Greetings Karen. A very interesting story indeed. I tried doing some research a few years ago on your grandfather and his inventions. The man was apparently quite creative, and was awarded patents for improvements to everything from reclining chairs to parachutes.
Here are my (rather dry) notes about the Klüglein Nail and Tack Puller, both early and later versions:
Early version: 6-1/2” pliers with parrot jaws designed for gripping carpet or upholstery tack heads, with a protrusion off one jaw that acts as a fulcrum for prying. Coil spring between handles. Nickel plated steel. No markings. Patent 1,891,164 issued to Theobald Klüglein of New York, N.Y. on December 13, 1932
Later version: Same arrangement as early version, but an entirely different forging. One-half inch longer, with checkering added to handles, and a hole between the plier jaws. No longer has a coil spring between handles. Stamped TH. KLUGLEIN – VALLEY STREAM N.Y. around pivot on one side, and U.S. PAT. NO. 1,891,164 on the other. MADE IN GERMANY stamped on one handle, FORGED STEEL on inner surfaces of both handles, and KLUGLEIN on outer surfaces.