Marine propulsion – Screw propeller – With means effecting or facilitating movement of propulsion...
Reexamination Certificate
2002-03-28
2002-10-29
Swinehart, Ed (Department: 3617)
Marine propulsion
Screw propeller
With means effecting or facilitating movement of propulsion...
C114S150000
Reexamination Certificate
active
06471556
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tilting mechanism for an outboard motor.
2. Description of the Related Art
FIG. 1
exemplifies a conventional outboard motor, which is attached to a rear portion of a hull of a small-type cruiser, such as a pleasure boat.
The outboard motor
1
is connected to the hull
10
via a bracket
2
. When the outboard motor
1
is tilted up, it rotates upward together with a supporting rod
3
as a rotating axis. In this arrangement, the supporting rod
3
itself rotates around its central axis. At the both ends of the supporting rod
3
, cylinder-support arms
4
are provided. A piston rod
5
is provided so as to connect two cylinder-support arms
4
.
Almost at the center of the piston rod
5
, a piston (not shown) is fixed, and a cylinder tube
6
is placed outside of the piston. Thus, there are provided two piston rooms (or, cylinder rooms) at the both sides of the piston in the cylinder tube
6
. Working fluid, such as working oil, is supplied into the piston rooms inside the cylinder tube
6
from a hydraulic hose
12
, so that the cylinder tube
6
moves to the right and left, as shown by an arrow in FIG.
1
.
The outboard motor
1
is connected to the cylinder tube
6
via a linkage
8
. Thus, along with the movement of the cylinder tube
6
to the right and left, the steering of the outboard motor
1
can be controlled to change the navigating direction of the boat.
In the prior art shown in
FIG. 1
, when the outboard motor
1
is tilted up or down, the cylinder tube
6
also swings up and down around the supporting rod
3
. In the case that the cylinder tube
6
swings along with the tilting movement of the outboard motor
1
, the hydraulic hose
12
itself also swings therewith. This may interfere with the hose arrangement, and depending on the situation, the tilting movement of the outboard motor
1
itself is also prevented.
As another prior art for avoiding the above-mentioned inconvenience, a construction shown in
FIG. 2
is known. In
FIG. 2
, an outboard motor is schematically shown from right above.
In the construction in
FIG. 2
, the outboard motor is to be tilted up around a tilt tube
21
. A connecting rod
23
is connected straight to a piston rod of a cylinder
22
, which is intended for controlling the steering of the outboard motor. The connecting rod
23
extends through the tilt tube
21
, and is connected to the outboard motor via a linkage
24
and a metal fitting
25
. Thus, the steering of the outboard motor can be controlled with the cylinder
22
.
In this prior art, the cylinder
22
is aligned co-axially with the tilt tube
21
, and therefore, the problem as to the hose arrangement can be avoided. But, as can be understood from
FIG. 2
, the overall width of the equipment becomes large, and depending on the transom space (a space on a hull for fixing an outboard motor), the fixation itself of the outboard motor may be difficult.
Further, U.S. Pat. No. 6,276,977, issued to Treinen et al., discloses a construction wherein a cylinder member of an actuator is co-axially arranged with a rotation axis around which an outboard motor rotates, wherein the cylinder member is double-walled construction.
FIGS. 3
to
5
exemplify such a double-walled construction, wherein a one-sided rod relative to a piston is employed. By the way,
FIG. 3
corresponds to FIG.
2
.
In
FIG. 3
, a cylinder
30
serves as a shaft for tilting movement of an outboard motor. A linkage
60
is connected to a rod
31
extending from one end of the cylinder
30
. The linkage
60
is connected to the outboard motor via a metal fitting
61
. When the cylinder rod
31
moves to the right and left in
FIG. 3
, the outboard motor rotates around a point “A”, as shown by an arrow, to change its posture. Thus, the navigating direction of the boat can be controlled. Working fluid is supplied from a hydraulic hose (not shown), via tee joints
65
,
66
, to a first port
41
a
and a second port
42
a
, which will be explained later.
FIG. 4
shows a sectional view of the cylinder mechanism of FIG.
3
. With reference to
FIG. 4
, an outer tube
50
is pressingly fitted into a bore which is formed on a structural portion
1
′ extending from the outboard motor. When the outboard motor is tilted up, the outer tube
50
rotates therewith around its central axis on both sides of the structural portion
1
′, attachment brackets
2
extend from the outboard motor to the hull. The brackets
2
are immobilized, even when the outboard motor is tilted up. Thus, when the outboard motor is tilted up, the outer tube
50
is rotated with sliding movement relative to the brackets
2
. It is to be noted that the outer tube
50
is connected to the brackets
2
, via bushes
51
.
A piston
32
is fixed to one end of the cylinder rod
31
, and an inner tube
40
extends outside the piston
32
with contacting the outer circumference of the piston
32
. Thus, two cylinder rooms
41
,
42
(a first room
41
and a second room
42
) are formed on both sides of the piston
32
. The outer tube
50
is arranged outside the inner tube so as to be co-axially aligned with the inner tube
40
. As shown in
FIG. 5
, a space ‘S’ having a predetermined width is kept between the outer tube
50
and the inner tube
40
. This space ‘S’ serves as a channel for supplying fluid to the cylinder room
42
, as explained below.
The first port
41
a for supplying working fluid to the cylinder room
41
is arranged on an end cover
35
at the left side of the cylinder. The second port
42
a
for supplying working fluid to the cylinder room
42
is also arranged on the end cover
35
. That is, the first and the second ports
41
a
,
42
a
are both arranged on the same one end of the cylinder
30
. Although the both ports are arranged on the left end of the cylinder
30
in
FIG. 4
, they can be arranged on the right end thereof, of course.
The working fluid from the first port
41
a
passes through a channel
41
b
into the cylinder room
41
. On the other hand, the working fluid from the second port
42
a
passes through a channel
42
b
into the space ‘S’, then it moves up to the right end in the space ‘S’, and it turns into the cylinder room
42
. This is shown in FIG.
5
.
FIG. 5
is an enlarged sectional view, which corresponds to the region inside the circle in FIG.
4
.
In the above-mentioned double-walled construction, both of the tee joints
65
,
66
can be arranged on one end of the cylinder, so that the hose arrangement can be simple, and the outward appearance can also be simple.
Further, since two tee joints
65
,
66
can be arranged on one end of the cylinder, locating one end of the cylinder inside the hull would bring a benefit that its hose system does not appear on exterior of the hull. In such a constitution, not only the exterior of the hull can be smart, but also the hose system inside the hull can be protected from sea breeze, so that corrosion can be avoided to improve the durability.
FIGS. 6 and 7
exemplify another conventional double-walled construction. By the way,
FIG. 6
corresponds to FIG.
4
. That is,
FIG. 6
is a sectional view showing the double-walled construction. Although, in the double-walled construction shown in
FIGS. 3
to
5
, only one end of the cylinder rod
31
extends outward from the cylinder
30
, both ends of the cylinder rod extend outward from the both ends of the cylinder in FIG.
6
.
In
FIG. 6
, the piston
32
is fixed to center of the cylinder rod
31
rather than the end of the cylinder. A rod portion
31
a
passes through the cylinder room
41
to outside of the cylinder, and a rod portion
31
b
passes through the cylinder room
42
to outside of the cylinder.
FIG. 7
is an enlarged sectional view, which corresponds to the region inside the circle in FIG.
6
. As shown in this enlarged view, the working fluid from the port
41
a
passes through a channel
41
c
into the cylinder room
41
. The channel
41
c
is annular and extends around the rod portion
31
a.
In the one-sid
Fukuda Takahiro
Kitahara Tomonao
Uchida Tatsumi
Yamashita Ryuji
Merchant & Gould P.C.
Swinehart Ed
Unikas Industrial Inc.
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