Patents by Inventor Harm Boomsma

Harm Boomsma 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).

  • Chair with movable seat and backrest
    Patent number: 4789203
    Abstract: Chair comprising a support element, a seat and a backrest, the seat consisting of a foremost portion being rigidly connected to the support element and of a rear portion being pivotally connected to the support element and being supported by an arm at some distance from its pivot, said arm being positioned beneath the seat and carrying the backrest. Said arm being pivotally connected to the support element and being biased by a progressively acting spring member towards the position which the rear seat portion and the backrest are occupying in the unloaded state.
    Type: Grant
    Filed: February 13, 1987
    Date of Patent: December 6, 1988
    Assignee: Ahrend Groep N.V.
    Inventors: Eric van Zee, Harm Boomsma, Ronald Lewerissa, Jeroen Verbrugge