Dual-Material Caster Housing for Shock and Noise Reduction

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Solution Overview

Problem

Existing rollers used for moving furniture and luggage are not effective in absorbing shocks and reducing noise, particularly in environments like hospitals where fragile equipment and patient comfort are a concern, and they are often complex and costly to produce.

Innovation Solution

A caster design featuring a casing made of two materials with different flexibility, where the more flexible material is used between the housing and bearing to absorb shocks and reduce noise, achieved through bi-injection molding of polyamide and polyurethane, allowing for efficient sound and shock insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a single-material casing is used for the roller, then the structure is simple and manufacturing is easy, but shock absorption and noise reduction are insufficient

Engineering Contradiction:
Improveshock and noiseVSAvoidcasing structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The casing is constructed from two distinct materials with different flexibility characteristics. The first material (more flexible) is positioned between the housing and the bearing, while the second material (less flexible) forms the outer housing structure. This composite construction enables the casing to absorb shocks and reduce noise transmission while maintaining structural integrity and rotational functionality.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If two materials of different flexibility are used in the casing, then shock absorption and noise reduction are improved, but manufacturing complexity increases

Engineering Contradiction:
Improveshock and noiseVSAvoidcasing production
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The casing components are integrated into a single unified structure where the first and second materials are combined in one piece. The first material portion is seamlessly integrated with the second material portion, eliminating the need for separate assembly steps and reducing manufacturing complexity despite using multiple materials.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the second material portion is fixed to the first by a pin, then assembly is possible, but the structure becomes more complex and production cost increases

Engineering Contradiction:
ImproveassemblyVSAvoidcasing structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The first and second material portions are merged into a single integrated casing structure, eliminating the need for pins or other fastening elements to connect separate components. This integration simplifies the overall structure while maintaining the beneficial shock absorption and noise reduction properties of the multi-material construction.

Inventive Principle:
Principle #5Merging (Combining)

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 caster effectively absorbs shocks and reduces noise, providing a cost-effective and simple solution for moving furniture and luggage while maintaining directional mobility and ease of use.

Implementation Method 1

the second part 102 being that which is made of the material having the greater flexibility and being interposed between the housing 13 and the axial orifice of the bearing 16 so as to isolate the housing and the bearing from each other to achieve at least partially at least one of the following two effects: sound insulation, shock absorption on the wheels

Methodology Applied
Scientific EffectShock absorption: Damping

Implementation Method 2

the second part 102 being that which is made of the material having the greater flexibility and being interposed between the housing 13 and the axial orifice of the bearing 16 so as to isolate the housing and the bearing from each other to achieve at least partially at least one of the following two effects: sound insulation, shock absorption on the wheels

Methodology Applied
Scientific EffectSound insulation: Acoustic Absorption

Data Source

PatentEP2625048B1Shock-absorbing castor
Publication Date: 2015.06.24 TENTE ROULETTES POLYMERES BRUANDET
  • EP2625048B1 patent drawingFigure 1~2

AI summary

The invention relates to castors. The castor according to the invention is essentially characterized in that it includes a housing (10) consisting of a part (11) comprising at least one recess (13) capable of receiving a pivot (14) and defined along an axis (15), and a bearing (16) defined along an axis (17) perpendicular to axis (15), at least one wheel (20) capable of rolling on a surface Sd, a shaft (30) engageably mounted in the bearing (16), the wheel (20) being mounted in combination with said shaft, the part (11) consisting of at least two portions (101, 102) made of two materials having different flexibilities, respectively, the portion (102) having the greatest flexibility being inserted between the recess (13) and the axial opening of the bearing (16) so as to isolate the recess and bearing from one another. The invention can be used for castors for furniture or the like, in particular in a hospital environment, e.g. for beds, serving carts and walkers, as well as for moving suitcases, luggage, or the like.