Abstract:
A swim lift platform using hydraulic force to lift a swimmer between positions in which the platform is above water level to a submerged position. The movement is under the control of a swimmer occupying the platform.

Description:
REFERENCE TO RELATED APPLICATION 
   This application claims priority from U.S. Provisional Patent Application Ser. No. 60/403,038 filed Aug. 13, 2002, the content of which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   This invention relates to swim platforms for boats and more particularly to a swim platform which can be adjusted in elevation by the use of hydraulic power. 
   BACKGROUND OF THE INVENTION 
   Swim platforms have been mounted on the transoms of boats but usually such platforms are supported in a fixed position or can be folded to a transport position. Typically, ladders are attached to permit a user to enter the water and to return from the water to the platform. 
   There is a need for a swim platform to facilitate movement from the boat to the water and from the water back to the boat without the need for physical exertion required by ladders. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to provide a swim platform which can be supported from the stern transom of a boat in a position to move vertically downwardly and to return to its initial position under the control of the person using the swim platform. 
   It is a further object of the invention to provide a vertically adjustable and moveable swim platform which affords a method of moving from the boat to the water and from the water back into the boat using a minimum amount of strength and energy. 
   The objects of the invention are attained by an arrangement which includes a pair of parallel spaced apart guide members mounted in a stationary position vertically at the transom of the boat and having a lift platform attached at its opposite sides to guided members complementary to the guide members for sliding vertical movement relative to each other. A single hydraulic actuator is supported between the guide and guided members and has its cylinder end fixed relative to the transom of the boat and its rod end acting on the lift platform. The hydraulic cylinder is a two-way cylinder and has a connection to an electrically powered hydraulic pump and hydraulic system. The pump is under the control of an electric switch mounted or stored in a readily available access position and moveable with movement of the swim platform. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of one embodiment of the swim lift platform embodying the invention mounted on the transom of a boat looking from the aft, starboard side of the boat and shown in its lowered position; 
       FIG. 2  is a side view taken generally on line  2 — 2  in  FIG. 1  showing the lift platform in its upper or transport position; 
       FIG. 3  is a perspective view of another embodiment of the invention similar to  FIG. 1 ; 
       FIG. 4  is a side view taken in the direction of line  4 — 4  in  FIG. 3  showing the lift platform in its upper transport position; and 
       FIG. 5  is a top view of the structure seen in  FIG. 4  but at an enlarged scale. 
   

   DETAILED DESCRIPTION 
   The swim lift platform embodying the present invention is designated generally at  10  and includes a pair of parallel spaced telescoping guide members  12  which are supported in a stationary position relative to the transom  13  of a boat. The lower ends of the guide members  12  support a platform  14  which is moved vertically relative to the transom of the boat by a double acting hydraulic actuator  16 . 
   The guide members  12  are held in parallel spaced apart relationship by an upper and lower support member  18  and  20 , respectively, which acts to hold the guide members in fixed relationship relative to each other. The upper ends of the guide members  12  are further supported in spaced relation from the transom of the boat by a pair of upper brackets  22  and the lower ends by a pair of lower brackets  24 . The brackets  22  and  24  may be made of various sizes to accommodate variations in the angle of the transoms of boats on which the swim lift platform  10  is mounted. Typically the guide members  12  may be made of stainless steel tubing and each includes an outer tube  26 , and a telescoping inner tube  28 . The lower ends of the inner tubes  28  are attached to the horizontal platform  14 . The platform  14  is provided with a forward wall or guard member  32  and a pair of side guard members  34  that serve to protect the feet of a user standing on the platform  14 . The members  32  and  34  as well as the platform  14  are made of metal such as stainless steel and preferably are perforated or in the form of a grille to permit water flow and at the same time offer a non-skid surface as well as be comfortable upon contact by the feet of a user. 
   A pair of handle bars  40  are disposed to opposite sides of the platform  14  and extend from the platform  14  upwardly to support collars  42  that slide on the exterior outer tube  26  of the guide members  12  during vertical up and down movement of the platform  14  between the lowered position seen in  FIG. 1  and the upper transport position seen in full line in  FIG. 2 . The platform  14 , the inner guide tubes  28  and handlebars  40  all move as a unit and are regarded as forming a platform assembly or carriage. 
   A hydraulic actuator  16  having a hydraulic cylinder  52  and extendable piston rod  54  is disposed between the guide members  12  and rearwardly of the support members  18  and  20 . The hydraulic cylinder  52  is mounted in a fixed position relative to the boat transom  13  and more particularly to the upper support member  18  and lower support member  20 . The rod end  54  is attached to the swim platform  14 . The hydraulic actuator  16  is connected hydraulically to a pump system indicated at  56  that is driven by an electric direct current motor  58 . The motor  58  and the hydraulic pump system  56  are under the control of an electrical control switch  62  which is detachably supported by one of the handlebars  40  for easy reach by the user and is connected electrically by a flexible connector  63  seen in  FIG. 1 . Actuation of the switch  62  determines the direction and amount of movement of the hydraulic actuator  16 . 
   In its storage position with the hydraulic actuator  16  in its collapsed condition the platform is at the lower end of the boat transom and near the water level as seen in  FIG. 2 . The user can leave the cockpit of the boat to stand on the platform  14 . Subsequent operation of the switch  62  causes operation of the hydraulic actuator so that the rod  54  extends from the cylinder  52  causing the platform  14  to be lowered together with the handle bars  40 , the upper ends of which slide on the guide members  12 . At the lower end of travel on the platform  12 , as seen in  FIG. 1 , the user is partially immersed in water and can leave the platform. 
   To return from the water to the boat, the user steps on the platform  14  and actuates the switch  62  in an upward direction so that the rod  54  retracts into the hydraulic cylinder  52  lifting the platform  14  to its original position where the user may leave the platform and re-enter the boat. 
   Another embodiment of the invention is shown in  FIGS. 3 through 5  in which the swim lift platform  10  has a foot supporting platform  64  with a forward wall or guard  66  and an opposed pair of side walls or guards  68  which are formed integrally with each other to form a platform carriage assembly indicated at  70  in  FIG. 3 . In this case, guard walls  66  and  68  extend the full height of the carriage  70 . 
   The platform carriage  70  is supported vertically on the transom  13  of a boat by a pan-like mounting structure  71  having a support wall  72  and a pair of opposed side walls  74  each having flange portions extending outwardly from each other to form stationary guide members  76 . Support wall  72  of the mounting structure  71  is intended to be supported vertically relative to the transom  13  of a boat. In the case of a vertical transom the support wall  72  can be fastened in abutting relation directly to the transom of the boat. If the transom is not vertical, brackets or spacers (not shown) can be used to position the mounting structure  71  vertically. 
   The platform carriage  70  is provided with a pair of bracket portions  78  extending rearwardly of the guard wall  66  as seen in  FIG. 5  to form a guide track to slidably receive the pair of stationary guide members  76  so that the platform carriage assembly  70  can have guided sliding movement. The top edge of forward wall  66  is provided with a shield in the form of a horizontal shelf  81  which closes the upper end of the space formed by the mounting structure  71  but allows space for the hydraulic actuator  16 . 
   Movement of the platform carriage assembly  70  is achieved with the same hydraulic actuator  16  used in the embodiment shown in  FIGS. 1 and 2 . The hydraulic actuator  16  has a cylinder  52  and extendable rod portion  54  supported in the space afforded between the back of the guard wall  66  and the support wall  72  of the mounting structure  71 . The hydraulic actuator  16  is held centrally between the opposite sidewalls  74  of the mounting structure  71  by an upper pair of brackets  82  at opposite sides of the cylinder  52 . Similarly, the lower end of the cylinder is held by a bracket  84 . 
   The end of the hydraulic actuator rod  54  is connected to carriage lift member  86  which extends radially from the rod  54  to engage the bottom of the platform  64  of the carriage assembly  70 . The hydraulic actuator  16  of the structure seen in  FIGS. 3 ,  4  and  5  is connected to the hydraulic pump system in the same manner as the hydraulic actuator  16  seen in  FIG. 1 . The electric control switch  62  seen in  FIG. 1  is connected electrically by a flexible conductor  63  and in the embodiment of the invention seen in  FIG. 3 , the control switch  62  can be held in a bracket  90  indicated at the upper portion of the platform carriage  70 . The switch  62  can be removed from the bracket to other positions of operation as determined by the length of the conductor  63 . 
   The operation of the embodiment seen in  FIGS. 3 through 5  is generally the same as the operation of the embodiment disclosed in  FIGS. 1 and 2 . 
   All of the components of the platform carriage  70 , the mounting structure  71  and the hydraulic actuator preferably are made of stainless steel. 
   Operation by the operator standing on the platform  64  is accomplished by using the switch  62  which has “up” and “down” marked portions. Actuation of switch  62  can be initiated by pressing the “down” switch and holding it engaged until the desired elevation of the platform  64  is attained. Releasing the switch will stop movement of the platform. When the desired level is reached, the user can leave the platform and it will be in position for return travel. 
   During use of the swim lift platform, hand holds  92  formed in the sidewalls  74  can be used for support. Also, the forward wall can be provided with steps indicated at  96  to assist during boarding and leaving of the platform  64  of the carriage assembly  70 . 
   A modification of the embodiment seen in  FIGS. 3 through 5  can be achieved by substituting handrails  40  such as seen in  FIG. 1  for the sidewalls  74  seen in  FIG. 3 . In that case the upper part of the handrail  40  can be joined directly to the top of the forward wall  66  in  FIG. 3  instead of to the collars  42  seen in  FIG. 1 . 
   A swim platform for boats has been provided which can use power such as a hydraulic cylinder to lower a user into the water and to raise the user from the water without the need for ladders and without the physical effort required using ladders.