GB988283A - Improvements in or relating to handling devices having motor-operated jaws - Google Patents

Abstract

988,283. Fuelling and servicing reactors. COMMISSARIAT A L'ENERGIE ATOMIQUE. Feb. 2, 1962 [Feb. 3, 1961], No. 4070/62. Heading G6C. Apparatus for transferring fuel elements, control rods, control rod sheaths &c., to or from the core of a reactor comprises a frame 2 movable to the desired position and supporting a carriage 1 by means of a chain 4 and cable 11. The chain 4 is driven by a motor 3 and a sprocket 5 and passes over a pulley 6 supported by the frame 2 and is attached to the carriage 1 at 9, whereby the carriage may be raised or lowered by the motor. The cable 11 passes over pulleys 12 and carries a counterweight 10 and is attached at 13 to the carriage. Bars 8 guide the carriage in its vertical movement. A casing 15 mounted for rotational movement about a vertical axis in the carriage 1 is driven by means (not shown) through a pinion and worm arrangement 14, this casing being integral with a housing 16 and a tubular body 17. The lower end of the body 17 supports three pivoted jaws 20 spaced at 120 degrees and operated by axial movements of a cam member 22 carried by the lower end of a push rod 21 disposed within the body 17. The upper end of the rod 21 is theaded at 23 and engages a nut 23a integral with a shaft 24 and pinion 25 disposed within the housing 16. A driving pinion 27 connected to the pinion 25 through a pinion 26 is driven by a motor unit 28 disposed within the casing 15. Rotational movement of the rod 21 is prevented by a pin-and-slot arrangement 30, 31 and hence the jaws 20 may be operated by the unit 28. The pinion 26 is normally held in engagement with the pinions 25, 27 by a spring 60 but may be moved out of engagement by sliding movement along its shaft axis by means of a lug 59 carried by a pin 55, this pin being slidable in the housing 16 and biased by a spring 57. A roller 56 carried by the pin 55 cooperates with recesses 54, 54A, formed at selected vertical positions in a shaft 52, the arrangement being such that when the roller is not in a recess the pin 55 is displaced so that lug 59 displaces the pinion 26 and unit 28 cannot operate the jaws. Thus a safeguard is provided against operation of the jaws except when the carriage 1 is in a predetermined vertical position. For emergency use, the shaft 52 may be rotated to present a recessed surface 68 extending along its length opposite to the roller 56 whereby the jaws may be operated whatever may be the vertical position of the carriage. Micro-switches 48, 49 operated by the rod 21 give an indication to the operator of the jaw condition. When the jaws 20 are lowered on to an article to be lifted, e.g. a fuel element A, a feeler member comprising a pin 32 slidable within the cam member 22 is raised, this pin being coupled to a cam plate 35 operating micro-switches 37 whereby an indication is given to the operator. The feeler member also comprises three fingers 34 spaced at 120 degrees which function to give an indication when the article to be lifted is, e.g. a sheath which is gripped on its interior surface by outward movement of the jaws.