Round top set screw and application thereof

Abstract

A round top set screw is provided, including a first section having a shape of substantially a cylinder having a threaded side surface, a second section for wrenching drive, the second section formed contiguously and concentrically to the first section and having a shape of substantially a polygonal prism, and a third section formed contiguously and concentrically to the second section, the third section having a cylindrical portion and a round top having a convex shape, the edge of which contiguously connects to a side surface of the cylindrical portion, wherein the curvature of the convex shape is predetermined to prevent damages to a metal plate when it is pressed at an angle against the third section of the screw. A tool is provided for attaching the screw to a base board and securing it by using a corresponding nut.

What is claimed is: 
     
         1 . A wrenching tool for attaching a screw to a base board and securing it by using a corresponding nut, the wrenching tool comprising:
 a first unit configured to act on the screw comprising a first section having a shape of substantially a cylinder having a threaded side surface, a second section for wrenching drive, the second section formed contiguously and concentrically to the first section and having a shape of substantially a polygonal prism, and a third section formed contiguously and concentrically to the second section, the third section having a cylindrical portion and a round top having a convex shape, the edge of which contiguously connects to a side surface of the cylindrical portion; and   a second unit configured to act on the nut having a threaded internal side surface.   
     
     
         2 . The wrenching tool of  claim 1 , wherein
 the first unit comprises a first handle and a first cylindrical part, wherein the first handle is horizontally fixed to one end portion of the first cylindrical part, and the first cylindrical part has a section where a hollow is formed therein to have an internal side surface configured for engaging the second section of the screw; and   the second unit comprises a second handle and a second cylindrical part, wherein the second handle is horizontally fixed to one end portion of the second cylindrical part, and the second cylindrical part is a hollow cylinder having first and second internal side surfaces, the second internal side surface configured for engaging the nut.   
     
     
         3 . The wrenching tool of  claim 2 , wherein
 the first internal side surface of the hollow cylinder is configured for the first cylindrical part of the first unit to be inserted vertically and concentrically.   
     
     
         4 . The wrenching tool of  claim 3 , wherein use of the wrenching tool comprises operations of:
 forming a combination of the screw and the nut by tightening and locking to each other through threads:   screwing the screw of the combination to a certain depth in the base board by wrenching by engaging the nut with the second internal side surface of the second unit;   inserting the first cylindrical part of the first unit into the hollow cylinder;   unlocking the screw and the nut by wrenching by engaging, the second section of the screw with the internal side surface of the first unit, while engaging the nut with the second internal side surface of the second unit;   adjusting a height of the screw to reach a predetermined height by wrenching by engaging the second section of the screw with the internal side surface of the first unit; and   locking the nut to the screw to secure the screw to the base board by wrenching by engaging the nut with the second internal side surface of the second unit, while engaging the second section of the screw with the internal side surface of the first unit.   
     
     
         5 . The wrenching tool of  claim 3 , wherein use of the wrenching tool comprises operations of:
 screwing the screw to a certain depth in the base board by engaging the second section of the screw with the internal side surface of the first unit;   removing the first unit from the screw;   coupling the nut to the screw through threads by engaging the nut with the second internal side surface of the second unit;   inserting the first cylindrical part of the first unit into the hollow cylinder;   adjusting a height of the screw to reach a predetermined height by wrenching, by engaging the second section of the screw with the internal side surface of the first unit; and   locking the nut to the screw to secure the screw to the base board by wrenching by engaging the nut with the second internal side surface of the second unit, while engaging, the second section of the screw with the internal side surface of the first unit.