Patent Number: 054003733
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates an elevational view of a preferred embodiment of the grid assembly fixture of this invention. As shown in FIG. 1, the fixture is comprised of a rectangular grid assembly plate 1 mounted on a pedestal 2 attached to a work surface 3, such as a work bench. The pedestal 2 is adjustable using the handle 4, which allows the grid assembly plate to be raised or lowered or tilted relative to the work surface 3, and then locked in place to provide a position most comfortable to the person assembling the grid. A suitable pedestal 2 work positioner is the Model 24001 manufactured by Marshall Industries, Dayton, Ohio. As best shown in FIGS. 3 and 4, the grid assembly plate 1 is a rectangular metal plate having four sides, each side having a flange 5 extending along a major portion of the length of each side. The top surface of the grid assembly plate is provided with a plurality of spaced slots 6 extending across the plate 1 in both directions. The slots 6 are adapted to receive the thin metal grid straps 7 that are interconnected at right angles to each other to form a network of interconnected grid cells similar to an "egg crate divider". The periphery or border of the grid is comprised of four grid straps 7 attached to each other and to the ends of the internal grid straps 7 to form a rectangular metal grid of interconnected open grid cells. The four border grid straps that make up the periphery of the grid are positioned along the four sides of the grid assembly plate 1 and are supported on the top surfaces of the four flanges 5, as illustrated in FIG. 1. As shown in FIGS. 1 and 2, a clamp support plate 8 is attached to the underside of each flange 5 on the sides of the grid assembly plate 1 and projects outwardly away from the flange 5. A toggle action clamp assembly 9 is attached to the end of each clamp support plate 8. The toggle action clamp assembly 9 is a commercially available assembly by which movement of the handle 10 moves a spindle 11 inwardly or outwardly relative to the sides of the grid assembly plate 1. The movement of the toggle action clamp assembly handle 10 may be manual or by a pneumatic piston and cylinder. For this embodiment, a Model 601 toggle action clamp assembly manufactured by Destaco Division, Drover Corporation, Detroit, Mich. was used. The end of the spindle 11 of each toggle action clamp assembly 9 is provided with an elongated clamping pad 12 adapted to move tightly against each of the sides of the grid assembly plate 1 just above the side flange 5. The clamping pad 12 is preferably about the length of the side flange 5 and preferably is provided with a face 17 for the clamping pad 12, as best illustrated in FIGS. 7 and 8. The toggle action clamp assemblies 9 and the clamping pads 12 are designed to temporarily press against and hold the four peripheral or border grid straps 7 tightly in place against the four sides of the grid assembly plate 1 and against the ends of the interconnected internal grid straps 7. After the four peripheral or border grid straps 7 are held tightly in place using the toggle action clamp assemblies 9 and the clamping pads 12, a rectangular strap retention assembly 13 is placed around the outside of the four peripheral or border grid straps 7 to hold the peripheral or border grid straps 7 in the proper position for welding of the grid strap 7 connections. When the rectangular strap retention assembly 13 is tightly in place holding the four peripheral or border grip straps 7 tightly against the sides of the grid assembly plate 1, the toggle action clamp assemblies 9 are released allowing the clamping pads 12 to be withdrawn from contact with the peripheral or border grid straps 7. As best illustrated in FIGS. 5 and 6, the rectangular strap retention assembly 13 is comprised of four rails 14 and four corner brackets 15 that allow the rails to be quickly connected to each other around the sides of the grid assembly plate 1 using openings in the corner brackets and knurled thumb screws 16. The clamping pads 12 are preferably provided with a face 17 for the clamping pad 12 that allows the rails 14 to be easily inserted through the face 17 of the clamping pads 12 while they are clamped against the border straps 7 and the sides of the grid assembly plate 1. This invention allows the efficient assembly of nuclear fuel assembly grids and is readily adapted to the assembly of grids of any geometry or size. It also provides a more accurate and precise alignment of the grid straps and components for further fabrication and welding. It is believed that the present invention and its advantages will be understood from the above description and the accompanying drawings and it will be apparent that changes may be made in the form, construction and arrangement of the apparatus of this invention without departing from the scope of this invention. PARTS IDENTIFICATION LIST 1. grid assembly plate PA0 2. pedestal PA0 3. work surface PA0 4. handle PA0 5. flanges on grid assembly plate PA0 6. slots on grid assembly plate PA0 7. grid straps PA0 8. clamp support plate PA0 9. toggle action clamp assemblies PA0 10. handle on clamp assemblies PA0 11. spindle PA0 12. clamping pad PA0 13. strap retention assembly PA0 14. rails PA0 15. corner brackets PA0 16. thumb screws PA0 17. face of clamping pad (12)