ELECTRIC CONTROL MEANS IN VEHICLES

Abstract: A connecting device (18) is adapted to interconnect lighting points on a traction vehicle (2) and corresponding lighting points of a trailer. A distinctive feature is that the vehicle (2) has an additional cable trunk (14, 14') and an additional trailer contact (20), the connecting device (18) being connected to the additional cable trunk (14, 14'). The connecting device (18) includes a microcomputer and a number of connecting elements, the microcomputer causing, in response to input signals corresponding to the function of the different lighting points of the traction vehicle, the corresponding connecting element to apply a voltage to a given output of the trailer contact (20), which is connected to the corresponding lighting point of the trailer.

Description: ELECTRIC CONTROL MEANS IN VEHICLES The present invention generally relates to an elec¬ tric control means in vehicles and more specifically to a microcomputer-controlled connecting device for intercon¬ necting in particular the electric system of a traction vehicle and that of a trailer. To electrically connect a traction vehicle especially to a foreign trailer taken by ship of train to the border, where it is picked up, is often quite problematic, since there is no international standard for interconnecting electric equipment in vehicles, such as brake lights and direction indicators. This being a well-known problem, several techniques enabling functional connection of the electric systems have been developed in recent years. Usually, this problem is solved by preparing a num¬ ber of intermediate connecting cables which are kept in the traction vehicle. When collecting the trailer in e.g. a harbour, the driver of the traction vehicle tries to pick out the intermediate connecting cable having the right combination for electrically interconnecting the electric systems of the traction vehicle and the trailer. Quite often, the driver is unable to find any con- necting cable that makes all the lighting points of the trailer work properly. In such a case, he has to choose a cable which minimises the malfunction. As a result, only some lighting points of the trailer actually work. To run a heavy vehicle on public roads under such conditions not only is an offence under the road safety regulations, but also constitutes a serious hazard to other road-users. Another solution is suggested in US-A-4,781,393 which relates to an intermediate connecting cable provided with a connecting box. This box has a cable with a connector to be connected to a trailer socket on the traction vehicle. The connector of the trailer is connected to a socket in the connecting box. Each conductor of the intermediate connecting cable is equipped with a contact pin at the end remote from the connector. The connecting box has a plura¬ lity of first female sockets which, via an indicator lamp, are earthed, and a plurality of second female sockets, equal in number to the contacts of the connecting box sockets. Preferably, the connecting box is mounted on the drawbar of the trailer. When using the connecting box described in the above patent specification, the trailer is initially coupled to the traction vehicle, the connector of the intermediate connecting cable is connected to the trailer socket of the traction vehicle, and the connector of the trailer is con¬ nected to the socket of the connecting box. Then, diffe¬ rent lighting points, e.g. the rear lights, of the trac- tion vehicle are lit one by one. The contact pins are con¬ nected to the first female sockets, and a live conductor can be identified by the corresponding indicator lamp being lit. This 'hot' contact pin is then in turn connect¬ ed to each of the second female sockets. Every time, it is verified that the right lighting point of the trailer is lit. Although the device disclosed in US-A-4,781,393 may be said to solve the problems described by way of intro¬ duction, this device is by no means optimal, since it gives rise to new problems. Thus, the connecting box is so positioned that it is highly exposed to dirt and moisture, resulting in oxidation of the contacts, which prevents proper functioning. Another inconvenience is that the driver has to move to the rear of the trailer for every connection cable tested, to check whether the right lighting point is con¬ nected. Also, the comparatively small contact pins may be difficult to handle, e.g. in cold weather when one is wearing gloves or mittens. According to the invention disclosed in DE-OS- 38 19 639, the trailer socket of the traction vehicle is connected, via a connecting device, i.e. a relay, and an associated cable, to the power supply of the traction vehicle, i.e. the generator, and the lighting points of the trailer are lit depending on the position of the con¬ necting device connected to the lighting circuits of the traction vehicle. The invention of DE-OS-38 19 639 aims at preventing voltage drops in the electric lighting circuits of the traction vehicle, since such voltage drops may, in new cars, give rise to a fault indication in e.g. a cruise- control computer monitoring the function of the lighting cirucits. Thus, this prior-art invention does not provide a solution to the problems described by way of introduction, of how to electrically interconnect a traction vehicle and a trailer. The state of the art being thus defined by the teach- ings of US-A-4,781,393, it is an object of the present invention to provide an improved device for interconnect¬ ing the electric system of a traction vehicle and that of a trailer. The device according to the invention should be more reliable and easier to handle than the prior-art devices, and permit being expediently mounted on a traction vehi¬ cle. These and other objects are achieved by a device as set forth in appended claim 1. Further distinctive features and embodiments are recited in the appended subclaims. A preferred embodiment of the invention will be described in more detail below with reference to the accompanying drawings, in which Fig. 1 is a schematic perspective view of a traction vehicle equipped with an additional cable trunk and a connecting device according to the invention; Fig. 2 is a simplified circuit diagram illustrating the connecting device according to the invention and an associated programming unit; and Fig. 3 is a schematic view of a programming unit according to a second embodiment of the invention. Fig. 1 illustrates a traction vehicle 2 with an existing cable trunk 4 running e.g. between a fuse hol¬ der 6 and lighting points 8L, 8R, here representing rear lighting units including e.g. the rear lights, brake lights and direction indicators. A trailer coupling 10 serves to connect a trailer (not shown). The cable 4 branches and is connected to a trailer contact 12 for electric interconnection of the electric systems of the traction vehicle and the trailer. According to the invention, the vehicle 2 is equipped with an additional cable trunk 14, 14', individual conduc¬ tors being connected to suitable contacts in the fuse hol¬ der 6, preferably arranged in the driver's cabin 16. The other ends of the conductors are connected to a connecting device 18, which will be described in more detail below with reference to Figs 2 and 3. Also the connecting device 18 is preferably arranged in the driver's cabin 16. The output of the connecting device 18 is connected to an additional trailer contact 20 provided at the rear of the vehicle. Although the connecting device according to the invention is here described in connection with a traction vehicle towing a trailer, it goes without saying that the invention can also be applied to a traction vehicle with a semitrailer. Figs 2 and 3 schematically illustrate the connecting device 18 (Fig. 3) and its component parts (Fig. 2). The connecting device 18 substantially includes a microcomputer 22 with a number of inputs and outputs. In the embodimet shown in Fig. 2, the microcomputer 22 may be connected to eight outputs UT1-UT8 but, for the sake of clarity, only the circuit configuration of a single output UT1 is illustrated. The microcomputer 22 is adapted to control several relays, of which only the relay 24 connected to the output UT1 is shown in Fig. 2. These relays are activated by a signal S n from the microcomputer 22, and then apply a vol¬ tage U(V) to the respective outputs and, via the associat¬ ed conductor in the cable 14' , to the corresponding light¬ ing point on the trailer. In the released position of the relay 24, the output UT1 is earthed by the movable relay contact 26 of the relay 24. When the relay 24 is operated in response to the signal S n from the microcomputer 22, a driving voltage U(V) is supplied, via a current limiter 28, to the movable relay contact 26 and further to the output UT1. The conductors of the cable 14 which are connected to the fuse holder 6 are connected to inputs of the microcom¬ puter 22 via a signal adapter 30. This adapter is designed to convert the applied voltage into input signals that can be processed by the microcomputer. Finally, in the embodi¬ ment of the invention shown in Figs 2 and 3, a programming unit 32 is connected to the microcomputer 22. In the embo¬ diment of Fig. 2, the programming unit 32 is connected to the microcomputer 22 by a cable 34, whereas the programm- ing unit 32' in Fig. 3 has a suitable transmitter in radio communication with a receiver in the connecting device 18. After having converted the radio signals received, the receiver transmits control signals to the microcomputer 22. As appears from Fig. 3, the state of each output UT1-UT8 is indicated on a display unit, such as a light- emitting-diode display 36, which for every output UT1-UT8 indicates, e.g. by a light-emitting diode 38 of green light, when the corresponding output is activated, i.e. when the output of a certain lighting point of the trailer is occupied, and indicates, e.g. by a light-emitting diode 40 of red light, when the corresponding output is short- circuited. Excepting that the programming unit 32' is equipped with a transmitter and an antenna 42 for wireless trans- mission of control signals to the microcomputer 22, the units 32, 32' illustrated in Figs 2 and 3, respectively, are identical. The programming unit 32, 32' has a program selector 44 for selecting different lighting points on the trailer, such as the right-hand direction indicator, the left-hand direction indicator and the brake lights, or other pro¬ gramming functions, and a command or step-by-step switch 46 for verifying the current setting. It will be appre¬ ciated that the illustrated program selector 44 in the form of a knob may be replaced with several individual switches or pressure contacts. The device according to the invention operates as follows. After the driver of the traction vehicle has mecha- nically coupled a trailer, e.g. in a harbour, the con¬ nector of the trailer is connected to the additional trailer contact 20 of the traction vehicle. The driver activates the lighting points concerned of the traction vehicle, and then takes the programming unit 32 or 32' with him and stations himself behind the trailer. First, the program selector 44 is set in a position *RESET' . When pushing the command button 46, the microcomputer 22 is reset and previous programmings are cancelled. The micro¬ computer 22 returns to an initial position, which means that all control signals S assume a low level, and all outputs UT1-UT8 are earthed, to be activated in turn by a renewed programming. As a result of the resetting, all the light-emitting diodes 38, 40 go out. In this embodiment, the program selector 44 is there- after turned to the position of a first lighting point, e.g. the left-hand direction indicator ('LEFT FLASH'), at the same time as the microcomputer 22 activates the first output UT1, i.e. the signal S n takes a high level, the relay 24 is operated, and the voltage U(V) is applied to the output UTl in the manner described above. If, in this case, the left-hand direction indicator of the trailer is not connected on the conductor connected to the output UTl, another lighting point will instead flash synchronously with the left-hand direction indicator of the traction vehicle. By repeatedly actuating the com¬ mand button 46, the driver is able to sequentially acti- vate the other outputs UT2-UT8 and thus step up to the output providing the desired function. Once the right out¬ put has been found, the program selector 44 is, in this embodiment, turned to the next position for the next lighting point, and the above procedure is repeated. By turning the program selector 44 to the next position and verifying this by means of the command button 46, the sig¬ nal S_ is locked on a low level, and the relay is conse¬ quently locked for the output concerned in released posi¬ tion. Simultaneously, it is noted in the memory of the microcomputer that this output is activated. When search¬ ing for the right output in the following sequence, the microcomputer 22 will disregard this activated output. As mentioned above, a light-emitting diode 38 is lit with a green light when an output is activated. If an out- put is earthed, this is short-circuited when the corre¬ sponding relay is activated. In response to a short-cir¬ cuit current through the current limiter 28, this gene¬ rates a signal S-. which is transmitted to the microcom¬ puter 22. In response to the signal S κ , the signal S_ is caused to take a low level, and a light-emitting diode 40 with a red light is lit for the corresponding output. This output is then rejected and cannot be reactivated in the current programming position. When all the lighting points of the trailer have been allocated a certain output, the program selector 44 is turned to a position 'ACTIVE' . By actuating the command button 46, this position is confirmed, and the microcompu- ter 22 returns from programming position to operating position, in which the microcomputer 22 senses the input signals from the traction vehicle 2 and activates the cor¬ responding outputs in response thereto. Thus, the device described above enables simple and expedient interconnection of the lighting points of a traction vehicle and the corresponding lighting points of a trailer. It takes but little trouble to equip, whenever desir- ed, a traction vehicle with the device according to the invention, and the existent electric system of the vehicle need not be interfered with and can still be used with a domestic trailer having appropriate connectors and cables. Also, the existing electric system can still be used should the new system fail to operate. Since all the sensitive component parts of the device are arranged in the driver's cabin, they are protected against dirt and moisture, which ensures a satisfactory function and a long service life. It goes without saying that other embodiments of the invention and modifications of constructional details are conceivable by those skilled in the art. Some alternative detail constructions have also been briefly touched upon in the foregoing. Naturally, other components with the same technical effect can be used instead of the compo¬ nents mentioned above. For instance, the relays might be replaced with power transistors. All such modifications that fall within the scope of the inventive idea are therefore considered to be encompassed by the appended claims.

Claims: CLAIMS 1. A connecting device (18) with a number of inputs (IN) and a number of outputs (OUT, P) for interconnecting lighting points of a traction vehicle (2) and correspond¬ ing lighting points of a trailer, said traction vehicle (2) having a cable trunk (4) connected to a fuse holder (6), different lighting points (8L, 8R) and a trailer con- tact (12), c h a r a c t e r i s e d in that the trac¬ tion vehicle (2) has an additional cable trunk (14, 14') connected to the fuse holder (6) and an additional trailer contact (20) having a number of outputs (UT1-UT8) and adapted to be connected to the contact means of the trai- ler to transmit a voltage to the different lighting points of the trailer, that the connecting device is connected, via at least some of its inputs and outputs (IN, OUT), to the additional cable trunk (14, 14') between the fuse holder (6) and the additional trailer contact (20), and that the connecting device (18) includes a microcomputer (22) and a number of connecting elements (24) associated with the respective outputs (UT1-UT8), said microcomputer (22) generating, in response to input signals correspond¬ ing to the function of the different lighting points of the traction vehicle, output signals (S D ) which cause the corresponding connecting element (24) to apply a voltage (U) to a given output (UT1-UT8) connected to the corresponding lighting point of the trailer. 2. A connecting device as claimed in claim 1, c h a r a c t e r i s e d in that voltages generated in the traction vehicle (2) for switching on corresponding lighting points on the trailer are supplied to a signal adapter (30) whose output signals are transmitted to the microcomputer (22) for connecting the corresponding lighting point of the trailer. 3. A connecting device as claimed in claim 1 or 2, c h a r a c t e r i s e d in that the connecting ele¬ ments (24) consist of relays, a movable relay contact (26) of each relay connecting, when in released position, an output (UT1-UT8) of the trailer contact (20) to earth and connecting, when in operative position, this output (UT1-UT8) to a supply voltage (U). 4. A connecting device as claimed in claim 3, c h a r a c t e r i s e d in that a current limiter (28) is connected between the voltage source (U) and each relay (24). 5. A connecting device as claimed in claim 4, c h a r a c t e r i s e d in that the current limiter (28) generates an output signal (S κ ) if the associated output (UT1-UT8) is short-circuited when the relay (24) is in operative position, said output signal (S κ ) being sup¬ plied to the microcomputer (22) which in response thereto brings the corresponding relay (24) to released position. 6. A connecting device as claimed in any one of claims 1-5, c h a r a c t e r i s e d by an input (P) for connecting a programming unit (32) by means of a cable (34), said programming unit (32) having a program selector (44) enabling sequential connection of each connecting element (24) for matching a lighting point (8L, 8R) on the traction vehicle (2) to the corresponding lighting point of the trailer, and storing the result in the microcom¬ puter (22). 7. A connecting device as claimed in any one of claims 1-5, c h a r a c t e r i s e d by an input (P' ) which on its internal side is connected to a receiver and on its external side is connected to an antenna (42' ) which receives radio signals transmitted via an antenna (42) by a transmitter in a programming unit (32') which has a program selector (44) enabling sequential connection of each connecting element (24) for matching a lighting point (8L, 8R) of the traction vehicle (2) to the corre- sponding lighting point of the trailer, and storing the result in the microcomputer (22). 8. A connecting device as claimed in any one of claims 1-7, c h a r a c t e r i s e d by a display unit (36) having a pair of visual control means (38, 40) asso¬ ciated with each connecting element (24), said microcom¬ puter (22) activating either a first control means (38) in response to the activation of the corresponding connecting element, or a second control means (40) in response to a detection of a short circuit of the corresponding connect¬ ing element (24). 9. A connecting device as claimed in claim 8, c h a r a c t e r i s e d by an acoustic signal replac¬ ing/supplementing the activation of either or both of the control means (38, 40). 10. A connecting device as claimed in claim 8 or 9, c h a r a c t e r i s e d in that the visual control means (38, 40) are light-emitting diodes, said first con¬ trol means (38) preferably emitting green light and said second control means (40) preferably emitting red light. AMENDED CLAIMS [received by the International Bureau on 29 July 1992 (29.07.92) ; original claim 1 amended ; claim 3 replaced by amended claim 2 ; claims 2 and 4 replaced by amended claim 3 ; claims 5-10 replaced by amended claims 4-9 ( 3 pages)] 1. A connecting device (18) with a number of inputs (IN) and a number of outputs (OUT, P) for interconnec¬ ting lighting points of a traction vehicle (2) and cor¬ responding lighting points of a trailer, said traction 5 vehicle (2) having a cable trunk (4) connected to a fuse holder (6) , different lighting points (8L, 8R) and a trailer contact (12) , wherein an additional cable trunk (14, 14') is connected to. he fuse holder (6) and an ad¬ ditional trailer contact (20) having a number of outputs 10 (UT1-UT8) and adapted to be connected to the contact me¬ ans of the trailer to transmit a voltage to the diffe¬ rent lighting points of the trailer, and wherein at le¬ ast some of said inputs and outputs (IN, OUT) are con¬ nected to the cable trunk (4; 14, 14'), characteri- 15 sed in that the connecting device (18) includes a mi¬ crocomputer (22) and a number of connecting elements (24) associated with the respective outputs (UT1-UT8) , said microcomputer (22) generating, in response to input signals corresponding to the function of the different 20 lighting points of the traction vehicle, output signals (So) which cause the corresponding connecting element (24) to apply a voltage (U) to a given output (UT1-UT8) connected to the corresponding lighting point of the trailer. 25 2. A connecting device as claimed in claim 1, characterised in that the connecting elements (24) consists of relays, a movable relay contact (26) of each relay connecting, when in released position, an output (UT1-UT8) of the trailer contact (20) to earth and con- 0 necting, when in operative position, this output (UT1- UT8) to a supply voltage (U) . 3. A connecting device as claimed in claim 2, characterised in that voltages generated in the traction vehicle (2) for switching on corresponding lighting points on the trailer are supplied to a signal adapter (30) whose output signals are transmitted to the microcomputer (22) for connecting the corresponding lighting point of the trailer, and that a current limi- ter (28) is connected between the voltage source (U) and each relay (24) . 4. A connecting device as claimed in claim 3 , characterised in that the current limiter (28) ge¬ nerates an output signal (SR) if the associated output (UT1-UT8) is short-circuited when the relay (24) is in operative position, said output signal (S κ ) being supp¬ lied to the microcomputer (22) which in response thereto brings the corresponding relay (24) to released posi¬ tion. 5. A connecting device as claimed in any one of claims 1-4, characterised by an input (P) for con¬ necting a programming unit (32) by means of a cable (34) , said programming unit (32) having a program selec¬ tor (44) enabling sequential connection of each connec- ting element (24) for matching a lighting point (8L, 8R) on the traction vehicle (2) to the corresponding ligh¬ ting point of the trailer, and storing the result in the microcomputer (22) . 6. A connecting device as claimed in any one of claims 1-5, characterised by an input (P•) which on its internal side is connected to a receiver and on its external side is connected to an antenna (42*) which receives radio signals transmitted via an antenna (42) by a transmitter in a programming unit (32') which has a program selector (44) enabling sequential connection of each connecting element (24) for matching a lighting point (8L, 8R) of the traction vehicle (2) to the corre¬ sponding lighting point of the trailer, and storing the result in the microcomputer (22) . 7. A connecting device as claimed in any one of claims 1-6, characterised by a display unit (36) having a pair of visual control means (38, 40) associ¬ ated with each connecting element (24) , said microcompu¬ ter (22) activating either a first control means (38) in response to the activation of the corresponding connec- ting element, or a second control means (40) in response to a detection of a short circuit of the corresponding connecting element (24) . 8. A connecting device as claimed in claim 7, characterised by an acoustic signal repla- cing/supplementing the activation of either or both of the control means (38, 40). 9. A connecting device as claimed in claim 7 or 8, characterised in that the visual control means (38, 40) are light-emitting diodes, said first control means (38) preferably emitting green light and said se¬ cond control means (40) preferably emitting red light.

Inventors: FUNDIN KJELL RUNE, FUNDIN, KJELL, RUNE
Applicants: FUNDIN KJELL RUNE, FUNDIN, KJELL, RUNE
Application year: 1992
Main classification: B60D1
IPC codes: B60R16