HYPODERMIC INJECTION DEVICE WITH SHOCK ABSORBING SPRING

• US 3,797,489 A
• Filed: 02/10/1972
• Issued: 03/19/1974
• Est. Priority Date: 02/10/1972
• Status: Expired due to Term

• Current Assignee: Stanley J. Sarnoff
• Original Assignee: Stanley J. Sarnoff
• Inventors: Sarnoff, Stanley J.
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): McGowan, J. C.
• Application Number:
  US05/225,123
• Time in Patent Office: 768 Days
• Field of Search: 128/215,218R,218F,218D,218DA,218A
• US Class Current: 604/136
• CPC Class Codes: A61M 2005/206 With automatic needle insertion
• CPC Class Codes: A61M 2005/2073 preventing premature release, e.g. by making use of a safety lock
• CPC Class Codes: A61M 5/2033 Spring-loaded one-shot injectors with or without automatic needle insertion multishot dosing syringes A61M5/31525, needle insertion only A61M5/3287
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/28 Syringe ampoules or carpules, i.e. ampoules or carpules provided with a needle

Abstract

A hypodermic injection device is provided comprising a cylindrical holder closed at one end and slidably carrying an ampoule with attached cannula facing the closed end of the holder, medicament is provided in the ampoule between the cannula and the piston in the ampoule, a gun spring assembly is associated with the holder and in operative association with the ampoule to force the ampoule and attached cannula forward thus driving the cannula out of the closed end of the holder and into the locus of injection, and a counterbalancing spring is positioned in the holder between the closed end thereof and the cannula end of the ampoule to counteract the gun spring force.

Claims

1. In a hypodermic injection device comprising a gun, a cartridge holder having a closed end and in operative relationship to the gun, a cartridge within the holder, said gun comprising a sleeve open at one end thereof, a plunger positioned within the sleeve, spring power means acting on said plunger tending to move it out the open end of the sleeve, restraining means cooperating with said plunger to prevent plunger movement, safety means acting on said restraining means to render it inoperative, said cartridge holder comprising a hollow shell acting as a prolongation of the gun sleeve, a puncturable seal closing off the end of the holder remote from the gun, said cartridge including an ampoule comprising a hollow cylindrical sleeve, a piston slidably positioned in one end thereof and means mounting a cannula extending from and closing off the other end, a fluid within the cylindrical sleeve between the piston and the cannula, the cartridge fitting within the cartridge holder with the free end of the cannula within the closed end of the holder, the improvement comprising:

shock absorbing and retracting spring means interposed between the cannula end of the cartridge and the closed end of the cartridge holder, said shock absorbing and retracting spring means being sized whereby it is compressed by the cartridge and acts as a shock absorber as said cartridge moves under the force of the spring power means until the cannula is fully projected into the patient, the shock absorbing and retracting spring means being further characterized by having a compressed spring force when the cannula is fully projected into the patient and injection begins under the continuing expansion of the spring power means to overcome the force of the spring power means and retract the cannula while injection continues and is completed.

2. The invention as set forth in claim 1 and wherein the shock absorbing and retracting means comprises a coiled spring positioned around the cannula between the cannula end of the cartridge and the closed end of the cartridge holder.

3. The invention as set forth in claim 2 and wherein the coiled spring is a helical spring.

4. The invention as set forth in claim 1 and wherein the hollow cylindrical ampoule sleeve is necked down at its cannula end to form a cylindrical projection of reduced diameter, an annular flange formed on the end of said projection, and a cannula sleeve connected to the cannula and fitting over the flange to secure the cannula to the ampoule and further wherein the shock absorbing and retracting spring means comprises a helical spring fitting around the cannula and abutting that portion of the ampoule cylinder around the cylindrical portion of reduced diameter and the closed end of the cartridge holder.

5. The invention as set forth in claim 1 and wherein the hollow cylindrical ampoule sleeve is necked down at its cannula end to form a cylindrical projection of reduced diameter, an annular flange formed on the end of said projection, and a cannula sleeve connected to the cannula, said cannula sleeve having a portion secured to the cannula and an enlarged portion fitting over and secured to the flange and further wherein the shock absorbing and retracting spring means comprises a helical spring fitting around the cannula and abutting the enlarged portion of the cannula sleeve and the closed end of the cartridge holder.

6. The invention as set forth in claim 4 and wherein a resilient washer is positioned between the helical spring and the ampoule cylinder.