# US 8,784,374 B2 · Disposable self-destructive syringe > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,374 B2 - Document ID: US8784374B2 - Status: Granted - Kind: B2 - Application number: 11/571,828 - Filed: 2006-04-05 - Published: 2009-10-22 - Granted: 2014-07-22 - Earliest claimed: 2005-04-05 - Applicants: Zhong Feng - Inventors: Zhong Feng - Web page: https://patentgrep.com/patent/US8784374B2 ## 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 2005/5026: {allowing single filling of syringe} - A61M 2005/5033: {by use of an intermediate blocking member positioned between the syringe barrel and the piston rod to prevent retraction of the latter, e.g. toothed clip placed 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 The present invention discloses a disposable self-destructive syringe, which belongs to syringes for medical treatment, comprises a needle (1), a tube (2), a injecting piston-rod (3), ratchet grooves (4), a restrictive step (5), an installation opening (6), an anti-return member (7), anti-return prods (8), ratchets (9), a sealing plug (10) and a reciprocal motion region (11). The needle is conglutinated on the tube, the injecting piston-rod is arranged in the tube, the anti-return member is arranged in the gap of the injecting piston-rod and in the rear end of the tube, and the sealing plug is arranged in the tube and mounted on the front end of the injecting piston-rod. The syringe is convenient to discharge the inhaled air as sucking medical liquid, begins to be self-destructive after sucking for predetermined amount and can not suck medical liquid again during and after injecting. Furthermore, the ratchet grooves arranged on the injecting piston-rod can be one or more, which the fewer the number of ratchet grooves, the larger the interval of discharging inhaled air will become. The disposable self-destructive syringe according to the invention of which dose is precise is convenient to operate and will be self-destructive once used. ## Claims ### Claim 1 A disposable self-destructive syringe, comprising: a cylinder, having a flat tubular inwall, bonding with an injecting needle; a sealing plug disposed in said cylinder to slide along said inwall thereof in a sealed manner; a one piece integrated injecting piston-rod having a front end coupling with said sealing plug to move said sealing plug within said cylinder, wherein said injecting piston-rod has a center gap defining a center ratchet groove at a front portion of said injecting piston-rod and a reciprocal motion region at a rear portion of said injecting piston-rod; and an anti-return member slidably coupling with said injecting piston-rod in unidirectional manner, wherein when said injecting piston-rod is pulled backward for sucking liquid into said cylinder, said anti-return member is retained along said reciprocal motion region of said center gap for enabling said injecting piston-rod being reciprocally moved for expelling inhaled air out of said cylinder, wherein when said injecting piston-rod is pushed backward to move said anti-return member from said reciprocal motion region of said center gap to said ratchet groove, said anti-return member fixes at said injecting piston-rod along said ratchet groove, wherein when said injecting piston-rod is pushed forward during injection process, said injecting piston-rod and said anti-return member are moved at the same time, wherein said anti-return member pierces into said inwall of said cylinder, such that after said injection process is completed, said anti-return member is affixed in said cylinder to prevent said injecting piston-rod being pulled back in said cylinder. ### Claim 2 (depends on 1) The disposable self-destructive syringe, as recited in claim 1, wherein said injecting piston-rod further comprises a restrictive step formed at said center gap to define said reciprocal motion region between said ratchet groove and said restrictive step, such that when said anti-return member is moved across said restrictive step to said reciprocal motion region, said anti-return member is prohibited to move back to out of said reciprocal motion region. ### Claim 3 (depends on 1) The disposable self-destructive syringe, as recited in claim 1, wherein said injecting piston-rod further comprises one or more ratchets spacedly formed along said ratchet groove to engage with said anti-return member so as to fix said anti-return member at said ratchet groove. ### Claim 4 (depends on 2) The disposable self-destructive syringe, as recited in claim 2, wherein said injecting piston-rod further comprises one or more ratchets spacedly formed along said ratchet groove to engage with said anti-return member so as to fix said anti-return member at said ratchet groove. ### Claim 5 (depends on 1) The disposable self-destructive syringe, as recited in claim 1, wherein said anti-return member comprises two anti-return prods extending from two outer side of said anti-return member to pierce into said inwall of said cylinder in unidirectional manner. ### Claim 6 (depends on 4) The disposable self-destructive syringe, as recited in claim 4, wherein said anti-return member comprises two anti-return prods extending from two outer side of said anti-return member to pierce into said inwall of said cylinder in unidirectional manner. ### Claim 7 (depends on 5) The disposable self-destructive syringe, as recited in claim 5, wherein said anti-return member is made of spring steel sheet. ### Claim 8 (depends on 6) The disposable self-destructive syringe, as recited in claim 6, wherein said anti-return member is made of spring steel sheet. ### Claim 9 (depends on 2) The disposable self-destructive syringe, as recited in claim 2, wherein said injecting piston-rod further comprises an installation opening provided at a rear end of said center gap of said injecting piston-rod at a position behind said restrictive step, such that when said anti-return member passes said restrictive step from said installation opening to said reciprocal motion region, said anti-return member is prohibited to move back to out of said installation opening. ### Claim 10 (depends on 8) The disposable self-destructive syringe, as recited in claim 8, wherein said injecting piston-rod further comprises an installation opening provided at a rear end of said center gap of said injecting piston-rod at a position behind said restrictive step, such that when said anti-return member passes said restrictive step from said installation opening to said reciprocal motion region, said anti-return member is prohibited to move back to out of said installation opening. ### Claim 11 A method of injecting liquid by a disposable self-destructive syringe which comprises a cylinder, having a flat tubular inwall, bonding with an injecting needle, a sealing plug disposed in said cylinder to slide along said inwall thereof in a sealed manner, an injecting piston-rod having a front end coupling with said sealing plug to move said sealing plug within said cylinder, and an anti-return member coupling with said injecting piston-rod, wherein the method comprises the steps of: (a) pulling said injecting piston-rod backward for sucking liquid into said cylinder, wherein said injecting piston-rod has a center gap defining at least a center ratchet groove at a front portion of said injecting piston-rod and a reciprocal motion region at a rear portion of said injecting piston-rod; (b) when said anti-return member is retained along said reciprocal motion region of said center gap of said injecting piston-rod, enabling said injecting piston-rod being reciprocally moved for expelling inhaled air out of said cylinder; (c) pushing said injecting piston-rod backward to move said anti-return member from said reciprocal motion region of said center gap to said ratchet groove; and (d) pushing said injecting piston-rod and said anti-return member forward at the same time for discharging said liquid out of said cylinder via said sealing plug, wherein said anti-return member fixes at said injecting piston-rod along said ratchet groove and pierces into said inwall of said cylinder to prevent said injecting piston-rod being pulled back in said cylinder after said liquid is discharged, so as to self-destruct said disposable self-destructive syringe once being used. ### Claim 12 (depends on 11) The method as recited in claim 11 wherein, in the step (a), said anti-return member is retained along said reciprocal motion region when said injecting piston-rod is pulled backward. ### Claim 13 (depends on 11) The method, as recited in claim 11, wherein the step (c) further comprises a step of engaging said anti-return member with one or more ratchets spacedly formed along said ratchet groove to fix said anti-return member at said ratchet groove. ### Claim 14 (depends on 12) The method, as recited in claim 12, wherein the step (c) further comprises a step of engaging said anti-return member with one or more ratchets spacedly formed along said ratchet groove to fix said anti-return member at said ratchet groove. ### Claim 15 (depends on 11) The method, as recited in claim 11, wherein the step (b) further comprises a step of providing a restrictive step at said center gap to define said reciprocal motion region between said ratchet groove and said restrictive step, wherein when said anti-return member is moved across said restrictive step to said reciprocal motion region, said anti-return member is prohibited to move back to out of said reciprocal motion region. ### Claim 16 (depends on 14) The method, as recited in claim 14, wherein the step (b) further comprises a step of providing a restrictive step at said center gap to define said reciprocal motion region between said ratchet groove and said restrictive step, wherein when said anti-return member is moved across said restrictive step to said reciprocal motion region, said anti-return member is prohibited to move back to out of said reciprocal motion region. ### Claim 17 (depends on 11) The method, as recited in claim 11, wherein said anti-return member comprises two anti-return prods extending from two outer side of said anti-return member to pierce into said inwall of said cylinder in unidirectional manner. ### Claim 18 (depends on 16) The method, as recited in claim 16, wherein said anti-return member comprises two anti-return prods extending from two outer side of said anti-return member to pierce into said inwall of said cylinder in unidirectional manner. ### Claim 19 (depends on 16) The method, as recited in claim 16, before the step (a), further comprising a step of passing said anti-return member through said restrictive step from an installation opening to said reciprocal motion region, wherein said installation opening is provided at a rear end of said center gap of said injecting piston-rod at a position behind said restrictive step, such that when said anti-return member passes said restrictive step from said installation opening to said reciprocal motion region, said anti-return member is prohibited to move back to out of said installation opening. ### Claim 20 (depends on 18) The method, as recited in claim 18, before the step (a), further comprising a step of passing said anti-return member through said restrictive step from an installation opening to said reciprocal motion region, wherein said installation opening is provided at a rear end of said center gap of said injecting piston-rod at a position behind said restrictive step, such that when said anti-return member passes said restrictive step from said installation opening to said reciprocal motion region, said anti-return member is prohibited to move back to out of said installation opening.