Scissor lift and drive mechanism therefor

Claim 1

A scissor lift and drive mechanism comprising means forming first and second platforms, means forming first and second pivotally interconnected pairs of scissor arms having first ends pivotally mounted in spaced parallel planes on said first platform, said last named means including means interconnecting at least one first end of each of said scissor arms for sliding movement toward the other first end to thereby close the gap therebetween and to extend the second ends of said arms away from the first ends and from said first platform to provide thereby a lifting action, said second platform being mounted on the second ends of said arms to be lifted thereby and including means mounting at least one of said second ends of said arms for sliding motion on said platforms to and from the other second end to accomodate closing of the second ends thereof as the same are activated into extended position, a cam roller interposed between the first and second ends of each of said scissor arms on one side thereof and having means thereon for permitting sliding motion along said arms toward the extremeties thereof when the same are lowered and toward the pivotal connection therebetween as the same are raised, first pulley means disposed on said first platform approximate to said other first end, second pulley means disposed on the second platform at a position approximate said other second end, said roller cam being disposed on that side of said scissor lift mechanism away from said first and second pulley means, third pulley means connected to said one second end, means for driving one of said first or third pulleys, cable means connected to said driven pulley and reeved about said cam roller and said second pulley means and thence about said third or first pulley means, respectively, and means connecting the end of said cable to the first or second platform, respectively.