I am having problems attaching a photo. That said, I've looked carefully at the machine and it is "S Davis and Co" The S has been rubbed off but can still be made out.
I didn't think it was an American machine but would like to know how old it is.
It has a vibrating shuttle and looks very like a Singer 27k.
Somewhere on the web recently I saw that S Davis and co re-badged German machines but this one clearly says Made in England on both the front and back.