Furniture Roller Pin Collar for Impact Damage and Bearing Play
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Solution Overview
Problem
Existing furniture castors are prone to damage due to the flat lower end of fastening pins resting directly on the castor neck, leading to potential tearing during impact, and suffer from bearing play caused by material shrinkage and manufacturing limitations, resulting in inaccurate guidance and reduced lifespan.
Innovation Solution
A castor design featuring a fastening pin with a central collar-like material thickening that forms a support and guide bearing, distributing loads more effectively and reducing the risk of damage, combined with complementary support elements on the roll neck to prevent deformation and tilting, allowing for play-free rotation and improved load handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the flat lower end of the fastening pin rests directly on the castor neck, then the structure is simple, but the castor neck is prone to damage during impact
Solution Approach 1:
The patent applies beforehand cushioning by providing a bearing surface on the fastening pin that extends beyond the castor neck opening. This protruding bearing surface acts as a pre-positioned load-distributing element that prevents direct impact on the castor neck bottom, thereby cushioning against damage before it occurs during impact events
Solution Approach 2:
The patent applies local quality by creating a specific bearing surface region on the fastening pin with different functional properties. The bearing surface is designed to protrude beyond the castor neck opening, creating a localized load-bearing zone that distributes forces away from the vulnerable castor neck bottom, while maintaining the simplicity of the overall structure
2Ease of manufacture
If the castor neck is made of plastic with a flat bottom, then production costs are low, but bearing play occurs due to material shrinkage
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the fastening pin bearing surface. The bearing surface is designed to extend beyond the castor neck opening by a specific distance, creating an interference fit condition that compensates for plastic shrinkage. This geometric parameter adjustment eliminates bearing play while maintaining plastic material usage and low production costs
3Strength
If the fastening pin is made of steel, then strength is high, but it causes wear on the plastic castor neck due to hard material
Solution Approach 1:
The patent applies local quality by creating a specific bearing surface region on the steel fastening pin with different functional properties. The bearing surface is designed to protrude beyond the castor neck opening, creating a localized load-bearing zone. This concentrates the steel-to-plastic contact in a controlled area, distributing the wear over a larger surface area and reducing the harmful wear effect on the plastic castor neck
Data Source
Figure 1~4c
AI summary
The roller has a support designed with a complementary arrangement adapted to a contour of a material thickening (23), at an edge area of a receiver opening of a roller-pin receiver for the material thickening. The material thickening is formed at a fastening pin (20) in a center pin section corresponding to an opening area of the roller-pin receiver. The material thickening expands to an upper pin end according to types of bands (24) or directly consecutive bands relocated from each other in a cascaded manner. An object-pin sleeve (40) is made of plastic.