( 1914 of 1914 ) |
United States Patent | 3,569,720 |
Fredriksen | March 9, 1971 |
Photoelectric limit sensing assembly and system having photoelectric elements and logic arranged so that movement beyond a predetermined acceptable region is detected and which only permits movement in the proper direction to bring movement into the acceptable region.
Inventors: | Fredriksen; Thorbjoern Roland (Sunnyvale, CA) |
Assignee: |
Electroglas, Inc
(Menlo Park,
CA)
|
Appl. No.: | 04/789,281 |
Filed: | January 6, 1969 |
Current U.S. Class: | 250/548 ; 250/221 |
Current International Class: | B23Q 15/00 (20060101); G06m 007/00 () |
Field of Search: | 250/219 (Rg)/ 250/221,222,223 |
2883559 | April 1959 | Bailey |