Mixing syringe having a rotationally restrained piston rod

Claim 1

A syringe device for separately storing and facilitating mixing of two substances preparatory to discharge from the syringe, comprising, in combination, body means defining a longitudinally extending chamber having an open end and a discharge end, plunger means disposed within said chamber and longitudinally movable therein, said body means having a first pair of ribs formed within said chamber and extending from within said chamber and extending from adjacent said discharge end longitudinally along said chamber a distance substantially less than the longitudinal length of said chamber, said body means having a second pair of ribs formed within said chamber and extending from adjAcent said open end longitudinally along said chamber to a position spaced longitudinally from said first pair of ribs to define an intermediate generally cylindrical chamber portion, first piston means supported by said plunger means for movement between a position engaging said first pair of ribs and a position disposed within said intermediate chamber portion, said first piston means having a peripheral surface configuration conforming to the cross-sectional configuration of said chamber taken through said first pair of ribs so as to provide a sealing relation with the peripheral surface of said chamber when said first piston means is engaging said first pair of ribs, said first piston means when in engagement with said first pair of ribs defining with said discharge end a first compartment to receive one of said two substances, second piston means carried by said plunger means in longitudinally spaced relation from said first piston means and having a peripheral surface configuration conforming to the cross-sectional configuration of said chamber taken through said second pair of ribs so as to engage said second pair of ribs and the adjacent peripheral surface of said chamber in sealing relation therewith, said second piston means cooperating with said first piston means to define a second compartment therebetween adapted to receive the other of said two substances, said second piston means and said second pair of ribs cooperating to prevent rotation of said plunger means about its longitudinal axis while allowing movement of said plunger means to a position wherein said first piston means is spaced longitudinally from said first pair of ribs to allow intermixing of said substances, said plunger means being thereafter movable to effect discharge of the mixed substances from said discharge end of said body means.