Patents by Inventor Haison Yuen

Haison Yuen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5002153
    Abstract: An improved ladder structure comprising a pair of stiles, a plurality of rungs, and a plurality of brackets. Wherein, each bracket consisting of two parallel arms, with a securing hole formed on each parallel arm, and a connecting surface running between the parallel arms, with a rivet hole formed thereon. Each rung has a pair of insertion recesses formed on either end, each recess being diametrically opposed with the other. At a predetermined distance inwards form each insertion recess is formed an insertion slot. Both the insertion recesses and insertion slots pass through one of a pair of through-holes formed internally on opposing arcuate surfaces of a rung, extending from one end to the other. Whereby, on either end of a rung, a pair of opposing brackets are inserted into corresponding insertion slots and insertion recesses, and subsequently secured in place by insertion of dowel pins into the through-holes.
    Type: Grant
    Filed: July 30, 1990
    Date of Patent: March 26, 1991
    Inventor: Haison Yuen
  • Patent number: 4947959
    Abstract: A folding ladder comprising of four straight sections each consisting of two uprights and four rungs equally spaced. The sections are connected with insulating hinged joints which can be tightened immovable or loosened movable by means of a lever handle thus allowing the adjustment of the ladder into various configurations.
    Type: Grant
    Filed: March 14, 1989
    Date of Patent: August 14, 1990
    Inventor: Haison Yuen
  • Patent number: 4842098
    Abstract: The invention is an adjustable folding ladder that can be easily altered in its length and shape to adjust to the proper working height and angles for the user. With the fiber glass nylon hinges, the ladder is insulated to prevent the user from electrical shocks in the event the ladder comes into contact with electrical wiring.
    Type: Grant
    Filed: October 29, 1987
    Date of Patent: June 27, 1989
    Inventor: Haison Yuen