US3263078A

US3263078A - Automatic sample changer for x-ray diffractometer

Info

Publication number: US3263078A
Application number: US368030A
Authority: US
Inventors: William C Thackara; Iii Benjamin S Sanderson
Original assignee: Nat Lead Co
Current assignee: NL Industries Inc
Priority date: 1964-05-18
Filing date: 1964-05-18
Publication date: 1966-07-26
Anticipated expiration: 1983-07-26

Description

July 26, 1966 Filed May 18, 1964 W. C. THACKARA ETAL AUTOMATIC SAMPLE CHANGER FOR X-RAY DIFFRACTOMETER D \l illllllllllll 5 Sheets-Sheet l Benjamin INVENTORS William O. Thackura S. Sondersonji AGENT July 26, 1966 W. C. THACKARA ETAL AUTOMATIC SAMPLE CHANGER FOR XRAY DIFFRACTOMETER Filed May 18, 1964 Fig. 5.

5 Sheets-Sheet 2 INVENTORS William C.Th0ck.urc| Benjamin S.Sondersoq11l AGENT July 26, 1966 w. c. THACKARA ETAL AUTOMATIC SAMPLE CHANGER FOR X-RAY DIFFRACTOMETER Filed May 18, 1964 5 Sheets-Sheet 5 INVENTORS William G. Thuckora Benjamin S. Sundersorfll AGENT O 0 S 92 E United States Patent 3,263,078 AUTOMATIC SAMPLE CHANGER FOR X-RAY DIFFRACTOMETER William C. Thackara, liselin, and Benjamin S. Sanderson III, Little Silver, N..l., assignors to National Lead Company, New York, N.Y., a corporation of New Jersey Filed May 18, 1964, Ser. No. 368,030 6 Claims. (Cl. 25051.5)

The instant invention relates, in general, to X-ray diffractometers and more especially to an automatic sample changer for transferring samples to and from the sample scanning mount of the diffractometer.

X-ray dilfractometers are designed to analyze sample materials for the presence of crystalline elements by exposing the sample to X rays which emanate from a fixed X-ray source. The term sample as used herein has reference to a material to be tested and may be a single unit material i.e. a piece of metal, or a composition of matter mounted in a sample holder. In either case the sample is held on the X-ray scanning mount of the goniometer of the diffractometer for rotation through a prescribed angle whereby the X-rays are enabled to scan the surface of the sample. With the diifractometers now in use, the samples are positioned on the X-ray scanning mount of the goniometer by hand. Consequently, when it is necessary to run a large number of samples an operator must be in attendance throughout the length of the run, and when a run is of more than a normal working day or the number of samples to be tested is large, shift operators are required.

An object, therefore, of the present invention is to provide an X-ray diifractometer with automatic sample changing means.

A further object of the invention is to provide a relatively inexpensive and dependable automatic sample changing means for an X-ray diifractometer.

Another object of the invention is to provide automatic sample changing means for an X-ray diffractometer which will not impair the intrinsic accuracy of the diffractometer goniometer, and which will operate at maximum productivity and without supervision over extended periods of time.

These and other objects, features and advantages of the invention will be described in more detail in the following specification and illustrated by the drawings in which:

FIG. 1 is a schematic side elevation of an X-ray ditfractometer showing the improved automatic sample changing means of this invention mounted thereon.

FIG. 2 is an enlarged top plan view partly in section of the sample changing device shown in FIG. 1 attached to the X-ray scanning mount 11 of the goniometer.

FIG. 3 is an enlarged side elevation, partly in section on line 3-3 of FIG. 2, of the automatic sample changing means of this invention.

FIG. 4 is an enlarged rear end elevation of the sample changing device.

FIG. 5 is an enlarged isometric view changer.

FIG. 6 is the electric circuit diagram including schematic showings of pneumatic cylinder and sample-transferring carriage.

FIG. 7 is an isometric view of a sample holder mounted on the sample-transferring carriage.

In its broadest aspect, the instant invention relates to improved auto-matic sample changing means for use with an X-ray diffractometer to the type wherein the axis of the goniometer is in a substantially horizontal plane, the sample scanning mount being coaxial with the axis of rotation of the goniometer of the diffractometer, the improved sample changer comprising essentially a frameof the sample ?atented July 26, 1966 member detachably secured to the sample scanning mount of the goniometer with the longitudinal axis of the framemem'ber coaxial therewith; a sample magazine mounted on the frame-member; a sample transferring carriage slida'bly mounted on the frame-member for longitudinal movement relative thereto and adapted to receive samples from said magazine and move said samples to and from the sample scanning mount; and carriage actuating means including electric circuitry adapted to be energized by the rotation of the goniometer for automatically moving said carriage relative to said frame-member.

Referring now to the drawings in which like members designate like parts:

FIG. 1 shows, schematically, a side elevation of an X- ray dilfractometer 10 having a goniometer provided with a sample scanning mount 11 coaxial with the axis of rotation of the goniometer to which the automatic sample changer 12 of this invention is attached. As viewed in FIG. 1 and in the rear end elevation of FIG. 4, it will be seen that the longitudinal axis of the sample changer 12 is substantially in axial alignment with the axis of rotation of the goniometer scanning mount 11. As a consequence, the weight of the sample changer 12 creates no torque forces on the gears of the goniometer. This is an important factor affecting the intrinsic accuracy of the goniometer since any counter torque produced by forces acting tangentially on the axis of rotation of the goniometer would be conducive to gear wear.

As shown in somewhat more detail in FIGS. 2 and 3, the sample scanning mount 11 is a semicylindrical metal lug projecting axially from the face of a circumferentially flanged hub 13 mounted concentrically on the axis of rotation of the goniometer, the fiat 14 of the mount 11 coinciding with the axis of rotation of the goniometer.

The sample changer 12 comprises, in the main, a metal frame-member 15 having a sample holding maga zine 16 mounted substantially vertically thereon, a sample-transferring carriage 17 slidably mounted in the framemember 15 for movement longitudinally therein to and from the sample scanning mount 11, and pneumatic means 18 adapted to be actuated by electric circuitry energized by rotation of the goniometer. In addition to these major elements of the sample changer, the carriage 17 is :provided with a pivoted spring loaded pawl 19 arranged to be actuated by movement of the carriage 17 forwardly relative to the frame-member 15 to hold a sample in firm contact with the sample scanning mount 11 during the scanning cycle of the goniometer; and to release said sample therefrom upon rearward movement of the carriage relative to said frame-member.

Turning now to the frame-member 15, the latter comprises two laterally spaced parallel legs 20-20 joined at their rear ends by a transverse strap 21. The forward ends of the legs 20-20 are joined integrally with a substantially square yoke 22 perpendicular to the horizontal plane of legs 20-20. The yoke 22 has an aperture 23 therethrough the diameter of which is only slightly larger than the diameter of the circumferentially flanged hub 13 of the goniometer whereby the yoke 22 of the frarne-member is adapted to be slipped over the hub 13 and to abut against its circumferential flange.

Suitable fastening means for detachably securing the yoke 22 of the frame-member to the hub 13 comprises two metal latch bars 2424 each having a longitudinal slot midway its length to accommodate a knurled thumbscrew 25. Each thumbscrew 25 is adapted to be engaged in a threaded aperture in the corresponding leg 20 of the frame-member for securing the corresponding latch bar 24 thereto for adjustment longitudinally thereof. Each latch bar 24 has an inwardly directed hook 26 at it forward end (see FIG. 2), corresponding to the end nearest the goniometer hub 13, adapted to be engaged behind the circumferential flange of the hub 13 to firmly secure the yoke 22 of the frame-member on the hub 13 in abutting engagement with its circumferential flange. To this end, the rear end of each latch bar 24 has a right-angle lip 27 extending inwardly beyond the rear end of the corresponding leg 20 of the frame-member and adapted to accommodate a knurled thumbscrew 28, the inner end of which bears against the rear end of the corresponding leg 20 of the frame-member. Thus, with the hooks 26-26 of the latch bars 24-24 engage behind the circumferential flange of the goniometer hub 13, by turning the thumbscrews 28-28, the yoke 22 of the frame-member can be drawn up on the hub 13 in abutting engagement with its circumferential flange after which the thumbscrews 25-25 may be tightened to secure the frame-member rigidly on the hub 13. To remove the frame-member from the goniometer hub 13, it i only necessary to release the two sets of thumbscrews. Thus, by using the above-described fastening means the frame-member 15 of the automatic sample changer may be attached to and removed from the goniometer of a conventional X-ray diffractometer without requiring any alteration of the latter and with ease and dispatch.

In order to mount the sample-transferring carriage 17 in the frame-member 15 each leg 20 of the frame-member is provided with a carriage bracket 29 substantially shaped in cross section. As shown in FIG. 4, the upper lip 30 of each carriage bracket constitutes a guide rail adapted to engage in a longitudinal guide groove 31 in the corresponding side of the carriage 17, whereby the latter is supported in the frame-member for longitudinal sliding movement to and from the sample scanning mount 11 of the goniometer. Each carriage bracket 29 is secured to its corresponding leg of the frame-member by a pair of screws 32-32; and, as shown especially well in FIGS. 2 and these same screws serve also to secure the sample magazine 16 on the frame-member. To this end, the sample magazine comprises two elongated sheet metal members 33-33 each substantially [-shaped in cross section and each provided at its lower end with a downwardly extending tab 34 adapted to extend between the inner face of the corresponding leg 20 of the framemember and the outer face of the corresponding carriage bracket 29, and to be firmly secured therebetween by the aforesaid screws 32-32. As thus assembled, the two elongated sheet metal members 33-33 form a tubular magazine substantially rectangular in cross section and extending upright substantially vertically above the horizontal plane of the frame-member. The samples 37 are adapted to be assembled in the magazine one on top of another for gravity feed to the carriage 17, as hereinafter described.

The carriage 17 comprises an elongated substantially flat metal plate 35 having longitudinal upset edges 36- 36, each of which is provided on its outer face with the aforementioned guide groove 31 for accommodating a guide rail 30 of the corresponding carriage supporting bracket. The upper face of each upset edge 36 of the carriage is cut back from its forward end to form a recessed sample supporting rail 38 terminating in a vertical shoulder 39; and a raised sample supporting rail 40 rearwardly of the shoulder 39. The purpose of this construction is shown especially well in FIG. 3. In this figure, the carriage 17 is shown in its retracted position in which position the recessed sample supporting rails 38-38 of the carriage are substantially directly beneath the magazine 16. Assuming the magazine was loaded, then the lowest sample in the magazine will be free to drop down onto the recessed supporting rails 38-38 of the carriage. In so doing, the sample will be clear of the magazine and also will seat immediately in front of the carriage shoulders 39-39. Hence, as the carriage is moved forwardly relative to the magazine the sample will be carried forwardly towards the sample scanning mount 11. Simultaneously, the next succeeding sample in the magazine will move down, by gravity feed, onto and be supported by the raised sample supporting rails 48-40 rearwardly of the shoulders 39-39 of the carriage. However, since the latter rails are at a slightly higher elevation than the recessed rails 38-38 this sample will not clear the lower end of the magazine and will be retained therein until the carriage is retracted and the sample supported on the recessed rails 38-38 has been ejected therefrom.

The ejection of a sample from the carriage is done automatically upon retraction of the carriage. To this end, each sample or sample holder 37, as shown in FIG. 7, is provided with a pair of runners 41-41, the distance between the runners being slightly greater than the distance between the sample supporting rails of the carriage. Further, the sample holders are assembled in the magazine with their runners extending downwardly and substantially parallel to the sample supporting rails of the carriage. e-nce, when a sample holder drops from the magazine onto the carriage the runners 41-41 of the sample holder straddle the sample supporting rails of the carriage and this is so both for a sample holder supported on the recessed rails 38-38 as well as on the raised rails 40-40. As pointed out above, a sample holder supported on the raised rails 40-40 of the carriage is not clear of the magazine and hence the forward ends of its runners constitute, in effect, temporary fixed abutments. It follows, therefore, that where the carriage is retracted a sample holder supported on the recessed rails 38-38 of the carriage will be brought up against these fixed abutments and as the carriage continues to move rearwardly the sample holder supported thereon will be ejected from the carriage, thereby perniitting the next sample holder to drop onto the recessed rails 38-38 of the frame-member.

As will be clear from the drawings, in its forward position the carriage supports a sample directly beneath the fiat 14 of the sample scanning mount 11 and will remain in this position throughout the X-ray scanning cycle of the goniometer. In order that the samples may be held firmly against the flat 14 of the mount throughout the scanning cycle, the carriage is provided at its forward end with a depending apron 42 having a vertical slot 43 therein in which the aforementioned pawl .19 is pivotally mounted, see FIGS. 3 and 5. The upper end of the pawl 19 is rounded and adapted to engage the underside of a sample when the latter is supported on the recessed rails 38-38 of the carriage. The lower extremity of the pawl is pivotally connected to the forward end of a spring loaded pawlactuating bar 44 which extends rearwardly through the axially aligned aperture 45 of a fixed lug 46 projecting downwardly from the underside of the carriage; and through a second axially aligned aperture 47 in the aforesaid transverse strap 21 of the frame-member. A first compression spring 48 is mounted on the pawl actuating bar 44 rearwardly of the transverse strap 21 a-nd between it and a ferrule 49 on the rear extremity Of the bar. A second compression spring 50 is mounted on the pawl actuating bar 44 between a shoulder .at the forward end thereof and the forward face of the apertured lug 46. The second compression spring 50 is adapted normally; i.e., when the carriage is retracted, to urge the pawl actuating bar 44 forwardly in which position the top of the pawl is displaced counterclockwise, as seen in FIG. 3, downwardly below the plane of reoessed sample supporting rails. As the carriage is moved forwardly relative to the framemember, the first compression spring 48 is compressed and the adjustment of the latter is such that by the time the carriage has positioned a sample beneath the flat 14 of the scanning mount 11, the pawl has been swung forwardly clockwise sufficiently to engage its upper end against the underside of the sample and hold it firmly against the flat 14 of the specimen mount. At the conclusion of the scanning cycle the carriage is automatically retracted. Immediately it starts to move rearwardly, the force of the first compression spring 48 is lessened and the force of the second compression spring 50 then acts to swing the pawl rearwardly, counter-clockwise to its normal position; i.e., out of contact with the sample which is automatically ejected from the carriage in the manner hereinabove described.

Reciprocable movement of the carriage relative to the frame-member is effected by the pneumatic means 18 operated in conjunction with electric circuitry energized by rotation of the goniometer through its scanning cycle. As shown especially well in FIG. 3, the pneumatic means 18 comprises a cylinder 51 supported from a cross bar 52 secured on the underside of the frame-member. To this end, the cross bar 52 is provided with a tapped hole midway of its length in which the forward end of the pneumatic cylinder 51 is threadedly engaged and secured by nut 53. The piston in the cylinder 51 has a rod 54 extending from the forward end thereof and pivotally connected to the apron 42 of the carriage. As is evident from FIGS. 2 and 4, the longitudinal axis of the pneumatic cylinder 51 is in the vertical plane of the longitudinal axis of the frame-member. Air is supplied to the forward and rearward ends respectively of the cylinder 51 by

air hose connections

55 and 56 from a compressed air source 57 indicated schematically in FIG. 6, which also shows the electric circuitry by which the sequence of operations of the automatic sample changing device are coordinated with rotation of the goniometer through its X-ray scanning cycle. Referring again to FIG. 6, the carriage 17 is shown schematically connected to the piston rod of the pneumatic cylinder 51 to which the

air hoses

55 and 56 are connected. The

air hoses

55 and 56 are connected, in turn, to a (four-way air valve 58 to which air is supplied under predetermined pressure from the compressed air source 57. The four-Way air valve 58 is operated by an electrically energized solenoid 59 which is an integral part of a timing relay 60 which includes the standard limit switch circuit of the diffractometer. The latter, in turn, is connected through a time delay relay 61 to a pair of microswitches 62-63 carried in a switch block 64 mounted on the shaft 65 of the conventional scan control handle (high or low angle) of the goniometer. Suitable stops 66 and 67 are fixed to the frame of the diffractometer opposite the respective microswitches 62 and 63.

The operation of the automatic sample changer is controlled by actuating the microswitchs 62 and 63. Normally, i.e., when the circuitry is de-energized, the carriage 17 will be in its forward position for holding a sample against the X-ray scanning mount 11 of the diffractometer. By referring to FIG. 6, it .will be seen that when microswitch 62 is closed by engaging it with the stop 66, the relay 60 is energized and current flows to the solenoid 59 by way of the closed time delay relay 61. When the solenoid 59 is energized it actuates 'the four-way valve 58 to cause the pneumatic means 18 to retract the sample-transferring carriage, thereby ejecting a sample from the carriage and feeding a new sample onto the carriage. At the end of its rearward travel the carriage brings up against and closes a microswitch 68, which for convenience may be fixed to the rear end of the cylinder 51 as shown in FIGS. 2 and 3, whereupon the time delay relay 61, which is normally closed, is energized and opens. As a consequence, the circuit to the solenoid 59 is broken, the flow of air to the cylinder 51 is reversed, the carriage snaps forward and the microswitch 68 is opened. The time delay relay 61 is then de-energized. The above-described sequence of operations takes place substantially instantaneously upon closing the microswitch 62. Now it will be appreciated that the goniometer shaft 65 rotates slowly and hence the microswitch 62, which is mounted on the switch block 64 keyed to the shaft 65, may still be in engagement with the stop 66 in which event the entire sequence of operations would be immediately repeated with the result that the carriage would engage in a rapid reciprocating motion which would defeat the purpose to the automatic changer. This possibility is obviated, however, by the time delay relay 61 which when de-energized by the opening of microswitch 68 does not close immediately but introduces a time delay factor during which the microswitch 62 will be moved away from the stop 66 due to the rotation of the goniometer shaft 65. Hence, when the time delay relay does close to re-establish a closed circuit to the solenoid 59 the microswitch 62 will be open, thus opening the circuit to the solenoid and hence precluding retraction. of the carriage until the end of the X-ray scanning cycle.

It is common practice in the art to scan a sample for a full cycle of the goniometer, thus obtaining two diffraction patterns per sample; or for only a half cycle, in which case only one X-ray pattern is made. To meet these requirements, the circuitry shown in FIG. 6 is provided with .a selector switch 69 which, when in its open position, permits the goniometer to rotate through a full cycle before the automatic sample changer is energized to eject a sample and feed a new sample into scanning position. To scan samples for only a half cycle, it is only necessary to close the selector switch 69 whereupon actuation of the microswitch 63 at the end of each half cycle will energize the circuitry to automatically eject a sample and transfer a new one into position for scanning.

The operation of the automatic sample changer is believed to be obvious from the foregoing description but to recapitulate briefly; assuming the magazine 16 is loaded with sample holders 37 which are to be scanned by X-ray in a full cycle of the goniometer the selector switch 69 is moved to its open position. The switch block 64 is rotated counterclockwise to engage the microswitch 62 with the stop 66 whereupon the circuitry is energized to cause the carriage 17 to retract (from its normal forward position), pick up a sample and move it into engagement with the scanning mount 11 of the diffractometer. The sample is so held by the spring loaded pawl 19 during the full cycle of the goniometer at the end of which time the microswitch 62 is again brought into contact with the stop 66 to effect ejection of the sample and to transfer a new sample into position for scanning. The changer will continue in this manner automatically feeding new samples into position on the scanning mount and ejecting those that have been scanned. If at any time it is desired to scan a sample for half a cycle then it is only necessary to close the selector switch 69.

The sample changer can thus be set to operate automatically for feeding a full magazine of samples to the X-ray diffractometer without requiring supervision. Moreover the device is of relatively simple and inexpensive construction and is so designed that it may be attached to or removed from the goniometer hub 13 of the diffractometer without necessitating any changes in the electric circuitry of the latter, nor adjustment of its 2:1 alignment ratio. Moreover sample changing is done automatically with ease and dispatch. And further since the sample changer is in axial alignment with the axis of rotation of the goniometer no torque is applied to the latter that might effect excessive gear wear and hence impair the accuracy to the diffractorneter.

The invention may be carried out in other specific Ways than those herein set forth Without departing from the spirit and essential characteristics of the invention and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

In the claims:

1. An automatic sample changer for use on and X-ray diifractometer of the type having a goniometer rotatable on a horizontal axis and provided with a sample scanning mount coaxial with the axis of rotation of said goniometer said changer comprising:

(a) a frame-member arranged to be detachably secured to said sample scanning mount coaxial with the longitudinal axis thereof,

(b) a sample transferring member mounted on said frame-member for movement longitudinally thereof to and from said sample scanning mount,

(c) a sample magazine secured to said frame-member;

and

(d) means arranged to be energized by rotation of said goniometer to automatically move said sampletransferring member to and from said sample scanning mount thereby to transfer a sample from said 'magazine to said scanning mount and to withdraw a sample therefrom, respectively.

2. An automatic sample changer for use on an X-ray diifractometer of the type having a goniometer rotatable on a horizontal axis and provided with a sample scanning mount coaxial with the axis of rotation of said goniometer said changer comprising:

(b) a sample transferring member mounted on said framemember for movement longitudinally thereof to and from said sample scanning mount,

(c) a sample magazine secured to said frame member,

(d) means arranged to be energized by rotation of said goniometer to automatically move said sample-transferring member to and from said sample scanning mount thereby to transfer a sample from said magazine to said scanning mount and to withdraw a sample therefrom, respectively; and

(e) means arranged to eject a sample from said sampletransferring member.

3. An automatic sample changer for use on an X-ray difiractometer of the type having a goniometer rotatable on a horizontal axis and provided with a sample scanning mount coaxial with the axis of rotation of said goniometer changer comprising:

() a sample magazine secured to said frame-member,

((1) means arranged to be energized by rotation of said goniometer to automatically move said sampletransferring member to and from said sample scanning mount thereby to transfer a sample from said magazine to said scanning mount and to withdraw a sample therefrom, respectively,

(e) means arranged to eject a sample from said sampletransferring member; and

(f) resilient means arranged to engage and hold a sample in firm contact with said scanning mount during the scanning cycle of said goniometer.

4. An automatic sample changer for use on an X-ray diifractometer of the type having a goniometer rotatable on a horizontal axis and provided with a sample scanning mount coaxial with the axis of rotation of said goniometer said changer comprising:

(a) a frame-member arranged to be secured to said sample scanning mount with the longitudinal axis of said frame-member substantially coaxial with the axis of rotation of said scanning mount,

(b) a sample-transferring carriage arranged to be slidably mounted on said frame-member for reciprocable movement along the longitudinal axis thereof to and from said scanning mount,

(c) a sample magazine mounted on said frame-member and arranged to support a plurality of samples for gravity feed from said magazine to said slidable carriage,

(d) carriage actuating means arranged to be energized by rotation of said goniometer to automatically move said carriage to and from said sample scanning mount thereby to transfer a sample from said magazine to said scanning mount, and to withdraw a sample from said scanning mount, respectively,

(e) resilient means mounted on said carriage and arranged to be operated by movement of said carriage forwardly, longitudinally, relative to said frame-member to engage and hold a sample on said carriage firmly in contact with said sample scanning mount during rotation of said goniometer, and to re lease said sample therefrom upon rearward movement of said carriage relative to said frame member; and

(f) means arranged to eject a sample from said carriage upon retraction of the latter from said scanning mount.

5. An automatic sample changer for use on an X-ray diffractometer of the type having a goniometer rotatable on a horizontal axis and provided with a sample scanning mount coaxial with the axis of rotation of said goniometer said changer comprising:

(b) a sample-transferring carriage arranged to be slidably mounted on said frame member for reciprocable movement along the longitudinal axis thereof to and from said scanning mount,

(d) pneumatic means for moving said sample-transferring carriage relative to said frame-member for transferring a sample from said magazine to and from said sample scanning mount;

(e) electric circuitry including a solenoid-actuated air valve connected to said pneumatic means and microswitches arranged to be actuated by rotation of said goniometer to energize the solenoid of said air valve for effecting reciprocal movement of said sampletransferring carriage to and from said sample scanning mount; and

6. An automatic sample changer for use on an X-ray difiractometer for the type having a goniometer rotatable on a horizontal axis and provided with a sample scanning mount coaxial with the axis of rotation of said goniometer said changer comprising:

(a) a frame-member,

(b) fastening means carried by said frame-member and arranged to releasably engage said sample scanning mount to secure said frame-member thereto with the longitudinal axis of said frame-member substantially coaxial with the axis of rotation of said sample scanning mount,

(c) a sample-transferring carriage,

(d) mutually engaging guide-means on said carriage and said frame-member, respectively, arranged to support said carriage on said frame-member for reciprocal movement along the longitudinal axis thereof to and from said sample scanning mount,

(e) a sample magazine on said frame-member arranged to support a plurality of samples for gravity feed from said magazine to said carriage,

(f) carriage actuating means comprising a pneumatic cylinder-and-piston assembly mounted on said framemember, and pivotal means connecting said piston to said carriage whereby by energizing said pneumatic cylinder and piston assembly said carriage is moved longitudinally relative to said frame-member to and from said sample scanning mount thereby to transfer to be engaged by a sample on carriage during rea sample from said magazine to said sample scantraction of the latter for ejecting a sample from said ning mount and to withdraw a sample from said Carriage;

Sample Scanning mount, respectively, (i) electric circuitry including a solenoid actuated air (g) a pawl pivotauy monted on Said carriage and a 5 valve connected to said pneumatic cylinder, and

spring-loaded connector fastened to said pawl and mlcmswltches arranged to j acmated y mtatlon to said frame-member, respectively, whereby said of Sald gomometer to energlze sald Solenoldpawl is actuated by movement of said carriage for- R f C't d b wardly, longitudinally, relative to said frame-member e erences l e y the Exammer to engage and hold a sample firmly in contact with 10 UNITED STATES PATENTS said sample scanning mount during rotation of said 2,347,638 4/1944 McLachlan 250--5 1.5 goniometer and to release said sample therefrom upon 3,177,360 4/ 1965 ag t a1. 25 -5 1-5 rearward movement of said carriage relative to said frameqnember RALPH G. NILSON, Primary Examiner.

1: (h) means on the samples in said magazine arranged W. F. LINDQUIST, Assistant Examiner..

Claims

1. AN AUTOMATIC SAMPLE CHANGER FOR USE ON AN X-RAY DEFRACTOMETER OF THE TYPE HAVING A GONIOMETER ROTATABLE ON A HORIZONTAL AXIS AND PROVIDED WITH A SAMPLE SCANNING MOUNT COAXIAL WITH THE AXIS OF ROTATION OF SAID GONIOMETER SAID CHANGER COMPRISING: (A) A FRAME-MEMBER ARRANGED TO BE DETACHABLY SECURED TO SAID SAMPLE SCANNING MOUNT COAXIAL WITH THE LONGITUDINAL AXIS THEREOF, (B) A SAMPLE TRANSFERRING MEMBER MOUNTED ON SAID FRAME-MEMBER FOR MOVEMENT LONGITUDINALLY THEREOF TO AND FROM SAID SAMPLE SCANNING MOUNT, (C) A SAMPLE MAGAZINE SECURED TO SAID FRAME-MEMBER; AND (D) MEANS ARRANGED TO BE ENERGIZED BY ROTATION OF SAID GONIOMETER TO AUTOMATICALLY MOVE SAID SAMPLETRANSFERRING MEMBER TO AND FROM SAID SAMPLE SCANNING MOUNT THEREBY TO TRANSFER A SAMPLE FROM SAID MAGAZINE TO SAID SCANNING MOUNT AND TO WITHDRAW A SAMPLE THEREFROM RESPECTIVELY.