MASK WITH GUSSET
A mask system for delivering air to a user includes a suspension mechanism to allow relative movement between a face-contacting cushion and a mask shell. The suspension mechanism also provides a predetermined force to the cushion that is a function of mask pressure, displacement of the cushion or both.
1 . A breathable gas mask arrangement, comprising:
a mask shell having a portion adapted to receive a supply of pressurized breathable gas and a user side;
a gusset portion having a first side attached to the user side of the shell and having a second side;
a cushion having a first portion constructed and arranged to attach to the second side of the gusset portion and a second portion constructed and arranged to contact a user's face in use and provide a seal between the mask arrangement and the user's face; and
a headgear constructed and arranged to attach the mask shell to the user;
wherein, the gusset portion is constructed and arranged such that it can expand and contract to alter a distance between the mask shell and the cushion, an interior of the gusset portion being exposed to the supply of pressurized breathable gas and having a projected area on the user's face A g which is greater than an area A c of contact of the cushion with the user's face such that the supply of pressurized breathable gas acting on the area A g provides a component of a contact force F c of the cushion on the user's face, and a ratio of A g /A c is at least 1.30.
2 . A breathable gas mask arrangement as in claim 1 , wherein the ratio of A g /A c is in a range of 1.50 to 5.00.
3 . A breathable gas mask arrangement as in claim 2 , wherein the ratio of A g /A c is in a range of 2.00 to 4.00.
4 . A breathable gas mask arrangement as in claim 3 , wherein the ratio of A g /A c is in a range of 2.25 to 3.50.
5 . A breathable gas mask arrangement as in claim 1 , wherein the gusset portion can expand and contract to alter the distance between the mask shell and the cushion by at least 15 mm.
6 . A breathable gas mask arrangement as in claim 5 , wherein the gusset portion can expand and contract to alter the distance between the mask shell and the cushion by at least 20 mm.
7 . A breathable gas mask arrangement as in claim 1 , wherein the gusset portion includes a single gusset having a flexible sidewall with a generally triangular cross-section when not exposed to the supply of pressurized breathable gas that balloons to a generally rounded cross-section when exposed to the supply of pressurized breathable gas.
8 . A breathable gas mask arrangement as in claim 7 , wherein the gusset portion includes a plurality of interconnected gussets having flexible sidewalls with generally triangular cross-sections when not exposed to the supply of pressurized breathable gas that balloon to generally rounded cross-sections when exposed to the supply of pressurized breathable gas.
9 . A breathable gas mask arrangement as in claim 1 , wherein the gusset portion includes a plurality of sequentially interconnected steps moving from larger to smaller in area between the first and second sides of the gusset portion, respectively.
10 . A breathable gas mask arrangement as in claim 1 , wherein the mask shell includes an axially extending cylinder portion and the gusset portion is in the form of a piston axially slideably engaged with the cylinder portion of the mask shell.
11 . A breathable gas mask arrangement as in claim 10 , and further including a spring engaged between the mask shell and the piston to apply a retracting force between the mask shell and the piston.
12 . A breathable gas mask arrangement as in claim 11 , wherein the mask shell includes a stop portion for engaging the piston to limit axial movement of the piston.
13 . A breathable gas mask arrangement as in claim 1 , wherein the gusset portion includes a plurality of interconnected gussets, at least two of the gussets having differently sized areas exposed to the supply of pressurized breathable gas.
14 . A breathable gas mask arrangement as in claim 1 , wherein the gusset portion includes a sidewall having a thickened cross-section at a base of the sidewall.
15 . A breathable gas mask arrangement as in claim 14 , wherein the thickened portion has 20 a generally uniform thickness.
16 . A breathable gas mask arrangement as in claim 14 , wherein the gusset portion includes a sidewall having a cross-sectional thickness tapering from a thickened base portion to a thinner portion.
17 . A breathable gas mask arrangement as in claim 1 , and further including a generally rigid backstop attached to the mask shell for contacting a first sidewall portion of the gusset portion to limit movement of the first sidewall portion.
18 . A breathable gas mask arrangement as in claim 17 , wherein the generally rigid backstop extends around substantially an entire periphery of the gusset portion.
19 . A breathable gas mask arrangement as in claim 18 , and further including a generally rigid second backstop attached to the mask shell for contacting a second sidewall portion of the gusset portion to limit movement of the second sidewall portion.
20 . A breathable gas mask arrangement as in claim 1 , wherein the mask shell further includes a baffle disposed in an interior of the mask shell between a mask gas intake and a mask exhaust vent to deflect gas from the intake from directly flowing to the exhaust vent.
21 - 124 . (canceled)