Vehicle Headrest Sleeve with Elastomeric Pad
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Solution Overview
Problem
Existing headrest sleeve systems for vehicle seats face issues with tolerance compensation, leading to slack and misalignment between rods and sleeve bodies due to manufacturing tolerances, which existing solutions attempt to address with pre-stressing and low friction mechanisms but lack simplicity and cost-effectiveness.
Innovation Solution
A sleeve device with a deformable rod-engaging portion featuring a flexible pad on its external side, formed using a two-shot moulding process, which is more flexible than the tubular wall material, to compensate for tolerances and reduce friction, while also damping vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-stressing and low friction mechanisms are used to compensate for tolerances, then slack between rods and sleeve body is reduced, but device complexity increases
Solution Approach 1:
The sleeve body incorporates an elastomeric layer that acts as a flexible element to compensate for manufacturing tolerances. This flexible layer deforms to accommodate variations in rod dimensions and sleeve geometry, eliminating the need for complex pre-stressing mechanisms while maintaining tight clearance and reducing slack between components.
2Ease of operation
If low friction materials are used to enable rod translation, then rod movement is facilitated, but tolerance compensation capability is reduced
Solution Approach 1:
The sleeve body is constructed as a composite structure with an inner low friction layer (such as PTFE or other lubricious material) overlying an elastomeric layer. The low friction layer enables smooth rod translation with minimal friction, while the underlying elastomeric layer provides tolerance compensation through elastic deformation, thus achieving both objectives simultaneously.
3Strength
If a rigid sleeve body is used to maintain structural integrity, then strength is improved, but vibration damping is reduced
Solution Approach 1:
The elastomeric layer in the sleeve body acts as a vibration damping element that absorbs and dissipates vibrational energy through hysteresis losses. The flexible nature of this layer allows it to deform in response to vibrations, converting mechanical vibration energy into heat, thereby reducing the transmission of vibrations through the headrest assembly while the outer structure maintains structural integrity.
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 effectively minimizes slack and misalignment, provides a tight fit between rods and sleeve bodies, and surprisingly dampens vibrations, offering a superior, simpler, and more cost-effective alternative to existing arrangements.
Implementation Method 1
a flexible pad, e.g. an elastomeric pad, in a rod-engaging portion which is deformable inwardly relative to the tubular wall
Implementation Method 2
The sleeve body, and rod engaging portion can be formed of a material having low friction qualities, to enable the headrest rod to translate with minimal friction within the passage
Implementation Method 3
this arrangement is surprisingly effective at damping vibrations in the headrest in use. The material of the pad can be selected to optimise its ability to take up any vibrations within the headrest assembly, during use
Data Source
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Figure 4
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AI summary
The present invention provides for a sleeve device (2) for a headrest, the device comprising a sleeve body for insertion into a vehicle seat, the sleeve body comprising a tubular wall (21) describing an inner axial passage and a rod-engaging portion which is deformable inwardly relative to the tubular wall, the rod-engaging portion comprising a flexible pad (4) on its external side, wherein the pad is configured to be urged, in use, to force the engaging portion into the axial passage and/or against a rod received within the axial passage.