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Stepping stool with elevating platform and controls

  • US 3,963,096 A
  • Filed: 06/09/1975
  • Issued: 06/15/1976
  • Est. Priority Date: 06/09/1975
  • Status: Expired due to Term
First Claim
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1. In a stepping stool, the combination of a hollow boxlike base mounted upon three casters, a top wall of said base having an opening therethrough, a mechanism inside said base protruding upwardly through said opening and having an elevating platform secured thereupon, a post mounted on said platform, a table panel mounted on an upper end of said post, and control means for operating said mechanism to raise or lower said platform, said mechanism including an electric motor attached to an extension cord and plug, a gear reducer driven by said motor driving a gear on an output shaft of said reducer, said gear driving a second gear having a threaded central opening engaged on a vertical screw shaft, said second gear being retained against vertical travel by stationary arms above and below said second gear, a keyway along said screw shaft engaging a stationary lug whereby said screw shaft moves vertically when said second gear is rotated, said keyway extending along a longitudinal central portion of said screw shaft, opposite ends of said screw shaft forming stops for said lug traveling in said keyway, said screw shaft being shorter than a height of said base, a lower end of said screw shaft clearing a floor when said platform is at a lowest elevation, said second gear and said lug engaging said screw shaft being within an upper portion of said hollow base, compression coil springs being fitted between said casters and said base, said casters extending lower than a lower rubber edge of said base when said springs are relaxed in extended positions, said control means comprising a two switch unit mounted on said table panel, said unit being in an electric circuit with said motor and a power source.

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