JPS6132081B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rolling tubes into smaller diameter tubes. In the method, at least one area of the outer circumference of the tube is optionally brought into contact with at least one roll rotatable about its axis, the roll and the tube being moved relative to each other, Also, the roll-to-tube contact surface, which is considered to exist between two longitudinally spaced planes, is displaced relative to the longitudinal axis of the tube.

This kind of method has been published in Dutch patent application
6504723, in which a truncated pyramid-shaped tube is formed using a truncated pyramid-shaped internal mandrel and two eccentric rolls disposed within a cylindrical starting material tube. At this time, the axis of rotation of the roll is perpendicular to the longitudinal axis of the tube. The roll surface has triangular grooves defining a square cross section. In addition to being eccentric, the two rolls have interrupted roll surfaces, so that the total length of the rolls is limited to the effective circumference of the rolls.

This always requires the use of other rolls and other mandrels for different sizes and diameters of tubes;
It has the disadvantage of requiring a large amount of labor, large investment capital for rolls and mandrels, and is economically disadvantageous.

It is an object of the present invention to overcome these disadvantages and to produce tubes of very long lengths of different materials and with different starting end diameters without the use of internal mandrels and without the need for interchange of rolls. It is an object of the present invention to provide a method and an apparatus that enable rolling.

The above purpose is such that the contact surface between the rotatable rolls and the tube to be deformed forms one or more helical regions in the case of conically rolled tubes, and in the case of cylindrically rolled tubes. This is achieved by the present invention, which is formed into one or more spiral lines.

By practicing the invention, tubes of various diameters are rolled by a limited number of rolls into tubes of varying lengths and profiles, and the surface of the tube is kept closed. , thereby providing a tube with excellent corrosion resistance. Furthermore, there are many types of tubes, such as tubes with a conical shape over their entire length, or tubes of a given continuous length with a constant cross-section, which are interconnected by short conical members. Can be rolled.

Conical tubes, such as lightweight ship masts, are generally known. For example, published Dutch patent application 6402439 describes a conically tapered metal ship mast, which is manufactured by forming a metal plate into a circular shape and folding it in the longitudinal direction of the mast. However, the molded slot profile requires sealing.

Stepped inclined lightweight masts are also known, the shaped parts of which having different diameters are each welded together by means of a reducer.

The above-mentioned conventional methods require special operations, such as welding and sealing closure operations, as explained above, and lightweight masts manufactured by these methods suffer from corrosion at the weld seams, which results in mast failure. It has the disadvantage of shortening its lifespan.

Next, the present invention will be described in more detail with reference to the accompanying drawings showing examples.

Referring to the drawing, a round cylindrical tube 1, preferably of steel, is provided as a starting material, which tube is formed into a conical tube 1 with a diameter smaller than that of the starting tube 1 in an apparatus without an internal mandrel. ’.

The tube 1 is fed through a heating device 2, which heats the tube to rolling temperature. tube 1
After leaving the heating device, it comes into contact with cylindrical disk-shaped rotary drive rolls 3, 4. The rolls 3, 4 are attached to both sides of the tube. The axis of rotation A1 of each roll makes an angle α with the longitudinal axis H1 of the tube;
In this embodiment the angle α is made smaller than 90°. The contact surfaces of the rolls 3, 4 with the outer circumferential surface of the tube 1 are preferably each on a separate helical line with a cylindrical rolled tube or in a helical region with a conical rolled tube. Each roll will therefore perform part of the total deformation. The drawing shows that the rolls are moved symmetrically to each other over a distance already from the starting diameter over a distance, so that the shoulder 5 is rolled and the shoulder 5
The figure shows a state in which a is formed. The rolls 3 and 4 each have a certain rotational speed N1 around the axis A1.
As the rolls 3, 4 move closer to the longitudinal axis H1, the tube diameter becomes progressively smaller. A set of conical support rolls 6 is arranged to support the rolled tube 1'.

FIG. 3 illustrates an embodiment of an adjustment device for the rolls 3, 4. Since the adjustment devices are arranged symmetrically, only one adjustment device is illustrated.
The rolls 3, 4 are mounted on carriers 7, 8 which are movable towards and away from the longitudinal axis H1 by displacement means (not shown). The carrier 8 is provided with a support 9, at one end of which a pivot shaft 10 is arranged. A carrier 11 of a roll drive motor 12 is pivotally mounted about the pivot shaft 10. The roll motor 12, which is driven electrically or hydraulically, for example, has a roll 4 supported by a shaft 13 at its end on the longitudinal axis H1 side. A support 14 is provided at the other end of the roll motor 12.
is provided, and a pivot shaft 15 is provided at the end of the support. A piston rod 16 of a piston cylinder unit 17 is attached to the pivot shaft 15. The piston cylinder unit is controlled by supply and discharge lines 18, 19 and valves 20, 21, and the piston rod 16 is moved telescopically. The other end of the piston-cylinder unit 17 is attached to the carrier 8 by means of pivot connections 22, 23, 24. By actuation of the piston-cylinder unit, the position of the roll 4 and thus the angle α is changed, while the displacement of the slide 8 causes the roll to be moved towards or away from the longitudinal axis H1. .

Instead of equipping the rolls 3, 4 with rotating devices, the tube 1 can be moved in rotation, with the rolls 3, 4 being free to rotate about their respective axes.
Also, in this case, a pulling force K is applied to the tube 1.

With the device according to the invention, a round tube, preferably made of steel, is rolled using a conical member into a conical or cylindrical tube, such as a light mast, for example;
It is clear that other metals and/or other materials such as synthetic materials can also be processed.

It should be understood that the invention is not limited to the embodiments described above.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of an apparatus for carrying out the method according to the invention. 2 is a plan view of the apparatus of FIG. 1; FIG. FIG. 3 is a schematic side view showing a modification of the device of FIG. 1, in particular a roll adjustment device. 1... Circular tube, 1'... Conical tube, 2... Heating device, 3, 4... Roll, 6... Conical support roll,
12... Drive motor, 17... Piston cylinder unit.

Claims (1)

[Claims] 1. A method for rolling an elongated circular tube into a conical shape without using an internal mandrel, in which a portion of the tube is heated with a heater 2 in a first position, and the heated portion of the tube is heated in a second position. The peripheral edge forming surfaces of a pair of rolls 3, 4 are brought into contact with the outer surface of the tube at circumferentially spaced points around the tube, and said rolls 3, 4 are placed in a common plane containing the axis of the tube. rotation about an axis AL which expands toward said first position, whereby contact between the tube and the rolls causes a rotational movement of the tube relative to the rolls to roll the tube to a small diameter; is advanced from the heater 2 through the rolls 3, 4 by means separate from the rolls, and by moving the rolls inwardly in a direction perpendicular to the axis of the tube while the tube is being advanced through the rolls. A method of rolling tubes. 2. The rolling method according to item 1 above, wherein the angle α of the axis AL of the pair of rolls is variable. 3. The rolling method according to item 1 or 2 above, wherein the pipe is a steel pipe. 4 In an apparatus for rolling an elongated circular tube into a conical shape without using an internal mandrel, a heater 2 provided at a first position and a second
a pair of rolls having a pair of forming surfaces that contact the outer surface of the heated portion of the tube at points spaced apart in the circumferential direction of the tube, the axis AL of which is in a plane containing the axis of the tube; The rolls 3 and 4 are expanded and expanded toward the first position, and the rolls 3 and 4 are driven around their respective axes to cause the pipe to rotate in the circumferential direction relative to the rolls due to contact between the rolls and the outer surface of the tube. drive means 12 for imparting motion to reduce the diameter of the tube by said forming surface; means for advancing the tube through the heater 2 and the rolls 3, 4 independently of the rotation of said rolls; device for forming tubes, comprising means 7, 8 for inward movement in a direction perpendicular to the axis of the tube. 5. The molding apparatus according to item 4 above, wherein the tube is supported by support means 6.