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
  • G10K9/13—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated using electromagnetic driving means

Definitions

• This invention relates to an electronic horn for a vehicle.
• this invention relates to an electronic horn having a chip on board (COB) circuit for contactless switching protected against surges and high vibration environment.
• COB chip on board
• Conventional horns used in automotive vehicles have a vibrating diaphragm driven by an electromagnetic device.
• the said electromagnetic device is a coil driven by current pulses.
• Current pulses are developed by a mechanical switch such as a circuit breaker wherein such switch would energize a magnetic coil to cause the diaphragm movement.
• Diaphragm movement during its travel would open the switch, allowing the diaphragm to return in the reverse direction due to the elastic energy accumulated in the diaphragm thus closing the switch again.
• Switching and corresponding movement of the diaphragm causes the cycle to repeat at a particular frequency equal to the fundamental frequency which can be adjusted by a screw.
• Objects of the invention It is an object of the invention to provide an electronic horn with surge protected contactless switching system such that the life cycle of the horn is increased and its operation is simplified.
• an electronic horn for a vehicle comprising a housing sub-assembly; a diaphragm sub-assembly and a chip on board circuit riveted to a terminal block outside the housing.
• the said chip on board circuit having clipping means for eliminating surge voltages.
• Figure 1 illustrates a schematic circuit diagram of a solid state energizing circuit on a printed circuit board of the prior art.
• Figure 2 illustrates a cross sectional view of the housing sub assembly for an electronic horn according to the present invention.
• Figure 3 illustrates a cross sectional view of electronic block sub assembly according to the present invention.
• Figure 4 illustrates a cross sectional view of the diaphragm sub assembly for disc type electronic horn according to one embodiment of the present invention.
• Figure 5 illustrates a cross sectional view of the diaphragm sub assembly for trumpet type electronic horn according to one embodiment of the present invention.
• Figure 6 illustrates a block diagram of the chip on board circuit of the electronic horn according to the present invention.
• the present invention provides an electronic horn.
• the electronic horn according to the present invention is now described in detail with reference to the accompanying drawings, wherein reference numerals used in the accompanying drawings correspond to the like elements throughout the description.
• Figure 1 illustrates a schematic circuit diagram of a solid state energizing circuit on a printed circuit board of the prior art.
• a power supply is provided through a battery to a voltage regulator.
• Output from the said voltage regulator is further coupled to a timer through a limiting resistor for generating a pulse wave having frequency similar to the resonance frequency.
• the timer is connected to an adjustable resistor for varying the timer output frequency as well as the duty cycle.
• Output of the timer is further connected to a switching device, which is a MOSFET having its source connected to the ground and its drain is coupled to the coil.
• Positive terminal of the power supply is further connected to the other end of the coil.
• FIG. 2 illustrates a cross sectional view of the housing sub assembly (101) for an electronic horn according to the present invention.
• the housing sub- assembly (101) comprises a cup shaped housing (102) and a coil body assembly (116).
• the cup shaped housing (102) is made of metal or plastic casing to protect inner components which are safely secured inside the housing (102) from being damaged.
• the housing (102) is stepped to define a small closed end portion (106) comprising an end wall (108) and a larger open end portion (110) terminating in a radial flange (112).
• the small end portion (106) and the larger end portion (110) are connected by means of an intermediate section, such as a planar annular portion (114).
• the coil body assembly (116) is provided for mounting an energizing coil (129) which generates a magnetic field inside the housing (102).
• the coil body assembly (116) is engaged with the housing (102) by rivets (122) through the apertures (not shown) provided in the annular portion (114) and the coil body assembly (116).
• the rivets (122) through the coil body assembly (116) and the housing (102) are also connected to an electronic block sub-assembly (not shown) having a chip on board circuit (not shown) placed inside a terminal block (130).
• the chip on board circuit (not shown) is placed inside a metal casing (not shown) to protect the chip from being damaged.
• the chip on board circuit (not shown) may be in any form, however an arc shaped chip on board fits easily above the annular portion, (114) of the said housing (102).
• the casing (not shown) and said terminal block (130) are also provided with a similar shape as that of the chip on board, so that said chip on board is placed properly inside the terminal block (130).
• the casing (not shown) may be plastic or metal casing made of non heat dissipating material so that the heat generated in the housing due to reciprocating movement of the diaphragm is not transmitted to the chip on board circuit (not shown) inside the metal casing (not shown) .
• the rivets (122) are basically mechanical fasteners having a factory head and a buck tail. Different types of rivets may be used for the fastening purpose such as solid rivets, blind rivets, multi grip rivets, grooved rivets, peel type blind rivets, self pierce rivets, plastic rivets, tubular rivets and the like.
• the rivets (122) provide better fastening between the housing and the chip on board circuit (not shown) placed inside a metal casing (not shown) compared to click fitted PCB used in the prior art where the click fitted PCB used to fail during conditions of high vibrations associated with the vehicles.
• the terminal block (130) has shape similar to that of the chip on board circuit (not shown) and provides covering to the chip on board circuit (not shown).
• the terminal block (130) receives the rivets (122) through the chip on board circuit (not shown) and has terminals (142) to connect an external power supply (not shown) through a battery, to the chip on board circuit (not shown) inside the metal casing (not shown) .
• An aperture (not shown) in the end wall (108) of the housing holds an anchor bolt (126) which extends towards the coil body assembly (116).
• One end of the anchor bolt (126) receives the coil body assembly (116) and the opposite end of the anchor bolt (126) is threaded to receive a mounting bracket (128).
• the mounting bracket (128) is further secured with a securing nut (134) so as to connect the said housing to the vehicle body.
• the anchor bolt securely connects the said mounting bracket with the vehicle so that vibrations associated with the vehicles do not affect the secured connection between the housing (102) and the mounting bracket (128).
• the coil body assembly (116) of the housing sub assembly (101) has an energizing coil (129) , which is secured inside the cup-shaped housing (102) by means of said rivets (122) connected through the apertures (not shown) inside the coil body assembly (116) and the cup- shaped housing (102).
• the energizing coil (129) is made up of a conductor such as a solid copper wire or the like and wound around a core to form an inductor or electromagnet.
• the coil (129) is further coated with varnish or wrapped with an insulating tape to provide insulation and to secure the wire in place.
• Said coil (129) acts as an electromagnetic driver when current is passed through it and is connected to the output of the chip on board circuit (not shown).
• FIG. 3 illustrates a cross sectional view of the electronic block sub assembly (140) according to the present invention.
• the electronic block sub assembly (140) comprises of a terminal block (130) placed above the COB (132) and covering the said chip on board (132) placed inside a metal casing (133), so as , to protect the COB (132) from getting damaged.
• the chip on board circuit is (132) placed inside the metal casing (133) and upon the planar annular portion (114) which interconnects the smaller end portion (108) and the larger portion (110) of the housing (102).
• the chip on board circuit (132) comprises of a printed circuit board (PCB) (180) having an embedded chip (182) like a layer of chip wafer.
• the chip on board also comprises of, linear elements like resistors and non-linear elements like junction diodes mounted on it.
• the PCB (180) along with other elements mounted on it are further placed inside a metal or plastic casing (133) which does not dissipate heat and thus does not allow the characteristics of electronic components to vary with changes in the temperature.
• the terminal block (130) and the chip on board circuit (132) are connected to each other and the housing by means of rivets (122) through apertures (138) in the terminal block (130) and chip on board circuit (132).
• the chip on board circuit (132) comprises of a solid state switching circuit which is provided inside an electronic circuit casing (133) and is located outside the cup-shaped housing (102).
• the electronic circuit casing (133) may be of any form, nevertheless, in general the casing (133) has the shape of an arc which : easily fits on the planar annular portion (114) of the housing inside the
• terminal block (130) is made of plastic or metallic material which does not allow the heat produced inside the housing to dissipate to the chip on board circuit (132) and prevents heating of the riveted, casing (133) from the heat generated inside the housing (102) thus preventing damage and malfunction of said electronic circuit.
• the terminal block (130) comprises of terminals (142) connecting an external power supply (not shown) to provide desired electric current to the chip on board circuit (132) which is further connected to said energizing coil (129).
• the chip on board circuit (132) provides an electrical output to the energizing coil (129) mounted on the coil body assembly (116) thereby magnetizing the energizing coil (129). Riveting of the said chip on board circuit (132) inside the metal casing (133) with the housing (102) increases the life of horn by reducing failure from dislocation of the chip on board and loosening of connections between different components of the chip on board during jerks and vibrations in the vehicle.
• FIG. 4 illustrates a cross sectional view of the diaphragm sub assembly for disc type electronic horn according to one embodiment of the present invention.
• a diaphragm sub-assembly (151) comprises a diaphragm (150) made of a resilient metal with good elastic properties and an armature (152).
• the diaphragm (150) is made of a material such that when the coil (129) is energized by passing current through it, a magnetic field is generated around the coil (129) which pulls the diaphragm (150) and the armature (152) towards the energizing coil (129).
• the armature (152) is riveted to the diaphragm (150) along with a resonator plate or an oscillator (154).
• the diaphragm (150) is clamped to the periphery of the radial flange (112) in the cup shaped housing (102).
• the resonator plate or the oscillator (154) is further secured to the second sub assembly by a nut (156) with a cap cover (158).
• Said oscillator (154) is responsible for producing metallic sound inside the disc horn and this metallic beep sound distinguishes disc horns from other horns.
• the housing sub-assembly (101) is then assembled together with the diaphragm assembly (151) by a sealing ring (168).
• the electromagnet is excited again by the chip on board circuit (132) in the same manner leading the diaphragm (150) to commence a new oscillation cycle at the same frequency as that of resonance frequency of the electronic chip on board circuit (132).
• the switching action in the system is completed by chip on board circuit (132) which results in reciprocating movement of diaphragm (150) along with the oscillator (154) resulting in sound generation by the horn.
• FIG. 5 shows a cross sectional view of the diaphragm sub assembly for trumpet type electronic horn according to another embodiment of the present invention.
• Diaphragm sub-assembly (151 1 ) comprises a metal diaphragm (150 5 ) and an armature (152*).
• the armature (152*) is connected to the diaphragm (150*) by riveting it to the diaphragm (150% Metal diaphragm is clamped to the periphery of the radial flange (112) in the housing (102).
• a packing disc (170*) is provided for better packing between the disc plate (160*) and the diaphragm (150") so that the air pressure generated inside the diaphragm assembly (151") is not released and is fully transferred through the disc plate (160") to projectors (172 1 J for obtaining maximum sound output.
• the disc plate (16O 1 ) has an aperture (not shown) in the centre to transmit the pressure produced inside the diaphragm assembly (151 s ) due to reciprocating movement of the diaphragm (150*) to the projectors (172 5 ).
• dimensions of the projectors (172" are varied accordingly.
• FIG. 6 is a block diagram of the chip on board circuit of the electronic horn according to one embodiment of the present invention.
• the chip on board circuit (132) may be used in different types of horns available and need not be limited to electronic horn comprising a switching circuit (602) coupled to a battery (600) for providing switching action.
• Switching circuit (602) provides a pulse train having frequency similar to the resonance frequency of the diaphragm assembly to a driver circuit (604).
• Switching circuit (602) has a clipping circuit (606) having a clipping means for completely clipping surge voltages which are generated in high frequency inductive coil circuits. Either a series or shunt clipper can be used as a clipping circuit. Normally a resistor in combination with a diode is used but such circuit does not provide proper protection to the entire electronic circuit components from the surge voltages
• present invention clipping means is a transil diode connected in the clipping; circuit (606) to provide better clipping.
• the clipping circuit (606) has the transal : diode which totally eliminates surge voltage generated due to inductive loading : v and provides better protection to the electronic circuit components from damage and malfunction.
• the clipping circuit (606) is further connected to a ; timer in the switching circuit (602) for outputting pulse train having frequency > similar to the resonance frequency of the diaphragm assembly.
• timer circuit is normally an IC 55S or IC556 or an operational amplifier.
• Output from the timer is coupled to a switching means to provide switching at a frequency similar to the resonance frequency of the electromechanical system.
• switching means may be a Metal Oxide-Semiconductor Field Effect Transistor (MOSFET) connected to the driving circuit.
• Output of the switching circuit (602) is provided to the driver circuit (604), wherein the driver ! ⁇ circuit (604) comprises of an energizing coil mounted on the coil body assembly , of the horn and an electromagnetic means for energizing the coil (129)., '
• the energizing c ⁇ (129) mounted on the coil body assembly is energized by electromagnetic means by passing current through the coil (129). The current thereby produces a magnetic field around the coil which pulls the diaphragm towards the coil ! (129).
• the coil body assembly (116) and the anchor bolt (126) get magnetized simultaneously upon being energized by electric current and thereby puffing

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Multimedia (AREA)
• Electromagnetism (AREA)
• Apparatuses For Generation Of Mechanical Vibrations (AREA)
• Mounting Of Printed Circuit Boards And The Like (AREA)
• Measuring Fluid Pressure (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2009
  • 2009-09-25 EP EP09745102A patent/EP2342709A2/de not_active Withdrawn
  • 2009-09-25 WO PCT/IB2009/006968 patent/WO2010035123A2/en not_active Ceased

Non-Patent Citations (1)

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