US3114535A - Boat lifts - Google Patents

Description

L. P. BURCH BOAT LIFTS 3 Sheets-Sheet 1 Filed April 11, 1961 p I n I p n I Tr m 7 WW M y n B5 M B 7 Mm a A M ZMN@ Dec. 17, 1963 L. P. BURCH 3,114,535

, BOAT LIFTS Filed April 11, 1961 5 Sheets-Sheet 2 8 Kim-52:: 4 I: \/0

BY Mia-M Dec. 17, 1963 P. BURCH 3,1

' BOAT LIFTS Filed April 11, 1961 3 Sheets-Sheet 3 United States Patent ()fiice artists Patented Dec. 17, 1%63 3,114,535 BOAT LIFTS Loren F. Burch, deceased, late of Aberdeen, Wash, by

Henry Ellis Burch, executor, Aberdeen, Wasl1., amignor to Bnrcherait Boat (30., line, Aberdeen, Wash, a corporation of Washington Filed Apr. 11, 1961, Ser. No. 102,322 2 (Ilaiins. (Cl. 254-127) This invention relates to a boat lift for engaging the bottom of a boat lying in a boat slip to raise it from the water.

A principal object of lifting the boat from beneath is to eliminate the need for slings embracing the boat or lifting rings or other fittings of special character to which overhead hoisting mechanism would be attached. Also virtually the entire sides of the hull and top of the boat are unobstructed and completely accessible.

Another object is to provide such a boat lift which, without adjustment, will accommodate boats varying considerably in size.

It is also an object to provide such a boat lift which is equipped with automatic chocking mechanism acting to maintain the boat substantially on an even keel after it is raised from the water, or While it is being raised. Alternatively the boat can be steadied by other types of props associated with the lift.

In such a boat lift it is an object to provide mechanism which can produce the necessary lifting force by the use of mechanism having great mechanical advantage, so that a comparatively small effort will be required to operate the lift.

As another object the lift structure serves the double function of providing a strong support for the boat and affording an effective location for application of the lifting force.

The foregoing objects can be accomplished by a boat lift composed of a plurality of articulated cradle beams disposed in parallel relationship. Such beams are supported at their ends and can have their central portions depressed in a boat slip to enable a boat to be floated over such beams. The beams can then be straightened to raise their central portions and lift the boat out of the water by drawing together arms projecting downward from the central portions of the beams alongside hinge joints connecting opposite end portions of the beams. Prop devices for holding the boat on an even keel as it is thus raised out of the water can be either chocks carried by the beams and raised automatically as they are straightened, or steadying poles mounted on the beams extending upward alongside the boat and engaged with the sides of the boat.

FIGURE 1 is a top perspective of a preferred form of boat lift in raised position and FIGURE 2 is an elevation of such boat lift in the same position. FIGURE 3 is an elevation of such boat lift in depressed position.

FEGURE 4 is an elevation of the lower portion of the boat lift with parts broken away and FIGURE 5 is a horizontal sectional view taken on line 5-5 of PEG- URE 4-.

FIGURE 6 is an elevation of a somewhat modified boat lift in depressed position. FIGURE 7 is a similar view with the boat lift in partially raised position and FIGURE 8 is a similar view with the boat lift in fully raised position.

FEGURE 9 is an elevation of another form of boat lift in depressed position.

FIGURE 10 is an elevation of still a different form of boat lift in depressed position.

The boat lift of the present invention is particularly useful for lifting boats relative to a floating dock without the necessity of providing superstructure suiflciently high to afford ample clearance for a boat and hoist beneath it, and sufficiently strong to support the weight of a boat when it has been lifted out of the water. Such superstructure not only itself is expensive to construct, but would add greatly to the weight of the floating structure so that the float would be much more expensive to build than is necessary to accommodate a boat lift according to the present invention. =It is a principal characteristic of the present boat lift, therefore, that it is supported directly from the deck 1 of a floating dock 2 at opposite sides of the slip 3 provided to accommodate a boat between the two parts of a floating dock.

The boat lift structure is an articulated cradle composed of a plurality of parallel articulated beams spanning the boat slip 3 and having their opposite ends bearing on the decks 1 of the spaced float units 2. Each beam includes opposite end sections 4 disposed generally in lengthwise alignment, adjacent ends of which are secured together by a hinge joint 5. Each of these beam sections is generally straight but the upper surfaces 6 of their adjacent portions may be somewhat concave, as shown in FIGURES 1, 2 and 3, to afford greater clearance for the hull of a boat B above the beams when they are in their depressed positions of FIGURE 3. The beams preferably are interconnected by a keel rest channel 7 which may be mounted directly on the pivots of the hinges S, or can rest on the hinge connected portions of the beams. For most purposes a boat lift having only two articulated beams will be suflicient, although a great or number of beams may be provided to support the keel rest channel if their movement between depressed and raised positions is coordinated.

To lift a boat well out of the water, the boat lift must be movable from a depressed position such as shown in FIGURE 3 to a raised position such as shown in FlG- URE 2. In both positions the opposite or extreme ends of each beam formed by the beam sections 4 are supported from the decks 1 by supports movable to vary the spring between them. To provide clearance for the beams when they are inclined downward from their extreme ends, as shown in FIGURE 3, the upper corners of the floats 2 have notches 8 in them of a width to receive the beams, as shown in FIGURE 3. Each end of the beam has a bearing rod 9 extending transversely of the beam secured to it to provide the same type of hearing support for the beam ends in all tilted positions of the beam sections. Preferably these bearing rods rest on slides til shown best in FIGURE 1 located beneath opposite ends of the bearing rods. The bearing rods move along these slides between the positions of FIG- URES 2 and 3 as the efiective length of the beams is varied by the change in angular relationship of the beam sections.

Projections 11 extend downward in adjacent relationship from the adjacent ends of the beam sections 4. Preferably these projections taper downward and serve the duel purpose of reinforcing the central portion of the articulated beam and of affording locations for application of forces to eifect relative swinging of the beam sections 4 to raise the beam from its depressed position shown in FIGURE 3 to its elevated position of FIGURE 2. In order to provide the greatest leverage relative to the axis of the hinge 5, the force should be applied to each projection 11 as far from the hinge axis as possible. By tapering the projections away from the beam, the junction between the projection and the beam section is made sufficientiy strong to withstand the leverage produced on the extension by the application of the force to the end of the extension. Such extensions also stiffen the central portion of the beam to resist bending in the beam.

To swing the beam sections 4 relative to each other about the axis of binge 5 from the depressed position of FIGURE 3 to the raised position of FIGURE 2 it is necessray to draw toward each other the ends of projections 11. The pulling force required for this purpose can be applied to the projections by tackle interconnecting them. Such tackle may include pulleys 12 mounted on the projections by axles 13. Such projections can be hollow or formed by parallel spaced plates disposed parallel to the lift beam between which the pulleys are received and in which the ends of axles 13 can be mounted. The tackle line looped around such pulleys includes a standing stretch 14, the end of which is secured by an anchor 15 to one of the projections 11. The hauling stretch 16 of the line engages a pulley 17 mounted on the projection 11 opposite that to which the standing stretch 14 of the line is secured. Such hauling stretch extends to a winch 18 mounted on a pedestal 19 on the end of the beam section on which the guide pulley 17 is mounted.

As the handle of winch 13 in turned to reel in the hauling stretch 16 of the tackle line, the pulleys I12 will be drawn from the relative positions shown in FIGURE 3 toward each other so as to effect relative swinging of the beam sections 4 about the axis of hinge 5 toward alignment to raise the central portion of the beam toward the position of FIGURE 2. Such relative movement of the beam sections will move their extreme ends apart so that the bearing rods 9 slide away from each other along the slides it). If the keel of the boat B has been located over the keel rest channel '7, the boat will be raised out of the water as the beams supporting such channel are straightened. The weight of the boat is gradually transferred from the water to the lift and consequently the effort required to turn the winch will increase gradually. As each beam is raised the leverage of the projections 11 is improved to some extent. If greater mechanical advantage is required to lift the Weight of the boat easily, additional pulleys can be included in the tackle or reduction gearing can be provided in the winch, or both.

As the boat is raised out of the water it normally would tip in one direction or the other so that it would be supported jointly by the keel rest 7 and additionally by the port or starboard sections 4 of the lift beams. To equalize the load on the lift beams and to prevent tilting of the boat, props carried by the lift beams can be provided. These props can be arranged to be moved into boat-engaging position automatically by relative movement of the lift beam sections 4. In FIGURES 1 to 5, inclusive, chock rods 20 are shown supported alongside the beam sections 4 having heads 21 engageable with the bottom of the boat, which heads can be padded or made of soft material to avoid injuring the boat hull. Chocks of this type are most suitable for V-bottom boats and it will be understood that suitable provision can be made for adjusting the height of such chocks, or selecting chock rods of a length suited to the size and shape of the boat being lifted.

Such chock rods are mounted on elevating mechanism so that they will be moved upward either progressively as the boat is raised, or rapidly near the end of the lifting movement so that they will engage the bottom of the boat when it has been raised to its uppermost position. During the lifting movement the boat can be steadied manually in its upright position. The lower ends of these rods are mounted by pivots 22 on the swinging ends of levers 23, the central portions of which are carried by fulcrum pivots 24 on the beam sections. The chock rods are held in upright positions by passing through guide loops 25 mounted on the beam sections above the pivots 22. The chock rods are raised into boat-engaging position by swinging levers 23 to raise the pivots 22.

To swing the levers 23 about their fulcrums 24 for sliding the chock rods 20 upward, an arrangement is provided for exerting pressure on the ends of the levers remote from the chock rods as the articulated beams are straightened to lift the boat. A pressure bar 26 is carried by each beam section 4 inclined downwardly from the hinge end and toward the downward projection ill. Such bars may conveniently be mounted on the hinge pivot and the axles 1 .3, but since each pressure bar is fixed relative to its beam section, it can be fixedly mounted to such beam section in any convenient manner. The pressure bar mounted on one beam section engages the adjacent end of the lever 23 on the other section of the beam, as shown in FIGURES 2, 4 and 5. The lever ends may be turned as shown best in FIGURES l and 5 to facilitate such engagement.

It will be evident from FIGURE 3 that the heads 21 of the chock rods engage the beam sections or the guide loops 25 to limit downward movement of the chock rods. With the rods in their lowest positions, the pressure bars 26 will engage the bent ends of the levers 23 at an angle such as to cause the lever arms to slide down the pressure rods as the projections 11 are drawn together. Such pressure on the lever ends effects lengthwise upward projection of the chock rods 20 so that such chock rods will be in boat-engaging position when the projections have moved toward each other to the positions shown in FIGURES 1, 2 and 4. The chock rods will be maintained in such raised positions as long as the cradle beam is in its raised position, but as the beam is lowered from its position of FIGURE 2 toward its position of FIGURE 3, the pressure of the pressure bars 26 on the lever ends will be relieved by separating movement of the projections 11 and the chock rods 26 will slide downward again into their retracted positions of FIGURE 3.

In FIGURES 6, 7 and 8 the type of cradle beam lift is quite similar to that shown in FIGURES 1 to 5, inclusive, but in this instance the upper sides of the beam sections 4- are straight instead of the outboard end portions having concave upper surfaces. Moreover, the floats 2 do not have notches in their corners to accommodate the beam sections, but the slides 16' are elevated somewhat above the decks 1 of the float to afford clearance for movement of the beam sections. Also, the projections 11 are formed as triangular trusses instead of being of plate material. The tackle connecting pulleys 12 and including the hauling stretch 16, however, can be the same as in the boat lift described above and such hauling line stretch is secured to a winch 18 mounted on a pedestal 19 which is carried by a beam section 4. The extreme ends of the beam sections can be carried by rollers 9 engaging the slides or tracks 10 instead of simply a bearing rod if preferred. The adjacent ends of the lift beam sections are connected together by a hinge 5, as described previously. The cradle beams are connected together at the location of their hinges by a keel rest member 7.

It is assumed that the boat lift shown in FIGURES 6, 7 and 8 will be used to lift boats larger than those for which the lift shown in FIGURES 1 to 5, inclusive, would be used. Consequently, two winches 18 are shown on each cradle beam and they will be connected to separate tackle systems interconnecting the projections ll. Two men would therefore operate the two winches on each cradle beam simultaneously but it is not necessary for both cradle beams to be raised simultaneously. Instead, such cradle beams could be raised alternately, first one through an increment and then the other, until both beams have been raised to their uppermost positions. In general, the boat lifting operation of the boat lift shown in FIGURES 6, 7 and 8 will be the same as described in connection with FIGURES 1 to 4, inclusive.

The boat B shown in outline in FIGURES 6, 7 and 8 is of the round bottom type. It is more difficult to provide hull-engaging chocks for such a boat which would be projected automatically into hull-engaging position as the boat is raised. The boat lift shown in these figures, therefore, is provided with steadying poles, or bars, 27 located on each side of the boat, instead of chock devices. The lower ends of these poles are connected to the respective cradle beam sections at opposite sides of the boat and the upper ends of such poles are moved appropriately from time to time so that the poles will engage the boat hull. The sides of such poles adjacent to the boat may be padded to prevent the boat hull from being marred or injured by the steadying poles.

Movement of the upper ends of the poles 27 can be controlled from a location remote from the poles. Satisfactory handling mechanism for this purpose includes pulleys 28 carried by the upper ends of the poles and guide pulleys 29 suitably supported for guiding a line 30. One end of such line is secured by an anchor 31 to a float 2 and the other end of the line can be secured at will to a cleat 32. The linepasses from the anchor 31 around guide pulleys to a pulley 28 on a steadying pole 27, then across :to the other steady-ing pole and around further guide pulleys 29 to a location adjacent to the cleat 32.

When the cradle beam is deprmsed and the boat B is floating in the water, as shown in FIGURE 6, the spacing between the locations at which the poles 27 are connected to the beam sections 4 will be less than the width of the boat B. As the beam sections are swung relatively toward alignment, the points at which the poles 27 are connected to the beam sections will move farther apart, as indicated in FIGURE 7. In order to maintain the steadying poles in engagement with the sides of the boat hull, therefore, it is necessary to shorten line 30 for the purpose of drawing the upper ends of the poles toward each other. When the line has been thus shortened it can be fastened again to cleat 32. As the boat is raised further, the points on beam sections 4' to which the poles are connected will move apart somewhat farther, as shown in FIGURE 8, and again it will be desirable to shorten the line 30 and secure the line in such shortened condition to cleat 32 again. With the boat thus fully raised the poles "will prevent it from tipping appreciably.

In FIGURE 9 a boat lift is shown including articulated cradle beams, projections and lifting tackle similar to that previously described, so that it is unnecessary to repeat the description in detail. In this instance, however, the inboard ends of the beam sections 4" are suspended by links 33 from suitable superstructure mounted on the floats 2. When the adjacent ends of the beam sections are depressed to the full line positions shown in FIGURE 9, the extreme ends will be drawn toward each other to swing the lower ends of links 33 into the solid line positions shown. As the winch and tackle raises the adjacent ends of the beam sections 4", the extreme ends of such sections will be moved apart until they reach the broken line positions shown in FIGURE 9. Such beam movement will have swung the links 33 to their broken line positions shown.

In FIGURE 10 the boat lift mechanism again is similar to that previously described. In this instance, however, instead of the extreme ends of the beams sections 4" being carried by the lower ends of suspension links, as described in connection with FIGURE 9, such beam section ends are mounted on the upper ends of strut links 35, the lower ends of which are mounted on the floats 2 by anchor pivots 36. When the cradle beam is in the depressed position the upper ends of links 35 will be swung toward each other, as shown in full lines in FIGURE 10, but as the beam is raised by manipulation of the winch and tackle mechanism to the broken line position shown in this figure, the separating movement of the extreme ends of the beam sections will swing such strut links oppositely into the broken line positions shown in FIGURE 10.

The boat lift of the present invention may be used in salt water, in which case the portions of the mechanism which will be submerged when the lift is in use should be made of noncorrodible or corrosion resistant material as far as possible. The beam sections and projections can be made of wood, the pulleys should be made of plastic or brass and the lines can be made of stainless steel cable, or of rope. When the lift is not in use it is desirable to remove the cradle beams from the water. The adjacent ends of the lift beam sections shown in FIGURES 1 to 4, inclusive, can be raised to tilt the beams about the bearing rods on the winch ends of the beams. Either end of the beams of the lift shown in FIGURES 6 to 8, inclusive, can be raised sufiiciently to lift the projections out of the water. In both cases the beams should be in their raised positions when thus tilted.

When the lift shown in FIGURE 9 has been raised to its uppermost position, the beams can be pulled lengthwise and upward swinging of the lower ends of the suspension links, as shown in broken lines, will lift the beams out of the water. In the boat lift of FIGURE 10 the winch can be reeled in farther to shorten the tackle and draw the lower ends of the projections closer together. Such movement of the projections will buckle the beam upward until the lower ends of the projections are clear of the water, as shown in the upper broken line position of the beam and projections in FIGURE 10.

What is claimed is:

1. A boat lift for lifting a boat in a boat slip relative to decks at opposite sides of such slip, comprising a cradle beam including two beam sections disposed generally in lengthwise alignment, having their adjacent ends hingedly connected and depressible into the slip below a boat floating therein with the extreme ends of said beam sections supported from the respective decks at opposite sides of the slip, the adjacent ends of said beams having respective projections extending downwardly therefrom which are in spaced relationship when the adjacent ends of said beam sections are depressed into the slip, and pulling means connecting the lower portions of said projections and operable to draw such lower portions toward each other to swing said beam sections relatively to raise their adjacent ends for lifting the boat.

2. As the boat lift defined in claim 1, in which the pulling means includes tackle connecting the lower portions of the projections and a winch mounted on a portion of one of the beam sections remote from the other beam section and connected to said tackle for drawing the projections toward each other.

References @ited in the tile of this patent UNITED STATES PATENTS 636,445 McCabe Nov. 7, 1899 901,589 Burwell Oct. 20, 1908 1,534,364 Diaz Apr. 21, 1925 1,889,925 Leininger Dec. 6, 1932 2,281,595 Plant May 5, 1942 2,285,475 Valvsek June 9, 1942 2,733,823 Evans Feb. 7, 1956 2,963,176 Smith Dec. 6, 1960 2,975,868 Long Mar. 21, 1961 FOREIGN PATENTS 6,446 Great Britain July 4, 1833

Claims (1)

1. A BOAT LIFT FOR LIFTING A BOAT IN A BOAT SLIP RELATIVE TO DECKS AT OPPOSITE SIDES OF SUCH SLIP, COMPRISING A CRADLE BEAM INCLUDING TWO BEAM SECTIONS DISPOSED GENERALLY IN LENGTHWISE ALIGNMENT, HAVING THEIR ADJACENT ENDS HINGEDLY CONNECTED AND DEPRESSIBLE INTO THE SLIP BELOW A BOAT FLOATING THEREIN WITH THE EXTREME ENDS OF SAID BEAM SECTIONS SUPPORTED FROM THE RESPECTIVE DECKS AT OPPOSITE SIDES OF THE SLIP, THE ADJACENT ENDS OF SAID BEAMS HAVING RESPECTIVE PROJECTIONS EXTENDING DOWNWARDLY THEREFROM WHICH ARE IN SPACED RELATIONSHIP WHEN THE ADJACENT ENDS OF SAID BEAM SECTIONS ARE DEPRESSED INTO THE SLIP, AND PULLING MEANS CONNECTING THE LOWER PORTIONS OF SAID PROJECTIONS AND OPERABLE TO DRAW SUCH LOWER PORTIONS TOWARD EACH OTHER TO SWING SAID BEAM SECTIONS RELATIVELY TO RAISE THEIR ADJACENT ENDS FOR LIFTING THE BOAT.

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