Self-Drilling Screw with Plastic Head and Ribbed Cutting Disk
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Solution Overview
Problem
Existing screws for fastening insulation boards with plastic and metal cover layers form thermal bridges, cause plastic detachment, and risk damage to metal facings due to metal-to-metal contact, requiring excessive force and potentially deviating from the intended path.
Innovation Solution
A self-drilling screw with a plastic screw head and a screw shank featuring a cutting disk with rib-like cutting devices and projections, designed for smooth cutting through plastic cover layers, and a thread that extends over half to three-quarters of the shank length, ensuring secure piercing and guiding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal washer is used in the screw, then the screw can effectively fasten the insulation board, but thermal bridges are formed
Solution Approach 1:
The harmful metal washer component is extracted and removed from the screw design. The patent replaces the metal washer with a plastic screw head that integrates the fastening function, thereby eliminating the thermal bridge while maintaining fastening strength through the threaded shank design.
Solution Approach 2:
The screw is designed as a composite structure with a plastic head and a threaded shank that can engage with metal or wooden substructures. This composite design allows the screw to maintain fastening strength through mechanical threading while the plastic material prevents thermal bridging.
2Ease of operation
If a twisted washer design is used, then the washer can be inserted into the insulation foam, but the plastic cover layer becomes detached
Solution Approach 1:
The cutting function is segmented into multiple rib-like cutting devices arranged on the underside of the screw head. These ribs create controlled incisions that guide the screw into the insulation foam without causing the plastic cover layer to detach, as each rib works independently to cut and guide the insertion path.
3Strength
If a metal washer is used, then the screw can be fastened, but damage to the metal facing occurs due to metal-to-metal contact
Solution Approach 1:
The metal washer that causes metal-to-metal contact damage is extracted and removed from the design. The plastic screw head directly contacts the metal facing without causing damage, while the threaded shank provides the necessary fastening strength through engagement with the substructure.
4Force
If a large force is applied to flatten the washer, then the washer contacts the lower metal cover layer, but the washer turns inside out
Solution Approach 1:
The washer component that requires flattening force and is prone to turning inside out is extracted and removed. The integrated plastic screw head design eliminates the need for separate washer flattening, as the head maintains its structural integrity during the fastening process.
5Measurement precision
If the screw deviates from the intended path, then setting accuracy is reduced, but the twisted washer causes path deviation
Solution Approach 1:
The cutting function is segmented into multiple rib-like cutting devices that create controlled incisions. These segmented cutting ribs guide the screw along the intended path by creating stable cutting edges, preventing the screw from deviating due to the twisting effect that would occur with a single twisted washer design.
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 prevents thermal bridges, minimizes plastic detachment, and securely fastens insulation boards without damaging metal facings, while allowing for flexible screw attachment options and efficient assembly.
Implementation Method 1
a cutting disk (3) to be engaged, and the screw shank (6) having a thread (7) and a drill bit (8), wherein the screw head (2) is made of plastic and the cutting disk (3) has cutting devices (5) designed like ribs on its underside
Implementation Method 2
projections (4) which can be arranged on the circumference of the cutting disk (3)... The protruding projections are used for smooth incisions, in particular in the plastic cover layer
Data Source
Figure 1~3
AI summary
The drilling screw (1) has a screw head (2) comprising a screwing tool and a cutting disk (3). A screw shaft (6) is provided with a thread (7) and a bore tip (8). The screw head is made of plastic. The cutting disk comprises rib-like cutting units (5) at a lower side for milling a hole in an insulating material plate. Projections (4) are arranged between the rib-like units. The projections protrude from an outer circumference of the cutting disk. A circular recess is formed between the screw shaft and the cutting disk. An independent claim is also included for a method for fastening an insulating material plate with a covering layer.