Abstract: A dosage unit for dosing a number of measured quantities of a liquid, such as insulin, from a cartridge (2), said dosage unit comprising a cylindrical casing (1) for the cartridge (2), the distal end of the casing (1) being provided with means for fastening an injection needle (5) with two points protruding at opposite sides, one point (7) thereof being provided to be plunged into the cartridge (2). The other end of the casing comprises a piston rod (13) for exerting a force on a piston (8) inside the cartridge (2) and an adjustment means (20) provided with an inner thread (21), said adjustment means being in rotatable engagement with an outer thread (19) on the outside of the casing (1). The adjustment means (20) is adapted to limit the length of the stroke of the piston rod (13) after adjustment in accordance with a measuring scale (37, 38) stating the desired dosage quantity.

Abstract: A disposable syringe includes first and second housing elements which are coupled together for rotation without axial movement therebetween. The first housing element receives a cartridge of a solution to be injected, and mounts a liquid outlet needle at its front end. A piston rod is disposed in the second housing element to move axially therein, and this piston rod includes a rod element and a nut element. The rod element is coupled to the first housing element to move axially therein without relative rotation therewith, and the nut element is threaded to the rod element for telescoping movement therewith and is configured to move axially in the second housing element without relative rotation therein. A pressure receiving element is mounted on the nut element.