Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
  • B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
  • B21C37/08—Making tubes with welded or soldered seams
  • B21C37/0815—Making tubes with welded or soldered seams without continuous longitudinal movement of the sheet during the bending operation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
  • B21D5/14—Bending sheet metal along straight lines, e.g. to form simple curves by passing between rollers
  • B21D5/143—Bending sheet metal along straight lines, e.g. to form simple curves by passing between rollers making use of a mandrel

Definitions

• the present invention relates to mandrel type pipe forming machines as described in my US patent No. 3879994 and WO90/10510 hereby incorporated herein by a cross reference.
• a process for forming a pipe from flat steel plate having a relatively high length to width ratio including the steps of engaging flat plate with a gripper rib mounted on a rotatable mandrel with the edge of the plate in the gripper rib, curving the plate around the mandrel as the mandrel is rotated, applying laterally moveable pressure roll means beneath the mandrel to apply a squeezing force to the plate and mandrel as the mandrel is rotated, the improvement including the step of applying abutment means against at least one side of the mandrel during at least partial formation of each half of the plate.
• the opposing edge of the half curved plate is engaged with the gripper rib and is curved around the mandrel as the mandrel is rotated to complete the curvature of the plate to form a substantially cylindrical section, wherein an abutment means is applied against the mandrel and plate during said curving step, and said pressure roll means is laterally and vertically offset relative to the mandrel so that a horizontal component of force is applied which is opposed by said abutment means to stabilize the mandrel at least during the final stages of said curving operation.
• the pressure roll means is laterally offset during forming of the first half and second half of the plate during which said abutment means is applied to both sides of the mandrel.
• the pressure roll means is a single roll applied to the top and bottom of the mandrel.
• a particular feature of the present invention is the positioning of the pressure roll means relative to the mandrel during the final stages of the forming operation to provide a horizontal force component which is opposed by the abutment means applying a lateral force to the mandrel.
• Figure 1 and Figure 1 a represents step 1 of the plate forming process and the associated force diagram
• Figure 2 and Figure 2a represents step 2 of the plate forming process and the associated force diagram
• Figure 3 and Figure 3a represents step 3 of the plate forming process and the associated force diagram
• Figure 4 and Figure 4a represents step 4 of the plate forming process and the associated force diagram
• Figure 5 and Figure 5a represents step 5 of the plate forming process on the second part of the plate and the associated force diagram
• Figure 6 and Figure 6a represents step 6 of the pipe forming process and the associated force diagram
• Figure 7 and Figure 7a represents step 6A of the pipe forming process and the associated force diagram
• Figure 8 and Figure 8a represents step 6B of the pipe forming process and the associated force diagram
• Figure 9 and Figure 9a represents step 7 of the pipe forming process
• Figure 10 represents the formation of the finished pipe released from the gripper rib.
• this shows step 1 of the process in which the edge of the plate is engaged with the gripper rib 3 on the mandrel.
• the plate is supported on a bed 9 and is pushed toward the gripper rib 3 by a pusher mechanism 10 schematically shown.
• Side bolster members 5 and 6 are extended downwardly to make contact with each side of the mandrel to stabilize the mandrel whilst engagement of the gripper rib with the plate is taking place.
• Figure 1a represents a schematic force diagram with F2 representing an upward force applied by the lower roller 2
• the mandrel 1 is rotatably mounted on a machine (now shown) having overhead structures supporting an overhead roll 4 and side bolster abutments 5 and 6. Additional movable stays 7 and 8 are provided for use as necessary to provide lateral support for the top roller 4 especially when the gripper is passing beneath the roller 4 and acting to force the roller 4 upwards.
• the abutments 5 and 6 are retained in position as shown in Figures 1 and 2 to maintain the mandrel straight and stabilized during the first half of the formation of the plate.
• the position of bolster abutment 6 is such that the mandrel can deflect slightly to the right by approximately 2 times the plate thickness (2 t ) so that the gripper is allowed to pass between the mandrel and the abutment 5.
• Roller 4 is engaged by the gripper in the 12 o'clock position and forced upwards at which time the abutment 5 provides a reaction force and stabilizes the mandrel until the formation of the first half of the plate as shown in Figure 3 at step 3.
• the top roll 4 and the mandrel 1 are raised together with a slightly anti-clockwise rotation of the mandrel to allow release of the plate from the gripper as shown.
• the other edge of the plate is fitted to the gripper rib 4 with a lower pressure roll 2 positioned off centre a distance e1 as shown Figure 5.
• the curved part of the plate is contacted by an abutment member 11 to force the edge of the plate into engagement with the gripper.
• Simultaneously bolster members 5 and 6 are located against the mandrel to stabilize its position resulting in a force diagram as shown in Figure 5a with vertical forces F4, F2 and horizontal force components F11H, F6 and F5.
• the side abutment member 5 is positioned in a similar manner to side abutment 6 was positioned in step 2 as shown in Figure 2 previously described to allow passage of the gripper at the 3 o'clock position past the abutment 6. Therefore the mandrel is able to deflect to the left by a distance of twice the plate thickness (2 t ) whilst the gripper is at the 3 o'clock position.
• abutment 6 provides the opposite reaction force as that provided by abutment 5 in step 2 described above to allow the roller 4 to be forced upwardly by the passage of the gripper at the 12 o'clock position at this point as shown in Figure 7 abutment 5 must be retracted to allow clearance for the previously formed plate edge as the final half of the plate is formed.
• Figure 9 representing step 7 shows the completed pass with the lower roller 2 being again moved into alignment or almost into alignment with the centre line of the mandrel so that the lower roller 2 can adequately match the high forces required in the final stages of rolling of the plate. That is distance e3 is almost 0 depending on the D/ t ratio, the yield strength of the steel plate and other factors affecting the spring back of the steel.
• Figure 11 shows step 8 of the process which illustrates the release of the curved plate from the gripper rib and the completion of the curving operation of the plate ready for welding of the joint in the cylindrical section to form a finished pipe.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Bending Of Plates, Rods, And Pipes (AREA)

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Publications (1)

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ID=3776825

Family Applications (1)

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Cited By (1)

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Citations (7)

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• 1994
  • 1994-03-31 GB GB9520204A patent/GB2291609B/en not_active Expired - Fee Related
  • 1994-03-31 WO PCT/AU1994/000161 patent/WO1994022608A1/en active Application Filing
  • 1994-03-31 SG SG1996003266A patent/SG54178A1/en unknown
  • 1994-03-31 CN CN94191686A patent/CN1053404C/zh not_active Expired - Fee Related
  • 1994-07-18 TW TW83106558A patent/TW265284B/zh active

Patent Citations (7)

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