The idea centers around a mechanical means of climbing stairs. I've got a feeling that I'm going over old ground perhaps you can warn me. In climbing stairs one presses down on one foot and in so doing move the body forward and up, one then places the other foot on a higher step presses this down and remove the first foot. I am trying to simulate this by using two runners which lay on the steps seperated by two belts attached to each a 'foot'. One driven belt will push the object attached to the apparatus upwards ( think tank ) and the other will take over when the first reaches the limit of its transit. Now the nitty-gritty. The belts can be either reniforced 'rubber' toothed to be driven by gear wheel ( lighter loads ) or proper tracks of plastic links driven by a sprocket. The shoe is an rect. block with a hook type end elevation, the idea is that it will grip the step. When the shoe reaches the end of its travel it is held in a temp. latch. The force of the blocked motion will be utilised to operate a toggle switch this will push the common drive shaft to one side releasing the dog clutch on the first belt driving sprocket ( the belt of course will have a one direction only ratchet mechanism ) and pressing in to the second belt's dog clutch ( a spring will allow movement ) force a cone into the centre of the second sprocket increasing effective diam. ( DAF system, take up idler required. ) The result of all this complicated manouvering will be to reduce the dead time needed to bring the second shoe out from its tunnel and to engage with the available higher step ( remember mech.adv. demands slow speeds. ) As the two engaged shoes now block the system the forces generated can operate another switch which (1) releases the first shoe which can now proceed over the bottom spocket and move upwards thru its tunnel to be utilised at a further stage (2) flips the drive shaft back to the origional position ( note splining on the middle of the shaft to preserve drive during lateral movement. The action is now the mirror of the first stage. The actual originating drive can be by hand, using a telescopic lever which can give the individual mech.adv. required or by elec. motor and bat. If the system is incorperated in a suitcase then the wheels can be used to drive a gen.for charging. Descent is the reverse, ratchets reversed, top latches and note that the shoe will intially make contact with the underside of the step, this will be sufficient to operate switch, but the apparatus must drop to the next step for a firm grip. Comments?