NASAL MASK SYSTEM
A mask system includes a frame ( 20 ) adapted to attach headgear, a sealing arrangement ( 40 ) releasably connectable to the frame, and an elbow ( 70 ) provided to the sealing arrangement and adapted to be connected to an air delivery tube that delivers breathable gas to the patient. The sealing arrangement defines a breathing chamber and is adapted to form a seal with the patient's face. The sealing arrangement includes structure ( 50 ) to establish a positive connection with the frame and with the elbow.
1 . A nasal mask defining a breathing chamber for the delivery of a supply of gas at positive pressure to the airways of a patient, the nasal mask including a sidewall, and a cushion located adjacent the sidewall at a rear side of the nasal mask, a rearward sealing surface of the cushion has a contour in a top lip region that is formed with a concave curvature to have a shape that is complementary to a top lip region of a person, the contour of the rearward surface of the cushion is constructed and arranged to extend in use along respective left and right sides of the nose from a nasal bridge region of a person located adjacent the joint between the nasal bone and the cartilage to respective left and right nasal corner regions of a person adjacent the left and right naso-labial creases, the contour of the rearward sealing surface of the cushion is further adapted to extend along the top lip of a person from the left side of the nose to the right side of the nose,
the cushion includes a relatively thick backup band formed from a resilient flexible material and extending from the sidewall to form respective cantilevers in a top lip region, a corner region and a side of nose region of the cushion, said cantilevers each having a length and a thickness and said cantilevers defining respective lip region, corner region and side of nose region stiffnesses, wherein the corner region cantilever is stiffer than the top lip region cantilever in a direction normal to the plane of the face,
the cushion further includes a relatively thin facial flap, the facial flap is inwardly curving and extends around the perimeter of the cushion to define the rearward sealing surface of the cushion, an inner edge of the facial flap defines an orifice through which a portion of a nose of the patient passes in use.
2 . A nasal mask according to claim 1 , wherein the backup band in the region of the side of the nose has a curved surface that is arranged to provide in use a force in a first direction into the plane of the face, and to provide a force in a second lateral direction onto the side of the nose along a region that extends from the nasal bone to the cartilage.
3 . A nasal mask according to claim 1 , wherein a length of the side of nose cantilever is greater than a length of the corner of nose cantilever.
4 . A nasal mask according to claim 1 , wherein a thickness of the corner of nose cantilever is thicker than a corresponding thickness of the top lip region cantilever.
5 . A nasal mask according to claim 1 , wherein at least one cantilever is a double cantilever.
6 . A nasal mask according to claim 1 , wherein at least one cantilever is a triple cantilever.
7 . A nasal mask according to claim 1 , wherein at least one cantilever is constructed and arranged to bend about two points.
8 . A nasal mask according to claim 1 , wherein at least one cantilever defines first and second bending points or regions.
9 . A nasal mask according to claim 1 , wherein at least one cantilever defines first, second and third bending points or regions.
10 . A nasal mask according to claim 1 , wherein at least one cantilever is constructed and arranged to direct a first force in a first direction and a second force in a second direction.
11 . A nasal mask according to claim 10 , wherein the at least one cantilever provides the first force in a direction normal to a region of the face adjacent the side of the nose, and the second force in a direction normal to the side of the nose.
12 . A nasal mask according to claim 1 , wherein corresponding respective left and right portions of the backup band are constructed and arranged to splay outwardly in use to accommodate a wider nose.
13 . A nasal mask according to claim 1 , wherein at least one cantilever is formed in one piece with a sidewall of the mask.
14 . A nasal mask according to claim 1 , wherein at least one cantilever is a curved cantilever.
15 . A nasal mask according to claim 1 , wherein at least one cantilever extends radially a distance further than a radial extent of an adjacent sidewall portion.
16 . A nasal mask according to claim 1 , wherein at least one cantilever overhangs an adjacent sidewall portion.
17 . A nasal mask according to claim 1 , wherein flexure of a cantilever causes flexure of an adjacent sidewall portion.
18 . A nasal mask according to claim 1 , wherein a sidewall portion adjacent a cantilever is adapted to flex in response to flexure of the cantilever.
19 . The nasal mask according to claim 1 , wherein an inner edge of a left portion of the backup band in the region of the nasal bridge is spaced a distance from an inner edge of a right portion of the backup band in the region of the nasal bridge.
20 . The nasal mask according to claim 19 , wherein the distance is no greater than about 25-30 mm.