GB1131652A - Mechanism for controlling reciprocation of two rods connected by gearing - Google Patents

Abstract

1,131,652. Controlling reactors. BROWN BOVERI/KRUPP REAKTORBAU G.m.b.H. 25 May, 1966 [28 May, 1965], No. 23473/66. Heading G6C. [Also in Division E2] Mechanism for locking in a predetermined end position one rod 5 of a pair of rods, e.g. a nuclear reactor control rod 4 and a counterweight rod 5, geared together by driving gear means for effecting movement in opposite directions comprises slides 10, 11 mechanically coupled for movement in opposite directions perpendicular to the longitudinal direction of the two rods, the rod 5 to be locked having a locking pin 9 whereas the other rod 4 has a control element consisting of two pins 7, 8 so located that withdrawal and consequential displacement of the rod 4 from the gear means causes a displacement of the slides 10, 11 such that slide 11 engages the locking pin 9 of the rod 5 and moves it into and retains it in a locking position in which the gear means is disengaged from the rod 5. In the embodiment shown, the gear means consists of a pinion 6 engaging rack teeth on the rods 4, 5. The slides 10, 11 are coupled by means of a rotatable disc 13 provided with diametrically opposed pins 14, 15 which engage grooves 16, 17 in the slides. The counterweight rod 4 is heavier than the control rod 5 so that when released, the rod 5 is inserted into the reactor core from below, due to the rod 4 descending under its superior weight. The purpose of the locking mechanism is to lock the control rod 5 in its fully inserted position so that the counterweight rod 4 may be removed if this should be necessary. Whilst the two rods are in a normal operating position the two slides assume a position in which they do not interfere with the move - ments of the rods. When it is desired to remove the rod 4, this is pulled down beyond its normal end position which results in the lower pin 8 of the two pins 7, 8 engaging the obliquely cut corner of the lower slide 11 which is thereby displaced sideways until it rides under the locking pin 9. The other end of the slide 11 has two obliquely cut corners of 45 degrees slope, the upper being relieved at an angle of 10 degrees so as to push the locking pin 9 slightly upwards. The control rod 5 is thus lifted and its rack teeth disengaged from the pinion 6. At the same time, it is held in its raised position by the slide 11 carrying the pin 9 and the rod 4 can be pulled down further and extracted. When the rod 4 is reinstalled, the pin 7 displaces the slide 10 to one side, the disc 13 simultaneously moving the other slide 11 to the opposite side with consequential release of the locking pin 9. The rack of the control rod 5 thus re-meshes with the pinion 6 and normal operation can be resumed.