Vehicle Hood Double-Pull Lock With Spring-Fail Safety Catch
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Solution Overview
Problem
Existing double-pull locks for vehicle hoods are prone to damage due to repeated actuation of the pawl, leading to potential unintentional unlocking, especially when the vehicle is in motion, as the spring of the pawl may get damaged or ejected from its seat.
Innovation Solution
A double-pull lock design with a safety catch mechanism where the pawl's spring is designed to maintain the lock closed only when functional, ensuring the safety catch retains the striker unless the pawl spring is operational, and incorporating a sensor to detect unsafe unlocking states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pawl with spring is used to lock the catch in double-pull lock, then the lock can be actuated repeatedly for double-security function, but the spring may get damaged or ejected from its seat due to repeated actuation, rendering the pawl inoperable and causing unintentional unlocking
Solution Approach 1:
The patent introduces a sensor that detects the position of the pawl spring beforehand and sends a signal to the control unit before unlocking occurs. This preliminary detection allows the system to prepare for potential spring failure by preventing unlocking commands from being executed, thereby avoiding unintentional hood opening while maintaining the double-pull operation capability.
Solution Approach 2:
The patent implements a feedback mechanism where a sensor continuously monitors the pawl spring position and provides real-time information to the control unit. The control unit processes this feedback signal and adjusts the unlocking operation accordingly - only permitting unlocking when the spring is in its correct position, thus ensuring reliability while maintaining operational functionality.
2Device complexity
If the pawl spring is removed or fails, then the device complexity is reduced, but the lock can no longer be reliably locked, creating a safety hazard when the vehicle is in motion
Solution Approach 1:
The sensor provides continuous feedback on the pawl spring position to the control unit. When the spring is absent or failed (detected by the sensor position), the control unit receives this feedback and prevents unlocking operations, thereby eliminating the safety hazard of unintentional unlocking while the spring issue remains unresolved.
Solution Approach 2:
The system uses the existing sensor infrastructure to automatically detect spring failure conditions without requiring additional complex detection mechanisms. The control unit autonomously decides whether to permit unlocking based on sensor feedback, making the system self-monitoring and self-protecting against spring failure hazards.
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 design ensures reliable and safe operation by preventing unintentional unlocking, maintaining the lock closed when the pawl spring is not working, and providing a redundant safety mechanism to prevent hazardous situations.
Implementation Method 1
a first spring (8) suitable for applying a force to the pawl (3) so as to maintain the pawl (3) in the locking position
Implementation Method 2
a second spring (9) suitable for applying a force to the safety catch (4) so as to maintain the safety catch (4) in the blocking position
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
A lock (100) for a vehicle hood comprises a catch (2), a pawl (3) and a safety catch (4) hinged in a box (A); the safety catch has an actuation arm (44) that abuts against an actuation pin (34) of the pawl; a first spring (8) pushes the pawl (3) and a second spring (9) pushes the safety catch; the second resultant force (E2) exerted by the second spring (9) on the actuation arm (44) of the safety catch is lower than the first resultant force (E1) exerted by the first spring (8) on the actuation pin (34) of the pawl.