Internal pipe supporting mandrel

Claim 2

An improved internal pipe supporting mandrel for use in a machine having a bending die and a stiffback, comprising: an elongated upper pipe-engaging assembly including at least one elongated inflatable bag mounted longitudinally along the upper assembly for providing internal support to the area of the pipe which is in contact with the bending die during the bending process; an elongated lower pipe-engaging assembly for engaging at least a part of the internal surface of the pipe in the area of the pipe which is in contact with the stiffback; and means for moving the upper and lower assemblies away from each other and thereby forcing the upper and lower assemblies into engagement with the pipe.

Claim 3

An improved internal pipe supporting mandrel according to claim 1, including means for inflating the inflatable bag to a selected pressure.

Claim 4

An improved internal pipe supporting mandrel according to claim 1, including means for moving the mandrel longitudinally along within the supporting surface, the moving means depending from the upper assembly so that they are in contact with the supporting surface when the upper and lower assemblies are contracted toward each other and are not in contact with each other when the assemblies are expanded away from each other.

Claim 5

An improved internal pipe supporting mandrel according to claim 1, wherein the upper assembly includes an elongated, longitudinally flexible, transversely plano-convex foundation assembly supporting a resiliently compressible pipe-engaging material enveloping a plurality of elongated inflatable bags.

Claim 6

An improved internal pipe supporting mandrel according to claim 4, wherein the plurality of inflatable bag are constructed to be filled with hydraulic fluid and are hydraulically interconnected in selected sets so that the pressures of the fluid supplied to the various sets of the bags can be varied.

Claim 7

An improved internal pipe supporting mandrel according to claim 1, wherein the lower assembly includes an elongated, longitudinally flexible, transversely plano-convex foundation assembly supporting pipe engaging means.

Claim 8

An improved internal pipe supporting mandrel according to claim 1, wherein the means for moving the upper and lower assemblies apart from each other and into engagement with the pipe include: opposing cam surfaces and shoulders mounted on the upper and lower assemblies at selected locations intermediate their lengths; at least one toggle bar mounted for horizontal movement between the opposing cam surfaces and shoulders at each location, each toggle bar including opposing surfaces for engaging the opposing cam surfaces and shoulders; and means for moving the toggle bars selectively horizontally whereby the upper and lower assemblies are moved away from each other by the toggle bars engaging the cam surfaces and thereby the shoulders and the toggle bars form a sturdy, continuous mechanical support between the upper and lower assemblies when the assemblies are in engagement with the pipe.

Claim 9

An improved internal pipe supporting mandrel comprising: an upper assembly for providing support to the interior of the upper wall of the pipe along a preselected length thereof from the apex of the pipe to preselected transverse points either side thereof, the upper assembly including at least one inflatable bag for maintaining a constant pressure against the interior of a selected longitudinal segment of the upper wall of the pipe; a lower assembly for providing support to the interior of the lower wall of the pipe along the preselected length thereof from the nadir of the pipe to preselected transverse points either side thereof; and means secured to the upper assembly and to the lower assembly for selectively moving the assemblies away from and toward each other and into and out of contact with interior of the wall of the pipe.

Claim 10

An improved internal pipe supporting mandrel comprising: an upper assembly for providing support to the interior of the upper wall of the pipe along a preselected length thereof from the apex of the pipe to preselected transverse points either side thereof, the upper assembly including at least one inflatable bag for maintaining a constant pressure against the interior of a selected longitudinal segment of the upper wall of the pipe; a lower assembly for providing support to the interior of the lower wall of the pipe along the preselected length thereof from the nadir of the pipe to preselected transverse points either side thereof; and means secured to the upper assembly and to the lower assembly for selectively moving the assemblies away from and toward each other and into and out of contact with interior of the wall of the pipe.

Claim 11

An improved internal pipe supporting mandrel according to claim 8, including means for moving the mandrel into, along and out of the pipe depending from the upper assembly whereby the means for moving the mandrel are in contact with the interior of the wall of the pipe when the upper and lower assemblies are contracted and are not in contact with the pipe when the upper and lower assemblies are expanded.

Claim 12

An improved internal supporting mandrel according to claim 8, wherein the upper assembly includes: an elongated, longitudinally flexible, transversely plano-convex foundation assembly; a resiliently compressible pipe engaging material having a plurality of holes longitudinally therethrough attached to the convex surface of the foundation; an elongated hydraulically inflatable bag held in each of the holes in the resiliently compressible material, the bags being hydraulically interconnected in selected sets.

Claim 13

An improved internal pipe supporting mandrel according to claim 8, including an internal expansible and contractible support assembly associated with and spaced from each end of the mandrel to provide support for the internal wall of the pipe at locations spaced from the mandrel.

Claim 14

An improved internal pipe supporting mandrel according to claim 8, wherein the lower assembly includes: a plurality of substantially plano-convex support elements; a plurality of elongated steel string strips secured to each of the support elements around the outer convex surfaces thereof; and a plurality of resiliently compressible pipe engaging elements secured to the strips.

Claim 15

An improved internal pipe supporting mandrel according to claim 8, wherein the means for selectively moving the upper and lower assemblies toward and away from each other includes: cam surfaces attached to each of the upper and lower assemblies; and means for selectively moving into contact with the cam surfaces and forcing apart the cam surfaces and the upper and lower assemblies attached thereto.

Claim 16

An improved internal pipe supporting mandrel comprising: at least one elongated, planar rectangularly shaped, flexible support member; plano-convex end plates secured to each end of the elongated support member; a plurality of curved support elements secured to the elongated support member between the end plates with a relatively small space between each of the curved support elements for longitudinal flexibility; the elongated support member and the plurality of of curved support elements conjunctively forming a foundation assembly; a plurality of elongated back-up strips extending longitudinally along the convEx exterior of the plurality of curved support elements; a resiliently compressible material extending longitudinally along the convex exterior of the plurality of the curved support elements and the back-up strips, the resiliently compressible material having a plurality of holes longitudinally therethrough and presenting a transversely convex exterior along its length with a plurality of receiving slots cored out of its exterior surface; a plurality of hydraulically inflatable bags held in holes in the resiliently compressible material and extending through holes in the end plates; a plurality of elongated tie-bars secured to the end plates and extending through holes in the resiliently compressible material; and a plurality of elongated surface integrating strips secured to the end plates and extending throughout the length of the resiliently compressible material in the receiving slots therein.

Claim 17

An improved internal pipe supporting mandrel comprising: at least one elongated, planar rectangularly shaped, flexible support member; plano-convex end plates secured to each end of the elongated support member; a plurality of curved support elements secured to the elongated support member between the end plates with a relatively small space between each of the curved support elements for longitudinal flexibility; the elongated support member and the plurality of of curved support elements conjunctively forming a foundation assembly; a plurality of elongated back-up strips extending longitudinally along the convEx exterior of the plurality of curved support elements; a resiliently compressible material extending longitudinally along the convex exterior of the plurality of the curved support elements and the back-up strips, the resiliently compressible material having a plurality of holes longitudinally therethrough and presenting a transversely convex exterior along its length with a plurality of receiving slots cored out of its exterior surface; a plurality of hydraulically inflatable bags held in holes in the resiliently compressible material and extending through holes in the end plates; a plurality of elongated tie-bars secured to the end plates and extending through holes in the resiliently compressible material; and a plurality of elongated surface integrating strips secured to the end plates and extending throughout the length of the resiliently compressible material in the receiving slots therein.

Claim 18

An improved internal pipe supporting mandrel according to claim 14, including: a plurality of upper jaw members attached to the underside of the elongated support member transversely intermediate its length and presenting downwardly facing cam surfaces and shoulders; at least one toggle bar pivotally linked to each jaw member; a plurality of lower jaw members, each of which is pivotally linked to a toggle bar, and which presents upwardly facing cam surfaces and shoulders and a downwardly facing convex surface; each toggle bar includes surfaces for engaging the cam surfaces and shoulders of the upper and lower jar members; a plurality of elongated strips secured to and extending longitudinally along the convex exterior of the lower jar member; a plurality of pipe engaging resiliently compressible elements attached to the elongated strips of the lower jar member; and at least one cylinder and piston assembly operatively connected to each toggle bar for moving the toggle bar.