucket" which gave them a considerable advantage over the competition.
Though this could not be used for loading trucks it was very useful for picking up and carrying aggregates etc. on site and
they soon designed a loader to hang it on.
The 4 in1 Bucket was patented and it was years before the competition were able to produce a copy so several other loader manufacturers fitted buckets with the Drott name on them till comparatively recently.
In the States Drott produced a range of other equipment including hydraulic excavators up to at least 3 cu yards, rubber ducks, a range of telescopic cranes and industrial handling equipment.