CPC A61M 16/0683 (2013.01) [A61M 16/0622 (2014.02); A61M 2205/0216 (2013.01); A61M 2210/0618 (2013.01); A61M 2210/0625 (2013.01)] | 18 Claims |
1. An adjustable headgear for a respiratory mask comprising:
an elastic portion having a longitudinal axis;
a non-elastic portion that is relatively inelastic compared to the elastic portion and having a longitudinal axis that is aligned with the longitudinal axis of the elastic portion, wherein the elastic portion is configured to provide a retraction force to the non-elastic portion in a direction of the longitudinal axis of the elastic portion;
a restriction mechanism configured to provide a force resisting movement of the non-elastic portion when the elastic portion is extended in the direction of the longitudinal axis of the elastic portion;
a support beam coupled to the non-elastic portion and extending along a portion of the adjustable headgear, wherein the support beam exhibits a resistance to buckling that is greater in a direction perpendicular to a length of the support beam than the non-elastic portion in a direction perpendicular to the longitudinal axis of the non-elastic portion; and
wherein the resistance to buckling of the support beam is greater in a superior-inferior direction than in a medial-lateral direction in use.
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