Method for bending pipe

Abstract

In the method an apparatus engages pre-cut lengths of heated thermoplastic pipe against a pair of eccentric wiper arms bending the pipes into elbows. The eccentric wiper arms have an eccentric portion and a constant radius portion. A bending form has an arcuate die adapted to hold a pre-cut length of pipe. Four such bending forms are radially connected to a rotation shaft which is journalled at each end to a support frame. A continuous supply of pre-cut lengths of pipe are transported through a heating chamber by a set of endless chains. Each pipe is then transferred to a bending form which is rotated by the shaft so that the cold end portions of each pipe engages the spaced apart and substantially parallel eccentric wiper arms. The wiper arms urge the end portions of each pipe length slightly beyond the outer edges of each arcuate die to compensate for the effect cooling has on each pipe length. Once the pipe is bent, the rotation of the bending form causes the pipe to drop into a tank of water. A pump circulates cooled water through the tank so the water is maintained at approximately 40.degree. Fahrenheit. When water is pumped into the tank enough water flow is created to urge the elbows toward a conveyor belt. Another pump creates water flow that urges the elbows onto the conveyor belt which removes the elbows from the tank and drops them in a storage bin.