US2493161A - X-ray apparatus - Google Patents

Description

Jan. 3, 1950 NEMET 14mm APPARATUS 2 Sheets-Sheet 1 Filed July 13,-:1945

ANTHONYNEMEZ INVENTOR.

ATTORNEY Jan.3, 1950 I ANEMET 2,493,161

X-RAY APPARATUS Filed July 15 1945 2 Sheets-Sheet 2 ANTHONY NEMEZ I N V EN TOR.

AT TOR/1E1? be suitable for both purposes.

Patented Jan. 3, 1950 X-RA Y APP-ARA EUS Anthony Nemet, London, England, assignorto The Hartford National Bank & Trust Company, Hartford, Conn, as trustee Application July 13, 1945,; Serial No. 604,935 In Great Britain December 13, 1943 Section 1, Public Law 690, August 8, 1946 Patent. expires December 13, 1963 6.. Claims.

In X-rav a aratus of the type used r ma chest radio-graphy (miniature radio r phy in which the image formedon a fluorescent screen is photographed on afilm of the hind employed in cinematography, the distance between the focus of the X-ray tube and the screen is usually about 3 it. In ordinary chest radiography this distance (hereinafter. referred .to as. the. focal distance) varies between 4% and 6 it. It is. frequently required that X-ray apparatus should In this case i is necessary that either the tube or the screen stand should be mobile and readily adjustable to the correct focal distance. The cassette holder is usually attached to the front. of the screen uni When moving the tube or the screen to the alternative focal distance it is essential that the centre of the X-ray beam should remain directed accurately towards the centre of the screen or cassette. In known apparatus the movement is free and consequently l e-centering is necessary after every changeover from mass chest radiography to ordinary radiography, or vice versa.

According to the present invention the Xeray tube is secured to a holder carried by a movable support which is constrained to move in such manner that in two different positions corresponding to two desired focal distances, the X- ray beam is directedtowards the centre of the screen or cassette. Preferably the X-ray tube is secured to a holder constituting or rigidly associated with one side of a parallelogram linkage the opposite side of which is fixed, the parallelogram linkage being adapted to swing between two end positions in which it is arrested, the end positions being so selected that in each end position the X-ray tube is so disposed that the centre of the beam is directed towards the centre of the screen or cassette, whereas the spacing between the two end positions corresponds to a desired diiierence in the focal distance. In one convenient form of the invention, the X=ray tube is fixed in vertical position on a horizontal tube holder arm, which also carries a small lightprojector tube. This arm is supported on a main support (usually a casting) in such a way that it can swing round a horizontal axis. The main support is held on a horizontal spindle which is clamped to the top of the high tension generator. The main support can swing round this horizontal spindle, the axis of which remains stationary- The main support also carries an extension at its lower extremity which is coupled to one or several vertical piston orpistons. This piston is spring loadedin such a way that it is ke t in the middle position. by a set of; sprin s which are compressed in either extreme position. Thefhoria ntal tube holder casting is also. fixed onztoa s y-rod, the opposite end of which is pivoted in a bearin fixed on the top of. the high tension en rator. The top end of the stay-rod is also pivoted in the horizontal tube holding arm. the pivot pointbeing on the opp si e side of the ca tingto the. X-ray tube, the main supportin spindle being in the approximately central position. the horizontal tube holder, the main supb rt, the top. of the high tension generator, and the stay-rod iorm a parallelogram, which is Gamble of swinging to a' forward .or a back- Wardposition with respect to the-vertical. Asv a consequence the tube holder arm remains horirental and the tube remains vertical during the whole or its swing. The swing is limited by: stops in such a way that the centre or the Xeraybeam should remain at the same height in either extreme position. The spring-loaded piston men;-

'tioned above has the purpose of countereaoting derstanding of the invention being omitted.

Fig. 2 showsona somewhat smaller Scale. a perspective View in theopposite direction with the main support arm in the other end position.

Fig. 3 is a detail view of the spring buffer a1".-

- ranger-neat.

Fig. 4 is a-detail view .of the bracket which receives the 'X-ray tube.

Referring first to Figs. 1 to 3, the apparatus comprises a base I on which the high tension generator, .a'transformer unit 2. is mounted. u i 2 o eth r with th associated termnsists control panels (not is. nclosed by skir or musing 3 F g... .2) which as been mitted imm 1. in orderto s ow details which would ot erwise have b en; hidden. The t med? (Fla 2: s sec red on brac et 5 whi h-isdetach ably mou ed on horizontal tube holderarm .4. the axis of the tube 3.? being vertical. The-supply c nnectio s to he .X ra tube a e indicated tit-.33-

The bracket .5 is deta hably ss oported by e a m 4. The tube holder arm .4 is pivo ally supported at the upper end of the main support arm 1 by means of a spindle 6. The lower end of the arm I is pivotally mounted on top of the transformer unit 2 by means of a spindle 8 mounted in bearings 9 on the unit 2. The end of the arm 4 remote from the tube holder bracket 5 is pivotally attached at H to a tie-rod l which extends parallel to the main support arm 1. The lower end of the tie rod is pivotally mounted at l2 on a bracket member i rigid with the transformer unit 2. The pivot at I2 is level with the pivot formed by the spindle 8 and the distance between pivots 8 and I2 is equal to the distance between the spindle 8 and the pivot H on the arm 4. To enable the length of the tie-rod ill to be adjusted to correspond exactly to the length of the main support arm I, the tie-rod ID includes an adjustable link l3 which is secured in relation to the main tie rod by adjustable nuts one of which is shown at I4. In this way a precise parallelogram linkage is produced the upper link 4 of which is always horizontal whatever the inclination of the links "I and I0. Consequently the X-ray tube 32 is always vertical and the axis of the X-ray beam is always horizontal. The swinging main support arm 1 is so controlled that in its two end positions the tube holder arm 4 lies in the same horizontal plane, so that in these two positions the centre of the X-ray beam is directed towards the centre of a vertical cassette or screen occupying a fixed position. Fig. 2 shows the position for the shorter focal distance and Fig. 1 that for the longer focal distance.

The mechanism for controlling and limiting the movement of the main support arm I is shown in Figs. 1 and 3. At its lower end, the arm 1 is provided with two lugs i6 each of which is pivotally connected to a plunger II. This plunger I1 .is received in upper and lower guides I8, is which are rigidly united by tie rods 22 and are pivotally supported at 20 on a base bracket 2|. Between 'the upper guide I8 and the lower guide IS the plunger I1 carries a spring 23 between an upper cap 24 and a lower cap 25. The caps 24, 25 are associated with the plunger i! in such manner freely through the cap 24 but carries the cap 25 along with it to compress the spring 23. Thus :the spring 23 serves as a buffer cushioning the weight of the moving system in both directions of .movement. To secure the main support arm I in its end positions, a latch member 28 is pivotally mounted at 30 on the upper guide 18 and is urged by a spring 23 towards the plunger I1 so that in the end positions it comes into engagement with locking grooves in the plunger. In Fig. 3 the look- -'ing groove 21 for securing the plunger I! in its lowermost position is visible, the other locking groove being hidden by the upper guide [8. To prevent excessive movement of the plunger I! in either direction it is provided with a stop ring 26 which is secured to it between the upper and lower guides l8, l9 and is adapted to be arrested by contact with the bases of the caps 24, 25 in the two directions of movement.

Corresponding to the swinging movement of the main support arm 1, the plungers I! will also swing about their pivots 20. Consequently, the skirt covering the buffer spring assemblies must have slots or elongated holes for the passage of the plungers H. To mask these holes in the completely assembled apparatus, the upper guides l8 carry masking plates 31.

In the construction shown, two buffer spring assemblies are provided and one only is equipped with the locking mechanism 21, 28, 29, 30. It

will be apparent that any desired number of buffer spring assemblies could be provided and that any or all could be equipped with a locking mechanism.

As seen from the detail view of Fig. 4, the tube holder bracket 5 to which the X-ray tube (32, Fig. 2) is fastened and whereby the tube is mounted on the tube holder arm (4, Figs. 1 and 2), may be provided with a light projector tube 35 adapted to project a narrow beam of light which is substantially (although not precisely) coincident with the axis of the X-ray beam so that the alignment of the X-ray beam with the centre of the screen or cassette in the two end positions of the main support arm (1, Figs. 1 and 2) can be verified visually by means of the light beam. In the construction shown, the projector tube 35 is wholly accommodated within the bracket 5, the front end of the tube being supported in the hole through which the light passes and the rear end being supported by an internal lug 36 on the bracket 5. Current is supplied to the lamp in the projector tube 36 by leads 31.

Instead of being disposed within the bracket 5, the light projector may be arranged outside the bracket, extending forwardly from the front face thereof to which it is secured.

It will be apparent, that if an X-ray beam of constant angle is employed, the effective area at the cassette or screen will be greater at a greater focal distance than at the lesser focal distance. Consequently it is preferred to provide an adjustable diaphragm for limiting the beam and to adjust this diaphragm automatically in accordance with the movement of the tube towards and away from the screen in the manner more fully described and claimed in my co-pending application for U. S. Patent, Serial No. 604,936, filed July 13. 1945. The diaphragm may be of the iris-type or of the interchangeable apertured plate type and the control is readily derived by Bowden wire from the moving elements of the parallelogram linkage.

I claim:

1. X-ray apparatus comprising an X-ray tube for use with both a screen and a film cassette, a holder for the tube, and a support for said holder movable to either of two difierent coaxial positions at two desired focal distances from the plane of the cassette, the movement of said holder and said support being such that in both of said positions the beam from the tube is aligned with the center of the cassette.

2. X-ray apparatus adapted for ordinary and miniature radiography comprising an X-ray tube for use with both a screen and a film cassette, a supporting base, a main supporting arm adapted to pivot about a horizontal spindle on the top of said supporting base, a horizontal tube holder arm pivotally attached to said main supporting arm, and a stay-rod pivotally attached to said tube holder arm and to a fixed pivot mounted on the supporting base level with the horizontal spindle and so spaced therefrom that the stay-rod extends parallel to the main supporting arm whereby said X-ray tube is movable to either of two preselected coaxial positions at two different focal distances from the plane of the cassette and is aligned with the center of the cassette at either position.

3. X-ray apparatus adapted for ordinary and miniature radiography comprising an X-ray tube for use with both a screen and a film cassette, a supporting base, a main supporting arm adapted to pivot about a horizontal spindle on top of said supporting base, a plunger member pivotally secured to said main supporting arm, a buffer spring arrangement for limiting the movement of said plunger thereby limiting the movement of said main supporting arm about said spindle, a horizontal tube holder arm pivotally attached to said main supporting arm, and a stay-rod pivotally attached to said tube holder arm and to a fixed pivot mounted on the supporting base level with the horizontal spindle and S0 spaced therefrom that the stay-rod extends parallel to the main supporting arm whereby said X-ray tube is movable to either of two preselected coaxial positions at two different focal distances from the plane of the cassette and is aligned with the center of the cassette at either position.

4. X-ray apparatus adapted for ordinary and miniature radiography comprising an X-ray tube for use with both a screen and a film cassette, a supporting base, a main supporting arm adapted to pivot about a spindle on top of said supporting base, a plunger member pivotally secured to said main supporting arm, a buffer spring arrangement for limiting the movement of said plunger thereby limiting the movement of said main supporting arm about said spindle, a locking mechanism for arresting the movement of said supporting arm about said spindle in either of two positions, a horizontal tube holder arm pivotally attached to said main supporting arm, and a stay-rod pivotally attached to said tube holder arm and to a fixed pivot mounted on the supporting base level with the horizontal spindle and so spaced therefrom that the stay-rod extends parallel to the main supporting arm whereby said X-ray tube is movable to either of the two preselected coaxial positions at two different focal distances from the plane of the cassette and is aligned with the center of the cassette at either position.

5. X-ray apparatus adapted for ordinary and miniature radiography comprising an X-ray tube for use with both a screen and a film cassette, a supporting base, a main supporting arm adapted to pivot about a spindle on top of said supporting base, a plunger attached to a fixed pivot on said supporting base and secured to said main supporting arm, a spring carried by said plunger, cap members on either end of said spring member carried by said plunger, stop members arranged to limit the travel of said cap members in two opposite directions thereby compressing said spring when said plunger is moved to cushion the movement of said plunger and said main supporting arm, a horizontal tube holder arm pivotally attached to said main supporting arm, and a stayrod pivotally attached to said tube holder arm and to a fixed pivot mounted on the supporting base level with the horizontal spindle and so spaced therefrom that the stay-rod extends parallel to the main supporting arm whereby said tube is movable to either of two preselected coaxial positions at two different focal distances from the plane of the cassette and is aligned with the center of the cassette at either position.

6. X-ray apparatus for ordinary and miniature radiography comprising an X-ray tube for use with both a screen and a film cassette, a supporting base, a main supporting arm adapted to pivot about a spindle on top of said supporting base and secured to said main supporting arm, a spring carried by said plunger, cap members on either end of said spring member carried by said plunger, stop members arranged to limit the travel of said cap members in two opposite directions thereby compressing said spring when said plunger is moved to cushion the movement of said plunger and said main supporting arm, latch means for securing the main supporting arm in the end positions of travel of said plunger, a horizontal tube holder arm pivotally attached to said main supporting arm, and a stay rod pivotally attached to said tube holder arm and to a fixed pivot mounted on the supporting base level with the horizontal spindle and so spaced therefrom that the stay-rod extends parallel to the main supporting arm whereby said tube is movable to either of two preselected coaxial positions at two different focal distances from the plane of the cassette and is aligned with the center of the cassette at either position.

ANTHONY NEMET.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,000,497 Pohl May 7, 1935 2,133,738 Chaoul Oct. 18, 1938 2,156,170 Augustin et al. Apr. 25, 1939 2,181,620 Haupt Nov. 28, 1939 2,353,145 Chamberlain, Jr. July 11, 1944 2,412,662 Watson Dec. 17, 1946 FOREIGN PATENTS Number Country Date 134,830 Australia Oct. 10, 1933

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