Injection device

• US 3,945,379 A
• Filed: 08/08/1974
• Issued: 03/23/1976
• Est. Priority Date: 08/08/1974
• Status: Expired due to Term

• Current Assignee: Smithkline Beecham Corporation (Smithkline Beecham PLC)
• Original Assignee: SmithKline Corporation (Smithkline Beecham PLC)
• Inventors: Talbert, Sherwood G., Pritz, Howard B.
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Cohen, Lee S.
• Application Number:
  US05/495,625
• Time in Patent Office: 593 Days
• Field of Search: 128/173 H, 128/216, 128/218 R, 128/218 F, 128/218 A, 222/389, 222/327, 239/322
• US Class Current: 604/70
• CPC Class Codes: A61M 2005/312 comprising sealing means, e.g. severable caps, to be removed prior to injection by, e.g. tearing or twisting
• CPC Class Codes: A61M 5/2053 Media being expelled from injector by pressurised fluid or vacuum for infusion A61M5/145, A61M5/155
• 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 5/488 Limiting injection pressure

Abstract

A pressure operated injection device supports an ampul containing a plunger. A ram which actuates the plunger is spring biased to a retracted position and is advanced by a gas under pressure. A source of gas under pressure is connected by a passage to a gas accumulating chamber which in turn is connected by a passage to the ram with a valve being provided in each passage. The valves admit gas to the ram from the accumulating chamber at a predetermined pressure and simultaneously prevent the admission of any further gas from the source of gas and, at a substantially lower pressure, close the passage connecting the accumulating chamber and the ram. The device is constructed to exhaust gas to the atmosphere from the ram as it retracts and a manually controlled valve controlling the flow of gas from the source to control the operation of the device.

Claims

1. A pressure-operated injection device comprising:

a housing,

means to support in the housing an ampul having a plunger and a discharge opening,

a ram slidably mounted in the housing coaxially with the supporting means and adapted to actuate said plunger,

an accumulating chamber in the housing to accumulate gas,

means to supply a gas under prssure to the accumulating chamber,

pressure actuated means responsive to pressure of gas in the accumulating chamber to conduct gas to the ram from the accumulating chamber and stop the supply of gas to the accumulating chamber when the gas pressure in the accumulating chamber reaches a predetermined pressure.

2. A pressure-operated injection device comprising:

a housing,

means to support in said housing an ampul having a plunger and a discharge opening,

a ram slidably mounted in the housing coaxially with the supporting means for actuating said plunger,

means to bias the ram to a retracted position,

an accumulating chamber in said housing for accumulating gas,

a source of gas under pressure,

a first passage connecting the chamber and the ram,

a first pressure actuated valve means controlling said first passage,

said first valve means being spring biased to the closed position, opening responsive to a predetermined pressure and remaining open responsive to a pressure ranging from said predetermined pressure to a predetermined lower pressure,

a second passage connecting the accumulating chamber to the source of gas under pressure,

a second valve means controlling said second passage,

means respeonsive to the opening movement of the first valve means to close the second valve means when the first valve means open and prevent further gas from entering the accumulating chamber, and

a manually controlled valve in said second passage upstream of said second valve.

3. A device in accordance with claim 2 in which the source of gas under pressure comprises a container of liquified gas removably secured to the housing.

4. A device in accordance with claim 2 having means to connect the accumulating chamber to the atmosphere during the retraction of the ram.

5. A device in accordance with claim 2 having means to exhaust gas as the ram retracts including a restricted passage connecting the ram and the accumulating chamber, a check valve in the restricted passage preventing flow from the accumulating chamber to the ram and means to connect the accumulating chamber to the atmosphere.

6. A device in accordance with claim 2 in which the means to bias the ram comprises a compression coil spring.

7. A device in accordance with claim 2 having stop means to limit the extension of the ram.

8. A pressure-operated injection device comprising a housing,

means to support in said housing an ampul having a plunger and a discharge opening,

a ram slidably mounted in the housing coaxially with the supporting means for actuating said plunger,

means to bias the ram in a retracted position,

a source of gas under pressure,

said housing having a cylindrical cavity having a top wall, a bottom wall and a side wall, a gas accumulating chamber in the housing, a first passage connecting the chamber with the top of the cavity, a second passage connecting the source of gas with the chamber and third passage connecting the upper portion of the cavity with the ram,

a piston in said cavity having an upper face facing the top of the cavity,

a first valve member controlling the first passage, operatively connected to the upper face of the piston and having exposed to pressure in said first passage an upper face having a diameter smaller than the diameter of the piston,

a second valve member to control said second passage operatively connected to the piston and movable to a position closing the second passage,

resilient means to bias the piston upwardly to maintain the first valve member closed until a predetermined gas pressure is exerted on the upper face of the first valve member to initiate the downward movement of the piston and expose the piston to the gas pressure to accelerate the downward movement of the piston and the closure of the second valve member and prevent the return of the piston upwardly to close the first valve member until the gas pressure drops substantially below said predetermined pressure in order to supply gas under pressure to said ram to advance it and to provide for exhausting gas back through the first and third passage to the accumulating chamber on the retraction of the ram,

means to connect said accumulating chamber to the atmosphere to exhaust gas therefrom as the ram retracts, and

a normally closed manually controlled valve in said second passage upstream of said second valve member controlling the second passage.

9. A device in accordance with claim 8 in which a fourth passage connects the accumulating chamber to the atmosphere and a normally open manually controlled valve in the fourth passage, said last mentioned manually controlled valve being connected to the first mentioned manually controlled valve.