X-RAY SPOT FILM DEVICE

摘要

15-XR-1529 In a spot film device, the inner and main carriages for a film cassette are positioned with reversible servo motors. An x-ray grid is mounted on the bottom of the main carriage and a cross grid is mounted on tracks beneath the carriage such that the cross grid may be used or not used for fluoroscopy and both grids may be used for radiography. Field defining masks are also mounted for translating selectively with the carriage. Individual reversible servo motor drives are used to advance and retract the masks and cross grid. Springs that can stretch slightly are provided for absorbing shock or negating drive system momentum when the masks or grid are stopped abruptly. Reduced power is applied to the mask and grid drive motors when the marks and grid reach their stops for holding them against their stops. An independently movable palpator cone uses a reversible servo motor. A latch for holding the palpator cone in position is self-locking, but is automatically releasable in response to the servo motor being commanded to reverse direction. Cassettes can be loaded or unloaded from either the front or the rear of the spot film device.