Totally shielded electrical jack assembly for modular plugs

A totally shielded electrical jack assembly adapted for connecting a modular plug to a cable, including a jack frame adapted for receiving the modular plug and having a base and a front box in front of the base, a top cover coupled to and covered on the base of the jack frame, an electrical connector unit mounted inside the jack frame and adapted for electrically connecting the modular plug to the cable, and shield means mounted inside the jack frame, the shield means including a shield frame mounted inside the jack frame, and a cover shell mounted in the top cover, the shield frame and the cover shell being made from metal and coupled together and covered around the electrical connector unit to protect it against magnetic noises.

BACKGROUND OF THE INVENTION 
The present invention relates to electrical jack assemblies for modular 
plugs, and more particularly to a totally shielded electrical jack 
assembly which meets the specification of FCC (Federal Communications 
Commission) 68 type. 
A variety of electrical connectors, including modular jacks and modular 
plugs have been developed, and intensively used for connection between 
cables and computers networks or telecommunication apparatus. These 
electrical connectors must meet relative specifications defined by Federal 
Communication Commission. Exemplars of these connectors are seen in U.S. 
Pat. No. 5,186,647 entitled "HIGH FREQUENCY ELECTRICAL CONNECTOR"; U.S. 
Pat. No. 5,310,363 entitled "IMPEDANCE MATCHED REDUCED CROSS TALK 
ELECTRICAL CONNECTOR SYSTEM"; U.S. Pat. No. 5,299,956 entitled "LOW CROSS 
TALK ELECTRICAL CONNECTOR SYSTEM"; Chinese Pat. Publication No. 224,547 
entitled "TELECOMMUNICATION CONNECTOR TERMINAL". These electrical 
connectors and connector terminal meet the defined specifications, however 
they have no means to protect against the interference of external 
magnetic noises. Electrical connectors with shield means are seen in U.S. 
Pat. No. 5,288,248 entitled "TOTALLY SHIELDED DIN CONNECTOR", U.S. Pat. 
No. 5,338,215 entitled "JACK ASSEMBLY INCLUDING A CONTACT SWITCHING 
SYSTEM"; U.S. Pat. No. 5,083,945 entitled "SHIELDED ELECTRICAL CONNECTOR 
ASSEMBLY"; U.S. Pat. No. 5,480,326 entitled "ELECTRICAL JACK ASSEMBLY FOR 
MODULAR PLUGS". These electrical connectors commonly have a metal shield 
covered on the outside to protect against the interference of external 
magnetic noises. These electrical connectors are functional, however they 
cannot protect against the interference of static noises when touched by 
an object. Furthermore, because the metal shield is exposed to the 
outside, it tends to cause an electric shock when receives a big amount of 
static electricity and the ambient air is dry, or when in a thunderous 
day. 
SUMMARY OF THE INVENTION 
It is one object of the present invention to provide an electrical jack 
assembly which has a shield means mounted on the inside and kept from 
sight to protect the contacts between the conductors of the cable and the 
terminals of the modular plug against the interference of external 
magnetic noises. It is another object of the present invention to provide 
an electrical jack assembly which has a shield means mounted within the 
insulative jack frame thereof to protect the contacts between the 
conductors of the cable and the terminals of the modular plug against the 
interference of external magnetic noises. It is still another object of 
the present invention to provide an electrical jack assembly which has a 
metal shield means for protection against external magnetic noises, and an 
insulative jack frame covered around the metal shield means to prevent the 
metal shield means from causing an electric shock.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1, 2-1, and 2--2, an electrical jack assembly in 
accordance with the present invention comprises jack frame 2 adapted for 
receiving a modular plug, a top cover 1 covered on the rear side of the 
jack frame 2 at the top, an electrical connector unit 5 mounted inside the 
jack frame 2 and adapted for connecting the modular plug to the electrical 
wires 9a (see also FIG. 11-1), and shield means mounted within the jack 
frame 2 and kept from sight. 
The aforesaid electrical connector unit 5 comprises a terminal mounting 
base frame 51, a plurality of for example two holding-down blocks 6, 6', 
and a coupling 7 connected to the terminal mounting base frame 51 at the 
front side. 
The aforesaid shield means comprises a shield frame 4 and a cover shell 3. 
The cover shell 3 and the shield frame 4 are respectively made of metal, 
adapted for connecting to each other and covering over the electrical 
connector unit 5. The shield means protect the electrical connections 
between the electrical connector unit 5, the electrical wires 9a and the 
modular plug against the interference of external magnetic noises. 
The base frame 51 of the electrical connector unit 5 is made of 
electrically insulative material. As shown in Figures from 9-1 to 9-4, the 
terminal mounting base frame 51 comprises an upright wall 52 in the middle 
which divides the terminal mounting base frame 51 into a front part and a 
rear part. The aforesaid coupling 7 is installed in the front part of the 
terminal mounting base frame 51 in front of the upright wall 52. A 
conductor mount 53 is formed at the rear part of the terminal mounting 
base frame 51 behind the upright wall 52, and adapted for holding the 
electrical wires 9a. The conductor mount 53 comprises a plurality of 
upright blocks 531 arranged in a line and separated from one another by 
gaps 532, and a plurality of through holes 533 respectively disposed in 
the gaps 532. 
Referring to FIGS. 11-1 and 11-2, a terminal 50 is mounted in the terminal 
mounting base frame 51, having a front contact end 501 inserted into the 
inside of the coupling 7 for contact of the corresponding terminal of the 
modular plug, and a forked, sharp tail end 502 inserted through one 
through hole 533 and retained in one gap 532. When each electrical wires 
9a is forced into the corresponding gap 532, the forked, sharp tail end 
502 of the terminal 50 is forced to cut through the insulator of the 
corresponding electrical wire 9a and to make electrical contact with the 
conductor of the corresponding electrical wire 9a. Each of the aforesaid 
upright blocks 531 has a neck 534 near the bottom adapted for coupling the 
holding-down block 6. 
Referring to Figures from 10-1 to 10-3, the holding-down block 6 is made of 
electrically insulative material, comprising a plurality of holes 60 
adapted for receiving the upright blocks 531, a plurality of projecting 
portions 61 respectively projecting in the holes 60 and adapted for 
engaging the necks 534 of the upright blocks 531 for permitting the 
holding-down block 6 to be secured to the conductor mount 53, and a 
plurality of pressure boards 62 respectively disposed between each two 
adjacent holes 60, 60' and adapted for press-fitting into the gaps 532. 
When the holding-down block 6 is fastened to the conductor mount 53, each 
pressure boards 62 forces the corresponding electrical wire 9a against the 
forked, sharp tail end 502 of the corresponding terminal 50 (see FIG. 
11-1). The holding-down block 6 has an expanded top 63 convenient for 
manipulation with the hand. 
When the electrical wires 9a are mounted in the conductor mount 53, the 
tail ends 9d of the electrical wires 9a are prohibited from contacting the 
front contact ends 501 of the terminals 50 by the upright wall 52 (see 
FIG. 11-1). The coupling 7 is a hollow rectangular frame having a forward 
opening 71 at each lateral wall. 
The cover shell 3 and shield frame 4 of the aforesaid shield means are 
respectively mounted inside the top cover 1 and the jack frame 2. When the 
top cover 1 is covered on the jack frame 2, the cover shell 3 is 
simultaneously coupled to the shield frame 4 to shield the aforesaid 
electrical connector unit 5. The shield frame 4 is made from a metal 
plate, comprising a bottom frame 40 adapted for carrying the electrical 
connector unit 5, and a shielding body 41 adapted for shielding the 
coupling 7. The shielding body 41 comprises two upright side walls 43, 43' 
bilaterally raised from the bottom frame 40, a top wall 42 connected 
between the upright side walls 43, 43' in parallel to the bottom frame 40, 
a downward front flange 420 extended from the front side of the top wall 
42 at right angles, two inward spring strips 430 respectively extended 
from the upright side walls 43, 43', a downward rear flange 44 downwardly 
extended from the rear side of the top wall 42 at right angles, and two 
upward fingers 45, 45' respectively raised from the rear sides of the 
upright side walls 43. When the coupling 7 is mounted in the shielding 
body 41, the inward spring strips 430 are respectively disposed in the 
forward openings 71 of the coupling 7 in contact with the metal shell of 
the modular plug. The bottom frame 40 comprises an upright rear wall 46 
raised from the rear side, two upright side walls 47, 47' respectively 
raised from two lateral sides, and two upright front walls 48, 48' 
respectively raised from the front side and connected to the rear sides of 
the upright side walls 43 of the shielding body 41. The upright side walls 
47, 47' of the bottom frame 40 have a respective mounting hole 470, 470' 
facing each other, and a respective upward coupling flange 471, 471' 
raised from the top. 
Referring to Figures from 4-1 to 4-3, the cover shell 3 is made from a 
metal plate and adapted for covering over the rear part of the shield 
frame 4, comprising a top wall 32, two downward side walls 31 respectively 
downwardly extended from two opposite lateral sides of the top wall 32 at 
right angles, and a downward rear wall 30 downwardly extended from the 
rear side of the top wall 32 at right angles. The rear wall 30 has a 
downward opening 300 through which the electrical wires 9a pass. Two 
parallel tracks 301, 301' are raised from the rear wall 30 of the cover 
shell 3 to hold a ground element 33. The ground element 33 comprises two 
side wings 330, 330' at two opposite sides forced in between the parallel 
tracks 301, 301', and at least one split 331 adapted for holding one 
grounding wire 9b (see also FIG. 11-1) for permitting the shield means to 
be electrically connected to ground terminal for protection against 
external magnetic noises. The downward side walls 31 of the cover shell 3 
have a respective convex portion 310 made by stamping and adapted for 
coupling to the coupling flanges 471, 471' of the shielding body 41. Each 
convex portion 310 has a sloping bottom edge 311 sloping downwardly 
outwards adapted for guiding the corresponding coupling flange 471 or 471' 
into the inside of the convex portion 310 (see also FIG. 8). The top wall 
32 of the cover shell 3 has an upward contact flange 36 raised from the 
front side, and two contact flanges 37 bilaterally disposed at the front 
side. When the cover shell 3 is coupled to the shield frame 4, the upward 
contact flange 36 is forced into contact with the downward rear flange 44 
of the shield frame 4 (see also FIG. 8). 
Referring to Figures from 3-1 to 3--3, the top cover 1 is a hollow 
rectangular frame made from electrically insulative material and adapted 
for covering over the cover shell 3, comprising a top wall 11, two 
downward side walls 12, a downward rear wall 13, four downward hooks 10 in 
the four corners adapted for hooking on respective notches 20, 21 of the 
jack frame 2, and two inside hooks 14 downward raised from the top wall 11 
near the front side and adapted for hooking on respective front notches 
320, 320' at the front side of the top wall 32 of the cover shell 3. The 
downward rear wall 13 of the top cover 1 has a center opening 130 extended 
upward to the topmost edge through which the ground element 33 can be 
inserted in between the parallel tracks 301, 301'. A hook 15 is raised 
from the inside surface of the downward rear wall 13, and adapted for 
hooking in a notch 35 in the middle of the top side of the downward 
opening 300 of the cover shell 3, for permitting the cover shell 3 to be 
firmly retained inside the top cover 1 (see also FIG. 5). 
The aforesaid electrical connector unit 5 further comprises two triangular 
hooks 54 respectively raised from two opposite lateral sides. When the 
electrical connector unit 5 is mounted on the bottom frame 40 of the 
shield frame 4, the triangular hooks 54 are respectively forced into 
engagement with the mounting holes 470, 470' to secure the electrical 
connector unit 5 and the shield frame 4 together. When the electrical 
connector unit 5 and the shield frame 4 are connected together, they are 
horizontally inserted into the jack frame 2 from the rear side, permitting 
the triangular hooks 54 of the electrical connector unit 5 to be forced 
into corresponding mounting grooves 22 inside the jack frame 2 (see FIG. 
6), and at the same time the coupling 7 is installed in the shielding body 
41 of the shield frame 4 and stopped in place by the downward front flange 
420. 
The aforesaid jack frame 2 has a profile fitting the shield frame 4, 
comprising a base 23 adapted for carrying the electrical connector unit 5, 
a front box 25 disposed at the front side of the base 23 and adapted for 
receiving the shielding body 41 of the shield frame 4, and two upright 
side walls 26, 26' respectively raised from two opposite lateral sides of 
the base 23 at right angles. The front box 25 has a stop flange 250 
fitting over the downward front flange 420 of the shield frame 4 (see also 
FIG. 6) for permitting the shielding body 41 of the shield frame 4 to be 
stopped inside the front box 25. A transverse retaining block 251 is 
raised from the top side of the front box 25. The transverse retaining 
block 251 has a slope gradually sloping backwardly upwards for mounting a 
matched face panel for example a patch panel. The upright side walls 26, 
26' have a respective mounting groove 22 horizontally disposed at an inner 
side, and a respective retaining block 220 vertically disposed in the 
respective mounting groove 22. The retaining block 220 divides the 
respective mounting groove 22 into a front part and a rear part, having a 
bevel edge 221 sloping downwards toward the rear part of the respective 
mounting groove 22. When the triangular hooks 54 of the electrical 
connector unit 5 are respectively inserted into the front parts of the 
mounting grooves 22, they can be forced forwards to pass over the bevel 
edges 221 of the retaining blocks 220 into the front parts of the mounting 
grooves 22, and then hooked up with the retaining blocks 220. 
The assembly process of the present invention is outlined hereinafter. 
i) the terminal mounting base frame 51, holding-down blocks 6 and coupling 
7 of the electrical connector unit 5 are mounted on the base frame 40 of 
the shield frame 4 from the rear side, and then the shield frame 4 with 
the electrical connector 5 are inserted into the base 23 of the jack frame 
2, permitting the triangular hooks 54 of the electrical connector unit 5 
to be respectively forced into engagement with the retaining blocks 220 in 
the mounting grooves 22 of the jack frame 2. 
ii) the cover shell 2 is inserted into the top cover 1 from the bottom, and 
then the terminal element 33 is mounted in between the tracks 301, 301' of 
the cover shell 3. 
iii) the electrical wires 9a of the cable 9 are respectively mounted in the 
gaps 532 of the conductor mount 53, then the holding-down blocks 6 are 
respectively pressed down to force the electrical wires 9a against the 
forked, sharp tail ends 502 of the terminals 50, thereby causing the 
forked, sharp tail ends 502 of the terminals 50 to cut into the insulator 
of the electrical wires 9a and to make contact with the conductors of the 
electrical wires 9a respectively. 
iv) the top cover 1 with the cover shell 3 and the ground element 33 are 
inserted into the rear part of the jack frame 2 from the top, permitting 
the cover shell 3 to be forced into engagement with the shield frame 4 
(see FIG. 8) and the electrical connector unit 5 to be retained on the 
inside. When assembled, the contact flanges 37 of the cover shell 3 are 
respectively disposed in contact with the upward fingers 45, 45' of the 
shield frame 4 (see FIG. 8). 
As indicated above, when the electrical jack assembly is assembled, the 
cover shell 3 and the shield frame 4 are retained inside the top cover 1 
and the jack frame 2 and kept from sight, to effectively protect the 
internal circuit against the interference of external magnetic noises. 
While only one embodiment of the present invention has been shown and 
described, it will be understood that various modifications and changes 
could be made thereunto without departing from the spirit and scope of the 
invention disclosed.