Note: Descriptions are shown in the official language in which they were submitted.
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~lODULAR JACK FOR PLUG-IN COMMUNICATION
TERMINALS AND METHOD OF MOULDING SAME
This invention rela-tes to modular jacks for
electrically connecting plug-in communications terminals to
communications transmission lines and a method oF moulding such jacks.
Typical known modular jacks for connecting plug-in
communications terminals, such as telephones, to communications
transmission lines, such as telephone lines, comprise a base of a
housing for mounting to a wall or similar support structure, screw
terminals carried by the base for terminating the transmission line, a
plug receptacle carried by the base and electrically connected to the
screw terminals for receiving a plug of the plug-in terminal, and a
cover of the housing which fits over the base to enclose the
terminals. Other known jacks for connecting plug-in telephones to
telephone lines have screw terminals carried by the base and a plug
receptacle carried by the cover, conductive spring contacts being
provided to electrically connect the terminals to the plug receptacle
when the cover is fitted to the base (see for example, U.S. Patent No.
4,050,768 issued to B.W. Gumb on the 27th September 1977).
According to the present invention there is provided a
modular jack for electrically connecting a plug-in communications
terminal to a communications transmission line, the jack comprising: a
housing consisting of a one piece shell defining a cavity, the shell
having an opening therethrough into the cavity and an inlet for
permitting entry of the transmission line into the cavity; terminal
means carried by the shell inside the cavity for terminating the
transmission line, the terminal means being accessible through the
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opening; and plug receiving means carried by the shell and accessible
from outside the shell for receiving plug means of the plug-in
terminal, and for electrical connection to the terminal means, the
jack being mountable to a support structure to close the opening.
Thus, modular jacks constructed according to the
present invention rely on a housing consistiny of a one piece shell to
support and protect a connection between a plug-in terminal and a
transmission line, whereas previously known modular jacks rely on a
housing consisting of a separable base and cover to perform these
functions. In view of this, modular jacks according to the present
invention have fewer housing parts, and therefore may be more
economical to manufacture and easier to install and remove than
previously known jacks.
Modular jacks according to the invention may be mounted
to a support structure by any convenient means. For example, a boss
carried by the shell may be provided, the boss having a bore
therethrough for passage of a screw to secure the shell to a support
structure. Alternatively, a fastening device such as a spring clip
may be mounted on the support structure for location across the shell
to secure the shell to the support structure.
According to another aspect of the invention there is
provided a method of moulding a shell for a modular jack, comprising:
mounting a plurality of insulation displacement terminal strips in
recesses provided in a moulding surface of at least one mould body,
with the strips having portions projecting from the moulding surface;
relatively moving the at least one mould body and at least one other
mould body into positions in which moulding surfaces of the mould
bodies define a mould cavity in the shape of the shell, and with the
strip portions projecting into the mould cavi-ty; injecting flowable
plastics material into the mould cavity to fill and surround the
terminal portion, the plastics material after solidifying forming the
shell with the terminal portions embedded in the shell.
An embodiment of the invention will now be described in
the following with reference to the accompanying drawings, in which:
Figure 1 is an exploded perspective view of a typical
prior art modular jack;
Figure 2 is a plan view of a modular jack constructed
according to an embodiment of the invention;
Figure 3 is a cross-sectional view of the jack of
Figure 2 taken along section line III-III in Figure 2;
Figure 4 is an end elevation view of the jack of Figure
2 taken in the direction of arrow IV in Figure 2;
Figure 5 is a view similar to Figure 2 showing the jack
mounted to a wall;
Figure 6 is a cross-sectional view of mould bodies for
moulding the modular jack of Figure 2, at a section corresponding to a
sec-tion of the jack taken along line VI-VI in Figure 2; and
Figure 7 is a cross-sectional view of mould bodies for
moulding the modular jack of Figure 2, at a section corresponding to a
section of the jack taken along line III-III in Figure 2.
A typical known modular jack 10 for connecting a
plug-in terminal, such as a telephone, to a transmission line, such as
a telephone line, is shown in Figure 1. The device 10 comprises a
housing formed of two parts. One of these parts is a base 12 with
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screw terminals 14 and a plug receptacle 16 carried by the base 12.
The other housing part is a cover 18 which fits over the base 12 to
enclose the terminals 14. Insulated wires 20 electrically connect the
terminals 14 to corresponding electrical contacts 22 of the plug
receptacle 16. The base 12 includes bosses 24 having bores 26
therethrough. ~hen the cover 18 is fitted to the base 12, an opening
28 through the cover 18 aligns with a recess 30 in the base 12, and an
aperture 32 through the cover permits insertion of the plug into the
plug receptacle.
In use, the base 12 is mounted to a support structure,
such as a wall, by means of screws through the bores 26. A telephone
line is passed through the recess 30 and individual conductors of the
telephone line are terminated on respective screw terminals 14, so as
to be electrically connected to corresponding contacts 22 of the plug
receptacle 16 via insulated wires 20. The cover 18 is fitted to the
base 12, the telephone line passing through the opening 28 in the
cover 18. A plug connected to a plug-in telephone may now be inserted
through the aperture 32 into the plug receptacle 16 to connect the
plug-in telephone to the telephone line.
A modular jack constructed according to an e~bodiment
of the invention is shown in Figures 2, 3 and 4. The jack 100
comprises a housing consisting of a one piece shell 102. The shell
102 has a planar base wall 104 and a continuous edge flange formed by
side walls 106 projecting normal to the base wall 104. The base wall
104 and side walls 106 define a cavity 108 which has an opening 109
remote from the base wall 104, the opening 109 being defined between
the side walls 106. An inlet to permit entry of a telephone line is
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provided by a slot 110 in one of the walls 106.
Terminal means in the form of terminal strips 112, each
comprising three electrically connected insulation displacement
terminals 113 are carried by the shell 102 on the base wall 104 inside
the cavity 108. Plug receiving means in the form of a Teledapt~
receptacle 114 is carried by shell 102 inside cavity 108, the shell
102 having an aperture 115 for insertion of a plug into the receptacle
114. (Teledapt~ is a Registered Trade Mark of Northern Telecom
Limited.)
The Teledapt~ receptacle 114 has walls 116, 117, 118,
119 defining a channel 120. One of the walls 116 includes formations
in the form of steps 122. A bridge member 124 extends across one end
of the channel 120, and has formations defining grooves 126. The
Teledapt~ receptacle 114 further comprises resilient electrical
contacts 128 extending from a wall 118 of the channel 120 to the
bridge member 124, each resilient electrical contact 128 having a free
end 129 slidably received in a respective one of the grooves 126.
Each of the resilient electrical contacts 128 is electrically
connected ~o a corresponding insulated wire 130 at a crimp connection
housed in the wall 118 from which the resilient electrical contacts
128 extend. The insulated wires 130 may be used to electrically
connect each of the contacts 128 to a corresponding one of the
terminal strips 112.
Mounting means for the connection device is provided in
the form of a boss 132 carried by the shell 102. The boss 132 has a
bore 134 therethrough and a frustoconical surface 136 adjacent the
bore 134 for engaging the head of d screw.
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In use, a telephone line 200 (see Figure 5) is passed
through the inlet 110, and individual conductors 202 of the telephone
line 200 are terminated on selected terminals 113 of the terminal
strips 112. The telephone line 200 may be knotted as shown in Figure
5 to provide strain relief. The device 100 is placed against a
support structure, such as a wall 300, such that the cavity 108 faces
toward the wall 300, the wall 300 closing the opening 109. A screw
400 is passed through the bore 134 in boss 132 and driven into the
wall 300, a head 402 of the screw engaging the surface 136 of the boss
132 to mount the device 100 to the wall 300.
A Teledapt~ plug 500 connected to a plug-in telephone
may then be inserted into the Teledapt~ receptacle 114 to connect the
plug-in telephone to the telephone line 200. The channel 120 of the
Teledapt~ receptacle 114 has a predetermined profile for reception of
the Teledapt~ plug 500, and the steps 122 engage complementary step
formations 502 on a resilient portion 504 of the Teledapt~ plug 500 to
retain the plug 500 in the channel 120. Electrical contacts 506 of
the Teledapt~ plug 500 engage corresponding resilient contacts 128 of
the Teledapt~ receptacle 114. As the plug 500 is urged into the
receptacle 114, the resilient contacts 128 resiliently deform, their
free ends 129 sliding in the grooves 126.
The shell may be mounted to a support structure by
convenient means other than the boss 132 included in the embodiment
described above. For example, a fastening device such as a spring
clip may be mounted on the support structure for location across the
shell to secure the shell to the support structure.
The boss 132 and the walls 116, 117, 119 and bridge
member 124 of the receptacle 114 are integrally moulded as part of the
shell 102. Wall 118 of the receptacle is separately moulded, provided
with insulated conductors 130 and resilient electrical contacts 128
and fixed to the other parts of the receptacle 114. Terminal strips
112 have portions which are embedded in formations 138 of the shell to
hold the strips firmly in place. The formations 138 are projections
formed integrally with the shell 102 and project into the cavity 108
from the base wall 104. Alternatively, the terminal strips are
pressed into preformed grooves in the formations 138.
The shell 102 and its integrally moulded parts are
conveniently made by a process now to be described with reference to
Figures 6 and 7. Figures 6 and 7 show cross-sections through mould
bodies for forming the shell 102. A first mould body 600 has a
moulding surface 602 with recesses 604 for receiving insulation
displacement terminal strips 112. The insulation displacement
terminal strips 112 are inserted into the recesses 604 with strip
portions 606 protruding. Additional mould bodies, such as second
mould body 608 having a moulding surface 610, are closed onto the
first mould body 600, the moulding surfaces 602, 610 defining a mould
cavity 612 between the mould bodies, the cavity being of the shape of
the shell 102. The strip portions 606 project into the cavity 612 as
shown. A third mould body 614 having a moulding surface 616 is
required to define the aperture 115 of the receptacle 114. Recesses
618 on the third mould body 614 define the steps 122 on the wall 116
25 of the receptacle 114, and fingers 620 on the first mould body 600
define the grooves 126 of the bridge member 124. Flowable plastics
material is injected into the mould cavity 612 to fill it and surround
` the strip portions 606. The terminal strips 112 fit snugly in the
recesses 604 to prevent flow of plastics material into the recesses
around the insulation displacement terminals 113. The plastics
material is solidified to form the shell 102, the strip portions 606
embedded in the shell 102.
