Patent ID: 6834757
Filing Date: 2004-12-28
Classification: B64D,B65G

Abstract:
A roller drive unit for conveying an object comprising:a drive motor, a planetary gear with an input connected to the drive motor and with a first gear output and a second gear output; a drive roller, which is connected to the first gear output, to propel the object; a lifting apparatus connected to the second gear output, to lift the drive roller out of a retracted resting position, in which the drive roller does not contact the object, into a raised operating position in which the drive roller can engage the object; a first electrically controllable brake to slow down the drive roller to cause the lifting apparatus to lift the drive roller out of the retracted position into the raised position and to be completely opened during propelling of the object without slowing down the drive motor; and a second electrically controllable brake to hold the lifting apparatus in the raised position.