Patents by Inventor Keith M. Macdonald

Keith M. Macdonald 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: 4938825
    Abstract: A laminated article, for example a bath or shower-tray, is manufactured by providing a preformed shell, for example a thermoformed acrylic sheet, which shell is placed in a mould, together with, if required, a reinforcing board, for example of chipboard or plywood. The mould is then closed and materials are injected into the mould cavity which react to form a reinforcing layer on the shell. Preferably, the injected materials comprise a polyol reactant and an isocyanate reactant which form a layer of rigid polyurethane foam. A reinforcing agent, for example glass fibre, and a blowing agent may also be introduced into the mould cavity.
    Type: Grant
    Filed: July 12, 1989
    Date of Patent: July 3, 1990
    Assignee: Armitage Shanks Limited
    Inventor: Keith M. Macdonald