Automated bending and belling of plastic pipe

Claim 2

Apparatus for at least semi-automatically (1) bending pre-cut segments of conduit to form elbows and (2) belling the ends of the elbows comprising: a. expansible belling mandrel and insert means for inserting said belling mandrel into said conduit to sealingly engage said end of said conduit; b. retaining means for retaining said belling mandrel in sealing engagement with said end of said conduit; c. pressurizing means for injecting a fluid under a controlled superatmospheric pressure to establish a superatmospheric pressure within said conduit to form a differential pressure across its walls; d. heating means for heating said segment of conduit to its softening temperature; e. expanding means for expanding said mandrel and said end at its softening temperature to form a belled end that is adapted for sealingly receiving a co-engaging end of said conduit inserted therewithin; f. jig means and bending means for bending said conduit at its softening temperature while maintaining said pressure differential across its walls; said bending means being adapted to at least semi-automatically bend the said conduit to said predetermined degree and radius of bend in conformance with said jig means to form a precision elbow with a minimum of distortion of its side walls because of the differential pressure thereacross; g. cooling means for cooling said precision elbow while maintaining said differential pressure and said conformance to said jig means; and h. an equalizing and releasing means for equalizing the pressure across the walls of the conduit, for releasing and removing said belling mandrel and for releasing said elbow from comforming engagement with said jig means.

Claim 3

The apparatus of claim 1 wherein: a. said heating means is positioned at a heating location through which said conduit is passed to heat said segment of conduit to its softening temperature; b. said cooling means is positioned at a second location through which said elbow is passed to cool said elbow; and c. moving means is provided for moving said segment of conduit through said heating and cooling locations; said pressurizing means for injecting said fluid being adapted to remain connected with said segment of conduit throughout its traverse and throughout operation of said heating and cooling means.

Claim 4

The apparatus of claim 1 wherein said pressurizing means a includes an external supply of fluid at superatmospheric pressure and said expansible mandrel comprises: a. a plurality of at least three pieces having a predetermined peripheral radius of curvature that is the same as said second end of said conduit; b. mounting means holding said plurality of pieces assembled and adapted for allowing radially outward expansion thereof; c. a central bore having a first frusto-conically shaped bore opposite said mounting means for receiving a swage means; d. a central shaft disposed in said central bore and extending out of said frusto-conically shaped bore; said central shaft having a passageway extending longitudinally therethrough for conducting a fluid interiorly of said conduit and connected with said external supply of said fluid; e. swage means disposed on said central shaft and movable longitudinally thereof for expanding said plurality of pieces radially outward, said swage means having a frusto-conical shape adapted to conformingly fit said frusto-conically shaped bore when fully seated thereinto for forming the belLed first end; f. forcing means for forcing relative movement between said swage means and said pieces to fully seat said swage means in and withdraw said swage means from said frusto-conically shaped bore; said forcing means being connected with said swage means and said mounting means for effecting the relative movement therebetween; g. smoothing means for smoothing out the interior surface of the final belled end and removing irregularities caused by normal discontinuities of the expansibly mounted pieces when they are expanded outwardly into their fully expanded position by the fully seated swage means; and h. retraction means for effecting retraction of said pieces radially inwardly as said swage means is withdrawn from its fully seated position.

Claim 5

The apparatus of claim 3 wherein said plurality of pieces of said expansible mandrel have a ridge extending peripherally thereabout for forming a groove in the belled first end for receiving a seal means for sealing against a second end that is inserted thereinto.

Claim 6

The apparatus of claim 3 wherein a receiving mold is provided; said receiving mold comprising a pair of tubular shells that conformingly fit together laterally to define an internal cavity of the desired shape and dimension; and wherein a means is provided for moving said pair of tubular shells laterally together for receiving a belled end and moving them apart to free said belled end.

Claim 7

The apparatus of claim 3 wherein said mounting means comprises a pivotal mounting for each of said pieces and said pieces pivot outwardly to accurately define said belled end in their fully expanded position.

Claim 8

The apparatus of claim 3 wherein said mounting means comprises respective track means and riders movable longitudinally thereof and said pieces move longitudinally of said track means radially outwardly into their fully expanded position.

Claim 9

The apparatus of claim 3 wherein said mounting means comprise respective parallelogram linkages such that said pieces retain their same relative orientation parallel to their central longitudinal axis as they are moved radially inwardly and outwardly.

Claim 10

The apparatus of claim 3 wherein said smoothing means comprises means for rotating said mandrel through a predetermined number of degrees.

Claim 11

The apparatus of claim 3 wherein said smoothing means comprises the same plurality of plugging sectors that are movable outwardly into the respective gaps between said plurality of pieces when said pieces are expanded radially outwardly into their fully expanded position by the fully seated swage means; said plugging sectors being retractable inwardly into recesses before said pieces are retracted radially inwardly to their retracted position; and expansion and retraction means for expanding and retracting said plugging sectors.

Claim 12

Apparatus for precision belling and bending of plastic conduit comprising: a. a rotatable means for moving a segment of conduit through a plurality of locations for carrying out a variety of cooperating functions, said rotatable means having a plurality of sections, the plurality being at least as great as the number of locations; each section including: i. pressurizing means for establishing a superatmospheric pressure within a segment of conduit, said pressurizing means being connected with a pressurized source of fluid having a pressure regulating means and including an expansible sealing belling mandrel for sealing emplacement at one end and another means for sealing emplacement at another end of said segment of conduit for controlling flow of fluid at each end of said segment of conduit; said pressurizing means being operable to maintain the superatmospheric pressure throughout said plurality of locations after said belling mandrel has been sealingly inserted within said end of said conduit and as said rotatable means is rotated through said plurality of locations; ii. clamping means for clamping each end of said segment of conduit, said clamping meAns having a fixed portion that is fixedly carried by said section and a movable portion that is movable along a predetermined arcuate path so as to effect a desired degree of bend and desired shape of said segment of conduit; iii. jig means having an interior wall of a desired finish for effecting an elbow having a desired finished surface; iv. belling mandrel and inserting means for inserting said belling mandrel into said conduit to sealingly engage the end of said conduit and form said belled end; said belled end being adapted to sealingly receive a co-engaging end of said conduit that is inserted therewithin; v. automatic bending means connected with said movable portion of said clamping means for bending said segment of conduit responsive to an actuation means, said bending means having holding means for holding a desired degree of bend once attained; vi. stop means for limiting the degree of bending that is automatically effected by said bending means; and vii. expanding means for expanding said expansible mandrel and forming said belled end; b. loading and unloading location for emplacing said segment of conduit within said clamping means and in alignment with said belling mandrel in a section and connecting said pressurizing means and for releasing said pressurizing means and said belling mandrel and taking a formed elbow from said clamping means; said loading and unloading location in combination with each said section including: i. means for releasing the pressure from within said conduit and disconnecting said pressurizing means therefrom; ii. release means for releasing and effecting withdrawal of said belling mandrel; iii. means for releasing, respectively, said holding means, said bending means, and said clamping means for taking a formed elbow therefrom; iv. means for re-connecting said pressurizing means with a subsequent condition for establishing pressure therewithin; and aligning said conduit with said belling mandrel for another throughput; means for inserting said belling mandrel into said conduit to sealingly engage the interior walls thereof; and v. means for effecting operation of said pressurizing means to inject said fluid and effect a differential pressure across the walls of said segment of conduit; c. heating location including heating means disposed peripherally downstream of said loading and unloading location for heating said segment of conduit intermediate its ends along a sufficient distance to form an elbow of the desired radius and for heating said end in which said expansible mandrel is inserted; said heating being effected to the softening temperature of said conduit; d. heating, belling and bending location disposed peripherally downstream of said heating location for belling said end of said conduit to a precision belled end and for bending the segment of said conduit at its softening temperature to a precision elbow; said heating and bending location including: i. second heating means for maintaining said segment of conduit at its softening temperature; and ii. actuation means for automatically actuating said bending means to bend the softened segment of conduit into conformance with said jig means and said stop means and into a precise degree of bend and shape and simultaneously actuating expanding of said expansible mandrel for forming said belled end; and e. at least one cooling location having means for subjecting said precision elbow to a cooling fluid to cool it below its softening temperature and into a flexible state before it reaches said loading and unloading location.

Claim 13

Apparatus for precision belling and bending of plastic conduit comprising: a. a rotatable means for moving a segment of conduit through a plurality of locations for carrying out a variety of cooperating functions, said rotatable means having a plurality of sections, the plurality being at least as great as the number of locations; each section including: i. pressurizing means for establishing a superatmospheric pressure within a segment of conduit, said pressurizing means being connected with a pressurized source of fluid having a pressure regulating means and including an expansible sealing belling mandrel for sealing emplacement at one end and another means for sealing emplacement at another end of said segment of conduit for controlling flow of fluid at each end of said segment of conduit; said pressurizing means being operable to maintain the superatmospheric pressure throughout said plurality of locations after said belling mandrel has been sealingly inserted within said end of said conduit and as said rotatable means is rotated through said plurality of locations; ii. clamping means for clamping each end of said segment of conduit, said clamping meAns having a fixed portion that is fixedly carried by said section and a movable portion that is movable along a predetermined arcuate path so as to effect a desired degree of bend and desired shape of said segment of conduit; iii. jig means having an interior wall of a desired finish for effecting an elbow having a desired finished surface; iv. belling mandrel and inserting means for inserting said belling mandrel into said conduit to sealingly engage the end of said conduit and form said belled end; said belled end being adapted to sealingly receive a co-engaging end of said conduit that is inserted therewithin; v. automatic bending means connected with said movable portion of said clamping means for bending said segment of conduit responsive to an actuation means, said bending means having holding means for holding a desired degree of bend once attained; vi. stop means for limiting the degree of bending that is automatically effected by said bending means; and vii. expanding means for expanding said expansible mandrel and forming said belled end; b. loading and unloading location for emplacing said segment of conduit within said clamping means and in alignment with said belling mandrel in a section and connecting said pressurizing means and for releasing said pressurizing means and said belling mandrel and taking a formed elbow from said clamping means; said loading and unloading location in combination with each said section including: i. means for releasing the pressure from within said conduit and disconnecting said pressurizing means therefrom; ii. release means for releasing and effecting withdrawal of said belling mandrel; iii. means for releasing, respectively, said holding means, said bending means, and said clamping means for taking a formed elbow therefrom; iv. means for re-connecting said pressurizing means with a subsequent condition for establishing pressure therewithin; and aligning said conduit with said belling mandrel for another throughput; means for inserting said belling mandrel into said conduit to sealingly engage the interior walls thereof; and v. means for effecting operation of said pressurizing means to inject said fluid and effect a differential pressure across the walls of said segment of conduit; c. heating location including heating means disposed peripherally downstream of said loading and unloading location for heating said segment of conduit intermediate its ends along a sufficient distance to form an elbow of the desired radius and for heating said end in which said expansible mandrel is inserted; said heating being effected to the softening temperature of said conduit; d. heating, belling and bending location disposed peripherally downstream of said heating location for belling said end of said conduit to a precision belled end and for bending the segment of said conduit at its softening temperature to a precision elbow; said heating and bending location including: i. second heating means for maintaining said segment of conduit at its softening temperature; and ii. actuation means for automatically actuating said bending means to bend the softened segment of conduit into conformance with said jig means and said stop means and into a precise degree of bend and shape and simultaneously actuating expanding of said expansible mandrel for forming said belled end; and e. at least one cooling location having means for subjecting said precision elbow to a cooling fluid to cool it below its softening temperature and into a flexible state before it reaches said loading and unloading location.

Claim 14

The apparatus of claim 11 wherein said pressurizing means includes an external supply of fluid at superatmospheric pressure and said expansible mandrel comprises: a. a plurality of at least three pieces having a predetermined peripheral radius of curvature that is the same as said second end of said conduit; b. mounting means holding said plurality of pieceS assembled and adapted for allowing radially outward expansion thereof; c. a central bore having a first frusto-conically shaped bore opposite said mounting means for receiving a swage means; d. a central shaft disposed in said central bore and extending out of said frusto-conically shaped bore; said central shaft having a passageway extending longitudinally therethrough for conducting a fluid interiorly of said conduit and connected with said external supply of said fluid; e. swage means disposed on said central shaft and movable longitudinally thereof for expanding said plurality of pieces radially outward, said swage means having a frusto-conical shape adapted to conformingly fit said frusto-conically shaped bore when fully seated thereinto for forming the belled first end; f. forcing means for forcing relative movement between said swage means and said pieces to fully seat said swage means in and withdraw said swage means from said frusto-conically shaped bore; said forcing means being connected with said swage means and said mounting means for effecting the relative movement therebetween; g. smoothing means for smoothing out the interior surface of the final belled end and removing irregularities caused by normal discontinuities of the expansibly mounted pieces when they are expanded outwardly into their fully expanded position by the fully seated swage means; and h. retraction means for effecting retraction of said pieces radially inwardly as said swage means is withdrawn from its fully seated position.

Claim 15

The apparatus of claim 11 wherein said plurality of pieces of said expansible mandrel have a ridge extending peripherally thereabout for forming a groove in the belled first end for receiving a seal means for sealing against a second end that is inserted thereinto.

Claim 16

The apparatus of claim 11 wherein a receiving mold is provided; said receiving mold comprising a pair of tubular shells that conformingly fit together laterally to define an internal cavity of the desired shape and dimension; and wherein a means is provided for moving said pair of tubular shells laterally together for receiving a belled end and moving them apart to free said belled end.

Claim 17

The apparatus of claim 11 wherein said mounting means comprises a pivotal mounting for each of said pieces and said pieces pivot outwardly of accurately define said belled end in their fully expanded position.

Claim 18

The apparatus of claim 11 wherein said mounting means comprises respective track means and riders movable longitudinally thereof and said pieces move longitudinally of said track means radially outwardly into their fully expanded position.

Claim 19

The apparatus of claim 11 wherein said mounting means comprises respective parallelogram linkages such that said pieces retain their same relative orientation parallel to their central longitudinal axis as they are moved radially inwardly and outwardly.

Claim 20

The apparatus of claim 11 wherein said smoothing means comprises means for rotating said mandrel through a predetermined number of degrees.

Claim 21

The apparatus of claim 11 wherein said smoothing means comprises the same plurality of plugging sectors that are movable outwardly into the respective gaps between said plurality of pieces when said pieces are expanded radially outwardly into their fully expanded position by the fully seated swage means; said plugging sectors being retractable inwardly into recesses before said pieces are retracted radially inwardly to their retracted position; and expansion and retraction means for expanding and retracting said plugging sectors.