Vehicle Seat Strap Restraint for Downward Displacement
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Solution Overview
Problem
Vehicle seat assemblies lack effective mechanisms to restrict downward movement of passengers during rapid changes in momentum, such as during impact events, whereas they often feature anti-submarining structures to limit forward movement.
Innovation Solution
A seat assembly design incorporating a seat bottom frame, a seat suspension structure with S-springs, and a strap structure that remains slack during normal sitting but becomes taut to restrict further downward movement beyond a certain elastic range, utilizing a cushion material to define a hip receiving surface and allowing elastic deformation within two movement ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the seat suspension structure allows elastic downward movement for passenger comfort, then passenger comfort is improved, but downward displacement of the passenger increases beyond the desired range
Solution Approach 1:
The strap structure changes its mechanical parameter from slack to taut state based on the displacement magnitude. During normal sitting, the strap remains slack allowing full elastic movement for comfort. When downward displacement exceeds the threshold, the strap becomes taut and restricts further movement, thus changing the system's mechanical properties based on the operating condition.
Solution Approach 2:
The strap structure is pre-positioned and pre-tensioned during installation to create a threshold effect. The strap is positioned to become taut only after a predetermined amount of downward movement occurs, providing comfort during normal use while being ready to restrict excessive displacement when needed.
2Object-affected harmful factors
If the strap structure is made taut to restrict downward movement, then downward displacement is limited, but passenger comfort during normal sitting deteriorates
Solution Approach 1:
The strap structure transitions from a static pre-tensioned state to a dynamic state where it remains slack during normal elastic movement and only becomes taut when displacement exceeds the predetermined threshold. This dynamic behavior allows the system to adapt to different operating conditions automatically.
Solution Approach 2:
The mechanical state of the strap changes from slack to taut based on the displacement magnitude, allowing the system to provide comfort during normal use and restriction during excessive displacement without requiring active control mechanisms.
3Object-affected harmful factors
If a rigid structure is used to prevent downward movement, then downward displacement is restricted, but the ability to provide comfort through elastic deformation is lost
Solution Approach 1:
The restraint function is segmented from the comfort function. The seat suspension structure (springs) provides elastic deformation for comfort, while the separate strap structure provides displacement restriction. This segmentation allows each component to optimize its specific function without compromising the other.
Solution Approach 2:
The strap structure dynamically engages only when needed, transitioning from a non-load-bearing slack state to a load-bearing taut state. This dynamic engagement preserves the elastic deformation capability of the suspension structure during normal use while providing rigid restraint when displacement exceeds the threshold.
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
Effectively limits downward passenger movement during rapid changes in momentum by transitioning from a comfortable elastic deformation to a restrictive tensioned state, enhancing safety by preventing excessive displacement.
Implementation Method 1
the passenger's weight causes downward movement of the hip receiving surface into the seat cushion receiving area, and also causes the seat suspension structure to undergo elastic downward movement within a first movement range providing comfort to the vehicle passenger
Implementation Method 2
Further downward movement of the hip receiving surface into the seat cushion receiving area causes the seat suspension structure to undergo further elastic downward movement within a second movement range causing the strap structure to become taught
Data Source
AI summary
A vehicle seat assembly has a seat bottom frame, a seat suspension structure, a strap structure and a cushion material. The seat suspension structure is fixed to the seat bottom frame and extends through a seat cushion receiving area of the seat bottom frame. The strap structure is attached to one of a front frame portion of the seat bottom frame and a front end of the seat suspension structure, and is attached to one of a rear frame portion and a rear end of the seat suspension structure. The strap structure extends through the seat cushion receiving area and is slack with a passenger seated on the cushion material. Downward movement of the seat cushion in response to a rapid change in momentum causes the strap structure to become taught restricting further downward movement of the passenger.