Abstract: In dental x-ray apparatus a control is provided for driving the high voltage transformer in the tube head at a frequency far above power line frequency. The transformer is driven with an inverter. A precision d-c voltage regulator that operates in an "add-on" mode and thus only handles a portion of the output current controls the voltage supplied to the inverter. The d-c voltage regulator is supplied a voltage by a transformerless a-c/d-c converter whose output is proportional to the 60 Hz power line voltage that supplies it. The x-ray tube filament transformer is also driven at a frequency above power line frequency. Means are provided to cut off power to the x-ray tube if its current does not reach a certain value within a short time after an exposure is initiated. Means are provided for isolating high voltage power circuits from low voltage control circuits.

Abstract: A safety coupling for an X-ray table tilt drive. An auxiliary coupling means in parallel with the main mechanical drive coupling has a substantially constant amount of free play over the entire operational tilt range of the table so that it ordinarily carries none of the drive force. In the event of mechanical failure of the main drive coupling the free play is taken up and the auxiliary coupling prevents the table from abruptly falling to the rest position.

Abstract: A tray for receiving, positioning and holding variously sized x-ray film cassettes in a substantially fixed position has substantially fixed dimensions and no adjustable parts. The tray includes a plurality of tiers, each tier having a fixed side support wall and a fixed base support ledge. The walls and ledges define corner blocks which cooperate with the edges of a film cassette to prevent both vertical and horizontal movement of the cassette.

Abstract: An automatic chest X-ray machine has a tray of unexposed rectangular cut film in a film-supply magazine enclosed in a light-tight housing supported in an inclined position approximtely 30.degree. from the vertical. A plunger pushes the lower portion of the tray forwardly toward a pair of vacuum suction cups which lift the top sheet of film and pull it forwardly and then upwardly forcing the upper edge of the lifted sheet of film against the upper edge of the tray and causing the sheet of film to bow outwardly. The vacuum cups then release their hold on the film and the resilience of the bowed sheet of film causes it to straighten out and drop down vertically into an open-clamp holder at the front of the machine at the exposure station.

Abstract: A tube for irradiation equipment for limiting an emergent beam, with a baseplate, possessing a central aperture, intended for attaching to the equipment, as well as four carrier plates, each of which possesses a limiting edge and a sliding edge located at right angles thereto. The carrier plates are located parallel to the baseplate, the limiting edge of each carrier plate resting against the sliding edge of the adjacent carrier plate and each of the two mutually opposite pairs of carrier plates being displaceable, parallel to the direction of its sliding edges and symmetrically to the center of the transmission aperture, for the purpose of continuously varying the transmission aperture defined by the limiting edges, during which displacement each of the displaced carrier plates carries with it the carrier plate, resting against the limiting edge of the former plate, parallel to the direction of the limiting edge of the latter plate.

Abstract: Chair apparatus specially adapted for detachable mounting on a tiltable tomography table to restrain and support a patient and his head for tomographic exposures during pneumoencephalography. The chair apparatus positions the patient's head close to the tomography table and permits multiaxial rotation of the patient about his head so that a defined isocenter in the patient's brain does not move with respect to the table. Two axes of rotation intersect the geometric center of tomographic study.

Abstract: A tomographic image of a selected layer of a stationary object is made by moving the source of X-rays along a first path at one side of the selected layer and by moving an ionography imaging chamber which contains a dielectric receptor sheet along a second path at the other side of the selected layer. The movement of the sheet is synchronized with movement of the source of X-rays and includes a translatory movement in a direction counter to the direction of movement of the source, a pivotal movement to maintain the sheet in a plane which is normal to the central beam of the bundle of X-rays, and a sidewise movement to vary the distance between the selected layer and the sheet so that the length of the projection of selected layer upon the sheet remains unchanged. If the sheet is rectangular, the pivotal movement is performed about an axis which is located in the plane of the selected layer and is parallel to the shorter sides of the sheet.

Abstract: A motorized device for rotating i.e. tilting the X-ray tube assembly in a linear and/or complex tomography radiographic system comprising the combination of a permanent magnet stepper motor coupled to a rotatable X-ray tube assembly through a helicon gear set and a spur gear set. The X-ray tube assembly incrementally rotates one angular step with each input drive pulse applied to the stepper motor from a pulse generator operated in accordance with a control input applied from an electronic control system in response to sensed positional change of the X-ray tube assembly. The stepper motor when unenergized is nevertheless adapted to provide a holding torque capability which eliminates the need for a separate brake assembly.

Abstract: A patient support stretcher for X-ray units is formed by curing a multiple layered composite in situ on a balsa wood core.

Abstract: An infant cradle or basket has upright basket ends and removable patient-support center panels of different lengths on which the infant is strapped and supported for X-ray examination. Beyond one of the basket ends is a motor or handcrank drive having a trunnion or pivot shaft on which the one basket end is mounted. Beyond the other basket end is a bearing support for a trunnion or pivot shaft. The basket is rotatable on its pivot shafts through 360.degree.. Three different interchangeable mounting means are provided so that the rotatable infant basket may be attached either to a separately rotatable adult patient X-ray examination basket, or to an inclinable X-ray examination table top, or to a stationary X-ray examination table top.