Drilling Screw Extrusion Joint for Reliable Connection
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Solution Overview
Problem
Existing two-steel screws face challenges in reliably connecting the head part and cutting part, leading to high reject rates and testing efforts, especially with long screws, due to alignment issues and insecure connections.
Innovation Solution
Incorporating an intermediate section made of corrosion-resistant material between the shank and cutting parts, connected via extrusion with a peg-like projection and cup-like recess, allowing for a secure and reliable connection through axial undercuts, and subsequently welding the head part to the shank section, enabling torque transmission and stable screw length determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the head part and cutting part are connected by known methods (gluing, welding, screwing), then the connection can be established, but the connection reliability is insufficient and alignement deviations occur leading to high reject rates
Solution Approach 1:
The screw is divided into three distinct parts: head part, intermediate section, and cutting part. The intermediate section acts as a separate component that facilitates reliable connection between the head and cutting parts through extrusion, while allowing independent optimization of each segment's function and material properties.
Solution Approach 2:
The intermediate section serves as an intermediary component between the head part and cutting part. It enables reliable connection through material flow and extrusion processes, mediating the connection between components that have different material properties and functional requirements.
2Ease of manufacture
If the head part and cutting part are arranged in axial alignment for thread production, then threading can be performed, but large alignment deviations occur in practice
Solution Approach 1:
The intermediate section acts as a mediator that absorbs and compensates for alignment deviations between the head part and cutting part. Its material flow capability during extrusion allows it to adapt to minor misalignments while maintaining proper axial orientation for subsequent threading operations.
Solution Approach 2:
The extrusion process changes the physical state and dimensions of the intermediate section, allowing it to deform and adapt to alignment variations. This parameter change enables the intermediate section to compensate for manufacturing tolerances and maintain proper alignment for threading.
3Reliability
If a long intermediate section is used for extrusion connection, then connection reliability improves, but the overall screw length increases unnecessarily
Solution Approach 1:
The intermediate section is designed with just sufficient length to achieve reliable connection through extrusion, rather than being excessively long. The extrusion process concentrates the connection function in a localized region, allowing the intermediate section to be shorter than traditional connection methods would require while maintaining connection reliability.
Solution Approach 2:
The intermediate section concentrates the connection function in a specific localized region between the head and cutting parts. The extrusion process creates a localized material flow and bonding zone that provides reliable connection without requiring the entire screw to be longer, maintaining compact overall dimensions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method ensures a secure, non-detachable connection between the cutting and head parts, reducing reject rates and testing efforts by providing a reliable axial and radial connection, allowing for efficient production of self-drilling screws with improved torque transmission and consistent screw lengths.
Implementation Method 1
the intermediate section is permanently connected to the cutting part by means of extrusion in such a way that the peg-like projection of the cutting part covers the intermediate section in the area of the cup-like recess at least in sections axially undercuts
Implementation Method 2
If the cutting part is connected to the intermediate section and this is permanently connected to the head part in the area of the shank section--for example by welding--the shank section, the intermediate section and the cutting part together form the screw shank
Data Source
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AI summary
The invention relates to a drilling screw, in particular a two-steel screw, comprising a head part and a cutting part, wherein the head part is produced of a corrosion-resistant material and has a screw head and a shaft segment and wherein the cutting part is produced of a hardenable or hard material, wherein an intermediate segment composed of a corrosion-resistant material is arranged between the shaft segment and the cutting part and is welded to the shaft segment, wherein the cutting part has a stud-like protrusion or a cup-like cut-out and wherein the intermediate segment has a cup-like cut-out or a stud-like protrusion, wherein the cup-like cut-out or the stud-like protrusion has, in the cross-section thereof, a driving profile having plurality of driving segments, wherein the stud-like protrusion is arranged in the cup-like cut-out and wherein the intermediate segment is permanently connected to the cutting part by means of extrusion in such a way that the stud-like protrusion of the cutting part axially undercuts the the intermediate segment in the region of the cup-like cut-out at least in some segments or that the stud-like protrusion of the intermediate segment axial undercuts the cutting part in the region of the cup-like cut-out at least in some segments.