JP2001030348A - Resin pipe bending apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin pipe bending apparatus capable of applying bending processing while keeping a cross-sectional shape. SOLUTION: In a resin pipe bending apparatus, two places along the longitudinal direction of a resin pipe P are received by two receiving members 1 and the central position between the received two places of the resin pipe is pressed by a pressure member 2. In this case, receiving groove parts M1 and a pressure groove part M2 having an almost semicircular cross-sectional shape in order to hold the resin pipe P are separately provided to the receiving members and the pressure member 12 and the curvature of the almost semicircular cross-section related to the receiving groove parts M1 is formed so as to be larger than the curvature of the outer periphery of the resin pipe P on a view in the cross-sectional direction of the resin pipe and the curvature R2 of the almost semicircular cross section related to the pressure groove part M2 is formed so as to be smaller than the curvature of the outer periphery of the resin pipe P on a view in the cross-sectional direction vertical to the longitudinal direction X of the resin pipe P.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin pipe bending apparatus for receiving two points along a longitudinal direction of a resin pipe with two receiving members and pressing a central position of the received two points with a pressing member. .

[0002]

2. Description of the Related Art Conventionally, when bending a resin pipe, there has been a type in which two locations are respectively received by two receiving members, and a central position thereof is pressed by a pressing member. However, the conventional bending apparatus is capable of bending not only a resin pipe but also a metal pipe, and is useful in that various pipe members can be bent.

[0003]

However, for example, when a metal pipe or a resin pipe having a circular cross section is bent, a portion outside the bending direction with respect to the axial center of the pipe member receives a tensile force, and the axial center of the pipe member is subjected to a tensile force. On the other hand, since the inner part in the bending direction receives a compressive force, the cross-sectional shape of the bent pipe member must be flattened by being shrunk and deformed in the pressing direction of the pipe member. For this reason, in the conventional bending device, the curvature of the cross section of the receiving groove formed in the receiving member is formed to be larger than the curvature of the outer diameter of the cross section of the pipe member to be bent. In other words, especially when bending a metal tube,
This is because the flattened metal pipe may bite into the receiving groove, and if the biting occurs, not only the metal pipe cannot be removed from the receiving groove but also the surface of the metal pipe is damaged, which is not preferable. . As a result of using such a bending device, the same deformation occurs even when the resin pipe is bent, and there has been an inconvenience such that the cross section of the bent portion is flattened and the cross sectional area is reduced.

An object of the present invention is to provide a resin pipe bending apparatus capable of solving the above-mentioned drawbacks of the prior art and performing a bending process while maintaining a sectional shape.

[0005]

The features of the present invention for achieving this object will be described with reference to the example shown in FIG.

(Structure 1) In the resin pipe bending apparatus of the present invention, the receiving member 1 and the pressing member 2 have a substantially semicircular cross-sectional shape for holding the resin pipe P. The receiving groove M1 and the pressing groove M2 are separately provided, and the curvature R1 of the substantially semicircular cross section of the receiving groove M1 is provided.
Is defined by the outer peripheral curvature R of the resin pipe P in the sectional direction.
P, and the curvature R2 of the substantially semicircular cross section of the pressing groove M2 is larger than the outer curvature RP of the resin pipe P in a cross-sectional direction perpendicular to the longitudinal direction X of the resin pipe P. It is characterized by its small size. (Operation and Effect) In the device of the present invention, the curvature of the cross section of the pressing groove portion is formed smaller than the outer peripheral curvature of the cross section of the resin tube. Can be reliably prevented. By maintaining the cross-sectional shape of the resin tube in good condition, it is possible to obtain a bent portion of the resin tube that does not have a cross-sectional defect in the resin tube and does not increase the flow resistance of the fluid that flows inside. Further, since the curvature of the cross section of the receiving groove is formed larger than the outer curvature of the resin tube, the resin tube does not bite into the receiving member. Therefore, when the pressing member is pulled back, the resin tube is easily separated from the receiving member. As a result, since no external force for eliminating the bending deformation applied to the resin tube acts on the resin tube, the resin tube can be bent accurately and efficiently.

(Structure 2) In the resin pipe bending apparatus of the present invention, the pressing groove portion M2 can be configured to be able to abut on the maximum outer diameter portion of the resin pipe P. (Operation / Effect) As in the present configuration, if the pressing groove portion can contact the maximum outer diameter portion of the resin tube, the cross-sectional shape of the resin tube is prevented from being flattened when the resin tube is bent. be able to. For this reason, a bent part with a beautiful appearance can be obtained.

[0008] In the description of the means for solving the above problems, reference is made to the drawings and, in order to facilitate comparison with the drawings, the reference numerals are used, but the present invention is limited to the configuration shown in the accompanying drawings. Not something.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. (Outline of Apparatus) A resin pipe bending apparatus according to the present invention is shown in FIG.
(A) As shown in (B), two locations along the longitudinal direction X of the resin pipe P having a substantially cylindrical shape are respectively received by the two receiving members 1, and the center position of the received two locations is the pressing member 2. This is a device for bending the resin pipe P by pressing with. Each part of this device is configured as follows.

(Receiving Member) The two receiving members 1 are provided on one side of the apparatus main body 3 via a support arm 4.
The receiving member 1 is a wheel-shaped member that is rotatable about a rotation axis 5, and is supported by the support arm 4. 2A and 2B show the appearance of the receiving member 1. FIG. An annular receiving groove M1 is formed on the outer peripheral surface of the receiving member 1.
Is formed. The cross-sectional shape of the receiving groove M1 is substantially semicircular. In the present invention, the curvature R1 of the cross section of the receiving groove portion M1 is larger than the curvature RP of the outermost peripheral portion of the cross section of the resin pipe P. This function will be described later. Here, the sectional shape of the receiving groove portion M1 is defined as a plane including the rotation axis 5 and the receiving member 1.
Of the receiving groove portion M1 appearing when the cutting is performed. The curvature R1 of the cross section of the receiving groove portion M1 refers to a radius of the contour having a substantially semicircular shape. The curvature RP of the cross section of the resin pipe P is the radius of the outermost peripheral portion of the substantially circular cross section of the resin pipe P that appears when the resin pipe P is cut along a plane perpendicular to the longitudinal direction X. Say.

(Pressing Member) The pressing member 2 is a member for applying a bending force to the resin pipe P, and is moved toward the center of the two receiving members 1 by a driving mechanism 6 provided in the apparatus main body 3. You can leave. That is, the pressing member 2
Is movable in a direction perpendicular to a plane including both the rotation axes 5 of the two receiving members 1, that is, in the pressing direction Y. The appearance of the pressing member 2 is shown in FIG.

As shown in FIG. 3A, the pressing member 2 has a fan-shaped planar shape when viewed in a direction parallel to the rotation axis 5 of the receiving member 1. And, Fig. 3 (a) (b)
As shown in FIG. 5, a pressing groove M2 similar to that formed in the receiving member 1 is formed on the side surface of the arc-shaped edge. However, unlike the case of the receiving member 1, the curvature R2 of the substantially semicircular cross-section related to the pressing groove portion M2 is formed smaller than the curvature RP of the cross-section related to the resin pipe P. The reason will be described later.

The pressing member 2, unlike the receiving member 1, does not rotate. That is, the resin pipe P subjected to the bending process comes into contact with the distal end portion of the pressing member 2 and then sequentially contacts both ends of the pressing groove portion M2 as the bending increases. Therefore, there is no substantial slippage between the resin pipe P and the pressing groove M2, and there is no need to rotate the receiving member 1 as in the receiving member 1.

The central angle θ of the sector is formed to be tens of degrees larger than the bending angle of the resin pipe P. For example, 25A
When it is desired to bend the resin tube P having a size of 90 degrees, the pressing member 2 having the central angle θ set to 115 degrees is used. this is,
Even when the resin pipe P is deformed at a predetermined angle, when the bending force is released, the resin pipe P returns and deforms by a certain angle, so it is necessary to add the return deformation in advance. is there. Further, as described above, the resin pipe P is 90
When it is desired to bend to a degree, there is no need to perform bending at 115 degrees by using the pressing member 2 having the central angle θ smaller than 115 degrees. If such processing is performed, the resin pipe P is strongly pressed against both ends of the pressing groove M2, and a concave defect is formed on the surface of the resin pipe P, which is not preferable.

The pressing groove M2 is configured to be able to abut the maximum outer diameter portion of the resin pipe P. That is, FIG.
As shown in (b), when the resin pipe P in the middle of bending is viewed along the direction of its axis 7, an imaginary line perpendicular to the pressing direction Y of the pressing member 2 is outside the resin pipe P. Surface 8
Are defined as a first intersection 9a and a second intersection 9b. In the bending device of the present invention, the pressing groove M2 is configured to abut on the first intersection 9a and the second intersection 9b. For example, the cross-sectional shape of the pressing groove M2 is U
It is formed in a U-shape so that it can abut on a substantially half-circumferential portion of the surface of the resin pipe P. Thereby, it is possible to reliably contact the first intersection 9a and the second intersection 9b. These first
The intersection 9a and the second intersection 9b are in the longitudinal direction X of the resin pipe P.
, The pressing groove M2
Will linearly contact the maximum outer diameter portion of the resin pipe P.

Further, as shown in FIG. 3B, the depth D of the pressing groove M2 is set to be larger than the curvature RP of the cross section of the resin pipe P. That is, the pressing groove portion M2 has two parallel surfaces except for the semicircular portion. In this way, by abutting on the maximum outer diameter portion of the resin pipe P, it is possible to prevent the circular cross-sectional shape of the resin pipe P from flattening when bending the resin pipe P, and to make the cross section closer to a perfect circle. A bent portion having a shape can be obtained. As a result,
The resin tube P having few cross-sectional defects can be obtained even at the bent portion, and the resistance of the substance flowing inside can be minimized.

(Bending operation) Here, a specific example of a bending operation for forming a 90-degree bent portion using a polyethylene pipe (PE pipe P1) as the resin pipe P will be described. The PE pipe P
1 uses, for example, a tube of 25A size. in this case,
The tube thickness is 3.4 mm or more.

<Heating> First, a portion of the PE pipe P1 to be bent is locally heated. The heating is
The higher the temperature, the smaller the amount of return after bending. However, since it is necessary that the temperature be such that the PE pipe P1 is not melted, the PE pipe P1 is heated to 110 ° C. here. The heating is performed using various heating devices. For example, although not shown, a heating device having a heating space into which the resin pipe P can be locally inserted can be used.

FIG. 4 shows the relationship between P and the heating temperature.
The relationship between the elapsed time after the bending process was performed to an angle of 105 degrees and the return angle for the E pipe P1 was shown. FIG. 4 shows that the return angle is smaller in the case of heating at 110 ° C. than in the case of heating at 100 ° C. However, 110
Even when heated to ° C., a return of about 23 degrees resulted.

<Press bending> PE pipe P heated to 110 ° C.
1 is set in the bending apparatus. First, the heated portion is set so as to extend over the two receiving members 1. Then, the pressing member 2 is made to protrude from the apparatus main body 3, and the pressing is continued until the PE pipe P1 has an angle of about 115 degrees. At the time of the pressing, for example, it is convenient to prepare a 115-degree gauge so that the end position of the pressing can be easily recognized.
As the gauge, for example, a dedicated gauge may be prepared using a plate member or the like, or a 115 ° line may be drawn on the ground at the work site. P
At the time of pressing, the E pipe P1 contracts and deforms in the pressing direction Y of the pressing member 2 and tends to flatten. However, as shown in FIG. 3B, the flattening of the PE pipe P1 is prevented because the pressing groove M2 restricts the maximum outer diameter portion of the PE pipe P1.

<Cooling / Removal> After the PE pipe P1 is subjected to 115 ° bending deformation, the PE pipe P1 is cooled while maintaining the state. The cooling is performed, for example, with a cloth containing water.
Water cooling is performed by covering the E tube P1. This water cooling is performed for about 10 minutes in the case of a 25A tube. After the cooling is completed, the pressing member 2 is retired, and the PE pipe P1 is moved from the resin pipe bending apparatus.
Remove.

In the resin pipe bending apparatus of the present invention, the pressing groove M
2 is smaller than the curvature RP of the cross section of the PE pipe P1. Therefore, when the pressing member 2 is withdrawn, the PE pipe P1 is held in the pressing groove M2. I will be pulled back. On the other hand, the curvature R1 of the cross section of the receiving groove portion M1 is formed to be larger than the curvature RP of the cross section of the PE pipe P1, and the receiving member 1 and the PE pipe P1 during the application of the bending force. Means that the PE pipe P1 does not bite into the receiving groove M1. In this way, by preventing the PE pipe P1 from biting into the receiving groove M1, the bending deformation once applied to the PE pipe P1 is prevented from being returned again when the pressing member 2 is retired. It is. On the other hand, although the PE pipe P1 is bitten by the pressing groove M2,
Since the PE pipe P1 has a certain degree of elasticity, its removal is easy.

<Modification of PE Pipe> FIG. 5 shows a change in the cross-sectional shape of the PE pipe P1 before and after bending when the resin pipe bending apparatus according to the present invention is used, and a case where the conventional apparatus is used. 3 shows a difference from the state of change in the cross-sectional shape of FIG. Fig. 5 (a)
As shown in FIG. 3, in the case of the present invention, there is almost no change in the lateral dimension, that is, as shown in FIG. 3B, the change in the distance between the first intersection 9a and the second intersection 9b. Similarly, it can be seen that the vertical dimension, that is, the maximum outer diameter in the direction orthogonal to the horizontal dimension, is also reduced by only about 2 mm. In this case, the overall oblateness is about 6% because the external dimension is 34 mm and the deformation is 2 mm, which is an amount sufficiently included in an allowable range in a normal gas pipe or the like. Thus, it can be seen that restricting the separation between the first intersection 9a and the second intersection 9b is effective in maintaining the cross-sectional shape of the PE pipe P1 before and after bending.

Although the deformation is restrained by the pressing groove portion M2 on the substantially half-circumferential portion of the PE pipe P1, as is apparent from the result shown in FIG. If it is maintained well, it can be determined that the cross-sectional shape on the outer peripheral side is also well maintained.

On the other hand, as shown in FIG. 5 (b), when the conventional pressing member 2 in which the curvature R2 of the pressing groove M2 is larger than the curvature RP of the PE pipe P1 is used, the PE pipe P1
Is easily deformed along the pressing groove portion M2, the horizontal dimension is increased by about 1 mm, and the vertical dimension is reduced by about 4 mm. The maximum flattening rate in this case is about 12 since the external dimension is 34 mm and the vertical dimension is 4 mm.
%Met.

The PE pipe P1 removed from the resin pipe bending apparatus
Although it returned and deformed with the passage of time, it became stable at an angle of about 90 degrees as originally predicted. The work time required from the heating to the removal was about 20 minutes.

(Effect) According to the resin pipe bending apparatus of the present invention, since the curvature of the cross section of the pressing groove is formed smaller than the outer peripheral curvature of the cross section of the resin pipe, the resin pipe receives a bending force. At this time, it is possible to reliably prevent the cross-sectional shape from being flattened. As described above, since the cross-sectional shape of the resin pipe is favorably maintained, a bent portion of the resin pipe which does not cause a cross-sectional defect in the resin pipe and does not increase the flow resistance of the fluid flowing therethrough is obtained. be able to.
Further, since the curvature of the cross section of the receiving groove is formed to be larger than the outer peripheral curvature of the resin tube, the resin tube does not bite into the receiving member, and when the pressing member is pulled back, the resin tube is moved by the receiving member. Separated from easily. As a result, since an external force that eliminates the bending deformation applied to the resin pipe does not act on the resin pipe, the bending of the resin pipe is accurately performed, and
It can be done efficiently.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the appearance of a resin pipe bending apparatus according to the present invention.

FIG. 2 is an explanatory view showing an outline of a receiving member.

FIG. 3 is an explanatory view showing an outline of a pressing member.

FIG. 4 is an explanatory diagram showing the relationship between the time after the bending process and the return angle.

FIG. 5 is an explanatory diagram showing a change in cross-sectional shape before and after bending.

[Explanation of symbols]

 Reference Signs List 1 receiving member 2 pressing member M1 receiving groove M2 pressing groove P resin pipe R1 curvature of cross section of receiving groove R2 curvature of cross section of pressing groove RP outer peripheral curvature of resin pipe X longitudinal direction of resin pipe

Claims (2)

[Claims] 1. A resin pipe bending apparatus for receiving two positions along a longitudinal direction of a resin tube with two receiving members, respectively, and pressing a central position of the received two positions with a pressing member. And the pressing member, a receiving groove portion and a pressing groove portion having a substantially semicircular cross-sectional shape for holding the resin tube are provided separately, and the curvature of the substantially semicircular cross-section related to the receiving groove portion, It is formed to be larger than the outer peripheral curvature of the resin tube in the cross-sectional direction, and the curvature of the substantially semicircular cross-section related to the pressing groove portion of the resin tube in a cross-sectional direction perpendicular to the longitudinal direction of the resin tube. A resin tube bending device formed smaller than the outer curvature. 2. The resin pipe bending apparatus according to claim 1, wherein the pressing groove portion is configured to be able to contact a maximum outer diameter portion of the resin pipe.