If you find a patent number or patent date by this manufacturer that is not on this
list, please contact the Site Historian.
Key to Links for Patent Information
USPTO = U.S. Patent Office .
Images of the actual patent can be viewed on the U.S. Patent Office web site but
a special TIFF viewer must be installed with your browser in order properly work.
More information on how to configure your computer to view these patents can be
found at TIFF image Viewers
for Patent Images.
DATAMP = Directory of American Tool And
Machinery Patents . A sister site to VintageMachinery.org with information
on patents related to machinery and tools. A much easier user interface than the
USPTO's for finding information on machinery patents.
|
3,004,458
|
Oct. 17, 1961
|
Hydraulic powered oscillating shear
|
Joe R. Dvorak |
Cosmos, MN |
This is the patent for the well-known Dvorak ironworker. It was apparently manufactured by the Dvorak family for a time, and then in 1966 or '67 the patent rights were acquired by Scotchman Industries, which continues to manufacture several models of hydraulically driven ironworkers. Meanwhile, the Dvorak family came up with improved designs which were manufactured by the Dvorak family which eventually organized as Dynamic Specialties, which became Uni-Hydro Inc. |