Caravan Lock Thermal Expansion Mitigation via Homogeneous Plastic
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Solution Overview
Problem
Existing locks for caravans and campervans face issues with component calibration due to thermal expansion, leading to dimensional variations and mechanical wear, which reduces their operational life and effectiveness.
Innovation Solution
A lock design featuring a supporting base and control element with a rotatable axis, coupled with a movable element and uncoupling means, made from plastic materials to minimize thermal expansion effects and reduce mechanical wear, allowing for efficient operation and extended lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locks use multiple different materials for components, then the lock can achieve proper initial calibration and function, but thermal expansion causes dimensional variations that lead to mechanical wear and reduced operational life
Solution Approach 1:
The patent applies homogeneity by making the control element and operating element from the same plastic material (polyamide with 30% glass fiber reinforcement). This eliminates dimensional variations caused by thermal expansion between different materials, preventing the mechanical wear and calibration issues that occur when metal and plastic components expand at different rates.
Solution Approach 2:
The patent uses composite materials - specifically polyamide reinforced with 30% glass fiber - to create a material that combines the advantages of plastic (low thermal expansion, vibration damping) with the strength and rigidity of fiber reinforcement. This composite material resolves the contradiction by providing thermal stability while maintaining mechanical strength for reliable operation.
2Strength
If locks use metal components for strength, then the lock structure is robust, but thermal expansion and vibration cause mechanical wear and calibration drift
Solution Approach 1:
The patent uses glass fiber-reinforced polyamide composite material that provides both the structural strength needed for robust lock construction and the thermal stability required for calibration reliability. The glass fibers reinforce the plastic matrix to achieve metal-like strength while the plastic matrix provides low thermal expansion and vibration damping.
Solution Approach 2:
The patent changes the material parameter from traditional metal to fiber-reinforced plastic, fundamentally altering the thermal and mechanical properties. This parameter change eliminates thermal expansion issues while maintaining sufficient strength through the composite structure, thereby ensuring both robustness and calibration stability.
3Reliability
If locks use recurrent adjustment of clearances to overcome thermal variations, then short-term functionality is maintained, but the adjustments are ineffective and reduce lock functionality over time
Solution Approach 1:
The patent eliminates the need for recurrent adjustments by using homogeneous plastic material for both control and operating elements. This material homogeneity ensures consistent dimensional relationships across temperature variations, maintaining proper clearance and functionality without requiring user intervention or complex adjustment mechanisms.
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 lock achieves increased operational life and efficiency by limiting mechanical wear from thermal variations and vibrations, with the use of plastic components and controlled kinematic uncoupling, enhancing the lock's functionality and durability.
Implementation Method 1
these locks comprise a large number of components the motion of which must be meticulously calibrated so as to guarantee a correct closing or opening of the door. Moreover, these components are commonly made of different types of material which, having different thermal expansion coefficients, modify the relative dimensions
Data Source
AI summary
A lock includes a base and movable element connected to a handle operable by a user and movable between a first position corresponding to an open condition of the handle and a second position corresponding to a closed condition. An operating element is rotatably mounted on the base and connected to a device for releasing a closing panel, and is rotatable between a first position corresponding to an open condition of the panel and a second position corresponding to a closed condition. A transmission acts between the movable an operating elements and kinematically connects the movable and operating elements such that movement of the movable element causes rotation of the operating element. An uncoupling device acts on the transmission for disengaging kinematically, and in a controlled way, the movable element from the operating element to disable actuation of the operating element by the movable element.