US2605344A - Magnetometer head - Google Patents

Description

y 29, 1952 w. H. BRATTAIN EI'AL 2,605,344

MAGNETOMETER HEAD Filed May 11, 1944 INVENTORS WALTER h. BRATTA/IV BY NORMAN E. KLEIN MAX 5. RICHARDSON g g AT TORiE Y8 Patented July 29,1952

- E. Klein, Garden Gity, and-,Max S. Richardson. Huntington, F -N. Y., assignors to the United States of Ame.

. retary euhen'aty caas represented by the Secf Application May 11, 1944, Serial No. 535,158

This invention relates to magnetometer heads and more particularly to magnetometer heads arranged for usewith magnetic. stabilization systems of the type disclosed .in cope'nding application Serial No. 529,003, filedMarch 31,.1944, Magnetic Stabilization .System, Donald .G. C..Hare.

As disclosed in the copending case above-re- 3ferred to, a detector-magnetometer: element,

which may compriseone or more magneticstrips with appropriate coils, may be heldinalignment with a relatively uniformmagnetic field by means of orienting systemsfco'ntrolled bya pair of 'au'xil iary magnetometers, .the magnetor'neter elements of which are conveniently-arranged 'vvith' their axes mutually perpendicular-and perpendicular to the axis of the detector-magnetometer element. .Also, as disclosed therein, the auxiliary magnetometer elements are mounted on the structure supporting the detector-magnetometer element and move therewith.

In the construction of a magnetometer head meeting the requirements of the system above described, it is ordinarily desired to produce a magnetometer head having'at'once compactness and freedom from interaction between the various 1 magnetometer elements. Such interaction includes modulation of 'the output of the detectormagnetometer element by the orientor-ma'gnetometer elements and the converseefi'ect. Heretofore, such interaction has been reduced to a satisfactory amount only by providing'considerable spacing between the several magnetometer elements. Such spacing is, of course, highlyundesirable in portable magnetometers in that it increases their size and weight and multiplies the 'problems encountered in mounting'such magnetometer heads in position for operation.

In view of the above, objects of the present "invention are to provide a magnetometer head adapted for use-with magnetic-stabilization systems which may be'made more compact than those heretofore used 'without'increasing inter action between the magnetometer elements, and to provide a magnetometer heacl such that-assembly and adjustment for minimum interaction are facilitated. 1

Accordingly, it is ,ajffiture of the invention to provide a magnetometerjhead comprising paired orientor-magnetometer' elements arranged in a plane in square configurationy a detector-magnetometer with itsaxis extending through and substantially perpendicular to .the plane of the configuration substantially in the center thereof, the distance from the longitudinal center of the detector-magnetometer element to this plane being substantially. zero. g v l The above and other features :of theinvention will be pointedout in the following detailed description and in the appended claims.

In the drawing, the single figure is a perspective yiewjof a magnetometer head according tothefinvention.

As shown in'the drawing, the several magnetometer elements" are mounted on .aplate .19, which is supported by a girriloalsystem shown schematically for movement about mutually perpendicular axisv A-A' and BB'. Orientorfmagnetometers each comprising a pair of magnetometer elements control-motions of plate [El about these axes.

:Thus, magnetometer elements it and 1 4 comprisethe control portion of one orientor,,ma

netometer and control the rotation of plate It about axis B-B, while elements It and -i8 comprise the control portion of the other orientor- -magnetometer and control the rotation of plate Ill about axis A-A- LThese magnetometer .ele-

.ments are mounted in pairs on plate I!) substantially-in square configuration. As indicated in the drawing, magnetic strip members 20 of the four orientor-magnetometer elements are so mounted that they form a substantially closed magnetic path about the periphery of plate It. Thus, the magnetic circuit of each pair of the orientor-magnetometer elements is in effectprovided-with a return pathof-relatively low reluctance which substantially increases its-apparent permeability and thus its sensitivity without requiring any increase in-size. This construction .is particularly advantageous when the two ma netometers are so operated that ,the magnetic flux travels continuously around the magnetic circuit.v It will be understood, however, that the .orientoremagnetometers may be connected to 0perate otherwise and that a continuous magnetic path may not always be necessary. In any event,

the placement of the wiring to the several magnetometer elements should be such that there are no linking turns which .might introduce (undesirable interactions.

Tube 22 supports the detector-magnetometer element whichismounted therein-with the-axis of symmetry of the array in alignment with the axis of the tube, the details of the mounting depending upon the type of detector element used. The tube extends through a hole'in plate l-fl having a diameter substantially greater thanrthat of the tube and. is. supported substantiallynormally to ;.the plate bymeansof a mountingtobe described below; Forminimum-interaction, the

tube 22 must be substantially;perpendicular :to the plane of the orientor-magnetometer element array and substantiallyat thecenter thereof; .,In

addition, to achieve compactness, tub-e 22-should be'only slightly longer than the elements and-the longitudinal center of the elements :within the tube should lie in or very close to the plane of the .orientor-magnetome'ter element array. Furthermore, since the magnetic axis of amagnetometer element may not coincide exactly with the geometrical axis thereof, andsince the must provide means for varying the point at I which the axis of tube 22 intersects the plane of the orientor-magnetometer array. Means must also be provided for adjusting the relative netometer element array in respect to'the plane of the orientor-magnetometer element configurations. Either of these adjustments may be more important than the other, depending upon the type of detector-magnetometer element used.

Furthermore, means must be provided for adjusting the angular position of the detectormagnetometer element array about its axis of symmetry.

If the detector-magnetometer element array is such that it has a symmetrical magnetic field, the first described adjustment is the more important although the other two must be given some consideration. If, on the other hand, the magnetic field of the detector-magnetometer array is nonsymmetrical, the rotational adjustment becomes more important. In general, a1l three must be considered but only one will be critical for any particular type of detector magnetometer.

To provide the desired adjustments, tube 22 is supported by split bushing 24, which is clamped thereto by means of a screw 26 extending normal to and across the split portion of the bushing to a nut 21 recessed in a wall of the bushing. Bushing 24 rests on plate in and may :be clamped against the plate by means of clamp ring 28 which is drawn to plate by means of bolts 30 extendin therethrough to nuts 32. Since the opening in plate I 0 is of-greater diameter than that of tube 22, the latter may be moved laterally within a limited range. Control of such motion is by means of a pair of perpendicularly disposed lateral adjustment screws 34 and 35, which act against lateral adjustment nuts 36, mounted on plate l0. Extensions on screws 34 and 35 extend through openings in' split bushing 24 and are flared over in such a manner that the screws may rotate in respect to the bushing, but may not move axially without causing lateral movement thereof. The holes in the bushing through which the screws extend are somewhat larger in diameter than the screws, and nuts 36 are mounted on plate iii forpivotal motion, thus minimizing interaction between the two adjustments. Appropriate adjustments of screws 34 and 35 alter the point at which the axis of tube 22 intersects the plane of the orientor-magnetometer element configuration.

The two'adjustments provided by the lateral adjustment screws are substantially independent, and split bushing 24 and clamp ring 28"are so arranged that these adjustments may be made without altering the positionof the longitudinal centerof tube 22 in respect to plate 16. "After the components of the head have been assembled as shown in the drawing, adjustments are made in the following manner. Adjustments of the position of the longitudinal center of the detector-magnetometer element array in respect to plate I!) are made by loosenin screw 26 to'unclamp tube 22, and moving that tube axially uripropriate output measuring instruments, interaction between detector-magnetometer element array 22 and orientor-magnetometer elements l2 4 and M are reduced to a minimum by adjustment position of the midpoint of the detector-mag 4 are reduced a minimum y ju e t fields thereof, it is desirable that these' magnetometer elements be so mounted on plate l0 that no unbalanced forces are exerted thereon. If the strips are forced, in mounting, to assume positions other than those they would assume under their own weight on a fiat surface, the magnetic field of the orientor-magnetometer configuration is badly distorted and'interaction with another magnetometer in the same region is mcreased. Interaction so caused maybe very difficult to reduce by mechanical adjustment and is to be=avoided. Accordingly, strain in strips 20 is minimized by making plate 10 of a material at once relatively free from a tendency to warp and having a temperature coefficient of expansion similar tothat of the magnetic strips, as for example Mycalex, and providing in its surface milled grooves adapted to receive strips 20 without causing appreciable distortion thereof.

Having thus described our invention, what we claim -as new and desire to secure by Letters Patent of the United States is:

l. A magnetometer head comprising paired orientor-magnetometer elementsarranged substantially in a plane in square confi ration and connected to form a closed magnetic circuit, a detector-magnetometer element disposed within said closed magnetic circuit with its axis extending through and substantially perpendicular to said plane, means for varying the point of intersection of the axis of said detector-magnetometer element with said plane, and means for varying .the distance from the longitudinal center of said REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,417,803 Valente Da Cruz 'May 30, 1922 2,027,393 McCreary Jan. 14, 1936 2,053,154 La Pierre Sept. 1, 1936 2,373,096 Bonel1 Apr. 10, 1945 2,383,460 Purves et a1. Aug. 28, 1945

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