Countersunk Screw With Integrated Punching And Milling Features
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Solution Overview
Problem
Existing countersunk screws face challenges in manufacturing complexity and achieving a clean surface after screwing, as they often require intricate designs and sharp edges that complicate the screwing process and result in bulging around the screw head.
Innovation Solution
A countersunk screw design featuring a punching device that cuts wood fibers around the screw head edge, combined with milling ribs or pockets, to create a smooth surface by first milling away wood and then cutting off fiber ends, ensuring a clean and flush installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional countersunk screw design with sharp edges is used, then the screw can cut into the wood, but it causes wood fibers to bulge around the screw head
Solution Approach 1:
The screw head is divided into multiple functional zones: a countersunk section for creating the recess, a punching device for cutting fibers, and a milling device for smoothing the surface. Each zone performs a specific function to achieve the overall goal of clean installation without bulging.
Solution Approach 2:
The milling ribs and punching device perform preliminary actions on the wood fibers before the screw head is fully driven in. The milling ribs first roughen and separate the fibers, then the punching device cuts them cleanly, preventing bulging during the final tightening phase.
2Shape
If a punching device is added to cut wood fibers, then surface smoothness is improved, but manufacturing complexity increases
Solution Approach 1:
The punching device and milling device are merged into the screw head structure itself rather than being separate tools. The punching device is formed by the edge of the countersunk section, and the milling ribs are integrated onto the outer surface, eliminating the need for separate components.
Solution Approach 2:
The screw head serves multiple functions: fastening the wood pieces together, creating a recess with the countersunk section, cutting fibers with the punching device, and smoothing the surface with the milling ribs. This multi-functionality reduces the need for separate operations or components.
3Productivity
If milling ribs are added to the screw head, then wood removal efficiency is improved, but the screw head design becomes more complex
Solution Approach 1:
The milling ribs are placed only in the specific region where wood removal is needed - on the outer surface of the countersunk section. This localized application of milling features provides the necessary wood removal efficiency without adding complexity to the entire screw head structure.
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
The solution enables quick and efficient screwing with a smooth surface finish, reducing manufacturing complexity and eliminating bulging issues by using a punching device and milling features to precisely form the indentation.
Implementation Method 1
the punching device now cuts the wood fibers around the edge of the screw head to form a hole which corresponds to the diameter of the screw head
Implementation Method 2
when screwing in the screw, the wood is first milled away at the point where the countersunk head is to be arranged, until towards the end of the screwing-in process the remaining fiber ends are cut off
Implementation Method 3
the punching device is formed by a sharp-edged edge of a shoulder surface, the diameter of which is at least as large as the diameter of the base of the countersunk section
Data Source
Figure 1~5
AI summary
The screw has a head formed as a countersunk head, a front screw end and a shaft (2) attached to the head. A screw thread partially extends over the shaft, and a punching unit is provided at the lower side of the head. The punching unit is arranged on the side of a countersunk section, which is averted to the front end. The punching unit has an axial distance from the base of the countersunk section. A cylindrical section (10) is formed between the punching unit and the base of the countersunk section.