Electrical connectors – With insulation other than conductor sheath – Plural-contact coupling part
Reexamination Certificate
2002-04-17
2004-01-06
Gushi, Ross (Department: 2833)
Electrical connectors
With insulation other than conductor sheath
Plural-contact coupling part
C439S669000
Reexamination Certificate
active
06672906
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a jack device for connecting a headphone to be used on a passenger seat of an airplane, for example, in particular to the structure of contacting parts with a plug.
BACKGROUND OF THE TECHNOLOGY
In recent aircrafts, an entertainment system is installed to provide music and movie entertainment to passengers. In such a system, individual passengers can listen to selected music or movie audio through a headphone installed on each passenger seat.
In order to improve the sound quality of such an entertainment system, noise-reduction type headphones are increasingly used. A noise reduction type headphone is one in which a noise is cancelled with a sound having a phase opposite to that of the noise. Left and right sound signals as well as DC power are supplied to this type of headphones.
In this type of headphones, three single-head plugs each having plural (mainly two) plug poles are normally used. These plugs are inserted into a jack device provided on a passenger seat for connection. A passenger can listen to desired audio through this connection.
FIG. 10
is an external appearance of a jack device for a conventional headphone. As is illustrated in
FIG. 11
, the jack device comprises case
200
and cable
26
having a connecting member for connection with a central apparatus of an entertainment system. Case
200
comprises upper case
21
and lower case
22
and is provided with three jack sections (
23
,
24
,
25
). Of the three jack sections (
23
,
24
,
25
), jack section
23
is for supplying DC power, and the other two jack sections (
24
,
25
) are used for left and right sounds. A single-head plug having plural plug poles is inserted into the inlet port of a jack section to a predetermined position. With this, connection of the single-head plug with the jack section is performed. Cable
26
extends out from case
200
for connection with a central apparatus of an entertainment system.
Inside cases
21
,
22
of the jack device, substrates
27
,
28
,
29
are provided for each respective jack sections
23
,
24
, and
25
as illustrated in FIG.
11
. Each of substrates
27
,
28
,
29
is soldered to corresponding jack sections
23
,
24
,
25
. Lead wires contained in cable
26
are connected to each of the substrates
27
,
28
,
29
.
A single-head plug is inserted into each of the jack sections
23
,
24
,
25
as described earlier. Each of these plugs has plural plug poles in the direction of insertion.
Referring to FIG.
12
and FIG.
13
and taking jack section
23
as an example, a description will now be given below on the structure of jack section
23
and the plug to be inserted into it.
FIG. 12
shows the cross section of jack section
23
.
Jack section
23
for supplying DC power comprises:
a. base
34
having opening
34
a
for insertion of a plug;
b. movable contact piece
31
as a first contact piece with the plug;
c. grounding spring
30
as a second contact piece with the plug;
d. fixed piece
32
; and
e. hollow holder
33
for affixing movable contact piece
31
, grounding spring
30
, and fixed piece
32
.
The structure of the other jack sections
24
,
25
is approximately the same as the structure of jack section
23
for supplying DC power.
For example,
FIG. 13
is an illustration of a state in which single-head plug
50
has been inserted halfway into jack section
23
. Plug
50
has plural plug poles (two plug poles in
FIG. 13
) in the direction of insertion. As illustrated in
FIG. 13
, plug
50
comprises plug pole
54
as a first plug pole disposed at the front end of the plug, plug
52
as a second plug pole disposed adjacently to plug pole
54
, and insulating collar
56
between plug pole
54
and plug pole
52
.
When plug
50
is inserted into jack section
23
, plug pole
54
is first brought into contact with grounding spring
30
. As plug
50
is further inserted, plug pole
54
is brought into contact with movable contact piece
31
.
In conventional jack devices of this type, the spacing (DB in
FIG. 12
) between movable contact piece
31
and grounding spring
30
on the inlet side is relatively small. As a result, as illustrated in
FIG. 13
, there occurs a case where plug pole
54
on the front end of the plug is simultaneously brought into contact with movable contact piece
31
and grounding spring
30
in the middle of insertion of plug
50
, namely, a state in which plug
50
has been inserted halfway. In the event such simultaneous contact occurs, movable contact piece
31
and grounding spring
30
are short-circuited through plug pole
54
.
In such a case, if the jack section is one for supplying a relatively small current such as an audio current, no serious trouble is caused. However, if the jack section is for supplying DC power, the following difficulty will be caused.
Short circuit of contact pieces for DC power inside a jack device will cause an overcurrent in a DC power supply unit of a central apparatus of an entertainment system. The overcurrent may trigger a protection circuit in the central apparatus thus causing suspension of system operation, malfunction or a failure.
DISCLOSURE OF THE INVENTION
The present invention addresses the above-described problems and provides a structure in which plural con tact pieces will not short-circuit in the middle of insertion of a plug. It is an object of the present invention to prevent suspension of operation, malfunction, or failure of an apparatus that is directly or indirectly connected to a jack device.
The present invention provides a jack device into which a single-head plug having plural plug poles in the direction of insertion is inserted for connection, and which comprises:
a base having an opening for insertion of a plug;
a first contact piece that is brought into contact with a first plug pole disposed at the front end of the plug;
a second contact piece that is brought into contact with a second plug pole disposed adjacently to the first plug pole; where
the first and the second contact pieces are provided in the direction of plug insertion; and
the spacing between the plug-contacting portion of the first contact piece and the plug-contacting portion of the second contact piece is made approximately equal to or greater than the length in the direction of plug insertion of the first plug pole of the plug.
Also, a hollow holder to which the first and the second contact pieces are affixed has a notch. When a plug is inserted, the second contact piece is pushed down toward the notch. The notch makes it possible to make the outer dimensions of a jack device with the above structure equal to the outer dimensions of a conventional jack device.
According to the above-described structure, the spacing between the two contact pieces is greater than the length of the above first plug pole. Accordingly, there will not occur any case in which the two contact pieces are simultaneously brought into contact with the first plug pole provided at the front end of the plug. Consequently, the two contact pieces will not make a short circuit through the first plug pole in the middle of plug insertion. Also, the outer dimensions of a jack device with the above structure can be made equal to the outer dimensions of a conventional jack device while preventing short circuit of the two contact pieces. That is, the jack device of the present invention can be used for a conventional plug without changing its length.
REFERENCES:
patent: 3108843 (1963-10-01), Frantz
patent: 3166649 (1965-01-01), Frantz
patent: 4368941 (1983-01-01), Martin
patent: 4659167 (1987-04-01), Masuda
patent: 5522738 (1996-06-01), Lace
patent: 47-28913 (1972-11-01), None
patent: 54-12990 (1979-06-01), None
patent: 62-79377 (1987-05-01), None
patent: 63-6500 (1988-01-01), None
patent: 63-63985 (1988-04-01), None
patent: 5-69877 (1993-09-01), None
patent: 6-140106 (1994-05-01), None
Gushi Ross
Matsushita Electric - Industrial Co., Ltd.
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