Abstract:
A boat hoist comprising a column, a tubular hoist slidable vertically, on said column, a boat cradle on said hoist, shore reinforcement means to anchor an upper part of said column to the shore, and a power unit connecting said column and hoist.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a boat hoist. 
     The boat hoist is intended to be installed at water&#39;s edge, adjacent to a seawall if one is available, or a dock or the like. 
     In the past conventional boat hoists required unsightly overhead steel constructions, and usually a multiplicity of cables, sheaves, etc., all of which is avoided with the present construction. 
     The boat hoist of the present invention comprises essentially a vertical column which may be driven as a pile into the water bed where the hoist is dockside, or adjacent a seawall. Alternatively, it may be secured directly to a seawall, pier, dock, or the like. 
     The hoist is an elongated tubular member slidable over the column, and slotted to accommodate a connection between the column and a shore based anchor or support. The hoist is raised or lowered by a power unit connected between the column and hoist. Preferably the column is tubular, and the power unit is a piston and cylinder unit located with the column. 
     DEFINITION OF TERMS 
     Herein the term seaward means a direction away from the land and toward the water, or the boat cradle. 
     The term shoreward means the direction opposite to seaward. 
     The term water bed means the soil or ground beneath the water, into which the post of the hoist construction may be driven. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic elevational view with the hoist in lower position. 
     FIG. 2 is a view similar to FIG. 1 with the hoist in raised position. 
     FIG. 3 is a diagrammatic plan view of the structure shown in FIGS. 1 and 2. 
     FIG. 4 is a fragmentary view showing the lower end of the support column driven into the bed of the water. 
     FIG. 5 is an elevational view of the hoist with parts broken away. 
     FIGS. 6-8 are sectional views on the lines 6--6, 7--7 and 8--8 respectively, in FIG. 5. 
     FIG. 9 is a diagrammatic plan view illustrating a different embodiment of the invention. 
     FIG. 10 is a sectional view illustrating a different mounting for the bottom roller means. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, the boat hoist is intended for erection at dockside, or adjacent a seawall 10, the water level being indicated at 12 and the bed of the water being seen at 14. 
     The hoist construction as illustrated in FIGS. 1-3 comprises a rigid post 16 adapted to be fixed to a seawall 10 and attached to a land anchor 20 by suitable tension connections indicated at 22. The land anchor may comprise a massive concrete construction buried in the soil and reinforced by metal bars or beams as indicated at 24. 
     The anchor connection 22 is adjacent the top of the post in position to resist forces tending to move the top of the post outwardly away from the shoreward side. As seen in these figures the lower end of the post may be provided with a pad 26 welded or otherwise fixed to the seawall. 
     In FIG. 4 there is illustrated an alternative construction, in which the lower end of the post is driven as by a pile-driver into the water bed 14 to a depth sufficient to sustain the weight of a boat to be hoisted from the water. 
     In either case, vertically movable on the post 16 is a tubular hoist 30 having a boat cradle 32 of suitable design. If desired, the hoist apparatus may comprise a pair of posts, hoists and cradles in juxtaposition and suitably coordinated for simultaneous operation to engage forward and aft portions of a boat 34. 
     Referring now to FIGS. 5-8, details of the hoist construction are shown. 
     The post 16 in this Figure is shown as provided at its lower end with pad 26 for attachment to a seawall or the like, but of course as indicated in FIG. 4, it may be pile driven into the bed or bottom below the surface of the water. The bottom end of the post 16 is closed as indicated at 36. In a practical design of this construction pipe 16 may be of 6&#34; diameter. 
     Telescoped over the post 16 is a tubular hoist which in the above mentioned design is an 8&#34; diameter pipe having an upper end closure 40 welded to hoist pipe 30. The weld connection is sufficiently strong to sustain a lifting force required to hoist a boat to a storage position above the water. 
     Since the shore connection 22 is located near the upper end of post 16 the hoist 30 must be slotted from its lower end to a height sufficient to receive connection 22 when the hoist is in lowered position. In the practical design referred to, provision is made for 8&#39; travel of the hoist. The connection 22 is a flat steel plate welded along one edge to the post. 
     The slot in the tubular hoist is seen at 45. In order to reinforce the slotted portion of the hoist flanges 47 are welded to the outside of the tubular hoist at the sides of the slot and are bolted together as indicated at 48. Bolt 48 are so located that when the tubular hoist is in uppermost position, it is below the anchor connection 22. 
     Within the post 16 is a hydraulic cylinder 41 which preferably rests on bottom closure plate 36 and the cylinder 41 contains a piston rod 42, the upper end of which engages beneath plate 40, and serves to lift the hoist when hydraulic fluid is admitted to the cylinder 41, as by hydraulic line 44 connected to the cylinder below the position occupied by piston 42 when the hoist is in lowered position, by a suitable internal connection, not shown. 
     Preferably flanges 47 are also provided with openings so adapted to receive a pin which extends through an opening 52 in the plate 22 forming part of the anchor connection, so that the tubular hoist may be mechanically locked in raised position, and pressure within the cylinder 41 released. 
     It will be apparent that when a heavy boat is hoisted, forces are developed tending to swing the upper end of the tubular hoist outwardly toward the boat cradle side, and at the same time forces are developed tending to swing the lower end of the hoist inwardly away from the boat cradle side. In order to sustain these forces, and at the same time to provide for vertical movement of the tubular hoist with minimum friction, roller bearings are provided. 
     At the top of the post 16, the plate 37 carries the pairs of brackets 54, and each pair receives a shaft 56 which supports a roller bearing 58. The two roller bearings, as best seen in FIG. 6, are spaced circumferentially to engage the inner surface of tubular hoist 30 at opposite sides of and closely adjacent to the slot 45, when the hoist is raised to a position in which the slot is at the top of post 16. 
     At the lower end of the tubular hoist, roller bearing means is provided which are engageable with the seaward side of the post 16. As indicated in FIG. 5, the roller means 60 may be supported by brackets 62 welded to a strut 64 of the cradle structure 32. Preferably, a pair of rollers 60 are provided at opposite sides of bracket 62, to divide the loading and to ensure stability. 
     Alternatively, as seen in FIG. 9, instead of the rollers 58 carried at the top of post 16 and engageable with the interior of the tubular hoist 30, a roller 70 supported for rotation on brackets 72 may engage directly against the exterior of tubular hoist 30. The brackets 72 may be fixed to a seawall 10 or suitably rigidly connected to the land-based anchor 20 as for example by being secured to said tension connection. In this case, of course, the connection 22 to the post 16 may be omitted. 
     In FIG. 10 there is illustrated a different mounting means. Here bracket plates 80 are welded to the tubular hoist adjacent its bottom end, and the hoist is cut away as indicated at 52 to permit a roller mounted between plates 80 to engage the seaward side of the stationary post. 
     In the event that a single post and tubular hoist is used, the cradle may be elongated in the direction of the length of the boat, and the top of the post may be provided with a pair of shore anchors to provide full stability for the post. 
     From the foregoing, it will be apparent that the boat hoist is characterized particularly by one or more stationary vertical posts, each of which has a tubular hoist which receives the post and which is vertically slidable thereon. The boat cradle which lifts the boat is a cantilever construction extending laterally from the hoist.