Height control device

The present invention relates to a device for controlling the height of a load or a load carrier behind the cab of a truck.

Normally, after a tractor has been connected to a trailer or a load carrier on a truck has been replaced with another load carrier, the driver has to leave the cab and visually control the total height of the complete vehicle.

For safety and transport economy reasons it would be advantageous if the driver could get exact information about the total height of the complete vehicle without having to step out of the cab.

The purpose of the present invention is to obtain a device which can present, on a display on the dashboard of the vehicle cab, information about the height of the load or the load carrier behind the cab provided that the height exceeds the level of the cab roof or the level of a air deflector mounted on the roof. The total height of the cab is known and information about the height of a load or load carrier lower than the cab is less important.

This is obtained according to the present invention by means of a device which comprises power operated sensor means supported on the outside of the cab and height adjustable between predetermined upper and lower positions, said sensor means being adapted, during vertical scanning movement, to detect the maximum height of the load or load carrier behind the cab and to send signals representing said maximum height to an indicator inside the cab.

Most long haul trucks and trailers nowadays are provided with air deflectors on the cab roof and such air deflectors are often pivotally mounted and manually adjustable to adapt the height of the rear of the air deflector to the maximum height of the load

or load carrier in order to improve fuel economy. Manual adjustment of the air deflector is, however, a complicated procedure requiring that the driver climbs up a ladder on the back of the cab to get access to the air deflector.

In a further development of the device according to the invention for a cab, having on the roof an adjustably mounted air deflector, this deflector is provided with power operated adjusting means and the sensor means are supported on a rear portion of the air deflector. When the power operated means are activated to adapt the height of the rear edge of the air deflector to the maximum height of the load or load carrier this height will be detected by the sensor means.

By providing the air deflector with power equipment for adjusting the height, and mounting the height sensor means on the air deflector, simultaneous adjustment of the air deflector and detection of the maximum height will be obtained.

The invention will be described in more detail below with reference to the accompanying drawings, wherein

Fig. 1 is a schematic side view of an upper portion of a track or tractor cab,

Fig. 2 is a schematic front view of the cab in Fig. 1 and

Fig. 3 is a block diagram of a device according to the present invention.

In Fig. 1 and 2 a truck or trailer cab 1 is shown which on its roof 2 supports an air deflector 3. The air deflector is pivotallyjournalled at its front end portion to the cab roof 2. A pair of power operated jack devices 4 (only one shown) connect the rear portion of the air deflector 3 with the cab roof 2. The jack devices could be driven by electric motors or hydraulic piston- cylinder devices which, when operated, var- ies the inclination of the air deflector 3 relative to the cab roof 2 to adapt the height

of the rear edge 5 of the deflector 3 to the maximum height of a load on a trailer or load carrier (not shown) behind the cab 1.

On the deflector 3 at the mid-section of its rear edge 5 a sensor 6 is mounted. The sensor could be an IR-, ultrasonic or radar sensor which can detect objects in front of it. The sensor 6 is arranged and directed so that it can detect the highest point of an object within a predetermined distance behind the cab which in this case will be the highest point of a load or load carrier behind the cab 2.

In Fig. 3 a block diagram of the device and control circuit is shown which should be self-explanatory with the exception of "parameters to be set" which among others could be scanning speed and range of the sensor. The range in this case is preferably set to be between upper and lower end positions of the air deflector. As shown, the driver can chose between manual and automatic adjustment of the air deflector 3 to the height of the load or load carrier. When choosing automatic adjustment the air deflector will start scanning from a position where an object is detected within said range and then scan upwards until the object, i.e. the load or load carrier, is no longer detected.

Preferably the device according to the invention also incorporates a wireless remote control so that, when manual adjustment is chosen, the driver can adjust the air deflector at a distance from the vehicle to get a better overview.

When applying the height control device according to the present invention on a ve- hide which does not have an air deflector the sensor 6 could be mounted on a telescopic antenna.

In a further development, using a radar antenna and receiver, the height of objects at a predetermined distance in front of the vehicle is also detected. Such objects could, for example, be a tunnel entrance or an underpass.