Note: Descriptions are shown in the official language in which they were submitted.
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_ BACKGROUND OF THE INVENTION
2 Field o~ the Invention
. . .
3 The presen-t invention relates to loudspeakers and
4 more particularly to dual spider arrangements for use in
combina~ion with the loudspeakers.
6 Descri~tion of the Prior Art
7 U. S. Patent No. 2,812,825, entitled Loud Speaker
8 Diaphragm Supporting Member, issued Charles L. Matthews on
9 November 12, 1957, teaches a m~mber for supporting a
moving coil in an electro-acoustical transducer and for
11 centering suc~ coil in an air gap in such transducer. The
12 member includes a corrugated disc of resin-impreg~ated,
13 thin, resilient, porous cotton ~abric and an external film
14 of modi~ied po~yv1nyl chloride type resin on ~he surface o~
~e disc-to fill the pores in the cotton.
16 U~ S. Patent No. 2,641,329, entitled Loudspeaker
17 Diaphragm with Trznsversely Arched Sti~fener Means, issued
18 to Sidney E~ Levy-and Abraham B. Cohen on June 9, 1953
19 teaches an acoustic diaphragm for loudspeakers, that ~
an acoustical energy-responsive diaphragm member of 9ubstan-
21 tially conical ~orm having a relatively rigid transversely
22 arched stiffener member secured at its ou~er marginal edge
23 to an intenmediate por~ion of the diaphragm mQmber and
24 extending across the latterO The stifener member has a
~5 plurality of rela~ively small sound-radiating per~orations
26 therethrough, the per~orations of t~e stiffener member
27 being spaced from each other and each perforation
~8 having its axis inclined at an angle t~ the central axis
~aS
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of the diaphragm member. The perorated sti~fener memb~r
2 has the property of directional control o~ high freguency
3 propagation generated from the center of the diaphragm
4 member.
U. S. Patent No. 3~905,448, entitled Loudspeaker,
6 issued to Hirotake Kawakami, Toshio Sasabe, Toshio Hirosawa,
7 Nobuyaki Arakawa, Kozo Kok~lbu, Kazumasa Abe and Toshiko
8 Harashino, on September 16, 1975 teaches a loudspeaker with
9 a suspension device for supporting the diaphragm from its
rame. In the loudspeaker, ~he upper part and the lower part
11 of a oone~shaped diaphragm with a voic~ coil ax~ suspended
12 ~rom a frame by a ring-shaped suspension member, herein
13 referred to as a first suspension means, and by ~ ring-shaped
14 suspension member, hexein referred to as a suspension means,
respectively. At least one o~ the suspension means is formed
16 of a mixture-o~ elas~ic material such. as rubber, with carbon
17 fibers therei~. The fibers are needle-like and are aligned
18 radially in the material of at least one of the suspension
19 means.
U. S. Patent No. ~,767,004, entitled loudspeaker,
21 issu~d to Arthur Liebscher on October 23, 1973, teaches
~2 a loudspeakex that is provided in which a thin surround
23 is employed ~or the speaker cone o impervious foam material,
24 the surround being characterized by omni-directional elastic
tension and ~eing secured between the cone and the support.
26 The loudspeaker also has a pair o:E spaced coaxial
27 supports which support the coil~ The.supports have radial
28 rigidity and high axial flexibility so that the surround
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serves no supporting function and acts prim~rily as an air
2 separator at the periphery of the diaphragm.
3 Abraham B. Cohen has written an article entitled,
4 The Mechanics o~ Good Loudspeaker Design, published in
Volume 2, Number 3, July, 1954, Journal of the Audio
6 Engineering Society on pages 176 to 1~2. In his article
7 he discusses a double spider to correct voice coil mis-
8 aligr~ment as follows:
9 "~aving thus dealt brie~ly with one of the unrecog-
nized causes of gap and voice coil misallgnment, we must
11 complete the study of the problem by considering the more
12 commonly recognized cause o such misalignment. Damaging
13 eccentric and rocking motion o the voice coil about its
14 axis of motio~ will occur while it iS vibrati~g, if the
means used to maintain accuracy o~ such motion are inade~uate
16 to meet the mechanical re~uirements i.mposed on the
1? system by the laxge power ou~put expe!ctea of it. The
18 usual means lor preventiny such side swaying of the voice
19 coil motion ~s-khe well known spider located directly at
the voice coil area. There is a new and exceedingly
21 successful 501utio~ to the problem of maintaining preclsion
22 voice coil alignment during vibration. Placement o~ two
23 axially spaced spiders at the apex area of the vibrating
24 system provides a dual guLde to the vibrating system that
keeps the voice coil motion rigidly channeled along one
26 line of vibration ~hat neither deviates in an~ular direction
27 from th~.central axis nor becomes eccentrically located
28 in respect to this axis."
, ~ .
1 In his book, Hi-Fi Loudspeakers and nclosures,
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2 2nd Edition, Abraham Bo Cohen further describes a dual
3 spider arrangement on pages 87 to 88 in which he states:
4 "The mechanical precision with which the suspension
holds the whole assembly together determines the mechanical
6 longevity o~ the voice coil itselfO The voice coil must be
7 kept per~ectly aligned mechanically in its magnetic gap at
8 all ~imes during its vibration cycle. If, during its
9 vibration, it sways or twists sideways, it may scrape
itself against the walls of the gap, causing rubbing of
11 the voice coil, which in turn results in distortion,
12 in shorted turns, and sooner or later, in a~ open voi~e
13 coil. Althoug~ the spider is norc~mlly the device that
14 keeps the coil centered in the gap when no motion is involved
it is the combination of the spider cmd the other cone
16 suspension that dictates how the cDil behaves in the gap
17 under mo~ion~ Obviously, even though the spide.r may ~eep
18 the coil cente~ed, if the cona tilts, it will tilt the
19 coil and cause rubbing. Where small motions are involved,
as in tweeters, t~is condition does not present a
21 pxoblem. ~owever, in the case o~ woo~ers, where voice
22 coil motions of t~e order of 3/8 inch or more are prevalent,
23 added insurance against voice coil misalignment may be had
24 by the double spider suspen~ion. The addition of ~he
second stabil;zing spider part way up ~he cone o~ the
26 speaker acts as a second guide to the linear in and out motion
27 of the voice coil, keeping the voice coil not only rigidly
28 centered, but also moving in a rigidly prescribed axis."
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1 "In loudspeakers in which the voice coil travels a
2 straight and narrow path, and in which the side play of the
3 coil is rigidly controlled, the clearances betw~en the
4 overall gap walls and the voice coil may be reduced,
with resultant improved magnetic circuit e~flciency, because
6 of the reduced gap cross-section. Thus we see again that
7 the final acoustic performance of the loudspeaker is a
8 function of the mechanical toleranc s permissible between
9 co~trolled moving parts."
There have been several other loudspeakexs that
11 have incorporated dual spiders for supporting their
12 ~iaphragmsO Th.e di~iculty with these dual spiders is
13 tha~ their m~nufacturer is unable to adjust the linearity
14 of the loudspeakers' response after manu~ac~ure thereo~.
The two exter~ally placed spiders are disposed in a fi~ed
16 position. It would be ~deal to provi.de an adjustable
17 spider for loudspeakers that can reduce the bias in the
18 response ~hereor.
19 SUMMARY OF T~E I~VENTION
In view of the foxegoi~g factors and conditions
21 characteristic of the prior art~ it is a primary objec~
22 of the present invention to provide an adjustable internal
23 ~pider ~or use in combination with a loudspeakex having
24 an ~xtexnal spider me~hanically coupling its frame to th~
base of its diaphra~m.
26 It is another object of the present invention
27 to provide a dual spider arrangement that not only eliminates
28 lateral movement, but also provides more truly axial or
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.... ....
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linear movement by having a larger lateral separation
2 between the dual spiders.
3 It is still another object of the present invention
4 to provide an internal spider that functions as a dust cap
thereby reduciny the number of components re~uired in the
6 loudspeaker.
7 It is yet skill another object o~ the present
~ invention to provide a clamp system that allows lateral
9 spider adjustment in order to correct a faulty assembly
that is incapable o~ true axial motion withouk remanu~acturing.
11 In accordance with an embodiment of the present.
12 invention, an internal stabilizing spider-dusk cap for use
13 in combination wi~h a louaspeaker that has an external
14 .centering spider and a surround mechanically coupling the
conically shape-~ diaphragm of the loudspeaker to the frame
16 thereof has b~en described~ The loudspeaker includes a pole
17 piecej a gap plate, a pole plate of :Lron and a ring-shaped
18 magnet which are separated hy a cylindrical voice coil
19 msmber and a voice coil, which is disposea about the voice
coil member, an~ which provides a magnetic gap for the voice
21 coil. The centering spider aligns the voice coil within
22 the magnetic gap~ The stabilizing spider is mechanically
2~ coupled to th~ internal sidewall of ~he conically shaped
24 diaphragm and to a rod which is disposed perpendicularly into
the pole piece. The center of the s~abilizing spider is
26 mechanically clampe~ to the rod by a mounting plate de~ice
27 which is secured in place by a set screw in one embodimenk so
28 .that ik may be ra.ised and lowered in order to modify the
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1 compliance linearity of the existing suspension. A lateral
2 adjustment may also be provided to increase e~fective
3 excursion and to correct for faulty assembly.
4 The featur~s of the present invention which are
believed to be novel are set forth with particularity in
6 the appended claims.
7 Other objec~s and many of the attendant advantages
8 will be more readily appreciated as the same becomes better
9 unders~ood by reference to the following detailed description
and consid~red in connection with the accompanying drawing
11 ~n which like reerence symbols designate like par~s through-
12 out the ~i~ures.
13 DESCRIPTION OF TEE DRAWING
14 FIG. 1 is a perspective view of a first loudspeaker
having a dual spider which has been constructed in accordance
16 w.ith the principles o the present invention.
17 FIG. 2 is a side elevatio~al view of the loudspeaker
18 of FIG. 1
19 FIG.- 3 is a side cross-sectional view of the loudspeaker
of FIG. 1 t~ken along line 3-3 of ~IG. 2.
21 FIG. 4 is a partial top plan view of the loudspeaker
22 o~ FIG. 1.
23 FIG. 5 is a partial ~o~tom plan view of the loudspeaker
24 of FIG. 1.
FIG. 6 i~ a cross-sectional side view of a ~irst
26 clamping apparatus for an internal stabilizing spider for the
27 loudspeaker of FIG. 1.
28 FIG. 7 is a cross-sectional side view o a second
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_, _ .... , .. ..... .. _ _ _ _
1 clamping apparatus for an internal stabilizing spider ~or
2 the loudspeaker of FIG. 1.
3 FIG. 8 is a side cross-sectional view o~.a second
4 loudspeaker having a dual spider which has been constructed
in accordance with the principles of the present invention.
6 FIGu 9 is a side cross~sectional view o the loudspeaker
7 having a dual spider which has been constructed in accordance
8 with the principles of the present invention.
9 DESCRIPTION OF TME PRE~ERRED EMBODIMENT
The present invention can best be understood by
11 reference ~o a descrip~ion of its preferred embodIment and
12 to the showings in the drawing. The invention is an
13 improvement for use in combination with a loudspeaker 10
14 shown in FIG. I to provide an adjl7stable stabilizing spider
11. The loudspeaker 10 includes a conically shaped diaphragm
16 12 having a front peripneral edge 13, an external sidewall
17 14, an internal sidewal~ 15 and a has~ peripheral edge 16
18 and a frame 17 ha~ing a conically shaped portior~. adapted
19 to receive-the diaphragm 12 and a front plate ~J The
2G loudspeaker 10 also include~ a surraund 19 which mec~anically
21 couples ~h~ f7 ont peripheral edge 13 of the diaphragm 12 to
22 the frame 17.
23 Re~rring now to FIG. 2 the loudspea~er 10 further
24 includes a cylindxically shaped voice coil member 20 which
is mecha~ically coupled to the base peripheral edge 1~ of
26 ~he diaphragm 12, a voice coi~ Zl disposed about the voice
27 coil member ~0, a:.ring shaped magnet 22, which is disposed
28 about the voice coil 21 and which is mechanically coupled
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1 to the back pla-te 18, and a cylindrical iron pole piece 23 which
is disposed within the voice coil member 20 and which is also
mechanically coupled to the back plate 18. The ring-shaped may-
net 22 and the pole piece 23 create a magnetic gap across the
voice coil 21.
Still referring to FIG. 2 the loudspeaker 10 still
further includes a centering spider 24 which mechanically couples
the base peripheral edge 16 of the diaphragm 12 to the base por-
tion 26 of the frame 17. The centering spider 24 centers the
1~ voice coil 21 within-the magnetic gap.
Referring now to FIG. 3 in conjunction with FIG~ 4 the
stabilizing spider 11 is mechanically coupled to the internal
sidewall 15 of the di~phragm 12 ~o a rod 25 which is disposed
perpendicularly to the pole piece 23 at th.e center thereof.
Referring briefly to FI~. 5 one may view a front plate
18 of the loudspeaker 10.
Referring again to ~IG. 3 the sta~iliæing spider 11 is
mechanically coupled to the rod 25 by a mounting device 30 which
is adapted to travel up and down the rod 25 and which is secured
in place by a set screw 31 to provide adjustability to the stab-
ilizing ~Pider. In operation the stabilizing spider 11 provides
a more truly axial movement while eliminating lateral movement
than the dual spider taught by Abraham B.. Cohen .in his articles.
The stahilizing spider 11 also functions as a dust cap.
Referring no~ to FIG. 6 a first coupling device 60 for
mechanically coupling the ~tabilizing spider 11 to the
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1 rod 25 includes a pair of disc-shaped members 61 between which
2 the stabilizing spider 11 is placed and which are joined by a
3 pair of set screws 62. The stabilizing spider 11 may be
4 radially adjusted. The coupling device 60 may be adapted for
traveling slideably along the rod 25 so that the stabilizing
6 spider 11 may be axially adjusted and is then secured by a
7 third set screw 63.
8 Referring now to FIG. 7 a second coupling device 70
9 for mechanically coupling the stabilizing spider 11 to a rod
`B 10 71 o~ a seeon~ type having a threaded portion 72~ The second
11 coupling device includes a top piece 73 and a bottom piece -~
12 which the stabilizing spider 11 i~ placed. The second
13 coupling device 70 i.s adaptad to be mechanically coupled to
14 the threaded portion 72 of the rod 71 so that the stabili2ing
spider 11 may be adjusted axially along the rod 71.
16 Referri~g now to ~IG. 8 the stabilizing spider 11 may
17 be mechanicall~ coupled to a rod 81 whlch is secured to a
18 support mem~er 82 which is at~ached t:o oppositely disposed
19 peripheral edges o the ~rame 17 o~ the loudspeaker 10. The
stabilizing spider 11 i5 mechanically coupled ~o the rod 81
21 by the second coupling device 70.
22 Referring now to FIG. 9 the stabilizing spider 11
23 may be mechanically coupled to a mass 90 which has a central
24 hole 91 therein and slideably coupled to the rod 25 so that
the stabilizing spider 11 is axially aligned and centered.
26 The mass 90 provides additional mass which may be adjusted
27 in addition to the compliance of the stabilizing spi~er 11
28 in order to alter the mechanical-acoustical sys~em of the
.
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1 loudspeaker 10. There is also a cylindrical~Teflo~ bearing
2 92 to provide slideability for the mass 90 disposed within
3 the hole 91 thereof.
4 Furthermore, it should be noted that the schematics
of the device have not been drawn to scale and that distances
6 of and between the figures are not to be considered signifi-
7 cant.
8 Accordingly, it is intended that the foregoing
9 disclosure and showings made in the drawing shall be considered
as illustrations of the principles of the present inventi~n~
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