Pipe bending system

Claim 2

An improved pipe bending system, comprising: a main frame having a pin-up end and a stiffback end; a longitudinally convex and transversely concave elongated bending die for pipe bend confirmation thereto secured to the main frame intermediate its length, the face of the die being positioned downwardly so the pipe may be bent thereagainst; a transversely concave elongated stiffback for bending the pipe against the die, the stiffback being movably secured by expansible and contractible means to the main frame and extending at least from a point adjacent the end of the die nearest the pin-up end of the main frame to a point adjacent the stiffback end of the main frame; a movable expansible and contractible, internal pipe-supporting mandrel for supporting preselected portions of the internal wall of the pipe during bending; means for positioning the mandrel within the pipe to be bent at preselected positions with respect to the die; a transversely concave pin-up shoe for supporting the pipe movably secured to the main frame adjacent its pin-up end; a pin-up clamp secured to the pin-up shoe for supporting a portion of the exterior wall of the pipe during bending; and a stiffback clamp secured to the stiffback a preselected distance from the end of the die nearest the stiffback end of the main frame for supporting a portion of the exterior wall of the pipe during bending.

Claim 3

An improved pipe bending system according to claim 1, including an expansible and contractible internal pin-up support associated with the pin-up end of the main frame for providing support for a preselected portion of the internal wall of the pipe during bending.

Claim 4

An improved pipe bending system according to claim 1, including an expansible and contractible internal stiffback support associated with the stiffback end of the main frame for providing support for a preselected portion of the internal wall of the pipe during bending.

Claim 5

An improved pipe bending system according to claim 2, where the internal stiffback support comprises: an upper assembly presenting a transversely convex pipe engaging surface, at least a portion of which is a resiliently compressible material; a lower assembly presenting a transversely convex pipe engaging surface; and means for selectively moving the upper and lower assemblies away from each other and into engagement with the interior of the pipe.

Claim 6

An improved pipe bending system according to claim 1, wherein the means for movably securing the stiffback to the main frame includes: at least two inboard cylinder and piston assemblies connected to the stiffback and the main frame intermediate its length for providing a pivot for the stiffback during the bending process; aNd at least two outboard cylinder and piston assemblies connected to the stiffback and the main frame adjacent the stiffback end thereof for providing the bending forces required by the stiffback to bend the pipe against the die.

Claim 7

An improved pipe bending system according to claim 5, wherein the outboard and inboard cylinder and piston assemblies are hydraulically operating and including: means on the main frame for supplying hydraulic fluid under pressure to the assemblies; and a sequence valve connected to the means for supplying hydraulic fluid for regulating the supply and the pressure of the hydraulic fluid so that the pressure of the fluid supplied to the inboard assemblies is of a preselected magnitude before the pressure of the fluid supplied to the outboard assemblies is increased sufficiently for the stiffback to bend the pipe against the die.

Claim 8

An improved pipe bending system according to claim 1, wherein the stiffback clamp includes: a first arcuate supporting plate hinged to the top of the one side of the stiffback; a second arcuate supporting plate hinged to the top of the other side of the stiffback; a third arcuate plate connected to the first plate and slidable around the outer surface of the second plate; a locking toggle mechanism connected between the second plate and the third plate; and a cylinder and piston assembly connected between the locking toggle mechanism and the second plate for operating the locking toggle mechanism.

Claim 9

An improved pipe bending system according to claim 1, wherein the internal support mandrel includes: an elongated, longitudinally flexible upper assembly for providing support to the interior wall of the section of the pipe in contact with the bending die, the upper assembly including at least one hydraulic packer mounted in a resiliently compressible pipe engaging material; an elongated, longitudinal flexible lower assembly for providing support to the interior wall of the section of the pipe in contact with the stiffback in the vicinity of the die; and means secured to and between the upper and lower assemblies for selectively moving the assemblies away from and toward each other and into and out of engagement with the interior wall of the pipe.

Claim 10

An improved pipe bending system according to claim 8 wherein the upper assembly includes: a plurality of elongated hydraulically inflatable bags hydraulically connected in sets; and a resiliently compressible material enveloping the bags and presenting a transversely convex pipe engaging surface.

Claim 11

An improved pipe bending system according to claim 9 wherein the upper and lower assemblies and the means for moving the upper and lower assemblies apart from each other include: downwardly facing cam surfaces and shoulders mounted on the upper assembly; upwardly facing cam surfaces and shoulders mounted on the lower assembly; at least one transversely movable toggle bar having bosses protruding therefrom for contacting the cam surfaces and shoulders and mounted between the upper and lower assemblies; and at least one cylinder and piston assembly mounted between the upper and lower assemblies for transversely moving the toggle bar; the shoulders on the upper and lower assemblies and the toggle bar forming a sturdy mechanical support between the upper and lower assemblies when the mandrel is in its expanded condition.

Claim 12

An improved pipe bending system according to claim 1, including: an expansible and contractible internal stiffback support associated with the mandrel so that when the mandrel is properly positioned with respect to the bending die, the stiffback support is positioned in a selected relationship with respect to the stiffback clamp; and an expansible and contractible internal pin-up support associated with the mandrel so that when the mandrel is properly positioned with respect to the bending die, the pin-up support is positioned in a selected relationship witH respect to the pin-up clamp.

Claim 13

An improved pipe bending machine, including: a main frame having a stiffback end and a pin-up end; a pipe bending die secured to the main frame intermediate its length; a stiffback movably connected to the main frame through expansible and contractibel cylinder and piston assemblies for bending pipe against the die; a pin-up shoe movably connected to the main frame adjacent its pin-up end; a pin-up clamp secured to the pin-up shoe; and a stiffback clamp secured to the stiffback.

Claim 14

An improved pipe bending machine, including: a main frame having a stiffback end and a pin-up end; a pipe bending die secured to the main frame intermediate its length; a stiffback movably connected to the main frame through expansible and contractibel cylinder and piston assemblies for bending pipe against the die; a pin-up shoe movably connected to the main frame adjacent its pin-up end; a pin-up clamp secured to the pin-up shoe; and a stiffback clamp secured to the stiffback.

Claim 15

An improved pipe bending machine according to claim 12, including: an internal pin-up support flexibly associated with the pipe bending machine adjacent to the pin-up clamp; and an internal stiffback support flexibly associated with the pipe bending machine adjacent to the stiffback clamp.

Claim 16

An improved pipe bending machine according to claim 13, wherein each of the pin-up support and the stiffback support comprises: an upper assembly presenting a transversely convex pipe engaging surface, at least a portion of which is a resliently compressible material; a lower assembly presenting a transversely convex pipe engaging surface; and means for selectively moving the upper and lower assemblies away from each other and into engagement with the interior of the pipe.

Claim 17

An improved pipe bending machine according to claim 12, wherein the expansible and contractible cylinder and piston assemblies movably connecting the stiffback to the main frame include: at least one inboard hydraulic cylinder and piston assembly connected to each side of the stiffback and the main frame intermediate its length, the inboard cylinder and piston assemblies being positioned in a selected relationship to the bending die to provide a pivot for the stiffback during the bending process; and at least one outboard hydraulic cylinder and piston assembly connected to each side of the stiffback and to the main frame adjacent its stiffback end, the outboard cylinder and piston assemblies providing the upward forces on the stiffback for bending the pipe held in the stiffback against the die; and means for supplying hydraulic fluid under pressure to the inboard and outboard assemblies, including a sequence valve for allowing the pressure of the hydraulic fluid supplied to the inboard assemblies to exceed a preselected magnitude prior to the pressure of the hydraulic fluid supplied to the outboard assemblies increasing to a magnitude sufficient for the stiffback to bend the pipe against the die.

Claim 18

An improved pipe bending machine according to claim 12, wherein the stiffback clamp includes: means for providing support for a selected portion of the exterior wall of a pipe held in the stiffback pivotally secured to the stiffback adjacent the end of the die nearest to the stiffback end of the main frame and movable between open and closed positions; and means secured to the support means for selectively moving the support means between the open and closed positions; the support means and the stiffback conjunctively providing nearly full circular support for the pipe when the support means is moved to the closed position.

Claim 19

An improved pipe bending machine, including: an elongated main frame for receiving the pipe to be bent, the main frame having a pin-up end and a stiffback end; a downwardly facing die presenting a longitudinally convex and transversely concave surface against which the pipe is to be bent, the die being secured to the main frame intermediate its length and adjacent its highest elevation; an upwardly facing stiffback presenting an elongated, transfersely concave surface for cradling the pipe to be bent and for bending the pipe against the die, the stiffback being movably connected to the main frame; a pin-up shoe movably connected to the main frame adjacent its pin-up end for providing the fulcrum for the end of the pipe which is to remain stationary during the Bending process, the pin-up shoe providing a transversely concave surface in which the pipe is cradled; a pin-up clamp attached to the pin-up shoe; and a stiffback clamp attached to the stiffback intermediate the stiffback end of the main frame and the end of the bending die nearest the stiffback end of the main frame, the stiffback clamp being expansible to allow the pipe to be moved longitudinally through the stiffback and being contractible to provide with the stiffback nearly full circular support for a selected portion of the exterior wall of the pipe during the bending process.

Claim 20

An improved pipe bending machine, including: an elongated main frame for receiving the pipe to be bent, the main frame having a pin-up end and a stiffback end; a downwardly facing die presenting a longitudinally convex and transversely concave surface against which the pipe is to be bent, the die being secured to the main frame intermediate its length and adjacent its highest elevation; an upwardly facing stiffback presenting an elongated, transfersely concave surface for cradling the pipe to be bent and for bending the pipe against the die, the stiffback being movably connected to the main frame; a pin-up shoe movably connected to the main frame adjacent its pin-up end for providing the fulcrum for the end of the pipe which is to remain stationary during the Bending process, the pin-up shoe providing a transversely concave surface in which the pipe is cradled; a pin-up clamp attached to the pin-up shoe; and a stiffback clamp attached to the stiffback intermediate the stiffback end of the main frame and the end of the bending die nearest the stiffback end of the main frame, the stiffback clamp being expansible to allow the pipe to be moved longitudinally through the stiffback and being contractible to provide with the stiffback nearly full circular support for a selected portion of the exterior wall of the pipe during the bending process.

Claim 21

An improved pipe bending machine according to claim 17, including an expansible and contractible pin-up support flexibly depending from a rotatable davit attached to the main frame adjacent its pin-up end for providing internal support to the rearward end of the pipe during the bending process whenever the rearward end of the pipe is adjacent the pin-up clamp.

Claim 22

An improved pipe bending machine according to claim 17, including an expansible and contractible stiffback support flexibly depending from a rotatable davit attached to the means movably connecting the stiffback to the main frame for providing internal support to the forward end of the pipe during the bending process whenever the forward end of the pipe is adjacent the stiffback clamp.

Claim 23

An improved method of bending pipe, including the steps of: cradling the portion of the pipe to be bent in a stiffback and beneath a bending die; cradling the rearward portion of the pipe extending from the stiffback in a pin-up shoe; positioning an internal support mandrel inside the pipe in a selected space relationship with the bending die; inflating a plurality of individual, elongated, inflatable bags included in the mandrel to varying magnitudes of pressure with the greatest pressure in the bags adjacent the apex of the portion of the pipe to be bent against the die; performing in any sequence the steps of: closing a stiffback clamp secured to the stiffback around the pipe; expanding the mandrel against the interior wall of the pipe thereby shaping the pipe so it is elongated slightly in the direction of the die; applying upward forces to the stiffback adjacent the die and adjacent the forward end of the stiffback to raise the stiffback and the pipe cradled therein sufficiently for the pipe to lightly contact the die; applying upward forces to the pin-up shoe to raise the pin-up shoe into firm supporting contact with the rearward portion of the pipe; closing a pin-up clamp secured to the pin-up shoe around the pipe; increasing the upward forces being applied to the stiffback adjacent the die to a selected magnitude; and increasing the upward forces being applied to the stiffback adjacent its forward end to a selected magnitude whereby the forward end of the stiffback pivots upwardly, thereby bending the pipe against the die with the rearward portion of the pipe held stationary by the pin-up shoe.

Claim 24

An improved method of bending pipe, including the steps of: cradling the portion of the pipe to be bent in a stiffback and beneath a bending die; cradling the rearward portion of the pipe extending from the stiffback in a pin-up shoe; positioning an internal support mandrel inside the pipe in a selected space relationship with the bending die; inflating a plurality of individual, elongated, inflatable bags included in the mandrel to varying magnitudes of pressure with the greatest pressure in the bags adjacent the apex of the portion of the pipe to be bent against the die; performing in any sequence the steps of: closing a stiffback clamp secured to the stiffback around the pipe; expanding the mandrel against the interior wall of the pipe thereby shaping the pipe so it is elongated slightly in the direction of the die; applying upward forces to the stiffback adjacent the die and adjacent the forward end of the stiffback to raise the stiffback and the pipe cradled therein sufficiently for the pipe to lightly contact the die; applying upward forces to the pin-up shoe to raise the pin-up shoe into firm supporting contact with the rearward portion of the pipe; closing a pin-up clamp secured to the pin-up shoe around the pipe; increasing the upward forces being applied to the stiffback adjacent the die to a selected magnitude; and increasing the upward forces being applied to the stiffback adjacent its forward end to a selected magnitude whereby the forward end of the stiffback pivots upwardly, thereby bending the pipe against the die with the rearward portion of the pipe held stationary by the pin-up shoe.

Claim 25

An improved method of bending pipe according to claim 20, including at some point prior to the step of increasing the upward forces on the forward end of the stiffback sufficient to pivot the stiffback, the steps of: if the rearward end of the pipe is adjacent the pin-up clamp, expanding an internal pin-up support positioned in a selected space relationship with the pin-up clamp against the interior wall of the pipe; and if the forward end of the pipe is adjacent the stiffback clamp, expanding an internal stiffback support positioned in a selected space relationship with the stiffback clamp against the interior wall of the pipe.

Claim 26

An improved method of bending pipe according to claim 20, including at some point prior to the step of increasing the upward forces on the forward end of the stiffback sufficient to pivot the stiffback, the step of expanding an internal pin-up support and an internal stiffback support inside the pipe and providing sUpport for portions of the interior wall of the pipe at locations spaced from the mandrel.