Pipe joints or couplings – Packed – Externally with clamp
Reexamination Certificate
1999-09-09
2001-03-20
Browne, Lynne H. (Department: 3629)
Pipe joints or couplings
Packed
Externally with clamp
C285S379000, C285S374000, C285S348000
Reexamination Certificate
active
06203073
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a metal or resin tube joint used for water pipes and the like.
2. Description of the Related Art
FIG. 5
shows one example of a tube joint for jointing ends of axially opposed metal or resin tubes
1
,
1
such that extending and contracting function and flexible function are provided. The tube joint includes a joint body
2
and a pair of push rings
3
and
3
, and they are fastened by fastening means
4
which are T-shaped bolts and nuts. The joint body
2
includes opposed flange-like projections
2
a
and
2
a
, and a cylindrical barrel portion
2
b
which is integrally formed such as to swell between the projections
2
a
,
2
a
. Each of the projections
2
a
is provided at its inner periphery with a receiving port
2
c
whose diameter becomes wider toward its end. The push ring
3
also includes a projection
3
a
, the joint body
2
is located at the outer periphery between the joint tubes
1
and
1
while leaving a circumferential gap, and the push rings
3
,
3
are disposed at the opposite ends, and the ends are fastened by the fastening tools
4
. By fastening using the fastening tools
4
, a rubber packing
5
set between the joint body
2
and each of the push rings
3
is pushed by surfaces of the push rings
3
and connected to the receiving port
2
c
in wedge form, and is also contacted to an outer peripheral surface of the joint tube
1
under pressure. With this, watertightness is established so that liquid flowing through the joint tubes
1
,
1
should not leak outside.
As shown in
FIG. 5
also, the conventional tube joint has a structure that if the fastening tools
4
are fastening, the rubber packing
5
can freely be fastened. Therefore, even if a tolerance fastening torque is indicated, the fastening state varies depending upon operators, and torque can not be controlled.
The cross section of the rubber packing
5
(JIS K6353; A type) shown in
FIG. 5
is tapered, and any portions thereof are relatively hard, and homogeneous having the same resilience. Therefore, strong pressing force can not be obtained, and the sealing ability is not sufficient. As a rubber packing which can be used in the tube joint shown in
FIG. 5
, there exists one having soft portion (JIS K6353; K type), but a volume of the rubber packing occupied by the soft portion is smaller than that occupied by the hard portion, and there is a room for improvement of the resiliently deforming and sealing abilities.
SUMMARY OF THE INVENTION
The present invention has been accomplished to overcome the above-described conventional problems, and it is the first object of the invention to provide a tube joint in which the operation can easily be controlled by always obtaining a constant fastening force irrespective of magnitude of the fastening force, and the sealing ability is always reliably obtained constantly. It is another object to provide a tube joint in which the sealing ability is stronger than that of the prior art so that a constant sealing ability or greater can be reliably obtained.
To solve the above problems, a tube joint of the present invention comprises: a pushing ring provided at its outer periphery with a projection and fitted to an outer periphery of one end of a joint tube; a tube or a joint body provided at is side opposed to the pushing ring with a projection opposed to the projection of the pushing ring, the tube or the joint body having a receiving portion which is widened toward the pushing ring and the tube or the joint body being fitted to an outer periphery of the joint tube with a peripheral gap left therebetween; a fastening tool capable of moving the pushing ring in a direction of the tube or the joint body; a packing provided between inner and outer side of the tube or the joint body and the joint tube, and fitted through the receiving portion by its own resilient deformation by operation of the fastening tool; and a spacer inserted between the pushing ring and the tube or the joint body to limit a distance between the pushing ring and the tube or the joint body to a constant value.
With this structure, since the spacer for limiting the distance between the pushing ring and the tube or the joint body is inserted between the pushing ring and the tube or the joint body, the packing can always obtain a constant fastening force irrespective of the magnitude of the fastening force and therefore, the packing which is prone to be unstable due to the resilient deformation can always be fastened constantly, the operation is facilitated, the operation can easily be controlled, and since the packing may be fastened to the utmost, the sealing ability can always be obtained reliably and constantly.
It is preferable that the spacer is an independent ring provided between the pushing ring and the tube or the joint body.
With this structure, since the spacer is the independent ring, i.e., a spacer ring provided between the pushing ring and the tube or the joint body, the packing can be pushed by the entire ring uniformly as compared with a case in which the packing is pushed directly by the pushing ring whose portion in the circumferential direction can fasten using split mold, and the sealing ability is enhanced, which is convenient.
Further, a tube joint of the invention comprises: a pushing ring provided at its outer periphery with a projection and fitted to an outer periphery of one end of a joint tube; a tube or a joint body provided at is side opposed to the pushing ring with a projection opposed to the projection of the pushing ring, the tube or the joint body having a receiving port which is widened toward the pushing ring and the tube or the joint body being fitted to an outer periphery of the joint tube with a peripheral gap left therebetween; a fastening tool capable of moving the pushing ring in a direction of the tube or the joint body; a packing provided between inner and outer side of the tube or the joint body and the joint tube, and fitted through the receiving portion by its own resilient deformation by operation of the fastening tool; and a spacer inserted between the pushing ring and the tube or the joint body to limit a distance between the pushing ring and the tube or the joint body to a constant value, and the spacer being deformed by fastening operation of the fastening tool, thereby bringing the pushing ring and the tube or the joint body into abutment against each other.
With this structure also, the spacer is deformed by the fastening operation by the fastening tool, the pushing ring and the tube or the joint body abut against each other, the packing can always obtain a constant fastening force irrespective of the magnitude of the fastening force and therefore, the packing which is prone to be unstable due to the resilient deformation can always be fastened constantly, the operation is facilitated, the operation can easily be controlled, and since the packing may be fastened to the utmost, the sealing ability can always be obtained reliably and constantly.
It is preferable that the spacer is an independent resin ring provided between the pushing ring and the tube or the joint body, and is provided with an alignment projection.
With this structure, the packing can be pushed by the entire ring uniformly as compared with a case in which the packing is pushed directly by the pushing ring whose portion in the circumferential direction can fasten using split mold, and the sealing ability is enhanced. In addition to this, when the fastening tool is fastened, since it is made of resin, it is deformed easily, the spacer should not deviated laterally by the operation of the alignment projection and therefore, the packing should not be deformed, these can be disposed easily, and the operation is facilitated, which is convenient.
Further, a tube joint of the invention comprises: a pushing ring provided at its outer periphery with a projection and fitted to an outer periphery of one end of a joint tube; a tube or a joint body provided at is side opposed to the pushing ring w
Sakai Kosuke
Sato Taichi
Shirakawa Koichi
Browne Lynne H.
Knobbe Martens Olson & Bear LLP
Malcolm Tomlyne
Waterworks Technology Development Organization Co., Ltd.
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