Abstract:
The present invention is directed to an improved support and lock for use in conjunction with a mobile sonar unit or other device. The improved support is rotatably coupled to the sonar unit base by a coupling assembly. A stabilizing member is slideably coupled to the distal end of the support via a locking assembly. Advantageously, the support maintains an object, such as a transducer, in a selected position and is able to resist deflection despite adverse environment conditions. Further, the disclosed locking assembly can be used for a wide variety of other applications.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. The Field of the Invention  
         [0002]     The present invention relates generally to sonar devices and, more particularly, the invention relates to a sonar device having a sonar transducer submerged in water extending from an arm supporting the transducer.  
         [0003]     2. Description of Related Art  
         [0004]     Over the last several decades, commercial and recreational fishermen alike have sought more effective tools to find and catch fish. One of the most effective tools to date has been sonar depth finder units. These units provide fishermen with a virtual picture of a local underwater environment. This picture, allows fishermen to determine if fish are actually present in the area, but perhaps more effectively, it allows fishermen to locate underwater structures where fish are known to congregate. As a result, fishermen may selectively fish over such areas thereby increasing their odds of success.  
         [0005]     Generally, fish finding units consist of a sonar display, a base for mounting the display, a sonar transducer, and an electrically conductive cable for electrically connecting the transducer to the sonar display. During use, the sonar transducer transmits ultrasonic signals that travel outwardly in a cone-shaped pattern, until striking the bottom of the body of water, submerged structures, or the fish themselves. Upon striking any of these objects, the ultrasonic signals are reflected, thereby creating echo signals that are received by the transducer. These signals are electrically transmitted to the display, which converts the echo signals into electronic signals. The electronic signals are used by the display to generate a visual representation of the local underwater environment.  
         [0006]     Conventionally, the fish finding units described above are mounted on fishing boats and are powered by the boat&#39;s onboard power source. The unit&#39;s transducers are generally mounted to the transom or hull of the boat. In many circumstances, however, the use of a sonar fish finder may be desired in environments that are not conducive to fishing from a boat. For example, fishermen may require use of a sonar depth finder when fishing in shallow channels, along river banks, from piers or when ice fishing. Accordingly, fish finding units operated in these environments cannot rely on a boat for power or structural support. In particular, such units must be mobile, self-contained, and capable of transmitting a directed sonar signal.  
         [0007]     In response, mobile fishing depth finder units have been developed according to the known prior art. Specifically, conventional mobile units have developed for use in ice fishing applications. These mobile ice fishing units consist of a sonar display, a base for mounting the display, a sonar transducer, a local energy source and an electrically conductive cable for mechanically supporting and electrically connecting the transducer to the sonar display. During fishing, the display is mounted to the base and positioned on a body of ice adjacent an ice fishing hole. The sonar transducer is placed within the hole such that the transducer is supported by the conductive cable below the ice. Accordingly, a “plumb-bob” configuration is produced wherein gravity acts to straighten the support cable thereby positioning the transducer substantially below the ice fishing hole.  
         [0008]     As conventional units are used more frequently, it has become apparent that they possess a number of significant drawbacks. For example, conventional units do not operate effectively in moving water. In particular, when a plumb-bob type transducer is deposited within a rapidly moving stream or provided in a body of water having underwater currents, the transducer is deflected off-line. As described above, it is important for an effective fisherman to know the location and orientation of the sonar transducer. This information allows the fisherman to ensure that the visual information provided by the sonar display, actually represents the targeted local underwater environment. Thus, if a transducer is deflected off-line by an underwater current or other similar body of moving water, the fish finding unit is left to undesirably describe an area that has not been targeted by the fisherman. Also, the fisherman is left largely unaware that the fish finder is not displaying the intended viewing area.  
         [0009]     Accordingly, it is desirable then to produce a fish finder unit having a transducer, which is securely supported in a known operating position either in standing or flowing water. Further, it is desirable to produce fish finder unit that is compact, mobile and easy to use. Finally, it is desirable to produce a fish finder unit having a transducer that may be quickly and easily deployed into a preferred viewing area beneath the water.  
       BRIEF SUMMARY OF THE INVENTION  
       [0010]     The present invention overcomes these and other limitations of the above-described prior art by providing a transducer support and associated lock for effective use with sonar units or other devices in a variety of environments. In particular, several embodiments of the present invention comprise a sonar unit having a display, a mounting platform or base, a transducer, a support, a stabilizing member, and a cable for electrically connecting the transducer and the display. A local energy source is provided to electrically power the sonar unit.  
         [0011]     According to one embodiment of the present invention, the support functions to carry the weight of the transducer during use. In another embodiment, the support includes proximate and distal ends. The stabilizing member is releasably attached to the distal end of the support via a locking assembly. In one embodiment, the stabilizing member supports the transducer during generation. The locking assembly comprises a lock configured to engage an internally threaded aperture provided at the distal end of the support. The lock comprises a body having a threaded exterior surface and opposed first and second ends. A bore for receiving the stabilizing member is provided within the body, extending longitudinally between the first and second ends. In one embodiment, the internally threaded aperture is tapered such that as the lock engages the internally threaded aperture in a screw-like manner the bore is constricted as the lock is drawn downwardly, thereby frictionally engaging the stabilizing member to remain “locked” in a desired position. In another embodiment, the lock itself is tapered and the internally threaded aperture is substantially cylindrical such that the first end of the lock is constricted as the lock is drawn downwardly, thereby constricting the bore and “locking” the stabilizing member in a desired position. In another embodiment, the support includes two curved lock retaining members that extend outwardly from the distal end of the support to define the threaded aperture. In one embodiment, the curved lock retaining members do not completely encircle the threaded aperture, thereby defining a slot.  
         [0012]     In another embodiment, the lock includes first and second interior surfaces that are structured within the lock body. The surfaces extend outwardly and radially from the bore to define an opening. According to one embodiment, the opening may be forced closed as the lock is drawn downwardly into the internally threaded aperture, thereby further constricting the bore and frictionally engaging the stabilizing member of the support. In another embodiment, the slot defined by the curved lock retaining members described above aligns with the opening defined within the lock to define a release position wherein the stabilizing member may be laterally released from the locking assembly.  
         [0013]     In another embodiment, the lock may further include a grip for facilitating tactile manipulation by a user. In one embodiment, the grip includes at least one radially extending flange. In another embodiment, the grip includes a plurality of detents. In still another embodiment, the grip may be omitted, and the lock may be rotated by a motor, actuator or other similar device.  
         [0014]     In another embodiment, the transducer may be rotatably coupled to the stabilizing member by a fastener. According to this embodiment, the fastener includes locked and unlocked positions such that the transducer is fixed relative to the stabilizing member in the locked position and free to rotate relative to the stabilizing member in the unlocked position. In another embodiment, the fastener includes a pin and nut configuration.  
         [0015]     In still another embodiment, the support is rotatably coupled to the base at its proximate end via a coupling assembly. The coupling assembly includes a coupler positioned at the proximate end of the support for engaging a receptacle provided within the base. The coupler includes a collar portion and a sleeve portion wherein the transition between the collar portion and the sleeve portion defines a downwardly directed toothed surface. The receptacle comprises an upwardly directed rim defining a bore through the base, wherein the rim includes an upwardly directed toothed surface. During use, the downwardly directed toothed surface of the coupler engages the upwardly directed toothed surface of the receptacle to hold the support in a desired position. In another embodiment of the present invention, the toothed portions of the coupler and receptacle may have rounded tooth surfaces such that the coupler may be disengaged from the receptacle without significant lifting force.  
         [0016]     Thus, there is provided an improved transducer support and associated lock having a more robust and durable design that is capable of assisting a user as they adjust the unit for use in different environments. Advantageously, the present invention provides a support and lock assembly for securing a transducer or other object at a desired vertical position regardless of the environment. For example, in sonar unit applications, the support and associated lock of the present invention is particularly useful when fishing in freshwater lakes or rivers from docks, boats, riverbanks, ice fishing, etc. Alternatively, the present invention may be used when saltwater fishing from shore, piers, or other similar structures. Essentially, the present invention is useful in all applications where a light-weight, portable fish finding unit is desired. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0017]     Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:  
         [0018]      FIG. 1  is a perspective view of a sonar unit in accordance with one embodiment of the present invention;  
         [0019]      FIG. 2  is an enlarged partially exploded view of a transducer support arm in accordance with one embodiment of the present invention;  
         [0020]      FIG. 3A  is section view of a locking assembly, taken along section line  3 - 3  of  FIG. 1 , in accordance with one embodiment of the present invention;  
         [0021]      FIG. 3B  is section view of a locking assembly, taken along section line  3 - 3  of  FIG. 1 , in accordance with one embodiment of the present invention;  
         [0022]      FIG. 3C  is section view of a locking assembly, taken along section line  3 - 3  of  FIG. 1 , in accordance with one embodiment of the present invention;  
         [0023]      FIG. 4  is a detail view of a lock according to one embodiment of the present invention;  
         [0024]      FIG. 5  is an exploded view of a locking assembly, according to another embodiment of the present invention;  
         [0025]      FIG. 6A and 6B  are top views of a locking assembly according to the embodiment depicted in  FIG. 5 , wherein  FIG. 6A  depicts the locking assembly in a fixed position and  FIG. 6B  depicts the locking assembly in a released position; and  
         [0026]      FIG. 7  illustrates a support having a coupling assembly according to one embodiment of the invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]     The present inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.  
         [0028]     The present invention is directed to a support for a transducer or other object that provides improved stability and durability. Although the present application periodically makes reference to sonar units and specifically to sonar ice fishing units, the present invention is not limited to such applications and instead such references are provided merely to illustrate the durability and accuracy of the support structure. The present invention and the inventive concepts herein may be applied to support structures used in any environment where it is advantageous to accurately position an object (e.g., a transducer, etc.) a distance from the support structure.  
         [0029]      FIG. 1  illustrates a perspective view of a sonar unit  100  in accordance with one embodiment of the present invention. According to the depicted embodiment, the sonar unit  100  comprises a control/display unit  120 , a mounting platform or base  130 , a transducer  150 , a support  160 , a stabilizing member  166  and a cable  140  for electrically connecting the transducer  150  and the control/display unit  120 . A local energy source  125  is provided to electrically power the sonar unit  100 . In addition, the embodiment illustrated by  FIG. 1  also includes a locking assembly  200  and a coupling assembly  300  for providing improved structural support to a submerged transducer  150 , as will be described in further detail below.  
         [0030]     According to one embodiment of the present invention, the base  130  is placed on a surface adjacent a body of water having a preferred viewing area, i.e., the area of the water to be scanned. For example, the base  130  may be placed on an ice surface adjacent an ice fishing hole during winter or on a dock adjacent a lake during summer months. The control/display  120  and its associated local energy source  125  are mounted to the base  130  and electrically connected to a transducer  150  via a conductive cable  140 . A support  160  carries the weight of the transducer  150  and further allows manipulation of the transducer&#39;s horizontal position during use. The support  160  includes proximate  162  and distal  163  ends. In one embodiment, the support  160  is rotatably coupled to the base  130  at its proximate end  162  via a coupling assembly  300 . According to the embodiment depicted in  FIG. 1 , a stabilizing member  166  is releasably attached to the distal end  163  of the support  160  so as to carry the weight of the transducer  150  and provide horizontal stability to the transducer  150  during use. According to various embodiments of the present invention, the claimed stabilizing member  166  may include a rigid or semi-flexible rod (as shown) or other similar support device as will be apparent to one of ordinary skill in the art.  
         [0031]     According to one embodiment, the transducer  150  is properly positioned within a preferred viewing area by physical manipulation of the unit by a user. Generally, the preferred viewing area, e.g., an area in the water to be scanned with sonar, is an area adjacent the sonar unit  100 , such as, in ice fishing applications, an ice fishing hole. In other applications, the preferred viewing area may be the water immediately adjacent a boat, dock or pier, etc. In non-sonar applications this area may simply be an area generally remote from the base  130 . According to the depicted embodiment, the transducer  150  is positioned over the viewing area by swinging the support  160  outwardly. The stabilizing member  166  (and attached transducer  150 ) may then be lowered into the preferred viewing area as described below.  
         [0032]     In this regard, the stabilizing member  166  includes a length defined by opposed ends  186 ,  187 . In one embodiment, the stabilizing member  166  is releasably coupled to the distal end  163  of the support  160  via a locking assembly  200 . In another embodiment, the transducer  150  is pivotally attached to a first opposed end  187  of the stabilizing member  166  by a fastener  180  as shown. Accordingly, the first opposed end  187  of the stabilizing member  166  (and attached transducer  150 ) may be lowered into the preferred viewing area by releasing the locking assembly  200 . As will be apparent to one of ordinary skill in the art, the length of the stabilizing member  166  may relate to the range of viewing depths that are available for the transducer  150 .  
         [0033]      FIG. 2  illustrates a partially exploded view of the support  160 , the transducer  150 , the stabilizing member  166 , and the locking assembly  200  in accordance with one embodiment of the present invention. As described in greater detail below with regard to  FIG. 3 , the locking assembly  200  includes a lock  205  having a threaded exterior surface  220  and an internally threaded aperture  169  positioned within the distal end  163  of the support  160  as shown. The internally threaded aperture  169  is configured to receive the lock  205 . In one embodiment, the locking assembly  200  functions to provide selective vertical positioning of the stabilizing member  166  and the transducer  150 . In other embodiments, the locking assembly  200  may provide selective positioning of various other objects (not shown). In those embodiments having a transducer  150 , an electrically conductive cable  140  is also provided to electrically connect the transducer  150  and sonar control/display unit  120 . Alternatively, in other embodiments, the transducer  150  may be wirelessly connected to the control/display (not shown) via Bluetooth, RF signal communication or other wireless communication or other similar techniques as known to one of ordinary skill in the art.  
         [0034]     In various embodiments of the invention, a bore  260  is provided that extends through the lock  205  for receiving the stabilizing member  166 . In one embodiment, as described below, the bore  260  is capable of constricting the stabilizing member  166  to define “locked” and “unlocked” positions. When “locked,” the stabilizing member  166  is restricted from translating vertically due to frictional forces between the bore  260  and the stabilizing member  166 . In the “unlocked” position, the stabilizing member  166  is slidable relative to the lock  205  and, thus, the stabilizing member  166  and attached transducer  150  may be adjusted between depths within the viewing area for more effective use. According to the depicted embodiment, the lock  205  may be actuated between locked and unlocked positions by rotating or twisting. As will be apparent to one of skill in the art, such movements allow the threads on the exterior of the lock to engage the internally threaded aperture  169  of the support  160 . In one embodiment, the lock  205  is rotated by the physical manipulation of a user. In other embodiments, the rotation of the lock  205  is automated and performed by a motor, actuator or other similar means.  
         [0035]     According to the embodiment illustrated in  FIG. 2 , other components cooperate to support the transducer  150 . In one embodiment, a fastener  180  may be provided to pivotally couple the transducer  150  to a first opposed end  187  of the stabilizing member  166 . According to the depicted embodiment, the fastener  180  includes a pin  181  configured to engage a nut  182 . The pin  181  includes proximate  183  and distal  184  ends. The proximate end  183  of the pin  181  is attached or integral to the first opposed end  187  of the stabilizing member  166 . In one embodiment, the transducer  150  defines upper  141  and lower  142  ends, and includes a bore  145  that extends laterally through its upper end  141 . The bore  145  is configured to receive the pin  181  such that it may be engaged and held by the nut  182  as shown. Accordingly, the transducer  150  may be fixed in a locked angular position as apparent to one of skill in the art. In the locked position, the transducer  150  is prevented from rotating. By loosening the nut  182  the transducer  150  may be returned to an unlocked position wherein the transducer  150  is freely rotatable.  
         [0036]     Although depicted as comprising a pin and nut configuration, various embodiments of the invention may include fasteners  180  of other configurations known in the art. It is noted, that by pivotally coupling the transducer  150  to a stabilizing member  166 , such as a vertically oriented rod, tube, etc., the present invention provides enhanced versatility for transducer imaging. For example, in calm water, the transducer  150  may be secured loosely by the depicted fastener  180 , perhaps by loosening the nut  182  as described above and, thus, gravity is allowed to direct the transducer  150  downwardly producing a substantially vertical sonar-sensing cone. In other environments having moving water or currents, a more structured support may be needed to prevent the transducer  150  from being knocked off-line. Accordingly, the transducer fastener  180  may be tightened, thereby allowing the stabilizing member  166  or rod to resist the force applied to the transducer  150  by the current or other external force. Finally, in another embodiment, a side-scanning functionality is provided. In particular, a user may simply direct the transducer  150  laterally to a desired sensing angle and tighten the fastener  180  to lock the unit in place.  
         [0037]      FIGS. 3A-3C  provide a detailed section view of a locking assembly  200 , in accordance with one embodiment of the present invention. Regarding  FIG. 3A , a lock  205  is depicted for facilitating the selective vertical positioning of the stabilizing member  166  relative to the support  160 . According to the depicted embodiment, the lock  205  includes a lock body  210  having a circular cross-section and a threaded external surface  220 . The lock  205  is configured to rotatably engage a similarly shaped internally threaded aperture  169 . As referenced above, the internally threaded aperture  169  is defined by the distal end  163  of the support  160 . In addition to its threaded exterior surface  220 , the lock body  210  includes opposing first  230  and second  240  ends as shown. A bore  260  for slidably receiving the stabilizing member  166  is provided through the lock body  210 , extending between its first  230  and second  240  ends.  
         [0038]     It is noted, that although  FIGS. 1-6  depict the lock  205  and the associated internally threaded aperture  169  as having a substantially cylindrical shape, the present invention is not limited to such a configuration. In fact, the lock  205  and internally threaded aperture  169  may comprise any shape having a circular cross-section (e.g., cylindrical, conical, frusto-conical, funnel-shaped, and the like) so long as they are configured to rotatably engage one another.  
         [0039]     In one embodiment, the lock  205  further includes a grip  250  disposed at the first end  230  of the lock body  210 . The grip  250  provides a tactile gripping surface for users to manipulate when adjusting the position of the stabilizing member  166  and attached transducer  150  (not shown). According to the depicted embodiment, the grip  250  includes at least one radially extending flange  252 . Accordingly, a user is afforded proper leverage so as to provide effective rotation force to the lock  205 . In other embodiments, the grip  250  may include a series of detents (not shown) or other similar tactile gripping means as known to one of ordinary skill in the art. In automated embodiments as described above, where the rotation of the lock is controlled by a motor or other device, the grip  205  may be optionally omitted and replaced with teeth, gears or other structures for engaging the motor.  
         [0040]     In another embodiment of the present invention, at least a portion of the lock  205  is comprised of a thermoplastic elastomer. Advantageously, according to this embodiment the lock  205  effectively maintains its shape in hot and cold temperatures. In other embodiments, other polymers, rubbers, composites, or the like may be selected to completely or partially comprise the lock  205  as known to one of ordinary skill in the art.  
         [0041]     According to the embodiments illustrated in  FIGS. 3B and 3C , the threaded external surface  220  of the lock body  210  rotatably engages the internally threaded aperture  169  of the support  165 . Although the threaded external surface  220  of the lock body  210  and the internally threaded aperture  169  are depicted as having a male/female thread configuration respectively; other embodiments of the present invention may have the opposite thread configuration (e.g., the lock body may have female threads and the internally threaded aperture may have male threads) as known to one of ordinary skill in the art.  
         [0042]     According to the depicted embodiment, the lock  205  operates by rotation. In particular, a user engages the internally threaded aperture  169  by grasping and rotating the lock  205  in a screw-like manner. As a result, the lock  205  is drawn downwardly into the internally threaded aperture  169 . According to one embodiment, the internally threaded aperture  169  includes entrance  190  and exit  191  ends and is at least partially tapered such that the diameter  195 ′ of the aperture  169  at the entrance end  190  is greater than the diameter  195 ″ of the aperture  169  at the exit end  191 . Accordingly, as the lock  205  translates downwardly within the aperture  169 , an inwardly directed force “F” is applied to the lock body  210  as shown. The inwardly directed force “F” is transmitted through the lock body  210  and applied to the bore  260 . As a result, downward translation by the lock  205  produces a constriction of the bore  260 , thereby frictionally engaging the stabilizing member  166  to remain in place. Accordingly, the lock  205  is thereby engaged from an “unlocked” to a “locked” position.  
         [0043]     In other embodiments, the lock body  210  and internally threaded aperture  169  may be oppositely tapered. Specifically, the lock body  210  may be tapered to have a larger first end  230  and a smaller second end  240  while the internally threaded aperture  169  may possess a substantially cylindrical shape (not shown). As described above, rotation of the lock  205  draws the lock body  210  downwardly into the aperture  169  and simultaneously produces an inwardly directed force “F” as shown. In the depicted embodiment, the inwardly directed force “F” is produced by the internally threaded aperture&#39;s  169  resistance to accepting the larger first end  230  of the lock body  210 . The inwardly directed force “F” compresses the lock body  210 , thus, constricting the bore  260  and locking the stabilizing member  166  in place.  
         [0044]     In another embodiment, as illustrated in  FIG. 4 , an opening  400  may be defined within the lock body  210  to facilitate further constriction of the bore  260  around the stabilizing member (not shown). The opening  400  is configured longitudinally between the first  230  and second  240  ends of the lock body  210  as shown. The opening  400  is defined by first  410  and second  420  interior surfaces, which extend radially and outwardly from the bore  260  as shown. As is apparent, locks having such openings possess a substantially c-shaped body, wherein the bore  260  and opening  400  define the open part of the “C.” When such c-shaped locks  205  are engaged into the threaded aperture  169  as described above, the lock opening  400  is gradually forced closed by the tapered locking assembly configurations described above. Accordingly, when rotated downwardly into the threaded aperture (not shown), the diameter of the bore  430  is reduced to a constricted diameter  430 ′ as shown.  
         [0045]      FIGS. 5 and 6  illustrate a partially exploded locking assembly  500  for optionally retaining a stabilizing member  566  in a fixed vertical position in accordance with another embodiment of the present invention. In the depicted embodiment, the locking assembly  500  comprises a lock  505  having an opening as described above that is configured in rotating engagement with a threaded aperture  669  of a particular design. In the depicted embodiment, the threaded aperture  669  is defined by first and second lock retaining members  670 ,  671  that extend outwardly from the distal end  663  of the support  660  as shown in  FIG. 5 . In one embodiment, the first and second locking retaining members  670 ,  671  do not completely encircle the threaded aperture  669 , thus defining a slot  664  as shown. In one embodiment, the slot  664  (and the opening defined by the lock) are sufficiently sized to accommodate direct removal of a vertically aligned stabilizing member  566 . Accordingly, in one embodiment, the opening of the lock (not shown) and the slot  664  defined by the first and second lock retaining members  670 ,  671  of the support  660  may be configured relative to one another so as to define fixed and released positions. In one embodiment, as shown in  FIG. 6A , the opening  900  of the lock  505  and the slot  664  defined by the first and second lock retaining members  670 ,  671  may be at least partially misaligned to define a fixed position. In the fixed position, a vertically aligned stabilizing member  566  may not be removed laterally as shown. In another embodiment, as shown in  FIG. 6B , the opening  900  of the lock  505  and the slot  664  defined by the first and second lock retaining member are aligned as shown, thereby allowing lateral removal of a vertically aligned stabilizing member  566 . In various embodiments of the present invention, the locking assembly  500  is configured between fixed and released positions by rotating the lock  505  within the threaded aperture  669  as will be apparent to one of ordinary skill in the art in view of the above disclosure.  
         [0046]      FIG. 7  illustrates yet another embodiment of the present invention. In particular, a coupling assembly  300  is illustrated for rotatably coupling the support  160  to the base  130 . The coupling assembly  300  comprises a coupler  305  and a receptacle  330  that are configured to rotatably engage one another. The coupler  305  is disposed at the proximate end  162  of the support  160  and includes a collar portion  320  and sleeve  310  portion. A transition region  315  is defined between the collar portion  320  and the sleeve portion  310 . According to one embodiment, the transition region  315  defines a downwardly directed toothed surface  325 .  
         [0047]     According to the depicted embodiment, the receptacle  330  is disposed on the base  130  and includes a rim  340  that defines a bore  350 . The rim  340  further includes an upwardly directed toothed surface  345  for engaging the downwardly directed toothed surface  325  of the transition region  315  of the coupler  305 . During use, the sleeve portion  310  of the coupler  205  is deposited within the bore  350  defined by the rim  340  of the receptacle  330 . Thus, the downwardly directed toothed surface  325  of the collar  320  is brought into contact, thereby engaging the upwardly directed toothed surface  345  of the rim  340 . Accordingly, a set position is thereby defined wherein the support  160  is prevented from rotating relative to the base  130 . A free position is achieved by slightly lifting the support  160  such that the sleeve slides upwardly within the bore  350  to disengage the downwardly directed toothed surface  325  of the collar  320  from the upwardly directed toothed surface  345  of the rim  340 . In the free position, the support  160  may freely rotate relative to the base  130 .  
         [0048]     In various other embodiments, a locking fastener (not shown) may be provided to place a downwardly directed force on the coupler  305 , thus, preventing the coupler  305  from disengaging the receptacle  330  and precluding rotational movement. Such a locking fastener may be used to prevent the transducer from being knocked out of position within the preferred viewing area should the fishermen bump or otherwise inadvertently contact the fish finding unit. The locking fastener may include a threaded clamp positioned through the center of the coupler or be applied externally as known to one of ordinary skill in the art.  
         [0049]     Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.