04167185 is referenced by 151 patents and cites 7 patents.

A resiliently flexible sealing element, conformable to the face of a wearer, in the form of a re-entrant flap is hingedly joined to and supported by a mask body in a spaced relationship thereto. The sealing element extends parametrically around the open side of the mask body and in selected locations thereabout is resiliently urged away from the mask body by web means disposed between the sealing element and the mask body. The web means provides pressure on the sealing surface of the sealing element directly at the deepest point on the user's face so as to eliminate the tendency of the sealing element or flap to pull away from the user's face at such selected locations.

Title
Face mask seal
Application Number
5/788237
Publication Number
4167185
Application Date
April 18, 1977
Publication Date
September 11, 1979
Inventor
Robert D Lewis
Coloma
MI, US
Assignee
A T O
OH, US
IPC
A62B 7/00
View Original Source