US3845650A - Machine for manufacturing a coil of a pipe by bending it - Google Patents

Machine for manufacturing a coil of a pipe by bending it Download PDF

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US3845650A
US3845650A US32519673A US3845650A US 3845650 A US3845650 A US 3845650A US 32519673 A US32519673 A US 32519673A US 3845650 A US3845650 A US 3845650A
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Prior art keywords
pipe
means
machine
clamp
bending
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V Gurevich
V Ryabokobylenko
E Moshnin
S Yanov
B Romanov
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B Romanov
E Moshnin
V Gurevich
S Yanov
V Ryabokobylenko
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B21MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21DWORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D11/00Bending not restricted to forms of material mentioned in only one of groups B21D5/00, B21D7/00, B21D9/00; Bending not provided for in groups B21D5/00 - B21D9/00; Twisting
    • B21D11/06Bending into helical or spiral form; Forming a succession of return bends, e.g. serpentine form
    • B21D11/07Making serpentine-shaped articles by bending essentially in one plane

Abstract

The present invention relates to equipment for manufacturing heat exchange apparatus and more particularly to a machine for manufacturing a coil of a pipe by bending it by means of movable clamps. The invention ensures the manufacturing of a coil with bends whose radius as measured from the central axis of the pipe is within the range of from 0.8 to 1.5 of the outside diameter of the pipe, which is due to an improvement of the bending mechanism and its substantial simplification by dispensing with the master form. The coil is formed in a horizontal plane, with the position of the longitudinal axis of the pipe being bent remaining unchanged and without rotating the pipe about its axis.

Description

omanov et a1.

tet [1 1 1451 Nov. 5, 1974 MACHINE FOR MANUFACTURKNG A COlllL OF A PIPE BY EENDHNG 117 [22] Filed: Jan. 19, 1973 [21] Appl. No.: 325,196

[52] US. C1. 72/310, 72/316, 72/318,

72/342, 72/D1G. 16, 140/71 R [51] Int. Cl. 321d 111/07- [58] Field of Search 72/144, 217, 218, 342,

72/296-298, 308-310, 316, 318, DIG. l2, DIG. 16, 307; 29/157.3 R; 113/118 R;

[5 6] References Cited UNlTED STATES PATENTS 2,316,049 4/1943 Connor ..72/217 2,345,102 3/1944 Dick 2,453,868 11/1948 Shaw,.|r. 2,454,290 11/1948 Payne ..72/144 5 3 "M1,; 7 50 L i 47 45 2,535,328 12/1950 Somerville 72/217 2,565,940 8/1951 Armstrong et a1 72/D1G. 16 2,582,576 1/1952 Zweyer 72/183 X 3,406,551 10/1968 Coody 72/166 3,407,850 10/1968 Kelm 72/702 X 3,742,749 7/1973 Bondarenko 72/217 FOREIGN PATENTS OR APPLICATIONS 2,057,227 1971' France 72/342 630,232 10/1949 Great Britain 72/342 7 Primary Examiner-Charles W. Lanham Assistant ExaminerD. M. Gurley Attorney, Agent, or Firm--Waters, Roditi, Schwartz & Nissen [5 7] ABSTRACT The present invention relates to equipment for manufacturing heat exchange apparatus and more particularly to a machine for manufacturing a coil of a pipe by bending it by means of movable clamps. The invention ensures the manufacturing of a coil with bends whose radius as measured from the central axis of the pipe is within the range of from 0.8 to 1.5 of the outside diameter of the pipe, which is due to an improvement of the bending mechanism and its substantial simplification by dispensing with the master form. The coil is formed in a horizontal plane, with the position of the longitudinal axis of the pipe being bent remaining unchanged and without rotating the pipe about its axis.'

13 Claims, 12 Drawing Figures O 5 .6. Q K .3 & 3 St S a a Q k V QR S TAM NR M N SE Q v m NW v fi m Jm /& H & m w f m Q J::::::.:. m S v w ill m //,/./14/a4r'a,'r4 %N WW. g Y Q wmkmba w M Q 7 w a Q PATENTEMuv 5 W PATENTEHNHV 51914 3.845550 Y SHEET ESP 8 PATENTEUNuv 51914 3845650 saw so? a PATENTEDIBV m 38456350 SHEEI 7 OF 8 FIG. I!

MACHINE FOR MANUFACTURHNG A COHL UP A PIPE BY BENDHNG IT The present invention relates to equipment for manu-,

facturing heat exchange apparatus and more particularly to a machine for manufacturing a coil of a pipe by bending it by means of movable clamps.

The invention may be the most advantageously used in manufacturing tubular heating surfaces of boilers. Furthermore, the. invention may find application in manufacturing heat exchange apparatus for the chemical and oil industry, as well as in the ship building.

The attempts to make a coil of a relatively long pip'e by bending the latter in the cold state about a master form are widely known. These attempts are associated with the use of a slewing table mounted on the base of a machine and supporting a master form and a clamp. Mounted on the slewing table is also a clamping slider adapted to urge the pipe against said master form. Upon fixing the pipe in the clamp the slewing table is rotated, and the pipe is bent about the master form while simultaneously being moved so as to follow the clamp. Due to friction forces created between the pipe and the clamping slider the latter moves following the pipe thus withstanding reaction forces arising during thebending. After a bend has been formed the pipe is released from the clamp, moved in the axial direction up to a point of formation ofthe next bend and rotated at 180 about its longitudinal axis. Then the bending is effected in the same order and in the same direction as described above. Asthe coil making proceeds, it besliders, as well as relative movement of these devices are associated with the employment of complicated mechanisms which considerably increase the cost of the machine and make its operation more difficult. Major difficulties arise in the case, where it is required to make coils of pipes having different diameter on the same machine. In such cases it is necessary to replace the master form, both clamping sliders and the jaws of comes more and more difficult to rotate the pipe at e 180 for making the next bend.

This embodiment of the machine permits to dispense with the step of rotating the coil at 180 after the formation of the next bend. it is sufficient to release the clamp and the clamping slider, and to lower the master form and said clamp. Then the master form is shifted to the other side with respect to the longitudinal axis of the pipe, the position of the pipe remaining unchanged, the master form and the clamping slider are lifted up to a level of the pipe and moved close to the pipe. The formation of the next bend is effected by bending the pipe in the direction opposite to that selected for the preceding bend.

During the movement of the coil in the horizontal plane the latter is based on a support performing the rotations synchronously with this coil. Thus, the manufacturing of the coil is substantially simpler, but certain difficulties restricted the filed of application of this machine. First of all, this is associated with the fact that the bends of relatively small curvature can be formed in the above-described machine only by means of a mandrel which cannot be used in manufacturing a coil.

At the same time, complicated movements of the master form together with the clamps and the clamping the clamps.

It should be also noted that the bends having relatively snall bending radius, which are obtainable on known machines, are characterized by elevated ovality of the cross section, whereby reliability and durability of the coils are reduced.

It is the main object of the invention to provide a machine for manufacturing a coil of a pipe by bending it in which the bending mechanism is substantially simplified and which is provided with devices substituting the master forms.

The above object is accomplished by that in a machine for manufacturing a coil of a pipe by bending it comprising a bending mechanism having a slewing table supporting a pair of clamps for a pipe and capable of performing-additional movement transversally relative to the axis of the pipe being bent according to the invention there is provided means for axially moving the pipe towards the bending mechanism, the pair of clamps being mounted in such a manner that a gap defined by a pair of jaws in one clamp be coaxial with similar gap in the other clamp, and there is also provided means for raising movable parts which carry the jaw in each of said clamps. Mounted between the clamps is heating means fixed to stationary base, the tube being fed towards said means afterleaving a guiding sleeve mounted adjacent said heating means. In this embodiment of the machine aportion of the pipe being bent and heated up to a degree, at which the plasticity of metal is substantially increased, can be readily bent, the adjacent cold portions of the pipe performing the functions of a mandrel, while the clampsand the guiding sleeve functioning as the'master form and the clamping sliders. The arrangement of the clamps and heating means is such that upon forming one bend and prior to the formation of another one, it is possible to position the next clamp, which is to be put in operation, behind heating means in the direction of the axial movement of the pipe.

Means for axially moving the pipe is adapted to impart to the pipe during the bending a speed which is higher than the speed of movement of the clamps of the bending mechanism. In this case axial compression of the pipe takes place, whereby the reduction of the thickness of the pipe wall in the zone of the bend is eliminated. Bonds and straight portions of the coil will be of equal strength.

According to a preferable embodiment of the invention it is advantageous that means for axially moving the pipe comprise a slider with a clamp mounted in straight guides made in the stationary base, two screws symmetrically arranged with respect tothe clamp cooperating with the slider, said screws being connected to a motor via a gear train. In this case the forces applied to the screws are uniformly distributed thereby increasing service life of the mechanism.

It is advantageous to mount the slewing table in a holding ring having eyes for passing therethrough parallel rods fixed to the stationary base. In this case said holding ring is preferably connected to an actuating cylinder adapted to move the holding ring along said rods. The slewing table is of circular shape, whereby reaction forces appearing during the bending are distributed over relatively large surface.

In order to ensure the adjustment of the machine for a required bending radius, is advantageous to provide adjusting movable stops on the stationary base adjacent the ends of said rods for limiting the movement of the housing along the rods. I

In order to ensure the control of said adjusting movable stops it is advantageous to fix the ends of said rods to the stationary base by means of bushings disposed in holes appropriately made in said base, while the end of each bushing which faces the housing should be provided with a threaded portion co-operating with the adjusting movable stop which comprises a nut and have teeth along its peripheral surface, said teeth being in meshing engagement with a gearconnected to a mechanical transmission.

Synchronous movement of the adjusting movable stops disposed adjacent one and the same rod can be accomplished in the case, where the bushings located adjacent the ends of said rod have oppositely directed threads. In this case the gears fixed on one and the same shaft are in meshing engagement with the adjusting movable stops co-operating with these bushings.

In order to provide for uniform distribution of a load between the adjusting movable stops, it isadvantageous that the shafts carrying the gears be interconnected by means of a mechanical transmission adapted to impart rotation to all the shafts synchronously.

During the change of position of the adjusting movable stops it is necessary to adjust the position of the clamps on the slewing table in order that the gap between the jaws in each clamp be coaxial with the pipe being bent in the starting position, when adjusting the machine for a new bending radius. For this purpose it is expedient to provide straight guides on the slewing table in which a slider should be mounted, said slider carrying said pair of clamps and being connected to means for moving said slider along said guides. In this case the guides should be arranged transversally relative to the gap between the clamp jaws.

The most simple structure of the clamps of the bending mechanism is obtained in the case, where their jaws are brought together only in the uppermost position, while remaining spaced apart in any other position. In order to do this, it is desirable that said movable parts carrying the jaws of each clamp in the bending mechanism comprise two double-arm levers joined by means of a common hinge loaded by springs which bear against said slider. In this case one identical ends of these levers should support a pair of the jaws, the other identical ends of said levers should be interconnected by means of a common hinge connected to an actuating cylinder, while the upward movement of said firstmentioned hinge should be limited. The limitation of the upward movement of said hinge results in that at some instant during the movement of the piston rod of the actuating cylinder upwards after the hinge movement has been stopped, the actuating cylinder spaces apart the lower ends of the double-arm levers, and the jaws are brought together, whereby the pipe is fixed-in the clamp. During the downward movement of the piston rod of the actuating cylinder the jaws are spaced apart and remain in this open position until complete lowering.

In order to the most completely utilize the capacity of means for axially moving the pipe, it is advantageous to connect the slewing table to the motor for rotating it by means of a self-braking worm gear, the worm wheel crown of said gear being preferably mounted on the slewing table. During the bending a required force will be created by means for axially moving the pipe under conditions of the eccentric arrangement of the clamps with respect to the axis of rotation of the slewing table. In this case the power of the slewing table motor is consumed only for releasing the worm gear from the braking conditions.

In order to ensure permanent connection between the self-braking worm gear and the motor during the movement of said holding ring along the rods, it is advantageous to provide on the worm shaft of said gear a spur gear which is in meshing engagement with another spur gear connected to the motor, the width of the gear corresponding to the amount of movement of the slewing table transversally relative to the pipe being bent.

The reduction of the thickness of the pipe walls in the zone thereof being bent during the formation of a bend can be eliminated, if the motor of means for axially moving the pipe and the motor performing the rotation of the slewing table comprise electric motors, said motors being coupled by means of an electric circuit to a regulator of the ratio between the rotational speeds of these motors.

The coil can be the most conveniently supported during its manufacturing in the case, where the rods, along which the holding ring moves, are horizontally arranged.

Substantial advantage of this invention consists in that the machine ensures'the manufacturing of a coil with bends, whose radius as measured from the central axis of the pipe is within the range of from 0.8 to 1.5 of the outside diameter of the pipe, the reduction of the thickness of the pipe within the zone of the bent portion of the pipe not exceeding 0-20 percent depending upon the ratio between the thickness of the pipe wall and the outside diameter thereof. An amount of the thickness reduction is predetermined based upon the requirement of elimination of the formation of undulations on the inner side of the wall of the bent portion.

A specific embodiment of the invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 shows a diagrammatic plan view of the machine partially in section;

FIG. 2 is an enlarged cross sectional view taken along the line II-II in FIG. 1;

FIG. 3 is an enlarged cross sectional view taken along the line IIIIII in FIG. 1;

FIGS. 4 to 9 show the positions of the slewing table with the clamps and the holding ring during the manufacturing of a coil in a reduced scale;

FIG. 10 is an enlarged diagrammatic view of the clamp of the bending mechanism during the holding of the pipe;

FIG. 11 shows an enlarged view of the clamp in the position in which its jaws are spaced apart;

FIG. 12 shows an enlarged view of the clamp in the lowermost position.

The machine for manufacturing a coil of a pipe 1 (FIGS. 1 and 2) comprises a holding ring 2 with eyes 3 accommodating bronze sleeves 4. Round steel rods 5 extend through the eyes 3. The endsof the rods 5 are received in steel bushings 6 fixed by means of bolts (not shown) in holes appropriately made in a stationary base plate of the base. The holding ring 2 is connected to a piston rod 8 of a pneumatic actuating cylinder 9 attached to the base 7. The actuating cylinder 9 imparts to the holding ring 2 a movement along the rods 5 supportingthis ring prior to the formation of each bend. In this case the rods 5 and the-piston rod 8 of the actuating cylinder 9 are disposed tranversally relative to the pipe 1. The holding ring 2 supports a slewing table 10, a bronze sleeve 11 beingpress fitted into the holding ring 2 in order to reduce friction between the tableand the holding ring.

The lower part of the slewing table is provided with a worm wheel crown l2 meshing with a worm 13 mounted in bearings 14 received in holes made in an appropriate manner in the holding ring 2. Fixed on one and the same shaft with the worm 13 is a spur gear 15 which is in meshing engagement with a spur gear 16 mounted in bearings 17 fixed to the base 7. The shaft of the gear 16 isconnected to an electric motor 18 via a reduction gear 19 and a coupling 20. The meshing engagement of the worm 13 with the worm wheel crown 12 is made so as to be self-braking. The electric motor 18 is adaptedto continuously effect release of the engagement at a required speed during the bending, whereby the slewing table 10 which is subjected to an axial force applied to the pipe 1, will rotate at a speed directly proportional to the speed of release. The slew- 1 ing table 10 is provided with a groove 21 accommodating a slider 22 having lateral projections 23 received in guiding slots 24 of the lateral walls of the table 10 which define the groove 21. The groove 21 is arranged radially relativeto the axis AA of rotation of the slewing table 10. The slider 22 is connected to a screw 25 which engages a threaded portion of the walls of a hole 26 provided in a projection 27 of the slewing table 10. The screw 25 is rotated by means of handwheel 28 during the adjustment of the machine for a desired bend radius of a coil. The slider 22 is provided with two recesses 29 accommodating clamps 30 with the jaws. The jaws are so arranged in the clamps 30 that a gap defined by the jaws in one clamp is coaxial with similar gap in the other clamp. Each clamp 30 is provided with means 31 comprising a pneumatic cylinder which is adapted to raise and lower the pair of jaws while bringing them together and apart respectively. p

' The slewing table 10, the clamps 30 and the holding ring 2 are the main assemblies of a bending mechanism 32. The pipe 1 is fed towards the bending mechanism 32 by means 33 (FIGS. 1 and 3).for axially moving this pipe, that is for moving the pipe 1 along the longitudinal axis BB thereof. Means 33 for axially moving the pipe comprise a slider 34 mounted by means of guiding projections 35 in guiding slots 36 made in a lateral part 37 of the base 7. In order to reduce friction during the movement of the slider 34 along the guiding slots 36 the latter accommodate bronze inserts 38. The intermediate part of the slider is provided with a recess 39 accommodating a clamp 40 with the jaws to receive the pipe 1. The clamp 40 is controlled by means 41 comprising a pneumatic cylinder. The upper part of the slider 34 is provided with two recesses 42 symmetrical with respect to the clamp 40 accommodating rectangular nuts 43. The nuts 43 co-operate with screws 44 mounted in bearings 45 disposed in holes appropriately made in the base 7 and in its lateral part 37. The screws 44 are connected to spur gears 46 which are in meshing engagement with a spur gear 47. The spur gear 47 is adapted to impart rotation to the screws 44 from an electric motor 48 connected to this spur gear via a coupling 49 and a reduction gear 50.

During the movement of the pipe 1 the position of its longitudinal axis BB in space remains unchanged. The pipe 1 is supported by a guiding sleeve 51 (FIGS. 1 and 2) rigidly secured to the base 7 by means of a bracket 52. Mounted behind the guiding sleeve 51 in the direction of movement of the pipe 1 is an electric inductor 53 connected to an electric transformer 54 by means of electric bars 55 (only one bar is shown). The longitudinal axis of the inductor is aligned with the longitudinal axis BB of the pipe 1. The transformer 54 is fixed to the base 7.

The bend radius is set prior to the manufacturing of a coil by changing the position of adjusting movable stops 56 (FIG. 1) which comprise nuts and have straight teeth on the peripheral surface. The stops 56 are provided with threaded holes by means of which each of these stops co-operates with threaded portions made at the ends of the bushings 6 extending inside the base 7, said bushings receiving said ends of the rods 5. The teeth of the stops 56 co-operate with the teeth of spur gears 57 mounted on shafts 58. These shafts 58 are mounted in bearings 59 received in holes appropriately made in the walls of the base 7. The both shafts 58 rotate synchronously due .to their interconnection by means of a shaft 60 mounted in bearings 61 transversally relative to the shafts 58 and bevel gears mounted on said shafts 58 and 60. Rotation is imparted to the shafts by means of a hand-wheel 63 fixed to one of the shafts 58. i

The direction of the thread in the stops 56 is selected so that depending upon the sense of rotation of the handwheel 63 these'stops could be brought together or apart in each pair of them. The distance between these stops determines the amount of eccentricity e, that is the distance between the axis AA of the slewing table 10 and the longitudinal axis BB of the pipe 1. The bend radius of a coil accurately corresponds to the amount of eccentricity.

In the starting position of the bending mechanism the holding ring 2 (FIG. 4) is retracted and bears against the stops 56. In this position the clamps 30 are arranged along the axis BB, and in the left hand one of these clamps the jaws are spaced apart and lowered below the pipe. The jaws of the right hand clamp are raised and clamp the pipe (FIG. 2). Then the inductor 53 is energized together with means 33 for axially moving the pipe (FIGS. 1 and 3), and the worm gear is released by rotating the worm13. Under the action of a force applied to the pipe in the direction of an arrow C the slewing table 10 begins to rotate due to the presence of the arm creating torque. The portion of the pipe, in which a bend is formed, gradually passes through the inductor 53, is being'heated and simultaneously bent, the slewing table 10 at the same time rotating in the direction of an arrow V. The portion of the pipe to be bent which is heated to a degree at which metal plasticity is materially increased, can be readily bent, the adjacent cold portions of the pipe 1 performing the functions similar to the functions of a mandrel in known machines, whereas the clamp 30 and the sleeve 51 perform the functions of the master form of the clamp and of the clamping sliders.

Upon rotation of the slewing table 10 through 180 (FIG. a coil bend is formed. The inductor 53 is deenergized, the pipe 1 is released from the clamp 30 (FIG. 6) holding it during the rotation of the table 10, and the pipe is moved in the direction of an arrow C under the action of an axial force applied to the pipe 1 until the next portion of this pipe to be bent is brought close to the inductor 53. At the same time the holding ring 2 is shifted in the direction of an arrow D (FIG. 6) by means of an actuating cylinder 9 (FIG. 1) until it bears against the stops 56 (FIG. 7). Then the pipe 1 is gripped by the clamp 30 disposed on the left side from the inductor 53, the inductor 53 is energized, means 33 for axially moving the pipe is energized, and the pipe begins to be bent under the action of a force applied along the arrow C as a result of rotation of the slewing table in the direction of an arrow W. The second bend of a coil is thus formed (FIG. 8). The inductor 53 is again deenergized, the pipe is released from the clamp, and means for axially moving the pipe moves the latter in the direction indicated by the arrow C (FIG. 9) until the next portion of the pipe to be bent is brought close to the inductor 53. Then the actuating cylinder 9 is energized (FIG. 1), and the holding ring 2 is retracted in the direction indicated by an arrow M (FIG. 8). Subsequently the clamp, the inductor, the bending mechanism and means for axially moving the pipe operate in the above-described order.

An important role is performed in the operation of the bending mechanism 33 (FIGS. 1 and 2) by the clamps 30 which ensure the formation of the coil bends on both sides from the longitudinal axis of the pipe. The movable parts of each of these clamps comprise two double-arm levers 64 (FIGS. 10, 11 and 12) having jaws a at the upper ends thereof. These levers have a common hinge mounted on a cross bar 66. This cross bar is rigidly secured to the upper ends of bolts 67 passed through holes 68 of theslider 22. The lower end of each of the bolts 67 is provided with a nut 69 and a locking nut 70.

The nuts 69 limit the upward movement of the cross bar 66 under the action of compressed springs 71 disposed between the cross bar 66 and the horizontal portion of the slider 22. The lower ends of said double-arm levers are connected with links 72 by means of hinges 73. Said links 72 have a common hinge 74 by means of which these links are connected to a piston rod 75 of a pneumatic cylinder of means 31.

With the cylinder of means 31 being deenergized, the cross bar 66 moves upwards under the action of the compressed springs 71 until the nuts 69 bear against the horizontal portion of the slider 22. Then the cylinder of means 31 is actuated, and the piston rod 75 of this cylinder moves upwards in the direction indicated by an arrow E (FIG. 10), the lower ends of the doublearm levers are spaced apart, and the pipe 1 is clamped between the jaws a of these levers. This position corresponds to the position taken by the assemblies of the machine shown in FIGS. 1, 2, 3 and 4.

Upon the formation of the first bend (FIG. 5) of a coil, the piston rod 75 of the pneumatic cylinder of means 31 moves downwards as indicated by an arrow K (FIG. 11), the lower ends of the double-arm levers 64 are brought together, and the pipe 1 is released from the clamp 30. During further downward movement of the rod (FIG. 12) the cross bar 66 is also involved in the movement. The resistance of the springs 71 is overcome, and the jaws a of the clamp 30 are lowered together with the double-arm levers 64, whereby the rotation of the pipe during the formation of the next bend will not be prevented. The position of the parts of the clamp 30 shown in FIG. 12 corresponds to the position of the assemblies of the machine shown in FIG. 6.

The clamp 40 of FIGS. 1 and 3 of means 33 for axially moving the pipe 1 differs from the clamp 30 of the bending mechanism only in that the former do not have a cross bar and bolts connected to that cross bar, as well as there are no springs. During the periodical movement of the slider 34 the clamp 40 holds the pipe 1 only during the movement of said slider towards the bending mechanism 32.

If there is no correspondance between the speeds of means 33 for axially moving the pipe (FIG. 1) and of the motor 18 performing the rotation of the slewing table 10, the pipe walls thickness may be reduced within the portion being bent.

In order to eliminate this possibility, the electric motor 48 of said means 33 and the electric motor 18 are coupled to a regulator of the ratio between the rotational speeds of these motors by means of an electric circuit 77. The regulator 76 is supplied from an AC network 78.

The above-mentioned ratio between the speeds is selected in such a manner that a speed exceeding the circumferential speed of movement of the clamp 30 of the bending mechanism 32 be imparted to means 33 for axially moving the pipe during the bending. Accordingly, an axial compression of the pipe 1 is created thereby eliminating the reduction of the wall thickness of this pipe 1 within the zone of the bend. The bent and straight portions of the coil are of equal strength.

Reaction forces appearing during the axial compression ofthe pipe 1 are uniformly distributed between the screws 44 of means 33 for axially moving the pipe due to symmetrical arrangement of these screws with respect to the line of application of this force, whereby service life of said means is increased.

The slewing table 10 is of circular shape, whereby the reaction forces appearing during the bending are distributed over relatively large surface.

The machine is readily adjustable for this or another bending radius by changing the position of the stops 56. If a pipe of a diameter different from that for which the machine has been adjusted is to be fed into the machine, it is sufficient to replace the guiding sleeve 51, the electric inductor 53 and the jaws a of the clamps 30 and 40.

What is claimed is:

1. ,A machine for manufacturing a coiled pipe by bending the latter, comprising: a turntable rotating alternately clockwise and anticlockwise under the action of said pipe and adapted to effect additional movement at right angles to the longitudinal axis of said pipe; means for imparting said additional movement to sai turntable in two mutually opposite directions; at least two clamps having jaws being provided on said turntable and mounted so that a gap formed by a pair of jaws in one said clamp is in coaxial alignment with a similar gap of the other clamp while the machine is inoperative, said clamps being adapted to alternately engage said pipe after each rotation of said turntable; means in each of said clamps for raising and lowering movable parts thereof carrying the jaws; means for braking the rotational speed of said turntable, said last-mentioned means together with said turntable, said means for moving the turntable at right angles to the longitudinal axis of the pipe, and said clamps, forming a bending mechanism; heating means mounted on a stationary base between said clamps and adapted to heat said pipe in the zones of formation of the U-bends of the coil; a guiding sleeve mounted on said stationary base adjacent said heating means and adapted to facilitate passage there-through of said pipe toward said heating means while concurrently absorbing reaction forces produced by the bending of said pipe; means for moving said pipe along its longitudinal axis toward said bending mechanism and interacting with said means for braking the rotations of said turntable in response to the action of said means for axially moving said pipe, the latter means imparting motion to said turntable through the medium of said pipe due to the latter being fixed in one of said clamps; said pipe being bent in response to successively fixing said pipe in one of said clamps on said turntable, heating said pipe in the zone of formation of the future U-bend, moving said pipe along its longitudinal axis by said means for its axial movement and braking said turntable by said braking means as this table rotates under-the action of said means fol-moving said pipe along its longitudinal axis, said turntable being rotated through the medium of this pipe and the braking of the table being necessary in order to build up the required axial compression of said pipe so as to prevent or reduce the thinning of its walls in the zone of formation of said U-bend; after completin g the formationof this U-bend and releasing said pipe from said clamp, shifting said turntable at right angles to the longitudinal axis of said pipe and then advancing the latter toward said bending mechanism and fixing it in the other clamp, whereupon all said operations are resumed in the above-described succession.

2. A machine according to claim 1, wherein said means for axially moving said pipe comprise a slider having a clamp and mounted in straight guides made in said stationary base, said slider co-operating with two screws which are symmetrically arranged with respect to said clamp, said screws being connected to a motor by means of a gear train.

3. A machine according to claim 1, wherein said slewing table is mounted in a holding ring having eyes through which parallel rods extend, said rods being fixed to said stationary base, and said holding ring being connected to an actuating cylinder adapted to move the ring along said rods.

4. A machine according to claim 3, wherein adjusting movable stops are provided adjacent the ends of said rods on said stationary base which are adapted to limit the movement of said holding ring along said rods.

A machine according to claim 4, wherein the ends of said rods are fixed to said stationary base by means of bushings received in holes appropriately made in said base, the end of each bushing which faces said holding ring being provided with a threaded portion cooperating with the adjusting movable stop which comprises a nut having teeth on the peripheral surface thereof, said teeth being in meshing engagement with a gear connected to a mechanical transmission.

6. A machine according to claim 5, wherein said bushings disposed adjacent the opposite ends of one and the same rod of said rods have oppositely directed threads, said adjusting movable stops co-operating with said bushings being in meshing engagement with gears mounted on one and the same shaft.

7. A machine according to claim 6, wherein said shafts carrying said gears are interconnected by means 9. A machine according to claim 8, wherein said movable parts carrying said jaws of each of said clamps in said bending mechanism comprise two double-arm levers joined by a common hinge which is loaded by springs which bear against said slider, said levers carrying a pair of said jaws at one identical ends thereof,

while the other identical ends of these levers being interconnected by means of links having a common hinge which is connected to an actuating cylinder, the upward movement of said first-mentioned common hinge being limited.

10. A machine according to claim 1, wherein said slewing table is connected to a motor for rotating it by means of a self-braking worm gear, the crown of a worm wheel of said gear being mounted on said slewing table.

11. A machine according to claim 10, wherein a shaft of the worm of said self-braking worm gear is provided with a spur gear which is in meshing engagement with another spur gear connected to said motor, the width of said spur gear corresponding to the amount of movement of said slewing table transversally relative to the axis of said pipe being bent.

12. A machine according to claim 1, wherein a motor of said means for axially moving the pipe and said motor performing the rotation of said slewing table comprise electric motors and are electrically coupled by means of an electriccircuit to a regulator of the ratio between the rotational speeds of these motors.

13. A machine according to claim 3, wherein said rods along which said holding ring moves are horizontally arranged.

Claims (13)

1. A machine for manufacturing a coiled pipe by bending the latter, comprising: a turntable rotating alternately clockwise and anticlockwise under the action of said pipe and adapted to effect additional movement at right angles to the longitudinal axis of said pipe; means for imparting said additional movement to sai turntable in two mutually opposite directions; at least two clamps having jaws being provided on said turntable and mounted so that a gap formed by a pair of jaws in one said clamp is in coaxial alignment with a similar gap of the other clamp while the machine is inoperative, said clamps being adapted to alternately engage said pipe after each rotation of said turntable; means in each of said clamps for raising and lowering movable parts thereof carrying the jaws; means for braking the rotational speed of said turntable, said last-mentioned means together with said turntable, said means for moving the turntable at right angles to the longitudinal axis of the pipe, and said clamps, forming a bending mechanism; heating means mounted on a stationary base between said clamps and adapted to heat said pipe in the zones of formation of the U-bends of the coil; a guiding sleeve mounted on said stationary base adjacent said heating means and datepd to facilitate passage there-through of said pipe toward said heating means while concurrently absorbing reaction forces produced by the bending of said pipe; means for moving said pipe along its longitudinal axis toward said bending mechanism and interacting with said means for braking the rotations of said turntable in response to the action of said means for axially moving said pipe, the latter means imparting motion to said turntable through the medium of said pipe due to the latter being fixed in one of said clamps; said pipe being bent in response to successively fixing said pipe in one of said clamps on said turntable, heating said pipe in the zone of formation of the future U-bend, moving said pipe along its longitudinal axis by said means for its axial movement and braking said turntable by said braking means as this table rotates under the action of said means for moving said pipe along its longitudinal axis, said turntable being rotated through the medium of this pipe and the braking of the table being necessary in order to build up the required axial compression of said pipe so as to prevent or reduce the thinning of its walls in the zone of formation of said U-bend; after completing the formation of this U-bend and releasing said pipe from said clamp, shifting said turntable at right angles to the longitudinal axis of said pipe and then advancing the latter toward said bending mechanism and fixing it in the other clamp, whereupon all said operations are resumed in the above-described succession.
2. A machine according to claim 1, wherein said means for axially moving said pipe comprise a slider having a clamp and mounted in straight guides made in said stationary base, said slider co-operating with two screws which are symmetrically arranged with respect to said clamp, said screws being connected to a motoR by means of a gear train.
3. A machine according to claim 1, wherein said slewing table is mounted in a holding ring having eyes through which parallel rods extend, said rods being fixed to said stationary base, and said holding ring being connected to an actuating cylinder adapted to move the ring along said rods.
4. A machine according to claim 3, wherein adjusting movable stops are provided adjacent the ends of said rods on said stationary base which are adapted to limit the movement of said holding ring along said rods.
5. A machine according to claim 4, wherein the ends of said rods are fixed to said stationary base by means of bushings received in holes appropriately made in said base, the end of each bushing which faces said holding ring being provided with a threaded portion co-operating with the adjusting movable stop which comprises a nut having teeth on the peripheral surface thereof, said teeth being in meshing engagement with a gear connected to a mechanical transmission.
6. A machine according to claim 5, wherein said bushings disposed adjacent the opposite ends of one and the same rod of said rods have oppositely directed threads, said adjusting movable stops co-operating with said bushings being in meshing engagement with gears mounted on one and the same shaft.
7. A machine according to claim 6, wherein said shafts carrying said gears are interconnected by means of a mechanical transmission to impart rotation to all said shafts synchronously.
8. A machine according to claim 6, wherein said slewing table is provided with straight guides in which there is mounted a slider carrying said pair of clamps and connected to means for moving said slider along said guides, said guides being arranged transversally relative to said gap between said jaws of said clamps.
9. A machine according to claim 8, wherein said movable parts carrying said jaws of each of said clamps in said bending mechanism comprise two double-arm levers joined by a common hinge which is loaded by springs which bear against said slider, said levers carrying a pair of said jaws at one identical ends thereof, while the other identical ends of these levers being interconnected by means of links having a common hinge which is connected to an actuating cylinder, the upward movement of said first-mentioned common hinge being limited.
10. A machine according to claim 1, wherein said slewing table is connected to a motor for rotating it by means of a self-braking worm gear, the crown of a worm wheel of said gear being mounted on said slewing table.
11. A machine according to claim 10, wherein a shaft of the worm of said self-braking worm gear is provided with a spur gear which is in meshing engagement with another spur gear connected to said motor, the width of said spur gear corresponding to the amount of movement of said slewing table transversally relative to the axis of said pipe being bent.
12. A machine according to claim 1, wherein a motor of said means for axially moving the pipe and said motor performing the rotation of said slewing table comprise electric motors and are electrically coupled by means of an electric circuit to a regulator of the ratio between the rotational speeds of these motors.
13. A machine according to claim 3, wherein said rods along which said holding ring moves are horizontally arranged.
US3845650A 1973-01-19 1973-01-19 Machine for manufacturing a coil of a pipe by bending it Expired - Lifetime US3845650A (en)

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Publication number Priority date Publication date Assignee Title
US4630459A (en) * 1985-06-03 1986-12-23 Rca Corporation Automatic coaxial cable bending apparatus
US5463890A (en) * 1992-05-29 1995-11-07 Kabushiki Kaisha Tachibana Seisakusho Automatic bending apparatus and marking device for band-shaped work
US6002118A (en) * 1997-09-19 1999-12-14 Mitsubishi Heavy Industries, Ltd. Automatic plate bending system using high frequency induction heating
US20040149000A1 (en) * 2003-02-04 2004-08-05 Stupecky Josef J. Swaging machine and method of use
US20050005664A1 (en) * 2003-07-09 2005-01-13 Wesley Scott System and method for bending strip material to create cutting dies
CN102825119A (en) * 2011-06-19 2012-12-19 江苏亚光金属制品有限公司 Single-end pipe bending machine of evaporator
CN104190769A (en) * 2014-09-01 2014-12-10 张家港市华机环保新能源科技有限公司 Device for bending copper pipe
US9833600B2 (en) 2005-12-16 2017-12-05 Interface Associates, Inc. Methods for manufacturing multi-layer balloons for medical applications

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Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4630459A (en) * 1985-06-03 1986-12-23 Rca Corporation Automatic coaxial cable bending apparatus
US5463890A (en) * 1992-05-29 1995-11-07 Kabushiki Kaisha Tachibana Seisakusho Automatic bending apparatus and marking device for band-shaped work
US6002118A (en) * 1997-09-19 1999-12-14 Mitsubishi Heavy Industries, Ltd. Automatic plate bending system using high frequency induction heating
US7010953B2 (en) * 2003-02-04 2006-03-14 Interface Associates, Inc. Swaging machine and method of use
US20040149000A1 (en) * 2003-02-04 2004-08-05 Stupecky Josef J. Swaging machine and method of use
US20060059970A1 (en) * 2003-07-09 2006-03-23 Wesley Scott System and method for bending strip material to create cutting dies
US20050005664A1 (en) * 2003-07-09 2005-01-13 Wesley Scott System and method for bending strip material to create cutting dies
US7082804B2 (en) 2003-07-09 2006-08-01 1500999 Ontario Inc. System and method for bending strip material to create cutting dies
US20060230805A1 (en) * 2003-07-09 2006-10-19 Scott Wesley E System and method for bending strip material to create cutting dies
US7254974B2 (en) 2003-07-09 2007-08-14 1500999 Ontario Inc. System and method for bending strip material to create cutting dies
US9833600B2 (en) 2005-12-16 2017-12-05 Interface Associates, Inc. Methods for manufacturing multi-layer balloons for medical applications
CN102825119A (en) * 2011-06-19 2012-12-19 江苏亚光金属制品有限公司 Single-end pipe bending machine of evaporator
CN104190769A (en) * 2014-09-01 2014-12-10 张家港市华机环保新能源科技有限公司 Device for bending copper pipe

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