A respiratory mask assembly for use in the delivery of non-invasive positive airway pressure to a user. The assembly includes a rigid shell having a channel portion defined by an inner wall, an outer wall and a channel floor, a face-contacting cushion acting to space the shell away from the user's face and a sealing tab extending from the cushion to engage a portion of the shell to provide a continuous airtight seal between the cushion and the shell. A retaining ring within the mask assembly is configured to secure the cushion to the shell. The retaining ring has a first portion including at least one clip configured to pass through at least one slot portion such that an underside surface of the at least one clip engages a section of the shell when the retaining ring is positioned within the channel.
1. A respiratory mask assembly for use in the delivery of non-invasive positive airway pressure to a user, comprising:
a substantially rigid shell including a plurality of receiving portions;
a cushion detachably connected to the shell, said cushion having a retaining channel, a retaining lip adjacent the retaining channel, and a sealing portion extending from the cushion to engage a portion of the shell to provide a continuous airtight seal between the cushion and the shell; and
a retaining ring to secure the cushion to the shell, the retaining ring being received within the retaining channel of the cushion prior to engagement with the shell to form a cushion and retaining ring sub-assembly, said retaining ring having a plurality of projecting engagement members configured to engage a respective one of the receiving portions of the shell when the cushion and retaining ring sub-assembly is assembled with the shell along a push-on direction, wherein at least a portion of the retaining channel extends in a radial direction of the cushion relative to the push-on direction.
2. The respiratory mask assembly of claim 1 , wherein the projecting engagement members include at least two clip members.
3. The respiratory mask assembly of claim 1 , wherein the shell further comprises:
a base portion defining a cavity with a rear opening;
an air inlet tube connected to the shell and having a port opening to an interior to supply breathable gas from a pressurized supply to an interior of the respiratory mask assembly; and
at least one gas washout vent including a plurality of holes to exhaust gases from the respiratory mask assembly.
4. The respiratory mask assembly of claim 1 , wherein a portion of the cushion is clamped between the shell and the retaining ring.
5. The respiratory mask assembly of claim 1 , wherein at least a portion of the retaining ring has a generally L-shaped cross-sectional configuration.
6. A method for securing a cushion and shell in a respiratory mask assembly, comprising:
providing a shell, a cushion and a retaining ring, the retaining ring including a plurality of projecting engagement portions and the shell including a plurality of receiving portions;
engaging a portion of the retaining ring between a channel portion and a retaining lip of the cushion to provide a cushion and retaining ring sub-assembly;
aligning the cushion and retaining ring sub-assembly with respect to the shell for movement along a push-on direction; and
engaging the projecting engagement portions of the cushion and retaining ring sub-assembly with the receiving portions of the shell to secure the cushion and retaining ring sub-assembly to the shell, wherein at least an upper portion of the retaining ring extends in a radial direction relative to the push-on direction.
7. The method of claim 6 , further comprising clamping a portion of the cushion against the shell upon engagement between the projecting engagement portions and the receiving portions of the shell, to provide a continuous airtight seal between the cushion and the shell.
8. The method of claim 6 , wherein the retaining ring has at least one portion having a generally L-shaped cross-sectional configuration.
9. A respiratory mask assembly for use in the delivery of non-invasive positive airway pressure to a user, comprising:
a substantially rigid shell including a plurality of receiving portions,
a cushion provided to the shell, said cushion having a retaining channel, a retaining lip adjacent the retaining channel, and a sealing portion extending from the cushion to engage a portion of the shell to provide a continuous airtight seal between the cushion and the shell; and
a retaining ring configured to secure the cushion to the shell, the retaining ring being provided within the retaining channel of the cushion and having a first portion including a plurality of projecting engagement portions configured to engage with the receiving portions of the shell, wherein the retaining ring has at least one portion with a generally L-shaped cross-sectional configuration.
10. The respiratory mask assembly of claim 9 , wherein a portion of the cushion is clamped between the retaining ring and the shell.
11. The respiratory mask assembly of claim 9 , wherein the L-shaped cross-sectional configuration includes a first leg oriented generally along a push-on direction of the retaining ring relative to the shell, and a second leg portion provided within the retaining channel and oriented generally transverse to the push-on direction.