Vehicle Lower Leg Support Linkage for Ingress Egress
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Solution Overview
Problem
Current vehicle seating assemblies face challenges in providing adequate comfort and convenience, particularly in transitioning between use positions and forward-pitched positions, due to the physical constraints of lower leg supports that can impede ingress and egress, especially in multi-row vehicles.
Innovation Solution
A vehicle seating assembly with a lower leg support that is rotatably coupled to the seat and features a linkage assembly with guide tracks, a motor, lead screw, and drive nut, allowing the lower leg support to transition between a stowed position and a deployed position, forming an acute angle with the seat, thereby increasing rotational freedom and reducing physical impedance for occupants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lower leg support is positioned in a conventional fixed location, then it provides leg support function, but it impedes ingress and egress to third-row seats
Solution Approach 1:
The lower leg support is made dynamically positionable between a deployed position (providing leg support) and a stowed position (clearing the path to third-row seats). The linkage assembly enables automatic transition between positions, making the system adaptive to different operational needs without requiring manual intervention.
Solution Approach 2:
The lower leg support is separated from the fixed seat structure and made into an independent, movable component. This segmentation allows it to be positioned independently - deployed when needed for support, and stowed when needed for access - resolving the conflict between providing support and enabling access.
2Ease of operation
If the lower leg support is made movable to clear the path, then ingress and egress are improved, but the structural complexity of the seating assembly increases
Solution Approach 1:
The linkage assembly merges multiple functions into a single integrated mechanism: it provides the rotational coupling between lower leg support and seat, enables automatic positioning through guide tracks, and coordinates movement through the lead screw and drive nut system. This consolidation reduces overall system complexity compared to having separate mechanisms for each function.
Solution Approach 2:
The linkage assembly acts as an intermediary mechanism between the lower leg support and the seat structure. Rather than directly modifying the seat or lower leg support structures, the linkage assembly mediates their interaction, providing controlled movement while maintaining structural integrity of both components.
3Adaptability or versatility
If the lower leg support forms an acute angle with the seat in stowed position, then rotational freedom is increased, but the lower leg support may contact the floor or front seat
Solution Approach 1:
The system dynamically changes the angular parameter of the lower leg support relative to the seat. In the stowed position, it forms an acute angle to maximize rotational freedom for forward-pitching the seat. The guide tracks and linkage assembly ensure this angular change occurs within safe limits, preventing contact with the floor or front seat while achieving the necessary rotational freedom.
Solution Approach 2:
The linkage assembly and guide tracks are designed to preemptively prevent harmful contact by controlling the stowing motion. Before the lower leg support can contact the floor or front seat, the linkage mechanism completes the stowing action and secures it in the acute-angle position, thereby preventing the harmful contact from occurring in the first place.
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 enhances the rotational freedom of the vehicle seating assembly, improving access to third-row seats by stowing the lower leg support below the seat, reducing physical constraints, and maintaining seatback upright position, which increases space for ingress and egress while maintaining comfort with an air bladder assembly for cushioning.
Implementation Method 1
a lead screw that is coupled to the lower leg support and is parallel to the one or more guide tracks, the lead screw having a first end and a second end, the first end of the lead screw being directly coupled to the motor, such that the motor imparts rotational motion to the lead screw, and a drive nut engaged with the lead screw such that rotation of the lead screw affects movement of the drive nut along the length of the lead screw
Implementation Method 2
an air bladder assembly having a calf portion and thigh portion, the calf portion being positioned on the exterior surface of the lower leg support and the thigh portion being positioned on the seat proximate to the forward end, the calf portion and the thigh portion being coupled to a common air supply
Data Source
AI summary
A vehicle seating assembly includes a seat, a seatback, and a lower leg support. The seat includes a forward end and a rearward end. The seatback is pivotably coupled to the seat. The lower leg support includes an interior surface and an exterior surface. The lower leg support is rotatably coupled to the forward end of the seat and is movable between a stowed position and a deployed position. The stowed position of the lower leg support places the lower leg support in an area below the seat. The stowed position of the lower leg support forms an acute angle with the seat. A linkage assembly is coupled to an underside of the seat and the interior of the lower leg support. The linkage assembly is responsible for transitioning the lower leg support between the stowed position and the deployed position.