Wire retainer

A wire retainer is provided to pre-connectorize and position individual wires from a communications cable over a base member of a modular splice connector to facilitate the formation of a modular solderless splice. Provision is also made within the body member of the retainer for conductive probe testing of the individual wires of the communication cable.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to the splicing of communication cables, 
and in particular relates to a wire retaining device, useful for 
positioning individual wires from a multi-stranded communication cable in 
separated predetermined position over a modular splicing connector base 
member. Such modular splice connectors are known in the art from U.S. Pat. 
No. 3,708,779 to D. J. Enright et al assigned to Minnesota Mining and 
Manufacturing Company. 
2. Description of the Prior Art 
In the communication industry, it is desirable to inspect and test 
multi-wire communication cable before it is sent out into the field for 
assembly into a communication network. This result can be achieved by 
pre-terminating or pre-connectorizing the cable ends which permits cable 
testing in the cable factory or warehouse. In the field, these terminated 
ends can be joined to produce the completed cable-splice assembly. 
Applicants' invention provides a means for achieving desirable 
pre-connectorizing and testing of communication cables while providing a 
means for subsequent modular splice assembly in the field. 
SUMMARY OF THE INVENTION 
The object of this invention is to provide means for pre-connectorizing a 
length of telecommunication cable in a fashion which permits both testing 
and rapid field splicing of the cable. 
The retainer device consists of an elongate rectangular body member made 
from an insulating material such as a thermoplastic resin. This 
rectangular body member has a planar channel with alignment posts at each 
end. The base of a modular splicing connector is placed over the alignment 
post, thus positioning it in the channel. 
The body member has a series of spaced projections, such as loop 
structures, which are formed along the back edge of the upperside of the 
body member. These projections separate and align the wires of the cable 
as they are laid in the wire retaining channels defined by the spaced 
projections. A complimentary series of spaced projections are located 
along the front edge of the upper surface of the body member. These 
projections which may be rectangular in shape define wire crimping 
channels. In operation, isolated, individual wires of the communication 
cable are laid transversely across the body member and lie in the wire 
retaining channels defined by the spaced projection or loop structures on 
the back edge of the body member and in the wire crimping channels defined 
by the spaced projections on the front edge of the body member. 
A series of cap retaining anchor posts may be provided on the rectangular 
elements which form the wire crimping channels to align and anchor a cap 
member which is placed in mating relationship over the wire crimping 
channels. 
In every wire crimping channel there is a strain relief recess. This recess 
provides the space into which an individual wire is forced when the cap 
member is installed. This recess may extend completely through the body 
member to form a test access hole connecting the upper and lower surfaces 
of the body member. This hole, which may be rectangular in shape, provides 
an access port for electrical conductive test probes that may be inserted 
into the crimping fixture to contact the individual wires through the 
lower surface of the body member. 
During assembly, the cap member is pressed down onto the body. The anchor 
posts assist in the alignment of the cap member over the body member. 
Triangular shaped wire pushers formed in the cap member are located over 
the access holes in the body member. These pushers bend and force a short 
section of each wire into the access hole to mechanically lock the wire 
between the cap member and the retainer body member. The anchor posts 
which extend through cooperative holes in the cap member after the cap is 
mated to the body member, are cold-staked during the assembly process. 
This cold-staking process deforms the anchor posts into engagement with 
the holes of the cap member, thus securing the cap member to the body 
member. 
To prevent these anchored wires from lifting out of the spaced projections 
on the front side of the retainer body during storage or while the cable 
is being handled, a strand of wire is inserted through these spaced 
projections which secure the strands of communication wire in the 
retaining channels.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The retainer body member as shown and described is adapted to splice 25 
pairs of wires from a communication cable. This number is a standard of 
the U.S. communication industry; however, it is clear that the device 
according to this invention can be adapted to other cable standards. 
The wire retainer body 5 has an elongated planar channel. The splicing 
module base 7 is aligned in this channel by alignment posts 6 on the body 
which cooperate with openings in the ends of the base. The back or wire 
receiving edge 8 of the retainer body has a multiplicity of spaced 
projections shown as wire retaining loops 14 formed along the upper 
surface of this edge. These loops coact with spaced projections shown as 
rectangular members 15 formed along the front edge 9 or crimping area of 
the body member to define wire channels which accept the telecommunication 
wires 18 as shown in FIG. 2. 
In FIG. 2 the wire retainer is shown in the completely assembled 
configuration. A pair of telecommunication wires 18 have been placed 
transversely across the body member 5 and the cap member 23 has been 
cold-staked into position, thus securing the telecommunication wires to 
the body member. 
Spaced projections shown as loop structures 14 are shown in cross-section 
on FIG. 3. Each loop structure consists of an arch shaped member, one end 
of which is anchored at the back edge 8 of the upper surface of the body 
member 5. The other end of the arch shaped member is attached to a bar 
structure 20, which runs parallel to and in the plane of the body member. 
Successive arch shaped members provide wire retaining channels 16 which 
receive the individual wires from the multi-stranded cable. These 
individual wires 18 are laid transversely across the body member as shown 
in FIG. 3. 
When assembly is completed, a length of wire 21 (FIG. 4) is inserted 
through the loop structures lengthwise with respect to the body member 14 
to prevent telecommunication wires 18 from lifting away from the retainer 
body member 5. This retaining wire 21 traps both the aligned 
telecommunication wires and the base member of the modular splice. 
Although the spaced projections which define these wire retention channels 
have been shown and described as loop structures, other topologically 
equivalent structures may be used. 
The crimping action of the cap member is shown sequentially in FIGS. 3 and 
4. An individual wire 18 from a cable is placed transversely across the 
wire retainer body member in channels defined by the loop structures 14 on 
the back edge of the body and the spaced rectangular projections 15 on the 
front edge of the body. The cap member 23 has individual triangular pusher 
members 24 which are positioned to align one directly over each access 
hole 26. When this cap member is pressed down over the anchor posts 27, 
wires 18 are forced to enter access holes 26. When the cap member is fully 
seated, the anchor posts 27 which extend above the surface of the cap 
member 23 are cold-staked to prevent the cap from moving. This process 
deforms the anchor posts and causes them to tightly engage the holes in 
the cap member. During the crimping and staking operation, the wire end 28 
is sliced off by a cut-off knife before the cap member is fully seated. 
This sequence allows the final travel of the cap member to withdraw the 
free end of wire 18 slightly under the edge of cap member 23, as the wire 
is deformed into the access hole. 
In summary, a typical assembly sequence would include locating the body 
member in the splicing head of a hydraulic or pneumatic splicing machine. 
Next, a base portion of a modular splicing connector would be laid in 
place in the center channel of the body member. Then pairs of wires from a 
telecommunication cable would be isolated and laid across the retainer 
base utilizing standard wire handling procedures. The cap member would 
then be placed over the extended anchor posts and a hydraulic or pneumatic 
crimping tool would engage in a three-stage action to complete the 
assembly of the unit. The crimping tool will have means for slicing off 
the free ends of the wires which extend out of the wire channels at front 
edge 9 of the body member. The tool will also have provision for 
cold-staking the anchor posts extending through the cap member. As the 
crimping tool is activated, contact is first made between the wire cut-off 
blade and an individual wire which lies in the wire channel. As the 
cut-off blade contacts a wire, the cap is pressed down to slightly 
displace the wire into the access holes. Typically, the cut-off tool will 
completely sever the wire before the crimping cap is completely seated. 
After the wire is severed, continued motion of the crimping tool causes the 
crimping cap to be completely seated. During this seating action, the 
triangular shaped wire pushers 24 on the cap member 23 bend each wire 18 
and force it into the test access hole 26 in the body member 5. This 
action deforms the wire and its insulation, physically locking and binding 
the wire end in place. 
If electrical testing is desired, a sharp insulation piercing conductive 
probe device 29 can be inserted in the base assembly fixture and will make 
electrical contact with the wires through the access hole. Such conduction 
probe assemblies are known in the art from U.S. Pat. No. 3,699,501 to 
Enright et al, assigned to Minnesota Mining and Manufacturing Company, the 
assignee of this invention. The conductive probe assembly may pierce the 
insulation of the wire located in the access hole before or after the wire 
is cut off. If conductive probe testing is accomplished before the wires 
are severed, then the assembly process can be halted and corrective 
measures taken before the wires are severed. 
The triangular shape of the pusher will withdraw the cut end of the wire 
from the cut-off blade during the crimping cap seating phase. This will 
electrically isolate this wire for test purposes. However, to ensure 
positive electrical isolation from the cut-off blade, it is desirable to 
coat the surface of the cut-off blade with a wear-resistant and 
non-conductive coating such as aluminum oxide or zirconium oxide. The 
final phase of the crimping operation is cold-staking of the anchor posts 
27 which extend beyond the upper surface of crimping cap 23 through 
alignment holes 25. When the cap is completely seated and cold-staked into 
position, the body member and its associated cable will be removed from 
the crimping tool. The final assembly operation consists of insertion of a 
length of wire 21 through the retaining loops 14 of the body member to 
prevent the telecommunication wires 18 from lifting out of the front end 
of the body, and thus to trap the splicing module base 7 in the planar 
channel of the body member. 
The fully completed retainer assemblies are covered for protection during 
storage and shipment. When the completed assembly is used in the field, 
the protective cover is removed and the retainer body placed in a portable 
splicing unit. The field splicing operation mates telecommunicaton wires 
18 with the corresponding wire pairs of the complimentary cable assembly. 
The splicing operation mates the modular splice base portion located in 
the retainer body with a splice module on an adjoining cable. This 
operation cuts the telecommunication wires 18 free from the retainer 
assembly which is then removed by withdrawing wire 21 from the retaining 
loops 14. The body member which carries the punctured and severed wires is 
removed from the completed splice and discarded.