Patents by Inventor Percy Crofoot

Percy Crofoot has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Vent frames
    Patent number: 4026082
    Abstract: A flared peripheral wall has an inner end internal flange forming the margin of a vent opening and an outer end external flange. Ribs projecting outward from the peripheral wall can be embedded in concrete to prevent displacement of the wall. Screen cloth covering the vent aperture is secured to the inner end internal flange. The vent aperture is closable by a sheet cover having resilient retaining flanges or by a plug of foam plastic.
    Type: Grant
    Filed: February 24, 1975
    Date of Patent: May 31, 1977
    Inventor: Percy Crofoot