Press Button Knife Co #1000 INVINCIBLE antique switchblade knife w lanyard

Vintage Press Button Knife Co INVINCIBLE model automatic knife made in Walden, NY sometime between 1892 and 1923. The knife measures 4 7/8 inches closed and 8 9/16 inches open with steel liners and lanyard ring with nickel silver bolsters & button. The clip blade is 97% full, or better and has been Beautifully cleaned and the tang is stamped PRESS BUTTON KNIFE CO WALDEN, NY ,but is hard to read because the tang was pitted before cleaning. The backside is stamped US PAT 470605. The picked bone scales are in very good condition with no cracks. The knife functions well with the blade tip well below the liners closed, opens strong when button pressed and locks open with about 3/16" up and down and little side to side. It does rattle if shaken with the blade open as most of these 100+ year old switchblades do. The lanyard ring is not likely original. EX condition.