GB2592084A - Safety feature for a vehicle trailer - Google Patents

Abstract

A trailer 130 is provided for being towed by a tractor unit 120 which provides command signals to trailer 130 through one or more couplings 200 on the trailer to operate trailer safety functions. Trailer 130 has a control unit configured to operate safety functions of the trailer independent of couplings 200 and to operate safety feature lights which are present in parallel to safety feature lights operable by signals from the tractor unit via couplings 200. The safety feature lights are provided power in parallel to existing lighting units. The safety features can be both brake lights and indicator lights. A diode arrangement, for example two forward-biased diodes in parallel, may be provided to prevent power applied from the control unit being fed to tractor unit 120.

Description

Safety feature for a vehicle trailer The present invention relates to a safety feature for a vehicle trailer, particularly for a truck trailer arid in particular to increase safety upon failure of any coupling between) the tractor unit and a trailer, such as in an articulated vehicle arrangement.

A common feature of road transport is a tractor unit with an articulated trailer. Trailers are desired to couple to trucks by means of a common format of fifth wheel coupling enabling a given tractor unit to readily couple and decouple from trailers. Separate coupling means is provided by means of electrical and pneumatic connections such as to connect lights and brakes of the trailer to the tractor unit.

A large number of feet safety features have been introduced to ensure that the coupling between the tractor unit and the trailer both mechanically; electrically, hydraulically and pneumatically is robust and failsafe features are widely available.

US 5,442,332 discloses an inertial sensor unit for use in a first vehicle towing a second vehicle to actuate brakes or a vehicle light, that light being a brake light or an indicator light.

US 5,121,100 discloses a vehicle brake light operated by an inertial change.

DE 2,325,861 discloses a control box on a trailer so as to vary the intensity of trailer brake lights operated from a towing vehicle, depending upon the deceleration of the trailer.

There nevertheless remains scope for improving safety, in particular the coupling may suffer a partial or complete failure. lAihile some such failures can be catastrophic or failures can be mitigated and can in themselves if acted upon into drastic manner serve to reduce safety. By example the failure of a light cluster for giving information to following vehicles will reduce safety but in a situation, such as a high-speed or congested road it will likely be safer for the vehicle to continue at least until a place when a repair can be safely made rather than simply discontinuing travel. There is therefore a means to mitigate failure of the coupling between a tractor and a trailer unit without reducing safety.

The above considerations are applicable to various vehicle trailer arrangements.

The present invention provides a truck trailer for being towed by a tractor unit providing command signals to the trailer to operate trailer safety functions by means of one or more couplings, the trailer comprising: one or more couplings for receiving safety functions from a tractor unit configured to tow the trailer, a control unit configured to operate safety functions of the trailer independent of the one or more couplings, the control unit comprising an inertial measurement unit, the control unit being configured to compare the acceleration and deceleration of the trailer as determined by the inertial measurement unit with predetermined criteria for operating the safety functions of the trailer, wherein upon the predetermined criteria being met the control unit is configured to operate the one or more safety functions of the trailer.

The preferred safety function of the present invention implemented by the control unit is the operation of a brake light or indicator light.

A brake light is typically a light or light cluster attached to a rear panel of the trailer to be illuminated upon application of the brakes of the vehicle. However, the function of such lights is to indicate to following traffic that the vehicle is decelerating. Such deceleration can also occur by means of engine braking, in which the friction brakes of the vehicle are not applied but the engine is used to slow down the vehicle the importance of the deceleration to following traffic is not dependent upon the source of the deceleration but on its consequences, i.e. the rate of deceleration is duration et cetera. Therefore, occasion arises when brake lights are not illuminated even though deceleration equivalent to breaking via friction brakes is applied. The present invention therefore preferably acts to implement a safety function of operation of the brake light upon deceleration of the trailer and can do so irrespective of the integrity of function or signals from the coupling to a tractor unit. This provides a significant safety advantage. More conventionally, should the electrical wiring, can bus or other communication from the tractor unit fail this may not warrant an immediate stop, such as on a busy highway and the present invention enables the safety function of the stop lights to operate successfully in the absence of such communication.

The relevant deceleration for brake lights is deceleration of the vehicle relative to the longitudinal axis of the trailer.

The safety feature lights operated by the present invention may preferably be present in parallel to safety feature lights operated by signals from the tractor unit via the coupling. This means that, for example a short circuit in the trailer unit part of the tractor unit coupling still allows the safety feature to operate independently. However, the safety feature lights of the present invention may provide power in parallel to existing lighting units, preferably this is achieved by means of a diode arrangement such that power applied independently from the control unit is not diverted back through to the connection to the tractor unit, this is particularly advantageous as it avoids overloading any tractor unit control function and obviates any issue with a short circuit in circuitry up until the actual lighting unit itself. Two forward biased diodes in parallel, each being fed by the respective circuitry mentioned above and both connecting to the light cluster would achieve this.

For the above reasons the safety unit being a brake light may be preferred.

The safety unit may be an indicator light. On many vehicles indicator lights to indicate a change of direction to following traffic, but also potentially for traffic in parallel to the vehicle, such as by side mounted indicator lights, is activated by a separate switch operable by a driver. This can mean that a driver may fail to operate developments which even when carrying out manoeuvre were following traffic would benefit from a warning that the vehicle was changing direction.

An indicator light is typically a light or light cluster attached to a rear panel, and potentially along the sides, of the trailer to be illuminated upon application activation of an indicator switch operated by a driver. However, the function of such lights is to indicate to following traffic that the vehicle is turning about to turn and is largely at the discretion of the driver, the driver may make errors. Such turning can also occur by due to swerving to avoid an obstacle and the timeframe in which this occurs may not enable an indicator light to be successfully activated before the event. The importance of the turning to following traffic is not dependent upon the source of the turning but on its consequences, i.e. the rate of deceleration its duration et cetera. Therefore, an occasion arises when indicator lights are not eliminated even though turning is taking place. The present invention therefore preferably acts to implement a safety function of operation of the indicator light upon lateral acceleration of the trailer and can do so irrespective of the integrity of function or signals from the coupling to a tractor unit. This provides a significant safety advantage. More conventionally, should the electrical wiring, CAN bus or other communication from the tractor unit fail this may not warrant an immediate stop, such as on a busy highway and the present invention enables the safety function of the indicator lights to operate successfully in the absence of such communication.

As will be appreciated indicator lights are typically provided on port and starboard sides a trailer (left and right) as looking from the rear of the trailer towards the front of the trailer and the present invention specifically includes this eventuality. The relevant lateral acceleration being related to the relevant movement to port or starboard.

The skilled person will appreciate that depending upon the placement of the inertial measurement unit the magnitude and direction of the acceleration will change and the thresholds required by the present invention can be readily determined by practical measurements by attaching a control unit to the trailer towed by truck and obtaining relevant measurements to establish the thresholds. The absolute magnitude thresholds will depend upon traffic regulations and environmental conditions and to specify these would unduly limit the scope of the invention.

The relevant acceleration for indicator lights is acceleration of the vehicle relative to the transverse axis of the vehicle (i.e. laterally).

The control unit is preferably placed at the front end of the trailer when monitoring indicator lights. This provides the maximum detectable acceleration, and hence the maximum potential sensitivity to be detected by the inertial measurement unit. For these purposes the front end of the trailer is the portion of the trailer forward of the foremost wheels of the trailer, however most preferably it is the foremost portion of the trailer body, such as a front panel.

The control unit is preferably placed in direct mechanical communication with axles of wheels of the trailer when monitoring brake lights. This provides the maximum detectable deceleration, at least from friction braking as it decouples the effect of suspension units between the axles and the body of the trailer. The control unit is preferably placed in direct mechanical communication with the kingpin of any fifth wheel coupling of a trailer. This enables deceleration of the tractor unit relative to the trailer to be most readily detected as they play in the kingpin relative to the fifth wheel will be most readily transmitted to the inertial measurement unit at this point.

When the safety function/features require optimum placement in different places then the control unit may comprise a separate control unit, each comprising an inertial measurement unit placed in the relevant optimum position as described above. Such units may operate in concert or may operate entirely independently, the latter is preferable as ii provides a further degree of isolation of the functions such that any damage to one system is unlikely to impact the other.

The present invention preferably comprises the safety features of brake lights and indicator lights and the control unit comprising the inertial measurement unit is preferably placed at between the kingpin and the front of the body of the trailer, when an articulated trailer is used.

The benefits of the invention are primarily present when there is a coupling between the tractor and the trailer as the coupling (for providing signals, commands or controls relevant to safety features) is a particular weak point in tractor and trailer systems.

The present invention may be implemented in a truck trailer, that is a trailer of significant size for use as part of a commercial vehicle. These trailers are particularly vulnerable because of the size, weight, inertia and the inability to see lights of the tractor unit which may be obscured due to the trailer, this was particularly the case with an articulated tractor unit (e.g. a 'semi'). in the present invention the term safety feature and safety function are synonymous.

The term direct mechanical communication means a direct link, absent any resilient member between the named functions. Since even rigid members may have a degree of resilient deformation, such as rigid steel joist forming the backbone of a truck trailer, then direct communication will normally also require physical proximity within 1 m, preferably 10 cm when particularly when connected by metallic connections.

The present invention includes the schematic diagram presented as figure 1 Figure 1 comprises numbered features related to features of the present invention, these numbered features are 120, 130, 140, 300, 400, 410, 420, 500.

Claims (7)

1. Claims, 1. A trailer for being towed by a tractor unit providing command signals to the trailer to operate trailer safety functions by means of one or more couplings, the trailer comprising: one or more couplings for receiving safety functions from a tractor unit configured to tow the trailer, a control unit configured to operate safet functions of the trailer independent of the one or more couplings, the control unit being configured to operate safety feature lights present in parallel to safety feature lights operable by signals from the tractor unit via the coupling, wherein, the safety feature lights are provided power in parallel to existing lighting units.
2. 2. The trailer of claim 1, wherein the operation of safety feature lights is achieved by means of a diode arrangement such that power applied independently from the control unit is not diverted back through to the connection to the tractor unit.
3. 3. The trailer of claim 2; wherein said diode arrangement comprises two forward biased diodes in parallel; each being fed by their respective circuitry to a brake light or indicator light of a light duster to implemented operation of a brake light or indicator light by the control unit.
4. 4. The trailer of claim 3; wherein the safety function comprises safety feature lights operated by the control unit are in parallel to safety feature lights operated by signals from the tractor unit to which the trailer is configured to be connected by means of the coupling.
5. 5. The trailer of claim 3 or 4 wherein the safety feature lights are brake lights.
6. 6. The trailer of any of claims 2, 3 or 4 when the safety feature lights are indicator lights.
7. 7. The trailer of any of claims 1 to 6 wherein the safety features are both brake lights and indicator lights.