Patents by Inventor Milton Crystal

Milton Crystal 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: 3936519
    Abstract: An automated system for fabricating a lead pencil in which the lead is securely bonded to a sheath formed of foam plastic material and having a smooth skin. In the system, individual pieces of lead which are pre-treated with a heat-activatable adhesive layer, are sequentially fed into an extrusion die in which the lead is ensheathed by molten foam plastic material whose heat serves to activate the adhesive. The string of ensheathed lead pieces emerging from the die are advanced through a sizing jig in a cooling station wherein the diameter of the sheath is rendered uniform and the surface thereof is formed into a smooth skin, the sheath being rigidified in the station and the activated adhesive being set to strongly bond the lead to the sheath. The resultant rod is fed to a cut-off station which serves to sever the rod into individual pencils.
    Type: Grant
    Filed: April 24, 1974
    Date of Patent: February 3, 1976
    Inventor: Milton Crystal