V4 development began with a renewed interest in a rejected headband concept from the V3: controlled tension. Rather than designing several dimensions of flexibility into a mostly rigid frame, this strategy attempts to create a semi rigid structure from entirely flexible elements. By retaining only enough structure to produce the necessary clamping force, the need for the horizontal pivot on the earcups is removed, and the headband can be rolled up to reduce stowed size without the need for dedicated folding mechanisms. These combined advantages create the potential for a far cheaper and more easily manufactured design than the V3, at the penalty of a less compact and durable folded form.
Initial concept. Earcup slides along headband to adjust fit, while the retention bar at the center slides independently to adjust earcup angle. Additional headband structure not modeled, shown right.
Initial designs using two parallel steel cables had issues with lateral buckling, leading to three additional cables attached between them in a triple helix support structure (above right). However, this modification made the design far more difficult to manufacture. I have also experimented with using flat strips rather than wire to address the buckling issue, but several issues with the construction, earcup attachment, and vertical pivot mechanism remain.
Given the above issues, I decided to pursue a hybrid design, combining increased flexibility with a collapsing approach similar to the V3. With this approach in mind I quickly settled on a wireframe headband structure, as this allowed for ample flexibility with an extremely compact folded form, while avoiding the sharp edges and pinch points of the V3 sheet metal design. In an attempt to avoid play and tolerance issues at the interfaces between separate wire components, I initially approached the problem with an intertwined loop design using only 2 pieces of wire per side.The initial earcup hinge design uses two external sheet metal pieces to attach the ends of the lower wire loop. These pieces pivot independently, and also allow the wire ends to rotate, taking care of both axes of adjustment.
Increased integration of the headband and earcups, as well as the streamlined wireframe design, enabled further optimizations of the folding mechanism. By moving the hinge completely inboard, the majority of the headband structure can now be stowed within the earcup itself, approaching the smallest folded form possible.
Proof of Concept Prototype
Revised Design
First fully functional earcup assemblies
Developing...
