Device for intramuscular injections, especially of insulin

• US 4,231,368 A
• Filed: 03/20/1979
• Issued: 11/04/1980
• Est. Priority Date: 03/23/1978
• Status: Expired due to Term

• Current Assignee: Michael Becker
• Original Assignee: Michael Becker
• Inventors: Becker, Michael
• Primary Examiner(s): Yasko, John D.
• Application Number:
  US06/022,374
• Time in Patent Office: 595 Days
• Field of Search: 128/236, 128/234, 128/218 A, 128/218 F, 128/215, 128/224
• US Class Current: 604/157
• CPC Class Codes: A61M 2005/2418 comprising means for damping shocks on ampoule
• CPC Class Codes: A61M 2005/3152 including gearings to multiply or attenuate the piston displacing force
• CPC Class Codes: A61M 5/1782 Devices aiding filling of syringes in situ combination of a vial and a syringe for transferring or mixing their contents A61J1/2096, filling of medical containers in general B65B3/003
• CPC Class Codes: A61M 5/20 Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically A61M5/142 , A61M5/46 take precedence; hypodermic projectiles F42B12/54
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence

Abstract

A pistol-like casing provides for mounting a tubular holder containing a syringe in the gun barrel portion of the casing so it may be cocked in the withdrawn position against the force of a spring and released by movement of an arresting pawl. Pulling back a trigger advances a push rod that first trips the pawl, then brings force to bear against the piston rod of the syringe. After the needle is driven into the skin by the release of the pawl and the actuating mechanism has been brought to bear against the syringe piston-rod, the injection of the syringe contents can proceed under control of hand feel without any necessity of changing or shifting the hand grip, by simply continuing to pull the trigger back.

Claims

1. A device for intramuscular injection capable of meeting the requirements of the administration of insulin, comprising a casing having a stationary grip member and, also, a guideway for displaceably mounting a syringe contained in a holder for a limited displacement in said guideway, a first spring for urging said syringe holder forward in said guideway, cocking means including an arresting pawl for releaseably holding said syringe holder against the force of said spring in a withdrawn position ready for use, and hand operable means (3) provided in said casing and operable by a single controllable continued interruptable movement of the same hand that holds the casing, to cause the syringe as a whole to be shot forward in response to displacement of said arresting pawl and, thereafter, to operate the syringe by bringing force to bear against the piston-rod (7, 7a) thereof, said hand operable means including:

a push-rod (23) mounted in said casing (2) for longitudinal movement therein and having a front end (23a) arranged for acting on said arresting pawl (17) for displacement thereof, and equipped at its rear end (23b) with hell-mounted means (30) for establishing contact with and bearing directly on the rear end of said piston rod (7, 7a) of said syringe (4) after said arresting pawl has been displaced to release said syringe, said push rod (23) being provided with a rack by engagement of which it may be longitudinally propelled;

a second rod (34) provided with a rack, mounted in said casing for movement parallel to the direction of movement of said push rod;

a rotary gear (38) for communicating movement between said second rod and said push rod, mounted between said rods in said casing and engaging the racks thereof;

a second spring acting on one of said rods so as to oppose forward movement of said push rod;

a pull-trigger (41) rigidly connected to a member of a rod system constituted by said push rod and said second rod, said pull-trigger being part of a slide mounted in said casing so as to be displaceable, with respect to the stationary grip portion (42) of said casing, parallel to the displacement of said rods, the displacement of said trigger being proportional to the the displacement of said piston rod of said syringe when contact is established between said push rod and said piston rod; and

a heel (26) on the rear end of said push-rod having an adjusting device (27) thereon for adjustably mounting said means (30) for establishing contact with the piston rod of said syringe, said adjusting device comprising a threaded spindle (28).

2. An intramuscular injection device as defined in claim 1 in which said hand-operated means (3) includes a pivotally mounted intermediate lever (24) in said casing, located therein operatively between said arresting pawl (17) and the path of said push-rod (23) for transfer of force from said push-rod to said pawl.

3. An intramuscular injection device as defined in claim 1 or claim 2, in which a third spring (19) is arranged to bear on said pawl (17) to facilitate cocking said syringe holder in position.

4. An intramuscular injection device as defined in claim 1 or claim 2, in which said guideway is constituted as a removable shell (11) for displaceably containing said syringe holder (9), and in which said casing is provided with means for mounting said shell, and in which, further, said first spring is a tension spring anchorable at one end in a portion of said casing mounting said shell and attachable at its other end to said syringe holder, said shell having an abuttment (48) for the forward position of said syringe holder and also having a head portion (12) provided with an aperture for the passage of the needle of said syringe.

5. An intramuscular injection device as defined in claim 4, in which said shell has a tubular threaded portion and in which said head portion (12) is mounted by screw threads on said threaded portion of said shell, in which, further said shell is equipped with an extension shell (45) seating a container (46) or a sealing cap (50), said extension shell being shaped so that it can be pushed onto or removed from said head portion (12) of said shell.