Electrical Harnesses and Connecting Devices Therefor

This invention relates to electrical harnesses and to improved methods of manufacturing electrical harnesses. The invention is herein described as an embodiment intended for use in a motor vehicle but other uses of the invention will be apparent from the description which follows.

It is common practice to manufacture an electrical harness by lacing the wires for the harness around appropriately located pegs on a harness board, applying bundle ties to the wires, removing the laced wires from the harness board, stripping insulation from the ends of the wires, applying terminals to the wire ends and finally, inserting the terminals into connector housings. Alternatively, some harnesses are manufactured by manufacturing the individual leads having terminals on their ends in a lead making machine, storing the leads in bins, selecting one or more leads from each bin for the harness, and assemblying the harness from the individual leads. Both methods are relatively time consuming and are subject to errors on the part of the technician which must later be corrected. Furthermore, these harnesses making methods do not discourage the use of an unnecessarily high number of different types of connectors and terminals in the harness. It is not uncommon for a harness of the type used in an automobile or an electrical appliance to have several different styles or types of terminals and connectors on the harness when, in fact, one or two standard types could be used. This lack of standardization probably is a result of the fact that the apparatus on which the harness is used was designed by different groups of designers and each group of designers selected the terminals for the components of the apparatus for which the group has responsibility. Finally, the assembly process in which harnesses are assembled to the apparatus is somewhat unsatisfactory in that after the cables of the harness have been secured in place in the apparatus, the different types of connectors on the harness must be mated or coupled with complementary connectors extending from the components on the apparatus and the lack of standardization tends to complicate this process and lengthen the time required for carrying it out.

In accordance with the principles of the instant invention, the wires of the harness are simply bundled together, or they are provided as a flat cable and at every location at which an electrical connection is to be made to a wire in the harness, that wire is electrically exposed (e.g. the insulation is stripped from the wire). A standard connecting device is then clamped onto the wire, this connecting device having an insulating body member and a contact arm which engages the electrically exposed wire. The body also has an opening therein for an electrical plug which, when inserted, electrically contacts or engages the contact arm. The plug in turn is secured to a wire which extends from an electrical switch or load.

It is accordingly an object of the invention to provide an improved method of manufacturing electrical harnesses. A further object is to provide an improved connecting device intended for use on electrical harnesses. A further object is to provide a connecting device which can be used to make all, or virtually all, of the connections required in the harness to electrical loads or electrical switches. A further object is to provide a connecting device which can be readily inspected after application to a harness so that a determination can be made of the efficiency of the connection.

These and other objects of the invention are achieved in preferred embodiments thereof which are briefly described in the foregoing application, which are described in detail below and which are shown in the accompanying drawing in which:

FIG. 1 is a semi-diagrammatic plan view of an electrical harness in accordance with the invention.

FIG. 2 is a perspective view of a connecting device used in the harness of FIG. 1.

FIG. 3 is a cross-sectional view of a connecting device applied to the conductors in a harness.

FIG. 4 is a perspective view of a ferrule used in the practice of the invention.

FIG. 5 is a perspective view of a ferrule crimped onto an intermediate portion of a wire.

FIG. 6 is a view taken along the lines 6--6 of FIG. 3.

FIG. 7 is a fragmentary plan view illustrating the manner in which two connecting devices can be applied to a single conductor in a cable for different electrical circuits.

FIG. 8 is a cross-sectional view of a connecting device having an integral fastener.

Referring first to FIG. 1, the disclosed form of harness comprises an electrical multi-conductor cable 2 made up of a plurality of insulated wires 4. It will be understood that the wires may be of the form of a ribbon cable which is a cable containing a plurality of wires in side-by-side co-planar relationship with the insulating sheath of each wire being integral with the insulating sheaths of adjacent wires. If the cable is composed of separate wires, as an alternative, the wires would be positioned in side-by-side co-planar relationship in the connecting device 30 described below.

A plurality of loads are selectively connected to the conductors 4 and these loads may comprise a horn 6, a windshield wiper 10, high and low beam headlights 12 and additional lights 8. The ends 14, 16 of the cable may extend to additional loads and the cable may have a number of conductors greater than that shown in the drawing. The individual loads are grounded as shown at 20 and are connected to the connecting devices 30 by leads 18.

Power is supplied to these circuits by a battery 22 from which a power cable 24 extends. The power cable is connected to a group of connecting devices 30 through individual switches 26 and electrical leads 18 which extend from the switches to the connecting devices 30.

The connecting devices 30 may be identical to each other and each connecting device comprises a generally prismatic body 32 (FIG. 2) of glass-filled nylon or other firm moldable insulating material. Body 32 has a cable receiving face 36, a back 38, sides 40, 42 and ends 44, 46. A cable receiving recess 34 extends into the face 36 and intersects the sides 40 , 42 of the body 32. The inner surface 48 of this recess serves as a cable supporting surface, and is further recessed as shown at 50 for reasons which will be explained below. The opposed sides 52, 54 of the recess are spaced apart by a distance which is substantially equal to the sum of the diameters of the wires 4, or by the width of the cable, so that the conductors can be placed in the recess in side-by-side relationship as shown in FIG. 3.

A slot 56 extends inwardly from the end 46 of the body and to the cable receiving recess 34 as shown at 58. A slot 60 extends into the end 44 and similarly intersects the side 52 of the recess 34. These slots accomodate the ends of the contact member or contact arm 62 in the form of a rod or heavy wire which has a reversely bent free end 64 and which extends across the cable receiving recess. The lefthand end of the contact member 62 is also reversely bent as shown at 68 and has an end portion 70 which extends rightwardly in FIG. 3 beyond a roll pin 72. The roll pin is located in an opening in the body 32 and extends from the side 40 to the side 42. The end portion 70 of the contact arm is formed in a manner such that contact arm is loosely pivoted in the slot 56 but cannot fall away from the body 32. The reverse bend 64 on the righthand end portion of the contact arm 62 has a curvature which conforms to a curved surface 66 in the slot 60.

A plug receiving opening 74 extends through the body from the side 40 to the side 42 adjacent to the roll pin 72 but relatively closer to the end 46 than is the roll pin. This opening is adapted to receive a plug member 78 which is crimped onto one of the wires 18. The plug member has a tapered leading end and a circumferentially extending recess 80 adjacent to its end. The opening 74 for the plug member is located such that when the plug member is inserted into the opening, the contact arm will be flexed and the reversely bend end 64 pulled tightly against the surface 66 of the slot 60.

When it is desired to form an electrical connection to a predetermined conductor 4 in the cable, a portion of the conductor is electrically exposed by stripping insulation from the conductor and crimping a ferrule 80 onto the metallic core of the wire. The U-shaped ferrule is crimped only in its center portions as shown at 82 so that four separate legs 84 are provided at the ends of the ferrule. The wires of a cable are then positioned in the recess 34 with the legs 84 of the ferrule against the depressed center portion 50 of the recess as shown in FIG. 6. The contact arm is then swung inwardly and snapped over the contoured surface 66 of the slot 60. The electrical connection of the conductor which has been electrically exposed to one of the conductors 18 is then effected by simply inserting the plug 78 into the opening 74 until the reversely bent portion 68 of the contact member 62 snaps into the circumferential recess 80 of the plug. As previously mentioned, the parts are advantageously dimensioned such that the contact member will be flexed and/or tensioned when the plug is inserted so that good contact pressure will be obtained at the point of contact between the surface of the ferrule and the contact arm. It should also be mentioned that during such flexure and/or tensioning of the contact arm, there will be relative movement of the surface of the contact arm over the surface of the ferrule and this relative movement of the two parts will have the effect of scouring the contact surfaces so as to ensure a good electrical connection. It is preferable to form the opening 74 such that the plug can be inserted from either side 40 or 42 of the housing.

If the conductors are in the form of a flat cable having their insulating sheaths integral, one of the conductors can be used for two circuits as shown in FIG. 7 by simply removing a portion of the conductor as shown in 86 and applying ferrules 80 adjacent to the gap which remains after removal of the portion of the conductor. Connecting devices 30 can then be assembled to the cable on each side of the gap and the rightwardly extending portion 4a of the conductor can be used for one circuit while the leftwardly extending portion 4b of the conductor can be used for a different circuit.

Under many circumstances, it is desirable to provide at least one "hot" conductor in the cable in order that isolated lights or other devices can be connected to this conductor. In FIG. 1, one conductor 4c is connected directly to the power distribution conductor 24 rather than being connected through a switch to the power distribution conductor as are the other branch conductors in the harness. If it is desired to provide, for example, a courtesy light 86 adjacent to one of the doors of the vehicle, the energized conductor 4c is tapped by a connecting device 30 and a connection is made as shown at 87 between the connecting device and a switch 88. The conductor extending from the switch is connected to the courtesy light 86 and a suitable ground connection is provided as shown at 90. The switch 88 would be a conventional normally open push button switch which would be held in closed condition by the vehicle door when the door is closed. The provision of an energized conductor 4c thus permits the installation of lights of this type at any desired location adjacent to the cable.

FIG. 8 shows a modified form of connecting device 30' which is generally similar to the previously described embodiment but which also has an integral cover 92 hinged at 94 to the body member 32'. After the connecting device has been installed on the cable, the cover 92 is closed for purposes of protection and, if desired, sealing. Connecting device 30' also has an integral fastener 96 and a positioning boss 98 extending from its body portion 32' so that it can be attached to panel 100 if desired.

FIG. 1 shows the wires 4 of the cable as being in side-by-side co-planar relationship in all portions of the cable including those portions which extend between the connecting devices 30. If the wires 4 are separate wires rather than the conductors in a ribbon cable, the wires may be bunched together in those portions of the harness to which connecting devices are not applied, for example, the portion of the harness which extends from the windshield wiper 10 to the hazard lights 8 in FIG. 1. When the connecting device 30 for the windshield wiper or the hazard lights is applied to the cable, it is merely necessary to flaten the bunched wires and position them in the connecting device 30 as shown in FIG. 3. It should be noted in this respect that the wire to which a contact is being established by a particular connecting device 30 need not be located at any particular position in the cable; in other words, the wire for the ferrule thereon in FIG. 3 could be positioned anywhere between the sidewalls 52, 54 and contact would be established upon assembling the connecting device to the cable.

While the disclosed embodiment shows only a single type of connecting device having one contact arm member 62, it might be feasible under some circumstances to provide connecting devices having several arm members 62 pivotally mounted thereon in side-by-side spaced apart relationship. If a multi-contact connecting device of this type is used, the opening 74 for the plug member 78 would be relocated and the end 68 of the contact member changed so that it would contact the plug 78 upon insertion thereof.

The term "electrically exposed" is used herein to describe the conductor to which a connection is made and the conductor is exposed by stripping the insulation from the wire and crimping the ferrule 80 onto the wire. It will be apparent that other methods might be used to electrically expose the wire to which a connection is to be made. For example, a U-shaped ferrule having suitable insulating piercing means extending from its web might be employed. Upon application of such a ferrule to the wire without crimping, the insulation of the wire will be penetrated and contact established with the conducting core. The contact member 62 would contact the ferrule as described above.

A salient advantage of the invention is that only one type of connecting device 30 is required for the many electrical connections of the loads and the switches to the conductors in the cable. From a manufacturing method standpoint, the invention is advantageous in that the harness can be produced by simply applying ferrules 80 to the conductors at the appropriate locations for the electrical loads and the electrical switches. At the time of assembly of the harness to the vehicle, a connecting devices can be snapped onto the cable at each location where a connection is required and the associated lead wires 18 can be connected to the conductor by simply inserting the plug members 78 into the openings 74 of the connecting devices.