Abstract:
A shallow water anchor system provides a single arm arrangement with a fixed end of the arm mounted to the transom of a boat and the distal end of the arm retaining a rod adapted to be buried into the bottom of a lake, estuary, or other shallow body of water. The fixed end of the arm includes a first sheave and the distal end of the arm includes a second sheave, with a cable under tension between the first and second sheaves. A hydraulic operating mechanism drives a sliding block clamped to the cable. A hydraulic pressure is applied to one side of the other of a hydraulic piston with a cylinder to drive the operating mechanism, the sliding block moves back and forth thereby moving the arm up and down in a rotary motion about a shaft on the fixed end of the arm. In the down position, the rod is embedded into the bottom. In the stowed position, the arm is oriented straight up in a vertical position.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61/068,087 filed Mar. 5, 2008. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of anchoring devices for marine vessels, and, in particular, to an articulated anchor system adapted to hold a small boat in a stationary position in shallow water. 
       BACKGROUND OF THE INVENTION 
       [0003]    Along many coastal areas of the United States, and in certain lakes and estuaries, fishermen fish from small boats in shallow water. In these types of fishing areas, there are extensive shallow, sandy-bottomed or grassy-bottomed regions, generally referred to as flats, that are populated by various sport fish. Fishermen who fish these flats often use one or another of several methods of holding a boat at a selected location. These methods include the use of conventional anchors, the use of a pole shoved into the bottom and secured to the boat, or other methods. 
         [0004]    As described by Oliverio et al. in U.S. Pat. No. 6,041,730, the use of anchors such as a Danforth or a similar type of anchor by flats fishermen has several shortcomings. First, such types of anchor do not firmly fix the position of the boat so that the boat can may drift at the end of the anchor line. Second, when setting and retrieving an anchor, the anchor&#39;s flukes may rip sea grass out of the bottom and cause ecological damage. Finally, when the anchor is hauled in, mud and sea grass from the anchor can foul the inside of the boat. 
         [0005]    Other means of securing a boat in shallow water include a pole-like structure to which the both may be secured. In addition to Oliverio et al., other references dealing with similar means include U.S. Pat. No. 458,473 wherein MacDonald describes a jointed structure hinged to a submersible coastal artillery battery and comprising a pole inserted into the bottom of a shallow body of water. Other elongate pole-like anchoring mechanisms not hingedly secured to a vessel are taught by Mestas et al. in U.S. Pat. No. 4,960,064 and by Stokes in U.S. Pat. No. 4,702,047. Mechanisms other than anchors that are hingedly attached to a vessel hull are taught, inter alia, by Alexander, in U.S. Pat. No. 2,816,521 and by Sherrill in U.S. Pat. No. 3,046,928, both of whom show stem stabilizers, and by Doerffer, in U.S. Pat. No. 4,237,808, who shows a braking device. 
         [0006]    Unfortunately, the structure of Oliverio et al. requires an upper arm and a lower arm which together form a parallelogram, with one side of the parallelogram anchored to the transom of the boat, and the opposite side of the parallelogram retaining a rigidly fixed anchor pole. With this structure, the total range of movement of the mechanism is by necessity approximately 150°. This severely limits the depth at which the anchor may be effectively used. Further, this structure is heavy, due in large part to the number of structure elements which are required in order for the anchor to properly function. Finally, the structure shown and described in Oliverio et al. is rigidly dictated in the mounting of the parallelogram to the transom of the boat. In order to adapt the mounting of the structure to a boat with any slant other than that predetermined by the structure requires shims and adapter plates to arrange the anchor pole to the proper deployed position. 
         [0007]    Thus, there remains a need for a shallow water anchor that provide a range of movement of 180°, or even more, to maximize the effect depth of the anchor. The anchor should preferably be light-weight to make the anchor easier to use and make the most of the prime mover of the mechanism. The mounting structure of the apparatus should also easily adapt the mount to any reasonable slant of the transom relative to the surface of the water. The present invention is directed to filling that need in the art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    The shallow water anchor shown and described below solves these and other drawbacks of known anchor systems by providing a single arm arrangement with a fixed end of the arm mounted to the transom of a boat and the distal end of the arm retaining a rod adapted to be buried into the bottom of a lake, estuary, or other shallow body of water. The fixed end of the arm includes a first sheave and the distal end of the arm includes a second sheave, with a cable under tension between the first and second sheaves. A hydraulic operating mechanism drives a sliding block clamped to the cable. A hydraulic pressure is applied to one side or the other of a hydraulic piston with a cylinder to drive the operating mechanism, the sliding block moves back and forth thereby moving the arm up and down in a rotary motion about a shaft on the fixed end of the arm. In the down position, the rod is embedded into the bottom. In the stowed position, the arm is oriented straight up in a vertical position. 
         [0009]    By providing a single arm for retaining the rod, the entire mechanism can be made much lighter. This also means that the hydraulic means can be much more efficiently used. Further, by using the cable and sheave arrangement, a much shorter hydraulic cylinder stroke is required to move the arm, which results in a faster deployment of the rod (3 seconds vs. 6 seconds for known anchor systems). The mounting system for the fixed end of the arm provides for an adjustment, so that the system can be easily mounted to various angles of transom for boats without any shims of adapting brackets. A shear pin is provided for the outer sheave to reduce the likelihood of damages to the rod if the boat should be underway with the rod deployed. A spring-loaded flexible subsystem for the arm may be used, to help keep the boat in place when the boat is subjected to wave action. 
         [0010]    These and other features and advantages of this invention will be readily apparent to those skilled in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, more particular description of the invention, briefly summarized above, may be had by reference to embodiments thereof which are illustrated in the appended drawings. 
           [0012]      FIG. 1  is a side, elevation view showing the anchor in several positions. 
           [0013]      FIG. 2  is a sectional side view of the presently preferred embodiment of the anchor in a horizontal position. 
           [0014]      FIG. 2A  is a detail side view of a sliding block portion of  FIG. 2 . 
           [0015]      FIG. 3  is a sectional top view as indicated by section lines  3 - 3  in  FIG. 2   
           [0016]      FIG. 4  is a sectional side view showing the device in a partially raised position. 
           [0017]      FIG. 5  is a sectional top detail view as indicated by section lines  5 - 5  in  FIG. 6 , showing the fixed end of the main arm in more detail. 
           [0018]      FIG. 6  is a sectional side detail view as indicated by section lines  6 - 6  in  FIG. 5 . 
           [0019]      FIG. 7  is a sectional top view as indicated by section lines  7 - 7  in  FIG. 8 , showing the distal end of the main arm in more detail. 
           [0020]      FIG. 8  is a sectional detail view as indicated by section lines  8 - 8  in  FIG. 7 . 
           [0021]      FIG. 9  is side view of another presently preferred embodiment of the device in a partially deployed position. 
           [0022]      FIG. 10  is a side view of the embodiment of  FIG. 9  in a deployed position. 
           [0023]      FIG. 11  is a side section view showing details of the function of the embodiment of  FIG. 9 . 
           [0024]      FIG. 12  is a side section view showing details of the function of the embodiment of  FIG. 9  in choppy water. 
           [0025]      FIG. 13  is side section view of a parallelogram embodiment, modified with the improvement of  FIG. 9 . 
           [0026]      FIG. 14  is a top section detail view of a presently preferred distal end of the device. 
           [0027]      FIG. 15  is a side detail view of the embodiment of  FIG. 14 . 
           [0028]      FIG. 16  is a side detail view of the embodiment of  FIG. 14  in a different position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]      FIG. 1  illustrates shallow anchor system constructed in accordance with the teachings of this invention. The system includes a main arm  10  which is rotatably attached by a fixed end  20  to a mounting bracket  12 . The mounting bracket  12  in turn is fixedly attached to a transom  14  of a fishing boat  16 . By a power mechanism, preferably a hydraulic means as described below, the arm  10  is rotated into various positions such as A, B, and C, for example. When the arm is in position A, the anchor system is in the stowed position, as it would be when not in use, such as for example while the boat is under powered motion. Position B of the arm is an intermediate position, for illustration purposes extending horizontally. When the arm  10  is in position C, the arm is partially lowered to a deployed orientation. 
         [0030]    Opposite the fixed end  20  of the arm  10  is a distal end  22 . A rod  18  which is rotatably connected to the distal end  22  of the arm  10  in a manner to maintain a vertical orientation for the rod  18  in all positions of the arm  10 , described below in greater detail. The rod  18  is driven into the bottom  24  of the lake or other body of water, thereby anchoring the boat  16  at a location dictated by the operator. 
         [0031]      FIGS. 2 and 3  illustrate certain details of the preferred structure of the arm  10  and its mounting. Referring first to the fixed end  20  of the arm  10 , the bracket  12  (see  FIG. 1 ) includes a base plate  26 , which is fixed to the transom  14  of the boat  16 , such as for example by bolts or other fixing means. A pair of parallel forks  28  extend outwardly from the base plate a distance sufficient to receive a shaft  30 . The shaft  30  is clamped to the forks  28  by retainers  32  so that the shaft  30  remains in a fixed relation to the bracket  12 , i.e., the shaft  30  does not rotate relative to the forks  28 . A first cable sheave  34  is mounted on the shaft  30  and also pinned to the shaft so that it cannot rotate. However, rotation of the arm  10  to the various positions shown in  FIG. 1  is provided by the mounting of a tubular member  36  to the shaft  30  (see also  FIGS. 5 and 6 ). 
         [0032]    Referring now to the distal end  22  of the arm  10 , a second cable sheave  38  is rotatably mounted to the tubular member  36 . The second sheave  38  is of the same diameter as the sheave  34 . A cable  42  is slung around the sheaves  34  and  38 . Pairs of idling sheaves  40 , one pair at the fixed end  20  and one pair at the distal end  22 , direct the cable  42  into the inside of tubular member  36 . Sleeves  44 , one sleeve at each end of the arm  10 , are swaged onto the cable  42 . Each sleeve  44  is nestled inside a notch  46  of its respective sheave  34  or  38  to prevent the cable  42  from slipping relative to the sheave. Tension to the cable  42  is preferably applied by a mechanism as described below in reference to  FIG. 7 and 8 . 
         [0033]    A sliding block  50  is positioned inside the tubular member  36 . The sliding block  50  is preferably attached to the cable  42  by means of a clamp  52  or other appropriate means. Note, however, that the sliding block  50  defines a through-passage  59  through which the cable return passes without obstruction. In this way, movement of the sliding block in one direction pulls the cable at the clamp  52  in that direction. The tubular member  36  includes an opening  54  to provide access to the clamp  52  for assembly and repair of the device. 
         [0034]    A hydraulic cylinder mechanism  55  is mounted with its cylinder end  56  coupled to the tubular member  36 . A piston rod  72  (see  FIG. 4 ) extends from the mechanism  55  and terminates at a rod end  58  which is coupled to one side of the sliding block  50 . A tension spring  60  is attached to the other side of sliding block  50  at one end of the spring  60  and to a fixed point of the tubular member  36  adjacent the distal end  22  of the arm. The tension of the spring  60  is sufficient to hold the arm  10  in a horizontal position, shown as position B in  FIG. 2 . 
         [0035]    To move the arm to the various positions shown in  FIG. 1 , the hydraulic cylinder mechanism  55  is actuated. In other words, when hydraulic pressure is applied to the piston of the cylinder  55 , the rod  72  moves to the right, thereby forcing the sliding block  50  to the right as well, as viewed in  FIG. 2 . This motion of the sliding block pulls the cable around the sheaves  34  and  38  in a clockwise direction, thus causing the arm  10  to rotate counter-clockwise around sheave  34 , assisted by the tension of the spring  60 . Hydraulic pressure to the other side of the cylinder piston  55  causes the sliding block  50  to be forced to the left, thus causing arm  10  to rotate clockwise, or downward, moving the rod  18  toward engagement with the lake bottom  24 . 
         [0036]    A bracket  70  is attached to the sheave  38  to hold rod  18  in a fixed relation to the sheave  38 . Since the sheaves  34  and  38  are connected by the cable  42 , and the sheave  34  cannot rotate, the sheave  38  also will not rotate, as the arm  10  moves up or down by rotating around the shaft  30 . Thus, since the sheave  38  does not rotate, the bracket  70  also does not rotate and the rod  18  will always maintain its vertical orientation. 
         [0037]      FIG. 4  shows the anchor mechanism partially raised or rotated counter-clockwise around shaft  30 . The cylinder rod  72  has been extended in a direction indicated by the number  74 , pushing the sliding block  50  to the right, assisted by contracting the spring  60 , thus lifting the arm  10  up and pulling the rod  18  away from the lake bottom. 
         [0038]      FIGS. 5 and 6  illustrate more details of the fixed end  20  of the arm  10 . The shaft  30  defines knurled ends ( 78 ), where the shaft  30  is engaged by the clamps  32 , to retain the shaft  30  in locking engagement with the forks  28  of the mounting bracket  12 . The locking engagement of the shaft is assisted by a pair of set-screws  80 . The sheave  34  is connected to the shaft  30  by a pin  82  so that the sheave  34  is prevented from rotating as arm  10  rotates up or down. This arrangement allows an angle a (see  FIG. 2 ) to be adjusted according to the angle of the boat transom, against which the mounting plate must be mounted. The angle a is adjusted by loosening the clamps  32  (including the set screws  80 ), rotating the arm  10  into a perfectly vertical position A (as shown in  FIG. 1 ) while the cylinder rod  72  is completely extended, and re-tightening the clamps  32  and set-screws  80 . 
         [0039]      FIGS. 7 and 8  show the distal end  22  of the arm  10  in more detail, specifically the tensioning means for the cable  42 . The sheave  38  rotates relative to a shaft  90 . Outer ends  92  of the shaft  90  extend into a pair of opposing plates  94 , which are slidably held inside the tubular member ( 36 ). Bridge bars  96  rest against the open ends  98  of the tubular member  36  and provide a fixed base toward which the opposing plates  94  can be pulled by a set of bolts  100 . The bolts screw into the opposing plates  94  and as the bolts are turned in a clockwise direction, the plates are moved to the right as seen in  FIGS. 7 And 8 , thus forcing the shaft  90  and therefore the sheave  38  to the right and increasing tension of the cable  42 . 
         [0040]    As previously described, a cable is preferably used as the connecting means between sheaves  34  and  38  for economic reasons; however a much more expensive arrangement consisting of chain and sprockets is also possible, expensive because of the environment in which this anchor will be used, all materials used must non-corroding, like aluminum, stainless steel, bronze and plastic. Thus, as used herein, the term “continuous loop of material” refers to a cable, a chain, or other means of engaging the sheaves  34  and  38 . The cable  42  shown in  FIG. 2  is continuous, even thought it is preferably constructed of cable cut to length, and formed into a loop by a joining member  43 . 
         [0041]    The anchor system thus far described and as shown in  FIG. 1  thru  8  works well in calm water. When there is wave action though, the rod  18  may be pulled out of the bottom  24  by waves lifting up boat  16  to which the anchor is attached. While this problem cannot be completely eliminated, such as when the boat is in a storm, the problem can be alleviated by the embodiment illustrated in  FIGS. 9 to 12 . This embodiment provides a flexible connection between piston rod  72  and the cable  42 . The piston rod  72  is extended beyond and through the sliding block  50  and the rod is provided with collars  106  and  108 . A compression spring  110  is placed between the collar  108  and sliding block  50 . 
         [0042]    In  FIG. 9 , the rod  72  from the cylinder  55  is  50 % extended so the tubular member  36  is in a horizontal position. In this position, the compression spring  110  is partially compressed. To lower the anchor to a position as shown in  FIG. 10  where the rod  18  is embedded into the bottom  24 , the piston rod  72  is further retracted into the cylinder  55 , the sliding block  50  is moved and has pulled on the cable  42  to rotate the arm  10  clockwise around sheave  34 . Continued supply of hydraulic fluid to the cylinder  55  forces the rod  72  to retract further until the collar  106  reaches its end position against the cylinder  55 , as illustrated in  FIG. 11 . While the sliding block  50  is unable to move, and thus sheave  34  is also held in place, the arm  10  rotates clockwise and maintains contact with bottom  24  through the compression spring  110  being compressed between the collar  108  and the block  50 . 
         [0043]      FIG. 12  illustrates conditions where wave action lowers boat  16  but the rod  18  is stuck in the ground so it cannot go any lower. Under those conditions, the anchor  10  must rotate counter-clockwise around the sheave  34 , which reduces the distance between the block  50  and the collar  108 , compressing the spring  110  even more. When wave action causes the boat  16  to rise, the stored energy in the spring  110  pushes the block  50  toward the distal end of the arm. 
         [0044]    This feature of the present invention may also be applied to known structures, as shown in  FIG. 13 .  FIG. 13  illustrates an anchor using a parallelogram  118  of links to maintain a vertical position of a ground-engaging rod  120 . The motion of the rod  120  is caused by a cylinder  122 , which changes the distance D between opposing pivot points  124  and  126 . When the rod  120  has engaged the bottom  130  and the parallelogram  118  has reached a fixed configuration, energy can be stored in a spring  128  by further retracting a piston rod  132  and compressing the spring  128 . This energy can be used to reduce the distance D, thus pushing the rod  120  down when wave action lifts boat  134  up. 
         [0045]    A common mishap occurs when anglers leave an anchor deployed with a rod embedded into the bottom  24  and set their boat into motion. With enough force, the rod stuck in the bottom may break, or the bracket mounting the rod may be damaged. The embodiment of  FIGS. 14-16  solves this problem by changing the way the rod  18  is mounted to the sheave  38 . 
         [0046]    In this embodiment, extensions  150  are attached to the sheave  38 , holding a bracket  152  in between by a bolt  154  and a shear pin  156 . As the boat and anchor start moving and the rod  18  is still embedded in the ground (as shown in  FIG. 16 ), the shear pin  156  shears off to allow the bracket  152  to rotate around the bolt  154 . This motion alters the angle at which the rod is set in the bottom until the rod pulls free from the bottom, thus saving the rod  18  from breaking. 
         [0047]    The principles, preferred embodiment, and mode of operation of the present invention have been described in the foregoing specification. This invention is not to be construed as limited to the particular forms disclosed, since these are regarded as illustrative rather than restrictive. Moreover, variations and changes may be made by those skilled in the art without departing from the spirit of the invention.