GB963215A - Improvements in and relating to latching mechanisms particularly for the control rods of nuclear reactors - Google Patents

Abstract

963,215. Reactor control rods. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. July 15, 1960 [July 16, 1959], No. 24541/59. Heading G6C. [Also in Division E2] An automatic latching mechanism comprises a member, such as a control rod 2 for a nuclear reactor, which is movable vertically in a passage 1, a detent 20, Fig. 3, supported in the passage and engageable with a recess 5 in the rod 2, a spring 22 for biasing the detent towards the rod 2, and a striker 6 operatively connected to the detent and operable by axial movement of the rod 2, to selectively cause the detent to be extended towards the rod or to be locked in a retracted position to allow freedom of movement of the rod vertically. The striker 6 is depressed by either a shoulder 4 or lip 3 on the rod, successive depressions of the striker causing the detent 20 to be held in turn in a locked position in which the detent is held in the wall of the passage and in an unlocked position, in which the detent is urged inwardly towards the rod 2. Each depression of the striker 6 moves a spring loaded latch rod 12 axially by engagement with a cam surface 7, the latch rod being bifurcated at its end and having an integral pin 15 which is situated in a slot 16 of a fixed plate. Axial movement of the latch rod 12 from the locked position of Fig. 5a carries the pin to slide along the slot until, on reaching the V-portion of the groove, the pin is urged, by springs 24 and 25 connecting the pin to a movable pivot pin 18, along the lower limb of the slot. The downward movement of the latch rod then causes one of the bifurcations to shift the pivot pin to the lower end of its slot. In this second, unlocked position the pin 23 of the detent 20, Fig. 1, is freed from a hook 13 of the latch rod. In practice, the control rod is mounted vertically so that from an unlocked position of the detent in which the detent is biased inwardly into the recess 5 of the rod and supports the rod, the rod is raised and lowered such that the lip 3 twice depresses the striker 6 to cause locking of the detent and permit downward movement of the rod. A number of detents may be used for a single control rod.