Screw head punch

Abstract

An improved punch to punch socket on the head of a screw that extends the service life of the punch and upgrades the quality of the screw by having a recess formed on one end of the body of the punch, a punching head protruding from the center of the recess, and multiple wings are respectively extended from the sides of the punching head at a level lower than that of the head of the punch to create traces to release punching pressure to avoid deformed socket or formation of stress concentration point at the corner of the socket.

Description

BACKGROUND OF THE INVENTION [0001] (a) Technical Field of the Invention [0002] The present invention is related to a punch for screw head, and more particularly, to one that extends service life of the punch and upgrades quality of the screw. [0003] (b) Description of the Prior Art [0004] A screw, though a small element among all hardware products, is a must for the assembly of various types of objects. To facilitate driving a screw, the on the surface of the head of the screw is usually provided with a socket either in flat, cross or square shape. To prevent the socket from restricting the use of the tool, e.g., a screwdriver, the socket is made in a shape combining two or more than two of the head shapes. In the formation of the socket, a punch is used to punch into the surface of the screw head when the screw is molded. Each punch is subject to more than two hundred rounds of punching the socket; therefore, a very high punching force is created in the punching process. Generally,...

AI Technical Summary

Benefits of technology

[0005] The primary purpose of the present invention is to provide an improved structure of a punch for the head of a screw to extend the service life of the punch and upgrade the quality of the screw. To achieve the purpose, wings are provided on the sides of the punch head at a lever lower than that of the punch head so that when the punch is used to punch for a socket on the head of the screw, a flute slightly recessed will be formed on the sides of the socket to serve as a point for releasing the pressure incurred from the punching process, thus to prevent deformed socket or creation of stress concentration point on the corner of the socket.

Problems solved by technology

However, in the punching for comparatively complicated form of socket, e.g., cross, square, polygonal or their combinations, the concentration of stress at certain point occurs resulting in bouncing of punch force back to the punch or direct application of the force on the screw head during the punching process.

Accordingly, the head of the punch is damaged in short time, the socket is deformed or cracks appear on the corner of the socket.

However, the structure of the punch 1 has served its purpose to punch for a square socket on the head of the screw, the over-concentrated stress results in that the damaged punch to cause extra cost of punching; that the square socket is deformed to cause the failure in a sound insertion between the head of the screw and the tool (e.g. a screwdriver) thus to affect the fastening; or that cracks appear on the four corners of the square socket to cause collapse when the square socket is driven by the screwdriver thus to prevent the fastening.

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