Dry disposable nozzle assembly for medical jet injector

• US 5,062,830 A
• Filed: 04/04/1990
• Issued: 11/05/1991
• Est. Priority Date: 04/04/1990
• Status: Expired due to Fees

• Current Assignee: Medi-Ject Corporation
• Original Assignee: Dereta Limited
• Inventors: Dunlap, Kenneth W.
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Dawson, Glenn K.
• Application Number:
  US07/503,948
• Time in Patent Office: 580 Days
• Field of Search: 604/68, 604/69, 604/70, 604/71, 604/72, 604/275
• US Class Current: 604/68
• CPC Class Codes: A61M 2005/31516 reducing dead-space in the syringe barrel after delivery
• CPC Class Codes: A61M 5/30 Syringes for injection by jet action, without needle, e.g. for use with replaceable ampoules or carpules
• CPC Class Codes: A61M 5/31515 Connection of piston with piston rod

Abstract

A dry, disposable, low-cost nozzle assembly for a spring-powered medical injector power unit comprises a generally cylindrical molded plastic nozzle body which is removably attached to a medical injector module and it includes a longitudinal bore of a predetermined diameter and terminating in a conical segment short of the end surface thereof. A counterbore of a fine diameter is then formed between the apex and the end of the nozzle member, forming the ejector orifice. A seal member fits within the bore of the nozzle body and releasably attaches to the power unit'"'"'s plunger. The seal member includes a conical tip dimensioned to fit with close tolerance in the conical segment of the body portion of the nozzle.

Claims

1. A dry disposable nozzle assembly for a hypodermic jet injector of the type including a body containing a power spring operatively coupled to a ram member which is movable at high velocity between a cocked position and a released position, said body further including a plunger assembly disposed within a generally tubular metal sleeve in the path of travel of said ram to be driven thereby where the plunger assembly includes a radial groove, said nozzle assembly including in combination:

(a) a disposable molded plastic nozzle of a generally cylindrical shape adapted to be disposed within and at least partly reinforced on the exterior thereof by said tubular metal sleeve and having first and second ends with an axial bore of circular cross-section extending from said first end toward said second end, said axial bore terminating in a generally conical segment having an apex lying on a longitudinal axis of said axial bore and a counterbore of a predetermined, small diameter relative to said axial bore extending from said second end to said apex and forming a one-piece ejection orifice;

(b) means for removably attaching said molded plastic nozzle to said body within said metal sleeve; and

(c) a disposable seal member encompassed by said molded plastic nozzle and fitted into said axial bore for longitudinal motion therein and including an integrally formed generally conical head dimensioned to fit within said generally conical segment of said axial bore with a predetermined close tolerance, said seal member including a socket formed in said seal member, said socket including a detent adapted to cooperate with said radial groove in said plunger assembly for receiving and releasably locking said plunger assembly.

2. The dry disposable nozzle assembly as in claim 1 wherein said seal member includes at least one annular, outwardly extending rib in wiping contact with the wall of said axial bore of circular cross-section.

3. The dry disposable nozzle assembly as in claim 1 wherein said ejection orifice of said nozzle has a diameter in the range of from 0.005 inch to about 0.007 inch.