You can search patents at http://www.google.com/patents and when you search for Sarah Levitas, there are two results.
The first result is for Patent No. 842,893, patented Feb. 5, 1907 to S. Levitas for "Suspensory Device for Garters, &c.," Application filed Apr. 4, 1905.
The initial result page is an OCR'ed version of the patent (Optical Character Recognition), so it's not a 100% accurate transcription of the patent, but you can click on a button for the PDF of the patent, and here it is, with Sarah Levitas' signature on the first page:
So, although only Emanuel is listed as Garter Manufacturer in census records, it looks like his wife had something to do with his success in his business.