This ordinary ladder has safety features to warn when it may be about to fall. It rings and flashes when it is standing at too acute or too obtuse an angle or when one of its ends starts to glide in relation to the building/ground. It also sounds when the pressure of the upper edge against its support lightens (risk of falling backwards).
The warning system is only activated when there is weight on one of the rungs.-- FarmerJohn, May 13 2005 US patent 6,657,547 http://patft.uspto....57547&RS=PN/6657547Sensing and warning system for ladder load [xaviergisz, May 16 2005] Fallen off a ladder recently [FJ]?-- wagster, May 13 2005 Not yet.-- FarmerJohn, May 13 2005 Me neither.
Kinda miss it...-- skinflaps, May 15 2005 Too much OSHA.-- Soterios, May 15 2005 random, halfbakery