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Adjustable built-up stair

  • US 5,134,820 A
  • Filed: 09/19/1990
  • Issued: 08/04/1992
  • Est. Priority Date: 10/16/1990
  • Status: Expired due to Fees
First Claim
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1. A stair assembly, including an upper end stair unit, a lower end stair unit and a plurality of intermediate stair units connected in series therebetween, wherein said intermediate stair units each comprise:

  • a substantially T-shaped plate having a cross arm portion and a base portion extending from the cross arm portion to form a T-shape, said T-shaped plate including two pairs of elongated slots in said base portion;

    a holder plate connected to said T-shaped plate by means of nuts and bolts, said bolts extending through said elongated slots;

    a unitary socket extending downwardly from said cross arm portion;

    a unitary reinforcing bottom block portion extending downwardly from said base portion and horizontally from said unitary socket;

    a stepped hole centrally located in said cross arm portion; and

    a plurality of tread board bolt holes located bilaterally on said base operation for the connected thereto of a tread board,wherein said holder plate comprises a bolt sleeve having a vertical cutting, and two toothed nuts and a ratchet washer mounted on the bolt sleeve, and said ratchet washer is retained between said two toothed nuts and comprises an inner projection set in said vertical cutting of said holder plate, andwherein said socket and said bolt sleeve of said holder plate comprise internally a division board each having a bolt hole therethrough for the insertion therethrough of a bolt from said stepped hole to secure two intermediate stair units together when the bolt sleeve of the holder plate of one intermediate stair unit is inserted in the unitary socket of another intermediate stair unit.

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