Frank Wardwell had at least 9 US patents. This Google Books link is to a 1915 article about Wardwell's metal cutting band saw sharpener, a much more sophisticated machine than Foley's saw filer at the time. I have scanned Wardwell's Catalog No. 48.
Some of Wardwell's filers used double-ended tapered saw files. I learned of the company from an eBay listing for files stamped "WARDWELL".
Here is a recent YouTube video of a Wardwell circular saw grinder running.