Helmet Chin Strap Fastener with Preloaded Finger Flap
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Solution Overview
Problem
Current chin strap fasteners do not reliably fail at a specific tensile load, leading to potential premature release of helmets, increased risk of strangulation, and difficulty in operation, especially for bearded individuals or those wearing gloves, and lack adaptability for different user characteristics.
Innovation Solution
A safety fastener design featuring a separate finger flap and a preloaded spring mechanism that allows the fastener to open at a defined tensile load, enabling one-finger operation and reducing the risk of hair or skin entanglement, with adjustable spring force and angle of inclination for precise failure point control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional quick-release catch is used with evenly distributed latching surface area, then the latching and support force of the fastener is increased, but the fastener cannot be opened easily by bearded individuals or those wearing gloves
Solution Approach 1:
The fastener is divided into two separate components: a plug and a housing. The plug contains a finger flap that can be operated independently, while the housing contains the latching mechanism. This segmentation allows the finger flap to be easily manipulated (improving ease of operation) while the housing maintains the secure latching function (maintaining strength).
Solution Approach 2:
A finger flap is introduced as an intermediary element between the user's finger and the latching mechanism. The finger flap acts as a mediator that can be easily grasped and manipulated, especially by those wearing gloves or with beards, while it transmits the opening force to the latching mechanism in the housing.
2Strength
If the latching surface area is evenly distributed around the fastener, then the latching force is maximized, but the fastener may fail prematurely at undefined load levels
Solution Approach 1:
The latching surface area is not evenly distributed but concentrated at a specific location in the housing. This local concentration of latching force creates a predictable failure point, allowing the fastener to fail at a defined tensile load level rather than at an unpredictable location, thus improving reliability while maintaining sufficient latching strength.
Solution Approach 2:
The design allows for adjustment of the spring preload force and latching surface characteristics to control the failure load parameter. By changing these parameters, the fastener can be configured to fail at specific, predictable tensile load levels, ensuring reliable operation across different application requirements.
3Ease of operation
If a separate spring mechanism is added to preload the finger flap, then the opening force required is reduced and operation is simplified, but the device complexity increases
Solution Approach 1:
The spring mechanism is merged with the finger flap assembly rather than being a separate, independent component. The spring is integrated into the finger flap structure, providing preload force that assists in opening the fastener while maintaining a compact design. This merging reduces the perceived complexity despite adding the spring function.
Solution Approach 2:
The spring mechanism provides self-service by automatically preloading the finger flap to assist opening without requiring additional user effort or complex control systems. The spring naturally maintains the finger flap in a position that facilitates easy opening, making the system self-regulating and reducing operational complexity.
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 fastener ensures reliable and safe release of helmets at a specific load, improving user safety and ease of operation across various conditions, while allowing for customization based on user characteristics.
Implementation Method 1
A safety fastener design featuring a separate finger flap and a preloaded spring mechanism that allows the fastener to open at a defined tensile load
Data Source
AI summary
A belt fastener for detachably connecting two belt ends has a housing and a plug, which can be clipped into the housing. The belt fastener can be a safety fastener opening if a predetermined tensile load acts on the belt ends. A separate finger flap is hinged to a front end of the plug for clipping it into the housing. The finger flap preloaded outwards in direction away from the plug by a separate spring. The finger flap can be brought in abutment with a stop surface of the housing by means of a stop surface opposite of the attachment point. Both stop surfaces are tilted forward by an angle of inclination (α) of >0°, particularly of 20°. In addition, two stop surfaces can be convexly or concavely curved.