Head harness for a respiratory mask

A head harness for a respiratory mask having:

• at least one expandable strap whose ends are connected to the mask and which has an element inflatable by pressurized gas for lengthening the strap to a predetermined size, sufficient to position it over the head of a user, and, in a housing,
• valve means comprising:
• a manually actuatable inflation valve having a rest condition into which it is biased by return means, wherein it vents an internal volume of said housing to atmosphere, and an actuated condition wherein it admits pressurized gas from an external source to said internal volume, and
• a selection valve optionally settable in at least two conditions, constructed to freely communicate said internal volume with said inflatable element in one of its said conditions and to prevent the pressure in said inflatable element from decreasing beyond a predetermined value above the pressure prevailing in said internal volume when in another one of its said conditions.

Safety apparatus for use in an airplane or the like comprising:

• mask means adapted to be fit against the face of a person and including structure presenting, when so fitted, a chamber adjacent the nose and mouth region of said person for the reception of a breathable gas mixture;
• means for delivery of said breathable gas mixture to said chamber, including means operably coupled with said mask means for delivery of pressurized oxygen thereto;
• an extensible, inflatable strap element operably connected with said mask means and extendable from a fully deflated position corresponding to a relatively low pressure therewithin which is substantially ambient pressure to a fully inflated position corresponding to full inflation pressure therewithin, and
• inflation control means operatively interconnecting said oxygen delivery means and said strap element, comprising manually controlled structure for selective inflation of the strap element to said full inflation pressure in order to extend the strap element to said fully inflated position to permit fitting thereof over the head of the person, and for deflation of the element to engage the head of the person to hold the mask in said fitted position, said inflation control means further including inflation level-maintaining means for selectively establishing and maintaining the level of inflation of the strap element at an intermediate gas pressure less than said full inflation pressure and greater than said relatively low pressure, said inflation level-maintaining means having structure for maintaining said intermediate gas pressure within said strap element without manual manipulation of said inflation control means.

A respiratory mask-fast donning head harness equipment for use in an airplane, comprising:

• a mask having an oro-nasal face cover adapted to be applied against the face of a user and a housing containing a demand regulator and defining, with said face cover, a chamber for the reception of a respiratory gas delivered by a demand regulator, means for delivery of said respiratory gas to said chamber, including means operably coupled with said mask means for delivery of pressurized oxygen thereto, and a demand regulator to form the respiratory gas;
• an extensible harness, having inflatable strap means operably connected with said mask and extendable from a fully deflated position corresponding to a relatively low pressure therewithin which is substantially ambient pressure to a fully inflated position corresponding to full inflation pressure therewithin, and
• inflation control means carried by said face cover, operatively interconnecting said oxygen delivery means and said strap means, comprising a manually controlled structure for selective inflation of the strap means to said full inflation pressure in order to extend the strap means to said fully inflated position to permit fitting thereof over the head of the person, and for deflation of the strap means to engage the head of the person to hold the mask in said fitted position, said inflation control means further including inflation level-maintaining means for selectively establishing and maintaining the level of inflation of the strap means at a residual gas pressure less than said full inflation pressure and greater than said relatively low pressure, said inflation level-maintaining means being arranged for maintaining said residual gas pressure within said strap means without manual manipulation of said inflation control means.

Safety apparatus for use in an airplane or the like, comprising:

• mask means adapted to be fit against the face of a person and including structure presenting, when so fitted, a chamber adjacent a nose and mouth region of said person for the reception of a breathable gas mixture;
• means for delivery of said breathable gas mixture to said chamber, including means operably coupled with said mask means for delivery of pressurized oxygen thereto;
• an extensible, inflatable strap element operably connected with said mask means;
• and
• inflation control means operatively interconnecting said oxygen delivery means and said strap element for selective, oxygen flow induced shifting of the strap element between an extended position permitting ready donning of the mask and retracted position wherein the strap element tightly engages the head of said person and the mask means is caused to tightly engage the wearer's face,
• said inflation control means further including comfort control structure for selectively establishing and maintaining the strap element at an intermediate pressure between the pressure therein at said extended and retracted positions thereof wherein the pressure exerted by the strap element against the wearer's head is lessened as compared with the pressure exerted thereby in said retracted position,
• said comfort structure having means for maintaining said intermediate strap pressure without manual manipulation of said inflation control means.