US 3905536 A
An apparatus for use in the production of spiral-welded tubes or pipes, which comprises a triple roller bending system of a forming body including an outer guide roller device and an inner guide roller device. A first row of rollers is at least individually supported on a beam hydraulically adjustable in a substantially vertical direction on hydraulic cylinders. The adjustment of the displacement stroke of each of the cylinders is effected in such manner that a triple roller bending system is set in accordance with a previously determined relationship between oil pressure and displacement stroke.
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Description (OCR text may contain errors)
United States Patent 1 Claussen [4 1 Sept. 16, 1975 .4] APPARATUS FOR USE IN THE PRODUCTION OF SPIRAL-WELDED TUBES OR PIPES  Inventor:
 Assignee: Berliner Maschinenbau-AG vormals L. Schwartzkopff, Berlin, Germany Mar. 9, 1973 Lorenz Claussen, Berlin, Germany  Filed:
21 Appl. No.1 339,868
 Foreign Application Priority Data Mar. 13, 1972 Germany "2212744  US. Cl. 228/17; 228/5; 228/9; 219/62; 72/170 [51 Int. Cl... B23k 37/04; B2lC 37/06; 1321c 37/08  Field of Search....; 228/5, 15, 1 7, 8, 9; 29/4773; 2l9/62; 72/l70  References Cited UNITED STATES PATENTS 1,659,754 2/1928 Thorsky 219/62X 3,093,103 6/1963 Berkeley. 228/17 X 3,146,331 8/1964 Schubert..... 228/17 X 3,208,138 9/1965 Eckhardt 29/4773 Primary ExaminerFrancis S. Husar Assistant Examiner-Gus T. Hampilos Attorney, Agent, or Firm-Ernest G. Montague; Karl F. Ross; Herbert Dubno [5 7 ABSTRACT An apparatus for use in the production of spiralwelded tubes or pipes, which comprises a triple roller bending system of a forming body including an outer guide roller device and an inner guide roller device. A first row of rollers is at least individually supported on a beam hydraulically adjustable in a substantially vertical direction on hydraulic cylinders. The adjustment of the displacement stroke of each of the cylinders is efiected in such manner that a triple roller bending system is set in accordance with a previously determined relationship between oil pressure and displacement stroke.
1 Claim, 2 Drawing Figures APPARATUS FOR USE IN THE PRODUCTION OF SPIRAL-WELDED TUBES OR PIPES.
The present invention concerns apparatus for use in the production of helically welded tubes in which the displacement or stroke of the bending tool can be manually or automatically adjusted in operation so that even with very different properties of material, various.
tubes (pipes) can be produced without strain or tension or with a desired amount of tension. I
Forming tools for the production ofspiral-welded tubes having an outer and ,inner guide are already known and comprise a triple roller bending system and guide rollers which are arranged either in the form of an outer cage or inner star. Forming bodiesare already known in which the triple roller bending system is adjusted in dependence upon the contact pressure, measured by means of pressure boxes between shaped (deformed) sheet metal and guide rollers behind the triple roller bending system so that the said contact pressure and, consequently, the amount of springing up of the pipes is as low as possible. The disadvantage of this arrangement is that thepressure measurementas a value indicator of the displacement of the triple roller bending system is too inaccurate and, in addition, depending on the position of the pressure. measuring boxes, forrex ample on the welding gap control of the machine, can be influenced so that t he measuredpressureis nota measure of the contact ratios of the deformed sheetmetal to the guide rollers. Corresponding adjustment .of the triple roller bending system would lead to incorrect results. i
The present invention however, relatesto a forming body, the triple roller bending system of which is constroke control are effected in the triple roller bending,
The essential difference between conventional arrangements and that of the present application is there-v fore that in the first case of the contact pressure sul: jected to many secondary influences is usedbehind the triple pressurebend ing system, and in the second casev according to the present invention, a-theoretically and- /or experimentally predeterminedstroke is.used in the triple rollerbending systemas astandard value forthe correct positioning of the bending system,
The arrangement of the present invention comprises a triple roller bending system, thefront andmiddle.
bending beam' of which comprising roller supports which are preferably hydraulically adjusted, either over is adjusted, dependantly on the property of the material, corresponding to a stroke dependance readily and correctly ascertainable experimentally for each type of steel, for producing tubes without tension. If, for example, the strength of the material rises, then the bending moment rises and therewith the action of force from the band on the hydraulic pressure cylinder of the arrangement of the present invention. At the same time the pressure in the closed stroke-connolled system also ing amount.
rises without anyinitially change in the-positioning of the stroke;
The adjustment of the triple roller bending system is not effected in the conventional manner, i.e., purely pressure-dependantly, since the maintenance of a certain pressure on the bending roller and, consequently, also a certain bending moment, still fail to guarantee a uniform springing up amount e.g. almost zero, or makes possible the maintenance of anydesired spring- Aswell known, the band material for shaping the tube is plastically bent-over and when the strain or flow limit of the material is reached during the plastic bending-over, the necessary bending moment no longer rises or-only rises so slightly thatthis change in the bending moment can no longer be measured. reliably in a pipeforming machine. Y
The amount of springing-up (or in) of a pipe is determined, exactly as in the bending over of the band material so that the bending over diameter necessary for the springing up measurement zero or for any other desired springing up measurement is maintained. The latter bending over-diameter depends, however, on the fluctuations of theithickness of the material, which are relatively slight, and on the fluctuations in the strength of jointly or each roller separately in a vertical or inclined direction. This adjustment is effected preferably with stroke-contrblled hydraulic cylinders. .The stroke of the hydraulic pistons is not controlledrin the already known manner 'so that contact pressure indicator used as a value indicator, is reduced as much as possible behind the triple roller 'bending'system, butin accordance with the present invention, in such manner that the bending the material, which are relatively large and which is measured by theforce on the rollers of the bending system just as the fluctuations in the thickness of the mate rial are measured. With variations. in this force, the bending system musttherefore be adjusted and it must be again pointed out that. the force does not change with such an adjustment.
In accordance with the present invention, the-triple roller bending system is therefore positioned either by vertical or slightly inclined adjustment 0f the front bending beam alone or with an oppositely directed movement of the middle bending beam together so that a' change of stroke eorresponds to the rise in pressure in the closed strokecontrolled system with the increase in the strength of the material, said change of stroke being obtained experimentally and/or theoretically for each material quality so that pipes without tension are produced or pipes with a desired amount of springing up or tension are produced. Accordingly, the same applies to positioning in a reduction of the material strength. The preferred hydraulic adjustment of the bending beam or beams of the individual roller cylinder or cylinders can be effected manually or automatically by corresponding positions of the control valves. For example, a'stroke scale found for each quality of steel can be arranged around the pressure gauge said scale associating the correct position with each change of pressure.
The invention will be described further, by way of example, with reference to the accompanying drawing in whichi. v
FIG. 1 is a schematic cross-section through a forming arrangemermand FIG. 2 is aperspectiveview of a particular embodivThe present invention utilizes a three roller bending system'which is generallyformed of a series of rollers, namely: a first row, a-second upper row and a third row which are arranged to form desired bending of a band of pipe material.
t A guide cage is formed by rows of rollers 4 which rows are adjusted initially for a desired diameter of finished pipe and preferably remain unchanged in operation.
Similarly, a row of rollers 3 associated with the triple roller bending system is adjusted for the desired finished pipe diameter and preferably remain unchanged in operation. 1
In contrast to this, row of rollers 2 is adjustable in operation so that they bend incoming band 5 to a diameter which is less than the desired finished diameter. In the embodiment shown, the adjustment of the roller 1 is effected by a hydraulic cylinder 7 which is secured to the machine frame 6 and has a piston rod 8 which carries the roller 1. Each of the rollers is therefore guided and positioned by a cylinder. However, in an alternative arrangement (not shown), all the rollers of the first row may be carried by a common beam and this beam. can be hydraulically or mechanically adjusted. I
In the embodiment shown, the adjustment indication for the position of the row 1 is effected by a bar 9 which actuates the feeler 10 of a hydraulic copy feeler ll (e.g.- a valve of a serv'omechanismsee page 407 of Servomechanism Practice, McGraw-Hill, 1960). The copy feeler 11 is mechanically connected to the piston rod 8 by a rod. If, for example, the bar 9 is raised, the feeler 10 is pressed in and permits the flow of oil to raise thepiston and, consequently the roller 1. Since the entire copy feeler also rises with the roller 1, the raising of the roller 1 is concluded when the feeler l0 resumes the previous position relative to the bar 9, that is, when the roller 1 has directly copied the adjustment of the bar'9.-
It must beemphasised that an electro-hydraulic or electro-mechanical or other adjustment may also be provided, instead of the described direct hydraulic copying.
The fluctuation in the strength of the material and/or the fluctuations in the thickness of the incoming band 5 determine the forces on the rollers 1,2 and 3. This force is read from the pressure gauge 13 and corresponding pressure gauges may be also provided for the row 2.
For a specific pipe and quality of material reference to the pressure gauge 13 gives an indication of the strength of the material. The correct bending-over diameter associated with the material or the positioning of the rows of rollers 2 and/or 1 is obtained experimentally and/or theoretically and can be given manually or by an automatic indication, for example, by a cam disc acting on the bar 9 or a corresponding member for row 2, which in turn adjusts the rollers 2 and/or 1 accordingly.
After leaving the triple roller bending system that is upon leaving the row of the rollers 3, the tube expands to the (greater)finished diameter or until it comes into contact with the rollers 4. It is always possible to obtain and indicate the bending-over diameter so that the expanded diameter (in which therefore no uncompensated inner strains remain in the pipe wall) is equal to the desired finished-pipe diameter. In this case, the springing-up measurement is zero. In practice it may be preferable to leave a small amount of pressure ori the rollers 4 to guide the pipe and in order to maintain the finished pipe diameter more simply and accurately. This pressure on the rollers 4 is not directly measured, however, but maintained by a correspondingly corrected positioning of rows 1 and 2.
According to FIG. 1, the triple roller bending system is arranged so that the incoming band runs horizontally or substantially horizontally which results in a simpler machine construction and the bent-over on the roller 3 merges tangentially into the finished diameter. Since it is only here that the incoming band runs parallel to the already finished pipe with which it is to be welded, the welding point is just ahead or on the other side of the roller 3. This position of the welding point in the rising band is simultaneously the preferred position for protective gas tack or finished welding. The arrangement shown is therefore preferably provided for socalled tack-welding machines.
However, it' must be emphasised that the forming systern of the present invention is also suitable for sub merged arc welding. Since in such welding the welding point must lie inor near the lowest point, the triple roller bending system is turned further forwardly towards the band inlet). In this case the band must enter at an incline from above or first outwardly over the first roller that is, must be bent oppositely since in each case the sheet metal must be bent over within the triple roller bending-system to a diameter which is less than the finished diameter. I i
FIG. 2 is a part perspective view of an embodiment of the present invention and shows in detail a preferred supporting arrangement of a single roller 1 (or for a roller 2) by respective hydraulic cylinders. The same references are used in FIG. 2 as in FIG. 1 when referring to identical parts.
Furthermore the embodiment of FIG. 2 is supplemented relative to FIG. I by footplate 21 by which the unit is connected to the machine frame. Also, a track rod 22 is provided for adjusting all the rollers 1 parallel to the band inlet angle by way of the bolt 23 and the rod 8.
An important feature of FIG. 2 is that the bar 24 (which indicates or dictates the position) is not supported on the machine frame, but has asupport (not shown)--separate from the frame supporting the triple roller bending system. The advantage of this arrangement is that the elastic deformation of the machine frame originating from the very great bending forces, no longer influences the rated value indication.
Further advantages of the individual supporting arrangement of the roller include that defects in a supporting arrangement no longer have any adverse influence on the machine; and that the roller either presses continuously fully against the 'band, but is unable to bend it reliably alone or it moves into the other position whilst its load is received by the other rollers. A repair is preferably effected by exchanging a complete unit and for this purpose the band need not be removed from the machine.
Finally it is possible to operate the cylinders and preferably the upper cylinders, hydraulically 'so that they can deflect pressures toward the hydraulic system upon the exceeding of a certain pressure. In this manner the (raised) cross welding seam can pass without raising more than one roller and without overloading this or its supporting system or themachine frame.
Another embodiment of the present invention resides in that the band is arranged to run into the bending system horizontally or substantially horizontally and is bent over here to a diameter which is less than the finished diameter so that the entering band is higher than the lower point of the finished pipe.
1. In an apparatus for the production of helicalwelded pipe having guide means defining a circular path for a metal band and welding means for welding each turn as formed to previous turns of the band to form a helical seam pipe, the improvement which comprises: a
bending means forimparting a bend to a oncoming band, said bending means comprising a first roller initially encountering said band, a second roller downstream of said first roller and subsequently encountering said band and a third roller downstream of said second roller and encountering said band thereafter, said first and third rollers engaging an external surface of the band to be bent and said second roller engaging an internal surface thereof, said rollers defining a circular arc having a radius of curvature less than the radius of said pipe; pressurizable means for displacing one of said first and second rollers to adjust the curvature of the bend formed in said band, said guide means and the others of said rollers having a common frame;
a support independent of said frame for carrying said one of said rollers;
a device responsive to the position of said one of said rollers for controlling said pressurizable means; and
adjusting means including-a bar mounted on said support and between said support and said device for setting the position of said one of said rollers in accordance with characteristics of the band, said device detecting the spacing of said one of said rollers from said bar to control said pressurizable means.
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