Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 9428945 | Casement and awning window opening limit device | Derek Ronald Gramstad, Scot J. Berkley | 2016-08-30 |
| 9181746 | Low profile high performance casement and awning window keeper | Michael Neff, Lee Bauman, Loren Rysavy, Derek Ronald Gramstad, Gregory J. Vetter | 2015-11-10 |
| 8813424 | Casement and awning window opening limit device | Derek Ronald Gramstad, Scot J. Berkley | 2014-08-26 |
| 8505240 | Casement and awning window opening limit device | Derek Ronald Gramstad, Scot J. Berkley | 2013-08-13 |