Patents Assigned to Package Research Corp.
  • Patent number: 5092496
    Abstract: A dispenser for flowable materials, such as toothpaste, includes a hollow barrel in the form of a tube open at its lower end and closed at its upper end with the flowable material being inserted in the tube. A plunger which is also in the form of a hollow tube having a closed upper end, is telescopically arranged in the barrel. A seal is effected by a hinged peripheral rim on the outer surface of the piston near its upper end. The flow of the material forces the peripheral rim to pivot into sealing contact with the inner surface of the barrel.
    Type: Grant
    Filed: March 11, 1991
    Date of Patent: March 3, 1992
    Assignee: Package Research Corp.
    Inventors: Harold R. Gayle, William T. Wilkinson, Mario Boiardi