US3274817A

US3274817A - Internal pipe bender

Info

Publication number: US3274817A
Application number: US359902A
Authority: US
Inventors: James H Anderson
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-04-15
Filing date: 1964-04-15
Publication date: 1966-09-27
Anticipated expiration: 1983-09-27

Description

Sept 27, 6 J. H. ANDERSON INTERNAL PIPE BENDER 5 Sheets-Sheet 1 Filed April 15, 1964 E RN N rR vW W M W 1 n w m@ W 7 p 7, 1966 J. H. ANDERSON 3,274,?

INTERNAL PIPE BENDER Filed April 15, 19 5 Sheets-Sheet FJ a I V Y /1 260 282 288 284 -23s i 7: {O u mun 3: 294 L 1, 296 290 I s all N A 254 J M Q r/ A INVENTOR.

JAMES H. ANDERSON Z, g flM MJM A 1"! (JAN/53117.

Sept. 27, 1966 ANDERSON 3,274,317

INTERNAL PIPE BENDER Filed April 15, 19 4 5 Sheets-Sheet. 5

INVENTOR. JAMES H. ANDERSON BY 7 M mjwgczsw United States Patent 3,274,817 INTERNAL PEPE FENDER James H. Anderson, 1615 Hilloclr Lane, York, Pa. Filed Apr. 15, 1964, Ser. No. 352,902 19 tClaims. (Cl. 72--298) This invention relates generally to the art of pipe bending and more specifically to a new and improved method and apparatus for bending pipes, tubes and like structure.

Prior art structures for bending pipes and the like have generally been designed to operate on the exterior of the pipe to deform the walls by the application of external pressure. This kind of structure, especially the type designed to bend pipes of large diameter, is expensive, bulky and usually limited in use to situations where the exterior of the pipe being bent is readily accessible to the machinery.

A further defect in the prior art pipe bending devices is the intentional or inadvertent wrinkling of the pipe in the area of the bend due to in many instances the lack of interior support for the walls of the pipe when external pressure is applied thereto. Apparatus in the form of flexible mandrels, such as shown in Ballard, 2,984,284, and Avera et al., 3,109,477, do provide an interior support for the pipe during the bending operation as performed by an external pipe bending device. Although these devices are very successful in their objectives, they do entail additional operation and equipment expense in the bending operation.

It is, therefore, an object of the present invention to provide a method and apparatus for bending pipe which avoids the above-stated defects of the prior art by providing an apparatus which effects a bending of pipes and tubular objects entirely from the interior surfaces thereof.

It is another object of this invention to provide a pipe bending device having a mandrel-type member engageable with the interior of a pipe to internally support the pipe during bending for achieving a smooth wrinkle-free bend in the pipe.

It is a further object of this invention to provide a pipe bending device having an internal pipe engaging member which may be located in remote, relatively inaccessible portions of the pipe to effect a bending thereof.

It is still another object of this invention to provide an internal pipe bending device which bends pipe where the exterior portions thereof are not accessible for the conventional bending operation.

These and other objects will become more apparent to those skilled in the art by reference to the following detailed description when viewed in light of the accompanying drawings in which like numerals indicate like parts throughout the figures thereof and wherein:

FIG. 1 is an elevational view in section of a pipe bending apparatus embodying the features of the present invention;

FIG. 2 is a view similar to FIG. 1 showing the apparatus thereof at the termination of its bending operation;

FIG. 3 is a vertical sectional View of the apparatus of FIG. 1, the view being taken along the lines 3-3 thereof;

FIG. 4 is an elevational view in seciton of a portion of a modified apparatus embodying the features of the invention;

FIG. 5 is an elevational view in section of another pipe bending apparatus embodying features in accordance with the invention;

FIG. 6 is an elevational view in section of still another pipe bending apparatus embodying features of the present invention; and

FIG. 7 is an elevational View in section of a portion of ice yet another pipe bending apparatus in accordance with the present invention.

This invention consists of two gripping members for engaging the inner surface of a pipe at axially spaced points and means for displacing the gripping members angularly with respect to one another. This provides a stretching or compressing of a circumferential portion of the wall of the pipe to induce a bend therein. In certain embodiments of the invention means are provided for alternately lengthening and shortening the distance between the gripping members while they are first in a gripping and then in a non-gripping state to provide for a crawling travel of the gripping members and means through the interior of the pipe.

Referring to FIG. 1 of the drawings there is shown an internal pipe bending apparatus 16, positioned in the interior of a pipe 18. The apparatus consists of a pair of

circular gripping members

20 and 22, that are disposed in spaced relationship to one another and connected together by a tension link 24 and an expansible and contractible working link 26.

Each of the gripping

members

20 and 22 is substantially identical in mirror asymmetry so that the following description will be directed to one of said members. The gripping member 20 is formed with a cylindrical body 28 having inner and outer disc shaped

walls

30 and 32 respectively, connected together by a cylindrical web 34. The web is of a smaller diameter than that of the

Walls

30 and 32 to form an annular recess or chamber 36 around the periphery of the body 28. An expansible sealing ring 38, preferably formed of elastomeric material, is slidably disposed between the outer ends of the

walls

30 and 32 to seal the open end of the chamber 36. An annular split ring 40, fabricated of a relatively hard material such as steel or the like, is positioned around the sealing ring 38 and provides an expandable backing member therefor. The ring 40 is formed with slots 42 (FIG. 3), which furnishes the expansible capability therefore, while an annular gripping ring 44, is disposed in a recess around the split ring 40. The ring 44 is fabricated from or faced with a material harder than the material of the pipes to be bent, and, in addition, said ring is provided with slots 46 (FIG. 3) to permit it to expand and contract. The inner wall 30 of the gripping member 20 is formed with a port 48 that receives a flexible conduit 50 to provide hydraulic communication between the chambers 36 in the gripping members 20 and i 22. The wall 32 of the gripping member 22 is provided with a port 52 communicating with the chamber 36 and which is connected by a flexible conduit 54 to a source of hydraulic pressure, not shown, for alternately supplying and bleeding hydraulic fluid to and from the chambers.

In the operation of the gripping

members

20 and 22, hydraulic fluid under suitable pressure is supplied to the chambers 36 through the supply conduit 54 and conduit Stl, thereby expanding the sealing rings 38 and split rings 40 to force the rings 44 into gripping contact with the interior of the pipe 18. The gripping surface of the rings 44 is slightly roughened by pit marks or grooves to provide the greatest possible frictional holding force for the gripping members.

The tension link 24 is pivotally mounted between lugs 56 provided on the inner surface of the walls 30 to conmeet the gripping

members

20 and 22 together at a point spaced from the common symrnetrioal axis thereof. The link 24 consists of a pair of oppositely threaded

rods

55 and 57 having one end CUIlIIEC'lICld to the lugs 56 and the other end connected together by a collar 58 having oppositely threaded halves therein to mate with the threads on the rods. Rotation of the collar 58 with respect to the

rods

55 and 57 provides a lengthening or shortening adjustment of the rods with respect to the collar depending on the direction of rotation.

The working link 26 of the apparatus is pivotally connected to lugs 60 formed on the inner surfaces of the walls 30 at a point spaced from the common axis of symmetry of the gripping members and diametrically opposite the position of the tension link 24. The working link consists of a cylinder 62 that has a closed end connected to the lug 60 of the gripping member 22, while Ia piston and piston rod 64 are slidably disposed therein, with the rod being connected to the lug 60 of the gripping member 20. The area of the cylinder 62 between the closed end and the piston 64 defines a pressure chamber 66 While the open end of the cylinder has secured thereto an inwardly projecting flange 68 to limit the movement of the piston 64 in one direction of movement in the cylinder. A piston sealing ring 70 is mounted on the head of the piston. A port 72 formed in the closed end of the cylinder 62 receives a conduit 76 which is connected to a chamber 74 formed in the central portion of the gripping member 22. The chamber 74 is formed with a port 80 that has a conduit 78 disposed therein for communicating with a source of pressure supply (not shown).

Referring to FIG. 2 the apparatus is shown in an exaggerated condition for bending the pipe 18. The apparatus is positioned in the pipe 18 With the gripping

members

20 and 22 engaging the inner-periphery of the pipe at spaced points. The piston and rod 64 are actuated upon the delivery of fluid to the chamber 66 by way of conduit 78, chamber 74 and conduit 76, to force the piston towards the flange 68. The movement of the piston and rod 64 angularly displaces the gripping

members

20 and 22 with respect to one another by forcing the upper portions of the members apart while the tension link 24 retains the lower portions of the gripping members in their initial spaced relation. The gripping members 20 land 22,

being so disposed and in frictional engagement with the interior surface of the pipe, will stretch the upper wall' portions of the pipe, producing a bend in the pipe (FIG. 2). Deformation of the pipe, because of the normal stress transmission characteristics of homogenous material, as well 'as the tension and bending stresses imposed on adjacent portions of the structure, will be distributed in decreasing quantities from the point sources of stress to produce a relatively smooth and even bend in the pipe.

In the event that the strength of the pipe material or the thickness of the walls thereof exceeds the holding capability of the gripping members shown in FIGS. 1 through 3, or the pressure required to hold or grip exceeds the circumferential strength of the pipe at single gripping points, additional gripping units may be employed as shown in FIG. 4. The gripping means 122 in this embodiment is formed with a pair of

adjacent chambers

136 and 137 and which are connected to independent sources of pressure (not shown) by means of

flexible conduits

153 and 154. The

chambers

136 and 137 are provided with sealing rings 138 and

split rings

140 and 141, as in the embodiments of FIGS. 1 through 3. Gripping

rings

144 and 145, respectively are positioned in recesses in the split rings. Although the operation of the device shown in FIG. 4 is the same as the previous embodiment, the area of contact and therefore the frictional force or resistance to movement of the gripping member is increased through the provision of the additional gripping ring 145. The use of additional gripping rings offers a further advantage in that the gripping force may be graduated with respect to the area of stress generated by the bending of the pipe. In the embodiment of FIG. 4, this advantage is brought about by placing the larger contact area of the gripping ring 144 closer to the area of bending stress in the pipe than the smaller contact area of the gripping ring 145 so that the circumferential stress generated in the pipe by the expansion of the gripping ring is lower proximate the point of bending stress. The

circumferential stress from the gripping rings may also he graduated by supplying lower hydraulic pressure to the chamber 136 than that supplied to the chamber 137.

Although the number of chambers in each gripping member can obviously be varied, the length of the structure would be limited dependent upon its passage through the bends of the pipe because of the rigid connection between the adjacent chambers. It is therefore readily conceivable that the chambers may be formed as individual units connected to one another by suitable fasteners, such as bolts or the like. The fasteners may be loosened by extension wrenches or the like during the passage of the device through the pipe to allow angular displacement between the adjacent units and tightened for rigid connection between the units during the gripping and bending portion of their cycle.

In FIG. 5 there is shown a further variation of the bending apparatus wherein corresponding parts have been identified by the same reference numerals, only using the next higher series. In this embodiment the primary distinction is in the working link 226 which consists of a screw jack having a pair of oppositely threaded

rods

282 and 284 and having an end thereof pivotally connected to the lugs 260 on the gripping

members

220 and 222. The free ends of the rods are connected together by a sleeve 286 which is threaded over said ends in such a manner that rotation of the sleeve in opposed directions will lengthen or shorten the working link 226. The sleeve 286 is formed with teeth 288 that cooperate with a link drive chain 290 disposed around a portion of the periphery thereof. A motor 292, connected to a suitable source of power (not shown) is mounted in a bore 294 centrally formed in the gripping member 22. The motor 292 has, extending therefrom, a spline power shaft 296 which has a sprocket 298 mounted thereon for rotation therewith. The teeth of the sprocket 298 engage the links of the drive chain 290 to supply driving power to the sleeve 286.

In operation the apparatus is positioned in the pipe with the gripping rings 244 engaging the interior walls thereof and, power is supplied to the motor 292 to drive the sprocket 298 and chain 290 causing rotation of the sleeve 286 and extension or retraction of the working link 226 and a resulting bending of the pipe. Since the link is not concentric to the centerline of the pipe, the extension or retraction of the link will produce a greater tension in the upper wall than in the lower wall of the pipe thereby exceeding the yield point of the upper pipe wall before exceeding that of the lower pipe wall when the force is great enough. In this manner, the apparatus may be used to accomplish bending without the use of a tension link as in the preceding figures. Obviously, several chain drives may be utilized to increase the operating force of the apparatus or the number of screw jacks or working links 226 could be increased and powered by suitable drive arrangement to increase the amount of force available for the bending operation.

The use of a single, eccentric link to connect the two gripping members of the device also provides a particular advantage since the bending apparatus can then be made to travel, under its own power, to the point in the pipe where same is to be bent. This can be achieved by providing separate pressure sources for the

gripping members

220 and 222 respectively, and with the apparatus of FIG. 5, first applying pressure only to the gripping unit 222 then, operating motor 292 to extend the working link 226 thereby moving the gripping member 220 along the pipe to the limit of the extension of the link 226, releasing the pressure in the gripping member 222 while applying pressure to the gripping member 220, then retracting the link 226 by counter-rotation of motor 292 to pull the gripping member 222 towards the gripping member 220 and repeating this operation to providefor a crawling or walking type of movement of the apparatus along the pipe. This procedure could obviously be atomatized through the use of proper electrical and hydraulic controls and limit switches so that the apparatus may be automatically moved to remote locations in a pipe string to perform a bending operatlon at that point even when the exterior of the structure is inaccessible. This crawling capability can also be utilized to provide a bend at one point in a pipe, then automatically move to another point to perform a bending operation and so on to provide a bend in a pipe having a large continuous radius.

In FIG. 6 there is shown a hydraulic pipe bending apparatus having the crawling capability which consists of a piston cylinder combination in the working link 326 as well as the tension link 324. The working link 326 is essentially the same as that described for the embodiment of FIG. 1 with the exception that an end plate 368 encloses the open end of the cylinder to form a pressure chamber 367 so that the piston 364 operates between a pair of

pressure chambers

366 and 367. Each of the chambers has connected thereto a pressure conduit 369 and 376, respectively, which in turn are connected to a suitable source of pressure, not shown. A seal 381 is provided in the plate 368 for engagement with the piston rod to prevent the escape of any fluid from the chamber 367.

The tension link 324 includes a piston cylinder combination which is essentially identical to that of the working link 326. A cylinder 317, having a closed end connected to the lug 356 on gripping member 320 by a rod 319, also is closed at the other end by a plate 321 to form chambers 323 and 325 on opposite sides of a piston 327. A seal 329 is provided in the plate 321 for the identical purposes as that described for seal 331 in the working link 326. Chambers 323 and 325 are connected to suitable sources of pressure by conduits 331 and 333.

In operation, the apparatus is positioned within a pipe and fluid under pressure is supplied to chamber 366 through conduit 376 to extend the working link 326 and thereby bend the pipe. During this operation, the piston 327 may be disposed in one of several positions depending upon the type of bend to be formed in the pipe. The piston may be locked in place or it may be retracted by supplying pressure through flexible conduit 333 to provide compression in the lower portion of the wall or it may be extended by supplying pressure through conduit 331 to extend the tension link 324 simultaneously with the bending operation to provide a wider radius bend in the pipe.

The crawling capability of the device is achieved by hooking the conduits 369 and 333 as well as the

conduits

331 and 336 to the same pressure source or to pressure sources which act in unison and then alternating the sup ply of pressure to first one side of the pistons and then to the other. With the above hydraulic arrangement and with alternate actuation of gripping members, as described for the embodiment of FIG. 5, the apparatus will crawl through the pipe to a desired location. Obviously, this type of power device may be adapted to automatic operation as easily as the mechanical apparatus described in FIG. 5.

With reference to FIG. 7 of the drawings, a further variation of the gripping member of the invention is illustrated wherein parts corresponding to previous embodiments have been identified by the same reference numeral only using the next higher series. In this figure, three identical gripping units 315 are mounted as a unit on the end of the gripping unit 320, which gripping unit may form part of any of the previously described pipe bending structures. As was pointed out in connection with the structures shown in FIG. 4, an increase in the number of gripping units increases the holding force of the gripping members without too great an increase in the cylindrical stress on the pipe where such increases are necessary. In this embodiment, the units 315 are connected to the end unit 322 by bolts 335 fastened thereto by nuts 337. There is provided some degree of flexiblity in the mounting of the units by the interposition of

conical spring washers

343 and 345 under the heads of the bolts 335. The units are normally kept in abutting relationship to one another but may extend or deflect angul arly to negotiate curves in the pipe when the apparatus is being moved therethrough.

The above-described embodiments are, of course, illustrated merely to show those skilled in the art, specific ways in which the present invention may be carried out to effectively and efficiently bend pipes or other tubular members and obtain relatively free and smooth areas of bend in the pipes. It should also be obvious that the features of the particular structures as set forth may be readily interchanged Within the basic concepts of the invention. It should, therefore, be understood that, within the scope of the appended claims, the invention may be practiced otherwise than is specifically set forth. What is claimed as new and is desired to be protected by Letters Patent of the United States is:

1. An apparatus for bending a tubular structure comprising gripping members positioned Wi-thin a tubular structure in axially spaced relation to one another, means to actuate said gripping members to engage said tubular structure, a second means interposed between and connecting said gripping members, said second means being operative to effect angular displacement between said gripping members or stretching a portion of the wall of said tubular structure to effect a bend therein.

2. An apparatus in accordance With claim 1 wherein said second means also eifects axial displacement between said gripping members and said actuating means is further adapted to actuate said gripping members independently of one another, said apparatus being movable through said tubular structure by alternate actuation of each of said gripping members and corresponding alternate operation of said second means to provide extending and retracting axial displacement between said gripping members.

3. An apparatus for bending a tubular structure comprising:

a pair of gripping members positioned in a tubular structure in axially spaced relation to one another, means to actuate said gripping members to conform to and grip said structure;

a second means interposed between and connecting said gripping members, and a link means interposed between and connecting said gripping members and being spaced from said second means, said second means being operative to effect at least angular displacement between said gripping members for stretching a portion of the wall of said tubular structure to effect a bend therein.

4. An apparatus in accordance with claim 1 wherein said second means comprises:

at least one link pivotally connecting said gripping members in spaced relationship to the axial centerline thereof;

and at least one extending means associated with said one link to effect axial extension of that link, means to actuate said extending means to impose an asymmetrical -force between said gripping members for pivotal displacement therebetween when both of said gripping members are in gripping engagement with the interior of said structure.

5. An apparatus in accordance with claim 4 wherein siad extending means comprises a hydraulic piston-cylinder combination interposed between and connecting the ends of said link to provide extension thereof, and conduit means including a valve for selectively connecting at least one side of said piston to a source of hydraulic pressure to selectively actuate said piston to at least extend said link.

6. An apparatus in accordance with claim 4 wherein said extending means comprises a rotary screw jack interposed between the ends of said link and means to selectively rotate said screw jack to effect at least axial extension of said link.

7. An apparatus in accordance with claim wherein means are provided to selectively connect hydraulic pressure to both sides of said piston, whereby the supply of hydraulic pressure to alternate sides of said piston effects corresponding extension and retraction of said link.

8. An apparatus in accordance with claim 4 wherein a second link pivotally connects said gripping members at a point transversely spaced from said one link.

9. An apparatus in accordance with claim 8 wherein extending means are associated with said one link and said second link to effect axial extension and retraction of said links, and means to actuate said extending means, actuation of one of said extending means alone effecting pivotal displacement between said gripping members and similar actuation of both of said extending means simultaneously effecting axial displacement between said gripping members.

10. An apparatus in accordance with claim 1 wherein said gripping members comprise at least one circular plug defining an annular chamber around and open to the periphery thereof, annular resilient sealing means disposed to enclose and seal the outer periphery of said chamber, said sealing means being radially slidable in said chamber, an annular expansible gripping ring disposed around said sealing means, conduit means including valves to selectively connect said chamber to a source of hydraulic pressure, the supply of hydraulic pressure to said chamber expanding said seal and gripping ring into gripping contact with the inner periphery of said tubular structure, and means to selectively exhaust hydraulic pressure from said chamber, said gripping ring being withdrawn from gripping contact with the inner periphery of said tubular structure when pressure is exhausted from said chamber.

11. An apparatus in accordance with claim 10 wherein the said gripping members comprise a plurality of said plugs in axially abutting relationship to one another, and means to connect said plugs together.

12. An apparatus in accordance with claim 11 wherein said means to connect said plugs together includes resilient means to bias said plugs in abutting relationship yet provide a resilient angular displacement capability between said plugs.

13. An apparatus in accordance with claim 11 wherein the axial Width of said gripping ring for each of said plugs is successively larger in stepped increments away from the plugs most proximate said second means.

14. An apparatus for bending a tubular structure comprising a pair of axially spaced gripping members positioned in and comformable to the inner periphery of a tubular structure along transverse planes thereto, said gripping members comprising:

(a) At least one circular plug defining an annular chamber around and open to the periphery thereof;

(b) annular resilient sealing means disposed to enclose and seal the outer periphery of said chamber, said sealing means being radially slidable in said chamber;

(c) an annular expansible gripping ring around said sealing means;

(d) conduit means including valves to selectively connect said chamber to a source of hydraulic pressure; the supply of hydraulic pressure to said chamber expanding said seal and said gripping ring into gripping contact with the inner periphery of said tubular structure;

disposed 8 (e) and means to selectively exhaust hydraulic pressure from said chamber;

said gripping ring being withdrawn from gripping contact with the inner periphery of said tubular structure when pressure is exhausted from said chamber; and a second means disposed between and connecting said gripping members and operative to provide at least angular displacement therebetween comprising:

(a) at least one link pivotally connecting said gripping members and disposed in spaced relationship to the axial centerline thereof;

(b) and at least one extending means associated with said link to effect axial extension of that link, means to actuate said extendind means to apply an asymmetrical axially extending force to said gripping members to thereby produce pivotal displacement therebetween when both of said gripping members are in gripping engagement with the interior of said structure for stretching a portion of the wall of said tubular structure to effect a bend therein.

15. An apparatus in accordance with claim 14 wherein said extending means comprises a hydraulic piston-cylinder combination interposed between the ends of said link to provide extension thereof, conduit means including a valve to connect at least one side of piston to a source of hydraulic pressure to selectively actuate said piston.

16. An apparatus in accordance with claim 14 wherein said extending means comprises a rotary screw jack interposed between the ends of said link and means to selectively rotate said screw jack to effect axial extension and retraction of said link.

17. An apparatus in accordance with claim 15 wherein means are provided to selectively connect hydraulic pressure to both sides of said piston, the supply of hydraulic pressure to alternate sides of said piston effecting alternate extension and retraction of said link.

18. An apparatus in accordance with claim 14 wherein a second link pivotally connects said gripping members at points transversely spaced from said one link.

19. An apparatus in accordance with claim 18 wherein extending means are associated with said one link and said second link to effect axial extension and retraction of both of said links, and means to selectively actuate said extending means, the actuation of one of said extending means effecting pivotal displacement between said gripping members and similar actuation of both of said extending means, simultaneously, effecting axial displacement between said gripping members.

References Cited by the Examiner UNITED STATES PATENTS 520,870 6/1894 Winfield et a1 72-298 1,804,384 5/1931 Miller 72-298 2,371,393 3/1945 Horrigan 72-392 3,109,477 11/1963 Avera et a1 72-466 CHARLES W. LANHAM, Primary Examiner. L. A. LARSON, Assistant Examiner.

Claims

1. AN APPARATUS FOR BENDING A TUBULAR STRUCTURE COMPRISING GRIPPING MEMBERS POSITIONED WITHIN A TUBULAR STRUCTURE IN AXIALLY SPACED RELATION TO ONE ANOTHER, MEANS TO ACTUATE SAID GRIPPING MEMBERS TO ENGAGE SAID TUBULAR STRUCTURE, A SECOND MEANS INTERPOSED BETWEEN AND CONNECTING SAID GRIPPING MEMBERS, SAID SECOND MEANS BEING OPERATIVE TO EFFECT ANGULAR DISPLACEMENT BETWEEN SAID GRIPPING MEMBERS OR STRETCHING A PORTION OF THE WALL OF SAID TUBULAR STRUCTURE TO EFFECT A BEND THEREIN.