COVERED ELECTRIC WIRE CONTINUITY CHECK METHOD AND ELECTRIC WIRE HOLDER THEREFOR

Technical Field

The present invention is related to continuity check of an electric wire for a vehicle interior illumination unit and more particularly to a continuity check method for a covered electric wire making up a wiring harness which is provided in an electric wire holder which has no conducting component and an electric wire holder therefor.

Background Art

It is already generally known to make electric contact with electric wires accommodated in a connector which has no conducting component in an interior thereof by use of a press-fit member (refer to PTL1). A connector described in PTL1 includes a press-fitting cover, and electric wires and contacts are press fitted together by this press-fitting cover for making electric connection between the electric wires and the contacts.

Citation List

[Patent Literature]

[PTL1] JP-A-2006-147273

Summary of Invention

Technical Problem

It is therefore one advantageous aspect of the present invention to provide a continuity check method in which a continuity check can be performed on an electric wire accommodated in an electric wire holder having no conducting component, thereby obviating the necessity of performing a continuity check on the electric wire in the electric wire holder after the electric wire holder is connected to electric equipment.

Solution to Problem

According to one advantage of the invention, there is provided a continuity check method for a covered electric wire, comprising:

removing an insulation cover of a portion near one end portion of a covered electric wire to be checked over a predetermined length;

laying a core conductor wire portion exposed by removing the insulation cover in an electric wire holder having an opening;

inserting a continuity checking terminal into the opening so as to be contacted with the exposed core conductor wire portion, and

applying electric current between the continuity checking terminal and the other end of the covered electric wire to check the continuity of the covered electric wire which is mounted in the electric wire holder.

According to another advantage of the invention, there is provided an electric wire holder for checking a covered electric wire for continuity, comprising:

an inner holder; and

a cover configured to cover the inner holder,

wherein the inner holder is formed with a groove in which a covered electric wire is laid, and

wherein the cover is formed with an opening into which a continuity checking terminal is inserted, at a location where the covered electric wire is situated in a state where the cover covers the inner holder.

In the electric wire holder, core conductor wire holding portions configured to hold a core conductor wire of the covered electric wire are provided along a lengthwise direction of the groove on the inner holder with a predetermined space defined therebetween.

Advantageous Effects of Invention

According to the invention, the insulation cover of the covered electric wire is partially removed over the predetermined length so as to expose the core conductor wire, and the exposed portion is laid at a top portion on the inner holder covered with the cover having the opening. Therefore, it is possible to inspect the electric wires laid at the top portion for alignment thereof from colors of the electric wires. Additionally, even in the event that the cover is placed over the inner holder, a continuity check can be performed only by inserting the continuity inspecting terminal into the opening in the cover. Therefore, the covered electric wire provided in the electric wire holder having no conducting component can easily be inspected for continuity.

Further, since the continuity check is performed easily when a wiring harness is completed, a similar continuity check on a completed product can be omitted.

Additionally, when this electric wire holder is finally installed in a vehicle interior illumination unit, the load is reduced which is applied to the electric wire holder since there exists no insulation cover at the portion of the electric wire where a press-fit cutting blade on the side of the vehicle interior illumination unit bites into the core conductor wire in the electric wire holder. According to the invention, by providing the core conductor wire holding portions on the inner holder, the portion of the electric wire where the insulation cover is removed can be aligned with the core conductor holding portions, thereby making it possible to accurately position the relevant portion of the electric wire on the inner holder in an easy fashion.

Brief Description of Drawings

Figs. 1A to 1C show perspective views depicting electric wires and an electric wire holder which are used in a continuity check method according to the invention. Fig. 1A is a perspective view of the electric wires before removal of insulation covers of intermediate portions thereof, Fig. 1 B is a perspective view of the electric wires after the removal of the insulation covers of the intermediate portions thereof, and Fig. 1C is a perspective view of the electric wire holder before constituent parts thereof are fitted together.

Figs. 2A to 2C show perspective views depicting a method for mounting electric wires in a connector which is assembled to a vehicle interior illumination unit shown in Figs. 9A and 9B by use of an electric wire laying jig conceived separately by the applicant of this patent application. Fig. 2A is a perspective view showing a state before the connector is assembled to the electric wire laying jig, Fig. 2B is a perspective view showing a state in which the connector is temporarily fixed on the electric wire laying jig, and Fig. 2C is a perspective view showing a state before the covered electric wires are mounted in the electric wire holder.

Figs. 3A to 3C show perspective views depicting an electric wire mounting method for mounting the electric wires in the electric wire holder. Fig. 3A is a perspective view showing a state immediately before the electric wires are assembled into the electric wire holder, Fig. 3B is a perspective view showing a state in which the electric wires are temporarily fixed in the holder, and Fig. 3C is a perspective view showing a state in which the electric wires are completely mounted in the electric wire holder.

Figs. 4A and 4B show enlarged views of a head portion of the electric wire holder shown in Fig. 3B where the electric wires are laid. Fig. 4A is a perspective view of the head portion and Fig. 4B is a sectional view of the head portion taken along the line B-B and seen in a direction indicated by arrows B shown in Fig. 4A. Figs. 4C and 4D show enlarged views of a head portion of a modified example of an electric wire holder. Fig. 4C is a perspective view of the head portion and Fig. 4D is a sectional view of the head portion taken along the line C-C and seen in a direction indicated by arrows C in Fig. 4C.

Figs. 5A to 5D show preparatory work for the continuity check method according to the invention. Figs. 5A and 5B show a state before insertion of continuity inspecting terminals and Figs. 5C and 5D show a state after the continuity inspecting terminals are inserted. Specifically, Fig. 5A is a perspective view showing an overall configuration of the preparatory work including the electric wire laying jig, and Fig. 5B is a vertical sectional view of a portion lying near the head portion of the electric wire holder shown in Fig. 5A. Fig. 5C is a perspective view showing the overall configuration of the preparatory work including the electric wire laying jig, and Fig. 5D is a vertical sectional view of the portion lying near the head portion of the electric wire holder in Fig 5C.

Fig. 6 is an overall view. o.La.. continuity .check system which realizes the continuity check method of the invention.

Fig. 7 is a perspective view of a rear side of a vehicle interior illumination unit to which the related art is applied.

Fig. 8 is an exploded perspective view showing a vehicle interior illumination unit to which the invention is applied.

Figs. 9A and 9B show drawings depicting a state in which an electric wire holder having no conducting component incorporated therein is mounted in the vehicle interior illumination unit shown in Fig. 8. Fig. 9A is a perspective view of a rear side of the vehicle interior illumination unit showing a state before the electric wire holder according to the invention is fitted in a first connector, and Fig. 9B is a perspective view of the rear side of the vehicle interior illumination unit showing a state in which the electric wire holder is completely fitted in the first connector.

Fig. 10A is a plan view of the vehicle interior illumination unit as seen from the rear side of the vehicle interior illumination unit in Fig. 9B, and Fig. 10B is a sectional view of the vehicle interior illumination unit taken along the line D-D in Fig. 10A.

Fig. 11 C is an enlarged view of a portion of Fig. 10B which is surrounded by an oval depicting the first connector into which the electric wire holder is completely fitted. Figs. 11A and 11 B are vertical sectional views depicting intermediate steps taken before reaching Fig. 11 C depicting the first connector into which the electric wire holder is completely fitted, Fig. 11A depicting a state before fitment, Fig. 11 B depicting a state during fitment.

Figs. 12A to 12C show drawings depicting a state in which a busbar and a metallic fixture of the vehicle interior illumination unit are mounted in the vehicle interior illumination unit. Fig. 12A is a perspective view of the rear side of the vehicle interior illumination unit depicting a state before the busbar and the metallic fixture are mounted, Fig. 12B is a perspective view of the rear side of the vehicle interior illumination unit depicting a state in which the busbar and the metallic fixture are completely mounted, and Fig. 12C is an enlarged view of a portion denoted by reference character A in Fig. 12B.

Figs. 13A to 13C show drawings depicting a state in which a switch of the vehicle interior illumination unit is mounted in the vehicle interior illumination unit. Fig. 13A is a perspective view of the rear side of the vehicle interior illumination unit showing a state before the switch is mounted, Fig. 13B is a perspective view of the rear side of the vehicle interior illumination unit as seen from a right end, showing a state in which the switch is are completely mounted, and Fig. 13C is a perspective view showing the rear side of the vehicle interior illumination unit as seen from a left end, showing the state in which the switch is completely mounted.

Figs. 14A and 14B show drawings depicting a state in which a switch knob of the vehicle interior illumination unit is mounted in the vehicle interior illumination unit. Fig. 4A is a front perspective view showing a state before the switch knob is mounted, and Fig. 14B is a front perspective view showing a state in which the switch knob is completely mounted.

Figs. 15A and 15B show drawings depicting a state in which a bulb (an electric lamp) of the vehicle interior illumination unit is mounted in the vehicle interior illumination unit. Fig. 15A is a front perspective view showing a state before the bulb is mounted, and Fig. 15B is a front perspective view showing a state in which the bulb is completely mounted.

Figs. 16A and 16B show drawings depicting a state in which a lens of the vehicle interior illumination unit is mounted in the vehicle interior illumination unit. Fig. 6A is a front perspective view showing a state before the lens is mounted, and Fig. 16B is a front perspective view showing a state in which the lens is completely mounted. Description of Embodiments

The press-fitting connector of PTL1 is such that the press-fitting cover which holds plural electric wires is pressed directly against a housing so that the electric wires are press fitted in press-fitting grooves formed in the contacts. This press-fitting cover is effective when the number of electric wires to be press fitted for electric connection is small. However, when the number of electric wires is large, a large operation force becomes necessary, leading to a problem that the press-fitting work cannot be completed properly unless an exclusive press-fitting jig is used. Consequently, there is caused a problem that it is difficult to fabricate a wiring harness in a site where no exclusive press-fitting jig is prepared.

With a view to solving this problem, a connector according to a related art is proposed by the applicant of this patent application. According to the related art, the connector can be obtained which requires neither an exclusive press-fitting jig nor an end treatment involving many labor hours in production of a wiring harness so as to reduce the production cost of a wiring harness and which is free from quality reduction due to fouling of terminals made when a wiring harness is laid so as to improve the reliability of the wiring harness produced.

Fig. 7 is a perspective view of a housing including a holder receiving portion according to the related art. Fig. 7 shows a state in which an electric wire holder including a holder receiving portion is inserted vertically and a mounting shaft portion of the electric wire holder is in engagement with a holder bearing portion of the holder receiving portion. In Fig. 7, a vehicle interior illumination unit 100 includes a housing 400, and a first connector 430 is provided on a rear side 400R of the housing 400. A busbar 500 is fixed to this first connector 430, and many press-fit cutting blades 510 are disposed in the first connector 430. On the other hand, a second connector 600 in which electric wires W2 are held by a holder 610 and cover 620 is rotated about a rotating shaft 600S so as to be placed on the first connector 430 for contact therewith. Then, by fitting the second connector 600 on the first connector 430, such many press-fit cutting blades 510 individually bite into the corresponding electric wires W2 whereby electric connection is made therebetween.

According to the vehicle interior illumination unit 100 according to the related art, the second connector 600 only has to be rotated about the rotating shaft 600S to be placed on the first connector 430 for contact therewith/and therefore, it is possible to obviate the necessity of the exclusive press-fitting jig and the end treatment involving many labor hours, thereby making it possible to reduce the production cost of a wiring harness. Additionally, it is also possible to prevent the occurrence of quality reduction which would otherwise be caused due to fouling of terminals made when a wiring harness is laid, thereby making it possible to improve the reliability of the wiring harness produced.

However, no core conductor wire exposed portion is provided on the electric wires in the electric wire holder, and insulation covers of the electric wires are cut or displaced by the press-fit cutting blades for electric connection when the electric wire holder is connected to electric equipment. Therefore, there is caused a problem that a continuity check cannot be performed on the electric wires which make up the wiring harness before the wiring harness is connected to the electric equipment.

In the continuity check method according to the invention, a continuity check can be performed on an electric wire accommodated in an electric wire holder having no conducting component, thereby obviating the necessity of performing a continuity check on the electric wire in the electric wire holder after the electric wire holder is connected to electric equipment.

Firstly, a vehicle interior illumination unit will briefly be described by reference to the drawings in which vehicle interior illumination unit an electric wire holder with electric wires is mounted to which a continuity check method of the invention is applied.

Fig. 8 is an exploded perspective view of a vehicle interior illumination unit to which the invention is applied. In Fig. 8, the vehicle interior illumination unit 10 is mounted in a bulkhead panel (a ceiling panel) which defines a passenger compartment of a vehicle and briefly includes a substantially rectangular lens 20, a longitudinally elongated switch knob 30, a substantially rectangular housing 40 and a busbar 50.

A bulb accommodation compartment 41 is formed in the housing 40 on a front side 40F thereof, and a bulb 41 B, which is a light source, is assembled in a central portion of the bulb accommodation compartment 41. A switch accommodation compartment 42 is provided in a side portion of the housing 40, and the switch knob 30 is assembled into the switch accommodation compartment 42 from the front side 40F so as to slide therein.

Additionally, a first connector 43 is provided at one end portion of the housing 40 so as to project endways of the housing 40. An electric wire holder 60 (Fig. 9A) in which electric wires W which make up a wiring harness are fixed in place is fitted in the first connector 43. A metallic clip 44 (Fig. 8) is fixed to the other or opposite end portion of the housing 40 to the end portion where the first connector 43 is provided for mounting the vehicle interior illumination unit 10 in the bulkhead panel which defines the passenger compartment of the vehicle therewith. A switch 42R (Fig. 9), which is linked with the switch knob 30 for operation, is assembled into the switch accommodation compartment 42 from a rear side of the housing 40. The busbar 50 (Fig. 8), which is a circuitry for electrically connecting the switch 42R and the bulb 41 B, is fixedly assembled to the rear side of the housing 40. Plural press-fit cutting blades 51 (Fig. 8) are disposed at one end of the busbar 50 so as to be parallel to each other in a vertical direction. The press-fit cutting blades 51 are then fixedly mounted within the first connector 43.

Next, the electric connection by the press-fit cutting blades 51 will be described by reference to Figs. 9A to 11C.

Figs. 9A to 11 C are drawings depicting a method for mounting an electric holder having no conducting component incorporated therein in the vehicle interior illumination unit shown in Fig. 8. Fig. 9A is a perspective view of a rear side of the vehicle interior illumination unit showing a state before the electric wire holder 60 (which will be described later) according to the invention is fitted in the first connector, and Fig. 9B is a perspective view of the rear side of the vehicle interior illumination unit showing a state in which the electric wire holder 60 is completely fitted in the first connector. Fig. 10A is a plan view of the vehicle interior illumination unit as seen from the rear side thereof showing the state in which the fitting of the electric wire holder into the first connector is completed, and Fig. 10B is a sectional view of the vehicle interior illumination unit taken along the line D-D in Fig. 10A. Fig. 11C is an enlarged view of a portion of Fig. 0B which is surrounded by an oval E depicting the first connector into which the electric wire holder is completely fitted. Figs. 11 A and 11 B are vertical sectional views depicting intermediate steps taken before reaching Fig. 11 C depicting the first connector into which the electric wire holder is completely fitted. Fig. 11 A depicts a state before fitment, and Fig. 11 B depicts a state during fitment. In Figs. 9A and 9B, the electric wire holder 60 to which the electric wires W are fixed fits in the first connector 43. The switch 42R and the busbar 50 are fixed to the rear side of the housing 40, and the press-fit cutting blades 51 (Fig. 8) of the busbar 50 are fixed to the first connector 43. Even in case the electric wire holder 60 has no conducting component incorporated therein, when the electric wire 60 is inserted into the first connector 43 to be fitted together with the first connector 43 as shown in Fig. 9B, as shown in Figs. 10A and 10B, the press-fit cutting blades 51 enter an interior of the electric wire holder 60 from openings therein and bite directly into core conductor wires C of the covered electric wires W, resulting in a state in which the electric wires W and the press-fit cutting blades 51 are electrically connected to each other. In the invention, openings are provided in the electric wire holder 60 into which the press-fit cutting blades 51 are inserted, and this will be described later. Insulation covers of the covered electric wires W are removed in advance, and this will be described later.

Fig. 11 A is a vertical sectional view depicting a state before the electric wire holder 60 according to the invention is fitted in the first connector 43. The electric wire holder 60 is made up of an inner holder 61 and a cover 62 which is placed over the inner holder 61. In Fig. 11 A, electric wires (core conductor wires) W1 , W2, W3 are laid at a head portion (a left-hand side in the figure) of the inner holder 61 , and the cover 62 covers the whole of the inner holder 61 in that state.

On the other hand, the busbar 50 is fixed to the housing 40 side, and the press-fit cutting blades 51 are formed at a distal end of the busbar 50.

Fig. 11 B is a vertical sectionaLview depicting-an- intermediate step of fitting. The press-fit cutting blades 51 enter from openings 62K formed in the cover 62 of the electric wire holder 60, and the electric wires (core conductor wires) W2 which are laid at the head portion of the inner holder 61 are introduced into slot portions of the press-fit cutting blades 51. A lock beak 61 B of the inner holder 61 has not yet been brought into engagement with a locking portion 43B of the first connector 43.

Fig. 11 C is a vertical sectional view depicting a state in which the fitting of the electric wire holder 60 into the first connector 43 is completed. In this state, the lock beak 61 B is in engagement with the locking portion 43B, and the press-fit cutting blades 51 bite into the electric wires (core conductor wires) W2, whereby the press fitting of the press-fit cutting blades on to the electric wires is completed. As this occurs, the insulation covers of the covered electric wires W2 have already been removed according to the invention (this will be described later), and therefore, the load is reduced which is applied to the electric wire holder when it fits in the first connector 43 as a result of the press-fit cutting blades 51 entering the interior of the electric wire holder 60.

Figs. 12Ato 12C show drawings depicting a state in which the busbar and the metallic fixture of the vehicle interior illumination unit are mounted in the vehicle interior illumination unit. Fig. 12A is a perspective view of a rear side of the vehicle interior illumination unit depicting a state before the busbar and the metallic fixture are mounted, Fig. 12B is a perspective view of the rear side of the vehicle interior illumination unit depicting a state in which the busbar and the metallic fixture are completely mounted, and Fig. 12C is an enlarged view of a portion denoted by reference character A in Fig. 12B.

In Figs. 12A to 12C, the metallic clip 44 is brought into engagement with an engagement groove 44R (Fig. 12A) which is provided on an end face of the housing 40 which is opposite to an end face where the first connector 43 (Figs. 9A to 11A) is provided so as to be fixed in place therein, and the busbar 50 is fixedly mounted on the rear side of the housing 40 so as to extend thereover entirely. The busbar 50 is temporarily fixed to the rear side of the housing 40 by plural projections 40T (Fig. 12C) which are formed on the rear side and thereafter is fixed thereto by use of a fusion bonding method in which distal ends of the projections 40T are fused.

Figs. 13A to 13C show drawings depicting a state in which the switch of the vehicle interior illumination unit is mounted in the vehicle interior illumination unit. Fig. 13A is a perspective view of the rear side of the vehicle interior illumination unit depicting a state before the switch is mounted, Fig. 13B is a perspective view of the rear side of the vehicle interior illumination unit as seen from a right end, depicting a state in which the switch is completely mounted, and Fig. 13C is a perspective view of the rear side of the vehicle interior illumination unit as seen from a left end, depicting the state in which the switch is completely mounted. The switch 42R is mounted in the switch accommodation compartment 42 provided in the housing 40 from the rear side of the housing 40 so as to be fixed in place therein.

Figs. 14A and 14B show drawings depicting a state in which the switch knob of the vehicle interior illumination unit is mounted in the vehicle interior illumination unit. Fig. 14A is a front perspective view showing a state in which the switch knob is mounted, and Fig. 14B is a front perspective view showing a state in which the switch knob is completely mounted. The switch knob 30 is mounted slidably within the switch accommodation compartment 42 from the front side 40F of the housing 40 so as not only to be linked with the switch 42R for operation but also to cover the switch accommodation compartment 42 so that an interior of the compartment is concealed thereby.

Figs. 15A and 15B show drawings depicting a state in which the bulb of the vehicle interior illumination unit is mounted in the vehicle interior illumination unit. Fig. 15A is a front perspective view showing a state before the bulb is mounted, and Fig. 15B is a front perspective view showing a state in which the bulb is completely mounted. The bulb 41 B is mounted substantially in the central portion of the bulb accommodation compartment 41 from the front side 40F of the housing 40 for electric connection with the busbar 50.

Figs. 16A and 16B show drawings depicting a state in which the lens of the vehicle interior illumination unit is mounted in the vehicle interior illumination unit. Fig. 16A is a front perspective view showing a state before the lens is mounted, and Fig. 16B is a front perspective view showing a state in which the lens is completely mounted. The lens 20 is mounted on the housing 40 from the front side 40F thereof so as to cover and conceal the housing 40 as a result of plural engagement pieces 20S which are formed at both sides of the lens 20 in positions lying at substantially longitudinal ends of the lens 20 being brought into engagement with engagement projections 40S which are formed on both lateral side faces of the housing 40 in positions lying at substantially longitudinal ends of the housing 40. As this occurs, an opening portion 21 formed in the lens 20 is brought into contact with lateral side faces and end faces of the switch knob 30.

Thus, the description is completed of the overall configuration of the vehicle interior illumination unit to which the invention is applied and the main constituent parts thereof.

Figs. 1A to 1C show perspective views depicting the electric wire holder (second connector) 60 (Figs. 9A and 9B) which is fitted in the first connector 43 (Figs. 9A and 9B) of the vehicle interior illumination unit 10 (Figs. 9A and 9B) and the covered electric wires W which are laid in the electric wire holder 60. Fig. 1A is a perspective view of the electric wires before removal of insulation covers of intermediate portions thereof, Fig. 1B is a perspective view of the electric wires after the removal of the insulation covers of the intermediate portions thereof, and Fig. 1C is a perspective view of the electric wire holder in which core conductive wires exposed as a result of the removal of the insulation covers are laid.

Electric wires shown in Fig. 1A are covered electric wires W1 , W2, W3 which make up a wiring harness, and core conductor wires C1 , C2, C3 pass through centers of insulation covers of the covered electric wires W1 , W2, W3, respectively. Different electric wire colors are applied individually to the covered electric wires W1 , W2, W3 so that they can be differentiated from each other.

In executing a continuity check method according to the invention, the insulation covers of the three covered electric wires W1 , W2, W3 are partially removed over a predetermined length at locations near end portions thereof, so that the core conductor wires C1 , C2, C3 are exposed as shown in Fig. 1 B. The predetermined length means a length corresponding to a length of the opening 62K which extends over the top portion of the inner holder 61, which will be described later.

The electric wires W1 , W2, W3 in which the core conductor wires C1 , C2, C3 are exposed in the way described above are laid at the top portion of the inner holder 61 of the electric wire holder 60 shown in Fig. 1C so that the exposed core conductor wires C1 , C2, C3 are laid individually in three grooves 63 provided on the top portion. The electric wires W1 , W2, W3 are then bent downwards at both ends of the exposed core conductor wires C1 , C2, C3 so as to extend downwards along grooves formed along both lateral sides of the inner holder 61.

Here, the configuration of the electric wire holder 60 shown in Fig. 1C will be described.

The electric wire holder 60 includes the inner holder 61 and the cover 62 which is connected with an end portion of the inner holder 61 via a flexible hinge 61 H. The grooves 63 along which the covered electric wires W are laid are formed on the inner holder 61 so as to extend along the top portion and both the lateral side portions of the inner holder 61. Locks 6 R are formed on the inner holder 6 , and fitting locks 62R are formed on the cover 62 which are brought into engagement with the locks 6 R when the cover 62 is placed on the inner holder 61. Referring to Fig. 1C, a cover inserting portion 6 K is formed at a lower edge portion of the inner holder 61. The inner holder 61 and the cover 62 are integrated together via the flexible hinge 61 H which is formed integrally with the cover 62 by a distal end of the flexible hinge 61 H being inserted into the cover inserting portion 61 K. Additionally, the lock beak 61 B is present on an external side of the inner holder 61. This lock beak 61 B is brought into engagement with the locking portion 43B (refer to Figs. 11 B and 11C) of the first connector 43 which is a mating connector in which the electric wire holder 60 fits.

The cover 62 is built into a substantially U-shaped structure in vertical section, and therefore, a cover opening preventive rib 62S is formed on the cover 62 which connects portions of leg portions of the rib 62S which lie near distal ends of the leg portions so as to prevent the opening of the leg portions when the cover 62 is placed over the inner holder 61. This is because the leg portions of the cover 62 tend to be opened easily due to the structure of the cover 62.

In Fig. 1C, although a lower end of the cover 62 is difficult to be visualized, openings 62K are formed in the lower end of the cover 62 at respective inspecting locations for the covered electric_wires-W-1-,-W2, W3 which are laid at the top portion of the inner holder 61 so that the core conductor wires C1 , C2, C3 are not concealed but stay visible and accessible when the cover 62 is placed over the inner holder 61. The shape of the opening 62K is not limited, and hence, any shape may be adopted, provided that the shape allows continuity inspecting terminals M1 , M2, M3 (Figs. 5A and 5B) to be inserted thereinto.

Figs. 2A to 2C show drawings depicting a method used for mounting the electric wires on to the connector which is assembled to the vehicle interior illumination unit shown in Figs. 9A and 9B by utilizing an electric wire laying jig which is conceived separately by the applicant of this patent application. Fig. 2A is a perspective view showing a state before the connector is assembled to the electric wire laying jig, Fig. 2B is a perspective view showing a state in which the connector is temporarily fixed on the electric wire laying jig, and Fig. 2C is a perspective view showing a state before the electric wires are mounted on the electric wire holder.

In Fig. 2A, an electric wire holder support 71 is provided on the electric wire laying jig 70 in a position lying on a center line and near one edge portion of the electric wire laying jig 70. The electric wire holder support 71 includes an inner holder support 71 A on which the inner holder 61 is placed and a cover support 71 B on which the cover 62 is placed. Thus, the inner holder 61 and the cover 62 of the electric wire holder 60 are placed on the inner holder support 71 A and the cover support 7 B, respectively. As this occurs, since a holder positioning projection 71T is provided on the inner holder support 71 A so as to project upwards therefrom, by placing the inner holder 61 on this positioning projection 71T, the inner holder 61 can be positioned accurately.

When the cover 62 placed on the cover support 71B is dislocated from the cover support 71 B and is then rotated o_nJ _ _. theJnner holder 6 via the flexible hinge 61 H, the cover 62 is placed smoothly over the inner holder 61 from thereabove so that the cover 62 and the inner holder 61 are fitted together, whereby the electric wire holder 60 is completed.

Positioning pins 72 of two types, that is, third connector positioning pins 72A and electric wire positioning pins 72B are provided on the electric wire laying jig 70 so as to be erected therefrom.

The third connector positioning pins 72A are positioning pins for positioning a third connector 80. These positioning pins 72A are provided side by side at another edge portion of the electric wire laying jig 70 so as to be spaced apart with a gap corresponding to the width of the electric wire defined therebetween.

The electric wire positioning pins 72B are positioning pins for positioning the electric wires, and these electric wire positioning pins 72B are disposed individually near four corners of the electric wire laying jig 70. A number of the electric wire positioning pins 72B is four in Figs. 2A to 2C.

The plural electric wires W which are aligned vertically extend in a horizontal direction from the third connector which is fixed by the third connector positioning pins 72A, and the electric wires W are caused to turn around lateral sides of the individual electric wire positioning pins 72B so as to change the direction in which they extend through 90 degrees while kept aligned vertically, thereby making it possible to lay the electric wires so that they follow the side edge portions of the electric wire laying jig 70 while being bent accordingly at the four corners thereof. In addition, a number of the electric wires W is three in Fig. 2C.

Next, a method will be described for laying the electric wires in the electric wire holder by utilizing the electric wire laying jig described above.

In a first step of the electric wire laying or assembling method, the inner holder 61 of the electric wire holder 60 is carried to be positioned directly above the holder positioning projection 71T (refer to Fig. 2A). As a second step, the inner holder 61 is lowered in a direction indicated by a thick white arrow outlined with a black solid line in Fig. 2A and is then placed on the holder positioning projection 71T so that the electric wire holder 60 is temporarily fixed on to the support 71 (refer to Fig. 2B).

As a third step, the third connector 80 to which the plural electric wires W are attached is carried above the electric wire laying jig 70. As this occurs, ends of the three electric wires W which lie to face the third connector 80 are positioned directly above the pair of third connector positioning pins 72A, 72A, and the remaining portions of the three electric wires W are positioned so as to extend across the electric wire laying jig 70 thereabove in a straight line while being aligned vertically (Fig. 2C).

As a fourth step, the whole of the third connector 80 with the electric wires W is lowered as they are in a direction indicated by a thick white arrow outlined with a black solid line in Fig. 2C. Then, firstly, the third connector 80 is brought into abutment with external sides (which are sides lying opposite to the electric wire laying jig 70) of the third connector positioning pins 72A, 72A (Fig. 2C), and root portions of the covered electric wires W which lie at the third connector 80 are caused to be held between the third connector 3 positioning pins 72A, 72A (Fig. 3A).

As a fifth step, the three vertically aligned electric wires W which extend from the third connector 80 are caused to pass around the lateral side of the electric wire positioning pin 72B which lies closest to the third connector positioning pins 72A to change the direction in which they extend. Then, the electric wires W are caused to pass further around the lateral side of the next electric wire positioning pin 72B so as to be brought to near the inner holdeLs.upport 71A.

As a sixth step, the three vertically aligned electric wires W which arrive at the inner holder support 71A are changed in orientation to be inserted individually into the plural grooves 63 which are formed on the top portion of the inner holder 61 which is being temporarily fixed on to the inner holder support 7 A so that the electric wires are aligned in a horizontal direction.

As a seventh step, the three electric wires W which have passed over the top portion of the inner holder 61 are aligned vertically again and are caused to pass around the lateral side of the following electric wire positioning pin 72B to change the direction in which they extend and are further caused to pass around the lateral side of the following electric wire positioning pin 72B to change the direction in which they extend, whereby the electric wires W are led out from an opposite side of the electric wire laying jig 70 to the side where the third connector positioning pins 72A are provided (Fig. 3A).

As a eighth step, when the other or free end portions of the three vertically aligned electric wires W which extend from the third connector 80 are pulled strongly in a direction indicated by an arrow F (in an opposite direction to the third connector 80) shown in Fig. 3B, loosening in the electric wires W is mitigated by the electric wire positioning pins 72B. Additionally, the electric wires W which are loosely laid in the plural grooves 63 on the inner holder 61 are then firmly fixed in the corresponding grooves 63, whereby the core conductor wires C1 , C2, C3 (refer to Fig. 1B) of the insulation covered electric wires W1 , W2, W3 (refer to Fig. 1 B) are individually accommodated in the plural grooves on the top portion of the inner holder (Fig. 3B).

In this state, as a ninth step, by folding or rotating the cover 62 at the hinge portion so as to be placed on the inner holder 61 , the electric wires W are held by the inner holder 61 and the cover 62 therebetween so that the electric wires W are fixed in place within the electric wire holder 60. In this state, the core conductor wires C1 , C2, C3 (refer to Fig. 1 B) of the insulation covered electric wires W1, W2, W3 (refer to Fig. 1B) are situated below the openings 62K in the cover 62. Thus, by completing the steps described above, the electric wires W are mounted completely in the electric wire holder 60 (refer to Fig. 3C).

In this way, by use of the electric wire laying jig 70, the loosening in the electric wires W can be eliminated, and the electric wires W can be mounted accurately in the electric wire holder.

Figs. 4A and 4B show enlarged views of the head portion of the electric wire holder in which the electric wires shown in Fig. 3B are laid. Fig. 4A is a perspective view of the head portion, and Fig. 4B is a sectional view of the head portion taken along the line B-B and seen in a direction indicated by arrows B in Fig. 4A.

The electric wires W1 , W2, W3 are laid individually in the three grooves 63 which are provided in parallel on the top portion of the inner holder 61. It is understood that respective insulation covers H2 (refer to Fig. 4B) of portions of the electric wires W1, W2, W3 which are situated at the head portion are removed so that the core conductor wires C1 , C2, C3 (refer to Fig. 4B) are exposed.

The width of the groove 63 is formed slightly narrower than the outside diameter of the covered electric wires W1 , W2, W3. Therefore, the strain applied to the covered electric wires W1 , W2, W3 are relieved by bendability inherent in the covered electric wires W1 , W2, W3 and being held by the inner holder 61.

Figs. 4C and 4D show enlarged views of a head portion of an inner holder 61' which is a modified example (Embodiment 2) made to the inner holder 61 shown in Fig. 4(A). Fig. 4C is a perspective view of the head portion, and Fig. 4D is a sectional view taken along the line C-C and seen in a direction indicated by arrows C in Fig. 4C.

The inner holder 61' differs from the inner holder 61 in that two core conductor wire holding portions 61 F are provided for each of the three grooves 63 on the head portion so as to be spaced a predetermined distance apart from each other. The core conductor wire holding portion 61 F may be formed into any shape, provided that the electric wire held thereby can be made difficult to move back and forth and from side to side. However, in Embodiment 2, the core conductor wire holding portion 61 F is formed into a member having a U-shaped section and is formed so that an opening portion in the U-shaped section is oriented upwards. The predetermined distance or space between the two core conductor wire holding portions 61 F means that a distance or space between outer sides of the two core conductor wire holding portions 61 F shown in Fig. 4B equals the length of a portion of the core conductor wire C2 which is exposed as a result of the insulation cover H2 of the relevant portion of the covered electric wire W2 being removed.

Consequently, by forcing the portions of the electric wires W1 , W2, W3 which correspond to the exposed core conductor wires C1 , C2, C3 into the opening portions of the two core conductor wire holding portions 61 F having the U-shaped section which are provided for each of the three grooves 63 provided in parallel on the inner holder 61 ' so as to be fixed in place therein, the electric wires W1 , W2, W3 are made difficult to move back and forth and from side to side.

When the covered electric wires W1 to W3 are laid on the head portion of the inner holder 61 and the inner holder 61' (refer to Fig. 3B, Figs. 4Ato 4D), the cover 62 which is fixed on to the cover support 71 B (refer to Fig. 3B) is removed from the cover support 71 B and is then turned towards the inner holder support 71 A so as to be placed over the inner holder 61, so that both- the cover 62 and the inner holder 61 are fitted together. Thus, the electric wire holder 60 is completed as shown in Fig. 3C. As this occurs, the openings 62K (refer to Fig. 1C) which are formed in the bottom portion of the cover 62 are situated at the head portion of the electric wire holder 60 in Fig. 3C.

Figs. 5A to 5D show preparatory work for the continuity check method according to the invention. Figs. 5A and 5B show a state before insertion of the continuity inspecting terminals. Figs. 5C and 5D show a state after the continuity inspecting terminals are inserted. Specifically, Fig. 5A is a perspective view showing an overall configuration of the preparatory work including the electric wire laying jig, and Fig. 5B is a vertical sectional view of a portion lying near the head portion of the electric wire holder shown in Fig. 5A. Fig. 5C is a perspective view showing the overall configuration of the preparatory work including the electric wire laying jig, and Fig. 5D is a vertical sectional view of the portion lying near the head portion of the electric wire holder.

In Figs. 5A and 5B, the continuity inspecting terminals M1 , M2, M3 are moved to above the electric wire holder 60, and the continuity inspecting terminals M1 , M2, M3 are then lowered from thereabove. Then, as shown in Fig. 5C, the continuity inspecting terminals M1 , M2, M3 individually enter the three openings 62K in the cover 62 of the electric holder 60. In an interior of the electric wire holder 60, for example, the continuity inspecting terminal M2 is brought into contact with an upper portion of the core conductor wire C2 via the opening 62K as shown in Fig. 5D, whereby the continuity inspecting terminal M2 and the core conductor wire C2 are electrically connected to each other.

The other continuity inspecting terminals M1 , M3 are brought into contact with the corresponding core conduGtor-wires-G-1— G3 in- a similar fashion, whereby the continuity inspecting terminals M1 , M3 and the corresponding core conductor wires C1 , C3 are electrically connected to each other. In this way, by inserting the continuity inspecting terminals M1 , M2, 3 into the corresponding openings 62K in the electric wire holder 60, the continuity inspecting terminals M1 , M2, M3 are brought into electric contact with the corresponding core conductor wires C1 , C2, C3 of the covered electric wires W1 , W2, W3. Thus, the continuity check system shown in Fig. 6 can be realized.

Fig. 6 shows the continuity check system which realizes the continuity check method of the invention.

In Fig. 6, a terminal holder 2 to which the continuity inspecting terminals M1, M2, M3 are attached and one end 4T1 of the power supply 4 are connected to each other via meters 5 by electric wires 6.

On the other hand, the covered electric wires W1 , W2, W3 to be inspected which are laid by the electric wire laying jig 70 shown in Figs. 2A to 3C are mounted in the electric wire holder 60, and the other ends of the covered electric wires W1, W2, W3 are connected to the third connector 80 (refer to Fig. 3C). Since conducting terminals are incorporated in the third connector 80, the conducting terminals are connected to the other end 4T2 of the power supply 4 via the three electric wires 6. A rear end treatment is applied to rear end portions of the covered electric wires W1, W2, W3 which have passed through the electric wire holder 60 in which the rear end portions are folded back so as to bound together with the covered electric wires W1 , W2, W3 by an adhesive tape or the like.

Then, when the continuity inspecting terminals M1 , M2, M3 are inserted into the corresponding openings 62K in the cover 62 of the electric wire holder 60, the continuity inspecting terminals M1 , M2, M3 come into contact with the core conductor wires C1 , C2, C3 of the corresponding covered electric wires W1, W2, W3 as is described by reference to Fig. 5, whereby a closed circuitry is completed in which the continuity inspecting terminals M1 , M2, M3 each include the power supply 4.

Then, in case there exists no disconnection somewhere along the length of the covered electric wires W1 , W2, W3 to be inspected, an electric current flows to the meters (ammeters) 5, as a result of which pointers of the meters 5 swing largely, whereby it is understood that there is no "disconnection."

On the contrary, in case there exists a disconnection somewhere along the length of any of the covered electric wires W1 , W2, W3 to be inspected, no electric current flows to the corresponding meter 5 provided along the length of the electric wire, as a result of which the pointer of the meter 5 does not swing, whereby it is understood that there exists a disconnection somewhere along the length of the covered electric wire to which the meter 5 is connected.

In this way, it is determined that the covered electric wires pass the check by verifying the fact that the respective pointers of the meters 5 swing.

Although the ammeters are used as the meters 5 in this embodiment, voltmeters may be used in place of the ammeters.

Additionally, light emitting diodes may be used in place of the meters 5. In this case, it is determined that the covered electric wires pass the check when it is confirmed that the light emitting diodes emit light.

The reason that the three openings 62K in the cover 62 of the electric wire holder 60 are formed so as to be offset from each other in the direction of the length of the covered electric wires is that the fears of mutual contact of the continuity inspecting terminals M1 , M2, M3 are avoided.

According to the invention, only part of the insulation covers of the covered electric wires are removed over the predetermined length so as to expose the core conductor wires, and the exposed portions of the covered electric wires are laid at the top portion of the holder with the cover having the openings. Therefore, the electric wires can be inspected for whether or not they are aligned properly from the colors of the electric wires laid at the top portion. Additionally, even in the event that the cover is placed over the inner holder, only by inserting the continuity inspecting terminals into the openings in the cover, the continuity check can be performed. Therefore, the continuity check can easily be performed on the covered electric wires which are provided in the electric wire holder having no conducting component.

Further, the continuity check can easily be performed on the electric wires making up the wiring harness at the point in time when the wiring harness is completed, and therefore, a similar check to be performed on a completed product can be omitted.

In addition, when the electric wire holder is finally mounted in the vehicle interior illumination unit, the press-fit cutting blades on the vehicle interior illumination unit side bite into the core conductor wires in the electric wire holder. However, since the insulation covers of the portions of the covered electric wires into which the press-fit cutting blades bite have already been removed, the load is reduced under which the electric wire holder is fitted into the connector of the vehicle interior illumination unit.

Additionally, by utilizing the electric wire holder including the core conductor wire holding portions, the portions of the covered electric wires where the insulation covers are removed can be aligned with the core conductor wire holding portions, thereby making it possible to accurately position the exposed core conductor wires at the top portion of the electric wire holder in a easy fashion.

The above-mentioned embodiment is merely a typical example of the present invention, and the present invention is not limited to the embodiment. That is, the present invention can be variously modified and implemented without departing from the essential features of the present invention.

The present application is based on Japanese Patent Application No. 2011-094359 filed on April 20, 2011 , the contents of which are incorporated herein by way of reference.

Industrial Applicability

In accordance with a continuity check method of the invention, a continuity check can be performed on an electric wire accommodated in an electric wire holder having no conducting component, thereby obviating the necessity of performing a continuity check on the electric wire in the electric wire holder after the electric wire holder is connected to electric equipment.

Reference Signs List

10: VEHICLE INTERIOR ILLUMINATION UNIT

20: LENS

30: SWITCH KNOB

40: HOUSING

41 : BULB ACCOMMODATION COMPARTMENT

41 B: BULB

42: SWITCH ACCOMMODATION COMPARTMENT

42R: SWITCH

43: FIRST CONNECTOR

43B: LOCKING PORTION

44: METALLIC CLIP 50: BUSBAR

51 : PRESS-FIT CUTTING BLADE

60: ELECTRIC WIRE HOLDER

61 , 61 ': INNER HOLDER

6 B: LOCK BEAK

61 F: CORE CONDUCTOR WIRE HOLDING PORTION

61 H: FLEXIBLE HINGE

61 K: COVER INSERTING PORTION

62: COVER

62K: OPENING

62R: FITTING LOCK

62S: COVER OPENING PREVENTIVE RIB

63: GROOVE

70: ELECTRIC WIRE LAYING JIG

71A: INNER HOLDER SUPPORT

71 B: COVER SUPPORT

80: THIRD CONNECTOR

4: POWER SUPPLY

4T1 : ONE END

4T2: THE OTHER END

5: METER (AMMETER)

6: ELECTRIC WIRE

C1 , C2, C3: CORE CONDUCTOR WIRE

Ml , M2, M3: CONTINUITY INSPECTING PRESS-FIT CUTTING BLADE W1 , W2, W3: COVERED ELECTRIC WIRE