Terminal

An insulation displacement terminal includes at least one pair of wire receiving tines oriented in a plane normal to its post which is attached to a printed circuit board. An insulated wire is attached to the terminal by a pair of jaws which squeeze together in pliar-like fashion avoiding stressing the printed circuit board during the insertion.

This invention relates to an electrical wire terminal, and more 
particularly, to a terminal for making electrical interconnection to an 
insulated wire conductor by displacing the insulation and deforming the 
wire as it is inserted onto the terminal. 
Of interest are copending applications Ser. No. 779,100, filed Sept. 23, 
1985, entitled "Insulation Displacement Terminal Wire Inserton Tool and 
Method," by Ross Michael Carrell and George John Whitley and Ser. No. 
779,099, filed Sept. 23, 1985, entitled "Pneumatic Insulation Displacement 
Terminal Wire Insertion Tool," by Brian Gerard Keeler and George John 
Whitley. Both of the above copending applications are assigned to the 
assignee of the present invention. 
Terminals for receiving insulated wires directly which do not require that 
the insulation first be removed and which automatically cut into the 
insulation and deform the wire to make a reliable electrical connection, 
are in wide use and are known as insulation displacement terminals (IDTs). 
Such a terminal includes at least one bifurcated element forming a pair of 
spaced tines. The spacing between the tines is smaller than the diameter 
of the conductor of the insulated wire to be connected to the terminal. 
The terminal is designed so that when an insulated conductor is pushed 
into the space between the tines, the insulation is cut by the tines so 
that each tine makes electrical connection to the conductor. The insertion 
of the wire scrapes away any contamination on the surface of the conductor 
and the tine, deforming the conductor and bringing the fresh metal 
surfaces of the conductor and the tine together in compression. One 
example of the use of such terminals is illustrated in U.S. Pat. No. 
4,387,509. A particular terminal which might be useful in the 
above-mentioned patent is disclosed in U.S. Pat. No. 4,118,103. Another 
IDT which would be useful in the embodiment of the aforementioned U.S. 
Pat. No. 4,387,509 is a terminal known as "Quadra-mate" manufactured by 
AMP, Inc. This terminal employs a first pair of tine structures each as 
generally described above, aligned with a second mirror image pair of tine 
structures to form four parallel sets of tines for making electrical 
connection to a single wire. In the "Quadra-mate" structure, the inner 
pair of tine structures make contact with the conductor; the outer pair of 
the tine structures grip the insulation only. 
Although many IDTs do not mount on printed circuit boards, many of the 
aforementioned IDTs include terminals or post portions for securing the 
tines to a printed circuit board or other substrate. In those terminals 
that are attached to substrates (some are used in connector bodies) the 
tines extend normal to the plane of the substrate when attached to the 
substrate so that when a wire is inserted in the space defined by the 
tines for connection to the terminal, the wire at the connection is 
parallel to the substrate plane. The reason for this orientation is that 
the wires are easily pushed into the terminal in a direction normal to the 
substrate plane by manual or machine insertion with a tool from above the 
substrate. 
A problem with IDTs as presently commercially employed and illustrated by 
way of example in the aforementioned patents, is that the insertion tool 
usually applies a force of relatively large magnitude, for example, about 
20 lbs., to push the wire into the IDT slot. In a case where the substrate 
to which the IDT is secured is a thin member such as a printed circuit 
board and so forth, support is required for the substrate to withstand 
that insertion force. Additionally, when a large number of IDTs or 
components are employed on a substrate, the substrate tends to have a 
large number of apertures. These apertures tend to weaken the substrate so 
as to make support of the substrate during insertion of the wire into the 
IDTs extremely important. Without such support, the substrate may tend to 
fracture or otherwise undesirably deform, precluding proper insertion of a 
wire into the IDT. 
While the above arrangement may be acceptable for insertion of wires into 
substrates which can be placed in fixtures and jigs designed to support 
the IDTs at the insertion point, the problem becomes more acute when the 
substrate is relatively unsupported at the IDTs such as might occur, for 
example, in circuit control terminals which may be part of an electronic 
assembly such as a television receiver and not readily adaptable for such 
fixtures and jigs. 
A terminal according to the present invention for receiving and making 
electrical contact with the conductor of an insulated wire comprises an 
electrically conductive post adapted to be secured upright to a substrate 
substantially normal to the plane of the substrate. A bifurcated wire 
receiving means is electrically conductively secured to the post and is 
adapted to receive the insulated wire and make electrical conductive 
contact therewith by piercing the insulation as the wire is received. The 
wire receiving means is oriented relative to the post so that the wire, 
where received, is substantially parallel to the post and normal to the 
substrate. This permits the wire to be squeezed onto the terminal in 
pliar-like fashion avoiding a direct force on the substrate during 
insertion of the wire.

In FIG. 1, terminal 10 includes an array 12 of insulation displacement 
tines and a post 14 to which the array 12 is attached. The array 12 is a 
commercially available IDT and, as illustrated, may comprise a portion of 
an IDT Quadra-mate terminal as manufactured by AMP, Inc. However, the 
array 12 differs from the Quadra-mate terminal in that the Quadra-mate 
terminal posts for attaching the terminal to a substrate are employed 
herein for attaching the array 12 to the post 14 and are foreshortened to 
fit onto the post 14. The Quadra-mate terminal posts may be foreshortened 
before or after attachment to post 14. 
The array 12 includes four pairs of spaced parallel mating tines. Tines 20 
and 20' form a first pair spaced apart spacing 22 sufficient to compress 
and grip insulation 23 of wire 24 to isolate the contact points with the 
next adjacent pair of tines 28 and 28' from external mechanical stress as 
may be caused by movement of the attached wire. The IDT array 12 further 
includes two sets of parallel tines 28 and 28', 30 and 30' which are 
spaced so as to deform the wire, scraping away any contamination on the 
tine and conductor surfaces, and creating a gas-tight compression bond 
between the conductor and the respective tine pairs. Tines 32 and 32' are 
spaced apart in the manner of tines 20 and 20' and perform an identical 
function. Reference is made to AMP, Inc. catalog 2005-8, issued August 
1983, page 479, illustrating the IDT array 12 in more detail. Space 22 is 
sufficiently small with respect to the wire 24 so as to cut through the 
insulation, deform the wire, and make a compression bond contact with 
conductor 26 when the wire 24 is pushed into the space 22 in direction 34 
parallel to post 14. 
Tines 20 and 20' extend from wall 50 from which extends leg 36 in direction 
34. Tine set 32 and 32' extends from wall 52 from which extends leg 38 
also in direction 34. Tine sets 28, 28' and 30, 30' are interconnected by 
common wall 40 so that the array 12 may be fabricated from a single sheet 
of metal in the flat state and folded over into the configuration 
illustrated. 
Post 14 includes a rib and support member 42 and a leg 44. The support 
member 42 comprises an upper section 46 and a lower section 46'. Upper 
section 46 is a semicircular cylinder having a planar surface 48 adapted 
to abut planar walls 50 and 52. Section 46 includes a pair of apertures 54 
and 54' which closely receive respective legs 36 and 38. Lower section 46' 
is a circular cylinder which is closely spaced beneath wall 52. Depending 
from section 46' is circular cylindrical leg 44 which is dimensioned to be 
inserted in a printed circuit board or other substrate aperture to which 
the IDT terminal 10 is to be attached. Leg 44 has a length sufficient to 
extend through the substrate 16 when the substrate is a printed circuit 
board. In this case, leg 44, which may be of reduced diameter as compared 
to section 46; may be soldered at 45, FIG. 3, to a printed circuit board 
conductor (not shown) on the board undersurface. The tine array 12 is 
secured to post 14 by soldering the legs 36 and 38 and walls 50 and 52 to 
post 14. 
The longitudinal axis 60 of post 14 is normal to direction 34 and generally 
normal to the plane of the tines of array 12. In practice, the tines may 
be at a small angle relative to the normal to post 14, but this is 
acceptable. As a result, the wire 24, where attached to the tine array 12, 
however, is essentially parallel to axis 60 and normal to the plane of the 
substrate 16 to which post 14 is attached. 
A particular advantage of the terminal 10 structure, as compared to prior 
art IDTs, is that the tines may be spaced above the substrate 16, FIG. 3, 
an amount sufficient to permit a pliar-like insertion tool to embrace the 
post to provide precise location and mechanical support during the 
insertion process. Even if the post were formed of sheet metal as 
described in connection with FIGS. 4 and 5 below, the support of the 
substrate at the post insertion region is sufficient to provide the 
necessary strength and rigidity during the insertion. 
More importantly, the orientation of the tine array 12 in a horizontal 
plane, direction 34, normal to the axis 60 of the post avoids the problem 
mentioned in the introductory portion above in which the insertion tool 
tends to apply a force in direction 64 normal to the plane of the 
substrate 16. This avoids the tendency of such a normal force to bend, 
deform, or fracture the substrate unless the substrate 16 is supported in 
the region at post 14. 
In FIG. 6, a wire insertion tool for inserting wire 24 into the tines of 
array 12 may be pliar-like in construction and include a pair of jaws 70 
and 72. The jaws 70 and 72 squeeze the wire 24 and terminal 10 together in 
pliar-like fashion to push the wire 24 into the spacing 22 of the tine 
array 12. Jaw 72 may include a groove 74 for closely receiving and 
abutting the post 14 and for locating the tine array 12 relative to jaws 
70 and 72 in the horizontal plane parallel to substrate 16. In FIG. 7, the 
jaw 72 includes a projection 76 having a groove 74. Groove 74 closely 
receives and abuts the exterior surface of post 14 at sections 46 and 46'. 
Post 14 provides support for the squeezing forces exerted by jaws 70 and 
72. Thus, jaw 72 bears the brunt of the reaction forces created by the 
insertion of wire 24 into array 12 in direction 34 and transmitted by post 
14 to jaw 72. 
Jaw 70 includes three teeth 80, 82, and 84 for pushing the wire 24 into the 
tines of terminal 10. Tooth 80 is constructed to push the wire 24 in a 
region above tines 20 and 20', tooth 82 is constructed to push the wire 24 
in a region between the tines of tine sets 28, 28' and 30, 30', FIG. 1, 
and tooth 84 is constructed to push against wire 24 immediately below the 
lowest set of tines 32, 32'. 
Jaws 70 and 72 may be manually operated in pliar-like fashion for squeezing 
the wire 24 against terminal 10. By way of example, jaw 70 may be attached 
to a first arm (not shown) and jaw 72 to a second arm (not shown), with 
both arms pivoted for rotation about parallel axes. The ends of the arms 
opposite the jaws 70 and 72 may be then squeezed together or pushed apart 
according to a given implementation for operating the jaws 70 and 72 in 
the desired squeezing direction. 
By providing jaws 70 and 72 which squeeze the wire 24 onto terminal 10, 
FIG. 7, in a plane parallel to the plane of substrate 16, relatively 
negligible wire insertion forces are applied to the substrate 16 and 
therefore alleviate the potential problem of deformation or stress failure 
of the substrate 16. Thus, wire 24 can be wired point-to-point on the 
substrate 16, FIG. 7, and is vertical where attached to the mating 
terminals. 
In FIG. 4, in the alternative, an IDT terminal 105, according to the 
present invention, is shown as fabricated from a single sheet of metal. In 
this case, a single wall 50' corresponding to spaced walls 50 and 52 of 
terminal 10 FIG. 1, is attached to upper tines 107. Wall 50' terminates 
via member 111 in post 100 dimensioned to be inserted in a hole 102 in 
substrate 104. The lowermost tine set 109 terminates via member 113 in a 
second post 106 facing and parallel to post 100 somewhat similar to the 
post arrangement employed in prior art structures, e.g., the Quadra-mate 
discussed above. Member 111 includes a pair of tangs 108 and 110 and 
member 113 includes a second pair of tangs 114 (one being shown) which are 
adapted to abut against the upper surface of substrate 104 when the posts 
100 and 106 are inserted in substrate hole 102. A semicircular cylindrical 
rib 112 is formed in wall 50' to reinforce wall 50' for receiving and 
locating jaw 72, FIGS. 6 and 7. 
In FIG. 5, terminal 116 in accordance with a third embodiment of the 
present invention may include a rib structure 118 formed from wall 50" and 
comprising a pair of tangs 120 and 122. The remainder of the terminal 116 
is similar in construction to terminal 105, FIG. 4. Terminal 116, 
therefore, is also fabricated from a single sheet of metal. 
Terminals 105 of FIG. 4 and 116 of FIG. 5, each include respective ribs 112 
and 118 which have a given length in the direction parallel to the post 
axis 60. These ribs can mate with a corresponding groove (not shown) 
having the same length in the corresponding insertion tool jaw such as jaw 
72, FIGS. 6 and 7. In this case, seating of the rib 112 of terminal 109 or 
the rib 118 of terminal 116 in the groove of such a jaw would locate the 
terminal in the vertical direction parallel to axis 60 and the horizontal 
direction transverse to axis 60 normal to direction 34. While four sets of 
bifurcated wire receiving tines are shown, a terminal, according to the 
present invention, can employ at least one pair of wire receiving tines.