Dual-Function Cam Lever for Active Pedestrian Hood Latch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current motor vehicle hood latch systems fail to automatically and safely open the hood in response to imminent front-end collisions, potentially causing severe injury to pedestrians, and they can inadvertently open during transportation after an accident, increasing safety concerns and costs.
Innovation Solution
A motor vehicle hood latch system with an actuation mechanism that includes a sensor-activated pyrotechnic actuator, a lift lever, pawls, and a control lever, which automatically moves the hood from a fully closed to a partially open position before impact, and includes a mechanism to prevent the hood from fully opening during transportation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the hood latch system is designed to automatically open the hood in response to imminent front-end collisions, then pedestrian safety is improved, but the device complexity increases due to additional sensors and actuators
Solution Approach 1:
The system performs preliminary action by detecting imminent collisions through sensors (accelerometers, impact sensors) and automatically actuating the hood release mechanism before the actual impact occurs. The control unit monitors collision signals and triggers the actuator in advance to move the hood to a partially open position, creating cushioning space before the pedestrian contact happens.
Solution Approach 2:
The patent introduces intermediary components including a control unit that processes sensor signals, a pyrotechnic actuator that converts chemical energy to mechanical motion, and a cam mechanism that transforms linear actuator motion into rotational hood movement. These intermediaries enable the automatic safety function while managing the complexity through specialized components.
2Extent of automation
If the hood latch system includes automatic sensor-activated actuation, then the ability to respond to imminent impacts is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces purely mechanical latch systems with an automated electromechanical system. The pyrotechnic actuator uses chemical energy conversion to generate mechanical force, while the control unit uses electronic signal processing to detect collisions and trigger the release mechanism, enabling automatic operation without manual driver intervention.
Solution Approach 2:
The system changes operational parameters by monitoring collision detection signals and transitioning the hood latch from a static mechanical lock to a dynamically controlled mechanism. The actuator modifies the latch state based on real-time sensor input, enabling automated response to changing collision conditions.
3Device complexity
If the hood latch system uses a dual-function cam lever mechanism, then the complexity of multiple separate mechanisms is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent merges multiple separate mechanical functions into a single dual-function cam lever mechanism. The cam lever simultaneously performs pawl disengagement and lift lever actuation, reducing the number of separate mechanisms needed for hood release. This integration consolidates multiple operational steps into one coordinated motion sequence.
Solution Approach 2:
The cam lever is designed as a multi-functional component that performs multiple tasks: it first engages with the pawl to release the latch, then engages with the lift lever to raise the hood. This universal component eliminates the need for separate mechanisms for each function, reducing overall system complexity while requiring precise manufacturing of its multiple cam surfaces.
4Reliability
If the hood latch system includes mechanisms to prevent inadvertent opening during transportation, then safety reliability is improved, but the device complexity increases
Solution Approach 1:
The system uses dynamic control through the cam lever mechanism that responds to specific collision signals rather than allowing random or inadvertent opening. The latch remains securely closed during normal transportation conditions, and only opens when the sensor-detected collision threshold is exceeded, providing reliable protection against false activation.
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 system effectively reduces the risk of pedestrian injury by creating a cushioned impact zone and ensures the hood remains secure during transportation, minimizing the risk of accidental opening and associated costs.
Implementation Method 1
an actuator configured for actuation in response to a signal detected by a sensor. The actuator has a member that is actuatable in response to the signal to act on the control lever
Data Source
AI summary
A hood latch for a motor vehicle is provided. The hood latch includes a lift lever, a pawl, a ratchet, a control lever and an actuator. The control lever has a first cam surface and a second cam surface. The actuator is configured for actuation in response to a signal detected by a sensor. The actuator is actuatable in response to the signal to move into engagement with the control lever to bring the first cam surface into operable engagement with the pawl to move the pawl out of locked engagement with the ratchet, whereupon the second cam surface is brought into engagement with the lift lever to rotate the lift lever into engagement with a striker, fixed to a hood of the motor vehicle, to move the hood to a partially open state.