Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Plural independently operable switches
Reexamination Certificate
2000-10-25
2004-08-03
Barrera, Ramon M. (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Plural independently operable switches
C335S078000, C335S083000, C335S136000, C335S162000
Reexamination Certificate
active
06771154
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electromagnetic relay for use in activating and controlling a direct current (DC) motor for driving a windshield wiper drive section or a power window drive section of automobiles, for example.
2. Description of the Prior Art
Heretofore, DC motor drive circuits using an electromagnetic relay have often been used in order to activate and control a windshield wiper drive section and a power window drive section of automobiles.
FIG. 1
of the accompanying drawings is a schematic circuit diagram showing an example of a prior-art DC motor drive circuit for use in a windshield wiper drive section.
FIG. 2
is a schematic circuit diagram showing an example of a prior-art DC motor drive circuit for use in a power window drive section.
First, an example of the DC motor drive circuit for use in the windshield wiper drive section will be described with reference to. FIG.
1
.
As shown in
FIG. 1
, one end of a windshield wiper driving DC motor
1
is connected to a terminal
2
a
connected to a movable contact (this movable contact is usually connected to a suitable means such as a contact spring driven by an armature) AR of an electromagnetic relay
2
. The above terminal
2
a
connected to the movable contact AR will hereinafter be referred to as a “movable contact terminal”.
The other end of the DC motor
1
is connected to a terminal
2
b
connected to a normally closed contact N/C (i.e. break contact) of the electromagnetic relay
2
. The above terminal
2
b
connected to the normally closed contact N/C will hereinafter be referred to as a “normally closed contact terminal”. A connection point
2
d
between the other end of the DC motor
1
and the normally closed contact
2
b
is connected to the ground.
A terminal
2
m
connected to a normally open contact N/O (i.e. make contact) of the electromagnetic relay
2
is connected to a power supply at a terminal
3
, at which a positive DC voltage (+B) is supplied from a car battery. The above terminal
2
m
to which the normally open contact N/O is connected will hereinafter be referred to as a “normally open contact terminal”.
The electromagnetic relay
2
includes a coil
2
C. The coil
2
C is energized or de-energized by control current supplied from a windshield wiper drive controller
4
when a user operates a windshield wiper switch
5
. This windshield wiper switch
5
includes three fixed contacts
5
a
,
5
b
,
5
c
and a movable contact
5
m.
When the windshield wiper switch
5
connects the movable contact
5
m
to the fixed contact
5
a
(“OFF” position), the coil
2
C is not energized by controlling current from the windshield wiper drive controller
4
so that the electromagnetic relay
2
connects the movable contact AR to the normally closed contact N/C. As a result, one end and the other end of the DC motor
1
are connected to each other and thereby the DC motor
1
can be braked (or placed in the stationary state).
When the windshield wiper switch
5
connects the movable contact
5
m
to the fixed contact
5
b
(“INTERMITTENT” position), the coil
2
C of the electromagnetic relay
2
is intermittently energized by the controlling current from the windshield wiper drive controller
4
. As a result, the electromagnetic relay
2
connects the movable contact AR to the normally open contact N/O while the coil
2
C is being energized by the control current. When the coil
2
C is not energized by the control current, the electromagnetic relay
2
connects the movable contact AR to the normally closed contact N/C. Specifically, the electromagnetic relay
2
alternately connects the movable contact AR to the normally closed contact N/C and the normally open contact N/O each time the coil
2
C is energized or is not energized.
When the electromagnetic relay
2
connects the movable contact AR to the normally open contact N/O, direct current flows through the DC motor
1
as shown by a solid-line arrow I in FIG.
1
and thereby the DC motor
1
can be driven. When the electromagnetic relay
2
connects the movable contact AR to the normally closed contact N/C, the supply of the direct current I to the DC motor
1
is interrupted and the DC motor
1
becomes a generator of direct current so that direct current flows through the DC motor
1
in the direction opposite to that of the direct current I and the DC motor
1
can be braked, i.e. the DC motor
1
can be driven intermittently. As this DC motor
1
is driven intermittently, the windshield wiper is driven intermittently.
When the windshield wiper switch
5
connects the movable contact
5
m
to the fixed contact
5
c
(“CONTINUOUS” position), the coil
2
C of the electromagnetic relay
2
is continuously energized by the controlling current from the windshield wiper drive controller
4
. As a result, the electromagnetic relay
2
connects the movable contact AR to the normally open contact N/O to permit the direct current to flow through the DC motor
1
continuously as shown by the solid-line arrow I in FIG.
1
. Therefore, the windshield wiper can be driven continuously.
When the windshield wiper switch
5
connects the movable contact
5
m
to the fixed contact
5
a
(“OFF” position), the coil
2
C of the electromagnetic relay
2
is not energized so that the electromagnetic relay
2
connects the movable contact AR to the normally closed contact N/C. Therefore, the DC motor
1
becomes a direct current generator to allow current to flow through the DC motor
1
in the direction opposite to the direction in which the direct current flows as shown by the solid-line arrow I in FIG.
1
. Thus, the DC motor
1
can be braked and stopped.
Next, an example of a conventional DC motor drive circuit for use in a power window drive section will be described next with reference to FIG.
2
.
Referring to
FIG. 2
, one end of a power window DC motor
11
is connected to a movable contact terminal
12
a
of an electromagnetic relay
12
that can move the power window upward. The other end of the DC motor
11
is connected to a movable contact terminal
13
a
of an electromagnetic relay
13
that can move the power window downward.
A normally closed contact terminal
12
b
of the electromagnetic relay
12
and a normally closed contact terminal
13
b
of the electromagnetic relay
13
are connected to each other. A connection point
12
d
between the normally closed contact terminal
12
b
and the normally closed contact terminal
13
b
is connected to the ground. A normally open contact terminal
12
m
of the electromagnetic relay
12
and a normally open contact terminal
13
m
of the electromagnetic relay
13
are connected to each other. A connection point
12
e
between the normally open contact terminal
12
m
and the normally open contact terminal
13
m
is connected to the power supply at the terminal
3
, at which a positive DC voltage (+B) is connected from a car battery, for example.
The coil
12
C of the electromagnetic relay
12
is energized by controlling current supplied from a power window ascending controller
14
when a user operates the power window drive section to move the power window upward. The coil
13
C of the electromagnetic relay
13
is energized by controlling current supplied from a power window descending controller
16
when the user operates the power window drive section to move the power window downward.
Specifically, while the user is operating the power window drive section to move the power window upward, a switch
15
is continuously energized so that the coil
12
C of the electromagnetic relay
12
is energized by the controlling current from the power window ascending controller
14
, permitting the electromagnetic relay
12
to connect the movable contact AR to the normally open contact N/O. Therefore, a DC current flows through the DC motor
11
in the direction shown by a solid-line arrow I
1
in FIG.
2
and thereby the DC motor
11
can be driven in the positive direction, for example. Therefore, the power window of the automobile can b
Funayama Hideo
Sato Hiromitsu
Barrera Ramon M.
Taiko Device, Ltd.
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