초록 ▼

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

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. An apparatus including the screws for flattening a metal plate is also provided.

대표청구항 ▼

1. A screw comprising: a first section having a shape of substantially a cylinder having a threaded side surface, at least part of which is for use for engagement with a nut;a second section for wrenching drive, the second section formed contiguously and concentrically to the first section and havin

1. A screw comprising: a first section having a shape of substantially a cylinder having a threaded side surface, at least part of which is for use for engagement with a nut;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; anda 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 a diagonal of a horizontal cross-sectional shape of the polygonal prism is larger than a diameter of the cylindrical portion, and a diameter of the first section is larger than the diagonal of the horizontal cross-sectional shape of the polygonal prism. 2. The screw of claim 1, wherein a 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. 3. The screw of claim 1, wherein the polygonal prism is a hexagonal prism.