Piston drive arrangement for injector

• US 4,346,707 A
• Filed: 03/27/1981
• Issued: 08/31/1982
• Est. Priority Date: 01/08/1979
• Status: Expired due to Fees

• Current Assignee: Douglass G. Whitney, John K. Martin III
• Original Assignee: Douglass G. Whitney, John K. Martin III
• Inventors: Whitney, Douglass G., Martin, John K. III
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US06/248,484
• Time in Patent Office: 522 Days
• Field of Search: 128/214 F, 128/214 R, 128/214 E, 128/214, 128/215, 128/216, 128/218 A, 128/221, 128/253, 128/260, 128/234, 128/DIG. 1, 128/DIG. 12, 222/63, 222/70, 222/77
• US Class Current: 604/155
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61M 2005/14506 mechanically driven, e.g. spring or clockwork
• CPC Class Codes: A61M 2205/0294 Piezoelectric materials
• CPC Class Codes: A61M 39/04 having pierceable self-sealing members
• CPC Class Codes: A61M 5/1422 with double acting or multiple pistons
• 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 5/155 pressurised by gas introduced into the reservoir
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: Y10S 128/01 Motorized syringe
• CPC Class Codes: Y10S 128/12 Pressure infusion
• CPC Class Codes: Y10S 128/13 Infusion monitoring

Abstract

Method and apparatus for injecting fluids into patients at a controlled rate from an ampule containing the injecting fluid with a sliding piston therein to force the fluid from the ampule into the patient using a drive system which incrementally and successively advances the piston in the ampule to meter the fluid into the patient.

Claims

1. In an apparatus for dispensing liquid including a liquid chamber with an outlet slidably mounting a piston therein for sliding movement axially along an expelling axis toward the outlet to force liquid from the outlet and a drive member movable axially along the expelling axis to engage and force the piston toward the outlet;

the improvement comprising;

a pointed driving projection on that end of said drive member facing the piston coaxially aligned with the expelling axis; and

a driven member carried by the piston, said driven member defining a conical bearing surface thereon opening toward said pointed driving projection and having an apex in registration with said expelling axis, said conical bearing surface angling away from said expelling axis with equal angles therearound so that said pointed driving projection engages said conical bearing surface in said apex to axially move said piston along said expelling axis with the force exerted on said piston by the drive member equally distributed circumferentially about said piston to prevent canting of said piston in said liquid chamber.