If you've ever done home canning, then you know how difficult it can be to remove the lid on a jar fresh out of the pantry. This little tool was designed to address exactly that problem. The original U.S. patent 2,059,736 was issued in 1936 to Joseph A. Manarik of Chicago, Illinois. Given that my example is stamped "A Stewart Product", I can only assume that it was manufactured by Bertram H. Stewart of New York, New York, who was awarded a 1946 design patent for his own can opener, and then a 1951 patent (2,570,881) for a "plier type friction cap remover." (Around the same time, he also received US design patents for a ball pen point and a toy airplane engine, the latter assigned to the Streamline Motor Corp. of New York.) Online, I have been able to find only two products made by the Stewart firm, the other being a cork screw. So, it would seem that the company was highly specialized. Anyway, I look forward to trying the device on my next jar of chili sauce.
Above package images from bullworks.net. I'm not sure how the tool was supposed to work on ketchup bottles, unless there was a time before they didn't come with screw tops.