Abstract:
A body board ( 10 ) having a pair of side rails ( 13, 14 ), the body board ( 10 ) including a fin ( 20 ) that extends laterally from at least one side rail ( 14 ) of the body board ( 10 ).

Description:
FIELD OF THE INVENTION 
     This invention relates to a body board and, in particular, relates to maintaining stability of a body board when riding a wave. 
     BACKGROUND OF THE INVENTION 
     Body boards are typically constructed from an expanded closed-cell foam. The body board has a top skin on which riders lay and, a bottom, smooth skin which contacts the wave when riding the body board. A pair of side rails extend between the top skin and bottom skin along a major portion of the perimeter of the body board. 
     When riding a wave, the object of most riders is to cut across a face of the wave to obtain a long ride and to perform tricks such as spinning the board through 360°. To enable the body board to travel across the face of the wave, a rider must lean to one side of the body board to dig one of the rails into the face of the wave. 
     In particular wave conditions, or through a riders lack of experience, or rider error, the rail is often not dug into the face of the wave. This can cause the body board and rider to slide down the face of the wave usually causing a “wipeout”. 
     To prevent a body board from sliding down the face of the wave, downwardly extending fins are attached to the bottom skin of the body board. The fins work well in enabling a rider to guide the body board across the face of the wave without slippage of the body board down the face of the wave. 
     However, the fins often prevent tricks being performed that involve quick rotation of the body board. Further, the fins can cause injury to swimmers or other riders if run over by the body board. Hence, fins that extend downwardly from the bottom skin are undesirable and therefore are not in common use by riders. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to overcome or alleviate some of the above disadvantages or provide the consumer with a useful or commercial choice. 
     In one form the invention resides in a body board having a pair of side rails, the body board including one or more fins that extend laterally from at least one side rail of the body board. 
     The body board may be made from any suitable material such as a closed-celled foam. The body board may have all or some of the features of standard body boards. 
     The fin may be made from any suitable material. Typically the fin is constructed from inflexible materials such as hard plastics. 
     Typically there is a fin mounted to each side rail of the body board. The fins may be fixed relative to the side rails. However, preferably the fins are able to be extended or retracted with respect to the side rails. 
     When the fins are able to be extended or retracted, typically they are movable from within a respective housing. The housings may be formed from an inflexible material and may be located within the side rails of the body board. The housings may assist in preventing flexing of the body board. The fins may be pivotally mounted within the housings. 
     In one embodiment, a connecting rod may be attached to each fin to extend or retract the fins. A biasing means such as a spring may form part of the connecting rod such that when the fin is bumped, the fin can move slightly inwardly or outwardly to protect the fins from damage. 
     A control means may be used to control the movement of the connecting rods. The control means may be of any suitable form. 
     The control means may comprises a pawl that operates two parallel, spaced ratchets. Rotation of the pawl may cause opposite longitudinal movement of each of the ratchets with respect to each other. Each ratchet may be connected to a connecting rod to extend or retract the fin. 
     Alternatively, the control means may be a shaft that has a T-head. Each end of the T-head may be attached to a connecting rod such that upon rotation of the shaft, the connecting rods extend or retract the fins. 
     Still alternatively, the control means may be a shaft connected to a cam. The connecting rods may be biassed to retract the fins so that upon rotation of the shaft, the cam pushes the connecting rods outwardly to extend the fins. 
     The control means and connecting rods are preferably hidden within the body board. 
     The control means may be operated by an externally mounted control handle or knob or the like. Alternately, a removable key or spine may be used to operate the control means. 
     In a second embodiment, each fin may be moved independently of each other. Each of the fins may be biased outwardly from their respective housings. A helical spring, a leaf spring, a resilient block or the like biasing means can be used to bias the fins outwardly. 
     Guides may be provided within the housing to guide movement of the fin within the housing. A stop may be provided on the housing or on the fin to stop the fin from being extended beyond a desired position within the housing. 
     A retaining means may be provided within the housing to retain the fin within the housing. The retaining means may allow the fin to be extended to a plurality of discrete positions relative to the housing. The retaining means may be a catch or latch or the like device. The catch or latch may be biased toward a retaining position and may be moved to a extension position to allow the fin to be extended. 
     The fin may have at least one holding means for engagement with the retaining means. The holding means may be a stepped portion, land or aperture. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will be described with reference to the accompanying drawings in which: 
     FIG. 1 is a plan view of a body board according to one embodiment of the invention. 
     FIG. 2 is an end view of the body board of FIG.  1 . 
     FIG. 3 is a sectional plan view of a fin unit mountable within a body board according to a second embodiment of the invention. 
     FIG. 4 is an end view of a fin unit mountable within a body board according to FIG.  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 and 2 show a body board  10  with a core formed from a closed-cell foam. The body board  10  has a top skin  11  on which a rider lies and a bottom skin  12 , made from a smooth material, which contacts a wave when the body board  10  is in use. A pair of side rails  13  and  14  and end rail  15  separate the top skin  11  and the bottom skin  12  along a major portion of the perimeter of the body board  10 . A nose  16  is formed at the front of the body board  10  where the top skin  11  and bottom skin  12  are joined. An arm rope attachment device  17  extends through and is located on an upper portion of the body board  10 . 
     Two housings  18  and  19  are located within the side rails  13  and  14 . The housings  18  and  19  are made of a rigid plastics which assists in preventing flexing of the body board  10  when riding the wave. This enhances the body board&#39;s performance and also the body board&#39;s life as the core is not compressed due to flexing. 
     Two fins  20  and  21  are pivotally mounted via respective pins  22  and  23  within the housings  18  and  19 . Connecting rods  24  and  25  are attached to respective fins  18  and  19  with springs  26  and  27  forming part of the connecting rods. The springs  26  and  27  allow slight inward and outward movement of the fins  18  and  19  if the fins are knocked against an object. This protects both the fins  18  and  19  and the object from damage. 
     A control mechanism  28  controls the movement of the connecting rods  24  and  25  and is located within the core of the body board  10 . The control mechanism  28  comprises a shaft  29  having a T-head  30 . Each end of the T-head  30  is connected to a respective end of the connecting rods  24  and  25 . The connecting rods  24  and  25  are fully retracted when the T-head  30  is in a position substantially parallel to the side rails  13  and  14  and fully extended when the T-head  30  is in a position substantially perpendicular to the side rails  13  and  14 . 
     A control knob  31  is connected to the opposite end of the shaft  29  to the end having the T-head  30 . The control knob  31  is located external to the body board  10  adjacent the end rail  15 . 
     To retract or extend the fins  20  and  21 , the control knob  31  is rotated which causes simultaneously rotation of the shaft  29  and T-head  30 . This causes the connecting rods  24  and  25  to extend or retract which in turn retracts or extends the fins  20  and  21 . 
     The side fins  20  and  21  prevent the body board  10  from slipping down a face of the wave. The side fins  20  and  21  can be extended in small wave conditions to decrease the speed of the body board  10  across the wave and retracted in big wave conditions to increase the speed of the body board  10  across the wave. Retraction and extension of the fins  20  and  21  can increase the length of the ride and improve the performance of the body board  10 . Spinning tricks can also be performed easily with little or no interference from the fins  20  and  21 . 
     FIG. 3 and 4 show a fin unit  50  that is able to be mounted within a side rail of a body board. The fin unit comprises a fin  51  located within a housing  52 . A pin  53  is used to pivotally mount the fin  51  within the housing  52 . 
     The housing  52  is elongate and constructed from rigid plastics. A channel  54  is located within the housing  52  to allow the fin  51  to be totally retracted within the housing  52 . 
     Three sets of guides  55 ,  56  and  57  are located within the housing  52  to guide movement of the fin  51  within the housing  52 . Each set of guides  55 ,  56  and  57  has two guides  55 A and  55 B,  56 A and  56 B, and  57 A and  57 B located on opposite sides of the fin  51  to space the fin  51  from the housing  52 . This allows any sand that becomes lodged within the housing  52  to be easily dislodged, preventing jamming of the fin  51  within the housing  52 . 
     Stops  58 A and  58 B are located on the first set of guides  55 . Corresponding stop members  59  are located on each side of fin  51  to engage with the stops  58 A and  58 B. This prevents the fin  51  being extend past a desired position from within the housing  52 . 
     The fin  51  is biased outwardly from the housing by a spring  60  and is retained in a retracted position by a catch  61 . The catch  61  is pivotally mounted within the housing  52  by a pin  62  and is biased toward the fin by a spring  63 . The catch  61  can be retracted via a finger hole  64  to release the fin  51  to an extended position. 
     An edge  51 A of the fin  51  is stepped so that the catch can engage the fin  51  at different locations along the edge  51 A. This allows the fin  51  to be extended and held at discrete positions depending upon wave conditions. 
     The fin  51  is retracted within the housing  52  by pushing the fin  51  inwardly. This also prevents the fin  51  being damaged if knocked against an object as it will automatically retract. 
     It should be appreciated that various other changes and modifications may be made to the embodiment described without departing from the spirit or scope of the invention.