Patent ID: 6626057
Filing Date: 2003-09-30
Classification: F16H,Y10T

Abstract:
A speed-changing gear set inside a drive system of a scanner wherein the drive system further includes a drive motor and an output unit, and the speed-changing gear set comprises:a control motor; a cam having a gear section and a curve surface section, wherein the gear section engages with a gear on the driving motor, and the curve surface section has a first position and a second position; a first gear on the same axle holding the cam, wherein the first gear couples with the output unit; a second gear coupled to the cam so that the second gear tracks the movement of the cam; a third gear mounted on the second gear having the same axle as the second gear so that the second and the third gear rotate synchronously, and the third gear engages with the first gear; an axle crossing over the curve surface section of the cam, wherein an elastic device pushes the axle against the cam surface in a direction toward the cam center so that the axle is able to slide along the curve surface of the cam when the cam moves; a fourth gear and a fifth gear joined together and mounted on the axle so that the fourth and the fifth gear move in synchrony; and a first stopping block and a second stopping block for limiting the moving range of the cam, wherein if the cam is driven by the control motor to stop at the first stopping block position, the axle touches the first position on the curve surface of the cam, the second gear meshes with the gear on the driving motor, and the output unit is driven by the driving motor through the gear train that includes the second gear, the third gear and the first gear; and if the cam is driven by the control motor to stop at the second stopping block position, the axle touches the second position on the curve surface of the cam, the fifth gear meshes with the gear on the driving motor and the fourth gear meshes with the second gear, and the output unit is now driven by the driving motor through the gear train that includes the fifth gear, the fourth gear, the second gear, the third gear and the first gear.