WO1996027863A1 - Dispositif de production de sons - Google Patents

Dispositif de production de sons Download PDF

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Publication number
WO1996027863A1
WO1996027863A1 PCT/SE1995/001113 SE9501113W WO9627863A1 WO 1996027863 A1 WO1996027863 A1 WO 1996027863A1 SE 9501113 W SE9501113 W SE 9501113W WO 9627863 A1 WO9627863 A1 WO 9627863A1
Authority
WO
WIPO (PCT)
Prior art keywords
surface element
arrangement
sound
shell
elements
Prior art date
Application number
PCT/SE1995/001113
Other languages
English (en)
Inventor
Lars Ståhl
Original Assignee
Staahl Lars
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from SE9500833A external-priority patent/SE9500833D0/xx
Priority claimed from SE9501174A external-priority patent/SE9501174D0/xx
Application filed by Staahl Lars filed Critical Staahl Lars
Priority to AU39413/95A priority Critical patent/AU3941395A/en
Publication of WO1996027863A1 publication Critical patent/WO1996027863A1/fr

Links

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
    • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
    • G10K9/121—Flextensional transducers
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B15/00—Identifying, scaring or incapacitating burglars, thieves or intruders, e.g. by explosives

Definitions

  • the present invention relates to a device for generating power ⁇ ful acoustic pressure in air so as to prevent trespass or pres ⁇ ence in an area outdoors or indoors, in a building, in a vehicle or the like so as to deliver a warning signal calling for attention as a siren or fade-out sound.
  • the generation of unpleasant sound is also comprised herein.
  • the object of the present invention is to provide a device which to a large extent reduces the disadvantages mentioned above of the already known devices of the type defined in the intro ⁇ duction.
  • This object is according to the invention obtained by providing a device according to the appended claim 1.
  • a device according to the appended claim 1 By adapting the flextensional technique and utilise it within this totally new field of use possibilities to design devices for generating very high acoustic pressures in air and/or delivering sound having a very stressful influence are provided. It has turned out to be possible to obtain in this context very advantageous resonance effects by utilising the flextensional technique for generating sound in air.
  • Devices already known of the flextensional type are de ⁇ signed to be used in water and have a low transmission ratio of the movement of the driving unit through the constitution thereof.
  • the sur ⁇ face element of the arrangement has a low mass/surface unit in the mid region between said ends and a mass and stiffness in ⁇ creased at the end. Thanks to this design of said surface ele- ment it is possible to utilise a high transmission ratio (is defined further on) and by that obtain a high acoustic pressure at high frequencies without any collapsing of the surface element, i.e. the base oscillation mode will be maintained into comparatively high frequencies, which is particularly advantageous when utilising the device as siren.
  • light flextensional shells adapted to air may give high resonance effects and be designed with high transmission ratios of the movement of the driving unit without collapsing or rippling at high frequencies, which may give very high acoustic pressures in air, and particularly for certain resonance frequencies, and the device is therefore particularly suited as siren where high acoustic pressure for individual high frequen ⁇ cies is desired.
  • the device also becomes lighter than the prior art with a con ⁇ siderably weight reduction for corresponding acoustic pres ⁇ sures. This means that they are particularly suitable for mobile use.
  • the sound generator may be designed with a considerably higher efficiency than sound generators known for air.
  • the flextensional technique previously used for generating sound in water may therefor with success be utilised in air for these ap ⁇ plications.
  • said surface element has a high stiffness with respect to the av ⁇ erage density thereof by incorporating material portions therein having a lower density than the material constituting the rest of the surface element or by arranging cavities therein. It is by this possible to obtain a light but nevertheless stiff surface element, which means that the surface element may be given a high transmission ratio and by that deliver a high acoustic power per surface unit.
  • the device comprises a plurality of said arrangements, and at least some of these arrangements are designed to enter into reso ⁇ nance at different frequencies.
  • a device is able to gener ⁇ ate sound at different frequencies having very powerful and varying acoustic pressure, so that such a device may emit a very unpleasant sound having a highly stressful influence, and it is by that excellent for preventing trespassing and/or staying within an area and in this way give a maximum distance action.
  • a further advantage in preventing trespassing is that the inven ⁇ tion has several powerful resonances and may accordingly also individually for a singular sweeping sound with a constant am ⁇ plitude give a very varying sound impression.
  • said arrangement has the surface element coupled to pipe, tube or horn, which makes it possible to obtain a directed sound having an elevated acoustic pressure as well as utilise also resonances at said pipe, tube or horn has.
  • the device is then particularly suited for being used as driving unit in horns, since it is possible to utilise the high transmission ratio and have a large available power that at the same may move a large air mass.
  • the definition "coupled” comprises direct as well as indi ⁇ rect coupling.
  • the flextensional technique is suitably combined with horn.
  • the device comprises a plurality of pipes, tubes or horns having different resonance frequencies coupled to said surface element, which enables further variations of the sound gener ⁇ ated by the device for producing a powerful signal with a stressful impression.
  • the device comprises a control unit arranged to control said arrangements to very short periods of time between the occurrence of different resonance frequencies which gives a very strongly stressful sound impression.
  • the device comprises at least one element arranged to delimit an air volume together with at least one surface element of the arrangement.
  • the air flow from the surface element is in this way stopped, which in this way has turned out to give an in ⁇ creased resonance effect and enables modulation of the reso ⁇ nance frequency for light membranes, so that the device is able to create a powerful acoustic pressure and by that is suitable especially as siren.
  • said surface element forms a shell-like construction, and at least one said element is ar ⁇ ranged inside the shell, which constitutes a preferred possibility to delimit said air volume.
  • the shell has at least an opening extending in the longitudinal direction of the surface element and the said element is placed outside the shell sub ⁇ stantially covering this opening.
  • the element has holes, which also has turned out to result in an increased resonance effect.
  • pipe or horn is according to the invention con ⁇ nected to said holes, which also has turned out to give an in ⁇ creased resonance effect and increased acoustic pressure.
  • the device comprises an outer casing for protecting said ar ⁇ rangement, which is important since possibly particles on a light surface element would bring it out of balance, which reduces the acoustic pressure thereof.
  • a casing may be used as reflector, since it is desired to normally direct the sound horizontally as siren.
  • the arrangement is en ⁇ closed in a horn forming said casing.
  • Fig. 1 is a simplified section view illustrating a device for generating sound while utilising the so called flexten- sional technique
  • Fig. 2 is a simplified section view of a homogenous surface element with stiffness reduction at the ends for in ⁇ creased transmission ratio
  • Fig. 3 is a simplified section view of a homogenous surface element with an increased mass and stiffness at the ends
  • Fig. 4 is a section view of a surface element having an in ⁇ termediate portion with a lower density than the mate ⁇ rial portions outside thereof
  • Fig. 5 is a section view illustrating a surface element having an intermediate material portion with a lower density than material portions located outside thereof, as well as a substantial stiffness reduction at the ends for in ⁇ creased transmission ratio,
  • Fig. 6 is a front view illustrating a surface element which ac ⁇ cordingly is intended to oscillate in the plane of the paper, no endbeams being shown and the surface element having holes provided with an air-permeable material having a lower density than the rest of the surface element,
  • Fig. 7 is a view corresponding to Fig. 6, illustrating a surface element having a width decreasing towards the mid region
  • Fig. 8 is a view corresponding to Fig. 6 of a surface element with a construction having slots, in which the light surface has been achieved by a plurality of light sur- faces, for instance by drilling a homogenous material out for obtaining a thinner surface or drilling through and covering the holes for instance by a thin film, with two surrounding stiff surfaces,
  • Fig. 9 is a view corresponding to Fig. 6 of a surface element having a construction with slots and an intermediate light surface and two surrounding stiffer surfaces,
  • Fig. 10 is a view corresponding to Fig. 6 of a surface element having a construction with slots and inclined surfaces
  • Fig. 11 is a view corresponding to Fig. 6 of a surface element having a construction with slots, in which the stiffer surface is less wide at the middle thereof for reducing the load on the ends, and the lighter surface is wider at the middle thereof,
  • Fig. 12 is a schematic section view, illustrating a device ac ⁇ cording to a preferred embodiment of the invention having two surface elements in one and the same ar ⁇ rangement, which are arranged to emit or radiate through one pipe each,
  • Fig. 13 is a schematic section view illustrating how surface elements in a device according to the invention may be placed in a casing/a pipe for directing the sound generated
  • Fig. 14 is a schematic section view of a device according to a preferred embodiment of the invention, in which an ar ⁇ rangement having two surface elements is placed in a linearly rising horn,
  • Fig. 15 is a simplified section view illustrating how a sound generating arrangement may be placed in a tube
  • Fig. 16 is a simplified section view illustrating a device having an outer casing with inclined sides placed towards the surface element, which protect the surface element, function as reflectors and delimit the volume on stacking,
  • Fig. 17 is a simplified section view illustrating a device having plates on each side of the unit
  • Fig. 18 is a simplified section view illustrating an example of how a surface element may be placed in a volume to which a horn is coupled
  • Fig. 19 is a simplified section view illustrating a device in which elements are placed behind the respective sur ⁇ face element so as to by that delimit an air volume
  • Fig. 20 is a view of a device in which elements delimiting an air volume are placed outside the shell construction formed by the surface elements,
  • Fig. 21 shows corresponding elements as Fig. 20 with ele ⁇ ments placed inside the shell construction and sub- stantially covering the openings thereof, and
  • Fig. 22 is a section view corresponding to Fig. 21 with a plu ⁇ rality of elements arranged in succession inside the shell.
  • An arrangement generating sound according to this technique has a driving unit 1 only indicated by force ar ⁇ rows 1 , which usually is constructed by an inner driving rod of a magnetostriction material, around which a coil is winded and the opposite ends of which are limited by permanent magnets.
  • a driving unit 1 usually is constructed by an inner driving rod of a magnetostriction material, around which a coil is winded and the opposite ends of which are limited by permanent magnets.
  • the magnetic flux in the driving rod is varied, resulting in a length alteration of the latter being obtained.
  • the permanent magnets pre-magnetise the driving rod with a stationary, permanent magnetic flux an ex- panding as well as constricting motion of the driving rod may be obtained.
  • the driving unit 1 is arranged inside a shell formed by two surface elements 2 having the longitudinal axis thereof co ⁇ inciding with the major axis of the bent shell.
  • the driving unit is constricted in the shell between pieces 3 placed in the two ends 4, 5 thereof, so called endbeams.
  • endbeams During lengthening and shortening of the driving unit the end beams 3 and by that the two opposite ends of the surface elements will be influenced away from each other and towards each other, respectively, while describing an oscillation motion in the direction of the major axis of the bent shell. This motion will be transferred into an oscillational motion of the surface elements transversally thereto in the direction of the double arrows 6 and 7.
  • the invention also comprises an embodiment not shown, in which prolongators, which have to be solid, preferably of steel, are put in between the inner driving unit and the end beams in the case a not too long driving unit is desired.
  • prolongators which have to be solid, preferably of steel
  • this will primarily be an option for large membranes with a long distance between the end beams.
  • the experience has shown that these prolongators shall have a high elasticity module (preferably >1 ,5x10 5 MPa) so that no movement/resonance effect is lost.
  • the transmission ratio of the device is defined, when one end is driven, as the quotient of the amplitude of the maximum oscilla ⁇ tion of the surface element 2 in said transversal direction, and the amplitude of the end divided by 2 measured in resonance.
  • the transmission ratio is defined, when two opposite ends are driven, as the quotient of the amplitude of the maximum oscilla ⁇ tion of the surface element in said transversal direction, and the amplitude of any end thereof measured in resonance. This is valid independent of driving power.
  • said sur ⁇ face element may be designed with the highest stiffness with respect to the average density thereof by introducing material portions therein having a lower density than the material form ⁇ ing the rest of the surface element or by arranging cavities therein.
  • the definition cavities also comprises recesses in the material for weight reduction or through bores having openings to the exterior, such as through bores 22 provided with an air- impearmeable material being considerably lighter, which is shown in the appended Fig. 6.
  • a portion of the surface element may be formed by at least two first layers 20 and an intermedi ⁇ ate layer 21 having a lower average density than the density of the two first layers as seen in the thickness direction thereof, as shown in Fig. 4.
  • the first layers may for example be made of carbon fibre baked into a matrix of epoxy and have a density of 1500 kg/m 3 .
  • Such carbon fibre has then a high elasticity mod ⁇ ule of about 2x10 5 MPa, preferably higher than 2,5x10 5 MPa and most preferred higher than 3x10 5 MPa.
  • the intermediate layer may be of cellular plastic having a density of about 300 kg/m 3 .
  • An alternative embodiment is to use a surface element folded in the mid region thereof, which is homogenous or made of different layers, which results in increased stiffness and a minimum of mass.
  • the surface element may be completely folded.
  • Experience has also shown that while re- ducing the stiffness in the ends the transmission ratio will be considerably increased. This may be for instance be omitted when there is an intermediate layer. This is suitable for lower frequencies.
  • Such a surface element is illustrated in Fig. 2.
  • Such a surface element having a reduced thickness in the ends is shown also in Fig. 5.
  • An intermediate layer 21 making the mid portion stiffer is present here.
  • the transmission ratio may be drastically increased and it is possible to obtain a high acoustic pressure also for low fre- quencies in the base mode or first harmonic.
  • the surface element light at the mid region thereof and heavier and stiffer at the ends preferably made of a light and stiff ma ⁇ terial as carbon fibre in a matrix where carbon fibre has a high elasticity module (of about 2x10 5 MPa, preferably >2,5x10 5 MPa and most preferred >3X10 5 MPa) enabling a high trans ⁇ mission ratio, a high transmission ratio (>6 times, preferably >8 times and most preferred >10 times) may be obtained while still staying in the first harmonic or base mode high in the frequency band, so that a high sound effect or power per surface unit may be obtained.
  • Such a construction is excellently suited as a si ⁇ ren, in which it is desired to utilise exactly a high transmission ratio at high frequencies, such as about 500 Hz, without any collapse of the membrane/surface element.
  • a high transmission ratio at high frequencies, such as about 500 Hz.
  • the experience has shown that very light membranes having a high transmission ratio give an unexpected, considerable and substantial load back on a driving unit, which makes it possible to use thick rods, since the magnetostriction material is very fragile and the experience has shown that it is easily split in thin rods. In the case that the load back from the surface element on the driving unit were low it would be necessary to use thin rods at desired frequencies as siren for high acoustic pressures.
  • Another preferred embodiment for obtaining high stiffness in combination with lightness is considerably lighter portion 27 therein, for instance by an air impermeable thin film, in which a portion or several portions form a substantial large surface 28 of the flextensional membrane and the weight thereof may be reduced substantially.
  • An alternative design may be consider ⁇ ably thinner portions of the same material or thinner portions of material having a higher density.
  • the portions 27 may also consist of material with a low density. These light portions are designed to follow the surrounding material in movement thereof. If these lighter surfaces 27, which have a limited stiff ⁇ ness, only cover a part of a flextensional membrane and at each side thereof have stiffer flextensional surfaces 28 extend ⁇ ing substantially between the ends, the flextensional membrane may have a low weight and retain a high stiffness.
  • Substantially lighter portions 27 means that it has substantially lower weight per surface unit than the rest of the portions not being light. This construction enables a high transmission ratio and gives a more efficient sound generation.
  • a plurality of surfaces 27 may also be a part and the shape thereof may vary. See the Figs. 8-11.
  • Another preferred embodiment is to make the surface element with a smaller width towards the mid region. A larger surface is then obtained which may receive the load from the mid region of the membrane and the element may by that utilise a high transmission ratio higher up in the frequency without collapsing. See Fig. 7 and 11.
  • FIG. 12 A preferred embodiment of the invention is illustrated in Fig. 12, in which an arrangement described above with a shell construc ⁇ tion 10 made of two surface elements 2 is placed between two pipe elements 11 , so that the surface elements 2 emit sound in one pipe each.
  • the surface elements may be restricted to emit in a certain direction and the desired resonances may be ampli ⁇ fied by arranging such pipes.
  • a plurality of arrangements generating sound according to the flextensional technique are advantageously arranged in a de- vice according to the invention, and these are given different resonance frequencies, so that it will be possible to obtain a very stressful signal with maximum distance action.
  • the ar ⁇ rangements may be combined with a plurality of horn construc ⁇ tions with different resonance frequencies so as to obtain fur- ther variation and resonance frequencies for an increased ac- tion.
  • FIG. 13 It is illustrated in Fig. 13 how a shell construction illustrated in Fig. 1 and described above with two surface elements 2 may be placed in a casing/pipe 12 for directing the sound 8.
  • Fig. 14 It is illustrated in Fig. 14 how such an arrangement may be placed in a linearly rising horn 13 for generating sound with a high acoustic pressure.
  • Fig. 15 illustrates how such an arrangement may be placed in a tube 14 for directed emission of sound from the two surface elements 2 in opposite directions, or the tubes are bent for emitting in the same direction. It is illustrated in Fig. 16 how two surface elements 2 has been placed in an outer casing 26 having inclined plates 23 placed towards the surface element, through which the surface ele ⁇ ments are protected, at the same time as these plates 23 func- tion as reflectors and delimit the volume at stacking. Outer sides/plates may also be bent for better acoustic performance.
  • a device having plates 23 on each side of the unit is illustrated in Fig 17, which plates delimit the power in the direction it is desired to keep it low.
  • the plates may be folded in a desired di ⁇ rection or be bent.
  • FIG. 18 A device according to a further embodiment of the invention is illustrated in Fig. 18, in which a surface element 2 is placed in a closed volume 24 to which horns 25 are coupled.
  • elements 15 may be arranged in ⁇ side a shell construction 10 having two opposite surface ele ⁇ ments 2 according to Fig. 1 behind the respective surface ele- ment, so as to delimit an air volume 16, which does not have to be completely closed.
  • the respective element 15 will in this way stop air streams from the surface element 2, so that an in ⁇ creased resonance effect and/or modified resonance frequency is obtained.
  • a substantially increased resonance effect i.e. an increased acoustic pressure
  • a substantially increased resonance effect i.e. an increased acoustic pressure
  • the element 18 should then not be tightly applied against the shell but is advantageously placed so that the surface element 2 runs freely.
  • a maximum effect is obtained for a certain dis ⁇ tance to the ends.
  • the edge of the surface element/membrane may also be received in grooves in the element 18.
  • An alternative construction consists in placing such elements in ⁇ side a shell construction, which is illustrated in Fig. 21. It is then also possible to place a plurality of such elements in suc- cession, such as illustrated in Fig. 22.
  • the different elements are advantageously designed as plates, but they may also have other designs.
  • the elements may have a bent design, for instance corresponding to the shape of the surface elements, be completely flat, wedge-shaped and so on. The surface thereof does neither have to be even but it may be undulating or the like.
  • the elements may also be placed in other angles than illustrated above and also be turned.
  • the elements used do not have to create closed volumes for obtaining resonance effect. If a sealing is desired between exterior elements and the shell construction, for example so as to create an enclosed volume, it will be possible to use a thin light film, which for instance may be glued against the shell and the elements. This film has to be so light that it will not to any larger extent influence the move ⁇ ments of the light surface elements. Such a film may also be utilised for inner elements.
  • the elements may be designed with holes and also be given an increased resonance effect.
  • the elements may then be combined with tubes/pipes/horns where the inner sound is extracted with an increased resonance effect.
  • the invention comprises also other shell constructions than having two surface elements placed in succession, such as a plurality of surface elements placed along a circle having circu ⁇ lar end beams. It is neither necessary that the driving unit of the respective arrangement is placed inside a shell construction formed by surface elements.
  • the surface element is provided with openings/cavities/slots (see for example Fig. 6) of a substantially lighter material, for instance plastic film or a thin metal film for reduced weight, and it has been given a locally reduced rate by reduced thickness.
  • the size is restricted to the length of the end beams, which gets too long for being able to efficiently be driven with a comprised driving unit.
  • Such large surface elements also gets a restricted circumferential radiation.
  • Ac ⁇ cording to a further embodiment a plurality of smaller elements are therefore placed in a triangle, rectangle, octagon etceteras to give a stiff end beam construction and a completely circum- ferential radiation or radiation around.
  • a device according to the invention is well suited for fading out or extinguishing very high acoustic pressure as so called coun ⁇ teracting sound. It may then fade out sound having very high acoustic pressures in difficult, for instance humid environments.
  • the invention is well suited for this task inter alia by the ability to work continuously at high acoustic pressures during long pe ⁇ riods of time and a membrane withstanding severe environ- ments.
  • the permanent magnets for bias magnetising may be omitted for instance in the case when a frequency doubling of a signal to the sound generator is desired.
  • the magnets may be placed outside a magnetostriction rod being part of the device, i.e. which is not excerted to a load, where the magnetic field from the magnet is led into the rod on the end/ends thereof through a magnetically conducting mate- rial, while prior art utilises permanent magnets excerted to loads.
  • the invention with light mem ⁇ brane and a high transmission ratio uses a more powerful driv- ing rod than necessary for driving the surface element entirely outwardly, this so as to obtain a desired resonance frequency.
  • the efficiency may be increased by introducing spring elements in parallel with the driving rod/ driving unit.
  • the surface element between the end beams may substantially be a part of a circular arc.
  • the end beams may be provided with holes for weight reduction for light membranes.
  • a cooling system is suitably designed by a magnetostriction material provided with holes being part of the device for tubes with cooling medium passing therethrough.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)

Abstract

Cette invention concerne un dispositif destiné à la génération d'une pression acoustique de forte puissance dans l'air dans le but de décourager les tentatives d'intrusion ou de séjour dans des lieux privés, à l'extérieur ou à l'intérieur, dans un bâtiment ou un véhicule ou tout autre lieu analogue, et ce, grâce à la production d'un signal d'alarme attirant l'attention, tel qu'une sirène. Ce dispositif comporte au moins un ensemble destiné à la production de sons fonctionnant suivant la technique basée sur la tension et la flexion d'éléments, ledit ensemble ayant au moins un élément de surface (2) dont les extrémités opposées (4, 5) sont conçues pour subir une influence qui les fait osciller en direction l'une de l'autre ou dans la direction opposée, ce qui permet à l'élément de surface d'osciller transversalement par rapport à ses extrémités et de produire un son.
PCT/SE1995/001113 1995-03-07 1995-10-02 Dispositif de production de sons WO1996027863A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU39413/95A AU3941395A (en) 1995-03-07 1995-10-02 A device for generating sound

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
SE9500833-0 1995-03-07
SE9500833A SE9500833D0 (sv) 1995-03-07 1995-03-07 Anordning, begränsad rörelse
SE9501174A SE9501174D0 (sv) 1995-03-29 1995-03-29 Sätt att anordna ljudalstrare
SE9501174-8 1995-03-29

Publications (1)

Publication Number Publication Date
WO1996027863A1 true WO1996027863A1 (fr) 1996-09-12

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Application Number Title Priority Date Filing Date
PCT/SE1995/001113 WO1996027863A1 (fr) 1995-03-07 1995-10-02 Dispositif de production de sons

Country Status (2)

Country Link
AU (1) AU3941395A (fr)
WO (1) WO1996027863A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998003964A1 (fr) * 1996-07-22 1998-01-29 Staahl Lars Dispositif generant des sons

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4001817A (en) * 1974-10-23 1977-01-04 American Electronics Corporation Ultrasonic rodent control device and method
FR2556485A1 (fr) * 1983-10-14 1985-06-14 Badens Gerard Dispositif destine a provoquer le depart des intrus (humains ou petits rongeurs) d'un local protege par le dispositif pouvant etre utilise comme antivol ou anti-rat, par emission d'un son non audible de l'exterieur du local
GB2166277A (en) * 1984-10-31 1986-04-30 Demion Electronic Company Limi Sonic pest control apparatus
US4742499A (en) * 1986-06-13 1988-05-03 Image Acoustics, Inc. Flextensional transducer
WO1993009641A1 (fr) * 1991-10-28 1993-05-13 Abb Atom Ab Boitier pour emetteur flexible a la tension
WO1994018650A1 (fr) * 1993-02-12 1994-08-18 Dick Edvinsson Procede et dispositif prevenant l'entree non authorisee
WO1995032601A1 (fr) * 1994-05-19 1995-11-30 Staahl Lars Element de surface et dispositif pour produire des sons

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4001817A (en) * 1974-10-23 1977-01-04 American Electronics Corporation Ultrasonic rodent control device and method
FR2556485A1 (fr) * 1983-10-14 1985-06-14 Badens Gerard Dispositif destine a provoquer le depart des intrus (humains ou petits rongeurs) d'un local protege par le dispositif pouvant etre utilise comme antivol ou anti-rat, par emission d'un son non audible de l'exterieur du local
GB2166277A (en) * 1984-10-31 1986-04-30 Demion Electronic Company Limi Sonic pest control apparatus
US4742499A (en) * 1986-06-13 1988-05-03 Image Acoustics, Inc. Flextensional transducer
WO1993009641A1 (fr) * 1991-10-28 1993-05-13 Abb Atom Ab Boitier pour emetteur flexible a la tension
WO1994018650A1 (fr) * 1993-02-12 1994-08-18 Dick Edvinsson Procede et dispositif prevenant l'entree non authorisee
WO1995032601A1 (fr) * 1994-05-19 1995-11-30 Staahl Lars Element de surface et dispositif pour produire des sons

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998003964A1 (fr) * 1996-07-22 1998-01-29 Staahl Lars Dispositif generant des sons
US6188313B1 (en) 1996-07-22 2001-02-13 Åm System AB Device for generating sound

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Publication number Publication date
AU3941395A (en) 1996-09-23

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