Failsafe apparatus and method for effecting syringe drive

• US 4,908,017 A
• Filed: 07/31/1987
• Issued: 03/13/1990
• Est. Priority Date: 05/14/1985
• Status: Expired due to Fees

• Current Assignee: Medex Incorporated (Smiths Group International Holdings Ltd.)
• Original Assignee: Ivion Corporation
• Inventors: Oshetski, Walter E., Altobellis, Richard M., Scharf, Bennett J., Fellinger, Michael W., Howson, David C., Popken, John A.
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Lewis, Ralph
• Application Number:
  US07/080,566
• Time in Patent Office: 956 Days
• Field of Search: 604/31, 604/65, 604/67, 604/151, 604/154, 604/155, 604/246, 128/DIG. 1, 128/DIG. 12, 128/DIG. 13
• US Class Current: 604/67
• CPC Class Codes: A61M 2005/31518 designed to reduce the overall size of an injection device, e.g. using flexible or pivotally connected chain-like rod members
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: Y10S 128/01 Motorized syringe
• CPC Class Codes: Y10S 128/12 Pressure infusion

Abstract

Failsafe apparatus and method are disclosed for controlling fluid flow from syringes. One or more syringes are positioned so that the piston of each syringe is caused to be precisely displaced to thereby safely deliver medicament from the syringe to a patient. To effect movement of each piston, a rack is provided, either as a part of the piston or secured thereto, and longitudinal movement of each rack is effected by rotating an associated pinion gear that is connected with a pulse-driven, stepper motor utilized in a power-efficient electromechanical configuration, with the operation of the stepper motor being accomplished through dual-redundant state machines controlled by a pre-programmed memory unit, and with the apparatus being repeatedly subjected to a plurality of error checks and data integrity verifications to assure continued proper operation.

Claims

1. A compact device for controlling delivery of fluid from a syringe having a piston the movement of which in a predetermined direction causes said fluid to be expelled from said syringe, said device comprising:

a stepper motor having a rotatable motor shaft;

pulse generating means including first and second state machines operating in parallel with respect to one another and connected in common with said stepper motor to provide pulses thereto, when said first and second state machines provide like outputs, for causing rotation of said motor shaft by increments, said first and second state machines including error monitoring means for monitoring said device to determine error in delivery of fluid from said syringe and precluding application of pulses to said stepper motor when said error is determined by said error monitoring means to thereby enhance safe delivery of fluid from said syringe; and

motion translation means connected with said motor shaft and adapted to be connected with said piston for causing movement of said piston in said predetermined direction in response to said incremental rotation of said motor shaft.

2. The device of claim 1 wherein said device includes battery means for providing the sole power for powering said device.

3. The device of claim 1 wherein said motion translation means includes a rack for connection with said piston and a pinion driven by said motor shaft through a gearing arrangement.

4. The device of claim 3 wherein said rack is formed by a plurality of hinged segments.

5. The device of claim 1 wherein said motion translation means includes a one-way ball drive engagable with said motor shaft to permit rotation of said motor shaft in only one predetermined direction.

6. The device of claim 1 wherein said pulse generating means includes a pair of clocking means each of which is connected with said first and second state machines to further reduce error by requiring predetermined agreement between each of said clocking means.

7. A compact device for controlling delivery of fluid from a syringe having a piston the movement of which in a predetermined direction causes said fluid to be expelled from said syringe, said device comprising:

a stepper motor having a rotatable motor shaft;

pulse generating means connected with said stepper motor to provide pulses thereto for causing rotation of said motor shaft by increments, said pulse generating means including means providing data for enabling pulse creation and error monitoring means for determining error in delivery of fluid from said syringe and precluding application of pulses to said stepper motor when said error is determined by said error monitoring means to thereby enhance safe delivery of fluid from said syringe, said error monitoring means including verifying means for verifying the integrity of said data utilized in causing said pulse generating means to create said pulses; and

motion translation means connected with said motor shaft and adapted to be connected with said piston for causing movement of said piston in said predetermined direction in response to said incremental rotation of said motor shaft.

8. A compact device for controlling delivery of fluid from a syringe having a piston the movement of which in a predetermined direction causes said fluid to be expelled from said syringe, said device comprising:

a stepper motor having a rotatable motor shaft;

pulse generating means connected with said stepper motor to provide pulses thereto for causing rotation of said motor shaft by increments;

braking means connected with said stepper motor to cause termination of rotation of said motor shaft upon termination of each of said pulses applied to said motor shaft by said pulse generating means; and

motion translation means connected with said motor shaft and said piston for causing movement of said piston in said predetermined direction in response to said incremental rotation of said motor shaft, said motion translation means including a gearing arrangement having apertures therein, a rack adapted to be connected with said piston and having distinguishable stripes thereon, and a pinion connected with said stepper motor through said gearing arrangement;

a first sensor responsive to said distinguishable stripes on said rack; and

a second sensor responsive to movement of said apertures in said gearing arrangement to thereby determine that fluid has been discharged from said syringe.

9. The device of claim 8 wherein said device includes power supply means adapted to receive a pair of batteries, said batteries providing the sole power for operation of said device, and said power supply means being configured so that either of said batteries can power the device in the absence of power supplied from the other.

10. The device of claim 8 wherein said pulse generating means includes error monitoring means for determining error in delivery of fluid from said syringe and precluding application of pulses to said stepper motor when said error is determined by said error monitoring means to thereby enhance safe delivery of fluids from said syringe.

11. In a device for effecting delivery of fluid through movement of a discharge causing element, a control system for controlling movement of said discharge causing element, said control system comprising:

profile carrying means for providing a predetermined profile of fluid to be delivered, said profile carrying means including a removable logic cartridge;

drive means connected with said profile carrying means for providing an output for causing movement of said discharge causing element according to said profile, said drive means including first and second substantially identical state machines connected with said removable logic cartridge and in parallel with respect to one another and providing independent outputs, said first and second state machines including error determining means to determine error in said drive means by comparison of said independent outputs, said error determining means also being responsive to said profile carrying means for determining error in said profile as well as in said drive means and providing an error indication in response thereto; and

means for receiving said error indications and responsive thereto providing at least one of an error indication and termination of fluid delivery.

12. The system of claim 11 wherein said system includes first and second clocking means which operate at the same frequency and each of which is connected with different ones of said first and second state machines.

13. The system of claim 11 wherein said state machines also provide a plurality of data integrity verifications.

14. A method for monitoring safe delivery of fluid from a syringe having a piston the movement of which is effected by electronic signals supplied to a piston actuating element, said method comprising:

providing a profile of fluid flow to be delivered from said syringe;

providing first and second substantially identical state machines for generating said electronic signals responsive to said profile of fluid and coupling said electronic signals to said piston actuating element;

monitoring operation of said state machines and said profile of fluid to be delivered by providing separate outputs from each of state machines and comparing said outputs to enhance safe operation of said state machines by detecting errors therein; and

utilizing detected errors to effect safe operation of said state machines by at least one of indicating said detected errors and terminating delivery of fluid from said syringe.

15. The method of claim 14 wherein said method includes monitoring said state machines at least every sixty seconds to determine if error exists therein.

16. A method for monitoring safe delivery of fluid from a syringe having a piston the movement of which is effected by electronic signals supplied to a piston actuating element, said method comprising:

providing a profile in one minute increments of fluid flow to be delivered from said syringe;

providing a state machine for successively obtaining each one minute increment of fluid flow profile and generating therefrom said electronic signals responsive to said increment of fluid flow profile then obtained and coupling said electronic signals to said piston actuating element;

monitoring operation of said state machine and said profile of fluid then to be delivered to detect errors therein; and

utilizing detected errors to effect safe operation of said state machine by at least one of indicating said detected errors and terminating delivery of fluid from said syringe.

17. The method of claim 16 wherein said method includes preparing said fluid flow profile for a time period of up to 31 days for effecting delivery of fluid from said syringe.

18. A device for monitoring safe delivery of fluid from a syringe having a piston the movement of which in a direction to expel fluid from said syringe is effected by electronic signals supplied to a piston actuating element, said device comprising:

control means providing a profile of fluid flow to be delivered from said syringe;

signal generating means having first and second substantially identical state machines connected with said control means for generating said electronic signals responsive to said profile of fluid from said control means and coupling said electronic signals to said piston actuating element, said first and second state machines including monitoring means for monitoring operation of said state machines and said profile of fluid to be delivered by comparing separate outputs from each of said state machines to enhance safe operation of said state machines by detecting errors therein; and

utilization means connected with said monitoring means and utilizing detected errors received therefrom to effect safe operation of said state machines by at least one of indicating said detected errors and terminating delivery of fluid from said syringe.