Abstract:
A lift for a watercraft has plastic reinforcing brackets which engage in pockets in the thin-walled plastic floatation tanks of the lift and which provide mounting flanges at the top surfaces of the floatation tanks for abutment with mounting pads which connect to the watercraft support frame. The brackets are engaged on the floatation tanks and the pads overlap and are bolted to the plastic brackets, so that the pads are locked against but not bolted to the floatation tanks. Thus, the integrity of the tanks is not compromised by assembly-associated openings through the tank walls. Furthermore, the bolts are above the tank waterlines so that no corrosive material is disposed below the waterlines.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates generally to watercraft lifts and more particularly concerns the structural components connecting the lift floatation tanks to the watercraft support frame. 
   In connecting lift floatation tanks to a watercraft support frame, the frame is fixed to the floatation tanks by bolts through flanges on the tanks, by metal belts tautly pulled around the cross-sections of the tanks or by use of welded assemblies of metal tubes and brackets with the tubes fitted into grooves in the sidewalls of the tanks. The bolts, surrounding belts and side mounted tube assemblies are continuously exposed to water. The integrity of the tank is eventually compromised by the reciprocating forces exerted at the bolt holes on the tank plastic while the lift is in use. The connections to the frame are typically located proximate the front and rear ends of the tanks. As a result, the weight of the watercraft is applied to the front and rear ends of the floatation tanks. The buoyancy force of the water, however, is applied to the entire length of the tanks. Therefore, the presence of the watercraft on the lift causes the hollow plastic tanks to bow downwardly at the ends, distorting the watercraft support frame. The use of side-of-tank tube assemblies may reduce the distortion to some extent, but the constant exposure of the metal tubes to the water far outweighs any such benefit. The deflection problem is most often resolved by the use of more plastic in the tank walls than would otherwise be necessary so as to strengthen the resistance of the tanks to deflection. Unfortunately, added plastic means a heavier and more expensive tank. In addition to these unique deficiencies, all of these known connecting systems are troublesome to install. 
   It is, therefore, an object of this invention to provide an improved watercraft lift. Another object of this invention is to provide a watercraft lift with a connecting assembly which does not use metal components below the waterline of a floatation tank. A further object of this invention is to provide a watercraft lift with a connecting assembly which does not compromise the structural integrity of the floatation tanks. Yet another object of this invention is to provide a watercraft lift with a connecting assembly which does not require the insertion of bolts through the floatation tank plastic. It is also an object of this invention to provide a watercraft lift with a connecting assembly which does not require the use of belts to girt the floatation tanks. Still another object of this invention is to provide a watercraft lift with a connecting assembly which does not require the engagement of welded tube and bracket assemblies in the side walls of the floatation tanks. An additional object of this invention is to provide a watercraft lift with a connecting assembly which does not place unnecessary stress on the floatation tank walls. Another object of this invention is to provide a watercraft lift with a connecting assembly which resists buoyancy-caused deflection of the floatation tanks. A further object of this invention is to provide a watercraft lift with a connecting assembly which enables use of thin-walled plastic floatation tanks. Yet another object of this invention is to provide a lightweight watercraft lift. And it is object of this invention to provide a watercraft lift with a connecting assembly which is easily installed. 
   SUMMARY OF THE INVENTION 
   In accordance with the invention, an improved connecting structure is provided for use in mounting a watercraft support frame on the floatation tanks of a watercraft lift. 
   A pair of pockets are spaced fore and aft in an upper longitudinal corner of the floatation tank A pair of pads have bottom surfaces sized and contoured to overlap their respective pockets and abut the top wall of the floatation tank. A pair of brackets are contoured for insertion into their respective pockets. Each bracket has a flange with a top surface contoured to abut the bottom surface of its respective pad when the bracket is disposed in its respective pocket. Upward and outward motion of each bracket relative to the floatation tank is limited by engagement of the bracket on the tank. The bracket flanges are fastened to their respective pads with the pads overlapping the pockets and abutting the floatation tank. Thus, the pads are secured in place on top of the tank without being fastened directly to the tank and the watercraft support structure can be mounted on the pads. The pockets are preferably sized for fore and aft tolerance of the brackets so as to compensate for the normal expansion and contraction of the components and forces exerted on the lifts in turbulent conditions without stressing the tank plastic. 
   In a preferred embodiment, a trough extends in the top of the floatation tank from approximately the fore to the aft pocket. The bottom of the trough slopes upwardly from the pockets to a crest. A reinforcing member extends from end to end in the trough. The pads abut the tops of the fore and aft ends of the reinforcing member and the crest abuts the bottom of the mid-portion of the reinforcing member when the pads are fastened to the brackets. This configuration of components resists buoyancy-induced bowing of the plastic tank. The reinforcing member may, for example, be a length of approximately 2″ inch square steel tubing. 
   Preferably, the top surface of the floatation tank is flat in the area of the pocket. The pocket is in the side wall of the floatation tank and opens into the flat surface on the top of the floatation tank and the pad has a flat bottom surface for juxtaposition against the flat surface on top of the floatation tank. Preferably, the bracket is engaged to the tank by use of one or more downwardly depending lugs on the side wall of the floatation tank below the pocket. In its preferred embodiment, the bracket has a lower portion contoured for engagement on the lug and an upper portion contoured for insertion into the pocket with the top surface of the bracket in the plane of the flat surface on the top of the floatation tank when the bracket lower portion is engaged on its respective lug. One or more holes through the pad open into its respective pocket and aligns with one or more holes through the bracket flange when the pad is seated on the bracket. Nuts co-operable with bolts extending through the aligned holes complete the connection. 
   In its preferred embodiment, the bracket is S-shaped with a lower portion contoured for hinging on the lug and an upper portion contoured for insertion into the pocket. The downwardly depending lug is bifurcated and respective pad and bracket holes are aligned above respective lugs. The S-shaped bracket may have a vertical reinforcing rib dividing its lower portion into fore and aft segments and contoured for disposition between the spaced-apart lugs resulting from the bifurcation. The rib may also extend to the upper portion of the S-shaped bracket. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: 
       FIG. 1  is a perspective view of a watercraft lift in accordance with the invention; 
       FIG. 2  is a side elevation view of a preferred embodiment of the floatation tanks of the lift of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view taken along the line  3 - 3  of  FIG. 2 ; 
       FIG. 4  is a cross-sectional view taken along the line  4 - 4  of  FIG. 2 ; 
       FIG. 5  is a top plan view of a preferred embodiment of the mounting pads of the lift of  FIG. 1 ; 
       FIG. 6  is side elevation view of the pad of  FIG. 5 ; 
       FIG. 7  is a front elevation view of the pad of  FIG. 5 ; 
       FIG. 8  is a perspective view of the pad of  FIG. 5 ; 
       FIG. 9  is a top plan view of a preferred embodiment of the mounting brackets of the lift of  FIG. 1 ; 
       FIG. 10  is a side elevation view of the bracket of  FIG. 9 ; 
       FIG. 11  is a rear elevation view of the bracket of  FIG. 9 ; 
       FIG. 12  is a perspective view of the bracket of  FIG. 9 ; 
       FIG. 13  is a perspective assembly view of the floatation tank, pads and brackets of  FIGS. 2 ,  5  and  9 ; 
       FIG. 14  is a perspective view of the assembled components of  FIG. 13 ; 
       FIG. 15  is a top plan view of the floatation tank of  FIG. 2  with a reinforcing member secured thereon by the pads of  FIG. 5 ; and 
       FIG. 16  is a cross-sectional view taken along the line  16 - 16  of  FIG. 15 . 
   

   While the invention will be described in connection with preferred embodiments of its components, it will be understood that it is not intended to limit the invention to those embodiments or to the details of the construction or arrangement of parts illustrated in the accompanying drawings. 
   DETAILED DESCRIPTION 
   Turning to  FIG. 1 , a watercraft support frame  10  is shown mounted on the floatation tanks  30  of a watercraft lift L. The tanks  30  are provided with pockets  50  which are spaced fore and aft and port and starboard in the upper longitudinal corners of the floatation tanks  30 . The upper longitudinal corners, as herein referenced, are the upper lengthwise corners of the tanks  30  which are formed by the junction of the tank side walls  33  and top wall  35 . 
   Pads  70 , preferably of cast iron, overlap each of the pockets  50  and abut the top walls  35  of the floatation tanks  30 . The pads  70  are seated on, but not directly connected to, the tanks  30 . Rather, the pads  70  are connected directly to plastic brackets  90 . Each of the brackets  90  has a flange  91  with a top surface  93  which is contoured to abut the bottom surface  71  of a pad  70  when the bracket  90  is disposed in a pocket  50 . The plastic bracket  90  is engaged on a lug  37  on the plastic tank  30  and rotated on the lug  37  into the pocket  50  for abutment of the flange  91  with the bottom surface  71  of the pad  70 . The bracket flange  91  is fastened to its pad  70  after the bracket  90  is engaged on the lug  37  and the pad  70  has been positioned to overlap the pocket  50  and abut the floatation tank  30 . In this position the bracket  90  cannot be rotated on its lug  37 . As a result, the pads  70  are secured in place on top of the tank  30  without being fastened directly to the tank  30  and the watercraft support frame  10  can be mounted to vertical flanges  73  on the pads. 
   The particular watercraft lift L illustrated in  FIG. 1  consists of two floatation tanks  30  with eight pads  70 . The cross members  11  and  13  secured to the pad flanges  73  form the base of the watercraft support frame  10 , the frame  10  for the purposes of this disclosure being considered to consist of the cross members  11  and  13  and all of the components of the lift supported by the cross members  11  and  13 . The actual configuration of the support frame  10  is, of course, determined by the type of watercraft to be supported. 
   As shown in  FIGS. 1 ,  5 - 8  and  13 - 14 , the pads  70  have a horizontal base  75  and a vertical flange  73 . The pads  70  are symmetrical in relation to the flange  73  and in relation to a bisecting plane perpendicular to the flange  73 . The pads  70  are preferably made of cast iron. The base  75  of the pad  70  has a flat bottom surface  71 . Holes  77  are provided through the base  75 , one in each of its four quadrants, and preferably oblong to facilitate their alignment with other lift components during assembly. A plurality of holes  79  is also provided through the vertical flange  73  to facilitate connection of the watercraft support frame  10  to the pad  70 . Additional reinforcing structure  81  may also be used to strengthen the pad  70 . 
   Looking at  FIGS. 1-4  and  13 - 16 , the tanks  30  are provided with flat surfaces  39  against which the flat-bottomed bases  75  of the pads  70  can be abutted. As seen in  FIG. 1 , in which eight pads  70  are employed, eight flat surfaces  39  are provided on the two tanks  30 . The flat surfaces  39  are located proximate the fore  41  and aft  43  and port  45  and starboard  47  portion of the top walls  35  of the tanks  30 . As best seen in  FIG. 13 , each flat surface  39  has an associated pocket  50  in the side wall  33  of the tank  30 , the pocket  50  opening through and bordered on three sides by the flat surface  39 . Each of the pockets  50  also has a downwardly depending lug  37  below it. As best seen in  FIG. 13 , the lug  37  is bifurcated, providing a gap  49  between the forward and aft portions of the lug  37 . 
   Looking at  FIG. 8 ,  9 - 14 , the bracket  90 , preferably S-shaped in cross-section as shown, has a lower portion  93  contoured to slide upwardly over and hinge on the lug  37  depending from the tank  30  below the pocket  50  and an upper portion  95  contoured for insertion into the pocket  50  as the bracket  90  is hinged on the lug  37 . The upper portion  95  of the bracket  90  has a flange  91  with a top surface  97  which is contoured to abut the bottom surface  71  of the pad  70  when the pad  70  is disposed across the pocket  50 . As the bracket  90  is rotated on the lug  37  to insert the upper portion  95  of the bracket  90  into the pocket  50 , the lower surface  99  of the horizontal midportion  101  of the bracket  90  contacts the bottom surface  51  of the pocket  50  and the lower end  103  of the S-shaped cross-section abuts the bottom  38  of the horizontal portion of the depending lug  37 , firmly seating the bracket  90  in the pocket  50 . Furthermore, as the bracket  90  rotates, the upper flat face  97  of the flange  91  reaches its maximum elevation in which the bracket flange top face  97  is in the plane of the top face  39  of the floatation tank  30  when the bracket  90  is fully inserted into the pocket  50 . 
   As best seen in  FIG. 9 , the bracket flange  91  is provided with a pair of holes  105  which are oriented to align with two of the holes  77  in the base  75  of the pad  70 . The bracket  90  is also provided with a vertical reinforcing rib  107  which, as shown, divides lower portion  93  of the bracket  90  into fore and aft segments. As best seen in  FIGS. 13 and 14 , the contour of the rib  107  is such that it can be inserted into the gap  49  in the bifurcated lug  37  with the respective pad and bracket holes  77  and  105  aligned above the forks of the lug  37 . The rib  107  may also extend as shown to divide the upper portion  95  of the S-shaped bracket  90  into fore and aft segments. When the bracket  90  has been engaged on the lug  37  and rotated into the pocket  50 , the flat bottom surface  71  of the base  75  of the pad  70  can be rested on the tank  30  in a position to overlap the pocket  50  and abut the flat upper surfaces  39  and  97  of the floatation tank  30  and the bracket flange  91 . The outboard holes  77  on the base  75  of the pad  70  can then be aligned with the holes  105  through the flange  91  of the bracket  90 . Bolts  109  inserted through the aligned holes  77  and  105  of the pad base  75  and bracket flange  91  will extend into the outwardly accessible area  111  of the bracket  90  under the flange  91  where nuts  113  can be threaded to the bolts  111  to secure the pad  70  against the flange  91  and also against the flat surface  39  of the tank  30 . Since the bracket  90  cannot be removed from the pocket  50  without rotational motion of the bracket  90  about the lug  37 , and since the bottom face  71  of the pad  70  abuts the top flat surface  39  of the tank  30  at the highest position of the bracket  90 , the bracket  90  cannot be raised or rotated and therefore cannot be disengaged from the tank  30 . This is further assured after connection of the watercraft support frame cross-members  11  and  13  to the pads  70  which, once installed on the pads  70 , prevents the pads  70  and therefore the brackets  90  connected thereto from rotating on the lugs  37 . Preferably, the fore-to-aft dimensions of the bracket  90  are less than the fore-to-aft dimensions of the pocket  50  so that some fore-to-aft motion of the bracket  90  within the pocket  50  is available to compensate for the normal expansion and contraction of the lift components and for forces exerted on the lift L during turbulent weather conditions. 
   Turning to  FIGS. 15 and 16 , a reinforcing structure  120  is illustrated. A trough  121  extends in the top wall  35  of the floatation tank  30  from approximately each fore pocket  50  to each aft pocket  50 . As shown, each tank  30  has a port side and starboard side trough  121 . The trough  121  is sloped upwardly from each of its ends  123  toward a crest  125  at a mid-portion of the length of the trough  121 . In assembling the lift L, a reinforcing member  127 , such as a steel tube of square cross-section as shown, is seated in each trough  121  before its pads  70  are mounted on the tank  30 . The reinforcing members  127  may, for example, be lengths of approximately 2″ inch square steel tubing. As best seen in  FIG. 16 , the cross-section of the tube  127  is such that, when the bottom surfaces  71  of the pads  70  are butted against the top surfaces  129  of the ends  123  of the tube  127 , the bottom surface  131  of the tube  127  is butted against the crest  125 . Thus, the reinforcing tube  121  counteracts the buoyancy-induced deflection forces on the tank  30 . The tube  127  is located at the top of the tank  30 , above the tank water line, so that the tube  127  is not constantly exposed to water. If water should collect in the trough  121 , the slopes of the trough  121  allow the water to drain towards the pockets  50 . As best seen in  FIG. 15 , the end portions  123  of the troughs  121  are redirected to enter into the inboard sides  53  of their pockets  50  rather than through the side walls  55  of the pockets  50 . Consequently, the ends  133  of the reinforcing tube  127  can be positioned in contact with opposed transverse walls  135  of the trough  121 , preventing fore and aft motion of the tube  127  in the trough  121  without extending the tube  127  into the pocket  50 . 
   The brackets  90  are engaged on, but not fastened to, the tank  30 . Therefore, the brackets  90  can be made of substantially sturdier plastic while the tanks  30  can be of relatively thin-walled plastic. Thus, the overall weight of the lift L is reduced. The cast iron pads  70  are secured by steel, but the steel is entirely above the lift water line and not immersed in water. No welding need be involved in the assembly. No mounting holes need be provided in the tank plastic. No stresses are applied to the plastic walls of the tanks  30  by components fixed directly to the tanks  30 . The use of the pads  70  facilitates the incorporation of the anti-buoyancy-deflection reinforcing structure  120 , though the reinforcing structure  120  need not necessarily be incorporated into the lift L. Furthermore, the reinforcing system  120  herein described may be incorporated into lifts which do not incorporate the tank-to-watercraft support structure herein described. 
   Thus, there has been provided, in accordance with the invention, a watercraft lift that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments of the invention and its component parts, many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.