Safety syringe with retractable standard needle

• US 5,899,887 A
• Filed: 06/03/1998
• Issued: 05/04/1999
• Est. Priority Date: 12/26/1997
• Status: Expired due to Fees

• Current Assignee: Life-Shield Products, Inc.
• Original Assignee: Wen-Neng Liu
• Inventors: Liu, Wen-Neng
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US09/089,259
• Time in Patent Office: 335 Days
• Field of Search: 604/195, 604/110, 604/187, 604/263, 604/218, 128/919
• US Class Current: 604/195
• CPC Class Codes: A61M 2005/31506 formed as a single piece, e.g. moulded
• CPC Class Codes: A61M 2005/3224 Means to disalign the needle tip and syringe nozzle
• CPC Class Codes: A61M 2005/323 Connection between plunger distal end and needle hub proximal end, e.g. stud protruding from the plunger
• CPC Class Codes: A61M 2005/3231 Proximal end of needle captured or embedded inside piston head, e.g. by friction or hooks
• CPC Class Codes: A61M 5/322 Retractable needles, i.e. disconnected from and withdrawn into the syringe barrel by the piston devices for protecting guide needles in combination with catheters A61M25/0612
• CPC Class Codes: A61M 5/347 rotatable, e.g. bayonet or screw A61M5/344 takes precedence

Abstract

A safety syringe with retratable standard needle, including a syringe barrel, a plunger and an injection needle. A commonly used standard needle holder is replaceably connected with a second needle holder, whereby a user can conveniently replace the injection needle with another type of injection needle as necessary. A first needle pulling member is formed on the needle holder or the plunger, having at least one rotatable click. A second needle pulling member is formed on the plunger or the needle holder, having a detent. When the piston of the plunger is pushed to the bottom, the detent is easily and firmly engaged and hooked with the click. Thereafter, the injection needle and the needle holder can be together pulled into the barrel so as to ensure that the injection needle will not impale medical personnel or other persons.

Claims

1. A safety syringe with retratable standard needle, comprising:

(A) a syringe barrel having a first end and a second end, the syringe barrel being formed with an internal barrel chamber, the first end of the barrel being disposed with a needle socket defining a needle holder cavity, an annular shoulder section being formed between the barrel chamber and the needle holder cavity;

(B) a plunger having a first and a second ends, the first end being disposed with a piston and fitted into the barrel, the plunger having a first axis;

(C) a first needle holder having a first and a second ends, the second end of the first needle holder having a first fitting section;

(D) an injection needle inserted into the first end of the first needle holder;

(E) a second needle holder having a first end, a second end, a second fitting section and a plug section, the second fitting section being disposed at the first end and detachably connected with the first fitting section of the first needle holder, the plug section being disposed at the second end and fitted in the needle holder cavity of the needle socket, the second needle holder having a second axis, the second needle holder being formed with a through hole coaxial with the second axis for guiding a liquid medicine to flow through the through hole toward the injection needle or flow from the injection needle through the through hole into the barrel; and

(F) a needle pulling mechanism including;

(a) a first needle pulling member having a first end and a second end, the first end being integrally connected with one of the first end of the plunger and the second end of the second needle holder, the first needle pulling member having at least one click each having a first end and a second end, the first end being rotatably connected with the second end of the first needle pulling member, a distance between the first end of the click and either of the first axis and second axis being defined as a first distance, the second end of the click extending to the first end of the first needle pulling member, a distance between the second end of the click in a free state and either of the first axis and second axis being defined as a second distance which is less than the first distance, a distance between the second end of the click and the first end of the first needle pulling member being defined as a third distance, a distance between the first end of the click and the first end of the first needle pulling member being defined as a fourth distance which is larger than the third distance, whereby the click is formed as a ratchet; and

(b) a second needle pulling member having a first end and a second ends, the first end being connected with the other of the first end of the plunger and the second end of the second needle holder, the first end of the second needle pulling member being formed as a stem and the second end of the second needle pulling member being formed as a detent having a hook section, the hook section being formed with a radially extending hook face, when the first end of the plunger is pushed to the first end of the barrel, the hook section of the detent stretching open and sliding over the second end of the click, when the plunger is pulled from the first end of the barrel to the second end thereof, the hook face of the hook section of the detent abutting against the second end of the click with the stem tightly clamped by the second end of the click, whereby the first needle holder, the second needle holder and the injection needle can be together pulled into the barrel.

2. A safety syringe as claimed in claim 1, further comprising at least two radially arranged clicks.

3. A safety syringe as claimed in claim 1, wherein the first needle holder is a commonly used standard needle holder and the first fitting section thereof is formed with a truncated conic cavity.

4. A safety syringe as claimed in claim 3, wherein the second fitting section is formed as a truncated cone for detachably fitting into the truncated conic cavity of the first fitting section.

5. A safety syringe as claimed in claim 1, further comprising a leakproof structure including at least one sealing ring integrally formed on one of the wall of the needle holder cavity and the outer wall of the plug section of the second needle holder, the sealing ring sealedly contacting with the other of the wall of the needle holder cavity and the outer wall of the plug section of the second needle holder.

6. A safety syringe as claimed in claim 1, further comprising a leakproof structure including at least one first sealing ring and at least one second sealing ring, the first sealing ring being integrally formed on one of the wall of the needle holder cavity and the outer wall of the plug section of the second needle holder, the first sealing ring sealedly contacting with the other of the wall of the needle holder cavity and the outer wall of the plug section of the second needle holder, the second sealing ring being integrally formed on the other of the wall of the needle holder cavity and the outer wall of the plug section of the second needle holder, the second sealing ring sealedly contacting with said one of the wall of the needle holder cavity and the outer wall of the plug section of the second needle holder.

7. A safety syringe as claimed in claim 6, wherein one of the first and second sealing rings is adjacent to the other of the first and second sealing rings.