Patent ID: 8172650
Filing Date: 2012-05-08
Classification: B24B,B25F

Abstract:
1. An automatic-shift dual-action tool providing smooth and uninterrupted switching between axial actions without turning off and without any mechanical manipulation by a user, comprising: a shaft balancer, including a rotatable shaft, an upper lobe and a lower lobe that are partly stacked where the shaft is located to provide balance, and a drive head plate at a bottom surface of the shaft balancer; a spindle assembly which is eccentrically connected with the shaft balancer and includes a spindle rotatably affixed to the shaft; a clutch plate and a pressure plate that are rotatably and concentrically coupled on the spindle in sequence; and a backup pad rotatably and detachably connected with the spindle assembly through a threaded stud formed on a top surface thereof; wherein when the automatic-shift dual-action tool operates at a high velocity, the pressure plate is rotated upwards to drive the clutch plate to engage with the drive head plate via centrifugal force so that the backup pad is rotated in unison with the spindle and the shaft of the shaft balancer to perform rotary grinding operation; and wherein when the automatic-shift dual-action tool operates at a low velocity, the pressure plate releases pressure on the clutch plate to disengage the pressure plate and the clutch plate from the spindle so that the backup pad is rotated in unison with the spindle and the shaft of the shaft balancer to perform random orbital sanding operation.