Tilting Vehicle Headrest Lock With Low-Stress Cable Routing
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Solution Overview
Problem
Existing headrests for vehicle seats face issues with cable deformation and breakage due to excessive force applied when tilting, leading to deteriorated operability.
Innovation Solution
A headrest design featuring a swinging body with an arcuate-shaped outer peripheral surface and a tubular portion on the base member, where the cable is retracted along a tangent line, reducing the angle of insertion and minimizing force on the cable, and a moving body that unlocks the locking device via a pushing mechanism, preventing large forces from being exerted on the cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cable is pulled to unlock the locking device when the headrest is tilted, then the locking device is unlocked, but the cable is bent significantly and receives large force causing deformation or breakage
Solution Approach 1:
A cable guide member is introduced as an intermediary component between the cable and the swinging body. This guide member has a guide surface that guides the cable in a specific direction, preventing the cable from being bent significantly when the headrest is tilted. The guide surface ensures the cable maintains a relatively straight path, reducing the force and bending stress applied to the cable during tilting operations.
Solution Approach 2:
The cable guide member features a curved guide surface that is optimized to match the natural bending path of the cable. This curvature allows the cable to follow a smooth arc rather than being forced into sharp bends, significantly reducing stress concentration and deformation risk while maintaining the unlocking function.
2Ease of operation
If the cable is pulled to unlock the locking device, then the locking device is unlocked, but the cable is bent significantly leading to deteriorated operability
Solution Approach 1:
The cable guide member serves as a mediator that maintains the cable's shape by providing a proper guiding path. This ensures the cable remains straight or follows a gentle curve, preventing significant bending that would deteriorate operability. The guide surface is designed to keep the cable in optimal condition for smooth operation.
Solution Approach 2:
The optimized curved guide surface allows the cable to maintain its natural shape while being pulled. The curvature is designed to match the cable's flexibility, preventing sharp bends that would compromise operability and ensuring the cable can be pulled smoothly and repeatedly without deformation.
Data Source
AI summary
A headrest for a vehicle seat has a base member attached to a seatback of the vehicle seat, a body frame attached to the base member so as to be capable of tilting, a locking device for locking the body frame with the base member so as not to be capable of tilting, and an unlocking device for unlocking the locking device. The unlocking device includes a swinging body attached to the base member so as to be capable of swinging and a moving body attached to the body frame so as to be capable of moving with respect thereto. The moving body moves with respect to the body frame by being pushed by the swinging body to unlock the locking device. The swinging body has a connecting portion to which one end of a cable is connected and an arcuate-shaped outer peripheral surface on which the cable is disposed. And the cable is retracted into a tubular portion provided on the base member from an entrance of the tubular portion when the cable is pulled to unlock the locking device. The entrance of the tubular portion is located substantially on a tangent line of the arc of the outer peripheral surface.