Patent ID: 8733554

Claim:
An abrasive grains classifying apparatus, for classifying abrasive grains based on sizes of the abrasive grains, each of the abrasive grains having polyhedral shape in which mutually opposed surfaces are parallel to each other, the size of the each of the abrasive grains being determined by distances between said mutually opposed surfaces, the apparatus comprising: a first gap portion including two first rigid bodies disposed at a first predetermined distance from each other to supply the abrasive grains between the two first rigid bodies and classify the abrasive grains into first abrasive grains capable of passing between the two first rigid bodies and second abrasive grains incapable of passing between the two first rigid bodies; and a second gap portion including two second rigid bodies disposed at a second predetermined distance smaller than said first predetermined distance from each other to supply said first abrasive grains having passed through said first gap portion between the two second rigid bodies and classify said first abrasive grains into third abrasive grains capable of passing between the two second rigid bodies and fourth abrasive grains incapable of passing between the two second rigid bodies, wherein the two first rigid bodies comprise first rollers rotated by a first actuator and the two second rigid bodies comprise second rollers rotated by a second actuator, the first rollers and the second rollers are rotated by the first actuator and the second actuator independently from each other, the apparatus further comprises a first drive gear disposed between the first actuator and one roller of the first rollers and a first driven gear on the other roller of the first rollers engaged with the first drive gear, the other roller of the first rollers is rotated by the first actuator through the first drive gear and the first driven gear, the apparatus further comprises a second drive gear disposed between the second actuator and one roller of the second rollers and a second driven gear on the other roller of the second rollers engaged with the second drive gear, the other roller of the second rollers is rotated by the second actuator through the second drive gear and the second driven gear, and the first rollers and the second rollers are independently rotated by the first and second actuator in a direction to raise the abrasive grains.