Vehicle Seat Latching Device with Switching Action Surfaces
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Solution Overview
Problem
Existing latching devices for vehicle seats face challenges in preventing over-stroke pulling operations, which can impose excessive load on the mechanism, due to limited pull length allowance, making it difficult to ensure sufficient compactness and safety while maintaining operational efficiency.
Innovation Solution
A latching device design featuring a base member with a first and second link, where the first link's action surfaces are configured to switch contact with the second link during the pulling operation, allowing for increased pull length allowance by optimizing the rotational motion transmission, thereby reducing the risk of over-stroke pulling and enhancing compactness and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wire is made longer to provide pull length allowance, then over-stroke pulling can be suppressed, but the device size increases and compactness is compromised
Solution Approach 1:
The first link is divided into two functional surfaces: the first action surface for initial pulling stroke and the second action surface for subsequent pulling stroke. This segmentation allows the mechanism to handle extended pull length without requiring a proportionally longer wire, maintaining compactness while preventing over-stroke pulling.
Solution Approach 2:
The contact surface between the first link and second link dynamically switches from the first action surface to the second action surface during the pulling operation. This dynamic transition enables the mechanism to adapt to different pulling stages, effectively managing pull length allowance without increasing overall device volume.
2Reliability
If the wire is pulled hard to ensure full latching, then reliable engagement is achieved, but excessive load is imposed on the latching mechanism
Solution Approach 1:
The first action surface is designed to handle the initial pulling operation that achieves the primary latching engagement. By completing the main engagement function in the first stage, the mechanism prevents the need for excessive force in subsequent pulling, thereby avoiding excessive load on the latching mechanism while ensuring reliable engagement.
3Volume of moving object
If the latching device is made compact to meet design requirements, then device size is reduced, but pull length allowance becomes insufficient
Solution Approach 1:
Instead of extending the wire length in one dimension, the solution utilizes the rotational dimension of the first link to provide extended pull length allowance. The switching between first and second action surfaces during rotation effectively increases the functional pull length without increasing the linear dimensions of the device, maintaining compactness.
Data Source
AI summary
A first link (20) rotatably supported at a base member (10) of which a rotational motion is imparted by a pull member (e.g., wire 70), a second link (30) rotatably supported at the base member (10), a latch (40) including a hook-like portion (43) engageable with a rod-like portion (91), and a transmission mechanism (actuating lever 50) configured to transmit a rotational motion of the second link (30) to the latch (40) and to cause the latch to make a rotational motion are included. The first link (20) has a first action surface (24A) and a second action surface (25). The pulling operation made by the pull member (70) causes the first action surface (24A) to push a contact surface (33A), causing the second link (30) to make a rotational motion, and causes a surface of the first link (20) in contact with the second link (30) to be switched, partway through the pulling operation made by the pull member (70), from the first action surface (24A) to the second action surface (25).