Latch Assembly Actuator Pivots Pawl to Overcome Seal Resistance
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Solution Overview
Problem
Shell doors, commonly used in military vehicles and sea-going vessels, are heavy and require a latching mechanism that can easily secure the door closed while overcoming the yield resistance of the door seal, without interfering with the door frame during closure.
Innovation Solution
A latching mechanism comprising a striker pin mounted to the door frame, a pawl with a first arm to hold the striker pin captive, and an actuator that pivots the pawl between latched and open positions using a biasing mechanism to ensure the pawl remains in the latched position until the actuator overcomes the resistance, allowing easy operation to secure the door.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a latching mechanism is designed to securely hold heavy shell doors closed against pressurized air or water, then the latching strength and reliability are improved, but the complexity of the mechanism increases
Solution Approach 1:
The latching mechanism is divided into distinct functional components: a pawl for latching, an actuator for operation, and a biasing mechanism for maintaining position. This segmentation allows each component to be optimized independently while working together to provide reliable latching with manageable complexity
Solution Approach 2:
The biasing mechanism automatically maintains the pawl in the latched position without requiring continuous external force or complex control systems. The spring-loaded design provides self-sustaining latching force, improving reliability while minimizing mechanism complexity
2Force
If the pawl is designed to overcome the yield resistance of the door seal, then the latching force is improved, but the ease of operation deteriorates
Solution Approach 1:
The mechanism uses dynamic movement of the pawl from an initial position to a final latched position, where the biasing mechanism provides mechanical advantage. This dynamic action allows the operator to overcome seal resistance more easily than static latching would require
Solution Approach 2:
The biasing mechanism acts as an intermediary that amplifies the operator's input force. The spring-loaded design provides a mechanical advantage that multiplies the force applied to the actuator, making it easier to overcome the door seal's yield resistance
3Reliability
If the latch remains engaged during door closure, then the latching security is improved, but it interferes with the door frame during closing
Solution Approach 1:
The mechanism is designed so that the door closes first to the proper position, and only then does the pawl engage the striker pin to latch. This preliminary closing action ensures the door is properly positioned before latching occurs, preventing interference with the frame
Solution Approach 2:
The pawl transitions from an initial non-interfering position to a final latched position dynamically during the closing sequence. This dynamic engagement ensures the latch only secures the door after it has properly closed, avoiding contact with the door frame during the closing motion
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 mechanism effectively secures the door closed by applying a leveraged force to overcome the door seal resistance, ensuring easy operation and reliable latching without interfering with the door frame during closure.
Implementation Method 1
an actuator configured to pivot the pawl from the latched position to an open position according to movement of the actuator, wherein the actuator comprises a biasing mechanism for urging the pawl to remain in the latched position until a resistance of the biasing mechanism is overcome by operation of the actuator
Implementation Method 2
the actuator comprises a linkage mechanism comprising at least a first and a second link member which are pivotally coupled to each other by a second floating pivot. In an embodiment the first link member is pivotally coupled to the pawl by a first floating pivot
Data Source
AI summary
A latching mechanism for securing a door mounted to a door frame comprises a striker pin mounted to the door frame; a pawl comprising a first arm for holding the striker pin captive when the pawl is in a latching position; and an actuator moveable relative to the door for opening or closing the door. The actuator is configured to pivot the pawl from the latching position to an open position according to movement of the actuator. The actuator comprises a biasing mechanism for urging the pawl to remain in the latching position until a resistance of the biasing mechanism is overcome by operation of the actuator.