Patents by Inventor Pertti Helminen

Pertti Helminen 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).

  • Strength-grading of veneer sheets
    Patent number: 5524771
    Abstract: A method of enhancing the strength and of reducing strength variations of multi-layer wood, plywood or similar by measuring the density of the veneer sheets used in the production and by grading the veneer sheets accordingly. The density of the veneer sheets is measured in a manner known per se by using a high-frequency electromagnetic resonator (2). To build up layers of multi-layer wood, plywood or similar (12), veneer sheets confirmed to have a higher density are graded as surface sheets (13) and/or local density variations of central sheets (14) are reduced by mixing veneer sheets with various densities.
    Type: Grant
    Filed: March 2, 1994
    Date of Patent: June 11, 1996
    Assignee: Finnforest Oy
    Inventors: Matti Kairi, Pertti Helminen