JP3632159B2 - Tube expansion device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe expansion device used for expanding an end of a pipe when connecting the pipe and the joint or the pipe and the pipe in piping work of a gas pipe or a water pipe, for example.
[0002]
[Prior art]
The present applicant has proposed the one shown in FIG. 5 in Japanese Patent Application No. 8-45435 as a tube expansion device for expanding the ends of steel tubes, lead tubes, copper tubes, polyethylene tubes and the like.
[0003]
This conventional pipe expanding apparatus has a rod 50 having an extended head 53 provided with a truncated cone part 52a, 52b having an inclined surface extending in the distal direction in a stepwise manner, and a plurality of inclined surfaces 54 provided on the inner side. The pipe 55 is disposed around the rod 50 and is formed by a tube expansion member 51 formed by focusing with elastic rings 56a and 56b. By pulling the rod 50 with a hydraulic ram 57 in the proximal direction, The base end face 51a of the pipe expanding member 51 is brought into pressure contact with the distal end face 57a of the ram 57, and the pipe expanding member 51 is expanded by the expansion head 53 of the rod 50, thereby expanding the end portion of the pipe 58 set on the outer peripheral surface of the pipe expanding member 51. It is a diameter.
[0004]
In this conventional tube expanding device, the tube expanding member 51 is made long, and the pressure contact portion between the expansion head 53 and the tube expanding member 51 during operation is divided into two front and rear portions, and the tube expanding portion 58a of the tube 58 is expanded to a length. At the same time, by setting the inclination angle of the first truncated cone portion 52a of the expansion head 53 and the inclination angle of the inclined surface 54 inside the piece 55 that is in pressure contact during operation to be different from each other, the pressure contact point is brought into line contact and slides. The frictional resistance at the time is reduced and the movement of the device is lightened.
[0005]
[Problems to be solved by the invention]
The above-described conventional tube expansion device can be formed with a light and easy expansion of the end portion of the tube 58, but by opening the rod 50, the tube 58 is opened from the proximal end side of the tube expansion portion 58a, that is, from the back of the tube 58. Since the expansion head 53 moves toward the end so that the expansion member 51 is expanded and expanded, it is difficult to apply expansion pressure to the proximal end side and the open end side of the expanded portion 58a in a balanced manner. Depending on the material and thickness of the tube, the expansion of the expanded portion 58a on the opening end side may be insufficient compared to the proximal end side, and when the pulling force of the rod 50 is increased, the focusing force balance of the elastic rings 56a and 56b is balanced. The device was troublesome to adjust, such as collapsed and unevenly expanded.
[0006]
In addition, those that are plastically deformed and expanded in diameter, such as lead pipes and copper pipes, maintain the expanded state, so if the expanded portion 58a is expanded uniformly in parallel, there is no problem in the connection work of the tube, In the case of a polyethylene tube that is elastically deformed and expanded, the expanded portion is elastically restored, so that contraction starts immediately after the diameter expansion, and the tube connection work time is shortened. Accordingly, it is necessary to secure the expanded state for as long as possible to facilitate the connection work, and it is possible to expand the tube in a truncated cone shape by making the opening end side of the expanded portion 58a larger than the proximal end side. preferable. However, the above-described conventional tube expansion device cannot form such a tube expansion.
[0007]
The present invention has been made in view of the above problems, and is suitable for a polyethylene pipe in which the end of the pipe can be expanded in a uniform and parallel manner by applying expansion pressure in a balanced manner to the expanded section, and the expanded section is elastically contracted. It is an object to improve so that the diameter can be expanded to a truncated cone shape.
[0008]
[Means for Solving the Problems]
In the present invention, a rod provided with a truncated cone projecting on a piston operated by a ram and extending in the distal direction, and a plurality of pieces arranged surrounding the peripheral surface of the rod are extendable in the radial direction. And a tapered bush provided with a conical cylinder portion which is penetrated by the rod and is attached to the back of the expanded member and is constricted in the distal direction. The tapered bush is connected to the ram. The tube portion can be expanded in a well-balanced manner by abutting the distal end surface, operating the piston to retract the rod, and expanding the tube expansion member from the front and the back with the truncated cone portion and the cone tube portion. .
[0009]
Further, by setting the axial dimension of the conical cylinder part to be longer than the axial dimension of the frustoconical part, the expanded tube portion can be expanded into a truncated cone shape.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
[0011]
1 to 4 show one of the preferred embodiments of the tube expansion device of the present invention. As shown in FIGS. 1 and 2, the tube 2 is attached to a piston 2 operated by a ram 1 and spreads in the distal direction. A rod 3 having a truncated cone part 4 at its tip, and six pieces 11 disposed around the peripheral surface of the rod 3 are converged by elastic rings 12a and 12b so as to be elastic in the radial direction. It comprises a member 10 and a tapered bush 20 having a conical tube portion 21 that is inserted through the rod 3 and is inserted into the tube expansion member 10 from the rear side and constricted in the distal direction.
[0012]
The ram 1 is a hydraulic type that operates a rod 3 attached to a piston 2 in a cylinder 1a. The mechanism for operating the rod 3 is not limited to a hydraulic ram, and may be a screw or a spring.
[0013]
The rod 3 is a bolt-shaped steel rod that penetrates through the center of the piston 2 and is attached to the base end portion with a nut 5, and the distal end portion thereof is connected to the truncated cone portion 4 via a short parallel portion 6. The bolt head 7 has a diameter larger than that of the parallel portion 6, and the bolt head 7 is provided with a driver insertion groove 8.
[0014]
The pipe expansion member 10 has a piece 11 (see FIG. 2) disposed on the periphery of the rod 3 so as to be split in a split shape around the rod 3 (FIG. 2). And an elastic ring 12 that can be stretched and contracted freely.
[0015]
The piece 11 has an L-shaped cross section and constitutes a parallel tubular portion 10a and a flange portion 10b of the tube expansion member 10, and is provided at two locations on the front outer peripheral surface of the tubular portion 10a and the outer peripheral surface of the flange portion 10b. Are provided with recessed grooves 13a and 13b into which the elastic rings 12a and 12b are fitted.
[0016]
In addition, inclined holes 14 and 15 through which the truncated cone part 4 and the conical cylinder part 21 are viewed from the front and rear direction are formed at the front and rear ends of the shaft hole 10 d of the pipe expanding member 10. The inclination angles of the inclined surfaces of the two inclined holes 14 and 15 and the truncated cone part 4 and the conical cylinder part 21 are set to the same angle. When the device is operated, that is, when the rod 3 is drawn into the ram 1, the inclined holes 14 and 15 at the two front and rear ends of the pipe expanding member 10 are respectively formed at the two front and rear conical portions 4 and 21, respectively. It comes into contact and slides.
[0017]
The inclination angle of the inclined hole 14 at the rear end of the pipe expanding member 10 that is in pressure contact with the conical cylinder portion 21 is set to be wider than the inclination angle of the conical cylinder portion 21, and the frictional resistance is set by making the rear sliding contact point a line contact. Needless to say, it is also possible to make the value smaller (not shown).
[0018]
The elastic rings 12a and 12b are formed of an elastic material such as a coil spring, a metal spring, or rubber, and are provided so as to be freely removed from the recessed grooves 13a and 13b of the tube expansion member 10.
[0019]
The taper bush 20 is an integrated body composed of a flange portion 22 and a conical cylinder portion 21 projecting from the center thereof. The rod 3 penetrates the shaft hole 10d and is coaxial with the tube expansion member 10 behind the tube expansion member 10. It is installed. The axial dimension M1 of the conical cylinder part 21 is set longer than the axial dimension M2 of the truncated cone part 4 of the rod 3. Moreover, the front end surface 21a of the conical cylinder part 21 has a diameter that looks into the inclined hole 14 at the rear end of the pipe expanding member 10.
[0020]
When tube expansion work is performed using the tube expansion device of the present embodiment configured as described above, as shown in FIG. 3, the tubular portion 10a of the tube expansion member 10 is attached to the end portion of the tube 25 to be expanded. The piston 2 is operated by the ram 1 to pull the rod 3, and the taper bush 20, which is linked coaxially with the tube expansion member 10, is attracted to the ram 1 side. Press contact with 1b.
[0021]
When the rod 3 is further retracted, the conical cylinder portion 21 of the tapered bush 20 is press-fitted into the inclined hole 14 at the rear end of the tube expansion member 10, and the tube expansion member 10 is pushed open from the rear against the focusing force of the rear elastic ring 12 a. At the same time, the truncated cone part 4 of the rod 3 is also press-fitted into the inclined hole 15 at the tip of the tube expansion member 10 to push open the tube expansion member 10 from the front against the focusing force of the front elastic ring 12b.
[0022]
Accordingly, the pipe expansion member 10 is expanded from the front and rear sides to the inside by the two inclined holes 14 and 15 at the front and rear ends and the two front and rear conical parts 4 and 21, and the pipe expansion portion 25a of the pipe 25 is at an expansion pressure balanced in the front and rear direction. Tube expansion is formed.
[0023]
Further, since the inclined angles of the inclined surfaces of the truncated cone part 4 and the conical cylinder part 21 are set to the same angle, the piece 11 moves in the radial direction while being in a parallel state, and the inclined hole 14 at the tip 10c of the pipe expanding member 10 is used. Until it reaches the parallel portion 6 which is the maximum diameter portion of the truncated cone portion 4, it can be expanded uniformly in parallel in proportion to the pull-in amount of the rod (FIG. 3).
[0024]
Therefore, when the pipe 25 that is plastically deformed like a metal pipe is expanded uniformly in parallel, the diameter expansion dimension of the pipe expansion portion 25a may be adjusted to a desired size by the amount of the rod 3 drawn.
[0025]
Further, in the present embodiment, the axial dimension M1 of the conical cylinder part 21 is formed longer than the axial dimension M2 of the truncated cone part 4, and the parallel tube expansion state shown in FIG. When the rod 3 is further pulled in, as shown in FIG. 4, the tip 10c of the tube expansion member 20 comes into contact with the bolt head 7, and only the flange portion 22 side of the tube expansion member 20 is further expanded by the conical cylinder portion 21, thereby expanding the tube. The portion 25a can be expanded into a truncated cone shape having a wide opening.
[0026]
Therefore, it is a suitable tube expansion method for the tube expansion portion 25a, such as a polyethylene tube, that is elastically restored and starts contracting immediately after the diameter expansion and the tube connection work time is shortened. The diameter can be greatly expanded to ensure the time for connection work.
[0027]
When the tube expansion process is finished, the rod 3 is protruded to cancel the expansion force of the tube expansion member 10. Then, the tube expansion member 10 contracts the inclined surfaces of the two conical portions 4 and 21 to the original shape by the focusing force of the elastic rings 12a and 12b. Therefore, the pipe 25 is simply pulled out from the pipe expanding device to complete the pipe expanding operation.
[0028]
【The invention's effect】
The present invention is implemented in the form as described above, and has the following effects.
[0029]
According to the tube expansion device of the first aspect, a plurality of pieces are arranged surrounding the circumferential surface of the rod having a truncated cone portion extending in the distal end direction at the distal end portion, and this can be expanded and contracted in the radial direction by the elastic ring. The tube expansion member is formed by concentrating the tube expansion member, and a tapered bush having a conical cylinder portion is provided coaxially with the tube expansion member, and by pulling the rod, the tube expansion member is wedged from the front and rear by the truncated cone portion and the conical cylinder portion. Since expansion is performed so as to drive, the expansion pressure is simultaneously applied in a balanced manner to the proximal end side and the open end side of the expanded tube portion, and the expanded tube portion is expanded in size and without distortion without complicated adjustment of the device. can do.
[0030]
In addition, in the tube expansion device according to claim 2, in addition to the above effect, the axial dimension of the conical cylinder part is longer than the axial dimension of the truncated cone part. By pulling in the rod, the flange side of the tube expansion member can be further expanded, and the tube expansion portion can be expanded into a truncated cone shape having a wide opening. Therefore, the contraction of the expanded portion of the elastically recoverable tube such as a polyethylene tube can be delayed, and the connection work is facilitated. Moreover, since the expanded portion can be expanded to a parallel shape or a truncated cone shape with a single device, it is possible to deal with tubes of various materials and is economical.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a tube expansion device of the present invention.
FIG. 2 is a rear view of a tube expansion member used in the tube expansion device of FIG.
FIG. 3 is a cross-sectional view showing an operating state in which a tube expansion portion is expanded in parallel by the tube expansion device of FIG. 1;
4 is a cross-sectional view showing an operating state in which a tube expansion portion is expanded into a truncated cone shape by the tube expansion device of FIG. 1. FIG.
FIG. 5 is a cross-sectional view showing a conventional tube expansion device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ram, 1b Tip surface, 2 Piston, 3 Rod, 4 Frustum part, 10 Expanding member, 11 pieces, 12a, 12b Elastic ring, 20 Taper bush, 21 Conical cylinder part

Claims (2)

A rod provided with a truncated cone portion projecting from a piston operated by a ram and extending in the tip direction, and a plurality of pieces arranged around the periphery of the rod are elastic rings that can expand and contract in the radial direction. And a tapered bushing having a conical tube portion that penetrates the rod and is mounted behind the expanding member and is constricted in the distal direction. The tapered bushing abuts the distal end surface of the ram. A tube expansion device that expands the tube by bringing the tube into contact with each other, operating the piston to retract the rod, and expanding the tube expansion member from the front and the back with the truncated cone portion and the cone tube portion. 2. The tube expansion device according to claim 1, wherein the axial dimension of the conical cylinder part is longer than the axial dimension of the truncated cone part.

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