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EP-3574960-B1 - SPEECH DIAPHRAGM MODULE FOR A RESPIRATOR MASK

EP3574960B1EP 3574960 B1EP3574960 B1EP 3574960B1EP-3574960-B1

Inventors

  • FERRY, Christopher Andrew

Dates

Publication Date
20260506
Application Date
20190425

Claims (14)

  1. A speech diaphragm module (200) comprising: a body (202); a lid (206) secured to the body at a solid state weld joint to form an enclosed volume therein; a resilient film (210) secured to the body within the enclosed volume along an attachment join formed around a periphery of the resilient film, the attachment join being a solid state weld joint between the resilient film and the body and being separate from the solid state weld joint between the lid and body; and a tensioning feature (226) attached to the lid (206) and arranged to displace an operative portion of the resilient film relative to the attachment join to apply a tension across the resilient film.
  2. A speech diaphragm module according to claim 1, wherein the tensioning feature is a protruding rib on an underside of the lid, the protruding rib being configured to engage the resilient film when the lid is secured to the body.
  3. A speech diaphragm module according to claim 2, wherein the enclosed volume is cylindrical, and wherein the protruding rib is a circle whose centre lies on an axis of the cylindrical volume.
  4. A speech diaphragm module according to claim 3, wherein the protruding rib lies radially inwardly of the attachment join.
  5. A speech diaphragm module according to any preceding claim, wherein the body and lid form a cylindrical housing.
  6. A speech diaphragm module according to any preceding claim, wherein the body comprises a cup-shaped portion, and wherein the lid is secured to the body to cover the cup-shaped portion to form the enclosed volume.
  7. A speech diaphragm module according to any preceding claim, wherein the solid state weld joint between the lid and body is formed outwardly from the attachment join.
  8. A speech diaphragm module according to any preceding claim, wherein the lid has a plurality of holes (208) formed therethrough.
  9. A speech diaphragm module according to any preceding claim, wherein the body comprises a supporting wall (212) that spans across a bottom face of the enclosed volume.
  10. A speech diaphragm module according to claim 9, wherein the supporting wall has a plurality of holes (214) formed therethrough.
  11. A method of manufacturing a speech diaphragm module (200), the method comprising: mounting a resilient film (210) over an opening into a cup-shaped portion of a body (202) for the speech diaphragm module; followed by welding the resilient film to the body at an attachment join around a periphery of the resilient film; followed by mounting a lid (206) over a top surface of the body to enclose a volume containing the resilient film; followed by welding the lid to the body at a weld joint around a periphery of the lid, the weld joint being separate from the attachment join; and displacing, by a tensioning feature (226) located within the enclosed volume and attached to the lid (206), an operative portion of the resilient film relative to the attachment join.
  12. A method according to claim 11, wherein at least one of the following applies: (a) the tensioning feature is a protruding rib on an underside of the lid, whereby the operative portion of the resilient film is displaced upon mounting the lid over the top surface of the body; (b) the welding is ultrasonic torsional welding.
  13. A method according to claim 11 or 12, wherein the weld joint is formed outwardly of the attachment join.
  14. A respirator (100) having a speech diaphragm module according to any one of claims 1 to 10.

Description

FIELD OF THE INVENTION The invention relates to respirator masks, and in particular to speech diaphragm modules to facilitate transmission of a user's speech when wearing a respirator mask. BACKGROUND TO THE INVENTION It is known to provide respirator masks with means for assisting transmission of speech to aid close communication. Typically a respirator mask is provided with a speech diaphragm, i.e. a resilient membrane, that is vibratable by the sound waves associated with speech. The speech diaphragm may operate passively, i.e. may simply be a means for permitting or facilitating transmission of sound waves from an inner (sealed) volume to the surrounding environment. Such conventional passive devices can be relatively inefficient in sound transmission. It is therefore known to provide additional active assistance for speech transmission, e.g. in the form of microphones or other electroacoustic transducer systems which are arranged to amplify speech. Whilst such systems can be effective in improving speech transmission, they require additional components and manufacturing complexity. It is therefore desirable to provide a respirator mask with a more effective passive speech diaphragm module. JP2000189529 discloses a voice transmitter with a thin voice transmitting film between a front surface frame member and a rear surface frame member. US6305370B1 discloses a voice transmitter for a breathing protective mask. The voice transmitter includes a membrane housing and a clamping ring which can be connected to the membrane housing. The voice transmitter also includes a voice membrane between the membrane housing and the clamping ring. The voice membrane has an outer membrane portion which is accommodated at a connecting location between the clamping ring and the membrane housing. An inner portion of the membrane is tensioned over an annularly-shaped projection located on the membrane housing. The pretensioning of the voice membrane is adjusted in a simple manner in that the clamping ring has an annularly-shaped support surface for the inner membrane portion and that the connecting location is configured as a threaded connection. JP2002219185A discloses that a voice transmission device is structured of a case body and a cover with a voice transmission film being put in. A synthetic resin is used as its main component member, maintaining the airtightness for the voice transmission main body. SUMMARY OF THE INVENTION At its most general, the present invention is defined by the appended independent claims while the advantageous embodiments are defined by the dependent claims. A disclosed passive speech diaphragm module is one in which a tensioning force is applied to a resilient film that forms the diaphragm independently of the means by which the film is secured within the module. The speech diaphragm module is formed by sandwiching the film between two mating components, which the tensioning force is applied by the geometry of the components when mated. The components are secured together by solid state welding, thereby obviating the need for additional attachment or sealing elements. The invention may thus provide a speech diaphragm module capable of cost-effective manufacture and assembly with a more effective passive speech transmission function. According to the invention, there is provided a speech diaphragm module comprising: a body; a lid secured to the body to form an enclosed volume therein; a resilient film secured within the enclosed volume along an attachment join formed around a periphery of the resilient film, the attachment join being a solid state weld joint between the resilient film and the body; and a tensioning feature arranged to displace an operative portion of the resilient film relative to the attachment join to apply a tension across the resilient film. The tensioning feature may be arranged to operate independently of the attachment join. In other words, the tension across the operative portion of the resilient film (which may form a vibratable diaphragm in use) is primarily or solely created by displacement of the resilient film away from a position that it would naturally adopt once secured within the enclosed volume. This arrangement may facilitate manufacture and may mean the operative portion exhibit improved speech transmission performance. The resilient film is attached to the body at the attachment join. The tensioning feature is provided on the lid. Thus, when the lid is mounted over the body, the tensioning feature is brought into engagement with the resilient film. For example, the tensioning feature may be a protruding rib on an underside of the lid, the protruding rib being configured to engage the resilient film when the lid is secured to the body. The resilient film is secured to the body at the attachment join. The film and body form a sub-assembly to which the lid is attached. The enclosed volume may be cylindrical. The protruding rib may be a circle whose centre lies