Patents by Inventor Darrell Haar

Darrell Haar 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).

  • Patent number: 4131408
    Abstract: A machine for making a dry cast concrete pipe. The machine has a cross head carrying a rotatable shaft extended downwardly into a core supported on a turntable. An outer form mounted on the turntable surrounds the core. A head attached to the lower end of the shaft is engageable with the core to raise the core out of the outer form in response to upward movement of the cross head. Arms secured to the shaft above the core rotate with the shaft to move concrete from the top of the core into the annular chamber between the core and outer form. An annular press ring mounted on a top table is moved into the top area of the annular chamber to compact concrete before the core is withdrawn from the outer form.
    Type: Grant
    Filed: August 3, 1977
    Date of Patent: December 26, 1978
    Inventors: Joseph P. Sehulster, Stephen N. Halbach, Darrell Haar, Theron L. Crawford