Connectors became indispensable parts used for connections in wiring of electrical and electronic equipment used in cars and other applications. Generally such connectors are held together due to the friction between connected contacts and housings, however, the shortcoming of the connections with retention based on friction is that they can not withstand vibration and other impacts, which can lead to their separation.
Therefore, a number of designs was suggested regarding connectors able to withstand vibrations. Among them, there are connectors with latching devices locking in the state of complete connection that prevent their separation due to vibration.
However, since the contacts of the connectors start to form electrical contact before the state of complete connection is achieved, it is possible to make electrical connection without completely joining the housings.
In the manufacturing process, the judgment concerning the state of the connection of the housings is made by visual observation of the state of the latching device or by existence of electrical connections between the wires. However, electrical connection often exists even at an incomplete joining of the housings. Visual observation of the latching devices also can produce erroneous judgment, due to the observation angle or a human error. These factors impart reliability of connectors.
In recent years, requirements to the reliability of electrical connectors have sharply increased, especially in relation to a wide use of such safety devices as air bag systems and anti-lock brake systems, etc. Therefore, the problem of an easy confirmation of a complete joining of the connector became especially important. A number of designs of connectors were offered making it possible to easily confirm complete joining.
For example, in the connector described in Japanese Utility Publication No. (1992)-3419, an electrical detection device was proposed. In this connector, an active latching device (or a passive latching device) of one connector housing produces an open or a closed electrical contact; when the passive latching device (or an active latching device) of the other connector housing comes against the active latching device (or a passive latching device) of the first connector housing, it switches the condition of the electrical contact to opposite, thus making it possible to confirm connection.
In the Japanese Patent No. (1985)-1774, one connector housing has a built-in indicating rod movable in the direction of the joining of the housings. When this connector housing is joined with the matching connector housing, a part of that connector housing pushes the indicating rod which sticks out of the housing by the length required for the connection.
However, the above mentioned connectors equipped with opening and closing electrical contacts are very complicated and expensive to produce. They also require a special detecting circuit, thus making the price of the entire system prohibitively high.
The disadvantage of the connectors equipped with the indicating rod is the fact that the length of the exposed portion changes gradually, which may easily end in an erroneous human judgment regarding the state of connection. It also can be used in applications where the connector is out of the vision field of the assembly worker.
This invention was made with the purpose to offer low-cost and simple design connectors in which the above disadvantages are corrected, making it possible to make judgment on the state of connection based on direct visual observation or by touch.