Implements or apparatus for applying pushing or pulling force – Apparatus for hauling or hoisting load – including driven... – Device includes rotatably driven – cable contacting drum
Reexamination Certificate
1999-06-24
2001-01-30
Walsh, Donald P. (Department: 3653)
Implements or apparatus for applying pushing or pulling force
Apparatus for hauling or hoisting load, including driven...
Device includes rotatably driven, cable contacting drum
C254S365000
Reexamination Certificate
active
06179271
ABSTRACT:
BACKGROUND OF THE INVENTION
1. (Field of the Invention)
The present invention relates to a hydraulic winch for driving a winch drum by means of a hydraulic motor.
2. (Description of the Related Art)
Conventionally, a hydraulic winch mounted on a crane or the like is generally provided with a free-fall operating mode separately from a power operating mode for winding up-and-down a load (hanging goods) by means of a motor whereby a winch drum is rotated down by the load in the free-fall operating mode to freely lower the load (see Japanese Patent Application Laid-Open No. 9-216793 Publication which is hereby fully incorporated by reference).
The constitution of the conventional hydraulic winch provided with the free-fall operating mode as described above will be explained hereinafter with reference to
FIGS. 28
to
31
.
FIG. 28
schematically shows the constitution of a winch main body portion. In this figure, reference numeral
1
designates a winch drum, and reference numeral
2
designates a hydraulic motor (hereinafter referred to as a winch motor) as a drive source for the winch drum
1
. A planetary gear mechanism
3
for performing power transmission is provided between an output shaft
2
a
of the winch motor
2
and the winch drum
1
.
Reference numeral
4
designates a sun gear of the planetary gear mechanism
3
,
5
a planetary gear,
6
a ring gear provided in the inner periphery of the winch drum
1
,
7
a carrier for supporting the planetary gear
5
,
8
a carrier shaft, and
9
a multidisk provided on the carrier shaft
8
. The multidisk
9
, a pressure plate
10
for actuating (pressing) and deactuating (alienating) the disk
9
, a brake cylinder
11
for driving the pressure plate
10
, and a pressing spring
12
constitute a hydraulic brake and a clutch in one
13
for connecting the winch drum
1
to and separating it from the output shaft
2
a
of the motor and braking the free-fall rotation of the drum
1
.
The multidisk
9
comprises a plurality of inner plates (a first frictional plate)
14
. . . mounted on the carrier shaft
8
integrally rotatably and axially movably, and a plurality of outer plates (a second frictional plate)
16
mounted on a brake casing
15
in a state of being axially movably and non-rotatable with respect to the inner plates
14
. When both the inner and outer plates
14
and
16
are pressed between one side wall
15
a
of the brake casing
15
and the pressure plate
10
, the brake (clutch) is turned on, and when they are separated, the brake (clutch) is turned off.
The pressing spring
12
is provided between the other side wall
15
b
of the brake casing
15
and the pressure plate
10
to apply a spring force in a direction of turning on the brake to the pressure plate
10
.
The brake cylinder
11
has a dual-rod type piston
11
P, a positive-side oil chamber
11
a
for pressing the pressure plate
10
in a direction of turning on the brake (in a right direction in the figure), and a negative-side oil chamber
11
b
for pressing the pressure plate
10
in a direction of turning off the brake (in a left direction in the figure). A negative line
17
connected to the negative-side oil chamber
11
b
is directly connected to a brake hydraulic source
18
.
On the other hand, a positive line
19
connected to the positive-side oil chamber
11
a
is branched into two lines through a high pressure selection valve (a shuttle valve)
20
, one branched line and the other branched line being connected to the hydraulic source
18
or a tank T through an electromagnetic type mode switching valve
21
and a brake valve (a reduction valve)
22
, respectively.
The mode switching valve
21
is switched between a brake position a and a free-fall position (a brake release position) b by operation of a mode switching switch not shown, so that the positive-side oil chamber
11
a
is connected to the hydraulic source
18
at the brake position a and to the tank T at the free-fall position b, respectively.
The brake valve
22
is operated by a pedal
23
, and a secondary pressure according to an operating amount thereof is supplied to the positive-side oil chamber
11
a
of the brake cylinder
11
through the high pressure selection valve
20
.
With this constitution, the following operations are obtained:
{circle around (1)} In the state that the mode switching valve
21
is set to the brake position a, both the side oil chambers
11
a
and
11
b
of the brake cylinder
11
are in the same pressure, and therefore, thrust is not generated in the brake cylinder
11
in itself but the pressure plate
10
along with the brake cylinder
11
is pressed by the spring force of the pressing spring
12
toward the multidisk
9
(in the direction on which brake exerts) to turn the brake on.
In this state, the carrier shaft
8
remains to be non-rotatable so that the turning force of the winch motor
2
is transmitted to the winch drum
1
through the planetary gear mechanism
3
, and the winch drum
1
rotated to be wound up or down according to the operation of a remote control valve not shown.
{circle around (2)} When the mode switching valve
21
is switched to the free-fall position b, the positive-side oil chamber
11
a
of the brake cylinder
11
comes in communication with the tank T to generate a pressure difference between the positive-side oil chamber
11
a
and the negative-side oil chamber
11
b
, and the thrust of the brake cylinder
11
exceeds the spring force of the pressing spring
12
due to the pressure difference whereby the brake cylinder
11
is pressed in the direction opposite to the multidisk
9
(in the direction of releasing the brake) to turn the brake off.
In this state, the carrier shaft
8
is fee so that the winch drum
1
assumes a state capable of being freely rotated in the winding-down direction due to the load, that is, a state capable of achieving the free-fall.
When at this time, the brake valve
22
is operated, the multidisk
9
is turned on due to the secondary pressure according to an operating amount thereof, and the brake force exerts on the winch drum
1
.
On the other hand, the concrete constitution of the body portion of the hydraulic winch of this kind is shown in
FIGS. 29
to
31
, in which the same parts as those used in
FIG. 28
are indicated by the same reference numerals.
A positive-side rod
24
and a negative-side rod
25
are integrally provided on one side of a piston
11
P and on the opposite side thereof, respectively.
Both the side rods
24
and
25
are formed to be hollow shafts, and a pressure plate
10
is mounted on the extreme end of the negative-side rod
5
through a connecting plate
26
.
Reference numerals
27
and
27
designate bolts for mounting a pressure plate, and
28
designates an inner plate mounting body secured to the outer circumference of a carrier shaft
8
. Inner plates
14
. . . of a multidisk
9
are axially movably mounted in the outer periphery of the mounting body
28
.
A positive-side oil chamber
11
a
and a negative-side oil chamber
11
b
of the brake cylinder
11
are formed between a cylinder end plate
29
and the piston
11
P and between the piston
11
P and a side wall
15
b
of a brake casing
15
, respectively, and connected to a positive line
19
and a negative line
17
through oil paths
30
and
31
.
However, the aforementioned conventional hydraulic winch has the following problems:
(I) Overstroke of the piston
11
P in the brake cylinder
11
:
As shown in an enlarged scale in
FIG. 30
, the pressure plate
10
is provided in its center with a fitting hole
10
a
, in which a connecting plate
26
is fitted.
The connecting plate
26
is provided on one end thereof with a collar-like portion
26
a
, and in the state that the collar-like portion
26
a
stops at the peripheral edge portion of the fitting hole
10
a
of the pressure plate
10
from the multidisk
9
side, the pressure plate
10
is connected by means of bolts
27
and
27
to the piston
11
P of the brake cylinder
11
(and both the rods
24
and
25
).
Thereby, the cylinder thrust
Tanji Masato
Yamagata Katsuki
Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd).
Marcelo Emmanuel M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Walsh Donald P.
LandOfFree
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