IE46813B1

IE46813B1 - Manufacture of pipe bends with straight limbs

Info

Publication number: IE46813B1
Application number: IE859/78A
Authority: IE
Inventors: Rolf Koser; Egon Haberstock; Anton Beidenbend; Manfred Wonderschuetz
Original assignee: Moeller Sidro Fab
Priority date: 1977-04-30
Filing date: 1978-05-01
Publication date: 1983-10-05
Also published as: CH629123A5; AT360819B; FR2388612A1; ATA306678A; JPS53135873A; NL176235C; DE2719353C3; NL7804609A; IT7822850A0; IT1095342B; NL176235B; FR2388612B1; IE780859L; GB1603538A; DE2719353A1; DE2719353B2

Abstract

In the method, use is made of tube bends which are produced from a relatively narrow straight tube using a correspondingly shaped mandrel. The tangential cylindrical leg extensions are obtained by restoring the shape of the end of the tube bend by a procedure in which forming tools that act from outside on the end of the tube bend and/or mandrels, plungers or rollers to be inserted into the end of the tube bend straighten the end of the tube bend. For this purpose, a die plate (6) is clamped onto the table of an eccentric press and cooperates with a ram (7) moved up and down by the eccentric. The end (11) of the tube bend is inserted between the die plate (6) and the ram (7) and rotated. Alternatively, use can be made of an apparatus in which an end (18) of a tube bend is inserted between two die jaws (14, 15) which open and close briefly, while a mandrel provided with pressure rollers (16, 17) is introduced into the end of the tube.

Description

The present invention relates to a method and apparatus for producing a bent pipe having at least one straight end portion of circular cross-section.

In German (Fed. Rep.) Patent Specification Nos. 367,513, 583,550 and 573,890, a method of making pipe bends is described, in which a pipe bend with uniform wall thickness is produced out of a narrower straight pipe. According to this method the straight pipe is so enlarged on pushing over a mandrel that a pipe bend of round cross-section arises.

The pipe bends produced by known method are continuously curved uniformly. In the metal industry, however, pipe bends are frequently needed which have straight limbs. The limbs are produced by welding pipe stubs to the finished pipe bends. For high quality, the welded seams must be subjected to a further processing, which according to quality can be very expensive.

According to one aspect of the present invention there is provided a method of producing a bent pipe length having a diameter greater than that of the straight pipe length and comprising a bent portion and at least one adjoining straight portion of circular cross-section, the method iconprising the steps of bending the straight pipe length -5into a continuous curve and subsequently straightening at least one of the end portions of the pipe length hy reshaping tool means engaging said at least one end portion and acting thereon over a cylindrical work region.

According to another aspect of the present invention there is provided apparatus for producing a bent pipe length having a diameter greater than that of the straight pipe length and comprising a bent portion and at least one adjoining straight portion of circular cross-section, the apparatus comprising means for bending a straight pipe length into a continuous curve and reshaping tool means for subsequent straightening of at least one of the end portions of the pipe length, the tool means comprising a first tool insertable into said end portion to act on the internal surface thereof and a second tool engageable with said end portion at its exterior and adapted to, in use, act thereon over a substantially cylindrical locus.

Embodiments of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings, in which: Eig. 1 shows, in elevation, a pipe bend of uniform cross-section, Fig. 2 shows, in elevation, a pipe bend with straight limbB at both ends, Fig. 3 shows, in section, an apparatus arranged to -4operate stepwise for straightening the pipe ends bymeans of internal rolls, Fig. 4 shows, in section, an apparatus arranged to operate with circularly arranged pressure rollers, Fig..5 shows a section along the line A-B of Fig. 4, Fig. 6 shows an apparatus arranged to operate stepwise for straightening pipe ends by means of a mandrel, Figs. 7 and 8 show, in section and in elevation, respectively, an apparatus with an arcuate abutment and arranged to operate with a mandrel, for straightening pipe ends, Fig. 9 show.s, in section, an apparatus equipped with a movable die and a shaping plate, the die of which has two lug-shaped lateral projections, Fig. 10 shows, in section, an apparatus suitable for the manufacture of short limbs and arranged to operate with a press die, Fig. 11 shows.in elevation, the apparatus illustrated in Fig. 10, Fig, 12 shows in section, a rolling apparatus for producing longer limbs, Fig. 13 shows schematically an automatic drive for the presser rollers for a rolling apparatus, Fig. 14 shows in elevation, a press apparatus equipped with a fixedly built-in die, Fig. 15 shows in full section, a press apparatus provided with a fixedly built-in die, Fig. 16 shows in section, an apparatus suitable for -5pipe bends of any desired cross-section for the production of long or short limbs, Fig. 17 shows in plan view, the apparatus illustrated in Fig. 16, Fig. 18 shows in plan view, an apparatus for the rolling of limbs with subsequent sizing by meane of a mandrel, Fig. 19 shows in elevation, the apparatus illustrated in Fig. 18, Fig. 20 shows parts of the apparatus illustrated in Fig. 18 in partial section along line A-B, Fig. 21 shows in elevation, an apparatus arranged to operate with a spreading mandrel, Fig. 22 shows in section, an apparatus arranged to operate with a spreading mandrel, Fig. 23 shows in plan view, an apparatus suitable for the simultaneous straightening of both pipe ends and arranged to operate with spreading dies, Fig. 24 shows in elevation, a detail of the apparatus illustrated in Fig. 23, Fig. 25 shows in plan view, a detail of the apparatus illustrated in Fig. 23.

Fig. 26 and 27 show a further development of the apparatus shown in Fig. 16.

In a known method for the manufacture of pipe bends, a pipe bend 1 (Fig. l) of a larger pipe diameter and uniform wall thickness is manufactured out of a narrower pipe length. The pipe length is uniformly curved and. enlarged. 6813 -6For the manufacture of pipe bends with straight i. e. tangentially directed cylindrical limbs 2 and 3 (Fig. 2), the pipe bend 1 is subjected to further processing. The deforming operations required for this can be per5 formed in the.cold and in the hot state. To keep the deformation forces small and to avoid cold workhardening, it may be preferable to perform the deformation hot.

The methods· described in detail below proceed from 10 the problem of straightening the ends 4 and 5 (Fig. l) of a pipe bend into a cylindrical shape of uniform cross-section.

In a step method, the straightening of the pipe ends 4 and 5 takes place stepwise. The respective pipe · end 4 and 5 is continuously pressed into the respective tool at a certain rate of advance. Each pipe bend end 4 and 5 must be treated individually. The length of the limb 2 and 3 (Fig. 2) must be considered in the production of the pipe bend 1.

A pipe bend can be straightened in a stepwise manner by the use of pressure rollers which are applied within the pipe bends and which co-operate with a divided, outer mould. In Fig, 3, a device of that kind is illustrated schematically. A pipe bend 13 is pushed in stepwise between two movable shaping cheeks 14 and 15 which briefly open and close. Disposed between the two' shaping cheeks 14 and 15 are rotating pressure rollers 16 and 17, which may for example be constructed alternately as -7working and support rollers and which are driven hy a motor. The pressure rollers 16 and 17 straighten the end 18 of the pipe bend 13 into a cylindrical limb 20 by pressing the end 18 against the cylindrical inner wall surfaces 19 of the shaping cheeks 14 and 15.

In the case of large pipe cross-sections, pressure rollers 21 and 22 may be circumferentially arranged as shown in Pigs. 4 and 5 and may be driven by a motor through a planetary gear 23. A centrally arranged support roller 24, which is adjustable, supports the pressure rollers 21 and 22. Of the two press cheeks 25 and 26, the press cheek 25 is arranged to be movable.

The pipe bend 27 is clamped in between the two press cheeks 25 and 26 and processed by the constantly driven and slowly introduced pressure rollers 21 and 22, the cylindrical shape 28 of the press cheeks 25 and 26 determining the cross-section of the limb.

In the case of particularly narrow pipe crosssections, the device illustrated in Pig. 6 may be used. Two tool cheeks 30 and 31, moving up and down, clamp around the introduced pipe end 32 of a pipe bend 33, into which a mandrel 34 is pushed in stepwise. Thereafter, the tool cheeks 30 and 31 are detached and the mandrel 34 together with the pipe bend 33 is moved a little to the right. Poliowing this movement, the tool cheeks 30 and 31 close anew and the mandrel 34 is pushed in further by the length of advance. This is repeated until the required length of the limb 35 is produced. -8With narrow pipe bends, it is expedient to provide at one of the tool cheeks 36 (Figs. 7 and 8) a semicircular abutment 37 which may be displaceable in height. This abutment 37 supports the bearing inner surface 38 of a curved pipe bend 39 which is straightened by a movable mandrel 40 and a tool cheek 41 which is movable up and down.

With small limbs and small pipe cross-sections, a press tool illustrated in Fig. 9 may be used which performs the straightening deformation suddenly. This press tool comprises a pattern plate 42, for the reception of a pipe bend 43, which is laid on it with the pipe ends pointing upwardly. A die 44 co-operating with the pattern plate 42 at both of its sides has lugs 45 which during pressing act on the outer internal wall surfaces 46 of the pipe bend 43. Shaping zones 48, which exert pressure on the inner external wall surface 49 of the pipe bend 43 during the pressing process are provided in the interior space 47 of the die 44 beside the lugs 45. It can be seen from the left hand part of Fig. 9 that the die 44 is in its open setting and must be moved upwardly far enough for the pipe bend 43 to be laid on and removed from the pattern plate 42. From the right hand part of Fig. 9 it can be seen that the die 44 is in its pressing position in which it has straightened the pipe end 50 into a cylindrical limb 51.

Thick-walled pipe bends 65 which are to have relatively short limbs 66, may be processed by the -9apparatus illustrated in Figs. 10 and 11. The apparatus comprises a locally fixed press cheek 68, a movable press cheek 69 and a movable die 70. The die 70 is inserted into the pipe end 71 to be straightened. Subsequently, the pipe bend 65 is guided by its end 71 and the die 70 between the press cheeks 68 and 69· Straightening takes place by driving the cylindrical press cheeks 68 and 69 together.

Large pipe bends 72 may be processed by rotating pressure rollers. Two pressure rollers 74 and 75 (Fig. 12) act from the outside and engage the outer periphery of the pipe bend 72. The pressure rollers 74 and 75 are arranged on a rotating plate 73 which is driven by a motor. A pressure roller 77, engaging at the inner wall 76 between the two pressure rollers 74 and 75, presses the material to be deformed against the pressure rollers 74 and 75. The pressure rollers 74, 75 and 77 are rotatably journalled on axles 78 to 80 which are fastened in bushes 81 to 83 of the plate 73. The bushes 81 to 83 are rotatably journalled in the plate 73 and arrested in the respectively set position by suitable detent means (not shown). Through the eccentric bearing, the pressure rollers 74, 75 and 77 can be set not only exactly to the wall thickness, but can also be used for the processing of larger pipe bend diameters within a restricted range of adjustment. The pipe bend 72 is expediently fed through a clamping device 85, which is rotatable about an axle 84, the drive 86 of which may take place 6 813 -10automatically. The pressure rollers 74, 75 and 77 can be axially displaced within a restricted range of adjustment by means of the plate 75 or the longitudinally displaceable drive shaft 87 respectively.

The pressure rollers can also have their own drive.

For this, automatically driven pressure rollers 88 to 89 are, as shown in Fig. 15, fastened to shafts 90 and 91 journalled in a rotatable plate 92, in adjustable eccentric bushes 9·5 and 94 which permit a slight dis10 placement. Specially toothed spur gears 95 and 96, which mesh with each other, are disposed on the shafts 90 and 91. The spur gear 96 meshes with a spur gear 98 fastened to a hollow shaft 97· Fastened to a hollow · shaft 97 is a further spur wheel 99 which meshes with a spur wheel 101 disposed on a drive shaft 100. The hollow shaft 97 is disposed on a shaft 102 which carries the plate 92 and is set into motion from the drive shaft 100 through a gear train.

The peripheral speeds of the pressure rollers 88 and 89 and of the plate 92 are easily adapted to the respective conditions by the transmission ratios of the spur gears.

Extremely long limbs can be produced by the apparatus illustrated in Figs. 14 and 15.

This apparatus comprises a tool cheek 103 which is locally fixed and which co-operates with a movable tool cheek 104. The tool cheeks 103 and 104 have semicircular press profiles 105 and 106, which in connection -11with a semi-circular die 107, the bearing arm 108 of which is rigidly fastened to the tool cheek 104, straighten a portion 109 of a pipe bend 110.

For producing smaller or larger limbs an apparatus 111 illustrated in the Figs. 16 and 17 is also suitable. This apparatus 111 comprises a two-part clamping cheek 112 in which a pipe bend 113 is laid and clamped fast. The clamping cheek 112 is pivotable about an axle 114 by an arm 115 which is actuable by an hydraulic drive 116. The axle 114 is located in a bearing eye 117 of a press tool 118 which is locally fixed and equipped with a bearing plate 119, on which is disposed a stationary semi-circular mandrel 120 which protrudes into a cylindrical bore 121 of the press tool 118, at the inside of which is out on a deformation block 122 having a semi-circular cut out. A protruding section 123 of the pipe bend 113 is drawn over the mandrel 120 during the pressing process and straightened out cylindrically by the deformation block 122 or the cylindrical bore 121 of the press tool 118.

For the production of longer limbs, a roll apparatus illustrated in the Figs. 18 to 20 can be used. This apparatus comprises a fixed clamping cheek 124 which is divided and serves for clamping a pipe bend 125. A pressure roller 127 is moved by suitable transport means from an initial position shown in Fig. 20 rectilinearly in the direction to the pipe end. The pressure roller 127 co-operates with a fixed counter-holder groove -12>, 128 and presses the curved pipe portion 126 straight during rolling. In the end position of the pressure roller 127, a reotilinearly guided mandrel 129, which is required for the internal sizing and for the accurate alignment of the limb, is pushed into the limb thus produced.

For bends of large size, which have a somewhat large wall thickness, an apparatus illustrated in Figs. 21 and 22 is suitable and comprises a fixed clamping cheek 130, a movable _clamping cheek 131 as well as of an axially movable spreading mandrel 132 having spreading segments 133. The portion 134 to be straightened of a pipe bend 135 is inserted between the clamping cheeks 130 and 131 and the spreading mandrel 132 is then pressed in. The afore-described arrangement is suitable particularly for the simultaneous production of a limb at both- ends of a pipe bend.

As can be seen from Figs. 23 to 25, a pipe bend 135 is firmly clamped at its ends 136 and 137 into two clamping cheek pairs 138 to 141 which are arranged at right angles or in another adjustable angular setting to each other. One of the clamping cheeks 139 or 141 is movably arranged and the other 138 or 140 is fixed. The spreading mandrels 142 or 143, displaceable trans25 versely of the clamping cheek pairs 138 to 141, are during straightening pressed simultaneously into the openings of the pipe bend 135 and thereby produce the two limbs in co-operation with the clamping cheek pairs 6 813 -13138 and 139 or 140 and 141.

The apparatus illustrated in Figs. 26 and 27 makes the simultaneous manufacture of a limb at both ends of a pipe bend possible. This apparatus comprises a fixed, two-part clamping cheek 171 and 172, into which a pipe bend 173 is laid and clamped fast. Press tools 175 and 176 are arranged on a respective arm which is pivotable about an axle 174 by respective hydraulic drives 177 and 178. These preBS tools each comprise a semi-circular mandrel 179 and 180 and deformation blocks 181 and 182 having a semi-circular cut out. On the upward pivotation of the press tools, the protruding sections of the pipe bend 173 are drawn over the mandrels 179 and 180 and shaped cylindrically by the deformation blocks 181 and 182.

The embodiments described above by way of example eliminate the discussed disadvantages of known methods for the manufacture of pipe ends with welded-on pipe stubs.

A completely new product can be manufactured at significantly lower costs than the hitherto produced pipe bends with welded-on stubs.

Claims

1. WHAT WE CLAIM IS :1. A metho'd of producing a bent pipe length having a diameter greater than that of the straight pipe length and comprising a bent portion and. at least one adjoining straight 5 portion of circular cross-section, the method comprising the steps of bending the straight pipe length into a continuous curve and subsequently straightening at least one of the end portions of the pipe length by reshaping tool means engaging said at least one end portion and acting thereon 10 over a cylindrical work region.

2. A method as claimed in claim 1, wherein the tool means comprises die means and the step of straightening comprises forging said at least one end portion in the die means. 15

3. · A method as claimed in claim 1, wherein the tool means comprises die means and the step of straightening comprises pressing said at least one end portion « in the die means. .

4. Apparatus for producing a bent pipe length 20 having a diameter greater than that of the straight pipe length and comprising a bent portion and at least one adjoining straight portion of circular cross-section, the apparatus comprising means for bending a straight pipe length into a continuous curve and reshaping tool means for subsequent straightening of at least one of the end portions of the pipe length, the tool means comprising a first tool -15insertable into said end portion to act on the internal surface thereof and a second tool engageable with said end portion at its exterior and adapted to, in use, act thereon over an at least part cylindrical locus.

5. Apparatus as claimed in claim 4, wherein the second tool comprises two members which are provided with half-cylindrical support surfaces and which are movable towards each other to engage the external surface of said end portion, and the first tool comprises rotatable pressure rollers mounted in a stationary location between said members and engageable in said end portion.

6. Apparatus as claimed in claim 5, wherein the pressure rollers are arranged in a circle and are drivable by a common drive means.

7. Apparatus as claimed in claim 6, wherein the pressure rollers are displaceable around the circle and are supported by and co-operable with a common support roller.

8. Apparatus as claimed in claim 4, wherein the second tool comprises two clamping members one of which is movable towards the other to clamp said end portion therebetween, and a mandrel insertable in steps within said end portion while clamped between the clamping members.

9. Apparatus as claimed in claim 8, comprising an arcuate abutment provided on said other clamping member for supporting the pipe length. 4 6 813 -Ιβ10. Apparatus as claimed in claim 4, wherein the second tool comprises a stationary support member having a support surface corresponding in shape to the shape of the bent portion of the pipe length, and the first tool comprises shaped protruding press elements directed towards said support surface and each adapted to press against an inner wall surface portion of a respective one of the end portions of the pipe length. 11. Apparatus as claimed in claim 4, wherein the second tool comprises a stationary and a movable member for receiving said end portion therebetween and the first tool comprises a die insertable in said end portion, the movable member being displaceable towards the stationary member to effect straightening of said end portion. 12. Apparatus as claimed in claim 4, wherein the first and second tools comprise at least one outer pressure roller and at least one inner pressure roller which is adapted to engage inner and outer wall portions, respectively, of said end portion and which are movable around the wall portions by a rotatable plate. 13. Apparatus as claimed in claim 12, wherein said inner and outer pressure rollers are so mounted to the plate as to be rotatable about axes arranged at an adjustable spacing. 14. Apparatus as claimed in either claim 12 or 13, comprising drive means to rotationally drive the pressure rollers. -1715. Apparatus as claimed in any one of claims 12 to 14, wherein the pressure rollers and the rotatable plate are driven by a common drive means. 16. Apparatus as claimed in claim 4, wherein the second tool comprises a stationary and a movable member each provided with a semicircular support surface for engagement with the external surface of said end portion, and the first tool comprises a die provided with a semicircular support surface engageable with the internal surface of said end portion, the die being rigidly mounted on said movable member. 17. Apparatus as claimed in claim 4, wherein the first tool comprises straightening means and the second tool comprises clamping means for clamping the pipe length, the clamping means being pivotable about a stationary axis to press said end portion into the straightening means. 18. Apparatus as claimed in claim 4, wherein the second tool comprises a support member provided with a groove for receiving said end portion, stationary holding means for holding the pipe length against the support member, and a pressure roller engageable with said end portion and displaceable parallel to the groove to straighten the end portion, the first tool comprising a bore-sizing mandrel insertable into said end portion. 19. Apparatus as claimed in claim 4, wherein the second tool comprises a stationary and a movable member adapted to clamp said end portion therebetween, and the -18ι ' first tool comprises a mandrel which is insertable into said end portion and expandable to press against the internal surface thereof. 20. Apparatus as claimed in claim 19, comprising 5 two such second tools disposed in a selectable relationship to each other and each adapted to straighten a respective end portion of the pipe length, and two such first tools each associated with a respective one of the second tools.

10. 21. An apparatus for producing a bent pipe substantially as hereinbefore described with reference to Fig. 3, Figs. 4 and 5, Fig. 6, Figs. 7 and 8, Figs. 10 and

11. , Fig.

12. , Fig.

13. , Figs.

14. And 15, Figs. 16 and 16, Figs. 18 to 20, Figs. 21 and 22, Figs. 23 to 25,

15. Or Figs. 26 and 27.