Patents by Inventor Douglas J. Herrick

Douglas J. Herrick 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).

  • Anti-theft hitch ball
    Patent number: 5395131
    Abstract: A generally spherical hitch ball has a downwardly extending neck and an outwardly extending flange which engages against the trailer hitch of a towing vehicle. A threaded shaft extends downwardly from the flange through an opening in the hitch. The coupling device is fixed to the hitch by a nut which is threaded on the shaft and engages a washer against the hitch. The nut is retained on the threaded shaft and positively prevented from escaping by a cylindrical pin which extends through an inclined hole formed in the hitch ball and the shaft. The pin has a head which is biased upwardly by a spring against the trailer arm where it fits over the ball. When the trailer arm is locked in place the pin head is inaccessible and the nut may not be removed.
    Type: Grant
    Filed: April 22, 1994
    Date of Patent: March 7, 1995
    Inventor: Douglas J. Herrick
  • Detachable barrier for a doorway
    Patent number: 5271449
    Abstract: A system for providing a detachable barrier, preferably a screen barrier, on a doorway, garage opening or the like is provided. The barrier may be removably attached and adjusted to provide a custom-fit appearance.
    Type: Grant
    Filed: June 3, 1992
    Date of Patent: December 21, 1993
    Inventor: Douglas J. Herrick
  • Locking hitch-pin for trailer
    Patent number: D356763
    Type: Grant
    Filed: July 6, 1993
    Date of Patent: March 28, 1995
    Inventor: Douglas J. Herrick