Valves and valve actuation – Mechanical movement actuator – Screw
Reexamination Certificate
1999-08-09
2001-03-06
Shaver, Kevin (Department: 3754)
Valves and valve actuation
Mechanical movement actuator
Screw
C251S264000, C251S275000, C251S277000, C251S278000, C251S285000, C251S331000
Reexamination Certificate
active
06196523
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a manually opened and closed stop valve.
2. Description of the Related Art
The manually opened and closed stop valve of this type is adapted to bring a closure member into closing contact with a valve seat by a thrust of a thrust screw member, which results from advancing the thrust screw member to a housing through a tightening rotation of a handle.
However, when the handle is excessively tightened by mistake, the thrust screw member produces an overmuch thrust, which excessively pushes the closure member to the valve seat. This causes either or both of the valve seat and the closure member to make plastic deformation, which results in a likelihood of worsening the shut-off efficiency of the stop valve.
In order to prevent the foregoing excessive tightening, it is considered to prohibit the thrust screw member from further moving in a direction for valve closing over a predetermined distance, by a stopper fixed within the housing.
In this case, however, there are produced the following new problems.
For any reason, a foreign matter may bite into a space between the closure member and the valve seat. Or if the opening and closing operation is repeatedly conducted, it causes a sealing surface of the valve seat to wear off too much. In these cases, the closure member needs to be brought into closing contact with the valve seat more strongly.
However, as mentioned above, provided that the stopper prohibits the thrust screw member from further moving for valve closing over the predetermined distance, it is impossible to conduct further extra-tightening, which results in failing to satisfy the above-mentioned need.
SUMMARY OF THE INVENTION
The present invention has an object of making it possible to prevent the excessive tightening and at the same time readily conduct the extra-tightening.
In order to accomplish the object, the present invention includes a stop valve in the following manner, for example, as shown in each of
FIGS. 1
to
6
.
The stop valve is adapted to bring a closure member
12
into closing contact with a valve seat
15
by a thrust of an output portion
27
connected to a thrust screw member
23
, which results from advancing the thrust screw member
23
to a housing
2
through a tightening rotation of a handle
26
, wherein
a stopper member
20
is provided between the housing
2
and a valve-closing thrust transmission system (T) which extends from the handle
26
to the output portion
27
, the stopper member
20
being arranged so as to be able to be switched over to a stopping condition (X) which prevents the output portion
27
from further moving for valve closing over a predetermined distance and to a stop cancelling condition (Y) which allows the output portion
27
to further move for valve closing over the predetermined distance.
The present invention can result in the following function and effect.
While the stop valve is in normal use, the stopper member is switched over to the stopping condition. Thus even if the handle is excessively tightened by mistake, the stopper member can prevent the output portion of the valve-closing thrust transmission system from further moving for valve closing over the predetermined distance. This makes it possible to prohibit the closure member from being excessively pushed to the valve seat. As a result, either or both of the valve seat and the closure member can be prevented from making plastic deformation, which enables the stop valve to keep a good shut-off efficiency.
In the event that extra-tightening is required for any reason, the stopper member is switched over to the stop cancelling condition, thereby allowing the output portion to further move for valve closing over the predetermined distance. Therefore, extra-tightening of the handle can further advance the thrust screw member in a direction for valve closing. The thus resulting thrust of the thrust screw member causes the output portion to strongly move the closure member for valve closing. As a result, the closure member is brought into stronger closing contact with the valve seat. As such, the extra-tightening has been readily conducted only by switching over the stopper member from the stopping condition to the stop cancelling condition.
In consequence, it has become possible to prevent the excessive tightening and at the same time easily conduct the extra-tightening.
The present invention is preferably added with the following construction.
For instance, as shown in
FIGS. 1
, and
2
there is provided between the thrust screw member
23
and the closure member
12
, an intermediate transmission member
25
separate from the thrust screw member
23
. The intermediate transmission member
25
has one end connected to the closure member
12
and has the other end provided with a receiving portion (B). The stopper member
20
is provided with a stopping portion (A) which axially faces the receiving portion (B).
According to the present invention, when rotating the handle for tightening purpose, relative rotation occurs around an axis mainly between the thrust screw member and the intermediate transmission member, but it can be inhibited from resulting around the axis between the intermediate transmission member and the closure member. This can inhibit members which exist between the receiving portion of the intermediate transmission member and the output portion from wearing off to axially shorten. As a result, it is possible to prevent the closure member from gradually reducing an amount of its movement for valve closing due to repeated opening and closing operation of the stop valve and therefore retain the amount of its movement for valve closing at a predetermined value over a prolonged period of time.
The present invention is preferably added with the concrete structure as further in the specification.
Besides, in order to accomplish the above-mentioned object, the present invention includes a stop valve in the following manner, for example, as shown in
FIG. 7
or FIG.
8
.
The stop valve is adapted to bring a closure member
12
into closing contact with a valve seat
15
by a thrust of an output portion
27
connected to a thrust screw member
23
, which results from advancing the thrust screw member
23
to a housing
2
through a tightening rotation of a handle
26
, wherein
an intermediate transmission member
25
is interposed between the thrust screw member
23
and the output portion
27
, the intermediate transmission member
25
being supported by the thrust screw member
23
so as to be axially movable,
and the housing
2
is provided with a stopper member
20
which prevents the thrust screw member
23
from further moving in a direction for valve closing over a predetermined distance,
the thrust screw member
23
engaging with an extra-tightening bolt
46
in screw-thread fitting so as to be able to axially advance and retract the bolt
46
, the extra-tightening bolt
46
having one end opposing to the intermediate transmission member
25
and having the other end provided with a rotation actuating portion
47
.
The present invention can result in the following function and effect.
While the stop valve is in normal use, even if the handle is excessively tightened by mistake, the stopper member can prevent the thrust screw member from further moving for valve closing over the predetermined distance. This makes it possible to inhibit the excessive pushing of the closure member to the valve seat. As a result, either or both of the valve seat and the closure member can be prevented from making plastic deformation, which enables the stop valve to keep a good shut-off efficiency.
In the event that extra-tightening is required for any reason, the rotation actuating portion advances the extra-tightening bolt in the direction for valve closing. Then the thus resulting thrust of the extra-tightening bolt moves the intermediate transmission member in the direction for valve closing. Then the thus moved intermediate transmission member strongly moves the clos
Kaminaga Koichi
Miyata Kazuyuki
Miyazaki Koji
Bacon & Thomas PLLC
Bonderer D A
Kabushiki Kaisha Neriki
Shaver Kevin
LandOfFree
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