US3156824A - X-ray collimator having visible light centering arrangement and an adjustable filter for X-rays - Google Patents

Description

Nov. 10, 1964 1.. F. PEYSER 3,156,824

X-RAY COLLIMATOR HAVING VISIBLE LIGHT CENTERING ARRANGEMENT AND AN ADJUSTABLE FILTER FOR X-RAYS Filed Dec. 1, 1960 2 Sheets-Sheet 1 ,3 FIG. I.

INVENTOR LEONARD F. PEYSER 10, 1964 1.. F. PEYSER 3,156,824

X-RAY COLLIMATOR HAVING VISIBLE LIGHT CENTERING ARRANGEMENT AND AN ADJUSTABLE FILTER FOR X-RAYS Filed Dec. 1, 1960 A 2 Sheets-Sheet 2 BEAM AXIS INVENTOR LEONARD F. PEYSER BY 2 E ATTORNEY.

United States Patent 3,156,824 X-RAY COLLIMATOR HAVING VISIBLE LIGHT CENTERIN G ARRANGEMENT AND AN ADJUST- ABLE FILTER FOR X-RAYS Leonard F. Peyser, White Plains, N.Y., assignor to Howdon Videx Products Corporation, Califon, N.J., a corporation of New Jersey Filed Dec. 1, 1960, Ser. No. 73,025 4 Claims. (Cl. 250-105) This invention relates to X-ray collimators.

In X-ray collimating devices having (visible) light centering arrangements, the attachment of the collimator to the machine is a difficult and time-consuming process, involving trial and error adjustment of the collimator to bring the axis of the beam into registry with the light beam. It is one object of the invention to provide an improved arrangement for registering the X-ray and light beams.

Such devices also have provision for inserting filters, these being detachable elements requiring storage space and also requiring openings for insertion and removal which create possibility of radiation leakage. It is an object of the invention to provide a self-contained variable filter mechanism, thus eliminating these disadvantages of prior devices.

The apparatus of the invention is generally similar to that disclosed in prior application Serial No. 29,764, filed May 17, 1960, for Collimator, now Patent No. 3,091,696, to which application reference may be made for details of construction which form no part of the present invention and are, therefore, not discussed herein.

A collimator embodying the invention in a preferred form is shown in the accompanying drawing, in which:

FIG. 1 is a side elevation of the collimator;

FIGS. 2, 3 and 4 are, respectively, front, side and plan elevations of the light source element, shown as removed from the collimator casing;

FIG. 5 is a section on line 5-5 of FIG. 1, showing the filter arrangement;

FIG. 6 is a side elevation of the mechanism of FIG. 5; and

FIG. 7 is a view similar to FIG. 5, but showing the parts in a different position.

The collimator, as shown in FIG. 1, attaches to an X-ray tube part by means of bolts 10, carried by upper member 11 which is secured to the collimator casing cover 12 by studs 13. The casing encloses the collimator elements which include two lower pairs 14 and 15 for defining a rectangular beam, as shown in detail in the prior application, above referred to, and also upper pairs 16 and 17, for also defining a rectangular beam. These collimator elements are adjustable for defining the X-ray beam 20 and may be adjusted by means of knobs 21 for varying the beam angle and area of exposure.

The visible light system includes a light source 22 and mirror 23, transparent to the X-rays and mounted for pivotal adjustment on trunnions 24. An arm 25 fixed to one of these trunnions and carrying a screw 26 passing through a slot 27 in the side casing wall 28 permits pivotal adjustment of the mirror in one plane of collimation, tightening the screw 26 fixing the mirror in its adjusted position. The light system adjustment in the other plane of collimation is accomplished by rocking the light source 22 in a manner described below.

Light source 22 conveniently takes the form of an incandescent bulb having an approximately point source filament 30. The bulb is carried in a bayonet socket 31 which is mounted for pivoting about the screws 32 and held in position by opposed set screws 33. As will be apparent, loosening one of the screws 33 and tightening the other will adjust the bulb 22, in the direction indicated by arrows in FIG. 5, this direction being at right angles to that aliorded by the pivotal mounting of the mirror 23.

Filament 30 is located symmetrically to the X-ray beam collimation center, with reference to the mirror 23, so that the light beam 35 is defined by the lower collimator plates 14, 15 in close registration to the X-ray beam 20.

The mounting 34 for the bayonet socket 31 is carried by a block 44 which also carries a pair of prongs 41 inserting into the usual outlet socket within the collimator casing, so that the entire unit shown in FIGS. 2-4 may be inserted and removed through an opening in the collimator casing bottom, being held in place by the prongs 41.

In installing the collimator, a single exposure to the X-ray beam serves to locate the X-ray beam 20. The light beam is now registered in one plane by pivotally adjusting the mirror 23 and in the other by pivotally adjusting the bulb 22, a procedure requiring only a few minutes.

As will be noted from FIG. 1, the top pair 16 of the upper collimating plates is slightly spaced from the bottom pair 17 of these plates and this space is utilized to accommodate the filter plate assembly 50.

This assembly, as best shown in FIGS. 5-7, comprises a horizontal supporting frame 51, which is generally L- shaped, comprising a plate 52 having depending flanges 53 secured to a scutcheon plate 54 which overlies the front wall 55 of the collimator casing and covers opening 56 therein, through which the entire filter assembly may be inserted and removed. Screws 57 and spacers 58 fix the frame 51 to the top 12 of the collimator casing, permitting easy removal of the assembly, whenever desired, by unscrewing the screws 57.

Pivotally carried on the leg 60 which is secured to the plate 52, and by means of pivot pin 61 are the three filter plates 62-64. Springs 65 anchored at 66 are attached to the plates 62-64 and urge them toward inactive position (position of plate 62 in FIG. 7). A ratchet wheel 67 is rotatably carried by the plate 52 and has three operating studs 68 spaced at 120 around .its periphery. These three studs are of varying height, as shown in FIG. 6, being adapted to engage, respectively, one, two or three of the filter plates 62-64. Thus, with the tallest stud in the plate engaging position of FIG. 5, all three plates 62-64 will be held in the X-ray beam path, while with the shortest stud 68 in this position, only the lowest plate 64 will be so held. When the intermediate stud 68 is in operation, plates 63 and 64 are operative (not illustrated) and plate 62 is inactive.

A knurled operating wheel 70 is attached to the ratchet wheel 67 for turning the latter, and is accessible through an opening in the scutcheon plate 54 along with the end of detent arm 71. This last element is pivoted to plate 52 at 72 and urged toward engaging position by a spring 73. The operating tip of arm 71 is forked, engaging the teeth of the ratchet wheel to prevent backward turning and also engaging in any of the cutouts 74, of the ratchet wheel to prevent turning in either direction. One of the cutouts 74 is positioned just ahead of each stud 68 for holding the ratchet wheel in position to put one, two or all three of the filter plates out of operation. The fourth cutout, 75, is positioned to hold the ratchet wheel in position to permit all three filter plates to move out of operating position. By pressing arm 71 and turning the wheel 70, the operator may thus select one, two, three or none of the filters 62-64. Wheel 72 may be suitably marked (e.g., numeral 4 in FIG. 6) but may also be operated even in the dark by moving successivelyfrom one position to the next, as the wheel is accurately in deXed and stops automatically in each of its four setting positions.

What is claimed is:

1. In an X-ray collimator having upper and lower sets of collimating plates for adjustably defining the X-ray beam, the upper set comprising two pairs of opposed plates, the plates of each pair being adjustable at right angles to the plates of the other pair and one said pair being positioned above the other said pair, an adjustable filter assembly comprising a filter plate, means pivotally mounting the said filter plate between the two said pairs of upper collimating elements and for swinging movement into and out of the beam path defined by the said elements.

2. In an X-ray collimator having upper and lower sets of collimating plates for adjustably defining the X-ray beam, the upper set comprising two pairs of opposed plates, the plates of each pair being adjustable at right angles to the plates of the other pair and one said pair being positioned above the other said pair, an adjustable filter assembly comprising a plurality of filter plates, means pivotall'y mounting the said filter plates between the two said pairs of upper collimating elements and for swinging movement selectively into and out of the beam path defined by the said elements.

3. In an X-ray collimator having upper and lower sets of collimating plates for adjustably defining the X-ray beam, the upper set comprising two pairs of opposed plates, the plates of each pair being adjustable at right angles to the plates of the other pair and one said pair 4 being positioned above the other said pair, an adjustable filter assembly comprising a plurality of filter plates, means pivotally mounting the said filter plates between the two said pairs of upper collimating elements and for swinging movement into and out of the beam path defined by the said elements, and ratchet means for swinging said plates singly and in combination into the said beam path.

4. An adjustable filter assembly according to claim 3 in which the said ratchet means comprises an operating Wheel operable in predetermined steps for swinging a plate into the said beam path when rotated through the first said step and swinging an additional filter plate into the said beam path during each succeeding step, and then returning all said filter plates to a position outside the beam path.

References Cited in the file of this patent UNITED STATES PATENTS 2,094,103 Harsley Sept. 28, 1937 2,204,465 Baier June 11, 1940 2,331,586 Waiscol Oct. 12, 1943 2,486,503 Stephens Nov. 1, 1949 2,881,329 Peyser Apr. 7, 1959 2,901,631 Hansen Aug. 25, 1959 2,911,537 Land Nov. 3, 1959 FOREIGN PATENTS 432,220 Germany Aug. 3, 1926

Claims (1)

1. IN AN X-RAY COLLIMATOR HAVING UPPER AND LOWER SETS OF COLLIMATING PLATES FOR ADJUSTABLY DEFINING THE X-RAY BEAM, THE UPPER SET COMPRISING TWO PAIRS OF OPPOSED PLATES, THE PLATES OF EACH PAIR BEING ADJUSTABLE AT RIGHT ANGLES TO THE PLATES OF THE OTHER PAIR AND ONE SAID PAIR BEING POSITIONED ABOVE THE OTHER SAID PAIR, AN ADJUSTABLE FILTER ASSEMBLY COMPRISING A FILTER PLATE, MEANS PIVOTALLY MOUNTING THE SAID FILTER PLATE BETWEEN THE TWO SAID PAIRS OF UPPER COLLIMATING ELEMENTS AND FOR SWINGING MOVEMENT INTO AND OUT OF THE BEAM PATH DEFINED BY THE SAID ELEMENTS.

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