Strand cable press-contacting terminal

A strand cable press-contacting terminal primarily comprising: a pair of fore and aft press-contacting pieces are arranged longitudinally in the terminal fitting; an even number of twisted wires are aligned in the first external layer of said cable; and wherein said pair of fore and aft press-contacting pieces are spaced each other to the distance value which is obtained by multiplying a quarter of the wire strand pitch by an odd number n. Further, this invention may be a strand cable press-contacting terminal comprising: more than two pairs of press-contacting pieces are provided longitudinally in the terminal fitting; said terminal is used for plural kinds of strand cables differed in strand pitch; an even number of twisted wires are aligned in the first external layer of said each cable; and, wherein the each distance between said more than two pairs of press-contacting pieces is decided on the same value as a quarter of said each cable strand pitch being multiplied by an odd number n.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to press-contacting terminals and more particularly 
to press-contacting terminals having an appropriate contact area so as to 
connect reliably a strand cable thereto, wherein an even number of twisted 
wires are aligned in the first external layer of the cable having totally 
an odd number of wires. 
2. Description of the Prior Art 
Conventional press-contacting terminals for strand cables are illustrated 
in FIGS. 17 and 18. A press-contacting terminal 27 (or 28) has each pair 
of fore and aft press-contacting pieces 3,4 (or 29, 30) formed by raising 
up tab portions struck from a bottom wall of the terminal as shown in FIG. 
17 or by inwardly bending tab portions struck from side walls of the 
terminal as shown in FIG. 18. A terminal contacting member 31( or 33) for 
a corresponding other terminal is formed forward to the fore 
press-contacting pieces 3 (or 29) and an insulation covered cable clamping 
portion 32(or 34) is formed in the back of the aft press-contacting pieces 
4 (or 30). The interval L of the fore and aft press-contacting pieces 3,4 
(or 29, 30) is decided in consideration of the over all length of the 
terminal 27(or 28) or a space laying between the terminal contacting 
member 31(or 33) and the insulation-covered cable clamping portion 32(or 
34). 
The strand cable 2 is pressed downward into a slot 35(or 36) formed between 
the right and left press-contacting pieces 3,3 or 4,4 (or 29,29 or 30,30). 
In FIG. 19, there is illustrated an example of wire press-contacting 
patterns in respect of a press-contacting terminal 27. 
The each pair of aft press-contacting pieces 3,4 (or 29, 30) forms an 
upwardly open notch for receiving the insulation-covered strand cable, the 
notch converging downwardly and having thin edges to afford a cutting 
section for shearing through the cable insulation. 
Further, FIGS. 20A to 20C show respectively strand cables 2,6,37 to make 
electric connection with terminals by press-contacting. In regard to the 
cables such as the type number CAVS0.5SQ (seven wires) or AVSS2SQ (thirty 
seven wires), around a core wire 1.sub.0, 5.sub.0, 38.sub.0), an even 
number of wires 1,5, 38 are circularly aligned in one or a plurality of 
layers. The strand cables 2, 6, 37 have, in each of the first external 
layers, six, twelve, eighteen wires respectively. 
SUMMARY OF THE INVENTION 
However, in the above mentioned previously known press-contacting 
structures in respect of the strand cables, every of the fore and aft 
press-contacting pieces 3,4 (or 29, 30) can, as shown in FIG. 19, make 
contact with, in some cases, only one wire in the first external layer of 
the strand cable at each of the right and left press-contacting pieces, 
which causes a disadvantage of a less contacting area to have an 
unreliable electric-continuity effect. 
This invention aims, without engendering the disadvantage of the above 
mentioned previously known press-contacting structures, to provide a 
press-contacting terminal for a strand cable, wherein each pair of fore 
and aft press-contacting pieces 3,4 (or 29, 30) can make appropriately 
contact with wires 1,5, 38 so as to have a reliable electric continuity 
effect. 
To achieve the aforementioned object, a strand cable press-contacting 
terminal of this invention primarily comprises: a pair of fore and aft 
press-contacting pieces are arranged longitudinally in the terminal 
fitting; an even number of twisted wires are aligned in the first external 
layer of the cable; and, wherein the pair of fore and aft press-contacting 
pieces are spaced each other to the distance value which is obtained by 
multiplying a quarter of the wire strand pitch by an odd number n. 
Further, this invention may be a strand cable press-contacting terminal of 
the invention comprises: more than two pairs of press-contacting pieces 
are provided longitudinally in the terminal fitting; the terminal is used 
for plural kinds of strand cables differed in strand pitch; an even number 
of twisted wires are aligned in the first external layer of the each 
cable; and, wherein the each distance between the more than two pairs of 
press-contacting pieces is decided on the same value as a quarter of the 
each cable strand pitch being multiplied by an odd number n. 
Referring to the operation of the above invention, the wires aligned in the 
first external layer of each of the strand cable have a 90.degree. 
phase-shift difference between in one-quarter and one-half strand pitch 
proceeding sections. If a plurality of the wires are positioned vertically 
in line at both sides of the strand cable n a one-quarter strand pitch 
proceeding section, one of or at least one of the wires is positioned at 
both sides of the strand cable in a one-half strand pitch proceeding 
section. Accordingly, if the fore and aft press-contacting pieces are 
spaced to the distance of a quarter of the wire strand pitch (as a half 
minus a quarter equals a quarter), at least either pair of the fore and 
aft press-contacting pieces makes contact with a plurality of the wires at 
both sides of the strand cable to obtain a larger continuity area. And, 
the alignment of the wires in the first external layer in a three-quarters 
strand pitch proceeding section is similar to the one in a one-quarter 
strand pitch proceeding section. 
Moreover, for a plurality of strand cables differed in strand pitches, more 
than two press-contacting pieces are provided so as to be spaced as 
mentioned above according to each strand pitch. It can provide a 
press-contacting terminal with larger continuity areas, which is used 
commonly for a plurality of strand cables differed in strand pitches.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
In FIGS. 1A to 2C, there is shown a strand cable 2 composing of seven wires 
1 (six wires in an external layer). When the strand pitch is 10 mm in 
length, in FIGS. 1A and 1B, A1--A1 section of the one-half strand pitch 
proceeding section (5 mm proceeding section) and A2--A2 section of the one 
strand pitch proceeding section (10 mm proceeding section) have the same 
wire alignment (which is shown in FIG. 2A) as that of the front end of the 
strand cable, which is illustrated in FIG. 1A. In these sections, each 
couple of wires 1.sub.1,1.sub.2 are aligned vertically at each side of the 
strand cable. Precisely speaking, the wire alignment of A2--A2 section is 
shifted by 180.degree. in phase from that of A1--A1 section. And, both of 
B1--B1 section of the one-quarter strand pitch proceeding section (2.5 mm 
proceeding section) and B2--B2 section of the three-quarters strand pitch 
proceeding section (7.5 mm proceeding section) have one 1.sub.3 of the 
wires at both sides of the strand cable, which is shown in FIG. 2B. 
And, both of C1--C1 section of the three-eighths strand pitch proceeding 
section (3.75 mm proceeding section) and C2--C2 section of the 
seven-eighths strand pitch proceeding section (8.75 mm proceeding section) 
have each couple of wires 1.sub.2,1.sub.3 at both side portion of the 
strand cable, wherein the each couple of wires are aligned in parallel and 
unsymmetrical to the other couple of wires and inclined to the center 
vertical line of the strand cable as shown in FIG. 2C. And, both of D1--D1 
section of the eighth-strand pitch proceeding section (1.25 mm proceeding 
section) and D2--D2 section of the five-eighths strand pitch proceeding 
section (6.25 mm proceeding section) have each couple of wires 
1.sub.2,1.sub.3 at both sides of the strand cable, wherein the each couple 
of wires are inclined symmetrically (not illustrated) to those which are 
shown in FIG. 2C. 
Now, in regard to a strand cable press-contacting terminal according to 
this invention, at least a pair of fore and aft press-contacting pieces 
3,3 and 4,4, for example, which are shown in previously-known terminals 
illustrated in FIGS. 17 and 18, should always be able to make contact with 
a plurality of wires 1 at each side portion of the strand cable to have an 
appropriate electric continuity. To achieve the above mentioned effect, 
when a strand pitch, for example, is 10 mm in length, the fore and aft 
press-contacting pieces 3,4 are spaced by 2.5 mm, that is a quarter of the 
wire strand pitch length. A general formula that determine an interval L 
of the fore and aft press-contacting pieces 3,4 according to a wire strand 
pitch P, is as follows; 
EQU L=P/4.times.n (n is an odd number) 
That is, as shown in FIGS. 3A and 3B, when the fore press-contacting piece 
3 is positioned at A1--A1 section of a one-half strand pitch proceeding 
section (5 mm proceeding section), the aft press-contacting piece 4 is 
located at B2--B2 section of a three-quarters strand pitch proceeding 
section (7.5 mm proceeding section). As a result, the pair of fore 
press-contacting piece 3,3 can, as shown in FIG. 4A, make contact with 
each couple of wires 1.sub.1, 1.sub.2 to have a larger continuity area. 
While, the pair of aft press-contacting piece 4,4, as shown in FIG. 4B, 
make contact with only each one wire 1.sub.3, wherein the wire alignment 
is shifted by 90.degree. in phase in comparison with the one FIG. 4A. 
Further, as shown in FIGS. 5A and 5B, when the fore press-contacting piece 
3 is positioned at B1--B1 section of a one-quarter strand pitch proceeding 
section (2.5 mm proceeding section) and the aft press-contacting piece 4 
is located in A1--A1 section of a one-half strand pitch proceeding section 
(5 mm proceeding section), the pair of fore press-contacting piece 3,3 
can, in contrast with that of FIG. 4 and as shown in FIG. 6A, make contact 
with only each one wire 1.sub.3. While, the pair of aft press-contacting 
piece 4,4, as shown in FIG. 6B, make contact with each couple of wires 
1.sub.1, 1.sub.2. B1--B1 section in FIG. 5B is shifted by 180.degree. in 
phase in comparison with B2--B2 section in FIG. 3B. 
Moreover, as shown in FIGS. 7A and 7B, when the fore press-contacting piece 
3 is positioned at C1--C1 section of a three-eighths strand pitch 
proceeding section (3.75 mm proceeding section) and the aft 
press-contacting piece 4 is located at D2--D2 section of a five-eighths 
strand pitch proceeding section (6.25 mm proceeding section), the pair of 
fore press-contacting piece 3,3 can, as shown in FIG. 8A, make contact 
with each couple of wires 1.sub.2, 1.sub.3 which are aligned in parallel 
to each other as inclining to a vertical line (wherein, the contacting 
force is larger in respect of the wire 1.sub.2 and smaller in respect of 
the wire 1.sub.3). While, the pair of aft press-contacting piece 4,4, as 
shown in FIG. 8B, make contact similarly with a couple of wires 1.sub.1, 
1.sub.3 shifted by 90.degree. in phase in comparison with that of FIG. 8A, 
which enables to get a larger continuity area. 
In FIGS. 9 to 14, there is shown an example of a strand cable 6 composing 
of nineteen wires 5 (twelve wires in the first external layer) which is 
connected to a press-contacting terminal. When the strand pitch is 10 mm 
in length, as shown in FIGS. 9A and 9B, and the fore press-contacting 
piece 7 is positioned at A1'--A1' section of a one-half strand pitch 
proceeding section (5 mm proceeding section), the aft press-contacting 
piece 8 is located at B2'--B2' section of a three-quarters strand pitch 
proceeding section (7.5 mm proceeding section). As a result, the pair of 
fore press-contacting pieces 7,7 can, as shown in FIG. 10A, make contact 
with each three wires 5.sub.1 to 5.sub.3 to have a larger continuity area. 
While, the pair of aft press-contacting piece 8,8, as shown in FIG. 10B, 
make contact with only each one wire 5.sub.5, wherein the wire alignment 
is shifted by 90.degree. in phase in comparison with that of FIG. 10A. 
Further, as shown in FIGS. 11A and 11B, when the fore press-contacting 
piece 7 is positioned at B1'--B1' section of a one-quarter strand pitch 
proceeding section (2.5 mm proceeding section) and the aft 
press-contacting piece 8 is located at A1'--A1' section of a one-half 
strand pitch proceeding section (5 mm proceeding section), the pair of 
fore press-contacting piece 7,7 can, as shown in FIG. 12A, make contact 
with each one wire 5.sub.5. While, the pair of aft press-contacting piece 
8,8, as shown in FIG. 12B, make contact with each three wires 5.sub.1 to 
5.sub.3. B1'--B1' section is shifted by 180.degree. in phase in comparison 
with B2'--B2' section in FIG. 10B. 
In FIGS. 13A and 13B, the fore press-contacting piece 7 is positioned at 
C1'--C1' section of a three-eighths strand pitch proceeding section (3.75 
mm proceeding section) and the aft press-contacting piece 8 is located at 
A1'--A1' section of a five-eighths strand pitch proceeding section (6.25 
mm proceeding section). The pair of fore press-contacting piece 7,7 can, 
as shown in FIG. 14A, make contact with each three wires 5.sub.3 to 
5.sub.5 aligned with an inclination to a perpendicular. And, the pair of 
aft press-contacting piece 8,8, as shown in FIG. 14B, similarly make 
contact with each three wires 5.sub.1, 5.sub.5, and 5.sub.6. As a result, 
an appropriate electric continuity is achieved. 
As mentioned above, a section in which only each one wire is positioned at 
each side portion of the strand cable and a section in which a plurality 
of wires are positioned at each side portion of the strand cable comes 
alternately at the every quarter strand pitch (90.degree. in phase). 
Therefore, a general formula that determines an interval L of the fore and 
aft press-contacting pieces 3,4 or 7,8 according to a wire strand pitch P, 
is set up as follows; 
EQU L=P/4.times.n (n is an odd number) 
And, if an interval L of the fore and aft press-contacting pieces 3,4 or 
7,8 is determined to a quarter or three quarters of the strand pitch or so 
on, at least one of the fore and aft press-contacting pieces 3,4 (or 7,8) 
can make contact with a plurality of wires 1 (or 5) to get an appropriate 
electric continuity. 
In FIGS. 15 and 16, in regard to press-contacting terminals 15,16, 
according to the general formula to determine an interval of the fore and 
aft press-contacting pieces 3,4; L=P/4.times.n (n is an odd number), three 
right and left pairs of fore, middle, and aft press-contacting pieces 9 to 
11 or 12 to 14 are positioned so as to make contact with every of two 
kinds of strand cables differed in strand pitches to get an appropriate 
electrical continuity. 
For example, when one press-contacting terminal 15 (or 16) is utilized for 
both of a strand cable with a 10 mm strand pitch and another strand cable 
with a 24 mm strand pitch, an interval L1 of the fore and middle 
press-contacting pieces 9,10 (or 12,13) is determined to 2.5 mm, that is a 
quarter of 10 mm, and an interval L2 of the fore and aft press-contacting 
pieces 9,11 (or 12,14) is determined to 6 mm, that is a quarter of 24 mm. 
Thereby, the strand cable with 10 mm strand pitch can have a larger 
contact area pressed to at least one of the fore and middle 
press-contacting pieces 9,10 (or 12,13) and the strand cable with 24 mm 
strand pitch also can have a larger contact area pressed to at least one 
of the fore and aft press-contacting pieces 9,11 (or 12,14). 
In FIG. 15, in respect of a strand cable press-contacting terminal 15, 
three pairs of fore, middle, and aft press-contacting pieces 9 to 11 are 
formed by rising up struck portions of a base plate 19 located between a 
front contact member 17 for another terminal and a rear clamping portion 
18 for a insulation-covered cable. A projecting portion 22 formed on a 
side end of each pair of the press-contacting pieces 9 to 11 are engaged 
and fixed to a vertical slits 21 formed in each side plate 20. 
In FIG. 16, in respect of a strand cable press-contacting terminal 16, two 
pairs of fore and middle press-contacting pieces 12, 13 are formed by 
cutting out and rising up a base plate portion 23 and a pair of aft 
press-contacting pieces 14 are formed by bending inwardly aft ends of both 
side plates 24. 
The above mentioned press-contacting terminals 15,16 can be utilized for 
every of two kinds of cables differed in strand pitches. It is noted that, 
in regard to the pairs of the press-contacting pieces 9 to 11 (12 to 14), 
the number of pairs of the press-contacting pieces are not limited to 
three. More than three pairs of press-contacting pieces positioned 
longitudinally according to intervals L1, L2, L3, and so on that are 
determined by the above mentioned general formula can be arranged in a 
press-contacting terminal so that the press-contacting terminal can be 
commonly utilized also for more than two kinds of strand cables differed 
in strand pitches. 
Accordingly, in respect of a strand cable press-contacting terminal 
according to this invention, an interval L of the fore and aft 
press-contacting pieces is determined in accordance with the formula; 
L=P/4.times.n (P; a strand pitch, n; an odd number). Therefore, whichever 
longitudinal part of the strand cable makes press-contact with the 
press-contacting pieces, at least one pair of fore and aft 
press-contacting pieces can always be able to make contact with a 
plurality of wires at each side portion of the strand cable to have a 
larger electric continuity area. As a result, it can avoid the 
above-mentioned drawback that every of fore and aft press-contacting 
pieces has a small contact area to a strand cable in some press-contacting 
positions of the strand cable, which achieves always an appropriate 
electric contact and an improved reliable electric connection. 
Further, as more than two press-contacting pieces are provided 
longitudinally in the terminal at the interval L; L=P/4.times.n (P; a 
strand pitch, n; an odd number), corresponding to various kinds of strand 
cables differed in strand pitches, one press-contacting terminal can 
connect whichever of various kinds of strand cables. And, it avoid a 
complicated works that, corresponding to various strand pitches, a plural 
kinds of press-contacting terminal should be provided.