Damped geophone

Claim 2

In an electromagnetic geophone including a cylindrical casing, an annular coil-mass assembly in said casing, a cylindrical permanent magnet assembly in the bore of said coilmass assembly, and a spring suspension system for resiliently mounting one of said assemblies for axial movement relative the other of said assemblies, said system comprising; a pair of horizontal spring spiders for coaxially maintaining one assembly relative to the other assembly, said horizontal spiders exerting negligible restoring forces in a vertical direction, and spring means elastically supporting for reciprocating axial movement the weight of said one assembly.

Claim 3

In an electromagnetic geophone responsive to mechanical vibrations and generating an electric signal, the geophone including a housing, a coil-mass assembly having an axial bore, a permanent-mass assembly concentrically mounted inside said bore, a sPring suspension system for resiliently mounting one of said assemblies on the other assembly to reciprocally move in an axial direction, a pair of output terminals electrically connected to said coil-mass assembly to receive said electrical signal, said spring suspension system comprising: an upper horizontal spring spider engaging said one assembly for concentrically maintaining in non-weight supporting relationship the upper end of said one assembly relative to said other assembly, a bottom horizontal spring spider engaging the lower end of said one assembly for concentrically maintaining in non-weight supporting relationship the lower end of said one assembly relative to said other assembly, and a single helical spring for supporting substantially the entire mass of said one assembly and maintaining it in a desired axial position relative to said other assembly, said helical spring being adapted to linearly and reciprocally move in an axial direction when said housing becomes subjected to said mechanical vibrations.

Claim 4

In an electromagnetic geophone responsive to mechanical vibrations and generating an electric signal, the geophone including a housing, a coil-mass assembly having an axial bore, a permanent-mass assembly concentrically mounted inside said bore, a sPring suspension system for resiliently mounting one of said assemblies on the other assembly to reciprocally move in an axial direction, a pair of output terminals electrically connected to said coil-mass assembly to receive said electrical signal, said spring suspension system comprising: an upper horizontal spring spider engaging said one assembly for concentrically maintaining in non-weight supporting relationship the upper end of said one assembly relative to said other assembly, a bottom horizontal spring spider engaging the lower end of said one assembly for concentrically maintaining in non-weight supporting relationship the lower end of said one assembly relative to said other assembly, and a single helical spring for supporting substantially the entire mass of said one assembly and maintaining it in a desired axial position relative to said other assembly, said helical spring being adapted to linearly and reciprocally move in an axial direction when said housing becomes subjected to said mechanical vibrations.

Claim 5

The geophone of claim 2 wherein each spring spider includes a peripheral annular portion in engagement with said other assembly, a central annular portion in engagement with said one assembly, and a plurality of spider arms interlinking said peripheral and central annular portions.

Claim 6

The geophone of claim 3 wherein the physical size and spring characteristics of each spring spider are substantially identical whereby both spiders effectively produce matched horizontal restraining forces and negligible vertical restraining forces on said one assembly.

Claim 7

The geophone of claim 4 wherein said helical spring functions as a compression spring under static load of said one assembly.

Claim 8

The geophone of claim 5 wherein said helical spring has a conical configuration.

Claim 9

The geophone of claim 5 wherein said housing is substantially completely filled with a damping liquid.

Claim 10

The geophone of claim 7 wherein the mass ratio between said coil-mass assembly and said permanent magnet assembly is greater than 20 percent.

Claim 11

In a geophone comprising first and second relatively movable assemblies providing an output electric signal upon their relative motion, said first assembly being annular and said second assembly positioned in the bore of said first assembly, a spring suspension system resiliently suspending one of said assemblies for movement relative to the other in a direction generally parallel to the longitudinal axis of the bore in said first assembly, said spring system comprising: a top and bottom spring spider, each spider having a central annular portion and an outer annular portion connected together by a plurality of spring arms, said outer and central portions being connected to the first and second assemblies, respectively, said spider springs suspending said one assembly for movement relative to the other in a direction generally perpendicular to said longitudinal axis, and linear spring means elastically suspending said one assembly for movement relative to the other in a direction generally parallel to said longitudinal axis.

Claim 12

In a geophone comprising first and second relatively movable assemblies providing an output electric signal upon their relative motion, said first assembly being annular and said second assembly positioned in the bore of said first assembly, a spring suspension system resiliently suspending one of said assemblies for movement relative to the other in a direction generally parallel to the longitudinal axis of the bore in said first assembly, said spring system comprising: a top and bottom spring spider, each spider having a central annular portion and an outer annular portion connected together by a plurality of spring arms, said outer and central portions being connected to the first and second assemblies, respectively, said spider springs suspending said one assembly for movement relative to the other in a direction generally perpendicular to said longitudinal axis, and linear spring means elastically suspending said one assembly for movement relative to the other in a direction generally parallel to said longitudinal axis.

Claim 13

The geophone of claim 9 wherein said arms and said annular portions of each spider being preformed to substantially lie in a single plane.

Claim 14

In an electromagnetic geophone comprising an annular coil-mass assembly, a permanent magnet assembly located in the bore of said coil-mass assembly, and a spring suspension system for supporting the coil-mass assembly for movement relative to the permanent magnetic assembly, in a direction parallel to the longitudinal axis of said bore, said system comprising: two spring spiders extending transversely to said bore and spaced apart along the longitudinal axis, each spider having a central portion connected to the permanent magnet assembly, an outer portion connected to the coil-mass assembly, and a plurality of spring arms interconnecting said center and outer portions, said spring spiders having physical dimensions and spring characTeristics such that they carry no appreciable portion of the weight of said coil-mass assembly, and spring means elastically supporting said coil-mass assembly for movement relative to said permanent magnet assembly in a direction generally parallel to said longitudinal axis.

Claim 15

In an electromagnetic geophone comprising an annular coil-mass assembly, a permanent magnet assembly located in the bore of said coil-mass assembly, and a spring suspension system for supporting the coil-mass assembly for movement relative to the permanent magnetic assembly, in a direction parallel to the longitudinal axis of said bore, said system comprising: two spring spiders extending transversely to said bore and spaced apart along the longitudinal axis, each spider having a central portion connected to the permanent magnet assembly, an outer portion connected to the coil-mass assembly, and a plurality of spring arms interconnecting said center and outer portions, said spring spiders having physical dimensions and spring characTeristics such that they carry no appreciable portion of the weight of said coil-mass assembly, and spring means elastically supporting said coil-mass assembly for movement relative to said permanent magnet assembly in a direction generally parallel to said longitudinal axis.

Claim 16

The structure of claim 11 wherein said geophone is filled with a damping liquid.

Claim 17

The structure of claim 12 wherein said spring means is a helical spring.

Claim 18

The structure of claim 13 wherein said helical spring has an inverted conical configuration.

Claim 19

The structure of claim 13 wherein said helical spring has a conical configuration.

Claim 20

In an electromagnetic geophone including a housing comprising a cylindrical coil-mass assembly having a cylindrical bore therethrough, a permanent magnet assembly positioned in said bore and a spring suspension system for aligning and supporting the weight of the coil-mass assembly for movement relative to said permanent magnet assembly, said suspension comprising: two substantially horizontal spring-spiders, and one helical vertical spring, said spiders extending transversely to said bore and being coupled to the opposite ends of said coil-mass assembly, each spider having a central portion and an outer portion connected together by a plurality of spring arms substantially lying in a horizontal plane for laterally aligning and concentrically maintaining said coil-mass assembly relative to the axis of said bore, and said vertical spring engaging the annular periphery of said coil-mass assembly thereby supporting substantially the entire weight of said coil-mass assembly and elastically maintaining the coil-mass assembly for reciprocal axial movement.

Claim 21

In an electromagnetic geophone including a housing comprising a cylindrical coil-mass assembly having a cylindrical bore therethrough, a permanent magnet assembly positioned in said bore and a spring suspension system for aligning and supporting the weight of the coil-mass assembly for movement relative to said permanent magnet assembly, said suspension comprising: two substantially horizontal spring-spiders, and one helical vertical spring, said spiders extending transversely to said bore and being coupled to the opposite ends of said coil-mass assembly, each spider having a central portion and an outer portion connected together by a plurality of spring arms substantially lying in a horizontal plane for laterally aligning and concentrically maintaining said coil-mass assembly relative to the axis of said bore, and said vertical spring engaging the annular periphery of said coil-mass assembly thereby supporting substantially the entire weight of said coil-mass assembly and elastically maintaining the coil-mass assembly for reciprocal axial movement.

Claim 22

The geophone of claim 16 wherein said helical spring has a conical configuration.

Claim 23

The geophone of claim 17 wherein said housing is filled with a damping liquid.