Patents by Inventor Duane K. Marrs

Duane K. Marrs 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).

  • Golf club including putting green slope correction aiming lines
    Patent number: 4174839
    Abstract: A golf club, having a club head with an array of predetermined, easily visible, paired angled lines symmetrical about a visible center line on the club head top surface enables a golfer to establish a proper initial path for the golf ball so as to increase the putting effectiveness in the execution of putts on sloping greens.
    Type: Grant
    Filed: March 21, 1978
    Date of Patent: November 20, 1979
    Inventor: Duane K. Marrs