Self-adjustment restrictor
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Solution Overview
Problem
Furniture glides with externally threaded stems tend to self-rotate within internally threaded nuts, leading to unlevel conditions during movement or relocation, as existing solutions like thread lockers, higher quality threads, jam nuts, and lock washers are either ineffective, expensive, or complicate re-adjustment.
Innovation Solution
A threaded insert with a polymer washer, where the washer's hole diameter is smaller than the stem's diameter, aligned with the insert's axis, provides frictional pressure to restrict rotation, preventing self-adjustment while allowing manual adjustment by compressing under load and expanding to relieve interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a typical commercial-grade threaded insert is used with a free-fitting thread, then the glide can be easily adjusted manually, but the glide tends to self-rotate and alter its pre-set height during movement or vibration
Solution Approach 1:
The patent changes the physical state of the polymer material from rigid to compliant, allowing it to deform under compression and expand under tension. This parameter change enables the polymer to provide frictional engagement during normal use while allowing easy manual adjustment when force is applied
Solution Approach 2:
The patent applies a polymer material with specific local properties (compliant, friction-providing) at the interface between the threaded insert and glide stem. This localized application of specialized material properties prevents self-rotation without affecting the overall adjustability of the mechanism
2Reliability
If thread lockers with chemical coating are applied to the threads, then resistance to self-adjustment is increased, but the application is difficult to perform with necessary precision and may provide too much or too little resistance
Solution Approach 1:
The patent replaces expensive, complex thread locker applications with a simple, inexpensive polymer ring that can be easily installed and removed. The polymer provides reliable friction engagement without requiring precise application techniques or specialized equipment
Solution Approach 2:
The polymer ring acts as an intermediary element between the threaded insert and the glide stem, providing the desired frictional engagement. This intermediary component simplifies the design by eliminating the need for chemical coatings or complex thread geometries
3Reliability
If higher quality threads with tighter matching are used, then resistance to self-rotation is improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent uses a simple, inexpensive polymer ring instead of expensive high-precision thread manufacturing. The polymer provides the necessary friction engagement through material properties rather than requiring tightly controlled thread geometries, significantly reducing manufacturing costs
4Reliability
If jam nuts or lock washers are added to the assembly, then resistance to self-rotation is increased, but the device complexity and installation time increase
Solution Approach 1:
The patent combines the functions of the threaded insert and the friction-providing element into a single integrated component. The polymer ring is installed within the threaded insert itself, eliminating the need for separate jam nuts, lock washers, or other additional fastening elements
Solution Approach 2:
The polymer ring serves multiple functions: it provides frictional engagement to prevent self-rotation, maintains thread engagement, and allows for easy manual adjustment. This multi-functional component replaces several separate elements that would otherwise be needed
5Reliability
If lock nuts or one-way fasteners are used, then resistance to self-rotation is improved, but the cost increases and re-adjustment is prevented
Solution Approach 1:
The patent creates a dynamic system where the polymer's engagement characteristics change based on the applied load. During normal use, the polymer maintains frictional engagement to prevent self-rotation. During manual adjustment, the applied force causes the polymer to deform and release its grip, allowing easy re-positioning
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
Effectively restricts self-adjustment of furniture glides without the need for additional components or high costs, ensuring stability and ease of re-adjustment, suitable for various furniture types and applications.
Implementation Method 1
the polymer washer is compressed by the threads of the stem and insert, thereby generating greater interference between the washer and stem
Implementation Method 2
Once this occurs, the leveling glide is more easily manually adjusted
Implementation Method 3
provides frictional pressure to restrict rotation
Data Source
AI summary
A device that prevents the self-adjustment of a leveling glide for the tubular legs of various types of furniture, including tables and chairs, is disclosed. The device comprises a threaded insert for a furniture leveling assembly that includes a polymeric washer secured to the bottom of the threaded insert. The polymeric washer is aligned with the axis of the internally threaded of the threaded insert and has a hole diameter that is smaller than the diameter of the externally threaded stem of the leveling glide.