Issued Patents All Time
Showing 1–15 of 15 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4969670 | Large diameter corrugated plastic pipe | Eldon G. Bonnema | 1990-11-13 |
| 4913473 | Large diameter double-walled plastic pipe | Eldon G. Bonnema | 1990-04-03 |
| RE32312 | Inlet and outlet baffle structure for sewage treatment tanks | Fred J. Crates, John J. Parker | 1986-12-23 |
| 4523613 | "Multi-layered corrugated conduit with ""black-eye"" like apertures" | John J. Parker, James L. Child, Jr., Donald W. Sting | 1985-06-18 |
| 4445542 | Arch end cap | John J. Parker | 1984-05-01 |
| 4397585 | Apparatus for inserting foldable conduit below ground | Michael Cook, Worthy O. Hassan | 1983-08-09 |
| 4374079 | Method and apparatus for manufacturing expanded and layered semiround plastic tubings | Larry A. Rosenbaum, James L. Child, Jr. | 1983-02-15 |
| 4363732 | Inlet and outlet baffle structure for sewage treatment tanks | Fred J. Crates, John J. Parker | 1982-12-14 |
| 4360042 | Arched conduit with improved corrugations | John J. Parker, James L. Child, Jr., Donald W. Sting | 1982-11-23 |
| 4359167 | Subterranean plastic tank | John J. Parker, Donald A. Lytle | 1982-11-16 |
| 4357190 | Method and apparatus for manufacturing non-round plastic tubing | John J. Parker, Donald W. Sting | 1982-11-02 |
| 4286808 | Snap-in tee connector | John J. Parker | 1981-09-01 |
| 4254885 | Subterranean plastic tank | John J. Parker, Donald A. Lytle | 1981-03-10 |
| 4247136 | Internal coupling structure and joint for pipe or tubing | Donald W. Sting, John J. Parker, Robert Biango | 1981-01-27 |
| 4245924 | Arch conduit | John J. Parker, James L. Child, Jr., Donald W. Sting | 1981-01-20 |