Post a photo on the "Vintage" section of the Forum, and someone will be able to tell you everything about your bike. Sachs made hubs, with their three-speed hub being fairly common thirty years ago.
If you a wondering about the quality of your old bike, a good clue is the design of the "drop outs"...the part of the fork that the hub fits into. The best old bikes had thick, beefy, strong drop-outs (Schwinn being the best example). The department store bikes had thin, flimsy drop-outs, made by simply "crushing" the tip of the fork. The old-time Schwinn one speed frames and forks were so tough that the pioneer mountain bike builders were using Schwinn frames that were twenty, thirty, and forty years old.