Abstract:
An underwater motive device utilizes a plastic rear housing which includes a battery storage space sealed with a tight fit to provide sealing, a pressured removal system is provided to pressurize the sealed battery chamber to enable the front wall to be removed. The motor is microprocessor controlled for safety by providing a slight delay before energizing the motor, and by providing some time in residence at a slow speed before switching to a higher speed. The result is a safe underwater motive device which will not accidentally become power actuated before the user is able to securely grasp and direct it, and which will not go to full speed except from a low speed to give the user a chance to stabilize himself in the water. Further, the control circuitry includes other features to provide both long battery life, good serviceable usage and battery preservation and motor preservation.

Description:
FIELD OF THE INVENTION 
   The present invention relates to improvements in the technology relating to in water and underwater mechanical motive structures and particularly to improvements relating to a battery powered device for propelling swimmers and divers forward. 
   BACKGROUND OF THE INVENTION 
   Underwater motive devices have been known since the 1950&#39;s. Most of those earlier devices were metal and were built like small submarines. Access was had through hatches which had to be securely bolted or clamped in order to resist taking on water at depth. As a result, the underwater motive devices were large, bulky and designed with a mind to limit outside access to limit the sealing areas provided for service access. 
   The early underwater motive devices were also expensive, and heavy such that the only effective market was professional divers because of both the cost and strength required to handle the unit under water. Because of the sealed nature of the units, rechargeablility caused considerable time in opening, inspecting and re-sealing the units. 
   Further, because early underwater motive devices were meant for serious under water work the full power of the unit was made instantly available in order to enable a sealed actuation switch to be provided through the wall of the unit to the outside. Instant-on full power was another reason that the early underwater motive devices were dangerous due to increased lack of controllability. The user had to be skillful to avoid being raked by nearby objects in addition to other user problems. 
   Another early problem was ballast. Most underwater motive devices were built for salt water density, but density can change from ocean to ocean (the Persian Gulf is saltier) and based upon water temperature. Adjusting the ballast was a problem because each time an adjustment was desired to be made, it involved a complicated breaching of the sealed outer housing. 
   What is needed is a underwater motive device which is (1) safer, (2) more easily ballast weighted, (3) more easily recharged and serviced, and (4) which is light weight and portable. 
   SUMMARY OF THE INVENTION 
   An underwater motive device utilizes a plastic rear housing which includes a battery storage space which is “o” ring sealable with a front wall. Because the “o” ring seal is multiple and of tight fit to provide sealing, a pressured removal system is provided to pressurize the sealed battery chamber to enable the front wall to be removed. The battery is not only readily accessible for charging or replacement, but the front wall is easily removed and replaced. The motor is microprocessor controlled for safety by providing a slight delay before energizing the motor, and by providing some time in residence at a slow speed before switching to a higher speed. The result is a safe underwater motive device which will not accidentally become power actuated before the user is able to securely grasp and direct it, and which will not go to full speed except from a low speed to give the user a chance to stabilize himself in the water. Further, the control circuitry includes other features to provide both long battery life, good serviceable usage and battery preservation and motor preservation. The control circuit preferably constantly monitors the current through the motor and shuts down the motor if the current rises above a predetermined level. The circuit preferably constantly monitors the battery voltage and shuts down if the voltage is less than a predetermined level. The circuit preferably constantly measures the temperature of the motor and shuts down if the temperature is above a certain predetermined level. Further, the circuit will preferably constantly measure the rate of change of the current and shut down of the rate of change of current is above a predetermined level, the rate change being either positive (increasing current) or negative (decreasing current). Further, the circuit uses two reed switches that can be independently switched to their conducting state and it is preferred that both must be conducting for the motor to be switched on. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which: 
       FIG. 1  is a perspective view of the underwater motive device of the present invention; 
       FIG. 2  is a side view of the underwater motive device of  FIG. 1 ; 
       FIG. 3  is an exploded view of the underwater motive device of  FIGS. 1 and 2 ; 
       FIG. 4  is a partially exploded side sectional view of the underwater motive device of  FIGS. 1-3  and illustrating the use of an air pump to provide internal pressure to overcome the friction of sealing in removal of a sealing member; 
       FIG. 5  is a front view of the underwater motive device of  FIGS. 1-4 ; 
       FIG. 6  is a rear view of the underwater motive device of  FIGS. 1-5 ; and 
       FIG. 7  is a block diagram schematic illustrating the relationship of the battery to a control circuit which performs a sequential safety control and measures current use. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The description and operation of the invention will be best initiated with reference to FIG.  1 . An underwater motive device  21  has housing members including a front cone  23  and rear main housing  25 . From the rear main housing  25  a number of fan housing supports  27  support a fan housing  29 . In addition to the fan housing supports  27 , a cage  31  provides stability to the fan housing  29 , and is supported by it. 
   The rear main housing  25  extends somewhat rearwardly of the cage  31  and rotatably supports a propeller  35 . A rearmost screen guard  37  is only partially see at the rearward rim of the fan housing  29  and is excluded from being shown adjacent the propeller  35  for clarity. 
   At the top of the rear main housing  25  is a handle bar support  41  which includes a top generally hydrodynamic area  43  leading to a pair of oppositely disposed handle bars  45  which are angled slightly rearwardly along their downward path extent. The handle bars  45  are intended to be grasped with the underwater motive device  21  held generally near the user&#39;s chest with elbows somewhat tucked in and on either side of the fan housing  29 . 
   A manual switch  49  has a curvature partially covering the front of one of the handle bars  45  for easy access and grasping. A rotatable slender selector switch  51  is mounted to pivot in a generally horizontal plane underneath the handle bar  45  opposite the switch  49 . Both switches  49  and  51  are pivot structures mounted with fittings which naturally resist the water side pressure. Both switches  49  and  51  may have an internal component as a reed switch to further isolate the electrical circuitry, especially switch components from contact with any water. The handle bar support  41  is meant to flood as it removes itself as a bouyancy consideration. Rotatable slender selector switch  51  therefore may have associated with it a high degree of arc for operation in order to visually verify its orientation. Further, once familiarity is had with the “on” and “off” position, the user does not have to be able to view a position of a typical on and off switch closely, which would lead to confusion and mistake as to the switch&#39;s state. 
   The front cone  23  has a pair of swinging latches  55  which pivot about an insertion point in the front cone  23  and which engage a locking structure (not seen in  FIG. 1 ) on the rear main housing  25 , to insure that the front cone  23  is held securely in place. The latches  55  may preferably have ramps and grooves on their locating faces to ensure the latches are in an over center position when locked. This swing latch mechanism, as will be seen, also serves as a secondary gauge to insure that the internals of the underwater motive device  21  are properly and securely held in place. The sealing system avoids the use of face sealing so that latching is less troublesome and involves minimum force. 
   Referring to  FIG. 2 , a side view enables a better view of many of the structures seen in  FIG. 1 , particularly the placement of the handle bars  45 . Seen also is a front ring  57  which supports the cage  31  which is suspended between the fan housing  29  and the front ring  57 . 
   Referring to  FIG. 3 , a user&#39;s exploded view illustrates the access which a user has to both provide for ballast and for battery change out or recharge. Beginning at the right, the rear main housing  25  is seen as having a latch projection  61  which extends outward and rearward and has sufficient thickness and base for a good mechanical holding force. To the left of the latch projection  61  is seen a rim  63  exposed when the front cone  23  is removed. Adjacent the rim  63  is a relatively deep somewhat cylindrically shaped, actually an elliptical area  65  which forms a sealing surface and which leads to a shaped area  67  which is circumferentially inward of the ellipitical area  65  at a point deeper within the rear main housing  65 . This area is shaped to accommodate two rectangular battery sizes with the portions of the shaped area  67  which deviate from rectangularity on one orientation to provide a slot for wire and attachment accommodation using the rectangular shape in the another orientation. 
   A battery  69  is shown connected by a pair of slide terminals to a wire set and connector  73  leading into the front opening of the rear main housing  25  past the rim  63 . Utilizing this basic configuration, the battery  69  can be easily grasped and extracted from the shaped area  67  and can be easily replaced without much interference from the wire set and connector  73 . 
   Just ahead of the battery  69 , a sealing structure  75  is seen. Sealing structure  75  has a rear cylindrical portion  77  which includes several “o” ring type projections  81 , two of which are seen on the rear cylindrical portion  77 . Even without the “o” ring type projections  81 , the rear cylindrical portion  77  forms a close fit with the relatively deep ellipitical area  65  with the “o” ring type projections  81  set to engage the surface of the relatively deep ellipitical area  65  to more completely form a seal. The area beyond the shaped area  67  and rearward of the rear main housing  25  is designed to be sealed utilizing other structures, including the motor and drive shaft(not shown). 
   Sealing structure  75  also includes a flange  83  which sets, along with the length of the relatively deep ellipitical area  65  matched with the rear cylindrical portion  77 , the depth with which the sealing structure  75  can enter inside of the rear main housing  25 . Ahead of the flange  83 , a pair of key apertures  87  are surrounded by outwardly extending keyed bosses  89 . The key shape enables a non cylindrical shape to enter and lock when not in its entry alignment. As will be seen, the key apertures  87  will be used to lock the sealing structure  75  back against the rear main housing  25 . 
   The front of the sealing structure  75  includes a cylindrical forward wall  91  which protects and covers a center fitting  93 . The center fitting  93  is a valve which permits entry of air upon having an air fitting inserted in an aperture  95  of the fitting. Any type of valve is permissible such as a flapper valve or the device can work well without any valve as the seal between the fitting  93  and an inserted tube during pressurization is all that is necessary to provide a pressurized assist to remove the sealing structure  75 . 
   Even where no valve is used, the placement of the fitting  95  is so as to allow very little or no fluid flow to the rear of the sealing structure  75 . Since the volume behind the sealing structure  75  is pressure tight, a significant amount of water would have to enter to fill the area about the fitting  93  and beyond the height of the fitting  93 . Further, as will be seen, a ballast structure is provided which further restricts the amount of access to the fitting  93  and further restricts the displacement which can occur in the front cone  23 . 
   Because the rear cylindrical portion  77  and the relatively deep ellipitical area  65  have so much common area and provide such a strong seal, the frictional interaction creates a significant force required to separate the sealing structure  75  from the rear cylindrical portion  77 . Because of the profile of the underwater motive device  21  and due to its small size the lack of structures to which significant manual force can be applied, the pressurized assist works well for separation. Further, where a shutting valve is provided within the fitting  93 , partial pressurization can be applied to further preclude any leakage through the fitting  93 . 
   Forward of the sealing structure  75 , a shaped ballast  97  is seen. Ballast  97  includes a rear shaped rim  99  and a cup shaped forward portion  101 . A front surface  103  includes a pair of projections  105  for location on top of the handle bars  45  when ballast is adjusted. The rear of the ballast  97  (not seen in  FIG. 3 ) includes an indentation to accommodate the protrusion of the fitting  93 . The indentation (not shown in  FIG. 3 ) also provides a sealing cap to enable the ballast  97  to be controllably filled with water to set the degree of ballast desired. This is particularly important where uses change from salt to fresh water usage. 
   Also seen is a pair of insertable latch and lock dogs  109 . Each lock dog  109  includes a relatively planar portion  111  to which an annular keyed plug  113  is attached at a right angle. A key projection  115  extends from the annular keyed plug  113  only at its most distal end, away from the relatively planar portion  111 , in order to enable it to rotate after entering the key apertures  87 . 
   Also seen on the front cone  23  are a pair of keyed side apertures  117 , only one of which is seen in  FIG. 3. A  phantom view of a latch and lock dog  109  is shown in dashed format and identified with the numeral  119  and is shown in its inserted and rotated position. In this rearwardly extending (with respect to cone  23 ) position, the insertable latch and lock dog  109  engages the latch projection  61  to hold the front cone  23  in place. However, the latch and lock dog  109  also engaged the keyed aperture  87  and utilizes that structure to achieve the whole of its depth of engagement. 
   In terms of assembly, and starting with the structures seen in  FIG. 3 , first the battery, preferably charged, is inserted into the shaped area  67 . Next the rear cylindrical portion  77  of the sealing structure  75  is inserted into the rear main housing  25 . The sealing structure  75  is inserted into the rear main housing  25  to its full extent, and until flange  83  makes even contact with rim  63 . 
   Next, the ballast  101  is moved into position within the cylindrical forward wall  91  and over the center fitting  93  such that the rim  99  of the ballast  97  comes to rest beyond the level of the key apertures  87  within the cylindrical forward wall  91 . Once the ballast  97  is brought to this position, any intrusion within the cylindrical forward wall  91  will further fix its position. Next, the front cone  23  is brought over the ballast  97  and over the outwardly extending keyed bosses  89  until a rearward rim  121  rests against the front side of the flange  83 . The apertures  117  are brought into alignment with the key apertures  87  of the sealing structure  75 . 
   Next, each annular keyed plug  113  of an insertable latch and lock dogs  109  is inserted through the aligned apertures  117  and key aperture  87 . The orientation of the key projection  115  of the annular keyed plug  113  is oriented so that the relatively planar portion  111  is directed forward and away from the rim  121  upon insertion and so that it can then be rotated 180° to the rear to latch. Once the insertable latch and lock dogs  109  are rotated more than a few degrees, the front cone  23  and sealing structure  75  are locked together, with the rim  99  of the ballast  97  being secondarily trapped behind the inward projection of the annular keyed plug  113 , and further locked down by the rotation of the tip end of the key projection  115  against a front face of the rim  99 . 
   As the pair of insertable latch and lock dogs  109  are brought maximally rearward, at the point approaching about 170°, a latch member  123  is brought around the latch projection  61  extending from the rear main housing  25 . Once brought to the 180° point the entire sealing structure  75  is locked onto the rear main housing  25 . The latch and lock dogs  109  to an extent operate as an indicator that the sealing structure  75  is fully seated, as once seating occurs sealing structure  75  is difficult to remove. The pressure against the latch and lock dogs  109  once latched, will be minimal. 
   Referring to  FIG. 4  a partial side sectional view is useful illustrating both the partial assembled view and an explanation of dis-assembly at least to the point of access of the battery. In gaining access with regard to the assembled versions seen in  FIGS. 1 and 2 , the latch and lock dogs  109  are rotated away from engagement with the latch projection  61  and to a full forward position rotated 180° from the locked position. As can be seen in  FIG. 4 , the keyed side apertures  117  include a flat portion  125  forming the key projection of the keyed side apertures  117 . This provides clearance for the key projection  115  and enables complete removal of the latch and lock dogs  109 . 
   The front cone  23  is then removed, along with the ballast  97 . On the ballast  97  is seen an indentation  129  previously referred to which accommodates the protrusion of the fitting  93 . Not shown on the ballast  97  in this side sectional view are the holes and closures for allowing water in and out to affect bouyancy and are generally situated to either side of the indentation  129 . Indentation  129  also enables the ballast  97  to be better manually gripped. 
   Shown to the lower left of  FIG. 4  is an air pump  131  having an inlet port  133  and an outlet port  135 . A connection tube  137  leads from the outlet port  135  to the fitting  93 . The air pump  131  need be no more than a simple plastic pump as the pressure developed need not be great, probably not more than 7-10 PSIG above ambient pressure. The force causes the sealing structure  75  to emerge from within the rear main housing  25 . As such, no physical force needs to be expended on the sealing structure  75  and removal, even in the presence of strong, well fitting sealing surfaces, is facilitated. Once the sealing structure  75  is removed, normal access is had to the shaped area  67  and beyond. 
   Also seen in  FIG. 4  is the possibility of a further, optional sealing member  141  which provides a further splash seal which causes any entering water to go around the rear edge of the member  75  and into an annular area  145  before having to negotiate the inside of the seal  141  to attempt to enter the area holding the battery. Also seen to the rear of the fan housing  29  are further details of the rearmost screen guard  37  including its cage members  147 . 
   Referring to  FIG. 5 , a front view gives a better illustration of the profile and orientation of the components of the underwater motive device  21 . Here, the main body of the rearmost screen guard  37 , as well as the cage  31 , have been removed so that the components may be more readily identified without visual interference. The manual switch  49  and the rotatable slender selector switch  51  are seen to operate through a pair of bosses  151  and  153 , respectively on the underside of the handle bar support  41 . The use of the bosses  151  and  153  provide a stable support for the manual switch  49  and the rotatable slender selector switch  51  while limiting the physical access through the handle bar support  41 . Further, the underside mounting helps to protect these structures from inadvertent impact with other objects as well as user impact, intentional or unintentional. The movement of the manual switch  49  is slight and the internals of the switch are set such that a small movement to depress the band portion of the manual switch  49  toward the handle bar  45  will trigger the start of the control sequence, and then powered motion of the propeller  35 . A delay is typically a characteristic of the contol circuit. For the rotatable slender selector switch  51 , and especially for visual notice, the rotation involved is nearly 160° so that the user has a definite indication of power ability. There are a number of “off” positions such as at 90°, 180° and more and any combination of possible positions may be used. The general idea is that the user can readily see the position of the switch. 
   Since the handle bar support  41  and oppositely disposed handle bars  45  are designed to flood, sealing is not needed. Further, the clearance can be significant to prevent buildup of sand, debris etc. The bosses  151  and  153  which provide a pull inward for the manual switch  49  and the rotatable slender selector switch  51 . The fan housing supports  27  are shown prominently with the cage  31  having been removed for clarity. 
   Referring to  FIG. 6 , a rear view of the underwater motive device  21  is shown with the rearmost screen guard  37  having a radial net member  155  shown in place to illustrate the manner in which any user contact with the propeller  35  is guarded against. The rearmost screen guard  37  should only be removed in order to service the propeller  35  and the nut  157  and bolt  159  fitting holding it into an operable supported relationship with the motor (not shown). 
   Referring to  FIG. 7 , a block schematic diagram of a circuit control system  161  is shown. Battery  69  is connected to a CONTROL CIRCUIT  163  which provides a sequential control as well as feedback over-current control. A pair of connections provides direct current flow. The CONTROL CIRCUIT  163  is connected to the on and off switch  51  seen in the previous figures external to the underwater motive device  21  as rotatable slender selector switch  51 . The CONTROL CIRCUIT  163  is also connected by a pair of connections to a start switch  49  seen as manual switch  49  in the previous figures. 
   The CONTROL CIRCUIT  163  has a pair of connections to a MOTOR  165 . Feedback current control can be obtained by monitoring the pair of power lines or by monitoring a further feedback connection  167  which may be provided for sensing current, temperature and more at various points within the motor  165 . The motor  165  is connected mechanically to the propeller  35  previously seen in the figures. 
   As can be seen, the on/off switch  51  is generally used to disable the operation of the underwater motive device  21  and acts as a master shut down switch, especially to prevent actuation when the underwater motive device  21  is out of the water and when it might come into contact with other structures. 
   The CONTROL CIRCUIT  163 , once the switch  51  is closed and upon closure of the start switch, may provide a slight delay in time before energization of the motion  165 . This will prevent the underwater motive device  21  from starting before a user is completely ready. Put another way, it gives the user a moment to make certain that the underwater motive device  21  handle bars  45  are securely grasped before forward movement. This will also insure that in the event that the user grasps the right handle bar  45  first and accidentally trips the manual switch  49  that the underwater motive device  21  will not instantly start at a point in time before the user is prepared. 
   Further temporal programming includes at least one of a ramped or stepper circuit to provide for increases in speed based upon the time since initial actuation. This serves to start the motor  165  at a relatively lower speed to end up with a relatively higher speed only after the user has been under way for a short time. The method of achieving the higher speeds can be by step or ramp. Step will give a definite power indication to the user, while a ramp function will cause the increase in speed to be gradual. This ramping avoids a lurch of power at startup. 
   In addition to motor  165  current detection, the CONTROL CIRCUIT  163  is enabled to limit or shut down the motor  165  if the current rises above a predetermined level. Further, the CONTROL CIRCUIT  163  preferably constantly monitors the battery  69  voltage and shuts down the motor  165  if the voltage falls below a predetermined level. The CONTROL CIRCUIT  163  can also preferably constantly measure the temperature of the motor  165  to shut it down if the motor  165  temperature is above a certain predetermined level. 
   In terms of utilization, the underwater motive device  21  offers advantages previously not seen in underwater motive devices. The swinging latches  55  provide an integrated quick method of disassembly, while the air assisted disassembly structure enables a high sealing structure. The ballast  97  can be trimmed by filling and emptying it achieve the desired ballast  97  weight. The ballast  97  can be attached to the handlebar  45  in order to allow the trimming to be carried out without the ballast  97  being in its normal position. The front grille is novel because it can be securely locked in position using a pair of simple quick release latch. 
   While the present invention has been described in terms of an underwater motive device, and more particularly to a particular structure and system which utilizes a control set which provides power delay and stepped or ramped power increase, this mechanism can be applied to other devices. 
   Although the invention has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art.