Pipe joints or couplings – Packed – Wedge
Reexamination Certificate
1999-06-16
2001-01-16
Luu, Teri Pham (Department: 3627)
Pipe joints or couplings
Packed
Wedge
C285S039000, C285S308000
Reexamination Certificate
active
06174002
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tube coupling for connecting tubes.
2. Description of the Related Art
Conventionally known tube couplings are disclosed in the Official Gazette of the Japanese Laid-Open Publication Application No.Hei
8-326976,
for example. As shown in FIG.
6
and
FIG. 7
, a conventional tube coupling comprises a coupling body
10
, a separation prevention ring
20
which is disposed within the coupling body
10
, and a release ring
30
which pushes the separation prevention ring
20
while moving in a predetermined range from the coupling body
10
.
The separation prevention ring
20
is intervened between a back ring
13
and a guide ring
14
, which are disposed within the coupling body
10
so to be prevented from separating from the coupling body
10
. A seal ring
40
is disposed in the coupling body
10
to make sealing secure by tightly adhering to the outside wall of the tube body
1
. And, a shoulder portion
11
, which an inside end portion of the tube body
1
contacts, is formed in the coupling body
10
.
As shown in FIG.
6
and
FIG. 7
, the separation prevention ring
20
has outer edges
22
that intervene between the back ring
13
and the guide ring
14
and inner edges
21
which bites into the tube body
1
and has a zigzagged annular shape which is of many radial grooves
23
alternately formed by the inner edges
21
and the outer edges
22
.
The outer peripheral edges of the separation prevention ring
20
, namely the outer edges
22
, have a fixed width and substantially the same total length as that of the inner edges
21
. When the tube body
1
is inserted into the separation prevention ring
20
, the inner edges
21
bite into the outer wall of the tube body
1
to prevent the tube body
1
from falling out of the coupling body
10
.
But, in the separation prevention ring
20
shown in
FIG. 7
, since the total length of the outer edges
22
fixed by the back ring
13
and the guide ring
14
is substantially the same as that of the inner edges
21
which bite into the tube body
1
, if the tube body
1
fixed by the inner edges
21
is forcedly pulled, a force applied to the outer edges
22
deforms the original shape of the outer edges
22
and damages the outer edges
22
. Accordingly, the separation prevention ring
20
is separated from the back ring
13
and the guide ring
14
and may be separated from the tube coupling
10
as a result.
Since it is configured so that a large number of inner edges
21
bite into the tube body
1
at the same time, when the tube body
1
is slantly pulled from the coupling body
10
, a part of the inner edges
21
can no longer properly bite into the outer wall of the tube body
1
, causing the tube body
1
to fall out of the coupling body
10
.
SUMMARY OF THE INVENTION
The present invention was achieved in order to solve the problems described above. And it is an object of the present invention to provide a tube coupling which can prevent a tube body from pulling out by securely biting into a coupling body in the tube body and can prevent a separation prevention ring, which bites into the tube body, from being separated even if the tube body is pulled by a strong force.
It is also an object of the present invention to provide a method for producing a separation prevention ring for such tube coupling.
In order to achieve the above object, the tube coupling according to the present invention comprises a coupling body, a separation prevention ring which is disposed in the coupling body to bite into the outer wall of a tube body fitted into the coupling body so to prevent the tube body from falling out, and a release ring which is disposed in the coupling body so to be movable in an axial direction within a predetermined range and releases the biting into the tube body by the separation prevention ring by pushing the separation prevention ring, wherein the separation prevention ring comprises a ring portion which contacts a back ring disposed in the coupling body; pushing portions which are radially formed in a large number within the ring portion, and have grooves which have a circular shape and extends from the outside of the ring portion to the inside, and are pushed by the inside end of the release ring; and projections which are respectively formed at tips of the pushing portions and pulled out of the outer wall of the tube body when they are pushed by the inside end of the release ring in a state fitted in the outer wall of the tube body.
The tube coupling according to the present invention has an advantage that the outer edges are held between the back ring and the guide ring and not separated even if the tube body fixed by the inner edges is pulled by a strong force, because the total length of the outer edges positioned between the back ring and the guide ring is formed to be longer than the total length of the inner edges biting into the coupling body.
Since it is configured that a plurality of projections are simultaneously pressed so to bite into the outer wall of the tube body, even if the tube body is slantly pulled from the coupling body, the tube coupling has an advantage that the projections fitting into the outer wall of the tube body makes it hard for the tube body to fall out of the tube coupling.
Meanwhile, since a portion for joining the pushing portion with the ring portion of the separation prevention ring has a small width, there is an advantage that the tube body can be inserted into the tube coupling by a small force, and the tube body is readily pulled out of the tube coupling just by slightly pushing the release ring.
In order to achieve the above-described object, the first method for producing the separation prevention ring is comprised by a step of forming a photosensitive layer by applying a photoresistant to a predetermined metal plate; a step of forming patterns of an annular ring portion and a plurality of circular pushing portions and projections protruded from the tips of the respective pushing portions in a radial pattern within the ring portion by enlightening the photosensitive layer; and a step of etching with an etching solution along the patterns of the metal plate, on which the patterns of the ring portion, the pushing portions, and the projections are formed.
The second method for producing the separation prevention ring is comprised by a step of forming to have the shapes of the inside diameter and the outside diameter of the separation prevention ring by stamping.
REFERENCES:
patent: 3837687 (1974-09-01), Leonard
patent: 4084843 (1978-04-01), Gassert
patent: 4586734 (1986-05-01), Grenier
patent: 4593943 (1986-06-01), Hama et al.
patent: 4667988 (1987-05-01), Maier et al.
patent: 4747626 (1988-05-01), Hama et al.
patent: 5692784 (1997-12-01), Hama et al.
patent: 5779284 (1998-07-01), Guest
patent: 8-326976 (1998-07-01), None
Gilster, Peter S. Greensfelder, Hemker & Gale, P.C.
Kuroda Precision Industries Ltd.
Luu Teri Pham
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