Cabling system and method for connecting electronic printed circuit boards

A cabling system and method for connecting, to a plurality of electronic printed circuit boards, a common electrical cable, a grounding cable, and respective electrical board wires, or power supply cables. The system comprises a bundle of electrical cables, and a plurality of multipolar, insulation-piercing connectors placed in succession along said bundle of cables. Each of the connectors is suitable to receive the common electrical cable, the board cable to be connected to the respective electronic board, and the board cables that must be connected to the successive connectors, and is suitable to transmit to a successive insulation-piercing connector, the common electrical cable and the board cables that must be connected to the successive connectors.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and all the benefits of Italian Patent Application No. 102015000035996, filed on Jul. 20, 2015, the entire content of which is expressly incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention covers a cabling system, in particular to deliver independent electrical power supplies to a plurality of electronic printed circuit boards, for example the boards of a motor vehicle lamp.

2. Description of the Related Art

Many electrical or electronic devices include a plurality of printed circuit boards spaced, and sometimes arranged parallel with each other, to each of which must be brought a respective power supply, the ground and possibly other signals, for example, for diagnostics.

For example, in the same motor vehicle lamp there are printed circuit boards for lights having different functions, for example, position, turn and stop lights, etc. To the light is fixed an electrical connector (called in the jargon “car connector”) to which is connected a bundle of power supply, ground and diagnostic cables. The different electronic boards of the light must be connected through respective cables to this connector, so as to be independently powered, connected to ground and possibly controlled by means of diagnostic signals.

In some cases, such as for the motor vehicle lamp, it is of primary importance to perform the electrical cabling of the boards so as to reduce as much as possible the space occupied by the cables, the length of the cables themselves, and optimise the path of the cables to reduce the risk of breakage, overheating, etc.

Moreover, there is a need to perform the cabling of the electronic boards in an automatic or semi-automatic manner.

To attempt to meet these needs, use is often made of insulation-piercing multipolar connectors with a “splitter” function, i.e., in which the electrical cable enters the connector, such as a grounding cable or a power cable, and several output electrical cables exit from the connector, all connected to the input cable and directed towards the boards to be simultaneously connected to earth or powered.

FIG. 1illustrates a system for cabling the electronic printed circuit boards of a motor vehicle lamp according to the prior art. In the example shown, the motor vehicle lamp comprises two electronic boards for a rear light (Tail Up and Tail Lower), an electronic board for the turn signal (Turn) and an electronic board for the brake light (Stop). To each of these boards is fixed a respective insulation-piercing connector1to4. To the light is fixed an input electrical connector5from which extend a GROUND cable, a power supply cable of the rear light TAIL, a power cable of the direction indicator TURN, a power cable of the brake light STOP, and a diagnostic cable DIAG to check the correct operation of the turn signal.

As you can see, the GROUND cable enters the connector4of the brake light, exits from this connector4and enters the connector3of the Tail Low light. From this connector3, two GROUND cables exit, one directed to the connector2of the turn signal and one directed to the connector1of the rear light Tail Up.

The power supply cable of the rear light TAIL enters the connector3of the Tail Low light, exits from this connector3and enters the connector1of the Tail Up light.

The power supply cable of the TURN signal enters directly into the connector2of the Turn signal.

The power supply cable of the STOP light enters directly into the connector4of the Stop light.

The diagnostic cable DIAG enters directly into the connector2of the Turn signal.

As can be seen fromFIG. 1, although, compared to a traditional connection in which each board is connected to the input electrical connector to the lamp (car connector) in a manner completely independent from the others, the use of splitter connectors allowed achieving a certain rationalisation, at least as regards the ground cable, the cabling system still presents cables that extend between the input electrical connector and boards in a disorderly manner and form branches and curves that can give rise to malfunctions or damage.

SUMMARY OF THE INVENTION

The purpose of this invention is to propose a cabling system capable of eliminating the drawbacks complained about above with reference to the prior art.

This purpose is achieved with a cabling system for connecting, to a plurality of electronic printed circuit boards, a common electrical cable, for example a grounding cable, and respective electrical board wires, for example power supply cables for independently powering at least some of said electronic boards, comprising a bundle of electrical cables comprising the common electrical cable and a plurality of board cables, at least some of the board cables being intended to be connected independently to respective electronic boards. A plurality of multipolar, insulation-piercing connectors are placed in succession along said bundle of cables. Each of said connectors is suitable to be connected to a respective electronic board for electrically connecting, to the electronic board, the common cable and at least board cable, each insulation-piercing connector, with the exception of a connector terminal that terminates the bundle of cables, being suitable to receive the common electrical cable, the board cable to be connected to the respective electronic board, and the board cables that must be connected to the successive connectors, and being suitable to transmit to a successive insulation-piercing connector, or the terminal connector, the common electrical cable and the board cables that must be connected to the successive connectors.

This purpose is also achieved with a cabling method for connecting, to a plurality of electronic printed circuit boards, a common electrical cable, for example a grounding cable, and respective electrical board wires, for example power supply cables for independently powering at least some of said electronic boards, comprising the steps of preparing a bundle of electrical cables comprising the common electrical cable and a plurality of board cables; preparing a plurality of multipolar insulation-piercing connectors, each being suitable to be connected to a respective electronic board for electrically connecting to said electronic board the common cable and at least one board cable, each connector being provided with a plurality of cable seats, at least some of said cable seats being engageable by an insulation-piercing electrical contact; inserting, in a respective cable seat of each insulation-piercing connector, the common electrical cable, the board cable to be connected to the respective electronic board, and the board cables that must be connected to the successive connectors; extracting from the respective cable seats of each insulation-piercing cable connector, with the exception of a terminal connector that terminates the bundle, the common electrical cable and the cables that must be connected to the successive connectors; making the electrical contact between the electric cables and the respective boards.

At last, this purpose is achieved with a motor vehicle lamp comprising a plurality of electronic printed circuit boards suitable to drive respective light sources to realise lights of the lamp, an input electrical connector at the input of the lamp, from which extends a bundle of cables comprising a grounding cable to be connected to all the electronic boards and a plurality of power supply cables, at least some of which to be independently connected to respective electronic boards, and a cabling system of the bundle of cables to the electronic boards as defined herein before.

DETAILED DESCRIPTION OF THE INVENTION

With reference toFIG. 2, the reference number10indicates, in its entirety, a cabling system for connecting, to a plurality of electronic printed circuit boards12-18, a common electrical cable22, for example a grounding cable, and electrical board cables23-29, for example power supply cables, at least some of such board cables having to be connected to a single, respective, electronic board. In other words, at least some of the boards receive their own board signal independently from each other.

The cabling system10comprises a bundle of cables21, for example coming from an input electrical connector20. The bundle of cables21comprises the common electrical cable22and a plurality of board cables23-29.

The cabling system10also comprises a plurality of insulation-piercing multipolar connectors30-36placed in succession along the bundle of cables. Each of said multipolar connectors30-36is suitable to be connected to a respective electronic board12-18for connecting to said electronic board the common electrical cable22and a respective board cable.

Insulation-piercing multipolar connector means a multi-way connector, i.e., provided with multiple cable seats40electrically insulated from each other and suitable to receive respective electrical cables. Furthermore, at least some of these cable seats are engageable by an insulation-piercing electrical contact42suitable to pierce, i.e., cut, the insulating sheath that surrounds the conductive wires of the electrical cable, so as to allow a passage of electric current between the conductive wires and the electrical contact. The latter is also electrically connected to a respective terminal of the electronic board to which the connector is fixed.

At least some of the cable seats40are pass-through. Pass-through cable seat means that the electrical cord that enters the cable seat passes through the connector and exits from the cable seat to be inserted in the cable seat of a successive connector.

Preferably, the entrance and exit of a pass-through cable seat40are aligned with each other.

A pass-through cable seat40may be provided with an insulation-piercing electrical contact42(FIGS. 4, 4a) or may be without such an electrical contact (FIG. 4b). In this second case, the connector functions merely as a retention and guide element for the electrical cable that is not engaged by the electrical contact.

In one embodiment, all the cable seats have insulation-piercing electrical contacts but not all the electrical contacts are electrically connected to the respective board.

In one embodiment, for reasons of production efficiency, all the cable seats40are equal and all are pass-through. The electrical cables that enter in a connector but do not continue towards the successive connectors are simply cut at the exit of the cable seat.

In one embodiment, the insulation-piercing electrical contacts42are movable between a retracted position of disengagement from the cable seat, so as to allow the insertion of the cable in the cable seat, and an advanced position, in which they perform the piercing or cutting of the sheath of the cable.

For example, the insulation-piercing connectors comprise two connector parts44,46, one movable (44) with respect to the other (46). One part supports the insulation-piercing contacts42and the other part forms the cable seats40.

Each insulation-piercing connector, with the exception of a terminal connector, is thus suitable to receive from a preceding insulation-piercing connector, or from the input connector if it is the first of the plurality of multipolar connectors, the common cable22, the board cable23, . . . ,29for the respective electronic board, and the board cables23, . . . ,29intended to be connected to the successive connectors.

Each multipolar connector, with the exception of the terminal connector36, is also suitable to transmit to a successive multipolar connector or to the terminal connector36or the common cable22and the board cables that must be connected to the successive connectors.

Therefore, the cabling system10comprises at least one terminal connector36, placed at the distal end of the bundle of cable21, and a header connector30, which receives all the cables of the bundle of cables21.

The header connector30is provided with a number of electrically-insulated cable seats in which are inserted the common cable22and all the board cables23-29, for example coming from the input connector20.

The cable seat of the common cable22is pass-through and is engaged by an insulation-piercing contact suitable to electrically connect the common cable22to the electronic board12connected to the header connector30. Another cable seat of the header connector30receives a board cable23and is engaged by an insulation-piercing contact suitable to electrically connect this board cable23to the electronic board12connected to the header connector30.

The remaining cable seats24-29for board cables are pass-through and the respective electrical cables are not engaged by insulation-piercing electrical contacts.

Between the terminal connector36and the header connector30is positioned at least one insulation-piercing intermediate connector31, . . . ,35. This intermediate connector is provided with a number of electrically-insulated cable seats in which are inserted the common cable22and the board cables coming from the header connector30or from a preceding intermediate connector. The cable seat for the common cable22is pass-through and is engaged by an insulation-piercing contact suitable to electrically connect the common cable22to the respective electronic board; another cable receives a board cable24and is engaged by an insulation-piercing contact suitable to electrically connect the board cable to the respective electronic board; the remaining cable seats for the board cables are pass-through and the respective electrical cables are not engaged by insulation-piercing electrical contacts.

In one embodiment, the cables of the cable bundle are arranged alongside each other so as to form a flat bundle, also called a “strip”. Correspondingly, the multipolar connectors have a predominantly linear extension, with the cable seats alongside each other and lying in a seat plane. In this way, the bundles of cables maintain the shape of a strip.

In one embodiment that allows facilitating the cabling of the bundle of cables to the multipolar connectors in an automatic or semi-automatic manner, all the multipolar connectors have the cable seat for the common cable positioned at a same end of the connector.

Furthermore, in one embodiment the cable seat of the board cable of the board connected to the insulation-piercing connector is positioned at the opposite end of the connector with respect to the cable seat for the common cable.

Therefore, as is evident from the cabling diagram ofFIG. 2, the number of cables exiting from the multipolar connectors decreases proceeding from the opposite end with respect to the common cable.

Preferably, therefore, one can use connectors with a decreasing number of cable seats, arranging them from the largest header (facing the input connector) to the smallest (the terminal connector).

In one embodiment, the insulation-piercing multipolar connectors are Lumberg series 35, 2.5 pitch, “pass-through” connectors. An example of such connectors is shown inFIGS. 4-4b. InFIG. 4, note the pass-through cable seat40with the insulation-piercing electrical contact in the inactive retracted position; inFIG. 4a, note the electrical contact in the advanced position of piercing the insulating sheath of an electrical cable22, . . . ,29;FIG. 4bshows a pass-through cable seat without insulation-piercing contact, with the sole function of guiding the cable that passes through the connector.

In one embodiment, the cabling system can include intermediate bifurcations, as shown for example inFIG. 3. Here, from an intermediate connector31′, three cables22,23,24depart directed towards a first connector32and two other cables25,26depart towards a second successive connector32′. From the first successive connector32, two electrical cables22,23depart and terminate in the terminal connector36.

FIG. 5shows the cabling system according to the invention for the electronic boards of a motor vehicle lamp. The cabling system comprises an input connector110, an electronic board for the brake light (Stop)120, a first electronic board for a first group of light sources of a rear light (Tail Lower)130, an electronic board for the turn signal (Turn)140, and a second electronic board to a second group of rear light sources (Tail Up)150. To each of these boards is fixed a respective insulation-piercing connector300to310.

From the input electrical connector110extend a ground cable220that must be connected to all the electronic boards, a power supply cable for the rear light230, which must be connected to both the first and the second board of the rear light, a power supply cable240of the electronic board140of the turn signal, a power supply cable250of the electronic board of the brake light120, and a diagnostic cable260to be connected to the electronic board of the turn signal140to check the correct functioning of the turn signal.

As it can be seen fromFIGS. 2 and 5, in all the connectors the seat for the ground cable is positioned at the left end of these connectors, and these are aligned along a reference line X tangent to that left end of all the connectors.

The five electrical cables220-260exiting from the input connector110enter the first insulation-piercing connector300, which is therefore equipped with five ways or cable seats.

The power supply cable250of the electronic board of the brake light120ends in the first connector300. Therefore, from this first connector extend four electrical cables220,240,250,260that enter the second connector310of the first board for the rear light130. Since, in this case, also the second board150for the rear light must be powered with the same power supply cable of the first board230, from the second connector310exit four electrical cables220,230,240,260. Of course, of the four power cables that pass through the second connector310, only the ground cable220and the power supply cable of the boards of the rear light230are cut by respective insulation-piercing electrical contacts. The other two cables are simply retained and guided by the second connector.

The four electrical cables enter the third connector320of the electronic board of the turn signal. In this third connector, the power supply cable of the respective board240and the diagnostic cable260end after being cut by the respective insulation-piercing electrical contacts.

Then, from the third connector, there exit only the first cables (from the left)220,230of the initial bundle of cables: the ground cable230and the power supply cable230of the second board of the rear light. These two cables end in the fourth (terminal) connector330.

Comparing the cabling system ofFIG. 1andFIG. 5, note how the second has no branch connectors, is much more orderly and has significantly shorter cables.

The cabling system according to the invention can be advantageously realised with an automatic or semi-automatic machine that implements the following method of cabling electronic printed circuit boards.

The cabling method according to the invention comprises the following steps:

preparing a bundle of electrical cables comprising the common electrical cable and a plurality of board cables;

preparing a plurality of multipolar insulation-piercing connectors, each being suitable to be connected to a respective electronic board for electrically connecting to said electronic board the common cable and at least one board cable, each connector being provided with a plurality of cable seats, at least some of said cable seats being engageable by an insulation-piercing electrical contact;

inserting, in a respective cable seat of each insulation-piercing connector, the common electrical cable, the board cable to be connected to the respective electronic board, and the board cables that must be connected to the successive connectors;

extracting from the respective cable seats of each insulation-piercing cable connector, with the exception of a terminal connector that terminates the bundle, the common electrical cable and the cables that must be connected to the successive connectors;

making the electrical contact between the electric cables and the respective boards.

Preferably, the connectors used have cable seats that are adjacent to one another and lie in a seat plane so as to form flat bundles of cables between the connectors.

Preferably, the cable seat for the common cable is positioned at one end of each insulation-piercing connector, and the connectors are positioned so as to be aligned with respect to a reference line tangent to said connector end.

This invention also covers a motor vehicle lamp400comprising a plurality of electronic printed circuit boards120-150suitable to drive respective light sources to realise lights of the lamp, an input electrical connector110provided at the entrance of the lamp and from which extends a bundle of cables comprising a grounding cable220to be connected to all the electronic boards and a plurality of power supply and/or other electrical signal cables, at least some of which to be independently connected to respective electronic boards, and a cabling system10of the bundle of cables to the electronic boards as described above.

To the embodiments of the cabling system and method according to the invention, a man skilled in the art, to satisfy contingent requirements, may make modifications, adaptations and replacements of members with others functionally equivalent, without departing from the scope of the following claims. Each of the characteristics described as belonging to a possible form of embodiment can be achieved independently from the other embodiments described.