Hi, All.
A quick piece of research on these stands show that they were patented by David Raitt Robertson, and cast at Port Brae Machine Works, Kirkcaldy, Scotland, sometime between 1892 and at least 1896.I found the ‘improved’ patent from 1896, GB29676, (hopefully attached in .pdf below ) but was unable to find the original patent GB8683 of 1892. This appears to be the patent number cast into the bottom of the stands.
Type 1 and 2 picture Credits: gingganggoollie
There appear to be at least three different types of stand, two types for the 1892 patent, and one for the 1896 patent.
The two 1892 type stands vary in the size of wheel they accept. Due to the manufacturing dates, I think this may be for the large ‘ordinary’, and smaller ‘safety’ bicycle wheels.
The 1896 type stand has two of the feet modified to take rotatable Duck heads (!) to hold handlebars if the bike is turned upside down to work on.
Type 3 picture Credits: not known
Incidentally, this stand shows evidence of having been 'Bronzed', like
@Velo-dream 's. The Type 1 and 2 above both seem to have been aluminium painted, probably at a later stage in their lives.
Best Regards
Adrian