GB1575538A

GB1575538A - Indicating apparatus for tractors of tractor-trailer combination vehicles in which at least the tractor is provided with an anti-locking brake regulating system

Info

Publication number: GB1575538A
Application number: GB3354277A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1976-09-08
Filing date: 1977-08-10
Publication date: 1980-09-24
Also published as: DE2640355C2; JPS6133723B2; JPS5334208A; FR2364145A1; SE7710025L; SE413487B; FR2364145B1; DE2640355A1

Description

(54) INDICATING APPARATUS FOR TRACTORS OF TRACTOR TRAILER COMBINATION VEHICLES IN WHICH AT LEAST THE TRACTOR IS PROVIDED WITH AN ANTI-LOCKING BRAKE REGULATING SYSTEM (71) We, ROBERT BOSCH GMBH, a German company of Postfach 50, 7000 Stuttgart 1, Germany., do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to indicating apparatus for a tractor of a tractor-trailer combination vehicle for indicating to the driver when he is pulling a trailer which has no or no normally operating anti-locking brake regulating apparatus.

Indicating apparatus has already been proposed in which a current measuring device is used in a supply line for the trailer antilocking brake regulating system, wherein use is also made of a special plug-in unit between the tractor and the trailer, in which a switch contact is arranged which is opened or closed depending on whether or not a trailer is attached. The switching signal which is conveyed from the switch contact of the plug-in unit and the output signal from the current measuring device are combined with one another and with a particular combination of the said two signals, the tractor anti-locking regulating system is switched off.With this solution, it is disadvantageous on the one hand that the tractor anti-locking regulating system operating normally is switched off and that a special plug-in unit provided with a switch contact must be used between the tractor and the trailer.This is laborious and expensive, furthermore such plug-in units are prone to failure and do not therefore serve for increasing the operational safety.

The present invention provides indicating apparatus for a tractor of a tractor-trailer combination vehicle in which at least the tractor is provided with an anti-locking brake regulating system, comprising a first current measuring device in a supply line from an operating voltage supply to a plug-in unit for a trailer anti-locking brake regulating system, a second current measuring device is arranged in a supply line from the operating voltage source to a plug-in unit for the brake light equipment of the trailer, a logic circuit arranged to receive signals provided by the current measuring devices, and an indicating device responsive to an output from the logic circuit, which logic circuit is arranged to activate the indicating device when the trailer is attached to the tractor but has no or no normally operating anti-locking brake regulating system.

An advantage of a preferred embodiment of the present invention is that the tractor antilocking brake regulating system remains switched on, but on each braking operation a warning indication draws the attention of the driver of the tractor to the inherent critical condition that the trailer of the tractor has no antilocking regulating system and that, for that reason, dangerous travelling situations can occur, for example, breaking loose of the trailer or displacement of the trailer in the traffic lane. Moreover, the apparatus has the advantage that no special plug-in devices are required between the tractor and the trailer and that a warning does not take place when the trailer is provided with an anti-locking brake regulating device or when the tractor travels without a trailer.

In order that the present invention be more readily understood, an embodiment thereof will now be described by way of example with reference to the accompanying drawing, which shows a circuit diagram of indicating apparatus.

Indicating apparatus for tractors of articulated vehicles is illustrated in the drawing.

The part of the circuit represented to the left of the dotted line is located on the tractor, the part of the circuit represented to the right of the dotted line is located on the trailer. A supply line 10 is illustrated on the tractor side, from a supply voltage source (not shown) to a plug-in device 11 which has a counterpart 12 on the trailer side. A current measuring device 13, in the simplest case a resistor, is arranged in the supply line. When the plug 11 is connected to the socket 12 and a current flows to the normally operating trailer-anti-locking regulating system, a voltage drop occurs at the resistor 1 3 which represents a binary switching signal namely a logic 1. Furthermore, a supply line 14 is provided on the tractor from the supply voltage source (not shown) to a plug-in device which has a socket on the trailer side.A brake lighting system 17 for the trailer is connected to the said socket 16. If the brake actuated, with a trailer attached, a current flows to the brake lighting system 17 for the trailer and a voltage drop occurs at a current measuring device 18 in the supply line 17, which represents a binary switching signal, namely a logic 1, as with the current measuring device 13. The two current measuring device 13 and 18 are each connected to a threshold switch 19 or 20. The output from the threshold switch 19 is connected to the inverting input of an AND-gate 21 as well as to the non-inverting input of an AND-gate 22. The output from the threshold switch 20 is connected to a noninverting input of the AND-gate 21 as well as to inverting input of the AND-gate 22. Similarly, a brake light switch referenced 23 is connected to a non-inverting input of the ANDgate 22.

The outputs from the two AND-gates 21 and 22 are connected to an astable trigger 25 through an OR-gate 24 whereby the astable trigger 25 causes a warning lamp 26 and/or an acoustic warning device to respond.

The method of operation of the switching arrangement described is as follows.

Case A: An articulated vehicle comprising a tractor and a trailer is considered, both of which are provided with a functioning antilocking regulating system. In this case, a current flows not only through the supply line 10 but also through the supply line 14 during braking.

A logic 1 appears at the inverting input to the AND-gate 21, likewise at the non-inverting input, so that at the output there appears a logic 0. A logic 1 is applied to the inverting input of the AND-gate 22, likewise to the two non-inverting inputs. Thus, a logic 0 is present at the output from the AND-gate, or OR switch 24 is blocked and the warning lamp 26 does not light up. Advantageously in the present case, a defect in the current circuit to the brake light equipment of the trailer is also displayed when the brake light switch 23 is actuated. Thus, the driver of the vehicle can be made aware, for example, of an improperly plugged in supply line or even of a defective bulb in the brake light.

Case B: It is assumed that the tractor is provided with an anti-locking regulating system, but that the trailer has no, or no normally functioning, anti-locking regulating system. No current flows in the supply line 10. On the other hand, a current flows in the supply line 14 during braking. A logic 0 is applied to the inverting input to the AND-gate 21, a logic 1 is applied to the non-inverting input. A logic 1 is applied to the inverting input to the ANDgate 22, a logic 0 is applied to the first noninverting input to the AND-gate 22 and a logic 1 to the second non-inverting input thereof.

A logic 1 is produced at the output from the AND-gate 21 and a logic 0 is produced at the output from the ANDgate 22. Due to these output signals, the OR-gate 24 becomes conductive and the warning lamp lights up during braking.

Case C: It is assumed that a tractor is travelling without a trailer. In this case, no current flows either in the supply line 10 or in the supply line 14. A logic 0 is applied to the inverting input to the AND-gate 21 and a logic 0 is also applied to the non-inverting input to the AND-gate. Thus, the output signal from the AND-gate 21 will be 0. A logic 0 is applied to the inverting input to the ANDgate 22, likewise to the first inon-inverting input, whilst a logic 1 is applied to the second non-inverting input. In this manner, a logic 0 is produced at the output from the AND-gate 22, the OR- gate 24 remains blocked and the warning lamp 26 is not switched on.

The situation is achieved that a timed antilocking regulating system on a tractor does not have to be put out of action when a trailer which is not protected against locking is coupled thereto or when a trailer which itself is protected against locking has been put out of action by an operational defect in its own anti-locking regulating apparatus. At the same time, on each braking operation, the driver of the vehicle is made ware of this inherently undesirable travelling condition by a warning indication.

WHAT WE CLAIM IS: 1. Indicating apparatus for a tractor of a tractor-trailer combination vehicle in which at least the tractor is provided with an antilocking brake regulating system, comprising a first current measuring device in a supply line from an operating voltage supply to a plugin unit for a trailer anti-locking brake regulating system, a second current measuring device arranged in a supply line from the operating voltage source to a plug-in unit for the brake light equipment of the trailer, a logic circuit arranged to receive signals provided by the current measuring devices, and an indicating device responsive to an output from the logic circuit, which logic circuit is arranged to

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. Indicating apparatus for tractors of articulated vehicles is illustrated in the drawing. The part of the circuit represented to the left of the dotted line is located on the tractor, the part of the circuit represented to the right of the dotted line is located on the trailer. A supply line 10 is illustrated on the tractor side, from a supply voltage source (not shown) to a plug-in device 11 which has a counterpart 12 on the trailer side. A current measuring device 13, in the simplest case a resistor, is arranged in the supply line. When the plug 11 is connected to the socket 12 and a current flows to the normally operating trailer-anti-locking regulating system, a voltage drop occurs at the resistor 1 3 which represents a binary switching signal namely a logic 1. Furthermore, a supply line 14 is provided on the tractor from the supply voltage source (not shown) to a plug-in device which has a socket on the trailer side.A brake lighting system 17 for the trailer is connected to the said socket 16. If the brake actuated, with a trailer attached, a current flows to the brake lighting system 17 for the trailer and a voltage drop occurs at a current measuring device 18 in the supply line 17, which represents a binary switching signal, namely a logic 1, as with the current measuring device 13. The two current measuring device 13 and 18 are each connected to a threshold switch 19 or 20. The output from the threshold switch 19 is connected to the inverting input of an AND-gate 21 as well as to the non-inverting input of an AND-gate 22. The output from the threshold switch 20 is connected to a noninverting input of the AND-gate 21 as well as to inverting input of the AND-gate 22. Similarly, a brake light switch referenced 23 is connected to a non-inverting input of the ANDgate 22. The outputs from the two AND-gates 21 and 22 are connected to an astable trigger 25 through an OR-gate 24 whereby the astable trigger 25 causes a warning lamp 26 and/or an acoustic warning device to respond. The method of operation of the switching arrangement described is as follows. Case A: An articulated vehicle comprising a tractor and a trailer is considered, both of which are provided with a functioning antilocking regulating system. In this case, a current flows not only through the supply line 10 but also through the supply line 14 during braking. A logic 1 appears at the inverting input to the AND-gate 21, likewise at the non-inverting input, so that at the output there appears a logic 0. A logic 1 is applied to the inverting input of the AND-gate 22, likewise to the two non-inverting inputs. Thus, a logic 0 is present at the output from the AND-gate, or OR switch 24 is blocked and the warning lamp 26 does not light up. Advantageously in the present case, a defect in the current circuit to the brake light equipment of the trailer is also displayed when the brake light switch 23 is actuated. Thus, the driver of the vehicle can be made aware, for example, of an improperly plugged in supply line or even of a defective bulb in the brake light. Case B: It is assumed that the tractor is provided with an anti-locking regulating system, but that the trailer has no, or no normally functioning, anti-locking regulating system. No current flows in the supply line 10. On the other hand, a current flows in the supply line 14 during braking. A logic 0 is applied to the inverting input to the AND-gate 21, a logic 1 is applied to the non-inverting input. A logic 1 is applied to the inverting input to the ANDgate 22, a logic 0 is applied to the first noninverting input to the AND-gate 22 and a logic 1 to the second non-inverting input thereof. A logic 1 is produced at the output from the AND-gate 21 and a logic 0 is produced at the output from the ANDgate 22. Due to these output signals, the OR-gate 24 becomes conductive and the warning lamp lights up during braking. Case C: It is assumed that a tractor is travelling without a trailer. In this case, no current flows either in the supply line 10 or in the supply line 14. A logic 0 is applied to the inverting input to the AND-gate 21 and a logic 0 is also applied to the non-inverting input to the AND-gate. Thus, the output signal from the AND-gate 21 will be 0. A logic 0 is applied to the inverting input to the ANDgate 22, likewise to the first inon-inverting input, whilst a logic 1 is applied to the second non-inverting input. In this manner, a logic 0 is produced at the output from the AND-gate 22, the OR- gate 24 remains blocked and the warning lamp 26 is not switched on. The situation is achieved that a timed antilocking regulating system on a tractor does not have to be put out of action when a trailer which is not protected against locking is coupled thereto or when a trailer which itself is protected against locking has been put out of action by an operational defect in its own anti-locking regulating apparatus. At the same time, on each braking operation, the driver of the vehicle is made ware of this inherently undesirable travelling condition by a warning indication. WHAT WE CLAIM IS:

1. Indicating apparatus for a tractor of a tractor-trailer combination vehicle in which at least the tractor is provided with an antilocking brake regulating system, comprising a first current measuring device in a supply line from an operating voltage supply to a plugin unit for a trailer anti-locking brake regulating system, a second current measuring device arranged in a supply line from the operating voltage source to a plug-in unit for the brake light equipment of the trailer, a logic circuit arranged to receive signals provided by the current measuring devices, and an indicating device responsive to an output from the logic circuit, which logic circuit is arranged to

activate the indicating device when the trailer is attached to the tractor but has no or no normally operating anti-locking brake regulating system.

2. Apparatus according to claim 1, wherein the current measuring devices comprise resistors in the supply lines wherein the voltage drop occuring at the resistors is evalued.

3. Apparatus according to claim 1 or 2, wherein each current measuring device is associated with a threshold value switch wherein the outputs from the threshold value switch are connected to the logic circuit.

4. Apparatus according to any one of claims 1 to 3 wherein the indicating device comprises a warning lamp and/or an acoustic signal generator, which is actuated by the logic circuit device through an astable trigger.

5. Apparatus according to one of claims 1 to 4 characterised in that the logic circuit is arranged to actuate the warning device during a braking operation.

6. Indicating apparatus substantially as hereinbefore described with reference to the accompanying drawing.