| Number | Date | Country | Kind |
|---|---|---|---|
| 48058 | Sep 1975 | IL |
| Number | Name | Date | Kind |
|---|---|---|---|
| 1617682 | Gibson | Feb 1927 | |
| 1751646 | Nieman | Mar 1930 | |
| 1909697 | MacBeth et al. | May 1933 | |
| 3389613 | Turnbull | Jun 1968 | |
| 3827309 | Dooley | Aug 1974 |
| Number | Date | Country |
|---|---|---|
| 473160 | Dec 1949 | IT |
| Entry |
|---|
| Strasser-Straight-Line-Direction-Product Engineering, 2/1960, pp. 61, 63. |