Patent Number: 046831045
Section: description

Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a worm gear, worm drive or leadscrew drive mechanism 1 acting as a support, which is the basic element of the equipment. As can be seen from the cross section at the end of the device, the leadscrew drive mechanism is formed of a hollow section, with a leadscrew or spindle 2 extending along its longitudinal axis. An electric motor 3 turns the leadscrew 2 causing a non-illustrated leadscrew nut to move a support plate 4 attached to the nut along a slot 5 machined into one of the lateral surfaces of the leadscrew drive. The slot is sealed by means of a sealing lip device 6 even when the support plate is moved, since a non-illustrated connecting element between the leadscrew nut and the support plate 4 is enclosed in the sealing lip device 6. The leadscrew drive is thus sealed on all sides and can therefore be used in a water environment. A combination of such conventional leadscrew drives results in a device according to the invention as illustrated in FIGS. 2 and 3. According to FIG. 2, four leadscrew drive mechanisms 1a are mounted vertically on a base plate 7. A cover plate 8 which extends parallel to the base plate 7, rests on the front ends of the leadscrew drives facing upward. Electric motors 3 are disposed on the upper surface of the cover plate, while the drive elements thereof, which are each connected with a respective leadscrew 2 of a leadscrew drive mechanism, pass through the cover plate. Flanges 9 of the electric motors 3 serve to fix the cover plate 8 relative to the leadscrew drives 1a which extend in vertical direction. For this purpose, bolts 10 are used which pass through the flange and engage the front ends of the respective leadscrew drive mechanisms 1a. Two rotary plates or turntables 11 are disposed on the base plate 7. Each of these plates serves for receiving a fuel element 12. The cover plate has openings 13 opposite the rotary plates 11 for accommodating rotary plates 11a fitted with centering devices 14 for the respective fuel element. An actuator 15 is assigned to each rotary plate 11, 11a which can rotate the rotary plate by means of a V-belt 16. The actuators 15 assigned to one fuel element are synchronized and the centering device 14 also serves as a driving device for the fuel element. Each transverse leadscrew drive mechanism 1b is attached to the support plates 4 of two vertical leadscrew drive mechanisms 1a, by means of mounting straps 17. The leadscrew drives 1b, disposed on opposite sides and at the same level, jointly support a further leadscrew drive mechanism 1c with their plates 4a. The support plate 4a of the mechanism 1c carries a tool carrier 18. The electric motors 3 assigned to the vertical leadscrew drives 1a are electrically synchronized, producing a uniform, precise movement of the leadscrew drives 1b in the direction of an arrow 19. The same applies to the electric motors assigned to the leadscrew drive mechanism 1b which are disposed transversely, so that the leadscrew drive mechanism 1c is also moved precisely and uniformly in the direction of an arrow 20. The leadscrew drive mechanism 1c serves to move the tool or accessory carrier mechanism 18 in the direction of an arrow 21. The inspection of a fuel element is performed as follows: Non-illustrated hoisting gear attached to lugs 22 sets the equipment down in a water-filled fuel element storage pit 23. The fuel element is loaded into the equipment and the inspection can start at once. While the inspection proceeds, a second fuel element is placed into the equipment. Simultaneous loading and inspection leads to a considerable time saving. The rotary plate drive mechanism assigned to a particular fuel element positions the fuel element in such a way that the tool carrier can travel into gaps between the fuel rods. The electric motors 3 can be remotely controlled by non-illustrated cables and by a non-illustrated control unit disposed outside the fuel element storage pit, in such a way that the tool carrier moves to the desired inspection position. As a rule, the tool carrier which can be fitted with various cleaning, inspection, or repair tools, can enter a fuel element at several levels along the longitudinal extent thereof. If the tool carrier enters into the gaps between the fuel rods from different sides, the fuel element is turned 90.degree. by means of the rotary table or plate. The leadscrew drive mechanism 1c to which the tool carrier 18 is attached, can only travel outside the space delimited by a vertical leadscrew drive mechanism 1a. The distance along which the tool carrier can travel along the direction of the arrow 20 by means of the transversely disposed leadscrew drive mechanism 1b, corresponds at least to the width of a fuel element. FIG. 3 shows a top-plan view of a device of basically identical construction to FIG. 2, with the cover plate removed. The device is constructed for one fuel element only, and the leadscrew drive mechanism supporting the tool carrier 18 travels inside the space delimited by the leadscrew drive mechanism 1a. In FIG. 3, fuel rods 24 and gaps 25 therebetween into which the tool carrier enters, are also shown. The foregoing is a description corresponding in substance to German application Pat. No. 34 19 765.6, dated May 26, 1984, the International priority of which is being claimed for the instant application, and which is hereby made part of this application. Any material discrepancies between the foregoing specification and the aforementioned corresponding German application are to be resolved in favor of the latter.