Abstract: A device is disclosed for coupling a drainpipe to a recreational vehicle discharge pipe fitting of the type having a terminal end portion with circular periphery and a plurality of locking pins extending outward radially from the periphery. The device employs a tubular member having a proximal end and a distal end. A drainpipe end portion of the tubular member terminating at the distal end has a complementary shape and size adapted to engage threadably an end of a corrugated drainpipe, while a fitting end portion of the tubular member terminating at the proximal end has a complementary shape and size adapted to engage telescopically a terminal end portion of the discharge pipe fitting.

Abstract: An adapter for coupling a corrugated drainpipe to recreational vehicle discharge pipe employs a tubular member having a discharge pipe end portion of a shape and size adapted to be placed over an outlet end of the discharge pipe, and a drainpipe end portion having a shape and size adapted to engage threadably an end of a corrugated drainpipe. A helically-shaped thread along the drainpipe end portion are sized and shaped complementary to conform to the corrugations of the corrugated drainpipe enables threaded engagement of the corrugated drainpipe.

Abstract: A coupler for interconnecting in fluid communication a pair of axially aligned flexible pipe ends, employs a tubular member for insertion between two sections of drainpipe to be coupled. A first thread is included on a first end portion of the tubular member for threaded engagement of a first one of the two sections of drainpipe, along with a second thread on a second end portion for threaded engagement of the second section. An integrally formed annular flanges in one form of the invention serves as a grip with which to manually screw the tubular member onto the drainpipe, while a cutback portion on the flange prevents misalignment of the coupled sections at the coupling when placed upon the ground. Tapered end pieces that screw onto each end to accommodate smaller drainpipe are provided in another form, with the threads of the tubular member matching the helically-corrugated plastic casing surface of conventional RV drainpipe.