Valves and valve actuation – With correlated flow path – Valve operated by joining flow path sections
Reexamination Certificate
2000-01-11
2001-09-04
Lee, Kevin (Department: 3754)
Valves and valve actuation
With correlated flow path
Valve operated by joining flow path sections
C385S046000, C385S046000
Reexamination Certificate
active
06283443
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a chuck and a tube joint. In particular, the present invention relates to a tube joint and a chuck preferable to facilitate the improvement in productivity of the tube joint and the realization of a compact size and a light weight of the tube joint.
2. Description of the Related Art
In general, as shown in
FIG. 15
, for example, a tube joint comprises a tubular first tube joint member
300
, a tubular second tube joint member
302
to be coupled to the first tube joint member
300
, a sleeve
304
attached to a coupling portion between the first and second tube joint members
300
,
302
, for coupling and releasing the first and second tube joint members
300
,
302
, a compressive coil spring
306
for urging the sleeve
304
in a direction to couple the first and second tube joint members
300
,
302
to one another, and a plurality of balls
308
for engaging the first and second tube joint members
300
,
302
with each other.
The first tube joint member
300
includes a cylindrical member
312
which has its front portion to be inserted into the sleeve
304
and which has a female screw
310
threaded on its rear portion, and a coupling member
314
having a cylindrical configuration which is screwed into the female thread of the cylindrical member
312
. An accommodating space
318
for accommodating a valve plug
316
is formed at a front portion of the coupling member
314
. A closing plate
324
, which is provided with a slit
322
for inserting a part of the valve plug
316
, is installed between the cylindrical member
312
and the coupling member
314
. A compressive coil spring
328
is inserted into the accommodating space
318
, for always urging the valve plug
316
in the direction toward the closing plate
324
to close the slit
322
with a flange
326
of the valve plug
316
.
The sleeve
304
is installed such that its end surface
304
a
is flushed with an end surface
312
a
of the cylindrical member
312
of the first tube joint member
300
. The sleeve
304
is always urged resiliently by the compressive coil spring
306
in the direction to make separation from the first tube joint member
300
toward the second tube joint member
302
. However, the sleeve
304
is suppressed so that it is not disengaged from the first tube joint member
300
, by the aid of a ring-shaped stopper member
330
which is installed in the vicinity of the end surface
312
a
of the cylindrical member
312
.
The cylindrical member
312
of the first tube joint member
300
has a plurality of holes
332
which are formed at its front end portion (portion overlapped with the second tube joint member
302
), the holes
332
being formed at positions disposed at equal intervals along the circumferential direction of the cylindrical member
312
. The diameter of each of the holes
332
is reduced toward the central axis of the cylindrical member
312
, and the balls
308
are inserted into the holes
332
respectively. The ball
308
is arranged such that a part of the ball
308
is inserted into and engaged with an annular groove
334
formed on the surface of the second tube joint member
302
, when the second tube joint member
302
is inserted into the hollow portion of the cylindrical member
312
.
FIG. 15
is illustrative of a case in which only two of the holes
332
and the balls
308
are shown respectively.
Usually, the balls
308
are pressed toward the central axis of the cylindrical member
312
by the aid of the sleeve
304
. However, when an external force is applied to the sleeve
304
to move the sleeve
304
toward the coupling member
314
along the axial direction of the first tube joint member
300
, the balls
308
are released from the pressing action of the sleeve
304
. In this situation, the valve plug
316
is operated such that the flange
326
thereof abuts against the closing plate
324
to close the slit
322
by being urged by the compressive coil spring
328
. Thus, the valve plug
316
is in the closed state.
Starting from this stage, when the second tube joint member
302
is inserted into the hollow portion of the cylindrical member
312
of the first tube joint member
300
, the valve plug
316
is moved rearwardly against the urging force of the compressive coil spring
328
by means of the end surface of the second tube joint member
302
. Thus, the valve plug
316
is in the open state.
When the external force applied to the sleeve
304
is removed, the sleeve
304
is resiliently urged in accordance with the elastic restoration of the compressive coil spring
306
. Accordingly, the sleeve
304
is restored to the position at which the end surface
304
a
of the sleeve
304
is flushed with the end surface
312
a
of the cylindrical member
312
.
In this state, the balls
308
are pressed by the sleeve
304
again toward the central axis of the cylindrical member
312
. As a result, the balls
308
are engaged with the annular groove
334
provided on the second tube joint member
302
.
The engagement of the balls
308
disables the second tube joint member
302
from being disengaged from the first tube joint member
300
. Therefore, the first and second tube joint members
300
,
302
are tightly joined to one another.
When the tube joint as described above is produced, an inconvenience arises in that the production cost cannot be made inexpensive, because the production steps are complicated.
The inconvenience will be specifically explained below. As described above, the conventional tube joint comprises the four balls
308
, and the sleeve
304
for pressing the balls
308
toward the central axis of the tube joint. When such a tube joint is assembled, complicated operations must performed, including (1) formation of the holes
332
of the cylindrical member
312
for constructing the first tube joint member
300
, (2) insertion of the balls
308
into the holes
332
, and (3) installation of the sleeve
304
while pressing the balls
308
by using a jig so that the balls
308
are not disengaged from the holes
332
. Further, it takes a long period of time to perform the operations.
The cylindrical member
312
and the coupling member
314
of the first tube joint member
300
are mutually different members, and it is also complicated and troublesome to connect them to one another (by means of screwing operation). Therefore, it is not easy to improve the production efficiency of the tube joint, resulting in the increase in the production cost of the tube joint.
It has been hitherto demanded for the tube joint to have a compact size and a light weight because of the following reason. That is, if the tube joint has a large size, the degree of freedom is restricted for the arrangement of the tube. Further, when the tube joint is connected with the tube, then the tube joint interferes with, for example, another tube and equipment, and it is difficult to perform the connecting operation in some cases. In the latter case, there is a likelihood that the connection between the tube and the tube joint may be incomplete, and it is feared that the sealing performance may be insufficient.
If the tube joint has a large weight, the tube connected with the tube joint may be bent due to the weight of the tube joint. In this case, it is also feared that the connection between the tube and the tube joint may be incomplete, and it is impossible to obtain any sufficient sealing performance.
In the case of the conventional tube joint as described above, it is necessary to provide a sufficiently long size of the first tube joint member
300
, especially of the cylindrical member
312
along the axial direction, in order to ensure the space for inserting the balls
308
. Further, the coupling member
314
is coupled by being screwed to the rear portion of the cylindrical member
312
. Therefore, the length of the tube joint along the axial direction is necessarily increased, and hence the weight is also increased in accordance therewith.
Further, it is demanded to obtai
Lee Kevin
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
SMC Kabushiki Kaisha
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