US2400516A - Apparatus and method for sectional radiography - Google Patents

Description

APPARATUS AND METHOD FOR SECTIONAL RADI OGRAPHY May'21,- 1946.' J. KIEFFER 2,400,516

Filed July 20, 1943' 5 Sheets-Sheet- 1 P," Tamar. l,-- k Fume FOC S INVENTOR. KIEFFER ATTORNEY- PLANE IN Ma 21, 1946. E F E I 2,400,516

' HPARATUS AND METHOD FOR SECTIONAL nanioenuny Filed July 20.1945 s Sheets-Sheet 2 9781- *T 1 mwzmoa,

( q q o v 4 JEANKI FFER I 11 -BY ATTOR NEYf y J. KIEFFER 2,400,516 APPARATUS AND METHOD F011 SE GTIONAL RADIdGRAPl-XY V Filed July 20, 1945 :s Sheets-Sheet :5

INVENTOR. JEAN K/EFFER Patented May 21, 1946 UNITED- srA E mettle si PATENT ore-l ce APPARATUSAND METHODFOR SECTIONAL RADIOGRAPHY Jean Kieffer, Norwich, Connh Application'duly'20, 1943, Serial-No; 4%;415-

16 Claims. (01

This invention" relates to an apparatus and method for sectional radiography;

Heretofore, sectional radiography has been principally used'for making skiagraphs of thin layers or laminae of the human body, known as animate objects, for in the apparatus in which the X-ray-tube had to be moved, the huge size and massiveweight ofthe'tubes and associated equipment needed greatly hindered synchronous movement. This equipment ordinarily included a high tension transformer which, with the tube,

was immersed in an oil tank. The mass of the tube and equipment was so great that any movement thereof placed too great a strain upon the supports, and 'in' addition required'too complicated a system of moving heavy duty supports; electric wiring and cooling conduits. On the other hand, in the apparatus in which'the'object being radiographed was rotated withoutbodily' shifting, it was impossible to'blur-eliminate'shad ows of dense portions of the object immediately above or below the axis of rotation and, in general, in such apparatus dissemination of unwanted shadows by blurring'could not be accomplished as widely and uniformly as might be required. The possibility of keeping the tube stationary was suggested in my Letters Patent No. 1,954,321. 7,

However, to date, as far as lam aware, and despite the desirability of employingmassive X-ray' tubes in sectional radiography, .no apparatus or:

method capableof taking-clear sectional radio-'- graphs with a'stationary tube has been developed.

It is, accordingly, an object of the present invention to provide aniapparatusand method'f or sectional radiography wherein an 'X ray tubeis.

maintained stationary but the radiographed' object and film are so manipulated as to substantially eliminate all undesired shadows.

Sectional radiography of inanimate objects is difiicult, since it is not easy to disassociate the shadows of a desired planeportionof an intricate structure from the shadows of the 'overlyingand underlying portions; Ofttimes complex'moti'ons of the radiographed' object and film arerequiredand I have found-that such motions 1 areonlybodily shifted so that all undesired "shadows are uniformly moved and dispersed to' the same degree. It is, therefore, afurther objectoi my invention to provide a method'and apparatus for sectional radiography wherein both the fi'lm and object are bodily shifted, while-the tube-remains stationary.- j I In my previous patent's, No. 95432 1, forXray device and method-of technique; No; 2,167,114, for X-ray device, and No.2,167,1'15'} for-Radiation method and apparatus, wherein the-objeot' being radiographed' is held stationary-and the X-ray tube and X-ray filmmoved in parallel planes; I- have showna variety of 'motion's for the tube and film, including linear, circular, sinusoidal and spiral. It is a further object of the'present-invention to'provide, in an apparatus-wherein the-fi-lm and radiographed object are bodily shifted and the'X-ray tube maintained" stationary; various types of. bodily movements for the object and film corresponding to those disclosedintheaforesaid patents, ,so as to enable-employment of" a movement best suited for obtaining 'cl'earsectional radiographs: having" widely and". uniformly dispersed. extraneous shadows. Eor someiinani mate objects simple linear bodily translation of the object and film sufiices to: obtain clear sectional radiographs; More: complex object's re quire a more intricateLmOtiQn whichimay; include a combination ofilinear: bodily; translation and uniform. or harmonic: bodily movement at I an angle to the translation, or bodily. shifting in -a' circular or spiral patheitherfwith'" or'fwithout linear translation; The specific motionaselected in each case will dependiupon theznature of the object being. radiographed and-the plane whose skiagraphis .tobe taken.

An additional object oftheinventioniis to'provide an apparatus and method whichcomprises relatively few and simple r parts, is rugged and durable in operation; and lendsv itself. readily. to

a bodilyplane movementof an object and film best adapted to, take sharp,; clea-randdistinct sectional radiographs.

Still another object of the invention is to providev an apparatus. and method of the character describ'edfor serial sectionalradiog-raphy of a plurality of inanimateobjects successively scanned by a stationaryX-Jray.tube. v

A further object .ofthe invention .is to. provide an apparatusand m'eth'odfof the character. de-

scribed capable of simultaneously taking a plu ralityi of "sectional radiographs of spaced planes efi'ective when lioth the object and the film are ofeachof a series of inanimate objects succes sively scanned by a'stationary X raytube;

Other objects of the invention will in part be obvious and in part hereinafter pointed out.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts which will be exemplified in the constructions hereinafter described, and of which the scope of application will be indicated in the appended claims.

In the description and claims the termFX-ray connotes, in addition to the conventional definition of a Roentgen ray, any radiation which is capable, after penetrating a substance and being absorbed therein in different degrees, of forming a latent, virtual or real image in a suitable medium.

The terms film and plate broadly denote such a medium. This medium may be in the usual form of a pellucid carrier through which there are uniformly dispersed particles photochemically sensitive to X-rays. Another standard form is a fluorescent screen which is luminously activated by X-rays. In general, therefore, the term film or plate embraces any medium upon which an image can be optically realized either coincident with impingement of X-rays or I subsequent thereto.

The terms plane movement and planar movement denote movement of a body such that a section thereof travels in a single plane.

The term in parallel planes as applied to movement denotes motion of two bodies in such fashion that portions thereof parallel to the direction of motion move parallel to each other.

The terms bodily and bodily shifting denote movement wherein each element of an object travels parallel to every other element and at the same instantaneous linear speed. Put in another way, if a set of coordinate axes are drawn through any point of the object, these axes do not change their direction as the object bodily shifts. It is to be understood, however, that bodily movement may be combined with other types of movement, as for example, simple rotation.

In the accompanying drawings in which are shown various possible embodiments of the present invention,

Fig. l is a side elevational view of an apparatus embodying one form of my invention;

Fig. 2 is a top plan View thereof;

Fig. 3 is a fragmentary oblique View of the plate supporting mount and is illustrative of the means by which the plate can be tilted to secure angled transverse sectional radiographs;

Fig. 4 is a diagram illustrating the principle of operation of the instant invention;

Fig. 5 is an oblique view of .an apparatus embodying a modified form of the invention with portions thereof broken away to show constructional details;

Fig. 6 is a schematic side elevational view of another modified form of my invention which is adapted to take sectional radiographs of a series of continuously moving inanimate objects;

Fig. 7 is a top plan View of the apparatus illustrated in Fig. 6; and r Fig. 8 is a schematic drawing of an apparatus 7 embodying yet another modified form of my invention which is adapted to simultaneously take a plurality of radiographs of spaced planes of a series of continuously moving inanimate objects.

In general, I accomplish thebasic objects of my invention by providing an X-ray tube which remains stationary during radiographing and two separate supporting means, one for the objectbeing radiographed and the other for the film. Means is further provided to bodily shift the two supporting means in parallel planes and at such relative speeds that a point in a plane of an objeot to be sectionally radiographed sweeps past the target of the X-ray tube at the same instantaneous angular speed at which a point on the film moves angularly past the target. By employing a stationary X-ray tube, I do away with the movement thereof, heretofore generally believed necessary to the practice of sectional radiography. With the X-ray tube stationary, the large 30 to 1000 kv. tubes requisite for industrial radiography can be simply mounted, and there is no need for establishing any moving connection between the machine proper and the tube, although the tube and its associated equipment, may themselves be moved. By employing bodily shiftable supporting means for the inanimate object and film, all types of intricate plane motion may be imparted, and that particular motion selected which is best adapted to eliminate, by blurring, all shadows of dense portions of the object above and below the plane to be radiographed.

Referring now to the drawings and more particularly to Figs. 1 through 3, I have there illustrated a simple apparatus it which embodies the present invention and in which both the film and object being radiographed are merely bodily translated. Said apparatus comprises a bed 12 supported by legs M. In the upper surface of the bed are formed two pairs of parallel grooves I5, I 8.

The outer hair of grooves it serve as tracks to guide the movement of a, lead-shielded carriage 28 on which an inanimate object O is supported. Said carriage 28 has a plurality of rollers 22 which ride in the grooves Hi. It will be obvious that with this construction the carriage is restricted to bodily movement along a straight line in a plane parallel to the top of the bed P2. The

top of the carriage 20 is provided with an aperture 24, in which there is inset a Bakelite panel 26 large enough to support any object desired to be sectionally radiographed.

Beneath the carriage 29 is a second carriage 28, whose top is preferably substantially parallel to that of the first carriage 28. The second carriage 28 is supported on roller 33 which ride in the grooves l8. In thi manner I constrain the movement of the two carriages 29, 28 along parallel straight line in spaced parallel planes.

The carriage 28 supports a film F, carried in a mounting 32, one end of which is hinged to said carriage. The other end of the mounting is pivotally connected to a link 36 having a longitudinal slot 38. A horizontal screw 40 carried beneath the carriage 28 freely passes through said slot 38, and may be clamped in any position by a wing nut 42. I provide this mean for inclining the film F for a purpose hereinafter described. It may be mentioned at this time, however, that when it is desired to substantially tilt the film the Bakelite panel 26 can be lifted out of its aperture 24.

It will be appreciated that, owing to the nature of the supports for the carriages, the object and film F, regardless of the inclination of the film, are only capable of parallel plane movement.

The means for bodily shifting the object carriage 20 and film carriage 28 at their proper relative speeds comprises a heavy link 44 which i rotatably mounted on a pivot 46 supported on a stationary part of the apparatus, such as an extension 54''! son one of :the leg i4} Said zlink 4.4 has anelongated'slot til-formed therein :which is adapted :to slidably receive two .pins 4.9, 35%. One:of these pins 49 is=rigidlytconnected .tolthe film carriage 2813111613118 .other;to theobject carriage 20. Either of 'thezpins, as fforiexampleithe pin 59, may .be so mounted on its suppoytingcarriage that, although capable of .rigid connection therewith, it fromthe pivot 4%. This may :be:accom-plishediby providing 011 the object carriage '29 a depending post 52' of non-circular cross section on "which there is slidably mounteda collar 15% having a finger Edextending in;the..direction of the link M and to which finger thegpin ilisvafiixed. butterfly screw 158 in the collar 5 s rves 'to set the pin 50 at any selected distancefromithe piyot 46. It will be apparent that when the link "44 is oscillated about the pivot -45, thetwop ns 9, 58, and, therefore, the'ifilmgandobject carriages 28, 2c, will move in parallelspath and at relative rates of speeds, which are directly proportional to the distance of said pins from the pivot 46.

The apparatus lflnalso includes aniXerayltube 60 mounted in a housings whichis rotatably supported in a yoke 64 secured to theend of. an armzfi .which is flexibly carried on a post '68 for universal movement inconventional manner. The illustration and description of theX-ray tubeiand its mount are conventional, and it will beappreciated that the heavier type of X-ray tubes'and their companion equipment, such .as transformers, may be mounted in any'manner well known to the art. .It suffices for the purposes of the present invention that the tube is not connected for synchronous .movementrelative to either carriage 2H, '23. It .is preferable, however, to have the tube .tiltable and to have either the .tube or the carriage so mounted .that their position may be relatively adjusted for sectionally radiographing transverse plane by the decentering method hereinafter described.

Any suitable means may be employed for moving the link as, and thus translating the object carriage 2i) and film carriage 28. Such means may comprise an electric motor-l0 mounted on a. leg [4 and having a gear E2 which drives a sector rack 14 on said link.

In Fig. 41 have diagrammatically illustrated the principle upon which the present invention operates. In this figure T represents the emitting target of an X-ray tube, ,0 the inanimate object to be sectionally radiographed, and F the film on which the radiographvis to be visually realized. P represents the planeoi the inanimate object O whichis to be sectionally radiographed. The film and inanimate object are shown in two positions. The one infullzlines represents an early position of the film and object when the entire object is between thetarget and film. The one in dotted lines denotes the respective positions of the filmand object after a. period of movement. 0 indicates-a point in the plane of the object which is to be radiographed. Another point a is in the same object 0 directly beneath the point 0. At the time that the film and object are in their initial position, a ray emanating from the target '1 and passing through-the point 0 will also pass through the point vq and strike the film F at a point). The latent image formed at this instant will thus'be thesuperimposed shadows ofthe points 0 and c. When the object. andf'film'have moved at predetermined ldifferent ratestof' speed for a "period may be shifted toward iand-a-way of time they'willi-re'achitheirdotted line .'posi-' tions. [At suchtime the point I will have moved to f, the point 0 to o',:and the point :11 to q. The positions of the points 0 and f are such that a ray emanating from the fixed target T will pass in a straight line through 0' and f. However, a ray passing through the point q will strike the film at a new point f". 'LThus the shadoW-of the point q willblur during movementof the fiim and inanimate object through the respective distances if, 00.

It will thus be seen that the relative rates of speed of the object O and film F to secure sectional radiography of said object along a plane P must be so selected that said object and film as they are bodily shifted along paralle1 spaced planes simultaneously sweep through the same angles about the target T. A more exact method of expressing this same relationship between the target, plane of sectional radiography, and, film, is that the triangles'formed with the target as the vertex, and the distances travelled of points in the film and selected plane as the bases must be similar. This can be mathematically expressed in the following ratio: TozTfzzoozff. It will now be apparent that to sectionally radiograph a plane parallel to the plane P and including the. point q,

it is necessary to move the inanimate object O through a distance qq instead of a distance 00' while the film is moved through a distance ff. Under these conditions the shadow ofthe point 0 on the film F would be blurred. It will also be appreciated that the distances 00', qq" andff', instead of merely representing space traversed, may denote velocities of travel; that is 00 may represent acertain distance per unit of time, and co" and ff distances for the same unit of time.

Referring back nowyto Fig. 1, I have there rep-. resented the distance along a straight line from the target T of the -X-ray tube to the plane P in focus by the reference character A and the distance along the same; line from the plane P to the-plane of the film F by the referencecharacter B. The distance through which the inanimate object 0 moves during a given period of time has been represented by the reference character E, and the distance through whichthe film moves in the same unit of time by the reference character G. From similar triangles the equation governing the relationship between these variables is:

To secure relative movement of the inanimate object and film in accordance with this equation, it is merely necessary to set the collar 54 a'proper distance away from the pivot 46. I

The perpendicular distance from the pivot 46 to the path of movement of the pin 56) for the object carriage 2B is represented by the reference character D and the perpendicular distance between the paths of movement of the object-pin :0 :End the film pin 49 by the reference characer. I

It willbe apparent that the object pin 5t moves at the same rate of speed as the object O and the film pin 48 moves at the same rate of speed as the film F. Therefore, when the object has moved a distance E, the object pin 50 will have moved a similar distance E and the film pin 8 a distance G. From similar triangles the equation governing the motion of the link 44 and pins 48 and 50 is:

To obtain the relationship between the position of the pins 48 and 50 and the relative spacing between the target T, film F and plane P to be radiographed, the value of are.

secured from either the equation governing the motion of the link 44 or the equation governing the motion of the film and object, is substituted in the other equation. The following equation results:

A+B C'+D Solving for B we have:

where (3- equals the velocity of the film and E, the velocity of the object. This equation is more general as it does not include any variables dependent upon a particular means for moving the film and object.

If a transverse section of an object which is too long for sectional radiography is to be taken, I may arrange the apparatus I so as to take a radiograph of the desired plane by employing a decentering method. In accordance with this method, the film and object, instead of moving in such manner that the X-rays emanating from the target T have to pass through substantially the entire object, are so arranged that the X-rays need only pass th'rough a portion of the object at an angle to the longitudinal axis thereof. Pursuant to this method, I bolt the elongated object to the carriage 20 at a point spaced from the aperture 24 in which the Bakelite panel 26 is disposed, a plurality of apertures 15 being provided in the carriage for such purpose. In this position the film is disposed to one side of the object. The I i-ray housing 62 is swung about the post 68 so that the target lies to the other side of the object. The arm 66 is rotated and the housing 62 turned in the yoke 64 so that X-rays emanating from the target are directed through the portion of the object to be sectionally radiographed and toward the film F. The object and film are then bodily shifted at relative rates of speed satisfying the equation The foregoing method of decentering may be practiced with the film lying either flat, as indicated in Fig. l, or tilted, as indicated in Fig. 3. Where the film is horizontal, the transverse plane will also .be horizontal, and where the film is tilted, the transverse plane radiographed will be include longitudinal struts 90 extending generally in the direction of the rails and connected by transverse parallel rails 92. These latter rails serve as tracks for rollers 94 of an object table 96. With this construction it will be apparent that the object table 96 is capable of any planar movement having components parallel to the longitudinal rails 85 and transverse rails 92.

The longitudinal rails 85 also support the rollers 98 of a film carriage I00 comprising struts I02 extending in the general direction of the rails 85. These struts are connected by transverse parallel rails I04 which serve as tracks for the rollers I06 of a carrier I08 for a film F. The film F, like the table 96, is thus capable of any planar movement having components parallel to the longitudinal rails 85 and the transverse rails I04.

Means is provided for insuring movement of the film F and object table 96 at relative-rates of speed satisfying the equation Mpg-1 Such means may comprise a linkage system including a shaft I I0 universally pivoted to a cross rail II2 by a gimbal II4 pinned to said shaft. Another gimbal II6, slidably received on the upper reach of the shaft, i secured to an arm H8 extending from the film frame I08. Still another gimbal I20 is slidably received on the shaft intermediate the gimbals H4 and H6. This intermediate gimbal is secured to a bar I22 slidably but non-rotatably mounted on a leg I 24 pendent from the object table 96. The bar I22 may be held in selected position by means of a wing set screw I26.

Since thefilm frame I 08and object table 96 move in parallel planes, the ratio of their speeds controlled by the linkage system will be:

'G C+D' where D is the distance between the gimbals H4 and I20 and C is the distance between the gimbals H6 and I20.

The X-ray tube is not shown in conjunction with the device 80, but it will be understood that the same may be imilar to that shown in the first form of my invention. The plane radiographed in any object carried by the table 96 will be determined by the relative positions of the object, target, and film, the angular position of the film and the distances between the three gimbals H4, H6, and I20.

Still further, in accordance with my invention, I provide means for actuating the object table 96 or film frame I00, their relative motion being, of course, controlled by the shaft IIO. Such means comprises a motor I20 which, with its associated gear housing I30, is mounted for slidable movement longitudinally of the bed 82 by dovetailed legs (not shown) received in the ways I32 of a plate I34 straddling the legs 84. In the lower end I36 of the gear housing is a variable speed control which drives a sheave I38 whose speed is governed by a lever handle I40. A wire cable I42 is wrapped at least twice about the sheave and has its ends secured to spaced fixed pins I44 pendent from the plate I32. I also provide a reversing mechanism controlled by a lever handle I46 and a clutch mechanism controlled by a lever handle I48. It will be seen that when the sheave is turned it will pull the motor along the plate I34 parallel to the longitudinal rails 85.

slidablysecured.to-said axles nearthe ends of the rollers 196,19Band-which are made rigid by of the shaft. Said-shaft 11521 journalledin a bearing .ldslida-bly mounted bya dovetailed leg 162111 a wayflfili of a-plate .16? bridging the'legs 84. 3A templet cam 158 similar :to that "shown finfmy United lStateS LettersPatent Nos. 2,167,114

:and 2,167,116 ilSflOOSElY mounted on the shaft 152. Said. cam has' atspiralled; groove .in its upper surface and is ipreventedirfrom :rotating relative 'tolthe drive shaft i152 by .ipins *'169.slidable in a -slot 1111 :in "the upper edge oi the plate iiil. .Abovethecam 168.:adisk 1'12, keyed to the shaft 11.52,:inc1udes .a radial .fslot 1-'14 .andia plurality of radially arranged :holes 1115 adapted .to receive afpin 1'18. :Whenithetpinds placed ina hole,

..it'.will1'lot:extend intotthe groove in the cam :1'58, 750 that :rotation:;of the disk 112 will cause the pin 118 to travel in a circularypath. On the iotherihand, when the .pin is .placed in the 'slot 1'14, a .portion of reduced diameter extends therethrough and "is received into the spiral channelo'f the Team 1 58, so that rotation of the disk 11-2 will-causethe :pin 178 to 'move in a spiral path governed by the shape of theggroove. "The construction of a pin adapted to cooperate in the foregoing manner is fully described in my two aforementioned patents. Thepin is set into an extension l fifi rigldly secured to the table 913, so that any'motion'imparted to the pin will be transferred'ito the :table .and'through the shaft 1 16 tothe film frame I 118.

It :will'be appreciated that'bywmanipulation of the various .lever handles 1316,-'1%5,1i8,154, and 158, an extremely "Wide variety of motions can be imparted to saidpinandinturn to the object and film. 1

In Figs. .6. and 7:1 have-schematically illustrated another :modified form of apparatus 1% which is specially adapted to secure sectional radiographs ofa series of continuously:moving inanimate objects. This apparatus, unlike that shown in the-earlier described forms of the invention, imparts to both thefilm and objects-motion having a component which continuously proceeds in .thesame .direction, .-so that thereneeclbe no interruptionof radiography to restore the supporting andmoving parts .for the filmand object to their-initialpositions. This may be accomplished, in general, byemployinga vconveyorbelt system for moving objects to and past the X-rawtube and by using spools tomove a-strip of film beneaththe objects.

.Referringnow in detail to Figs. -6 and '7, the apparatus 190 comprises a pair of side frames 192, 194 which serve as supports .for the conveyorlbelt system and the film system.

The conveyor.beltrsystemincludes two parallel spaced .rollers 196,188, Whose axles 2110, 292 are s'li'dably journalled in the side frames 1-92, 1.94, One of the axles, for example, .2il2, is driven by a motor 204 through a chain 205 which engages a pulley 208 slidably keyed :to the axle 2112 and rotatably but non-shiftably held to the side frame 194. The oppositeendzof this axle extends be -yond the'other:side .frame 192 1 and: carries afixed collar 2113 which rides in the;;gr oov .212 ofra'barrel :cam. 2 l4',turned through a gear train :2 16 "by anotherxmotor 218. The :two axles .2139, 2oz are rigidly connected for unitary transverse shiftin -by struts 220, whose opposite ends are noncross bars 222, :It will thus b seen that while the conveyor belt 224 is beingdriven to progressively advance a series of inanimate objects 0 from theroller 198 to the roller 195, said rollers and belt will be bodily reciprocated transversely of the axles 2%, 2112 in accordance-with a cycle determined by the contour ofthe cam groove 212.

The film system comprises a pair of film spools 225, 222! whose axles 230, 232 are rotatably and slidably journalled in the side frames -192, 194. A helical spring belt 234 connects pulleys 235 and 238 on the roller 198 and take-up spool 228 thereby providing an impositive drive for the film takeup'228. For advancing thestripfilm S Iemploy a pair of sprockets 240 which engage perforations P at thesidesof said film. .These sprockets are driven from the axle .2112 through-a gear train 262 in whichgearsareadapted to be replaced'in any well kn-ownmanner to vary th angular speed of the sprockets 241]. ..Aconventionaldrag may be placed upon the .axle 23fl to which the supply spool 225v is .affixedto keep the film tautbetween said .spool and .thespro'ckets 241i. The film is maintained taut between thesprockets and the take-up spool 22.8 by driving theaxle'232 faster than the-film .is moved by'the sprockets. lhe spools 226, 228 and the .sprockets 2411 are tied together for unitary lateral shifting by struts 244 rotatably but .nonslidably secured to the axles 235, 232 andsaidsprockets a-nd rigidified by cross bars 246. I

It will now be apparent-that owing to the different ratesof speed at which-the objects 0 and strip film S pass-beneath an 'X-ray tube 248, a

sectional radiograph will be secured of each ob- .ject 0 on the conveyor belt 224. The plane of this object will be the lone satisfying the equation that the gear train 24-2 must be selected to impart arate of travel to the film faster than the rate of travel of the conveyor belt.

In accordance-with another feature of my invention, the film and conveyor belt may be bodily transversely shifted at relative rates of speeds also satisfying the foregoing equation. To this end I may employ a linkage system similar to that shown'in the first form of the invention. Said system includes a slotted link 2511 pivoted at one end to'a side frame 192. At the far end of'the slot a pin 2521s received which is secured to the outer race of a ball bearing 254 whose inner-race is fixed to the axle 23l'lof the film spool 225. The topof said pin'is headed to prevent it from slipping out of the slot. The inner race of anotheriballbearing 256 is fixed to the axle The outer race of isreceived in the slot of thelink 251i intermediate the'pin 254 and the fulcrum of the link. This second pin 260 is also headed "to prevent it from "slipping'outof'the slot. A'set'screw 252 holds'the linking in anyadjusted'position.

It will be seen: from :the discussion of the principles'governin'g the .operation'of'lthe link in the first form of the invention that the pin 251! should be so set that the ratio of the transverse speeds of the film and series of objects will be similar to the ratio of the longitudinal spe ds of the film and objects, i. e., G:E. In this manner the transverse as well as the longitudinal movement of the film and objects will cause the same plane to be in focus.

If the objects are of such construction that transverse movement is not required to obtain a clear sectional radiograph, the motor 218 may be stopped.

The film system may be housed in a light-proof casing 264 through which the axles 239, 232 protrude. The top of the housing carries an adjustable lead mask 266 having an aperture 268 which is covered with a panel of Bakelite are, said aperture lying beneath the X-ray tube 212. The time of exposure for the film is controlled by the rate of travel of the film and the length of the aperture 268 parallel to the direction of film travel between the spools 226, 228. The aperture length can be changed by adjusting the mask 266. By way of example, if the speed of the film past the aperture 268 is one inch per second, and the length of the aperture thirty inches, the period of film exposure will be thirty seconds.

Instead of sectionally radiographing only one plane of a series of continuously moving objects in the manner just described, I may simultaneously sectionally radiograph a plurality of planes and in Fig. 8 I have schematically illustrated an apparatus 280 capable of performing in such manner. The conveyor system of this apparatus is similar to that just described, difiering therefrom only in that in place of a single supply and take-up spool there are provided a plurality of supply spools 282, 284, and 286, and a plurality of take-up spools 288, 296, and 292. All of the take-up spools are actuated from the driving conveyor roll 294 through a series of gears 295 indicated by the dot and dash circles. The gears 296, 298 and 309 on each take-up spool 292, 290, and 288, turn its associated spool through a friction slip drive (not shown). The several strip films S, S", and S', are driven at various rates of speed by sprockets 302, 364, and 306, which are actuated by a driving train (not shown) starting from the roller 294. Said driving train is so constructed, in any fashion well known in the art, that the speed of each of the sprockets 392, 364, 396 can be adjusted to secure a different plane in focus on each of the strips S, S", S' in accordance with the formula In addition to the adjustable lead mask 368 on top of the light-proof housing 3H) for the film system which serves to define an aperture 3 for governing the exposure time of the top film S, I may also provide a separate adjustable lead mask 3l2, 3|4 for each of the other strip films S", S'. As indicated in Fig. 8, the masks should be arranged so that successively smaller apertures underlie one another. However, the relative physical position of the strip films S, S" and S' does not necessarily correspond to the rela-- tive physical position of the planes sectionally radiographed thereon; that is, the top film S need not have a sectional radiograph of the uppermost plane latently formed therein, but may have a sectional radiograph of a lower plane, whereas the second strip film S" may take the radiograph of the uppermost plane, since the plane radiographed on any film is governed by the equation G B: A 1) It will be appreciated that with this construction sectional radiographs of difierent levels of objects can easily be given different exposures, selected to obtain the best results with various thicknesses, weights and densities of parts at such levels. If all radiographs are to have the same exposure the length of the openings in each mask should be adjusted to be directly proportional to the speed of the film directly under it.

If desired, a plurality of independent linkage systems (not shown), like that described with reference to Figs. 6 and 7, may be employed to impart transverse motion to each set of associated supply and take-up spools, which bears the same ratio to a transverse motion imparted to the conveyor belt that the longitudinal rate of travel of such set bears to the linear rate of travel of the conveyor belt.

Decentered transverse, views through the objects, either parallel to the plane of travel of the conveyor belt or at an angle thereto, may be obtained by oppositely offsetting the film system andtarget and, optionally, by angularly inclining the film.

It will thus be seen that I have described methods and apparatuses which achieve the several objects of this invention and are well adapted to meet the conditions of practical use.

As various possible embodiments, other than those described, might be made of the foregoing invention, and as various changes might be made in the embodiments set forth, it is to be understood that all matter herein set forth and/or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. A method of taking a plane sectional radiograph of an object comprising bodily shifting the object and film along straight lines in parallel planes and in the same direction relative to a stationary X-ray tube at such relative speeds that a point in the plane section to be radiographed and a point in the film sweep past the target of the tube at the same instantaneous angular speed whereby the shadow of each point in said plane section moves at the same instantaneous angular speed as the corresponding point in the film on which said plane section is being radiographed, and the shadows of points outside of the plane section move at instantaneous angular speeds which differ from those of the instantaneous angular speeds of the points in said section and in said film.

2. A method of taking a plane sectional radiograph of an object comprising bodily shifting the object and film in parallel planes and in the same direction relative to a stationary X-ray tube at such relative speeds that where A is the distance from a plane to be sectionally radiographed to the target of the tube, B the distance from said plane to the film, E the speed of the object at any instant, and G the speed of the film at the same instant whereby the shadow of each point in the plane to be sectionally radiographed moves at the same instantaneous in the same direction relativeto a stationary X- ray tube at such relative speeds that B A -l where A is. the distance from a plane to besee-- tionally radiographed to-the targetv of the tube, B the distance from said plane to the film, Ethe speed of the objects at any instant, and G1 the speed. of the film at the same instant whereby the shadow of each point in each object inthe, plane to be sectionally radio'graphed moves at: the same instantaneous angular speed as the corresponding point in the film on'which said plane is being radiographed, and the shadows of points outside of'the plane being sectionally radiographed' move at instantaneous angular speeds which'differ from thoseof the instantaneous angularspeeds of the points in said section and in said film.

4. A method as set forth in claim 3 wherein at the same time that the film and objects arecontinuously bodily shifted to and beyond the X-ray tube they are moved laterally back and forth undersaid tube, the ratio of the last named movement of the film and objects also being 5. A method of simultaneously taking a plurality of plane sectional radiographs of an object comprising bodily shifting the object and a plurality of films in parallel planes and in the same direction relative to a stationary X-ray tube at such' relative speeds that l r G shr ll where A1 An are the distances from the planes to be sectionally radiographed to the target of the tube, B1 Bn the corresponding distances from each of said planes to the corre sponding films, E the speed of the object at any instant, and G1 Gr. the correspondhigspeeds of the films at the same instant whereby" the shadow of each point in each plane to be sectionally radiographed moves at the same-instantaneous angular speed as the corresponding point in the corresponding film on which said planes are being radiographed, and the shadows of points outside of the planes being sectionally radiographed move at instantaneous angular speeds which difier from those of the instantaneous angular speeds of the points in said sections and in said films.

6. A method of taking aplurality of plane sectional radiographs of each of a series of objects on strip films comprising continuously bodily shifting the objects of said series and said strip films in parallel planes and in the same direction relative to a stationary X-ray tube at such relative speeds that where A1 An are the distances from the planes to be sectionally radiographed to 'the target; of; the tube; 131. Bn the corresponding distances from each of said planes to the corresponding films, E thespeed of the objects at any instant, and G1 Gn the corresponding speeds of theifilms at the same instant whereby the shadow of eachpoint in each object in each plane to be sectionally radiographed moves at the same instantaneous angular speed'as the corresponding point in the corresponding film on which said planes are being radiographed, and the shadows of points outside of the planes being sectionally radiographed move at instantaneous angular speeds which difier from those of the instantaneousangularspeeds of the points in said sections and in said films.

7-. An apparatus for taking a sectional radiograph of an object with an X-ray tube which remains stationary during radiography, said apparatus comprising means to support an object, means to support a film, and means to bodily shift said object-supporting means and said film-supporting means in parallel-planes and in the same direction relative to the stationary X-ray tube at such relative speeds that align where A is the distance from a plane to be seetionally radiographed to the target of the tube, B the distance from said plane to the film, Ethe speed of the object at any instant, and G the speed'of thefilm at the same instant.

'8. An apparatus for taking a sectional radiograph of an object with an X-ray tube which remains stationary during radiography, said apparatus comprising means to support an. object, means to support a film, and means to bodily shift said object-supporting means and said film-supportin means along any selected one of a plurality of different paths in parallel planes and in the' same direction relative to the stationary X- ray tube at'such relative speeds that where A is the distance from a plane to be sectionally radiographed to the target of the tube, B the distance from said plane to the film, E the speed of the object at any instant, and G the speed'of, the film at the same instant. I

9. An apparatus for taking a sectional radiograph of an object with an X-ray tube which remains stationary during radiography, said apparatus comprising means to support an object, means to support a film,and'means to bodily shift said object-supporting means and said film-supporting means along straight lines in parallel planes and in the same direction relative to the stationary X-ray tube at such relative speeds that where A is the distance from a plane to be seetionally radiographed to the target of the tube, B

the'distance from said plane to the film, E the planes and in the' same direction relative to the stationary X-ray tube at such relative speeds that where A is the distance from a plane to be sectionally radiographed to the target of the tube, B the distance from said plane to the film, E the speed of the object at any instant, and G the speed of the film at the same instant.

11. An apparatus for taking a plane sectional radiograph of a series of objects with an X-ray tube which remains stationary during radiography, said apparatus comprising a conveyor belt, means to hold a supply of strip film beneath said belt, means to take up said strip film, means to actuate said conveyor belt and take-up means so as to bodily shift the series of objects and strip film in parallel planes and in the same direction relative to the stationary X-ray tube at such relative speeds that G B=A 1) where A is the distance from a plane to be sectionally radiographed to the target of the tube, B the distance from said plane to the film, E the speed'of the objects at any instant, and G the speed of the film at the same instant.

12. An apparatus as set forth in claim 11 wherein means is provided for laterally bodily shifting the strip film and conveyor belt back and forth at the same time that they are moved by the actuating means and at the same ratio speeds,

13. An apparatus for simultaneously taking a plurality of plane sectional radiographs of an object with an X-ray tube which remains stationary during radiography, said apparatus comprising means to support an object, a plurality of means each of which supports a different film, and means to bodily shift said object-supporting means and each of said film-supporting means in parallel planes and in the same direction relative to the stationary X-ray tube at such relative speeds that where A1 An are the distances from the planes to be sectionally radiographed to the target of the tube, B1 Bn the corresponding distances from each of said planes to the corresponding films, E the speed of the object at any instant, and G1 Gn the corresponding speeds of the films at the same instant.

14. An apparatus for taking a plurality of plane sectional radiographs of each of a series of objects with an X-ray tube which remains stationary during radiography, said apparatus comprising a conveyor belt, a plurality of means each of which holds a separate supply of strip film beneath said belt, a plurality of separate means each of Which takes up a different strip film, means to actuate said conveyor belt and take-up means so as to bodily shift the series of objects and strip films in parallel planes and in the same direction relative to the stationary X-ray tube at such relative speeds that Basra-4 radiographs of a series of objects on film with an X-ray tube which remains stationary during radiography, said apparatus comprising means to support said objects between film and tube and means to continuously bodily shift said object supporting means and film in parallel planes and in the same direction through the field of radiation of the stationary X-ray tube at such relative speeds that G B A 1) where A is the distance from a plane to be seetionally radiographed to the target of the tube, B the distance from said plane to the film, E the speed of the objects at any instant, and G the speed of the film at the same instant.

16. An apparatus for taking a plurality of plane sectional radiograp-hs of each of a series of objects on underlying films with an X-ray tube which remains stationary during radiography, said apparatus comprising means to support said objects between the uppermost film and the tube and means to continuously bodily shift said object supporting means and films in parallel planes and in the same direction through the field of radiation of the stationary X-ray tube at such relative speeds that where A1 An are the distances from the planes to be sectionally radiographed to the target of the tube, B1 En the corresponding distances from each of said planes to the corresponding films, E the speed of the objects at any instant, and G1 Gn the corresponding speeds of the films at the same instant.

JEAN KIEF'FER.

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