I need a design for a pull out sofa bed for my camper. As you can see from the picture, I want to be able to pull the seat of the sofa out & up to have it flatten out into a bed. I understand that the pivot point on the back of the sofa is just a pin in a slider/slot but I can’t figure out how to make the hinge between the bottom & back work so that it doesn’t bind when converting but still butts up end to end when in the bed configuration. I can design the legs to support the free floating end of the bed configuration. The couch flattens out into a twin size bed & the hinges must be able to support the weight of an adult male. The cushions are 1/2” thick plywood covered in 3.5” of foam. I can fabricate supporting if need be. The final caveat is that the seat bottom of the couch must be able to fold up while in the couch position in order to access storage space under the couch.