GB1426549A - Self-propelled root harvesters - Google Patents

Abstract

1426549 Self propelled root harvester RANSOMES SIMS & JEFFERIES Ltd 1 Nov 1973 [2 Nov 1972] 50587/72 Heading A1F [Also in Division B7] A self propelled beet harvester has front ground engaging steering wheels 6, and means to automatically control the steering so that the machine maintains alignment with the rows of beet being harvested. Probes 36, attached to a subframe 38 on horizontal pivots are situated to the rear of a topping unit 40 and pass on either side of the row of beet. Misalignment of the machine relative to the row causes one of the probes to be displaced vertically, this motion is detected by one of two proximity switches 32 which are in circuit with a solenoid operated hydraulic spool valve 22. The spool valve in turn controls a double acting ram 2, thereby turning the wheels 2 and realigning the machine. A second set of proximity switches 34 situated on the front axle are also in circuit with the spool valve and through it operate the ram to straighten the wheels after alignment. The ram also acts as a power assisted steering mechanism controlled by a steering wheel 20, a valve 18 controlling the flow of fluid to the ram. If the automatic aligning mechanism is not required, the probes may be lifted clear of the ground and the machine steered in the conventional manner. The flow of fluid between valve 18 and the ram may be cut off by a switch 42, the machine then being steered entirely by mechanical means using wheel 20. In another embodiment, the topping units are displaced transversely relative to the frame by hydraulic means in order to maintain alignment with the row of beet, as in Specification 1426550, switching means being provided to effect changeover between this topping control and the automatic steering.