Abstract:
A negatively buoyed aquatic toy with a watertight body portion that contains a battery electrically connected via a controller to at least one coil. The coil is positioned relative to a magnet and the coil may be caused to oscillate by virtue of a controller defined alternating current passing through the coil. The oscillation of the coil causes movement of a tail fin that is engaged to said watertight body to cause the toy to move upwards through a body of water.

Description:
FIELD OF TECHNOLOGY 
       [0001]    The present invention relates to the field of aquatic toys and related method for driving and controlling the toy. In particular though not solely, the present invention relates to an aquatic biomimetic toy and the method for driving and controlling the biomimetic toy in a manner to imitate the toy&#39;s motion, such as an up-down traverse in a body of water, driven by the toy&#39;s tail. 
       BACKGROUND 
       [0002]    Bionics is a comprehensive “boundary science” that has been evolving since the 1960&#39;s, in which life science and engineering technique are integrated together. Machines, instruments, constructions and processes have been improved by learning, simulating, copying or repeating structures, functions, working principles and control mechanisms of a biosystem. The subject of biomimetic robots was created because it was realized that organisms had high rationality and progressiveness in respects of their structure, function execution, information processing, environmental adaptation, autonomous learning as a result of long-term natural evolution. The development of biomimetic robots was derived from the pursuit of non-structural and unknown working environments, a complicated, skilful and high-difficulty work tasks, and a goal for high accuracy, high flexibility, high reliability and high intelligence. 
       SUMMARY OF THE INVENTION 
       [0003]    The aquatic toy of the present invention offers simplicity in construction and/or may be caused to change direction and/or related method for driving and controlling the toy. 
         [0004]    In an embodiment, the present invention comprises an aquatic toy apparatus that may be fully submersible in a body of water, the apparatus comprising: 
         [0005]    a body, 
         [0006]    a propeller dependent from the body in a manner to be capable of oscillatory motion relative to the body to effect a thrust on the body in a direction to propel the toy through the body of water, wherein the body comprises:
       a) a battery,   b) a driver operatively connected to the propeller to cause the propeller to oscillate, the driver being driven by the interaction of an energizable coil and a magnet, the coil energizable by the battery,       
 
         [0009]    wherein the toy is configured to be less buoyant than water and has a centre of buoyancy spaced a distance from the centre of mass of the toy, the thrust acts parallel to a line passing through and in a direction from the centre of mass to the centre of buoyancy and is capable of being sufficient to cause the toy to move upwards towards the surface of the water. 
         [0010]    In an embodiment, the body comprises the energizable coil and the magnet. 
         [0011]    In an embodiment, the body comprises a sealed buoyant body in which the battery is located. 
         [0012]    In an embodiment, the propeller comprises a fin. 
         [0013]    In an embodiment, the propeller is engaged to the body in a manner to allow it to make a swishing like oscillatory motion relative to the body as a result of the movement of the driver. 
         [0014]    In an embodiment, the driver is pivotally mounted relative to the body and is engaged, at one side of the pivot to said propeller, and at the opposite side of said pivot and inside said body, to one of (a) said energizable coil and (b) said magnet, wherein the other of (a) said energizable coil and (b) said magnet is mounted in a manner fixed to said body in a location to allow such to operatively interact to drive said driver in at least one direction for rotation about said pivot. 
         [0015]    In an embodiment, the driver extends out of the body and is engaged to the propeller external of the body. 
         [0016]    In an embodiment, a drive control circuit is provided in said body to control the energization of said coil. 
         [0017]    In an embodiment, said body defines an enclosure, and said driver is a shaft and said propeller is fixed at or towards one end of the shaft, and one of said (a) coil or (b) magnet is engaged at or towards the other end of the shaft and inside said enclosure, wherein between said ends, said shaft passes through said buoyant body in a sealed manner so that a floating hermetic closure is formed. 
         [0018]    In an embodiment, said coil is engaged to said driver and may move in an oscillatory manner with said driver for alternating interaction with at least one magnet secured to said buoyant body. 
         [0019]    In an embodiment, said at least one magnet is one magnet that is presented with its polarity oriented towards the coil in a manner to make said magnet attract said coil when said coil is energized with a current, such that said driver is moved in one direction. 
         [0020]    In an embodiment, when said coil is energized with a reversed current, said coil is repelled by said magnet, such that said driver is moved in an opposite direction. 
         [0021]    In an embodiment, said at least one magnet is two magnets secured to said buoyant body. 
         [0022]    In an embodiment, each of said two magnets is presented with its polarity oriented towards the coil in a manner to make one magnet generate an attraction force and the other magnet generate a pushing force on said driver when the coil is energized. 
         [0023]    In an embodiment, energization is of said coil is controlled by said drive control circuit in a manner to alter the direction of current through the coil and thus the magnetic polarity of the coil. 
         [0024]    In an embodiment, said driver may be deflected by altering the current supplied to said coil, said current being current pulses that are altered by at least one of duration of said pulses, amplitude of said pulses and offsetting of said pulses, said drivers&#39; movement due to said altering of said current causing deflection of said propeller, causing said aquatic toy to turn. 
         [0025]    In an embodiment, a pair of coils is secured to said buoyant body and a magnet is carried by said driver, and an attraction force and a pushing force may be generated between each of said pair of coils and said magnet when the pair of coils is energized by an alternating current. 
         [0026]    In an embodiment, at least one additional magnet is fixed to said battery and a second coil may be energized such that the interaction force between said second coil and said at least one additional magnet drives said battery to move forward or backward so as to change the position of said battery in said buoyant body and adjust the centre of gravity of the buoyant body, such that said aquatic toy in use may move up or down dependent on the energization of said second coil. 
         [0027]    In an embodiment, an activation circuit is provided to activate the energization of the coil(s), the activation circuit selected from one of (a) a vibration switch and (b) moisture sensor and (c) terminals of a circuit or switching circuit that complete an electrical circuit via water in which said aquatic toy may be placed. 
         [0028]    In an embodiment, the propeller is in the shape of a toy tail and the body is in the shape of a toy body. 
         [0029]    In an embodiment, wherein said drive control circuit comprises a PCB, a vibration switch and at least one LED indicator light that indicates whether said aquatic toy is working or being charged. 
         [0030]    In an embodiment, said vibration switch comprises a central post and a vibration spring, wherein when vibration of said buoyant body is transmitted to said spring, the spring may swing to contact said central post when the swing exceeds a certain amplitude and accordingly an electric signal is generated to activate said drive control circuit. 
         [0031]    In an embodiment, said drive control circuit has an infrared receiving tube that may receive a remote control signal, such that the drive control circuit may execute operation corresponding to the received signal. 
         [0032]    In an embodiment, the toy is configured to be less buoyant than water and has a centre of buoyancy spaced a distance from the centre of mass of the toy to create a righting moment for said toy, the propeller positioned to be below the centre of buoyancy to effect a net thrust in a upwards direction when the toy is submersed in water. 
         [0033]    In an embodiment, the toy is configured to be less buoyant than water and has a centre of buoyancy spaced a distance from the centre of mass of the body to create a righting moment for said toy, the propeller positioned to be below the centre of buoyancy and acting on the body to effect a net thrust acting on a notional line extending between the centre of mass and the centre of buoyancy. 
         [0034]    In an embodiment, the toy is configured to be less buoyant than water and has a centre of buoyancy spaced a distance from the centre of mass of the toy to create a righting moment for said toy, the propeller positioned to be below the centre of buoyancy and acting on the body to effect a net thrust acting on and parallel a notional line extending between the centre of mass and the centre of buoyancy. 
         [0035]    In an embodiment, the toy is configured to be less buoyant than water and has a centre of buoyancy spaced a distance from the centre of mass of the toy to create a righting moment for said toy wherein the propeller is dependent from said body at a location below the centre of mass and centre of buoyancy. 
         [0036]    In an embodiment, the body is elongate and has a figurative head located opposite the propeller from the centre of mass and centre of buoyancy. 
         [0037]    In an embodiment, the toy is configured to be less buoyant than water and has a centre of buoyancy spaced a distance from the centre of mass of the toy to create a righting moment for said toy wherein the centre of buoyancy is located between the centre of mass and the figurative head. 
         [0038]    In an embodiment, the centre of mass is located between the centre of buoyancy and the propeller. 
         [0039]    In an embodiment, the body has a figurative head and the toy is configured to be less buoyant than water and has a centre of buoyancy spaced a distance from the centre of mass of the toy to create a righting moment for said toy in a manner to keep the figurative head as the upper most part of the toy went in water. 
         [0040]    In an embodiment, the body is elongate shaped and said propeller is disposed at one end of the elongate body and a figurative head is located at the opposite end of the body. 
         [0041]    In an embodiment, when the toy is submerged in water, the propeller creates thrust in a vertical direction. 
         [0042]    In an embodiment, when the toy is submerged in water, the propeller creates a net thrust in a not in a horizontal direction. 
         [0043]    In an embodiment, the aquatic toy may be fully submersible in a body of water and comprise: 
         [0044]    a body, 
         [0045]    a tail fin dependent from the body in a manner to be capable of oscillatory motion relative to the body to effect a net thrust on said body in a direction to propel the toy through the body of water, wherein the body comprises:
       a) a battery,   b) a driver operatively connected to the tail fin to cause said tail fin to oscillate, the driver being driven by the interaction of an energizable coil and a magnet, the coil energizable by said battery,       
 
         [0048]    wherein the toy is configured to be less buoyant than water and has a centre of buoyancy spaced a distance from the centre of mass of the body, the net thrust effected acts parallel to a line passing through and in a direction from the centre of mass to the centre of buoyancy and is capable of being sufficient to cause the toy to move upwards towards the surface of the water. 
         [0049]    In an embodiment, the aquatic toy apparatus may be fully submersible in a body of water and comprise: 
         [0050]    a body comprising a head, 
         [0051]    a tail fin dependent from the body in a manner to be capable of oscillatory motion relative to the body to effect a thrust on said body in a direction to propel the toy through the body of water, wherein the body comprises:
       a) a battery,   b) a driver operatively connected to the tail fin to cause said tail fin to oscillate, the driver being driven by the interaction of an energizable coil and a magnet, the coil energizable by said battery,       
 
         [0054]    wherein the toy is configured to be heavier than water and having a mass distribution to create a righting moment for said toy when submersed, and wherein the thrust is sufficient to encourage the toy, when submersed, towards the surface of the body of water. 
         [0055]    In an embodiment, the toy may be heavier than water and have a mass distribution that creates a righting moment for said toy when submersed, and wherein the thrust is sufficient to encourage the toy, when submersed, towards the surface of the body of water, head first. 
         [0056]    In an embodiment, the toy may be heavier than water and have a mass distribution that creates a righting moment for said toy when submersed, and wherein the thrust is sufficient to encourage the toy, when submersed, towards the surface of the body of water, tail trailing. 
         [0057]    In an embodiment, the fin is located to effect thrust in a direction towards the head. 
         [0058]    In an embodiment, the centre of mass and centre of buoyancy may be located intermediate the fin and the head. 
         [0059]    In an embodiment, the centre of mass and centre of buoyancy may be located on a plane or line passing through the fin and the head. 
         [0060]    In an embodiment, when the toy is in use, the head is located above the centre of buoyancy which is located above the centre of mass which is located above the fin. 
         [0061]    In an embodiment, when the fin creates net thrust on said body in direction that is coincident the line or plane passing through said centre of buoyancy and centre of mass. 
         [0062]    In an embodiment, the driver is controlled to vary the duration, amplitude, or speed of tail fin oscillation. 
         [0063]    In an embodiment, the driver is controlled to intermittently cause tail fin oscillation. 
         [0064]    In an embodiment, the driver is controlled to intermittently cause tail fin oscillation in a manner to allow the toy, from time to time, to move towards the bottom of the body of water. 
         [0065]    In an embodiment, the driver is controlled to intermittently cause tail fin oscillation in a manner to allow the toy, from time to time, to move towards the bottom of the body of water when oscillation is terminated and, from time to time, to move towards the surface of the body of water when oscillation is terminated. 
         [0066]    In an embodiment, the driver is controlled to vary the duration, amplitude, or speed of tail fin oscillation in a manner to allow the toy to alternately, sink and rise in the body of water. 
         [0067]    In an embodiment, the aquatic toy may be fully submersible in a body of water and comprise: 
         [0068]    a body, 
         [0069]    a tail fin dependent from the body in a manner to be capable of oscillatory motion relative to the body to effect a net thrust on said body in a direction to propel the toy through the body of water, wherein the body carries:
       a) a battery,   b) a driver operatively connected to the tail fin to cause said tail fin to oscillate, the driver being electrically driven by electric energy derived from said battery,       
 
         [0072]    wherein the toy is configured to have negative buoyancy with a mass distribution to create a righting moment for said toy when submersed, and 
         [0073]    wherein the net thrust is sufficient to overcome the negative buoyancy to encourage the toy, when submersed, towards the surface of the body of water. 
         [0074]    In an embodiment, the driver may be controlled to vary the duration, amplitude, or speed of tail fin oscillation. 
         [0075]    In an embodiment, the driver may be controlled to intermittently cause tail fin oscillation. 
         [0076]    In an embodiment, the driver may be controlled to intermittently cause tail fin oscillation in a manner to allow the toy, from time to time, to move towards the bottom of the body of water. 
         [0077]    In an embodiment, the driver may be controlled to intermittently cause tail fin oscillation in a manner to allow the toy, from time to time, to move towards the bottom of the body of water when oscillation is terminated and, from time to time, to move towards the surface of the body of water when oscillation is terminated. 
         [0078]    In an embodiment, the driver is controlled to vary the duration, amplitude, or speed of tail fin oscillation in a manner to allow the toy to alternately, sink and rise in the body of water. 
         [0079]    In an embodiment, the present invention comprises a negatively buoyed biomimetic toy fully submersible in water and a watertight body portion that contains a battery electrically connected via a controller to at least one coil, said coil positioned relative to at least one magnet, said coil oscillating in response to magnetic pole interactions between said at least one coil and said at least one magnet by virtue of a controller defined alternating current passing through said coil, said coil oscillation causing movement of a tail fin that is engaged to said coil and said watertight body to cause said toy to move upwards through a body of water with the tail trailing. 
         [0080]    In an embodiment, the present invention comprises an aquatic toy for use in a body of water, the toy comprising: 
         [0081]    a body, 
         [0082]    a tail fin dependent from the body in a manner to be capable of oscillatory motion relative to the body to effect a thrust on said body in a direction to propel the toy through the body of water, wherein the body comprises:
       a) a battery,   b) a driver operatively connected to the tail fin to cause said tail fin to oscillate, the driver being electrically driven by electric energy derived from said battery,       
 
         [0085]    wherein the toy is able to have any one or more of the following characteristics varied:
       (a) specific gravity for both overall positive and negative toy buoyancy   (b) centre of mass, and   (c) centre of buoyancy.       
 
         [0089]    In an embodiment, the toy may have any two or more of the following characteristics varied:
       (a) specific gravity for both overall positive and negative toy buoyancy,   (b) centre of mass, and   (c) centre of buoyancy.       
 
         [0093]    In an embodiment, the toy may have its specific gravity for both overall positive and negative toy buoyancy, and at least one of (a) centre of mass, and (b) centre of buoyancy varied. 
         [0094]    In an embodiment, the toy may moveably carry, and/or removably receive an external weight of specific gravity greater than 1. 
         [0095]    In an embodiment, the toy&#39;s specific gravity may be varied as a result of the body being changeable in volume. 
         [0096]    In an embodiment, the toy comprises an interchangeable element that may be interchanged with like elements for the purposes of varying at least one of:
       (a) specific gravity,   (b) centre of mass, and   (c) centre of buoyancy, of the toy.       
 
         [0100]    In an embodiment, the toy comprises an element of specific gravity greater than 1 capable of being received by said body (for example at a receptacle region thereof) the element allowing the specific gravity and centre of mass of the toy to be varied. 
         [0101]    In an embodiment, the toy comprises an element of specific gravity less than 1 capable of being received by said body (for example at a receptacle region thereof) the element allowing the specific gravity and centre of buoyancy of the toy to be varied. 
         [0102]    In an embodiment, the element may be received at multiple locations by the body. 
         [0103]    In an embodiment, the toy&#39;s specific gravity may be varied by varying at least one of:
       (a) overall mass by the addition or removal of mass heavier than water, and   (b) overall buoyancy by increasing or decreasing its volume.       
 
         [0106]    In an embodiment, when the toy is configured to have negative buoyancy the mass distribution of the toy is such as to create a righting moment for said toy to orient the fin to provide thrust to said body in a direction and sufficient to overcome the negative buoyancy to encourage the toy, when submersed, towards the surface of the body of water. 
         [0107]    In an embodiment, when the toy is configured to have positive buoyancy the mass distribution of the toy is such as to create a righting moment for said toy to orient the fin to provide thrust to said body in a direction and sufficient to overcome the positive buoyancy to encourage the toy, when submersed, towards the bottom of the body of water. 
         [0108]    In an embodiment, the present invention comprises an aquatic toy for use in a body of water and: 
         [0109]    a body, 
         [0110]    a tail fin dependent from the body in a manner to be capable of oscillatory motion relative to the body to effect a thrust on said body in a direction to propel the toy through the body of water, wherein the body comprises:
       a) a battery,   b) a driver operatively connected to the tail fin to cause said tail fin to oscillate, the driver being electrically driven by electric energy derived from said battery,       
 
         [0113]    an adjustable element that is or is able to be associated with the body at least one location to vary at least one of:
       (a) specific gravity for both overall positive and negative toy buoyancy,   (b) centre of mass of the toy, and   (c) centre of buoyancy of the toy.       
 
         [0117]    In an embodiment, the adjustable element may be externally associated with said body. 
         [0118]    In an embodiment, the adjustable element may be associated with said body in at least two different locations of the body. 
         [0119]    In an embodiment, the adjustable element may comprise a specific gravity greater than 1, may be less than 1, and/or may have an adjustable volume. Also in an embodiment, the adjustable element may be able to be selectively associated with said body and/or be removably associated with the body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0120]    The invention may be further described with reference to the accompanying drawings and embodiment. 
           [0121]      FIG. 1  illustrates a front view of a toy according to an embodiment of the present invention. 
           [0122]      FIG. 2  illustrates a cross-sectional rear view of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0123]      FIG. 3  illustrates a partial cross-sectional view of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0124]      FIG. 4  illustrates perspective view of a charging seat cover for use with the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0125]      FIG. 5  illustrates a perspective view of a coil bracket for use with the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0126]      FIG. 6  illustrates a schematic diagram of an optical structure of indicators for use with the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0127]      FIG. 7  illustrates a coil and magnet configuration for use with the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0128]      FIG. 8  illustrates a coil and magnet configuration for use with the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0129]      FIG. 9  illustrates a front view of the toy illustrated in  FIG. 1  according to an embodiment of the present invention toy 
           [0130]      FIG. 10  illustrates a partial plan view of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0131]      FIG. 11  illustrates a partial side view of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0132]      FIG. 12  illustrates a top view of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0133]      FIG. 13  illustrates an end view of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0134]      FIG. 14  illustrates a schematic view of the centre of mass and centre of gravity of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0135]      FIG. 15  illustrates a schematic view of the centre of mass and centre of gravity shown and thrust angles of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. with, 
           [0136]      FIG. 16  illustrates a schematic view of the centre of mass and centre of gravity shown, illustrating a righting moment of the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
           [0137]      FIG. 17  illustrates a schematic view of the gravity, buoyancy and thrust forces acting on the toy illustrated in  FIG. 1  according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0138]    Referring to  FIGS. 1 to 7 , the aquatic toy of the present invention replicates a toy in an embodiment. Herein after the toy may be referred to as a toy but other shapes and appearance figures or objects also fall within the scope of the invention. 
         [0139]    The toy comprises of a body assembly  1  and a propeller, and in an embodiment, in the form of a toy tail assembly  2 . The toy tail assembly  2  is engaged or integrally formed with the body assembly  1 . 
         [0140]    In an embodiment, the toy may be heavier than water and have a weight and volume to have negative buoyancy. This may be achieved by the body having sufficient weight to cause the toy to slowly sink, but is able to mimic a swimming action to drive the toy to or towards the surface. The toy may have a head  200  that, when the toy is in use, remains above to the rest of the toy. In an embodiment, the head  200  sits directly vertically aligned with the elongate axis XX of the toy. The toy has a buoyancy to let it sink slowly. It is weighted in a manner to (a) help make it sink in water and (b) bias the end of the body opposite the head towards the bottom of the body of water. The toy/body may be appropriately weighted with its centre of mass on the tail side of the centre of buoyancy. This keeps the head  200  higher than the tail  2 . 
       Tail Movement 
       [0141]    The toy tail assembly  2  comprises a toy tail  21  that may make a swishing oscillatory like motion relative to the body and thereby propel the toy through the water. In an embodiment, such propelling may be vertically or near vertically. In an embodiment, the body is made from a rigid plastic and the tail  21  from a more flexible plastic. However, alternative appropriate materials may be used. 
         [0142]    In the preferred embodiment the body assembly  1  comprises a left shell body  11  and a right shell body  13 . The toy tail assembly  2  is pivotally or floatingly disposed from the body assembly. The toy tail assembly  2  may gain support of both the left shell body  11  and right shell body  13 , and a sealing ring  24  and a support bracket  23 . A tail shaft  22  of the toy tail assembly  2  has an inner end and an outer end. The inner end penetrates through a central hole of the sealing ring  24 . The outer end of the tail shaft  22  carries the toy tail  21 . 
         [0143]    In an embodiment, a coil and magnet arrangement is disposed in the body assembly  1 . The coil may be energized to cause the tail to oscillate. 
         [0144]    In an embodiment, the coil and magnet arrangement may be presented in a manner where two magnets  12  and one coil  26  are present in the body assembly  1 . However, in another embodiment, there may be one magnet and one coil, as illustrated in  FIG. 8  or one magnet and two coils, as illustrated in  FIG. 7 . 
         [0145]    In an embodiment, in use, when the coil or coils are energized, magnetic poles are induced in the coil or coils and these magnetic poles interact with the magnetic poles of the magnet or magnets. 
         [0146]    In an embodiment, the inner end of the tail shaft  22  carries the coil  26 . The inner end of the tail shaft extends into a hole  251  of a coil bracket  25 , and a coil  26  is fixed in the central hole  252  of the coil bracket  25 . 
         [0147]    In an embodiment, the body assembly carries two magnets  12 . These two magnets  12  are respectively secured each on an inner side of each right and left side shells  11 ,  13 . Therefore, a magnet  12  sits of each side of the coil when it is in a central location. In an embodiment, the opposite surfaces of the two magnets are of the same polarity, and the coil is disposed such that the coils central axis is perpendicular to the central horizontal axis through the aquatic toy. In an embodiment, when in use, when the coil is energized, the magnetic poles formed in the coil cause the coil to be are attracted to one of the magnets and repelled by the other of the magnets. 
         [0148]    In an embodiment the magnet and coil configuration may be different, but have the same effect. For example, as illustrated in the embodiment illustrated in  FIG. 8 , when an alternating current to applied to the coil  226 , an alternating magnetic pole is induced in the coil, which interacts with the single magnets  212  pole, causing the shaft  222  and tail  221  to move. Similarly, as illustrated in the embodiment illustrated in  FIG. 7 , when an alternating current is applied to each of the coils  326 ,  327  the magnetic poles induced in the coils may interact with the poles of the magnet and cause the magnet and thus the shaft  322  to move. 
         [0149]    In an embodiment illustrated in  FIG. 3 , a drive control circuit  3  is disposed in the body assembly  1 . When the drive control circuit  3  supplies electric current to the coil  26  the magnetic field induced in the coil  26  interacts with the magnetic field produced by both magnets  12 . This creates an attraction force at one side of the coil  26  and a pushing force at the other side of the coil  26 . This causes the coil  26  and bracket  25  to pivot or lean towards one or other magnet  12 , causing the tail shaft  22  to swing in the opposite direction to the movement of the coil and bracket. When the current direction is changed, the force directions are changed accordingly and the tail shaft  22  is moved in the opposite direction. Thus with consecutive changes in the current in the coil  26  and changing of the magnetic poles in the coil, the tail shaft is causes to swing in an oscillatory manner. The swinging of the tail causes the tail  21  to propel the body assembly  1 . The swinging of the tail causes the toy to advance in a forward direction. This forward direction may have a component that is vertical and upwards due to the toy being appropriately buoyed and weighted. This provides the toy with thrust in a direction to prevent it from sinking to the bottom of the body of water. The swishing may be periodic or vary in rate or amplitude. It may be random or pre programmed or user controlled. This may cause the toy to advance upwards and to sink towards the bottom and advance up again. This happens repeatedly so that the toy is constantly in motion when in the water. 
         [0150]    Additionally, in an embodiment, the toy comprises an activation circuit. The activation circuit is associated with the drive control circuit and is provided to activate the energization of the coil(s). The activation circuit may be selected from one of (a) a vibration switch and (b) moisture sensor or (c) terminals of a circuit or switching circuit that complete an electrical circuit via water in which said aquatic toy may be placed. 
         [0151]    As illustrated in the embodiment illustrated in may  FIG. 14 , the net force of thrust Ft of the fin acting on the body may be in a direction that is parallel the line between the centre of mass (COM) and centre of buoyancy (COB). The COB is above the COM in order to create a righting moment as illustrated may in  FIG. 16  if the body comes out of balance. The tendency may be for the COB and the COM to come into vertical alignment when the toy is submerged. In alternative forms, it may be see that the thrust force Ft may be offset from the line passing through the COM and COB as illustrated in  FIG. 15 . The force Ft is still acting in a direction to encourage the toy towards the surface of the body of water. If offset as per the force Ft on the left side of the body as illustrated in  FIG. 15 , a rotation may be induced causing the toy to move towards the surface on a slight heel. This is because the force Ft is not acting though the COM/COB. The net force Ft may not act vertically but at an angle to the vertical as seen on the right hand side of the body in  FIG. 15 . This force Ft should still have a component that acts in the vertical direction as seen from the vectors associated with force Ft. This vertical component may encourage the toy to move towards the surface. The vertical component of force Fv applied by the fin to the body may be of a quantum to overcome the difference between the force, Fg, acting on the toy due to gravity less its buoyant force, Fb as illustrated in  FIG. 17 . 
       Turning Movement 
       [0152]    In an embodiment, a deflecting force may be produced when the toy advances through the water if the toy tail is at an offset angle to the toy body. If the toy&#39;s buoyancy is biased to keep the head of the toy vertically aligned with the elongate direction of the body, this deflecting force may cause the toy to swim on an angle to the vertical. Different durations of swing of the toy tail on opposite sides of the toy centerline may cause a non-symmetric deflecting force and the toy may alternate swimming on sides accordingly. Thus the toy&#39;s moving direction/angle of inclination may be changed by altering the forward-direction and backward-direction current pulses in the coil  26 , which is supplied by the drive control circuit  3 . The altering of the current pulses may be by way of duration, amplitude or by applying an offset sine wave current pulse to the coil or coils. 
       Drive Control Circuit 
       [0153]    In an embodiment the drive control circuit  3  comprises a PCB  31 , a vibration switch  32  and LED indicator lights  34  and  35 . The indicator lights  34 ,  35  are capable of showing a status of activation of the toy or charging of the toy respectively. The drive control circuit may be powered by a battery  17 . 
         [0154]    The vibration switch  32  consists of a central post  321  and a vibration spring  322 . When vibration of the toy body is transmitted to the spring, the spring starts to swing and may contact with the central post when the swing exceeds a certain amplitude. Accordingly an electric signal is generated to activate the drive control circuit. 
         [0155]    In some forms of the invention, the drive control circuit  3  may include an infrared receiving tube  33 . The infrared receiving tube  33  is capable of receiving a transmitted remote control signal from a transmitter outside the toy. In response to the transmitted signal, the control circuit may execute a corresponding operation according to the received signal. 
         [0156]    Referring to  FIG. 6 , the operation of the indicator lights  34 ,  35  may be described. When the drive circuit is in operation, the LED indicator light  34  is lit up. Alternatively, when the toy is charging, a different LED indicator light  35  is lit up. Light from each of these hits the incident surface  141  and then the reflector  14 . Light may be reflected by two reflecting surfaces  142  to be emitted to represent toy eyes  143 ,  144 . 
       Angle of Inclination 
       [0157]    In an embodiment, the toy body may be internally provided with an additional coil  15 , and at least one additional magnet  16  (however, more than one magnet may be used), that is attached to the battery  17  that powers the drive control circuit  3 . A magnetic field generated by the coil when the coil  15  is supplied with an electric current (from the drive control circuit), interacts with the magnet  16  to create an attraction force or a pushing force to drive the battery  17  to move. When the battery moves towards the head, the centre of mass of the toy may shift forward simultaneously. This moves the centre of mass towards the centre of buoyancy making the toy less biased to the preferred vertical orientation. When the magnet  16  drives the battery  17  to move backward towards the tail, the opposite effect occurs. 
         [0158]    An alternative method of changing the centre of mass of the toy is to fix a magnet  16  and allow a coil to be movable, such that the coil drives the battery or any other counterweight member to move. The movable counterweight member may comprise a non-magnetic material in order to avoid producing a magnetic force between the movable member and the magnet that would interfere with the correct action of the coil. 
         [0159]    In an embodiment, the toy&#39;s centre of mass may be adjusted in a right-left direction using either of the above methods but when the above mechanisms are arranged transversely. The toy&#39;s centre of mass may also be adjusted when either of the above mechanisms is arranged horizontally. 
       Charging 
       [0160]    In an embodiment, the battery  17  may be charged through a port in the toy shell. A Micro-USB plug or other suitable charging plug may be inserted into a charge socket  19  by opening a waterproof cover  18  on the toy shell. 
         [0161]    In particular, the charging system of the drive control circuit  3  may be designed to be charged via a USB power supply, so that a charger with a Micro-UBS charging head may be used in charging. 
         [0162]    However, other plug and socket arrangements for charging as are known in the art may be used with the aquatic toy of the present invention. 
         [0163]    The charging cover  18  is shown in  FIG. 4 . The charging cover comprises a post  183 , plug  184  and base  181 , that when the charging cover  18  is closed over the port  19 , is inserted into port  19 . The cover  18  is made of a plastics material and each of the post  183  and plug  184  as well as the base  181  fit into the shell of the toy body, so as to cause a watertight seal of the charging port area of the aquatic toy. 
       Remote Control 
       [0164]    In an embodiment, the aquatic toy may utilise infrared remote control. However, radio remote control could also be used, or a computer and a cell phone may alternatively be used for controlling the toy if, for example, a Bluetooth receiver or WIFI receiver is disposed in the toy body. Furthermore, in some embodiments if the toy body was internally provided with sensors capable of sensing acoustic-optic variation or touch and a microprocessor capable of processing the sensing signals, autonomous control may be realized. 
       Reconfigurable Variation 
       [0165]    In an embodiment, the centre of mass may be displaced relative the centre of buoyancy to invert the toy. In this situation the centre of mass may move to the other side of the centre of buoyancy as defined above. The head of the toy may face down and the fin may then be in an orientation to drive the toy towards the bottom of the body of water. In an inverted orientation, the buoyancy of the toy may be positive so that when the fin is for example not operative, the toy may slowly rise towards the surface. 
         [0166]    A person may be able to adjust the centre of mass and/or centre of buoyancy and increase or decrease its mass or buoyancy. The toy, overall, may hence be reconfigured to have a specific gravity of less than 1 or equal or greater than 1. A negatively buoyant elastic band  300  may be provided as one means of achieving this. The weighted elastic band is able to be repositioned about the body of the toy so as to allow the centre of mass to be moved relative the centre of buoyancy. Other ways of allowing a mass providing member and/or a buoyancy providing member to be shifted externally or internally of the body of the toy are within the scope of this invention. The band may instead have positive buoyancy. Or the toy may be reconfigured by for example having interchangeable head elements that may connect to the trunk, as shown in  FIGS. 10-13 , which may have different buoyancy and/or mass characteristics. Inflatable portions may be included so as to allow a person to inflate or deflate such portions to change the toy&#39;s buoyancy. It is also contemplated within the scope of the invention for the centre of mass and centre of buoyancy and/or mass and buoyancy to be adjusted to allow the toy to be positioned horizontally at the surface of the body of water and to be propelled along the surface of the water. This may be achieved by removing the negatively buoyant band and the resulting toy being positively buoyant and the centre of mass and centre of buoyancy being positioned to allow such an orientation of the toy to be achieved. 
         [0167]    The biomimetic toy of the present invention may realistically simulate up and down movement in a body of water, turning and up-down traverse and optionally be inverted and/or be made to swim horizontally at the surface of the body of water. In an embodiment it may also be operated flexibly and conveniently and may be controlled by various drive circuit programs or by remote control. 
         [0168]    In an embodiment, the biomimetic toy may be flexibly driven and its centre of mass may be adjusted by interacting variable magnetic fields in the coil with fixed magnetic field of a magnet. 
         [0169]    The exemplary embodiments herein described are not intended to be exhaustive or to limit the scope of the invention to the precise forms disclosed. They are chosen and described to explain the principles of the invention and its application and practical use to allow others skilled in the art to comprehend its teachings. 
         [0170]    As may be apparent to those skilled in the art in light of this disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.