Press Button Knife Co INVINCIBLE antique switchblade knife

Vintage Press Button Knife Co INVINCIBLE model switchblade made in Walden, NY sometime between 1900 and 1923. The knife measures 4 7/8 inches closed and 8 1/2 inches open with jigged bone scales and steel liners. The blade is marked PRESS BUTTON KNIFE CO WALDEN, NY on the tang and the backside is stamped US PAT 470605. The blade has been used and sharpened over the years and is about 90% full and has been cleaned to a bright shiny finish. The picked bone scales are in very good condition with no cracks.  The knife functions well with the blade tip even with the liners closed, opens strong when button pressed and locks open, but loose and rattles if shaken when open. About 3/16" up and down and 1/8" side to side. This is a nice working example of a 100+ year old American made switchblade. VG condition.