Electricity: circuit makers and breakers – Electric switch details – Actuators
Reexamination Certificate
2002-08-07
2004-01-20
Friedhofer, Michael (Department: 2832)
Electricity: circuit makers and breakers
Electric switch details
Actuators
C200S520000, C200S523000, C200S524000, C337S066000
Reexamination Certificate
active
06680449
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to electric switches and, more particularly, to a press button switch having a seesaw switching mechanism for switching the circuit between on/off positions.
2. Description of the Related Art
A variety of electric switches, including seesaw switches and press button switches are known.
FIG. 1
shows a press button switch
1
according to the prior art. This design uses a press button
11
to move a metal contact plate
12
between on/off positions. The metal contact plate
12
is pivoted to the end portion
15
of one terminal
14
by a hook plate
13
, and moved by the push button
11
to switch on/off contacts
17
and
18
subject to the effect of a spring plate
16
. This design is not suitable for high current application. For high current application, additional component parts must be added, resulting in complicated structure and high frequency of failure.
FIGS. 2A and 2B
show a seesaw switch
2
according to the prior art. This design of seesaw switch
2
uses a plank
21
to move a spring
23
controlled push rod
22
, causing the push rod
22
to push a metal contact plate
24
between on/off positions. This design of seesaw switch
2
is suitable for high current application.
FIG. 2C
is a sectional view of a seesaw switch
20
according to Taiwan patent publication no. 320355, which was issued to the present inventor. According to this design, turning the plank
201
leftwards or rightwards switches on/off the circuit. When an overcurrent occurred, the metal contact plate
202
automatically trips off.
FIGS.
3
A~
3
E show an overload protective press button switch according to Taiwan patent publication no. 458362. This structure of overload protective press button switch comprises a housing
31
, the housing
31
having a top opening
311
and two open chambers
313
and
314
separated by a partition plate
312
, a metal contact unit
33
installed in the housing
31
, a switching mechanism
35
, a press button assembly
32
, and a linkage
34
. The linkage
34
comprises a spring member
342
supported on the partition plate
312
, a press member
341
mounted on the spring member
342
, and a swivel holder
344
pivoted to the housing
31
. The swivel holder
344
has a guide hole
343
, which receives the press member
341
, and a positioning portion
345
connected to the switching mechanism
35
.
When pressed the press button assembly
32
, the press member
341
is forced downwards to compress the spring member
342
and to bias the swivel holder
344
, thereby causing the switching mechanism
35
to switch on the metal contact unit
33
. When switched on, the spring member
342
pushes the press member
341
back to the initial position. The upper part I of this overload protective press button switch is similar to the design of the aforesaid prior art press button switch. The lower part II of this overload protective press button switch is similar to the design of the aforesaid prior art seesaw switch. This design is similar to Yu's Taiwan utility model no. 83365 (equivalent to U.S. Pat. No. 5,262,748) with the exception of the additional press button assembly
32
. The swivel holder
344
is equivalent to Yu's seesaw plank. This structure of overload protective press button switch is complicated, resulting in high manufacturing cost and inconvenience of use. When the push button assembly
32
pressed to the position shown in
FIG. 3C
, and the swivel holder
344
is biased leftwards, the metal contact unit
33
is switched on. When the user released the hand from the push button assembly
32
, the push button assembly
32
is moved to the position shown in FIG.
3
D. Viewing from the outside, it shows no difference between the position of
3
B and the opposition of
3
D, therefore the user cannot know “on” or “off” status of the switch when viewed from the outside. For on/off indication, a complicated indicator circuit must be installed.
SUMMARY OF THE INVENTION
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a press button switch, which enables the user to know “on” or “off” status of the switch when viewed from the outside. It is another object of the present invention to provide a press button switch, which provides the advantages of a seesaw switch. It is still another object of the present invention to provide a press button switch, which is easy and inexpensive to manufacture. It is still another object of the present invention to provide a press button switch, which has indicator means to indicate on/off status. It is still another object of the present invention to provide a press button switch, which achieves the advantages of an overload protective type seesaw switch. It is still another object of the present invention to provide a press button switch, which can easily be reset when tripped off due to an overload. To achieve these and other objects and according to one aspect of the present invention, the press button switch comprises a spring-supported press button, and a push member pivoted to the spring-supported press button and controlled by the spring-supported press button to slide along two symmetrical endless sliding tracks and to switch the seesaw switching mechanism between on/off positions. According to another aspect of the present invention, the endless sliding tracks each have a top positioning point adapted for supporting the press button in “on” position, and a bottom positioning point adapted for supporting the press button in “off” position. Therefore, the user can know “on” or “off” status of the push button switch visually subject to the elevation of the push button. According to still another aspect of the present invention, the seesaw switching mechanism can be equipped with a metal contact plate that automatically trips off upon an overload.
REFERENCES:
patent: 3551867 (1970-12-01), Ingwersen
patent: 5532444 (1996-07-01), Bonrath et al.
patent: 6335500 (2002-01-01), Chi et al.
patent: 6417756 (2002-07-01), Yu
patent: 6483416 (2002-11-01), Yu
patent: 6504122 (2003-01-01), Yu
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