Puzzling Zipper Fastener Is Really a Simple Device (Aug, 1930)

Puzzling Zipper Fastener Is Really a Simple Device
THE “Zipper,” long a popular fastening device for purses, sweaters, galoshes and other articles of similar nature, has remained a mystery to most of its users although, as the pictures here will show, the device is simplicity itself. The little wedge-shaped affair which appears to sew up or rip the article at will contains a scientifically shaped wedge which spreads the arms at just the right angle so they will release the socket from the arm below and opposite. Reversing the operation guides the knobs on the arms back into the tiny sockets where they hold firmly.