Adjustable strap systems and related devices and methods

An adjustable strap system for a head-mounted display (HMD), comprising:

• a strap adjustment device, comprising:
• a rotatable cam element;
• at least one rotatable bearing element that is configured to inhibit movement of the rotatable cam element when the rotatable cam element is rotated in a jamming direction;
• and
• a biasing element coupled to the rotatable cam element to bias the rotatable cam element in a rotational direction;
• a first strap configured to extend from a first side of the HMD to a first side of the strap adjustment device;
• and
• a second strap configured to extend from a second, opposite side of the HMD to a second, opposite side of the strap adjustment device,
• wherein the biasing element is configured to allow for an increase in a length of at least one of the first strap or the second strap when a tension force is applied to at least one of the first strap or the second strap.

A method of manufacturing a strap adjustment device, the method comprising:

• engaging a first rack coupled to a first strap with a pinion gear;
• engaging a second rack coupled to a second strap with the pinion gear;
• positioning a rotatable cam element adjacent to the pinion gear, wherein the rotatable cam element includes at least one angled radially outer surface that is at an angle to a circumference of the rotatable cam element;
• positioning at least one bearing element adjacent to the at least one angled radially outer surface such that the at least one bearing element jams against the at least one angled radially outer surface when the rotatable cam element is rotated in a jamming direction;
• and
• coupling at least one spiral spring to and between the pinion gear and the rotatable cam element to allow for an increase in a length of at least one of the first strap or the second strap, wherein the at least one spiral spring is positioned and configured to bias the rotatable cam in a rotational direction.