US1950531A - Circuit for X-ray multiple tube stands - Google Patents

Description

March 13, 1934- J. B. WANTZ CIRCUIT FOR X-RAY MULTIPLE TUBE STANDS Filed Feb 21 a PE V\ V E H n E 0 W T T B A 5 Mu U NJ E V v m B Patented Mar. 13, 1934 UNITED STATES FATE QFFECE CIRCUIT FOR X-RAY MULTIPLE TUBE STANDS Application February 21, 1927, Serial No. 169,734

2 Claims.

The present invention has to do with electrical circuits and relates particularly to a circuit adapted to be used in conjunction with the multiple X-ray tube stand or tube holder, for which application for patent has been made in the name of Julius B. Wantz, and Julius J. Grobe, under date of December 3, 1926, Serial No. 152,347.

Radiography has made tremendous strides within the last two or three years. The improvements in tube structure and performance have resulted in finer X-ray photographs than have ever heretofore been made, and the improvements in X-ray apparatus have made it possible to obtain radiographs without guess-work.

Until relatively recently, however, photographs by X-light were made without any certainty as to whether the part desired to be shown in the radiograph was actually being photographed.

With the combination of fluoroscopic screens with the various X-ray apparatus used for photography, and when means for quick change from fluoroscopy to radiography were installed, the ability of an operator to obtain a satisfactory radiograph was many times multiplied.

One of the principal obstacles which has been met in combining fluoroscopic screens and radiographic outfits, however, has been that the two voltages required, the one for radiography and the other for fluoroscopy, are so entirely different that it is difficult with the ordinary commercial X-ray apparatus to successfully obtain the benefit of a prior or previous fluoroscopic examina tion for disclosing the proper object position for a radiograph.

Almost invariably, when the ordinary type of X-ray apparatus is employed, the patient to be photographed will move during the time adjustments are being made to change the character of the voltage from that for fluoroscopy to that for radiography. This unhappy condition was a factor in the invention of the multiple tube stand, and other apparatus, for the purpose of facilitating the rapid change of an X-ray apparatus from a setting for fluoroscopic work to a setting for radiographic work, or vice versa.

The energy dissipated when radiographs are being made is generally tremendous and much more than when fluoroscopic examinations are being conducted.

In order to satisfactorily change from a fluoroscopic voltage to a radiographic voltage, it is necessary in the hot cathode type of tube to change the voltage impressed across the elec trodes within the tube and to anteriorly or concurrently modify the electromotive force impressed upon the filament forming a part of the cathode of a tube. This is true whether one tube or two or more tubes are employed in a single apparatus.

Ordinarily, the voltage impressed upon the electrodes of a tube is controlled by an auto transformer. The adjustments in respect to such auto transformer are coarse, and may be somewhat quickly obtained by adjusting the control handle upon a conventional auto transformer, generally contained in a control stand.

But very accurate adjustment is necessary with respect to the filament of a tube.

An adjustment for the auto transformer for 7. the current impressed across the electrodes may be disturbed frequently because so readily reobtained. The adjustment for the filament, however, is difficult to obtain and once determined should seldom be varied. Further, an adjustment for fluoroscopic examinations or an adjustment for radiographic worl; once obtained should be maintained, if possible, because diihcult to obtain to an accurate degree and because of the time required to procure. Certainly, good practice and economy of time forbids frequent broad changes of the adjustment required to heat a filament for a fluoroscopic current to an adjustment required in conjunction with the high voltage impressed upon the electrodes of a tube for radiographic work.

The reason for this is the sensitivity of the filament which is so great that a very delicate control member or filament current regulator is generally employed in well assembled X-ray apparatus. A great number of turns of the control handle of a device is necessary in order to change it from the adjustment employed for radiography to that necessary for iluoroscopy, or vice versa.

The present invention concerns the circuit or circuits to the filament of a tube, and the objects of the invention are to provide a plurality of separahly maintainable adjustments for a filament current transformer so that in changing from fluoroscopy to radiography, rather than make a change in the adjustment of a single unit controlling the intensity of the electromotive force applied to the filament, an auxiliary filament current control means is brought into play and used in the second adjustments.

There are a number of ways which I have conceived in which circuits may be arranged for the provision of a multiple adjustment of filament current. The principle of the invention is having an electrode .pted to be the provision of control means for the filament having in combination therewith a second (or third, etc.) or auxiliary control means whereby a current of different intensity from that impressed upon the filament through the first control means may e impressed upon such filament and controlled by such second (or tiird, etc.) control means.

It is quite manifest that a circuit may be arranged with two step-down transformers instead of only one as shown. It is equally manifest that two filament current control means may be employed with a single transformer and obtain the same result when a single control means is used in conjunction with two transformers. Of course, two filament current control means and two filament current transformers may also be employed. Again, two filament controls may be used conjointly rather than inde pendently with one or more transformers.

The filament current control members may be arranged to operate in series or in parallel, as desired.

There is submitted with this application a single sheet of drawing schematically illustrating a circuit suitable for obtaining the objects herein described.

Said drawing includes two figures, Figure 1 showing schematically a circuit embodying the invention and a tube stand; and Figure 2 an enlarged view of the switch S of Figure 1, one position of the switch being shown in full lines and another in dotted lines.

In Figure 1, the tube stand is disclosed in plan view. Such stand includes a vertical column upon which a tube holder is disposed. The tube holder 11 is counterbalanced by a weight (not shown) adapted to reciprocate within the column 10, the cable 12 to such counterweight and a pulley 13, over which it passes, being shown at the top of the column 10.

The multiple tube holder 11 comprises a main carriage l4 swivelly disposed. at 15 upon a member 16 movable vertically upon the column 10 and it has side arms 17 terminating in a tie-rod 18. The side arms 17 provide tracks for a tube supporting board 19 upon which two (or more) tubes 20 are mounted, said board being supplied with roller bearings 21 at its opposite sides. The tube board 19, therefore, is adapted to be moved intermediate the main carriage l4.- and tie-rod 18 along the side arms 17.

The switch S disclosed in the drawing is adapted to be actuated by the movements of the tube board 19, so that when one of the tubes 20 thereon is in operable position, the switch S in one extreme position, but when the other tube 20 is in operable position, the switch. S is oppositely disposed.

At the right hand side of the drawing, one of the high tension conduits 22 is shown, and as will be hereinafter pointed out, the other high tension conduit may be also employed as a filament current conduit. The other high tension line marked 26 connected to the cathode and one side of the secondary circuit of the filament may be employed for such purpose.

Wherever, hereinbeiore or hereinafter heated cathode tn e or h t cathode X-ray or a similar expression is employed,

X-ray tube a electr'cally energized i'or purpose contrxling the passage of high tension intermediate the two main electrodes of a tube is intended. Such an electrode is sometimes referred to herein as an electron emitting electrode.

Shields are adapted to be used about the tubes 20 as is now common in the art, such shields being opaque to X-ray light and having the general contour of the tube 20 about which they are disposed except for the window to allow the passage of X-ray light.

Reference should be had to the application referred to above for an illustration of a multiple tube holder in a table and in a steresoopic device. Such devices have a rotating or sliding tube holder in which the invention may be utilized as well as in the tube stand here illustrated.

Generally, from a single source of current, there is adapted to be delivered at a terminal or terminals adjacent to a sliding or movable tube rack for a plurality of tubes (two as here shown), electromotive force of different magnitudes. The invention may readily be adapted to meet the requirements of other X-ray apparatus, as is apparent. The electromotive force so delivered is for controlling the X-ray radiation.

In the multiple tube holders here disclosed and as shown in said prior application, the X-ray tubes are adapted to be moved into position for use one at a time and shifted as necessity requires.

Suitable contacts are generally provided in association with the sliding or rotatable tube carrier as the case may be so that each tube, as it moves into position, automatically establishes electrical connection with the circuit to the filament of the X-ray tube in operable position. The ci 'cuit here described may be substituted for the filament current set out in the prior application referred to.

Means are provided by a multiple position switch, or in some other manner, whereby, as an incident to the movement of one tube, or of the tube rack or holder, here a sliding movement, the circuit to the filament terminal is broken and the circuit is reestablished at the time a second tube (or the same tube again) is moved into position in the stand for use.

The conduits from the alternating current source are indicated 1 and 2. Line 1 runs directly to one terminal of the primary of the filament current transformer, so marked in the drawing. Line 2 runs to a multiple position switch marked S. The other terminals of said switch are connected to conduits running to the filament current control members 3 and 4.

From the filament current control members 3 and 4 separate conduits are run to the opposite terminal of the primary of said filament current transformer. The secondary of the said filament current transformer is directly connected to the contacts on the movable tube holder as each tube is brought into a proper position for use.

By the use of the switch S which is adapted to be automatically actuated as an incident to the movement of the multiple tube holder, contacts are made and broken in the proper order to provide suitable filament current for the tube or tubes attached to the multiple holder and about to have igh tension impressed thereon.

In one position of the multiple tube holder, current passes through the filament control means 3 while in another position current passes through the filament control member 4. These two are of different character whereby a different potential is delivered through the contacts upon the stand engaging the contacts upon the movable tube holder.

Fill

Ordinarily one of the members 3 or 4 is adjusted for fluoroscopic work and the other for radiographic work. Of course, more than two tubes and two adjustments may be provided.

The high potential conduits to the tube 20 are adapted to be connected to the electrodes of the tubes upon the tube carrier one at a time by the contacts shown. The latter conduits are connected as an incident to actuation of switch S. Buttons 23 at the end of the anode of the X-ray tubes 20 are adapted to come in contact with the spring actuated button 24 forming the terminal of the high tension current conduit 22 shown at the right of Figure 1 in the drawing.

Of course, the filament lead 1 may be used as a conduit for high tension and the apparatus accordingly readjusted.

Movement of the tube carrier 19, therefore, brings into play, first, the proper filament cur rent and adjustment for the impression of the proper high potential by another switch means, and, secondly, adaptability to receive high tension electromotive force.

Instead of the movement of the multiple tube holder directly actuating the filament current switch, or the filament current control or regulatory member, the movement thereof may provide a safety device, permitting of the establishment of certain predetermined contacts, the actual contacting being accomplished manually or by means other than the movement of the multiple tube holder 19.

When the invention is used in connection with a stereoscopic shift, the contacts in the switch S as Well as the plunger contacts for both high tension and filament current are likewise adapted to be shifted with the stereoscopic shift.

What I claim is new and desire to procure by Letters Patent of the United States is:

1. A holder for a plurality of X-ray tubes shiftable to bring such tubes into operable position one at a time, in combination with means for impressing an electromotive force of a selected magnitude upon the X-ray tube positioned for operation, said means for impressing such electromotive force upon the selected tube comprising a switch having a plurality of contacts and a shiftable connector for the selective engagement of said contacts, in combination with a plurality of circuits each or" which is energized to a predetermined magnitude and includes certain of said contacts, and means controlled by the position of said holder and the movement thereof for determining the engagement of said connector with said contacts.

2. A holder for a plurality of X-ray tubes, said holder being shiftable to bring such tubes into operable position one at a time, in combination with means for impressing an electromotive force of a selected magnitude upon the X-ray to be operated, said means for impressing such force upon a tube comprising a plurality of circuits each energized to a diiferent magnitude, each of said circuits having a contact therein, and a switch member having a connecting member actuated by movement of said holder to engage one of said contacts to include the tube selected for operation in the circuit in which such contact is disposed, the relative position of said connecting member and of said contacts causing the former to engage the latter concurrently with the movement of said holder to bring the selected tube into operable position.

JULIUS B. WANTZ.

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