Vehicle Seat Head Rest Speed Increasing Unit
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Solution Overview
Problem
Existing vehicle seat head restraint apparatuses face challenges in quickly and effectively restraining an occupant's head during collisions due to limitations in movement range, weight, and layout efficiency, with issues such as delayed operation and reduced injury reduction effect.
Innovation Solution
A vehicle seat design incorporating a support bracket, pressure receiving member, speed increasing unit, and head rest tilt mechanism, where the speed increasing unit enhances the motion of the pressure receiving member's rearward movement, transmitting it to the head rest tilt mechanism via a line member, allowing for quick forward movement of the head rest and efficient layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the center of rocking motion is lowered to increase operating speed of the head rest, then the head rest can restrain the occupant's head early, but the stays of the head rest deeply bend rearward under load, reducing the injury reduction effect
Solution Approach 1:
Instead of lowering the center of rocking motion to increase speed, the patent inverts the approach by placing the center of rocking motion at the lower end of the seat back frame. This inversion allows the head rest to move forward through a different mechanical configuration that maintains stay strength while achieving rapid deployment through the speed increasing unit.
Solution Approach 2:
The patent changes the mechanical parameters of the system by introducing a speed increasing unit with a line member that converts the rearward movement of the pressure receiving plate into amplified forward movement of the head rest. This parameter change allows the head rest to achieve high operating speed without compromising stay strength.
2Strength
If the stiffness of the stays is enhanced to lessen the deflection of the stays, then the structural integrity is improved, but the weight of the stays increases
Solution Approach 1:
The patent substitutes the traditional mechanical leverage system with a cable-driven pulley system (speed increasing unit). The line member and pulley mechanism replace the need for overly stiff stays, allowing the use of lighter stay materials while maintaining structural integrity through the mechanical advantage provided by the pulley system.
3Device complexity
If the head rest and pressure receiving plate move like a seesaw around an axis between them, then the mechanism is simple, but the components increase in size and weight, and layout efficiency is poor
Solution Approach 1:
The patent transitions from a two-dimensional seesaw motion to a three-dimensional cable-driven system. The line member runs through the seat back frame, allowing the pressure receiving plate and head rest to move in different spatial dimensions, reducing component size and weight while improving layout efficiency within the seat back structure.
4Power
If the pressure receiving plate is located in the upper part of the seat back to increase the link ratio, then the mechanical advantage is improved, but the start of operation is delayed due to the plate needing to be receded deep behind the seat back to prevent foreign body sensation
Solution Approach 1:
The patent introduces the line member as an intermediary element that connects the pressure receiving plate to the head rest tilt mechanism. This intermediary allows the pressure receiving plate to be positioned optimally for rapid response while the line member transmits the force through the seat back frame, maintaining mechanical advantage without delaying operation.
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 enables quick restraint of the occupant's head without delay, reduces the weight and size of the speed increasing unit and head rest tilt mechanism, and improves layout efficiency in the seat back, effectively enhancing injury reduction during collisions.
Implementation Method 1
a speed increasing unit which is connected with the one end of the line member and increases the speed corresponding to the motion of the pressure receiving member when the pressure receiving member moves rearward, thereby turning the line member in a direction such that the line member is pulled
Implementation Method 2
a line member having one end and the other end and located in the seat back... transmits a motion of the line member to the support bracket so that the head rest body moves forward when the line member is pulled
Data Source
AI summary
A vehicle seat comprises a head rest tilt mechanism which supports a head rest, a pressure receiving member contained in a seat back, and a speed increasing unit. The pressure receiving member moves rearward when it is pushed by the body of an occupant. The speed increasing unit has a base bracket, first and second arms, a roller, a pulley, etc. A part of a wire is wound in the shape of a U around the pulley. When the pressure receiving member moves rearward, the pulley moves to pull the wire. When the wire is pulled, the head rest tilt mechanism is driven to move a head rest body forward.