EXTENSION PLUG-IN UNIT

Abstract: An extension plug-in unit comprising a female connector (2) coupled to a first cable (1) and a male connector (4) coupled to a second cable (3), which connectors (2, 4) comprise contacts arranged to establish an electrical connection, the connectors forming a hinge joint when connected together. The invention is characterized in that both the contacts (8) of the female connector (2) and the contacts (7) of the male connector (4) are flexibly attached to the surfaces of the female connector (2) and the male connector (4) positioned opposite one another during the coupling of the connectors, wherefore it is possible to couple the contacts by pressing the connectors together by means of the hinge joint (12).

Description: EXTENSION PLUG-IN UNIT BACKGROUND OF THE INVENTION The invention relates to an extension plug-in unit comprising a female connector coupled to a first cable and a male connector coupled to a second cable, which connectors comprise contacts arranged to establish an electrical connection, the connectors forming a hinge joint when connected together. Electric cables are usually coupled by means of connectors that are cylindrical in shape. The cylindrical connectors are connected together by inserting them into each other such that corresponding contacts in the female connector and the male connector are pushed into each other, thus establishing an electrical connection between the cables to be coupled. Depending on the conditions of use, the connectors may be exposed to dirt, which makes it more difficult to couple the cylindrical connectors conventionally by inserting them into each other. Further, with cylindrical connectors it is difficult to set up an arrangement where a cable should be branched. The branching requires connections where an additional end with its connectors is branched off from the cable, and it is possible to further couple other units to this end. Such a branching arrangement is rather inflexible in practice and requires a great number of connectors. In an arrangement disclosed in Finnish Patent 92,266, the connectors of the extension plug-in unit are coupled by a hinge-type coupler. The connectors have the shape of a cylinder cut in two where contacts are provided on the cut surface. The hinge is formed at one end of the connectors to be coupled, such that when the connectors are pressed together around an axis of revolution formed by the hinge, the contacts produce an electrical connection. The problem with the extension plug-in units described above is especially how to form the contacts of the female connector in an advantageous and yet reliable manner. According to the prior art, the contacts of the female connector are formed of opposite contact sheets which are spring loaded in order to provide a reliable electrical connection and the compliance required for the coupling. Thus the contacts of the male connector are able to press between the opposite contact sheets of the female connector to form an electrical connection. The female contacts described above have a rather complicated structure and they are thus relatively expensive to manufacture. BRIEF DESCRIPTION OF THE INVENTION The purpose of the present invention is to provide an extension plug-in unit which avoids the aforementioned drawbacks and enables the coupling of cables in a more reliable manner and with a simpler connector structure than previously. This is achieved with an extension plug-in unit according to the invention, which is characterized in that both the contacts of the female connector and the contacts of the male connector are flexibly attached to the surfaces of the female connector and the male connector placed opposite one another during the coupling of the connectors, wherefore it is possible to couple the contacts by pressing the connectors together by means of the hinge joint. The extension plug-in unit according to the invention is based on the contacts of the connectors being flexibly supported on the connector surfaces. The contacts can thus be coupled by means of a hinge joint formed by the connectors. A primary advantage of the invention is that the coupling is reliable and that the preferred embodiment of the invention provides complete shielding from contact of the connectors, as well as easy coupling of the connectors. BRIEF DESCRIPTION OF THE FIGURES In the following, the invention will be described in greater detail in connection with preferred embodiments with reference to the accompanying drawings, in which Figure 1 is a cross-sectional view of a male connector in an extension plug-in unit according to the invention, Figure 2 is a cross-sectional view of a female connector according to the invention to be coupled to the male connector of Figure 1 , and Figure 3 shows an extension plug-in unit according to the invention. DETAILED DESCRIPTION OF THE INVENTION As shown in Figure 1 , connectors 2, 4 of the extension plug-in unit according to the invention comprise contacts 7,8 that are supported flexibly, according to the invention, on the surfaces of the connectors positioned one against the other during the coupling. The connectors are coupled by means of a hinge joint, which is formed when the connectors are attached together. During the coupling a hinge-like member 12 is formed near one end of the connectors and it is used to couple the connectors. The hinge joint is possible due to compliance provided in the contacts. When the connectors are coupled, the contacts that are supported flexibly on the connectors yield to a required extent towards the hinge joint, so that the male contacts are able to couple to the female contacts. In the embodiment shown in Figures 1 and 2, the contacts 7, 8 of the connectors are completely shielded from contact, which means that a contact pin 9 of the male connector and a contact recess 16 of the female connector are shielded by protective casings 10. In the embodiment disclosed herein, the compliance of the contacts is achieved by means of the protective casings of the contacts. The protective casings are attached to the connector frame, so that when the protective casings are made of a flexible material, the connectors are able to yield. The electrically conductive parts of the contacts, i.e. the contact pins and recesses, are attached to the ends of the protective casings to be fastened to the connector frame, so that the contact pins and recesses yield with their protective casings. In the embodiment shown in Figures 1 and 2, the protective casings of the contacts comprise several layers, which simultaneously provide shielding from contact and guide the contacts in the right direction during the coupling. A male contact comprises a cavity 13, which is arranged to receive the contact recess of the female contact during the coupling. The male contact also comprises an outer cylindrical cavity 14, which is arranged to receive the protective casing of the female connector. The protective casing of the male connector thus remains outside the protective casing of the female connector after the coupling. Due to the complete shielding from contact, the extension plug-in unit of the embodiment according to the invention is also applicable for use under very difficult conditions, such as in industrial surroundings. The extension plug-in unit according to the invention can be provided with a required number of contacts depending on the needs in each situation. In the embodiment shown in the figures, the connectors comprise five contacts, three of which may be phase contacts, for example, and one is a neutral contact and one is a protective earth contact. There may also be different types of contacts intended for signalling. In the connectors according to the invention, the coupling between the different contacts takes place in such an order that the contact that is closest to the hinge joint is coupled first and the other contacts are then coupled in order towards the other end of the connector. Therefore the connections that protect the cable, the possible load thereof and the rest of the network are preferably positioned closest to the end of the connector near the hinge joint. Such protective connections include a protective earth conductor and a neutral conductor. As shown in Figure 3, the extension plug-in unit may comprise a third cable 15 connected to one of the connectors and coupled directly through the connector 2. It is thus possible to couple in a simple manner, by means of the extension plug-in unit according to the invention, other units to a cable that is possibly already feeding another load. It is obvious for those skilled in the art that the basic idea of the invention can be implemented in various ways as the technology develops. The invention and the embodiments thereof are thus not restricted to the examples described above but they may vary within the scope of the claims.

Claims: CLAIMS 1. An extension plug-in unit comprising a female connector (2) coupled to a first cable (1) and a male connector (4) coupled to a second cable (3), which connectors (2, 4) comprise contacts (7, 8) arranged to establish an electrical connection, the connectors forming a hinge joint (12) when connected together, characterized in that both the contacts (8) of the female connector (2) and the contacts (7) of the male connector (4) are flexibly attached to the surfaces of the female connector (2) and the male connector (4) placed opposite one another during the coupling of the connectors, wherefore it is possible to couple the contacts by pressing the connectors together by means of the hinge joint (12). 2. An extension plug-in unit according to claim 1, characterized in that the contacts of both the male connector and the female connector (2, 4) are arranged inside protective casings (10), and the protective casing of a contact pin (9) in the male connector forms complete shielding from contact together with the protective casing of the contact (16) of the female connector. 3. An extension plug-in unit according to claim 1 or 2, characterized in that the protective casings (10) of the connector contacts are formed of a flexible insulating material and they are attached to the connector frame, such that the contacts (9, 16) provided inside the protective casings are fastened to the end of the casing connected to the connector frame (11).

Inventors: RANTANEN KARI, RANTANEN, KARI
Applicants: GRAND MARKET GLOBALIZERS OY, RANTANEN KARI, RANTANEN, KARI
Application year: 1999
Main classification: H01R13
IPC codes: H01R13