Abstract: A steerable device for moving trailer type vehicles, for example in working and parking areas. The device includes an engine for driving at least one of the wheels, means for connecting the device to that part of a trailer type vehicle normally connected to the fifth wheel connection of a tractor unit, and tiller steering for turning a steerable wheel or wheels. The device also includes an air compressor driven by the engine and a flexible connection provided with a quick-release adaptor for coupling the air compressor to the braking system of a trailer type vehicle for releasing its brakes.

Abstract: The present invention provides in an agricultural ground treating device particularly but not exclusively a seed drill arranged to be towed over the ground and having a plurality of ground engaging implements, means for causing all of the implements to engage the ground with a substantially equal force.Preferably the means to equalizing the forces comprises a pivotal beam arrangement in which the implements are movably mounted on the chassis of the device and connected in pairs at each end of an associated balance beam, these balance beams are pivotally mounted at their mid points on respective ends of further balance beams which are mounted by their mid points at respective ends of yet further balance beams, and so on according to the number of implements on the device, the final balance beam or final pair of balance beams being connected to means on the chassis of the device for urging them, and the implements connected thereto towards the ground.