# US 5,346,475 A · Single use syringe

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- Number: US 5,346,475 A
- Document ID: US5346475A
- Status: Granted
- Kind: A
- Application number: 08/144,882
- Filed: 1993-10-27
- Granted: 1994-09-13
- Earliest claimed: 1993-10-27
- Inventors: Edward Gregorio
- Web page: https://patentgrep.com/patent/US5346475A

## CPC

- A61M 5/3271: {with guiding tracks for controlled sliding of needle protective sleeve from needle exposing to needle covering position}
- 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 single-use syringe for covering its needle after injection of a medical preparation. The syringe has a barrel and has a non-reversible shield for covering the needle. The shield has an inclined interior shield tooth of resilient material, and the barrel has a coacting inclined exterior row of teeth of non-resilient material, whereby the shield tooth locks behind a barrel tooth when the needle is covered and the shield cannot reverse its travel.

## Claims

### Claim 1

A single use syringe comprising:
a barrel having an axis and having an end needle and having a coaxial plunger;
a protective shield slidably engaging and supported on the barrel for covering the needle after needle use; and
a non-reversible lock unit for locking the shield in place to the barrel after covering the needle wherein the lock unit includes at least one lock subassembly comprising:
at least one axial parallel row of barrel teeth fixedly connected to the barrel at an outer surface of the barrel; and
at least one shield tooth fixedly connected to the shield at an interior surface thereof;
said shield tooth being a resilient spring-like tooth and being inclined in a rearward direction away from the needle for locking in front of a tooth at the front of the row of barrel teeth when the shield is in a needle-covering position, wherein
the shield has a slot disposed parallel to the axis for travel therethrough of the row of barrel teeth;
the shield has a bubble-like wall extension disposed over and covering over the slot; and
a bar is provided on the barrel to maintain the cover in a spaced relationship between the barrel and the cover.

### Claim 2 (depends on 1)

The syringe of claim 1, wherein a curved flange is affixed to the outer surface of the protective shield for gripping during use.

### Claim 3 (depends on 1)

The syringe of claim 1, wherein
the barrel has a stop member disposed near the front of the row of barrel teeth and peripherally spaced therefrom; and
the shield has a stop member disposed near the rear of the shield for hitting the barrel stop member and stopping travel of the shield after covering the needle.