Auto-Adjusting Headrest with Arc-Guided Tracking for Reclining Chairs
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Solution Overview
Problem
Office chairs with reclining functions often lack adjustable headrests that move harmoniously with the seat back, leading to discomfort as the user's head does not tilt back at the same rate as the seat, necessitating a headrest that adjusts vertically, forwardly, and rearwardly in coordination with the seat back rotation.
Innovation Solution
An ergonomic chair with a pivotally mounted headrest assembly on an arc-shaped frame, driven by a flexible cable and spring mechanism, allowing the headrest to move in an arc synchronized with the seat back's tilt, and featuring a cam arrangement for manual fine-tuning, ensuring comfortable support over a wide range of user sizes and head rotation angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed headrest is used relative to the seat back, then the structure is simple, but the headrest does not track the user's head motion as the seat back tilts, causing discomfort
Solution Approach 1:
The headrest is transformed from a fixed structure to a dynamic one that automatically adjusts its position. The arc-shaped guide bar with slides allows the headrest to move forward and backward in coordination with the seat back tilt angle, tracking the user's head motion dynamically without requiring manual intervention.
Solution Approach 2:
The headrest system uses the seat back's own motion to drive the headrest adjustment. As the user reclines the seat back, the cam mechanism automatically actuates the cable drive, which moves the headrest along the arc-shaped path without requiring separate power sources or manual controls.
2Adaptability or versatility
If the headrest is mounted vertically only, then the structure is simple, but it cannot provide support across wide ranges of seat back angles and user sizes
Solution Approach 1:
The headrest mounting is extended from a single vertical dimension to include horizontal movement along an arc-shaped path. The guide bar with slides enables the headrest to traverse both vertical and horizontal dimensions, providing adjustment in two dimensions simultaneously to accommodate various user sizes and recline angles.
Solution Approach 2:
The mounting structure is divided into independent components: the arc-shaped guide bar, slides for vertical movement, and a cam-cable mechanism for horizontal movement. This segmentation allows each component to handle specific adjustment functions independently, achieving complex two-dimensional adjustment through coordinated simple mechanisms.
3Ease of operation
If a manual adjustment mechanism is added for headrest positioning, then adjustability improves, but the mechanism becomes more complex and requires additional components
Solution Approach 1:
The manual adjustment spool is merged with the existing cable drive system. The spool integrates with the cam mechanism and cable assembly, allowing the user to fine-tune the headrest position by rotating the spool, which directly adjusts the cable tension and headrest position without requiring a separate adjustment mechanism.
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 auto-adjusting headrest provides comfortable support by tracking the user's head motion, allowing for easy initial adjustment without reaching, and maintaining support across various seat back angles, with a pinch force limited by spring tension for safety, supporting high forces without damage.
Implementation Method 1
a spring moves the headrest in an arc away from the user's head
Implementation Method 2
a cam arrangement may be employed to actuate movement of the flexible cable, and the cam arrangement includes a cable with an origin in the backrest assembly, looping over a pulley actuated by a cam
Data Source
AI summary
An ergonomic chair with an auto-adjusting headrest having a base assembly including floor base, a seat bottom, and vertical structure. A seat back frame and back plate are pivotally attached to the base assembly. An arc-shaped guide bar and head rest restraint are slideably disposed on the back plate. such that the back plate slides approximately parallel to the seat back frame. Arc shaped guide bar rotates as the seat back is tilted rearward and forward.