Parts...
Unfortunately, it is not likely that you will be able to find parts for your machine but may be able to find a complete unit. They do pop up on auction websites on occasion - but are by few and far between. The E720 Super Straight Suction Vacuum was the company's first model with production beginning in 1919. The scans below are from a 1928 company issued catalog (which is very thick and cannot be disassembled - thus the poor images), and was the only model offered until the introduction of the 125B Hand Vacuum, followed by the Motor Driven Brush/Ball Bearing Cleaner #'s E580, E585, E585B. The E720 must have gone out of production by the time my 1937 catalog was issued because the straight suction cleaner was now #E435 and was identical to the 580 series except lacking a brush roll.
As far as other names for the company's uprights - I have only seen one example where they did not use the "standard" trade mark, that being Whirlwind. The company's tank cleaner offerings were an entirely different story as they made machines for different department stores, sewing centers, and vacuum shops. President, Super Chief, Super Dynamic, Modern Housekeeping(I think), Whirlwind (oddly enough), Atlas, even Regina.
Tank and canister models made by the company to be sold through "their" dealers were: RotoVersa, Clean Air Cleaner, Jet99, Landers, (a lower-tier model), and the the "Univ....." Super Dynamic (I believe the name is - I have only seen one example of this machine - similar to a Royal or Saniway)...
The 720 has a very unique handle attachment system whereby when the handle is assembled to the motor unit the electrical connection is automatically made eliminating a separate plug or other electrical connection.. A brilliant engineering feat, and very much so overbuilt to last. The two machines I have incorporating this handle are still very much intact and show no signs of wear. I have a E720 and a Whirlwind E610 - both employ this method.
The E720 and other machines offered by the company did have an alloy (bronze I think) sleeve bearings and they did seize up quite readily. However, they can be "massaged" apart, and reconditioned to original condition and operate very well. I have done this several times - if they previous owner of your machine didn't destroy the unit, you may be able to make necessary restorations using the parts you have.
See the scans below - notice that attachments were available, also see a link to a recent auction - (this brand does show up from time to time - and rest assured - I have twenty examples representing the entire line offered by the company, so it's not likely I will be bidding on any that do....).
http://www.ebay.com/itm/VINTAGE-UNI...D&orig_cvip=true&rt=nc&_trksid=p2047675.l2557
