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Патент USA US2137780

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Nov'e 22, 1938.
Filed April 2o, 195e _
3 Sheets-Sheet l
Nov. 22, 1938.
Filed April 20, 1936
3 Sheets-Sheet
.0 Mo@ ¿my/M1.
Nov. 2.2, 1938.
Filed April 20, 1956 -
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3 Sheets-¿Sheet 3
Patented Nov. 22, 1938
Walter J. Paredes, Chicago, Ill., assigner to Arla
vox Manufacturing C‘ompany, a corporation of
Application April 20, 1936, Serial No. I75,442
6 Claims. (Cl. 179-115)
'I‘his invention relates to a speaker for radios
and the like, and more particularly to a speaker
having a permanent field.
One feature of this invention is that it provides
öV an effective field for the motor means, with a
small block of permanently magnetized material;
another feature of this invention is that the actu
ating means- for the .armature of the speaker
motor comprises a single loop of a relatively
10-` heavy strip of metal;`yet another feature of this
invention is that the actuating means also forms
the vsecondary of the energizing transformer, and
acts as a mounting therefor; yet another feature
of this invention is that a single straight‘lever,
15' rigidly mounted on the armature, forms the con
necting means between the armature and the dia
phragm of the speaker; a further feature of this
invention is that the connecting lever is so con
structed and arranged that a straight drive from
20` the armature to the diaphragm is effected, per
mitting compact mounting of the motor means
with relation to the rest of the speaker; another
feature of this invention is that the motor frame
is so constructed and arranged as to readily as
25 semble the various parts, and to make a single
unit of considerable structural strength, easily and
compactly mounted on the basket of the speaker;
still other features and advantages of this inven
tion will be apparent from the following specifica
30~ tion and the drawings, in which
l Fig. 1 is a top plan view of the speaker; Fig.
2 is a vertical elevation of the speaker from the
motor end; Fig. 3 is a fragmentary sectional view
along the line 3-3 of Fig. 1; Fig. 4 is a horizontal
35 sectional view along the line 4--`4 of Fig.` 2; Fig.
5 `is a vertical sectional View along the line 5-5
of Fig. 1; Fig. 6 is a vertical sectional view along
the line 6--6 of Fig. 1; Fig. '7 is a perspective view
ofthe ñeld elements and block of magnetized
40 material; Fig. 8 is a perspective View of the arma
ture and connecting lever; and Fig. 9 is4 an en
larged perspective view of the actuating coil.
The earlier speakers or mechanical-electrical
translating devices, used in the radio field for
45 transforming variable currents into audible sound
waves, were generally of 'the type wherein 'only
one magnetic field was employed and the variable
current varied this field to provide greater or
less attractive force on a metal diaphragm. More
50 recently, speakers have been almost exclusively
of the so-called‘dynamic type, wherein one field
is provided,` and an armature is placed therein,
and a second field is set up in said armature with
the variable currents to cause movement thereof.
55 Thismovement is then transferred by some me
chanical connecting means to the diaphragm, now
generally cone-shaped and of non-metallic ma
terial. Such speakers generally have a field de
veloped through the action of coils energized by
a relatively heavy direct current, and thus con- 5':
siderable drain exists on the power pack or bat
teries supplying the speaker field.
More recently, a magnet metal or material,
capable of about ten times the coercive force of
ordinary magnet steel, and which maintains its 10
magnetization substantially permanently, has
been developed.
This `material is an iron base
alloy, also containing nickel, aluminum and co
balt, which latter named metals form approxi
Vmately 25%, 15% and '7% of the total. With 15
this material, permanent magnet ñelds can be
made of sufficient strength to operate properly ln
the motor means of a speaker of the preferred
While this material, commercially available and 20
not further ‘described here, since it forms no part
of this invention, has high coercive force, it is
expensive, brittle, and not readily workable by
any means except grinding. 'I'he presentv inven
tion uses only a relatively small block of this 25
material, substantially cubical or somewhat recti
linear in shape, and provides the proper field flux
path through field elements of permeable lamina
tion, contacting each end of the block.
The current, delivered by the output tube of the 30
audio system of the usual receiver, is of compara
tively high volta-ge and low current, whereas the
armature of the speaker motor means is prefer
ably driven by a current of higher intensity.
Thus, step-down transformers are generally used, 35
and wherethese are separate from the speaker,
the relatively high current intensity from the
transformer secondary to the actuating coil of
the `speaker results in heat losses in the lead
wires. The speaker disclosed herein is an im- 40
provernent, in that the armature actuating coil '
and the transformer secondary are formed by a
single loop of relatively heavy metal of good con
ductivity, so that negligible heat losses result and
a very good transfer of energy is had. This coil 45
or strip, moreover, also serves as the mounting
for the transformer` and helps in making a com
pact unit.
In order to provide a direct drive from the
armature to the apex of the cone diaphragm, the 50
connecting lever is centrally ‘mounted in the
armature at right angles thereto >and passes
through an opening in one of the ñeld elements
provided by spacing apart two of the laminations
which make up such element. The lever arm is 55
also slotted or provided with an opening, which
surrounds one leg of the actuating coil, so that
strength is achieved without sacrifice of com
pactness and operating efliciency.
The motor frame is formed of two stampings
of brass, aluminum, or other non-magnetic ma
terial, and provided with slots adapted to receive the ends of the laminations of the field
elements. These slots, and spacing means, en
10 able an assembly, wherein the ñeld elements, mag
net block, armature, and actuating coil, are all
held in an assembled unit through the use of only
two rivets.
In the particular embodiment of this invention
15 disclosed herein, a frame or basket I0 has mounted
therein a diaphragm II, here shown as a cone.
Motor means I2 is also mounted on the basket
and is adapted to drive the cone diaphragm
through the lever I3, connected to the apex of
the cone II by the pin I4. 'I'he motor means I2
comprises a motor frame consisting of an upper
stamping I5 and a lower stamping I6, both being
of non-magnetic material, a field consisting of
field elements I‘I and I 8, and a block of mag
25 netized material I9, an actuating coil or strip
20, an armature 2|, the connecting lever I3, and
a transformer 22.
Considering the field in more detail, each field
element I‘I and I8 is composed of a number of
30k laminations of highly permeable material, each
lamination being substantially F-shaped. The
block I9 of permanently magnetized material is
either cubical or slightly elongated, and is adapt
ed to be engaged and grippingly held by the bot
35 toms or lower parts of the field elements depend
ing beneath the arms which direct the field
across the armature 2|. These upper and lower
arms are adapted to lie immediately adjacent
opposite sides of the armature, and to have the
40 actuating coil or strip 20 extend therethrough
between the upper and lower arms thereof.
By means of this construction, a strong per~
manent ñeld is developed across the armature at
the desired place by the use of a relatively small
45 block of the expensive permanently magnetized
The armature, best shown in Fig. 8, comprises
a series of laminations 23, end pieces 24, rivets
25, and L-shaped mounting brackets 26 of
springy metal. 'I'he lever I3 is rigidly mounted
in the center of the armature by the rivets 25,
and extends out at right angles thereto. This
lever is provided with a slot or opening 21 there
through, adapted to surround one leg of the actu
ating coil 20 to permit free play of the lever arm
asfthe armature rotates slightly as a result of
the spring in the mounting brackets 26.
The actuating coil 20, best shown in Fig. 9, is
provided with a substantially square opening 28
60 near one end thereof, and an elongated opening
29 near the other end thereof, these openings be
ing joined by the slot 30. The opening 28 is
adapted to have the central leg 3|, or core of the
transformer 22, pass therethrough, so that the
65 primary coil 32 of the transformer is in sub
stantial registry with this opening, and this end
of the coil 28 acts as the secondary of the trans
former. The other opening 29 is adapted to sur
round the armature 2l and to set yup a varying
flux therethrough as a result of the variable cur
rent induced in the coil 20 by the transformer
22, and thus to drive the diaphragm I I of the
speaker. The coil 20 is preferably of a strip of
copper, shaped as shown,'and it acts not only as
the actuating coil for the armature, and the sec
ondary coil for the transformer, but also acts as
the lead therebetween, since the two are really
one integral loop or coil, and also as the mount
ing or supporting means for the transformer.
Referring more particularly to Figs. 1, 4 and
5, the assembly of the motor means will be seen.
The upper stamping or frame piece I5 is pro
vided with slots 33 and 34, having central strips
or bars 35 and 36 left in place. These slots are
adapted to receive the upper ends of the field 10
elements I 'I and I8, and similar slots in the lower
stamping I6 are adapted to have the bottoms or
lower legs of the field elements project there
through. These slots are so spaced that the bot
toms of the ñeld elements I 'I and I8 make a tight 15
gripping contact with the magnetized block I9.
The spacers, as 35, space apart two of the lamina
tions forming the field element I8 and make
a slot or opening 3l, through which the lever I3
projects. The upper and lower stampings I5
and I6 are drawn together adjacent the holes
for the rivets 38 and 39, and the spacing at this
point is accurately stamped. This is necessary,
in order that the rivets 38 and 39 will hold the
entire structure together with the brackets 26 25
tightly gripped therebetween, and the actuating
coil or strip 20 also tightly held between the
strips of insulation 40, provided to prevent elec
trical contact between the coil and the frame.
Thus, the entire motor means for the speaker is 30
held in operative assembly by the two rivets 38
and 39, and it is only necessary to mount the
frame on the basket,las by the bolts 4I, and then
solder or otherwise fasten the pin I4 to the
lever I3.
While I have shown and described certain
embodiments of my invention, it is to be under
stood that it is capable of many modifications.
Changes, therefore, in the construction and ar
rangement may be made without departing from 40
the spirit and scope of the invention as disclosed
in the appended claims, in which it is my inten
tion to claim all novelty inherent in my inven
tion as broadly as permissible, in view of the
prior art.
I claim:
1. Motor means for driving the diaphragm of
a speaker of the character described, including:
a movable armature of magnetic material; con
necting means between said armature and said 50
diaphragm; field elements of highly permeable
material adjacent opposite sides of said arma
ture and having substantially parallel portions
extending therefrom; a motor frame of non
magnetic material having slots therethrough,
said field elements having portions extending
through said slots; a relatively small block of
permanently magnetized material gripped be
tween the extending portions of said field ele
ments whereby a permanent field flux through 60
said armature is maintained; and means for set
ting up a second variable flux through said ar
2. Motor means for driving the diaphragm of
a speaker of the character described, including: 65
a movable armature of magnetic material; con
necting means between said armature and said
diaphragm; field elements adjacent opposite
sides of said armature and having substantially
parallel portions extending therefrom, said ele 70
ments comprising laminations of highly perme
able material; a relatively small block of perma
nently magnetized material between the extend
ing portions of said field elements, whereby a
permanent field flux through said armature is
maintained; a motor frame so constructed and
arranged that it supports saidV field elements and
causes them to grippingly support said block;
and means for setting up a second variable flux
through said armature, whereby movement of
said diaphragm is effected.
3. Apparatus of the character claimed in claim
2, wherein two of the laminations of one of said
ñeld elements are spaced apart to permit said
connecting means to pass therebetween, and said
block is magnetically parallel to said permanent
4. Motor means for driving the diaphragm of
a speaker of the character described, including:
a frame having slots therethrough; ñeld elen
ments having extended portions and at least
two arm portions substantially perpendicular to
said extended portions, the top and bottom of
each of said field elements projecting through
said slots; .a block of permanently magnetized
material grippingly supported by the extending
portions of said field members, whereby a mag
netic ñeld exists between the arm portions of
said ñeld members; an armature in said field; a
lever having one end rigidly mounted on said ar
mature and the other end connected to said
diaphragm; and means for setting up a second
variable flux through said armature, whereby ,
movement of said diaphragm is effected.
5. Apparatus of the character claimed in claim
4, wherein said lever passes between spaced
laminations in one of said ñeld elements.
6. Apparatus of the character claimed in claim
4, wherein the block is so arranged that the flux
therethrough is parallel to that of said field.
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