Fluid handling – Systems – Flow path with serial valves and/or closures
Reexamination Certificate
2000-06-05
2002-05-21
Lee, Kevin (Department: 3753)
Fluid handling
Systems
Flow path with serial valves and/or closures
C137S614030, C137S614050
Reexamination Certificate
active
06390126
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a coupling device having a male coupler and a female coupler. More particularly, the present invention relates to an improved coupling device having a valve at the outlet of a female coupler adapted for having a certain shut-down property to prevent a fluid from leaking out from the female coupler.
A variety of conventional coupling devices, each comprising a male coupler and a female coupler, have been introduced for practical use in industrial machines to detachably connect one fluid path to the other in a fluid supply system (e.g. of hydraulic or pneumatic system). For example, a work pallet for detachably holding one or more works to be machined by a machining center includes one or more hydraulic clamping apparatuses. A coupling device is commonly provided for connecting a hydraulic path to the hydraulic clamping apparatus for supplying a hydraulic pressure.
Referring to
FIGS. 8
to
10
, a conventional coupling device
100
, developed by the same applicants as of the present invention, includes a male coupler
101
, a female coupler
102
, and a hydraulic cylinder
103
.
While male coupler
101
is fixed with a plurality of bolts
104
, female coupler
102
is located lower than male coupler
101
and joined to hydraulic cylinder
103
for moving forward and backward. Female coupler
102
is installed in a cylinder body
105
of hydraulic cylinder
103
and is driven by hydraulic cylinder
103
, moving between a coupled position and a separated position.
Male coupler
101
has a protruded cylindrical portion provided at the lower end thereof which can be inserted into the upper end of female coupler
102
. When the male and female couplers
101
and
102
are coupled to each other (see FIG.
10
), both a main opening/closing valve
106
and an auxiliary opening/closing valve
107
in male coupler
101
open their hydraulic passages. When the male and female couplers
101
and
102
are separated from each other (see FIGS.
8
and
9
), both main valve
106
and auxiliary valve
107
in male coupler
101
shut down their hydraulic passages.
As a valve shaft
109
of auxiliary valve
107
in the coupled position retracts in an upward direction relative to the protruded cylindrical portion, its valve body portion
110
comes into direct contact, with metal touch, with the annular tapered face of a valve seat portion
108
of auxiliary opening/closing valve
107
. Therefore, auxiliary valve
107
is constituted as a seat type valve.
When the male and female couplers
101
and
102
are in the coupled position (see FIG.
10
), both a main opening/closing valve
111
and an auxiliary opening/closing valve
112
in the female coupler
102
open their hydraulic passages. In the separated position (see FIGS.
8
and
9
), both main valve
111
and auxiliary valve
112
shut down their hydraulic passages. As shown in
FIG. 9
, while main valve
111
shuts down its hydraulic passage in the separated position, the passage between a cylindrical member
113
and a shaft member
114
of auxiliary valve
112
is closed. Because shaft member
114
moves into the protruded cylindrical portion of male coupler
101
in the coupled position as shown in
FIG. 10
, it is difficult to constitute auxiliary opening/closing valve
112
as a seat type valve. Accordingly, auxiliary valve
112
permits its shaft member
114
to fit at its distal end into a valve face opening of cylindrical member
113
for closing the passage. The distal end of cylindrical member
113
is thus equipped with an annular seal element
115
made of a synthetic resin material to seal off the lower end of the protruded cylindrical portion of male coupler
101
in the coupled position.
When connected to a hydraulic source provided with a oil pressurizing means, such as an electric pressure pump, the system is supplied with a hydraulic oil which may contain some air. As a result, when the male and female couplers
101
and
102
are separated from each other, minute bubbles of air may be trapped in female coupler
102
and then leak out with oil from auxiliary valve
112
, resulting in a loss of the hydraulic oil and polluting the environment of the coupling device.
For example, by providing a separable structure of shaft member
114
of female coupler
102
, it is possible to constitute the auxiliary opening/closing valve
112
as a seat type valve like that of male coupler
101
. However, the internal pressure in female coupler
102
is decreased close to an ambient pressure in the separated position, hardly pressing against the seat portion. Accordingly, the leakage of air and oil from auxiliary opening/closing valve
112
is unavoidable. In addition, because the oil of higher pressure which leaked from main opening/closing valve
111
may act on the distal end of female coupler
102
and exert a large force against shaft member
114
, it is an adverse idea to decrease the diameter of shaft member
114
.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a coupling device which overcomes the foregoing problems.
More specifically, it is an object of the present invention to provide a coupling device which can prevent any leakage of a fluid from an auxiliary opening/closing valve in its female coupler with a simple arrangement.
It is a further object of the present invention to provide a coupling device which seals the fluid containing air in the female coupler, even if the pressure of the fluid remains or is as low as the ambient pressure level when its two couplers are separated from each other.
The coupling device according to the present invention has a male coupler and a female coupler capable of detachably coupling with the male coupler to connect and disconnect the passage of a pressurized fluid.
Briefly stated, the present invention provides a coupling device, having a simple structure, which prevents leakage of fluid from an auxiliary valve in a female coupler. The coupling device seals fluid containing air in the female coupler, even in the pressure of the fluid remains or is as low as the ambient pressure level when the male coupler is separated from the female coupler. An annular seal, having integrally formed first and second annular seal elements, is provided in the female coupler. The first annular seal seals between a protruded cylindrical member of the male coupler and a mating cylindrical member of the female coupler. The second annular seal forms a valve body portion of the cylindrical member of the female coupler.
According to one embodiment of the present invention, there is provided a coupling device having a male coupler and a female coupler, wherein said male coupler and said female coupler fit together to connect a passage of a fluid, wherein: the male coupler includes a first valve mechanism having a protruded cylindrical member; a valve shaft axially movable in an interior of the protruded cylindrical member; a first valve body portion on the valve shaft; the valve body portion engaging and disengaging from the interior with a valve seat portion provided in the protruded cylindrical member, thereby shutting down the passage of the fluid between the protruded cylindrical member and the valve shaft; and a first spring, urging the first valve shaft toward a closed position; the female coupler includes a second valve mechanism having a main body case with an engaging bore provided therein; the engaging bore fitting with the protruded cylindrical member; a shaft member mounted in the main body case; a cylindrical member, fitted on the shaft member, axially movable and positioned opposite to a distal end of the protruding cylindrical member; a second valve body portion provided on the cylindrical member, engaging and disengaging from an inner side with a cylindrical valve face portion; the cylindrical valve face portion provided near a distal end on the shaft member, thereby shutting down the passage of the fluid between the cylindrical member and the shaft member; and a second spring, urging the cylindri
Lee Kevin
Morrison Law Firm
Pascal Kabushiki Kaisha
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