Plow companion

Plow companion
Marginal Column

July 2016


Electronic hitch controls have been a core function for tractors for decades. They facilitate the work of farmers and increase productivity.

When tractors first came along, they enormously facilitated the work of the farmer. Nevertheless, there was still room for improvement in terms of soil cultivation. That's because, especially in changing soil conditions, the power of the engine did not fit the weight or the traction power requirement of the plow. Often the wheels simply slip or the engine stalled. In addition, the driver now had to constantly look over his shoulder to keep an eye on the plow. This made for unsafe, inefficient and uncomfortable work. And finally, the increasingly heavy attachments at the rear made the tractor vibrate on the way to the fields – and thoroughly shook the driver.

Bosch Rexroth solved such problems with various innovations:

1952 The first mechanical hitch control (MHC) automatically provides a constant working depth, as well as constant draft resistance, thanks to a mixture of traction and lifting work position. This improves the rear axle load, the plowed surface and the use of attachments without making adjustments for depth. The driver adjusts the hitch from the seat for the first time.

1979 The first electro-hydraulic hitch control (EHC) comes to market. Due to the development of the force-measuring bolt and a sophisticated control concept, the traction that the tractor needs to pull the attachment can be accurately measured and controlled. Incorporating electronic components in with the hydraulics brings more security and comfort by means of active vibration damping. It allows for more precise tillage and is more durable because the system has fewer wear parts. In the meanwhile, the EHC has become standard equipment for medium and large-sized tractors.

2001 With on-board electronics, hydraulics and electronics merge for the first time in a mechatronic component. The entire hitch control becomes more compact as a result.

2007 The EHR33-da double-acting control valve allows the hitch control to also be actively used for pressure-supported lowering of the plow. This is especially handy when the hitch is unloaded, temperatures are low and lighter equipment is used.

2014 The EHC-8 is brought to market. It is the robust solution for small tractors without a cab and became an alternative for regional markets where mechanical systems are still widespread, such as in India.