Overload protector structure of extension cord receptacle

Details Overload protector structure of extension cord receptacle Overload protector structure of extension cord receptacle

2001-05-23

2004-02-24

Toatley, Jr., Gregory J. (Department: 2836)

Electricity: electrical systems and devices

Safety and protection of systems and devices

Circuit interruption by thermal sensing

C337S068000

Reexamination Certificate

active

06697246

ABSTRACT:

BACKGROUND OF THE INVENTION
1) Field of the Invention
The present invention relates to an overload protector structure of an extension cord receptacle, more especially an overload protector structure that simplifies the joint point structure of an overload protector and provides a simple connecting method to enable the overload protector to be rapidly assembled in the extension cord receptacle and to reduce the number of the soldering joint points.
2) Description of the Prior Art
Accordingly, seat bodies of available extension cord receptacles usually provide multiple receptacles for plugging the plugs (some extension cord receptacles have additional switches for controlling the on/off of the power). That not only effectively extends the supply of the power, but also divides the original single receptacle into multiple receptacles so that the power can be supplied to more electrical products. However, too many plugs plugged together in one extension cord receptacle might inevitably increase the load of the extension cord receptacle and tend to over load the current. Hence, some extension cord receptacles have an overload protector disposed in the structure thereof. Once the current for using on the extension cord receptacle exceeds the preset value and cases the temperature of the circuit to rise, the said overload protector can break off the circuit automatically and cut off the power supply to avoid danger. When the operating temperature of the extension cord receptacle recovers to the normal value, the overload protector can connect the circuit for normal operation automatically again. The allocation of the overload protectors of most of the available extension cord receptacles is shown in
FIGS. 11 and 12
, wherein a receptacle (
91
) and a switch (
92
) are embedded in an upper housing member (
90
) of an extension cord receptacle (
9
) in order. An overload protector (
93
) is mounted at a distal end of a power line (
94
), the said overload protector (
93
) comprises a power input plate (
931
), a power output plate (
932
) and a press-button (
933
). In assembling, a fire wire (
941
) in a power line (
94
) is soldered to the power input plate (
931
) of the overload protector (
93
). A shortcut conducting wire (
95
) is soldered to the power output-plate (
932
) of the overload protector (
93
), the other end of the, said conducting wire (
95
) is soldered to a fire wire input end (
921
) of the switch (
92
). In addition, a ground wire (
942
) in the power line (
94
) is soldered directly to a ground wise end (
922
) of the switch (
92
). In operation, once the operating temperature exceeds the preset value the overload protector (
93
) will cut off the circuit automatically and the press-button (
933
) will be in an ejected state. After the operating temperature of the extension cord receptacle (
9
) recovers to the normal temperature, the press-button (
933
) can be depressed to resume and the overload protector (
9
) will conduct the circuit again. However, the mentioned conventional structure has at least the following disadvantages:
1. Since too many soldering joints are produced for disposing the overload protector (
93
), as shown in
FIG. 12
, four soldering joints (
99
A,
99
B,
99
C,
99
D) are required between the power line (
94
) as well as the overload protector (
93
) of the extension cord receptacle (
9
) and the switch (
92
). So many soldering points (
99
A,
99
B,
99
C,
99
D) not only increase the difficulty and time in assembling, but also make the QC (Quality Control) workers spend more time in inspecting all the soldering joints (
99
A,
99
B,
99
C,
99
D) one by one. And so many soldering joints (
99
A,
99
B,
99
C,
99
D) might increase the probability of defects of the product due to the imperfect soldering joints (
99
A,
99
B,
99
C,
99
D) and that is unfavorable for enhancing the good yield ratio of the product.
2. The overload protector (
93
) is presented as a separate unit linked with the switch (
92
) via the conducting line (
95
). Therefore the overload protector (
93
) occupies a certain space in the extension cord receptacle (
9
) and that is unfavorable for designing a light, thin, short and small extension cord receptacle (
9
).
3. The overload protector (
93
) is an independent component difficult to be further simplified with fixed components as well as assembly cost and is not a starting point for saving the manufacturing cost.
4. The overload protector (
93
) and the switch (
92
) are soldered to connect via the conducting line (
95
) and they might split to separate from each other.
SUMMARY OF THE INVENTION
The design of the present invention is to efficiently improve the mentioned disadvantages, mainly to simplify the joint point structure of the overload protector and provide an easy connection method for enabling the overload protector to be assembled rapidly in the extension cord receptacle and for reducing the number of the soldering joints. It is mainly to enable the fire wire conducting plate of the switch unit (or the receptacle unit) connected to the overload protector in the extension cord receptacle to extend properly. The overload protector has a housing member which is connected with the switch unit (or the receptacle unit). The overload protector has a power input plate exposed at the housing member thereof with a temperature sensing plate fixedly connected at an inner end of the power input plate. The other end of the temperature sensing plate is a free end with a contact point thereat. The said overload protector farther penetrates through a slot channel from the said contact point area, the fire wire conducting plate can fitly extend into the said slot channel for positioning and contacts with the contact point of the temperature sensing plate. The said temperature sensing plate contacts with the fire wire conducting plate in a normal state and will stick upward to bend and separate from the fire wire conducting plate when the current is overloaded. Thereby the connection between the overload protector and the switch can be simplified and faster and the soldering joints can be eliminated completely.
The present invention will be described in detail in conjunction with the drawings as follows.


REFERENCES:
patent: 4814739 (1989-03-01), Moldovan
patent: 5248954 (1993-09-01), Chiang
patent: 5526225 (1996-06-01), Wang
patent: 6229105 (2001-05-01), Huang

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