Sicherheits-Sperrklinkenvorrichtung zur Verhinderung des Herausschleuderns von Regelstäben bei magnetischen Schrittheberantrieben für Regelstäbe

1307119 Controlling reactors COMBUSTION ENG Inc 30 June 1970 [8 July 1969] 31723/70 Heading G6C A nuclear reactor control rod anti-ejection latch for use with a magnetic jacking type control rod drive comprises pawls 18 which ratchet to allow insertion of the control rod, but which prevent withdrawal unless the control rod lift coil 13 is energized. The pawls 18 are pivotally connected to an outer housing member 10 by pins 19 and normally engage one of a series of grooves 17 on the control rod extension 12, being positively disengaged when an unlocking slug 20 is drawn down by the coil 13. A connecting link 24 is pivotally attached to each pawl 18 by a pin 27 and to a link 22 on the slug 20 by pin 25. Biasing means in the form of coil springs 28 are connected to the housing member 10 by pins 29 and to the connecting links 24 at points 30. In the normal position, the springs 28 pull the slug 20 upwardly against a stop 33 and also, since the points 30 are slightly outboard of a straight line between the points of connection of the springs with pins 29 and the pins 25, exert a minor radial force on the connecting links 24. The pawls 18 are thus forced into engagement with a groove 17. The location of the pivoted connections and the spring force is such that ratcheting of the pawls 18 occurs without displacement of the slug 20 and against a lesser spring force than is acting on the slug