Section 9--320. Buyer of Goods.
    (a) Buyer in ordinary course of business. Except as otherwise provided
  in  subsection (e), a buyer in ordinary course of business, other than a
  person buying farm products from a person engaged in farming operations,
  takes free of a security interest created by the buyer's seller, even if
  the security interest is perfected and the buyer knows of its existence.
    (b) Buyer  of  consumer  goods.  Except  as  otherwise   provided   in
  subsection  (e),  a  buyer of goods from a person who used or bought the
  goods for use primarily for  personal,  family,  or  household  purposes
  takes free of a security interest, even if perfected, if the buyer buys:
         (1) without knowledge of the security interest;
         (2) for value;
         (3) primarily  for  the  buyer's  personal,  family, or household
             purposes; and
         (4) before the filing  of  a  financing  statement  covering  the
             goods.
    (c) Effectiveness  of filing for subsection (b). To the extent that it
  affects the priority of a security interest over a buyer of goods  under
  subsection  (b),  the  period  of  effectiveness of a filing made in the
  jurisdiction in which the seller  is  located  is  governed  by  Section
  9--316(a) and (b).
    (d) Buyer  in  ordinary  course of business at wellhead or minehead. A
  buyer in ordinary course of business buying oil, gas, or other  minerals
  at  the  wellhead  or  minehead  or  after  extraction  takes free of an
  interest arising out of an encumbrance.
    (e) Possessory security interest not affected. Subsections (a) and (b)
  do not affect a security interest in goods  in  the  possession  of  the
  secured party under Section 9--313.