US 4,787,327 A · Lift for marine craft

Abstract

According to the invention, a lift is provided having base beams, first and second pairs of lifting arms and lifting rails. The lifting arms have one end pivotally mounted to the base beams for rotation about parallel axes with the common plane of the axes residing substantially in a horizontal orientation. The other ends of the lifting arms pivotally connect to the lifting rails to define, when viewed from the side, a closed linkage that permits the lifting rails to be raised and lowered relative to the base upon the lifting arms being simultaneously pivoted. The bow pair of lifting arms are longer than the stern pair of lifting arms, and the distance between the pivots on the base beams is greater than the distance between the pivots on the rails so that the linkage cannot lock-up when in the loading position and so that a craft resting on the rails is inclined with the bow above the stern for drainage. A cross bar defining one pivot center is engaged by the bottom of the rails when the lift is in the loading position whereby the box lifting arms form an angle with the beams that not only prevents the linkage from locking up but also minimizes the initial lifting force needed to raise the rails and a boat docked thereon.

Claims22

Dependent claims

A lift for elevating a boat relative to a support surface, said lift comprising:

an elongate base beam;
means for supporting the base beam on the support surface;
a first lifting arm;
means mounting one portion of the first lifting arm for pivoting movement relative to the base beam about a first axis that is transverse to the length of the base beam;
a second lifting arm;
means mounting one portion of the second lifting arm for pivoting movement relative to the base beam about a second axis that is parallel to said first axis and spaced lengthwise of the base beam from the first axis;
a lifting rail having a boat engaging surface;
means mounting a second portion of the first lifting arm to the lifting rail for pivoting movement relative to the lifting rail about a third axis that is parallel to and spaced from said first axis;
and
means mounting a second portion of the second lifting arm to the lifting rail for pivoting movement relative to the lifting rail about a fourth axis that is parallel to and spaced from said second axis,
said first and third axes residing in a first plane, said third and fourth axes residing in a second plane, said second and fourth axes residing in a third plane and the first and second axes reside in a fourth plane,
said first, second, third and fourth planes cooperatively enclosing a trapezium,
whereby with the fourth plane within which the first and second axes reside horizontally oriented, the second plane within which the third and fourth axes reside is non-horizontal and tilts downwardly from the third axis toward the fourth axis.

10 more elements

A lift for elevating a boat relative to a support surface, said lift comprising:

an elongate base beam;
means for supporting the base beam on the support surface;
a first lifting arm;
means mounting one portion of the first lifting arm for pivoting movement relative to the base beam about a first axis that is transverse to the length of the base beam;
a second lifting arm;
means mounting one portion of the second lifting arm for pivoting movement relative to the base beam about a second axis that is parallel to said first axis and spaced lengthwise of the base beam from the first axis;
a lifting rail having a boat engaging surface;
means mounting a second portion of the first lifting arm to the lifting rail for pivoting movement relative to the lifting rail about a third axis that is parallel to and spaced from said first axis;
and
means mounting a second portion of the second lifting arm to the lifting rail for pivoting movement relative to the lifting rail about a fourth axis that is parallel to and spaced from said first axis;
the spacing between the first and third axes being greater than the spacing between the second and fourth axes,
whereby with a plane within which the first and second axes reside horizontally oriented, the boat engaging surface is inclined so that a boat placed thereon will be in a tilted position,
wherein said third and fourth axes are spaced apart a less distance than are the first and second axes which space difference combines with the space difference between the first and third axes and the second and fourth axes to facilitate raising and lowering the rails and a boat on the rails.

10 more elements

A lift for a marine craft having a hull with an underside surface, said lift comprising:

a base having a pair of parallel spaced apart beams jointed together by a pair of cross bars;
a first pair of lifting arms;
means mounting one portion of the first pair of lifting arms to the opposite end portions of one of the cross bars for pivoting movement about a first axis of the one cross bar;
a second pair of lifting arms;
means mounting one portion of the second pair of lifting arms to the opposite end portions of the other of the cross bars for pivoting movement about a second axis defined by the other cross bar that is spaced from and parallel to the first axis;
a pair of lifting rails for bearing on the underside surface of the hull;
and
means for pivotally connecting the lifting rails to the first pair and second pair of lifting arms for pivoting movement about a third and a fourth axis which third and fourth axes are parallel to each other and are parallel to the first and second axes, said first pair of lifting arms having a length that is longer than the length of the second pair of lifting arms whereby with the first and second axes lying a horizontal plane, the craft on said lifting rails is in a non-horizontal orientation and whereby pivoting the first and second pairs of lifting arms about said first and second axes will raise and lower the lifting rails relative to the base,
wherein the lengths of the lifting rails between the third and fourth axes are less than the lengths of the beams between the first and second axes so that the plane of the third and fourth axes is at an angle with the plane of the first and second axes to facilitate lifting the craft initially from the water.

6 more elements

A lift for a marine craft having a hull with an underside surface, said lift comprising:

a base having a pair of parallel spaced apart beams joined together by first and second spaced apart and parallel cross bars;
a first pair of lifting arms having a predetermined length;
means mounting one portion of the first pair of lifting arms to the opposite end portions of one of the cross bars for pivoting movement about an axis of said first cross bar;
a second pair of lifting arms having a predetermined length;
means mounting one portion of the second pair of lifting arms to the opposite end portions of the second cross bar for pivoting movement about an axis of the second cross bar that is spaced from and parallel to the axis of the first cross bar;
a pair of lifting rails for bearing on the underside surface of the hull;
means for pivotally connecting the lifting rails to the first pair and second pair of lifting arms for pivoting movement about a third and a fourth axis which third and fourth axes are parallel to each other and are parallel to the first and second cross bars, whereby with the first and second cross bars lying in a horizontal plane, the craft on said lifting rails is in a non-horizontal orientation;
the lengths of the lifting rails between the third and fourth axes are less than the lengths of the beams between the first and second axes whereby a plane defined by the third and fourth axes is at an angle to a plane defined by the first and second axes to facilitate draining of a craft on the rails and to facilitate lifting the craft from the water;
and
means for pivoting the first and second pairs of lifting arms about the axes of said first and second cross bars for raising and lowering the lifting rails and craft relative to the base.

7 more elements

A lift for a marine craft having a hull with an underside surface, said lift comprising:

a base having a pair of parallel spaced apart beams joined together by first and second spaced apart and parallel cross bars, each said cross bar having opposite end portions and an axis;
a first pair of lifting arms having a predetermined length;
means mounting one portion of the first pair of lifting arms to the opposite end portions of the first cross bar for pivoting movement about the axis of said first cross bar;
a second pair of lifting arms having a predetermined length shorter than the first pair of lifting arms;
means mounting one portion of the second pair of lifting arms to the opposite end portions of the second cross bar for pivoting movement about a second axis of the second cross bar that is spaced from and parallel to the axis of the first cross bar;
a pair of lifting rails for bearing on the underside surface of the hull;
means for pivotally connecting the lifting rails to the first pair and second pair of lifting arms for pivoting movement about a third and a fourth axis which third and fourth axes are parallel to each other and are parallel to the first and second cross bars, whereby with the first and second cross bars lying in a horizontal plane, the craft on said lifting rails is in a non-horizontal orientation;
and
means for pivoting the first and second pairs of lifting arms about the axes of said first and second cross bars for raising and lowering the lifting rails and craft relative to the base,
wherein said third axis is defined by a third cross bar, said fourth axis is defined by a fourth cross bar and said means for pivoting the first and second pairs of lifting arms comprises a winch operatively connected with said fourth cross bar,
wherein the length of the lifting rails between the third and fourth cross bars is less than the length of the beams between the first and second cross bars so that the plane of the third and fourth cross bars is at an angle with the plane of the first and second cross bars to facilitate lifting and craft initially from the water.

8 more elements

Dependencies are inferred from the claim text.

Lift for marine craft

Life of this patent

Lift for marine craft

Life of this patent

Abstract

Claims22