TUBE-FASTENING STRUCTURE
TECHNICAL FIELD
[0001]
The present invention relates to a tube-fastening structure for retaining, with a
clip, an elastically deformable tube body such as a hose or a tube to a joint.
BACKGROUND ART
[0002]
As the tube-fastening structure of this type, there has been a tube-fastening
structure in which a circular tightening part capable of tightening a hose from the outer
circumference and an L-shaped hook extending from an axial direction end portion of
the circular tightening part in an axial direction and extending in a circumferential
direction are integrally provided in a clip that radially contracts and tightens, from the
. outer circumference, the hose fit on one end portion of a pipe, an L-shaped cutout is
provided in a flare nut provided in the pipe, and the L-shaped hook is inserted into the
L-shaped cutout in the axial direction and then rotated in the circumferential direction,
whereby the L-shaped hook and the L-shaped cutout engage with each other immovably
in the axial direction (see, for example, Patent Document 1).
There has also been a tube-fastening structure including a.clamp obtained by
bending a long belt-like plate material in a C shape, an engaging part (an engaging hole,
a projected rib, and a recessed groove) formed adjacent to the clamp, and an engaged
part (an engaging protrusion, a recessed groove, and a projecting rib) provided adjacent
to the distal end of a hose on the outer circumferential surface of a pipe into which the
hose is inserted, the engaging part of the clamp being engaged in the engaged part of the
pipe from a radial direction outer side, whereby the engaging part and the engaged part
concave/convex-fit in the radial direction of the hose (see, for example, Patent
Document 2).
CITATION LIST
PATENT DOCUMENTS
[0003]
Patent Document 1: Japanese Patent Application Laid-OpenNo. 2010-169175
Patent Document 2: Japanese Patent Application Laid-Open No. 2006-57798
SUMMARY OF THE INVENTION

TECHNICAL PROBLEM
[0004]
In the first place, a tube body such as a hose or a tube having flexibility formed
of an elastic material such as synthetic resin or rubber has a characteristic that a
dimension error easily occurs in an inner diameter and an outer diameter and thickness
during manufacturing, a characteristic that, when the tube body is tightened from the
outer circumference by a clip or the like, the elastic material in a tightened place is
compression-deformed and the clip or the like bites into the tube body, and the elastic
material compression-deformed by the biting escapes to a place adjacent to the
tightened place and swells and the tube body is deformed, a characteristic that the
thickness decreases according to use for a long period and the tube body is radially
contracted and deformed, and a characteristic that the tube body is easily ruptured by
slight scratching on the outer surface.
However, in such a conventional tube-fastening structure, in the case of Patent
Document 1, since the L-shaped hook and the L-shaped cutout are engaged rotatably in
the circumferential direction, when the hose rotates and twists during use, the L-shaped
hook shifts in position in the circumferential direction together with the hose and the L-
shaped hook is easily disengaged from the L-shaped cutout.
In particular, when rotational movement of the L-shaped hook in the
circumferential direction by an operator is insufficient and the L-shaped hook is not
completely engaged with the L-shaped cutout, the L-shaped hook more easily slips off
the L-shaped cutout. There is a problem in that, in this state, when the hose is pulled,
the hose slips off the pipe together with the clip and slipping-off strength is deteriorated.
In the case of Patent Document 2, even if the clamp bites into the outer
circumferential surface of the hose according to the tightening by the clamp or the
clamp is about to be further radially contracted and deformed according to radial
contraction and deformation due to aged deterioration of the hose, in the structure, the
engaging part is supported by the engaged part and hardly moves in the radial direction
inner side. Therefore, the clamp cannot be smoothly radially contracted and deformed.
Consequently, a gap is formed between the outer circumferential surface of the hose and
the inner circumferential surface of the clamp and a tightening force decreases.
In particular, when a hose having an outer diameter smaller than a standard size
is used because of a manufacturing error, a gap more easily occurs between the outer
circumferential surface of the hose and the inner circumferential surface of the clamp.
There is a problem in that, in this state, when the hose is pulled, the hose slips off
between the clamp and the pipe and slipping-off strength decreases.

Further, in the case of Patent Document 2, there is also a problem in that, when
the elastic material equivalent to the biting into the outer circumferential surface of the
hose according to the tightening by the clamp escapes to the place adjacent to the
tightened place and swells and the hose is deformed, the entire clamp inclines and the
engaging part easily slips off the engaged part.
[0005]
The present invention has been devised to cope with such problems and it is an
object of the present invention to, for example, reliably retain a tube body with a simple
structure irrespective of radial contraction and deformation of the tube body while
preventing scratches on the outer surface of the tube body.
SOLUTION TO PROBLEM
[0006]
In order to attain such an object, the present invention provides a tube-fastening
structure including: a nipple inserted into a tube body which is elastically deformable; a
clip body elastically deformable in a radial direction in which the tube body is held
between the clip body and the nipple and tightened; an operation part for elastic
deformation provided in the clip body; and a hook provided in the clip body to project.
The nipple includes: an insertion part inserted into the tube body; a locking flange
provided at an end of the insertion part; and an engaging groove provided on the side
opposite to the insertion part across the locking flange. The hook includes a flexed part
that climbs over die locking flange in an axial direction according to radial direction
deformation of the clip body. The distal end face of the flexed part is disposed on an
axial direction extended line of the inner circumferential surface of the clip body, and
disposed to be opposed to the locking flange and the engaging groove in the radial
direction across a space part.
ADVANTAGEOUS EFFECTS OF THE INVENTION
[0007]
In the present invention having the characteristic explained above, even if the
clip body is moved along the outer surface of the tube body into which the nipple is
inserted, the distal end face of the flexed part does not collide with the outer surface of
the tube body. While being kept radially expanded and deformed by the operation part,
the clip body is moved toward the locking flange of the nipple and, after the flexed part
of the hook climbs over the locking flange in the axial direction, the clip body is
released from the radial expansion by the operation part. As a result, the clip body is

elastically and radially contracted- and deformed, and the distal end face of the flexed
part enters the engaging groove of the nipple through the use of the radial contraction
and deformation. At the same time, the flexed part engages with the locking flange in
the axial direction to be immovable. Thereafter, even if the tube body is radially
contracted and deformed according to biting of the clip body into the outer surface of
the tube body and aged deterioration, the flexed part moves in the radial direction inner
side along the locking flange and an engaged state of the flexed part and the locking
flange is maintained.
Therefore, it is possible to reliably retain the tube body with a simple structure
irrespective of the radial contraction and deformation of the tube body while preventing
scratches on the outer surface of the tube body.
As a result, compared with the conventional tube-fastening structure in which
the L-shaped hook and the L-shaped cutout are engaged rotatably in the circumferential
direction and the conventional tube-fastening structure in which, even if the clamp is
about to be radially contracted and deformed according to the radial contraction and
deformation of the hose, the engaging part is supported by the engaged part and hardly
moves in the radial direction inner side and, when the place adjacent to the tightened
place on the outer circumferential surface of the hose swells and the hose is deformed
according to the tightening by the clamp, the clamp inclines and the engaging part easily
slips off the engaged part, it is possible to maintain excellent slipping-off strength over a
long period and prevent an accident due to slip-off of the tube body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008]
Fig. 1 is an explanatory diagram showing the overall configuration of a tube-
fastening structure according to an embodiment of the present invention, wherein (a) is
a front view, (b) is a sectional side view taken along line (1B)-(1B) of Fig. 1(a), and (c)
is a longitudinal sectional front view taken along line (1C)-(1C) of Fig. 1(b).
Fig. 2 is a perspective view of a disassembled state, wherein (a) is an overall
perspective view, (b) is a perspective view of a clip viewed from the opposite direction,
(c) is a perspective view showing a radially expanded state of the clip, and (d) is a
perspective view of the clip viewed from the opposite direction in the radially expanded
state.
Fig. 3 is a perspective view and a side view showing a process for connecting a
tube body to a nipple, wherein (a) is a perspective view before insertion of the nipple
. into the tube body, (b) is a side view of the same state, (c) is a perspective view after the

insertion of the nipple into the rube body, (d) is a side view of the same state, (e) is a
perspective view after rotation of the clip, and (f) is a side view of the same state.
Fig. 4 is an enlarged perspective view showing of a modification of the clip.
Fig. 5 is an enlarged perspective view of another modification of the clip.
Fig. 6 is a longitudinal sectional front view showing a modification of the
nipple.
Fig. 7 is a longitudinal sectional front view showing another modification of
the nipple.
DESCRIPTIONS OF EMBODIMENTS
[0009]
An embodiment of the present invention is explained in detail below with
reference to the drawings.
In a tube-fastening structure according to the embodiment of the present
invention, as shown in Fig. 1 to Fig. 5, a nipple 1 of a joint B is inserted into a
connection end portion of a tube body A and then the connection end portion of the tube
body A is retained to the nipple 1 by a clip C.
That is, after the joint B is inserted into the tube body A, the tube body A is
fastened (coupled) to the nipple 1 by the clip C to be immovable in a slipping-off
direction F of the tube body A.
More specifically, the tube-fastening structure according to the embodiment of
the present invention includes, as main components, the nipple 1 of the joint B inserted
into the tube body A which is elastically deformable, a clip body 2 of the clip C
elastically deformable in a radial direction in which the tube body A is held between the
clip body 2 and the nipple 1 and tightened, operation parts 3 for elastic deformation
provided in the clip body 2, and a hook 4 provided in the clip body 2 to project.
[0010]
The tube body A is, for example, a hose or a tube formed of a soft material
having flexibility such as soft synthetic resin like vinyl chloride or silicon rubber or
other rubber. The tube body A is desirably a tube body, an outer surface Al and an inner
surface A2 of which are flat.
As a specific example of the tube body A, as shown in Fig. 1 to Fig. 3, a hose
of a single-layer structure is used.
As other examples, although not shown in the figures, it is also possible to use,
for example, a stacked hose (a blade hose) in which a plurality or a singularity of
synthetic resin blade (a reinforced string) is embedded in a spiral shape as an

intermediate layer between an outer layer and an inner layer, which are transparent or
non-transparent, a spiral reinforced hose (a Vohran hose) in which a belt-like reinforcing
material, for example, rectangular in section made of synthetic resin or metal and a
linear reinforcing material, for example, circular in section are wound in a spiral shape
and integrated as an intermediate layer, and a spiral reinforced hose in which a metal
line material or a hard synthetic resin material is embedded in a spiral shape.
[0011]
The joint B includes the nipple 1 on one end side in an axial direction thereof.
The nipple 1 is formed of an un-deformable rigid material such as metal like
brass or hard synthetic resin in a substantially cylindrical shape having an outer
diameter substantially the same as the inner diameter of the tube body A or formed in a
thin cylindrical shape by pressing or otherwise molding a plate material made of a
deformable hard material such as stainless steel.
Further, the nipple 1 includes, on the outer circumferential surface, an insertion
part 11 inserted into a connecting end portion of the tube body A, a locking flange 12
formed at an end of the insertion part 11, and an engaging groove 13 provided on the
side opposite to the insertion part 11 in the axial direction (an inserting direction G
opposite to a slipping-off direction F) across the locking flange 12.
The locking flange 12 is desirably formed in an annular shape projecting in the
radial direction on the outer circumferential surface of the nipple 1 and includes a
notched part 12a through which a flexed part 41 (a second flange side surface 12d) of
the hook 4 explained below can pass in the axial direction. As shown in Fig. 1 to Fig. 3,
the notched part 12a is desirably formed in a concave shape such that the bottom surface
thereof is disposed shallower than the. depth of the inner bottom surface of the engaging
groove 13. As another example, although not shown in the figures, it is also possible to
form the notched part 12a in the concave shape such that the bottom surface is still
shallower than the illustrated example or not to form the notched part 12a in the
concave shape..
Further, it is desirable to form one or more (a singularity or a plurality of)
notched parts 12a in a concave shape partially in the circumferential direction of the
locking flange 12.
The engaging groove 13 is formed in the circumferential direction to be
adjacent to the locking flange 12 and is set to be deeper than a projection amount of the
locking flange 12 and shallower than the outer circumferential surface of the nipple 1.
[0012]
The clip C includes a clip body 2 disposed to cover the outer circumference of

the connection end portion of the tube body A, the operation parts 3 for elastically
deforming the clip body 2, and at least one or more (a singularity or a plurality of)
hooks 4 provided at an axial direction one end of the clip body 2.
The clip body 2 is formed by bending, in an annular shape, a strip member
made of metal excellent in elastic resiliency such as spring steel or other elastic
materials. The clip body 2 has an inner circumferential surface 2a elastically
deformable in the radial direction.
The operation parts 3 are provided at circumferential direction both ends or one
end of the strip member bent in the annular shape functioning as the clip body 2. The
operation parts 3 are moved in the circumferential direction resisting a spring force of
the clip body 2, whereby the annular strip member is elastically deformed in the radial
direction to expand the inner diameter of the clip body 2.
In the example shown in Fig. 1 to Fig. 3, the clip body 2 and the hook 4 are
integrally formed and the hook 4 is also made elastically deformable.
As another example, although not shown in the figure, it is also possible to
separately form the clip body 2 and the hook 4 and integrate the clip body 2 and the
hook 4 through welding or adhesion thereof. In this case, the hook 4 is also desirably
formed of an elastically deformable material.
[0013]
The inner diameter of the clip body 2 is set to be substantially the same as or
slightly smaller than the outer diameter of the tube body A in an initial state in which the
nipple 1 is not inserted as shown in Figs. 2(a) and 2(b) and Figs. 3(a) and 3(b) at radial
contraction time when the operation parts 3 are not operated to move. As shown in
Figs. 1(a) to 1(c) and Figs. 3(e) and 3(f), in a connected state in which the clip body 2 is
disposed to cover the outer circumference of the tube body A into which the nipple 1 is
inserted, the inner diameter is set to be smaller than the outer diameter of the tube body
A. The connection end portion of the tube body A is held in the radial direction between
the clip body 2 and the insertion part 11 and elastically tightened.
At radial expansion time when the operation parts 3 are moved in the
circumferential direction, as shown in Figs. 2(c) and 2(d) and Figs. 3(c) and 3(d), the
inner diameter of the clip body 2 is set to be larger than not only the outer diameter of
the tube body A in the initial state in which the nipple 1 is not inserted but also the outer
diameter of the tube body A into which the nipple 1 is inserted. Consequently, a gap is
formed between the inner circumferential surface 2a of the clip body 2 and the outer
surface A1 of the tube body A into which the nipple 1 is inserted. It is possible to freely
move the clip body 2 of the clip C in the axial direction and the circumferential

direction with respect to the outer surface Al of the tube body A into which the nipple 1
is inserted.
[0014]
As a specific example of the clip C, as shown in Fig. 1 to Fig. 5, the clip C
includes a pair of operation parts 3 respectively bent and formed at circumferential
direction both ends of the strip member bent in the annular shape functioning as the clip
body 2, a through-hole 2b formed from a circumferential direction one end portion of
the strip member to one operation part ,3, and a movable part 2c formed contiguously
from the operation part 3 to be movable in the circumferential direction in the through-
hole 2b.
At the radial contraction time by non-operation of the operation parts 3, as
shown in Figs. 2(a) and 2(b) and Figs. 3(a) and 3(b), the through-hole 2b and the
movable part 2c are disposed to overlap each other in the axial direction such that the
operation parts 3 separate from each other. As shown in Figs. 2(c) and 2(d) and Fig.
3(c) and 3(d), the two operation parts 3 are pinched and moved to come close to each
other by a tool, fingers, or the like, whereby the movable part 2c smoothly moves in the
through-hole 2b. An overlapping amount on the through-hole 2b decreases and the
through-hole 2b is radially expanded and deformed. By releasing the pinch of the
operation parts 3 from the radially expanded state, the through-hole 2b is radially
contracted deformed by a spring force of the clip body 2.
As another example, although not shown in the figures, it is also possible to
form the operation parts 3 only at a longitudinal direction one end of the strip member
functioning as the clip body 2 and change the shapes of the through-hole 2b, the
movable part 2c, and the operation parts 3.
[0015]
A singularity or a plurality of hooks 4 are integrally formed or integrally
fixedly attached to project in the axial direction and the radial direction in a part of the
circumferential direction at an axial direction one end of the clip body 2. The hook 4
includes a flexed part 41 extending in the radial direction along the locking flange 12 of
the nipple 1 and capable of climbing over the locking flange 12 in the axial direction
according to the radial direction deformation of the clip body 2.
The flexed part 41 includes a first protrusion 41a extending to the radial
direction outer side along a first flange side surface 12b of the locking flange 12, a
cylindrical part 41b extending from the distal end of the first protrusion 41a in the axial
direction along a flange outer surface 12c of the locking flange 12, and a second
protrusion 41c extending from the distal end of the cylindrical part 41b to the radial

direction inner side toward the engaging groove 13 of the nipple 1 along the second
flange side surface 12d of the locking flange 12.
The second protrusion 41c of the flexed part 41 is set to climb over the locking
flange 12 in the axial direction according to the movement of the tube body A, into
which the nipple 1 is inserted because of the radial expansion and deformation of the
clip body 2, with respect to the outer surface Al and enter the engaging groove 13
according to radial contraction and deformation of the clip body 2 thereafter.
[0016]
Further, the second protrusion 41c of the flexed part 41 has a distal end face
41d opposed to the inner bottom surface of the engaging groove 13 of the nipple 1 in the
radial direction. The distal end face 4 Id of the second protrusion 41c is disposed to be
opposed to the locking flange 12 and the engaging groove 13 across a space part S in
the radial direction in a state in which the second protrusion 41c enters the engaging
groove 13 of the nipple 1 according to the radial contraction and deformation of the clip
body 2.
In the examples shown in Figs. 2(a) to 2(d), the distal end face 41d of the
second protrusion 41c is disposed in substantially the same shape as the inner
circumferential surface 2a of the clip body 2 in the axial direction.
As another example, although not shown in the figure, it is also possible to
dispose the distal end face 41d of the second protrusion 41c in a concave shape further
to the radial direction outer side than an axial direction extended line of the inner
circumferential surface 2a of the clip body 2.
The space part S includes a first space SI sectioned and formed between the
cylindrical part 41b of the flexed part 41 and the flange outer surface 12c of the locking
flange 12 and a second space S2 sectioned and formed between the second protrusion
41c of the flexed part 41 and the inner bottom surface of the engaging groove 13. When
the tube body A tightened between the clip body 2 and the insertion part 11 of the nipple
1 is radially contracted and deformed, the cylindrical part 41b of the flexed part 41
comes close to the flange outer surface 12c of the locking flange 12 in association with
the radial contraction and deformation. At the same time, the second protrusion 41c of
the flexed part 41 comes close to the inner bottom surface of the engaging groove 13.
The second protrusion 41c of the flexed part 41 can.be moved to the.radial direction
inner side along the second flange side surface 12d of the locking flange 12.
It is desirable that, in the flexed part 41, a space for rotation 41e wider in the
axial direction than the locking flange 12 of the nipple 1 is formed between the first
protrusion 41a and the second protrusion 41c and the second protrusion 41c is rotated

along the second flange side surface 12d of the locking flange 12 and the engaging
groove 13.
[0017]
A method of connecting the tube body A to the joint B in the tube-fastening
structure according to the embodiment of the present invention is explained according to
process order.
First, in an initial state shown in Fig. 3(a), the tube body A is inserted through
the clip body 2 of the clip C and then the nipple 1 of the joint B is inserted into the
connection end portion of the tube body A. In the example shown in Fig. 3(a), the
connection end portion of the tube body A is pushed in an inserting direction G against
the nipple 1 of the joint B.
In the initial state, as shown in Fig. 3(b), the operation part 3 of the clip C is not
operated to move, the clip body 2 is radially contracted. In this case, when the inner
diameter of the clip body 2 is set substantially the same as the outer diameter of the tube
body A, the inner circumferential surface 2a of the clip body 2 slides along the outer
surface A1 of the tube body A. Therefore, it is possible to smoothly insert the clip C.
When the inner diameter of the clip body 2 is set to be slightly smaller than the
outer diameter of the tube body A, the operation parts 3 of the clip C are moved close to
the clip body 2 and the clip body 2 is radially expanded and deformed. Then, gaps are
formed between the inner circumferential surface 2a of the clip body 2 and the distal
end face 41d of the flexed part 41 and the outer surface Al of the tube body A.
Therefore, it is possible to smoothly insert the clip C.
[0018]
Subsequently, as shown in Figs. 3(c) and 3(d), while the clip body 2 is kept
radially expanded and deformed by the operation parts 3 of the clip C, the clip body 2
and the hook 4 are moved in the inserting direction G to come close to the locking
flange 12 of the nipple 1. Consequently, the flexed part 41 (the second protrusion 41c)
of the hook 4 climbs over the locking flange 12 in the axial direction.
In the example shown in the figures, the distal end face 41 d of the second
protrusion 41c disposed substantially in the same shape in the axial direction as the
inner circumferential surface 2a of the clip body 2 is moved in the inserting direction G.
Consequently,, the distal end face 41d smoothly passes in the axial direction without
coming into contact with the bottom surfaces of the notched parts 12a and easily climbs
over the locking flange 12.
As another example, although not shown in the figure, it is also possible to
partially elastically deform and move, in the inserting direction G, the entire hook 4 or

at least the flexed part 41 (the second protrusion 41c) to make a change such that the
distal end face 41d of the second protrusion 41c climbs over the bottom surfaces of the
notched parts 12a formed in a concave shape shallower than the illustrated example and
the flexed part 41 (the second protrusion 41c) of the hook 4 climbs over the locking
flange 12 in the axial direction.
Note that, if a deformation amount of the clip body and the hook 4 is large, the
notched parts 12a do not have to be formed in a concave shape.
[0019]
After the flexed part 41 of the hook 4 climbs over the locking flange 12 in the
inserting direction G according to the movement, as shown in Figs. 3(e) and 3(f), the
operation parts 3 are moved oppositely and the radial expansion and deformation of the
clip body 2 is released. Then, the clip body 2 is elastically and radially contracted and
deformed and nips and tightens the connection end portion of the tube body A between
the clip body 2 and the nipple 1 of the joint B.
At the same time, the distal end face 4Id of the flexed part 41 enters the
engaging groove 13 of the nipple 1.
Consequently, the second protrusion 41c of the flexed part 41 engages with the
second flange side surface 12d of the locking flange 12 in the slipping-off direction F to
be immovable. Therefore, the connection end portion of the tube body A is retained to
the nipple 1 of the joint B by the clip C. The tube body A is reliably connected to the
joint B.
[0020]
With the tube-fastening structure according to the embodiment of the present
invention explained above, in a preparation process for setting the clip C to the
connection end portion of the tube body A into which the nipple 1 of the joint B is
inserted, even if the clip body 2 is moved in the inserting direction G along the outer
surface Al of the tube body A, the distal end face 41d of the flexed part 41 does not
collide with the outer surface Al of the tube body A. Therefore, it is possible to prevent
scratches on the outer surface A1 of the tube body A.
Subsequently, while the clip body 2 is kept radially expanded and deformed by
the operation parts 3, the clip body 2 is moved toward the locking flange 12 of the
nipple 1. After the flexed part 41 of the hook 4 climbs over the locking flange 12 in the
inserting direction G, the clip body 2 is released from the radial expansion by the
operation parts 3. As a result, the clip body 2 is elastically and radially contracted and
deformed, and the distal end face 41d of the flexed part 41 enters the engaging groove
13 of the nipple 1 through the use of the radial contraction and deformation. At the

same time, (the second protrusion 41c of) the flexed part 41 engages with (the second
flange side surface 12d of) the locking flange 12 in the axial direction to be immovable.
After the connection end portion of the tube body A is connected and fixed to
the joint B by the clip C, even if the connection end portion of the tube body A is
radially contracted and deformed according to biting of the clip body 2 into the outer
surface Al of the tube body A and aged deterioration, the second protrusion 41c of the
flexed part 41 moves in the radial direction inner side along the second flange side
surface 12d of the locking flange 12 and an engaged state of the flexed part 41 and the
locking flange 12 is maintained. '
Consequently, it is possible to reliably retain the tube body A irrespective of the
radial contraction and deformation in the connection end portion of the tube body A.
Therefore, it is possible to maintain excellent slipping-off strength over a long
period and prevent an accident due to slip-off of the tube body A.
[0021]
In particular, as in the illustrated example, when the locking flange 12 of the
nipple 1 includes the notched parts 12a through which the flexed part 41 of the hook 4
can pass in the axial direction and the flexed part 41 includes the space for rotation 41e
wider than the locking flange 12, as shown in Fig. 3(c), the flexed part 41 (the second
protrusion 41c) of the hook 4 is caused to pass in the axial direction along the notched
parts 12a of the locking flange 12, whereby the flexed part 41 (the second protrusion
41c) climbs over the locking flange 12 in the axial direction.
Further, when the notched parts 12a afe formed in a concave shape shallower
than the depth of the engaging groove 13, even if the operation parts 3 of the clip C are
not forced to move close to the clip body 2 to radially expand the clip body 2 more than
necessary, the flexed part 41 (the second protrusion 41c) of the hook 4 climbs over the
locking flange 12. When the pinch of the operation parts 3 is released, even if the hook
4 is not rotated along the locking flange 12 (the second flange side surface 12d)
according to the rotation operation of the clip body 2, the distal end face 41d of the
flexed part 41 enters the engaging groove 13 of the nipple 1. The flexed part 41 (the
second protrusion 41c) engages with the locking flange 12 (the second flange side
surface 12d) in the axial direction to be immovable.
Therefore, even if a radial expansion and deformation amount of the clip body
2 by the operation parts 3 is small, it is possible to reliably retain the clip body 2 and
engage the clip body 2 with the locking flange 12.
Thereafter, as shown in Fig. 3(e), it is desirable to further rotate the clip body 2
to rotate the hook 4 along the locking flange 12 (the second flange side surface 12d) and

move the flexed part 41 (the second protrusion 41c) to a place where the notched parts
12a are absent in the locking flange 12 (the second flange side surface 12d).
In this case, the flexed part 41 (the second protrusion 41c) is more reliably
engaged with the locking flange 12 (the second flange side surface 12d) in the axial
direction. Integrity can be improved.
When the hook 4 is configured such that the distal end face 41d of the second
protrusion 41c is disposed in a concave shape further on the radial direction outer side
than the axial direction extended line of the inner circumferential surface 2a of the clip
body 2, the distal end face 41d of the second protrusion 41c and the outer surface Al of
the tube body A are further separated.
Consequently, it is possible to reliably prevent scratches on the outer surface
Al of the tube body A due to the distal end face 41d of the second protrusion 41c.
Note that, when the hook 4 is configured such that the flexed part 41 (the
second protrusion 41c) of the hook 4 climbs over the locking flange 12 according to
elastic deformation of the entire or a part of the hook 4, as shown in Fig. 3(e), it is
unnecessary to further rotate the clip body 2.
Example 1
[0022]
Examples of the present invention are explained with reference to the drawings.
In an Example 1, as shown in Fig. 1 to Fig. 3, an annular recessed part 11a that
fits in the radial direction with the tube body A tightened by the clip body 2 is provided
in the circumferential direction in the insertion part 11 of the nipple 1, in a position
opposed in the radial direction to, across the tube body A, an end portion 2d of the clip
body 2, which is positioned in the axial direction with respect to the locking flange 12
by the hook 4.
[0023]
In the example shown in Fig. 1 to Fig. 3, a plurality of annular recessed parts
11a are formed in the insertion part 11. Any one of the annular recessed part 11a and
the end portion 2d disposed on the side opposite to the hook 4 in the slipping-off
direction F of the tube body A in the clip body 2 are disposed to be opposed to each
other in theradial direction.
More specifically, a plurality of (a pair of) recessed grooves lib are formed as
the annular recessed part 11a to be spaced apart at a predetermined interval from each
other in the axial direction. An edge is disposed as the end portion 2d of the clip body 2
to be opposed in the radial direction to a first step part lie disposed in the most forward

position in the slipping-off direction F of the tube body A among the recessed grooves
11b.
Further, the first step part 11c disposed in the most forward position in the
slipping-off direction F of the tube body A among the recessed grooves 11b is erected
substantially perpendicularly in the radial direction from the inner bottom surfaces of
the recessed grooves 11b. Second step parts 11d respectively disposed in the direction
opposite to the slipping-off direction F in the recessed grooves 11b, that is, in the
inserting direction G of the tube body A incline to be gradually radially expanded from
the inner bottom surfaces of the recessed grooves 11b toward the inserting direction G.
Consequently, the tube body A is tightened toward the insertion part 11 by the
clip body 2 including the movable part 2c and is elastically deformed along the annular
recessed part 11a. Therefore, the inner surface A2 of the tube body A engages with the
annular recessed part 11a. The end portion 2d of the clip body 2 disposed on the side
opposite to the hook 4 and the first step part 11e of the recessed grooves 11b engage in
the axial direction.
As another example, although not shown in the figure, it is also possible to
form one or three or more annular recessed parts 1 la in the insertion part 11 and arrange
step parts of the annular recessed parts 11a to be opposed to the end portion 2d of the
clip body 2 in the radial direction.
[0024]
With the tube-fastening structure according to the Example 1 of the present
invention, the clip body 2 positioned in the axial direction with respect to the locking
flange 12 of the nipple 1 by the hook 4 is elastically and radially contracted and
deformed, whereby the end portion 2d of the clip body 2 holds the tube body A and fits
with the annular recessed part 11a (the first step part 11c) of the insertion part 11 in the
radial direction. Therefore, frictional resistance in the axial direction of the inner
surface A2 of the tube body A against the insertion part 11 of the nipple 1 further
increases.
Therefore, it is possible to make the tube body A less easily slip off the nipple
1.
As a result, there is an advantage that it is possible to attain further
improvement of slipping-off strength of the tube body A against the nipple 1.
[0025]
In particular, in the example shown in Fig. 1 to Fig. 3, an engaging hole 2e is
pierced and drilled separately from the through-hole 2b in the strip member functioning
as the clip body 2.

The engaging hole 2e is disposed such that a part of a hole edge thereof is
opposed to, across the tube body A, a first step part 11c erected substantially
perpendicularly in the radial direction from the inner bottom surface of a recessed
groove 11b.
The shape of the engaging hole 2e is not limited to an illustrated example and
can be changed.
Consequently, the hole edge of the engaging hole 2e bites into, through
tightening of the clip body 2, the outer surface Al of the tube body A, into which the
nipple 1 is inserted, shown in Figs. 1(a) to 1(c) and Figs. 3(e) and 3(f) and increases the
frictional resistance of the outer surface Al and the clip body 2. At the same time, a part
of the hole edge of the engaging hole 2e fit with the first step part 11c of the annular
recessed part 11a in the radial direction across the tube body A. Therefore, the frictional
resistance in the axial direction of the inner surface A2 of the tube body A against the
insertion part 11 of the nipple 1 further increases.
As another example, as shown in Fig. 4, the engaging hole 2e does not have to
be provided.
[0026]
Further, in the example shown in Fig. 1 to Fig. 3, in the nipple 1, further on the
axial direction other end side than the engaging groove 13, a tool engaging part 14 with
which a tool (not shown in the figure) such as a spanner or a wrench engages and a
connecting part 15 for connection to another tube connection port (not shown in the
figure) formed by another apparatus or anther tube body are respectively integrally
formed.
As the tool engaging part 14, a hexagonal nut is formed.
In the connecting part 15, when an inner thread is cut on the inner
circumferential surface of a tube connection port in another apparatus, another tube
body, or the like connected to the joint B, an outer thread corresponding to the inner
thread is cut. When an outer thread is cut on the outer circumferential surface of the
tube connection port, an inner thread corresponding to the outer thread is cut. In the
illustrated example, an outer thread is cut as the connecting part 15.
As another example, although not shown in the figure, it is also possible to
separately form the nipple 1. and the joint B and detachably attach the nipple 1 and the
joint B.
[0027]
Further, it is also possible to connect the nipple 1 of the joint B and another
apparatus or another tube body with the connecting part 15 to allow the nipple 1 and the

other apparatus or the other tube body to electrically communicate with each other.
In particular, when the joint B, the clip body 2 of the clip C, and the hook 4 are
formed of a conductive material such as metal, in a connection state of the tube body A
and the joint B, the hook 4 of the clip body 2 in contact with the outer surface Al of the
tube body A is in contact with the locking flange 12 of the nipple 1. Therefore, the outer
surface Al of the tube body A is in an electrically communicating state with the nipple 1
or another apparatus or another tube body via the clip body 2.
In addition, when a conductive part or an outermost layer made of a conductive
material is provided on the outer surface A1 of the tube body A in order to remove static
electricity generated by transfer of fluid flowing through the tube body A, the static
electricity generated by the transfer of the fluid can be earthed to the nipple 1 side from
the outer surface Al of the tube body A through the clip body 2. Consequently, it is
possible to provide the tube-fastening structure excellent in safety.
[0028]
When the connecting part 15 is connected to another tube connection port by a
thread, depending on a screwing state of the connecting part 15, it is likely that the
notched parts 12a of the locking flange 12 are disposed at an angle at which the notched
parts 12a are less easily seen from the operator.
Therefore, in the illustrated example, the plurality of (the pair of) notched parts
12a are respectively formed at every predetermined interval in the circumferential
direction in the locking flange 12.
As another example, although not shown in the figure, it is also possible to
form three or more notched parts 12a respectively at every predetermined interval in the
circumferential direction in the locking flange 12.
Example 2
[0029]
An Example 2 is different from the Example 1 shown in Fig. 1 to Fig. 4 in a
configuration in which, as shown in Fig. 5, a plurality of hooks 4 are respectively
provided at every predetermined interval in the circumferential direction at the axial
direction one end of the clip body 2 and, in the locking flange 12, the notched parts 12a
• equal to or more than the number of hooks 4 are respectively formed at every
predetermined interval in the circumferential direction. Otherwise, the Example 2 is the
same as the Example 1 shown in Fig. 1 to Fig. 4.
[0030]
In an example shown in Fig. 5, at an axial direction one end of the clip body 2,

a pair of hooks 4 is formed at every predetermined interval in the circumferential
direction to be opposed to the pair of notched part 12a formed in the locking flange 12.
As another example, although not shown in the figure, it is also possible to
form, at the axial direction one end of the clip body 2, three or more hooks 4
respectively at every predetermined interval in the circumferential direction.
[0031]
With the tube-fastening structure according to the Example 2 of the present
invention explained above, the clip body 2 engages with the locking flange 12 of the
nipple 1 in the circumferential direction with a plurality of hooks 4 in a well-balanced
state. It is possible to prevent backlash of the clip body 2 with respect to the locking
flange 12 of the nipple 1.
Consequently, there is an advantage that the tightening by the clip body 2 is
more stabilized and excellent slipping-off strength can be maintained for a longer period
than in the Example 1 shown in Fig. 1 to 4 and it is possible to prevent an accident due
to slip-off of the tube body A.
Note that, in the example shown in Fig. 5, the engaging hole 2e is pierced
through and drilled in the strip member functioning as the clip body 2. However, not
only this, but, as in the example shown in Fig. 4, the engaging hole 2e does not have to
be provided.
Example 3
[0032]
An Example 3 is different from the Example 1 shown in Fig. 1 to Fig. 4 and the
Example 2 shown in Fig. 5 in a configuration in which, as shown in Fig. 6 and Fig. 7, in
the insertion part 11 of the nipple 1, an annular seal member 16 that comes into press
contact with, in the radial direction, the inner surface A2 of the tube body A tightened
by the clip body 2 is provided in a position opposed to the clip body 2, which is
positioned in the axial direction by the hook 4 with respect to the locking flange 12,
across the tube body A in the radial direction. Otherwise, the Example 3 is the same as
the Example 1 shown in Fig. 1 to Fig. 4 and the Example 2 shown in Fig. 5.
[0033]
In an example shown in Fig-. 6, an annular projected part lie is formed in the
insertion part 11. The annular seal member 16 is embedded in the annular projected part
lie such that the outer circumferential end of the annular seal member 16 projects from
the outer circumferential surface of the insertion part 11. The disposition positions of
the annular projected part lie and the annular seal member 16 are aligned to overlap, in

the radial direction, the strip member of the clip body 2 positioned in the axial direction
by the hook 4 with respect to the locking flange 12.
More specifically, in the annular projected part 11e, a locking groove 11f is
annularly recessed. By fitting the annular seal member 16 in the inside of the locking
groove 11f, the outer circumferential end of the annular seal member 16 is held
immovably in the axial direction to partially project from the outer circumferential
surface of the annular projected part 11e.
As the annular seal member 16, it is desirable to use a gasket 16a formed of an
elastically deformable O-ring or the like made of an elastic body such as rubber. The
gasket 16a is disposed to be opposed to the movable part 2c, which is disposed in the
axial direction substantially center part of the clip body 2, in the radial direction across
the tube body A.
[0034]
In an example shown in Fig. 7, a plurality of (a pair of) annular seal members
16 are embedded in a plurality of annular recessed parts 11a formed in the insertion part
11 such that the external circumferential ends of the respective annular seal members 16
project from the inner bottom surfaces of the recessed grooves 11b. The disposition
positions of the annular projected part 11e and the annular seal members 16 are aligned
such that the annular projected part 11e and the annular seal members 16 overlap, in the
radial direction, the strip member of the clip body 2 positioned in the axial direction by
the hook 4 with respect to the locking flange 12.
More specifically, in the recessed grooves 11b of the annular recessed parts
11a, the locking grooves llf are recessed in an annular shape. The annular seal
members 16 are fit in the insides of the locking grooves 11f, whereby the outer
circumferential ends of the annular seal members 16 are held immovably in the axial
direction to partially project from the inner bottom surfaces of the recessed grooves 11b.
As the annular seal members 16, it is desirable to use gaskets 16b formed of
elastically deformable O-rings or the like made of an elastic body such as rubber. A
plurality of (a pair of) gaskets 16b are disposed to be opposed to axial direction both
end parts of the clip body 2 in the. radial direction across the tube body A.
[0035]
With the tube-fastening structure according to Example 3 of the present
invention, the clip body 2 positioned in the axial direction by the hook 4 with respect to
the locking flange 12 of the nipple 1 is elastically and radially contracted and deformed,
whereby the inner surface A2 of the tube body A is strongly pressed against the annular
seal member 16 (the outer circumferential ends of the gaskets 16a and 16b) and the

inner surface A2 of the tube body A and the annular seal members 16 strongly adhere to
each other.
Therefore, it is possible to reliably seal the inner surface A2 of the tube body A
and the insertion part 11 of the nipple 1 with adequate tightening of the clip body 2.
As a result, simply by adequately tightening the clip body 2, it is possible to
further prevent a leak from the tube body A than the Example 1 shown in Fig. 1 to Fig. 4
and the Example 2 shown in Fig. 5. In particular, even if the inner surface A2 of the
tube body A is deteriorated in elastic resiliency because of permanent strain through use
for a long period like a hose made of synthetic resin, since the annular seal member 16
continues to be strongly compression-bonded to the inner surface A2, a gap is not
formed. It is possible to maintain pipe connection without a leak for a long period.
Consequently, there is an advantage that even the tube body A having
flexibility like the hose made of synthetic resin can be used as a pipe material in a place
left as connected for a long period such as an indoor pipe of a house.
Note that, in the example shown in Fig. 6, one annular seal member 16 is
disposed to be opposed to the axial direction substantially center part of the clip body 2
in the radial direction. In the example shown in Fig. 7, a plurality of (a pair of) annular
seal members 16 are disposed to be opposed to the axial direction both end parts of the
clip body 2. However, not only this, but it is also possible to dispose the annular seal
members 16 to be opposed to places other than the axial direction substantially center
part and the axial direction both end parts of the clip body 2 or dispose three or more
annular seal members 16 or change the number of annular seal members 16.
REFERENCE SIGNS LIST
[0036]
A Tube body
A2 Inner surface
1 Nipple
11 Insertion part
11a Annular recessed part
12 Locking flange
12a Notched part
13 Engaging groove
2 Clip body
2a Inner circumferential surface

3 Operation parts
4 Hook
41 Flexed part
41d Distal end face
41e Space for rotation
16 Annular seal member
S Space part

CLAIMS
Claim 1
A tube-fastening structure comprising:
a nipple inserted into a tube body which is elastically deformable;
a clip body elastically deformable in a radial direction in which said tube body
is held between the clip body and said nipple and tightened;
an operation part for elastic deformation provided in said clip body; and
a hook provided in said clip body to project, wherein
said nipple includes: ran insertion part inserted into said tube body; a locking
flange provided at an end of said insertion part; and an engaging groove provided on the
side opposite to said insertion part across said locking flange,
said hook includes a flexed part that climbs over said locking flange in an axial
direction according to radial direction deformation of said clip body, and
a distal end face of said flexed part is disposed on an axial direction extended
line of an inner circumferential surface of said clip body, and disposed to be opposed to
said locking flange and said engaging groove in the radial direction across a space part.
Claim 2
The tube-fastening structure according to claim 1, wherein said locking flange
of said nipple includes a notched part through which said flexed part of said hook can
pass in the axial direction, and said flexed part has a space for rotation wider than said
locking flange.
Claim 3
The tube-fastening structure according to claim 1 or 2, wherein an annular
recessed part that fits in the radial direction with said tube body tightened by said clip
body is provided in the circumferential direction in said insertion part of said nipple, in
a position opposed in the radial direction to, across said tube body, an end portion of
said clip body positioned in the axial direction with respect to said locking flange by
said hook.
Claim 4
The tube-fastening structure according to claim 1, 2, or 3, wherein an annular
seal member that is in press contact with, in the radial direction, an inner surface of the

tube body tightened by said clip body is provided in said insertion part of said nipple, in
a position opposed in the radial direction to, across said tube body, said clip body
positioned in the axial direction with respect to said locking flange by said hook.