Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Reexamination Certificate
2002-06-11
2003-07-22
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
C174S112000, C040S316000, C116S200000, C191S02200C
Reexamination Certificate
active
06596942
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wire harness such as, for example, for vehicle or automotive applications, that includes several unitary wire harnesses each containing a plurality of electrical cables. In particular, the invention relates to colored electrical cables.
2. Description of Background Information
A typical automobile is usually wired with hundreds of electrical cables. These electrical cables are assembled into several unitary wire harnesses, each unitary wire harness being assigned to a specific car section.
As shown in
FIG. 1A
, such unitary wire harnesses include, for instance, an engine compartment harness W/H-
1
, an engine harness W/H-
2
wired above the engine, a cowl harness W/H-
3
wired in the dash panel (cowl panel), an instrument panel harness W/H-
4
, a floor harness W/H-
5
wired from the front side to the rear side along the car floor, a door harness W/H-
6
wired in the doors on both sides, and a roof harness (not shown in the figure) wired along the car roof.
Among them, a large-scale wire harness, such as an engine harness, an engine compartment harness, a cowl harness and an instrument panel harness, contains at least thirty to fifty, and typically one hundred to three hundred electrical cables.
In a unitary wire harness such as shown in
FIG. 1B
, a number of electrical cables W are bundled and taped, so as to form a trunk section and branch sections. Each end portion of the electrical cables is terminated with a connector K. Further, certain determined positions of the trunk and branch sections are mounted with fitting members such as clips to be hooked to a car body, protectors for safeguarding the harness, or corrugated tubes.
As shown in
FIG. 2
, an end portion of each electrical cable W is fitted with an electrical terminal T, and the latter is inserted into a corresponding terminal enclosure a, b or c, etc., formed in a connector K. During this operation, workers are susceptible of making connection errors. To avoid such mistakes, the electrical cables are differentiated by colors.
As shown in
FIG. 3
, a first electrical cable
5
is composed of a core wire aggregate
1
and an insulator coating
2
. The latter has a plain (or solid) base color
3
a
(i.e. dominant or background color) in suitable colors, such as, red, blue, yellow, green, black or the like. A second electrical cable
6
has a plain base color
3
a
same as for the first electrical cable
5
, and is further provided with, for example, two stripes
3
b
. The plain base colors
3
a
and colors of the stripes are thereby differentiated, so that workers can differentiate those electrical cables. The base color
3
a
may be provided in the entire insulator coating
2
, or only on its external surface. By contrast, the stripes
3
b
are colored only on the external surface of the insulator coating.
The first and second electrical cables W may be respectively provided or spotted with identification codes
3
c
in suitable colors such as silver, red or black, etc., at given intervals along their length. The shape of the identification codes
3
c
is a function of properties such as, for example, the material and thickness of the insulator coating, the diameter of the core wire aggregate, the size of the electrical cable, etc. However, these designation identification codes
3
c
are not included in the different cable color markings in the sense of the invention, beside the plain base colors
3
a
and the striped cable colors
3
b.
As can be understood from above, many types of cable color may be used in an automobile. Further, a work bench for mounting unitary wire harnesses is usually provided with an arrangement table such as shown e.g. in FIG.
5
A. The color of an electrical cable W is made to correspond to a particular terminal enclosure among a plurality of terminal receiving means of connector K, to which the cables are to be inserted, so that erroneous connections can be avoided. In other words, the cable color sets are differentiated as a function of the destination of the electrical cables W (e.g. electrical cables W destined for a circuit). A circuit can thus be connected by inserting a given colored cable into the corresponding terminal enclosure. When the correspondence is erroneous, a desired circuit cannot be constructed.
One difficulty of harness arrangement resides in the fact that connectors in a vehicle or an automobile are initially joined to existing electric parts, for example, electronic control units and junction boxes, and the connections of unitary wire harnesses must be adapted to these situations. Further, a unitary wire harness may be connected between several connectors by crossing with other partially-connected wire harnesses, so that the electrical cables of one harness intertwine with those of other harnesses, and it is often difficult to attribute these cables to their terminal receiving elements in a consistent manner.
The electrical cables W to be engaged into terminal receiving means, in the form of enclosures or receptacles a, b and c etc. of a connector K, are identified by the corresponding cable colors. As the number of terminal receiving elements multiplies, the types of color to be used must also be multiplied so as to avoid misconnections.
Recent years have witnessed the multiplication of the number of terminal receiving elements formed in each connector K. Nowadays, its number sometimes reaches forty. Accordingly, many types of cable color are now being used. For instance, thirteen base colors are combined with different stripe colors, yielding, for example, forty six kinds of cable color.
However, when the cable colors are multiplied, the electrical cables produced become much more expensive. In addition, when the cables' size is small, the width of the stripe colors and that of the base colors become undistinguishable. As a result, it becomes difficult not only to identify the base colors, but also to distinguish the stripe colors from the base colors. This makes the workers' task particularly burdensome.
SUMMARY OF THE INVENTION
The present invention thus has for object to reduce the types of cable color required without risk of connection errors, to reduce the manufacturing costs of cables, and to alleviate fatigue on workers due to color differentiation efforts. To this end, there is provided a method for determining a critical number of colors for the electrical cables constituting a wire harness such as, for example, a vehicle or an automotive wire harness. The wire harness includes a plurality of unitary wire harnesses to be engaged with a given number of connectors. Each of the unitary wire harnesses contains a plurality of electrical cables which respectively have a different color marking and include an electrical terminal attached to at least one end thereof, and each of the connectors includes a plurality of terminal receiving elements respectively configured to receive a corresponding electrical terminal, so that each of the unitary wire harnesses can be engaged with a given number of connectors. The above method further comprises:
selecting a critical unitary wire harness among the plurality of unitary wire harnesses;
determining the critical number of different color markings to be contained in the critical unitary wire harness on the basis of the empirical formula:
R=A/B+C/B
(I)
in which R is the critical number of different color markings; A is the total number of electrical cables contained in the critical unitary wire harness; B is the total number of connectors to be engaged with the critical unitary wire harness; and C is the total number of terminal receiving elements contained in all of the connectors to be engaged with the critical unitary wire harness; and
setting the total number of different cable color markings necessary for each of the plurality of unitary wire harnesses to be equal to or less than the critical number of different color markings.
Selecting a critical unitary wire harness may include choosi
Ito Takeharu
Uchiyama Kenichi
Greenblum & Berstein P.L.C.
Nino Adolfo
Reichard Dean A.
Sumitomo Wiring Systems Ltd.
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