Pivoting Closure Bar Locking Mechanism for Foldable Seat Backrest
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Solution Overview
Problem
Existing locking devices for foldable backrests in motor vehicles require a large amount of structural space and have complex constructions, which is inefficient.
Innovation Solution
A compact locking device design featuring a pivoting closure bar with a release recess and blocking recess, and a handle with a blocking pin, allowing for a small structural footprint and simple construction, where the closure bar is secured against axial displacement and can be easily assembled using a closure cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a linearly displaceable blocking bar is used to block the handle, then the locking function is achieved, but a large amount of structural space is required
Solution Approach 1:
The blocking element is changed from a linearly displaceable bar to a pivotable closure bar that rotates about a bar axis. This dynamic movement allows the same blocking function to be achieved within a smaller spatial footprint, as the pivoting motion confines the blocking element within a circular arc rather than requiring linear travel space.
Solution Approach 2:
The blocking mechanism transitions from one-dimensional linear displacement to two-dimensional pivoting motion. The closure bar rotates within a confined arc, utilizing angular displacement instead of linear translation, which significantly reduces the required structural space while maintaining the blocking function.
2Reliability
If a linearly displaceable blocking bar is used, then the handle can be blocked in the locking position, but the construction becomes complex and requires more components
Solution Approach 1:
The closure bar integrates multiple functions into a single component: it serves as both the blocking element and the structural link between the locking housing and handle. The release recess and blocking recess are formed directly on the closure bar itself, eliminating the need for separate blocking elements and reducing overall construction complexity.
Solution Approach 2:
The closure bar is designed as a multi-functional component that simultaneously provides blocking capability, guide the blocking pin through its recesses, and structurally connect the locking mechanism components. This universal design reduces the total number of parts required while maintaining reliable blocking functionality.
3Area of stationary object
If the closure bar is made pivotable about a bar axis, then a small amount of structural space is required, but the mechanism must ensure reliable blocking and release positions
Solution Approach 1:
The closure bar's pivoting mechanism automatically transitions between blocking and release positions based on the handle's position. The geometry of the release recess and blocking recess ensures that when the handle is in the locking position, the blocking pin engages the blocking recess, and when the handle is released, the pin moves to the release recess, providing self-actuating reliable positioning without additional springs or actuators.
Data Source
AI summary
A locking device for a foldable backrest of a seat, has a locking housing with a handle, the handle being pivotably between locking and unlocking positions and by which a pawl can be carried between retaining and non-retaining positions, and has a blocking element which is movable by a closable lock manually between a blocking position blocking the handle and a release position releasing the handle. The blocking element is a locking bolt mounted pivotably in the locking housing between the blocking and release positions and having release and blocking recesses. A blocking pin, in the release position of the locking bolt, projects into the release recess and is freely movable between the locking and unlocking positions. The blocking pin, in the blocking position of the locking bolt and the locking position of the handle, protrudes into the blocking recess and is blocked against pivoting into the unlocking position.