Drive system for test sample positioning system

A drive mechanism for moving a sample holder horizontally from one place to another within a machine, comprising:

• a base pan for supporting said sample holder;
• a shaft positioned adjacent to said base pan and oriented horizontally, said shaft comprises a first end and a second end;
• a paddle slideably mounted to said shaft, said paddle engaging said sample holder;
• a first motor assembly for slideably moving said paddle relative to said shaft, said motor assembly comprising a drive motor located adjacent to said first end of said shaft, an endless belt driven by said drive motor and operatively connected to said paddle so as to enable said paddle to be moved relative to said shaft when said belt is driven by said motor, and a pulley located adjacent to said second end of said shaft, said belt extending from said drive motor to said pulley;
• and
• a second motor assembly comprising means for rotating said shaft relative to said base pan so as to permit said paddle to rotate with said shaft between an engagement position with respect to said sample holder and a disengagement position with respect to said sample holder, thereby permitting said paddle to selectively engage said sample holder;
• whereby said paddle moves said sample holder across said base pan when said second motor assembly has rotated said paddle into said engagement position and said drive motor moves said endless belt and paddle relative to said shaft.