Electric connector for coaxial ribbon cable

An electric connector for coaxial ribbon cable comprises a guide block for positioning one end of a coaxial ribbon cable to be connected, a cable clamp coupled to the guide block for clamping the coaxial ribbon cable and a housing having the body of a ground contact disposed in the center thereof, and at least one signal contact disposed therein at either sides of the body of the ground contact. The ground contact is provided with any number of contacting sections. These contacting sections are located in the housing in the same line as the signal contacts are arranged. In connecting a coaxial ribbon cable to the electric connector, the top ends of the ground contact and the signal contacts can be connected to the outer conductors and the inner conductors respectively, of one end of the coaxial ribbon cable as positioned in the guide block.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an electric connector for connecting as coaxial 
ribbon cable. 
2. Description of the Prior Art 
Recently, the propagation speeds of integrated circuits used in computer 
circuit systems have become higher and higher. Therefore, in transmitting 
a signal between circuit boards or assemblies, coaxial cables have been 
more frequently used for the purpose of minimizing incoming noises or 
crosstalks. Heretofore, connection of such a coaxial cable to a circuit 
board was effected by individually soldering the center conductor and the 
ground conductor of the coaxial cable to the corresponding terminals fixed 
to the circuit board. This was a time-consuming and costly operation. 
However, in order to avoid such an operation, an expensive coaxial 
connector must have been used. On the other hand, recently, as a 
countermeasure to high density package due to increase in the number of 
signals appearing in circuit systems, a coaxial ribbon cable has been 
developed for use in interconnecting the circuit systems. One type coaxial 
ribbon cable comprises a common outer jacket and a plurality of coaxial 
cables arranged in parallel to one another within the jacket. Another type 
coaxial ribbon cable comprises a plurality of single coaxial cables 
adhered together parallel to one another. Each of the coaxial cables has a 
center conductor for transmitting high speed pulse signals, an outer 
conductor for shielding the center conductor against external 
interferences and a dielectric for isolating the center conductor from the 
outer conductor. The outer conductor may be in the form of a woven 
metallic wire or a coiled metallic wire or a metallic foil surrounding the 
dielectric. Electric connectors for connecting such a coaxial ribbon cable 
have been proposed and used. However, these connectors have the 
disadvantages that their packaging density is low, they can be used only 
for certain coaxial ribbon cables, they are not suitable for connecting a 
small coaxial ribbon cable, they are not economical because the same 
number of ground terminals as there are signals is required and the high 
speed transmitting characteristics in the connecting part are 
unsatisfactory. Moreover, according to a given frequency and noise margin, 
it is often necessary to selectively change the arranged pattern of ground 
terminals. However, in the conventional electric connectors, it was 
difficult to realize such a change of ground pattern. 
Therefore, it is an object of this invention to eliminate the above 
disadvantages and provide an electric connector for coaxial ribbon cable 
wherein a high density packaging can be realized and the change of ground 
pattern can be easily effected. 
SUMMARY OF THE INVENTION 
An electric connector for coaxial ribbon cable according to this invention 
comprises a guide block for positioning one end of a coaxial ribbon cable 
to be connected, a cable clamp coupled to the guide block for clamping the 
coaxial ribbon cable, and a housing having the body of a ground contact 
disposed in the center thereof. At least one signal contact is disposed 
therein at either sides of the body of the ground contact, said ground 
contact being provided with a predetermined number of contacting sections. 
The contacting sections are located in the same line as said signal 
contacts are arranged, whereby the top ends of said ground contact and 
said signal contacts can be connected to the outer conductors and the 
inner conductors respectively, of one end of said coaxial ribbon cable as 
positioned in said guide block when said coaxial ribbon cable is connected 
to said electric connector. 
Preferred embodiments of this invention will be described in connection 
with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1, there is shown an electric connector for coaxial 
ribbon cable comprising a housing 10 in which signal contacts and a ground 
contact are arranged, a guide block 20 about which one end of a coaxial 
ribbon cable 40 to be terminated is wrapped and positioned and a cable 
clamp 30 coupled to the guide block 20 for fixing the one end of the 
coaxial ribbon cable. The housing 10 may be made of an insulating 
material, such as plastic, and is provided at its forward end with signal 
contact receiving apertures 11A for accommodating signal contacts which 
may make contact with the corresponding signal contacts of a mating 
connector, and ground contact receiving apertures 12A for receiving the 
ground contacts of the mating connector as arrayed in two rows. In this 
embodiment, apertures 11B are not in use and remain empty. These apertures 
will be described in further detail hereinafter. 
FIG. 2 illustrates an example of a signal contact adapted to be disposed in 
the signal contact receiving apertures 11A of the housing. The signal 
contact 50 may be integrally formed of a resilient and conductive sheet 
material and has a terminating section 51 having a wire receiving slot 52 
for terminating one of the center conductors of the coaxial ribbon cable 
at one end thereof, an anchoring section 53 for engaging the inner wall of 
the aperture of the housing 10 to securing the contact 50 in place within 
the aperture at the intermediate portion thereof, and a cantilever contact 
spring section 54 for receiving and making electrical contact with the 
signal contact of a mating connector which will be inserted through the 
aperture 11A at the other end thereof. The wire receiving slot 52 is 
preferably provided in a position shifted by a half of the pitch of a 
coaxial ribbon cable to be connected from the center line of the 
cantilever contact spring section 54. This will make it possible to 
position the wire receiving slots 52 of the signal contacts 50 in a 
staggered arrangement so that the pitch of the wire receiving slots 52 
arranged may be equal to the pitch of the center conductors of the coaxial 
ribbon cable, as best shown in FIG. 7, by arranging the signal contacts 50 
in the apertures of the housing 10 in one row in an orientation opposite 
to that of the signal contacts 50 arranged in the apertures in the other 
row. 
FIG. 3 illustrates an example of ground contact as disposed in the ground 
contact slot 13 of the housing 10. The ground contact 60 may be integrally 
formed of a resilient and conductive sheet material and has a plurality of 
legs for electrically terminating to the outer conductors of the coaxial 
ribbon cable at one end thereof. These legs comprises long legs 61 and 
short legs 62 alternately arranged. The top ends 61A of the long legs 61 
are tapered, and the top ends 62A of the short legs 62 are flat. The roots 
of these legs are notched to provide enlarged openings 63. The width of 
the openings 63 is preferably slightly larger than the outer diameter of 
the inner dielectric of the coaxial ribbon cable, thereby preventing the 
legs from contacting the inner conductors of the cable. Of course, the 
pitch of the openings 63 arranged is equal to that of the coaxial ribbon 
cable. The ground contact 60 is provided at the other end with contacting 
sections 64 for receiving and making electrical contact with the ground 
contacts of a mating connector which will be inserted through the 
apertures 12A of the housing 10. Moreover, the ground contact 60 is 
preferably provided with projections 65 and 66 for engaging the wall of 
the slot of the housing 10 to firmly secure the ground contact 60 within 
the slot of the housing 10. 
The guide block 20 may be formed of an insulating material such as plastic. 
The guide block 20 is provided in the top surface with a recess 21 for 
receiving and positioning one end of a coaxial ribbon cable to be 
terminated (see FIGS. 1 and 7 to 10). The guide block 20 is provided in 
the bottom surface with grooves 22 for receiving and positioning each of 
the inner conductors with the inner dielectrics of the coaxial ribbon 
cable (see FIGS. 7 to 10). Furthermore, the guide block 20 is provided on 
one side with grooves 22A for receiving and positioning the exposed inner 
dielectric with the inner conductors of the coaxial ribbon cable, which 
grooves 22A extend from the grooves 22 in the bottom surface to the recess 
21 in the top surface of the block 20 (see FIGS. 7 to 10). The pitches of 
the grooves 22 and 22A are made equal to that of the coaxial cables within 
the coaxial ribbon cable. In addition, the guide block 20 has a recess 
(not shown) formed in the bottom surface thereof, which recess is for 
receiving the top ends of the press contact connecting parts 51 of the 
signal contacts 50 disposed in the housing 10. Moreover, the guide block 
20 is provided with a slot (not shown) extending from the center of the 
recess to the top surface of the guide block, which slot is for receiving 
the long and short legs 61 and 62 of the ground contact 60. To facilitate 
receiving of the long and short legs 61 and 62 of the ground contact 60, 
the slot is preferably shaped so that the width of the slot is largest on 
the receiving end for the long and short legs 61 and 62 and smaller in a 
position more distant from the receiving end. Moreover, the guide block 20 
is provided at the other side with an arch part 24 forming arched openings 
23 for receiving the inner dielectrics with the inner conductors of the 
coaxial ribbon cable, thereby preventing the inner dielectrics from 
getting out of position (see FIG. 1). 
The cable clamp 30 may be formed of an insulating material such as plastic. 
The cable clamp 30 is provided in its bottom surface with a recess (not 
shown) for receiving the top ends of the long legs 61 of the ground 
contact 60 disposed in the housing 10. 
How to connect a coaxial cable to the electric connector described above 
will be described in detail. 
Firstly, as shown in FIG. 4, one end of a coaxial ribbon cable 40 to be 
terminated is processed so that a predetermined length L.sub.1 of the 
outer jacket 41 and the outer conductors 42 as used for ground lines of 
the coaxial ribbon cable 40 is stripped off, separating the inner 
conductors 44 as used for signal lines with the inner dielectrics 43 and 
then a predetermined further length L.sub.2 of the outer jacket 41 is 
stripped off to expose the outer conductors 42. Secondly, as best shown in 
FIGS. 7 and 9, the one end of the coaxial ribbon cable 40 thus processed 
is wrapped about the guide block 20 so that the exposed outer conductors 
42 are positioned in the recess 21 on the top surface of the guide block 
20 and the separated inner conductors 44 with the inner dielectrics 43 are 
positioned in the grooves 22A in the side and the grooves 22 in the bottom 
surface of the guide block 20. In this case, the forward ends of the inner 
conductors 44 with the inner dielectrics 43 are inserted into the arched 
openings 23 of the arch part 24 of the guide block 20 to prevent them from 
getting out of position, as shown in FIG. 1. 
The apertures for each contact of the housing 10 will be described in 
further detail in connection with FIG. 6, which is a partially cut-away 
perspective view of the housing 10. The housing 10 is provided with a 
plurality of signal contact apertures 11 for accommodating each signal 
contact 50 arranged in two rows. These apertures 11 communicate with the 
respective signal contact receiving apertures 11A as described above in 
connection with FIG. 1. Furthermore, the housing 10 has contacting section 
receiving apertures 12 for accommodating the contacting parts 64 of the 
ground contact 60 aligned with one row of the apertures 11. These 
apertures 12 communicate with the respective ground contact receiving 
apertures 12A as described above in connection with FIG. 1. Moreover, the 
housing 10 is provided with a ground contact slot 13 extending through the 
central part thereof to interconnect the contacting section receiving 
apertures 12. The ground contact slot 13 is for receiving the body of the 
ground contact 60 having the projections 65 and 66 (see FIG. 3). In this 
embodiment, the housing 10 also has apertures 11' formed therein. The 
apertures 11' communicate with the respective apertures 11B as described 
above in connection with FIG. 1. However, the apertures 11' will not be in 
use, remaining empty. 
AS shown in FIG. 7, then the signal contacts 50 as shown in FIG. 2 are 
inserted into the respective signal contact apertures 11 of the housing 10 
and the ground contact 60 as shown in FIG. 3 is inserted into the 
contacting section receiving apertures 12 and the ground contact slot 13 
of the housing 10. The guide block 20 about which the one end of the 
coaxial ribbon cable 40 has been wrapped as described before is coupled to 
the housing 10 wherein the contacts have been disposed as described above 
in the following manner. 
As shown in FIG. 7, by means of a suitable backing up tool 80 abutting the 
top surface of the guide block 20, the guide block 20 is pressed to the 
housing 10. Then, the top ends of the long legs 61 of the ground contact 
60 pass through the recess of the guide block 20 and between the adjacent 
exposed outer conductors 42 of the coaxial ribbon cable 40 to project from 
the outer jacket 41. The top ends 62A of the short legs 62 of the ground 
contact 60 pass through the recess of the guide block 20 to push up the 
peripheries of the exposed outer conductors 42 of the coaxial ribbon cable 
40. This is shown in FIG. 8. Simultaneously, the separated inner 
conductors 44 with the inner dielectrics 43 of the coaxial ribbon cable 
are press fitted into the wire receiving slots 52 of the terminating 
sections 51 of the signal contacts 50 to thereby effect press contact 
connecting of the inner conductors 44 with the signal contacts 50. 
A solder plate as used for reinforcing the electric contact of the ground 
contact 60 with the other conductors 42 of the coaxial ribbon cable 40 
will be described in connection with FIG. 5, which illustrates an example 
of the solder plate. The solder plate 70 comprises a supporting plate 71 
and a solder tape 72. The supporting plate 71 may be made of a metallic 
sheet. The supporting plate 71 and the solder tape 72 may be separated or 
the solder tape 72 may be adhered to the supporting plate 71. The 
supporting plate 71 and solder tape 72 have through-holes 71A and 72A 
respectively, for permitting the top ends 61A of the long legs 61 of the 
ground contact 60 to pass therethrough. The through-holes are preferably 
positioned out of the center line of the plate 70, thereby leaving an area 
of the plate 70 against which a suitable heating plate is permitted to 
abut. Preferably, the solder tape 72 contains a flux. 
As shown in FIG. 9, the solder plate 70 as shown in FIG. 5 is placed on the 
top surface of the guide block 20 coupled to the housing 10 so that the 
top ends 61A of the long legs 61 of the ground contact 60 projecting from 
between the adjacent exposed outer conductors 42 of the coaxial ribbon 
cable 40 wrapped about the guide block 20 pass through the holes 71A and 
72A of the solder plate 70, with the solder tape 72 contacting the outer 
conductors 42. Under this condition, a suitable heating plate (not shown) 
is placed over the supporting plate 71 of the solder plate 70 and on the 
top ends 61A of the long legs 61 of the ground contact 60 projecting from 
the solder plate 70 to heat them. Then, the solder tape 72 is melted and 
flows over the outer conductors 42 of the coaxial ribbon cable, the 
supporting plate 71 of the solder plate and the top ends 61A of the long 
legs 61 and the top ends 62A of the short legs 62 of the ground contact 
60, thereby resulting in close soldering among them and thus a reinforced 
electric contact of the outer conductors 42 of the coaxial ribbon cable 
with the ground contact 60. This is shown in FIG. 10, wherein reference 
numeral 72' indicates a fused solder. The cable clamp 30 is then coupled 
to the assembly of the guide block 20, the housing 10 and the coaxial 
ribbon cable 40 shown in FIG. 10 to complete the connection of the coaxial 
ribbon cable 40 with the electric connector as shown in FIG. 1. The 
coupling of the guide block 20 to the housing 10 is locked by the 
engagement of latching torques 14 provided at both sides of the housing 10 
with the upper surfaces of projections 25 on both sides of the guide block 
20, as shown in FIG. 1, and the coupling of the cable clamp 30 to the 
guide block 20 is locked by latching legs 31 provided at both sides of the 
cable clamp 30 which legs 31 are inserted into through-apertures 26 (see 
FIG. 9) provided at both sides of the guide block 20 to engage with the 
lower ends of the projections 25 of the guide block 20, as shown in FIG. 
1. 
To more clearly show the arrangement of the signal contact receiving 
apertures and the ground contact receiving apertures of the electric 
connector as described above, the end of the electric connector as viewed 
from the direction of arrow A in FIG. 1 is shown in FIG. 11, wherein 
reference character S indicates signal contact receiving apertures, 
reference character G indicates ground contact receiving apertures and 
reference character E indicates apertures not in use, being empty. 
FIGS. 12A and 12B illustrate different ground contacts which can be 
substituted for the ground contact 60 as shown in FIG. 3 to provide 
different ground patterns. The ground contact 60A as shown in FIG. 12A has 
three contacting sections 64A. By utilizing the ground contact 60A and 
modifying the housing 10 accordingly, an electric connector having an 
arrangement of signal contact receiving apertures and ground contact 
receiving apertures as shown in FIG. 13A can be obtained. Similarly, a 
ground contact 60B as shown in FIG. 12B can provide a different ground 
pattern. The ground contact 60B has four contacting parts 64B. By 
utilizing the ground contact 60B and modifying the housing 10 accordingly, 
an electric connector having an arrangement of signal contact receiving 
apertures and ground contact receiving apertures as shown in FIG. 13B can 
be obtained. 
Although in the embodiments as described before the connection of the outer 
and inner conductors of the coaxial ribbon cable with the ground contact 
and signal contacts of the electric connector is made by soldering and 
press contact connecting process, this invention is not limited to such 
process, but may be applied to electric connectors having other connecting 
mechanism. 
The embodiments of electric connector according to this invention described 
above provide the following advantages: 
(1) Since one end of a coaxial ribbon cable to be connected is wrapped 
about the guide block so that the electric connection of the signal 
contacts with the inner conductors of the coaxial cable and the electric 
connection of the ground contact with the outer conductor of the coaxial 
cable can be made in two different levels and the signal contacts are 
arranged in two rows, it is possible to reduce the entire dimensions of 
the electric connector and to easily perform simultaneous connection of a 
number of inner and outer conductors. Moreover, since the contacting 
sections of the ground contact are arranged in the same row as the signal 
contacts, only two rows of the contact receiving apertures are required. 
This results in the minimum thickness of the housing, which leads to high 
density packaging. 
(2) Since the body of the ground contact is interposed between the two rows 
of the signal contacts, it is easy to adjust the impedance. Moreover, by 
suitably selecting the position and the number of the ground contacting 
sections (as indicated by reference numerals 64, 64A and 64B in FIG. 3, 
FIGS. 12A and 12B) with respect to the number of the inner conductors of 
the coaxial ribbon cable, i.e., the number of signals, a suitable ground 
pattern can be easily determined so that crosstalk due to feedback current 
in the electric connector may be prevented. 
(3) Since the individually separated outer conductors, i.e., ground lines 
of the coaxial ribbon cable are commonly connected to the common ground 
contact of the electric connector, it is possible to reduce the number of 
grounds to be connected to an external system with respect to the number 
of signals. This is economical. 
(4) Since the grooves and arched openings of the guide block prevent the 
inner conductors of the coaxial cable from getting out of position upon 
connecting, current press contact connecting can be carried out. 
(5) Since the electric connector can be applied to various coaxial ribbon 
cables such as a coaxial ribbon cable having a woven shield and a coaxial 
ribbon cable having a coiled shield, it is universal in this meaning.