Stone Picker

tone Picker

(From article List of agricultural machinery)

A Stone Picker, also known as a Rock Picker, is a farm implement usually pulled behind a tractor, used to remove the top layer of soil to separate rocks and soil debris from good topsoil. A stone picker is similar in appearance and function to a rock rake; however, a stone picker generally digs to greater depths to remove stones and rocks.

Stone pickers are used primarily in farming and landscaping, where stones need to be removed from the soil and ground surface to prevent damage to other farm machinery (such as hay bailers, combines, and mowers), improve the soil for crop production, or improve the appearance of the ground surface in preparation for a lawn or golf course. Surface stones and large rocks often left from plowing can damage a hay bailer, the header or reciprocating knives on a combine (see Combine harvester), and blades on a Rotary mower. Farmland containing large quantities of rock instead of fine grains of soil do not as efficiently feed necessary minerals to the plants' root system, and thus are not as conducive to efficient crop production. Lawns or golf courses are more aesthetically pleasing with smooth surfaces. For these reasons, stone pickers serve a valuable function.

Four main components comprise most stone pickers: the digging teeth, conveyor system, sieve or screen, and stone bin. The digging teeth are at the leading edge of the stone picker and remove soil which is subsequently placed on the conveyor system. If the sieve is not combined with the conveyor system, the conveyor system transports the soil material to a vibrating sieve which permits the smaller soil particles to fall back to the ground; whereas, the stones and large rocks are transported to a bin or hopper for periodic dumping. Most types of stone pickers require a large tractor, generally over 100 horsepower, equipped with hydraulics and Power take-off driven mechanisms. The tractor's hydraulics control the depth to which the stone picker digs to excavate soil material; whereas, the PTO controls the movement of the conveyor and screening system.

Common brands of stone pickers include Harley (currently out of production), Cherrington, and Rockland Rotoveyer.