Patents by Inventor Martin Haak, Sr.

Martin Haak, Sr. 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).

  • Scissor-type lifting device, particularly for a work platform
    Patent number: 5113972
    Abstract: A scissor-type lifting device, for example for a work platform, with a scissor mechanism which has for one scissor axis 4 only two scissor arms a and b connected with each other so as to pivot about this scissor axis. The moments of torque that arise in the scissor arms produce prestresses in the mounts of the scissor axis and render the scissor mechanism free of play.
    Type: Grant
    Filed: August 10, 1989
    Date of Patent: May 19, 1992
    Inventor: Martin Haak, Sr.