TERMINAL ARRANGEMENT FOR USE IN A MULTIPLEX TRANSMISSION SYSTEM

Abstract: In a multiplex transmission terminal, a body (30) of the terminal is composed of a pair of case halves (30a,30b) coupled by hinges (19) so that both of the case halves (30a,30b) can be opened and closed. One or more connecting pins (15-18) are provided in the case halves (30a,30b) so as to project in a recess (26) formed in the body so that said connecting pins (15-18) can contact to conductors (1-4) clamped in the recess (26) of the cable body.

Description: The present invention generally relates to a multiplex terminal arrangement for a multidrop connection used in a multiplex transmission terminal for an industrial field or vehicle system. In particular, the present invention concerns a multiplex terminal having the features a) to c) of claim 1. Such a multiplex transmission terminal is described in US 4,555,158. The disclosed multiplex transmission terminal has all connecting members for connecting to conductors of a cable assembly arranged in one case half. All conductors of the two pairs of conductors have the same shape and are accommodated in a recess means formed in the other case half. When closing the two case halfes the connecting members penetrate insolation layers of the conductors of the cable assembly such that a contact between the connecting members and the corresponding conductors is made. The cable assembly to which the terminal is connectable consists of four conductors of the same shape. Therefore, high electromagnetic interference is generated between individual conductors of this cable assembly. Since the connecting members corresponding to the conductors of the cable assembly are arranged in one case half, the described terminal is unsuitable for connecting two conductors having a different shape or configuration of individual conductors with respect to eachother. The connection problem is particularly difficult when individual ones of the conductors are used for transmission of different kind of signals as is shown for example in Figure 1, illustrating an example of a multiplex transmission system using a multidrop connection system using a multidrop connection system. In Figure 1, 101 and 102 denote power transmission lines for supplying power to the terminals 105 and 106 and 103 and 104 denote data transmission lines for transmitting data information to the terminals 105 and 106. In the shown example, the respective terminals 105 and 106 are provided with actuators 107 and 108 such as an electric motor or display lamp which are activated by the data information in addition to various switches 109 and 110 for inputting the data information. In the prior art the power lines 101 and 102 and data lines 103 and 104 are connected to the respective terminals 105 and 106 by means of one or more seperate connectors. However, in the prior art, it has been necessary to connect each cable with the terminal in such a manner that after each cable and is processed, a connector is attached to the cable end, whereby the cable is connected to the terminal. Thus the work for connecting the terminal is very comlicated. Moreover, it is necessary to provide additional connectors in the terminal side for receiving the end connector of the cable. The object of the present invention is to provide a multiplex transmission terminal which can easily be mounted on a cable assembly and whose connecting ends can achieve a secure connection to a first and second pair of conductors of a cable assembly. The above object is solved by a multiplex transmission terminal comprising the features a) to d) of claim 1. An advantage of the present invention is in that the terminal can be mounted on the cable unit by only clamping operation and it is easy to have the connector pins contacted with the conductors of the cable unit without any works to the cable such as cable cutting and processing. Moreover, since no connector member is necessary on the cable side, the cost of connecting the terminal to the cable can be reduced. Another advantage of the present invention is that the terminal can be mounted anywhere desired in an easy manner. Further advantageous embodiments of the present invention are described in the dependent claims. In the following further advantages and embodiments of the present invention are described with reference to the attached drawings, in which: Fig. 1 is a circuit diagram showing an example of multiplex transmission terminal, Fig. 2 is a perspective view of an example of a multiplex transmission terminal according to the present invention, Fig. 3 is a perspective view showing an example of a cable used in the embodiment shown in Fig. 2, Fig. 4 is a front view of the multiplex transmission terminal shown in Fig. 2 with the case halves opened, Fig. 5 is a perspective view showing an example of the multiplex transmission terminal attached to a multiplex cable, and Fig. 6 is a perspective view of the multiplex transmission terminal attached to the multiplex cable. Referring to Fig. 3, there is shown a multiplex cable unit 10 used for the multiplex transmission terminal according to the present invention. The cable unit comprises a pair of power supply conductors 1 and 2 of an elongated strip shape extending parallelly, being opposed each other. The two conductors 1 and 2 are separated as close as possible but assuring a desired withstand voltage. To dispose both conductors 1 and 2 as close as possible enables to increase a capacitance between them, thereby to provide low impedance power supply lines. The cable unit further comprises a pair of signal conductors 3 and 4 closely disposed each other and extending parallelly at any one side of the power supply conductors 1 and 2. The respective distances between the signal conductor 3 and both of the power supply conductors 1 and 2 are made equal so as to prevent electrostatic induction from the power supply conductors 1 and 2. The respective distances between the signal conductor 4 and both of the power conductors 1 and 2 are also equal. The respective conductors 1 to 4 are covered with insulation material 11 (referred to as insulation layer hereinafter) as shown in Fig. 3. Although the conductors 1 to 4 are covered with insulation layer 11 over the whole length of the conductors, the terminal can be connected to the respective conductors 1 to 4 anywhere desired on the multiplex cable unit as mentioned below. Referring to Fig. 2, a terminal case body 30 is composed of a top case half 30a and bottom case half 30b made of resin material. In order to make the explanation simple, the terminal case body 30 is shown in a transparent manner. Both of the case halves 30a and 30b are rotatably coupled by one or more hinges 19 so that both of the case halves 30a and 30b can be opened and closed around the hinge 19. A lock mechanism 20 is provided at the right hand portion of the outside of the terminal case 30. The locking mechanism 20 comprises a projection 20b projected outward from the bottom case half 30b and a resilient arm 20a projected from the top case half 30a in a generally L character shape so that the the resilient arm 20a can be releasably engaged beneath the lower part of the projection 20b. A printed circuit board 25 is accommodated in the top case half 30a and possible circuit arrangement including such as integrated circuit chip 23 or other necessary components for use in the multiplex transmission terminal is provided on the printed circuit board 25. Such circuit arrangement including the integrated circuit 23 and other components are respectively connected to the conductor patterns 24 formed on the printed circuit board 25 so as to provide a desired terminal circuit. Three pressing connector pins 15, 17 and 18 are downwardly projected from the printed circuit board 25 toward a recess 26 detail of which is explained later and one pressing type connector pin 16 is upwardly projected from the bottom case half 30b toward the recess 26. The connector pins 15 and 16 are so projected that the respective connector ends are opposed in the recess 26 and the connector pin 15 is connected to one of the printed circuit pattern 24. The connector pins 17 and 18 are connected to the other printed circuit patterns 29 and the connector pin 16 is connected to printed circuit pattern 24 through a conductor wire 27. The recess 26 is formed by a combination of elongated recesses 26x extending in a longitudinal direction of each of the case halves 30a and 30b on the respective inner surfaces 31 and 32. The recess 26x has such a shape as to conform to the outside shape of the top half or bottom half of the cable unit 10. By the arrangement mentioned above, when the top case half 30a and bottom case half 30b are closed in a manner shown in Fig. 1, there is formed the recess 26 extending in a longitudinal direction of the cable unit 10. The shape of the recess 26 is complementary to the outer shape of the multiplex cable unit 10, so that the multiplex cable unit 10 is accommodated in the recess 26 clamped by the inner surfaces 26y of the top half 30a or bottom half 30b which defines the recess 26x. The respective connector pins 15 to 18 have their end portions shaped into a fork shape with the ends sharpened so that when the terminal 30 is closed accommodating the cable unit 10, the ends of the respective connector pins 15 to 18 can penetrate the insulation layer 11 of the cable unit 10 and the ends of the connector pins can be pressed and contacted with the conductors 1, 2, 3 and 4 respectively. The connector pin 15 may be supported to the upper half 30a through a resilient member 27 so as to contact to a conductor resiliently. In the arrangement mentioned above, before the terminal 30 is mounted on the cable unit 10, the top case half 30a and bottom case half 30b are opened around the hinge 19 as shown in Fig. 4. The terminal 30 is mounted to the cable unit 10 by fitting the cable unit 10 in the recess 26 in such a manner that the power conductor portion 10f is laid in the generally flat shaped recess 26f and signal conductor portions 10r are laid in the round recesses 26r. Then the terminal 30 is closed as shown in Fig. 1 and Fig. 5 with the top half 30a and bottom half 30b locked in a closed manner by engaging the arm 20a with the projection 20b. When both halves 30a and 30b are closed, the ends of the connector pins 15, 16, 17 and 18 penetrate the insulation layer 11 and the connector pins 15 and 16 contact to the power conductors 1 and 2 respectively and the connector pins 17 and 18 clamp and contact the signal conductors 3 and 4 by their fork shaped ends as shown in Fig. 6. In case the terminal 30 is correctly mounted to the cable unit 10, the respective projections 14 are fitted in the grooves 12 and 13. Fig. 5 shows an example of mounting of the terminal 30 on the cable unit 10 with an electric motor 7 and a lamp 8 coupled to the terminal 30 through connection plug 60 so as to connect the motor 7 and lamp 8 to the connecting pins 21 projected from the side wall of the terminal 30.

Claims: Multiplex transmission terminal which is connected to a cable assembly (10) consisting of at least two pairs of conductors (1,2;3,4) extending parallely, each conductor (1,2;3,4) being covered with an insulation layer (11), comprising: a) a case body (30) composed of a pair of case halves (30a,30b) coupled by coupling means (19) so that both of the halves (30a,30b) are adapted to open and close around said coupling means (19); b) recess means (26) defined in said case body (30) for accomodating a part of said cable assembly (10); c) connecting members (15,16;17,18) provided in said case body (30), corresponding to said conductors (1,2;3,4) and having connecting ends projected into said recess means (26), such that they penetrate said insulation layer (11) and contact the corresponding conductors (1,2;3,4) when being pressed by closing both case halfes (30a,30b), characterized in that d) one of said connecting members (15) is projected from one case half (30a) and the remaining connecting members (16,17,18) are projected into the recess (26) from the other case half (30b), the terminal thereby being connectable to said cable assembly, wherein said two pairs of conductors (1,2,3,4) are arranged with respect to each other such that d1) respective distances between one conductor (1) of said first pair of conductors and anyone conductor of said second pair of conductors (3,4) are equal, and d2) respective distances between the other conductor (2) of said first pair of conductors (2) and anyone conductor of said second pair of conductors are equal, thereby minimising electromagnetic interaction between said first and second pair of conductors (1,2,3,4). A multiplex transmission terminal according to claim 1, wherein said coupling means is constituted of one or more hinges (19) provided on one side of said case body (30). A multiplex transmission terminal according to claim 2, wherein said case body (30) further comprises lock means (20) provided on the side opposite to the hinge (19) for locking the case body (30) in a closed state. A multiplex transmission terminal according to claim 1, wherein said connecting members (15,16;17,18) extend transversly to said two pairs of conductors (1,2;3,4). A multiplex transmission terminal according to claim 1, characterized by a resilient member (27) to resiliently support one of said connector members to one case half (30a). A multiplex transmission terminal according to claim 1, characterized in that a printed circuit board (25) is accomodated in one case half (30a). A multiple transmission terminal according to claim 1, characterized in that the shape of the recess in said terminal is complementary to the outer shape of said cable assembly. A multiple transmission terminal according to claim 1, characterized in that said first pair of conductors in said cable assembly (10) are low impedance power supply conductors. A multiple transmission terminal according to claim 1, characterized in that said second pair of conductors in said cable assembly (10) are signal conductors. A multiple transmission terminal according to claim 1, characterized in that said first pair of conductors (1,2) are a pair of generally flat plates opposed to each other and extending parallely; and A multiple transmission terminal according to claim 1, characterized in that said second pair of conductors (3,4) are a pair of round wires.

Inventors: KOBAYASHI, YOSHINOBU OSAKA WORKS
Applicants: SUMITOMO ELECTRIC INDUSTRIES LIMITED
Application year: 1988
Main classification: H01R9
IPC codes: H01R4, H01R9