Hammer Brand Imperial Toothpick Candystripe 1950s vintage switchblade 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 9/16 inches open and has brass liners and steel button and safety. The blade is nearly full about 97% and shiny with some scratches, & some spotting and a couple of pit spots on the front. It's marked Hammer Brand USA on the front with a picture of an arm holding a hammer. The back is marked PAT NOS 2170537 over 2281782. The scales are hollow metal wrapped in Candystripe celluloid with a little spotting underneath and light handling scuffs. The knife works well with blade tip seating deep and centered closed, opens fully and appears to lock open, but doesn't actually lock. Blade stays in open position just fine, but you can close it without pushing the button. Does not rattle if shaken when open. Safety does not work. VG condition.