US2790911A - Control for X-ray apparatus - Google Patents

Description

April 0, 1957 r E. B. GRAVES 2,790,911

CONTROL FOR X-RAY APPARATUS Filed March 16, 1954 1 2 .2

m sum-um Ii Q 3 Ma awi 1 I Q -2 BY a zlwwww United States Patent 2,790,911 CONTROL FOR X-RAY APPARATUS Edward B. Graves, South Euclid, Ohio, assignor to Picker X-Ray Corporation, Waite Mfg. Div., Inc'., Cleveland, Ohio, a corporation of Ohio Application March 16, 1954, Serial No. 416,487

2 Claims. (Cl. 250-93) This invention relates generally to the control of X-ray apparatus and more particularly to an arrangement for selectively enabling the independent operation of radiographic and fluoroscopic controls from a common control monitor.

In an X-ray apparatus it is usual to provide independent controls for the operating voltage, current, and time of X-ray tube operation so that when used for radiography the tube may be operated under several major conditions of operation and when used for fiuoroscopy the apparatus may be operated under a single condition of operation that may be adjusted over a limited range. Thus, the radiographic selector and the fluoroscopic adjuster are intended for operation independent of each other and are normally represented by independent operating members on a control panel. Conversion of the X-ray apparatus for operation in radiography or fluoroscopy, therefore, requires an operator to properly select the corresponding operating member and imposes a burden of possible delay and error in shifting from one to the other.

Accordingly, it is a principal object of this invention to combine the radiographic and fluoroscopic controls into a unitary monitor control which automatically insures independent operation of the controls in a selective manner.

Another object of this invention relates to the provision of a unitary monitor for controlling the operation of radiographic and fluoroscopic controls by automatically disabling one while the other is active to insure in-' dependent operation in accordance with a selected operating condition.

A further and general object of this invention relates to simplification of the procedural technique to enable efiicient operation of an X-ray apparatus in an optimum manner and with a minimum possibility of error.

Briefly, this invention contemplates the independent operation in an X-ray apparatus of radiographic and fluoroscopic controls in a selective manner which will insure that the proper control is active for a selected condition of operation. This is accomplished by combining the controls for operation from a common moni tor which automatically disables one control when the other is active to provide the correct control environment for a given operating condition.

In the drawings:

Fig. 1 illustrates an X-ray tube energizing circuit to which the invention is applied; and

Figs. 2 and 3 illustrate respectively side and face views of a unitary monitor control for the energizing circuit.

Referring now to Fig. l of the drawings, the energizing circuit for the X-ray tube is shown in detail as including an input autotransforrner 12 adapted to be connected to a source of supply energy and having its winding adjustably connected through a rotary contact switch 13 to the primary winding of a high potential transformer 15 which is divided in two primary sections P1 and P2. The

2,790,911 Patented Apr. 30, 1957 ice primary section P1 is adapted to apply a voltage through a corresponding secondary S1 having one end coupled to the anode 11 of the X-ray tube and theother end coupled to the metered output of a conventional current stabilizer which is shown diagrammatically in block form at 18 and may be of the type disclosed in United States Letters Patent No. 2,627,035 issued on January 27, 1953 to lack Ball. The other primary section P2 is magnetically coupled to a divided secondary comprising the secondary windings S2 and S3. The second ary S2 applies a potential directly across the filament 14 of the X-ray tube and has one side connected to one side of the secondary S3 whose other side is also coupled to the stabilizing control potential at the output of the current stabilizer. One end of the primary section P2 is connected to the input side of the current stabilizer to provide a controlled input voltage through adjustment of the step-resistance network R1 or rheostat R2. The energizing circuit also includes a volt meter 16 and a current meter 17 as well as other switches and resistances which are intended to operate in a manner to be hereinafter more fully described.

As hereinbefore indicated, rather widely differing conditions of operation are applied during radiographic examinations while, usually, a single major condition of operation prevails during fluoroscopic examinations with only a fine adjustment available to the operator. Thus, the contact arm 20 of the current limiting rheostat R2, which normally is adjustable over a limited range during fluoroscopic examination, may be selectively positioned in contact with contacts 1 or 2 to introduce two other major filament current conditions of operation during radiographic examinations. Accordingly, the current meter 17 must be calibrated for the diiferent conditions of operation and the selector switch C is provided to recalibrate the current meter by introducing various values of resistance into the meter circuit corresponding to the different conditions of operation. Similarly, it is desirable to recalibrate the volt meter 16 for each different condition of operation, and the rotary selector switch A is provided to change the volt meter calibration.

Normally, during fluoroscopic examination, there is no critical timing necessary to control the tube operation. During radiographic operations, on the other hand, it is necessary to control the duration of tube operation in accordance with the type of film exposure desired and, for this reason, an additional selector switch B is provided in the energizing circuit between the supply line and a primary switch operating relay 25. Thus, when the switch B is in the fluoroscopic contact position at F, it introduces a foot switch 26 into the circuit which may be controlled at will to energize the relay 2S and apply or remove voltage at the X-ray tube. On the other hand, when the switch B is positioned to the common contacts 1 and 2, it introduces a timer T into the circuit which will maintain the relay 25 energized for only a predetermined period of time corresponding to the desired film exposure.

It is apparent from the foregoing description of the function and operation of each of the switches in the X-ray tube energizing circuit that the selector switches A, B and C are intended to remain stationary in the fluoroscopic position while the rheostat contact arm 20 is able to move through a limited range of relatively fine current adjustment.

It is also apparent that when the apparatus is to be conditioned for radiographic examination, the rheostat contact arm 20 is positioned off of the rheostat and into contact with the switch contacts 1 or 2 to provide the selected filament current corresponding to the particular condition of radiographic operation. In like menner, each of the calibrating switches A and C must be positioned to contact positions 1 or 2 corresponding to the position of the rheostat contact arm 20 in order that the changed loading in each case will be properly reflected through recalibrated meters in the energizing circuit. At the same time that the rheostat switch arm 20 and recalibrating switches A and C are positioned into the corresponding radiographic positions, the switch B must be positioned from its fluoroscopic position to a contact position at 1 or 2 which will introduce the timer T into the relay control circuit in order that the proper timing relationship may be introduced into the X-ray tube energizing circuit.

As best shown schematically in Fig. 1 of the drawings, each of the control switches A, B and C have been ganged for operation with each other and with the rheostat contact arm 20 for simultaneous movement between the contact positions F, 1 and 2. However, it is desired that the ganged relationship between the rheostat contact arm 20 and the switches A, B and C be disengaged or otherwise disabled when the rheostat switch arm 20 and the other switches are positioned in the fluoroscopic contact position F, after which time only the rheostat contact arm 20 moves to vary the amount of resistance introduced into the filament circuit.

In the preferred form illustrated in Figs. 2 and 3 of the drawings, this is accomplished by mounting concentric with the rheostat contact arm 20 an additional lever 30 which moves in the same direction and in unison with the contact arm 20 as the knob 31 is rotated. The switches A, B and C are mounted in a housing 32 and are ganged for simultaneous movement in the same direction by a pivoted switch arm 33 which has a bifurcated extremity that engages the lever 30 for movement thereby. In the form shown the switch arm 33 is preferably of the conventional snap-action, toggle type to insure positive positioning of the switches as the lever 30 is moved. The arrangement is such that when the rheostat contact arm 20 is adjusted over the limited rheostat range, all of the switches A, B and C remain stationary in the fluoroscopic contact position F. On the other hand, as the rheostat contact arm 20 is rotated out of contact with the rheostat towards the contact positions 1 and 2, the additional lever arm 30 engages the common switch arm 33 to position each of the three switches A, B and C into the first and second contact positions. As shown in the drawings, the engagement between the lever and switch arms in accomplished at the extreme counter-clockwise point of rotation of the rheostat contact arm 20 so that the operator, in changing from fluoroscopic operation to radiographic, would merely return the filament current control rheostat R2 to its extreme low position and thereby cause the equipment to change over to one or more of the selected radiographic filament current conditions of operation.

Thus, there has been provided an X-ray tube energizing circuit having independently operated control facilities, some of which are intended to be operative only during fluoroscopic operation of the apparatus and others of which are intended to be operative only during radiographic operation of the apparatus along with an arrangement for combining the operation of each of the control facilities from a common monitor control which insures independent operation of the respective control facilities in accordance with the desired type of X-ray operation.

I claim:

1. In an X-ray tube energizing circuit having means for applying a variable high potential across an X-ray tube, a first switch means adapted in one position to apply said means directly to the tube for fluoroscopic operation and in another position to apply said means during a predetermined interval of time for radiographic operation, a first meter means for measuring the applied potential, a second switch means for selectively calibrating said first meter means in accordance with the applied potential, a second meter means for measuring the tube discharge current, a third switch means for selectively calibrating said second meter means, means for stabilizing the tube discharge current, a controlled input for said stabilizing means including a variable impedance, said impedance having a portion variable in small increments and another portion variable in relatively large increments, a fourth switch means for selectively varying said variable impedance over its entire range, a switch operating member, means coupling each of said switch means for unitary movement by said operating member for radiographic operation of the tube, and means for disabling said first, second and third switch means from movement by said operating member as said fourth switch means is positioned from the large increment portion to the small increment portion of said variable impedance to permit fine adjustment of only the stabilizing input during fluoroscopic operation of the tube.

2. The X-ray tube energizing circuit of claim 1 wherein each of said switch means includes a movable switch arm adapted for movement into contact with a plurality of switch contacts, and wherein each of said movable switch arms is ganged together through a disabling connection with said operating member, and wherein said fourth switch means includes a movable contact arm for maintaining contact with one portion of said variable impedance to provide the small incremental adjustment and wherein another portion of said variable impedance has physically spaced contacts adapted to be contacted by .the corresponding switch arm to provide the relatively large incremental adjustment.

References Cited in the file of this patent UNITED STATES PATENTS 1,920,656 Morrison Aug. 1, 1933 1,946,176 Mutscheller Feb. 6, 1934 1,961,705 Mutscheller June 5, 1934 2,186,154 Stoekle Jan. 9, 1940 2,244,137 Bischofi et al. June 3, 1941 2,350,277 Grimes May 30, 1944 2,477,298 Goldfield July 26, 1949

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