| 摘要 |
A panoramic tomography X-ray apparatus comprises a fixed frame to which another rotary frame is suspended, the rotary frame having an X-ray tube at one end thereof and a film cartridge device for X-ray film at an opposite end thereof. Drive mechanism for turning the rotary frame in a substantially horizontal plane is provided, for taking a panoramic X-ray photograph. The drive mechanism comprise a drive and guide groove which has straight side sections and a curved section connecting the side sections together and a drive unit also comprising a drive wheel which, when rotated by the drive unit, turns the rotary frame. The rotary frame is suspended from the fixed frame by a crank mechanism which is joined to both the rotary frame and to the fixed frame through respective sets of bearings. The drive and guide mechanism along with the crank mechanism interact in such a manner that, in the front area of a dental arch, i.e. when the corresponding curved section of the guide and drive groove is in operation, the rotary frame turns around one axis of the crank mechanism, while in the side areas, when guided by the straight sections of the drive and guide groove, the rotary frame simultaneously turns about two axes of the crank mechanism.
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