Electrical audio signal processing systems and devices – Electro-acoustic audio transducer – Electromagnetic
Reexamination Certificate
2001-04-19
2004-09-21
Le, Huyen (Department: 2643)
Electrical audio signal processing systems and devices
Electro-acoustic audio transducer
Electromagnetic
C381S396000, C381S410000, C381S395000, C381S412000, C340S388100
Reexamination Certificate
active
06795563
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a speaker for generating sounds by vibrating a vibration plate by an electromagnet, and more particularly to an electrodynamic speaker mounted on a printed circuit board of an electronic instrument such as a portable telephone.
In recent years, there is a tendency to mount small electric parts on a printed circuit board, electrodynamic speaker for the small electronic instrument is accordingly mounted on the printed circuit board. Such a printed circuit for the portable telephone is used as a signaling device.
Referring to
FIGS. 5 and 6
, which are a plan view of a conventional electrodynamic speaker and a sectional view taken along a line VI—VI of
FIG. 5
respectively, electrodynamic speaker
50
has a circular frame
51
having a central circular hole
51
b
and a cubic portion
51
a
. An annular shoulder
51
c
is formed on the frame
51
and a pair of cylindrical holes
51
d
are formed in the cubic portion
51
a
. A plurality of perforations
51
e
are formed in the frame
51
.
A yoke
52
made of magnetic material and having a dish-shape is secured to the wall of the central hole
51
b
. A disk-shape magnet
53
is secured on the yoke
52
and a disk-shape top plate
54
is securely mounted on the magnet
53
. Thus, a magnetic circuit is formed between the yoke
52
and the top plate
54
, interposing the magnet
53
.
An annular vibrating plate
55
made of plastic has a spherical central portion, a circular recess
55
a
at the periphery of the central portion and a peripheral portion
55
b
. An annular voice coil
56
is fixed to the underside of the recess
55
b
and inserted in the gap between the periphery of the top plate
54
and an upper portion of the yoke
52
.
A pair of lead plates
57
, each of which is made of an elongated metal plate, are embedded in the frame
51
. Each of the lead plates
57
is extended between a side wall of the cubic portion
51
a
and an end
57
a
exposed in the underside of the frame
51
. A coil spring
58
is inserted in each hole
51
d
. An upper end
58
a
(
FIG. 7
a
) of the coil spring
58
is inserted in a hole
57
c
formed in an end portion
57
b
of the lead plate
57
and electrically connected to the lead plate
57
by solder
65
(
FIG. 7
b
). The lower end of the spring
58
is projected from the underside of the frame
51
.
Both ends of the coil
56
are soldered to ends
57
a
of lead plates
57
. Thus, the coil
56
is connected to the coil springs
58
.
A cover
59
has sound emanating holes
59
a
and is adhered to the shoulder
51
c.
Here, it is necessary to accurately assemble the coil spring
58
in the hole
51
d
so as not to contact with the inner wall of the hole
51
d
.
FIGS. 7
a
and
7
b
are sectional views showing a method for assembling the coil spring. A positioning jig
90
is provided for positioning the frame
51
. The positioning jig
90
has a pair of positioning holes, each comprising a spring positioning hole
90
a.
In the assembling of the coil spring
58
, the frame
51
is mounted on the jig
90
as shown in
FIG. 7
a
. The coil spring
58
is inserted in the spring positioning hole
90
a
of the jig
90
and the hole
51
d
of the frame
51
. The upper end
58
a
of the coil spring
58
is inserted in the hole
57
c
of the end portion
57
b
of the lead plate
57
and the coil spring is compressed by a pressing jig
91
. The upper end
58
a
of the coil spring
58
is connected to the end portion
57
b
by the solder
65
as shown in
FIG. 7
b.
Referring to
FIG. 8
, the frame
50
is mounted on a printed circuit board
81
. The end of the coil spring
58
is pressed against a terminal on the circuit board
81
so that the electric current is applied to the coil
56
to vibrate the vibrating plate
55
. The generated sound is emanated from the sound emanating hole
59
a.
FIG. 9
is a sectional view showing a connecting portion of another conventional buzzer. A U-shaped connecting spring plate
62
is connected to a lead plate
61
secured to a case
60
of the speaker by solder
63
at an end thereof. Another end of the spring plate
62
is pressed against a terminal of a printed circuit board
82
.
When the case
60
is mounted on the circuit board
82
, the connecting spring plate
62
is bent and the end of the plate is contacted with a terminal of the circuit board
82
.
Therefore, if there is formed a gap between the case
60
and the circuit board
82
, the contact of the spring plate
62
with the terminal is kept.
FIG. 10
is a sectional view showing a further conventional connecting terminal device. A lead plate
71
is embedded in a speaker body
70
. A cord
72
is fixed to the lead plate
71
by solder
74
. A plug
73
is connected to the cord
72
and connected to a socket
75
on the circuit board
82
.
However, when each of the above described conventional sound generators falls and collides with a hard ground, the coil spring
59
or spring plate
62
disengages from the terminal. Furthermore, there must be provided a plurality of jigs for accurately soldering the coil spring or spring plate, which requires multiple manufacturing steps. In the case using the cord, it is necessary to provide expensive plug and socket.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a speaker having an external connecting terminal structure which has a high reliability and may be simply manufactured without accuracy jigs, and at a low cost.
According to the present invention, there is provided a speaker having a frame provided with a yoke, a magnet, a vibrating plate and a voice coil, and a pair of leads, wherein an end of each of the leads is connected to an end of the voice coil and the other end portion of the lead is secured to the frame and the underside of the other end portion is exposed, a terminal connecting device is provided for connecting the lead to an outside terminal, the terminal connecting device comprises a cylindrical case secured to the frame, a connecting rod slidably mounted in the cylindrical case, a coil spring provided in the cylindrical case to outwardly urge the connecting rod so as to be contacted with the outside terminal at an end of the connecting rod, and means for contacting the cylindrical case with the other end portion of the lead.
In an aspect of the invention, the means is engagement of a projection of the cylindrical case with a hole formed in the other end of the lead so as to keep the contact of the cylindrical case with the end of the lead.
In another aspect of the invention, the means comprises a ball provided in the cylindrical case so as to be outwardly urged by the coil spring to be contacted with an inside wall of a hole formed in the end of the lead.
The end of the connecting rod has a spherical shape.
The cylindrical case is secured in a hole formed in the frame in force fit engagement.
These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.
REFERENCES:
patent: 3774200 (1973-11-01), Heath
patent: 3950744 (1976-04-01), Stephens
patent: 5066235 (1991-11-01), Kobayashi
patent: 5287084 (1994-02-01), Sone
patent: 6023518 (1999-04-01), Kuwabara
patent: 6526152 (2001-01-01), Frasl
patent: 6476710 (2002-11-01), Togawa
Citizen Electronics Co. Ltd.
Dennison Schultz Dougherty & MacDonald
Harvey Dionne
Le Huyen
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