Apparatus for belling ends of conduit or the like

Claim 1

In apparatus for at least semi-automatically belling a first end of thermoplastic conduit for conformingly receiving a second end of conduit, including: a. heating means for at least locally heating said first end of said conduit; b. support means for supporting said conduit; and c. insert means for inserting an insertable mandrel for expanding said end to thereby bell said end to have a predetermined set of internal dimensions for receiving therewithin said second end of conduit having a predetermined set of external dimensions that conformingly mate with said internal dimensions: The improvement comprising said mandrel being an expandable insertable mandrel having a ridge protruding about its periphery for defining a groove having any predetermined cross sectional shape on the interior of said first end for receiving a seal means intermediate said fiRst end and said second end; said expandable insertable mandrel being connected with said insert means for insertion within said first end of said conduit without requiring elastic response of softened walls of said first end of said conduit in contracting around said ridge; said mandrel being expansible after insertion within said first end of said conduit for belling said first end, and collapsible after said belling and before withdrawal from said first end; said mandrel being connected with said insert means also for withdrawal from said first end of said conduit; said expandable mandrel comprising: d. a plurality of at least three elongate pieces having a predetermined peripheral radius of curvature that is the same as said second end of said conduit; said plurality of pieces of said expandable mandrel having respective portions of a ridge extending peripherally thereabout for forming said groove in the belled first end for receiving a seal means for sealing against said second end that is subsequently inserted thereinto; said pieces having a radius in a retracted position during insertion and withdrawal less than the radius of said first end of said conduit before belling, and being expansible after insertion within said first end to a radius in a fully expanded and belling position that is greater than said radius of said first end for belling said first end and forming a sealing groove therewithin; said pieces having a normal discontinuity when expanded into their fully expanded position; e. mounting means holding said plurality of pieces assembled in said retracted position and adapted for allowing radially outward expansion thereof into said belling position after insertion within said first end of said conduit; f. a central bore having a first frustoconically shaped bore opposite said mounting means for receiving a swage means; g. a central shaft disposed in said central bore and extending out of said first frusto-conically shaped bore; h. swage means disposed on said central shaft and movable longitudinally thereof for expanding said plurality of pieces radially outwardly into said belling position; said swage means having a frusto-conical shape adapted to conformingly fit said first frusto-conically shaped bore when fully seated thereinto for forming the belled first end; i. forcing means for forcing relative movement between said swage means and said pieces after insertion within said first end of said conduit to fully seat said swage means in and withdraw said swage means from said first frusto-conically shaped bore for collapsing said mandrel before withdrawal; said forcing means being connected with said swage means and said mounting means; j. smoothing means for smoothing out the interior surface of the final belled end and removing irregularities caused by said normal discontinuities of the expansibly mounted pieces when they are expanded outwardly into their fully expanded position by the fully seated swage means; and k. retraction means for effecting retraction of said pieces radially inwardly as said swage means is withdrawn from its fully seated position; such that said mandrel can be expanded to define a bell and a groove of any cross sectional shape, even square, since said conduit does not have to be slipped over said expansible mandrel when fully expanded.