Electrical connectors – Having circuit interrupting provision effected by mating or...
Reexamination Certificate
2002-11-07
2004-09-21
Prasad, Chandrika (Department: 2839)
Electrical connectors
Having circuit interrupting provision effected by mating or...
C439S189000
Reexamination Certificate
active
06793510
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a protecting device and to a method for shutting off a power supply, and is designed to protect terminals by preventing arcs from being created between the terminals electrically disconnected when a power supply circuit in a relay block connected with a battery in an automotive vehicle is broken for maintenance or the like.
2. Description of the Related Art
The power supply from a battery should be shut off before conducting maintenance on various types of electrical equipment in an automotive vehicle, such as maintenance on a navigation system or a radio.
Batteries installed in a conventional passenger vehicle typically have been rated 12V or at maximum 14V. However, the number of electrical devices installed in automotive vehicles has increased recently and the amount of current supplied to each electrical device also has increased in recent years. Accordingly, high-voltage batteries of 36V to 200V have been proposed.
Safety considerations mandate shutting off the power supply from a high-voltage battery before conducting maintenance of electrical equipment with a power supply from a high-voltage battery.
In view of the above, a protecting device has been developed. The protecting device has a fixed member with a power supply connected circuit and a load-connected circuit. A protection plug is mounted detachably in the fixed member and has a power supply switching circuit for connecting the power supply connected circuit and the load-connected circuit. The fixed member may be accommodated in a relay block connected with a battery.
The power supply connected circuit and the load-connected circuit of the above-described protecting device are connected electrically by connecting a terminal of the circuit in the protection plug and a terminal of a circuit in an electrical connection box. The protection plug is detached from the fixed member to disconnect the terminals from each other for maintenance.
However, the use of a high-voltage battery creates the likelihood for an arc between the terminals when the protection plug is detached from the fixed member to disconnect the terminals. The arc can damage the terminals.
The invention was developed in view of the above problem and an object thereof is to prevent the creation of an arc between terminals when a protection plug is detached from a fixed member at the time of maintenance.
SUMMARY OF THE INVENTION
The invention is directed to a protecting device in which a protection plug or member for switching a power supply circuit is mounted detachably to a fixed member to connect a movable circuit in the protection plug and a fixed circuit of the fixed member and to form a power supply circuit for supplying a power to a load. The power supply circuit is broken by detaching the protection plug. An input contact portion, a temporal circuit contact portion and an output circuit portion are provided between a terminal in the movable circuit of the protection plug and a terminal in the fixed circuit of the fixed member. The input contact portion and the output contact portion are closed or electrically turned on to supply power to the load and the temporal circuit contact portion is opened or electrically turned off in a normal state where the protection plug is mounted to the fixed member. The temporal circuit contact portion is closed or electrically turned on and connected with the power supply circuit with the input and output contact portions closed or electrically turned on at a first stage during the detachment of the protection plug. Either one of the input and output contact portions is opened or electrically turned off at a second stage. The temporal circuit contact portion is opened or electrically turned off at a third stage, and the other of the input and output contacts is opened or electrically turned off at a fourth stage.
The temporal circuit contact portion is off in the normal state where the protection plug is mounted to the fixed member of the above-described protecting device to prevent the creation of an arc when the power supply circuit is broken. The temporal circuit contact portion is temporarily turned on when the power supply circuit is broken by detaching or manipulating the protection plug. Thus, no arc is created between the terminals when the input and output contacts of the power supply circuit are separated.
Specifically, the temporal circuit contact is closed (or electrically turned on) with both input and output contacts closed, thereby connecting with a power supply side circuit and/or a load side circuit of the fixed circuit via the temporal circuit. The power supply and the load are connected via the temporal circuit when the input contact of the power supply side circuit or the output contact of the load side circuit connected with the temporal circuit is opened (turned off) at the second stage. This can prevent an arc from being created between the terminals to be disconnected.
The temporal circuit contact is opened or electrically turned off after the input contact or the output contact is turned off. At this time, there is a possibility of creating an arc between the fixed terminal for temporal circuit of the fixed member and the movable terminal for temporal circuit of the protection plug forming the temporal circuit contact portion since these two terminals are disconnected in an electrically conductive state. However, the temporal circuit contact preferably is made of an arc resistant material. Thus, the terminals at the temporal circuit contact portion are unlikely to be damaged even if an arc is created. Even if they should be damaged, it does not present a big problem as compared to a case where the terminals at the output and input contact portions are damaged as these terminals are not intended for power conduction in a normal state.
One of the input and output contact portions is opened or electrically turned off to separate the terminals after the temporal circuit contact portion is turned off. At this time, the temporal circuit contact portion is already off and the other of the input and output contact portions is already off and, hence, the fixed circuit and the movable circuit are electrically disconnected, i.e. no current flows between these two circuits. Therefore, there is no danger of creating an arc between the terminals being disconnected to damage the terminals.
The terminals at the input and output contact portions, which are closed (or electrically turned on) in the normal state to form the power supply circuit, are not damaged. Thus, the electrical connection reliability of the power supply circuit can be improved.
One and the other of a movable terminal for temporal circuit of the protection plug and a fixed terminal for temporal circuit of the fixed member forming the temporal circuit contact portion may have a first contact comprising a long protuberance that is long substantially along a detachment direction of the protection plug and a second contact comprising a small protuberance.
Preferably, the first and second contacts are separated or electrically turned off in the normal state where the protection plug is mounted to the fixed member and are brought into sliding contact with each other during the detachment of the protection plug to enable a control of on-off periods.
One and the other of a movable terminal for temporal circuit of the protection plug and a fixed terminal for temporal circuit of the fixed member forming the temporal circuit contact portion preferably have a first contact made of a vertically long protuberance and a second contact made of a small protuberance. The first and second contacts are separated or electrically turned off in the normal state where the protection plug is mounted in the fixed member and are brought into sliding contact with each other during the detachment of the protection plug, thereby enabling a control of on-off periods.
A fixed terminal for temporal circuit of the fixed member forming the temporal circuit contact portion may comprise a sprin
Yamakawa Shuji
Yuasa Eriko
Casella Anthony J.
Hespos Gerald E.
Prasad Chandrika
Sumitomo Wiring Systems Ltd.
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