Electrical connectors

A stuffer cap for an insulation displacement connector comprises a base, a pair of end walls, a pair of side wall and intermediate walls parallel to the end walls. The end walls each have a recess in which is arranged an outwardly extending latch which has a contact point for engaging with a ledge on the connector housing, a contact surface and an engaging point which snaps into a recess in the housing to retain the cap in position. In one embodiment, recesses in the edges of the side walls are replaced by apertures enabling removal of wires with the stuffer cap. In a further embodiment hooks are provided in the recesses which are resilient in the direction of wire insertion and rigid in the direction of wire extraction. In a further embodiment the latch extends inwards and engages with the ledge adjacent that on which the outwardly extending latch engages.

RELATED APPLICATIONS 
This application claims priority to U.K. 93 08954.8 filed 30 Apr. 1993. 
FIELD OF THE INVENTION 
This invention relates to electrical connectors and in particular to 
stuffer caps which are used with insulation displacement connectors. 
BACKGROUND TO THE INVENTION 
An insulation displacement connector comprises a number of insulation 
displacement contacts mounted in a housing. Insulated wires are attached 
to the contacts by forcing parallel blades of the contact apart. The inner 
edges of the blades cut into the plastic insulation and establish 
electrical contact between the wire and the contact. 
In many cases the wires are inserted using a punch-down tool which is 
placed on the housing over the terminal to be connected and used to apply 
the necessary force to engage the wire in the contact. The tool may 
include a cutting device for neat termination of the wire. Punch-down 
tools are well known in the art. 
In other cases it is desirable to use stuffer caps to establish connections 
between wires and contacts. Stuffer caps may also be used as dust 
protectors on assembled connectors. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide an improved stuffer cap. 
It is a further object of the invention to provide an improved latching 
mechanism for securing the stuffer cap to the insulation displacement 
connector body. 
It is a still further object of the invention to provide for removal of 
wires engaged with contacts using a stuffer cap. 
It is another object of the invention to provide for removal of wires 
engaged with insulation displacement contacts before the stuffer cap is 
applied to the connector body. 
In accordance with a first aspect of the invention a stuffer cap is 
provided for use with an insulation displacement connector. The connector 
has a number of insulation displacement contacts and a body having 
recesses. The stuffer cap comprises a body having a top, an opposed pair 
of side walls, an opposed pair of end walls and one or more intermediate 
walls disposed substantially parallel to or between the pair of end walls. 
A retaining means is provided for retaining the stuffer cap in position on 
the connector and comprises a latch means arranged on one or both of the 
end walls for engagement in a respective recess in the body. 
In accordance with a second aspect of the invention a stuffer cap is 
provided for use with an insulation displacement connector. The connector 
has a number of insulation displacement contacts and a body having 
recesses. The stuffer cap comprises a body having a top, an opposed pair 
of side walls, an opposed pair of end walls and one or more intermediate 
walls disposed substantially parallel to or between the pair of end walls. 
A retaining means is provided for retaining the stuffer cap in position on 
the connector. A plurality of apertures are provided in the side walls 
which are arranged such that axes of opposed pairs of apertures are 
aligned with the end walls and the intermediate walls. The apertures are 
arranged towards free edges of the side walls below the lowermost limit of 
the end and intermediate walls. 
In accordance with a third aspect of the invention a stuffer cap is 
provided for use with an insulation displacement connector. The connector 
has a number of insulation displacement contacts and a body having 
recesses. The stuffer cap comprises a body having a top, an opposed pair 
of side walls, an opposed pair of end walls and one or more intermediate 
walls disposed substantially parallel to or between the pair of end walls. 
A retaining means is provided for retaining the stuffer cap in position on 
the connector. The free ends of the side walls have recesses therein. 
Opposite pairs of recesses are aligned with the end and intermediate 
walls. The recesses have sides having a hook means extending therefrom, 
each hook means being resilient to force applied in a direction extending 
from the free ends of the side walls to the top, but rigid to force 
applied in an opposite direction. 
The above and other features of the invention including various and novel 
details of construction and combination of parts will now be more 
particularly described with reference to the accompanying drawings and 
pointed out in the claims. It will be understood that the particular 
electric connectors embodying the invention are shown by way of 
illustration only and not as a limitation of the invention. The principles 
and features of this invention may be employed in varied and numerous 
embodiments without departing from the scope of the invention.

DESCRIPTION OF BEST MODE 
Insulation displacement connectors of the type shown in FIG. 1 are sold by 
MOD-TAP Limited of Vincent Avenue, Southampton, England under the trade 
mark KATT and are described in detail in copending International 
Application Publication No: WO92/22941 the contents of which are 
incorporated herein by reference. For the purposes of understanding the 
present invention it is necessary to understand that the connector housing 
10 has a plurality of teeth 12 which retain the insulation displacement 
contacts. Wires are inserted through slits 14 defined between adjacent 
teeth. The longitudinal faces 16 of the teeth which oppose one another 
have a ledge 18 around their periphery. Each insulation displacement 
contact has a pair of opposed tynes, one tyne of each pair being retained 
in a recess in each tooth partly defined by the ledge 18, the other of the 
pair being retained in the adjacent recess. 
Referring now to FIGS. 2 to 6, the stuffer cap is intended to sit on top of 
the teeth of the insulation displacement connector. The cap may be used 
both for wire insertion and as a dust cap once in position. The cap 
comprises a body 20 having a substantially flat top portion 22, two 
depending side walls 24, 26 and two depending end walls 28,30. In the 
embodiment of FIG. 2, the lower free ends of the side walls have a series 
of U shaped recesses 32 which, in position on the connector, are aligned 
with the slits 14 to enable a connected wire to protrude through the side 
wall of the stuffer cap. 
As can be seen from FIGS. 5, 6, and 7, the interior of the stuffer cap has 
a plurality of parallel walls 34 which extend between the centres of pairs 
of recesses in the side walls. The end walls 28, 30 constitute two such 
walls. The walls each include a slot 36 in their mid portions. The slots 
are offset, alternately on opposite sides of the longitudinal axis 38 of 
the stuffer cap and correspond to the positions of the insulation 
displacement contacts in the housing 10. 
The end walls 28,30 have a recess 40 at their upper ends (FIG. 6) in which 
is located a latch 42. As can be seen from FIG. 4, the latch has an 
outwardly extending bead portion 44 having an outer contact point 46 and a 
latching point 48 arranged at opposite ends of an engaging face or contact 
area 50. 
In use, wires to be connected are laid across slits 14 in the insulation 
displacement connector, above the contacts with which they are to be 
engaged. The stuffer cap is placed over the connector and rests with the 
recesses 32 each surrounding a wire. The end walls 28, 30 and the other 
lateral walls 34 push the wires into the insulation displacement contacts. 
When pushed fully home, the slots 36 in the walls are positioned over a 
respective contact. 
As the cap is pushed towards the insulation displacement connector, the 
contact points 46 of the latches on the end walls will engage with the 
respective ledges 18 on teeth of the housing. The ledges will force the 
latch beads 44 towards one another against their natural resilience until 
the contact points have passed the lower edge of the ledge. The engaging 
face 50 of the bead will then slide over the lower edge of the ledge until 
eventually latching point 48 slides underneath the ledge and extends with 
its own resilience into the recess defined by the ledge, holding the 
stuffer cap snapped into position on the insulation displacement 
connector. 
Referring to FIG. 8, the embodiment illustrated is similar to that 
described except that the recess 32 have been blocked off and apertures 52 
formed in their place. 
To insert wires into the insulation displacement connector the wires are 
first fed through a pair of opposed apertures 52 in the side walls and 
then the stuffer cap is forced onto the housing. As the wires remain 
enclosed by the stuffer cap they can be removed from the insulation 
displacement contacts by removal of the stuffer cap. 
The embodiment of FIG. 9 enables removal of wires from contacts 
irrespective of whether they have been engaged with the insulation 
displacement contacts using the stuffer cap, for example using a wire 
connection tool. The construction is similar to that of the embodiment of 
FIGS. 2 to 7, however, a latching mechanism is attached to the walls of 
the recesses 32 on the side walls. The latch comprises a pair of resilient 
hook members 60,62. One on each side wall of the recess. The hook members 
are resilient when force is applied in a direction towards the interior of 
the cap (arrow A in FIG. 9) and when force is applied in the opposite 
direction. 
The stuffer cap is applied in the same manner as described with respect to 
FIGS. 2 to 7 and the hook members 60,62 will bend back against their 
natural resilience and spring back underneath the wire. As the hooks are 
rigid when force is applied from the opposite direction they will act to 
disconnect wires from their contacts when the stuffer cap is removed. This 
embodiment may be used to remove wires which are already in position on 
the insulation displacement connector. 
Turning now to FIGS. 10 to 16 there is illustrated an alternative 
embodiment to the embodiment of FIGS. 2 to 7. In the following description 
the same references are used, increased by 100. Where elements of the 
drawing are not described they are the same as the FIG. 2 to 7 embodiment. 
In the FIG. 10 to 16 embodiment the latch 142 has been reversed, such that 
snap bead 144 extends inwardly towards the interior of the stuffer cap 
body. The recesses in the end walls 128, 130 are replaced by rectangular 
apertures 129, 131, the walls 128, 130 being continuous. As can be seen 
from FIG. 16, the snap beads 144 are rectangular extending from the inner 
faces of the end walls 128, 130 above the lower wall of aperture 140 in 
their ends. 
Location of the stuffer cap on the insulation displacement connector is 
similar to that described with respect to FIGS. 2 to 7. However, it will 
be appreciated that the snap bead will latch with the ledge 18 of the 
connector opposite to that with which the outwardly extending latch 
engages. 
In addition, each of the end walls and the internal parallel walls 134 
carry curved grooves 160 on their lower ends. These grooves are located on 
each side of the end walls 128, 130 and the two internal walls 134, one on 
each side of the centre axis 138 spaced equidistant therefrom. Thus, each 
of the four walls carry four grooves. FIGS. 15 and 16 show how these 
grooves extend from the free ends of the walls to just after the beginning 
of the tapered portions indicated by line 162. The grooves assist in the 
location of the stuffer cap over the wire clamping features of the 
connector, by, for example, engaging with corresponding ribs protruding 
from the walls on either side of the slits 14 shown in the connector of 
FIG. 1. 
The embodiments of FIGS. 8 and 9 may be incorporated into the FIGS. 10-16 
embodiment in the same way as described with respect to the FIGS. 2 to 7 
embodiment.