US20220296839A1 - Respiratory mask - Google Patents

Abstract

A respiratory mask, a mould for a respiratory mask, as well as to a method for producing a respiratory mask are disclosed, in which manufacturability and usability of respiratory masks are improved. A respiratory mask is disclosed for administering a breathable gas to a patient, the respiratory mask comprising a first component formed from a flexible material and a second component formed from a material that is more rigid than the flexible material, wherein the first component is formed onto the second component by an overmoulding process.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS
• This application is a continuation of U.S. application Ser. No. 17/075,310, filed Oct. 20, 2020, which is a continuation of U.S. application Ser. No. 14/093,603, filed Dec. 2, 2013, now U.S. Pat. No. 10,864,341, which is a continuation of U.S. application Ser. No. 11/988,569, filed Jan. 10, 2008, now U.S. Pat. No. 8,596,273, which is the U.S. national phase of International Application No. PCT/AU2006/001021, filed Jul. 19, 2006, which designated the U.S. and claims priority to German Application Nos. 10 2005 033650.7, filed Jul. 19, 2005, and 10 2005 033648.5, filed Jul. 19, 2005, the entire contents of each of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION1.0 Technical Field
• The invention relates to respiratory masks and manufacturing processes for respiratory masks. In particular, the invention relates to overmoulding portions of respiratory masks.
• It should be noted that the phrase “respiratory mask” in this specification includes any type of patient interface, including full face masks, nasal masks, and nasal prong masks etc.
2.0 Introduction to Respiratory Masks
• Respiratory masks are used for administering a breathable gas, such as ambient air, at a pressure that is, at least sometimes, above the ambient pressure. This is known as Positive Airway Pressure (PAP) therapy, such as Continuous Positive Airway Pressure (CPAP) or Variable Positive Airway Pressure (VPAP) therapy, and may be used for treating Sleep Disordered Breathing (SDB) or other medical conditions.
• International Patent Application PCT/EP02/11798, filed by Medizintechnik fur Arzt and Patient (MAP), now ResMed R&D Germany GmbH, discloses a respiratory mask for administering a breathable gas to a user. This respiratory mask makes it possible, when worn by a user, to seal off an interior volume of the respiratory mask from the environment. Such respiratory masks are used particularly in conjunction with medical or therapeutic administration of breathable gases (and additions thereto, such as drug vapours), as well as in the industrial field, for instance in the field of gas masks and breathing equipment. Typically, the interior volume is sealed using a sealing cushion or lip structure that is inwardly curved and extends around an opening in the mask and seals against the user's face. Sealing cushions are generally made from an elastically deformable material, such as silicone and seal by compression against the user's face. The level of sealing achieved generally increases with the contact pressure of the sealing cushion against the face.
2.1 Manual Labour
• It is known amongst skilled persons that conventional mask systems are difficult to assemble. Consequently, assembly of components requires significant labour time, particularly while assemblers are learning. Further labour is required to check the correct assembly of mask components. Manual labour increases the cost of goods and subsequently may decrease the profitability of respiratory mask manufacturers and/or make masks more expensive for patients.
• Automation of the manufacturing assembly process by using robotics, for example, is difficult due to the often complex manipulations required to assemble mask components. It is also known that flexible components, as are common in masks and mask systems, are exceedingly difficult to handle robotically. For automation to be achieved a very high level of robotic dexterity would be required and the expense of designing, manufacturing and configuring such robotics has generally been considered prohibitive.
2.2 Moulding
• In general terms, the greater the number of components a mask includes, the more expensive it is to manufacture because more component moulds are required.
2.3 Assembly by Patients
• Assembly and disassembly of mask components by patients can be difficult (e.g. after washing the mask prior to use). This problem is often exacerbated by the often relatively low dexterity of patient's suffering from sleep disordered breathing (e.g. because of age, weight or arthritis). Generally, therefore, the more components a mask has, the more difficult it is for patients to assemble. Furthermore, the higher the number of mask components, the greater the risk of those components getting lost and the greater the risk of mis-assembly.
2.4 Biological Contamination
• Another problem with masks assembled from components that can be separated by a user is the build-up of biological contaminants in the crevices between the components, even when the mask is being regularly washed.
2.5 Mask Comfort
• One ongoing problem encountered in mask design is the difficulty associated with creating a comfortable mask. Ordinary silicone membrane sealing technology can feel unpleasant and sometimes lead to pressure sores when the mask in tightened too much for an extended period of time.
2.6 Mask Aesthetics
• It is known that good mask aesthetics can be achieved by a sleek, simple design that does not have a ‘busy’ appearance. However, the various functional requirements of masks sometimes impinges on a designers ability to design a mask with good aesthetics. This problem can be compounded when masks are made from a relatively large number of components that do not connect in a smooth, contoured fashion.
BRIEF SUMMARY OF THE INVENTION3.0 Embodiments of The Present Invention
• Embodiments of the present invention seek to address one or more of the abovementioned problems or to at least provide a commercially valuable alternative.
• One aspect of the invention relates to a method for manufacturing a respiratory mask wherein at least one step in the manufacturing process is the integral forming of at least two components in or from at least two different materials. Another aspect of the invention relates to a respiratory mask manufactured by the above method.
• Preferably, the integral forming is an overmoulding operation which is automated, for example, by using robotics. Overmoulding may be performed by any known moulding technique, including surface treatment by any known treatment, such as plasma treatment. An overmoulding step may be used to mould a flexible component onto a component that is less flexible than the flexible material (henceforth a “substantially rigid component”). In one embodiment, the mask cushion (e.g., silicone) and frame (e.g., polycarbonate) are co-moulded using one of the manufacturing processes described herein.
• As a result, it advantageously becomes possible to create a respiratory mask in which relatively complex geometries of the flexible components and of the substantially rigid components coupled to them can be realized. Furthermore, the relatively time-consuming and labour intensive mask manufacturing process can now be either partially or completely automated. This advantage arises because one or more mask assembly steps and mask components may not be required because two components (e.g. cushion and frame) are joined during moulding and so do not require subsequent assembly.
• In an especially preferred embodiment of the invention, the integral forming of a flexible component onto a substantially rigid component is done directly in an injection moulding tool. This injection moulding tool preferably includes multiple cavities.
• A liquid silicone rubber (LSR) material is preferably used for the flexible material and a polycarbonate plastic is preferably used for the substantially rigid material. In an especially preferred embodiment of the invention, the integral forming of the components is carried out in such a way that the flexible component can be manually separated from the substantially rigid component. This allows the flexible component to be removed as required. It is also possible to accomplish the integral forming such that the flexible component is coupled with the substantially rigid component in an intimately adhering way (i.e. the components cannot be manually separated).
• In an especially preferred embodiment of the invention, at least one of the flexible components of the respiratory mask is a sealing cushion. The sealing cushion is preferably integrally formed onto the substantially rigid component in such a way that an intimate adhesive bond results. The bonding geometries of the substantially rigid component and the flexible components as well as other factors may be manipulated to provide a required level of adhesion.
• According to another embodiment of the invention, there is provided a respiratory mask for administering a breathable gas to a patient, the respiratory mask comprising a) a first component formed from an elastomeric material; and b) a second component formed from a material that is less flexible than the elastomeric material, wherein the first component is integrally formed onto the second component.
• According to another embodiment of the invention, there is provided a respiratory mask comprising a substrate made of a relatively rigid material, wherein the substrate includes at least one treated portion inclined to accept a reactive substance; and an elastomer that is made of a relatively more flexible material compared to the relatively rigid material of the substrate, said elastomer being applied to the substrate and secured to the substrate via an induced adhesive bond formed between said treated portion and a surface of the elastomer abutting the treated portion.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask, comprising: providing an elastomeric material for forming into a first component; providing a second component that is less flexible than the elastomeric material in a mould; and integrally forming the elastomeric material onto the second component within the mould in order to form the first component.
• The first component can be manually separated from the second component, or the first component is joined to the second component in an intimately adhering manner. The method may further comprise pre-treating the second component to strengthen adhesion between the first and second components. The pre-treating step may comprise applying plasma, preferably an atmospheric plasma treatment, to a bonding surface of the second component. Corona treatment is an alternative. The integral forming may be carried out in an injection moulding tool.
• According to another embodiment of the invention, there is provided a mould for a respiratory mask for administering a breathable gas to a patient, the respiratory mask comprising a first component formed from an elastomeric material; and a second component formed from a material that is less flexible than the elastomeric material, wherein the first component is integrally formed onto the second component, wherein the mould comprises a mould cavity in which the first component is moulded onto the second component.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a mask frame and an elbow provided to the frame, and wherein the elbow or frame includes at least one selected portion including said substrate, and the method further comprises overmoulding said elastomer onto the selected portion.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a mask frame, a cushion provided to the frame and a forehead support positioned above the frame, wherein the mask comprises a flexible portion coupling the frame and the forehead support, the flexible portion including a structural member including said substrate and at least one disc or tube including said elastomer.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a mask frame made at least in part from said elastomer and a retaining ring including said substrate, wherein the method further includes overmoulding the frame onto the ring.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask comprises a frame and a cushion and a headgear assembly to support the frame and cushion, wherein the headgear assembly includes a yoke associated with a strap and a seal ring provided to the yoke, wherein the yoke includes at least one selected portion including the substrate and the method comprises co-moulding the seal ring onto the yoke.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a frame and a gas washout vent having at least one hole or pore, wherein the frame includes at least one selected portion including the substrate and the method comprises co-moulding the gas washout vent onto the frame.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a frame having an aperture and a plug provided to close the aperture, the frame including at least a selected portion including said substrate and the method comprise overmoulding the plug onto the frame.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a conduit including said substrate and a wall member formed at least in part by said elastomer, and said method further comprises overmoulding the wall member and the reinforcement member.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the frame includes a port portion and a port cap provided to the frame, wherein the port portion includes at least a selected portion including the substrate and the method further comprises overmoulding the port cap onto the frame.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein said mask includes a frame with said substrate and a bladder is provided to the frame and formed at least in part from said elastomer.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a frame including at least one port, and nasal cannulae, wherein the frame includes said substrate and the cannulae are formed at least in part from the elastomer, the cannulae being in communication with the port.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a frame, a cushion, a forehead support positioned above the frame, and a forehead pad provided to the forehead support, the forehead pad including said elastomer and the forehead support including said substrate.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a mask frame including the substrate and a mask cushion including the elastomer, wherein the frame includes a peripheral region and the cushion includes a T-shaped or L-shaped rim overmoulded to the frame.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a mask frame including the substrate and a mask cushion including the elastomer, in which the mask frame and the mask cushion form at least one of a diagonal joint, a lap joint and/or a V-joint.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a frame and a cushion, the cushion having an expandable bladder having an interior defined by an interior surface of the elastomer and a portion of the frame that is not treated, and the frame includes a port to allow introduction of a substance delivered to the interior to expand the bladder.
• According to another embodiment of the invention, there is provided a method for manufacturing a respiratory mask comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the mask includes a mask frame a cushion and a cushion clip to secure the cushion to the frame, wherein the substrate is provided as part of the cushion clip and the cushion includes the elastomer.
• According to another embodiment of the invention, there is provided a humidifier tub for a flow generator comprising a substrate made of a relatively rigid material, wherein the substrate includes at least one treated portion inclined to accept a reactive substance; and an elastomer that is made of a relatively more flexible material compared to the relatively rigid material of the substrate, said elastomer being applied to the substrate and secured to the substrate via an induced adhesive bond formed between said treated portion and a surface of the elastomer abutting the treated portion wherein the humidifier tub includes a lid having said substrate and a seal made in part from said elastomer.
• According to another embodiment of the invention, there is provided a method for manufacturing a humidifier tub comprising forming a substrate made of a relatively rigid material; and overmoulding an elastomer to or with the substrate, wherein the humidifier tub includes a lid having said substrate and a seal made in part from said elastomer.
• According to another embodiment of the invention, there is provided a humidifier tub comprising a substrate made of a relatively rigid material; and an elastomer overmoulded with or to the substrate, wherein the humidifier tub includes a lid having said substrate and a seal made in part from said elastomer.
• These and other aspects will be described in or otherwise apparent from the following detailed description of embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
• Embodiments of the invention will now be described with reference to the accompanying exemplary drawings, in which:
• FIG. 1 is a side, partial cross-sectional view of a respiratory mask according to a first embodiment of the present invention shown in situ on a patient's face;
• FIG. 2 is a cross-sectional perspective view of a respiratory mask according to a second embodiment of the present invention;
• FIG. 3 is a cross-sectional perspective view of an enlarged portion of the frame/cushion interface of the respiratory mask ofFIG. 2 and illustrates the bonding configuration therebetween;
• FIG. 4 is a cross-sectional perspective view of an enlarged portion of the frame of the respiratory mask ofFIG. 2 and illustrates an elastomer component disposed over and bonded around a peripheral frame channel and in an inwardly disposed configuration;
• FIG. 5 is a cross-sectional perspective view of an enlarged portion of the frame of the respiratory mask ofFIG. 4 and illustrates the elastomer component in an outwardly disposed configuration;
• FIG. 6 is a schematic, side, cross-sectional view of a cushion to frame connection according to a third embodiment of the present invention;
• FIG. 7 is a side, partial cross-sectional view of the respiratory mask ofFIG. 1 and illustrates the forehead pad in cross-section;
• FIG. 8 is a side, partial cross-sectional view of the respiratory mask ofFIG. 1 and illustrates a flexible portion between the frame and forehead support according to an embodiment of the present invention;
• FIG. 9 is a side, partial cross-sectional view of a respiratory mask according to a fourth embodiment of the present invention and illustrates a flexible portion that incorporates a conduit section therethrough;
• FIG. 10 is a perspective exploded view of a respiratory mask frame, elbow and elbow retaining clip according to a fifth embodiment of the present invention illustrating a bonded elastomer sealing portion on the elbow;
• FIG. 11 is a perspective exploded view of a respiratory mask frame, elbow and elbow retaining clip according to a sixth embodiment of the present invention illustrating a number of additional bonded elastomer sealing portions on the socket and retaining clip;
• FIG. 12 is a perspective exploded view of an elbow of a respiratory mask according to a seventh embodiment of the present invention illustrating a number of bonded elastomer sealing portions;
• FIG. 13 is a perspective view of a portion of a respiratory mask frame and elbow according to a eighth embodiment of the present invention;
• FIG. 14 is a perspective, cross-sectional view of the portion of the frame and elbow ofFIG. 13;
• FIG. 15 is an enlarged, perspective, cross-sectional view of the frame and elbow ofFIG. 13 illustrating the elbow sealing arrangement;
• FIG. 16 is a perspective view of a portion of a respiratory mask frame and elbow according to a ninth embodiment of the present invention;
• FIG. 17 is a perspective, cross-sectional view of the portion of the frame and elbow ofFIG. 16;
• FIG. 18 is an enlarged, perspective, cross-sectional view of the elbow ofFIG. 16 illustrating the elbow sealing arrangement;
• FIG. 19 is a perspective, cross-sectional view of a portion of the respiratory mask frame and elbow ofFIG. 16;
• FIG. 20 is a perspective view of a portion of a respiratory mask frame and elbow according to an tenth embodiment of the present invention;
• FIG. 21 is a perspective, cross-sectional view of the portion of the frame and elbow ofFIG. 20;
• FIG. 22 is an enlarged, perspective, cross-sectional view of the frame and elbow ofFIG. 20 illustrating the elbow sealing arrangement;
• FIG. 23 is a perspective view of a portion of a respiratory mask frame and elbow according to a eleventh embodiment of the present invention;
• FIG. 24 is a perspective, cross-sectional view of the portion of the frame and elbow ofFIG. 23;
• FIG. 25 is an enlarged, perspective, cross-sectional view of the frame and elbow ofFIG. 23 illustrating the elbow sealing arrangement;
• FIG. 26 is a perspective view of a portion of a respiratory mask frame and elbow according to a twelfth embodiment of the present invention;
• FIG. 27 is a perspective, cross-sectional view of the portion of the frame and elbow ofFIG. 26;
• FIG. 28 is an enlarged, perspective, cross-sectional view of the frame and elbow ofFIG. 26 illustrating the elbow sealing arrangement;
• FIG. 29 is a perspective view of a portion of a respiratory mask frame and elbow according to an thirteenth embodiment of the present invention;
• FIG. 30 is a perspective, cross-sectional view of the portion of the frame and elbow ofFIG. 29;
• FIG. 31 is an enlarged, perspective, cross-sectional view of the frame and elbow ofFIG. 29 illustrating the elbow sealing arrangement;
• FIG. 32 is a perspective, exploded view of an elbow and a frame having a flexible enclosure, a rigid elbow connection ring defining an aperture in the frame and a rigid surrounding portion according to a fourteenth embodiment of the present invention;
• FIG. 33 is a perspective, exploded view of an elbow, frame and headgear member according to a fifteenth embodiment of the present invention;
• FIG. 34 is a side, partial cross-sectional view of a respiratory mask according to a sixteenth embodiment of the present invention and illustrates a vent;
• FIG. 35 is a perspective exploded view of a respiratory mask frame and vent plug according to a seventeenth embodiment of the present invention;
• FIGS. 36(a)-36(d) are schematic diagrams showing three types of conduit reinforcing structure according to eighteenth, nineteenth, twentieth and twenty first embodiments of the present invention, respectively;
• FIG. 37 is a side, cross-sectional view of a ports cap configured on a frame of a respiratory mask according to a twenty-second embodiment of the present invention;
• FIG. 38 is a perspective, exploded view of a frame, elbow and elbow retaining clip including a plurality of gripping portions according to a twenty third embodiment of the present invention;
• FIG. 39 is a perspective view of a frame including a large gripping portion according to a twenty-fourth embodiment of the present invention;
• FIG. 40 is a perspective view of a frame including a detachable conduit arrangement according to a twenty-fifth embodiment of the present invention;
• FIG. 41 is a perspective view of a flow generator including a humidifier tub having a lid according to a twenty-sixth embodiment of the present invention;
• FIG. 42 is a perspective view of the lid ofFIG. 41 showing a recess configured to receive a seal;
• FIG. 43 is a perspective view of a lid seal for the lid ofFIG. 41;
• FIG. 44 is a non-vented full face mask according to an embodiment of the present invention;
• FIG. 45 is a schematic cross-sectional view of a portion ofFIG. 44 showing an elbow-to-frame interface/seal according to a first variant;
• FIG. 46 is a schematic cross-sectional view of a portion ofFIG. 44 showing an elbow-to-frame interface/seal according to a second variant;
• FIG. 47 is a schematic cross-sectional view of a portion ofFIG. 44 showing an elbow-to-frame interface/seal according to a third variant;
• FIG. 48 is a perspective view of an elbow having elastomer seals according to an embodiment of the present invention;
• FIG. 49 is an exploded perspective view of a test ring having a seal for insertion within a receptacle according to an embodiment of the present invention;
• FIGS. 50-53 illustrate partial cross-sectional views of plug seals according to embodiments of the present invention; and
• FIG. 54 illustrates a schematic diagram of a mould system according to an embodiment of the present invention.
DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS OF THE INVENTION5.0 Introduction5.0.1 Definitions5.0.1.1 “Overmoulding”
• The word “overmoulding” is used in this specification in its broadest sense, that is, in the sense of moulding one component onto another component, or integrally forming two components. A number of different moulding processes that are deemed to fall within the ambit of the word ‘overmoulding’ as used in this specification are described below. It should be appreciated that this group of moulding processes is inclusive and not exhaustive.
• Overmoulding is used to refer to the process of forming a bond between a first material, known as the “substrate material”, and a second material known as the “overmould”. However, the word ‘overmoulding’ also refers to moulding where no bond or substantive bond is formed but where respective components are held together, for example, only by a mechanical interlocking, keying or undercut. Mechanical interlocking can be either macroscopic (e.g., undercuts) or microscopic (e.g., depending on abrasion of the substrate).
• The word ‘overmoulding’ also refers to a type of moulding where the two materials to be joined are inserted into the mould at the same time or at two points in time close together. For example, overmoulding includes “overmoulding” or “co-injection moulding”. A co-injection moulding process involves a first step where a first component (e.g., substrate) is moulded in a first mould and once ejected progresses to a second step where the first component is placed inside a second mould for the moulding of a second component (e.g., elastomer) on to it. In between the moulding steps, the first component may be treated to more readily accept a reactive substance. Treatment may take the form of plasma treatment, for example, and this treatment may take place within the mould(s) or outside the moulds. What distinguishes co-injection moulding from other types of overmoulding is that when the first component is being progressed through the second step another first component is being manufactured by the first step. That is, the first and second steps are being performed simultaneously for sequentially manufactured products. This can be achieved with a rotating tool set (e.g., a turntable with two or more moulding stations) or robotic arm.
• ‘Overmoulding’ also refers to “Moving Cores Moulding” where one injection moulding machine fitted with two injection systems is used. Once the substrate has cooled sufficiently a section of the tool retracts, forming a cavity for the overmould material. Moving cores have conventionally been best suited to simple overmoulds, where a uniform thickness of overmould is required.
• “Rotating Platen or Stripper Plate” moulding is also considered a overmoulding process. This process involves rotation of the tool once the substrate has cooled. A rotating platen rotates the component on its core, whereas a rotating stripper plate lifts the component off its core before rotating. The main advantage of these methods is that they allow a different shaped cavity or core to be used to form the overmould. More sophisticated components can be created using this method.
5.0.1.2 “Flexible Material/Component”
• The words “flexible material/component” as used in this specification include any material with physical properties similar to or the same as an elastomer material which is defined in the Webster's New World Dictionary as, “a rubber-like synthetic polymer, as silicone rubber”. Therefore, a rubber, a natural polymer or any other rubber-like material including some gels are included within the scope of the words “flexible material/component”.
• The words “flexible material/component” also refer to various mixtures of individual elastomer components. These elastomers may be pre-mixed or mixed in the mould. Examples of elastomers are liquid silicone rubber (LSR), solid silicone rubber and thermoplastic elastomers (TPEs).
5.0.1.3 “Substantially Rigid Component”
• A substantially rigid component includes all materials that are less flexible than the flexible material. Examples of substantially rigid components are polycarbonate (e.g. Lexan) and phenol formaldehyde (e.g. Bakelite.)
5.0.2 Bonding
• There are 2 main types of bond: adhesive (an interfacial property) & cohesive (a bulk property). This application is largely concerned with the former rather than the latter.
• There are several different types of adhesive bonding:
• • adsorption bonding depends on intermolecular attractive forces between adhesive and substrate (e.g. Van der Waals forces)
  • chemical bonding depends on available functional groups on the substrate surface and their reactivity with the molecules of the adhesive. Also known as covalent bonding.
  • diffusion bonding depends on the mutual solubility between the substrate and adhesive
  • electrostatic bonding depends (typically for solids) on dipole-dipole interactions.
• Ideally, the adhesive strength of the bond formed in embodiments of the invention is significantly greater than the cohesive strengths of the components thereof. The level of adhesion achievable is dependent on the preparation of the bonding surface areas, amongst other factors. A pretreatment may be applied to a selected bonding area of the substantially rigid component to enhance adhesion.
• One such pretreatment is the application of plasma, such as an atmospheric plasma treatment, to the bonding area of the substrate. Plasma treatment chemically activates the bonding area to enhance chemical bonding. Plasma treatment is effected by blasting highly energized gases at the surface which causes reactive molecules to be embedded in the surface. These molecules form a bond with the relatively less rigid component, e.g., in the case of silicone, a polydimethyl siloxane bond may be formed. The gas is typically compressed air, but it can be nitrogen or other gases. It should be noted that the longer a plasma treated surface is left before bonding, the less effective the treatment will be. Plasma treatment is described in “Plasma Processes and Polymers” by d'Agostino et al., published by Wiley, 2005.
• One method of applying plasma treatment is to position a masking sheet or stencil over the surface to which the plasma is to be applied. One or more aperture(s) in the stencil allows the plasma to contact the portion of the surface to be bonded but masks the remainder of the surface. An alternative to use of a masking sheet is the use of a finely controllable plasma gun (e.g. a gun mounted on an apparatus controllable by a computer such as a robotic arm).
• Examples of commercially available atmospheric plasma guns include Atomflo™ by Surfx Technologies LLC of USA and PlasmaTEC™ by Dyne Technology Ltd of UK.
• One alternative to plasma treatment is corona treatment, which typically is a stronger treatment which requires more energy and affects the substrate differently.
• A further alternative to plasma treatment is chemically treating the surface by, for example, the application of adhesion promoters, such as silane coupling agents. Another chemical pre-treatment is the application of a solvent to the surface.
• Yet another alternative is to use self-adhesive elastomeric material and to apply a non-bonding material (e.g. silicone grease) or contaminant, where a bond is not desired.
• A further variation is flame oxidization of the surface.
• Advantageously, all these pre-treatment processes allow treatment of only selected areas as required, by masking or otherwise avoiding areas where bonding is not desired.
• Adhesion strength is also dependent on timing. A better bond may be formed when the second component is moulded onto the first component if the temperature of the first component is still raised. In the case that a chemical bond is not required, temperature differences and the resulting shrinkage differential may improve mechanical interlocking.
• Often when an overmoulding process is used, the substantially rigid component will be moulded with a slight recess around the periphery of the bonding area to assist bonding with the flexible material by providing a level of mechanical interlocking as well as a larger bonding area. Furthermore, bonding along multiple planes with respect to forces applied may assist in reducing adhesive failure.
5.1 General Structure of a Respiratory Mask
• Arespiratory mask2A is shown inFIG. 1 in situ on the face of auser1000. Themask2A comprises aframe4A, formed from a substantially rigid component, such as a polycarbonate material, a sealingcushion6A formed from an elastomeric material, such as liquid silicone rubber (LSR), and aforehead support8A, which is adjustably coupled to theframe4A via aflexible portion10A. Theforehead support8A includes aforehead pad12A, made from an elastomeric material.
5.2 Sealing Cushion
• Thecushion6A has been co-moulded onto aperipheral portion14A of theframe4A. In this example, theframe4A was pretreated such that thecushion6A forms a high-strength adhesive bond with theframe4A.
• Thecushion6A includes alip16A that is curved inwardly and terminates in anaperture18A that is sized and shaped for receiving at least part of the nose of a patient. Thelip16A traverses anupper lip region1002 of theuser1000 in the case that themask2A is configured as a nasal mask or achin region1004 of theuser1000 in the case that themask2A is configured as a full-face mask. Although themask2A only incorporates asingle lip16A, it should be appreciated that multiple lips could be incorporated. Gel structure(s) may also be incorporated intolip16A, or in the case that multiple lips are provided into each lip. Alternatively, thelip16A could be replaced with one or more gel structures.
• Moulding thecushion6A to theframe4A eliminates the need for a cushion-to-frame securing component and the associated assembly step. This reduces the cost of goods and/or may assist in improving compliance with therapy.
5.2.1 Bonding Configurations
• Various bond configurations are possible. In one embodiment, shown inFIGS. 2 and 3, thecushion6B of arespiratory mask2B has a T-shapedrim20B that is sized to be bonded to aperipheral region22B of theframe4B. The T-shapedrim20B provides abonding surface24B that is larger than it would otherwise be if no T-shapedbonding rim20B was provided. Thislarger bonding surface24B allows a stronger bond to form. Alternatively, an L-shaped bonding rim could be provided. However, the T-shapedbonding rim20B is advantageous with respect to the L-shaped rim because when thecushion6B is pulled away from theframe4B, no bending moment is created. A bending moment could assist a tear developing through the bond. Other suitable bonding configurations include a diagonal joint, a lap joint and a V-joint. Furthermore, the bonding could occur on an interior surface offrame4B, e.g., a lap joint.
5.2.2 Bonding to Form Bladders
• Referring toFIGS. 4 and 5, selective bonding can be utilized to form abladder26B that can be expanded. Thebladder26B can be expanded by delivery of pressurized air to aport30B. The stenciling or masking procedure described in Section 5.0.2 may be utilized to chemically activatebonding areas32B where sides of thewall34B of thebladder26B join theframe4B. Thebonding areas32B adhere to the portions of the cushion in contact with the bonding areas, while the surface of thebladder26B is free to separate from theframe4B since those portions of the frame have not been treated. The pressurized air may be pressurized to 2 bar or any other suitable pressure. Furthermore, gases other than normal air could be used to pressurize thebladder26B. Alternatively, a gel, foam, liquid or other soft substance may be inserted into thebladder26B instead of a gas, such that a soft, flexible pad is formed. The pad may be filled and permanently sealed or be releasably or temporarily sealed. The inside surfaces of the pad may be provided with a permeation-resistant liner.
• In one embodiment, the gel cushion could be provided using a skin made of LSR that is filled with a gel, e.g., silicone. To prevent the gel from permeating through the LSR skin, the inside surface of the skin could be coated with a liner, such as polyester and/or polyurethane. The liner could be applied using any number of techniques, e.g., spraying (just before the gel is introduced, e.g., inFIG. 5), co-moulding, dipping, brushing, etc.
• Referring toFIG. 6, an alternative reinforcedbladder arrangement36C is shown. In this arrangement thecushion6C is not directly formed onto theframe4C but is co-moulded to aclip38C. Theclip38C is attachable to theframe4C by a mechanical interlock. Thecushion6C may also be bonded to theclip38C in a manner such that when attached to theframe4C, a portion of thecushion6C is sandwiched between theframe4C andclip38C providing a mechanical interlock. Theclip38C is configured with a reinforcingmember40C for supporting and stabilizing an undersurface42C of thecushion6C. This limits rotation/movement of thecushion6C on the face of the user.
5.3 Forehead Support
• Referring now toFIG. 7, theforehead support8A andforehead pad12A may be embodied as co-moulded components. Theforehead pad12A is formed by injection-moulding an elastomeric material onto theforehead support8A which is made from a dimensionally stable plastic material, such as a polycarbonate. Aslot44A is formed in theforehead pad12A during the overmoulding process by virtue of the shape of theforehead support8A. Theslot44A provides a mechanical interlock such that theforehead support8A can be releasably secured to theforehead support8A. There is no intended or significant adhesive bond between theforehead support8A andforehead pad12A in this embodiment. This may be achieved by not using a surface pre-treatment and/or overmoulding the parts once theforehead support8A is completely set (i.e. after moulding). The benefit of not including a substantive bond in this instance is that the forehead support can be removed for separate cleaning or replaced with a new or different type of forehead support.
• Advantageously, overmoulding theforehead pad12A to theforehead support8A eliminates the assembly step of mounting theforehead pad12A to theforehead support8A, reducing the cost of goods and increasing convenience to the patient.
5.4 Flexible Portion
• Theflexible portion10A will now be described with reference toFIG. 8. Theflexible portion10A comprises a structural spine50A and a number ofelastomer discs52A that have been co-moulded onto the spine50A and between theframe4A and the spine50A. Because theelastomer discs52A are flexible, theframe4A is able to articulate with respect to theforehead support8A. Theelastomer discs52A may be made from the same elastomer material that thecushion6A is made out of or from a different flexible material. In an alternative embodiment theelastomer discs52A comprise bladders formed from an elastomeric material (or otherwise) that are filled with a compressed gas, liquid or soft solid such as foam, gel or mineral particles.
• FIG. 9 shows another embodiment of amask2D having aflexible portion10D including anelastomer tube56D around which a lessflexible exoskeleton58D is disposed. The ends60D &62D of theelastomer tube56D have been comoulded to theframe4D andforehead support8D, respectively. This arrangement allows theframe4D to articulate with respect to theforehead support8D, and consequently, thecushion6D to rotate and move to a degree with respect to the patient's face. This means that themask2D is able to provide a better seal against the patient's face. This elastic deformation behavior can be varied by changing the wall thickness or wall section of theexoskeleton58D.
• Theelastomer tube56D may be made from the same elastomer material that thecushion6D is made out of or from a different flexible and co-mouldable material.
• In this case, theelastomer tube56D provides a fluid passageway that extends between an inner region of theframe4D and theforehead support8D where the fluid passageway terminates in aconnection66D. Theconnection66D is adapted for receiving one end of a conduit (not shown) that is in fluid communication with an outlet port of a flow generator (not shown).
• A mask in accordance with other embodiments of this invention may include a translatable adjustment rather than a rotatable adjustment.
5.5 Elbow & Frame Socket
• Referring toFIG. 10, amask2E is shown which has aframe4E that comprises asocket68E that is adapted to receive afirst end70E of anelbow72E. Thefirst end70E of theelbow72E is swivel mounted to thesocket68E and theelbow72E provides fluid communication between a conduit (not shown) and themask2E. Aclip74E is provided to thefirst end70E of theelbow72E to retain it in thesocket68E in use.
• InFIG. 10 thesecond end76E of theelbow72E has anelastomer portion76E co-moulded thereto to provide an improved connection and seal with the conduit to which it is attached. In an alternative embodiment (not shown), the conduit has an elastomer sealing portion rather than thesecond end76E.
• Referring toFIG. 11 the socket68G has a dimensionallyrigid material portion78G and an elastomer portion80G co-moulded onto an inner surface thereof. The elastomer portion80G provides a better seal with thefirst end70G of the elbow72G in use. The clip74G also includes anelastomer portion88G co-moulded thereon. This provides a more acoustically pleasing clipping sound.
• FIG. 12 illustrates anelbow72H generally similar in design and construction to the elbow ofFIGS. 10 & 11 in its component parts. Theelbow72H features a number ofelastomer portions90H that serve to aid sealing, dampening, the reduction of rattle and/or the tactility and acoustics of connecting parts.
• A number of different elbow-to-frame sealing arrangements will now be described. These are suitable for use on a variety of masks. Following this a sealing elbow arrangement for the ResMed Meridian mask [U.S. Provisional Patent Application No. 60/682,827] and a sealing arrangement for the ResMed Swift mask [U.S. Provisional Patent Application No. 60/734,282] will be described, each incorporated by reference in its entirety.
5.5.1 Two Stage Radial Elbow to Frame Seal A
• FIGS. 13 to 15 show a two stage radial seal92I comoulded to an elbow72I and adapted to seal against a frame4I. The seal92I comprises a long elastomer lip94I that abuts an inner surface84I of a socket68I of a frame4I. The seal92I further comprises two shorter lips96I that are moulded in the line of draw. In use, the long lip94I presses into the socket68I and flexes back onto the two shorter lips96I such that the long lip94I is supported in a position where it abuts and seals against the socket68I. This geometry accommodates misalignment of the elbow72I with respect to the frame4I.
• The elbow72I further incorporates three circumferential flanges. A first flange98I is integrally moulded to the elbow72I to prevent the seal92I from contacting any flat supporting surface when the elbow72I is disassembled from the frame4I. This minimises risk of damage to the seal92I during transport, storage and cleaning. A second flange100I is provided on the elbow72I and engages the socket68I to stabilize theelbow681. While in this embodiment the second flange100I is located inboard from the seal92I, in other embodiments it could be moved outboard providing a greater moment arm. A third flange102I is positioned within the socket68I to engage a shoulder103I of the elbow4I, adjacent where the socket68I begins to extend beyond the outer surface104I of the frame4I.
• Another embodiment (not shown) is also provided where only a line contact seal is provided to the frame4I as opposed to an area contact seal. A line contact seal reduces the torque required to rotate the elbow with respect to the frame.
• It should also be noted that this design avoids undercuts and crevices to ensure ease of cleaning.
• FIG. 13 also depicts an anti-asphyxia valve having a base portion103I that is co-moulded to an elbow clip105I of the elbow72I. This overmoulding step replaces an assembly step reducing the cost of goods and increasing convenience to the patient.
5.5.2 Two Stage Radial Elbow to Frame Seal B
• The embodiment shown inFIGS. 16 to 19 includes aseal106J that is similar to theseal921 ofFIGS. 13-15 except that the seal geometry has been altered to provide less contact area between theseal106J and theframe4J. Theseal106J comprises along elastomer lip94J and oneshorter lip96J that are moulded in the line of draw. Thelong lip94J presses into the socket68J of theframe4J and flexes back onto theshorter lip96J such that thelong lip94J is supported in a position abutting and sealing with theinner surface84J of the socket68J. This geometry accommodates misalignment of theelbow72J with respect to theframe4J.
• Theelbow72J incorporates three circumferential flanges to stabilize theelbow72J within the socket68J. Afirst flange98J is positioned outside the socket68J and frame4J. Thefirst flange98J prevents theseal106J from contacting any flat surface when theelbow72J is disassembled from theframe4J thereby reducing the risk of damage to theseal106J during transport, storage and cleaning. Asecond flange100J is positioned outside the socket68J and inside theframe4J and abuts the socket68J to stabilize the elbow68J. Athird flange102J is positioned within the socket68J adjacent where the socket68J begins to extend beyond theouter surface104J of theframe4J.
• Another embodiment (not shown) is also provided where only a line contact seal is provided to theframe4J as opposed to an area contact seal. A line contact seal reduces the torque required to rotate the elbow with respect to the frame.
• This design avoids undercuts and crevices to ensure ease of cleaning.
5.5.3 Single Radial Seal
• Referring to themask2K ofFIGS. 20-22 anelbow72K is provided having a singleradial lip seal108K that acts on aninner surface84K of asocket68K. Theelbow72K incorporates four circumferential flanges to support and stabilize theelbow72K on theframe4K. Afirst flange98K is positioned outside thesocket68K and frame4K. Asecond flange100K is positioned outside thesocket68K and inside theframe4K. A third and fourth flange,102K &110K respectively, are positioned on either side of theseal108K. This design avoids undercuts and crevices to ensure ease of cleaning.
5.5.4 Double Radial Seal
• FIGS. 23 to 25 show amask2L incorporating a doubleradial seal112L. The doubleradial seal112L has twolips114L &116L, respectively, adjacent each other, that seal against aninner surface84L of asocket68L of aframe4L. Eachlip114L,116L is configured with a generally triangular cross-section such that it has a degree of stiffness to enhance sealing.
• Theelbow72L incorporates threecircumferential flanges98L,100L &102L that are arranged in the same fashion as the embodiment of Section 5.5.1 andFIGS. 13-15. This design avoids undercuts and crevices to ensure ease of cleaning.
5.5.5 External Seal
• The embodiment shown inFIGS. 26-28 provides 3 sealing zones between theelbow72M and thesocket68M. The 3 sealing zones include aradial seal114M disposed on theelbow72M inside thesocket68M, anaxial seal116M that seals against anend face118M of thesocket68M and an externalradial lip seal120M that seals against an outside thesocket68M.
• Theelbow72M incorporates fourcircumferential flanges98M,100M,102M and103M to stabilize and support theelbow72M within thesocket68M. Additionally, thefirst flange98M of the circumferential flanges is sized and adapted to prevent theseal120M from contacting any flat supporting surface when theelbow72M is disassembled from theframe4M. This minimises risk of damage to theseal120M during transport, storage and cleaning.
5.5.6 Radial & Axial Seal Combination
• Referring toFIGS. 29-31 asealing arrangement122N is shown. The sealingarrangement122N comprises aradial lip seal124N of triangular cross-section that seals against aninner surface84N of thesocket68N and anaxial lip seal126N that seals against anend face118N of thesocket68N.
• The elbow incorporates the same arrangement of three circumferential flanges for stabilization of theelbow72N within thesocket68N as is provided in the embodiment ofFIGS. 13-15 described in Section 5.5.1.
5.5.7 ResMed Meridian Mask [U.S. Patent Application No. 60/682,827]
• The contents of U.S. Patent Application No. 60/682,827 are incorporated herein by reference in their entirety. Referring toFIG. 32, the ResMed Meridian Mask Assembly2O comprises a flexible silicone frame4O having a hard peripheral portion127O, a polycarbonate elbow72O and a retaining ring128O that is used to connect the frame4O to the elbow72O and allow them to swivel relative to each other.
• The elastomer frame4O can be overmoulded to the retaining ring128O. This ameliorates any difficulties encountered in mounting the ring128O on the frame4O and takes away the step of connecting the two parts during assembly.
5.5.8 ResMed Swift Mask Elbow [U.S. Patent Application No. 60/758,200]
• The contents of U.S. Patent Application No. 60/758,200, filed Jan. 12, 2006 are incorporated herein by reference in their entirety. Referring toFIG. 33, a portion of aResMed Swift Mask2P is shown including acushion assembly6P,yoke130P that is attached to a headgear strap, seal132P andelbow72P. Theyoke130P includes ayoke ring134P that is adapted to surround a portion of theseal132P and theseal132P is adapted to surround a portion of theelbow72P. Thecushion assembly6P may be adjustably rotated with respect to theyoke130P.
• Seal132P may be overmoulded to theyoke ring134P. This ameliorates difficulties sometimes encountered in mounting theseal132P on theyoke ring134P and takes away the step of connecting the two parts during assembly.
5.6 Gas Washout Device
• Referring toFIG. 34, theframe4P includes aco-moulded vent54P for allowing exhaled breath to exit an interior region of theframe4P into the surrounding environment. Thevent54P is formed from an elastomer material that has been co-moulded to theframe4P. The geometry of theframe4P and vent54P are such that they mechanically engage in a manner that allows thevent54P to be retained or removed from theframe4P, as required.
• In another embodiment, thevent54P is substantially inseparably coupled to theframe4P by a chemical bond in addition to the mechanical interlock. The vent may also be embodied as an insert that comprises a plurality of fluid conduits (or vent holes or pores (e.g., sintering)) that connect the interior region of theframe4P to the surrounding environment.
5.6.1 Sealing a Vented Mask to Make a Non-Vented Mask
• FIG. 35 depicts a ventedmask2Q having a vent aperture54Q and a plug136Q. For ease of visualizationFIG. 35 shows the plug136Q separately from themask2Q but in reality the plug136Q is formed in the vent54Q by overmoulding to form a non-vented mask. In this case, the plug136Q is formed from silicone.
• This process means that a single mask frame4Q is a suitable component for either a vented or a non-vented mask. This reduces manufacturing costs because only one frame4Q needs to be moulded for both types of mask.
• In the case that non-vented therapy is being delivered to a patient, the plug136Q is permanently attached to the frame4Q. Advantageously, this avoids user interference with the equipment (e.g. removal of the plug136Q) and subsequent therapy problems. This permanent attachment may be achieved through the aforementioned plasma pre-treatment. Alternatively, the plug136Q may be temporarily attached, and in this case themask2Q could be used to provide either vented or non-vented therapy.
5.7 Conduit
• Methods of conduit manufacture utilizing overmoulding will now be described. The fundamental technical issues addressed by the overmoulding technique in the context of conduits is the development of a conduit which is both flexible yet does not occlude in use. Overmoulding allows a flexible membrane conduit wall to be attached or bonded to a less flexible conduit structure, the purpose of which is to prevent occlusion of the flexible wall.
• In one embodiment, the conduit structure is configured as a reinforcement structure, e.g., an exoskeleton over/within, and/or inside the flexible conduit wall. Clearly, where the conduit structure extends continuously along the conduit wall, the conduit structure must be formed of a flexible material to allow the conduit to bend. Fastening of the flexible wall to the conduit structure may be achieved by either mechanical engagement, molecular bonding or both.
• Three embodiments of conduit structures are shown inFIGS. 36(a)-36(c). The first, shown inFIG. 36(a), is a helical conduit structure140S that provides significant torsional strength. Thesecond conduit structure140T, shown inFIG. 36(b), comprises a plurality ofcircular ribs142T interconnected bylongitudinal members144T that are provided on alternating opposing sides of the conduit wall (not shown).FIG. 36(c) depicts athird conduit structure140U comprising a plurality ofcircular ribs142U interconnected by duallongitudinal members144U that are provided on opposing sides of the conduit wall (not shown).FIG. 36(d) depicts a fourth conduit structure145.
5.8 Ports Cap
• FIG. 37 shows aports cap146V co-moulded to theframe4V. The ports cap146V comprises acover portion148V and ahinge portion150V that is permanently bonded to anadhesion region152V of theframe4V. Thecover portion148V is only lightly or marginally bonded to theframe4V and can be readily manually separated by a user or clinician the first time the ports cap146V is used. Advantageously, the ports cap146V cannot be dropped by a patient or lost. The ports cap146V can be designed so that it can be reattached to theframe4V even though the light bond is broken (e.g. by a mechanical interlock such as a rib and groove arrangement).
5.9 Mask Surfaces5.9.1 Gripping
• Manual gripping of mask parts made of hard materials with smooth surfaces (e.g. polycarbonate) can be difficult. This can lead to slippage or movement during manipulation of mask parts. The integration of elastomeric regions onto a mask, and in particular onto a mask frame, assists both manual and robotic gripping. Elastomeric regions may be integrated into a mask solely for this purpose and may provide robots with a controlled grip to handle mask parts for automation, assembly or packaging purposes.
• An example of how gripping regions might be incorporated into amask frame4W andelbow72W is illustrated inFIG. 38. A number of smallgripping regions152W are co-moulded onto each side of theframe4W and at least one relatively largegripping region154W is co-moulded onto each side of theelbow72W. Theelbow gripping regions72W assist: (1) gripping of theelbow72W during manufacture, and/or (2) removal of theelbow72W from theframe4W by a patient or clinician.
5.9.2 Soft Touch
• Other mask embodiments include one or more soft touch surface(s) co-moulded to the mask frame. The soft touch surface(s) feels nicer and less clinical to a patient than a hard surface(s) (e.g. polycarbonate). By varying the thickness and hardness of a soft touch surface, a range of different feels may be provided. Other parts of respiratory masks may also include soft touch surfaces such as the headgear clips or forehead support.
5.9.3 Branding
• Co-moulded elastomer regions also provide suitable surfaces for the placement of product or company branding or logos, e.g., “ResMed” could be spelled out by co-moulding onto various mask components such as the frame, headgear, forehead support, elbow, etc. In one embodiment, the branding indicia is embossed into the elastomer or the elastomer forms the branding indicia. It should be noted that any one elastomer region could be used for a multiplicity of purposes, such as more than one of gripping, soft touch and branding. The elastomer could also be coloured to improve aesthetics, or for branding purposes etc.
5.10 Other Overmoulding Applications for Masks5.10.1 Mask Volume Reduction Bladder
• Referring toFIG. 39, a mask volume reduction bladder (MVRB)156Y may be incorporated into amask frame4Y by overmoulding an expandable pocket onto aninterior surface158Y of theframe4Y, and more particularly, overmoulding aperipheral edge160Y of the pocket to theinterior surface158Y of theframe4Y. Thebladder156Y is positioned and configured such that it is expandable to occupy at least a portion of the gas dead space within the mask. In this particular embodiment, the bladder walls are made from a thin sheet of silicone (0.1-0.6 mm thick).
• The bladder may have elastic properties and in an alternative embodiment may be configured within a recess in the frame instead of on an interior surface of the frame. In one variation, the bladder volume is in fluid communication with an interior volume of the frame via a flap valve or other suitable valve. In yet another variation, the frame includes an air passageway between the interior volume of the frame and the interior volume of the bladder.
• In another embodiment, the bladder inflates and deflates responsive to the breathing cycle of the patient, reducing the volume required to be displaced by the patient's lungs during exhalation. In yet another embodiment, the bladder deflates during exhalation to increase the volume and thus reduce the expiration pressure peak and subsequently the work of breathing. In another embodiment the bladder is co-moulded to an outer surface of the frame and an interior portion of the bladder is in fluid communication with an inner region of the frame (e.g. via an aperture in the frame). During exhalation the bladder can expand and thus reduce the expiration pressure peak and subsequently the work of breathing.
5.10.2 Removable Oxygen Sensing Cannula
• FIG. 40 shows aframe4Z of a respiratory mask incorporatingoxygen cannulae162Z that are formed by overmoulding silicone to an interior surface of theframe4Z. Thecannulae162Z can be peeled away from theframe4Z starting at thecannula exit apertures164Z such that theexit apertures164Z are positioned directly beneath a patient's nares. Thecannulae162Z are in fluid communication withframe ports166Z to which an oxygen delivery conduit (not shown) or gas receiving conduit (not shown) may be attached. A gas receiving conduit might be used to receive exhaled breath in order to detect levels of different gases (e.g. oxygen) in the exhaled breath. Theframe ports166Z are sealed by plugs when thecannulae162Z are not in use and thecannulae162Z may be completely removed (torn off) theframe4Z. The plugs may take the same or similar form to those described in Section 5.8.
5.10.3 Humidifier Tub Seal [U.S. patent application Ser. No. 10/533,940]
• U.S. patent application Ser. No. 10/533,940 is incorporated herein by reference in its entirety. Referring toFIGS. 41-43, a ResMed S8 flow generator168AA is shown comprising a humidifier170AA. The humidifier170AA has a lid172AA, an underside of which is shown inFIG. 42 and includes a recess174AA.FIG. 43 shows an elastomer seal176AA that is adapted to fit in the recess174AA.
• The improvement over U.S. patent application Ser. No. 10/533,940 is that the elastomer seal176AA is co-moulded to the lid172AA about the air exit aperture178AA. This overmoulding provides a stronger mounting of the seal176AA to the lid172AA than a mere mechanical interlock and also ameliorates the problem of biological growth in crevices. The overmoulding can be in the form of a full surface bond or a peripheral bond.
• The improvement ameliorates difficulties sometimes encountered in mounting the seal176AA on the lid172AA and makes the step of connecting the two parts during assembly obsolete.
5.11 Elbow-to-Frame Seal
• FIG. 44 shows a full face mask2.1 having a frame2.2 and an elbow2.3 provided to the frame. Details of the overall mask are described in relation to U.S. patent application Ser. No. 11/027,689, filed Jan. 3, 2005, incorporated herein by reference in its entirety. A seal is formed between the elbow and the frame and may be formed on the frame or the elbow using the overmoulding techniques described herein.
• FIG. 45 shows a seal2.5 that is formed on an inner circumferential portion of the elbow at the base of the frame inlet.FIG. 46 shows a seal2.6 formed on an outer circumferential surface of the elbow.FIG. 47 shows a seal2.7 at the distal end portion of the inlet portion of the frame.
• FIG. 48 includes an elbow with the seals fromFIGS. 47 and 46 All of the seals2.5,2.6 and2.7 can be formed on either the frame and/or the elbow. The seals help decrease leak while at the same time reduce squeak/squeal if the elbow is rotated relative to the frame.
5.12 Alternative Seal Designs
• FIG. 49 is an exploded view of a test rig3.1 including for testing seals that can be used with the elbow-to-frame connections described above.FIGS. 50-53 illustrate various seal geometries.
• FIG. 50 shows a syringe-type seal3.2 that is compressed to fit within the bore, but provides high sealing strength.FIG. 51 shows a blade style seal33. While the main ridge3.4 contacts the bore, the adjacent portions3.5 may also contact the bore depending on the desired amount of rotation force required.FIG. 52 shows an axial flap seal3.6 that engages on an angled face3.7 of the bore.FIG. 53 shows a rubber seal having a generally rectangular cross-section.
5.13 Mould
• A mould for a respiratory mask or humidifier tub is provided in one embodiment of this invention. The substantially rigid component mould provides the substantially rigid component with very small sealing rims around the periphery of the elastomer bonding region and the elastomer mould has corresponding notches that form a tortuous path that is difficult for the liquid elastomer or other material to flow through.FIG. 54 shows a sample rotating mould system4.1 having a turntable4.2 that rotates about an axis4.3. Turntable4.2 includes a first moulding station4.4 for moulding a first component, e.g., the substrate (e.g., frame) and a second moulding station4.5 for moulding a second component, e.g., the elastomer (e.g., cushion, pad, seal, etc.).
5.13.1 Mask Design to Facilitate Removal from Mould
• The respiratory mask is designed such that its substantially rigid components can be demoulded largely without undercuts. The elastomer components may be made by moulding tool structures that produce undercuts. The demoulding of the elastomer components can then be done by elastic deformation of the elastomer components.
5.14 Fully Automated Mask Manufacture
• An automated manufacturing process for a mask is another embodiment of this invention. The automated manufacturing process utilizes overmoulding to manufacture and/or bond appropriate components, in combination with at least one automated assembly step (e.g. fitting the elbow in the socket or attaching the headgear to the headgear clips).
5.15 Advantages5.15.1 Cost Saving
• Overmoulding reduces cost of goods. Components, the only function of which is to hold two other components together are made redundant. Components can also be made from less material when the attachment structure is no longer needed.
• To raise an order with a supplier costs money. There is the cost of the labour of the purchasing officer, as well as the cost of transporting each individual part to the company. Overmoulding allows companies to combine two or more components into one, thus significantly reducing the associated purchasing costs.
• Overmoulding also reduces inventory costs. These are the costs a company incurs to keep the components in its warehouse and then deliver them to the production floor. In simple terms, half as many parts means half as many transactions. Warehousing staff also have one less part to receive into stores and one fewer part to locate and move.
• A mask with less parts also provides further cost savings by reducing the amount of time it takes to assemble the finished product and/or the number of assembly steps. Overmoulding also eliminates secondary operations such as machining and use of adhesives.
5.15.2 Quality Improvement
• Improving quality leads to further cost savings. For example, the cost of rework which includes the cost of any materials scrapped, plus the cost of employing a worker to repair or replace a component may be avoided.
• An automated overmoulding operation would reduce assembly errors since fewer manual assembly steps are required.
• Quality derived through use of overmoulding also reduces costs in terms of reducing disgruntled customers. For example, the often difficult step of assembling a cushion to a frame utilizing a cushion-to-frame clip is avoided.
5.15.3 Sealing
• Since flexible materials seal better than harder materials, the use of flexible materials to surface harder materials will allow better seals to be formed. For example, improved sealing between the elbow and frame, and frame and cushion can be achieved.
5.15.4 Soft-Touch
• A soft to touch surface generally feels nicer and less clinical than a hard surface to a patient. Varying both the co-mould thickness and hardness can produce a range of different feels.
5.15.5 Biological Contamination can be Removed by Washing
• Mask components that have been co-moulded according to some embodiments of the invention can have biological contamination removed therefrom by washing the mask. The reason for this is that the components are integrally joined and thus the mask does not include any crevices that cannot be cleaned within the normal course of washing.
5.16 Materials
• Thermoplastic elastomers (TPEs), solid silicone rubbers and Liquid Silicone Rubbers (LSRs) are usually suitable materials for a flexible co-mould. It has been found by the inventors that a thermoplastic elastomer with the following general properties may be particularly advantageous:
• • Hardness of approximately 40 ShoreA
  • High Tear strength
  • Resistance to cleaning chemicals (e.g. soap, detergents etc.)
  • Low compression set
  • Ability to withstand cleaning temperatures of 93 degrees Celsius
  • Low friction and low squeak
  • Biocompatibility (specifically—ISO 10993, parts 3, 5, 6, 10 &11)
  • Good bonding to substantially rigid component
  • Good process control for high volume manufacture
  • Translucency
  • Low cycle time
• The following materials have been found to exhibit some or all of the above properties:
• • “Dynaflex® TPE Compounds” and “Versalloy®” made by GLS
  • “Santoprene™ Thermoplastic Vulcanizate” and “Santoprene™ Thermoplastic Vulcanizate” made by Advanced Elastomer Systems.
  • Silastic™ Silicone rubbers made by Dow Corning.
  • Elastosil™ Silicone rubbers made by Wacker.
• Where solid silicone rubbers are used, resin transfer moulding techniques may be used for moulding of the flexible components.
• Polycarbonate, polypropylene, trogamid (nylon) and pocan plastics are all suitable substantially rigid materials.
5.17 Other Variations
• While the invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. For example, any functionally suitable materials may be utilized in conjunction with this invention. Furthermore, the flexible and substantially rigid materials could have the same level of flexibility or resilience. In another embodiment, the substantially rigid material could be more flexible than the flexible material.
• Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments, or additional embodiments can reside in a single element or portion thereof of any given embodiment.
• In addition, while the invention has particular application to patients who suffer from OSA, it is to be appreciated that patients who suffer from other illnesses (e.g., congestive heart failure, diabetes, morbid obesity, stroke, bariatric surgery, etc.) can derive benefit from the above teachings. Moreover, the above teachings have applicability with patients and non-patients alike in non-medical applications.

Claims (21)

1.-20. (canceled)

21. A tub configured to receive a volume of liquid for a humidifier, the tub comprising:

at least one substantially rigid component including at least a first portion and a second portion, wherein the at least one substantially rigid component at least partially enclosing the volume of liquid in use, and wherein at least one of the first portion and the second portion has an increased affinity to adhesive bonding;

an elastomeric seal made from a more flexible material than the at least one substantially rigid component;

wherein the elastomeric seal is bonded directly to the at least one of the first portion and the second portion with the increased affinity to adhesive bonding.

22. The tub ofclaim 21, wherein the at least one substantially rigid component is constructed from plastic.

23. The tub ofclaim 21, wherein the at least one of the first portion and the second portion includes a plasma treated section or a corona treated section.

24. The tub ofclaim 21, wherein the elastomeric seal is formed from a liquid silicone rubber.

25. The tub ofclaim 21, wherein the at least one substantially rigid component includes a curved surface.

26. The tub ofclaim 25, wherein the at least one substantially rigid component includes a concave shape relative to a space for receiving said volume of liquid.

27. The tub ofclaim 21, wherein the elastomeric seal forms at least one channel with two side walls, in which at least a section of the at least one substantially rigid component is arranged.

28. The tub ofclaim 21, wherein the at least one substantially rigid component is a lid and the elastomeric seal is a lid seal.

29. The tub ofclaim 21, wherein the first portion includes a higher affinity to adhesive bonding as compared to the second portion, and wherein the elastomeric seal is only bonded to at least a part of the first portion.

30. A method of making the tub ofclaim 29, wherein at least a portion of the substantially rigid component that is intended to remain uncoated with the elastomeric seal is covered before the application of the elastomeric seal.

31. The tub ofclaim 21, wherein the at least one substantially rigid component and the elastomeric seal are injection molded.

32. The tub ofclaim 21, wherein an inner perimeter of the elastomeric seal is curved.

33. The tub ofclaim 21, further comprising a bottom wall and one or more side walls surrounding the bottom wall.

34. The tub ofclaim 21, wherein the at least one of the first portion and the second portion of the at least one substantially rigid component includes the increased affinity for adhesive bonding on a surface facing a space for receiving said volume of liquid.

35. The tub ofclaim 21, wherein the at least one substantially rigid component is a lid and the elastomeric seal is a lid seal.

36. The tub ofclaim 21, wherein the at least one substantially rigid component includes an opening, and wherein the elastomeric seal is connected to the at least one substantially rigid component around the opening.

37. An apparatus for treating a respiratory disorder in a patient, the apparatus comprising:

a patient interface;

a controllable motor-blower configured to generate a supply of air at a positive pressure relative to ambient pressure; and

the tub according toclaim 21; and

a heating element to heat liquid received within said tub.

38. A method for manufacturing the tub ofclaim 21, the method comprising:

providing the at least one substantially rigid component; and

attaching the at least one substantially rigid component in a fluid tight manner to the elastomeric seal, such that the at least one substantially rigid component forms at least part of a fluid tight space for receiving said volume of liquid,

wherein before the attaching of the at least one substantially rigid component and the elastomeric seal, treating at least one of the first portion and the second portion in order to increase the increased affinity to forming an adhesive bond.

39. The method ofclaim 38, wherein treating at least one of the first portion and the second portion involves applying a surface treatment, a plasma treatment, and/or a coronal treatment.

40. The method ofclaim 38, wherein the attaching of the at least one substantially rigid component and the elastomeric seal is done in an injection molding tool.

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