Automatically adjusting headgear for patient interface

A patient interface comprising:

• a mask;
• and
• a headgear for securing the mask to a user's face, the headgear comprising:
• an elastic portion configured to provide a retraction force;
• a non-elastic portion configured to be inelastic in comparison to the elastic portion;
• and
• a restriction mechanism connected to the non-elastic portion and to the elastic portion, the restriction mechanism configured to require a first resistance force to permit elongation of the headgear and having a second resistance force in response to retraction of the headgear, the restriction mechanism comprising a directional lock arrangement, the directional lock arrangement comprising:
• a housing having a cavity, and
• a lock member within the cavity;
• the non-elastic portion comprising a core member, the core member passing through an orifice in the housing and an orifice in the lock member;
• wherein in use, the core member is substantially free to move in a free movement direction during retraction of the headgear, and when the core member is pulled in a direction opposite to the free movement direction to elongate the headgear the lock member creates an angled path for the core member, increasing friction between the lock member and the core member;
• wherein the directional lock arrangement comprises a first lock stage comprising the lock member and a second lock stage comprising a second lock member, the first lock stage having different locking behavior or characteristics from the second lock stage.

A patient interface comprising:

• a mask;
• and
• a headgear for securing the mask to a user's face, the headgear comprising:
• an elastic portion configured to provide a retraction force;
• a non-elastic portion configured to be inelastic in comparison to the elastic portion;
• and
• a restriction mechanism connected to the non-elastic portion and to the elastic portion, the restriction mechanism configured to require a first resistance force to permit elongation of the headgear and having a second resistance force in response to retraction of the headgear, the restriction mechanism comprising a directional lock arrangement, the directional lock arrangement comprising:
• a housing having a cavity, and
• a lock member within the cavity;
• the non-elastic portion comprising a core member, the core member passing through an orifice in the housing and an orifice in the lock member;
• wherein in use, the core member is substantially free to move in a free movement direction during retraction of the headgear, and when the core member is pulled in a direction opposite to the free movement direction to elongate the headgear the lock member creates an angled path for the core member, increasing friction between the lock member and the core member;
• wherein the directional lock arrangement is a modular adjustment assembly.