Headless Wire Binding Screw With Combined Slotted Robertson Drive
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Solution Overview
Problem
Current headless wire binding screws require multiple drive configurations for different regions, leading to inefficiencies in manufacturing, assembly, and marketing due to regional demands for specific drive shapes, such as Robertson and flatblade drives, which complicates the production and compatibility of circuit breakers.
Innovation Solution
A headless wire binding screw with a combination of slotted and Robertson drives allows use with both slotted and Robertson-type drivers, maintaining the same exterior dimensions and avoiding the need for redesign or modifications to existing circuit breakers, enabling low-cost manufacturing through adapted cold heading and thread rolling processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a headless wire binding screw uses a single drive configuration (e.g., Robertson or slotted), then it meets regional customer requirements, but it requires separate assemblies for different regions, increasing manufacturing complexity and inventory costs
Solution Approach 1:
The patent combines two different drive configurations (Robertson square drive and slotted drive) into a single wire binding screw by forming both drive shapes in the same screw blank. This merging eliminates the need for separate Robertson-drive screws and slotted-drive screws, reducing assembly variety while maintaining compatibility with both regional preferences.
Solution Approach 2:
The wire binding screw is designed with multi-functionality by incorporating both Robertson and slotted drive capabilities in one component. This universal design allows the same screw to be used across different regions and with different driver types, eliminating the need for region-specific assemblies and simplifying inventory management.
2Adaptability or versatility
If a headed combination drive screw is used, then both Robertson and slotted drives are accommodated, but the head increases exterior dimensions requiring redesign of circuit breaker housings and components
Solution Approach 1:
The patent extracts the head from the screw design, creating a headless wire binding screw. This removal eliminates the dimensional increase that would require redesign of circuit breaker housings, terminals, and other components. The headless design maintains the same exterior dimensions as traditional headless screws while still accommodating both Robertson and slotted drive configurations through the combination drive formed in the screw blank.
3Ease of manufacture
If conventional cold heading process is used to form combination drive in headless screw, then the drive closes up during thread rolling, preventing driver insertion
Solution Approach 1:
The patent changes the material parameter from conventional carbon steel AISI 1010 to a low-alloy steel containing specific amounts of carbon (0.15-0.30%), silicon (0.10-0.50%), and manganese (0.50-1.50%). This material parameter change increases the steel's strength and resistance to deformation, preventing the combination drive from closing up during the thread rolling process while still allowing proper formation of the drive shapes. The modified material properties ensure the drive remains accessible to drivers after manufacturing.
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 the use of multiple drive tools without altering circuit breaker designs, maintaining dimensional tolerances and allowing the headless wire binding screw to be retrofitted into current designs, reducing manufacturing and testing complexities while accommodating various regional requirements.
Implementation Method 1
The headed combination drive screw is manufactured using conventional cold heading production equipment. The underside of the head allows the equipment to support a screw blank while the combination drive (e.g., slot and Robertson drive) is formed in the screw blank.
Implementation Method 2
In the cold heading process the drive configuration is stamped into the blank before rolling the thread on the screw blank.
Data Source
AI summary
A headless wire binding screw for use in a circuit breaker contains a slotted drive in combination with a Robertson drive. The slotted drive is for use with a slotted-type driver (such as a slotted screwdriver) and the Robertson drive is for use with a Robertson-type driver (such as a Robertson screwdriver). The screw has a body with a diameter of constant size along the entire length of the body. The screw also has an external thread that is formed along the entire length of the body.