Head rest
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Solution Overview
Problem
Existing headrests with adjustable front-back positions are prone to malfunction due to vibrations, as the urging direction of the lock urging member can be switched inadvertently, leading to incorrect engagement or disengagement of the engaging teeth and projections, even when the headrest is in use.
Innovation Solution
A headrest design featuring a lock switching member with a resistance mechanism that prevents the lock urging member from switching directions between lock and unlock states, ensuring stable engagement and disengagement through a cam and groove system, and a resin cover for structural support and material efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the urging direction of the lock urging member is switched between lock state and unlock state, then the headrest can be adjusted to different positions, but the urging direction may be switched inadvertently due to vibrations, causing incorrect engagement or disengagement
Solution Approach 1:
The lock switching member is designed to rotate dynamically in response to the second member's movement, transitioning between lock and unlock states. The resistance member provides controlled resistance to this rotation, ensuring stable engagement while allowing intentional position changes. This dynamic design enables the headrest to be adjusted to different positions while preventing inadvertent switching due to vibrations.
Solution Approach 2:
The lock switching member acts as an intermediary between the second member and the lock plate. It translates the movement of the second member into controlled rotation that either engages or disengages the lock plate with the engaging teeth. This intermediary mechanism ensures that only deliberate user actions can switch the urging direction, while vibrations are filtered out by the resistance mechanism.
2Reliability
If a lock switching member with resistance mechanism is added, then the reliability of engagement is improved, but the device complexity increases
Solution Approach 1:
The lock switching member combines multiple functions into a single component: it serves as both a switching mechanism for changing lock states and a resistance mechanism for preventing inadvertent switching. The resistance member is integrated into this switching mechanism, creating a compact assembly that reduces overall device complexity while maintaining high reliability.
Solution Approach 2:
The lock switching member is designed with multi-functionality, serving as both the switching element and the resistance-providing element. The same component that switches between lock and unlock states also provides the resistance mechanism through its interaction with the resistance member. This universal design reduces the total number of separate components needed in the system.
3Reliability
If the lock urging member constantly urges the lock plate in lock direction, then the engagement stability is improved, but the ability to disengage for adjustment is reduced
Solution Approach 1:
The lock urging member constantly urges the lock plate in the lock direction, providing stable engagement during normal use. However, the lock switching member can dynamically override this constant urging when the user intentionally activates it, allowing the lock plate to disengage for adjustment. This dynamic control mechanism maintains both stability during use and ease of adjustment when needed.
Solution Approach 2:
The lock urging member provides preliminary anti-action by constantly urging the lock plate toward the locked position, preventing unintended disengagement due to vibrations or minor forces. The resistance member in the lock switching mechanism provides similar preliminary anti-action against inadvertent switching. When the user intentionally activates the adjustment mechanism, these preliminary anti-actions are overcome, allowing controlled disengagement for position changes.
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 enhances safety by preventing unintended unlocking or locking during vibrations, ensuring the headrest remains securely adjusted and reducing material usage and weight while maintaining strength.
Implementation Method 1
a lock urging member configured to constantly urge the lock plate in a lock direction
Implementation Method 2
a backward urging member configured to urge the second member to rotate the second member backward
Implementation Method 3
a resistance member configured to apply resistance to movement of the lock switching member with respect to the second member by engaging with the first engaging groove or the second engaging groove
Data Source
AI summary
A headrest with a lock urging member in which unintentional change in an urging direction will hardly occur is provided. The headrest includes a first member, a second member, a backward urging member, a lock plate, a lock urging member, a lock switching member, and a resistance member. The lock switching member is provided with a switching pin abutment portion A, a switching pin abutment portion B, and a switching cam abutment portion. The lock plate includes a switching cam abutted portion. In a lock adjustment range, the lock switching member is moved together with the second member by the resistance member configured to apply resistance to movement of the lock switching member with respect to the second member. In addition, in rotation further forward beyond a forward adjustment limit position, the switching abutment portion B abuts against the switching pin fixed to the first member, so that the lock switching member does not follow the second member, whereby the headrest is unlocked.