Hammer Brand Imperial Toothpick Gray Pearl & Green 1950s switchblade Book knife

Vintage Hammer Brand toothpick style switchblade made in Providence, RI in the 1950s by the Imperial Knife Co. It was designated the model JM-90-PBC and measures 4.25 inches closed and 7 3/16 inches open and has STEEL liners, button and safety. The clip blade is about 91% full with dark patina some scratches, & some spotting and has loss from sharpening/use. It is marked Hammer Brand USA on the front tang with a picture of an arm holding a hammer and the back is marked PAT NOS 2170537 over 2281782. The scales are hollow metal wrapped in Gray pearl w green streaks celluloid with some shrinkage, but nice overall. The knife works well with the short blade tip below the liners closed, opens fully and locks open well with about 1/8 inch movement each way at the tip. Rattles if shaken when open. Safety works. G condition. This is an actual knife that will be featured in the upcoming book Antique American Switchblades 2 and comes with a laminated COA (certificate of authenticity) signed by the author.