Note: Descriptions are shown in the official language in which they were submitted.
Terminal arrangement for use in a multiplex transmission
system
The present invention relates to a multiplex terminal
arrangement for a multidrop connection used in a multiplex
transmission terminal for an industrial or vehicle system.
To enable the prior art to be described with the aid
5 of diagram the figures of the drawings will first be
listed.
Fig. l is a circuit diagram showing an example of
multiplex kransmission terminal;
; Fig. 2 is a perspective view of an example of a
lO multiplex transmission terminal according to an embodiment
of the present invenkion;
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
15 terminal shown in Fig. 2 with the casing halves opened;
Fig. 5 is a perspective view showing an example of the
multiplex transmission terminal attached to a mul~iplex
cable, and
Fig. 6 is a perspective view of the multiplex
20 transmission terminal attached to the multiplex cable.
Fig. l shows an example of a multiplex transmission
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system using a multidrop connection system. In Fig. 1,
101 and 102 denote power transmission lines for supplying
power to terminals 105 and 106, and 103 and 104 denote
data transmission lines for transmitting data information
5 to the terminals 105 and 106. In the example shown, the
respective terminals 105 and 106 are provided with
actuators 107 and 108, such as an electric motor and a
display lamp, which ar~ activated by the data, in addition
to various switches 109 and 110 for inputting the data.
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 separate
connectors.
However, in the prior art, it has been necessary to
15 connect each cable with the terminal in such a manner
that, after each cable end has been processed, a connector
is attached to the cable end, whereby the cable is
connected to the terminal. Thus the work for connecting
the cable to the terminal is complicated. Moreover, it is
necessary to provide a connector Eor receiving the end
connector of the cable.
An essential object of the present invention is to
provide a multiplex transmission terminal that is easily
mounted on a cable assembly and in which each connecting
25 end of the multiplex transmission terminal can be easily
connected to the cable assembly without any cable
processing.
Another object of the present invention is to provide
a multiplex transmission terminal that can be mounted
anywhere on the cable assembly, as desired.
To this end, the invention consists of a multiplex
transmission terminal for connection to a cable assembly
having power conductors and signal conductors, said
terminal comprising a casing body composed of a pair of
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casing halves connected by coupling means so that the
halves can open and close; recess means defined inside
said casing body for accommodating a part of said cable
assembly; and at least one connecting member provided on
5 one of the casing halves, a connecting end of said
connecting member projected in said recess whereby said
connecting end can contact one of the conductors of said
cable assembly.
Referring to Fig. 3, there is shown a multiplex cable
lO unit 10 used for a multiplex transmission terminal
according to the present invention. The cable unit
comprises a pair of power supply conductors l and 2 of
elongated strip shape extending parallel to each other.
The two conductors l and 2 are as close to each other as
15 possible, while assuring the necessary withstand voltage.
To locate the conductors 1 and 2 close to each other
increases the capacitance between them, whereby to provide
a low impedance power supply line. The cable unit further
comprises a pair of signal conductors 3 and 4 disposed
20 close to each other and extending in parallel along one
side of the power supply conductors l and 2. The
; respective distances between the signal conductor 3 and
the power supply conductors l and 2 are equal to prevent
electrostatic induction from the conductors l and 2. The
respective distances between the conductor 4 and the
conductors l and 2 are also equal.
The conductors l to 4 are covered with an insulation
material ll (referred to as insulation layer hereinafter),
as shown in Fig. 3. Although the conductors 1 to 4 are
covered with this insulation layer ll throughout their
whole length, a terminal can be connected to the
respective conductors 1 to 4 at any desired location on
the multiplex cable unit, as mentioned below.
Referring to Fig. 2, a terminal casing 30 is composed
of a top half 30a and bottom half 30b made of resin
material. The casing 30 is shown transparent to
facilitate the explanation. The casing halves 30a and 30b
are rotatably coupled by one or more hinges 19. A lock
5 mechanism 20 is provided at the right hand portion of the
outside of the casing 30, this locking mechanism 20
comprising a projection 20b extending outwards from the
bottom half 30b and a resilient arm 20a projected from the
top half 3ûa in a generally L shape, so that the resilient
10 arm 20a can be releasably engaged beneath the lower part
of the projection 20b.
A printed circuit board 25 is accommodated in the top
half 30a, a circuit arrangement including such elements as
an integrated circuit chip 23 or other components for use
15 in the multiplex transmission terminal, being provided on
the printed circuit board 25. The components of such
circuit arrangement are respectively connected to
conductor patterns 24 formed on the printed circuit board
25, whereby to provide a desired terminal circuit.
Three pressing connector pins 15, 17 and 18 project
downwardly from the printed circuit board 25 toward a
recess 26, details of which are explained later, and one
pressing type connector pin 16 projects upwardly from the
bottom half 30b toward the recess 26. The connector pins
25 15 and 16 are so arranged 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 other
printed circuit patterns 29, and the connector pin 16 is
30 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 casing halves 30a and 30b on respective inner
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suraces 31 and 32. The recess 26x has a shape that
conforms to the outside shape of the cable unit 10. With
this arrangement, when the half 30a and the half 30b are
closed, in a manner shown in Fig. 2, a recess 26 is formed
5 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 and
10 bottom half 30b which define the recess 26x.
The respective connector pins 15 to 18 have their end
portions fork shaped with the ends sharpened so that when
the terminal 30 is closed about the cable unit 10, the
ends of the respective connector pins 15 to 18 penetrate
15 the insulation layer 11 of the cable unit 10 and the ends
of the connector pins are pressed into contact with the
conductors 1, 2, 3 and 4, respectively. The connector pin
15 can he supported on the upper half 30a by a resilient
member 27a so as to contact to the conductor 1 resiliently.
Before the terminal 30 is mounted on the cable unit
10, the casing halves are opened at the hinge 19, as shown
in Fig. 4. The terminal 30 is mounted on the cable unit
10 by fitting the cable unit 10 in the recess 26 in such a
manner that the power conductor portion lOf is laid in the
25 generally flat shaped recess 26f and the signal conductor
portions lOr are laid in the round recesses 26r. The
terminal 30 is then closed as shown in Figs. 2 and 5, with
the casing halves locked in the closed position by
engaging the arm 20a with the proiertion 20b. The ends of
30 the connector pins 15, 16, 17 and 18 now penetrate the
insulation layer 11 and the connector pins 15 and 16
contact the power conductors 1 and 2 respectively, while
the connector pins 17 and 18 clamp and contact the signal
conductors 3 and 4 with their fork shaped ends, a shown in
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Fig. 6. Projections 14 fit into grooves 12 and 13.
Fig. 5 shows an example of mounting a terminal 30 on
the cable unit 10 with an electric motor 7 and a lamp 8
coupled to the terminal 30 through a connection plug 60,
5 whereby to connect the motor 7 and lamp 8 to the
connecting pins 21 projected from the side wall of the
terminal 30.
~ s described above, an advantage o the present
invention resides in that the terminal 30 can be mounted
10 on the cable unit 10 with only a clamping operation. It
is easy to have the connector pins contact the conductors
o the cable unit, without the need to work on the cable,
such as cable cutting and end processing. Moreover, since
no connector member is necessary, the cost of connecting
the terminal to the cable is reduced.
Another advantage of the present invention is that the
terminal can readily be mounted anywhere desired along the
cable.
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