Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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WC 9g~j i3g7 PCT/GB98/02532
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TITLE: LOUDSPEAKERS
DESCRIPTION
TECHNICAL FIELD
The in~:ention relates to loudspeakers of the kind in
which an acoustic output is produced by launching bending
waves into an acoustic radiator comprising a resonant
panel. Such loudspeakers are described in International
patent application W097/09842 of New Transducers Limited.
It is an object of the present invention to provide a
modular assembly comprising a resonant panel acoustic
radiator for use as a loudspeaker or as a drive unit for
use in a loudspeaker.
DISCLOSURE OF INVENTION
Accordingly the present invention provides an assembly
com~;rising a resonant panel acoustic radiator, a body
sust~ending the acoustic radiator, at least one vibration
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exciter on the radiator to launch bending waves into the
radiator to cause i.t to resonate to produce an acoustic
outpezt, and means on the body suspending the radiator for
free movement relative thereto.
The body may take the place of a chassis in a
conventional loudspeaker drive unit, although in the
pre~~ant invention the body is usually not required to be of
the same degree of weight and rigidity as is required with
a conventional pistonic drive unit. The body (hereinafter
chassis) may be a lightweight frame-like structure.
The chassis may be such as to enclose the radiator
panEl. The chassis may be a tray-like member having a
surrounding peripheral lip. The chassis may be of light
weight and may, for example, be a plastics moulding. The
cha:~sis may be an open frame, or may be perforate.
Means may be provided for freely suspending the edges
of the acoustic radiator on the chassis. The suspension
may be such as to allow free movement of the acoustic
radi ator in directions norrnal to the plane of the radiator
(it will usually be a flat plate) while pre~renting movement
of ~i~e radiator in its plane. The suspension may comprise
arms or links hinged at one end to the chassis and at the
other end to the radiator for swinging movement about
ress-ective parallel axes at opposite ends of the arms or
links. Such arms or links may be provided on all four
sides of a generally rectangular radiator. The suspension
zrm~ or links on opposite sides of the radiator may be
attached near to diagonally opposed corners of the
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radiator. The connections of the arms or links to the
radiator may be by means of resilient foam pads, e.g. of
rub~nr or a rubber-like material, which are fixed to the
radiator, e.g. by means of an adhesive, near to its corners
arid which receive hinge pins provided on the ends of the
arms or links.
The chassis may be formed with a conduit in which
services such as electrical input leads to the vibration
excicer(s) may be located. The conduit may be in the form
of a channel extending round the periphery of the chassis .
The chassis may be formed with means whereby it can be
supported in position to form a loudspeaker or such that
more than one of the assemblies can be linked together to
forn a larger loudspeaker unit. Thus the corners of the
rhacsis may be formed with bores for receiving linking
members comprising respective pegs which are fractionally
received in the bores to hold two or more of the assemblies
together edge-to-edge to form a large loudspeaker panel.
A linking member comprising two pegs may be used to
join two adjacent modular assemblies, and a linking member
~~omy~~ising four peas may join the corners of four adjacent
modular assemblies.
The linking member may establish an electrical link
between adjacent modular assemblies as well as providing
the mechanical linkage. To provide an electrical
con::section, the pegs of each linking member may comprise
outer and inner connectors and means electrically
conr_ecting the outer and inner connectors of one peg to the
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outer and inner connectors of the other pegs of the linking
member. To establish a serial electrical connection
betr~een the modular assemblies, the inner connector of one
peg may be electrically connected to the outer connector of
ano~~her peg of the linking member. For a parallel
con~zection, the inner conductors of the pegs of the linking
member may be electrically connected and the outer
conuuctors of the pegs may be electrically connected.
The electrical signal may be carried between the
modular assemblies by making two surfaces of the chassis or
fraane moulding electrically conductive. This may be
achieved by embedding or otherwise applying electrical
conductors in the channel, for example by printing, e.g, in
the upper and lower surfaces of the peripheral lip of the
I5 cha.ss~_s. A parallel pair of conductors may be provided.
Each conductor is preferably co-extensive with the
sur~oundina peripheral lip of the chassis and may have a
con:zector pad provided at each of its i:our corners . The
ccn.,:e~tor pads are preferably received .n ~~he said bores at
eac'~ corner of the chassis and which receive the linking
T.~.er-.:~e::~s. A~.ternatively, two surfaces of the frame moulding
aan be made conductive during the moulding process, e.g. by
advanced injection moulding techniques. In either case the
cen~iuctive surfaces of the frame mou7_ding may provide a
bus.;a r for electrical connectivity between each of the
following pairs, namely adjacent resonant panel acoustic
racaiators, exciter(s) and frame, and each two resonant
pan:! acoustic radiator assembly to the outside world.
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The resonant panel acoustic radiator may comprise a
member having capability to sustain and propagate input
v-ib~ational energy by bending waves in a least one
operative area extending transversely of thickness to have
5 resc.~nant mode vibration components distributed over said at
least one area and have predetermined preferential
locations or sites within said area for vibration exciter
means and having an exciter mounted on said member at one
of said locations or sites to vibrate the member to cause
is ~:o resonate farming an acoustic radiator which provides
an .coustic output when resonating.
'~'he or each vibration exciter ma~,r be of the kind
described in our International patent application
W093.31188, which describes a vibration exciter which can
he 1=reely or resiliently suspended on a support, e.g. the
body or chassis of the present invention.
BRIEF DESCRIPTION OF DRAWINGS
i:~e invention is c~iagrammatica115T illustrated, by way
of example, in the accompanying drawings, in which:-
Figure 1 is a perspective cross-sectional view of a
~o:x_.=va.r loudspeaker_ drive unit;
Figure 2 is an exploded perspective view of the
moc:-zlar assembly of Figure 1;
,:vgure 3 is a perspective view showing the interior
f.acz of a basket or chassis for the modular assembly of
Fig',~.re 1, and
Figure 4 is a perspective view of a resonant acoustic
:~ac~ ~_at:o~ panel for the modular assembly of Figure 1;
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Figure 5 is a perspective view of two interconnected
modular assemblies;
Figure 6 is a perspective view of four interconnected
modular assemblies;
Figure 7 is an enlarged scrap perspective view of a
linking member interconnecting two modular assemblies;
~'i.gures 8 is an enlarged scrap perspective view of a
1=~n:.-_ing member and a corner of one modular assembly;
Figure 9 is an enlarged scrap perspective view of a
:Lin.~~~.ng member interconnecting four modular assemblies;
~?igure 10 is an enlarged scrap perspective view of a
l~.nl~irg member and the corners of two modular assemblies;
~~igure lla,llb,llc are respective perspective views of
p~.r_:~~llel and serial linking members;
Figure 12 is an exploded perspective view of the
mad°m ar assembly of Figure 1 with the addition of a pair of
bus's>a~~ s ;
:.:.~igure 13 is a perspective view of a connector pad,
and
Figure 14 is a parties'. crass-section through a pair of
;;~c.u7.ar assemblies and a linking member connecting them
toget?zer .
BEST MODES FOR CARRYING OUT THE INVENTION
Figures 1 to 4 illustrate a flat generally rectangular
m~oawla~_ 1 oudspeaker drive unit assembly (1.) comprising a
general~.~y rectangular ;tiff lightweight resonant acoustic
radv~tor panel (2), e.g. of the kind described in
Incer~ational patent application w097/09842 mounted in a
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surrounding generally rectangular body in the form of a
chassis or basket (3) with a pair of vibration exciters (4)
mountEd on the panel (2) to launch bending waves into the
par_el (2) to cause it to resonate to provide an acoustic
output.
The chassis (3) encloses the radiator panel (2) and is
forr~;ec~ with a surrounding outwardly facing conduit (14)
defined between outwardly projecting flanges (11) in which
serTrices such as electrical input leads to the vibration
exciters (4) can be located. The conduit (14) is thus in
ttve l:orm of a charnel extending round the periphery of the
chassis (3).
Figures 1 and 2 also illustrate a means (7) for freely
suspending the acoustic radiator (2) on the chassis (3) by
= t s e~~c es . The suspension ( 7 ) comprises arms or l inks ( 8 )
hinrec? at one end to the chassis (3) and at the other end
to '_he radiator (2) for swinging movemera about respective
paral~.el axes at opposite ends of the arms or links (8).
The connections of the arms or links (8) to the radiator
(2) i~ by weans of resilient foam pads (10) each formed
ia-_ ;:~:. a k~ore ( 2 6 ) , whi ch receive hinge pins ( 9 ) provided on
one Fnd of each of the arms or links (8). The other end of
each ,arm or link (8) is formed with a cyn_indrical boss (24)
recW~,red in a corresponding aperture (2.9) on the chassis
(3i. The suspension (i) is such as to ~xllow free movement
of tY~e acoustic radiator (2) in directions normal to the
pla-~e ~~~:~ile preventing mozrement of the radiator (2) in its
p.'_:zr .~::
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~s shown in Figure 2, a pair of inertial electro-
dynamic vibration exciters (4) are coupled to the radiator
(2) ro launch bending wave vibration into the radiator. The
exc~i~.~~s (4) are suspended on the chassis (3) such that
thei.r_, motion normal to the plane of the radiator (2) is
unimpeded and to prevent movement of tr~e exciters in the
plane of the radiator (2) whereby centring of the
rels~.~~vely movable parts of the exciters is ensured. This
excit.e-r suspension is the subject of International patent
aprJi.ication W098/31188.
'This suspension resFmbles, at least in function, the
spiaer commonly found in the drive units of conventional
pistonic loudspeakers, and is in the form of a disc-like
plate (5) having an inner portion attached to the exciter
arvd =r~ outer portion attached to the chassis, the inner and
outer portions being separated such that the one can move
nor~ma!ly with respect to the other anti so that relative
movement in the plane of the disc-like plate is prevented.
Tha_s is achieved by forming the disc (5) with
c~_~_rc:smferenti.al and radial slits (30,32) respectively to
f:.-,y~., _. pair of curved =_imbs (33) the free ends (31) of
wh.w',z ~Le cttached to the chassis. Fcr this purpose the
chassis (3) is formed with a plate-lik.~ exciter locating
port ion (23) formed with. opposed apertures (25) ~,ahich align
2 5 vas. '=h ar_d surr ound the r. espect ive excit ers ~ 4 ) and to which
porti~;,n (23 ) , the free ends (31) of the limb s (33 ) are
at v.::zcired. A. heat sink (6) is attached to each exciter over
the top oz the plate (5); to assist in cooling the exciters
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during use.
rigure 3 shows the interior face of the basket or
cr_as~s.is (3) . The chassis (3) is a tray-like member
cc~rryJr~sing a perforate plate-like member (34) having an
un~~Wan3ing rim (=~5) which carries the surrounding pair of
outwardly extending flanges (11) which define the conduit
(~.4). The chassis (3) is lightweight and may, for example,
be a plastics moulding.
,:figure 4 illustrates the positions of the resilient
to~:n pads (10) on the acoustic radiator (2). The foam pads
com~;rise bores (26) to receive hinge pins (9} provided on
tre ends of the arms or links (8) of the means (7) for
su::bending the edges of the acoustic radiaLOr (2) on the
cr~assis (3) . The foam pads (10) are positioned on all four
«o<~:~ of the radiator (2) and the foam pads (10) on
cpposite sides of the radiator (2) are attached near to
do_a~~cnally Qpposed corners of the radiator (2). The
nes il:_ent foam pods ( 10 ) which may be ef rubber or a
rub;~E_-like materv_al, az-e fixed. to tr.e radiatcr (2) , e.g.
b~r z~~=;ans of an adhesive .
Figures 5 and 6 illustrate respectively the
:.nt er_~~onnection of the chassis (3) of t-.wo and four of the
;ro~.~a.:Lar assemblies (1) of Figures 1 to 4. To this end the
_.~:rnErs of the rhassi~ are formad with bores (15) for
r-.diving 1~_nkinc members (16,18) comprising respective
peas ( 17 } Y~rhi.ch are f rz.ct Tonally rece ~.ve~3 i.n the bores ( 15 )
co :!~c~ld the two assemblies together edge-to-ed<~e to form a
~la.:~ye _l.ou3speaker panel. The linking member (16) comprises
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two parallel pegs and is used to hold two
modular
asvemhlie~ (1) together. The linking member (18) comprises
fo~.w raral~..el pegs arranged in a square formation. A
c~~r~bima ~ ion of the 7_ inking membErs m.ay be used
( 7. ~ , 18 ) to
5 hole; ':our assemblies together.
H'i gure 7 illustrates the detail of the linking member
(15i of Figure 5 which comprises two parallel pegs
(17~ ~'~7) interconnected by a web or arm (27). The two
pe:~.~~ (17',17") are trictionally received in the bores
10( ~1_ ~~ ' , 15" ) to intercannect two modularl ies ( 1 )
assemb of the
kind shown in Figures 1 to 4.
Figures 8 to 10 illustrate the detail of the linking
me:nr_~e_ (18) of Figure 6. As can best be
seen in Figure 8,
t:he lin)ting member (18) comprises four
pegs (17)
15: P~ :~rw~onnected by a cruciform: web (28; Tr~~ web (28)
.
ccmpr~ses a generally rectangular central body (38) and
four: arms (39) which extend from the four corners of the
re~ta~~g,-~~.ar body (38) . Each peg (1'7
i is f.rictionally
r~~~i_zYe-~ ;_n a bore= (15) at the corner chassis (3)
of th~ of
20G ~;-:>c:u:l ~r assembl,r ;1) of Figures
1 tc 4 .
,Figure 9 illu.strat:es h.ow faur nm~dL,lar assemblies (1)
a ~~a i. ~:.t.erconnectec~ by a linking memberwhich has each
; l8 )
of its pegs (17) frictional:ly received ire
bores (15) at the
~.:_rwer_ s of th.e modular assemblies (._
) .
25L figure i0 i:'~l,.astrates the detai is the bores (15)
of
~,~~.-. rn zrict.ionally receive ~.he pegs The bores (15)
( i7 ~ .
are qwr~eral:!y r_yLinc.rical with a reG""t~~:'lgl).~.ar
groove (40) to
re.=::ire the arm (~9) of the web (28) which
interconnects
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the p=:g~ ( 17 ) .
t~igures 11a,11b and llc are perspective views of
serle~and paralle'y ccnnected linking member (16), which
~.r ~. wsecz to es~ax;li_sh an electrical link between adjacent
acoustic radiators. As can be seen ~~I1 Figure 11c, the
~n..i=~_g member ( 16 ) comprises two pegs ( 17 ' , 17 " ) each of
which comprise an outer electrical connector (20), and an
innEr electrical connector (19) arranged in a co-axial
c~~~fiquration.
~:n Figure 11a, a serial electrical. connection between
tr~e assemblies (1) (not shown) ~:~ established by
elec_~trically connecting via conductor w~_.res (21) , the inner
corme~tors (19,19') of each peg (1'7',7") to the outer
con~-.e~:tc>rs (20, 20' ) of the other peg (1n' , l_7") . In Figure
l~.k-, ~ parallel connection is established by electrically
cer.r~ec_ti:~g via conductor wires (2.1) 'he inner conductors
(1.a.1:~'; of each peg (17',17") and by electrically
ccnne-~t=_ng via conducte-r wires (21) the outer conductors
(20, 2 ~i' ) of each peg (17' , 17" ) .
ig;zre a.2 il ;.ustra.tes tre mc;dular a.r>cembly (1) , with
~~~p :sec. pa~=_r of conductor ra_Lls cr busbars (12, 13) ,
-~7;~.~.:,:~ ~.re ,~~;~unt.e~.3 on or located .n c> >mbedded in the
;'rw ;r ~ :l3 ;, to surround the chassis . One conductor ( 12 )
may ~e pc-sit: rely charged and the other conductor (13) may
~e negatively polarised. to carry the lectrical signal
b~t;~ecrs adjacent assemblies (1). The conductors (12,13)
a~_w ~o-ext ~_ nsive with the per .iphera l l ip ( 11 ) of the
c~,.ass i s ( 3 anC have connector pads ( 22 ) at each corner and
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wh:icr pads are arranged to fit into the bores (15) at each
corr.~ei: ef the chassis ( 3 ) , for el~~ctri cal. contact with the
liml-;irk members illustrated in FigurFe: lla,lLb and llc
a~<.w:~-
fiigure 13 illustrates the detail of a connector pad
(2~) ~~t the corner of a conductor (12). The connector pad
(2z) ~~omprises a ~~ircular rind {36) an~~l a link {37),
attGc:!~aing the ring (36) !.o the conriectcr pace. (22) .
i.s shown in Figure 14, the ~~usbars 612,13) are
e__f:~a:_ic:ally connected to the elec~~rical connect~_ons of the
lin~in~ members (16,18) by means of screws (41) which
engage thz~eaded inserts (42) in the linkir_g members to hold
the linking members in the bores (15i in the assemblies
(1~. Trle screws (41) thus ensure noth. the mechanical
co:an~~t:ion of Lhe assemblies ~1) and the electrical
ccn~.ileetioizs between the assemblies .
INDUSTRIAL APPLICABILITY
'e"hn invention thus wrovides e. ~,imple manner of
ad~.~~t_.nc resonant, panel acoustic radiators for mass
p.r~~uicn and fog- electrically r.or..-~ecting interlinked
ac ~;a :> ~.. ~ c radiators .
