Integrally Molded Corrugated Latch Spring Mechanism
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Solution Overview
Problem
Existing spring-operated latch mechanisms for tiltable window sashes face high manufacturing and assembly costs due to the use of separate metal springs, and previous attempts to integrate the spring with the latch bolt using molded plastic were not suitable for long-term use.
Innovation Solution
An integrally molded latch bolt and spring with a unique transversely corrugated configuration, featuring U-shaped sections and semi-cylindrical portions, which allows for optimized spring performance without excessive stress and maintains the necessary elastic characteristics over many years.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate metal spring is used in the latch mechanism, then the spring provides reliable actuating force, but the manufacturing cost and assembly cost increase
Solution Approach 1:
The latch bolt and spring are combined into a single integrally molded plastic component. The spring is formed as an extension of the latch bolt, eliminating the need for separate metal spring and reducing assembly steps while maintaining the spring's actuating function.
Solution Approach 2:
The spring material is changed from metal to molded plastic, and the spring geometry is transformed into a corrugated configuration with wave-like sections. This parameter change enables the spring to be molded integrally with the latch bolt while still providing the necessary elastic characteristics.
2Ease of manufacture
If a plastic spring is integrally molded with the latch bolt, then manufacturing and assembly costs are reduced, but previous designs were not suitable for long-term use without breakage
Solution Approach 1:
The spring incorporates corrugated configuration with wave-like sections and U-shaped bends instead of straight rigid forms. These curved geometries distribute stress more evenly throughout the plastic material, preventing stress concentration and breakage during repetitive operation.
Solution Approach 2:
The spring design allows for dynamic deformation through its corrugated structure. The wave-like sections can compress and expand repeatedly, enabling the plastic spring to accommodate the full range of compression required during normal latch operations without excessive stress.
3Volume of moving object
If the spring is confined within the housing space, then the device size is reduced, but the spring may jam or resist retracting motion
Solution Approach 1:
The spring is divided into multiple wave-like sections with connecting portions between them. This segmentation allows the spring to compress in a controlled manner, with each section absorbing some of the compression, reducing lateral excursions and preventing jamming against housing side walls.
Solution Approach 2:
The corrugated configuration with U-shaped sections allows the spring to compress axially while the curved geometry prevents lateral buckling. The wave-like structure guides the compression motion, ensuring smooth retraction without jamming.
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 solution reduces production costs by eliminating the need for a separate spring and assembly steps while ensuring the spring's longevity and operational effectiveness, enabling reliable and cost-effective operation of the latch mechanism.
Implementation Method 1
an integrally molded latch bolt and spring member which incorporates a novel and significantly improved configuration of the spring element which not only provides a desired spring action but is suitable for repetitive operation over a period of many years without breakage and without significant diminishment of its necessary elastic characteristics
Data Source
AI summary
A latch bolt mechanism for tilting window sashes includes an actuating spring that is integrally molded of plastic material in one piece with the latch bolt. The spring has a transversely corrugated configuration, comprised of at least two transversely disposed wave-like spring sections. Each spring section includes a pair of oppositely oriented U-shaped sections having spaced apart semi-cylindrical portions at opposite sides joined by transverse connecting sections. In a relaxed configuration of the spring, the several connecting sections are substantially parallel to each other and are longitudinally spaced apart. In a compressed configuration of the spring the connecting elements lie at an angle to each other and the several semi-cylindrical portions are closely spaced or in contact providing for the required spring compression without excessively stressing the plastic material. Significant production economies are realized with the one-piece, molded construction of the latch bolt and spring.