we designed three prototype units and tested them extensively . the first two exposed safety hazards and some discomforts , which we were able to overcome . the third prototype is the one we will use as our production model . the deck part number 35 sheet 3 / 9 with sixteen 9 mm diameter holes and one 11 mm diameter hole . a four holes in each rear corner for the two swivel casters part number 1 fastened with four parts number 4 and 12 ( bolts & amp ; nuts ). four holes in the center just forward of the caster holes are for two u bolts part number 13 to fasten the seat shaft assembly with mounting plate and nuts . four holes at the front of the deck ( two on each side ) are for the two tow tubes , sheet 1 / 9 part number 2 . the tow tubes are made from ¾ ″ emt electrical conduit 222 mm long with a ¼ ″ body universal coupler hex end pressed into one end of the tube and a ½ ″ ipt plug threaded flush to the other end . two 9 mm holes drilled 10 mm from each end to fasten the tube to the deck with two part number 3 curved weld nuts round base curved flange up to conform to the outside circumference of the od of the tube along with two joint connector bolts . the seat shaft assembly sheet 2 / 9 part number 21 is reworked with a piece of 1 ″ emt electrical conduit 150 mm long as the base . there is a groove rolled in 25 mm from each end 0 . 5 mm deep using a tubing cutter with a restrictor roller wheel in place of the cutter wheel . the grooves are to allow the two u bolts to fit over the tubes and to hold the assembly centered . the seat shaft is cut at the bottom with a 1 { fraction ( 3 / 16 )}″ diameter metal hole saw centered ½ ″ from the bottom . the hole is open at the bottom to be set over the tube centered and welded in place . two gussets , one on each side of the shaft made from ½ ″× ½ ″ square steel tube cut at 45 ° on each end welded to the ends of the base tube and to the shaft below the 1 ″ clamp part number 20 . the clamp is welded in place 105 mm from the bottom of the shaft assembly to the bottom of the clamp with the tabs clamped together and facing the rear . the seat shaft support sheet 1 / 9 is made up of part number 15 , clevis nipple ¼ ″ ip × 060 mm long . threaded one end with a clevis cut 3 mm wide × 20 mm deep on the other end . a ¼ ″ diameter hole drilled at right angle to the clevis centered 9 mm from the end . the clevis straddles the tab on the clamp and is held in place with a ½ ″ diameter × ⅝ ″ long roll pin pressed through the holes in the clevis and the clamp tabs . the treaded end is screwed into part number 6 coupler . the parts 15 and 16 have a total length of 105 mm , which can be adjusted by screwing them together or apart . part number 24 , ¼ ″ ip × 38 mm long running thread connects part number 7 coupler plug to part number 16 a 45 ° ¼ ″ ip coupling . the other end of the coupling is connected to the deck through hole y tapped to ¼ ″ ip . with a ¼ ″ ip nipple running tread × 45 mm long . two ½ ″ ip × 1⅜ ″ od flat washers , one on top of the deck and one on the bottom of the deck tightened with a ¼ ″ ipt locknut . the y hole is threaded so the nipple fits tight in the hole without having any lateral motion . the seat plate part number 25 was reworked with the armrest tube ½ ″ emt electrical conduit 32 ″ long . a 10 ″ stub bent up on each end , centered on and welded to the bottom of the plate just behind the seat shaft hole . the armrest part number 36 is oak hardwood , 1 ″ thick × 2 ″ wide × 6½ ″ long . a slot is cut in the center bottom ½ ″ wide × ½ ″ deep full length to accept the ½ ″× ½ ″ steel tube part number 33 . the tube has a ¼ ″ diameter hole drilled at one end centered ¼ ″ from the back end . the stub ends of the ½ ″ thin wall tube are slotted to ½ ″ wide and ½ ″ deep with a ¼ ″ diameter hole 5 mm from the top and 5 mm from the back to accept the ½ ″ square tube and fasten with part number 22 roll pin . the bellows 1¼ ″ diameter × 1 ″ long sump pump corrugated black plastic hose . a plastic plug is fitted to one end with a ½ ″× ½ ″ square hole in the center to fit over the ½ ″× ½ ″ steel tube . sheet 8 / 9 is a list of our part numbers and sheet 9 / 9 is a list of suppliers / manuafactures and their part numbers .
the dude tandem has been developed to assist a companion of a person in a motorized wheelchair or scooter to travel with them at the rear of their vehicle on a seat . it will relieve the companion of any discomfort or fatigue from walking and trying to keep up . the dude tandem is a new device , which has been welcomed by the public as a much needed convenience .