US Patent 8062268 Injector with thumb operable scroll wheel

The present invention relates to an injector comprising a housing (10); a medicament container (12) disposed within the housing, wherein the container has at least one chamber, a front opening with or for an injection needle for delivering the medicament therethrough, and at least one movable stopper; a drive unit (22) slidable arranged within the housing, and capable of acting on said container for expelling medicament through said needle; and a scroll wheel member (24) operatively connected to said housing via a transmission and wherein said scroll wheel member comprises friction enhancing means such that it is capable of being maneuverable with a finger of a user for performing a function.