Apparatus for belling plastic pipe

Claim 2

In an apparatus for belling an end of a thermoplastic pipe, the combination of a belling head; means for positioning a pipe in axial alignment with said belling head comprising endless conveyor means arranged to move the pipe in a direction which is transverse both to the length of the pipe and said belling head, and means at the location of said belling head for receiving the pipe on said conveyor means, aligning the pipe with said belling head, and supporting the pipe in the resulting position of alignment; power means for effecting relative axial movement between said belling head and the adjacent end of the pipe to engage the belling head and pipe during belling to separate the belling head and pipe after belling; means for heating said end of the pipe to a softening temperature prior to engagement between said end and said belling head; and means for cooling said end of the pipe while the same is still engaged with said belling head.

Claim 3

The combination defined in claim 1, wherein said endless conveyor means is continuously driven; and said means for positioning the pipe comprises stop means movable between a retracted position, out of the path of travel of pipe on the conveyor means, and an active position, in which the stop means is disposed in the path of travel of the pipe in a location to engage and stop the pipe in general alignment with the belling head.

Claim 4

The combination defined in claim 2, wherein the axis of said belling head is spaced above the axis of a pipe when the pipe is supported on said conveyor means at the location of said belling head; and said means for receiving, aligning and supporting the pipe comprises lift means arranged to lift a pipe engaged by said stop means into axial alignment with said belling head.

Claim 5

The combination defined in claim 1, wherein said means for heating said end of the pipe comprises an annular heater structure dimensioned to surround said end of the pipe, the combination further comprising second power means for effecting relative movement between the pipe and said heater structure to establish operative positioning thereof.

Claim 6

The combination defined in claim 4, wherein said heater structure is mounted for axial movement into and out of surrounding relation with said end of the pipe.

Claim 7

The combination defined in claim 5, wherein said endless conveyor means is continuously driven; the combination further comprising stop means movable between a retracted position, out of the path of travel of pipe on the conveyor means, and an active position, in which the stop means is disposed in the path of travel of pipe on the conveyor means in a location to engage and stop the pipe when the same is axially aligned with said heater structure, the pipe being rotated by said conveyor means while in engagement with said stop means.

Claim 8

The combination defined in claim 4, wherein said heater structure comprises two generally semi-circular units mounted for movement between operative positions, in which the two units cooperate to form an annular structure, and inactive positions, in which the two units are spaced from each other by a distance adequate to allow free lateral passage of the pipe; and said second power means is arranged to move said generally semi-circular heater units between said operative and inactive positions.

Claim 9

The combination defined in claim 1, wherein said belling means comprises mandrel body means having a nose and a frusto-conical surface disposed with its small end toward said nose, and a plurality of transversely arcuate slip segments disposed in a circular series about said frusto-conical mandrel surface, said segments being shorter than said frusto-conical mandrel surface, having inner surfaces in sliding engagement with said frusto-conical mandrel surface, and having arcuate outer surfaces which cooperate to define a cylindrical surface of a diameter equal to the desired inner diameter for the bell to be formed on the pipe, when said segments occupy a given axial position on said frusto-conical mandrel surface; relative axial movement in a direction to insert said belling head into the pipe causing said segments to engage said end of the pipe along said frusto-conical mandrel surface to said given axial position; relative axial movement in the opposite direction tending to cause said segments to slide along said frusto-conical mandrel surface toward the nose of said mandrel body means, because of engagement of said segments with the pipe, whereby the assembly of slip segments is contracted to free the same from the pipe.

Claim 10

The combination defined in claim 1, wherein said belling head is mounted for axial movement toward and away from said end of the pipe when the pipe is supported in axial alignment therewith; and said cooling means comprises an annular coolant discharge device mounted for movement with said belling head and disposed concentrically therewith, the dimension of said coolant discharge device being such that said coolant device surrounds said end of the pipe when said belling head is operatively engaged with the pipe.

Claim 11

In an apparatus for belling an end of a thermoplastic pipe, the combination of a belling head; means for positioning a pipe in axial alignment with said belling head; power means for effecting relative axial movement between said belling head and the adjacent end of the pipe to engage the belling head and pipe during belling and to separate the belling head and pipe after belling; means for heating said end of the pipe to a softening temperature prior to engagement between said end and said belling head; and means for cooling said end of the pipe while the same is still engaged with said belling head, said belling head comprising mandrel body means having a nose which is directed toward said end of the pipe when the pipe is axially aligned with said belling head, and a frusto-conical surface tapering inwardly toward said nose, a plurality of slip segments arranged in a circular series about said frusto-conical mandrel surface, said segments being axially shorter than said frusto-conical mandrel surface, having inner surfaces in sliding engagement with said frusto-conical mandrel surface, and having outer surfaces which cooperate to define a cylindrical surface having a diameter equal to the inner diameter of the bell to be formed on the pipe when said segments are in a predetermined position spaced from the small end of said frusto-conical mandrel surface, and means for rEtaining said segments on said mandrel body means for free sliding movement axially along said frusto-conical mandrel surface, said outer surfaces of said segments constituting forming surfaces to shape said end of the pipe, said segments engaging the pipe during said relative axial movement and thereby being caused to slide on said frusto-conical mandrel surface axially away from the small end thereof to said predetermined position, relative axial movement between the pipe and said belling head in a direction to separate the same, aftr cooling of the belled end of the pipe, causing said segments to be pulled toward the small end of said frusto-conical surface by reason of engagement between rhe outer surfaces of said segments and the belled end of the pipe, and the taper of said frusto-conical mandrel surface then allowing said segments to move inwardly, whereby said belling head is freed from engagement with the belled end of the pipe.

Claim 12

In an apparatus for belling an end of a thermoplastic pipe, the combination of a belling head; means for positioning a pipe in axial alignment with said belling head; power means for effecting relative axial movement between said belling head and the adjacent end of the pipe to engage the belling head and pipe during belling and to separate the belling head and pipe after belling; means for heating said end of the pipe to a softening temperature prior to engagement between said end and said belling head; and means for cooling said end of the pipe while the same is still engaged with said belling head, said belling head comprising mandrel body means having a nose which is directed toward said end of the pipe when the pipe is axially aligned with said belling head, and a frusto-conical surface tapering inwardly toward said nose, a plurality of slip segments arranged in a circular series about said frusto-conical mandrel surface, said segments being axially shorter than said frusto-conical mandrel surface, having inner surfaces in sliding engagement with said frusto-conical mandrel surface, and having outer surfaces which cooperate to define a cylindrical surface having a diameter equal to the inner diameter of the bell to be formed on the pipe when said segments are in a predetermined position spaced from the small end of said frusto-conical mandrel surface, and means for rEtaining said segments on said mandrel body means for free sliding movement axially along said frusto-conical mandrel surface, said outer surfaces of said segments constituting forming surfaces to shape said end of the pipe, said segments engaging the pipe during said relative axial movement and thereby being caused to slide on said frusto-conical mandrel surface axially away from the small end thereof to said predetermined position, relative axial movement between the pipe and said belling head in a direction to separate the same, aftr cooling of the belled end of the pipe, causing said segments to be pulled toward the small end of said frusto-conical surface by reason of engagement between rhe outer surfaces of said segments and the belled end of the pipe, and the taper of said frusto-conical mandrel surface then allowing said segments to move inwardly, whereby said belling head is freed from engagement with the belled end of the pipe.

Claim 13

The combination defined in claim 10, wherein the angle of taper of said frusto-conical mandrel surface is approximately 5* and said segments are restrained against axial movement relative to said frusto-conical mandrel surface, as the belled end of the pipe contracts during cooling, by their engagement with said mandrel surface.

Claim 14

The combination defined in claim 10, wherein each of said slip segments has opposite side faces; said segments are arranged in close side-by-side relation in said circular series; and said side faces of alternate ones of said slip segments in said series converge toward one end of said frusto-conical mandrel surfaces and said side faces of the others of said slip segments diverge in a direction toward said one end at approxiamtely the same angle as said side faces of said alternate segments converge, whereby adjacent side faces of mutually adjacent ones of said segments are generally parallel with each other, the extent of convergence and divergence of said side faces being greater than the circumferential distance between adjacent side faces of mutually adjacent ones of said segments when said segments are in said predetermined position on said frusto-conical mandrel surface, whereby formation of ridges on the inner surface of said end of the pipe by the edges of said segments as said belling head and the pipe are engaged is avoided.

Claim 15

The combination defined in claim 10, and further comprising a plurality of strips of resilient material each interposed between the side faces of a different adjacent pair of said slip segments, said strips maintaining said slip segments in predetermined circumferential relation to each other.

Claim 16

The combination according to claim 13, wherein said strips presenting outwardly facing, circumferentially narrow edges which form continuations of the outer surfaces of said slip segments when said slip segments are in said predetermined position.

Claim 17

Apparatus for forming a bell end on a thermoplastic pipe comprising a generally cylindrical belling head assembly; means to move said belling head into the end of a pipe generally axially aligned with the belling head to form the bell end, and means to heat the end of the pipe prior to belling the end; said belling head assembly comprising a tapered body; a plurality of slip segments, each of arcuate curvature, surrounding said body in closely adjacent circumferential relation to each other said slip segments being slidable along said body to an expanded position in which the slip segments define an outer surface approximately a surface of revolution of the same size and form as the interior of the bell end formed on the pipe, and a contracted position in which the outer surface is smaller than the interior of the bell end to facilitate separating the pipe from the belling head; each alternate slip segment on the body having opposite sides which converge in a direction toward one end of the body, and each of the oTher slip segments on the body having opposite sides which diverge in a direction toward said one end of the body; the extent of divergence and convergence being greater than the distance between facing side edges of adjacent slip segments, when said slip segments are in said expanded position; whereby, a ridge free interior bell end is formed on the pipe as a result of forcing the belling head axially into the pipe.

Claim 18

Apparatus for forming a bell end on a thermoplastic pipe comprising a generally cylindrical belling head assembly; means to move said belling head into the end of a pipe generally axially aligned with the belling head to form the bell end, and means to heat the end of the pipe prior to belling the end; said belling head assembly comprising a tapered body; a plurality of slip segments, each of arcuate curvature, surrounding said body in closely adjacent circumferential relation to each other said slip segments being slidable along said body to an expanded position in which the slip segments define an outer surface approximately a surface of revolution of the same size and form as the interior of the bell end formed on the pipe, and a contracted position in which the outer surface is smaller than the interior of the bell end to facilitate separating the pipe from the belling head; each alternate slip segment on the body having opposite sides which converge in a direction toward one end of the body, and each of the oTher slip segments on the body having opposite sides which diverge in a direction toward said one end of the body; the extent of divergence and convergence being greater than the distance between facing side edges of adjacent slip segments, when said slip segments are in said expanded position; whereby, a ridge free interior bell end is formed on the pipe as a result of forcing the belling head axially into the pipe.

Claim 19

Apparatus according to claim 15 wherein a filler strip of resilient material extends between the side edges of each adjacent slip segments; said filler strips, in said expanded position of said segments, presenting outwardly facing edges which form a continuation of slip segments at the spaces between segments.