(19)
(11) EP 0 799 659 A2

(12) EUROPEAN PATENT APPLICATION

(43) Date of publication:
08.10.1997 Bulletin 1997/41

(21) Application number: 97200891.6

(22) Date of filing: 24.03.1997
(51) International Patent Classification (IPC)6B21D 51/20
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 05.04.1996 NL 1002805
27.09.1996 NL 1004126

(71) Applicant: Hoogovens Staal B.V.
NL-1970 CA IJmuiden (NL)

(72) Inventors:
  • Thoolen, Friedrich Wilhelmus
    1943 GR Beverwijk (NL)
  • Vermeij, Johannes
    1852 CP Heiloo (NL)
  • de Lange, Johannes
    1966 PA Heemskerk (NL)

(74) Representative: Wentzel, Hendrik Cornelis et al
Hoogovens Corporate Services BV, Industrial Property Department, P.O. Box 10000
1970 CA IJmuiden
1970 CA IJmuiden (NL)

   


(54) Method and apparatus for manufacturing steel drums


(57) Method for manufacturing steel drums comprising the stages:

(1) uncoiling a steel strip from a coil

(2) manufacturing from the strip in a continuous process a spirally welded tube with a diameter mainly equal to the diameter of the drum to be manufactured, whereby the pitch angle is set in dependency of the width of the steel strip

(3) cutting off from the spirally welded tube pieces with a length mainly equal to the body length of the drum to be manufactured

(4) providing the drum body with lids on both of its ends.






Description


[0001] The invention relates to a method and apparatus for manufacturing steel drums.

[0002] In accordance with the state of the art steel drums are manufactured from steel plate which is welded by seam-welding after being bent into a body.

[0003] The problem with this is the high costs connected with this non continuous production technique and the associated quality problems such as start and end of the weld, at the ends of the body.

[0004] The object of the invention is to provide a method and apparatus allowing drum bodies to be produced in a continuous process.

[0005] In accordance with the invention this is achieved by a method for manufacturing steel drums comprising the stages:

(1) uncoiling a steel strip from a coil

(2) manufacturing from the strip in a continuous process a spirally welded tube with a diameter essentially equal to the diameter of the drum to be manufactured, whereby the pitch angle is set in dependency of the width of the steep strip

(3) cutting off from the spirally welded tube pieces with a length essentially equal to the body length of the drum to be manufactured

(4) providing the drum body with lids on both of its ends.



[0006] In a special embodiment of the method the subsequent coils have a varying width and the coils are processed without slitting by setting the pitch in dependency of each new width.

[0007] The invention is also embodied in an apparatus for manufacturing steel drums comprising:
  • means for uncoiling a steel strip from a coil
  • means for conveying the steel strip from the coil to means for bending the steel strip
  • means for bending in a spiral fashion the steel strip into a tube shaped spiral comprising means for setting the pitch angle
  • means for welding the spiralled tube
  • means for cutting off from the spiralled tube bodies for the steel drums
  • means for providing the drum body with lids on both of its ends.
Preferably the means for setting the pitch angle comprise a turnable.

[0008] The advantages of this are:
  • the steel is less expensive by the coil than by the plate
  • less material handling of the coils is required than with the plates of the state of the art
  • with the invention variable material widths can be used allowing an inexpensive second choice material to be used; slitting is no longer required
  • there is no material loss
  • the continuous welding process can be better controlled and produces a more consistent quality than with the state of the art at the start and end of the weld
  • the bodies are exactly cylindrical
  • the spirally formed weld seam makes the drum stronger and stiffer.


[0009] The invention will now be illustrated by reference to the drawing.

[0010] The only drawing shows an apparatus in accordance with the invention.

[0011] Steel strip (1) is uncoiled for example on an uncoiling reel (not shown) from a coil (not shown). The steel strip (1) is conveyed to means for bending the steel strip and there bent in spiral fashion into a tube shaped spiral (6) having a pitch angle.

[0012] These means consist of for example the adjustable bending roll (2) and inner bending roll (3) together with driven bending rolls (4) and (5). The steel strip is fed under tension and at such a pitch angle that the strip edges abut seamlessly. The pitch angle at which the steel strip arrives on the bending roll is critical and determines whether the steel strip runs off or butts. This is adjusted with the turntable (9).

[0013] Then the tube shaped spiral (6) is welded with a welding unit (not drawn) at (7) into a spirally welded tube. A high frequency welding module is excellent to use for continuously welding the spirally welded tube. The spirally welded tube is conveyed by the conveyor (10).

[0014] Pieces (8) with a length such as needed for the drum body are cut off from the spirally welded tube for example with a shear blade rotationally, axially and radially driven at (11), (12) and (13). Finally, after some intermediate processes such as applying stiffening ribs and preparing the drum body ends, this drum body is provided with lids at both ends.

[0015] A particular advantage of the invention is that compared to the state of the art minimum material handling is required and the production line is very short.


Claims

1. Method for manufacturing steel drums comprising the stages:

(1) uncoiling a steel strip from a coil

(2) manufacturing from the strip in a continuous process a spirally welded tube with a diameter mainly equal to the diameter of the drum to be manufactured, whereby the pitch angle is set in dependency of the width of the steel strip

(3) cutting off from the spirally welded tube pieces with a length mainly equal to the body length of the drum to be manufactured

(4) providing the drum body with lids on both of its ends.


 
2. Method in accordance with claim 1 whereby subsequent coils have a varying width and whereby the coils are processed without slitting by setting the pitch angle in dependency of each new width.
 
3. Apparatus for manufacturing steel drums comprising:

- means for uncoiling a steel strip from a coil

- means for conveying the steel strip from the coil to means for bending the steel strip

- means for bending in a spiral fashion the steel strip into a tube shaped spiral comprising means for setting the pitch angle

- means for welding the spiralled tube

- means for cutting off from the spiralled tube bodies for the steel drums

- means for providing the drum body with lids on both of its ends.


 
4. Apparatus in accordance with claim 3 whereby the means for setting the pitch angle comprise a turnable (9).
 




Drawing