Patent ID: 8308868

Claim:
A method of collecting waste material from a field having artificial grass and particulate infill material; the method comprising: a) providing a field cleaning device comprising: i) a brush assembly comprising a rotatable brush; ii) a container having a bottom and at least one side wall, wherein said container is positioned to receive material that is picked up by the brush when the brush rotates, and further wherein said container includes openings in its bottom, said openings being sized and positioned to allow infill material to pass therethrough while retaining waste material; and iii) a vibrator for causing said container to vibrate to promote separation of particulate infill material from waste; b) moving said field cleaning device over a field in a manner effective to cause the brush to rotate to move waste and infill material from the field surface to the container; and c) causing the vibrator to vibrate the container to facilitate passage of infill material therethrough while retaining waste material and wherein: the field cleaning device includes at least one wheel connected to said brush assembly such that rotation of the wheel causes the brush to rotate, wherein said brush assembly is a first brush assembly, and wherein said wheel is a first wheel; and further wherein the device includes a second brush assembly; and further wherein the device includes a second wheel, wherein said second wheel is connected to said second brush assembly such that rotation of the second wheel causes the second brush to rotate; and further wherein said “moving said field cleaning device” comprises rotating said second wheel at rate different than the rate of rotation of said first wheel such that the second brush rotates at a speed different than the speed of rotation of the first brush.