GB2470610A

GB2470610A - Angle sensor monitoring system for trailer towing vehicles

Info

Publication number: GB2470610A
Application number: GB0909375A
Authority: GB
Inventors: John Paul Standen
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-05-30
Filing date: 2009-05-30
Publication date: 2010-12-01
Also published as: GB0909375D0

Abstract

A system for measuring the angle of a trailer relative to a towing vehicle whereby the sensing means do not output an angle signal until the angle sensing device is properly engaged with the mating part of the trailer, thereby eliminating the output of erroneous signals and also offering benefits regarding a trailer coupling monitoring system. The device is typically mounted within a fifth wheel assembly and engages with a semi-trailer king pin 1. The device comprises an angle sensor body 4, an angle sensor shaft 3 coupled to a rotatable cup 2, detector means 6 and a control system 5.

Description

Angle Sensor Monitoring System for Trailer Towing Vehicles

Field of the Invention

This invention relates to a device which measures the angle between a towing vehicle and trailer which automatically avoids outputting incorrect trailer angle information during trailer coupling and uncoupling or when a towing vehicle is operated without a trailer.

Background to the Invention

Articulated vehicles comprising a tractor unit and semi-trailer are typically coupled together by means of a king-pin extending downwards from the underside of the semi-trailer which engages and locks within a fifth-wheel mechanism attached to the tractor unit, the locking method comprising a fixed socket within the fifth-wheel and moveable jaws which encircle the semi-trailer king-pin and lock closed to retain it within the socket.

A release arm is provided to unlock the jaws and allow the king-pin to exit the fifth-wheel socket to uncouple the semi-trailer from the tractor unit.

Many methods of measuring the angle of a semi-trailer relative to a tractor unit are known and these angle sensors are commonly intended to provide a signal which can be used to automatically adjust the position of a rear view mirror, thereby enabling the driver to maintain visibility of the rear corner of the semi-trailer during turns.

A problem associated with previously known semi-trailer angle sensing methods is that they may provide spurious signals when a trailer is not connected, thereby causing the rear view mirror to adjust to an incorrect position. Depending on the type of semi-trailer angle sensor used, spurious angle signals may occur due to vibration whilst the tractor unit is being driven without a semi-trailer attached or may occur when the semi-trailer is being coupled to, or uncoupled from, the tractor unit. One method of avoiding incorrect mirror alignment when no semi-trailer is coupled to the tractor unit is to provide a bypass control which the driver can operate to cause the system to ignore the angle sensor output, this has the disadvantage that the driver may forget to operate the bypass control and thereby a dangerous situation could occur as the driver's field of view via the mirror was not as expected. A further method of avoiding incorrect mirror alignment when no semi-trailer is coupled to the tractor unit is to use a sensor monitoring the fifth-wheel lock mechanism to cause the mirror control system to ignore the semi-trailer angle sensor output when the fifth-wheel mechanism is unlocked, whilst eliminating the possibility of driver error this method has the disadvantage that the fifth-wheel might not be fitted with a suitable lock sensor or even if it is it might not be possible to monitor the required signal from within that system. A further disadvantage of using a fifth-wheel locking sensor to enable a mirror control system's use of a semi-trailer angle sensor's output is that if the angle sensor has not correctly connected with the mating part of the trailer the output signal may be incorrect and the mirror control system will therefore provide the

driver with an incorrect field of view.

Summary of the Invention

Accordingly, the present invention provides a system for measuring the angle of a trailer relative to a towing vehicle whereby the system does not output an angle signal other than one representing the towing vehicle and trailer being in a straight position until the trailer angle sensor is correctly coupled to the mating part of the trailer, thereby eliminating the output of erroneous signals.

Brief Description of the Drawings

The drawing illustrate exemplary embodiments of various aspects of the invention in conjunction with a semi-trailer angle sensor which mounts within a fifth-wheel mechanism and directly measures the rotational angle of the semi-trailer's king pin relative to the fifth-wheel. This type of trailer angle sensor is previously known from PCT/GBO3/00781 which describes a method by which rotational movement of a semi-trailer king pin can be monitored.

In the drawings, which illustrate exemplary embodiments of various aspects of the invention: Figure 1 is a schematic view of the functional elements required to realize the benefits of the invention; Figure 2 is a schematic view of an embodiment of the invention which uses magnets to assist with coupling the sensor to the king pin and also to enable angular sensing and king pin proximity sensing; and Figure 3 is a schematic view of a system similar to that in Figure 2 but incorporating a separate method of king pin proximity sensing.

Detailed Description of the Illustrated Embodiments Figure 1 illustrates diagrammatically an embodiment of the invention in conjunction with a trailer angle sensor which mounts within the fifth-wheel mechanism and directly measures the rotational angle of the semi-trailer's king pin relative to the fifth-wheel. The end of semi-trailer king pin 1 is shown located within the dished area of rotatable cup 2 which is supported by mounting means (not shown) which allow the cup 2 to remain coaxially aligned with, and cause it to be pressed against, king pin 1. A small gap between the king pin 1 and mating parts is shown in the drawings to aid clarity. Angle sensor shaft 3 is coupled to the rotatable cup 2 and rotates relative to angle sensor body 4 so that a signal representing rotation of king pin 1 is transmitted to control system 5.

Detection means 6 provides control system 5 with a signal indicating the presence or absence of king pin 1 within the recess of recess of rotatable cup 2. Control system 5 is configured to ignore angle information from sensor 4 unless detection means 6 indicates that the king pin 1 is correctly located within rotatable cup 2. Detection means 6 may comprise any suitable method of determining the correct location of king pin 1 within rotatable cup 2, suitable methods include inductive proximity sensors, capacitive sensors and electro-mechanical switches. If detection means 6 comprises an inductive proximity sensor it will be beneficial to construct rotatable cup 2 from a non-magnetic material and it may be beneficial to construct rotatable cup 2 from more than one material, for example the central section could beneficially be made from a non-magnetic material such as aluminium and the outer rim section could beneficially be made from a hard wearing material such as steel which may be magnetic without detriment to the performance of an inductive proximity sensor within the non-magnetic central section.

Sensing means 6 will preferably be mounted on a non-rotating part of the device rather than on rotating cup 2 to simplify making connections between sensing means 6 and control system 5. Control system 5 may comprise any control method suited to achieving the functions described and the output (not shown) of control system 5 may comprise any form suited to interfacing with associated systems.

Figure 2 illustrates a further enhancement to the system shown in Figure 1 and described above. Permanent magnet 7 is located in rotatable cup 2 and attached to pole piece 8. Permanent magnet 9 is also located in rotatable cup 2 and is attached to pole piece 10 but is oriented with the opposite magnetic polarity to magnet 7. The central part of rotatable cup 2 is made from a non-magnetic material. Pole piece 8 and pole piece 10 have opposite magnetic polarity and are shaped to form a gap, across which a magnetic flux exists. The end of king pin 1 is shown engaged within the dished part of rotatable cup 2 and in this position the magnets 7 and 9 ensure the rotatable cup 2 is clamped firmly against the end of the king pin 1 by magnetic attraction. Rotation of king pin 1 causes the magnetic flux existing between pole piece 8 and pole piece 10 to also rotate and this rotational angle is measured by magnetic rotational encoder 11 which is immersed within the magnetic flux and has an output connected to control system 5.

Magnetic rotational encoders are well understood and suitable devices are available as integrated circuits. The strength of the magnetic flux existing between pole piece 8 and pole piece 10 will vary according to whether the king pin 1 is connected across magnets 7 and 8 or not. The magnetic rotational encoder 11 may be configured to monitor flux density and therefore may be used to detect the absence or presence of the king pin 1 within the recess of the rotatable cup 2.

Figure 3 illustrates an embodiment of the system substantially similar to the system illustrated in Figure 2 but with an additional sensor 12 added to detect the presence of a king pin 1 within the recess of the rotatable cup 2. Sensor 12 may be any form of sensor capable of detecting the presence of king pin 1. Sensor 12 is preferably an inductive sensor as this will allow mounting inside an internal recess of rotatable cup 2 as shown.

Sensor 12 is mounted on a non-magnetic pillar 13 protruding through the flux gap created by pole piece 8 and pole piece 10. Pillar 13 is mounted on the top side of printed circuit board 14. Rotational magnetic encoder 11 is shown mounted on the underneath surface of printed circuit board 14 and is still within the magnetic flux existing between pole piece 8 and pole piece 10. Printed circuit board 14 may beneficially be used to mount the components required by control system 5.

Claims

Claims 1. A device comprising means for measuring the angle between a towing vehicle and trailer and containing further means capable of monitoring if the towing vehicle and trailer are properly connected.
2. A device according to Claim 1 whereby the device does not output a signal indicating a change of trailer angle unless the device senses that the trailer is correctly engaged with the coupling apparatus of the towing vehicle.
3. A device according to Claim 1 whereby the device does not output a signal other than one which describes the towing vehicle and trailer as being in a straight position unless the device senses that the trailer is correctly engaged with the coupling apparatus of the towing vehicle.
4. A device according to Claim 1 capable of outputting a signal representing the angle between a towing vehicle and trailer.
5. A device according to Claim I capable of outputting a signal indicating coupled or uncoupled relationship between the towing vehicle and trailer.
6. A device according to Claim 1 capable of outputting both a signal representing the angle between a towing vehicle and trailer and a signal indicating a coupled or uncoupled relationship between the towing vehicle and trailer.
7. A device according to any previous claim wherein the towing vehicle is an articulated vehicle tractor unit and the trailer is a semi-trailer.
8. A device according to claim 12 wherein the device mounts within the fifth-wheel assembly and engages with the semi-trailer king pin.
9. A device according to claim 12 wherein the device monitors the position of the semi-trailer king pin within the fifth-wheel assembly.