Abstract:
A motion sensing transducer is disclosed that includes a case having an inner surface, a first cap that closes the case at a first end and a second cap that closes the case at a second end. The case inner surface, first cap and second cap define a space within the case. The apparatus further includes at least one inner plate member separating the space into at a first compartment and a second compartment within the case, a coil-magnet assembly that produces a signal when subjected to motion, the coil-magnet assembly disposed immediately within the case and in the first compartment, and an electronic circuit disposed within the second compartment that modifies the signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Application Ser. No. 60/810,744 filed on Jun. 2, 2006 and titled “Motion Transducer” the entire disclosure of which is hereby incorporated herein by reference. 
     
     BACKGROUND OF THE DISCLOSURE 
       [0002]    1. Technical Field 
         [0003]    The present disclosure generally relates to transducer sensors for sensing motion. 
         [0004]    2. Background Information 
         [0005]    Motion transducer sensors are used in a variety of applications. As an example, geophones are motion transducers that sense motion by suspending an inertial reference mass structure from a rigid, fixed supporting structure. Typically, the mass is a coil form suspended by springs in a magnetic field, one spring being attached at each end of the coil form. The springs position the coil form within the magnetic field so that the coil form is centered laterally and along its axis within the magnetic field. The springs also form a suspension system having a predetermined resonant frequency. In the case of geophones, the media is the earth. The same general transducer configuration may be used in any number of motion sensing applications having a measured media other than the earth. 
         [0006]    Motion transducer sensors of the coil-magnet type are also used non-seismic applications, e.g. structural measurements. A coil-magnet transducer may be fixed to a structure element using an adhesive or fasteners. 
       SUMMARY 
       [0007]    The following presents a general summary of several aspects of the disclosure in order to provide a basic understanding of at least some aspects of the disclosure. This summary is not an extensive overview of the disclosure. It is not intended to identify key or critical elements of the disclosure or to delineate the scope of the claims. The following summary merely presents some concepts of the disclosure in a general form as a prelude to the more detailed description that follows. 
         [0008]    In one non-limiting aspect, a motion transducer apparatus includes a case having an inner surface, a first cap that closes the case at a first end and a second cap that closes the case at a second end. The case inner surface, first cap and second cap define a space within the case. The apparatus further includes at least one inner plate member separating the space into at a first compartment and a second compartment within the case, a coil-magnet assembly that produces a signal when subjected to motion, the coil-magnet assembly disposed immediately within the case and in the first compartment, and an electronic circuit disposed within the second compartment that modifies the signal. 
         [0009]    Another non-limiting aspect provides a method that includes generating a signal representative of motion using a motion transducer, the motion transducer including a case having an inner surface, a first cap that closes the case at a first end, a second cap that closes the case at a second end, the case inner surface, first cap and second cap defining a space within the case, at least one inner plate member separating the space into at a first compartment and a second compartment within the case, a coil-magnet assembly that produces the signal when subjected to motion, the coil-magnet assembly disposed immediately within the case and in the first compartment. The method further includes modifying the signal using an electronic circuit disposed within the second compartment. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    For detailed understanding of the present disclosure, references should be made to the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein: 
           [0011]      FIG. 1  illustrates a rotating coil coil-magnet motion transducer having aspects of the disclosure for providing a transducer output signal representative of sensed motion; 
           [0012]      FIG. 2  illustrates aspects of the disclosure having stacked circuits within a transducer compartment for providing a transducer output signal representative of sensed motion; 
           [0013]      FIG. 3  illustrates aspects of the disclosure having vertically-arranged circuits within a transducer compartment for providing a transducer output signal representative of sensed motion; 
           [0014]      FIG. 4  illustrates multi-compartment aspects of the present disclosure with internal circuitry for providing a transducer output signal representative of sensed motion; 
           [0015]      FIG. 5  illustrates another multi-compartment aspect of the present disclosure; 
           [0016]      FIG. 6  illustrates yet another multi-compartment aspect of the present disclosure; 
           [0017]      FIG. 7  illustrates mounting and cable connector aspects of the disclosure; 
           [0018]      FIG. 8  illustrates other mounting and cable connector aspects of the disclosure; and 
           [0019]      FIG. 9  illustrates an aspect of the disclosure wherein a coil-magnet assembly includes a sleeve pole concentrating piece. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0020]      FIG. 1  illustrates a rotating coil coil-magnet motion transducer  10 . The transducer  10  includes a magnet  12  surrounded by a coil form  14 . The magnet  12  may be fixedly coupled to an inner top end plate or cap  16  and to a bottom end plate or cap  18 . The coil form  14  may include a two-piece configuration having an upper coil form  14   a  and a lower coil form  14   b  as shown or may be of a one piece construction. The coil form further includes an electrically-conductive coil winding  20 . The coil form is coupled to the magnet  12 , inner top end plate  16  and bottom end plate  18  by a pair of springs  22  to allow relative movement of the coil form and magnet. The coil form  14  and magnet  12  may be considered for the purposes of this disclosure as forming at least a portion of a coil-magnet assembly  56 . 
         [0021]    The coil-magnet assembly  56  is disposed immediately within a cylindrical steel outer case  24 . The case  24  includes a thick wall section  26 , an upper extended thin wall section  28  and a lower thin wall section  30 . The thick wall section may have a thickness selected based on the overall size and structural requirements desired for a particular transducer, and such dimensioning is within the skill of the art. The thick wall section  26  may have a thickness of about 1.0 mm to about 14 mm. The thinner wall sections  28 ,  30  may be on the order of about three-quarters down to one-quarter the thickness of the thick wall section  26  depending on particular needs and materials used. In one aspect the thin wall section is about 0.4 mm thick and the thick wall section is about 1.2 mm thick. The thicknesses and ranges provided here are not intended to limit the scope of the claims. A wall thickness or relative thickness falling outside the range specified herein is considered within the scope of the disclosure. 
         [0022]    A first case shoulder  32  is located at a junction of the upper extended thin wall section  28  and the thick wall section  26 . The inner top end plate  16  abuts the first shoulder  32 . A second case shoulder  34  is located at a junction of the lower thin wall section  30  and the thick wall section  26 . The bottom end plate  18  abuts the second case shoulder  34 . 
         [0023]    A cylindrical spacer  36 , which may be a metal or non-metal, is disposed on an inner surface  38  of the case extended thin wall section and extends from a top or outer surface  40  of the inner top end plate to a bottom or inner surface  42  of an outer top end plate or cap  44 . A distal upper end  46  of the case extended thin wall section may be crimped over the outer top end plate  44  and sealed via an elastomer seal  48  to close the upper portion of the transducer  10 . 
         [0024]    The bottom surface  42  of the outer top end plate  44 , and inner surface  50  of the cylindrical spacer and the top surface  40  of the inner top end plate form a compartment  52  within the transducer  10 . Embodiments having stacked circuits, multiple top compartments and embodiments with top and bottom compartments will be described later with respect to  FIGS. 2-4 . 
         [0025]    Still referring to  FIG. 1 , one or more electronic circuits  54  may be housed within the compartment  52 . The electronic circuits may be mounted on a circuit board as shown and may include one or more of an amplifier circuit, a filter circuit, a signal conditioning circuit, a converter circuit such as an analog-to-digital circuit and or a force feedback circuit for controlling the coil-magnet assembly. 
         [0026]    The coil form is coupled to the fixed coil-magnet assembly via the springs. When the case is coupled to a media of interest, the case and magnet will move along with movement of the media of interest. The coil form will tend to remain motionless thereby causing relative movement of the coil within the magnet magnetic field setting up an electrical current in the coils of the coil form. The electrical current is a signal produced by the coil-magnet assembly  56  that is an analog electrical signal. The electrical signal an analog signal representative of the movement of the case, and therefore the movement of the media of interest. The analog electrical signal is conducted from the coil-magnet assembly the electronic circuits  54  for filtering and conditioning and may be conducted to an analog-to-digital converter circuit to transform the analog signal to a digital signal suitable for processing by a computer or processor. The processed signals provide useful information about the sensed motion. 
         [0027]    The case  24  may be a steel case where the steel case forms a concentrator for the magnetic flux of the magnet. A pair of electrical leads exits the coil-magnet assembly compartment at an end. The analog signal is modified by the electronic circuits and is then conveyed out of the case via a terminal pass-through  60  and electrical leads or terminals  62 , which leads or terminals may be then connected to various other electronic circuits, a processor and or recorder device not shown here. 
         [0028]    Referring to  FIG. 2 , another aspect of a motion transducer  100  includes several circuits in a stacked configuration within a transducer compartment for providing a modified signal and a transducer output signal.  FIG. 2  shows stacked circuits  102  oriented substantially perpendicular to a longitudinal axis of the transducer  100 . 
         [0029]    In one aspect, the transducer  100  includes a magnet  104  surrounded by a coil form  106 . The magnet  104  may be fixedly coupled to an inner top end plate or cap  108  and to a bottom end plate or cap  110 . The coil form and magnet may be considered a coil-magnet assembly  112 , which may be substantially similar to the coil-magnet assembly described above and shown in  FIG. 1 . 
         [0030]    The coil magnet assembly  112  is disposed immediately within a case  114 . In one aspect, the case  114  comprises a cylindrical steel outer case. The case  114  includes a thick wall section  116 , an upper extended thin wall section  118  substantially similar to the wall sections described above and shown in  FIG. 1 . 
         [0031]    A top cap  124  is used to close an end section of the transducer. The top cap  124  has an inner surface  126 , the extended wall section  118  has an inner surface  122 , and the coil-magnet assembly cap  108  has an outer surface  128 . These surfaces form or define a compartment within the transducer case  114  to house the electronic circuits  102 . 
         [0032]    A cylindrical spacer  120 , which may be a metal or non-metal, may be disposed in the compartment and extend along the surface  122  of the case extended thin wall section from the coil-magnet assembly cap  108  to the top cap  124  to provide added support for the case  114  and to secure the inner cap  108 . In other aspects the thin wall section may include a support structure such as a rib structure to provide support. The case may alternatively include a groove structure to secure the inner cap  108 . Alternatively there may be no added spacer or structure to provide added support and the thin wall section may provide full support. Alternatively, the inner cap may be secured by an adhesive, by fasteners or may be friction fit into place. Similarly to the transducer described above and shown in  FIG. 1 , the case extended thin wall section may be crimped over the outer top cap  124  and sealed using an elastomer seal. 
         [0033]    Still referring to  FIG. 2 , the electronic circuits  102  are mounted on printed circuit boards oriented perpendicular to a longitudinal axis of the transducer  100 . The circuit boards are mounted in a stacked configuration. Any or all circuit boards  102  may include selected circuits for modifying a signal emanating from the coil-magnet assembly  112 . The circuits may include one or more of an amplifier circuit, a filter circuit, a signal conditioning circuit, a converter circuit such as an analog-to-digital circuit and or a force feedback circuit for controlling the coil-magnet assembly. The signal emanating from the coil-magnet assembly is an analog signal representative of the movement of the case, and therefore the movement of the media of interest to which the case is coupled. The analog signal is modified by the electronic circuits and is then conveyed out of the case via a plurality of terminals  130 , which terminals may be then connected to various other electronic circuits, a processor and or recorder device not shown here. 
         [0034]    Stacked circuits similar to the stacked circuits described above and shown in  FIG. 2  may be oriented in a vertical configuration as shown in  FIG. 3 .  FIG. 3  illustrates a transducer  200  having multiple circuit boards  202  configured in a vertical relationship and oriented substantially parallel to a longitudinal axis of the transducer  200  and within a case compartment. The circuit components may be mounted on the circuit boards on a single side or double side as shown. Although all transducer components are clearly shown in  FIG. 3 , in the interest of brevity, reference is made back to the configurations described above and shown in  FIGS. 1 and 2 . 
         [0035]      FIG. 4  illustrates a transducer  300  having multiple compartments within a transducer case  302 . In one aspect, a dividing member  304  separates an upper compartment  306  from a lower compartment  308 . A coil-magnet assembly  310  may be disposed immediately within a case wall  312 . A coil-magnet cap  414  has an outer surface  316 , a case extended wall portion  318  includes an inner surface  320 , and a transducer end cap  322  has an inner surface  324 . The surfaces  316 ,  320  and  324  define the main compartment, which is divided into the two compartments by the dividing member  304 . Each compartment may include electronic circuits for modifying the coil-magnet assembly signal to provide a transducer output signal representative of motion. 
         [0036]      FIG. 5  illustrates another multi-compartment aspect of the present disclosure. In one non-limiting aspect, a transducer  400  includes a coil-magnet assembly  402  disposed immediately within a case  404 . An inner top cap  406  is disposed within the case  404  and above the coil-magnet assembly  402 . An inner bottom cap  408  is disposed within the case  404  and below the coil-magnet assembly  402 . The case shown includes an upper extended wall section  410  and a lower extended wall section  412 . The upper extended wall section extends beyond the inner top cap  406  and is closed at an upper end by a case cap  414 . The lower extended wall section extends beyond the inner bottom cap  408  and is closed at a lower end by a second case cap  416 . 
         [0037]    In similar fashion to the transducer devices described above and shown in  FIGS. 1-4 , inner surfaces of the extended wall sections  410 ,  412 , inner surfaces of the case caps  414 ,  416 , and outer surfaces of the inner caps  406 ,  408  respectively define an upper compartment  418  and a lower compartment  420 . Electronic circuits  422  may be placed in either or both compartments for modifying a signal from the coil-magnet assembly  402 , and the modified signal may be transmitted from the transducer  400  using conductors  424  extending through one or both of the case caps  414 ,  416 . 
         [0038]      FIG. 6  illustrates yet another non-limiting example of multi-compartment aspect of the present disclosure. A transducer  500  includes a coil-magnet assembly  502  disposed immediately within a case  504 . An inner top cap  506  is disposed within the case  504  and above the coil-magnet assembly  502 . An inner bottom cap  508  is disposed within the case  504  and below the coil-magnet assembly  502 . The case shown includes an upper extended wall section  510  and a lower extended wall section  512 . The upper extended wall section extends beyond the inner top cap  506  and is closed at an upper end by a case cap  514 . The lower extended wall section extends beyond the inner bottom cap  508  and is closed at a lower end by a second case cap  516 . 
         [0039]    In similar fashion to the transducer devices described above and shown in  FIGS. 1-5 , inner surfaces of the extended wall sections  510 ,  512 , inner surfaces of the case caps  514 ,  516 , and outer surfaces of the inner caps  506 ,  508  respectively define an upper compartment  518  and a lower compartment  520 . Electronic circuits  522  may be placed in either or both compartments for modifying a signal from the coil-magnet assembly  502 , and the modified signal may be transmitted from the transducer  500  using conductors  524  extending through each of the case caps  514 ,  516 . 
         [0040]      FIGS. 7-8  illustrate non-limiting examples of mounting and cable connector aspects of the disclosure. Referring to  FIG. 7 , a transducer  700  includes a coil-magnet assembly  702  disposed immediately within a case  704 . An inner top cap  706  is disposed within the case  704  and above the coil-magnet assembly  702 . The case shown includes an upper extended wall section  710 . The upper extended wall section extends beyond the inner top cap  706  and is closed at an upper end by a case cap  714 . The lower case end is closed a second case cap  716 . 
         [0041]    In similar fashion to the transducer devices described above and shown in  FIGS. 1-4 , an inner surface of the extended wall section  710 , inner surface of the case cap  714 , and the outer surface of the inner cap  706  respectively define an upper compartment  718 . Electronic circuits  722  may be placed in the compartment  718  for modifying a signal from the coil-magnet assembly  702 , and the modified signal may be transmitted from the transducer  700  using conductors  724  extending through case cap  714 . A connector  708  may be used to connect a data cable (not separately shown) to the transducer  700 . The connector may be any suitable connector useful in connecting a data cable. As a non-limiting example, the shown connector includes a threaded connection. Other non-limiting examples are bayonet connectors, banana plugs, soldered connection and other connectors. The connector  708  is shown with an angled housing  712 . The housing may be angled or not depending on the particular application. Any suitable angle is within the scope of the disclosure. 
         [0042]    The transducer shown also includes a threaded mounting stud  720  as a non-limiting example of how the transducer  700  may be mounted on to a structure or other media of interest where motion measurements are to be made. The mounting stud may also be set at a desired angle. 
         [0043]    By way of non-limiting example,  FIG. 8  represents a transducer  800  substantially similar to the transducer  700  shown in  FIG. 7 . The transducer  800  is shown without an angled threaded connector to illustrate the ability to configure the transducer  800  for a particular application. The transducer  800  includes conductors  824  connecting to terminal conductors  808  for connecting the transducer electronic circuits to external circuits not shown here. All other components of the transducer  800  are substantially similar to the like components described above and shown in  FIG. 7 . Therefore, further description is not necessary for the transducer example of  FIG. 8 . 
         [0044]      FIG. 9  illustrates an aspect of the disclosure wherein a coil-magnet assembly includes a sleeve pole concentrating piece. Referring to  FIG. 9 , a transducer  900  includes a coil-magnet assembly  902  disposed immediately within a case  904 . The coil-magnet assembly  902  may include a sleeve member  903  made of a material suitable for concentrating the magnetic flux generated by the coil-magnet assembly  902 . In aspects, the sleeve material may be paramagnetic or ferromagnetic. 
         [0045]    An inner top cap  906  is disposed within the case  904  and above the coil-magnet assembly  902 . The case shown includes an upper extended wall section  910 . In one non-limiting aspect, the extended wall section comprises a relatively thick wall as compared to the case wall disposed about the coil-magnet assembly  902 . Reversing the relative thicknesses may affect the order of assembly, but the overall assembly and operation of the transducer is mostly unaffected by the choice regarding which wall section is thicker. 
         [0046]    In the transducer shown, the upper extended wall section extends beyond the inner top cap  906  and is closed at an upper end by a case cap  914 . The lower case end is closed a second case cap  916 . 
         [0047]    In similar fashion to the transducer devices described above and shown in  FIGS. 1-4 , an inner surface of the extended wall section  910 , inner surface of the case cap  914 , and the outer surface of the inner cap  906  respectively define an upper compartment  918 . Electronic circuits  922  may be placed in the compartment  918  for modifying a signal from the coil-magnet assembly  902 , and the modified signal may be transmitted from the transducer  900  via a connector  908 . The connector may be any suitable connector useful in connecting a data cable. As a non-limiting example, the shown connector includes a threaded connection. Other non-limiting examples are bayonet connectors, banana plugs, soldered connection and other connectors. The connector  908  is shown with a straight housing. The housing may be angled or not depending on the particular application. 
         [0048]    The transducer shown also includes a threaded mounting stud  920  as a non-limiting example of how the transducer  900  may be mounted on to a structure or other media of interest where motion measurements are to be made. The mounting stud may also be set at a desired angle. 
         [0049]    Those skilled in the art would recognize that geophones need not be formed using a mass formed by a magnet coupled to the case while the coil form is moveable with respect to the case as described and shown here. Having the magnet being moveable with respect to the case and coil form would generally accomplish the same function. 
         [0050]    The present disclosure is to be taken as illustrative rather than as limiting the scope or nature of the claims below. Numerous modifications and variations will become apparent to those skilled in the art after studying the disclosure, including use of equivalent functional and/or structural substitutes for elements described herein, use of equivalent functional couplings for couplings described herein, and/or use of equivalent functional actions for actions described herein. Such insubstantial variations are to be considered within the scope of the claims below. 
         [0051]    Given the above disclosure of general concepts and specific embodiments, the scope of protection is defined by the claims appended hereto. The issued claims are not to be taken as limiting Applicant&#39;s right to claim disclosed, but not yet literally claimed subject matter by way of one or more further applications including those filed pursuant to the laws of the United States and/or international treaty.