Grenade Stud Overmolding and Igniter Insert Design
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Solution Overview
Problem
Existing reduced-lethality shrapnel grenades lack improvements in design for enhanced safety and effectiveness, particularly in the structure and materials used for the studs and holding elements, which affect the distribution and kinetic energy of the shrapnel.
Innovation Solution
A reduced-lethality shrapnel grenade design featuring a globally annular part with a central barrel and radially outer flange, where the studs are formed from individual parts with chamfers and the holding element is created by overmolding synthetic material, ensuring low kinetic energy and secure assembly, with an insert to prevent igniter plug ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the igniter plug is held in place by conventional means in reduced-lethality grenades, then the assembly is simple to manufacture, but the igniter plug may be ejected during operation reducing reliability
Solution Approach 1:
An insert is introduced as an intermediary component between the igniter plug and the grenade structure. This insert provides dedicated retention features (recesses, protrusions, or threading) that securely hold the igniter plug in place, preventing ejection during operation while maintaining manufacturing simplicity through the use of standard fastening methods.
Solution Approach 2:
The grenade assembly is segmented into distinct functional components: the main grenade body, the insert, and the igniter plug. This segmentation allows each component to be optimized independently - the insert can be specifically designed for igniter retention without affecting the overall grenade structure or shrapnel distribution mechanics.
2Reliability
If studs are formed from individual parts with chamfers and overmolded holding element, then the shrapnel distribution is more effective and safer, but the manufacturing process is more complex
Solution Approach 1:
The holding element is merged with the grenade body through an overmolding process, creating a unified structure where the holding element and grenade body become integral parts. This combining ensures that the holding element is permanently attached and cannot detach, while the chamfered stud geometry ensures proper shrapnel distribution upon detonation.
Solution Approach 2:
The stud geometry incorporates chamfers at specific angles and dimensions, changing the physical parameters of the shrapnel pieces. These parameter changes (chamfer angles, stud dimensions, material composition) are optimized to control the fragmentation pattern and kinetic energy distribution, making the shrapnel distribution more effective and safer.
Data Source
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AI summary
The grenade has a mechanical maintenance structure (300) for maintaining studs (200) prior to operation of a spark-gap tube (100), so that studs are propelled at time of deformation/swelling of the structure under operation effect of pyrotechnic composition contained in the tube. The structure includes a material part that is molded on crown parts of the studs. An insert (400) is placed in a vicinity of an axial end of a molded part and includes a tapping part (416) that is used to support the tube and a projection (460) projects on the structure to avoid expansion of the molded part.