SPECTACLES WITH EXCHANGEABLE GLASSES

摘要

Eyeglasses have lenses resting in partial rims and these are held tight by means of a thread which travels in grooves on the lens edges. Adjustment and tightening of the tension of the thread to hold the lens on the eyeglasses is accomplished by a tensioning device carried on the eyeglasses. The tension of the thread is lessened to allow lens replacement or is increased to hold the lens in position with operation of the tensioning device.