portions with a radius equal to that of the rollers the rollers are generally moved in unison but are permitted a small range of independent movement to insure locking of both rollers in the locking groove in the event of slight misalignments due to manufacturing tolerances application_number US 36862682 A description referring now to the drawings and to fig1 in particular a first pipe section in the form of an elbow generally designated by the numeral 10 is depicted the elbow has a two part body including an upper body portion 12 and a lower body portion 14 both of which are formed of aluminum in the preferred embodiment the upper and lower body portions 12 and 14 respectively are joined to each other by a plurality of bolts 16 and nuts 18 only one bolt 16 and nut 18 are shown in fig1 which extend through mutually aligned apertures not shown in the flanges 20 and 22 the flange 20 is formed on upper body portion 12 and the flange 22 is formed on the lower body portion 14 a gasket 21 is interposed between the flanges 20 and 22 to provide a seal between the upper and lower body portions 12 and 14 the gasket 21 also has aligned apertures not shown to accommodate the bolts 16 as perhaps suggested.