CN2733380Y - Broad band feedback type seismometer - Google Patents

Abstract

The utility model relates to a wide-band feedback-type seismometer which comprises three directional geophones, an instrument casing and an external cable wire, wherein output and input conducting wires of the three directional geophones are connected with an input/output signal socket at the top of a large upright post through a plug-in piece on the large upright post on the center of a base; each directional geophone comprises an east-west horizontal geophone, a south-north horizontal geophone and a vertical geophone, wherein the east-west horizontal geophone, the south-north horizontal geophone and the vertical geophone are fixed to the base; two horizontal geophones are arranged on a horizontal plane by that central axial lines are in 90 DEG; a circuit board is arranged on a hollow upright post and is positioned above the three directional geophones; a feedback circuit is connected with a geophone coil and the output/input signal socket at the top of the upright post pass through a soft conducting wire. Inertia pendulums of the horizontal geophones can bear large pulling force, shearing force, certain pressure and high fatigue strength and have good property of return zero; a vertical directional geophone uses a hanging mode of a leaf spring, improving the work stability of pendulums, and enhancing the parasitic resonance frequency of the directional geophone.

Description

Broadband reaction type seismometer

Technical field

The utility model relates to a kind of seismological observation instrument, specifically, relates to a kind of strong earthquake far away that is used for observing, and promptly writes down the seismic event frequency band range in 20Hz-20 second, and epicentral distance is the broadband reaction type seismometer of the distant shock more than 1000 kilometers.

Background technology

Before 1973, the broadband seismograph of China's seismic network equipment is the basic formula optical recording instrument of USSR (Union of Soviet Socialist Republics) development basically, and bandwidth was by 0.1 second---12.5 seconds, the enlargement ratio that writes down displacement usually was about 1500 times.After 1973, China's seismic network has been equipped the DK-1 molded breadth frequency band seismograph by the development and production of 581 factories successively, pen is painted the five-way trace record, have three-component thousand times of level records and twice level to hundred times of level records, bandwidth was at 0.05 second-15 seconds, instrument removes can cover basic formula frequency band by letter, can replace 513 type intermediate strong motion instruments again.

Approximately since the seventies in 20th century, people introduce seismologic record with electrical feedback technology and digitizing technique gradually, thereby widen the frequency span (promptly can record simultaneously the very low and very high ground motion of frequency of frequency) of seismologic record, enlarge the dynamic range (promptly simultaneously can record very faint and very strong ground motion) of seismologic record.The realization of broadband seismic observation makes the seismologist study earthquake in a frequency band range than broad; The realization of big dynamic seismological observation might directly closely be observed the seismologist in the very near place of distance earthquake to earthquake.

The nineties, China Seismology Bureau's geophysics was born the construction of volcanic region earthquake mobile observation platform net, improved raising on the basis of former BDK-1 molded breadth frequency band seismometer, and was fixed to the portable broadband seismometer of BDK-2 type.Subsequently, the trial-production and produce the FBS-3 broadband seismometer on of port shake company with the basis, more than two kinds of instruments all be that pendulum with 2 seconds original natural vibration periods expands to 20 seconds through electrical feedback, its frequency band is 20Hz to 20 second.The structure hang of pendulum is basic identical.

More than two kinds of swinging hanging mode and structural designs that known broadband seismometer adopts, make the serviceability instability of seismometer.

The utility model content

The purpose of this utility model provides wide, the highly sensitive broadband reaction type seismometer of a kind of frequency band range.

Broadband reaction type seismometer described in the utility model comprises three-component geophone, tool housing, external cable line.Described tool housing comprises base), outer cover and handle, described outer cover covers three-component geophone and drops on the base, three branches are connected by the input/output signal socket of the plug-in unit on the big column that is installed in the base center with big column top to the output input lead of geophone, the input/output signal socket is positioned at the outer cover outside, described three-component geophone comprises the horizontal geophone of East and West direction, the horizontal geophone in north-south with vertical to geophone, when two horizontal geophones are placed, central axis becomes 90 ° on surface level, the three is fixed on the base, described wiring board is installed on the hollow column, be positioned at the top of three-component geophone, feedback line links to each other with the output input signal socket at geophone coil and column top with flexible wire by gold-plated needle-like edge connector.

A direction pilot hole is left in described base side, and spirit bubble is housed, and the stone bolt of three level-ofves evenly is installed to branch on its lower surface, on the pressure ring of outer cover handle is installed.

Horizontal geophone in described north-south and the horizontal geophone of East and West direction comprise pendulum part and moving-coil transducer respectively, described moving-coil transducer comprises the work magnet steel, demarcate magnet steel, working coil and calibration coil, form independently work system and calibration system, both place in the horizontal direction in opposite directions, work magnet steel and demarcation magnet steel lay respectively at the home position of cylindrical big magnetic conductor bowl and little magnetic conductor bowl, respectively be stamped big utmost point iron, little utmost point iron on it, working coil and calibration coil are screwed on column, and working coil and calibration coil are positioned at work magnetic field and demarcate magnetic field; Described pendulum part comprises pendulum and pivot arm, support and the turning axle of pendulum is installed.

Described pivot arm is made of two blocks of pendulum side plates, two swinging racks are clamped pendulum from two ends up and down, be screwed, the horizontal level of pendulum approaches in the middle of the swinging rack, one end of swinging rack has a root post horizontal in the centre, and the column two ends are fixed together by screw and two swinging racks, and working coil and calibration coil all are fixed on the centre position of column, two coils are coaxial, and the other end of pendulum side plate is connected with support by turning axle.

Described turning axle is to be made of two cross springs, and the cross spring connects pendulum side plate and support.

Described support by two zeroising screws and be fixed on the accent cycle and the zero point plate on, the accent cycle and zero point plate by two accent cycles nails with base by being connected.

Put part and moving-coil transducer described vertically comprising to geophone, described moving-coil transducer, described moving-coil transducer comprises big magnet steel, lower magnetic steel, working coil and calibration coil, form independently work system and calibration system, both place in vertical direction in opposite directions, work magnetic field below, demarcate magnetic field directly over work magnetic field, big magnetic conductor bowl is fixed on the big magnetic bowl seat, and on base, magnet steel frame one end is enclosed within on the big magnetic bowl big magnetic bowl seat by screw retention, be placed with little magnetic conductor bowl on the other end, little magnet steel and little utmost point iron, form and demarcate magnetic field, on the crossbeam between the biside plate that the hard-wired left and right horizontal direction of working coil and calibration coil is placed, between two magnetic fields; Described pendulum part comprises pendulum, pivot arm, turning axle, elastic cantilever and the micro-adjusting mechanism of pendulum is installed.

Described pivot arm comprises two blocks of side plates, one end of biside plate is connected with big support by turning axle, can do around turning axle and swing up and down, its other end connects two blocks of side plates by crossbeam, the working coil of described moving-coil transducer and calibration coil just are fixed on two crossbeams between the side plate, described turning axle is made up of four little reeds and two little reed fixed mounts, per two little reeds are one group and are mutually 90 ° of placements, two groups of little reeds are fixedly mounted on the two ends of two little reed fixed mounts earlier, two little reed fixed mounts are linked to each other, in the little reed fixed mount one is connected with two side plates, and another piece is connected with big support.

Described pendulum part is made up of four weights, and in four weights, first and second weight is two and is cylindrical weight, is separately fixed at the outside of two blocks of side plates; The 3rd weight is big cuboid, and it is between two blocks of side plates, and two screws are fixedly connected first and second weight and the 3rd weight and two blocks of side plates and are in the same place, and the center line of these three weights point-blank; Quadruple hammer is little cuboid, by a screw retention on big rectangular body weight hammer; Described turning axle is made up of four little reeds, and per two little reeds are one group and are mutually 90 ° of placements that two groups of little reeds are connected two side plates respectively with big support; Described elastic cantilever is made of large stretch of spring, and the one end is fixed on the stationary shaft, and the other end is fixed on the interpleural crossbeam, has hung the side plate that has pendulum and coil; Described micro-adjusting mechanism mainly refers to gear case and connected stationary shaft.

Described feedback electronics systems comprises three electronic feedback circuits, each electronic feedback circuit is connected with the coil of a geophone respectively, each electronic feedback circuit comprises the differential amplifier that adopts bilateral circuit respectively, low-pass filter and output circuit, the two ends of described working coil are connected to two "+" input ends of symmetric difference amplifier respectively, described one of them output terminal of symmetric difference amplifier arrives an end of described calibration coil through resistance parallel with one another and electric capacity negative feedback, described another output terminal of symmetric difference amplifier links to each other with the other end of described calibration coil, every group of output terminal of described symmetric difference amplifier, be connected to low-pass first order filter between the input end respectively, the signal of two output terminals of described symmetric difference amplifier is respectively through the low-pass filter of symmetry and the output circuit output of symmetry.

Broadband described in the utility model feedback seismometer, the design proposal that has adopted structural design cleverly to combine with rational electronic circuit.The inertia pendulum of horizontal vibration sensor uses the cross spring as turning axle.The cross spring is a kind of flexible bearing that does not have the machinery friction than big corner that has, and it can bear bigger pulling force, shearing force and certain pressure, and have higher fatigue strength, and time null character is good, and it is the reliable selection that the suspension of geophone coasting body connects.Use sheet spring hang vertical the branch to geophone, more increased the stability of pendulum work, also improved simultaneously this minute to spurious resonant frequencies.Therefore this seismometer has following advantage and effect:

A. adopt the electrical feedback technology, the instrument dynamic range can reach 120dB.

B. the instrument temperature good stability guarantees steady operation-10～+ 50 ℃ of scopes.

C. instrument zero is stable.Zero stability is important techniques index of broadband seismometer, and it need be verified through putting into practice work for a long time.Facts have proved that zero point adjusted once sustainable steady operation more than 1 year by DS-3KA type seismometer, is convenient to the station and safeguards.This also is the not available characteristics of domestic like product.

D. transverse vibration is less than 1%.

E. parasitic resonance＞90Hz.

F. the resistance to shock loads ability is strong, and is in light weight, and humidity resistance is good.

G. a complete set of apparatus structure design is succinct, compact, and shop characteristic is reasonable, is convenient to processing assembling and batch process, and the field is set up easy to maintenance.

Description of drawings

Fig. 1 is the structural representation of broadband reaction type seismometer described in the utility model;

Fig. 2 is the vertical view of Fig. 1;

Fig. 3 is the front view of the horizontal geophone of broadband feedback seismometer;

Fig. 4 is the vertical view of Fig. 3;

Fig. 5 is the front view of the vertical geophone of broadband feedback seismometer;

Fig. 6 is the vertical view of Fig. 5;

Fig. 7 is the block scheme of electrical feedback line system;

Fig. 8 is the circuit diagram of electrical feedback line system.

Embodiment

Referring to Fig. 1 and Fig. 2, broadband reaction type seismometer described in the utility model comprises three-component geophone, electrical feedback line system, tool housing, external cable line.Described tool housing comprises base 3, outer cover 1 and handle 4.Outer cover 1 covers three-component geophone and drops on the base 3, and three branches are connected by the input/output signal socket 65 of the plug-in unit on the big column 6 that is installed in the base center with big column top to the output input lead of geophone.Input/output signal socket 65 is in outer cover 1 outside.Described three-component geophone comprises the horizontal geophone 9 of East and West direction, the horizontal geophone 8 in north-south and vertical central axis becomes 90 ° on surface level when 7, two horizontal geophones 9,8 of geophone are placed, and the three is fixed on the base 3.Described wiring board 5 is installed on the hollow column 6, is positioned at the top of three-component geophone, and feedback line links to each other with the output input signal socket 65 at geophone coil and column top with flexible wire by gold-plated needle-like edge connector.

A direction pilot hole is left in base 3 sides, and spirit bubble 10 is housed, and the stone bolt of three level-ofves evenly is installed to branch on its lower surface.Stone bolt is by foundation bolt 75 and welding rotating disk 74 thereon, and set nut 11 compositions.When instrument was placed, the tip of three foundation bolts was dropped in the pad pin center hole, and the pad pin is placed on above the pad footmuff 76.Described outer cover 1 covers three geophones and drops on the base 3, and big nut 64 is threaded with column 6, pushes down the pressure ring 69 that is fixed on outer cover 1, and outer cover 1 is fixed on the big base.Handle 4 is installed on the pressure ring 69 of outer cover 1.

When broadband seismometer is installed, in orientation lever 2 direction of insertion pilot holes, positive dirction is also determined in orientation lever indication, as positive west to, thereby the swaying direction of determining two horizontal vibration sensor pendulums is respectively east-west direction, North and South direction, promptly picks up the seismic event of east-west direction and North and South direction.This bar is plugged when instrument is installed, and in order to determine the swaying direction of geophone, just takes off afterwards.Then, regulate and rotate three foundation bolt 75 top rotary tables 74, show that when the bubble in the spirit bubble 10 is positioned at the center base has been level, by the be locked position of three foundation bolts of set nut 11 according to the spirit bubble indication.Discharge the pendulum of three branches then respectively, pendulum can be freely swung to geophone.Make pendulum all be in null position by the zeroing screw of regulating three geophones respectively again.Cover outer cover 1 then and can connect the external belt cable plug, instrument is started working after the opening power.

Referring to Fig. 3 and Fig. 4, the horizontal geophone 8 in north-south is identical with the structure of the horizontal geophone 9 of East and West direction, is both putting position differences, and promptly both horizontal direction center lines are in 90 °.Both comprise pendulum part and moving-coil transducer respectively.Described moving-coil transducer comprises work magnet steel 32, demarcates magnet steel 23, and working coil 31 and calibration coil 25 form independently work system and calibration system, and both place (repelling each other in two magnetic fields) in the horizontal direction in opposite directions.Work magnet steel 32 and demarcation magnet steel 23 lay respectively at the home position of cylindrical big magnetic conductor bowl 33 and little magnetic conductor bowl 24, respectively are stamped big utmost point iron 34, little utmost point iron 36 on it.Working coil 31 and calibration coil 25 are screwed on column 35.Working coil 31 and calibration coil 25 are positioned at work magnetic field and demarcate magnetic field, the annulus gap that promptly forms between magnet steel and the magnetic conductor bowl.

Described pendulum part comprises pendulum 14 and pivot arm, support 17 and the turning axle of pendulum is installed.

Described pivot arm is made of two blocks of pendulum side plates 12.Two swinging racks are clamped pendulum 14 from two ends up and down, are screwed.The horizontal level of pendulum approaches in the middle of the swinging rack.One end of swinging rack has a root post 35 horizontal in the centre, and the column two ends are fixed together by screw and two swinging racks.Working coil 31 and calibration coil 25 all are fixed on the centre position of column 35, also are on the center line of two swinging racks, and guarantee that two coils are coaxial.The other end of pendulum side plate 12 is connected with support 17 by two cross springs 29.

Described turning axle is to be made of two cross springs 29.Cross spring 29 will be put side plate 12 and be connected with support 17.Connected mode is as follows: with top a slice pendulum side plate 12 is example, above a slice swinging rack and second briquetting 16 together, be screwed the latter half that clamps the cross spring; The first half of cross spring 29 is clamped by first briquetting 15 and support 17, is clamped by screw retention.

Described support 17 is fixed on accent cycle and the zero point plate 18 by two zeroising screws 26 and 28, two accent cycle nails 27 with 30 this piece transfer cycle and zero point plate 18 be connected with base 3.

Pendulum 14 is to hammer nut 13 positioning and fixing into shape with the lock on the lock hammer support 21 in transportation, opens during work again.

Referring to Fig. 5 and Fig. 6, put part and moving-coil transducer described vertically comprising to geophone.Described moving-coil transducer is formed identical with the moving-coil transducer of horizontal geophone.The modes of emplacement of just working magnetic field and demarcating magnetic field is that horizontal direction is placed (repelling each other in two magnetic fields) in opposite directions in horizontal vibration sensor, and in vertically their placements in opposite directions in vertical direction in geophone, magnetic field is demarcated directly over work magnetic field below in work magnetic field.Big magnetic conductor bowl 54 is fixed on the big magnetic bowl seat 56, big magnetic bowl seat 56 by screw retention on base 3 (see figure 1)s.Magnet steel frame 55 1 ends are enclosed within on the big magnetic bowl 54, are placed with little magnetic conductor bowl 41, little magnet steel 42 and little utmost point iron 37 on its other end, form to demarcate magnetic field.Magnet steel frame 55 promptly is to place the support of demarcating magnetic field, has guaranteed the spacing between two magnetic fields again.On the crossbeam 57 between the biside plate 58 that working coil 52 and calibration coil 43 hard-wired left and right horizontal directions are placed, also be between two magnetic fields simultaneously.

Described pendulum part comprises the pendulum part, pivot arm, turning axle, elastic cantilever and the micro-adjusting mechanism of pendulum is installed.

Described pivot arm comprises two blocks of side plates 58, one end of biside plate is connected with big support 50 by turning axle, can do around turning axle and swing up and down, its other end connects two blocks of side plates by crossbeam 57, and the working coil 52 of described moving-coil transducer and calibration coil 43 just are fixed on two crossbeams 57 between the side plate 58.

Described pendulum part is made up of four weights.In four weights, first and second weight 44 is two and is cylindrical weight, is separately fixed at the outside of two blocks of side plates 58; The 3rd weight 45 is big cuboid, and it is between two blocks of side plates, and two screws 60 are fixedly connected first and second weight 44 and the 3rd weight 45 and two blocks of side plates 58 and are in the same place, and the center line of these three weights point-blank; Quadruple hammer 39 is little cuboid, is fixed on above the big rectangular body weight hammer 45 by a screw 61.In order to regulate the pendulum cycle, on first and second weight 44, all leave the rib-loop through hole.

Described turning axle is made up of four little reeds 48 and two little reed fixed mounts 47.Per two little reeds are one group and are mutually 90 ° of placements that two groups of little reeds are fixedly mounted on the two ends of two little reed fixed mounts 47 earlier, and two little reed fixed mounts 47 are linked to each other.In the little reed fixed mount 47 one is connected with two side plates 58, and another piece is connected with big support 50.

Described elastic cantilever is made of large stretch of spring 46, produces recovery of elasticity moment, and the one end is fixed on the stationary shaft 51, and the other end is fixed on the crossbeam 62 of 58 of side plates, has hung the side plate 58 that has pendulum and coil.

Described micro-adjusting mechanism mainly refers to gear case 63 and connected stationary shaft 51.The accent cycle on the regulating tooth roller box and zero point screw 38, worm and gear in the gear case 63 drives stationary shaft 51 and rotates, change the radian of large stretch of spring 46, to change the pivot arm angle of inclination, thereby change vertically indication zero point to geophone (promptly before instrument work, the zero point pointer 49 being referred in scale 40 centers at zero point) and hunting period.This form can improve the instrument spurious resonant frequencies.

When there were vibrations on ground, side plate, pendulum and coil be lower swing in vertical direction, and coil just moves in magnetic field.

During the instrument carrying, there are two fixed heads 59 to be buckled in the rotating shaft terminal outside, two groups of little reeds are played spacing fixing effect, and respectively there are two miniature levers 70 that fixed head 59 is fixed on the little reed fixed mount 47 on the two ends fixed head 59, two side plate positions also are fixed simultaneously, pivot arm no longer moves, thereby avoids that reed is damaged in the transportation.

Referring to Fig. 7 and Fig. 8, in this wiring diagram, the working coil 31 of horizontal vibration sensor is designated as L1 with vertical working coil 52 systems to geophone, the calibration coil 35 of horizontal vibration sensor and vertical calibration coil 43 to geophone are united and are designated as L2.An identical electrical feedback line system is all arranged on described each geophone of three-component seismometer.Each electronic feedback circuit is connected with the coil of a geophone 1 respectively, comprise the differential amplifier 66 that adopts bilateral circuit respectively, low-pass filter 69 and output circuit 68, the two ends of described working coil L1 are connected to two "+" input ends of symmetric difference amplifier 66 respectively, described symmetric difference amplifier 66 one of them output terminal arrive the end of described calibration coil L2 through resistance R parallel with one another 1 and capacitor C 1 negative feedback, described symmetric difference amplifier 66 another output terminals link to each other with the other end of described calibration coil L2, every group of output terminal of described symmetric difference amplifier 66, be connected to low-pass first order filter between the input end respectively, the signal of two output terminals of described symmetric difference amplifier 66 is respectively through the low-pass filter 69 of symmetry and output circuit 68 outputs of symmetry.

Described low-pass first order filter is made of the first capacitor C2 and the second capacitor C3 respectively, and its capacitance values is all at 0.05 μ f---between the 0.33 μ f.

The frequency response of described seismometer frequency band front end is more than the 50Hz, and the interior unevenness of band is less than 1dB.

Geophone original natural vibration period is 1 second, expands to 20 seconds through electrical feedback, and bandwidth is 30Hz to 20 second.

The structure of this broadband feedback seismometer is different fully with domestic existing like product, and exclusive structural design makes job stability, recording frequency band scope, the aspects such as stability at zero point of this seismometer be better than other known product greatly.

Need to open outer cover before the instrument work, manual adjustments each minute, automaticity was still not high enough to the zero point and the cycle of geophone.

Claims (10)

1, broadband reaction type seismometer, comprise three-component geophone, tool housing, the external cable line, it is characterized in that described tool housing comprises base (3), outer cover (1) and handle (4), described outer cover (1) covers three-component geophone and drops on the base (3), three branches are connected by the input/output signal socket (65) of the plug-in unit on the big column (6) that is installed in the base center with big column top to the output input lead of geophone, input/output signal socket (65) is positioned at outer cover (1) outside, described three-component geophone comprises the horizontal geophone of East and West direction (9), the horizontal geophone in north-south (8) with vertical to geophone (7), two horizontal geophones (9, when 8) placing, central axis becomes 90 ° on surface level, the three is fixed on the base (3), described wiring board (5) is installed on the hollow column (6), be positioned at the top of three-component geophone, feedback line links to each other with the output input signal socket (65) at geophone coil and column top with flexible wire by gold-plated needle-like edge connector.

2, seismometer according to claim 1, it is characterized in that described base (3) side leaves a direction pilot hole, and spirit bubble (10) is housed, and the stone bolt of three level-ofves evenly is installed to branch on its lower surface, on the pressure ring (67) of outer cover (1), handle (4) is installed.

3, seismometer according to claim 1 and 2, it is characterized in that horizontal geophone in described north-south (8) and the horizontal geophone of East and West direction (9) comprise pendulum part and moving-coil transducer respectively, described moving-coil transducer comprises work magnet steel (32), demarcate magnet steel (23), working coil (31) and calibration coil (25), form independently work system and calibration system, both place in the horizontal direction in opposite directions, work magnet steel (32) and demarcation magnet steel (23) lay respectively at the home position of cylindrical big magnetic conductor bowl (33) and little magnetic conductor bowl (24), respectively be stamped big utmost point iron (34) on it, little utmost point iron (36), working coil (31) and calibration coil (25) are screwed on column (35), and working coil (31) and calibration coil (25) are positioned at work magnetic field and demarcate magnetic field; Described pendulum part comprises pendulum (14) and pivot arm, support (17) and the turning axle of pendulum is installed.

4, seismometer according to claim 3, it is characterized in that described pivot arm is made of two blocks of pendulum side plates (12), two swinging racks are clamped pendulum (14) from two ends up and down, be screwed, the horizontal level of pendulum approaches in the middle of the swinging rack, one end of swinging rack has a root post (35) horizontal in the centre, the column two ends are fixed together by screw and two swinging racks, working coil (31) and calibration coil (25) all are fixed on the centre position of column (35), two coils are coaxial, and the other end of pendulum side plate (12) is connected with support (17) by turning axle.

5, seismometer according to claim 4 is characterized in that described turning axle is to be made of two cross springs (29), and cross spring (29) connects pendulum side plate (12) and support (17).

6, seismometer according to claim 5, it is characterized in that described support (17) is fixed on accent cycle and the plate at zero point (18) by two zeroising screws (26) and (28), accent cycle and plate at zero point (18) by two accent cycles nails (27) and (29) and base (3) by being connected.

7, seismometer according to claim 6, it is characterized in that putting part and moving-coil transducer described vertically comprising to geophone, described moving-coil transducer comprises big magnet steel (53), lower magnetic steel (42), working coil (52) and calibration coil (43), form independently work system and calibration system, both place in vertical direction in opposite directions, work magnetic field below, demarcate magnetic field directly over work magnetic field, big magnetic conductor bowl (54) is fixed on the big magnetic bowl seat (56), big magnetic bowl seat (56) by screw retention on base (3), magnet steel frame (55) one ends are enclosed within on the big magnetic bowl (54), be placed with little magnetic conductor bowl (41) on the other end, little magnet steel (42) and little utmost point iron (37), form and demarcate magnetic field, on the crossbeam (57) between the biside plate (58) that the hard-wired left and right horizontal direction of working coil (52) and calibration coil (43) is placed, between two magnetic fields; Described pendulum part comprises pendulum, pivot arm, turning axle, elastic cantilever and the micro-adjusting mechanism of pendulum is installed.

8, seismometer according to claim 7, it is characterized in that described pivot arm comprises two blocks of side plates (58), one end of biside plate is connected with big support (50) by turning axle, can do around turning axle and swing up and down, its other end connects two blocks of side plates by crossbeam (57), working coil of described moving-coil transducer (52) and calibration coil (43) just are fixed on the crossbeam (57) between two blocks of side plates (58), described turning axle is made up of four little reeds (48) and two little reed fixed mounts (47), per two little reeds are one group and are mutually 90 ° of placements, two groups of little reeds are fixedly mounted on the two ends of two little reed fixed mounts (47) earlier, two little reed fixed mounts (47) are linked to each other, in the little reed fixed mount (47) one is connected with two side plates (58), and another piece is connected with big support (50).

9, seismometer according to claim 8 is characterized in that described pendulum part is made up of four weights, and in four weights, it is cylindrical weight that first and second weight (44) is two, is separately fixed at the outside of two blocks of side plates (58); The 3rd weight (45) is big cuboid, and it is between two blocks of side plates, and two screws (60) are fixedly connected first and second weight (44) and the 3rd weight (45) together with two blocks of side plates (58), and the center line of these three weights point-blank; Quadruple hammer (39) is little cuboid, is hammered into shape above (45) in big rectangular body weight by a screw retention; Described turning axle is made up of four little reeds (48), and per two little reeds are one group and are mutually 90 ° of placements that two groups of little reeds are connected two side plates (58) respectively with big support (50); Described elastic cantilever is made of large stretch of spring (46), and the one end is fixed on the stationary shaft (51), and the other end is fixed on the crossbeam (62) between side plate (58), has hung the side plate (58) that has pendulum and coil; Described micro-adjusting mechanism mainly refers to gear case (63) and connected stationary shaft (51).

10, seismometer according to claim 9, it is characterized in that described feedback electronics systems comprises three electronic feedback circuits, each electronic feedback circuit is connected with the coil of a geophone (1) respectively, each electronic feedback circuit comprises the differential amplifier (66) that adopts bilateral circuit respectively, low-pass filter (69) and output circuit (68), the two ends of described working coil (L1) are connected to two "+" input ends of symmetric difference amplifier (66) respectively, one of them output terminal of described symmetric difference amplifier (66) arrives an end of described calibration coil (L2) through resistance parallel with one another (R1) and electric capacity (C1) negative feedback, another output terminal of described symmetric difference amplifier (66) links to each other with the other end of described calibration coil (L2), every group of output terminal of described symmetric difference amplifier (66), be connected to low-pass first order filter between the input end respectively, the signal of two output terminals of described symmetric difference amplifier (66) is respectively through the low-pass filter (69) of symmetry and output circuit (68) output of symmetry.

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