# US 8,540,670 B2 · Passive reuse prevention syringe that uses a retaining ring lock > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,540,670 B2 - Document ID: US8540670B2 - Status: Granted - Kind: B2 - Application number: 12/492,554 - Filed: 2009-06-26 - Published: 2009-12-31 - Granted: 2013-09-24 - Earliest claimed: 2008-06-26 - Assignees: Becton, Dickinson and Company - Applicants: Brian H. Wayman; Robert Odell; Richard James Caizza - Inventors: Brian H. Wayman; Robert Odell; Richard James Caizza - Web page: https://patentgrep.com/patent/US8540670B2 ## CPC - A61M 5/502: {for blocking the piston} - A61M 5/5013: {Means for blocking the piston or the fluid passageway to prevent illegal refilling of a syringe} - A61M 5/5066: {Means for preventing re-use by disconnection of piston and piston-rod} - A61M 2005/5073: {by breaking or rupturing the connection parts} - 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 assembly includes a syringe barrel having an inside surface defining a chamber and an outlet. A plunger assembly is disposed within the syringe barrel and includes an elongate plunger rod having a distal end surface, a plunger head having a distal sealing surface and a proximal end surface having a continuous perimeter, and a breakable neck portion integrally connecting the plunger rod and the plunger head. A retaining ring lock is disposed on the inside surface of the barrel and defines an engagement surface about a perimeter of the chamber. The retaining ring lock is adapted to engage and retain the plunger head in a locked position within the chamber. The engagement surface of the retaining ring lock engages the continuous perimeter of the proximal end surface of the plunger head in a perimetrical engagement when the plunger head is in the locked position. ## Claims ### Claim 1 A syringe assembly, comprising: a syringe barrel having an inside surface defining a chamber, an open proximal end, a distal end, and an outlet disposed adjacent the distal end in fluid communication with the chamber; a plunger assembly disposed at least partially within the syringe barrel, comprising an elongate plunger rod and a plunger head having a distal sealing surface and a proximal end surface, the proximal end surface of the plunger head having a continuous perimeter and the plunger rod and the plunger head being integrally connected; and a retaining ring lock disposed on the inside surface of the barrel and extending into the chamber of the barrel and defining an engagement surface about a perimeter of the chamber of the barrel, the retaining ring lock adapted to engage and retain the plunger head in a locked position at least partially within the chamber of the barrel, wherein the engagement surface of the retaining ring lock engages the continuous perimeter of the proximal end surface of the plunger head in a perimetrical engagement when the plunger head is in the locked position, and wherein the plunger assembly is formed as a single, monolithic piece. ### Claim 2 (depends on 1) The syringe assembly according to claim 1, wherein the plunger head has a width slightly greater than a width of the chamber of the barrel at the distal sealing surface. ### Claim 3 (depends on 1) The syringe assembly according to claim 1, wherein the engagement surface of the retaining ring lock is continuous about the perimeter of the chamber of the barrel and the retaining ring lock engages the continuous perimeter of the proximal end surface of the plunger head in a continuous perimetrical engagement when the plunger head is in the locked position. ### Claim 4 (depends on 1) The syringe assembly according to claim 1, wherein the retaining ring lock is disposed within the chamber of the barrel adjacent the distal end of the barrel. ### Claim 5 (depends on 4) The syringe assembly according to claim 4, wherein the retaining ring lock retains the plunger head in the locked position within the chamber of the barrel adjacent the distal end of the barrel. ### Claim 6 (depends on 1) The syringe assembly according to claim 1, further comprising a needle cannula in fluid communication with the chamber of the barrel. ### Claim 7 (depends on 1) The syringe assembly according to claim 1, wherein the plunger assembly further includes a breakable neck portion extending between the plunger rod and the proximal end surface of the plunger head, the plunger rod and the plunger head being integrally connected by the breakable neck portion. ### Claim 8 (depends on 7) The syringe assembly according to claim 7, wherein the breakable neck portion comprises a tapered portion. ### Claim 9 (depends on 8) The syringe assembly according to claim 8, wherein the breakable neck portion has a center disposed between the proximal end surface of the plunger head and the distal end surface of the plunger rod, and tapers from both the proximal end surface of the plunger head and the distal end surface of the plunger rod so as to have a reduced diameter at the center. ### Claim 10 (depends on 7) The syringe assembly according to claim 7, wherein the breakable neck portion is adapted to break upon application of a force to the plunger rod that is greater than a force necessary to at least partially aspirate the syringe, and less than a force necessary to withdraw the plunger head past the retaining ring lock. ### Claim 11 (depends on 1) The syringe assembly according to claim 1, wherein the retaining ring lock is integral with the inside surface of the barrel. ### Claim 12 (depends on 11) The syringe assembly according to claim 11, wherein the retaining ring lock has a substantially V-shaped cross-section, a proximal beveled surface of the retaining ring lock engages the distal sealing surface of the plunger head such that the plunger head is slidable past the retaining ring lock in a distal direction, and the engagement surface of the retaining ring lock is a distal beveled surface of the retaining ring lock that engages the proximal end surface of the plunger head such that the plunger head is restrained from sliding past the retaining ring lock in a proximal direction. ### Claim 13 (depends on 11) The syringe assembly according to claim 11, wherein the retaining ring lock has a substantially V-shaped cross-section with a rounded apex, a proximal surface of the retaining ring lock that engages the distal sealing surface of the plunger head such that the plunger head is slidable past the retaining ring lock in a distal direction, and the engagement surface of the retaining ring lock is a distal surface of the retaining ring lock that engages the proximal end surface of the plunger head such that the plunger head is restrained from sliding past the retaining ring lock in a proximal direction. ### Claim 14 (depends on 11) The syringe assembly according to claim 11, wherein the retaining ring lock has a substantially V-shaped cross-section with a flat apex, a curved proximal surface of the retaining ring lock that engages the distal sealing surface of the plunger head such that the plunger head is slidable past the retaining ring lock in a distal direction, and the engagement surface of the retaining ring lock is a curved distal surface of the retaining ring lock that engages the proximal end surface of the plunger head such that the plunger head is restrained from sliding past the retaining ring lock in a proximal direction. ### Claim 15 A plunger assembly for a syringe, the plunger assembly comprising: an elongate plunger rod; a plunger head having a distal sealing surface and a proximal end surface, the proximal end surface of the plunger head having a continuous perimeter adapted to provide a perimetrical engagement with a chamber of a syringe barrel; and a breakable neck portion extending between the plunger rod and the proximal end surface of the plunger head, wherein the plunger rod and the plunger head are integrally connected by the breakable neck portion, wherein the plunger assembly is formed as a single, monolithic piece, and wherein the breakable neck portion comprises a center disposed between the proximal end surface of the plunger head and the distal end surface of the plunger rod and tapered portions extend from both the proximal end surface of the plunger head and the plunger rod so as to have a reduced diameter at the center. ### Claim 16 (depends on 15) The plunger assembly according to claim 15, wherein the plunger head is adapted to engage a retaining ring lock disposed within a barrel of the syringe such that the plunger head is capable of being retained in a locked position at least partially within the barrel of the syringe. ### Claim 17 (depends on 16) The plunger assembly according to claim 16, wherein the breakable neck portion is adapted to break upon application of a force to the plunger rod that is greater than a force necessary to at least partially aspirate the syringe, and less than a force necessary to withdraw the plunger head past the retaining ring lock. ### Claim 18 (depends on 15) The plunger assembly according to claim 15, wherein the plunger head has a width at the distal sealing surface greater than a width of the plunger head at the proximal end surface.