TENET
Mid-Level Freeride Helmet
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Design updated ear pad mechanism to improve upon weak points in current design
Create low-profile slider mechanism that translates motion perpendicular to applied force
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Cycle and pull force testing, with iterative development process to meet internal standard
Designed, prototyped, and developed slider mechanism that required constraining multiple degrees of freedom in 3D space on organic surfaces
Innovative attachment system between outer shell and main helmet
Vent Slider Design
The industrial design team required a unique slider mechanism, with button actuation perpendicular to the functional direction
Open and closed positions
Overmolded button provided a high grip user interface as well as pressure to pull the functional and normal slider components against the shell. Balancing tolerances to optimize stack up clearance was particularly challenging
45 degree driver slot translated the user’s motion into the functional direction. this angle was chosen to balance the tradeoff of user input force and spacial constraints
Metal spring clips were press fit onto boss extrusions on the shell to provide vibration resistance to the slider componentry away from the button. Boss geometry was designed with a step to keep spring pressure consistent across samples during assembly
Shell Attachment
With a hybrid shell construction, the outer layer needed an assembly method that was precisely repeatable and durably attached
I designed ribs at the front of ABS shell to key into polycarbonate reinforced recesses in the foam. Once engaged, the shell hinges around this mate point until seated on the foam
Final product as assembled
Once seated, the goggle retainer bezel is fit to the shell, with a bolt passing through holes in both the retainer and shell to thread into an inmolded nut in the foam. This attachment method functionally hides the bond between the foam and exterior shell. Silicone glue is applied in strategic locations to prevent slight movement due to tolerancing
Ear Pad Tab Function
Due to some customer complaints on past models, I rethought the ear pad tab and receiver, allowing helmet designs to be more compact and for more consistent installation and removal quality
Due to injection parameter variability, assumptions made during hand calculations, and component tolerancing, pull force was always verified through physical testing
Referring to the Plastic Snap Fit Design Guide, I made calculations for various cantilever snap joint geometries and material selections to balance the 5-7kg desired pull force range and size constraints
FAI reports from each cavity where compared to pull force testing results. Tool safe modifications were made for each cavity until pull force testing repeatably fell into the allowable range