Classifications

• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
  • G10K9/18—Details, e.g. bulbs, pumps, pistons, switches or casings
  • G10K9/22—Mountings; Casings
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
  • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
  • G10K9/122—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated using piezoelectric driving means

Definitions

• the invention relates to an acoustic signal generator, in which electrical vibrations in a membrane composed of a carrier disk and a piezo element produce mechanical vibrations which produce sound waves, the membrane being supported with its edge part in a holder which is held in a the membrane receiving and provided with a cover housing is provided.
• Acoustic signal and sound transmitters are known in various designs.
• electrical vibrations are converted into analog acoustic vibrations, the electrical vibrations first producing mechanical vibrations in a vibratable device, which in turn generates sound waves in the air which can be perceived by the human ear if they are in the frequency range (16 Hz to 20 * 000 Hz) detectable by the human ear.
• the piezo sounder is known as a further signal transmitter, which has been used as a warning and signal transmitter in many areas of technology and is used instead of optical signal transmitter. It is characterized by a relatively small current consumption and can therefore where optical signal transmitters had to be used because of the high current consumption of mechanical vibrators, can be used with advantage.
• the piezo sound transducer essentially consists of a membrane clamped at the edge, which consists of an electrically conductive metallic disk, on which a disk-shaped piezo element is attached on one side.
• the piezo element consists of piezoceramic material with a material thickness of a few tenths of a millimeter.
• the membrane is covered on the front side of the housing by an insulation layer which is clamped in the housing and protects the piezo element against wetting by water.
• the membrane is in this case on one, as vorzugs ⁇ a knife-edge bearing forming contact ring supported and the housing end face is sealed by 'an elastic Dichtungs ⁇ ring, which is for pressing the membrane on the contact ring at a predetermined bias voltage. This ensures that the sound power is not impaired and that a long lifespan is achieved.
• FIG. 1 shows a longitudinal section of an acoustic signal transmitter in a flood-protected design
• Fig. 2 is a partial section of the acoustic signal generator according to Fig. 1 and
• FIG. 3 shows a detail of the sealing of the membrane of the tical signal generator according to Fig. 1st
• the acoustic sounder shown in FIG. 1 has a cylindrical housing 1, which is closed at one end 2 by a housing base 3. At the other end 4, the housing is closed by a cap-shaped cover 5, which is composed of a cover part 6 and a ring part 7.
• the ring part 7 has an internal thread 8 on the inner circumference, with which the cover 5 is screwed onto an external thread 9 arranged on the outer circumference of the housing 1.
• the lid part 6 there are also a plurality of openings 10 which are expediently arranged on the edge of the lid part 6 so that moisture or water which has penetrated in the horizontal sensor axis 11 can be measured again.
• a retaining ring 15 is screwed onto the central part 12 of the housing 1, with which the housing 1 is mounted in a plate, e.g. a control panel, can be clamped, with a support ring 16 under one. Shoulder 17 of the housing 1 is placed and the housing 1 is additionally held in the plate 13 by fixing screws 18 arranged in the retaining ring 15.
• the electrical leads 19, 20 are inserted in the housing base 3 and extend up to a printed circuit board 25 for supplying a control which is arranged on the printed circuit board 25.
• the acoustic sound generator is described with reference to FIG. 2, which shows the upper part of FIG. 1 in an enlarged view.
• the same reference numerals as in FIG. 1 denote the same parts.
• the active part of the sound generator is a membrane 30, which is designed as a laminated body, see FIG. 3.
• the membrane 30 has an insulating carrier disk 31 directed against the outside air and made of a plastic, for example of an epoxy resin, on which housing - A metal layer 32, for example a copper layer, is applied, for example vapor-deposited, on the base side.
• a disk-shaped piezo element 33 is fastened on the metal layer 32.
• the carrier disk 31 can be connected loosely or also firmly to the remaining parts of the membrane 30.
• the membrane 30 is supported on a metal contact ring 34, for example made of brass, the contact ring forming a cutting edge bearing 35 on which the metal layer 32 is supported.
• a metal contact ring 34 for example made of brass
• the contact ring forming a cutting edge bearing 35 on which the metal layer 32 is supported.
• one side of the piezo element 33 is connected to one of the feed lines 19, 20.
• the contact ring 34 is supported on the edge of the printed circuit board 25, which is also supported on the inner webs 38 of the bearing webs 38.
• an elastic sealing ring 39 for example an O-ring, which on the side facing away from the membrane 30 carries a pressure ring 40 which has a collar 41 with which the O-ring is partially encompassed .
• a protective collar 42 which forms the other end 4 of the housing 1.
• a predetermined pressure is exerted on the mounted sound generator by the pressure ring 40. Since the sealing ring 39 is partially surrounded on the inside by the collar 41, the sealing ring 39 presses against the protective collar 42 on the one hand and against the carrier disk 31 of the membrane 30 on the other hand. This forms two sealing points 43, 44 which cover the metal layer 32 and the piezo Seal element 33 reliably against the interior 45 connected to the outside air. It is expedient here that the resulting compressive force at the sealing point 43 is perpendicular to the cutting edge bearing 35 formed by the contact ring 34.
• the pressure ring 40 can only be compressed by the cover 5 until a shoulder 6 arranged on the inside of the ring part 7 rests on the end face of the protective collar 42. This type of sealing of the metal layer 32 and the piezo element 33 can ensure that the oscillation behavior of the membrane 30 is not adversely affected.
• a further interior space 47 is formed between the membrane 30 and the printed circuit board 25.
• the two interior spaces 45, 47 also influence the vibration behavior of the membrane 30.
• An increase in the volume can be achieved in that, in addition to the openings 10 to the interior 45 in the circuit board 25, further openings 48 are provided which form a connection to a closed space 49 in the interior of the housing 1. It is essential in the acoustic signal transmitter described that the carrier disk 31 of the membrane 30, which at the same time forms an insulation layer, and the sealing ring 39 completely seal the piezo element 33 and the further interior 47 from the environment .
• the housing 1 is expediently made of plastic.
• the cover 5 can be made of both plastic and metal, for example aluminum.
• the pressure ring 40 is made of plastic. This makes the formation of an electrical creeping path considerably more difficult if liquid penetrates into the inner space 45, since the sealing ring 39 is then also insulated on the side facing away from the membrane 30.
• the acoustic signal generator described is considerably smaller than that shown in FIGS. 1-3.
• the cover 5 has a diameter that can be 30 mm and less.
• the same formwork performance i.e. up to about 85 - 95 dB can be achieved.
• protection against touching the piezo element 33 and other harmful influences is also achieved.

Landscapes

• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Multimedia (AREA)
• Piezo-Electric Transducers For Audible Bands (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=4274360

Family Applications (1)

Country Status (2)

Cited By (5)

Families Citing this family (2)

Citations (5)

• 1986
  • 1986-11-03 CH CH434586A patent/CH672386A5/de not_active IP Right Cessation
• 1987
  • 1987-10-01 WO PCT/CH1987/000132 patent/WO1988003691A1/de unknown

Patent Citations (5)

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