Electricity: circuit makers and breakers – Solid contact – Push button operated
Reexamination Certificate
2000-11-20
2002-05-07
Donovan, Lincoln (Department: 2832)
Electricity: circuit makers and breakers
Solid contact
Push button operated
C200S437000, C200S0060BA, C200S329000
Reexamination Certificate
active
06384358
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a small-sized direct current switch which is appropriate for use in a portable electric drill or any other electric-powered tool, and particularly to such a small-sized direct current switch which requires the quick turning-off and slow turning-on.
2. Related Arts
If an electric-powered tool is loaded heavily, and if its direct current switch turns off slowly, the electric arc will appear an elongated length of time between the stationary and movable contacts of the circuit, thus causing the contacts to be melted in short time.
It is liable that the movable and stationary contacts are melted together as a whole, thus allowing the drill or cutter to continue to rotate in dangerous condition. To prevent such danger, it is necessary that the switch be made to turn off quickly, thereby suppressing the appearance of arc between the movable and stationary contacts.
If the switch is so designed that the movable contact may leave the stationary contact quickly in the instant of switching off, the movable contact will be driven toward the stationary contact at such an increased speed that the so accelerated movable contact may bounce repeatedly on the stationary contact in the instant of switching on. This will cause electric arcs to appear an elongated length of time between the movable and stationary contacts, thus expediting the wear and deformation of the movable and stationary contacts.
In an attempt to obviate such problem, it has been proposed that dielectric current switches be designed so as to be capable of switching off quickly and switching on slowly, so that the life of the switch may extend.
Referring to
FIG. 12
, in such a conventional seesaw type of dielectric current switch a common pointed terminal
1
has its ridge
1
a
as a fulcrum for supporting the seesaw-like plate
3
, which has movable contacts
3
a
and
3
b
formed on its opposite ends. An actuator
4
has a pusher
5
spring-biased toward the ridge of fulcrum
1
a.
The pusher
5
is pushed against the seesaw-like plate
3
, still allowing the actuator
4
to move the pusher
5
back and forth on the seesaw-like plate
3
. Two stationary contacts
2
a
and
2
b
are formed in confronting relation with the movable contacts
3
a
and
3
b.
One of the stationary contacts requires no anti-bounce means, and is hereinafter referred to as “pseudo” stationary contact
2
b.
Likewise, the counter movable contact is referred to as “pseudo” movable contact
3
b.
The actuator
4
has anti-bounce projection
6
formed on the side of the pseudo stationary and movable contacts
2
b
and
3
b.
The anti-bounce projection
6
permits the movable contact
3
a
to move toward the stationary contact
2
a
at a reduced speed.
Assume that the actuator
4
is moved back and forth, allowing the pusher
5
to move back and forth on the seesaw-like plate
3
. When the pusher
5
stands upright on the ridge of fulcrum
1
a
of the common terminal
1
, the seesaw-like plate
3
is balanced in the middle, and when the pusher
5
is on either side of the ridge of fulcrum
1
a,
the seesaw-like plate
3
is tilted accordingly so that the movable contact on the descending end may be put in contact with the counter stationary contact.
Assume that the pusher
5
traverses the ridge of fulcrum
1
a
from the left to right side, and that the seesaw-like plate
3
turns clockwise. Then, the seesaw-like plate
3
abuts on the anti-bounce projection
6
of the actuator
4
to retard its quick turn. Specifically in spite of traversing the ridge of fulcrum
1
a
of the common terminal
1
the pusher
4
cannot continue to turn the seesaw-like plate
3
still more.
The manual drive of the actuator
4
subsequent to abutment of the anti-bounce projection
6
against the seesaw-like plate
3
will displace the anti-bounce projection
6
rightward, so that the anti-bounce projection
6
may leave apart from the seesaw-like plate
3
. After the distance between the movable and stationary contacts
3
a
and
2
a
has been shortened, the movable contact
3
a
is driven and put on the stationary contact by the pusher
5
alone, requiring no manual push any more. Thus, the bounce can be eliminated.
Conversely assume that the pusher
5
traverses the ridge of fulcrum
1
a
from the right to left side, starting from the right end at which the movable contact
3
a
stays on the stationary contact
2
a,
and that the seesaw-like plate
3
starts turning counter-clockwise. Just prior to the pusher's traversing the ridge of fulcrum
1
a
the anti-bounce projection
6
abuts on the seesaw-like plate
3
. Thereafter, the force of the anti-bounce projection
6
to push down and turn the seesaw-like plate
3
counterclockwise about the ridge of fulcrum
1
a
increases so that it may be stronger than the pushing force of the pusher, thus forcedly departing the movable contact
3
a
from the stationary contact
2
a
even though they are melted and stacked together. After the pusher
5
traverses the ridge of fulcrum
1
a,
the movable contact
3
a
may be put apart from the stationary contact
2
a
by the pusher
5
alone.
FIG. 13
shows another conventional fast switching-off type of direct current switch. As shown in the drawing, a common terminal
9
has its pointed end
9
a
as a fulcrum for supporting the seesaw-like plate
8
, which has movable contacts
8
a
and
8
b
formed on its opposite ends. An actuator
11
has a pusher
12
loosely fitted in its recess. The pusher
12
is pushed downward with a spring
10
in the recess of the actuator
11
so that it may be raised and lowered in the recess, still remaining on the seesaw-like plate
8
while the actuator
11
moves horizontally. Thus, the seesaw-like plate
8
is allowed to turn clockwise or counter clockwise about its fulcrum. The seesaw-like plate
8
has a plateau
13
lying from the fulcrum
9
a
toward the right movable contact
8
a.
When the actuator
11
is pushed rightward by hand, the pusher
12
is moved rightward on the seesaw-like plate
8
, and it climes the plateau
13
, continuing to move rightward while turning the seesaw-like plate
8
clockwise about its pointed fulcrum
9
a.
Finally the movable contact
8
a
abuts on the stationary contact
7
a,
making an electric connection between the common terminal
9
and the stationary contact
7
a.
The climbing-up of the plateau
13
effectively retards the abutment of the movable contact
8
a
on the stationary contact
7
a,
thus attaining the slow switching-on of the seesaw type of switch.
Conversely when the actuator
11
is pushed leftward, the pusher
12
slides down quickly from the plateau
13
when traversing the fulcrum point
9
a,
thus allowing the seesaw-like plate
8
to turn counter-clockwise about the fulcrum point
9
a.
Then, the spring
10
is allowed to extend the stepwise-distance or flight of the plateau
13
from the compressed condition in which the coil
10
was compressed by the pusher
12
remaining on the plateau
13
. The sliding-own of the pusher
12
is expedited by the releasing of the spring
12
to give a quick push to the seesaw-like plate
8
, thus attaining the quick switching-off of the seesaw-like switch.
As for the seesaw-like switch of
FIG. 12
, the switching-on can be satisfactorily retarded by the anti-bounce projection
6
. The beginning of the switching-off, however, depends on the manual movement of the anti-bounce projection
6
, and therefore, the switching-off is retarded, and is slower than that performed by the automatic seesaw action.
As for the seesaw-like switch of
FIG. 13
, disadvantageously the slowness in the retarded switching-on and the quickness in the expedited switching-off depend on the speed at which the actuator
11
is moved, and the bounce cannot be effectively prevented.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a direct current seesaw type of switch which is capable of effectively expediting the switching-off and retarding the switching-on of th
Donovan Lincoln
Lee Kyung S.
Rader & Fishman & Grauer, PLLC
Satori Electric Co., Ltd.
LandOfFree
Direct current switch capable of turning on slowly and off... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Direct current switch capable of turning on slowly and off..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Direct current switch capable of turning on slowly and off... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2822606