RECESSED SCREW, FORMING PUNCH AND DRIVING TOOL

摘要

A screw includes a head having a top surface where a drive socket and drive regions are recessedly formed. Each drive region has two non-parallel side walls and two different drive walls. One drive wall is connected to the side walls to form a groove communicating with the drive socket. The other drive wall is connected between two adjacent side walls of two adjacent grooves. At least one of the drive walls slopes downwards from the top surface at a slope of at least 1 degree. Each side wall connecting between the drive walls deviates inwards by an angle difference of at least 1 degree. The slope and the inward deviation of the walls receive a driving tool firmly to prevent a swinging problem and enhance the torque transmission. A punch adapted to form the recessed screw also facilitates a long-term production without losing the accuracy thereof.

主权项

1. A recessed screw comprising a head with a top surface and a bottom surface opposite to said top surface, a shank extending downwards from said bottom surface of said head, and a plurality of threads spirally disposed on said shank;
wherein said top surface of said head has a drive socket recessedly formed thereon and a plurality of drive regions disposed around said drive socket, each of said plurality of drive regions having two opposite side walls and two different drive walls respectively connected to said two side walls, one of said drive walls being connected to said two side walls to define a groove communicating with said drive socket, another one of said drive walls being connected between two adjacent side walls of any two adjacent grooves, at least one of said drive walls sloping downwards from said top surface of said head at a slope of at least 1 degree, each of said side walls and said other drive wall meeting at a point from which a reference line is defined, each of said side walls connecting between said two drive walls to define a drive line which deviates inwards from said reference line toward a central portion of said drive region by an angle difference of at least 1 degree so that said two opposite side walls are not parallel to each other.