 
                 Patent Grant
 Patent Grant
                     5149450
 5149450
                    | Number | Date | Country | Kind | 
|---|---|---|---|
| 4019215 | Apr 1990 | DEX | 
| Number | Name | Date | Kind | 
|---|---|---|---|
| 677965 | Ennis | Jul 1901 | |
| 2152396 | Williams | Mar 1939 | |
| 2760931 | Spring et al. | Aug 1956 | |
| 2782165 | Peterson et al. | Feb 1957 | |
| 3252906 | Beretvas | May 1966 | |
| 4274973 | Stanton et al. | Jun 1981 | |
| 4419254 | Kosaka et al. | Dec 1983 | |
| 4491607 | Wesala | Jan 1985 | |
| 4582616 | Kita et al. | Apr 1986 | 
| Entry | 
|---|
| Chemical Abstracts 103:73683e, vol. 103, 1985, p. 144, Laszlo, Hungary Patent No. 34,232, 1985. |