Listed here are U.S. patents issued to Challenge Machinery Co. for inventions related to their flat bed cylinder proof presses. Challenge held several more patents for platen presses, paper cutters and drills.
| U.S. Patent No. | Model / Descriptive Title | Inventor | Filing Date | Issue Date |
|---|---|---|---|---|
| 1816816 | Printing Press Bed Movement | Barney, Freeman | 1/31928 | 8/4/1931 |
| 2119747 | Inking Mechanism | Barney, Freeman Lee, J.E. | 12/28/1936 | 6/7/1938 |
| 2162816 | Proof Press | Barney, Freeman Lee, J.E. | 10/26/1936 | 6/20/1939 |
| 2592379 | Proof Press | Barney, Freeman | 11/8/1947 | 4/8/1952 |
| 2674943 | Proof Press | Barney, Freeman | 7/26/1948 | 4/13/1954 |
| 2962963 | Printer's Proof press | Barney, Freeman | 11/28/1955 | 12/6/1960 |
| 3288062 | Chase Lockup Bar Assembly | Westra, Dan P. | 11/4/1964 | 11/29/1966 |
| 3370533 | MA/MP series / Proof Press With Short Sheet Gripper Release | Argaubright, Ned A. Westra, Dan P. | 9/13/1965 | 2/27/1968 |