Telephone extension socket

A telephone extension socket comprising a housing having opposed end portions, an entry formed in one end portion to receive a telephone cable having a plurality of electrically separate wires and a socket formed in the other end portion to receive a multi-contact plug, a plurality of recesses in the housing for the respective reception of the individual wires of the telephone cable, and a plurality of electrical contacts each in the form of a resilient metal strip and each having a first end which projects into a respective recess and which has a formation serving to engage a corresponding wire of the telephone cable, and a second end projecting into the socket end for engagement with a corresponding contact of a multi-contact plug.

DESCRIPTION 
1. Field of the Invention 
This invention relates to a telephone extension socket. 
1. Background Art 
Conventionally a roving or free socket for a telephone extension cable 
comprise a generally box-like housing having a socket entry for a 
telephone jack plug on one side and a cable entry on the opposite side, 
the housing containing a separate moulding which forms a socket cavity and 
which carries a plurality of electrical contacts. The contacts extend into 
the cavity to form contact blades and one end of each of the contacts 
projects from the moulding and is soldered to a printed circuit board, 
which is also in the housing, the wires of the cable also being connected 
to the printed circuit board. Such an arrangement is expensive and time 
consuming to produce, and results in a bulky device. 
SUMMARY OF THE INVENTION 
According to the invention a telephone extension socket comprises a cable 
entry end having a plurality of recesses for the respective reception of 
individual wires of a telephone cable, and a socket end for the reception 
of a multi-contact plug, a plurality of electrical contacts each in the 
form of a metal strip and each having a first end which projects into a 
respective recess and which has a formation serving to engage a 
corresponding wire of the cable, and a second end projecting into the 
socket end for engagement with a corresponding contact of a multi-contact 
plug. 
Each formation may serve as an insulation piercing means to pierce the 
insulation of a corresponding wire. 
The socket preferably comprises two plastics mouldings, namely an inner 
moulding which defines the recesses of the cable entry end, which provides 
the socket end and which supports the metal strip contacts; and an outer 
casing which slides over the inner moulding from the cable entry end. The 
inner moulding preferably has an end wall which serves as the end wall at 
the socket end of the socket. 
The socket preferably has a cable restraint which is operative to restrain 
any tendency for the cable to be pulled out of the cable entry end. The 
restraint preferably takes the form of a tongue bendable towards the cable 
after the latter has been located in the cable entry end. The tongue may 
be formed integrally in a wall of the inner moulding by the provision in 
the wall of a line of weakness and a line which can serve as a hinge for 
the tongue, the line of weakness being ruptured to allow the tongue to be 
bent about the hinge, so that the tongue engages the cable to restrain the 
latter.

BEST MODE FOR CARRYING OUT THE INVENTION 
Referring to the drawings, a telephone extension socket comprises two 
plastics mouldings, namely an inner moulding 10 and an outer moulding or 
casing 12 in the form of a generally rectangular box-like structure which 
slides over the inner moulding 10 from the right-hand end thereof as 
illustrated in FIGS. 1 and 2. The two mouldings together form a socket 
housing 45. Location between the inner moulding 10 and outer casing 12 is 
provided by a detent tab 14 on the inner moulding 10 locating in a recess 
or slot 16 in a wall of the outer casing 12. 
The socket housing has opposed ends which are respectively a cable entry 
end 46 and a plug receiving or socket end 47. At the cable entry end of 
the housing, which is the right-hand end in FIGS. 1 and 2, the outer 
casing 12 has an end wall 18 formed with a circular cable entry hole 20 
(FIG. 4), although it will be understood that the hole 20 will be shaped 
to correspond to the cross-sectional shape of the cable to be received. At 
the other end, which is the socket end, the outer casing is formed with an 
open end through which the inner moulding is inserted. At the socket end 
of the housing a generally rectangular end wall 22 of the inner moulding 
10 has a rectangular opening providing access to the socket 24 for the 
reception of a multi-contact plug (not shown). As best seen in FIG. 2, the 
inner moulding 10 is snugly received within the outer casing 12 such that 
an end 21 of the inner moulding 10 abuts against the end wall 18 of the 
outer casing 12, and such that the end wall 22 of the inner moulding abuts 
against the open end 41 of the outer casing 12 to close the open end. 
At the cable entry end of the housing the hole 20 communicates with a 
cavity 26 in the inner moulding which leads into a plurality of spaced 
generally cylindrical recesses 28 for the respective reception of 
individual wires of a telephone cable (not shown). Into each recess 28 
projects the double barbed cable piercing blade 30 formed on an electrical 
contact 32 in the form of a metal strip. The barbs 42 engage the wall of 
the recess 28 to hold the contacts in position. Each contact 32 extends 
towards the socket end and projects into the socket 24 where it is in the 
form of a curved spring contact blade 34. There are six recesses 28 and 
six contacts 32 which are mounted in the inner moulding 10 in parallel 
spaced relationship, the contacts being separated by upstanding ribs or 
flanges 31 as best shown in FIGS. 1 and 3, which define between them 
grooves or slots 43 in which the contacts are located. 
A wall 33 of the inner moulding 10 defining the cavity 26 is formed with a 
line of weakness 36 and a reduced thickness portion 38 which serves as a 
hinge for a cable-retaining tongue 40. Downward pressure on the tongue 40 
ruptures the plastics along the line of weakness 36, allowing the tongue 
to be bent downwardly about the hinge 38 into engagement with a cable in 
the cavity 26, so as to retain the cable in the housing. In this position, 
the tip 44 of the tongue 40 engages the wall 33 to lock the tongue in 
position. 
The socket is fitted to the end of a telephone cable in the following 
manner. The outer sheathing of the cable is stripped back to reveal six 
individual insulated wires. The cable is inserted into the cable entry end 
of the inner moulding 10 through the cavity 26 (the outer casing 12 not 
yet being in position on the inner moulding 10) and the six individual 
wires are located in the respective recesses 28. In this connection it is 
preferred that the inner moulding is of a transparent plastics material so 
that the assembler can check visually that the individual wires are 
correctly positioned. The contacts 32 are then pressed into position so 
that the insulation piercing blades 30 pierce the insulation on the 
individual wires and are electrically connected to the wires. The outer 
case 12 (which has been previously threaded on the cable with the cable 
passing through the hole 20) is then slid onto the inner moulding 10, the 
end position being reached when the outer casing 12 abuts the respective 
end walls of the inner moulding, at which position the detent tab 14 
engages with snap action in the slot 16. The socket end of the socket then 
presents the six blade-like contacts 34 ready for contact with the metal 
terminals of a multi-contact plug (not shown) which is inserted into the 
socket 24. 
The invention thus provides a simple, inexpensive and small telephone 
extension socket comprising the minimum number of components and which can 
be readily assembled.