EP2295161A1

EP2295161A1 - Pipe clamp device

Info

Publication number: EP2295161A1
Application number: EP08873819A
Authority: EP
Inventors: Yasushi Niwayama; Yasuji Kitaura; Yasukazu Nakamura; Tadahiro Higaki; Tadashi Nishimoto
Original assignee: Rex Industries Co Ltd
Current assignee: Rex Industries Co Ltd
Priority date: 2008-04-10
Filing date: 2008-10-31
Publication date: 2011-03-16
Also published as: JP5448360B2; TWI451919B; TW200942343A; EP2295161A4; JP2009248176A; WO2009125512A1

Abstract

As illustrated in Fig. 3, a mating surface of a lower clamping member (1b) is provided with protrusions (11) and a mating surface of an upper clamping member (1a) is provided with recesses (12) that accommodate the respective protrusions (11), wherein the protrusions (11) have surfaces (13a) perpendicular to an axis of a pipe material (4) and, wherein the surfaces (13a) are provided to be flush with a surface (13b) of the lower liner (3b) in the lower clamping member (1b) that abuts against a step forming surface (2c) so that the step forming surface (2c) of the upper liner (3a) and the step forming surface (2c) of the lower liner (3b) abut against the same surface due to a pressing force of a flare forming process when clamping the pipe, so that formation of a bump in a pipe axial direction of the upper and lower liners (3a, 3b) can be prevented.

Description

TECHNICAL FIELD

The present invention relates to a pipe clamping device that is used for a flare forming processing device for forming a flare at an end of a pipe and, more specifically, it relates to a pipe clamping device that is required to form, by using a flare forming tool, a flare shaped portion provided at an end of a pipe material when connecting the pipe material used as a refrigerant pipe of an air conditioner, and the like.

BACKGROUND ART

Conventionally, in order to form a flare by conically widening an end of a pipe material (mainly, a copper material), a flare forming processing device that consists of a pipe clamping device and a manual or electric-powered flare forming tool is used. As illustrated in Fig. 1, while an eccentric cone 5 of the flare forming tool is pressed against an end of a pipe material 4 clamped by the pipe clamping device, eccentric cone 5 is rotated, so as to form the flare of pipe material 4. A rotation center of eccentric cone 5 is inclined with respect to an axis line of a main spindle, so that an apex of eccentric center 5 is always located on the axis line of the main spindle, even when the main spindle rotates.
An example of a conventional pipe clamping device is illustrated in Fig. 10. The pipe clamping device has two halves of a clamp 1 that are openably and closeably coupled with each other by a fulcrum 7 at one end. Clamp 1 consists of an upper clamping member 1a and a lower clamping member 1b. A clamping bolt is axially rotatably supported at the other end of upper clamping member 1a, and a link is axially rotatably supported at the other end of lower clamping member 1b. During the flare forming process of pipe material 4, the clamping bolt is screwed into an unillustrated clamping nut by rotating a knob 8, so that upper clamping member 1a and lower clamping member 1b clamp pipe material 4.
Then, after the flare forming process of pipe material 4 is completed, knob 8 is loosened and tilted outward as illustrated by chain double-dashed lines to open upper clamping member 1a and lower clamping member 1b. Reference numeral 19 denotes a stopper for axially positioning the pipe material that can be withdrawn from the end position of the pipe after the positioning.
Further, as illustrated in Figs. 10 and 11, upper and lower liners 3a and 3b having a pinching section 2a for pinching pipe material 4 on an inside thereof and a conical surface 2b for forming the flare on an end face thereof are removably and integrally secured to upper and lower clamping members 1a and 1b described above, respectively, by screws 14.
In order to perform the flare forming process at the end of the pipe, the end of pipe material 4 where the flare is to be formed is inserted into clamp 1 and pressed against stopper 19. Knob 8 is rotated to clamp upper and lower clamping members 1a and 1b, so that pipe material 4 is secured. In case of the power tool, the motor is rotated to push the main spindle forward by a feed screw shaft while the main spindle is also rotated. As a result, eccentric cone 5 is eccentrically rotated to apply the pushing force to the end of pipe material 4 so that the flare is formed at the end of pipe material 4.
At this time, it is desirable that the pair of upper and lower liners 3a and 3b are secured to clamp 1 so as to not form a bump therebetween in an axial direction and a center deviation along a division surface 6 in a direction perpendicular to the axial direction, so that end face angle portions of upper and lower liners 3a and 3b form a perfect conical surface 2b during the flare forming process.
However, there is a problem in that the conventional pipe clamping device described above is not provided with a mechanism for adequately securing clamp 1 in the pipe axial direction when clamping the pipe and, as a result, bump T (Fig. 13A) in the axial direction described above is formed in the upper and lower liners 3a and 3b due to the pressing force during the flare formation process. Further, there is also the center deviation described above in which and lower liners 3a and 3b are deviated from each other in the radial direction of pipe material 4.
The center deviation described above is defined by a center-to-center distance R between fulcrum 7 and half-circular arcs of upper and lower clamping members 1a and 1b. However, the center deviation is may not be formed because there is a gap between a shaft diameter and a hole diameter of fulcrum 7 and upper and lower liners 3a and 3b are clamped along pipe material 4. Thus, formation of the bump is a more serious problem that frequently occurs. If the bump is formed, the shape of the flare becomes defective as illustrated in Figs. 13A and 13B.
As described above, the bump between upper and lower liners 3a and 3b is directly reflected on the shape of the flare of pipe material 4. The formation of the bump up to a point does not affect gas leakage. However, even when the gas leakage occurs due to the other causes such as insufficiently tightened joints or other constructional problems, the defected shape of the flare may be suspected as the cause of the gas leakage. Consequently, in order to also find out the true cause of the gas leakage, there is a need for a pipe clamping device that does not form the bump between upper and lower liners 3a and 3b.
Conventionally, in order to address the problem of the formation of the bump, as illustrated in Figs. 11 and 12, upper clamping member 1a is provided with a projecting piece 9 and lower clamping member 1b is provided with a fitting portion for projecting piece 9 mentioned above, so that, when clamping pipe material 4, projecting piece 9 fits into fitting portion 10 to prevent the formation of the bump in the pipe axial direction.
However, there is a gap (P and Q in Fig. 12) between projecting piece 9 and fitting portion 10 for preventing interference upon fitting. Because upper and lower liners 3a and 3b receive the pressing force in a direction of arrow F in Fig. 12 during the flare forming process, upper clamping member 1a is deviated along the pipe in the direction of arrow F by a length of gap P of fitting portion 10. Even though the dimensions of projecting piece 9 and fitting portion 10 are defined to minimize gap P as much as possible, the bump of about 0.2 mm is formed due to accumulated dimensional tolerances. Consequently, it is difficult to completely eliminate the bump.
Japanese Unexamined Patent Publications Nos. 2003-126917 , 7-96331 and 7-185675 describe the conventional pipe clamping device.

SUMMARY OF INVENTION

In view of the above problem of the conventional art, it is an object of the present invention to provide a pipe clamping device and a flare forming processing device using the same in which a bump in a pipe axial direction is not formed in upper and lower liners due to a pressing force when a flare forming process is performed, so that the flare forming process can always be performed satisfactorily.
According to the present invention, there is provided a pipe clamping device for processing an end of a pipe, comprising a pair of clamping members that are openably and closeably coupled with each other by a fulcrum at one end and to which halved upper and lower liners are attached respectively, wherein a pair of the halved upper and lower liners forms a substantially cylindrical shape to clamp an entire outer circumferential surface of the end of the pipe material, wherein each of said upper and lower liners has a semicylindrical inner surface, a conical inclined surface that is provided at one end face continuously to such inner surface for processing the end of the pipe material, and an outer circumferential surface where a step is formed by a step forming surface perpendicular to an axis of the cylinder, and the clamping members are clamped in a state in which the inner surfaces abut against the outer circumferential surface of the end of the pipe material and an end face of the pipe material is aligned with an outer end position of the inclined surface, so that the liners clamp the pipe material, wherein the clamping members face each other at mating surfaces when clamping the pipe, wherein the mating surface of the lower clamping member is provided with protrusions and the mating surface of the upper clamping member is provided with recesses that accommodate the respective protrusions, and the protrusions have surfaces perpendicular to the axis of the pipe material, wherein such surfaces are provided to be flush with a surface of the lower liner in the lower clamping member that abuts against the step forming surface so that the step forming surface of said upper liner and the step forming surface of the lower liner abut against the same surface when clamping the pipe.
Further, according to the present invention, there is also provided a pipe clamping device, wherein, in addition to said protrusions and the recesses, or in place of such protrusions and recesses, one of abutment surfaces between the upper and lower liners when clamping the pipe is provided with pins and the other is provided with pin holes coaxial with the pins, wherein the pins and the pin holes have respective chamfered portions for avoiding mutual interference.
Furthermore, according to the present invention, there is also provided a pipe clamping device wherein said pin holes have a diameter larger than that of the pins and they are arranged eccentrically with respect to the pins.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is an assembly cross-sectional view of a first embodiment of a pipe clamping device and a flare forming processing device of the present invention;
Fig. 2 is an assembly schematic diagram illustrating the first embodiment of the pipe clamping device of the present invention;
Fig. 3 is a cross-sectional view taken along the line A-A of Fig. 2;
Fig. 4 is a cross-sectional view taken along the line B-B of Fig. 2;
Fig. 5 is a perspective view of a pair of clamping members of this embodiment when viewed from a side opposite to a flare processing surface;
Fig. 6 is perspective view of the pair of clamping members of this embodiment when viewed from a side of the flare processing surface;
Fig. 7A is a diagram describing a second embodiment of a pipe clamping device of the present invention that illustrates a cross-sectional view on a division surface of a lower liner;
Fig. 7B is a diagram describing the second embodiment of the pipe clamping device of the present invention that illustrates an assembly cross-sectional view of a pair of upper and lower liners taken along the line C-C of Fig. 7A;
Fig. 8 is a partial enlarged view of Fig. 7B;
Fig. 9 is a cross-sectional view on a division surface of a lower liner illustrating another embodiment of the present invention;
Fig. 10 is an assembly schematic view illustrating an example of a conventional pipe clamping device;
Fig. 11 is a cross-sectional view taken along the line D-D of Fig. 10;
Fig. 12 is a cross-sectional view taken along the line E-E of Fig. 10;
Fig. 13A is a diagram schematically illustrating conditions of a pipe and liners when a defective flare is formed due to a bump; and
Fig. 13B is a diagram schematically illustrating the condition of the pipe when the defective flare is formed due to the bump.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a first embodiment of a pipe clamping device of the present invention will be described with reference to the drawings.
Since a pipe clamping device of this embodiment illustrated in Figs. 1 to 4 has a clamping mechanism for a flare forming process configured substantially identically to that of a pipe clamping device of the conventional art described in Figs. 10 to 12, configuration differences between the both pipe clamping devices will be described. Like elements are designated by like reference numerals. Further, terms such as "upper" or "lower" appended to clamping members, liners, etc., are merely intended to clarify the positional relationships between the elements. These terms do not represent spatial positions in actual layout and do not limit the mounting conditions of this device.
Both pipe clamping devices similarly consist of a pair of clamping members 1a and 1b to which halved upper and lower liners 3a and 3b are attached, respectively. A pair of liners 3a and 3b forms a substantially cylindrical shape and clamps an entire outer circumferential surface of an end of a pipe material 4. However, the pipe clamping device of this embodiment differs from the pipe clamping device of the conventional art in that, among surfaces 6a and 6b of the pair of clamping members 1a and 1b, respectively, that are mating with each other when clamping the pipe, mating surface 6b of lower clamping member 1b is provided with protrusions 11 and mating surface 6a of upper clamping member 1a is provided with recesses 12 that accommodate respective protrusions 11 mentioned above when clamping the pipe.
Thus, in the configuration described above of this embodiment, each protrusion 11 is provided by extending a portion of lower clamping member 1b. Then, a surface 13a of each protrusion 11 that is perpendicular to an axis of the pipe material is provided to be flush with a surface 13b abutting against a step forming surface 2c of lower liner 3b in lower clamping member 1b. Positional relationships between protrusions 11, recesses 12, surfaces 13a and liner abutment surfaces 13b are illustrated in Figs. 5 and 6.
In the configuration described above, when the flare forming process is performed at the end of the pipe, pipe material 4 is clamped by upper and lower liners 3a and 3b. While an eccentric cone 5 rotates about its eccentric axis and, further, the eccentric axis rotates about a central axis, eccentric cone 5 is pressed in the direction of the central axis, so that a conical inclined surface of eccentric cone 5 rotates along the outer circumferential surface of the end of pipe material 4 and applies an axial pressing force for processing to the end of the pipe. Due to this pressing force, step forming surface 2c of upper liner 3a and step forming surface 2c of lower liner 3b abut against surface 13a and abutment surface 13b that are flush therewith and, as a result, no bump in the direction of the pipe axis is formed in upper and lower liners 3a and 3b.
As described above, in the first embodiment, protrusions 11 are formed at the portions of mating surface 6b of lower clamping member 1b and surfaces 13a of protrusions 11 abut against step forming surface 2c of upper liner 3a. Surfaces 13a described above are arranged to be flush with surfaces 13b that abut against lower liner 3b of lower clamping member 1b. As a result, during the flare formation, both upper and lower liners 3a and 3b abut against surfaces 13a and 13b that are flush with each other, so that the formation of the bump can be prevented.
Next, a second embodiment will be described.
In this embodiment, in order to prevent deviation of upper and lower liners 3a and 3b, each of upper and lower liners 3a and 3b is provided with respective pins 15 and pin holes 16. As illustrated in Figs. 7A and 7B, two pairs, in total, of pins 15 and pin holes 16 are provided in a lower surface of upper liner 3a and a upper surface of lower liner 3b one by one.
A diameter gap between pin 15 and pin hole 16 can be set to be 0.1 mm or less. Consequently, the bump dimension can be restricted to 0.1 mm or less or, in other words, the formation of the bump can be substantially prevented. Further, as illustrated in Fig. 8, an outer circumferential portion of an end face of each pin 15 and an edge of each pin hole 16 are provided with chamfered portions 17, so that the outer circumferential portion of the end face of each pin 15 does not interfere with the edge of each pin hole 16 to easily fit therein when clamping the pipe. In this embodiment, protrusions 11 and recesses 12 described above are replaced by the two pairs of pins 15 and pin holes 16. However, pins 15 and pin holes 16 may be provided in addition to the protrusions 11 and recesses 12 described above.
This embodiment illustrates an example in which pins 15 and pin holes 16 are arranged so that each pin 15 and respective pin hole 16 are coaxial with each other. However, in another embodiment, as illustrated in Fig. 9, a diameter of a hole 18 may be larger than a diameter of respective pin 15, so that pin 15 may be inserted into hole 18 with a dimensional deviation of S when clamping the pipe. It eases restrictions on accuracy of chamfered portions 17 of pin 15 for fitting thereof.
In the embodiment in which hole 18 is formed with the deviation as described above, an inner wall of one hole 18 in the direction of pipe axis is disposed to substantially touch an outer circumferential portion of pin 15, so that the formation of the bump in the direction of the pipe axis in upper and lower liners 3a and 3b can be prevented.
In Fig. 9, only one of two pin junctions is formed with the deviation. However, both pin junctions may be formed with the deviation.
As described above, the pipe clamping device and the flare forming processing device using the same according to the present invention can prevent the formation of the bump in the upper and lower liners during the flare forming process and improve reliability of the flare forming process of the pipe material.

Claims

A pipe clamping device for processing an end of a pipe, comprising a pair of clamping members that are openably and closeably coupled with each other by a fulcrum at one end and to which halved upper and lower liners are attached respectively, wherein a pair of the halved upper and lower liners forms a substantially cylindrical shape to clamp an entire outer circumferential surface of an end of a pipe material,
wherein each of said upper and lower liners has a semicylindrical inner surface, a conical inclined surface that is provided at one end face continuously to said inner surface for processing the end of said pipe material, and an outer circumferential surface where a step is formed by a step forming surface perpendicular to an axis of the cylinder, and
said clamping members are clamped in a state in which said inner surfaces abut against the outer circumferential surface of the end of said pipe material and an end face of said pipe material is aligned with an outer end position of said inclined surface, so that said liners clamp said pipe material,
characterized in that said clamping members face each other at mating surfaces when clamping said pipe, wherein said mating surface of the lower clamping member is provided with protrusions and the mating surface of the upper clamping member is provided with recesses that accommodate said respective protrusions, and
said protrusions have surfaces perpendicular to the axis of said pipe material, wherein said surfaces are provided to be flush with a surface of said lower liner in said lower clamping member that abuts against said step forming surface so that said step forming surface of said upper liner and said step forming surface of said lower liner abut against the same surface when clamping said pipe.
A pipe clamping device according to claim 1, characterized in that, in addition to said protrusions and said recesses, or in place of such protrusions and recesses, one of abutment surfaces between said upper and lower liners when clamping said pipe is provided with pins and the other is provided with pin holes coaxial with the pins, wherein said pins and said pin holes have respective chamfered portions for avoiding mutual interference.
A pipe clamping device according to claim 2, characterized in that said pin holes have a diameter larger than that of said pins and they are arranged eccentrically with respect to said pins.