A panel joint, including first and second upstanding metallic panel members, spacer members on the first panel member, a vertically slidable locking member on the second panel member, and cooperative slots in the second panel member and locking member which receive the spacer members in first positions...http://www.google.es/patents/US4266386?utm_source=gb-gplus-sharePatente US4266386 - Panel joint for assembling panel members
