Motorized furniture headrest assembly for seating systems
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Solution Overview
Problem
Conventional motorized actuatable headrest systems in recliner seating experience uneven motion and require excessive force and travel, leading to undesirable appearances and potential jamming, especially in wider headrests.
Innovation Solution
The system employs a motorized linear actuator pivotally mounted with a wheel unit and a cam wheel that engages a curvilinear cam track with a non-constant radius of curvature, positioned inwardly from the side supports, minimizing torsion and energy expenditure, and features cam wheel shrouds for debris protection and smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a linear actuator is mounted to the side support strut with a curvilinear cam track of fixed radius of curvature, then the actuator can control headrest actuation, but the motion becomes uneven causing one side to lag behind and creating undesirable appearance
Solution Approach 1:
The patent changes the parameter of the cam track from fixed radius of curvature to variable radius of curvature. The curvilinear cam track is designed with varying curvature radii that correspond to different positions of the cam roller, allowing the actuator to maintain proper engagement while achieving uniform angular motion of the headrest assembly, thereby eliminating the lagging side effect.
Solution Approach 2:
The patent introduces dynamic adjustment through the variable radius cam track design. As the cam roller moves along the curvilinear track during actuator operation, the changing radius of curvature dynamically adjusts the mechanical advantage and motion characteristics, ensuring even angular displacement of the headrest across its entire range of motion.
2Ease of operation
If the linear actuator is mounted to the side support strut, then headrest actuation is achieved, but excessive force and extent of travel are required
Solution Approach 1:
The variable radius of curvature in the cam track optimizes the mechanical advantage throughout the actuation cycle. By carefully designing the radius variations, the system achieves the desired headrest angular motion with reduced actuator force requirements and shorter linear travel distance compared to conventional fixed-radius cam tracks.
Solution Approach 2:
The curvilinear cam track with variable radius of curvature utilizes optimized geometric curvature to improve mechanical efficiency. The specific curvature profile is designed to minimize the work required by the actuator while maintaining smooth, even angular motion of the headrest, thereby reducing energy consumption.
3Extent of automation
If the cam roller is constrained within a curvilinear cam track of fixed radius, then the actuator mechanism functions, but jamming of hardware occurs due to uneven motion
Solution Approach 1:
Changing the cam track from fixed to variable radius of curvature eliminates the uneven motion that causes jamming. The variable radius profile ensures smooth, uniform angular displacement of the headrest, preventing binding and jamming of the actuation hardware while maintaining full motorized automation functionality.
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
This design ensures even angular movement of the headrest and lumbar support with reduced actuator travel and energy consumption, preventing jamming and maintaining smooth operation across varying headrest widths.
Implementation Method 1
The profile of the cam surface of the cam track has a non-constant radius of curvature. More specifically, the cam track is curvilinear, having at least a first portion which is straight and a second portion that is curved. As the cam wheel of the wheel unit of the motorized linear actuator member travels along the cam surface of the cam track member, the cam track member (i.e., the curvilinear track bracket), and thus the connected headrest frame, moves angularly.
Data Source
AI summary
A motorized furniture headrest assembly includes a headrest actuator and roller track that minimizes effort of a motor to impart angular movement of an associated headrest support mechanism. The roller track is curvilinear with a non-constant radius of curvature. The actuator and roller track are disposed sufficiently close to a center line of the headrest support mechanism to achieve angular actuation of the headrest support mechanism without one side of the headrest support mechanism lagging behind the other during angular movement.