RESPIRATORY INTERFACE DEVICE AND METHOD OF MANUFACTURING A SEALING MEMBER FOR A RESPIRATORY INTERFACE DEVICE

Abstract

There is provided a method of manufacturing a sealing member for a respiratory interface device. The method comprises the steps of: (a) providing a mould having a cavity, a polymer injection port and a gas inlet port; (b) injecting a polymer through the polymer injection port into the cavity of the mould; and (c) introducing gas through the gas inlet port into the cavity of the mould, to form a sealing member of the respiratory interface device, thereby forming a sealing member of the respiratory interface device. The sealing member of the respiratory interface device comprises an internal chamber at least partially bounded by a resiliently deformable enclosing wall formed of the polymer, the enclosing wall including a patient-contacting surface, the patient-contacting surface having a form that is determined by the cavity of the mould and provides an anatomical fit with a patient.

Claims

1. A method of manufacturing a sealing member for a respiratory interface device, the method comprising the steps of: (a) providing a mould having a cavity, a polymer injection port and a gas inlet port; (b) injecting a polymer through the polymer injection port into the cavity of the mould; and (c) introducing gas through the gas inlet port into the cavity of the mould, to form a sealing member of the respiratory interface device, thereby forming a sealing member of the respiratory interface device, wherein the sealing member of the respiratory interface device comprises an internal chamber at least partially bounded by a resiliently deformable enclosing wall formed of the polymer, the enclosing wall including a patient-contacting surface, the patient-contacting surface having a form that is determined by the cavity of the mould and provides an anatomical fit with a patient.

2. The method as claimed in claim 1, wherein the patient-contacting surface has a leading portion, which is a portion that contacts a surface of the patient before any deformation of the sealing member, that is anatomically shaped at least in the direction of engagement of the sealing member with a surface of the patient, such that the position of the leading portion of the patient-contacting surface varies in this direction, at different positions along the patient-contacting surface.

3. The method as claimed in claim 2, wherein the leading portion and/or a central line on the leading portion of the patient-contacting surface has a varying position relative to a reference surface, which is a reference plane or a reference cylindrical surface, where the reference surface is arranged perpendicularly to the direction of engagement of the sealing member with the surface of the patient, or the direction of global pressure applied by the sealing member to the surface of the patient.

4. The method as claimed in claim 1, wherein the gas inlet port of the mould is connected to a source of gas, and the gas has a pressure that is sufficient to guide, deform and/or move the polymer to form the sealing member within the cavity of the mould.

5. The method as claimed in claim 1, wherein the gas inlet port of the mould projects into the cavity and has an exit opening into the cavity, through which the gas enters the cavity, the exit opening being separated from a surrounding interior surface of the mould that defines the cavity.

6. The method as claimed in claim 1, wherein the gas inlet port projects relative to a surrounding interior surface of the mould that defines the cavity, which causes an aperture to be formed in the enclosing wall of the sealing member, the aperture being in fluid communication with the internal chamber of the sealing member.

7. The method as claimed in claim 1, wherein polymer is injected through the polymer injection port into the cavity of the mould such that the cavity of the mould is only partially charged and wherein the polymer that is injected into the cavity of the mould has a volume that is less than the volume of the cavity such that, following injection of the polymer, but prior to introduction of gas, the polymer extends only partially along the cavity in the form of a unitary body, which is separated from the end of the cavity opposite to the end of the cavity at which the polymer injection port is disposed.

8. (canceled)

9. The method as claimed in claim 1, wherein the gas is introduced through the gas inlet port into the cavity of the mould when it is at least partially charged by the polymer.

10. The method as claimed in claim 1, wherein the internal chamber at least partially bounded by a resiliently deformable enclosing wall formed of the polymer is formed in the sealing member in the cavity of the mould.

11.-15. (canceled)

16. A sealing member for a respiratory interface device manufactured by the method as claimed in claim 1.

17. The sealing member as claimed in claim 16, wherein the sealing member comprises an internal chamber at least partially bounded by a resiliently deformable enclosing wall, the enclosing wall including a patient-contacting surface that has a form that provides an anatomical fit with a patient, wherein the sealing member includes an aperture in fluid communication with the internal chamber of the sealing member and with ambient air, such that ambient air may enter and exit the internal chamber during use.

18. The sealing member as claimed in claim 16, wherein the sealing member is for a respiratory mask, and the patient-contacting surface is generally aligned with the frontal plane of a patient, in use, but comprises convex surfaces at cheek regions of the patient-contacting surface, and/or concave surfaces at nose and/or chin regions of the patient-contacting surface, in a circumferential direction.

19.-20. (canceled)

21. The sealing member as claimed in claim 16, wherein the sealing member has one or more solid portions, without an internal chamber, such that the internal chamber has a first end and a second end, which are separated by one or more solid portions of the sealing member.

22. The sealing member as claimed in claim 21, wherein the one or more solid portions of the sealing member separating the first and second ends of the internal chamber consist of a single continuous solid portion.

23.-25. (canceled)

26. A method of manufacturing a respiratory interface device, the method comprising the steps of: (a) providing one or more moulds having a first cavity, a first polymer injection port, a second cavity, a second polymer injection port and a gas inlet port opening into the second cavity; (b) injecting a first polymer through the first polymer injection port into the first cavity of the mould to form a body portion of the respiratory interface device; (c) injecting a second polymer through the second polymer injection port into the second cavity of the one or more moulds, and introducing gas through the gas inlet port into the second cavity of the one or more moulds, to form a sealing member of the respiratory interface device, the sealing member of the respiratory interface device comprising an internal chamber at least partially bounded by a resiliently deformable enclosing wall formed of the second polymer, the enclosing wall including a patient-contacting surface, wherein the patient-contacting surface has a form that is determined by the second cavity of the one or more moulds and provides an anatomical fit with a patient; and wherein the body portion and the sealing member of the respiratory interface device may be formed in any order, such that either the body portion or the sealing member is an earlier-formed portion and the other of the body portion and the sealing member is a later-formed portion, and the later-formed portion is brought into engagement with the earlier-formed portion, during injection moulding of the later-formed portion, in a manner that fixes the body portion and the sealing member of the respiratory interface device together.

27.-28. (canceled)

29. The method as claimed in claim 26, wherein the one or more moulds may be arranged to enable the earlier-formed portion of the respiratory interface device to be disposed adjacent to or within the cavity (either the first or second cavity) for forming the later-formed portion of the respiratory interface device, such that the later-formed portion is brought into engagement with the earlier-formed portion, during injection moulding of the later-formed portion, in a manner that fixes the body portion and the sealing member of the respiratory interface device together.

30. (canceled)

31. The method as claimed in claim 26, wherein the one or more moulds comprises a mould having a first-shot configuration defining the first cavity and the first polymer injection port, and a second-shot configuration defining the second cavity, the second polymer injection port and the gas inlet port opening into the second cavity, such that in the first-shot configuration the first polymer is injected through the first polymer injection port into the first cavity of the mould to form the body portion of the respiratory interface device, and in the second-shot configuration the body portion of the respiratory interface device is disposed adjacent to the second cavity and the second polymer is injected through the second polymer injection port into the second cavity of the mould, and the gas is introduced through the gas inlet port into the second cavity of the mould, to form the sealing member of the respiratory interface device, and the sealing member is brought into engagement with the body portion, during injection moulding of the sealing portion, in a manner that fixes the body portion and the sealing member of the respiratory interface device together.

32. The method as claimed in claim 26, wherein the one or more moulds comprises a first mould having the first cavity and the first polymer injection port, and a second mould having the second cavity, the second polymer injection port and the gas inlet port opening into the second cavity, such that the first polymer is injected through the first polymer injection port into the first cavity of the first mould to form the body portion of the respiratory interface device, the body portion of the respiratory interface device is then transferred to the second mould, such that the body portion of the respiratory interface device is disposed within or adjacent to the second cavity, and the second polymer is injected through the second polymer injection port into the second cavity of the second mould, and the gas is introduced through the gas inlet port into the second cavity of the second mould, to form the sealing member of the respiratory interface device, and the sealing member is brought into engagement with the body portion, during injection moulding of the sealing portion, in a manner that fixes the body portion and the sealing member of the respiratory interface device together.

33.-36. (canceled)

37. The method as claimed in claim 34, wherein the gas inlet port projects relative to a surrounding interior surface of the mould that defines either the first or second cavity, which causes the aperture to be formed in either the body portion of the respiratory device, and/or the enclosing wall of the sealing member of the respiratory interface device.

38. The method as claimed in claim 34, wherein the gas inlet port project through the body portion of the respiratory mask into the second cavity.

39.-42. (canceled)

Description

[0131] FIG. 1 is a rear view of a mask body formed in a first shot of a two-shot moulding method according to a first embodiment of the invention;

[0132] FIG. 2 is a schematic representation of a first stage of a second shot of the two-shot moulding method according to the first embodiment of the invention, in which a polymer melt of the second shot is being introduced;

[0133] FIG. 3 is a schematic representation of a second stage of the second shot of the two-shot moulding method according to the first embodiment of the invention, in which the polymer melt of the second shot has been fully introduced;

[0134] FIG. 4 is a schematic representation of a third stage of the second shot of the two-shot moulding method according to the first embodiment of the invention, in which a gas is partially introduced into the polymer melt of the second shot;

[0135] FIG. 5 is a schematic representation of a fourth stage of the second shot of the two-shot moulding method according to the first embodiment of the invention, in which the gas is fully introduced into the polymer melt of the second shot;

[0136] FIG. 6 is a respiratory mask formed by the two-shot moulding method according to a first embodiment of the invention, in which the polymer and gas inlets for the second shot are shown;

[0137] FIG. 7 is a first perspective view of a respiratory mask formed by two-shot moulding method according to a second embodiment of the invention; and

[0138] FIG. 8 is a second perspective view of the respiratory mask formed by the two-shot moulding method according to the second embodiment of the invention.

[0139] The method according to a first embodiment of the invention illustrated in FIGS. 1-6 is a two-shot injection moulding method for manufacture of a respiratory mask.

[0140] The injection moulding process typically involves apparatus comprising injection units that each include an outlet nozzle, a tool that defines the mould, and a clamp unit. The clamp unit is arranged to move a component of the mould tool between a closed configuration, in which the polymer melt may be injected into the cavities of the mould, and an open configuration, in which the formed article may be removed from the mould tool.

[0141] The mould tool defines a mould that is provided with a first cavity and a second cavity, with each cavity having a polymer injection port for introducing a polymer melt into that cavity and each cavity being defined by interior walls of the mould.

[0142] A first injection unit for the first shot of the two-shot injection moulding method is provided with a first polymer melt which, in this embodiment, is polypropylene (PP), a thermoplastic. The first polymer melt is heated in the injection unit until it is soft enough to flow, and the outlet nozzle of the injection unit is moved into engagement, and fluid communication, with the injection port of the first cavity of the mould.

[0143] In addition, a second injection unit for the second shot of the two-shot injection moulding method is provided with a second polymer melt which, in this embodiment, is a thermoplastic elastomer (TPE), a thermoplastic. The second polymer melt is heated in the second injection unit until it is soft enough to flow, and the outlet nozzle of the second injection unit is moved into engagement, and fluid communication, with the injection port of the second cavity of the mould.

[0144] In the first shot of the method according to the first embodiment of the invention, the mould is moved to its first-shot configuration. The first injection unit then applies pressure to the first polymer melt, eg using a piston and cylinder arrangement (which may also be known in the field as a screw and barrel arrangement), and injects the first polymer melt through the outlet nozzle and through the polymer injection port into the first cavity of the mould. The polymer melt within the first cavity is then allowed to commence cooling, while the pressure applied to the polymer melt is maintained, until the polymer melt is partially solidified.

[0145] The polymer melt injected into the first cavity takes the form of a mask body 10. This mask body is shown in FIG. 1, with the mould not shown for clarity.

[0146] The mask body 10 comprises a peripheral edge 16, and a tapered wall 12 that extends forwardly and inwardly from the peripheral edge 16 to a tubular connector 14. The tubular connector 14 is a conventional male or female cylindrical connector, eg 22 mm diameter, for connection to a respiratory circuit. The tapered wall 12 is generally dome-shaped, with a mouth portion having a generally annular cross-section, in a plane that corresponds to the plane of a patent's face, in use, ie the frontal plane, and a narrowed nose portion that is generally triangular in shape, with a rounded apex for engagement with the bridge of the nose of the patient. In the mask body shown in FIG. 1, the nose portion of the tapered wall 12 also includes a narrowed portion along the longitudinal axis of the mask body, extending from the tubular connector 14 towards the rounded apex of the nose portion of the tapered wall 12. This narrowed portion of the tapered wall 12 defines side surfaces that may be gripped by a user, eg in a pinching action.

[0147] Once the mask body 10 has been formed, in a partially solidified state, in the first shot of the two-shot injection moulding method, the mould is then moved into the second-shot configuration, such that the second cavity of the mould is in fluid communication with the peripheral edge 16 of the mask body 10 and a border region of the surface of the mask body 10 adjacent to the peripheral edge 16.

[0148] In a second shot of the method according to the first embodiment of the invention, whilst the mask body 10 remains in a partially solidified state, the second injection unit applies pressure to the polymer melt, eg using a piston and cylinder arrangement, and injects the second polymer melt through the outlet nozzle and through the polymer injection port into the second cavity of the mould. A blowing agent may be mixed with the second polymer melt in the second injection unit, prior to the application of pressure and injection into the second cavity of the mould, which may ensure that the progression of injected gas through the cavity of the mould is more uniform. This method is further described in UK patent application number 2013108.2.

[0149] FIG. 2 shows the second polymer melt 20 partially introduced into the second cavity, and FIG. 3 shows the second polymer melt 20 fully introduced into the second cavity. The second polymer melt 20 only partially charges the second cavity, as shown in FIG. 3, and hence the volume of the second polymer melt 20 is less than the volume of the second cavity. Since the polymer injection port 28 for the second cavity is disposed at the apex of the nose portion of the mask body 10 (see FIG. 6), and the second cavity extends in both directions from the polymer injection port 28 around the peripheral edge 16 of the mask body 10, the second polymer melt 20 flows along the second cavity in two branches 21, 22 from the polymer injection port 28, and extends substantially the same distance into the second cavity in each branch 21, 22.

[0150] Once the second polymer melt 20 has been fully introduced into the second cavity, and partially charged the second cavity, nitrogen gas 30 is introduced into the second polymer melt 20 in the second cavity through a gas inlet port 38 (see FIG. 6). The gas inlet port 38 is situation adjacent to, and orientated perpendicularly to, the polymer injection port 28 for the second cavity. The gas inlet port 38 extends from a wall of the second cavity into a central region of the second cavity, such that the gas forms a bubble within the second polymer melt 20 in the second cavity.

[0151] Since the gas inlet port 38 is also disposed at the apex of the nose portion of the mask body 10, and the second cavity extends in both directions from the gas inlet port 38 around the peripheral edge 16 of the mask body 10, the bubble of gas 30 flows along a central axis of the second polymer melt 20 in the second cavity in two branches 31, 32 from the gas inlet port 38.

[0152] FIG. 4 shows the gas 30 partially introduced into the second polymer melt 20 of the second cavity, and FIG. 5 shows the gas fully introduced into the second polymer melt 20 of the second cavity.

[0153] As shown in FIGS. 4 and 5, the introduction of gas 30 moves the second polymer melt 20 further along the second cavity, towards the chin region of the mask body 10, until the two branches 21, 22 of the second polymer melt 20 meet, mix and join in the chin region of the mask body 10. In this embodiment, the gas 30 introduced into the second polymer melt 20 in the second cavity is sufficient to form a thin-walled sealing cushion 42 from the second polymer melt 20, with a gas-charged internal chamber 44. However, the gas 30 introduced into the second polymer melt 20 in the second cavity remains in two branches 31, 32, and does not meet at the chin region of the mask body 10. Instead, the two branches 31, 32 of the gas-charged internal chamber 44 each terminate with a tapered end portion, with each tapered end portion being disposed to each side of a solid portion of the second polymer melt, ie a portion of the second polymer melt that does not contain a gas-charged interior, that forms a chin region 46 of the sealing cushion 42.

[0154] Once the sealing cushion 42 of the respiratory mask has been formed, the mask body 10 and the sealing cushion 42 are allowed to cool and completely solidify, whilst the pressure applied to the polymer melt by the gas 30 is maintained. This bonds the second polymer to the border region and the peripheral edge of the mask body 10, such that the mask body 10 and the sealing cushion 42 of the respiratory mask are bonded together. There is therefore no need for additional assembly steps, such as gluing, to fix the mask body 10 and the sealing cushion 42 together.

[0155] The second cavity of the mould is shaped to provide the sealing cushion 42 of the respiratory mask with an anatomical shape, which is configured to correspond to the contours of a patient's face about their nose and mouth.

[0156] The sealing cushion 42 of the respiratory mask comprises a thin enclosing wall surrounding a gas-charged internal chamber 44. Furthermore, since the gas inlet port 38 extends from a wall of the second cavity into a central region of the second cavity, the wall of the sealing cushion 42 of the respiratory mask forms around the gas inlet port 38, which provides an aperture in the wall of the sealing cushion 42 of the respiratory mask when the respiratory mask is removed from the mould. This aperture in the wall of the sealing cushion 42 of the respiratory mask provides fluid communication between the gas-charged internal chamber 44 of the sealing cushion 42 of the respiratory mask and ambient air.

[0157] FIGS. 7 and 8 show a respiratory mask 100 that has been formed by a two-shot moulding method according to a second embodiment of the invention. This respiratory mask 100 is identical to those respiratory masks formed by the first embodiment of the method according to the invention, as described above, save for the location of the aperture 138 formed by the gas inlet port 38.

[0158] In the respiratory mask 100 formed by the second embodiment of the method according to the invention, the aperture 138 formed by the gas inlet port is located in the mask body 112 and an underling wall of the sealing cushion 142, rather than in the deformable wall of sealing cushion 142 that extends from the mask body 112. This location of the aperture 138 is achieved by providing a mould in which the gas inlet port 38 extends from a wall of the first cavity of the mould and into a central region of the second cavity, in a second-shot configuration of the mould. In this arrangement, when the first polymer is injected into the first cavity of the mould to form the mask body 112 the mask body 112 forms around the gas inlet port 38. In a second-shot configuration of the mould, the gas inlet port 38 extends through the mask body 112 in the first cavity and projects into the second cavity. In this arrangement, when the second polymer is injected into the second cavity of the mould to form the sealing cushion 142, a wall of the sealing cushion 142 that underlies an adjacent wall of the mask body 112 forms around the gas inlet port 38. An aperture 138 is therefore formed in the mask body 112, and the underlying wall of the sealing cushion 142, of the respiratory mask 100 when the respiratory mask 100 is removed from the mould. This aperture 138 provides fluid communication between the gas-charged internal chamber of the sealing cushion 42 of the respiratory mask 100 and ambient air.

[0159] In a third embodiment of a method according to the invention, an overmoulding process is used. This differs from the first and second embodiments, which are two-shot moulding processes, in that the mask body formed of the first polymer (the substrate) is transferred to a second cavity in a second mould, typically once substantially or completely solidified, before the second polymer is injection moulded into the second cavity, and hence “overmoulds” the mask body. In this embodiment, the sealing member formed by the second polymer is fixed to the mask body formed by the first polymer by one or more of a chemical bond and a mechanical bond.

[0160] Furthermore, any of the first, second and third embodiments may also be used with a thermosetting polymer, eg for the sealing member. For example, liquid silicone rubber (LSR) may be the second polymer for forming the sealing member. However, where a thermosetting polymer is used, the injection moulding step and the associated apparatus will differ to these described above, as thermosetting polymers typically require heat to initiate curing in order to harden. For liquid silicone rubber, a liquid injection moulding (LIM) process is typically used.

[0161] The materials commonly used in the LIM process are silicones and acrylics. Utilising a pump, the LIM process brings together a base-forming plastic, which can be strengthened with additives and fibres, and a catalyst. Each will be pumped in a 1:1 ratio into a static mixer, which triggers the mixing reaction, to form liquid silicone rubber (LSR), for example. The outlet nozzle of the injection unit is moved into engagement, and fluid communication, with the injection port of the cavity of the mould.

[0162] The liquid mixture is then injected into the cavity of the mould. The injection of gas and the forming of the sealing member would be the same as that described above for thermoplastics. However, the polymer is not allowed to cool and solidify. Instead, the mould is heated, eg at temperatures from 180 to 200° C., in order to initiate curing. Once the polymer has cured, the respiratory interface device may be removed from the mould.