# US 8,784,376 B2 · Thumb press frangible feature for re-use prevention > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,376 B2 - Document ID: US8784376B2 - Status: Granted - Kind: B2 - Application number: 13/693,163 - Filed: 2012-12-04 - Published: 2014-06-05 - Granted: 2014-07-22 - Earliest claimed: 2012-12-04 - Assignees: Becton, Dickinson and Company - Applicants: Becton, Dickinson and Company - Inventors: Yan Yevmenenko; Andrew Wong - Web page: https://patentgrep.com/patent/US8784376B2 ## CPC - A61M 5/5066: {Means for preventing re-use by disconnection of piston and piston-rod} - A61M 5/502: {for blocking the piston} - 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 Syringe assemblies having a passive disabling system to prevent reuse are provided. According to one or more embodiments, the syringe assembly comprises a barrel, plunger rod and detachable thumb press wherein the plunger rod further comprises flexible locking petals that lock the plunger rod within the barrel and one or more frangible connection or break point at the proximal end of the plunger rod disposed either inside the thumb press or immediately adjacent to the thumb press to separate the thumb press from the main body of the plunger rod when a user applies sufficient proximal force to the plunger rod after it has been locked within the barrel. ## Claims ### Claim 1 A syringe assembly comprising: a barrel including a cylindrical sidewall having an interior surface with a first cross-sectional width defining a chamber for retaining fluid, an open proximal end and a distal end including a distal wall having an opening therethrough in fluid communication with said chamber; an elongate plunger rod including a proximal end with a detachable thumb press, a distal end, a main body extending between the proximal and distal end, and a frangible element disposed at the proximal end of the plunger rod inside the thumb press, the frangible element comprising a plurality of break point connections inside the thumb press, the plunger rod being distally and proximally movable within the chamber, the distal end including a stopper slidably positioned in fluid-tight engagement with the inside surface of the barrel for drawing fluid into and driving fluid out of the chamber by movement of the stopper relative to the barrel; and a locking element disposed on one or more of the barrel and plunger rod. ### Claim 2 (depends on 1) The syringe assembly of claim 1, wherein application of a continuous distally directed force to the plunger rod causes the stopper and plunger rod to move together in the distal direction within the barrel until the locking element locks the plunger rod in the barrel and a subsequent application of a proximally directed force to the plunger causes the frangible element of the plunger rod to break and separates the thumb press from the main body of the plunger rod to prevent reuse of the syringe assembly. ### Claim 3 (depends on 1) The syringe assembly of claim 1, wherein the one or more point connections are adapted to withstand application of a force on the plunger rod in the distal direction and break upon application of a force in the proximal direction after the locking element locks the plunger rod in the barrel. ### Claim 4 (depends on 1) The syringe assembly of claim 1, wherein the force required to move the plunger rod in a proximal direction after the locking element locks the plunger rod in the barrel exceeds the force required to break the one or more break point connections. ### Claim 5 (depends on 1) The syringe assembly of claim 1, wherein the frangible element comprises a knock-out tab disposed inside the thumb press and extending radially from the thumb press to the plunger rod body. ### Claim 6 (depends on 5) The syringe assembly of claim 5, wherein the knock-out tab includes four break points, each break point extending radially to removably attach the thumb press to the plunger rod body. ### Claim 7 (depends on 1) The syringe assembly of claim 1, wherein the locking element comprises a flexible locking petal between the thumb press and the main body. ### Claim 8 (depends on 7) The syringe assembly of claim 7, wherein the flexible locking petal includes four individual leaves disposed around the entire circumference of the plunger rod. ### Claim 9 (depends on 8) The syringe assembly of claim 8, wherein the individual leaves include a tapered outer edge. ### Claim 10 (depends on 7) The syringe assembly of claim 7, wherein the locking petal is permitted to advance distally past a locking element disposed in the sidewall of the barrel and lock the plunger rod in the barrel to prevent reuse of the syringe assembly. ### Claim 11 (depends on 1) The syringe assembly of claim 1, wherein the locking element is disposed on the barrel and comprises a second cross-sectional width that is less than a first cross-sectional width of the barrel. ### Claim 12 (depends on 1) The syringe assembly of claim 1, further comprising one or more spacer bumps disposed between the distal end of the thumb press and proximal end of the plunger rod. ### Claim 13 (depends on 1) The syringe assembly of claim 1, wherein the main body of plunger rod comprises two intersecting transverse members to form four quadrants. ### Claim 14 (depends on 13) The syringe assembly of claim 13, wherein one or more spacer bumps is disposed between the intersection of the thumb press and one or more of the four quadrants of the plunger rod. ### Claim 15 (depends on 1) The syringe assembly of claim 1, further including a spacer clip disposed at a perpendicular orientation to the frangible element. ### Claim 16 (depends on 1) The syringe assembly of claim 1, further including a spacer clip disposed between the thumb press and plunger rod. ### Claim 17 (depends on 16) The syringe assembly of claim 16, wherein the spacer clip comprises one or more anti-rotation bumps. ### Claim 18 (depends on 16) The syringe assembly of claim 16, wherein the spacer clip is formed from a wire. ### Claim 19 (depends on 18) The syringe assembly of claim 18, wherein the spacer clip comprises one or more retaining hooks. ### Claim 20 (depends on 19) The syringe assembly of claim 19, further including a step molded into the plunger rod to accommodate the spacer clip and register the retaining hooks of the spacer clip. ### Claim 21 (depends on 16) The syringe assembly of claim 16, wherein the spacer clip and frangible element are disposed at a distance from the thumb press. ### Claim 22 (depends on 1) The syringe assembly of claim 1, wherein the stopper is attached to a stopper-engaging portion of the plunger rod located on the distal end of the plunger rod. ### Claim 23 (depends on 1) The syringe assembly of claim 1, wherein the stopper is integrally connected to the distal end of the plunger rod. ### Claim 24 An elongate syringe plunger rod comprising: a proximal end including a detachable thumb press, a distal end including a stopper-engaging portion, a main body extending between the proximal and distal end, and a frangible element disposed at the proximal end of the plunger rod inside the thumb press, the frangible element comprising a plurality of break point connections inside the thumb press.