Surge protector assembly

A surge protector assembly which is easily, quickly and detachably installed in a main board of an electronic appliance for protection from instantaneous overvoltage is disclosed, the assembly has a surge relieving unit which absorbs instantaneous overvoltage in the event of a surge of voltage, a fuse connected to the surge relieving unit in series which cuts off power to the electronic elements in the event of an instantaneous overvoltage, a temperature indicator which varies in color in accordance with temperature of the assembly in order to allow a user to easily check whether the assembly is overheated or adversely affected by instantaneous overvoltage, and a plurality of lead terminals used for detachably attaching the assembly to the main board which enables a timely change of a damaged assembly with a new one.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates, in general, to a surge protector assembly 
used for protecting electronic appliances in the event of a surge of 
voltage and, more particularly, to a surge protector assembly suitable for 
being easily and quickly mounted or replaced with a new one and 
effectively protecting electronic appliances from instantaneous 
overvoltage caused by, for example, the striking of a lightning bolt. 
2. Description of the Prior Art 
In typical electronic appliances such as industrial or home appliances, 
various electronic elements such as choke coils, resistors, condensers and 
surge protectors are mounted on a printed circuit board (PCB) through a 
lead wire inserting and soldering process. That is, the electronic 
elements are preliminarily arranged on a PCB by inserting the lead wires 
of each element into the wire inserting holes of the PCB prior to 
soldering the lead wires onto the PCB. In this case, the mounting and 
soldering of the electronic elements onto the PCB may be achieved manually 
by a worker or automatically by robotic machinery. Of course, it should be 
understood that each of the electronic elements may be received in a case, 
which is screwed to the PCB or engages with a rail provided on the PCB. 
FIG. 11 is a sectional view showing a PCB with a varistor used as a surge 
protector. As shown in the drawing, the PCB 1 is printed with a wiring 
pattern (not shown) on the top side and has a plurality of lead wire 
insert holes. The lead wire 2a of the varistor 2 is inserted into a hole 
of the PCB 1 from the top side to the bottom side prior to soldering the 
lead wire 2a onto the bottom side of the PCB 1. In the drawing, the 
reference numeral 3 denotes a solder part formed on the bottom side of the 
PCB 1. Typically, various electronic elements are mounted onto the top 
side of the PCB 1 through a soldering process. In the operation of the 
PCB, one or more electronic elements on the PCB 1 may be adversely 
affected by overvoltage, overheating or electric shock and often requires 
replacement of the PCB 1 or replacement of the affected element with a new 
one. However, in order to replace an affected element with a new one, the 
affected element has to be removed from the PCB with the solder parts 3 
being thermally melted, thus requiring skilled and careful workmanship 
while replacing the affected element with a new one. Such a replacement of 
the electronic element is time consuming. In addition, the wiring pattern 
of the PCB 1 may be thermally affected while the solder parts 3 are heated 
and melted. In the above PCB 1 with the typical surge protector, it is 
also difficult to detect breakage or deterioration of the surge protector. 
Another problem of the above surge protector resides in that a thermally 
affected electronic element fails to be easily discriminated from other 
normal elements. 
In order to test the surge resisting performance of an electronic appliance 
with a varistor acting as a surge protector, it is necessary to remove the 
varistor from the appliance prior to testing and mount the varistor in the 
appliance through a soldering process after the testing, thus being time 
consuming. 
SUMMARY OF THE INVENTION 
Accordingly, the present invention has been made keeping in mind the above 
problems occurring in the prior art, and an object of the present 
invention is to provide a detachable surge protector assembly for 
electronic appliances, which allows a surge affected electronic element to 
be easily and quickly replaced with a new one and is easily removed from 
and mounted in an electronic appliance during a test of voltage resisting 
performance of the electronic appliance. 
Another object of the present invention is to provide a surge protector 
assembly, which allows a thermally affected electronic element to be 
easily discriminated from other normal elements. 
In order to accomplish the above objects, the present invention provides a 
surge protector assembly, comprising: a surge relieving unit adapted for 
absorbing instantaneous overvoltage applied to electronic elements in the 
event of a surge of voltage; a power cutoff unit connected to the surge 
relieving unit and adapted for cutting off power for the electronic 
elements in the event of an instantaneous overvoltage; a housing having a 
bottom cover and receiving both the surge relieving unit and the power 
cutoff unit; and a plurality of lead terminals connected to both the surge 
relieving unit and the power cutoff unit and set in the housing, with the 
lower end of each terminal projecting downward into the exterior of the 
bottom cover, the terminals being detachably attached to a main board thus 
detachably mounting the surge protector assembly onto the main board. 
In other embodiments of this invention, the surge protector assembly are 
formed into two types: an adapter-type assembly detachably mounted to the 
exterior wall of an electronic appliance and a socket-type assembly having 
a connector.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the embodiments of this invention, the same elements are designated by 
the same reference numerals and explanation is thus not deemed repeated. 
FIGS. 1 to 3 show a surge protector assembly, detachably mounted to a main 
board, in accordance with the primary embodiment of the present invention. 
In the primary embodiment, the surge protector assembly A, which protects 
a plurality of electronic elements mounted on a main board 10 from 
instantaneous overvoltage caused by a surge of voltage, comprises a surge 
relieving unit 11 and a power cutoff unit 12. The surge relieving unit 11 
absorbs instantaneous overvoltage applied to the main board 10 in the 
event of a surge of voltage, while the power cutoff unit 12 cuts off power 
for the electronic elements. The surge protector assembly also includes a 
plurality of lead terminals 13, which are connected to the lead wires of 
both the surge relieving unit 11 and the power cutoff unit 12. The 
detachable surge protector assembly A is mounted to the main board 10 by 
detachably inserting the lead terminals 13 into terminal insert holes 10a 
of the main board 10. 
In the present invention, a known surge protector is used as the surge 
relieving unit 11, while a temperature fuse, which is burnt out at a 
predetermined temperature, is used as the power cutoff unit 12. 
FIG. 1 is an exploded perspective view of the surge protector assembly 
according to the primary embodiment. As shown in the drawing, the surge 
relieving unit 11 is connected to the power cutoff unit 12 in series, with 
the lead terminals 13 being connected to the lead wires 11a and 12a of 
both the surge relieving unit 11 and the power cutoff unit 12. 
In order to protect the thermally affectable power cutoff unit 12, the lead 
terminals 13 are connected to the lead wires 11a and 12a through a 
non-heating process such as a clamping process in place of a heating 
process such as a soldering or welding process. In the preferred 
embodiment, the connection end of each lead terminal 13 is rolled thus 
forming a connection ring 13a at which the terminal 13 is connected to an 
associated lead wire 11a, 12a through such a non-heating process. Both the 
surge relieving unit 11 and the power cutoff unit 12, which are connected 
together in series, are arranged at a position between a box-shaped 
housing 14 and a bottom cover 15, with the lower end of each terminal 13 
projecting downward into the exterior of the bottom cover 15. In the 
preferred embodiment, the housing 14 opens at the bottom thus receiving 
both the surge relieving unit 11 and the power cutoff unit 12 therein and 
closed by a transparent window 14a at the top thus allowing a user to look 
at the units 11, 12 outside the housing 14. However, it should be 
understood that the housing 14 may be cast into a transparent body. In 
addition, the surge protector assembly also includes a temperature 
indicating means, which varies in color in accordance with temperature and 
allows a user to easily check whether the surge protector assembly A is 
overheated and adversely affected by instantaneous overvoltage caused by a 
surge of voltage. The temperature indicating means may comprise a 
temperature sensitive tape, which is attached to the external surface of 
the housing 14. Alternatively, the housing 14 may be painted with a 
temperature sensitive paint in place of the tape. At least one guide slot 
15a may be formed on each of the opposite edges of the bottom cover 15 
thus allowing the lead terminals 13 to pass through. The cover 15 is 
assembled with the housing 14 into a single body with the lead terminals 
13 passing through the guide slots 15a of the cover 15 so that the 
terminals 13 are easily set in the surge protector assembly A. 
When instantaneous overvoltage is applied to the main board 10 due to a 
surge of voltage, the voltage in the surge relieving unit 11 increases and 
causes the unit 11 to be overheated to a temperature of higher than a 
reference point and is thus damaged. When the surge relieving unit 11 is 
overheated as described above, the power cutoff unit 12 is burnt out, thus 
protecting both the electronic elements of the main board 10 and the 
electronic appliance from a fire caused by the damaged and overheated 
surge protector assembly A. At a temperature of higher than the reference 
point, the temperature indicating means of the surge protector assembly 
varies in color, thus allowing a user to easily check whether the assembly 
is overheated and damaged and to timely change the damaged assembly with a 
new one. 
When both the surge relieving unit 11 and the power cutoff unit 12 of the 
assembly A are adversely affected and damaged by instantaneous 
overvoltage, the two units 11 and 12 have to be changed with new units. In 
order to change the damaged units 11 and 12 with new units, the damaged 
assembly may be removed from the main board 10 prior to mounting a new 
assembly with normal units 11 and 12 onto the main board 10. 
Alternatively, the damaged assembly may be removed from the main board 10 
prior to removing the two damaged units 11 and 12 and the terminals 13 
from the housing 14. Thereafter, new units 11 and 12 and new terminals 13 
are assembled with the empty housing 14 thus forming a normal assembly 
prior to mounting the assembly onto the main board 10. 
The housing 14 of the assembly is closed by the transparent window 14a at 
the top thus allowing a user to look at the surge relieving unit 11 
outside the housing 14. 
In addition, a temperature sensitive tape 18 is attached to the interior 
wall of the housing 14 thus allowing a user to easily sense the 
temperature of the surge relieving unit 11. 
FIGS. 4 and 5 show a surge protector assembly in accordance with the second 
embodiment of the present invention. In the second embodiment, the surge 
protector assembly is formed into an adapter structure, which is not 
mounted to the main board 10 differently from the primary embodiment but 
is detachably mounted to the panel 22 of an electronic appliance. In the 
surge protector assembly A according to the second embodiment, both units 
11 and 12 are encased by a housing 14 free from any lead terminal 13. The 
housing 14 is assembled with a box shaped holder or socket 20 into a 
single body. The holder or socket 20 has both a stop flange at the top and 
two elastic clamp arms 19 at opposite outside walls, thus detachably 
holding the assembly A on the panel 22. That is, when the assembly A with 
the holder or socket 20 is fitted into a mounting slot of the panel 22 
from the outside, the elastic clamp arms 19 of the holder or socket 20 are 
pressed and in turn are elastically restored to their original positions, 
thus detachably clamping the assembly A to the panel 22. 
FIG. 6 is an exploded perspective view of an AC power socket or socket with 
the surge protector assembly A of this invention. As shown in the drawing, 
the assembly A with both the surge relieving unit 11 and the power cutoff 
unit 12 may be installed in an AC power socket or socket 21 with a 
connector. The AC power socket or socket 21 has two openings: a socket 
opening 23 and an assembly insert opening 24 which are formed abreast on 
the top of the socket 21. In the AC power socket or socket 21, a plurality 
of lead terminals 21a are provided in the socket opening 23, while the 
surge protector assembly A is received in the other opening 24. In this 
case, a plurality of contact holes 24a are formed on the bottom of the 
insert opening 24 and so the lead terminals 13 of the surge protector 
assembly A are inserted into the contact holes 24a. 
Each of the assemblies A, which are mounted to the panel 22 of an 
electronic appliance as shown in FIGS. 4 and 5 or installed in a power 
socket as shown in FIG. 6, effectively protects electronic elements from 
instantaneous overvoltage caused by a surge of voltage. 
FIGS. 7 and 8 show a lidded AC power socket 210 with both a fuse holder 25 
and the surge protector assembly A of this invention. In the drawings, the 
reference numeral 26 denotes a top lid, which covers the surge protector 
assembly A installed in the assembly insert opening of the socket 210. 
FIG. 9 is a sectional view of the surge protector assembly A of this 
invention, with a noise filter 30 being assembled with the surge protector 
assembly A. 
The surge protector assembly A according to any one of the embodiments of 
FIGS. 4 to 9 includes a temperature indicating means, which varies in 
color in accordance with temperature and allows a user to easily check 
whether the surge protector assembly A is overheated and adversely 
affected by instantaneous overvoltage caused by a surge of voltage. In the 
same manner as described for the primary embodiment, the temperature 
indicating means may be selected from a temperature sensitive tape or 
paint. Due to the temperature indicating means, it is possible to timely 
change a damaged assembly with a new one. 
FIG. 10a is a circuit diagram of a surge protector assembly according to an 
embodiment of this invention. As shown in the drawing, the surge protector 
unit 11 may comprise two varistors 11, with a common terminal of the two 
varistors 11 being grounded and the other end of each varistor 11 opposite 
to the common terminal being connected to a fuse or power cutoff means 12 
in series. 
In the assembly of FIG. 10a, a resistor may be connected to the two fuses 
12 at the ends opposite to the varistors 11. 
FIG. 10b is a circuit diagram of a surge protector assembly according to 
another embodiment of this invention. In the embodiment of FIG. 10b, the 
general construction of the assembly remains the same as that described 
for the embodiment of FIG. 10a, but a third varistor 11' is connected to 
the two varistors 11 in parallel at a position between each varistor 11 
and an associated fuse 12. In this embodiment, a resistor may be connected 
to the two fuses 12 at the ends opposite to the varistors 11. 
As described above, the present invention provides a surge protector 
assembly for electronic appliances. The assembly of this invention can be 
easily, quickly and detachably installed in an electronic appliance 
without damaging a main board or other electronic elements. The assembly 
also includes a temperature indicating means, which varies in color in 
accordance with temperature and allows a user to easily check whether the 
assembly is overheated and adversely affected by instantaneous overvoltage 
caused by a surge of voltage. Due to the temperature indicating means, it 
is possible to timely change a damaged assembly with a new one. The 
assembly thus effectively protects an electronic appliance from 
instantaneous overvoltage and lengthens the expected life span of the 
electronic appliance. 
Although the preferred embodiments of the present invention have been 
disclosed for illustrative purposes, those skilled in the art will 
appreciate that various modifications, additions and substitutions are 
possible, without departing from the scope and spirit of the invention as 
disclosed in the accompanying claims.