Power plants – Pressure fluid source and motor – Servo-motor having externally operated control valve sets...
Reexamination Certificate
2000-02-04
2003-08-05
Look, Edward K. (Department: 3745)
Power plants
Pressure fluid source and motor
Servo-motor having externally operated control valve sets...
C060S484000, C137S636200
Reexamination Certificate
active
06601386
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lever-operated actuator drive unit and an operating lever unit and, more particularly to a lever-operated actuator drive unit which makes it possible to construct apparatuses readily and an operating lever unit which can be operated without a feeling of physical disorder, such as conventional operating lever units.
2. Description of the Related Art
There is a known invention regarding an operating lever unit. The operating lever unit generates operating signals by tilting operation of one operating lever and controls two hydraulic actuators on the basis of its operating signals.
Unexamined Japanese Patent Publication (kokai) No. 9-89515, for example, discloses an electric operating lever unit which outputs electrical signals corresponding to respective displacements of four pistons by tilting operation of one operating lever. Two hydraulic actuators can be drive-controlled on the basis of the electrical signals outputted from the electric operating lever unit.
Also, International Publication WO96/15374 discloses a hydraulic operating lever unit that outputs oil pressure signals.
FIG.
7
(
a
) shows a main sectional view of the hydraulic operating lever unit which outputs oil pressure signals corresponding to respective displacements of four pistons by tilting operation of one operating lever. FIG.
7
(
b
) shows a perspective view of the construction of a universal joint
50
shown in FIG.
7
(
a
). Also,
FIG. 8
shows an embodiment regarding an actuator drive unit control apparatus which controls the drive of two hydraulic motors mounted on a hydraulic driven vehicle, by the operating lever unit shown in FIG.
7
. Further, FIGS.
12
(
a
) and
12
(
b
) show movements of the operating lever unit shown in FIG.
7
. The above-mentioned unit will be explained with reference to these drawings.
An operating lever unit
5
shown in FIG.
7
(
a
) is generally composed of a unit body
7
and an operating lever
6
tiltably provided onto the unit body
7
.
The operating lever
6
is mounted to the unit body
7
via a universal joint
50
and a diskplate
8
.
That is, the upper portion of the unit body
7
is provided with a mounting plate
11
. Further, as shown in FIGS.
12
(
a
) and
12
(
b
), four pistons
1
,
2
,
3
, and
4
are provided in such a way that tops (upper ends) of the pistons protrude beyond the mounting plate
11
. The pistons
1
,
2
,
3
, and
4
are arranged so as to locate on the four corners of a regular square, with viewed from upper side of the mounting plate
11
. Besides, in place of the regular square, a quadrilateral may be applied. When the operating lever
6
is tilted in a direction F and the piston
4
is pushed down, the vehicle moves forward. Also, when the operating lever
6
is tilted in a direction B and the piston
2
is pushed down, the vehicle moves backward. Further, when the operating lever
6
is tilted in a direction R and the piston
1
is pushed down, the vehicle spins in the clocks direction (or does the right spin-turn). Furthermore, when the operating lever
6
is tilted in a direction L and the piston
3
is pushed down, the vehicle spins in the counterclockwise direction (or does the left spin-turn). By the way, the spin-turn means that the vehicle turns without movement of the center of vehicle. More concretely speaking, the spin-turn means that a pair of wheels or endless tracks mounted to a vehicle rotate in the opposite directions to each other at the same speed whereby the vehicle turns.
FIG.
7
(
a
) is a sectional view viewed from the left side of the operating lever unit shown in FIG.
12
(
a
).
A forked bracket
12
is mounted to the mounting plate
11
of the unit body
7
. As shown in FIG.
7
(
b
), the forked bracket
12
is provided with a tilting piece
13
, via a supporting shaft
10
. The tilting piece
13
is provided with the operating lever
6
, via a supporting shaft
9
. That is, the operating lever
6
is mounted to the unit body
7
via the universal joint
50
.
Both axes of the supporting shaft
9
and supporting shaft
10
are provided so as to be at right angles to each other.
The supporting shaft
9
is parallel to the upper side of mounting plate
11
and perpendicular to the paper surface. The supporting shaft
9
supports the operating lever
6
so as to make it be rotatable about the axis of supporting shaft
9
. That is, the operating lever
6
rotates about the axis of supporting shaft
9
, thereby being capable of tilting in left and right directions in FIG.
7
(
a
).
The supporting shaft
10
is parallel to the upper side of mounting plate
11
and perpendicular to the supporting shaft
9
. The supporting shaft
10
supports the tilting piece
13
relative to the forked bracket
12
so as to make the tiling piece
13
be rotatable about the axis of supporting shaft
10
. That is, the operating lever
6
, with the tilting piece
13
, rotates about the axis of supporting shaft
10
, thereby being capable of tilting in a direction perpendicular to the paper surface in FIG.
7
(
a
).
As mentioned above, the universal joint
50
is composed, so that the operating lever
6
is capable of tilting relative to the unit body
7
in two directions perpendicular to each other.
The disk plate
8
is mounted to the operating lever
6
in such a way that tops (upper ends) of pistons
1
,
2
,
3
, and
4
are in contact with the under surface of the disk plate
8
.
Accordingly, the pistons
4
and
2
(and the pistons
1
and
3
as well, but not shown in
FIG. 7
) move in accordance with a tilting direction and an amount of tilting motion of the operating lever
6
.
The unit body
7
is provided with oil pressure signal generating means which generates oil pressure signals corresponding to the amount of each displacement of each of four pistons
1
,
2
,
3
, and
4
.
FIG. 8
shows a hydraulic circuit of a conventional drive unit with the operating lever unit
5
.
As shown in
FIG. 8
, the operating lever unit
5
is supplied with a pilot pressure oil from a fixed capacitive hydraulic pump
22
. Also, the operating lever unit
5
is connected to a tank
23
.
The pistons
4
,
2
,
1
, and
3
are provided with pressure-reducing valves
18
,
19
,
20
, and
21
, via respective set springs.
Output ports of the pressure-reducing valves
18
,
19
,
20
,
21
are communicated with pilot lines
14
,
15
,
16
, and
17
.
Next, the operation of the operating lever unit
5
will now be explained.
FIG.
7
(
a
) shows a situation wherein the operating lever
6
is in a neutral position. From this situation, when the operating lever
6
is tilted about the axis of supporting shaft
9
toward left side of FIG.
7
(
a
), the piston
4
located on the left side of FIG.
7
(
a
) is pushed down via the disk plate
8
in the direction of arrow A The stroke S (displacement) of the piston
4
becomes a magnitude corresponding to the amount of tilting motion of the operating lever
6
.
When the piston
4
is pushed down, the opening area of the pressure-reducing valve
18
becomes larger through the set spring and then, the pilot pressure is outputted to the pilot line
14
. The pressure of pilot pressure outputted acts on the pressure-reducing valve
18
so as to reduce the opening area thereof. The pilot pressure compresses the set spring, so that the pressure-reducing valve
18
is balanced between the spring force and the pilot pressure. The spring force at the balanced position corresponds to the stroke S and the pilot pressure becomes pressure corresponding to the opening area Therefore, the pilot pressure Pp which is outputted from the pilot line
14
becomes an amount corresponding to the amount of tilting motion of the operating lever
6
.
FIG. 14
shows a relationship between the stroke S of operating lever
6
and the pilot pressure Pp. When the operating lever
6
is operated and the piston
4
moves from a stroke position SO corresponding to the neutral position shown in FIG.
7
(
a
) to a position SF whereat the maximum power Ppmax is outputt
Endo Takeshi
Hori Shuuji
Mototani Masayoshi
Nojiri Mikio
Kershteyn Igor
Komatsu Ltd.
Varndell & Varndell PLLC
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