# US 9,872,960 B2 · Dose divider syringe > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,872,960 B2 - Document ID: US9872960B2 - Status: Granted - Kind: B2 - Application number: 14/563,106 - Filed: 2014-12-08 - Published: 2016-01-28 - Granted: 2018-01-23 - Earliest claimed: 2014-07-24 - Assignees: Teleflex Medical Incorporated - Applicants: Teleflex Medical Incorporated - Inventors: Huy Tran; Perry Croll - Web page: https://patentgrep.com/patent/US9872960B2 ## CPC - A61M 5/31511: {Piston or piston-rod constructions, e.g. connection of piston with piston-rod (A61M5/5066 takes precedence)} - A61M 5/31595: {Pre-defined multi-dose administration by repeated overcoming of means blocking the free advancing movement of piston rod, e.g. by tearing or de-blocking} - A61M 5/31573: {Accuracy improving means} - A61M 2005/31508: {provided on the piston-rod} - 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 A syringe includes a barrel having an internal surface defining an internal bore therein, and a plunger disposed within the internal bore of the barrel. A distal end of the plunger is inserted into a proximal end of the barrel. At least one radial projection is disposed on an external surface of the plunger, the at least one radial projection includes a proximal ramp and a distal ramp. The distal ramp includes a first point being a point of incipient contact with the internal surface of the barrel, and the at least one radial projection has a first slope relative to the longitudinal axis at the first point. The at least one radial projection has a second slope at a second point along the proximal ramp. An absolute value of the first slope is different from an absolute value of the second slope. ## Claims ### Claim 1 A syringe, comprising: a barrel having an internal surface defining an internal bore therein; a plunger disposed within the internal bore of the barrel, a distal end of the plunger being inserted into a proximal end of the barrel, a proximal end of the plunger being opposite the distal end of the plunger along a longitudinal axis of the plunger; and at least one radial projection disposed on an external surface of the plunger, the at least one radial projection including a proximal ramp and a distal ramp, the proximal ramp being disposed on a proximal side of the at least one radial projection, and the distal ramp being disposed on a distal side of the at least one radial projection, the distal ramp having a first maximum radial height from the longitudinal axis, and the proximal ramp having a second maximum radial height from the longitudinal axis, the distal ramp including a leading point of incipient contact with the internal surface of the barrel, the first leading point of incipient contact being located at a first radial distance from the longitudinal axis, the at least one radial projection having a first slope relative to the longitudinal axis at the leading point of incipient contact, the at least one radial projection having a second slope at a trailing point of contact with the internal surface of the barrel along the proximal ramp located a second radial distance from the from the longitudinal axis, the second radial distance being substantially equal to the first radial distance, and an absolute value of the first slope being different from an absolute value of the second slope, wherein the first slope at the leading point of incipient contact on the distal ramp is a continuous slope, and wherein the first radial distance of the leading point of incipient contact on the distal ramp is less than a maximum radial height of the distal ramp, and wherein the second slope at the trailing point of contact on the proximal ramp is a continuous slope, and wherein the second radial distance of the trailing point of contact on the proximal ramp is less than a maximum radial height of the proximal ramp. ### Claim 2 (depends on 1) The syringe according to claim 1, wherein the internal bore of the barrel includes an undercut near a proximal end of the barrel, the undercut defining a minimum inscribed diameter of the internal bore, and a maximum circumscribed diameter of the plunger at the at least one radial projection is greater than the minimum inscribed diameter of the internal bore. ### Claim 3 (depends on 1) The syringe according to claim 1, wherein the at least one radial projection consists of a plurality of radial projections. ### Claim 4 (depends on 1) The syringe according to claim 1, wherein the at least one radial projection includes at least two radial projections located at substantially identical axial locations along the longitudinal axis. ### Claim 5 (depends on 1) The syringe according to claim 1, wherein the at least one radial projection includes at least two radial projections located at substantially identical circumferential locations about the plunger. ### Claim 6 (depends on 1) The syringe according to claim 1, wherein the absolute value of the first slope is greater than the absolute value of the second slope. ### Claim 7 (depends on 1) The syringe according to claim 1, wherein the first slope is perpendicular to the longitudinal axis. ### Claim 8 (depends on 1) The syringe according to claim 1, wherein the second slope is not perpendicular to the longitudinal axis. ### Claim 9 (depends on 1) The syringe according to claim 1, wherein the proximal ramp includes a first substantially linear ramp. ### Claim 10 (depends on 9) The syringe according to claim 9, wherein the distal ramp includes a second substantially linear ramp. ### Claim 11 (depends on 9) The syringe according to claim 9, wherein the distal ramp includes a convex ramp. ### Claim 12 (depends on 9) The syringe according to claim 9, wherein the distal ramp includes a concave ramp. ### Claim 13 (depends on 1) The syringe according to claim 1, wherein the proximal ramp includes a first convex ramp. ### Claim 14 (depends on 1) The syringe according to claim 1, wherein the proximal ramp includes a first concave ramp.