AU2019100653B4

AU2019100653B4 - Lifting Device

Info

Publication number: AU2019100653B4
Application number: AU2019100653A
Authority: AU
Inventors: Tony Tuesley
Original assignee: Marine Stainless & Alloy Solutions
Current assignee: Marine Stainless & Alloy Solutions
Priority date: 2019-06-17
Filing date: 2019-06-17
Publication date: 2022-02-10
Anticipated expiration: 2027-06-17
Also published as: AU2019100653A4

Abstract

Lifting Device The present invention relates in general to a device for lifting boats or personal watercraft. The present invention is an operated platform that may be secured to a boat or a structure. The lifting device has a frame attached to a support, the frame having a pair of spaced upright hollow tubular members and a horizontal hollow tubular member extending between the upright tubular members. A moveable member is received within a central bore of each upright tubular member and a platform is mounted on the moveable member. The platform has an adjustable platform support which is adapted to engage with a hull of the watercraft. A motor assembly having a dual direction motor with a pair of flexible drive cables with first ends attached to opposing sides of a drive drum and second ends attached to an end of each moveable member. Upon rotation of the motor in a first direction, the platform is movable between a lowered position in which the platform support is below the surface of the water such that the watercraft is floated into position above the platform support, and upon rotation of the motor in a second direction the platform is moveable to a raised position in which the platform support engages the watercraft hull from below and lifts the watercraft clear of the water.

Description

Lifting Device

FIELD OF THE INVENTION

The present invention relates generally to a device for lifting boats or personal watercraft. In particular, the present invention relates to an operated platform that may be secured to a boat or a structure.

The present invention also extends to a device for lifting boats or personal watercraft that is capable of raising and lowering a platform in a substantially horizontal manner.

BACKGROUND OF THE INVENTION

It should be noted that reference to the prior art herein is not to be taken as an acknowledgement that such prior art constitutes common general knowledge in the art.

While dock mounted and transom mounted davits and lifts are well known, many have substantial shortcomings or are too large to be attached to a pleasure craft. Further still, many of the boat lifts were designed to raise and lower small inflatable boats or dinghies where weight distribution is not an important consideration. With the increased popularity of personal watercraft such as jet skis there is an increased need for a boat lift that is capable of raising and lowering personal watercraft in and out of the water.

Boat lifts are typically attached to the transom and/or the swim platform of large boats to launch or lift and carry the small watercraft next to the transom of the larger boats. Many of the available boat lifts have limitations and problems that affect their applications. For example, the older styles of boat lifts have used pulleys, and block and tackle arrangements with ropes or cables to raise and lower a cradle or platform. The use of ropes or cables between the pulleys can often become tangled and make the boat lift difficult to operate. In most cases they are also manually operated which is not desirable for a person standing on the transom or swim platform of the boat.

Many of the modern type of boat lifts require complex and expensive arrangements of hydraulic type cylinders to raise and lower a platform. The lift platforms are commonly mounted to the stern or swim platform of a boat via a hydraulic lift mechanism. Most boat lifts operate with one but preferably two hydraulic cylinders operating in tandem to provide the lift force required to raise and lower the platform with the watercraft located on the platform. The hydraulic cylinders are coupled together through the platform but generally attached to each lift arm of the platform. In use, if the load placed on the platform is not equally balanced one cylinder will lift the platform faster than the other cylinder. As the platform is raised or lowered and if the load is unbalanced the platform may move at an angle. This creates a dangerous situation because the boat or personal watercraft located upon the platform may slide off of the platform and cause injury to someone located nearby. Also, in most cases when using a separate cylinder to operate each lift arm the stroke of the cylinders need to be synchronized. This adds further expense to the system and also adds further items or componentry which can fail.

Another type of device for lifting boats or personal watercraft has a transom operating mechanism which uses a single rotary actuator instead of two hydraulic rams to raise or lower the lift arms. The single rotary actuator rotates a shaft which is connected by a pair of struts which link rotation of the shaft to both lift arms. The shaft is fabricated from marine grade stainless steel which does not have high resistance to fatigue-based failure. As such, failure can occur as a result of repetitive or cyclical torsional stresses applied to the shaft. This device is also problematic in that the extent of rotation of the shaft is not easily limited. Mechanical stops are required on the shaft to operatively stop the shaft against the frame of the lifting device to achieve accurate movement limitation. Repetitive striking of the stops or posts can result in failure through fatigue.

Another problem associated with lifting devices which utilise hydraulically driven actuators is the requirement for some form of locking mechanism. Typically slow pressure drops in the hydraulic lines feeding fluid and pressure to the actuators can cause the platform to drop or lower. A locking mechanism is required to prevent the inadvertent movement of the device for lifting boats or personal watercraft.

Clearly it would be advantageous if a device for lifting boats or personal watercraft could be devised that helped to at least ameliorate some of the shortcomings described above. In particular, it would be beneficial to provide a device for lifting boats or personal watercraft that is capable of raising and lowering a platform in a substantially horizontal manner.

SUMMARY OF THE INVENTION

In accordance with a first aspect, the present invention provides a lifting device for raising and lowering a watercraft, the lifting device comprising: a frame attached to a support, the frame having a pair of spaced upright hollow tubular members and a horizontal hollow tubular member extending between the upright tubular members, the pair of upright tubular members and the horizontal tubular member forming a central bore extending through the frame, a moveable member with an end received within the central bore of each upright tubular member; a motor assembly having a dual direction motor, the motor assembly having a cable drum attached to a drive shaft of the dual direction motor, the motor assembly is mounted on the horizontal tubular member with the cable drum aligned to rotate within the central bore of the horizontal tubular member of the frame; a pair of flexible drive cables having first ends attached to opposing sides of the drive drum and second ends attached to the end of each moveable member in the central bore of each upright tubular member; a platform mounted on another end of the moveable member, the platform having an adjustable platform support engageable with a hull of the watercraft; and wherein upon rotation of the motor in a first direction, the platform is movable between a lowered position in which the platform support is below the surface of the water such that the watercraft is floated into position above the platform support, and upon rotation of the motor in a second direction the platform is moveable to a raised position in which the platform support engages the watercraft hull from below and lifts the watercraft clear of the water.

Preferably, the lifting device may further comprise a roller mounted for rotation at a junction formed between each upright tubular member and the horizontal tubular member, each roller is adapted to guide the flexible drive cables during rotation of the motor and the raising and lowering of the platform.

Preferably, the frame may further comprise a mounting bracket attached to an end of each upright tubular member, each mounting bracket being affixable to the support. Preferably, the moveable member may further comprise an arm extending vertically from each moveable member each arm connecting each moveable member to the platform.

Preferably, the adjustable support engageable with the hull of the watercraft may further comprise a first and a second adjustable carriage to support the watercraft thereon in a substantial level position while the platform and the moveable member are being raised and lowered. The first and second carriages may be mounted for movement along each arm extending vertically from each moveable member. Each one of the first and second carriages may have a mounting assembly located on each arm, such that each of the first and second carriages extend substantially perpendicular between each arm and substantially parallel to each other. Each mounting assembly may allow an angle of the first and second adjustable carriages to be adjusted to suit a slope or angle of the hull of the watercraft supported on the platform.

Preferably, the mounting assembly and the first and second carriages in combination may cause a top side of the watercraft to be maintained in a generally horizontal orientation during movement of the platform between the raised and lowered positions and vice versa.

Preferably, the arms extending vertically from each moveable member may be pivotally mounted to each moveable member, the pivotal mounting allowing the platform to be rotated towards the upright tubular members when not in use.

Preferably, the support may be any one of a horizontally extending rearward surface of a watercraft or a watercraft dock.

Preferably, rotation of the motor in the first or second directions may wind or unwind the pair of flexible cables around the cable drum, when the pair of flexible cables are wound on the cable drum, the second ends of the flexible cables attached to the end of each moveable member moves the platform vertically upward while maintaining the watercraft on the platform in a horizontal position and when the pair of flexible cables are unwound from the cable drum, the second ends of the flexible cables attached to the end of each moveable member moves the platform vertically downwards while maintaining the watercraft on the platform in a horizontal position.

Preferably the second ends of the flexible drive cables may have a loop end through which a fastener is secured therethrough and affixed to the end of each moveable member. The flexible drive cables may be a polyester reinforced cable.

Preferably, the frame, the moveable member, and the platform may be constructed of a marine grade stainless steel. Preferably, the platform may be formed as a frame with a marine grade wooden decking extending between opposing sides of the frame.

Preferably, the dual direction motor may be any one of an electric motor, a hydraulic motor or a pneumatic motor. The electric motor may comprise a DC electric motor with a reduction gear assembly connected to the cable drum.

Preferably, the lifting device may further comprise a control device in communication with the dual direction motor, the control device is configured to control the rotation of the dual direction motor to move the platform between the raised position and the lowered position.

Preferably, each upright hollow tubular member may have a first end for receiving the moveable member therein, the first end has a bush received within the first end for guiding movement of each moveable member as it moves within the respective upright hollow tubular member. The moveable member may further comprise a stop positioned for limiting the movement of the moveable member within the upright hollow tubular member.

In accordance with a further aspect, the present invention provides a combination comprising: a boat having a stern and a swim platform mounted to the stern, the swim platform extending outwardly from the stern; and a lifting device mounted to the stern adjacent the swim platform, the lifting device comprising: a frame attached to the swim platform, the frame having a pair of spaced upright hollow tubular members and a horizontal hollow tubular member extending between the upright tubular members, the pair of upright tubular members and the horizontal tubular member forming a central bore extending through the frame, a moveable member with an end received within the central bore of each upright tubular member; a motor assembly having a dual direction motor, the motor assembly having a cable drum attached to a drive shaft of the dual direction motor, the motor assembly is mounted on the horizontal tubular member with the cable drum aligned to rotate within the central bore of the horizontal tubular member of the frame; a pair of flexible drive cables having first ends attached to opposing sides of the drive drum and second ends attached to the end of each moveable member in the central bore of each upright tubular member; a platform mounted on another end of the moveable member, the platform having an adjustable platform support engageable with a hull of a watercraft; and wherein upon rotation of the motor in a first direction, the platform is movable between a lowered position in which the platform support is below the surface of the water such that the watercraft is floated into position above the platform support, and upon rotation of the motor in a second direction the platform is moveable to a raised position in which the platform support engages the watercraft hull from below and lifts the watercraft clear of the water.

Preferably, the combination may further comprise any one of the features of the lifting device of the first aspect.

In accordance with a still further aspect, the present invention provides a method of operating a lifting device for raising and lowering a watercraft, wherein the lifting device comprises: a frame attached to a support, the frame having a pair of spaced upright hollow tubular members and a horizontal hollow tubular member extending between the upright tubular members, the pair of upright tubular members and the horizontal tubular member forming a central bore extending through the frame, a moveable member with an end received within the central bore of each upright tubular member; a motor assembly having a dual direction motor, the motor assembly having a cable drum attached to a drive shaft of the dual direction motor, the motor assembly is mounted on the horizontal tubular member with the cable drum aligned to rotate within the central bore of the horizontal tubular member of the frame; a pair of flexible drive cables having first ends attached to opposing sides of the drive drum and second ends attached to the end of each moveable member in the central bore of each upright tubular member; and a platform mounted on another end of the moveable member, the platform having an adjustable platform support engageable with a hull of a watercraft; the method comprising: operating the motor for rotating the cable drum with the flexible cables attached thereto in a first direction, wherein the first direction rotation of the cable drum and cables results in a lowering of the platform to a lowered position of the lifting device; floating the watercraft into position above the platform support; and operating the motor for rotating the cable drum with the flexible cables attached thereto in a second direction, wherein the second direction rotation of the cable drum and cables results in a raising of the platform and the watercraft is positioned on the platform support and moved to a raised position on the lifting device and clear of the water.

Preferably, the method may further comprise any one of the features of the lifting device of the first aspect.

Any one or more of the above embodiments or preferred features can be combined with any one or more of the above aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood more fully from the detailed description given hereinafter and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken to be limitative to the invention, but are for explanation and understanding only. Fig. 1 shows a perspective view of a lifting device for raising and lowering a watercraft attached to a boat in accordance with an embodiment of the present invention; Fig. 2 shows a perspective view of the lifting device of Fig. 1 with the platform in the raised position; Figs. 3A to 3D show rear, end, top and bottom views of the lifting device of Fig. 2; Fig. 4 illustrates a front perspective view of the lifting device of Fig. 1 with the platform in the lowered position; Figs. 5A to 5C show enlarged views of the connection of one of the moveable members and an upright tubular member; Fig. 6 shows an enlarged view of the dual direction motor installed on the horizontal tubular member; and the remote controller connected to one side of the motor; Fig. 7 shows the roller over which the cable is entrained within the tubular members of the frame of the lifting device; Fig. 8 illustrates an enlarged side view of the platform of the lifting device in accordance with an embodiment of the present invention; Fig. 9 shows an enlarged side view of a platform of the lifting device in accordance with a further embodiment of the present invention;

Fig. 10 shows a still further embodiment of a platform in accordance with the present invention; and Fig. 11 shows a lifting device with some accessories attached to the upright and horizontal members in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description, given by way of example only, is described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments.

The present invention was designed to provide a lifting device 20 configured to be connected to a structure 10 and adapted to raise and lower watercraft such as small inflatable boats or dinghies and personal watercraft such as jet skis from the water. As shown in Fig. 1, reference numeral 20 generally indicates an exemplary embodiment of a lifting device 20 mounted on an appropriate structure, such as boat 10. However, it should also be apparent to the skilled person that the support 10 to which the lifting device 20 can be connected to includes piers, solidly mounted proximate a body of water. It will be understood that the pier may constitute a portion of a dock or, alternatively, other structure (not shown) may be provided adjacent the water, mounted on a sea wall or the like for securement of the lifting device 20 of the present invention thereto.

The lifting device 20 includes a platform 70, wherein the platform is configured to receive a boat or personal watercraft thereon. A boat is taken to refer to any small boat or dinghy which could be used by an operator when the pleasure craft is anchored away from a dock and the only access is by a smaller craft. A frame 30 is carried on the stern transom 12 extending from the body 11 at the aft of a boat 10 substantially generally above the water line (not shown). The frame 30 has a pair of spaced upright hollow tubular members 32 and a horizontal hollow tubular member 31 extending between the upright tubular members 32. A motor assembly 50 is mounted centrally on the horizontal tubular member 31 with a drive drum 63 on one end of the motor assembly 50 being located within a central bore which extends through the upright and horizontal tubular members 31, 32. A moveable member 81 is slideably received within each upright member 32, the moveable members 81 have the platform 70 mounted thereon. The platform 70 is designed to receive a watercraft such as small inflatable boats or dinghies and personal watercraft such as jet skis thereon. A pair of flexible drive cables 56 are attached to the motor drum 63. An end of each cable 56 is attached on opposing sides of the drive drum 63 and the opposite end of the cable 56 is attached to an end of each moveable member 81. Upon rotation of the motor 55 in a first direction, the platform 70 is movable to a lowered position in which the platform support 79 is below the surface of the water such that the watercraft is floated into position above the platform support 79. Upon rotation of the motor 55 in a second direction the platform 70 is moveable to a raised position in which the platform support 79 engages the watercraft hull from below and lifts the watercraft clear of the water.

In the raised position the platform 70 would be level with the stern transom or deck 12 of the boat 10. In the lowered position the platform 70 is at or below the waterline (not shown). When the platform 70 is in the raised position, both the platform 70 and the deck 12 of the boat 10 are in substantially the same plane. When the platform 70 is in the lowered position the plane of the platform 70 is substantially parallel to the plane of the deck 12 of the boat 10.

Figs. 2 and 3A to 3D show the lifting device 20 with the platform 70 in the raised position. The platform 70 is displaceable between a raised position (shown in Figs. 2 and 3A to 3D) and a lowered position (shown in Fig. 4). In the raised position the moveable tubular members 81 are substantially received within the upright members 32 of the frame 30. Each moveable member 81 is a hollow cylindrical stainless steel tube. Each upright member 32 is a hollow stainless steel tube with a central bore having an opening 41 at the bottom end for receiving a rubber bush 82, 83 for guiding the movement of the movable member 81 therein. The bottom end of each upright member 32 has a mounting bracket 35 with a base plate 37 for mounting the frame 30 to the support 12. The base plate 37 has apertures 38 for receiving fasteners 40 therein. The fasteners 40 are marine grade fasteners such as stainless steel or bronze fasteners or the like and are utilised to mount the lifting device 20 to the stern transom 12. Also mounted between the rear side of each upright member 32 and the mounting bracket 35 are support members 33, 34. The support members 33, 34 support and reinforce the frame 30 in a substantially upright position on the mounting brackets 35.

At the junction of each upright member 32 and the horizontal member 31 a roller 36 is mounted for rotation. Each roller 36 is pivotally mounted externally of the junction between each upright member 32 and the horizontal member 31 but the roller 36 has a surface which extends internally to the central bore at or adjacent the junction. As will be described in more detail below the flexible cables 56 are located within the central bore of the upright members 32 and the horizontal member 31 and each cable 56 is entrained over each roller 36, each roller 36 guiding the movement of each cable 56. The horizontal member 31 like the upright members 32 is a hollow stainless steel tube with a central bore therein.

Mounted centrally on the horizontal member 31 is the motor assembly 50. The motor assembly 50 has a cylindrical motor housing 51 with an access cover 52 affixed to the top of the housing 51. The motor assembly 50 also has a DC electric motor 55 with a central drive shaft (not shown). Attached to the central drive shaft is a cable drum 63, the cable drum 63 being located and aligned with the central bore of the horizontal member 31. Each cable 56 has one end attached to opposite sides of the drum 63 and another end attached to the end 85 of each moveable member 81. By attaching the cables 56 to opposing sides of the drum 63 ensures that cables 56 when wound or unwound on the drum 63 will move the attached moveable members 81 in the same direction. As will be described further below a controller 60 is attached by cable 59 and connector 54 to a socket 53 located on the side of the housing 51. The controller 60 allows an operator to remotely raise and lower the platform 70.

Upon rotation of the cable drum 63 by the motor 55 in a clockwise direction, the cables 56 are wound around the drum 63 and the platform 70 would be in the raised position as illustrated in Figs. 2 and 3A to 3D. Upon rotation of the motor 55 in an anti-clockwise direction, the cables 56 are unwound from the cable drum 63 which allows the cables to be guided over the rollers 36 to lower the platform 70. As the cables 56 move over the rollers 36 the moveable members 81 guided by the bushes 82, 83 located at the bottom of each upright member 32 move vertically downwards and substantially out of the central bore in each upright member 32. As each moveable member 81 moves down the platform 70 attached to the moveable members 81 also moves vertically down. To raise the platform 70 the motor 55 is again driven clockwise and the cables 56 are wound around the cable drum 63 returning the moveable members 81 to be located within the upright members 32 and raising the platform 70. Alternatively, the directions of rotation may be reversed and the motor 55 upon rotation in an anti-clockwise direction, the cables 56 are wound around the drum 63 and the platform 70 would be in the raised position. Upon rotation of the motor 55 in a clockwise direction, the cables 56 are unwound from the cable drum 63 which allows the cables to be guided over the rollers 36 to lower the platform 70.

The platform 70 is attached to beams or arms 90 which extend substantially perpendicular from the bottom of each moveable member 81. The platform 70 has a stainless steel frame 74 upon which the floor 72 is mounted on a floor frame 71. Mounted above the floor 72 are the platform supports or cradle rails 79 which are adapted to carry the watercraft hull of the watercraft such as small inflatable boats or dinghies and personal watercraft such as jet skis.

The beams or arms 90 extend out in front of the frame 30 to receive the platform 70 and the load which is to be raised or lowered. In the preferred embodiment, the arms 90 are provided with a pair of wooden rails 79 for receiving a jet ski or other small boat. The rails 79, which are oriented perpendicularly to the arms 90, are coupled to the arms 90 by way of mounting brackets 93, 95. The mounting brackets 93, 95 are moveable along the arms

90 to allow the distance between the rails 79 to be varied to suit the hull size of the jet ski or small boat. The rails 79 are attached to the brackets 93, 95 by posts 75 which extend up between gaps, between the floor 72 and are located at either end of the platform 70. Opposing ends of the rails 79 are seated within a bracket 78 to which the posts 75 are attached. The posts 75 are received within adjustable mounts 76, 98 which allow the vertical height of the posts 75 and the rails 79 above the floor 72 to be individually adjusted to suit the required angle of the rails 79 for a particular jet ski or small boat.

The rear mounting brackets 93 on each arm 90 are directly connected to the post 75 by mount 98. To position the front rail 79 outside of the platform 70 and externally of the floor frame 71, the adjustable mount 76 is mounted on an extension piece 77 extending from the front mounting bracket 95 on each arm 90. The extension piece 77 has at one end the adjustable mount 76 and at the opposing end a vertical attachment member 92 which is received within the moveable bracket 95. The rails 79 are both adjustable in the distance between each rail 79 and in individual heights above the platform 70 by adjustment of each mounting post 75 in the mounts 76, 98.

Figs. 3A to 3D show rear, end, top and bottom perspective views of the lifting device 20 in the raised position. Fig. 3A is a rear view which shows the platform 70 with the stainless steel frame 74 which extends around the periphery of the platform 70 and upon which the floor 72 is mounted on a floor frame 71. While marine grade stainless steel is preferable for both frames 71, 74, an alternative such as aluminium may also be used for the frames 71, 74. The floor 72 is illustrated as marine grade floor boards 72, such as teak attached to the floor frame 71 by any suitable fastener (not shown). Alternatively, the floor boards 72 may also be aluminium or any composite material which is suitable. Likewise, the rails 79 may be constructed from marine grade wood, aluminium or any composite material. Each rail 79 may have an anti-slip coating or padded material applied to a top surface of each rail 79 to provide better engagement with the hull of the watercraft as well as prevent any damage to the hull of the watercraft during raising and lowering of the lifting device 20. As a further alternative, the rails 79 could be manufactured from laminated fibreglass.

The rails 79 in Fig. 3A are positioned running perpendicular to the floor 72 with each bracket 78 adjusted to be at the same height above the floor 72. This aligns each rail 79 to run parallel with the floor 72. As illustrated in Fig. 3B the brackets 78 at the distal ends of the rails 19 are positioned vertically closer to the floor 72 than the brackets 78 at the proximal ends of the rails 79. While the rails 79 are still positioned perpendicular to the floor 72 the rails 79 are no longer running parallel to the floor 72. In this embodiment, the positioning of the rails 79 allows the watercraft to be more easily positioned on the rails 79 as it approaches from the distal end of the platform 70. It also ensures that when the watercraft is placed on the rails 79, the angle of the rails 79 and the watercraft on the rails 79, allows any water which may have been retained in the watercraft to efficiently drain therefrom. The angling of the rails 79 can also be positioned to suit the contour or shape of the hull of the watercraft to be positioned on the lifting device 20.

As illustrated in Figs. 3A and 3B are the mechanical stops or plates 80 positioned on each moveable member 81 to prevent the moveable member 81 from being completely withdrawn from within each upright member 32. The stops or plates 80 abut against the bush 82 and are secured to the bottom of each mounting bracket 35 by fasteners (not shown). This secures the bushes 82 and the moveable members 81 from being removed from within each upright member 32. Each plate 80 has a central aperture which allows the moveable members 81 to move up and down therethrough and allow the platform 70 to be raised and lowered. Fig. 3B also shows the brace 91 which is connected from the bottom end of each moveable member 81 to the free end of each arm 90 on the platform 70.

Fig. 3C shows a top view of the lifting device 20 which clearly shows the apertures 38 in the base plates 37 located on each side of the frame 30. Each aperture 38 is adapted to receive a fastener 40 therein for securing the lifting device 20 to the support. As illustrated in Fig. 1 the support is the deck 12 of the boat 10. Fig. 3C also illustrates the alignment of one of the cables 56 guided within the central bore of the horizontal member 31. As described above each cable 56 is attached to opposing sides of the drum 63 which is connected to the motor 55.

Fig. 3D shows a bottom view of the lifting device 20. Extending between each arm 90 and approximately through the midline axis of the platform 70 is the floor board mount 84. Each floor board 72 is fixed to the floor board mount 84 by a fastener passing through apertures in the floor board mount 84. With the exception being two panels 72 which are attached to the floor frame 71 on either end of the platform 70 and on the outer sides of each arm 90.

Fig. 4 shows the lifting device 20 with the platform 70 in the lowered position. In this position the platform 70 and the rails 79 would be located below the surface of the water such that the watercraft can be floated into position above the rails 79. In this position the moveable member 81 is fully extended to be positioned with an end of each moveable member 81 positioned adjacent the bottom of each upright member 32. The position of each bracket 78 on the platform 70 highlights the varied positions possible for the rails 79. Also highlighted in Fig. 4 is the position of the cables 56 attached to opposing sides of the motor 55 and how they are positioned within each member 31, 32. Each cable 56 is entrained over a roller 36 positioned at the junction formed between each upright member 32 and opposing ends of the horizontal member 31. The rollers 36 effectively change the direction which the cables 56 are moving from horizontal to vertical. Ends 57 of each cable 56 are attached to an end of each moveable member 81. Rotation of the motor 55 will move the cables 56 and the moveable members 81 up and down within the central bore of the upright members 32. The moveable members 81 being guided for movement within the upright members by bushes 82, 83 positioned within an opening at the bottom of each upright member 32.

Rotation of the motor 55 in clockwise or anti-clockwise directions will move the platform 70 vertically up and down the lifting device 20. The design ensures that as the platform 70 is moved vertically a watercraft positioned on the rails 79 of the platform 70 is maintained in a substantially level position.

Figs. 5A to 5C show detailed views of the movement of the moveable members 81 in the upright members 32. Fig. 5B shows the lifting device 20 in the fully raised position with the moveable member 81 received within the upright member 32 and the stop plates 80 of the moveable member 81 abutted against the bottom of the bush 82. Located on the bottom end of the moveable member 81 is the brace 91 and the arm 90 extending perpendicular to and in front of the moveable member 81. As previously described the platform 70 is mounted on each arm 90.

Fig. 5A shows the lifting device 20 in a fully extended position with the platform 70 in the lowered position. As was illustrated in Figs. 4 and 5A, an end of each moveable member 81 is located adjacent the bottom end of each upright member 32. Fig. 5A also illustrates the mounting brackets 35, base plate 37 and fasteners 40 extending through the apertures 38 in the base plate 37. The fasteners 40 secure the lifting device 20 to a support. The support as illustrated in Fig. 1 is a boat 10 or could include piers mounted proximate a body of water, a dock or, alternatively, any other structure provided adjacent a body of water.

As shown in Fig. 5C the moveable member 81 has been removed from within the upright member 32 to show the connection of the end of a cable 56 to the moveable member 81. Each cable 56 has a loop 58 attached at the end adjacent the connection to the moveable member 81. The loop 58 is attached to the end 85 of each moveable member 81 by passing a fastener 57 through the loop 58 and then securing the fastener 57 to the end 85 of the moveable member 81. Also illustrated in Fig. 5C, the bush 82, 83 consists of lip 82 which in use abuts against the bottom ends of the opening 41 of the upright members 32 and extending from the bottom of the mounting bracket 35.

Fig. 6 illustrates an enlarged view of the motor assembly 50 mounted centrally on the horizontal member 31. The cylindrical motor housing 51 is mounted to position the DC motor 55, cable drum 63 and the cables 56 within the central bore of the horizontal member 31. The cylindrical housing 51 has threaded apertures 62 located in a top surface for receiving fasteners to secure the motor cover 52 in place on the cylindrical housing 51. The cover 52 has corresponding apertures 61 in the cover 52 for receiving fasteners (not shown) to secure the cover 52 to the housing 51. Also shown attached to one side of the cylindrical housing 51 is the plug base 53 for receiving the connector 54 attached to wiring harness 59 to connect the remote controller 60 to allow an operator to raise and lower the platform 70 of the lifting device 20. By way of example only the controller 60 simply has two operating buttons which allow the operator to either raise or lower the platform 70 accordingly.

Fig. 7 shows the roller 36 located at the junction between each end of the horizontal member 31 and the upright members 32. The roller 36 is mounted for rotation in mounting plates 42 by a pivot pin 43. While the roller 36 is mounted externally of the central bore in the members 31, 32, a surface of the roller 36 extends into the central bore to guide and change the movement of the cables 56 from horizontal to vertical. Each cable 56 is entrained over the outer surface of the roller 36. The roller 36 also positions the cables 56 so that they are not in contact with the surface of the central bores in the members 31, 32.

Fig. 8 shows an enlarged view of one of the arms 90 extending perpendicularly from the front of the moveable member 81. In particular, this figure shows detail of the connection of the posts 75 used to position the rails 79 above the platform 70. The sliding mounts 93, 95 mounted on the arm 90 are identical on both ends of platform 70. Each mount 93, 95 is moveable along the arm 90 to allow the location of the rails 79 to be positioned to suit the width of the hull of the watercraft to be supported on the rails 79. Each bracket 93, 95 has fasteners 97 to secure the bracket 93, 95 in position on the arm 90. Each rear bracket 93 located on the arm 90 has an adjustable mount 98 which allows the vertical position of the corresponding rail 79 to be adjusted individually. The posts 75 extend through the adjustable mount 98 and are secured in position by fasteners 94 on the mount 98. This allows each end of the rear rail 79 to be adjusted vertically with respect to the floor 72 to suit the watercraft to be supported on the rail 79. The front brackets 95 on the arm 90 are designed to mount the front rail 79 externally with respect to the front edge of the platform 70. The bracket 95 has an adjustable mount 99 which attaches the vertical member 92 of the extension arm 77 within the bracket 99. The vertical member 92 is secured within the mount 99 by fastener 96. The opposing end of the extension arm 77 has the adjustable mount 76 positioned to receive the post 75 located on either end of the front rail 79. The posts 75 extend through the adjustable mount 76 and are secured in position by fasteners 100 on the mount 76. This allows each end of the front rail 79 to be adjusted vertically with respect to the floor 72 to suit the watercraft to be supported on the front rail 79. Each end of the rails 79 is both adjustable horizontally with respect to the floor 72 of the platform 70 and vertically with respect to each rail 79. That is, each end of the rails 79 and the adjustable posts 75 with the brackets 78 which receive the rails 79 is adjustable in height with respect to a plane passing through the platform 70.

Fig. 9 illustrates a further embodiment of the platform 70 in accordance with the present invention. The platform in this embodiment has been adapted to be hinged to allow the platform to pivot in the direction of arrow A so that when the platform 70 is not in use the platform can be pivoted to be positioned beside the upright members 32 of the frame 30. This also has advantages for transportation of the lifting device 20 to achieve a smaller footprint for transport. Each arm 90 of the platform 70 has a hinged mount 105 located adjacent the moveable members 81. A pivot pin 106 allows the arms 90 to be rotated in an upward direction of arrow A to position the platform 70 beside the frame 30. The only other difference between this embodiment and the previous embodiment is the removal of the brace 91 from between the bottom end of each moveable member 81 and the front edge of the arm 90. This allows the arms 90 to be pivoted.

Fig. 10 shows a further embodiment of the lifting device 20 with platform 110. In this embodiment, the floor frame 71 and floor boards 72 have been removed. Also, the rails 79 are both moveably mounted on each arm 90 by brackets 111, 112. The brackets 112 are attached to the rear rails 79 to allow the rail 79 to be moved along the arms 90. Likewise, the brackets 111 are attached to the front rail 79 to allow the front rail 79 to be moved along the arms 90. The brackets 111 are secured to each arm by fasteners 115 and the brackets 112 are secured to the arms 90 by fasteners 116. Each bracket 111 has an adjustable mount 113 for receiving the posts 75 therein. The adjustable mount 113 allows the vertical position of the rail 79 to be adjusted individually at either end of the rail 79. Likewise, the brackets 112 have an adjustable mount 114 for receiving posts 75 therein. The adjustable mount 114 allows the vertical position of the rail 79 to be adjusted individually at either end of the rail 79.

Fig. 11 illustrates a further embodiment of the lifting device 20 which incorporates some accessories 120, 121, 122 which can be utilised when the lifting device 20 is mounted on the stern 12 of a boat 10. For example, a barbeque 120, bait tray 121 and rod holders 122 are mounted on the horizontal member 31 and upright members 32 respectively. The rod holders 122 are mounted to each upright member 32 by mounting brackets 123 extending from an outer surface of each upright member 32. While the above accessories have been described, other accessories could be incorporated with the lifting device 20 in accordance with the present invention. For example, a gas bottle to supply gas to the barbeque 120 could also be mounted on one of the upright members 32. Also, a light could be mounted on an upright member attached to the horizontal member 31.

The present invention also provides a method of operating the lifting device 20 to raise and lower a watercraft. The lifting device 20 comprises all of the features already mentioned in relation to Figs. 1 to 11. The method consists of operating the motor 55 to rotate the cable drum 63 with the flexible cables 56 attached thereto in a first direction. For example, in a clockwise direction which rotates the cable drum 63 and cables 65 and results in the lowering of the platform 70 to a position in which the platform support rails 79 are positioned below the surface of the water such that the watercraft can be floated into position above the platform support rails 79. The operator using the controller 60 rotates the motor 55 and the cable drum 63 with the flexible cables 56 attached thereto in a second direction. For example, in an anti-clockwise direction which rotates the cable drum 63 and cables 56 and results in the raising of the platform 70 to a position which firstly moves the platform support rails 79 into contact with the hull of the watercraft and then continues to raise the watercraft clear from the water to a position where the platform 70 sits approximately level with the stern transom or deck 12 of the boat 10.

The motor 55 is a dual direction DC motor with a drive shaft directly coupled to the cable drum 63. Alternatively, and to provide additional drive force the drive shaft may be connected firstly through a reduction gear and then from the reduction gear to the cable drum 63. In a preferred embodiment, the motor 55 is a DC electric winch which can be driven in both clockwise and anti clockwise directions. Alternatively, other drive sources such as hydraulic or pneumatic sources could be used to power a suitable motor 55.

The flexible cables 56 are a polyester reinforced flexible cable or the like. Alternatively, the flexible cables 56 may be a polyethylene fiber reinforced cable or any cable which is lightweight, strong and flexible.

The lifting device 20 is mainly constructed from marine grade stainless steel and timbers. The material must be able to resist corrosive effects that are common in a water environment. By way of example marine grade stainless steel is achieved by adding special alloying elements to the steel in order to defend against corrosion. Alternatively, the lifting device 20 may incorporate other materials such as marine grade aluminium, bronze and composite plastic materials to replace the floor boards.

ADVANTAGES

The present invention provides a lifting device configured to be connected to a structure and adapted to raise and lower watercraft such as small inflatable boats or dinghies and personal watercraft such as jet skis from the water.

The design of the present invention provides a lifting device for lifting boats or personal watercraft from the water that is capable of raising and lowering a platform in a substantially horizontal manner. By locating the moveable member within the upright members of the frame and attaching the flexible cables to opposing sides of the cable drum ensures that as the motor rotate clockwise or anti-clockwise and winds and unwinds the cables, the platform is maintained substantially horizontal. This is particularly advantageous for lifting personal watercraft such as jet skis which are not evenly weight distributed over the length of the craft. The direct coupling of the cables to the ends of the moveable member ensures that as the platform is raised and lowered the platform will remain substantially level and not cause any binding or jamming issues that previous designs have suffered.

By containing the flexible cables within the upright and horizontal member ensures that the cables are always constrained by the central bores within the upright and horizontal members. This allows the lifting device to be easily installed on the support. The mounting brackets extending from the bottoms of the upright members allow easy installation especially to the stern transom of a boat. The addition of the rollers ensures a smooth change of direction for the cables and maintains the cable spaced from the surface of the central bore.

The present invention has been sized to allow the lifting device to be mounted to any boat or pleasure craft which has a stern platform or swimming platform.

In a preferred embodiment, the present invention provides a dual direction DC electric motor to raise and lower the platform of the lifting device. This design is not complex or expensive when compared with comparative arrangements which use hydraulic type cylinders to raise and lower a platform. The design does not require any locking devices to secure the platform in the raised position.

In one embodiment a hinged platform provides a number of advantages over the presently known lift platforms. By being able to fold the platform up against the frame means a much smaller package for transporting the device to purchasers. It also allows the platform when mounted on a boat to be pivoted to position the platform vertically up against the frame of the lifting device. This ensures that there is only a minimal addition to the overall length of the boat which is particularly important when the boat is moored. A boat is typically secured to a mooring to forestall free movement of the boat on the water. Each mooring or berth has a size or length restriction for the particular boat to be moored, if the boat exceeds this size the owner may be required to purchase a larger more expensive berth. It is also important that no part of the boat extends over a berth walkway, particularly when the boat is moored stern in. By having a hinged lifting device ensures that no part of the boat extends over a walkway and that there is no requirement to move to another more expensive mooring.

VARIATIONS

It will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein defined in the appended claims.

As used herein the term "and/or" means "and" or "or", or both.

As used herein "(s)" following a noun means the plural and/or singular forms of the noun.

The term "boat" refers to any aquatic vehicle of any size or type including, but not limited to, boats, yachts, pleasure craft, etc.

The term personal watercraft refers to a recreational watercraft that the rider sits or stands on, rather than inside of, as in a boat.

In this specification, adjectives such as first and second, left and right, top and bottom, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one or more of that integer, component, or step etc.

The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The invention is intended to embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the scope of the above described invention.

In the specification the term "comprising" shall be understood to have a broad meaning similar to the term "including" and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term "comprising" such as "comprise" and "comprises".

Claims

1. A lifting device for raising and lowering a watercraft, the lifting device comprising: a frame attached to a support, the frame having a pair of spaced upright hollow tubular members and a horizontal hollow tubular member extending between the upright tubular members, the pair of upright tubular members and the horizontal tubular member forming a central bore extending through the frame; a moveable member with an end received within the central bore of each upright tubular member; a motor assembly having a dual direction motor, the motor assembly having a cable drum attached to a drive shaft of the dual direction motor, the motor assembly is mounted on the horizontal tubular member with the cable drum aligned to rotate within the central bore of the horizontal tubular member of the frame; a pair of flexible drive cables having first ends attached to opposing sides of the drive drum and second ends attached to the end of each moveable member in the central bore of each upright tubular member; a platform mounted on another end of the moveable member, the platform having an adjustable platform support engageable with a hull of the watercraft; and wherein upon rotation of the motor in a first direction, the platform is movable between a lowered position in which the platform support is below the surface of the water such that the watercraft is floated into position above the platform support, and upon rotation of the motor in a second direction the platform is moveable to a raised position in which the platform support engages the watercraft hull from below and lifts the watercraft clear of the water.

2. A lifting device as claimed in claim 1, wherein the moveable member further comprises an arm extending vertically from each moveable member each arm connecting each moveable member to the platform.

3. A lifting device according to claim 2, wherein the arms extending vertically from each moveable member are pivotally mounted to each moveable member, the pivotal mounting allowing the platform to be rotated towards the upright tubular members when not in use.

4. A lifting device according to claim 1, wherein each upright hollow tubular member has a first end for receiving the moveable member therein, the first end has a bush received within the first end for guiding movement of each moveable member as it moves within the respective upright hollow tubular member.

5. A combination comprising: a boat having a stern and a swim platform mounted to the stern, the swim platform extending outwardly from the stern; and a lifting device mounted to the stern adjacent the swim platform, the lifting device comprising: a frame attached to the swim platform, the frame having a pair of spaced upright hollow tubular members and a horizontal hollow tubular member extending between the upright tubular members the pair of upright tubular members and the horizontal tubular member forming a central bore extending through the frame; a moveable member with an end received within the central bore of each upright tubular member; a motor assembly having a dual direction motor, the motor assembly having a cable drum attached to a drive shaft of the dual direction motor, the motor assembly is mounted on the horizontal tubular member with the cable drum aligned to rotate within the central bore of the horizontal tubular member of the frame; a pair of flexible drive cables having first ends attached to opposing sides of the drive drum and second ends attached to the end of each moveable member in the central bore of each upright tubular member; a platform mounted on another end of the moveable member, the platform having an adjustable platform support engageable with a hull of a watercraft; and wherein upon rotation of the motor in a first direction, the platform is movable between a lowered position in which the platform support is below the surface of the water such that the watercraft is floated into position above the platform support, and upon rotation of the motor in a second direction the platform is moveable to a raised position in which the platform support engages the watercraft hull from below and lifts the watercraft clear of the water.

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