| 摘要 |
A pulling head adapted for use with a crystal growing furnace and a crystal growing furnace containing such pulling head, which furnace comprises a high and low speed seed lift motor, a seed rotation motor, a rotatable platform about the upper portion of the furnace, a winch mounted on the platform and adapted for rotation about its own axis to maintain a cable on a central vertical axis, a cable about the winch, one end of the cable adapted to hold a seed crystal within a sealed vacuum or inert atmosphere of the furnace and a multiple-stage planetary gear differential mechanism to receive the output motions of both seed lift motors and the seed rotation motor and to provide a first seed rotation motion output to rotate the platform and a second output to rotate the winch, the second output being the weighted sum of the input motion of the speed ranges of the seed lift motors to provide a seed lift motion which is independent of the speed rotation motor, thereby providing a pulling head which combines the input motions of the seed lift and rotation motors and resolves them into at least two output motions and which permits the seed lift motors to be placed in a stationary condition and spaced apart from the rotatable platform. |
