Note: Claims are shown in the official language in which they were submitted.
The invention claimed is:
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 with 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.
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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.
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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
38
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 with 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
39
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 roatatable 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 roatatable
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.
41
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 watercraft supports 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 watercraft
supports
being configured to receive and support the watercraft, the combined port and
starboard internal chambers having sufficient internal volume that when
sufficient
42
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 watercraft supports 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.
43
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.
44
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 watercraft support
and having an internal chamber configured to receive and release pressurized
air,
and a starboard air tank with a starboard watercraft support and having an
internal
chamber configured to receive and release pressurized air, the port and
starboard
watercraft supports 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 watercraft supports 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.
46
48. The watercraft lift of claim 47 wherein the port watercraft support
is a bunk attached to the port air tank in a manner to provide longitudinal
rigidity to
the port air tank, and the starboard watercraft support is a bunk 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 roatatable 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
47
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
roatatable 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 and
having an internal chamber configured to receive and release pressurized air,
and a
starboard air tank with a starboard support bunk 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;
48
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 roatatable 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
49
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 and
having an internal chamber configured to receive and release pressurized air,
and a
starboard air tank with a starboard support bunk 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.
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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 and
having an internal chamber configured to receive and release pressurized air,
and a
starboard air tank with a starboard support bunk 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.
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