Watercraft lift system

Abstract

A watercraft lifting system includes a bunk rail assembly, an intermediate frame assembly, a base assembly and a ground support assembly. The bunk rail assembly includes a bunk rail coupled to a load distribution member. The load distribution member is received by the bunk rail such that the bunk rail may rotate by at least a limited amount relative to the load distribution member. The bunk rail may slideably receive a bunk cushion and form a channel therewith for sandwiching a rigid structural member (e.g., a board). The watercraft lifting system may also include contoured clamps that cooperate to distribute and transfer load between frame members. In one embodiment, the contoured clamps include parabolically-shaped inner surfaces.

1 . A bunk rail assembly for a watercraft lifting system, the assembly comprising:
 a rail having a length sufficient to support a desired type of watercraft; and   a load distribution member having a bearing surface shaped to be closely received by a correspondingly shaped surface of the rail, wherein the respective surfaces permit rotation of the rail relative to the load distribution member, wherein the load distribution member is coupled to the rail with a fastener assembly arranged in a through slot formed in a wall of the load distribution member.   
   
   
       2 . The bunk rail assembly of  claim 1  wherein the load distribution member is rotationally connected to an intermediate frame assembly of the watercraft lifting system. 
   
   
       3 . The bunk rail assembly of  claim 1  wherein the respective surfaces permit rotation of the rail relative to the load distribution member. 
   
   
       4 . The bunk rail assembly of  claim 1  wherein the load distribution member is coupled to the rail with a fastener assembly arranged in a through slot formed in a wall of the load distribution member. 
   
   
       5 . The bunk rail assembly of  claim 4  wherein the fastener assembly cooperates with the edges of the slot to limit the relative rotation between the rail and load distribution member. 
   
   
       6 . The bunk rail assembly of  claim 1  further comprising a fastener assembly for coupling the rail to the load distribution member. 
   
   
       7 . The bunk rail assembly of  claim 1  further comprising a bunk cushion having a cross section configured to be slideably coupled to the rail. 
   
   
       8 . The bunk rail assembly of  claim 7  further comprising an elongated board received in a channel formed by the rail and the bunk cushion, wherein the fastener assembly couples the load distribution member the board. 
   
   
       9 . The bunk rail assembly of  claim 7  wherein the rail includes side flanges for receiving and supporting the bunk cushion. 
   
   
       10 . A watercraft lifting system comprising:
 a base frame assembly;   an intermediate frame assembly pivotally coupled to the base frame assembly; and   a bunk rail assembly pivotally coupled to the intermediate frame assembly, the bunk rail assembly having a rail engaged with a load distribution member that is pin-connected to the intermediate frame assembly, the load distribution member having a periphery surface shaped to be closely received within a correspondingly shaped inner surface of the rail.   
   
   
       11 . The watercraft lifting system of  claim 10  wherein the respective surfaces permit rotation of the rail relative to the load distribution member. 
   
   
       12 . The watercraft lifting system of  claim 10  wherein the load distribution member attaches to the rail with a fastener assembly extending through an elongated slot formed in a wall of the load distribution member. 
   
   
       13 . The watercraft lifting system of  claim 12  wherein the fastener assembly includes a threaded member for engaging the rail and a bushing receivable in the slot. 
   
   
       14 . The watercraft lifting system of  claim 10  wherein the bunk rail assembly includes a bunk cushion having a cross section configured to be slideably received by the rail. 
   
   
       15 . The watercraft lifting system of  claim 10  wherein the bunk rail assembly includes an elastomeric bunk cushion slideably received by the rail. 
   
   
       16 . The watercraft lifting system of  claim 10  wherein the bunk rail assembly includes a board slideably received within a channel formed by a bunk rail cushion attached to the rail. 
   
   
       17 . The watercraft lifting system of  claim 10  wherein an elongated slot formed in the load distribution member limits the rotation of the rail relative to the load distribution member. 
   
   
       18 . A clamping assembly for a watercraft lifting system, the clamping assembly comprising:
 a load transferring member;   a load receiving member having an outer tapered surface; and   a clamping member having opposing flanges extending from a base portion, an outer surface of at least one opposing flange attachable to the load transferring member;
 an inner surface defined by the flanges and base portion being complementarily tapered to closely nest with the outer tapered surface of the load receiving member. 
   
   
   
       19 . The clamping assembly of  claim 18  further comprising a tensioning assembly arranged to urge the opposing flanges toward one another and correspondingly provide a contact pressure between the tapered surfaces. 
   
   
       20 . The clamping assembly of  claim 18  wherein the tensioning assembly includes a threaded fastener that extends through both flanges. 
   
   
       21 . The clamping assembly of  claim 18  wherein the outer tapered surface of the load receiving member includes a parabolically-shaped surface. 
   
   
       22 . The clamping assembly of  claim 18  wherein a length of the clamping member cooperates with the load receiving member to distribute load from the load transfer member over approximately the length of the clamping member. 
   
   
       23 . The clamping assembly of  claim 18  wherein the at least one opposing flange being attachable to the load transferring member includes the load transferring member pivotally coupled to the flange. 
   
   
       24 . The clamping assembly of  claim 18  wherein the outer surfaces are planar surfaces. 
   
   
       25 . The clamping assembly of  claim 18  wherein the tapered surfaces closely nesting together includes a frictional engagement between the surfaces sufficient to structurally lock the clamping member onto the load receiving member.