The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 15, 1988
Filed:
Sep. 12, 1986
Richard M Berger, Midlothian, VA (US);
American Filtrona Corporation, Richmond, VA (US);
Abstract
A method and means for making an improved tobacco smoke filter is characterized by the production of longitudinally continuous grooves running from end-to-end in the peripheral surface of a smoke-impervious filter plug wrap with the grooves having a transverse cross-sectional area that varies as a function of longitudinal displacement. Smoke-impervious tipping surrounds the plug wrap to seal the grooves except for small ventilation holes in the tipping which permit communication between the grooves and the ambient air. In the preferred embodiment, the grooves are restricted toward the mouth end of the filter and the degree of restriction determines the direction of air and smoke flow in the grooves. The grooves are each preferably formed as two longitudinal sections of different cross-section.