U.S. patent application number 11/690732 was filed with the patent office on 2008-01-10 for failsafe watercraft lift with convertible leveling system.
This patent application is currently assigned to SUNSTREAM CORPORATION. Invention is credited to Kenneth E. Hey, Bryce M. Kloster.
Application Number | 20080008528 11/690732 |
Document ID | / |
Family ID | 38523343 |
Filed Date | 2008-01-10 |
United States Patent
Application |
20080008528 |
Kind Code |
A1 |
Hey; Kenneth E. ; et
al. |
January 10, 2008 |
FAILSAFE WATERCRAFT LIFT WITH CONVERTIBLE LEVELING SYSTEM
Abstract
A watercraft lift for raising and lowering a watercraft in
water, including a buoyant pontoon, a lifting cradle and at least
one pivot arm. The lifting cradle includes at least one air tank
and a support bunk configured to receive and support the
watercraft. The air tank has an internal chamber configured to
receive and release pressurized air. The internal chamber has
sufficient internal volume that when sufficient pressurized air is
received therein the air tank has sufficient buoyancy to lift the
lifting cradle to a raised position with the watercraft out of the
water when positioned on the support bunk and that when sufficient
pressurized air is released from the internal chamber the air tank
loses sufficient buoyancy to sink the lifting cradle to a lowered
position sufficiently submerged to receive and deploy the
watercraft. The pivot arm is pivotally connected to the pontoon and
pivotally connected to the lifting cradle to guide movement of the
lifting cradle between the lowered position and the raised
position.
Inventors: |
Hey; Kenneth E.; (Mercer
Island, WA) ; Kloster; Bryce M.; (Snoqualmie,
WA) |
Correspondence
Address: |
DAVIS WRIGHT TREMAINE, LLP/Seattle
1201 Third Avenue, Suite 2200
SEATTLE
WA
98101-3045
US
|
Assignee: |
SUNSTREAM CORPORATION
Kent
WA
|
Family ID: |
38523343 |
Appl. No.: |
11/690732 |
Filed: |
March 23, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60784904 |
Mar 23, 2006 |
|
|
|
Current U.S.
Class: |
405/3 |
Current CPC
Class: |
B66C 1/62 20130101; B66F
7/08 20130101; B66F 7/0641 20130101; B63C 3/06 20130101 |
Class at
Publication: |
405/003 |
International
Class: |
B63C 3/06 20060101
B63C003/06 |
Claims
1. A watercraft lift for raising and lowering a watercraft in
water, comprising: a buoyant pontoon; a lifting cradle including at
least one air tank and a support bunk configured to receive and
support the watercraft, the air tank having an internal chamber
configured to receive and release pressurized air, the internal
chamber having sufficient internal volume that when sufficient
pressurized air is received therein the air tank has sufficient
buoyancy to lift the lifting cradle to a raised position with the
watercraft out of the water when positioned on the support bunk and
that when sufficient pressurized air is released from the internal
chamber the air tank loses sufficient buoyancy to sink the lifting
cradle to a lowered position sufficiently submerged to receive and
deploy the watercraft; and at least one pivot arm pivotally
connected to the pontoon and pivotally connected to the lifting
cradle to guide movement of the lifting cradle between the lowered
position and the raised position.
2. The watercraft lift of claim 1 wherein the pontoon includes a
buoyant port pontoon portion and a buoyant starboard pontoon
portion, the port and starboard pontoon portions being spaced apart
sufficient to receive the watercraft therebetween.
3. The watercraft lift of claim 2 further including ballast
positioned at the port pontoon portion and ballast positioned at
the starboard pontoon portion in amounts sufficient to prevent the
watercraft lift from rolling when the watercraft is positioned on
the support bunk with the watercraft lift in the raised position
when all pressurized air is released from the internal chamber the
air tank.
4. The watercraft lift of claim 3 wherein the ballast is removably
attached to the port pontoon portion and the ballast is removably
attached to the starboard pontoon portion.
5. The watercraft lift of claim 3 wherein the port and starboard
pontoon portions are made of a first material and the ballast is
made of a second material, the first material being different than
the second material.
6. The watercraft lift of claim 1 wherein the pontoon includes a
buoyant port pontoon portion having an end portion and a buoyant
starboard pontoon portion having an end portion, the port and
starboard pontoon portions being spaced apart sufficient to receive
the watercraft therebetween, and further includes a buoyant
connection pontoon portion having the end portions of the port and
starboard pontoon portions attached thereto, the combined buoyancy
of the port pontoon portion, the starboard pontoon portion and the
connection pontoon portion being sufficient the support bunk in
sufficient contact with the watercraft to prevent the watercraft
from floating off of the support bunk when the watercraft is
positioned on the support bunk with the watercraft lift in the
raised position when all pressurized air is released from the
internal chamber the air tank.
7. The watercraft lift of claim 1 wherein the pontoon includes a
buoyant port pontoon portion having an end portion and a buoyant
starboard pontoon portion having an end portion, the port and
starboard pontoon portions being spaced apart sufficient to receive
the watercraft therebetween, and further includes a buoyant
connection pontoon portion having the end portions of the port and
starboard pontoon portions attached thereto, the port pontoon
portion, the starboard pontoon portion and the connection pontoon
portion having upper surfaces arranged to provide a floating dock
surface for access to the watercraft from three sides thereof when
positioned on the support bunk.
8. The watercraft lift of claim 1 wherein the pontoon includes a
buoyant port pontoon portion having an end portion and a buoyant
starboard pontoon portion having an end portion, the port and
starboard pontoon portions being spaced apart sufficient to receive
the watercraft therebetween, and further includes buoyant port and
starboard connection pontoon portions, the end portion of the port
pontoon portion being attached to the port connection pontoon
portion and the end portion of the starboard pontoon portion being
attached to the starboard connection pontoon portion, and the port
connection pontoon portion and the starboard connection pontoon
portion being removably attached together.
9. The watercraft lift of claim 1 further including a lock operable
to lock the pivot arm relative to the pontoon when the lifting
cradle is in the raised position to prevent downward movement of
the pivot arm and thereby movement of the lifting cradle to the
lowered position.
10. The watercraft lift of claim 9 wherein the lock includes a
selectively rotatable upright member having an engagement member
attached thereto, the rotatable member being rotatable between a
locked position and an unlocked position, in the locked position
the engagement member being positioned in locking engagement with
the pivot arm to prevent downward movement of the pivot arm and
thereby movement of the lifting cradle to the lowered position, and
in the unlocked position the engagement member being positioned out
of locking engagement with the pivot arm to allow downward movement
of the pivot arm and thereby movement of the lifting cradle to the
lowered position.
11. The watercraft lift of claim 10 wherein the lock includes a
security member which when engaged prevents rotation of the
rotatable member out of the locked position.
12. The watercraft lift of claim 1 wherein the pivot arm has an
upper end portion pivotally connected to the pontoon and a lower
end portion pivotally connected to the air tank of the lifting
cradle using a laterally extending member, the lower end portion of
the pivot arm being connected to an end portion of the member to
provide a pivotal connection between the lower end portion of the
pivot arm and the air tank.
13. The watercraft lift of claim 1 wherein the air tank has a
longitudinally extending integrally molded structural rib
projecting upward, the member extending laterally through the
structural rib.
14. The watercraft lift of claim 1 wherein the at least one pivot
arm includes first and second spaced apart port pivot arms, each
having an upper end portion pivotally connected to the pontoon and
a lower end portion pivotally connected to the lifting cradle, and
wherein the air tank has a longitudinally extending integrally
molded structural rib projecting upward and the lower end portions
of the first and second pivot arms are pivotally connected to the
structural rib.
15. The watercraft lift of claim 14 wherein the support bunk is
attached to the air tank in a manner to provide longitudinal
rigidity to the air tank.
16. The watercraft lift of claim 1 wherein the air tank has a
laterally projecting portion extending outward to under the pontoon
to engage the pontoon upon the lifting cradle reaching the raised
position.
17. A watercraft lift for raising and lowering a watercraft in
water, comprising: a buoyant pontoon having a buoyant port pontoon
portion with an end portion, a buoyant starboard pontoon portion
with an end portion, and a buoyant connection pontoon portion with
the end portions of the port and starboard pontoon portions
attached thereto, the port and starboard pontoon portions being
spaced apart sufficient to receive the watercraft therebetween; a
lifting cradle including an air tank assembly and a support bunk
configured to receive and support the watercraft, the air tank
assembly having at least one internal chamber configured to receive
and release pressurized air, the internal chamber having sufficient
internal volume that when sufficient pressurized air is received
therein the air tank assembly has sufficient buoyancy to lift the
lifting cradle to a raised position with the watercraft out of the
water when positioned on the support bunk and that when sufficient
pressurized air is released from the internal chamber the air tank
assembly loses sufficient buoyancy to sink the lifting cradle to a
lowered position sufficiently submerged to receive and deploy the
watercraft; and at least one port pivot arm pivotally connected to
the port pontoon portion and pivotally connected to the lifting
cradle, and at least one starboard pivot arm pivotally connected to
the starboard pontoon portion and pivotally connected to the
lifting cradle, the port and starboard pivot arms configured to
guide movement of the lifting cradle between the lowered position
and the raised position.
18. The watercraft lift of claim 17 wherein the port and starboard
pivot arms are pivotally connected to the lifting cradle using a
member extending between a port side of the lifting cradle and a
starboard side of the lifting cradle, the port pivot arm being
connected to a port end of the member and the starboard pivot arm
being connected to a starboard end of the member.
19. The watercraft lift of claim 18 wherein the member is a torsion
bar.
20. The watercraft lift of claim 17 wherein the pontoon includes a
buoyant port pontoon portion having an end portion and a buoyant
starboard pontoon portion having an end portion, the port and
starboard pontoon portions being spaced apart sufficient to receive
the watercraft therebetween, and further includes a buoyant
connection pontoon portion having the end portions of the port and
starboard pontoon portions attached thereto, the combined buoyancy
of the port pontoon portion, the starboard pontoon portion and the
connection pontoon portion being sufficient the support bunk in
sufficient contact with the watercraft to prevent the watercraft
from floating off of the support bunk when the watercraft is
positioned on the support bunk with the watercraft lift in the
raised position when all pressurized air is released from the
internal chamber the air tank assembly.
21. The watercraft lift of claim 17 further including a first lock
operable to lock the port pivot arm relative to the port pontoon
portion when the lifting cradle is in the raised position to
prevent downward movement of the port pivot arm and thereby
movement of the lifting cradle to the lowered position, and a
second lock operable to lock the starboard pivot arm relative to
the starboard pontoon portion when the lifting cradle is in the
raised position to prevent downward movement of the starboard pivot
arm and thereby movement of the lifting cradle to the lowered
position.
22. The watercraft lift of claim 21 wherein the first lock includes
a selectively rotatable first rotatable upright member having a
first engagement member attached thereto, the first rotatable
member being rotatable supported by the port pontoon portion and
rotatable between a locked position and an unlocked position, in
the locked position the first engagement member being positioned in
locking engagement with the port pivot arm to prevent downward
movement of the port pivot arm and thereby movement of the lifting
cradle to the lowered position, and in the unlocked position the
engagement member being positioned out of locking engagement with
the port pivot arm to allow downward movement of the port pivot arm
and thereby movement of the lifting cradle to the lowered position,
and a selectively rotatable second rotatable upright member having
a second engagement member attached thereto, the second rotatable
member being rotatable supported by the starboard pontoon portion
and rotatable between a locked position and an unlocked position,
in the locked position the second engagement member being
positioned in locking engagement with the starboard pivot arm to
prevent downward movement of the starboard pivot arm and thereby
movement of the lifting cradle to the lowered position, and in the
unlocked position the engagement member being positioned out of
locking engagement with the starboard pivot arm to allow downward
movement of the starboard pivot arm and thereby movement of the
lifting cradle to the lowered position.
23. The watercraft lift of claim 22 wherein the first lock includes
a first security member which when engaged prevents rotation of the
first rotatable member out of the locked position, and the second
lock includes a second security member when engaged prevents
rotation of the second rotatable member out of the locked
position.
24. The watercraft lift of claim 17 wherein the port and starboard
pivot arms each have an upper end portion and a lower end portion,
the upper end portion of the port pivot arm being pivotally
connected to the port pontoon portion and the lower end portion of
the port pivot arm being pivotally connected to the air tank
assembly of the lifting cradle, and the upper end portion of the
starboard pivot arm being pivotally connected to the starboard
pontoon portion and the lower end portion of the starboard pivot
arm being pivotally connected to the air tank assembly of the
lifting cradle.
25. The watercraft lift of claim 24 further including a member
extending between a port side of the air tank assembly and a
starboard side of the air tank assembly, the lower end portion of
the port pivot arm being connected to a port end of the member and
the lower end portion of the starboard pivot arm being connected to
a starboard end of the member.
26. The watercraft lift of claim 17 wherein the air tank assembly
has a longitudinally extending integrally molded structural rib
projecting upward, the member extending laterally through the
structural rib.
27. The watercraft lift of claim 17 wherein the at least one port
pivot arm includes first and second spaced apart port pivot arms,
each having an upper end portion pivotally connected to the port
pontoon portion and a lower end portion pivotally connected to the
lifting cradle, and the at least one starboard pivot arm includes
first and second spaced apart starboard pivot arms, each having an
upper end portion pivotally connected to the starboard pontoon
portion and a lower end portion pivotally connected to the lifting
cradle, and wherein the air tank assembly has a longitudinally
extending integrally molded structural rib projecting upward and
the lower end portions of the first and second port and starboard
pivot arms are pivotally connected to the structural rib.
28. The watercraft lift of claim 27 wherein the support bunk is
attached to the air tank assembly in a manner to provide
longitudinal rigidity to the air tank assembly.
29. The watercraft lift of claim 17 wherein the air tank has a
laterally projecting portion extending outward to under the pontoon
to engage the pontoon upon the lifting cradle reaching the raised
position.
30. A watercraft lift for raising and lowering a watercraft in
water, comprising: a buoyant pontoon having a buoyant port pontoon
portion with an end portion, a buoyant starboard pontoon portion
with an end portion, and a buoyant connection pontoon portion with
the end portions of the port and starboard pontoon portions
attached thereto, the port and starboard pontoon portions being
spaced apart sufficient to receive the watercraft therebetween; a
lifting cradle with support bunks attached thereto and including a
port internal chamber configured to receive and release pressurized
air, and a starboard internal chamber configured to receive and
release pressurized air, the support bunks being configured to
receive and support the watercraft, the combined port and starboard
internal chambers having sufficient internal volume that when
sufficient pressurized air is received therein the lifting cradle
has sufficient buoyancy to lift the lifting cradle to a raised
position with the watercraft out of the water when positioned on
the support bunks and that when sufficient pressurized air is
released from the port and starboard internal chambers the lifting
cradle loses sufficient buoyancy to sink the lifting cradle to a
lowered position sufficiently submerged to receive and deploy the
watercraft; and at least one port pivot arm having an upper end
portion pivotally connected to the port pontoon portion and a lower
end portion pivotally connected to the lifting cradle, and at least
one starboard pivot arm having an upper end portion pivotally
connected to the starboard pontoon portion and a lower end portion
pivotally connected to the lifting cradle, the port and starboard
pivot arms configured to guide movement of the lifting cradle
between the lowered position and the raised position.
31. The watercraft lift of claim 30 wherein a lifting cradle
includes at least one port air tank defining the port internal
chamber and at least one starboard air tank defining the starboard
internal chamber.
32. The watercraft lift of claim 31 further including a
hydrodynamic brake extending between the port and starboard air
tanks to create additional resistance against movement of the
lifting cradle.
33. The watercraft lift of claim 31 wherein the lower end portion
of the port pivot arm is pivotally connected to the port air tank
of the lifting cradle, and the lower end portion of the starboard
pivot arm is pivotally connected to the starboard air tank of the
lifting cradle.
34. The watercraft lift of claim 33 wherein the lower end portions
of the port and starboard pivot arms are pivotally connected to the
port and starboard air tanks of the lifting cradle using a member
extending between a port side of the port air tank and a starboard
side of the starboard air tank, the lower end portion of the port
pivot arm being connected to a port end of the member and the lower
end portion of the starboard pivot arm being connected to a
starboard end of the member.
35. The watercraft lift of claim 34 wherein the member is a torsion
bar extending through an aperture in the port and starboard air
tanks.
36. The watercraft lift of claim 31 wherein the port air tank has a
laterally projecting portion extending outward to under the port
pontoon portion to engage the port pontoon portion upon the lifting
cradle reaching the raised position, and the starboard air tank has
a laterally projecting portion extending outward to under the
starboard pontoon portion to engage the starboard pontoon portion
upon the lifting cradle reaching the raised position.
37. The watercraft lift of claim 30 further including a port relief
port communicating with the port internal chamber and a starboard
relief port communicating with the starboard internal chamber, the
port and starboard relief ports being arranged to permit the
release of pressurized air in one of the port internal chamber and
the starboard internal chamber based on which is least submerged in
the water.
38. The watercraft lift of claim 37 wherein a lifting cradle
includes at least one port air tank defining the port internal
chamber and at least one starboard air tank defining the starboard
internal chamber, and the port relief port is positioned at a port
side of the port air tank and the starboard relief port is
positioned at a starboard side of the starboard air tank.
39. The watercraft lift of claim 30 further including a
hydrodynamic brake extending between the port and starboard air
tanks to create additional resistance against movement of the
lifting cradle.
40. The watercraft lift of claim 30 for conversion for use with a
slip having port and starboard side members, wherein the upper end
portion of the port pivot arm is removably connected to the port
pontoon portion and pivotally attachable to the port side member of
the slip, and the upper end portion of the starboard pivot arm is
removably connected to the starboard pontoon portion and pivotally
attachable to the starboard side member of the slip.
41. The watercraft lift of claim 30 wherein the port and starboard
pontoon portions are each a rotomolded plastic part.
42. A watercraft lift for raising and lowering a watercraft in
water, comprising: a buoyant pontoon having a buoyant port pontoon
portion with an end portion, a buoyant starboard pontoon portion
with an end portion, and a buoyant connection pontoon portion with
the end portions of the port and starboard pontoon portions
attached thereto, the port and starboard pontoon portions being
spaced apart sufficient to receive the watercraft therebetween; a
lifting cradle including a port air tank with a port support bunk
attached thereto and having an internal chamber configured to
receive and release pressurized air, and a starboard air tank with
a starboard support bunk attached thereto and having an internal
chamber configured to receive and release pressurized air, the port
and starboard support bunks being configured to receive and support
the watercraft, the combined internal chambers of the port and
starboard air tanks having sufficient internal volume that when
sufficient pressurized air is received therein the port and
starboard air tanks have sufficient buoyancy to lift the lifting
cradle to a raised position with the watercraft out of the water
when positioned on the port and starboard support bunks and that
when sufficient pressurized air is released from the internal
chambers of the port and starboard air tanks the air tanks loses
sufficient buoyancy to sink the lifting cradle to a lowered
position sufficiently submerged to receive and deploy the
watercraft; and first and second spaced apart port pivot arms, each
having an upper end portion pivotally connected to the port pontoon
portion and a lower end portion pivotally connected to the lifting
cradle, and first and second spaced apart starboard pivot arms,
each having an upper end portion pivotally connected to the
starboard pontoon portion and a lower end portion pivotally
connected to the lifting cradle, the port and starboard pivot arms
configured to guide movement of the lifting cradle between the
lowered position and the raised position, the first and second port
pivot arms, the port pontoon portion and the lifting cradle being
in a 4-bar linkage arrangement and the first and second starboard
pivot arms, the starboard pontoon portion and the lifting cradle
being in a 4-bar linkage arrangement.
43. The watercraft lift of claim 42 wherein the lower end portions
of the first and second port pivot arms are pivotally connected to
the port air tank of the lifting cradle, and the lower end portions
of the first and second of the starboard pivot arms are pivotally
connected to the starboard air tank of the lifting cradle.
44. The watercraft lift of claim 43 wherein the lower end portions
of the first port pivot arm and the first starboard pivot arm are
pivotally connected to the port and starboard air tanks of the
lifting cradle using a first member extending between a port side
of the port air tank and a starboard side of the starboard air
tank, the lower end portion of the first port pivot arm being
connected to a port end of the first member and the lower end
portion of the first starboard pivot arm being connected to a
starboard end of the first member, and wherein the lower end
portions of the second port pivot arm and the second starboard
pivot arm are pivotally connected to the port and starboard air
tanks of the lifting cradle using a second member extending between
a port side of the port air tank and a starboard side of the
starboard air tank and spaced apart from the first member, the
lower end portion of the second port pivot arm being connected to a
port end of the second member and the lower end portion of the
second starboard pivot arm being connected to a starboard end of
the second member.
45. The watercraft lift of claim 44 wherein the first and second
member are a torsion bars, each extending through an aperture in
the port and starboard air tanks.
46. The watercraft lift of claim 44 wherein the port and starboard
air tanks each have a longitudinally extending integrally molded
structural rib projecting upward, the first member extending
through the structural rib of the port and starboard air tanks, and
the second member extending through the structural rib of the port
and starboard air tanks.
47. The watercraft lift of claim 43 wherein the port and starboard
air tanks each have a longitudinally extending integrally molded
structural rib projecting upward, and the lower end portions of the
first and second port pivot arms are pivotally connected to the
structural rib of the port air tank and the lower end portions of
the first and second starboard pivot arms are pivotally connected
to the structural rib of the starboard air tank.
48. The watercraft lift of claim 47 wherein the port support bunk
is attached to the port air tank in a manner to provide
longitudinal rigidity to the port air tank, and the starboard
support bunk is attached to the starboard air tank in a manner to
provide longitudinal rigidity to the starboard air tank.
49. The watercraft lift of claim 42 further including a port relief
port communicating with the interior chamber of the port air tank
and a starboard relief port communicating with the interior chamber
of the starboard air tank, the port and starboard relief ports
being arranged to permit the release of pressurized air in the
interior chamber of the one of the port and starboard air tanks
that is least submerged in the water.
50. The watercraft lift of claim 49 wherein the port relief port is
positioned at the port side of the port air tank and the starboard
relief port is positioned at the starboard side of the starboard
air tank.
51. The watercraft lift of claim 42 further including a first lock
operable to lock one of the first and second port pivot arms
relative to the port pontoon portion when the lifting cradle is in
the raised position to prevent downward movement of the one port
pivot arm and thereby movement of the lifting cradle to the lowered
position, and a second lock operable to lock one of the first and
second starboard pivot arms relative to the starboard pontoon
portion when the lifting cradle is in the raised position to
prevent downward movement of the one starboard pivot arm and
thereby movement of the lifting cradle to the lowered position.
52. The watercraft lift of claim 51 wherein the first lock includes
a selectively rotatable first rotatable upright member having a
first engagement member attached thereto, the first rotatable
member being rotatable supported by the port pontoon portion and
rotatable between a locked position and an unlocked position, in
the locked position the first engagement member being positioned in
locking engagement with the one port pivot arm to prevent downward
movement of the one port pivot arm and thereby movement of the
lifting cradle to the lowered position, and in the unlocked
position the engagement member being positioned out of locking
engagement with the one port pivot arm to allow downward movement
of the one port pivot arm and thereby movement of the lifting
cradle to the lowered position, and a selectively rotatable second
rotatable upright member having a second engagement member attached
thereto, the second rotatable member being rotatable supported by
the starboard pontoon portion and rotatable between a locked
position and an unlocked position, in the locked position the
second engagement member being positioned in locking engagement
with the one starboard pivot arm to prevent downward movement of
the one starboard pivot arm and thereby movement of the lifting
cradle to the lowered position, and in the unlocked position the
engagement member being positioned out of locking engagement with
the one starboard pivot arm to allow downward movement of the one
starboard pivot arm and thereby movement of the lifting cradle to
the lowered position.
53. The watercraft lift of claim 52 wherein the first lock includes
a first security member which when engaged prevents rotation of the
first rotatable member out of the locked position, and the second
lock includes a second security member when engaged prevents
rotation of the second rotatable member out of the locked
position.
54. A watercraft lift for raising and lowering a watercraft in
water, attachable to a slip having a port side and a starboard
side, the watercraft lift comprising: a lifting cradle including a
port air tank with a port support bunk attached thereto and having
an internal chamber configured to receive and release pressurized
air, and a starboard air tank with a starboard support bunk
attached thereto and having an internal chamber configured to
receive and release pressurized air, the port and starboard support
bunks being configured to receive and support the watercraft, the
combined internal chambers of the port and starboard air tanks
having sufficient internal volume that when sufficient pressurized
air is received therein the port and starboard air tanks have
sufficient buoyancy to lift the lifting cradle to a raised position
with the watercraft out of the water when positioned on the port
and starboard support bunks and that when sufficient pressurized
air is released from the internal chambers of the port and
starboard air tanks the air tanks loses sufficient buoyancy to sink
the lifting cradle to a lowered position sufficiently submerged to
receive and deploy the watercraft; first and second spaced apart
port pivot arms, each having an upper end portion pivotally
connectable to the port side of the slip and a lower end portion
pivotally connected to the lifting cradle, and first and second
spaced apart starboard pivot arms, each having an upper end portion
pivotally connectable to the starboard side of the slip and a lower
end portion pivotally connected to the lifting cradle, the port and
starboard pivot arms configured to guide movement of the lifting
cradle between the lowered position and the raised position, the
first and second port pivot arms, the port side of the slip and the
lifting cradle forming a 4-bar linkage arrangement and the first
and second starboard pivot arms, the starboard side of the slip and
the lifting cradle forming a 4-bar linkage arrangement; and a first
lock operable to lock one of the first and second port pivot arms
relative to the port side of the slip when the lifting cradle is in
the raised position to prevent downward movement of the one port
pivot arm and thereby movement of the lifting cradle to the lowered
position, and a second lock operable to lock one of the first and
second starboard pivot arms relative to the starboard side of the
slip when the lifting cradle is in the raised position to prevent
downward movement of the one starboard pivot arm and thereby
movement of the lifting cradle to the lowered position.
55. The watercraft lift of claim 54 wherein the first lock includes
a selectively rotatable first rotatable upright member having a
first engagement member attached thereto, the first rotatable
member being rotatable supported by the port side of the slip and
rotatable between a locked position and an unlocked position, in
the locked position the first engagement member being positioned in
locking engagement with the one port pivot arm to prevent downward
movement of the one port pivot arm and thereby movement of the
lifting cradle to the lowered position, and in the unlocked
position the engagement member being positioned out of locking
engagement with the one port pivot arm to allow downward movement
of the one port pivot arm and thereby movement of the lifting
cradle to the lowered position, and a selectively rotatable second
rotatable upright member having a second engagement member attached
thereto, the second rotatable member being rotatable supported by
the starboard side of the slip and rotatable between a locked
position and an unlocked position, in the locked position the
second engagement member being positioned in locking engagement
with the one starboard pivot arm to prevent downward movement of
the one starboard pivot arm and thereby movement of the lifting
cradle to the lowered position, and in the unlocked position the
engagement member being positioned out of locking engagement with
the one starboard pivot arm to allow downward movement of the one
starboard pivot arm and thereby movement of the lifting cradle to
the lowered position.
56. The watercraft lift of claim 55 wherein the first lock includes
a first security member which when engaged prevents rotation of the
first rotatable member out of the locked position, and the second
lock includes a second security member when engaged prevents
rotation of the second rotatable member out of the locked
position.
57. A watercraft lift for raising and lowering a watercraft in
water, attachable to a slip having a port side and a starboard
side, the watercraft lift comprising: a lifting cradle including a
port air tank with a port support bunk attached thereto and having
an internal chamber configured to receive and release pressurized
air, and a starboard air tank with a starboard support bunk
attached thereto and having an internal chamber configured to
receive and release pressurized air, the port and starboard support
bunks being configured to receive and support the watercraft, the
combined internal chambers of the port and starboard air tanks
having sufficient internal volume that when sufficient pressurized
air is received therein the port and starboard air tanks have
sufficient buoyancy to lift the lifting cradle to a raised position
with the watercraft out of the water when positioned on the port
and starboard support bunks and that when sufficient pressurized
air is released from the internal chambers of the port and
starboard air tanks the air tanks loses sufficient buoyancy to sink
the lifting cradle to a lowered position sufficiently submerged to
receive and deploy the watercraft; first and second spaced apart
port pivot arms, each having an upper end portion pivotally
connectable to the port side of the slip and a lower end portion
pivotally connected to the lifting cradle, and first and second
spaced apart starboard pivot arms, each having an upper end portion
pivotally connectable to the starboard side of the slip and a lower
end portion pivotally connected to the lifting cradle, the port and
starboard pivot arms configured to guide movement of the lifting
cradle between the lowered position and the raised position, the
first and second port pivot arms, the port side of the slip and the
lifting cradle forming a 4-bar linkage arrangement and the first
and second starboard pivot arms, the starboard side of the slip and
the lifting cradle forming a 4-bar linkage arrangement; and a first
member attached to port and starboard air tanks and extending
between a port side of the port air tank and a starboard side of
the starboard air tank, the lower end portions of the first port
pivot arm and the first starboard pivot arm being pivotally
connected to the port and starboard air tanks of the lifting cradle
using the first member, the lower end portion of the first port
pivot arm being connected to a port end of the first member and the
lower end portion of the first starboard pivot arm being connected
to a starboard end of the first member; and a second member
attached to port and starboard air tanks and extending between a
port side of the port air tank and a starboard side of the
starboard air tank and spaced apart from the first member, the
lower end portions of the second port pivot arm and the second
starboard pivot arm being pivotally connected to the port and
starboard air tanks of the lifting cradle using the second member,
the lower end portion of the second port pivot arm being connected
to a port end of the second member and the lower end portion of the
second starboard pivot arm being connected to a starboard end of
the second member.
58. The watercraft lift of claim 57 wherein the first and second
member are a torsion bars, each extending through an aperture in
the port and starboard air tanks.
59. The watercraft lift of claim 57 wherein the port and starboard
air tanks each have a longitudinally extending integrally molded
structural rib projecting upward, the first member extending
through the structural rib of the port and starboard air tanks, and
the second member extending through the structural rib of the port
and starboard air tanks.
60. The watercraft lift of claim 57 wherein the port support bunk
is attached to the port air tank in a manner to provide
longitudinal rigidity to the port air tank, and the starboard
support bunk is attached to the starboard air tank in a manner to
provide longitudinal rigidity to the starboard air tank.
61. A watercraft lift for raising and lowering a watercraft in
water, attachable to a slip having a port side and a starboard
side, the watercraft lift comprising: a lifting cradle including a
port air tank with a port support bunk attached thereto and having
an internal chamber configured to receive and release pressurized
air, and a starboard air tank with a starboard support bunk
attached thereto and having an internal chamber configured to
receive and release pressurized air, the port and starboard support
bunks being configured to receive and support the watercraft, the
combined internal chambers of the port and starboard air tanks
having sufficient internal volume that when sufficient pressurized
air is received therein the port and starboard air tanks have
sufficient buoyancy to lift the lifting cradle to a raised position
with the watercraft out of the water when positioned on the port
and starboard support bunks and that when sufficient pressurized
air is released from the internal chambers of the port and
starboard air tanks the air tanks loses sufficient buoyancy to sink
the lifting cradle to a lowered position sufficiently submerged to
receive and deploy the watercraft; first and second spaced apart
port pivot arms, each having an upper end portion pivotally
connectable to the port side of the slip and a lower end portion
pivotally connected to the lifting cradle, and first and second
spaced apart starboard pivot arms, each having an upper end portion
pivotally connectable to the starboard side of the slip and a lower
end portion pivotally connected to the lifting cradle, the port and
starboard pivot arms configured to guide movement of the lifting
cradle between the lowered position and the raised position, the
first and second port pivot arms, the port side of the slip and the
lifting cradle forming a 4-bar linkage arrangement and the first
and second starboard pivot arms, the starboard side of the slip and
the lifting cradle forming a 4-bar linkage arrangement; and a
hydrodynamic brake extending between the port and starboard air
tanks to create additional resistance against movement of the
lifting cradle.
Description
FIELD OF THE INVENTION
[0001] The invention generally relates to an apparatus and method
for lifting watercraft out of the water.
DESCRIPTION OF THE RELATED ART
[0002] The use of watercraft lifting devices is well known.
Out-of-water storage prevents damage resulting from boat contact
with docks, other craft or floating debris. It reduces the
possibility of the boat breaking free from its moorage and floating
adrift or running aground. Out-of-water storage also lessens boat
damage associated with long-term exposure to water and water-based
pollutants and the attachment of barnacles or other marine growth
to the boat's hull. Once a boat is lifted it can be maintained in
its position for extended periods of time, relieving the user of
maintenance concerns. In certain situations where the water
fluctuation is high, water depth is too deep, or permanent mounting
is undesired, floating watercraft lifting devices are used. A
number of floating lift designs are currently known that provide
this basic function.
[0003] U.S. Pat. No. 5,002,000 to Rutter uses air filled pontoons
as a lifting device combined with a complicated array of air inlet
and outlet valves to control lateral stability while lifting. With
this device the rear portion of the pontoons are lowered more than
the forward portion of the pontoons to allow ingress and egress of
the boat. This device, however, is limited in that the watercraft
will not be raised or lowered in a horizontal position which is
undesirable to many users.
[0004] U.S. Pat. No. 5,860,379 to Moody comprises of an inflatable
fabric air chamber as the lifting device. While this device raises
the boat out of the water, it has many disadvantages including a
complicated rope tying configuration for stabilizing,
non-horizontal lifting by raising the bow of the watercraft before
the stern, and incompatibility with all boats by only fitting boats
with outboard and inboard/outboard motors.
[0005] U.S. Pat. No. 6,848,380 to Sainz is a floating watercraft
lift that addresses the fore and aft stability issues and
non-horizontal lifting with the boatlifts described in Moody and
Rutter by using air chambers with an arcuate longitudinal top
surface and a base side that is flat. While addressing these
stability issues, the lift suffers from a number of disadvantages
including the lack of a means for keeping the lift stable if air
pressure is lost in one or all pontoon chambers, the ability to fit
in a narrow boat slip, and the lack of reserve buoyancy to keep the
device from sinking if all air pressure is lost.
[0006] Two known devices, one from Hydrohoist International, Inc.
and the other from Shoremaster, address the fore and aft stability
and non-horizontal lifting described in Moody and Rutter in another
fashion. Both devices are air displacement watercraft lifts using
stabilizing brackets fixed to a dock or slip to maintain horizontal
lifting of the watercraft. These fixed stabilizing brackets are
undesirable for marina operations and limit the ease of portability
for these lifts. A similar method for stabilizing a boat lift is
described in U.S. Pat. No. 4,750,444 to Lemvig, wherein the lift is
comprised of a platform with a deck and lifting skirt and link arms
connecting the platform to a quay. Air is supplied to the lifting
skirt to raise a watercraft while the link arms attached to the
quay stabilize the platform. Similar to the Hydrohoist and
Shoremaster devices, the device of Lemvig requires link arms fixed
to a quay to stabilize the lift limiting the portability of the
lift.
[0007] Hydrohoist International, Inc. and Airberth address
portability issues with free floating side tie lifts. These lifts
use air tanks rigidly attached to side floatation to control
lifting and stability. While allowing for portability and side tie
capabilities, these lifts do not raise the watercraft in a
horizontal position and have similar disadvantages to Rutter and
Moody.
[0008] In addition to the above stated short comings, the floating
watercraft lifts of Rutter, Moody, Sainz, Hydrohoist, Shoremaster
and Air Berth may inadvertently lower the watercraft into the water
if air pressure is not maintained in one or all air chambers. In
this case the watercraft will become susceptible to the damaging
elements described above.
[0009] Another difficulty facing floating watercraft lift
manufacturers is the multitude of mounting scenarios. To meet the
lift mounting requirements, the manufacturers offer different lifts
for slip, side-tie and forward mounting applications. By offering
three different lifts the manufacturer and dealer must increase
inventory levels and warehouse storage space.
[0010] Accordingly, there is a need in the art for a floating
watercraft lift that addresses all of the following issues of
horizontal lifting of the watercraft with a desirable stabilizing
feature, compatibility with all boat drive configurations,
stability if air pressure is lost in one or all air chambers, the
ability to fit in narrow boat slips, portability for ease of
installation and removal, damage tolerance to keep the watercraft
out of the water if one or all of the air chambers lose air
pressure, and convertibility to most floating watercraft lift
mounting scenarios.
SUMMARY OF THE INVENTION
[0011] A watercraft lift for raising and lowering a watercraft in
water. The watercraft lift includes a buoyant pontoon, a lifting
cradle and at least one pivot arm. The lifting cradle includes at
least one air tank and a support bunk configured to receive and
support the watercraft. The air tank has an internal chamber
configured to receive and release pressurized air. The internal
chamber has sufficient internal volume that when sufficient
pressurized air is received therein the air tank has sufficient
buoyancy to lift the lifting cradle to a raised position with the
watercraft out of the water when positioned on the support bunk and
that when sufficient pressurized air is released from the internal
chamber the air tank loses sufficient buoyancy to sink the lifting
cradle to a lowered position sufficiently submerged to receive and
deploy the watercraft. The pivot arm is pivotally connected to the
pontoon and pivotally connected to the lifting cradle to guide
movement of the lifting cradle between the lowered position and the
raised position.
[0012] In one embodiment the pontoon includes a buoyant port
pontoon portion and a buoyant starboard pontoon portion. The port
and starboard pontoon portions are spaced apart sufficient to
receive the watercraft therebetween.
[0013] The watercraft lift may further include ballast removably
attached to the port pontoon portion and ballast removably attached
to the starboard pontoon portion in amounts sufficient to prevent
the watercraft lift from rolling when the watercraft is positioned
on the support bunk with the watercraft lift in the raised position
when all pressurized air is released from the internal chamber the
air tank. The port and starboard pontoon portions are made of a
first material and the ballast is made of a second material, the
first material being different than the second material.
[0014] The pontoon includes a buoyant port pontoon portion having
an end portion and a buoyant starboard pontoon portion having an
end portion. The port and starboard pontoon portions are spaced
apart sufficient to receive the watercraft therebetween. The
pontoon further includes a buoyant connection pontoon portion
having the end portions of the port and starboard pontoon portions
attached thereto. The combined buoyancy of the port pontoon
portion, the starboard pontoon portion and the connection pontoon
portion is sufficient hold the watercraft out of the water when the
watercraft is positioned on the support bunk with the watercraft
lift in the raised position when all pressurized air is released
from the internal chamber the air tank.
[0015] The port pontoon portion, the starboard pontoon portion and
the connection pontoon portion have upper surfaces arranged to
provide a floating dock surface for access to the watercraft from
three sides thereof when positioned on the support bunk.
[0016] The connection pontoon portion has buoyant port and
starboard connection pontoon portions, with the end portion of the
port pontoon portion attached to the port connection pontoon
portion and the end portion of the starboard pontoon portion
attached to the starboard connection pontoon portion. The port
connection pontoon portion and the starboard connection pontoon
portion are removably attached together.
[0017] The watercraft lift may further include a lock operable to
lock the pivot arm relative to the pontoon when the lifting cradle
is in the raised position to prevent downward movement of the pivot
arm and thereby movement of the lifting cradle to the lowered
position. The lock includes a selectively rotatable upright member
having an engagement member attached thereto, the rotatable member
being rotatable between a locked position and an unlocked position.
In the locked position the engagement member is positioned in
locking engagement with the pivot arm to prevent downward movement
of the pivot arm and thereby movement of the lifting cradle to the
lowered position. In the unlocked position the engagement member is
positioned out of locking engagement with the pivot arm to allow
downward movement of the pivot arm and thereby movement of the
lifting cradle to the lowered position. The lock may include a
security member which when engaged prevents rotation of the
rotatable member out of the locked position.
[0018] Other features and advantages of the invention will become
apparent from the following detailed description, taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0019] The foregoing aspects and many of the attendant advantages
of this invention will become more readily appreciated as the same
becomes better understood by reference to the following detailed
description, when taken in conjunction with the accompanying
drawings, which are schematic, and not to scale, wherein:
[0020] FIG. 1 is an isometric view of a watercraft lift according
to the present invention in a lowered position.
[0021] FIG. 2 is an isometric view of the watercraft lift of FIG. 1
in a position between a raised position and the lowered
position.
[0022] FIG. 3 is an isometric view of the watercraft lift of FIG. 1
in the raised position.
[0023] FIG. 4 is an enlarged, isometric view of an air tank of the
watercraft lift of FIG. 1.
[0024] FIG. 5 is an enlarged, isometric view of a lifting cradle of
the watercraft lift of FIG. 1.
[0025] FIG. 6 is an isometric view of ballasted floating pontoons
of the watercraft lift of FIG. 1.
[0026] FIG. 7 is a side view of a swing arm of the watercraft lift
of FIG. 1.
[0027] FIG. 8 is an front view of the swing arm and torsion bar
assembly of the watercraft lift of FIG. 1.
[0028] FIG. 9 is a sectional side elevational view of the
watercraft lift of FIG. 1 showing a 4-bar linkage arrangement of
the swing arms.
[0029] FIG. 10 is an enlarged, isometric view of a lock mechanism
of the watercraft lift of FIG. 1.
[0030] FIG. 11 is a rear elevational view of the watercraft lift of
FIG. 1 in the lowered position with the watercraft in the
load/unload position.
[0031] FIG. 12 is a rear elevational view of the watercraft lift of
FIG. 1 in the raised position with the watercraft in the stored
position.
[0032] FIG. 13 is a top plan view of the watercraft lift of FIG. 1
in a 4-point tie configuration in a slip.
[0033] FIG. 14 is a top plan view of the watercraft lift of FIG. 1
in a forward mounting tie configuration.
[0034] FIG. 15 is a top plan view of the watercraft lift of FIG. 1
in a side tie configuration.
[0035] FIG. 16 is an isometric view of the watercraft lift of FIG.
1 with a canopy mounted to the floating pontoons.
[0036] FIG. 17 is an isometric view of the watercraft lift of FIG.
1 with a hydrodynamic element to control the acceleration and
velocity of raising and lowering the lifting cradle.
[0037] FIG. 18 is an isometric view of multiple watercraft lifts of
the type shown in FIG. 1 mounted side by side.
[0038] FIG. 19 is an isometric view of the watercraft lift of FIG.
1 with air hoses routed through a center of the watercraft
lift.
[0039] FIG. 20 is an isometric view of the watercraft lift of FIG.
1 with the floating pontoons removed and swing arms pivotally
attached to a slip.
DETAILED DESCRIPTION OF THE INVENTION
[0040] This section illustrates aspects of the invention, and
points out certain preferred embodiments of these aspects. This
section is not intended to be exhaustive, but rather to inform and
teach the person of skill in the art who will come to appreciate
more fully other aspects, equivalents, and possibilities presented
by invention, and hence the scope of the invention is set forth in
the claims, which alone limit its scope.
[0041] Several embodiments of the invention are set forth in the
following description: FIGS. 1 through 20 provide a thorough
understanding of such embodiments. One skilled in the art will
understand that the present invention may be practiced without
several of the details described herein. In the following
description of the embodiments, it is understood that a watercraft
includes any vehicle that is at least partially waterborne, which
includes boats and similar vessels, but may also include amphibious
vehicles including various amphibious automobiles or aircraft.
Moreover, in the description that follows, it is understood that
the figures related to the various embodiments are not to be
interpreted as conveying any specific or relative physical
dimension, and that specific or relative dimensions related to the
various embodiments, if stated, are not be considered limiting
unless future claims state otherwise.
[0042] An isometric view of a watercraft lift 10 in a fully lowered
position is shown in FIG. 1. The watercraft lift 10, having a port
side A and a starboard side B, includes a lifting cradle 50
comprising two air tanks 40 each having a lifting bunk 51, and a
pair of port and starboard floating pontoons 60 with the lifting
cradle positioned between the laterally spaced apart rearward
portions of the floating pontoons. Fore and aft pivotal connectors
80 pivotally connect the lifting cradle 50 to the floating pontoons
60. Each pivotal connector 80 includes a torsion bar 81 extending
through the lifting cradle 50 and two swing arm 70 attached to the
torsion bar, one on each side of the lifting cradle. One swing arm
70 of the pivotal connector 80 is pivotally connected to the port
floating pontoon 60, and the other swing arm of the pivotal
connector is pivotally connected to the starboard floating pontoon
60. As best seen in FIG. 9 for the port side A, the swing arms 70
of the fore and aft pivotal connectors 80 are pivotally attached at
points 91 and 92 on the port floating pontoon 60 and are also
pivotally attached to the lifting cradle 50 at points 43 and 44.
The lower ends of the swing arms 70 rotate forward and upwardly
towards the forward floats 61 as air volume is increased within the
air tanks 40. The lifting bunks 51 provide support to the hull of a
watercraft 111 when in engagement therewith as shown in FIG.
12.
[0043] Again referring to FIG. 1, each floating pontoon 60 has a
forward float 61, three side floats 62, side ballasts 63 and
forward ballast 64. As will be described below, these floats are
connected together to form a dock like structure for access to the
watercraft 111 using the watercraft lift 10 from three sides.
[0044] FIG. 2 shows the watercraft lift 10 in a partially raised
position from the lowered position shown in FIG. 1 which results
from the pumping of air into the air tanks 40 of the lifting cradle
50 and the resulting purging of the water therein. As the air
volume is increased within the air tanks 40, the lifting cradle 50
increases in buoyancy and rises to engage the lifting bunks 51 with
the hull of the watercraft 111 thereabove. Thereafter, the lifting
cradle 50 carries the watercraft on the lifting bunks 51 upward
with the lifting cradle. If the watercraft lift 10 starts to list
to the port side A, the side floats 62 on the port side A and the
side ballast 63 on the starboard side B will provide the righting
moment to stabilize the watercraft lift and prevent the watercraft
111 from rolling off of the lifting bunks 51. In the same manner,
if the watercraft lift 10 lists to starboard side B, the side
floats 62 on the starboard side B and the side ballast 63 on the
port side A will provide the righting moment to stabilize the
watercraft lift and prevent the watercraft 111 from rolling off of
the lifting bunks 51. This provides increase laterally stability
for the watercraft lift 10.
[0045] FIG. 3 shows the watercraft lift 10 in a fully raised
position with the lifting cradle 50 in a raised position sufficient
to hold the watercraft 111 out of the water as shown in FIG. 12.
The air volume in the air tanks 40 is selected to be sufficient
that in combination with the buoyancy of the floating pontoons 60
the watercraft 111 will be held in a raised position above the
water (see FIG. 12). It is noted that the floating pontoons 60 stay
floating in the water throughout the operation of the watercraft
lift 10, and that when the lifting cradle 50 is in the fully raised
position of FIG. 3 the lifting cradle and the floating pontoons are
spaced apart at a first distance, and when the lifting cradle is in
the fully lowered position of FIG. 1 the lifting cradle and the
floating pontoons are spaced apart at a second distance with the
second distance being greater than the first distance.
[0046] FIG. 4 shows an isometric view of the air tank 40 of the
watercraft lift 10. The air tank 40 serves as the lower structural
bar of a 4-bar linkage 90. The air tank 40 is made from a hollow
rotationally molded structural plastic shell with a longitudinally
extending, upwardly projecting, integrally formed strengthening rib
41, laterally extending, upwardly projecting, integrally formed
forward and rearward bunk towers 48, and longitudinally extending,
upwardly projecting, integrally formed gussets 47. The rib 41
provides stiffness and rigidity, and the bunk towers 48 and gussets
47 distribute the load over the entire air tank without the need
for an external structure to provide the main load support and also
would increase the height of the lifting cradle. The air tank 40
further has a water inlet and outlet port 45, an air inlet and
outlet port 42, an adjustable relief port 46 and horizontally
adjustable pivot points 43 and 44 using the adjustment brackets
49.
[0047] As shown in FIG. 5, the lifting cradle 50 has two air tanks
40, each with one lifting bunks 51 mounted to a top side thereof
atop the bunk towers 48. The lifting bunks 51 is rigidly attach to
the air tanks 40 on bunk towers 48 thus adding bending stiffness to
the air tank of the lifting cradle 50. The lifting cradle 50 lifts
the watercraft 111 by introducing air through the air inlet and
outlet port 42, and thereby evacuating water within the air tank 40
through water inlet and outlet port 45, thus increasing the
buoyancy of the air tank. If watercraft lift 10 lists, air will
escape through the adjustable relief port 46 of the air tank 40
which is the least submerged, thus reducing its buoyancy and
preventing the watercraft lift from rolling. The relief port 46
comprises a column of through-holes in the wall of the air tank,
each to be at a different height relative to the water line. The
relief port 46 is adjustable in that based on the size of the
watercraft to be supported by the lifting cradle 50, plugs can be
used to close selected ones of the through-holes and thereby
control the ones which are operable. The adjustable relief port 46
is provided on the laterally outward side of each of the air tanks
40. When it is desired to lower the lifting cradle 50 to lower the
watercraft 111 supported, the air within the air tanks is released
through the air inlet and outlet port 42, and thereby allowing
water to enter within the air tank 40 through water inlet and
outlet port 45, thus decreasing the buoyancy of the air tank.
[0048] The air tanks 40 each include a longitudinally extending,
laterally outward projecting lower portion 40A. As best seen in
FIG. 12, the lifting cradle 50 is sized so that when positioned
between the floating pontoons 60, the laterally outward projecting
lower portion 40A of the port air tank 40 when the lifting cradle
50 is in the fully raised position extends laterally outward to
under the lower side of the port floating pontoon and engages the
lower side of the port floating pontoon, and the laterally outward
projecting lower portion 40A of the starboard air tank 40 when the
lifting cradle 50 is in the fully raised position extends laterally
outward to under the lower side of the starboard floating pontoon
and engages the lower side of the starboard floating pontoon. With
this arrangement, the floating pontoons 60 serve as stops for the
upward movement of the lifting cradle 50. Further, the contact of
the laterally outward projecting lower portions 40A of the air
tanks 40 with the lower sides of the floating pontoons 60 provides
the watercraft lift 10 with increased rigidity and stability when
the lifting cradle 50 is in the fully raised position shown in FIG.
12.
[0049] FIG. 6 shows the port and starboard floating pontoons 60
without the lifting cradle 50. Each of the floating pontoons 60
includes three side floats 62 and one forward float 61. The side
floats 62 and the forward float 61 of each floating pontoon 60 are
mechanically link together with a tube 67 to which each is attached
at its laterally inward side. The side ballast 63 is removably
attached to a top side of the side floats 62, and the forward
ballast 64 is removably attached to a top side of the forward
floats 61. The side ballast 63 includes heavy concrete tiles that
provide ballast for the watercraft lift 10 as described above. The
forward ballast 64 helps keep the watercraft lift 10 in an
acceptable fore-aft attitude in the event air pressure within the
air chambers 40 is lost or compromised and the floating pontoons 60
must support the watercraft 111 when the watercraft lift 10 is in a
locked raised position which will be described below. The forward
ballast 64 is shown as a heavy grate that covers a through opening
in the forward float 61. The through opening reduces the light
blocked by the watercraft lift 10.
[0050] The side floats 62 and the forward floats 61 are constructed
of a sealed rotationally molded plastic shell with a foam filled or
an air filled inner core for buoyancy. The buoyancy is selected to
be sufficient to keep the watercraft 111 supported high enough
above the water and in sufficient frictional contact with the
lifting bunks 51 to keep the watercraft from floating off and away
from the lifting cradle 50 when the lifting cradle is in the locked
raised position even if all air pressure in the air tanks 40 is
lost and the air tanks provide no buoyancy. The forward floats 61
are shaped on an inward side to accept and position the bow of the
watercraft 111 must like a boat slip, and are designed to be used
as mirrored parts as shown in FIG. 6.
[0051] The port and starboard floating pontoons 60 are attached
together at a connection location 69 with a mechanical connection
68 which connects together the front floats 61 of the two floating
pontoons. The floating pontoons 60 can be split at the connection
location 69 and a spacer float (not shown) can be added
therebetween to increase the distance between the side floats 62 of
the floating pontoons to accept a boat with a wider beam.
[0052] FIG. 7 shows the swing arms 70 as having an upper pivot
point 71 at an upper end thereof and a lower pivot point 72 at the
opposite lower end thereof. The upper end of the swing arm 70 is
pivotally attached to the floating pontoon 60 for pivotal movement
relative thereto about the upper pivot point 71, and the lower end
of the swing arm is rigidly attached to one end of the torsion bar
81 of the pivotal connector 80 for pivotal movement relative to the
lifting cradle 50 about the lower pivot point 72. The pivotal
connector 80 is shown in FIG. 8 with one of the swing arms 70
rigidly attached to each of the two opposite ends of the torsion
bar 81. As shown in FIG. 7, the swing arm 70 has a substantially
straight lower end portion with a shorter upper end portion at an
angle relative to the lower end portion such that when the swing
arm is rotated forward with the lower end shape aligned with a
horizontal axis 73 with the upper pivot point 71 on the horizontal
axis, the lower end portion of the of the swing arm and the lower
pivot point 72 are offsets below horizontal axis.
[0053] In FIG. 9, the 4-bar linkage 90 on the port side of the
watercraft lift 10 is shown as the tube 67 of the port floating
pontoon 60 being a first upper bar, the air tank 40 of the lifting
cradle 50 being a second lower bar, and the forward and rearward
swing arms 70 of the two pivotal connectors 80 being the third and
fourth bars. Of course, there is a similar 4-bar linkage 90 formed
at each of the port and starboard floating pontoons 60. The upper
pivot points 71 of the swing arms 70 are pivotally attached to the
tube 67 of floating pontoons 60 at points 91 and 92, and the lower
pivot points 72 of the swing arms are pivotally attached at points
93 and 94 to the pivots 43 and 44 of air tanks 40 by the torsion
bars 81. The use of the 4-bar linkage 90 provides the watercraft
lift 10 with a level lift and lowering of the watercraft 111 by the
lifting cradle 50.
[0054] The adjustment brackets 49 (best seen if FIG. 4) each have
an aperture through which the end portion of the torsion bar 81
extends and in which it is rotatably mounted. The adjustment
brackets 49 are positionable during manufacture of the watercraft
lift 10 along the rib 41 of the air tank 40 to achieve the desired
longitudinal separation between the torsion bars 81 of the fore and
aft pivotal connectors 80 even if the molding process used for the
air tank produces a variation in the size of the air tank from one
to the other.
[0055] A lock mechanism 100 is shown in FIG. 10 as being associated
with one of the swing arms 70 pivotally attached to the port
floating pontoon 60 and with one of the swing arms pivotally
attached to the starboard floating pontoon. The lock mechanism 100
is selectively rotatable about a vertical axis to engage the
adjacent swing arm 70 and limit the downward movement thereof, and
thus locking the floating pontoon 60 to the lifting cradle 50 with
the lifting cradle in the raised position. The lock mechanism 100
includes an engagement lever 104 at its top end, a lock shaft 101
to which the engagement lever is attached, a lock plate 103 for
lock position indication, a load holding shoulder 105, and an
engagement foot 102. The lock mechanism 100 is mounted through one
of the side floats 62 and is bolted to the tube 67 using a clamp
106 which allows the lock shaft 101 to rotate therein relative to
the side float. When the engagement lever 104 is rotated into a
locked position D, the lock shaft 101 is rotate about the vertical
axis to rotate the engagement foot 102 into position below the
swing arm 70, thus limiting the downward rotational travel of the
swing arm toward the lowered position shown in FIG. 1. When swing
arm 70 rotates downward sufficient to engage the engagement foot
102, the load holding shoulder 105 transfers the load placed
thereon by the swing arm and the lifting cradle 50 to which it is
connected, to the side float 62 of the floating pontoon 60 through
the clamp 106 and the tube 67. As discussed above, the ability to
lock and hold the lifting cradle 50 in the raised position and
providing the forward floats 61 and the side floats 62 of the
floating pontoons 60 with sufficient buoyancy to support the full
weight of the watercraft 111 and keep the watercraft above the
water even should the entire air pressure in the air tanks 40 be
lost, provides the watercraft lift 10 with a significant safety
feature in the event of a failure that results in air pressure loss
in the air tanks.
[0056] When engagement lever 104 is rotated along path E to an
unlocked position C, the engagement foot 102 rotates to a position
where it will not engage swing arm 70 and hence not limit downward
rotation of the swing arm toward the lowered position shown in FIG.
1 and allow its unimpeded upward movement.
[0057] When the engagement lever 104 is rotated into the locked
position D, the lock mechanism 100 prevents accidental or
unintended lowering of the watercraft 111 into the water. Even
should air pressure be released from the air tanks 40, the locking
mechanism will prevent lowering of the lifting cradle 50. When the
engagement lever 104 is rotated into the locked position D, the
engagement lever 104 may be padlocked to the lock plate 103 or in
alternative embodiments otherwise locked to prevent rotation of the
lock shaft 101 and hence rotation of the engagement foot 102 from
under the swing arm 70. This provides protection against theft of
the watercraft 111 when on the lifting cradle 50 in the raised
position since without being able to rotate the engagement lever to
the unlocked position C, the lifting cradle cannot be lowered to
place the watercraft in the water, thus preventing unauthorized
removal of the watercraft from the watercraft lift 10.
[0058] FIG. 11 shows a rear view of the watercraft lift 10 in the
lowered position with the watercraft 111 in the load/unload
position. The lock mechanism 100 is in the unlocked position C. The
watercraft 111 is shown floating with respect to a waterline 112
and the lifting cradle 50 is submerged below and does not touch the
watercraft 111.
[0059] FIG. 12 shows a rear view of the watercraft lift 10 in the
raised position with the watercraft 111 in the stored position with
the lifting bunks 51 engaging the hull of the watercraft. The
locking mechanism 100 is in the locked position D. The watercraft
111 rests on the lifting bunks 51 which supports it in a position
above the waterline 102.
[0060] The floating pontoons 60 can be tied or attached to a dock,
sea wall or quay at tie points 66. The watercraft lift 10 is shown
in FIG. 13 in a 4-point tie configuration with dock lines 131 tied
to a slip 132 and to the lift tie points 66 on the floating
pontoons 60.
[0061] The watercraft lift 10 is shown in FIG. 14 in a forward
mounting configuration with dock lines 141 tied to a dock 142 and
the front lift tie points 66 on the floating pontoons 60.
[0062] The watercraft lift 10 is shown in FIG. 15 in a side tie
configuration with dock lines 151 tied to a dock 152 and the lift
tie points 66 on the floating pontoons 60.
[0063] The watercraft lift 10 is shown in FIG. 16 with a canopy 161
mounted to floating pontoons 60 using four canopy uprights 162.
[0064] The watercraft lift 10 is shown in FIG. 17 with a
hydrodynamic brake element 171 used to control the acceleration and
velocity of the raising and lowering of the lifting cradle 50. This
reduces hull impact on raising of the lifting cradle 50 to provide
a smooth lift. The hydrodynamic element 171 is removably attached
to the lifting cradle 50 in position between the air tanks 40 and
extends substantially fully between the air tanks. The hydrodynamic
element 102 has a configuration selected to create increased water
resistance to movement of the lifting cradle 50 as it moves upward
and downward beyond the water resistance that would be experience
otherwise. This is accomplished by the hydrodynamic element 102
catching the water and thereby forcing the water to flow over and
around it. The hydrodynamic element 102 configuration provides
water resistance that supplements the natural water resistance
experienced by the lifting cradle 50 to control the acceleration
and velocity of raising and lowering the lifting cradle.
[0065] A plurality of the watercraft lifts 10 are shown in FIG. 18
with the watercraft lifts mounted side-by-side. The front ends of
the forward floats 61 of the floating pontoons 60 have a straight
forward portion 183 that engages a straight side of a dock 181, and
are mechanically connected to the dock. The adjacent outward sides
182 of the floating pontoons 60 of the watercraft lifts 10 are in
engagement and the adjacent floating pontoons are mechanically
connected together. In this arrangement, the watercraft lifts 10
can be used with a simple dock to provide a plurality of boat slips
with floating watercraft lifts and allows the convenient
construction of a marina.
[0066] The watercraft lift 10 is shown in FIG. 19 with a conduit
191 having a length centrally routed between the floating pontoons
60 and air tanks 40. The conduit 191 contains two air hoses. With
this arrangement the conduit 191 and the hoses contained therein
are below the watercraft 111 when on the lifting cradle 50 and
hidden from view. Even when the watercraft 111 is not present, the
conduit 191 provides an uncluttered appearance and reduces the
chance of entanglement of the air hoses with foreign objects. The
conduit 191 is corrugated and has an elastic member arranged to
keep the conduit and hence the hoses out of the water and free from
marine growth. The hoses within the conduit 191 connect to the air
inlet and outlet port 42 of the air tanks 40 to provide pressurized
air to the interior of the air tanks at sufficient pressure to
evacuate the water therein and lift the lifting cradle 50 with the
watercraft 111 thereon to the raised position, and to allow release
of the pressurized air in the air tanks for lowering of the lifting
cradle.
[0067] The watercraft lift 10 is shown in FIG. 20 with the floating
pontoons 60 removed and the swing arms 70 of the pivotal connectors
80 pivotally attached to a slip 201 by their upper pivot points 71
at connection points 202, 203, 204 and 205. This arrangement allows
the watercraft lift 10 to be converted from a self-supported
floating lift to a lift supported by a ground supported slip as
desired.
[0068] It will be appreciated that, although specific embodiments
of the invention have been described herein for purposes of
illustration, various modifications may be made without departing
from the spirit or scope of the invention.
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