Lightweight Gear Reduction for Reliable Headrest Adjustment
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Summary
Problems
Conventional headrest adjustment mechanisms for aircraft seats, utilizing harmonic reduction drives, are complex, costly, and prone to failure due to a high part count, which is undesirable in aircraft applications.
Innovation solutions
A tilt adjustment mechanism with a reduced number of parts, featuring a profile shifted gear configuration with a driven gear having more teeth than the driver gear, and a rotation limiter feature to achieve a large reduction ratio in one step, resulting in a lightweight, cost-effective, and reliable headrest adjustment system.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If conventional harmonic reduction drives are used for headrest adjustment, then fine adjustment with large reduction ratio is achieved, but part count increases and device complexity increases
Why choose this principle:
The patent combines the driver gear and driven gear into a direct meshing arrangement, eliminating the need for separate cam profiles, rollers, and housing structures. This merging of components achieves the same fine adjustment function with significantly reduced part count and simplified mechanism.
Principle concept:
If conventional harmonic reduction drives are used for headrest adjustment, then fine adjustment with large reduction ratio is achieved, but part count increases and device complexity increases
Why choose this principle:
The gear assembly serves multiple functions simultaneously: it provides the reduction ratio for fine adjustment, limits rotation through the slot geometry, and directly transmits motion without intermediate components. This multi-functionality reduces the need for separate dedicated components for each function.
Application Domain
Data Source
AI summary:
A tilt adjustment mechanism with a reduced number of parts, featuring a profile shifted gear configuration with a driven gear having more teeth than the driver gear, and a rotation limiter feature to achieve a large reduction ratio in one step, resulting in a lightweight, cost-effective, and reliable headrest adjustment system.
Abstract
A headrest assembly for a seat, such as an aircraft pilot seat, including a headrest (202) and a headrest tilt mechanism (100). The tilt mechanism includes a headrest support (102), a casing (112) fixed to the headrest support defining a rotation limiter feature (122) determining a full aft headrest position and a full forward headrest position, a driven gear (114) rotatably disposed in the casing, a driver gear (116) rotatably disposed through an axial opening formed though the driven gear, an engaging feature for urging against the headrest, and an actuator for rotating the driver gear. The driven gear and the driver gear have a predetermined gear tooth reduction ratio and a predetermined axial shift distance such that the two gears are arranged in a profile shifted configuration.