Latch Snowload Lever Electromechanical Actuator
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Solution Overview
Problem
Existing latch mechanisms fail to maintain proper synchronization between the ratchet and pawl under external loads like snow, leading to failed latching operations, and direct coupling of snowload levers can result in unintended pawl activation during decklid slamming.
Innovation Solution
A latch design incorporating a pivotably mounted snowload lever, an electromechanical release actuator with a motor, pinion gear, and reduction gear, and a nutscrew mechanism that interacts with both the snowload lever and pawl to ensure synchronized movement and prevent external loads from interfering with the ratchet's release position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a snowload lever is directly coupled to the pawl, then the pawl is kept in the released position under external loads, but the mechanism may be activated when the decklid is slammed, causing unintended pawl activation
Solution Approach 1:
The patent introduces an electromechanical release actuator as an intermediary between the snowload lever and the pawl. The actuator includes a motor, pinion gear, reduction gear, and nutscrew mechanism that mediates the interaction, ensuring the pawl is only disengaged when the ratchet is fully released, preventing unintended activation during slamming while maintaining reliability under snow loads
Solution Approach 2:
The patent replaces the direct mechanical coupling between the snowload lever and pawl with an electromechanical system. The electromechanical actuator uses electrical control signals to operate the motor and gear mechanism, substituting the purely mechanical direct coupling with a controlled electromechanical interface that prevents harmful unintended activation
2Reliability
If external loads like snow are present, then the ratchet cannot move to the open position, but the pawl may move independently causing latching failure
Solution Approach 1:
The patent implements preliminary action by using the electromechanical actuator to first fully release the ratchet from its latched position before disengaging the pawl. This sequence ensures that under external loads like snow, the ratchet is completely freed before the pawl moves, preventing independent pawl movement and latching failure while maintaining operational reliability
3Object-affected harmful factors
If a two-part pawl construction is used, then direct coupling problems are avoided, but the number of components increases
Solution Approach 1:
The patent uses an electromechanical release actuator as a mediator that eliminates the need for complex two-part pawl constructions. The actuator's controlled mechanism prevents harmful pawl activation during slamming without requiring the pawl itself to be divided into multiple parts, thereby reducing overall component complexity while still addressing the harmful factor
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 effectively prevents external loads from preventing the ratchet from fully releasing, ensuring reliable latching operations by maintaining the pawl in the disengaged position until the ratchet is fully released, thus enhancing the latch's operational reliability.
Implementation Method 1
an electromechanical release actuator (40) having a motor (42)
Implementation Method 2
A torsion spring 34 biases the snowload lever to the engaged position
Implementation Method 3
A return spring 52 is coaxially mounted about the lead screw 48 to urge the nutscrew 50 back to its starting position
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A latch comprises a ratchet moveable between a latched position and a released position with the ratchet being biased to the released position. A pawl is moveable between a ratchet-engaged position in which the pawl checks the movement of the ratchet and a ratchet-disengaged position with the pawl being biased to the ratchet-engaged position. An electromechanical actuator has an output member for moving the pawl to the ratchet-disengaged position with the actuator output member moving between a start position and an end position and vice versa. A snowload lever is moveable between a pawl-disengaged position and a pawl-engaged position, wherein, in the pawl-engaged position, the snowload lever blocks the actuator output member from returning to the start position.