Claas has introduced what it terms an 'automatic trailer stretch brake' option for its Arion tractors equipped with CMATIC constantly variable transmission. Available for the mid-range Arion 500/600 series tractors with CVT and air brakes, it is claimed to relieve the burden on the driver in difficult conditions such as driving heavy trailers downhill, or working with balers and crop sprayers on sloping ground.

Detection of hazardous situation

The system automatically activates the trailer’s air brakes as soon as predetermined forces are exerted on the tractor. These critical pressures could potentially result in the trailer jack-knifing with unfortunate consequences.

The system operates using sensors in the transmission to record engine torque and transmission loads going through the drive train.

The driver can actively increase the braking action of the combination when driving by pulling back the drive lever in 'auto' mode. This increases deceleration by reducing the transmission ratio and increasing the engine speed to match the forward speed.
Claas with stretch brake
The air brake is engaged automatically to reduce the trailer’s ground speed and 'stretch' the tractor-trailer combination to achieve maximum deceleration. The system also automatically activates the trailer’s air brakes as soon as dangerous thrust forces are detected by the tractor.

Working in conjunction with cruise control

The automatic trailer-stretch function can also be used with active cruise control speeds of up to maximum 20km/h. On slight slopes and with lights loads, the cruise control speed is automatically maintained by activating the pneumatic trailer brakes. On steeper gradients with heavy loads, excess speed over that of the set speed may be reduced.
Slurry spreading on slope
This function can be used when working on slopes with square balers or trailed crop sprayers, providing an enormous safety boost in addition to significantly reducing the driver's workload.

Cadence braking by Claas

The automatic trailer stretch brakes also assist with reversing trailers by triggering the braking action as soon as the driver initiates a change in direction using the reversing or control lever.

The pulsing action of the brakes effectively prevents overheating and reduces the risk of wheel lock with automatic braking assistance.

The automatic trailer stretch brake is available from summer 2021 and can be retrofitted to Arion 500/600 series tractors built from 2021 onwards.