Earth{3 s field-sensitive magnetometer for use in compass systems having gradually converging flux collectors and being insensitive to varying ambient temperature

Claim 2

A magnetometer for sensing the horizontal component of the earth''s magnetic field comprising a pair of thin flat core leg members of permeable magnetic material extending at least in part in generally parallel, spaced-apart relationship, exciting coil means magnetically coupled to said leg members for circulating an exciting magnetic flux in instantaneously opposite directions through said core leg members, pickup coil means surrounding said core leg members, and a pair of elongated flux collectors each formed of a thin flat core member of permeable magnetic material, each of said flux collectors being connected respectively at its midpoint with adjacent ends of said leg members and extending laterally from said ends of said leg members in generally overlying relationship, and said collectors being closely spaced apart at their connections to the leg members and arranged uniformly and gradually to converge toward each other and to contact each other at the ends thereof remote from said leg members.

Claim 3

A magnetometer for sensing the horizontal component of the earth''s magnetic field comprising upper and lower, thin flat core leg members of permeable magnetic material having zones thereof extending in closely spaced, generally parallel relationship at and adjacent one end of said core leg members and spaced to an appreciably greater extent at the other end of said core leg members, an exciting core and coil structure disposed between said core leg members at the latter end and said exciting core extending normal to said core leg members, a pickup coil surrounding the closely spaced zones of the core leg members, upper and lower elongated aRcuate flux collectors each formed of a thin flat core member of permeable magnetic material connected at their midpoints to and extending laterally from the closely spaced ends of said core leg members, the upper collector lying contiguous to and in contact with the lower surface of the upper core leg member and the lower collector lying contiguous to and in contact with the upper surface of the lower core leg member, said collectors being closely spaced apart at their connections to the leg members and arranged uniformly and gradually to converge toward each other and to contact each other at the ends thereof remote from said leg members.

Claim 4

A magnetometer for sensing the horizontal component of the earth''s magnetic field comprising upper and lower, thin flat core leg members of permeable magnetic material having zones thereof extending in closely spaced, generally parallel relationship at and adjacent one end of said core leg members and spaced to an appreciably greater extent at the other end of said core leg members, an exciting core and coil structure disposed between said core leg members at the latter end and said exciting core extending normal to said core leg members, a pickup coil surrounding the closely spaced zones of the core leg members, upper and lower elongated aRcuate flux collectors each formed of a thin flat core member of permeable magnetic material connected at their midpoints to and extending laterally from the closely spaced ends of said core leg members, the upper collector lying contiguous to and in contact with the lower surface of the upper core leg member and the lower collector lying contiguous to and in contact with the upper surface of the lower core leg member, said collectors being closely spaced apart at their connections to the leg members and arranged uniformly and gradually to converge toward each other and to contact each other at the ends thereof remote from said leg members.

Claim 5

The combination recited in claim 2 together with a nonmagnetic, electrically insulating base support for said core and coil structure, said base being contoured so that said core and coil structure may be secured firmly thereagainst and nonmagnetic fastening means for securing said core structure to the base at a plurality of spaced points, the magnetic core members and said base and fastening means being formed of different materials but said materials having values of temperature coefficients of expansion of substantially the same order of magnitude and correlated to minimize temperature variation effects on the performance of said magnetometer.

Claim 6

A magnetometer for sensing the horizontal components of the earth''s magnetic field comprising a core and coil structure including three radially extending, equiangularly spaced core legs, each leg including an upper and lower, generally parallely extending core leg member of permeable magnetic material relatively closely spaced at the outer ends thereof and spaced to an appreciably greater extent as the inner ends thereof, an exciting core and coil structure disposed between and extending normal to said core leg members at the inner ends thereof for simultaneously passing an exciting flux through all three legs, pickup coils surrounding the more closely spaced zones of the core leg members respectively of each core leg, said pickup coils being connected together in multicircuit fashion, and upper and lower elongated arcuate flux collectors each formed of a thin flat core member of permeable magnetic material connected at their midpoints to and extending laterally from the outer end of each core leg member, said collectors being closely spaced apart at their connections to the leg members and arranged uniformly and gradually to converge toward each other and to contact each other at the ends thereof remote from said leg members.

Claim 7

A magnetometer for sensing the horizontal components of the earth''s magnetic field comprising a core and coil structure including three radially extending, equiangularly spaced core legs, each leg including an upper and lower, generally parallely extending core leg member of permeable magnetic material relatively closely spaced at the outer ends thereof and spaced to an appreciably greater extent as the inner ends thereof, an exciting core and coil structure disposed between and extending normal to said core leg members at the inner ends thereof for simultaneously passing an exciting flux through all three legs, pickup coils surrounding the more closely spaced zones of the core leg members respectively of each core leg, said pickup coils being connected together in multicircuit fashion, and upper and lower elongated arcuate flux collectors each formed of a thin flat core member of permeable magnetic material connected at their midpoints to and extending laterally from the outer end of each core leg member, said collectors being closely spaced apart at their connections to the leg members and arranged uniformly and gradually to converge toward each other and to contact each other at the ends thereof remote from said leg members.

Claim 8

The magnetometer recited in claim 4 in which the upper collector lies contiguous to and in contact with the lower surface of the upper core leg member and the lower collector lies contiguous to and in contact with the upper surface of the lower core leg member.

Claim 9

The combination recited in claim 4 together with a nonmagnetic, electrically insulating base support for said core and coil structure, said base being contoured so that said core and coil structure may be secured firmly thereagainst, and nonmagnetic fastening means for securing said core structure to the base at a plurality of spaced points, the magnetic core members and said base and fastening means being formed of different materials but said materials having temperature coefficients of expansion of substantially the same order of magnitude.

Claim 10

A magnetometer for sensing the horizontal components of the earth''s magnetic field comprising a core and coil structure including three radially extending, equiangularly spaced core legs, each leg including an upper and lower, generally parallely extending core leg member of permeable magnetic material relatively closely spaced at the outer ends thereof and spaced to an appreciably greater extent at the inner ends thereof, an exciting core and coil structure disposed between and extending normal to said core leg members at the inner ends thereof for simultaneously passing an exciting flux through all three legs, pickup coils surRounding the more closely spaced zones of the core leg members respectively of each core leg, said pickup coils being connected together in multicircuit fashion, and upper and lower elongated arcuate flux collectors each formed of a thin flat core member of permeable magnetic material connected at their midpoints to and extending laterally from the outer end of each core leg member, the upper collector lying contiguous to and in contact with the lower surface of the upper core leg member and the lower collector lying contiguous to and in contact with the upper surface of the lower core leg member, said collectors being closely spaced apart at their connections to the leg members and arranged uniformly and gradually to converge toward each other and to contact each other at the ends thereof remote from said leg members, a nonmagnetic, electrically insulating base support for said core and coil structure, said base being contoured so that the central portion of the three-legged core may be secured in fixed position against the central portion of the base while the peripheral ends of the core legs and associated collectors may be also secured in fixed position against the base at its outer peripheral edge portions while maintaining the closely spaced zones of the radial leg members in substantially parallel planes normal to the axis of the centrally disposed exciting core and coil, a centrally disposed, nonmagnetic adjustable fastening means passing through the inner ends of the core leg members and exciting core and coil, means for securing the leg members to said base at the collector ends thereof, and means including nonmagnetic arcuate clamping members for firmly holding the free ends of the collectors in position and in mutually contacting relation, the magnetic core members and said base, adjustable fastening means and clamping members being formed of different materials but said materials having temperature coefficients of expansion of substantially the same order of magnitude whereby to maintain those core parts designed to lie horizontally in substantially horizontal positions throughout a wide range of ambient temperatures.

Claim 11

A magnetometer for sensing the horizontal components of the earth''s magnetic field comprising a core and coil structure including three radially extending, equiangularly spaced core legs, each leg including an upper and lower, generally parallely extending core leg member of permeable magnetic material relatively closely spaced at the outer ends thereof and spaced to an appreciably greater extent at the inner ends thereof, an exciting core and coil structure disposed between and extending normal to said core leg members at the inner ends thereof for simultaneously passing an exciting flux through all three legs, pickup coils surRounding the more closely spaced zones of the core leg members respectively of each core leg, said pickup coils being connected together in multicircuit fashion, and upper and lower elongated arcuate flux collectors each formed of a thin flat core member of permeable magnetic material connected at their midpoints to and extending laterally from the outer end of each core leg member, the upper collector lying contiguous to and in contact with the lower surface of the upper core leg member and the lower collector lying contiguous to and in contact with the upper surface of the lower core leg member, said collectors being closely spaced apart at their connections to the leg members and arranged uniformly and gradually to converge toward each other and to contact each other at the ends thereof remote from said leg members, a nonmagnetic, electrically insulating base support for said core and coil structure, said base being contoured so that the central portion of the three-legged core may be secured in fixed position against the central portion of the base while the peripheral ends of the core legs and associated collectors may be also secured in fixed position against the base at its outer peripheral edge portions while maintaining the closely spaced zones of the radial leg members in substantially parallel planes normal to the axis of the centrally disposed exciting core and coil, a centrally disposed, nonmagnetic adjustable fastening means passing through the inner ends of the core leg members and exciting core and coil, means for securing the leg members to said base at the collector ends thereof, and means including nonmagnetic arcuate clamping members for firmly holding the free ends of the collectors in position and in mutually contacting relation, the magnetic core members and said base, adjustable fastening means and clamping members being formed of different materials but said materials having temperature coefficients of expansion of substantially the same order of magnitude whereby to maintain those core parts designed to lie horizontally in substantially horizontal positions throughout a wide range of ambient temperatures.