Patent Number: 047818824
Section: claims

1. An apparatus for loading or unloading a fuel assembly in a nuclear reactor comprising: means for positioning a fuel assembly above the reactor;  a housing on said positioning means;  a pair of concentric inner and outer masts carried by said housing;  said inner mast having means thereon for gripping a fuel assembly;  means for vertically axially moving said inner mast relative to said outer mast; and  guide means on said inner and outer masts to align the inner mast centrally within the outer mast during vertical axially moving the inner mast relative to the outer mast, said guide means including a plurality of inner members disposed on the inner mast and complementary shaped outer members vertically spaced on the outer mast which cooperate with said inner members, means for supporting said outer members on said outer mast, means for pivoting said outer members relative to said support means towards and away from said inner members, and means for vertically aligning the position of said outer member.  a plurality of inner members disposed on the inner mast;  a plurality of complementary shaped outer members vertically spaced on the outer mast which cooperate with said inner members;  means for supporting said outer members on said outer mast;  means for pivoting said outer members relative to said support means towards and away from said inner members; and  means for precisely vertically aligning the position of said outer members. 2. The apparatus for loading or unloading a fuel assembly in a nuclear reactor as defined in claim 1 wherein said outer members on said outer mast comprise rollers. 3. The apparatus for loading or unloading a fuel assembly in a nuclear reactor as defined in claim 2 wherein said rollers have a concave groove therein and said inner members have a convex surface thereon cooperating with said groove. 4. The apparatus for loading or unloading a fuel assembly in a nuclear reactor as defined in claim 1 wherein said means for supporting said outer members on said outer mast comprises a framework about an opening in the wall of the outer mast and said outer members are rollers disposed on a shaft, and said shaft extends between two spaced side bars mounted for pivoted movement relative to said framework. 5. The apparatus for loading or unloading a fuel assembly in a nuclear reactor as defined in claim 4 wherein said framework comprises a top wall above said opening, a bottom wall below said opening and a plate extending between said top and bottom walls, said bottom wall comprises a block with a bore therethrough, and said side bars are secured to a pivot pin disposed in said bore for said pivotal movement. 6. The apparatus for loading or unloading a fuel assembly in a nuclear reactor as defined in claim 5 wherein said framework includes an aperture through said bottom wall and a cooperating aperture through said plate, with a bolt passing therethrough and threadedly engaged in the wall of the outer mast, and a groove is provided in the lower face of said top wall and a cooperating aperture through said plate, with a bolt passing therethrough threadedly engaged in the wall of the outer mast. 7. The apparatus for loading or unloading a fuel assembly in a nuclear reactor as defined in claim 4 wherein said alignment means comprises an alignment beam adjacent to and extending between the upper ends of the side bars, an alignment pin extending from one end of the alignment beam for vertically aligning the position of said rollers, and an adjustable device which contacts the alignment beam. 8. The apparatus for loading or unloading a fuel assembly in a nuclear reactor as defined in claim 7 wherein said adjustable device comprises a sleeve enclosing said alignment beam, a threaded shaft co-acting with said sleeve and extending from said sleeve outwardly through an opening in said plate, a hollow stud having threads on the internal and external wall thereof about said threaded shaft in the opening of said plate, having a shoulder thereon, for abutting the inside of said plate and a lock nut engageable with the threads of said threaded shaft, for abutting the outside of said plate. 9. A guide means for use in centrally aligning inner and outer masts of an apparatus including means for vertically axially moving said inner mast relative to said outer mast, said guide means comprising: 10. The guide means as defined in claim 9 wherein said means for supporting said outer members on said outer mast comprises a framework about an opening in the wall of the outer mast and said outer members are rollers disposed on a shaft, and said shaft extends between two spaced side bars mounted for pivoted movement relative to said framework. 11. The guide means as defined in claim 10 wherein said framework comprises a top wall above said opening, a bottom wall below said opening and a plate extending between said top and bottom walls, said bottom wall comprises a block with a bore therethrough, and said side bars are secured to a pivot pin disposed in said bore for said pivotal movement. 12. The guide means as defined in claim 11 wherein said framework includes an aperture through said bottom wall and a cooperating aperture through said plate, with a bolt passing therethrough and threadedly engaged in the wall of the outer mast, and a groove is provided in the lower face of said top wall and a cooperating aperture through said plate, with a bolt passing therethrough threadedly engaged in the wall of the outer mast. 13. The guide means as defined in claim 11 wherein said alignment means comprises an alignment beam adjacent to and extending between the upper ends of the side bars, an alignment pin extending from one end of the alignment beam for vertically aligning the position of said rollers, and an adjustable device which contacts the alignment beam. 14. The guide means as defined in claim 13 wherein said adjustable device comprises a sleeve enclosing said alignment beam, a threaded shaft co-acting with said sleeve and extending from said sleeve outwardly through an opening in said plate, a hollow stud having threads on the internal and external wall thereof about said threaded shaft in the opening of said plate, having a shoulder thereon, for abutting the inside of said plate and a lock nut engageable with the threads of said threaded shaft, for abutting the outside of said plate.