1. HELMET MARKING TOOL Michael Meck, Katherine Bagwell, Chad Wilkinson, Tristan Assimos BACKGROUND INFORMATION PROJECT SCOPE FINAL DESIGN CONCEPT GENERATION TESTING ACKNOWLEDGEMENTS METRICS We would like to thank our sponsor, Chesapeake Testing, and our advisor Dr. Michael Keefe, and the rest of the Senior Design Staff. ALIGNMENT CLAMPING Chesapeake Testing (CT) performs a variety of ballistic tests for personal protective equipment, including military helmets. Patterns, based on specific benchmarks on the helmet, are drawn to ensure the testing is performed properly. The current process is primarily operator-dependent and takes 147 and 130 seconds for the V0 and V50 test markings, respectively. The scope of work is to design and prototype a device that accelerates and simplifies marking of two types of helmets for two types of testing. The two types of helmets, the Advanced Combat Helmet and Enhanced Combat Helmet, each have multiple revisions and sizes. The design should work for any profile of both types. The two types of tests are the V50 and V0 test, which find the projectile velocity at which fifty percent or zero percent of bullets penetrate the helmet, respectively. Figure 1. Marking pattern: V0 test (above); current tools used at CT for marking process (right). Note: metrics are listed with the most closely associated want. The correlations to the wants are determined by conversation with project customers and by study of marking process efficient and successful. MARKING Clamping: holding and securing the helmet in the correct position Marking: providing a method of marking the helmet that makes the correct pattern and minimizes operator variation Alignment: placing the helmet in the correct position to be marked The design has three main functional components that determine its success: alignment, clamping, and marking. Concept generation is broken down into these three parts. Benchmarking is used to help provide launching points. Figure 3. Clamping concepts, from left to right: crown-point clamp, exterior profile v-clamp, interior clamp. Figure 2. Alignment concepts, from left to right: revolving clamp concept, dial concept. The lasers, not pictured, would project from above from the top of the stand. Figure 4. Marking concepts, from left to right: rigid arm on a prescribed path (later linkage arm), flexible stencil, rigid track. The final design is chosen based on iterations of the concepts above in order to produce optimized functionality as a system. Metric Target Value Result of Test V0 Marking Time V50 Marking Time < 60 sec < 90 sec 19.0 sec 29.1 sec Acc. Of Dial Acc. Of Circle Acc. Of Lines Straight Lines Crown Point Acc. < 1 degree or < 1/10 inch < 3/16” < 5 degrees *With and without linked arm Total Cost< $2000~ $1300 Time to Find Crown< 10 sec~ 10 sec Compatible Helmet Types Marking Patterns 2222 All tested 2 For the project, the first manufactured prototype is the final product. As such, the team maximizes the number of interchangeable parts in the prototype to allow for future modifications based on test results. Testing can be performed on component and system level, while examining for any operator error. Alignment: uses a crosshair laser on rotating dial for manual alignment with benchmarks on helmet Clamping: uses a crown-point clamp with tripod base with rotating alignment Marking: uses the linked arm concept for manual drawing of test patterns CONCEPT SELECTION OVERVIEW Figure 5. Concept Drawings, from left to right: Full assembly, Clamp with gas-loaded springs and swiveling mount, Dial with revolving laser mount and linkage arm mount. WantMetric Efficient V0 Marking Time V50 Marking Time Effective Accuracy of Dial Accuracy of Circular Pattern Accuracy of Lines Straightness of Lines Crown Point Accuracy Cost Effective Total Cost User Friendly Time to Find Crown Universal Compatible Helmet Types Total Marking Patterns