# US 9,517,309 B2 · Control of plunger position in an injection device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,309 B2 - Document ID: US9517309B2 - Status: Granted - Kind: B2 - Application number: 14/903,981 - Filed: 2014-07-02 - Published: 2016-06-02 - Granted: 2016-12-13 - Earliest claimed: 2013-07-10 - Assignees: Owen Mumford Limited - Applicants: Owen Mumford Ltd - Inventors: Jerry Marshall; Jakub Tomaszewski - Web page: https://patentgrep.com/patent/US9517309B2 ## CPC - A61M 5/31536: {Blocking means to immobilize a selected dose, e.g. to administer equal doses} - A61M 5/20: Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically (A61M5/142 takes precedence) - A61M 5/31551: {including axial movement of dose setting member} - A61M 5/31553: {without axial movement of dose setting member} - A61M 5/31583: {the piston rod being moved by the rotational movement of a component directly in contact with it} - A61M 5/31593: {Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir} - A61M 2005/31508: {provided on the piston-rod} - A61M 2005/31516: {reducing dead-space in the syringe barrel after delivery} - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract An injection device includes a housing, a receptacle for receiving a medicine cartridge and configured for attachment to a proximal end of the housing, and a leadscrew having an end for engaging with a bung of a cartridge. The leadscrew has a first thread extending axially along an outer surface thereof and at least one axially extending guide track. The injection device includes a rotatable drive mechanism for engaging with the first thread or guide track, and a guiding element for engaging with the other of the first thread or guide track, the guiding element being non-rotatable with respect to the housing during an injection operation, whereby rotation of the drive mechanism causes the leadscrew to move axially in a proximal direction in order to deliver a dose from the cartridge. The injection device further includes a stop member located proximal to the rotatable drive mechanism and the guiding element. ## Claims ### Claim 1 An injection device comprising: a housing; a receptacle for receiving a medicine cartridge and configured for attachment to a proximal end of the housing; a leadscrew having an end for engaging with a bung of a cartridge, the leadscrew having a first thread extending axially along an outer surface thereof and having at least one axially extending guide track; a rotatable drive mechanism for engaging with said first thread or said guide track and a guiding element for engaging with the other of said first thread or said guide track, the guiding element being non-rotatable with respect to the housing at least during an injection operation, whereby rotation of the drive mechanism causes said leadscrew to move axially in a proximal direction in order to deliver a dose from the cartridge; and a stop member located proximal to said rotatable drive mechanism and said guiding element and being engaged with the or each guide track of said leadscrew to allow relative axial movement of the leadscrew and the stop member while causing the two components to rotate together, said stop member and a profile of the or each guide track being configured to define an end stop for the leadscrew in the proximal direction. ### Claim 2 (depends on 1) An injection device according to claim 1, wherein said profile comprises a step change in the depth of the or each guide track at an intermediate position, the or each guide track having a first depth x in a proximal region of the leadscrew and a second depth y in a distal region, where x is greater than y. ### Claim 3 (depends on 1) An injection device according to claim 1, wherein the stop member comprises at least one stop spline, the or each stop spline being configured to engage with the or each guide track. ### Claim 4 (depends on 2) An injection device according to claim 2, wherein the or each stop spline of the stop member extends a distance greater than y into the or each guide track. ### Claim 5 (depends on 1) An injection device according to claim 1, wherein the rotatable drive mechanism comprises a drive gear having a second thread provided on an inner surface thereof, the leadscrew and the drive gear being rotatably coupled by means of said first and second threads, and said guiding element is a locking bush located proximal to said drive gear and comprising one or more splines for engaging with the or each guide track of the leadscrew to allow relative axial movement of the leadscrew and the locking bush while preventing relative rotational movement, the locking bush being configured to allow rotation of the leadscrew when the receptacle is disconnected from the housing and to prevent rotation when the receptacle is connected to the housing. ### Claim 6 (depends on 2) An injection device according to claim 2, wherein the or each spline of the locking bush extends a distance less than y into the or each guide track. ### Claim 7 (depends on 5) An injection device according to claim 5 and further comprising a cartridge compression cup slidably mounted within the housing and being engagable by the receptacle during attachment of the receptacle to move said locking bush from a position in which it is rotatable with respect to the housing to a position in which it is non-rotatable, and wherein said stop member is located within said compression cup. ### Claim 8 (depends on 1) An injection device according to claim 1, wherein the rotatable drive mechanism comprises a drive collar comprising one or more splines for engaging with the or each guide track such that the drive collar and leadscrew rotate together, and the guiding element is a nut, said nut having a second thread on an inner surface thereof and the leadscrew and the nut being rotatably coupled by means of said first and second threads. ### Claim 9 (depends on 8) An injection device according to claim 8 and further comprising a cartridge compression cup slidably mounted within the housing and being engagable by the receptacle during attachment of the receptacle to move said nut from a position in which the nut is rotatable with respect to the housing to a position in which the nut is non-rotatable, and wherein said stop member is located within said compression cup. ### Claim 10 (depends on 9) An injection device according to claim 9, wherein said stop member is rotatable within said compression cup. ### Claim 11 (depends on 2) An injection device according to claim 2, wherein the or each drive spline of the drive collar extends a distance less than y into the or each guide track. ### Claim 12 (depends on 1) An injection device according to claim 1, wherein a proximal end position of the stop member is defined by abutment of the stop member with an attached cartridge. ### Claim 13 (depends on 1) An injection device according to claim 1, further comprising a torsion spring coupled to said rotatable drive mechanism in order to rotate the drive mechanism within the housing. ### Claim 14 (depends on 1) An injection device according to claim 1, wherein said stop member is a stop collar. ### Claim 15 An injection device comprising: a housing; a receptacle for receiving a medicine cartridge and configured for attachment to a proximal end of the housing; a leadscrew having an end for engaging with a bung of a cartridge, the leadscrew having a first thread extending axially along an outer surface thereof and having at least one axially extending guide track; a drive gear having a second thread on an inner surface thereof, the leadscrew and the drive gear being rotatably coupled by means of said first and second threads; a drive mechanism for causing relative rotation of said leadscrew and said drive gear in order to deliver a dose from the cartridge; a locking bush located proximal to said drive gear and being engaged with the or each guide track of the leadscrew to allow relative axial movement of the leadscrew and the locking bush while preventing relative rotational movement, the locking bush being configured to allow rotation of the leadscrew when the receptacle is disconnected from the housing and to prevent rotation when the receptacle is connected to the housing; and a stop member located proximal to said locking bush and being engaged with the or each guide track of said leadscrew to allow relative axial movement of the leadscrew and the stop member while allowing the two components to rotate together, said stop collar and a profile of the or each guide track being configured to define an end stop for the leadscrew in the proximal direction.