Abstract:
An implantable generating system includes a generator assembly configured to be positioned within a living organism for converting mechanical motion into electrical energy. A linkage assembly is configured to be positioned within the living organism for mechanically coupling the generator assembly with one or more body parts displaceable during respiratory-based diaphragm motion.

Description:
FIELD OF THE DISCLOSURE 
   This disclosure relates to electrical generation systems and, more particularly, to implantable electrical generation systems. 
   BACKGROUND 
   Medical devices are often implanted into humans and animals as a means for achieving a desired result. Examples of these implanted medical devices include: pacemakers (i.e., a device used to stimulate or regulate contractions of the heart muscle); defibrillators (i.e., a device used to counteract fibrillation of the heart muscle and restore a normal heartbeat by applying a brief electric shock); bone growth stimulation devices, pain blocking/attenuation devices, brain implant devices, and cochlear implant devices, for example. Typically, these devices are powered by an internal battery or external battery pack (i.e., a battery pack implanted within the patient but external to the medical device). 
   Unfortunately, these batteries/battery packs have a finite life span and, after a period of time, must be replaced. Regardless of the type of battery/battery pack used by the medical device, surgery is required and, for those devices that use internal batteries, device removal/replacement is also required. 
   SUMMARY OF THE DISCLOSURE 
   According to an aspect of this invention, an implantable generating system includes: a generator assembly for converting mechanical motion into electrical energy. A linkage assembly, which is mechanically coupled to the generator assembly, converts respiratory motion into mechanical motion. 
   One or more of the following features may also be included. An energy storage device (e.g., a battery or a capacitor) may be electrically coupled to the generator assembly to store the electrical energy. The generator assembly may include a rotor assembly and a stator assembly. A freewheel clutch assembly, positioned between the rotor assembly and the linkage assembly, may allow for mono-directional rotation of the rotor assembly independent of the linkage assembly. A flywheel assembly may store the rotational kinetic energy of the rotor assembly. 
   The linkage assembly, which is configured to convert respiratory motion into rotational motion of the rotor assembly, may include at least one rack gear assembly mechanically coupled on a first end to a portion of a rib cage, such that the portion of the rib cage moves in response to respiratory motion. A pinion gear assembly may be mechanically coupled to the rotor assembly, and a second end of the at least one rack gear assembly may be configured to mesh with the pinion gear assembly, such that linear movement of the rack gear assembly is converted to rotational movement of the pinion gear assembly and the rotor assembly. 
   The linkage assembly, which is configured to convert respiratory motion into rotational motion of the rotor assembly, may include a fluid-filled bladder assembly that penetrates an abdominal diaphragm, such that a first portion of the bladder assembly is positioned on a first side of the abdominal diaphragm and a second portion of the bladder assembly is positioned on a second side of the abdominal diaphragm. An impeller assembly may be positioned between the first and second portions of the bladder assembly. The impeller assembly may be mechanically coupled to the rotor assembly of the generator assembly. As the abdominal diaphragm systematically moves in response to respiratory motion, the fluid within the bladder assembly may be repeatedly displaced from one of the portions of the bladder assembly to the other portion of the bladder assembly, passing through and rotating the impeller assembly. 
   The generator assembly may include a coil assembly and magnetic core assembly axially displaceable within the coil assembly. The linkage assembly may include at least one rod assembly mechanically coupled on a first end to an abdominal diaphragm, such that the abdominal diaphragm systematically moves in response to respiratory motion. A second end of the at least one rod assembly may be mechanically coupled to the magnetic core assembly and movement of the at least one rod assembly may result in axial displacement of the magnetic core assembly within the coil assembly. The at least one rod assembly may include a magnetic coupling assembly configured to temporarily uncouple the first and second ends of the rod assembly during irregular movement of the diaphragm. 
   According to another aspect of this invention, an implantable system includes a medical device. An energy storage device, which is electrically coupled to the medical device, provides electrical energy to the medical device. An implantable generating system, which is electrically coupled to the energy storage device, converts respiratory motion into electrical energy that is provided to the energy storage device. 
   One or more of the following features may also be included. The medical device may be a pacemaker, a defibrillator, a bone growth stimulation device, or a pain attenuation device, for example. The implantable generating system may include a generator assembly having a rotor assembly and a stator assembly, and a linkage assembly, mechanically coupled to the generator assembly, for converting respiratory motion into mechanical motion. The generator assembly may include a coil assembly and magnetic core assembly axially displaceable within the coil assembly. 
   According to another aspect of this invention, a method of providing electrical energy to an implanted medical device includes rigidly affixing an implantable generating system into a breathing organism, mechanically coupling the implantable generating system to a portion of the breathing organism that exhibits respiratory motion, and electrically coupling the implantable generating system to the implanted medical device. 
   One or more of the following features may also be included. The breathing organism may be a human being or an animal, for example. The medical device may be a pacemaker, a defibrillator, a bone growth stimulation device, or a pain attenuation device, for example. The portion of the breathing organism that exhibits respiratory motion may be a portion of a rib cage or an abdominal diaphragm, for example. 
   The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the description, the drawings, and the claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagrammatic view of an implantable generation system coupled to a rib cage; 
       FIG. 2  is a more detailed view of the implantable generation system of  FIG. 1 ; 
       FIG. 3  is a diagrammatic view of a bladder-type implantable generation system; 
       FIG. 4  is a more detailed view of the bladder-type implantable generation system of  FIG. 3 ; 
       FIG. 4   a  is a more detailed view of an alternative embodiment of the bladder-type implantable generation system of  FIG. 3 ; 
       FIG. 4   b  is a cross-sectional view of the alternative embodiment of the bladder-type implantable generation system of  FIG. 4   a;    
       FIG. 5  is a diagrammatic view of an implantable generation system coupled to an abdominal diaphragm; and 
       FIG. 6  is a more detailed view of the implantable generation system of  FIG. 5 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1 , there is shown an implantable generation system  10  that includes a generator assembly  12  and a linkage assembly  14 . Implantable generation system  10  may be implanted into any breathing organism (e.g., a human being or an animal) and is typically constructed of an implantable material (e.g., surgical steel, platinum, ceramic, cobalt chromium alloy, and/or ferric magnets). Generator assembly  12  is typically an alternating current or direct current generator (to be discussed below in greater detail) that generates electrical energy that is supplied (via lead  16 ) to implanted medical device  18 . Examples of medical device  18  include a pacemaker, a defibrillator, a bone growth stimulation device, a pain attenuation device, a brain implant device, a cochlear implant device, a sphincter muscle stimulation device, for example. 
   In this embodiment, linkage assembly  14  mechanically couples generator assembly  12  to two portions  20 ,  22  of the rib cage  24  that move during respiration. Specifically, as a person breathes, their ribcage expands in the direction of arrows  26 ,  28  and when that person exhales, their rib cage contracts in the direction of arrows  30 ,  32 . Linkage  14 , which is typically pivotally connected to rib cage  24 , captures this respiratory motion and uses it to e.g., turn generator assembly  12  (which is typically rigidly coupled to the sternum  34 ). Generator assembly  12  may be fastened to sternum  34  using any traditional surgical fasteners, such as surgical adhesives, staples, or screws, for example. 
   For illustrative purposes, generator assembly  12  and linkage assembly  14  are shown as being installed on the outside of the rib cage  24 . However, generator assembly  12  and linkage assembly  14  are typically installed on the inside of rib cage  24 . 
   Referring also to  FIG. 2 , there is shown a more detailed view of implantable generation system  10 . As stated above, implantable generation system  10  is electrically coupled to medical device  18 , which typically includes an energy storage device  100 , such as a lithium ion battery. Implantable generation system  10  is typically configured to provide a low-rate charge to energy storage device  100 , thus extending the useful life of energy storage device  100 . 
   Further, a redundant battery (not shown) may be connected in series between implantable generation system  10  and energy storage device  100  of medical device  18 . This redundant battery would, in turn, provide a level of redundancy in the event that implantable generation system  10  prematurely fails. 
   Typically, generator assembly  12  is a DC-type generator that includes a rotor assembly  102  and a stator assembly  104 , such that stator assembly  104  is a compact design that utilizes permanent magnets (not shown) to generator a magnetic field. As is known in the art, when rotor assembly  102  is rotated through the magnetic field generated by the permanent magnets of stator assembly  104 , a current signal is induced in the windings (not shown) of rotor assembly  102 . Depending on whether or not the rotor assembly includes a commutator, the current signal generated may need to be rectified. Typically, the current signal is converted to a voltage signal through the charging and discharging of one or more capacitors. 
   As described above, during normal respiration, the rib cage expands and contracts, resulting in the movement of linkage assembly  14 . In this embodiment, linkage assembly  14  includes two rack gear assemblies  106 ,  108 , each of which moves in the direction of arrows  110 ,  112  (respectively). As rack gear assembly  106  moves in the direction of arrow  110 , pinion gear assembly  114  rotates in a systematic clockwise/counterclockwise fashion (as indicated by arrow  116 ). Further, as rack gear assembly  108  moves in the direction of arrow  112 , pinion gear assembly  118  rotates in a systematic clockwise/counterclockwise fashion (also as indicated by arrow  116 ). This repeated clockwise/counterclockwise rotation of pinion gear assemblies  114 ,  118  results in the clockwise/counterclockwise rotation of clutch drive shaft  120 . Typically, rack gear assemblies  106 ,  108  are constructed of a material that is rigid enough to avoid deflection and buckling when compressed, yet flexible enough so that the material can bend (i.e., wrap) around the surface of the pinion gear assembly with which it is meshing. Examples of such a material include medical nylon, low friction polyethylene, and polypropylene. 
   Typically, a freewheel clutch assembly  122  is positioned between pinion gear assemblies  114 ,  118  and generator assembly  12 . A freewheel clutch assembly is a power-transmission device that allows the drive shaft of a device (i.e., generator assembly  12 ) to continue turning in a first direction (e.g., clockwise) even when the shaft (i.e., clutch drive shaft  120 ) driving freewheel clutch assembly  122  is turning in an opposite direction (e.g., counterclockwise). Accordingly, freewheel clutch assembly  122  converts the bidirectional rotation of clutch drive shaft  120  into mono-directional rotation that turns rotor assembly  102 . A typical example of freewheel clutch assembly  122  is the type of freewheel clutch assembly utilized in a self-winding wrist watch. 
   Additionally, a flywheel assembly  124  may be positioned between pinion gear assemblies  114 ,  118  and generator assembly  12 . During operation, flywheel assembly  124  stores rotational kinetic energy so that rotor assembly  102  rotates smoothly and consistently even though the rotational energy is provided from freewheel clutch assembly  124  to rotor assembly  102  in a ratcheting fashion. 
   In addition, a step-up or step-down gear assembly (not shown) may be positioned between freewheel clutch assembly  122  and generator assembly  12  so that the rotational speed of generator assembly  12  may be increased or decreased with respect to the rotational speed of freewheel clutch assembly  122 . 
   As an alternative to the embodiment described above, freewheel clutch assembly  122  may be configured such that both inhalation and exhalation result in rotation of generator assembly  12 . 
   Referring to  FIGS. 3 and 4 , there is shown a bladder-type implantable generation system  150  in which the linkage assembly  152  includes a fluid-filled bladder assembly  154  that penetrates the abdominal diaphragm  156  of the patient. A first portion  158  of bladder assembly  154  is positioned on a first side of abdominal diaphragm  156 , and a second portion  160  of bladder assembly  154  is positioned on a second side of abdominal diaphragm  156 . Typical examples of the fluid within bladder assembly  154  include an inert gas, a saline solution, and water. An impeller assembly  162  is positioned between the first and second portions  158 ,  160  of the fluid-filled bladder assembly  154 . Typically, impeller assembly  162  is positioned proximate the portion of the abdominal diaphragm  156  through which the fluid-filled bladder assembly  154  passes. 
   Referring also to  FIG. 4 , impeller assembly  162  includes one or more blade assemblies  200 ,  202 ,  204 ,  206  angled such that the passing of fluid from one of the bladder portions (e.g., portion  158 ) to the other bladder portion (e.g., portion  160 ) results in the rotation of impeller assembly  162 . Impeller assembly  162  additionally includes an impeller gear assembly  208  that meshes with gear assembly  118 . 
   Since, during normal respiratory motion, the abdominal diaphragm systematically moves in the direction of arrow  164 , the fluid within fluid-filled bladder assembly  154  is repeatedly cycled between the first and second portions  158 ,  160  of the bladder assembly  154 . Specifically, as the abdominal diaphragm move upward, the first portion  158  of fluid-filled bladder assembly  154  is compressed and fluid is evacuated from the first portion  158  to the second portion  160 . Conversely, when the abdominal diaphragm moves downward, the second portion  160  of bladder assembly  154  is compressed and fluid is evacuated from the second portion  160  to the first portion  158 . This repeated moving of the diaphragm results in the cycling of fluid from the first portion  158 , to the second portion  160 , to the first portion  158 , and so on. This, in turn, results in impeller assembly  162  cyclically rotating in the direction of arrow  210 , which in turn rotates gear assembly  118  and, therefore, generator assembly  12 . 
   As discussed above, a freewheel clutch assembly  122  is typically employed to convert the bidirectional rotation of clutch drive shaft  120  into mono-directional rotation of the rotor assembly. Further, a flywheel assembly  124  is typically positioned between gear assembly  118  and generator assembly  12  to store rotational kinetic energy. 
   In addition to the embodiment shown in  FIG. 4 , other configurations are possible. For example, impeller assembly  162 , freewheel clutch assembly  122 , flywheel assembly  124 , and generator assembly  12  may be coaxially aligned. Further, clutch drive shaft  120  may be sufficient long to allow for the positioning of impeller assembly  162  within bladder assembly  154 , the penetration of shaft  120  through bladder assembly  154 , and the positioning of freewheel clutch assembly  122 , flywheel assembly  124 , and generator assembly  12  outside of bladder assembly  154 . Alternatively still, impeller assembly  162 , freewheel clutch assembly  122 , flywheel assembly  124 , and generator assembly  12  may be a unitary structure positioned within bladder assembly  154 , such that only lead  16  penetrates bladder assembly  154 . 
   Referring to  FIGS. 4   a  &amp;  4   b , while generator assembly  12  is described above as utilizing a freewheel clutch assembly, other configurations are possible. For example, blade assemblies  200 ,  202 ,  204 ,  206  may be variable-pitch blade assemblies configured such that a change in flow direction (i.e., into bladder portion  158  versus into bladder portion  160 ) reverses the pitch of the blade assemblies. A cross-sectional view (along section line a-a of  FIG. 4   a ) of a variable-pitch blade assembly  204 ′ is shown in  FIG. 4   b . Variable pitch blade assembly  204 ′ is configured to pivot about pivot point  220 , such that the direction of pivotal rotation is controlled by the direction of fluid flow. For example, when fluid is flowing in the direction of arrow  222  (i.e., toward upper bladder portion  158 ), variable pitch blade assembly  204 ″ pivots about arc  224  toward blade position  226  (shown in phantom). Conversely, when fluid is flowing in the direction of arrow  228  (i.e., toward lower bladder portion  160 ), variable pitch blade assembly  204 ′ pivots about arc  230  toward blade position  232  (also shown in phantom). Accordingly, by reversing the blade pitch in response to a reverse in the direction of fluid flow, generator assembly  12  is allowed to rotate in the same direction regardless of whether the person is inhaling or exhaling. 
   Referring to  FIGS. 5 &amp; 6 , there is shown an alternative embodiment of the implantable generation system  250  in which the generator assembly  252  includes a coil assembly  254  and a magnetic core assembly  256  linearly displaceable along the axis  258  of coil assembly  254 . Coil assembly  252  is typically a helically wound conductor coil. As is known in the art, when magnetic core assembly  256  is linearly displaced within coil assembly  254 , a current is induced within the conductor coil. As described above, this current signal is typically processed by processing circuitry  260  (e.g., rectifier circuitry and capacitive circuitry, for example) to produce a voltage signal that is supplied (via lead  16 ) to the energy storage device  100  within medical device  18 . 
   As described above, abdominal diaphragm  156  repeatedly moves upward and downward during normal respiratory motion. Linkage assembly  262  includes a rod assembly  264  that is connected on a first end to abdominal diaphragm  156 . Rod assembly  264  may be coupled to diaphragm  156  using any means known in the art, such as sutures or surgical staples, for example. As the abdominal diaphragm moves upward and downward during normal respiratory motion, rod assembly  264  also moves upward and downward in the direction of arrow  266 . The second end of rod assembly  264  is coupled to the magnetic core  256  of generator assembly  252 . Accordingly, during normal repository motion, magnetic core assembly  256  moves upward and downward within coil assembly  254 , resulting in the generation of a voltage signal that is supplied to medical device  18 . 
   Since abdominal diaphragm  156  may move violently (i.e., irregularly) during certain events (e.g., hiccupping or vomiting, for example), a magnetic coupling assembly  268  allows for the temporarily uncoupling of the first end of rod assembly  264  (i.e., the end coupled to abdominal diaphragm  156 ) from the second end of the rod assembly  264  (i.e., the end coupled to magnetic core assembly  256 ). One embodiment of magnetic coupling assembly  268  may include a sleeve assembly  270 , a first magnet  272  connected to the upper portion  274  of rod assembly  264 , and a second magnet  276  connected to the lower portion  278  of rod assembly  264 . Magnets  272 ,  276  are configured so that they normally attract and contact each other. However, in the event that abdominal diaphragm  156  moves downward to an extent that exceeds the maximum distance that magnetic core assembly  256  can travel within coil assembly  254 , the two magnets  272 ,  276  separate, allowing the lower portion  278  of rod assembly  264  to travel an enhanced distance (as shown by magnet  276 ′), reducing the possibility of injury to abdominal diaphragm  156 . 
   Magnetic coupler assembly  268  may also be incorporated into the previously-described embodiments. For example, magnetic coupler assembly  268  may be incorporated into one or both rack gear assemblies  106 ,  108  (See  FIG. 2 ), thus allowing for temporary uncoupling of the generator assembly from the rib cage in the event of violent movement of the rib cage. 
   While magnetic coupler assembly  268  is described above as allowing for temporary uncoupling in the event of violent downward movement of the diaphragm, other configurations are possible. For example, magnetic coupler assembly  268  may be configured such that any violent movement (i.e., upward or downward) results in the temporary uncoupling of magnetic coupler assembly  268 . 
   While various type of implantable generation systems are described above, each of which uses a specific linkage assembly, other configurations are possible. For example, the embodiment described above that uses a rod assembly coupled to the abdominal diaphragm may be used with a generator assembly including a rotor and a stator assembly, provided the rod assembly is configured similarly to that of the rack gear assemblies described above. Further, the embodiment described above that uses rack gear assemblies coupled to a portion of the rib cage may be used with a generator assembly that includes a coil assembly and a magnetic core assembly, provided the rack gear assemblies are configured similarly to that of the rod assembly described above. 
   A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. Accordingly, other implementations are within the scope of the following claims.