Patent GB-1418307-A (GB)
Title: Locking mechanism for rod
IPC: G21C7/14
Filed: 1972-12-21
Abstract: 1418307 Releasable fastenings COMBUSTION ENG INC 21 Dec 1972 [23 Dec 1971] 59202/72 Heading. E2A [Also in Division G6] An assembly comprises a support, a rod 12 supported in and longitudinally linearly reciprocable relatively to the support, electromagnets and a catch 38 for reciprocating the rod, a latch 68 on the support and a mechanism comprising a slidable sleeve 62 pivotally connecting a toggle linkage of the latch and actuated to an over centre position by a spring 72 to engage the latch with the rod and a stop ledge 74 on the support limiting movement of the slider when the linkage is in the over centre position. The rod 12 has grooves for engagement by latches 68 a catch 48 and the catch 38 and is reciprocable within a tube 14 secured within a casing 10 'by means of screw engaging sleeves 18, 32 and 20, the sleeves 20 also being engaged by a tube 22 screw engaging a sleeve 24 which is urged into abutment with the casing by a nut 28. The catch 38 latches 68 and catch 48 are each pivoted to a magnetic member 34, 56 or 36 on the tube 14 and by a link to a slidable magnetic sleeve 40, 62 and 50, slidable within the magnetic members and urged downwardly by spring pressure so that the latches 68 engage the rod when the catches 38 and 48 are out of engagement whereby the rod is retained in position by the latches 68 in an emergency situation such as a power failure rendering actuating electromagnets A to F inoperative. Electromagnet F is actuated to release the latches 58. Electromagnets A, C and E are actuated to reciprocate the rod, the electromagnet A raises the member 34 to raise the rod one step when energised and energising the electromagnet C lowers the member 34 one step. Electromagnet E raises the sleeve 32 and spring 37 urges it downwardly a small amount to position the catch 48 to grip the rod for a holding action when the latch 38 is disengaged. The electromagnet B when energised raises the sleeve 40 and causes the catch 38 to grip the rod and when deenergised a spring 42 and gravity cause its, release. Energisation of the electromagnet D raises the sleeve 50 to cause the catch 48 to grip the rod, deenergisation releases the catch under the action of a spring 52 and gravity. The catch 48 holds the rod while the catch 38 and the member 34 are repositioned for the next upward step. The electromagnets B, F are in series in a circuit connected to a power supply 78bf, the electromagnets A, C, D, E being connected to a supply 78a to 78c connected to a power source 80 and a master timer 82 whereby the latches 68 are timed to disengage a short time after the catch 38 engages and the catch 48 engages the rod while the catch 38 disengages for the next step Non magnetic spacer shims 88; 90 may be inserted between the members 34 and 24 and their respective sleeves 40, 62 to increase the speed of operation of the catches and latches. The upper end of the rod is without grooves so as to prevent engagement of the latches whereby the rod may be lowered and the casing removed from its container. The casing may be secured to a removable head 11 of a nuclear reactor vessel 13 and the rod 12 may be a control rod.