Medical fluid injector

• US 5,925,022 A
• Filed: 11/10/1998
• Issued: 07/20/1999
• Est. Priority Date: 11/22/1996
• Status: Expired due to Term

• Current Assignee: Liebel-Flarsheim Company (Mallinckrodt plc)
• Original Assignee: Liebel-Flarsheim Company (Mallinckrodt plc)
• Inventors: Neer, Charles S., Wagner, Gary S., Staats, Peter F., Bergen, Robert G., Knipfer, James E., Goethel, James H., Battiato, Dane J., Minnich, John N., Jacobs, Pamela K., Verdino, Steve P.
• Primary Examiner(s): Coggins, Wynn Wood
• Assistant Examiner(s): KENNEDY, SHARON E
• Application Number:
  US09/189,337
• Time in Patent Office: 252 Days
• Field of Search: 604/154, 604/155, 604/65-67, 604/73, 604/151, 604/152, 604/131, 604/123, 604/186, 604/207-211, 604/224, 604/227, 128/DIG. 1, 128/DIG. 13
• US Class Current: 604/208
• CPC Class Codes: A61M 2005/14553 comprising a pressure jacket
• CPC Class Codes: A61M 2205/215 Tilt detection, e.g. for warning or shut-off
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/6018 providing set-up signals for the apparatus configuration
• CPC Class Codes: A61M 5/14546 Front-loading type injectors
• CPC Class Codes: A61M 5/14566 with a replaceable reservoir for receiving a piston rod of the pump
• CPC Class Codes: A61M 5/365 Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: Y10S 128/01 Motorized syringe

Abstract

A medical fluid injector includes: an air detection system for detecting air in the neck of the syringe; a hand-operated control lever for controlling movement of the injector ram; magnetic conductors for delivering magnetic fields from a power head face plate to an internal circuit board to permit detection of different face plates; a tilt sensor detecting the tilt angle of the power head to control the speed of motion brought about by the hand-operated control lever and to control an invertible display; and a monitor microcontroller for monitoring the behavior of the central processing unit to detect and react to error conditions.

Claims

1. An injector for injecting fluids from a syringe into an animal subject, having a hand-operated movement control for controlling movements of said injector, said injector comprising:

a plunger drive ram,

a motor for moving said plunger drive ram,

a syringe mounting for attachment to a syringe to position a syringe relative to said injector to permit said plunger drive ram to engage and move a plunger into or out of said syringe,

a control circuit controlling said motor to move said ram and plunger to inject fluid from said syringe, and

a hand-operated movement control comprising a lever movable between a home position and forward and reverse positions,

said control circuit responding to forward movement of said lever by moving said plunger drive ram into said syringe to expel fluid from the syringe at a rate related to the amount of forward movement of said lever from said home position, said control circuit responding to reverse movement of said lever by moving said plunger drive ram out of said syringe to draw fluid into the syringe at a rate related to the amount of reverse movement of said lever from said home position.

2. The injector of claim 1 wherein said lever is mounted in said injector on a pivot shaft, and further comprising return springs positioned on opposite sides of said lever such that rotation of said lever away from said home position bends said return springs.

3. The injector of claim 2 further comprising a rotational detector attached to said pivot shaft for rotation with said lever to detect an angle of rotation of said lever to produce a rotation angle signal, wherein said control circuit responds to said rotation angle signal by moving said plunger drive ram at a speed related to said rotation angle signal.

4. The injector of claim 3 wherein said control signal moves said plunger drive ram at a speed proportionate to said angle of rotation of said lever.

5. The injector of claim 3 wherein said rotational detector is a rotary potentiomneter.

6. The injector of claim 2 further comprising a rotational detector attached to said pivot shaft for rotation with said lever to detect an angle of rotation of said lever to produce a rotation angle signal, wherein said control circuit responds to said rotation angle signal by moving said plunger drive ram so as to generate an injection pressure related to said rotation angle signal.

7. The injector of claim 2 wherein said return springs and said lever are electrical contacts, and further comprising a safety circuit generating a safety control signal indicating whether there is electrical contact between said return springs and said lever,

said control circuit responding to said safety control signal,

whereby the failure of a return spring is electrically detectable by said control circuit.

8. The injector of claim 2 further comprising a detent spring positioned relative to said lever to engage said lever upon rotation of said lever into a position which is more than a predetermined angle from said home position, said detent spring producing additional resistive torque opposing rotation of said lever away from said home position beyond said predetermined angle.

9. The injector of claim 8 wherein said detent spring is positioned relative to said lever to engage said lever upon rotation of said lever to a reverse position.

10. The injector of claim 9 wherein said detent spring and said lever are electrical contacts, further comprising a detent circuit generating a detent signal indicating whether there is electrical contact between said detent spring and said lever,

said control circuit responding to said detent signal by moving said plunger drive ram out of said syringe to draw fluid into said syringe at a predetermined recommended maximum speed.

11. A method of controlling an injector for injecting fluid from a syringe into an animal subject, using a hand-operated movement control for controlling movements of said injector, the method comprising:

providing an injector having a plunger drive ram, a motor for moving said plunger drive ram, a syringe mounting for attachment to a syringe to position a syringe relative to said injector to permit said plunger drive ram to engage and move a plunger into or out of said syringe, a control circuit controlling said motor to move said ram and plunger to inject fluid from said syringe, and a hand-operated movement control comprising a lever movable between a home position and forward and reverse positions,

responding to forward movement of said lever by moving said plunger drive ram into said syringe to expel fluid from the syringe at a rate related to the amount of forward movement of said lever from said home position, and

responding to reverse movement of said lever by moving said plunger drive ram out of said syringe to draw fluid into the syringe at a rate related to the amount of reverse movement of said lever from said home position.