Breathing assistance apparatus

Abstract

A breathing assistance apparatus is disclosed, for use with delivery of respiratory gases to a patient. The breathing assistance apparatus includes a patient interface, having a body section adapted to cover the nose, or nose and mouth of a patient and a sealing interface. The sealing interface includes at least an outer sealing member. The outer sealing member is adapted to attach to the body section in a sealing manner and has a substantially thin section in at least its nasal bridge region. The thin section is substantially thinner than the rest of the outer sealing member. The patient interface comprises a mask body and a seal assembly. The seal assembly includes a flexible seal, and a rigid seal clip, the seal assembly being removably attached to the mask body via the rigid seal clip. The mask body and rigid seal clip are profiled to match the contours of a user's face so that the seal has a substantially constant wall depth.

1 . (canceled) 
     
     
         2 . A mask assembly for use as part of an apparatus for supplying a flow of respiratory gases to a user comprising:
 a mask body, said mask body including an inlet through which said flow of respiratory gases are provided to the interior of said mask body, the inlet adapted to in use be connected to a gases conduit,   a mask seal assembly comprising a flexible seal and a rigid clip,   said seal having a first side and a second side, the first side of said seal being shaped to approximately match the contours of a user's face and in use substantially seal against a user's face, said second side adapted for attachment to said clip,   said clip being shaped to generally follow the contours of a user's face, and a rear periphery of said mask body also being correspondingly shaped to generally follow the contours of a user's face,   said clip providing a rigid interface extending substantially the full perimeter or periphery of the mask seal assembly for releasably attaching the mask seal assembly to the mask body, and   one of the clip or the mask body having at least one recess and tile other one of the mask body or the clip having a series of bumps, interference between the bumps and the clip or the mask body during attachment of the clip to the mask body providing a positive snap type engagement of the clip to the mask body as the bumps locate in the at least one recess, and   one of the clip or the mask body having a lead in section providing a gradual deflection of the clip, or the mask body, or both, when attaching the clip to the mask body, the lead-in section extending substantially the full perimeter of the clip or the mask body.   
     
     
         3 . The mask assembly as claimed in  claim 2  wherein the seal has a wall portion extending around the periphery of the seal assembly between the first and second sides, the wall being approximately or substantially constant in depth. 
     
     
         4 . The mask assembly as claimed in  claim 2  wherein the recesses are located immediately behind the lead-in section. 
     
     
         5 . The mask assembly as claimed in  claim 2  wherein the lead in section has a length to height ratio of 3 to 7. 
     
     
         6 . The mask assembly as claimed in  claim 2  wherein a cross section of the mask seal assembly at the clip has a width to height ratio of 1.5 to 2. 
     
     
         7 . The mask assembly as claimed in  claim 6  wherein the clip is adapted to disengage the seal assembly from the mask body when squeezed at opposite perimeter portions at positions absent of a said bump. 
     
     
         8 . The mask assembly as claimed in  claim 2  wherein the corresponding shape of the clip and the mask body provides for automatic correction of angular misalignment between the seal assembly and the mask body when fitting the seal assembly to the mask body. 
     
     
         9 . The mask assembly as claimed in  claim 2  wherein the seal assembly attaches to the mask body in a sealed engagement, a first bearing surface of the seal bearing against a corresponding second bearing surface of the mask body in a butting engagement. 
     
     
         10 . The mask assembly as claimed in  claim 9  wherein the first bearing surface comprising a raised rim, in use the raised rim being compressed against the second bearing surface. 
     
     
         11 . The mask assembly as claimed in  claim 2  wherein the clip has at least one wing portion, the wing portion providing a gripping flange to assist with removing the seal assembly from the mask body. 
     
     
         12 . The mask assembly as claimed in  claim 2  wherein the lead-in section extends at least 50% of the full perimeter of the seal assembly clip or the mask body. 
     
     
         13 . The mask assembly as claimed in  claim 2  wherein the mask assembly further comprises headgear for securing the mask assembly to the head of a user. 
     
     
         14 . The mask assembly as claimed in  claim 2  wherein the mask assembly further comprises an inner cushion around the outer periphery of the mask body between the mask body and the first side of the seal.