Patent ID: 8714524

Claim:
A scissors-type lift assembly comprising: a base; a platform coupled to said base for movement between elevated and lowered states in which said platform and said base are distant and proximate, respectively; a pair of first and second scissor arms each having upper and lower ends respectively coupled to said platform and said base, said pair of scissor arms pivotably connected to each other intermediate their respective upper and lower ends about a central pivot axis; a first pulley arrangement having a plurality of first pulleys disposed about a first pulley shaft defining a first pulley axis with each of said first pulleys having a first belt engaging circumferential surface that is substantially flat; a second pulley arrangement having a plurality of second pulleys disposed about a second pulley shaft defining a second pulley axis with each of said second pulleys having a second belt engaging circumferential surface that is substantially flat, and said first and second pulley axes disposed in a pulley plane and having lateral movement relative to each other as said lift assembly is moved between its said elevated and lowered states; a spool rotatable about an axis fixed to said base; and a unitary belt guided through a path defined by said first and second pulleys with said belt having a first end engaged with said spool onto which said belt is wound and from which said belt is unwound and an opposing second end; said first pulley arrangement further including a plurality of independently rotatable first flange members disposed about said first pulley shaft with each of said first flange members extending outwardly beyond said first belt engaging circumferential surfaces of said first pulleys, and at least one of said first flange members disposed between each of said first pulleys to sandwich said respective first pulleys and to maintain said belt on said path and said first belt engaging circumferential surfaces about said respective first pulleys; and said second pulley arrangement further including a plurality of independently rotatable second flange members disposed about said second pulley shaft with each of said second flange members extending outwardly beyond said second belt engaging circumferential surfaces of said second pulleys, and at least one of said second flange members disposed between each of said second pulleys to sandwich said respective second pulleys and to maintain said belt on said path and said second belt engaging circumferential surfaces about said respective second pulleys.