| 摘要 |
Tray lift 3 comprises elevator screws 4, comprising shaft 5 mounted for rotation and helical flange 7. Flange 7 defines a first length 8 with a first pitch, and second length 9 with a second, smaller pitch. There may be a third length 11 with a third pitch greater than the second pitch. Trays 1 engaged by the flange in the first section are un-nested, whilst trays in the middle section are nested to save space. If the third length 11 is present, the trays 1 will be un-nested when they reach the top of the tray lift. Screws 4 arranged on opposite sides of tray 1 may rotate in opposing directions, and screws 4 arranged on the same side of tray 1 may also rotate in opposing directions. Lift 3 may comprise sensors to detect the arrival of a tray 1 between screws 4, or to detect the presence of a tray 1 in lift 3. An actuator may be arranged to discharge a tray 1 from lift 3, and a controller may control the rotation of screws 4 is response to a signal from one or more sensors. Tray lift 3 may be used for trays that are used with X-ray scanning apparatus in security checks, for example in airports. |
