5,170,190 DATED DECEMBER 8, 1992

WATER SPORTMAN'S FACE MASK FOR VIEWING OBJECTS
ABOVE AND BELOW THE LINE OF VISION

A water sportsman's face mask for enabling the swimmer on or below the surface of a body of water to view objects which lie substantially above or below his normal line of vision without rotation of the swimmer's head or body. The mask comprises a frame, a lens mounted in the front of the frame, a flexible seal attached to the rear of the frame for forming a water-tight seal between the frame and the face of the swimmer, an adjustable strap for attaching the mask to the swimmer's head, and a pair of triangular prisms mounted on the lens. One face of the prism is mirrorized and is in oblique relationship to the lens. In one embodiment of the invention the prisms are rotatably mounted to the frame and are selectively adjustable to a forward operative position and to a rearward inoperative position.

The present invention provides these improvements by enabling a swimmer to view objects in a direction which is at a substantial angle to a swimmer's normal line of vision without rotation of the swimmer's head or twist of the swimmer's body. The invention resides in the integration of single optical prisms into a water sportsman's face mask which enables a swimmer to view objects substantially above or below the swimmer's normal line of vision when the swimmer is facing forwardly with his head erect.

In one aspect of the invention, a face mask is adapted to view objects above the swimmer. In a second aspect of the invention, a face mask is adapted to view objects below the swimmer. One benefit of the invention, in addition to the foregoing benefit, is that current face masks can be retrofitted to view objects either above or below a swimmer.

The invention comprises a frame which seals tightly on a swimmer's face, a lens mounted in the front portion of the frame for viewing objects directly ahead of the swimmer, in the direction of the swimmer's normal line of vision, an adjustable means for attaching the mask to the swimmer's head and a pair of optical prisms mounted on the mask, each having first a planar face which is adjacent to the lens, a second planar face which is in oblique relationship to said normal line of vision, and a third face which interconnects the first and second faces. The second planar face is positioned at an angle which internally reflects light rays that are at a substantial angle to the normal line of vision of the swimmer. The optical prisms may be separate and joined to the mask or may be unitarily formed with the lens of the mask.

The foregoing aspects, features and benefits of the invention, together with additional aspects, features and benefits will be more apparent from the ensuing description and accompanying drawings which describe the invention in detail.