U.S. patent application number 15/865784 was filed with the patent office on 2018-05-24 for mask system.
The applicant listed for this patent is ResMed Limited. Invention is credited to Amal Shirley AMARASINGHE, Timothy Tsun-Fai FU, Michael Andrew JONES, Perry David LITHGOW, Jim SAADA, Fiachra Marcus SWEENEY.
Application Number | 20180140791 15/865784 |
Document ID | / |
Family ID | 33419177 |
Filed Date | 2018-05-24 |
United States Patent
Application |
20180140791 |
Kind Code |
A1 |
JONES; Michael Andrew ; et
al. |
May 24, 2018 |
MASK SYSTEM
Abstract
A mask system for treating sleep disordered breathing. The mask
system includes headgear and a combination shell and cushion. A
plurality of ribs provide rigidity to the combination shell and
cushion and are formed integrally with the combination shell and
cushion. The mask system also includes a frame shaped and adapted
to be removably mounted on the combination shell and cushion. The
frame has a plurality of headgear anchor points. A retaining ring
is positioned adjacent the front aperture. In addition, a rotatable
elbow has a proximal end, a distal end and circumferentially
equi-spaced diametrically opposed tongues with undercuts. The
proximal end is adapted to pass through the retaining ring. The
distal end is adapted to engage an air delivery tube, and the
undercuts are adapted to engage the retaining ring. Also, a seal
allows rotation of the rotatable elbow relative to the combination
shell and cushion.
Inventors: |
JONES; Michael Andrew;
(Sydney, AU) ; AMARASINGHE; Amal Shirley; (Sydney,
AU) ; FU; Timothy Tsun-Fai; (Sydney, AU) ;
LITHGOW; Perry David; (Sydney, AU) ; SAADA; Jim;
(Sydney, AU) ; SWEENEY; Fiachra Marcus; (Dublin,
IE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ResMed Limited |
Bella Vista |
|
AU |
|
|
Family ID: |
33419177 |
Appl. No.: |
15/865784 |
Filed: |
January 9, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13957475 |
Aug 2, 2013 |
9895503 |
|
|
15865784 |
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|
|
|
12654595 |
Dec 23, 2009 |
8505535 |
|
|
13957475 |
|
|
|
|
10555301 |
Feb 1, 2006 |
7861715 |
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PCT/AU2004/000563 |
Apr 30, 2004 |
|
|
|
12654595 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 16/0057 20130101;
A61M 16/0816 20130101; A61M 16/0683 20130101; A61M 16/06 20130101;
A61M 2210/0618 20130101; A61M 16/0858 20140204; A61M 16/0616
20140204; A62B 18/02 20130101; A61M 16/0611 20140204; A61M 16/0633
20140204; A61M 16/0825 20140204 |
International
Class: |
A61M 16/00 20060101
A61M016/00; A62B 18/02 20060101 A62B018/02; A61M 16/06 20060101
A61M016/06; A61M 16/08 20060101 A61M016/08 |
Foreign Application Data
Date |
Code |
Application Number |
May 2, 2003 |
AU |
AU 2003902098 |
Mar 26, 2004 |
AU |
AU 2004901648 |
Claims
1-20. (canceled)
21. A mask system for treating sleep disordered breathing, the mask
system comprising: headgear with a plurality of headgear straps; a
combination shell and cushion having a sealing structure and a
support structure, the sealing structure having a face contacting
side configured to create a seal with a face of a patient, the
support structure including a front aperture and a series of vent
orifices; a plurality of ribs configured to provide rigidity to the
combination shell and cushion, the plurality of ribs being formed
integrally with the combination shell and cushion; a frame shaped
and adapted to be removably mounted on the combination shell and
cushion, the frame comprising a plurality of headgear anchor
points; a retaining ring positioned adjacent the front aperture;
and a rotatable elbow with a proximal end, a distal end and
circumferentially equi-spaced diametrically opposed tongues with
undercuts, the proximal end being adapted to pass through the
retaining ring, the distal end being adapted to engage an air
delivery tube, and the undercuts being adapted to engage the
retaining ring; and a seal that allows rotation of the rotatable
elbow relative to the combination shell and cushion.
22. The mask system of claim 21, wherein the combination shell and
cushion has a dual wall construction.
23. The mask system of claim 21, wherein the face contacting side
of the sealing structure has a shot blasted finish.
24. The mask system of claim 21, wherein each of the plurality of
ribs has a thickness of approximately 2-3 mm.
25. The mask system of claim 21, wherein the frame comprises four
headgear anchor points.
26. The mask system of claim 21, wherein at least one of the
plurality of headgear straps is configured to be threaded through a
corresponding one of the headgear anchor points.
27. The mask system of claim 21, wherein the distal end of the
rotatable elbow has a swivel connection.
28. The mask system of claim 21, wherein the distal end of the
rotatable elbow does not have a swivel connection.
29. The mask system of claim 21, wherein the rotatable elbow is
removable from the combination shell and cushion.
30. The mask system of claim 21, wherein the frame is configured to
be pushed into a fixed position on the combination shell and
cushion from a front of the combination shell and cushion.
31. The mask system of claim 21, wherein the mask system does not
comprise a forehead support.
32. The mask system of claim 21, wherein the frame is made of
polycarbonate material.
33. The mask system of claim 21, wherein the rotatable elbow
comprises a braking system that permits the rotatable elbow to
remain in a set position.
34. The mask system of claim 21 further comprising the air delivery
tube.
35. The mask system of claim 21 comprising the air delivery tube,
wherein the combination shell and cushion has a dual wall
construction, wherein the face contacting side of the sealing
structure has a shot blasted finish, wherein each of the plurality
of ribs has a thickness of approximately 2-3 mm, wherein the frame
comprises four headgear anchor points, wherein at least one of the
plurality of headgear straps is configured to be threaded through a
corresponding one of the headgear anchor points, wherein the distal
end of the rotatable elbow has a swivel connection, wherein the
distal end of the rotatable elbow does not have a swivel
connection, wherein the rotatable elbow is removable from the
combination shell and cushion, wherein the frame is configured to
be pushed into a fixed position on the combination shell and
cushion from a front of the combination shell and cushion, wherein
the mask system does not comprise a forehead support, wherein the
frame is made of polycarbonate material, and wherein the rotatable
elbow comprises a braking system that permits the rotatable elbow
to remain in a set position.
36. A mask system for treating sleep disordered breathing, the mask
system comprising: headgear with a plurality of headgear straps; a
combination shell and cushion having a sealing structure and a
support structure, the sealing structure having a face contacting
side configured to create a seal with a face of a patient, the
support structure including a front aperture and a series of vent
orifices; a plurality of ribs configured to provide rigidity to the
combination shell and cushion, the plurality of ribs being formed
integrally with the combination shell and cushion; a frame shaped
and adapted to be removably mounted on the support structure of the
combination shell and cushion, the frame comprising a plurality of
headgear anchor points; a retaining ring with a front flange and a
rear flange defining a channel, the retaining ring being adapted to
be positioned adjacent the front aperture on the support structure
so that the rear flange engages the support structure; and a
rotatable elbow with a proximal end that extends through the
retaining ring so that the proximal end passes through the front
aperture in the support structure when the rotatable elbow is
secured to the combination shell and cushion; and a seal that
allows rotation of the rotatable elbow relative to the combination
shell and cushion.
37. The mask system of claim 36, wherein a portion of the support
structure is exposed through the frame.
38. The mask system of claim 36, wherein the frame comprises four
headgear anchor points.
39. The mask system of claim 36, wherein at least one of the
plurality of headgear straps is configured to be threaded through a
corresponding one of the headgear anchor points.
40. The mask system of claim 36, wherein the rotatable elbow is
removable from the combination shell and cushion.
41. The mask system of claim 36, wherein the frame is made of
polycarbonate material and is configured to be pushed into a fixed
position on the combination shell and cushion from a front of the
combination shell and cushion.
42. The mask system of claim 36, wherein the mask system does not
comprise a forehead support.
43. The mask system of claim 36, wherein the frame is made of
polycarbonate material.
44. The mask system of claim 36, wherein a portion of the support
structure is exposed through the frame, wherein the frame comprises
four headgear anchor points, wherein at least one of the plurality
of headgear straps is configured to be threaded through a
corresponding one of the headgear anchor points, wherein the
rotatable elbow is removable from the combination shell and
cushion, wherein the frame is configured to be pushed into a fixed
position on the combination shell and cushion from a front of the
combination shell and cushion, wherein the mask system does not
comprise a forehead support, and wherein the frame is made of
polycarbonate material.
45. A mask system for treating sleep disordered breathing, the mask
system comprising: headgear with a plurality of headgear straps; a
combination shell and cushion having a sealing structure and a
support structure, the sealing structure having a face contacting
side configured to create a seal with a face of a patient, the
support structure including a front aperture and an annular rim
around the front aperture; a frame shaped and adapted to be
removably mounted on the support structure of the combination shell
and cushion, the frame being configured so that the headgear is
movable with the frame; a retaining ring positioned adjacent the
front aperture; and a rotatable elbow with a proximal end and a
distal end, the proximal end being adapted to pass through the
retaining ring to engage the annular rim to form a seal that allows
rotation of the rotatable elbow relative to the combination shell
and cushion.
46. The mask system of claim 45, wherein the face contacting side
of the sealing structure has a shot blasted finish.
47. The mask system of claim 45, wherein the distal end of the
rotatable elbow does not have a swivel connection.
48. The mask system of claim 45, wherein the rotatable elbow is
removable from the combination shell and cushion.
49. The mask system of claim 45, wherein the frame is made of
polycarbonate material and is configured to be pushed into a fixed
position on the combination shell and cushion from a front of the
combination shell and cushion.
50. The mask system of claim 45, wherein the mask system does not
comprise a forehead support.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/957,475, filed Aug. 2, 2013, now pending, which is a
continuation of U.S. application Ser. No. 12/654,595, filed Dec.
23, 2009, now U.S. Pat. No. 8,505,535, which is a divisional of
U.S. application Ser. No. 10/555,301, filed Nov. 2, 2005, now U.S.
Pat. No. 7,861,715, which is the U.S. national phase of
international application PCT/AU2004/000563, filed Apr. 30, 2004,
which designated the U.S. and claims priority to AU 2003902098,
filed May 2, 2003, and AU 2004901648, filed Mar. 26, 2004, the
entire contents of each of which are hereby incorporated by
reference.
FIELD OF THE INVENTION
[0002] The invention relates to a mask system for use with positive
pressure ventilation of sleep disordered breathing. In particular,
the invention relates to a low cost mask system.
BACKGROUND
[0003] Obstructive Sleep Apnea (OSA) is a condition characterised
by repetitive obstruction of the upper airway often resulting in
oxygen desaturation and arousals from sleep. The classic daytime
manifestation is excessive sleepiness but other symptoms such as
unrefreshing sleep, poor concentration and fatigue are commonly
reported (Sleep-Related Breathing Disorders in Adults-AASM Task
Force, Sleep 22, 1999).
[0004] The use of nasal continuous positive airway pressure (CPAP)
to treat OSA was taught by Sullivan in U.S. Pat. No. 4,944,310.
Other developments are taught in U.S. Pat. Nos. 5,704,345;
6,029,665 and 6,363,933.
[0005] Nasal CPAP systems typically comprise a flow generator, air
tubing, and a patient interface (for example, a nasal mask). The
flow generator provides a supply of air at positive pressure.
[0006] A variety of mask systems are known for use in treating
sleep disordered breathing (SDB), such as the BUBBLE.RTM. mask,
MIRAGE.RTM., ULTRA MIRAGE.RTM., and MIRAGE VISTA.TM. masks, all
manufactured by ResMed Limited.
[0007] Another known mask is the Weinmann nasal mask.
[0008] A mask system typically comprises headgear and a mask
assembly. The headgear is used to hold and position the mask on the
face of a patient. The mask assembly typically comprises at least a
rigid shell and a soft face-contacting cushion. Some mask
assemblies also include elbows, vents, headgear clips, forehead
supports.
[0009] A number of cushions have been patented, for example see
U.S. Pat. Nos. 6,112,746; 6,357,441; 6,513,526; as have forehead
supports (See U.S. Pat. Nos. 6,119,693; 6,463,931; 6,520,182;
6,532,961), headgear connectors (U.S. Pat. No. 6,374,826), mask
ports (U.S. Pat. No. 6,439,230), and cushion clips (U.S. Pat. No.
6,412,487). For example, U.S. Pat. No. 6,513,526 discloses both
nasal and full face cushions. The contents of all these patents are
hereby incorporated by cross-reference.
[0010] Another known mask assembly the PAPILLION.TM. mask,
manufactured by MAP, Germany is shown in Austrian Design
Registrations #50770 and #50771 (and U.S. Design Pat. No. D484,237
and Australian Design Registration Application 2153/2002).
[0011] Since mask systems for treating sleep disordered breathing
have to be worn for several hours every night while a patient
sleeps, designers strive to make them comfortable. In particular,
they strive to attempt to eliminate the mask system being a source
of pressure sores on a patient's face.
[0012] A problem which can occur in prior art mask systems is that
there can be drag forces from the tube which when transferred
through the elbow can disrupt the seal of the cushion on the
face.
[0013] One solution to this problem is found in U.S. Pat. No.
6,039,044. It is an aspect of the invention to provide at least an
alternative solution to this problem.
[0014] A difficulty with some prior art mask assemblies is that
those which achieve a clinically effective seal while being
comfortable to wear each night at home can be expensive to
manufacture. Headgear can represent a significant proportion of the
cost of manufacturing a mask system. The manufacturing costs are
passed onto customers which leads to a more expensive mask assembly
for patients. This may in turn mean that fewer patients can afford
treatment. This may also mean that there can be a tendency for
clinics and hospitals to reuse masks among numerous patients.
Unless thorough hygiene systems are put in place to manage
cross-infection it is not advised that a mask be re-used by
different patients. In general, particularly in hospitals with the
advent of respiratory diseases such as SARS, it is desirable to
have a mask system which is cheap enough to be disposable.
[0015] It is a further aspect of the invention to provide a low
cost mask assembly for treating sleep disordered breathing.
[0016] It is a further aspect of the invention to provide a
disposable mask assembly for treating sleep disordered
breathing.
SUMMARY OF THE INVENTION
[0017] Throughout this specification and claims, a combination
shell and cushion will hereinafter be referred to as a
"shell/cushion". Whilst this is done for convenience, where ever
the expression "shell/cushion" appears it should be read as meaning
the combined shell and cushion.
[0018] In accordance with a first aspect of the invention, there is
provided a comfortable low cost mask system comprising headgear, a
combination shell/cushion, a frame, elbow and retaining ring.
[0019] In accordance with another aspect of the invention, there is
provided a low cost headgear.
[0020] In accordance with another aspect of the invention, there is
provided a comfortable shell/cushion which has a reduced tendency
to cause pressure points on a patient's face.
[0021] In one embodiment, a mask system for treating sleep
disordered breathing comprises headgear, a shell/cushion including
a channel adjacent a front aperture, a frame, an elbow including at
least one undercut on a proximal end and a retaining ring including
a rear flange adapted to be retainably insertable in the channel of
the shell/cushion and a front flange adapted to retainably engage
with the at least one undercut of the elbow.
[0022] There can be a thin walled section adjacent the channel of
the shell/cushion which is adapted to tear upon removal of the
elbow.
[0023] The elbow construction can help prevent separation of the
aperture from the retaining ring during normal use.
[0024] The elbow when separate from the mask can have a cylindrical
outlet.
[0025] The shell/cushion can include an annular flange which when
assembled with the elbow or said connection piece engages a rim of
said outlet to thereby suitably seal the outlet to said flange.
[0026] In another embodiment, a mask system for treating sleep
disordered breathing comprises headgear, a frame, and shell/cushion
including a frame-receiving channel defined by a front flange and a
rear flange, the front flange extending 75% to 100% of the way
around the perimeter of the shell/cushion, wherein the frame is
adapted to be removably insertable in the frame-receiving channel
of the shell/cushion.
[0027] This mask system can include at least a nasal bridge region
of the shell/cushion adapted to contact the nasal bridge region of
a patient. The rear flange of the nasal bridge region can be from 1
mm to 3 mm thick. The rear flange can be approximately 2 mm
thick.
[0028] In still another embodiment, a connection piece for
connecting a mask to a conduit which can carry an air flow to said
mask is provided. The connection piece includes an inlet and an
outlet and a passage wall to carry the air flow therebetween, the
connection piece including, in the vicinity of said outlet between
said outlet and said inlet, a vent wall extending away from the
passage wall, the vent wall including at least one aperture
therethrough.
[0029] The connection piece can be formed integrally with the mask.
Alternatively the connection piece can be formed separately of the
mask and can be joined or attached thereto.
[0030] The piece can be formed integrally with the conduit.
Alternatively the connection piece can be formed separate from the
conduit and can be joined or attached thereto.
[0031] The connection piece can be formed so that the outlet lies
at any appropriate angle to the inlet. Preferably said outlet lies
at an angle to the inlet which angle is in the range of 90.degree.
to 180.degree.. The connection piece can be a 90.degree. elbow.
[0032] The connection piece can include attachment structure to
attach the connection piece to the mask. The attachment structure
can include at least one snap-in undercut to engage a mating.
[0033] The attachment structure can releasably attach the
connection piece to the mask.
[0034] The attachment structure can include moveable portions on
which said snap-in undercuts are formed, the moveable portions
allowing said undercuts to disengage the flange.
[0035] The attachment structure can allow rotation of said
connection piece relative to said mask.
[0036] The connection piece can include a Luer port through the
passage wall, which can be on a side and/or the front of said
connection piece.
[0037] The vent wall can lay at an oblique angle to the air flow.
The angle is preferably in the range of 25.degree. to
155.degree..
[0038] The connection piece can include on its external surface a
recess having wall portions extending away from an external side of
said vent wall. The wall portions can diverge in a direction away
from said vent wall.
[0039] In yet another embodiment, a mask for treating sleep
disordered breathing includes a shell/cushion with an inner and
outer surface, a flange extending away from the outer surface and
surrounding the shell/cushion, the mask having an exoskeletal frame
having a shape which substantially matches the contours of the
flange so that it can be positioned adjacent the flange when the
shell/cushion is in a shape suitable for use by a patient, and
structure to hold said flange to the frame.
[0040] The structure to hold the flange to the frame can include
one or more apertures through the flange.
[0041] Rivets or other fixers can pass through said apertures to
hold the flange adjacent the frame.
[0042] The frame can be attached to headgear to position the mask
onto a patient's head.
[0043] The frame can include connection members connected to the
frame for cooperating therewith to sandwich the flange between said
connection members and the frame. The connection members can be
hinged to the frame, or connected to the frame by a flexible
member.
[0044] A second frame of a shape which substantially matches the
contours of the flange can be present, whereby said flange is
sandwiched between the first frame and the second frame.
[0045] The second frame, the flange and the first ring member can
be held together by rivets and/or fixers, etc.
[0046] The second frame can include rivets extending therefrom,
which can pass through the flange and the first frame.
Alternatively the first frame can include rivets extending
therefrom, which can pass through the flange and the second frame.
Another alternative is for the flange to include a first set of
rivets extending in a forward direction and a second set of rivets
extending in a rearward direction, the first set of rivets being
received in apertures through the first frame, the second set of
rivets being received in apertures through the second frame.
[0047] The rivets can be deformable at their free end, or the
aperture into which they protrude can be deformable.
[0048] The rivets can include an undercut so that the undercut can
pass through the apertures to hold components together.
[0049] Another embodiment of the invention provides a mask system
including head gear and mask as described above. This mask system
can include a connection piece as described above.
[0050] These another aspects will be described in or apparent from
the following detailed description of preferred embodiments.
BRIEF DESCRIPTION OF FIGURES
[0051] Embodiments of the present invention will now be described
by way of example only, with reference to the accompanying Figures,
in which:
[0052] FIG. 1 shows a perspective view of a mask system according
to an embodiment of the present invention;
[0053] FIG. 2 shows a front perspective view of a mask assembly
similar to that used in the system of FIG. 1, but having a
different shell/cushion;
[0054] FIG. 2A shows a front view of the mask assembly of FIG.
2;
[0055] FIG. 3 shows a side view of the mask assembly of FIG. 2;
[0056] FIG. 4 shows a rear view of the mask assembly of FIG. 2;
[0057] FIG. 5 shows a bottom view of the mask assembly of FIG.
2;
[0058] FIG. 6 shows a top view of the mask assembly of FIG. 2;
[0059] FIG. 7 shows an exploded view of the mask assembly of FIG.
2;
[0060] FIG. 8 shows a cross-section of the mask assembly of FIG.
2;
[0061] FIG. 9 shows a further cross-section of the mask assembly of
FIG. 2 superimposed over a side view;
[0062] FIG. 10 shows a front perspective view of another mask
assembly having the same shell/cushion used in FIG. 2, with a
different frame;
[0063] FIG. 11 shows an exploded view of another mask assembly near
the face of a patient having a frame similar to that used in FIG.
10 but with a shell/cushion similar to that used in FIGS. 1 and
7;
[0064] FIG. 12 shows a side view of the mask assembly of FIG. 11
including disposable headgear in use;
[0065] FIG. 13 illustrates a front elevation of a three point frame
as used in the mask assembly of FIG. 2;
[0066] FIG. 14 illustrates a cross section through lines XIV-XIV
the frame of FIG. 13;
[0067] FIG. 15 illustrates a right side elevation of the frame of
FIG. 13;
[0068] FIG. 16 illustrates a plan view of the frame of FIG. 13;
[0069] FIG. 17 illustrates an underneath view of the frame of FIG.
13;
[0070] FIG. 18 illustrates a cross section showing detail Z of FIG.
14;
[0071] FIG. 19 illustrates a left hand side perspective view of the
frame of FIG. 13;
[0072] FIG. 20 illustrates a right hand side perspective view of
the frame of FIG. 13;
[0073] FIG. 21 illustrates a front elevation of a five point frame
as used in the mask assembly of FIGS. 10 and 11;
[0074] FIG. 22 illustrates a cross section through lines the frame
of FIG. 21;
[0075] FIG. 23 illustrates a left side elevation of the frame of
FIG. 21;
[0076] FIG. 24 illustrates an underneath view of the frame of FIG.
21;
[0077] FIG. 25 illustrates a plan view of the frame of FIG. 21;
[0078] FIG. 26 illustrates a front elevation of a retaining
ring;
[0079] FIG. 27 illustrates a cross section through the lines
XXVII-XXVII of the retaining ring of FIG. 26;
[0080] FIG. 28 illustrates a side elevation of the retaining ring
of FIG. 26;
[0081] FIG. 29 illustrates a perspective view of the retaining ring
of FIG. 26;
[0082] FIG. 30 illustrates a front elevation of a connection piece
or elbow;
[0083] FIG. 31 illustrates a right side view of the elbow of FIG.
30;
[0084] FIG. 32 illustrates a cross section through the line
XXXII-XXXII of the elbow of FIG. 30;
[0085] FIG. 33 illustrates a cross section through the line
XXXIII-XXXIII of the elbow of FIG. 30;
[0086] FIG. 34 illustrates a plan view of the elbow of FIG. 30;
[0087] FIG. 35A illustrates a lower rear perspective view of the
elbow of FIG. 30;
[0088] FIG. 35B illustrates an upper front perspective view of the
elbow of FIG. 30;
[0089] FIG. 36 illustrates detail X of the cross section of FIG.
33;
[0090] FIG. 37 illustrates detail Z of the cross section of FIG.
32;
[0091] FIG. 38 illustrates a front elevation of a connection piece
or elbow for single use;
[0092] FIG. 39 illustrates a left side view of the elbow of FIG.
38;
[0093] FIG. 40 illustrates a cross section through the line XL-XL
of the elbow of FIG. 38;
[0094] FIG. 41 illustrates a plan view of the elbow of FIG. 38;
[0095] FIG. 42 illustrates a cross section through the line
XLII-XLII of the elbow of FIG. 38;
[0096] FIG. 43 illustrates a lower rear perspective view of the
elbow of FIG. 38;
[0097] FIG. 44 illustrates an upper front perspective view of the
elbow of FIG. 38;
[0098] FIG. 45 illustrates detail Z of the cross section of FIG.
40;
[0099] FIG. 46 illustrates detail X of the cross section of FIG.
42;
[0100] FIG. 47 illustrates a front elevation of a shell/cushion
having four points or channels spaced around the periphery to
attach a frame;
[0101] FIG. 48 illustrates a right side elevation of the
shell/cushion of FIG. 47;
[0102] FIG. 49 illustrates a cross section through the line
XLIX-XLIX of the shell/cushion of FIG. 47;
[0103] FIG. 50 illustrates a plan view of the shell/cushion of FIG.
47;
[0104] FIG. 51 illustrates a cross section through the line LI-LI
of the shell/cushion of FIG. 47;
[0105] FIG. 52 illustrates detail Z of the cross section of FIG.
49;
[0106] FIG. 53 illustrates a cross section through line LIII-LIII
of the shell/cushion of FIG. 48;
[0107] FIG. 54 illustrates a lower rear perspective view of the
shell/cushion of FIG. 47;
[0108] FIG. 55 illustrates an upper front perspective view of the
shell/cushion of FIG. 47;
[0109] FIG. 56 illustrates a front elevation of a shell/cushion
having a continuous channel around the periphery to attach a
frame;
[0110] FIG. 57 illustrates a right side elevation of the
shell/cushion of FIG. 56;
[0111] FIG. 58 illustrates a cross section through the line
LVIII-LVIII of the shell/cushion of FIG. 56;
[0112] FIG. 59 illustrates a plan view of the shell/cushion of FIG.
56;
[0113] FIG. 60 illustrates an underneath view of the shell/cushion
of FIG. 56;
[0114] FIG. 61 illustrates a cross section through line LXI-LXI of
the shell/cushion of
[0115] FIG. 57;
[0116] FIG. 62 illustrates the side elevation of a mask assembly of
the shell/cushion of FIGS. 56 to 61, the frame of FIGS. 13 to 20
and the elbow of FIGS. 30 to 37;
[0117] FIG. 63 illustrates a cross section through the line
LXIII-LXIII of the mask assembly of FIG. 62;
[0118] FIG. 64 illustrates a cross section through the line
LXIV-LXIV of the mask assembly of FIG. 62;
[0119] FIG. 65 illustrates a cross section through the line LXV-LXV
of the mask assembly of FIG. 62;
[0120] FIG. 66 illustrates a cross section through the line
LXVI-LXVI of the mask assembly of FIG. 62;
[0121] FIG. 67 shows headgear in accordance with a disposable
embodiment of the invention;
[0122] FIG. 68A shows a shell/cushion with a bellows portion
demonstrating decoupling of the torque transfer between the elbow
and the cushion;
[0123] FIG. 68B shows the shell/cushion of FIG. 68A whereby the
bellows portion is in the action of decoupling torque;
[0124] FIG. 69 illustrates a front elevation of a frame;
[0125] FIG. 70 illustrates a right side elevation of the frame of
FIG. 69;
[0126] FIG. 71 illustrates a cross section through the line
LXXI-LXXI of the frame of
[0127] FIG. 69;
[0128] FIG. 72 illustrates a cross section through the line
LXXII-LXXII of the frame of FIG. 69;
[0129] FIG. 73 illustrates a cross section through the line
LXXIII-LXXIII of the frame of FIG. 69;
[0130] FIG. 74 illustrates a rear elevation of the frame of FIG.
69;
[0131] FIG. 75 illustrates in detail a portion from the cross
section of FIG. 71;
[0132] FIG. 76 illustrates in detail a portion from the cross
section of FIG. 72;
[0133] FIG. 77 illustrates a right side perspective view of the
frame of FIG. 69;
[0134] FIG. 78 illustrates a left side perspective view of the
frame of FIG. 69;
[0135] FIG. 79 illustrates a front elevation of a clip for use with
the frame of FIG. 69;
[0136] FIG. 80 illustrates a right side elevation of the frame of
FIG. 79;
[0137] FIG. 81 illustrates a cross section through the line
LXXXI-LXXXI of the frame of FIG. 79;
[0138] FIG. 82 illustrates a cross section through the line
LXXXII-LXXXII of the frame of FIG. 79;
[0139] FIG. 83 illustrates a cross section through the line
LXXXIII-LXXXIII of the frame of FIG. 79;
[0140] FIG. 84 illustrates a rear elevation of the frame of FIG.
79;
[0141] FIG. 85 illustrates in detail a portion from the cross
section of FIG. 82;
[0142] FIG. 86 illustrates in detail a portion from the cross
section of FIG. 83;
[0143] FIG. 87 illustrates a right side perspective view of the
frame of FIG. 79;
[0144] FIG. 88 illustrates a left side perspective view of the
frame of FIG. 79;
[0145] FIG. 89 illustrates a front view of an elbow according to
yet another embodiment of the present invention;
[0146] FIG. 90 illustrates a cross section through the line XC-XC
of the elbow of FIG. 89;
[0147] FIG. 91 illustrates a cross section through the line XCI-XCI
of the elbow of FIG. 89;
[0148] FIG. 92 illustrates a plan view of the elbow of FIG. 89;
[0149] FIG. 93 illustrates a cross section through the line
XCIII-XCIII of the elbow of FIG. 89;
[0150] FIG. 94 illustrates in detail a portion of the cross section
of FIG. 93;
[0151] FIG. 95 illustrates in detail a portion of the cross section
of FIG. 90;
[0152] FIG. 96 illustrates in detail a portion of the cross section
of FIG. 91;
[0153] FIG. 97 illustrates a lower rear perspective of the elbow of
FIG. 89;
[0154] FIG. 98 illustrates an upper front perspective of the elbow
of FIG. 89
[0155] FIG. 99 illustrates a front view of a further elbow;
[0156] FIG. 100 illustrates a cross section through the line C-C of
the elbow of FIG. 99;
[0157] FIG. 101 illustrates a cross section through the line CI-CI
of the elbow of FIG. 99;
[0158] FIG. 102 illustrates a cross section through the line
CII-CII of the elbow of FIG. 99;
[0159] FIG. 103 illustrates a cross section through the line
CIII-CIII of the elbow of FIG. 99;
[0160] FIG. 104 illustrates in detail a portion of the cross
section of FIG. 103;
[0161] FIG. 105 illustrates in detail a portion of the cross
section of FIG. 100;
[0162] FIG. 106 illustrates in detail a portion of the cross
section of FIG. 101;
[0163] FIG. 107 illustrates a lower rear perspective of the elbow
of FIG. 99;
[0164] FIG. 108 illustrates an upper front perspective of the elbow
of FIG. 99;
[0165] FIG. 109 illustrates a front view of another
shell/cushion;
[0166] FIG. 110 illustrates a cross section through the line CX-CX
of the shell/cushion of FIG. 109;
[0167] FIG. 111 illustrates a cross section through the line
CXI-CXI of the shell/cushion of FIG. 109;
[0168] FIG. 112 illustrates a right side elevation of the
shell/cushion of FIG. 109;
[0169] FIG. 113 illustrates a plan view of the shell/cushion of
FIG. 109;
[0170] FIG. 114 illustrates in detail a portion of the cross
section of FIG. 111;
[0171] FIG. 114A illustrates in detail a portion of the
shell/cushion in the nasal bridge region;
[0172] FIG. 115 illustrates in detail a portion of the cross
section of FIG. 110;
[0173] FIG. 116 illustrates an upper front perspective of the
shell/cushion of FIG. 109;
[0174] FIG. 117 illustrates a lower rear perspective of the
shell/cushion of FIG. 109;
[0175] FIG. 118 illustrates a front elevation of another retaining
ring for use with the shell/cushion of FIG. 109;
[0176] FIG. 119 illustrates a side view of the ring of FIG.
118;
[0177] FIG. 120 illustrates a diametrical cross section through the
ring of FIG. 118;
[0178] FIG. 121 illustrates a perspective view of the ring of FIG.
118;
[0179] FIG. 122 illustrates an exploded perspective view of the a
mask assembly comprising the components of the frame of FIG. 69,
the clip of FIG. 79, the elbow of FIG. 99 and the shell/cushion of
FIG. 109;
[0180] FIG. 123 illustrates the mask assembly of FIG. 122, with all
components shown in assembled condition, with some components being
shown in cross section;
[0181] FIG. 124 illustrates a detailed cross section through a
rivet, shell/cushion aperture and front frame aperture of FIG. 122,
which are located at the bottom of the mask assembly;
[0182] FIG. 125 illustrates a cross section through the retaining
ring of the mask assembly of FIGS. 122 and 123, with the left half
showing one arrangement and the right half showing another
arrangement to seal the shell/cushion and the elbow; and
[0183] FIG. 126 illustrates a s side view of a such as that
illustrated in FIGS. 69 to 78, wherein two rivet systems are formed
integrally therewith.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
.sctn. 1 Introduction
[0184] In various forms the embodiments provides a comfortable low
cost mask system which has few components and for example, has a
single walled cushion. In a preferred form it does not include a
forehead support, nor headgear clips, but it will be readily
understood that these can be included if desired.
[0185] The embodiments include a mask system which provides a
patient interface having a range of interchangeable sub-components
as part of a device for delivering a supply of air at positive
pressure to the airways of a patient in the treatment of sleep
disordered breathing. The mask system includes headgear and a mask
assembly (see FIG. 1).
[0186] Multiple versions of the mask system are described with
respect to the drawings:
[0187] Version 1: as depicted in FIGS. 1 and 7 being reusable with
components which disassemble for cleaning with a three point single
piece frame and having a shell/cushion with a continuous channel to
receive the frame;
[0188] Version 2: as depicted in FIGS. 2 to 6, 8 and 9, being
reusable with components which disassemble for cleaning with a
three point single piece frame and having a shell/cushion with four
discrete channels to receive the frame;
[0189] Version 3: depicted in FIG. 10 being a single use or
disposable unit with components which disassemble for cleaning with
a five point single piece frame;
[0190] Version 4; depicted in FIG. 11 being a reusable unit with
components which disassemble for cleaning with a five point single
piece frame;
[0191] Version 5: is not illustrated per se, but is a single use or
disposable unit with a three point two piece frame;
[0192] Version 6: is not illustrated per se, but is a reusable unit
with components which disassemble for cleaning with a three point
two piece frame;
[0193] Version 7: is a single or disposable unit, such as in
versions 3 or 5 with an elbow or connection piece as depicted in
FIGS. 99 to 108;
[0194] Version 8: is a reusable unit, such as in versions 1, 3, 5
with an elbow or connection piece as depicted in FIGS. 89 to 98;
and
[0195] Version 9: is not illustrated per se, but is a reusable or
single use unit of any of the previous eight versions, with a
shell/cushion as depicted in FIG. 68.
[0196] The embodiments also include four versions of elbows or
connection pieces for connecting a mask to a conduit, whereby the
connection piece completes the mask:
[0197] Version A: is a reusable disconnectable elbow as depicted in
FIGS. 30 to 37;
[0198] Version B: is a single use elbow which once assembled to a
mask cannot be disassembled therefrom and is as depicted in FIGS.
38 to 46;
[0199] Version C: is a reusable disconnectable elbow as depicted in
FIGS. 89 to 98; and
[0200] Version D: is a single use elbow which once assembled to a
mask cannot be disassembled therefrom and is as depicted in FIGS.
99 to 108.
[0201] The embodiments further include five versions of frames,
which connect to the shell/cushions and the headgear to position
the mask assemblies on a patient:
[0202] Version (i): a single piece three point frame receivable in
a channel in a shell/cushion as depicted in FIGS. 13 to 20;
[0203] Version (ii): a single piece five point frame receivable in
a channel in a shell/cushion as depicted in FIGS. 21 to 25;
[0204] Version (iii): a two piece three point frame as depicted in
FIGS. 69 to 88, which will sandwich a flange on a shell/cushion to
provide the shell/cushion with an exoskeletal support
structure.
[0205] Version (iv): which is not illustrated, but us a two piece
five point frame, which will sandwich a flange on a shell/cushion
to provide the shell/cushion with an exoskeletal support structure.
This version will be similar to Version (iii) as depicted in FIGS.
69 to 88; and
[0206] Version (v): which is not illustrated, where the frame is a
single piece and rivets to a flange on the shell/cushion.
[0207] The embodiments further include eight versions of
shell/cushions:
[0208] Version I: being as depicted in FIGS. 1, 7, and 56 to 66,
whereby the shell/cushion has a single continuous channel to
receive the frame, for re-use duty;
[0209] Version II: being as depicted in FIGS. 1, 7, and 56 to 66,
whereby the shell/cushion has a single continuous channel to
receive the frame, for single use duty;
[0210] Version III: being as depicted in FIGS. 2 to 6, and 47 to
55, whereby the shell/cushion has a plurality of discrete channels
to receive the frame, for re-use duty;
[0211] Version IV: being as depicted in FIGS. 2 to 6, and 47 to 55,
whereby the shell/cushion has a plurality of discrete channels to
receive the frame, for single use duty;
[0212] Version V: being as depicted in FIGS. 109 to 117, whereby a
flange is provided around the periphery and is for re-use duty;
[0213] Version VI: being as depicted in FIGS. 109 to 117, whereby a
flange is provided around the periphery and is for single use
duty;
[0214] Version VII: is not illustrated but is similar to the
shell/cushion of FIGS. 109 to 117, except that it has a plurality
of discrete flanges or housing around the apertures and is for
re-use duty; and
[0215] Version VIII: is not illustrated but is similar to the
shell/cushion of FIGS. 109 to 117, except that it has a plurality
of discrete flanges or housing around the apertures and is for
single use duty.
[0216] As illustrated in FIG. 1, the mask system 1, generally
comprises a mask assembly 10 having a shell/cushion 30, a frame 40,
a connecting piece or elbow 50 and a retaining ring 60 (which is
not visible in FIG. 1, but is visible in FIG. 7). As will be
readily understood, the combination of the versions of the basic
components as described above will yield a multitude of mask system
configurations.
.sctn. 2 Headgear
[0217] The headgear 20, as illustrated in FIGS. 1, 12 and 67 is
composed of three separate strap pieces 20.1, 20.2 and 20.3 which
are comprised of white non-latex elastic tape joined together to
form a three point headgear system. Headgear 20 is attached to the
frame 40 via the button holes 20.4 in the straps 20.1 and 20.2.
[0218] Table 1 shows exemplary dimensions of each of the straps
20.1, 20.2 and 20.3.
TABLE-US-00001 TABLE 1 Drawing ref Strap length (mm) Quantity 20.1
500-700 1 20.2 350-500 1 20.3 150-250 1
[0219] Button holes (3-5 mm) are placed in the middle along the
entire length of the straps with gaps between two button holes of
approximately 3.5-6.5 mm. The straps 20.1, 20.2 and 20.3 are each
20 mm wide and constructed from a knitted 70% polyester and 30%
non-latex elastomer which is white and biocompatible. The
elasticity of the preferred material is 49+-20 Newtons per metre
Nm.sup.-1. The above dimensions and materials are exemplary
only.
[0220] Ordinarily headgear can represent a significant cost in the
manufacture of a mask system. Thus, by manufacturing the headgear
20 from this particular low cost material can lead to a significant
cost saving for the headgear and the mask system as a whole.
[0221] The headgear 20 described above is preferably used for a
single use and then disposed of. However, to make the headgear in a
reusable form, the headgear can be moulded in a number of parts and
joined together with buttons or similar. Alternatively reusable
headgear can be moulded in one piece.
[0222] FIG. 67 shows a plan view of the headgear 20 while FIG. 12
shows the headgear 20 in use on a model head.
.sctn. 3 Shell/Cushion
[0223] Illustrated in FIGS. 1, 7, 11, and 56 to 66 is the
shell/cushion 30. The shell/cushion 30 defines a nose-receiving
cavity 30.1 and forms a seal with the face of the patient. The
shell/cushion 30 has a rearward aperture 30.2 through which the
patient's nose passes in use and a front aperture 30.3 to which a
connection piece or elbow 50 is attached. In a preferred form, the
shell/cushion 30 is single walled, however in other forms it may
have two or more walls, similar to the mask as taught in U.S. Pat.
No. 6,112,746 (incorporated herein by reference), known by the
trade mark MIRAGE.RTM.. The shell/cushion 30 has a sealing
structure 30.5 and a support structure 30.4 of a substantially
constant cross section. It can be moulded from any appropriate
material such as silicone or a thermoplastic elastomer.
[0224] The sealing structure 30.5 has a face contacting side 30.51
adapted to form a seal on a patient's face. The face contacting
side 30.51 includes a nasal bridge region 30.6, side regions 30.7
and a lip region 30.8. As can be seen from the figures the lip
region 30.8 has a series of four vent orifices 30.9 passing
therethrough. The face contacting side 30.51 is similar in shape to
the face contacting side of the mask known by the trade mark
PAPILLION (manufactured by MAP GmbH) or the mask known by the trade
mark MIRAGE (manufactured by ResMed Limited).
[0225] A range of shell/cushion 30 sizes can be provided to suit
different sizes of noses. For example, in one form, shell/cushions
can have a shallow nasal bridge region 30.6.
[0226] The shell/cushion 30 includes a frame-receiving channel 140
defined by a front flange 34 and a rear flange 36. The
shell/cushion 30 of FIGS. 7, 8 and 56 to 61 has the front flange 34
of a frame-receiving channel 140 as a continuous or unbroken
channel, which extends 100% of the way around the perimeter of the
shell/cushion 30.
[0227] As is visible in FIG. 56, the rear flange 36 is somewhat
wider in the lip region 30.8 and side regions 30.7. In these wider
portions on both the side regions 30.7 are elongated recesses 30.75
which provide an additional structure to engage and locate the
frame 40 or 140, as will be described below.
[0228] Illustrated in FIGS. 2 to 6, 8, 9, 10 and 47 to 55 is
another a shell/cushion 130. The shell/cushion 130 is similar to
the shell/cushion 30 and like parts have been like numbered. The
shell/cushion 130 differs from the shell/cushion 30 in that instead
of a continuous or unbroken channel 140 being provided all the way
around the shell/cushion, discrete channels 140.1, 140.2 and 140.3
are provided to cooperate with a fourth channel 140.4 (see FIG. 48)
to form four discrete points to receive four points on a frame 40
therein. Each channel discrete 140.1, 140.2,140.3 and 140.4 is
formed between a continuous rear flange 36, and an intermittent
front flange 34. The rear flange 36 surrounds the shell/cushion 130
all the way around the periphery thereof, so as to provide a flange
against which the frame 40 or 140 can push. The portion of the rear
flange 36 in the lower side regions 30.7 and lip region 30.8 are
thicker than in the nasal bridge region 30.6 so as to prevent a
"knife edge" forming in the nasal bridge region 30.6, but provide
structure to form the two lower apexes of the shell/cushion 30.
[0229] The shell/cushion 130 includes a series of vents or vent
orifices 30.9, which in a preferred form comprises four orifices.
The vent orifices 30.9 are formed through a thicker wall section
30.10 formed integrally on the shell/cushion 30. The wall section
30.10 is shown in FIG. 3. The wall section 30.10 has two functions.
The first is to form a front flange which with the rear flange 36
in the lip region 30.8 forms the lower channel 140.4. The second
function is that the wall section 30.10 allows the vent orifices
30.9 to be positioned at an angle with respect to the elbow.
However, the vent orifices 30.9 can be constructed at a flatter
angle, for example, 10.degree. to 15.degree. from the vertical
(with respect to the orientation shown in FIG. 3) so that when a
patient is wearing the mask system 1 and lying down, the vent
orifices 30.9 will be aligned generally at 10.degree. to 15.degree.
from the horizontal).
[0230] As illustrated in FIGS. 4, 8, 9, 48, 49, 56 and 57 the rear
flange 36 of the frame-receiving channel 140 has different
thickness in different regions. This feature is common to both
shell/cushions 30 and 130, but for convenience is described in the
proceeding passages with respect to shell/cushion 30 only. It is
thinner in the nasal bridge region 30.6 than in the lower side
regions 30.7 and the lip region 30.8. The rear flange 36 is between
1 to 3 mm thick, preferably 2 mm thick in the nasal bridge region
30.6, but can be of the order of 5 mm in the lower side regions
30.7 and lip region 30.8. This provides sufficient support for the
sealing structure 30.5 of the shell/cushion 30 in the nasal bridge
region 30.6 but doesn't lead to the creation of a "knife-edge"
which can be uncomfortable for a patient. A "knife edge" may form
if the sealing structure 30.5 of the shell/cushion 30 collapses,
and if a harder or thicker portion of the shell/cushion 30 was used
at the nasal bridge region 30.6. A "knife edge" is undesirable
because with prolonged use, it can create a pressure sore on a
patient's face. FIGS. 63 and 64 show sections from FIG. 62 with
thicker rear flange regions 36, whereas similar rear flange
sections 36 in FIGS. 65 and 66 are shown with thinner rear flange
regions.
[0231] Thus, as can be seen from the shell/cushion 30 and 130, the
shell/cushion can be provided with discrete channels or a
continuous channel. The channel or channels can, when their length
is totalled, be in the range of 75% to 100% of the perimeter of the
shell/cushion as in the case of shell/cushion 30 or in the range of
20% to 40% as in the case of shell/cushion 130 of the frame 40. An
advantage of the front flange extending 75% to 100% of the way
around the perimeter is that it is less likely to be removed by
inadvertence. From FIGS. 56 and 47 it can be seen that the
shell/cushions 30 and 130 have the wider portion of the rear flange
36 extending around the two lower apexes, so as to occupy
approximately 60% of periphery of the shell/cushion 30 and 130. To
achieve the desired structural function and flexibility in the
nasal bridge region, this wider flange could occupy approximately
40% to 80% of the periphery of the shell/cushions 30 and 130
centered around the lower regions thereof.
[0232] FIG. 52 shows in cross-section a portion 30.31 of the
shell/cushion 130. The portions 30.31 are those portions linked to
the front aperture 30.3, which will receive the retaining ring 60.
The region 30.31 has a channel 524 into which the rear flange of
the retaining ring 60 will be received. The patient end of the
aperture has an annular flap 526 which is relatively thin and
flexible, and which reduces the inside diameter of the aperture
30.3. The purpose of the flap 526 is to provide a seal with a
portion of the connection piece or elbow 50, as will be described
below in chapter .sctn. 7 Assembly of the components below.
[0233] The section 522 as illustrated in FIG. 52 is a relatively
thin walled section. Such a thin walled section is particularly
useful for the manufacture of a disposable mask. The thin walled
section 522 can thus be designed to tear if a person attempts to
remove the connection piece or elbow 50, for example to wash the
elbow 50. This aspect represents a safety feature preventing re-use
of a disposable mask having a shell/cushion 130, reducing the
likelihood of cross-infection.
[0234] Alternatively, if the shell/cushion 130 were to be reusable
then the section 522 will be provided with a thicker dimension
which would prevent the section 522 tearing at the time of
disassembly. The shell/cushion 30, being of a reusable nature, will
have a cross section similar to that of FIG. 52 with the section
522 being of a thicker dimension than that for shell/cushion
130.
[0235] Illustrated in FIG. 68 is a diagrammatic representation of a
modified shell/cushion 230. In this shell/cushion 230 a small
bellows portion 230.1 is provided (or a alternatively a flexible
neck can be provided) adjacent the aperture 30.3 where a connection
piece or elbow 50 fits into the shell/cushion 230. This bellows
portion 230.1 provides a flexible element which allows movement
between the connection piece or elbow 50 and the shell/cushion 230.
By providing this flexibility there is a decoupling of any torque
which may attempt to transfer between the elbow and the
shell/cushion.
[0236] Illustrated in FIGS. 109 to 117, 122 and 123 is another
shell/cushion 330, which is similar to the shell/cushions 30 and
130 described above with like parts being like numbered. The
shell/cushion 330 differs from the shell/cushions 30 and 130 in
that instead of a channel 140, or a series of discrete channels
140.1, 140.2, 140.3 and 140.4 being provided around the periphery
to receive a frame 40, a continuous peripheral flap or flange
330.1. The flange 330.1 has the same shape as a two piece frame
(see description below with respect to FIGS. 69 to 88) which will
sandwich the flange 330.1.
[0237] The flange 330.1 includes seven apertures 330.2 and 330.3
therethrough. The four apertures 330.2 are of an approximate
diameter of 5.75 mm while the three apertures 330.3 are of an
approximate diameter of 3 mm. The apertures 330.2 and 330.3 receive
therethrough rivets formed on one piece of the two piece frame as
will be described below. As the rivets which pass through the
apertures 330.2 have a barbed head which is of a larger diameter
than the shank the apertures 330.2 are of a larger diameter to
accommodate this large diameter barb.
[0238] While FIGS. 109 to 117 display a continuous flange 330.1
around the periphery of the shell/cushion 330, a satisfactory
result is also expected should a series of seven discrete flanges
or housing were to be provided around the apertures 330.2 and
330.3. Whilst this will give the frame which sandwiches these
flanges some seven points of grip or contact with shell/cushion,
these seven points are expected to be sufficient to maintain the
shape of the shell/cushion when it is in use.
[0239] As can be seen from FIG. 114 the exterior of the
shell/cushion 330, which provides a seal with a patients face, has
a shot blasted surface finish. Such a shot blasted finish will
provide a more comfortable feel for the patient. The cross section
of FIG. 114 is taken through the middle region of the shell/cushion
330. It can be seen in FIG. 114, that in the region designated by
the wall 330.11, behind the flange 330.1, the thickness of the wall
330.11 is kept relatively thick and then tapers in a rearward
direction. In contrast to this, as is illustrated in FIG. 114A, in
the nasal bridge region 30.6, the cross section is different,
whereby the wall 330.11 (shown for comparison in phantom line) is
thinned to form the wall 330.12 which is a relatively thinner and
substantially constant cross section wall portion. This reduction
in wall thickness in the nasal bridge region 30.6 helps to reduce
the chances of a "knife edge" being formed in use on a patient, in
the nasal bridge region 30.6.
[0240] Illustrated in FIGS. 109, 110, 112, and 113 the
shell/cushion 330 is illustrated as having a manufacturing tab or
de-moulding tab 330.13. The de-moulding tab 330.13 allows a robotic
de-moulder to grab the shell/cushion 330 safely and securely,
without having to grab any other parts of the shell/cushion 330.
This can limit the possibility of damaging any of the other parts
of the shell/cushion 330 in the process of cutting off any excess
material by a robot which may have resulted from the moulding
process.
[0241] The shell/cushion 330 is specifically for one time hospital
use. As can be seen form FIG. 115, the shell/cushion 330 has a thin
walled section, approximately 0.33 to 0.75 mm in thickness. As
described above this will provide a line of weakness allowing the
shell/cushion to tear, should it be attempted to remove the
retaining ring 60 from the recess 524. The propensity to tear
limits the ability to clean the shell/cushion 330 before re-use,
thus preventing re-use.
[0242] To provide some additional rigidity whilst at the same time
keeping the material used to a optimum level, there is provided on
the shell/cushion 330 a series of four radially extending
reinforcing ribs 330.4 which extend away from a generally circular
reinforcing ring 330.6 which surrounds the region 30.31 and
aperture 30.3. The ribs 330.4 and 330.6 are formed integrally in
the shell/cushion 330, but are of a greater thickness of material
than the regions 330.5. The ribs 330.4 and 330.6 are approximately
2 to 3 mm in thickness while the regions 330.5 are approximately 1
to 1.5 mm in thickness. This arrangement helps to provide better
aesthetic quality while also providing greater structural support
where required, but a softer feel at the seal locations.
.sctn. 4 Frame
[0243] As is illustrated in FIGS. 1 to 9, and 12 to 18, the frame
40 is shaped and adapted to be mounted on the shell/cushion 30 and
130, and provides anchor points 132 having apertures 40.1, 40.2 and
40.3 for headgear 20. The frame 40 provides three anchor points 132
and is shown in detail in FIGS. 13 to 20.
[0244] The frame 40 is of a generally triangular shape with rounded
apexes, and has a base approximately 90 mm wide and a height of
approximately 84 mm. Other exemplary dimensions are as indicated in
the FIGS. 13 to 20.
[0245] The frame 40 can be made to any suitable configuration of
anchor points 132 so as to provide a variety of fittings to suit
the particular needs of individual uses. In this regard, the
placement of anchor points 132 can be changed in a manner described
in the published PCT patent application WO 02/45784, the contents
of which are hereby incorporated by cross reference. In this way
the adaptability of the mask system 1 is enhanced as the mask frame
40 is relatively inexpensive to manufacture.
[0246] Each anchor point 132 is formed from a frame member 132.2
which surrounds an aperture 40.1, 40.2 or 40.3. The apertures 40.1,
40.2 and 40.3 allows the ends of the straps 20.1 and 20.2 to be
threaded therethrough.
[0247] On a middle portion of the frame member 132.2 is a mushroom
headed spigot 132.1, which can be threaded though one of the button
holes 20.4 on the respective ends of the straps 20.1 and 20.2. In
alternative embodiments the spigot may be replaced by other methods
of retention such as hooks.
[0248] If desired the user need not thread through the apertures
40.1, 40.2 or 40.3, and instead attach directly onto the mushroom
headed spigots 132.1, however, there is less likelihood of
inadvertent disconnection when in use if the ends of straps 20.1
and 20.2 are threaded through the respective apertures 40.1, 40.2
or 40.3 as all movement of the ends of the straps 20.1 and 20.2
will not tend to try to pull the button holes 20.4 over the
mushroom headed spigots 132.1.
[0249] FIG. 18 shows a detailed view of the mushroom headed spigot
132.1 of an anchor point 132 in cross-section from FIG. 14. In use,
a patient selects the appropriate button hole 20.4 of the headgear
20 and then passes it through the apertures 40.1, 40.2 or 40.3 and
over a mushroom headed spigot 132.1 on the frame 40 to set the
headgear straps at the appropriate length.
[0250] The frame 40 has rearwardly projecting ribs 40.7, in the
vicinity of the two lower anchor point 132, near to the base of the
frame 40. The ribs 40.7 are sized and shaped so as to be received
into the elongated recesses 30.75 on the shell/cushions 30 and
130.
[0251] The frame 40 provides an indent 40.4 which also extends away
from the face of the patient as is illustrated in FIGS. 14 and 15.
This indent 40.4 helps to provide space for the nasal bridge
section of the shell/cushion 30 or 130, without exerting a pressure
point onto the patient's nasal bridge.
[0252] As is illustrated in FIGS. 10, 11 and 21 to 25 is another
frame 140 which is similar to the frame 40 of FIGS. 14 and 15 and
like parts have been like numbered. The difference between the
frame 40 and the frame 140 is that the frame 140 provides up to
five anchor points 132.
[0253] The upper anchor point 132 includes a three sided frame
member 132.2, and on each side of the frame member 132.2 is
located, at a generally central location a mushroom headed spigot
132.1.
[0254] The frame 140 can thus be used with the headgear 20
described above which provides three ends of straps 20.1 and 20.2,
or it can be used with a modified form of headgear(not illustrated)
with five straps.
[0255] As an alternative (not illustrated), the frame 140 may also
provide four anchor points 132 and be used with a modified form of
headgear (not illustrated) with four straps.
[0256] Preferably each of three straps that can be used with the
upper anchor point 132 will be threaded through the aperture 40.2,
whereby the straight sided nature of the three sides will interact
with a respective mushroom headed spigot 132.1 to firmly secure the
ends of the straps thereto.
[0257] Illustrated in FIGS. 69 to 78 is a first piece 240 of a
frame for use with the shell/cushion 330 of FIGS. 109 to 117, and
122 and 123. The piece 240 is the outward facing portion of the
frame once assembled.
[0258] Illustrated FIGS. 79 to 88 is a second piece 340 of the
frame for use with the shell/cushion 330 of FIGS. 109 to 117, 122
and 123. The piece 340 is the inward facing potion of the frame
once assembled.
[0259] The pieces 240 and 340 are of similar overall shape to the
frames 40 and 140, and like parts are like numbered.
[0260] The piece 240 receives and secures the piece 340 therein, by
means of four large diameter apertures 240.1, which as can be seen
most clearly from FIGS. 72 and 76 have a tapered entry way 240.2
formed in a rearwardly extending cylindrical wall 240.21. In
alternative embodiments, there may be between one and five large
diameter apertures 240.1. The tapered entry way 240.1 leads to a
constricted aperture 240.4 and a larger diameter recess 240.3 on
the other side of constructed aperture to the entry way 240.2. The
larger diameter recess 240.3 has at its base a shoulder 240.5.
[0261] The apertures 240.1 receive rivets 340.1 on the piece 340.
As can be seen from FIGS. 82, 83, 85 and 86 and the rivets 340.1
have a tapered shank 340.2 and a tapered mushroom head 340.3, the
underside of which has a shoulder 340.6. Surrounding the base of
the shank 340.2 is a housing 340.4 which has an annular recess
340.5 between the base of the shank 340.2 and the housing 340.4.
The tapered end of the mushroom head 340.3 allows the head 340.3 to
push through the entry way 240.2 and the aperture 240.4, and once
through, shoulders 340.6 and 240.3 will be adjacent each other
preventing the withdrawal of the rivet 340.1 from the aperture
240.1.
[0262] The piece 240 includes three blind holes 240.6 into which
will be received respective straight sided spigots 340.7. In
alternative embodiments there may be differing numbers of blind
holes and respective straight sided spigots, for example a number
of blind holes and respective spigots between one and seven.
[0263] Illustrated in FIG. 126 is a frame 440 which is similar to
the frame piece 240 of FIGS. 69 to 78. Accordingly, like parts have
been like numbered. The frame 440 differs from the frame 240 in
that the frame 440 does not require a second frame member to be
used therewith. Instead the frame 440 has a rivet 440.1 located
adjacent each aperture 240.1. The rivets 440.1, of which only one
is illustrated for convenience, has a lanyard 440.3 which ties the
rivet 440.1 to the frame 440. A bearing surface 440.4 is provided
from which extend the rivet shaft 440.5 which terminates in a
mushroom head 440.6. The rivet 440.1, including the lanyard 440.3
can be integrally moulded with the frame 440, and provides an easy
means of assembly.
[0264] To assemble the rivet 440.1, the frame 440 is placed
adjacent the flange 330.1 of the shell/cushion 330, then the rivet
440.1 is moved into position against the rear face of the flange
330.1 and pushed home so that the bearing surface 440.4 can
sandwich or compress the flange 330.1 to the rear face of the frame
440.
[0265] For the sake of illustration the aperture 240.1 near the
bottom of the frame 440 has a different rivet structure associated
with it. The rivet 440.2 has relatively thin panel 440.7 which
extend away from the frame 440. A second panel 440.8 is hinged by a
hinge 440.9 to the panel 440.7. Extending away from the panel 440.8
is a rivet shaft 440.5 which terminates in a mushroom head 440.6,
in much the same way as the rivet 440.1.
[0266] The distance between the hinge 440.9 and the frame 440 (the
height of the panel 440.7) can be sized to provide either a loose
or snug fit around the flange 330.1, or if desired sized to provide
as much compression of the flange 330.1 as possible. By positioning
the flange 330.1 adjacent the aperture 240.1 and folding the panel
440.8 over so that the head 440.6 of the rivet is pushed home into
the aperture 240.1, the rivet 440.2 will hold the flange 330.1 in
place relative to the frame 440.
[0267] The frame 40, the pieces 240 and 340, and the frame 440 can
be moulded from any appropriate material such as polycarbonate.
.sctn. 5 Connection Piece or Elbow
[0268] As is illustrated in FIGS. 1, 7, 9, 11, 12, 62 to 66, and
most particularly in FIGS. 30 to 37, the elbow 50 has a distal end
52 which is adapted to engage, whether with or without a swivel or
union 250.2 (see FIG. 1) with an air delivery conduit (not shown).
The union 250.2 is illustrated in FIG. 1, but is optional. The
manner by which the union 250.2 connects to the elbow 50, is that
the internal cylindrical surface of the distal end 52 includes an
annular groove 250.1 (see FIGS. 11, 32, 35A and 35B), which will
receive an annular lip 250.3 on the swivel 250.2.
[0269] A proximal end 50.1 of the elbow 50 is adapted to engage
with both a shell/cushion 30, 130, 230, 330 and a retaining ring 60
positioned within the aperture 30.3 of the shell/cushion. Two,
circumferentially equi-spaced or diametrically opposed, tongues
50.3 extend away from the body of the elbow 50 near to the proximal
end 50.1. Each tongue 50.3 has an arcuate undercut 50.2 which is
located on an inwardly facing surface 50.4 of the tongue 50.3. The
undercuts 50.2 engage with the retaining ring 60. Each finger 50.3
is located at diametrically opposite locations on the elbow 50, and
are located on either side of the elbow 50 at the proximal end 50.1
thereof.
[0270] At the ends of the tongues 50.3 there are included finger
grips 54. The finger grips 54 enable a user to pull the tongues
50.3 in a radially outward direction relative to the proximal end
50.1, thereby permitting the undercuts 50.2 to clear the rim of
retaining ring 60. This then allows the elbow 50 to be disassembled
from the mask assembly 10, whereby it can be removed for cleaning.
Located near to the finger grips are two undercuts to removably
engage with the retaining ring.
[0271] The inside surfaces of the finger grips 54 include a tapered
entry way 50.7, whereby when the proximal end 50.1 is pushed into
contact with a rim of the retaining ring, the finger grips 54, and
thus the undercuts 50.2 are pushed away from the rim of the
retaining ring 60, thereby allowing the undercuts to push past the
rim, and biased radially inwardly back into engagement, preventing
the separation of the proximal end 50.1 from the retaining ring
60.
[0272] An exemplary shape and dimensions of the elbow 50 are
indicated in the FIGS. 30 to 37.
[0273] Illustrated in FIGS. 10, and FIGS. 38 to 46 is another elbow
150. The elbow 150 is similar to the elbow 50 described above and
like parts have been like numbered. However, the elbow 150 differs
from the elbow 50 in that the elbow 150 does not include the
moveable tongues 50.3 and finger grips 54 which are included on the
elbow 50. Instead, the elbow 50 has six discreet undercuts 50.2
equi-spaced the inner edge 50.5 on the skirt 50.6 which surrounds
the proximal end 50.1. In this way the elbow 150 is adapted to be
not removable from the shell/cushion 30, 130, 230, 330 and is thus
useful for a disposable mask.
[0274] The undercuts 50.2 are formed adjacent the apertures 50.11
through the skirt 50.6. The apertures 50.11 are formed by that
portion of the mould which forms the undercut 50.2, preventing
molten plastic occupying that space. If desired more or less
discrete undercuts 50.2 can be provided.
[0275] The inside surfaces of the skirt 50.6 include a tapered
entry way 50.7, whereby when the proximal end 50.1 is pushed into
contact with a rim of a retaining ring 60, the skirt 50.6, and thus
the undercuts 50.2 are pushed away from the rim of the retaining
ring 60, thereby allowing the undercuts 50.2 to push past the rim.
The construction of the skirt 50.6 provides a radially inward bias
forcing the undercut 50.2 back into engagement once past the rim,
thereby preventing the separation of the proximal end 50.1 from the
retaining ring 60.
[0276] The elbow can be moulded from any appropriate material such
as polycarbonate or polypropylene.
[0277] The elbows 50 and 150 each include a port 56, such as Luer
port, to enable access to the interior of the mask shell/cushion.
For example, a pressure sensor may be attached. A polypropylene or
silicone cap can be used to cover and seal the port when not in
use.
[0278] The elbows 50 and 150 can be sized so as to freely rotated
when mounted on the mask assembly 10. However, it is preferable
that they are not able to freely rotate. Thus while rotation is
allowed, when mounted onto a mask assembly 10, the inter-engagement
of the components provides as a braking system. This means that,
while adjustable, it tends to remain in the position in which it
has been set. This is achieved through the combination of sizes
shown and the use of one material on the elbow 50 and a different
material on the shell/cushion with which it engages. This can be
achieved through a slightly interfering fit between the ends of the
undercuts 50.2 on the elbow 50 and shell/cushion 30, 130, 230,
330.
[0279] Preferably a suitable combination of materials and component
configurations are selected so as to allow the user by hand to
easily rotate the elbow to any desired position and once
positioned, the elbow 50 or 150 will not move when experiencing the
forces which are applied when the mask is attached to the gas
conduit and it is in use by a sleeping patient. This allows the
user to position the elbow 50 or 150 and thereby the gas conduit
relative to the mask and face according to personal preference.
[0280] The elbows 50 and 150 and frame 40 are not directly
connected, since their contact is through the shell/cushion 30,
130, 230, 330. Since the shell/cushion is constructed from a
flexible material, movement of an air delivery conduit attached to
the swivel elbow does not directly disrupt the seal of the
shell/cushion. In this way, decoupling of drag forces from the air
delivery conduit can be achieved.
[0281] Illustrated in FIGS. 89 to 98 is a connection piece or elbow
250 which is similar to the elbow 50 and like parts have been like
numbered. The elbow 250 differs from the elbow 50 by two prominent
features. The first is that the elbow 50 joined direct to a conduit
to supply air via the distal end 52. Whereas the elbow 250 provides
a groove 250.1 in its distal end 52, so as to receive in the dital
end a 180.degree. union 250.2 (see the union 250.2 of FIG. 122),
which will be rotatably joined, by the annular lip 250.3 on the
union 250.2 being received in the annular groove 250.1. This will
provide a swivel connection between the conduit which will supply
air, and the elbow 250.
[0282] The second feature of difference is that the elbow 250, as
best seen in the cross section of FIG. 91, has vent wall 250.4
which extends away from the passage wall 250.5 which directs air
flow out of the elbow 250.
[0283] In the vent wall 250.4 is a series of four vent orifices
250.6, which are seen in more detail in cross section of FIG. 95.
The orifices 250.6 lie at an angle to the outlet direction of air
flowing out of the elbow 250. This angle is approximately
35.degree., or the complementary angle is 55.degree. as is
indicated in FIG. 90.
[0284] Extending away from the vent wall 250.4 is a divergent
housing 250.7. By being divergent, any exhaled gases passing
through the vent orifices 250.6 will be readily dispersed.
[0285] Illustrated in FIGS. 99 to 108, and 122 and 123, is a
connection piece or elbow 350, which is similar to the elbow 150
and like parts have been like numbered. The elbow 350 also has the
same first and second features or differences described above with
respect to the elbows 50 and 250, and accordingly like parts have
therewith have also been like numbered.
[0286] The elbow 350, being used to produce a mask assembly
predominantly for single use and hospital use, includes a side
located and directed Luer port 56. The side mounted Luer port 56 is
particularly helpful for the situation where a tube is connected
for monitoring purposes. This tube, by being mounted onto the Luer
port 56 of the elbow 350, which if it is free to swivel, will mean
that there need be no relative twisting of the monitoring tube
relative to the supply conduit. This could not happen if the Luer
port 56 were on the shell/cushion.
[0287] While the connection pieces or elbows 250 and 350 only have
a 90.degree. angle between the inlet at the distal end 52 and the
outlet at the proximal end 50.1, it will be readily understood that
the connection piece can be constructed with the vent wall 250.4,
vent orifices 250.6, and divergent housing 250.7 with any
appropriate angle between the inlet at the distal end 52 and the
outlet at the proximal end 50.1. This angle can be 180.degree.,
whereby an in-line or union connection piece can be produced.
.sctn. 6 Retaining Ring
[0288] A retaining ring 60 for use with the mask assembly 10 is
show in FIGS. 7, 8, 9, 11, and in more detail in FIGS. 26 to 29.
The ring 60 can be manufactured from any appropriate material such
as polycarbonate.
[0289] The ring 60 has an outer diameter of approximately 33 mm and
a thickness of 9 mm. Other exemplary dimensions are shown in FIG.
27. FIGS. 8 and 9 show how the retaining ring is positioned in the
mask assembly in use.
[0290] Illustrated in the cross sectional views of FIGS. 8 and 9
and in FIGS. 26 to 29 it can be seen that the retaining ring 60
comprises a cylinder 62, an annular front flange 64 and a rear
flange 66, which between them form an annular groove 67. The rear
flange 66 is adapted to be inserted and retained within a
complementary shaped channel 524 adjacent the front aperture 30.3
of a shell/cushion 30, 130, 230, 330.
[0291] The front flange 64 provides a square rear surface 65 which
forms the front wall of the groove 67. Further the rim 68 of the
front flange 64 is bevelled or tapered so that when it enters the
tapered entry way on the elbow 50, it will force the undercuts 50.2
to pass thereover.
[0292] It will be noted that the rear flange 66 is symmetrical in
shape, while the front flange 64 is not. Further the rear flange 66
is set back from the rear end of the cylinder 62, whereby a
cylindrical portion 69 protrudes axially rearwardly away from the
rear face of the rear flange 66.
[0293] Illustrated in FIGS. 118 to 123 is another form of the
retaining ring 160 which is similar to the ring 60, and like parts
have been like numbered. The ring 160 differs from the ring 60 in
that it has a symmetrical configuration so that it can be inserted
in either orientation. The front and rear flanges, both marked with
numeral 64 are a mirror image of each other and are shaped
similarly to the front flange 64 of the ring 60. That is both
include a rim 68 which is bevelled or tapered. It will be noted
that the ring 160 does not include a rearwardly axially extending
cylindrical portion such as is present on the ring 60 as feature
69.
[0294] As can be seen from the cross section of FIG. 120, the
aperture through the ring 160 has convergent-divergent walls 160.1
and 160.2. These walls are angled or tapered at an angle of
20.degree. so as to assist in the moulding of the ring 160, and to
prevent jamming of the proximal end 50.1 of elbows 50 and 250 when
these elbows are disconnected from the ring 160.
[0295] The shape of the groove 524 on the shell/cushion to receive
the flange 64 of ring 160 is preferably of a complementary shape to
allow the ring 160 to provide support.
.sctn. 7 Assembly of the Components
[0296] Assembly of Version 1 of a mask system described in chapter
.sctn. 1 above, will now be described with reference to FIGS. 7, 8
and 9.
[0297] A frame 40 is pushed into position on the shell/cushion 30
from the front of the shell/cushion 30 and is inserted and engages
with the channel 140 on the shell/cushion 30. The retaining ring 60
is adapted to engage with a channel 250 on the shell/cushion 30.
The process is similar for the first embodiment.
[0298] Illustrated in the cross sectional views of FIGS. 8 and 9 of
the mask assembly 10, the connection between the elbow 50,
retaining ring 60 and shell/cushion 30 is visible. The rear flange
66 of the retaining ring 60 is adapted to be inserted and retained
within in the channel 524 adjacent the front aperture 30.3 of a
shell/cushion 30.
[0299] The undercut 50.2 on the elbow 50 is adapted to engage with
the rear surface 65 of the front flange 64, thus retaining the
elbow 50.
[0300] When the proximal end 50.1 passes though the retaining ring
60, seal is formed between a flange or flap 526 on the
shell/cushion 30 and the proximal end 32 of the elbow 50. In this
way, a leak proof seal, which allows rotation of the elbow 50
relative to the shell/cushion 30 is formed, since the flange or
flap 526 extends over the proximal end of the elbow in an annular
fashion. This results in a conformable seal between the
shell/cushion and elbow.
[0301] Assembly of Version 7 of a mask system described in the
.sctn. 1 Introduction above, will now be described with reference
to FIGS. 122 to 125.
[0302] Assembly of Version 7 is very similar to that of version 1
described above, except that instead of a single piece frame 40 a
two piece frame, made up of pieces 240 and 340 is used, and instead
of a shell/cushion 30 with a channel 140 being used a shell/cushion
330 with a peripheral flange 330.1 is used. The assembly of: (a)
the frame to the shell/cushion; and (b) the retaining ring and
elbow to the shell/cushion; can be done in any order.
[0303] To assemble the frame, a manufacturer will align the rivets
340.1 and spigots 340.7 with the respective holes 330.3 and 330.2,
and pass the rivets and spigots through these holes in a rearward
to forward direction, starting at the rear of the shell/cushion
330. Once the rivets have been received through the holes 330.2 and
the rest of the flange 330.1 is sitting adjacent to front facing
surfaces of eh piece 340, then the piece 240 is aligned so that the
apertures 240.1 align with the rivets 340.1, whereby exerting a
compressive force on the two pieces 240 and 340 will force the
tapered mushroom heads of the rivets 340.1 to pass through the
constricted aperture of the apertures 240.1. By appropriately
sizing the rivets 340.1 and the apertures 240.1, it may be
necessary to compress the flange 330.1 whereby the pieces 240 and
340 will keep the flange 330.1 compressed therebetween once the
mushroom head of the rivets are locked into the apertures 240.1.
Alternatively, as illustrated in FIG. 124, the gap between the
pieces 240 and 340 can be sized to receive the flange 330.1 without
any compression thereof.
[0304] When the rivets 340.1 are locked into the apertures 240.1,
the spigots 340.7 pass through the holes 330.3. The three spigots
340.7 prevent the flange 330.1 from extricating itself from the
sandwich formed by the clamping of pieces 240 and 340.
[0305] The assembly of the retaining ring 160 and the elbow 350
onto the aperture 30.3 of the shell/cushion 330 is the same
procedure as described above in respect of version 1. As
illustrated in FIG. 125, the flange 526 can, once the elbow 350 is
assembled to the retaining ring 160 and shell/cushions 330, overlie
(as illustrated on the right half of FIG. 125) the rim 32.1 of the
proximal end 32 of elbow 350, or as illustrated on the left half of
FIG. 125, the flange 526 can circumferentially seal on the
cylindrical outer surface 32.2 adjacent the rims 32.1.
[0306] Described above is a feature of single use mask assemblies
where the shell/cushion 30, 130, 230, 330 has a reduced thickness
portion to provide a tear point. A single use version is able to be
manufactured without such a line of weakness or tear point. Such a
single use version, when a single use elbow is used, such as elbows
150 or 350 described above, will allow the shell/cushion 30, 130,
230, 330 (without any reduced thicknesses or tearing points) to
separate from the assembled retaining ring 60 or 160 and the elbow
150, or 350, while the elbow 150 or 350 retains the retaining ring
60 or 160 captured thereon. In this way, such a mask assembly will
not be able to be reassembled due to the inability to extract or
disconnect the retaining ring 60 or 160 from the elbow 150 or
350.
[0307] Although the invention has been described with reference to
preferred embodiments, it is to be understood that these
embodiments are merely illustrative of the application of the
principles of the invention. Numerous modifications may be made
therein and other arrangements may be devised without departing
from the spirit and scope of the invention.
[0308] It will be understood that the invention disclosed and
defined herein extends to all alternative combinations of two or
more of the individual features mentioned or evident from the text.
All of these different combinations constitute various alternative
aspects of the invention.
* * * * *