US 4,683,108 A · Locking screw apparatus and method for underwater remote replacement

Abstract

An apparatus and method for under water remote replacement of the screws which secure together first and second structures in the internal region of a nuclear reactor core, wherein the screws are received and counterbored screw bores in the first structure. First, one or more lateral recesses are machined in the side wall of the counterbore portion. Then an external hex head screw with a shoulder flange is inserted in the screw bore and is threadedly engaged with the second structure with the flange seated in the counterbore portion. A locking cup with a central hex opening is fitted over the hex head of the bolt in the counterbore portion. Then a bifurcated die is seated against the first structure with die fingers extending into the cup, and a drive member is driven through the die coaxially with the screw to move the die fingers against the side wall to deform it into the recesses, thereby locking the assembly in place.

Claims20

Dependent claims

A locking screw assembly for securing together first and second structures in the internal region of a nuclear reactor core, wherein the first structure has a screw bore therethrough with a counterbore portion formed in an outer surface thereof, said assembly comprising:

a lateral recess formed in the counterbore portion and spaced from said outer surfaces;
an elongated screw receivable through the screw bore for threaded engagement with the second structure, said screw having an enlarged shoulder flange dimensioned for seating in the counterbore portion and for rotation with respect thereto, and an angular drive head projecting axially from said shoulder flange and having a lateral width substantially less than that of the counterbore portion;
and a locking member disposed in the counterbore portion against said shoulder flange, said locking member having an angular opening therein shaped to receive said angular drive head therein for engagement with said locking member to prevent rotation with respect thereto, said locking member having a lateral projection engaged in said recess to prevent movement of said locking member with respect to the first structure.

Locking screw apparatus for securing together first and second structures in the internal region of a nuclear reactor core, wherein the first structure has a screw bore therethrough with a counterbore portion formed in an outer surface thereof, said apparatus comprising:

a lateral recess formed in the counterbore portion and spaced from said outer surface;
an elongated screw receivable through the screw bore for threaded engagement with the second structure, said screw having an enlarged shoulder flange dimensioned for seating in the counterbore portion and rotation with respect thereto and an angular drive head projecting axially from said shoulder flange and having a lateral width substantially less than that of the counterbore portion;
a locking member disposed in the counterbore portion against said flange, said locking member having an angular opening therein shaped to receive said angular drive head therein for engagement with said locking member to prevent rotation with respect thereto, said locking member having a deformable portion disposed adjacent to said lateral recess;
and means for deforming said deformable portion into said recess for engagement therewith to prevent movement of said locking member with respect to the first structure.

1 more element

Dependencies are inferred from the claim text.

Locking screw apparatus and method for underwater remote replacement

Life of this patent

Locking screw apparatus and method for underwater remote replacement

Life of this patent

Abstract

Claims20